ALBERT

Description: 〈p〉Publication date: Available online 8 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Computational Physics〈/p〉 〈p〉Author(s): Maxim Rakhuba, Alexander Novikov, Ivan Oseledets〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Such problems as computation of spectra of spin chains and vibrational spectra of molecules can be written as 〈em〉high-dimensional eigenvalue problems〈/em〉, i.e., when the eigenvector can be naturally represented as a multidimensional tensor. Tensor methods have proven to be an efficient tool for the approximation of solutions of high-dimensional eigenvalue problems, however, their performance deteriorates quickly when the number of eigenstates to be computed increases. We address this issue by designing a new algorithm motivated by the ideas of 〈em〉Riemannian optimization〈/em〉 (optimization on smooth manifolds) for the approximation of multiple eigenstates in the 〈em〉tensor-train format〈/em〉, which is also known as matrix product state representation. The proposed algorithm is implemented in TensorFlow, which allows for both CPU and GPU parallelization.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 8 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Computational Physics〈/p〉 〈p〉Author(s): Chen Liu, Florian Frank, Faruk O. Alpak, Béatrice Rivière〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Permeability estimation of porous media from directly solving the Navier–Stokes equations has a wide spectrum of applications in petroleum industry. In this paper, we utilize a pressure-correction projection algorithm in conjunction with the interior penalty discontinuous Galerkin scheme for space discretization to build an incompressible Navier–Stokes simulator and to use this simulator to calculate permeability of real rock samples. The proposed method is accurate, numerically robust, and exhibits the potential for tackling realistic problems.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 8 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Computational Physics〈/p〉 〈p〉Author(s): Mustapha Malek, Nouh Izem, M. Shadi Mohamed, Mohammed Seaid, Omar Laghrouche〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An efficient partition of unity finite element method for three-dimensional transient diffusion problems is presented. A class of multiple exponential functions independent of time variable is proposed to enrich the finite element approximations. As a consequence of this procedure, the associated matrix for the linear system is evaluated once at the first time step and the solution is obtained at subsequent time step by only updating the right-hand side of the linear system. This results in an efficient numerical solver for transient diffusion equations in three space dimensions. Compared to the conventional finite element methods with 〈em〉h〈/em〉-refinement, the proposed approach is simple, more efficient and more accurate. The performance of the proposed method is assessed using several test examples for transient diffusion in three space dimensions. We present numerical results for a transient diffusion equation with known analytical solution to quantify errors for the new method. We also solve time-dependent diffusion problems in complex geometries. We compare the results obtained using the partition of unity finite element method to those obtained using the standard finite element method. It is shown that the proposed method strongly reduces the necessary number of degrees of freedom to achieve a prescribed accuracy.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 8 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Computational Physics〈/p〉 〈p〉Author(s): Lahbib Bourhrara〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This document presents a new numerical scheme dealing with the Boltzmann transport equation. This scheme is based on the expansion of the angular flux in a truncated spherical harmonics function and the discontinuous finite element method for the spatial variable. The advantage of this scheme lies in the fact that we can deal with unstructured, non-conformal and curved meshes. Indeed, it is possible to deal with distorted regions whose boundary is constituted by edges that can be either line segments or circular arcs or circles. In this document, we detail the derivation of the method for 2D geometries. However, the generalization to 2D extruded geometries is trivial.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Shuai Zhao, Wanfen Pu, Mikhail A. Varfolomeev, Chengdong Yuan, Shan Qin, Liangliang Wang, Dmitrii A. Emelianov, Artashes A. Khachatrian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Because the thermal release correlates directly with the success of in-situ combustion (ISC) technology, this research performs a series of investigations concerning thermal behavior and kinetics of heavy crude oil during combustion using high pressure differential scanning calorimetry (HP-DSC) and accelerating rate calorimetry (ARC). The results obtained from HP-DSC profiles indicated that for oil alone and its mixtures with quartz sand/crushed core, the peak temperature was lowered, and the heat flow increased with increasing oxygen partial pressure. The heat enthalpy of low temperature oxidation (LTO) was higher than that of high temperature oxidation (HTO) under oxygen partial pressures of 0.5, 1 and 1.5 MPa, and the increase in heat enthalpy of LTO with oxygen partial pressure was more pronounced than that of HTO. Unlike the crushed core, the addition of quartz sand delayed exothermic oxidation reactions. Compared with oil only and oil + quartz sand, the LTO and HTO peak temperatures of oil + crushed core were considerably lowered, and the effect of crushed core on increasing heat release for LTO at oxygen partial pressure of 1.5 MPa was more prominent. It was observed that the heat enthalpy of LTO and HTO increased quasi-linearly with the oxygen partial pressure in both the presence and absence of quartz sand/crushed core. ISC might be considered as an appropriate candidate for Jiqi block, based on exothermic continuity of the ARC curves, with the near-wellbore zone of target block heated to 180 °C where the exothermic oxidation activity is notably intensified. The kinetic results showed that the LTO and HTO intervals were divided into 6 and 2 subintervals, respectively, which facilitated more precise modelling of the ISC process.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Zan Chen, Menglu Lin, Shuhua Wang, Shengnan Chen, Linsong Cheng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Studies have shown that the gas huff and puff injection potentially perform better than the continuous gas flooding in enhancing the hydrocarbon recovery in the liquid rich tight reservoirs. During the fracturing stimulation, only part of the induced hydraulic fractures is propped because proppants cannot be carried to the fracture tips. Moreover, some secondary and tertiary fractures may be too narrow to accommodate any proppants. The conductivity of the unpropped fractures is highly dependent on the variation of the in-situ pressure and may be open and close periodically during the huff-n-puff cycles. In this study, the stress-dependent fracture conductivity and its impact on the produced gas huff-n-puff performance are investigated in a liquid rich tight reservoir, considering the existence of the large amount of the unpropped fractures. The experimental data of stress-dependent fracture conductivity is employed first to simulate the dynamic conductivity during the depletion and the gas huff and puff cycles. A reservoir model is then constructed and history-matched based on the reservoir fluid samples and the field production data collected from the Montney liquid rich tight reservoir in Western Canada. Performance of the produced gas huff-n-puff is examined in the targeted reservoir and results show that contributions of the unpropped fractures cannot be ignored, which leads to 7.8% more condensate (i.e., oil) production and 2.8% higher in barrel of oil equivalent (BOE), compared to the case with propped fractures only. The effects of complex fracture geometry and the cluster completion are also investigated and results show that the unpropped fracture contributions towards the condensate production and BOE are even more pronounced in the complicated scenarios. The condensate oil and BOE are 42.0% and 22.9% higher in complex fracture geometry case and 12.4% and 5.6% higher in the fractures with multiple clusters than those scenarios with propped fractures only. This paper provides a better understanding on the potential performance of enhanced hydrocarbons recovery in liquid rich tight gas reservoirs via gas huff-n-puff operations.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Abdelrahman Elkhateeb, Reza Rezaee, Ali Kadkhodaie〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Traditionally, prediction of facies and permeability for a reservoir rock was one of many challenges in the industry that necessitates advanced and sophisticated evaluation for effective reservoir description. Three wells have been studied in the Perth Basin in Western Australia across the shaly sand of the Irwin River Coal Measures Formation, which contain a comprehensive suite of advanced and conventional logs. Due to the reservoir heterogeneity and the clay distribution, it is very challenging to resolve the effective pore volume, the reservoir facies and how the high permeability zones are distributed within the formation.〈/p〉 〈p〉In this paper, a new technique has been successfully tested on the Shaly Sand by integrating the nuclear magnetic resonance (NMR) and the conventional density log. The method allows the establishment of high-resolution facies classification for the reservoir using an Equivalent Flow Zone Indicator Index (EFZI). The studied core facies have been integrated with the EFZI into a new workflow to distribute facies on a larger scale in the uncored wells.〈/p〉 〈p〉Four hydraulic flow units (HFU) have been defined from one cored well using Flow Zone Indicator approach, with each has a unique FZI value and different permeability model based on core measurements. The EFZI-based high-resolution facies have been validated at several formation depths using the core thin sections to ensure the best calibration will be obtained for facies log, hence the permeability log-to-core match.〈/p〉 〈p〉The methodology will help running an advanced petrophysical analysis for the zone of interest and will reduce the parameters uncertainty. Application of this methodology in the uncored wells has shown very encouraging results, which is believed it can be used in the absence of any core data to resolve the rock typing from the well logs.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Atousa Heydari, Kiana Peyvandi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, the stainless steel mesh was used to study the effect of metallic porous media on the formation of methane hydrate and some parameters such as induction time, the kinetics growth and the mole of gas consumed have been investigated at a temperature of 3 °C (276.15 K) and a pressure of 760 psi (5.24Mpa). The metallic porous media was able to show better results on the methane hydrate formation relative to the silica gel. Hence the induction time and, eventually, the total time of the hydrate formation process decreased by about 60%. The kinetics growth and the amount of gas consumed increased significantly. Also, the effect of two types of anionic and nonionic surfactants as kinetics promoters studied in this porous media. The result of adding SDS and SDBS at a concentration near the CMC designated that the induction time lasted nearly zero and the total time of the process by SDBS was minimal. It should be noted that the non-ionic surfactant SPAN 80 could not have a positive effect on this porous media. In general, therefore, the results of this research attempts to show that the stainless steel mesh with SDBS possessed high potential in obtaining the industrial purpose of gas hydrate growth and also was significant in the field of energy storage and transport.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0920410519306473-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Shuaishuai Jiang, Xuehua Chen, Yingkai Qi, Wei Jiang, Jie Zhang, Zhenhua He〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The frequency-dependent attenuation and velocity dispersion of seismic responses are closely related to hydrocarbon reservoirs. To further investigate the characteristics of seismic responses caused by pore fluid-bearing reservoirs, the role of gas saturation is analyzed in seismic responses of sand reservoirs characterized by the patchy saturation model. To this end, a novel wave extrapolation method is developed based on the diffusive-viscous wave equation (DVWE) as well as a scheme for an extended local Rytov Fourier (ELRF) approximation within the extrapolation depth interval. Our proposed method considers the presence of fluid mixtures in the porous media, resulting in seismic attenuation and dispersion by the mechanism generally known as wave-induced fluid flow (WIFF). This method enables an accommodation for the lateral variations in slowness, diffusion coefficient and viscosity. Subsequently, the extrapolation is adopted to model the synthetic seismic data of a distributary channel model. During this modeling, a gas-water saturated sand reservoir embedded into one of the channels was used to comparatively analyze the distinct features on its seismic synthetic data. We exhibited the numerical simulation results using the proposed wave extrapolation method here and the traditional acoustic wave equation (AWE) method. A comparison of the simulation results, demonstrates that our proposed numerical method can depict the seismic dispersion and frequency-dependent attenuation as well as the phase delay effects associated with gas-water-saturated sand reservoirs. Furthermore, we compare the seismic responses by changing the gas saturations of the sand reservoir. The gas saturation of the reservoir has significant effects on the seismic characteristics of the numerical modeling data. The numerical modeling method improves our understanding of the mechanisms of seismic frequency-dependent characteristics associated with gas saturations and potentially contributes to better insights into gas reservoir indicators derived from seismic field data.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Geosciences, Volume 132〈/p〉 〈p〉Author(s): T. Carlotto, P.L.B. Chaffe〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Streamflow recession analysis is crucial for understanding how catchments release water in periods of drought and therefore is important for water resources planning and management. Despite there being several theories on how to model recession curves, few studies compare the different approaches to that problem. In this work, we developed the Master Recession Curve Parameterization tool (MRCPtool), which brings together a set of automated methods for the analysis of recession periods based only on streamflow data. The methods include: (i) hydrograph separation using numerical filters; (ii) automatic extraction of recession periods; (iii) creation of the MRC with the matching strip method; (iv) creation of the MRC for different flow classes defined from the flow duration curve; (v) analysis of flow recession rates 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" altimg="si1.svg"〉〈mrow〉〈mo〉(〈/mo〉〈mo linebreak="goodbreak" linebreakstyle="after"〉−〈/mo〉〈mi〉d〈/mi〉〈mi〉Q〈/mi〉〈mo〉∕〈/mo〉〈mi〉d〈/mi〉〈mi〉t〈/mi〉〈mo〉)〈/mo〉〈/mrow〉〈/math〉 as a function of flow 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" altimg="si2.svg"〉〈mrow〉〈mo〉(〈/mo〉〈mi〉Q〈/mi〉〈mo〉)〈/mo〉〈/mrow〉〈/math〉 and (vi) creation of the MRC from simulated recession curves with different analytical approaches, including linear and nonlinear models. The MRCPtool contains a graphical user interface developed in MATLAB software that facilitates the analysis of streamflow datasets. Finally, we present an example application of the MRCPtool using a streamflow dataset of 44 years. The MRCPtool is an open source tool that can be downloaded from the site: 〈a href="http://www.labhidro.ufsc.br/static/software/MRCPtool.rar" target="_blank"〉http://www.labhidro.ufsc.br/static/software/MRCPtool.rar〈/a〉.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Ultramicroscopy, Volume 206〈/p〉 〈p〉Author(s): P. Kükelhan, T. Hepp, S. Firoozabadi, A. Beyer, K. Volz〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Quantitative scanning transmission electron microscopy (STEM) is a powerful tool for the characterization of nano-materials. Absolute composition determination for ternary III–V semiconductors by direct comparison of experiment and simulation is well established. Here, we show a method to determine the composition of quaternary III–V semiconductors with two elements on each sub lattice from the intensities of one STEM image. As an example, this is applied to (GaIn)(AsBi). The feasibility of the method is shown in a simulation study that also explores the influence of detector angles and specimen thickness. Additionally, the method is applied to an experimental STEM image of a (GaIn)(AsBi) quantum well grown by metal organic vapour phase epitaxy. The obtained concentrations are in good agreement with X-ray diffraction and photoluminescence results.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biomass and Bioenergy, Volume 127〈/p〉 〈p〉Author(s): Shuping Zhang, Shuguang Zhu, Houlei Zhang, Xinzhi Liu, Huiyan Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Effect of combined pretreatment on the mechanism of pyrolysis behavior and pyrolysis products (bio-oil, non-condensable gas and char) of rice husk was investigated using thermogravimetric analyzer (TGA) and laboratory-scale fixed-bed reactor. A coupling method combining iso-conversional method and model-fitting method was used to obtain the pyrolysis kinetic parameter. Pyrolysis kinetics results indicated that activation energy (〈em〉E〈/em〉) gradually increased with the increase of conversion rate (〈em〉α〈/em〉), which was due to the differences in thermal stability of biomass components. Acid washing pretreatment slightly increased the average activation energy (〈em〉E〈/em〉〈sub〉a〈/sub〉), and then subsequent torrefaction process further increased it. The entire pyrolysis reaction process of all the rice husk samples can be described by the reaction-order model. In addition, a laboratory-scale fixed-bed reactor was used to investigate the yields and detailed characteristics of pyrolysis products. The results suggested that phenols and sugars contents in bio-oil increased, while that of small-molecule components with high thermal instability decreased, which was favor for the storage and subsequent utilization of bio-oil. Rice husk char obtained from pyrolysis also has the potential for preparation of silica products. We concluded that combined pretreatment of washing and torrefaction significantly improved the thermochemical utilization potential of rice husk for fuels and chemicals by pyrolysis.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0961953419302429-fx1.jpg" width="307" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Jingyi Zhu, Zhaozhong Yang, Xiaogang Li, Zhichao Song, Ziwei Liu, Shiyi Xie〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Liquid foam is an alternative to water-based fracturing fluid due to its great proppant suspension ability. In this work, theoretical and experimental investigations on the settling behavior of the proppants in viscoelastic foams were analyzed on bubble scale. Settling trajectory was captured over time by optical microscope to calculate proppant settling velocity. At room temperature, proppants kept suspended well, but noticeable changes in proppant position could be observed at 70 °C. We concluded that the sedimentation of the proppants at high temperature was divided into three stages, that were drainage-dominated, structure-dominated and fluid-dominated regimes. For the large proppants, quick settling velocity was seen at first due to fast drainage rate. Then bubble pressure force and network force served as drag force exerting on the proppants when the proppants stretched or squeezed the liquid films. During this regime, bubble distribution, the existence of nodes, the length and the orientation of Plateau border leaded to the fluctuation in settling velocity. Lastly, the proppants would also flow freely along Plateau border over time, and the properties of the foam fluid such as viscosity and elasticity provided the drag force to prevent the proppants from settling. It's more likely for small proppants to change to this stage called fluid-dominated regime, but elasticity also guaranteed their low settling velocity. Moreover, in the existence of proppants, the analysis into drainage rate and bubble structure demonstrated the high stability of viscoelastic foams. These results helped understand the sedimentation of proppants in wet foams and broadened the application of viscoelastic foams in hydraulic fracturing.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Zhong-Zhen Chen, Hong-Ze Gang, Jin-Feng Liu, Bo-Zhong Mu, Shi-Zhong Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A thermal-stable and salt-tolerant biobased zwitterionic surfactant 〈em〉N, N〈/em〉-Dimethyl-〈em〉N〈/em〉-[2-hydroxy-3-sulfo-propyl]-〈em〉N〈/em〉′-phenyloctadecanoyl-1, 3-diaminopropane (SPODP) was successfully obtained from modification of oleic acids which can be regenerated from waste cooking oils, and its structure was characterized using GC-MS, ESI-MS and 〈sup〉1〈/sup〉H NMR approaches. The biobased zwitterionic surfactant demonstrated a strong interfacial activity at high salinity and high temperature conditions at a very low surfactant dosage in formation brine. The ultralow interfacial tension (≤10〈sup〉−3〈/sup〉 mN/m) between crude oil and brine was reached at 0.5 g/L in brine with a wide range compatibility of NaCl up to saturation, Ca〈sup〉2+〈/sup〉 up to 500 mg/L, and temperature up to 95 °C. Meanwhile, it also exhibited strong wetting ability and resistance against adsorption on sands. All the results from this study suggest that the biobased zwitterionic surfactant is promising over varieties of traditional surfactants in applications in alkali free systems in enhanced oil recovery (EOR).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Zhihua Wang, Ye Bai, Hongqi Zhang, Yang Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Waxy crude oil emulsions exhibit gelation behavior, with nucleation observed within a certain temperature range. A kinetic model was developed and validated based on the thermal parameters obtained from differential scanning calorimetry cooling thermograms, and the nucleation rates of various water-in-waxy crude oil emulsions were determined in the temperature range in which gelation occurs. Although temperature had a dominant effect on the gelation and nucleation behavior of waxy crude oil emulsions, the nucleation rate also increased as the water volume fraction in the emulsion increased. Emulsified water droplets with smaller radii can be completely covered by wax particles, inducing a greater nucleation rate. Subjecting the emulsions to a greater shearing strength also increased the nucleation rate. This study provided new insights into the nucleation processes that occur during the formation of waxy crude oil emulsion gels and, in particular, the role of the emulsification properties.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0920410519306424-fx1.jpg" width="496" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Radiation Measurements〈/p〉 〈p〉Author(s): Hui-Yu Tsai, Hsin-Yu Chen, Ming-Wei Lee, Ze Wang, Sheng-Pin Tseng, Ji-Hong Hong, Meei-Ling Jan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Prompt-gamma Compton imaging (PGCI) has been presented as a promising 〈em〉in-vivo〈/em〉 method for proton range verification. An accurate estimation of the Bragg-peak position can potentially be achieved by imaging high-energy prompt-gamma rays (in the range of several MeV). Therefore, scintillation detectors with thick and high Z crystals are mostly used as Compton absorbers for high-energy gamma-ray detection. However, an absorber using thick crystals degrades the angular resolution unless the absorber can provide continuous depth-of-interaction (DOI) measurement. The study investigated various detector configurations using thick crystals for developing a Compton absorber with DOI resolving capability without compromising energy performance. Two groups of lutetium yttrium oxyorthosilicate (LYSO) with dimensions of 1.8 × 1.8 × 50 mm〈sup〉3〈/sup〉 and 1.8 × 1.8 × 20 mm〈sup〉3〈/sup〉 LYSO arrays, and each with four different surface treatments (combining crystal surface finishing and type of reflector coverage), were constructed for the study. The DOI detector utilized the dual-ended readout of pixelated scintillator arrays for depth encoding. The results revealed that the influences of type of the reflector coverage and crystal surface roughness on the performance of the DOI detectors for the 50- and 20-mm-thick LYSO differed greatly. Moreover, the combined use of the proposed partial inter-crystal reflector coverage and the unpolished surface finishing on the 50-mm-thick crystals were shown to improve the DOI resolution without compromising the energy performance but degraded the flood map quality. These results provide useful guidance for selecting an applicable Compton DOI absorber design for developing a high-performance PGCI system.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Ulf Jakob F. Aarsnes, Nathan van de Wouw〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present paper studies the effect of an axial elastic tool (known as a shock sub), mounted downhole in the drill-string, on the occurrence of axial and torsional self-excited vibrations. In particular, we evaluate the feasibility of stabilizing the axial dynamics, dominated by a bilateral (feedback) coupling between the bit-rock interaction and the drill-string wave-equations, through the insertion of a passive down-hole tool. We consider the problem of unwanted drill-string vibrations and explain how these vibrations relate to the so-called axial instability using a distributed parameter (infinite dimensional) model. The equations describing the feedback system causing this instability are derived and then extended to accommodate for the inclusion of the effect of the shock sub. Conditions for the design parameters of the shock sub needed to avoid axial instability are then derived and their practical feasibility are considered.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): S. Mohammadi, M. Papa, E. Pereyra, C. Sarica〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mechanistic modeling is one of the most popular approaches for the prediction of flow pattern, pressure gradient and liquid holdup in multiphase flow problems. Mechanistic models utilize the mass and momentum conservative equations in combination with a set of closure relationships. These closures, which are developed based on specific experimental setups, considerably affect the performance of the mechanistic models. Moreover, new closure relationships continue to be developed to improve the current mechanistic models. Thus, there is a need for a tool that allows the selection of a set of closure relationships for a given set of conditions. In this direction, this paper presents a methodology that relies on a genetic algorithm to search and select a set of closure relationships for a given experimental (field data) that minimize the error between measured and predicted pressure gradient. The results show the applying the genetic algorithm can improve the performance of the mechanistic model by about 277% when compared to selections of closure relationships made by a subject matter expert for the given data set.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Geosciences, Volume 132〈/p〉 〈p〉Author(s): Hongxing Zhang, Mingliang Zhang, Yongpeng Ji, Yini Wang, Tianping Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Vegetation exerts a significant damping effect on tsunami wave run-up on coastal beaches, thus effectively mitigating the tsunami hazard. A depth-integrated two-dimensional numerical model (HydroSed2D, Liu et al., 2008; Liu et al., 2010) is developed to investigate tsunami wave run-up and land inundation on coastal beaches covered with 〈em〉Pandanus odoratissimus〈/em〉 (〈em〉P. odoratissimus〈/em〉). The present model is based on a finite volume Roe-type scheme, that solves the non-linear shallow water equations with the capacity of treating the wet or dry boundary at the wave front. The momentum equations in this model are modified by adding a drag force term, thus considering the resistance effects of vegetation on tsunami waves. The accuracy of the numerical scheme and the vegetation drag force are validated by three experimental cases of dam-break flow propagation in a dry channel, solitary wave propagation in a vegetated flume, and tsunami run-up over an uneven bed. Subsequently, a numerical model is applied to simulate tsunami run-up and land inundation on actual-scale vegetated beaches and a series of sensitive analyses are conducted by comparing numerical results. The obtained numerical results suggest that 〈em〉P. odoratissimus〈/em〉 can effectively attenuate tsunami run-up and land inundation distance on coastal beaches, and a higher attenuation rate for tsunami wave can be achieved by increasing both vegetation width and vegetation density. The tsunami wave height is also an important factor that impacts the tsunami wave run-up and land inundation on vegetated beaches.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July–December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 SoftwareX, Volume 10〈/p〉 〈p〉Author(s): R.D. Martin, Q. Cai, T. Garrow, C. Kapahi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉QExpy is an open source python-3 module that was developed in order to simplify the analysis of data in undergraduate physics laboratories. Through the use of this module, students can focus their time on understanding the science and the data from their experiments, rather than on processing their data. In particular, the module allows users to easily propagate uncertainties from measured quantities using a variety of techniques (derivatives, Monte Carlo), as well as to plot and fit functions to data. The interface is designed to be pedagogical so that students with no prior programming experience can be eased into using python in their introductory physics laboratories.〈/p〉〈/div〉

Description: 〈p〉Publication date: July–December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 SoftwareX, Volume 10〈/p〉 〈p〉Author(s): Simon Behrendt, Thomas Dimpfl, Franziska J. Peter, David J. Zimmermann〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper shows how to quantify and test for the information flow between two time series with Shannon transfer entropy and Rényi transfer entropy using the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" altimg="si1.svg"〉〈mi〉R〈/mi〉〈/math〉 package 〈em〉RTransferEntropy〈/em〉. We discuss the methodology, the bias correction applied to calculate effective transfer entropy and outline how to conduct statistical inference. Furthermore, we describe the package in detail and demonstrate its functionality by means of several simulated processes and present an application to financial time series.〈/p〉〈/div〉

Description: 〈p〉Publication date: July–December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 SoftwareX, Volume 10〈/p〉 〈p〉Author(s): Jacob L. Moore, Nathaniel R. Morgan, Mark F. Horstemeyer〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We discuss the creation and implementation of a generalized library, named ELEMENTS, of mathematical functions for supporting a very broad range of element types including: linear, quadratic, and cubic serendipity elements in 2D and 3D; high-order spectral elements; and a linear 4D element. The ELEMENTS library can be used for research and development of both continuous and discontinuous finite element methods for solving a diverse range of partial differential equations. The library has functions for calculating quantities that are commonly used in finite element methods such as the gradient of a basis function, the Jacobi matrix, the inverse Jacobi matrix, the determinant of the Jacobi matrix, and a physical position inside the element, to name a few examples. The library also supports both Gauss–Legendre and Gauss–Lobatto quadrature rules up to 8 quadrature points in each coordinate direction. The examples and discussions in this paper will focus on Lagrangian solid mechanics and dynamics, but ELEMENTS can be used for many other applications.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biomass and Bioenergy, Volume 127〈/p〉 〈p〉Author(s): Yunna Wu, Yudong Yan, Shiman Wang, Fangtong Liu, Chuanbo Xu, Ting Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Location decision of agroforestry biomass cogeneration (AFBC) project belongs to macro site selection, which is an important task in the pre-project planning stage and directly affects the subsequent economic benefits of the project. However, there are few studies on the site selection of biomass cogeneration projects. And the existing research equates the site selection of biomass cogeneration projects with that of biomass power generation projects, without distinguishing between the two, which is unreasonable. Therefore, in order to solve the above problems, this paper proposes a location decision framework for the AFBC project based on multi-attribute decision-making (MADM) method. Firstly, a special evaluation criteria system is constructed for the location decision of the AFBC project, which includes three main criteria consisting of social needs, resource supply and economic factors, as well as 11 sub-criteria. Then, considering the strong independence of the criteria in the AFBC project location decision, the subjective and objective weights are determined by best-worst method (BWM) and entropy method respectively. And then multiplicative integration method is applied to calculate the comprehensive weights of the criteria to ensure the rationality. Afterwards, Multi-Attributive Border Approximation area Comparison (MABAC) method is used to rank alternative locations and select the optimal. Finally, a case from Hebei Province of China is illustrated to verify the feasibility and validity of this location decision framework in practical applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Enzyme and Microbial Technology, Volume 130〈/p〉 〈p〉Author(s): Fernanda Valadares, Thiago A Gonçalves, André Damasio, Adriane MF Milagres, Fabio M Squina, Fernando Segato, André Ferraz〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Secretome evaluations of lignocellulose-decay basidiomycetes can reveal new enzymes in selected fungal species that degrade specific substrates. Proteins discovered in such studies can support biorefinery development. Brown-rot (〈em〉Gloeophyllum trabeum〈/em〉) and white-rot (〈em〉Pleurotus ostreatus〈/em〉) fungi growing in sugarcane bagasse solid-state cultures produced 119 and 63 different extracellular proteins, respectively. Several of the identified enzymes are suitable for 〈em〉in vitro〈/em〉 biomass conversion, including a range of cellulases (endoglucanases, cellobiohydrolases and β-glucosidases), hemicellulases (endoxylanases, α-arabinofuranosidases, α-glucuronidases and acetylxylan esterases) and carbohydrate-active auxiliary proteins, such as AA9 lytic polysaccharide monooxygenase, AA1 laccase and AA2 versatile peroxidase. Extracellular oxalate decarboxylase was also detected in both fungal species, exclusively in media containing sugarcane bagasse. Interestingly, intracellular AA6 quinone oxidoreductases were also exclusively produced under sugarcane bagasse induction in both fungi. These enzymes promote quinone redox cycling, which is used to produce Fenton’s reagents by lignocellulose-decay fungi. Hitherto undiscovered hypothetical proteins that are predicted in lignocellulose-decay fungi genomes appeared in high relative abundance in the cultures containing sugarcane bagasse, which suggests undisclosed, new biochemical mechanisms that are used by lignocellulose-decay fungi to degrade sugarcane biomass. In general, lignocellulose-decay fungi produce a number of canonical hydrolases, as well as some newly observed enzymes, that are suitable for 〈em〉in vitro〈/em〉 biomass digestion in a biorefinery context.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Computational Physics, Volume 396〈/p〉 〈p〉Author(s): Luigi Brugnano, Juan I. Montijano, Luis Rández〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper we study arbitrarily high-order energy-conserving methods for simulating the dynamics of a charged particle. They are derived and studied within the framework of 〈em〉Line Integral Methods (LIMs)〈/em〉, previously used for defining 〈em〉Hamiltonian Boundary Value Methods (HBVMs)〈/em〉, a class of energy-conserving Runge-Kutta methods for Hamiltonian problems. A complete analysis of the new methods is provided, which is confirmed by a few numerical tests.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 AEU - International Journal of Electronics and Communications, Volume 108〈/p〉 〈p〉Author(s): Hongbo Cao, Faqiang Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, a new current-controlled memristor is proposed and its characteristics are analyzed. Based on this new memristor, a new four-dimensional chaotic circuit is proposed. The complex dynamics of the proposed chaotic circuit are investigated. From the results of the theoretical analysis and the numerical simulations, it is found that the memristor-based chaotic circuit can generate different types of attractors including single-scroll, double-scroll, and periodic attractors for varying circuit parameters. By taking symmetrical initial conditions, symmetric steady coexisting attractors are obtained under the same set of circuit parameters. For certain initial conditions, striking transient coexisting attractors with different timescales can be obtained. In particular, there are two transient changes occurring successively at different time scales respect to the same initial conditions for the proposed chaotic circuit, which is a novel dynamic property. Finally, a practical circuit platform that describes the proposed chaotic circuit on Field Programmable Gate Arrays (FPGA) is designed, and some experimental results are presented for confirmation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 AEU - International Journal of Electronics and Communications, Volume 109〈/p〉 〈p〉Author(s): Negar Daryanavardan, Mostafa Derakhtian, Mohammad Neinavaie, Saeed Gazor〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents a new low complexity sphere decoding (SD) for the generalized spatial modulation (GSM). We introduce a pre-processing stage using the lattice reduction (LR) aided minimum mean squared error (MMSE) equalization in the GSM systems. This stage speeds up the search in the decoding tree and provides a lattice dependent (LD) initial choice of the radius. Moreover, we derive a lattice independent (LI) initial radius that guarantees the optimal performance at a high signal-to-noise ratio (SNR). We also propose an iterative method to increase the radius in order to achieve the maximum likelihood (ML) performance at all SNRs. We show that the proposed algorithm achieves the ML performance while requiring prominently less computational complexity (CC) than an exhaustive search. In addition, we analyze the CC of the resulting algorithm at high SNRs and we derive an analytical expression for the complexity. The simulation results demonstrate a noticeable decrease in the CC of the proposed sphere decoding algorithm in comparison with its counterparts, particularly at low SNRs.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 AEU - International Journal of Electronics and Communications, Volume 109〈/p〉 〈p〉Author(s): Nazir Hatami, Javad Nourinia, Changiz Ghobadi, Maryam Majidzadeh, Burhan Azarm〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A multiple-input-multiple-output (MIMO) wireless local area network (WLAN) band-notched antenna with high inter-element isolation is proposed. The proposed MIMO system is composed of two monopole antennas, each composed of a slotted radiating patch and a stepped ground plane. The embedded slots and the ground plane steps are wisely located to achieve the desired wide band functionality as well as WLAN band-notched realization. The overall size of the MIMO antenna is 20 × 34 mm〈sup〉2〈/sup〉 printed on 1.6 mm FR4 substrate. Moreover, to reduce the coupling between the constituent monopole antennas and enhance the isolation, a parasitic element is embedded between the antennas on the substrate backside. By wise tuning of the position and dimensions of the parasitic element, high isolation is achieved which is necessary for MIMO communication systems. Both simulation and measured results confirm a 10-dB impedance bandwidth of 2.6–11.2 GHz excluding the rejected band for |S〈sub〉11〈/sub〉| ≤ −10 dB, and |S〈sub〉21〈/sub〉| ≤ −20 dB. Wide bandwidth, small size, and band-notched feature are some of the merits of the proposed MIMO antenna. Detailed analysis on the antenna performance are released in detail throughout the paper.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Nohora Caicedo, Renaud Leturcq, Jean-Pierre Raskin, Denis Flandre, Damien Lenoble〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Metal-oxide nanowires are showing a great interest in the domain of gas sensing due to their large response even at a low temperature, enabling low-power gas sensors. However their response is still not fully understood, and mainly restricted to the linear response regime, which limits the design of appropriate sensors for specific applications. Here we analyse the non-linear response of a sensor based on ZnO nanowires network, both as a function of the device geometry and as a response to oxygen exposure. Using an appropriate model, we disentangle the contribution of the nanowire resistance and of the junctions between nanowires in the network. The applied model shows a very good consistency with the experimental data, allowing us to demonstrate that the response to oxygen at room temperature is dominated by the barrier potential at low bias voltage, and that the nanowire resistance starts to play a role at higher bias voltage. This analysis allows us to find the appropriate device geometry and working point in order to optimize the sensitivity. Such analysis is important for providing design rules, not only for sensing devices, but also for applications in electronics and opto-electronics using nanostructures networks with different materials and geometries.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Gang Xu, Chen Cheng, Wei Yuan, Zhaoyang Liu, Lihang Zhu, Xintong Li, Yanli Lu, Zetao Chen, Jinglong Liu, Zheng Cui, Jingjing Liu, Hong Men, Qingjun Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Last decade has seen a growing trend toward smartphone-based biochemical sensing systems. Meanwhile, flexible electrochemical sensing devices like wristbands, patches, and tattoos have been widely developed for 〈em〉in situ〈/em〉 detections of analytes in accessible biofluids. For these devices, the connectivity with smartphone and the flexibility of the whole device are hard to achieve at the same time, due to the need for rigid batteries or wired connections. Here, a smartphone-based battery-free and flexible electrochemical patch is developed for real-time calcium and chloride ions detections in various biofluids. The patch is integrated with near field communication (NFC) module, on-site signal processing circuitry, and an all-printed stretchable electrode array which can maintain stable conductivity during stretching, without the need for serpentine designs. The device enables wireless power harvesting, on-site signal processing, and wireless data transmission capabilities. NFC-enabled smartphones can wirelessly power the patch and get the detection results through inductive coupling between antennas. The calcium and chloride sensors showed good sensitivity, repeatability, selectivity, and stability in quantitative detections of target ions. 〈em〉Ex situ〈/em〉 measurements in serum, urine, tear, and sweat demonstrated good consistency with specialized instrument. Real-time on-body sweat analysis with the patch was also performed, which further indicated the usability and stability of the device in wearable applications. This platform provides a battery-free, wireless, and flexible solution for smartphone-based electrochemical sensing systems, which can be applied to rapid analysis of various biofluids.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092540051930944X-ga1.jpg" width="354" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Shuangming Wang, Jing Cao, Wen Cui, Longlong Fan, Xifei Li, Dejun Li, Tong Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉One dimensional porous Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 rectangular microrods (MR) are designed and successfully prepared by a distinctive electrospun precursor-hydrothermal regulation-annealing treatment strategy while Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanofibers (NF) are also synthesized for comparison by directly calcining precursors without hydrothermal treatment. The hydrothermal treatment before annealing process results in morphology and structure transition of Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 products from compact solid nanofibers to porous rods. When applied as a gas sensing material, Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 porous rods based sensors exhibit enhanced gas sensing properties in terms of rapid response time (3 s), recovery time (5 s), good selectivity and stability towards 100 ppm acetone gas at a relatively low working temperature of 200 °C. Meanwhile, the response of Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 porous rods toward 100 ppm acetone reaches approximately 5 times higher than that of solid Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanofibers. The enhanced acetone gas sensing properties of Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 rectangular porous rods are believed to originate from its porous structure and large surface area, facilitating gas adsorption and surface reaction and causing significant change in the thickness of holes accumulation layer (HAL). Feasible morphology-adjusting strategy and enhanced acetone gas sensing performances further highlight the advantage of as-prepared Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 porous rods in future acetone real-time monitoring.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Chinedu I. Ossai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To advance the prognosis of progressing cavity Pumps (PCPs) used for artificial lifting, the pump-off need to be identified to forestall failure. This study developed a new technique for determining the Pump-off events Activation Times (PATs) of the PCPs using the transient Water Discharge Rates (WDRs) from coal seam gas producing wells. The Gaussian distribution function parameters of the rolling standard deviations of the water discharge rate (RSWR) and the transition probability of the rolling standard deviations of the water discharge rate (TP_RSWR) were used to build the model. By determining the anomalies in the RSWR signals with the bottom-up segmentation technique and computing the statistical characteristics at the changepoint locations, the steady-state of the WDR signals was established. This steady-state signal, which represents the Operation Transition Level (OTL) between the Normal Operation (NOP) and the Pump-off Event (POE) was used for monitoring the transition of the PCPs' operating status. An algorithm was developed in Python and tested it on field data from 36 coal seam gas wells. The performance of my technique was determined with precision, recall and F1 score, which gave an average value of 94.94%, 92.63%, and 93.56% respectively. It is expected that the implementation of this technique in the real-time estimation of PATs will be vital for reducing PCPs faults seeing that poor PATs detection results in PCPs running dry and consequently failures due to the extreme temperatures and abrasions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Xiuyu Wang, Heng Li, Xuantong Zhu, Mengzhen Xia, Tao Tao, Binxin Leng, Wen Xu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A kind of ZnSn(OH)〈sub〉6〈/sub〉 crystalline precursor composed of micro- and nano-sized particles with two different morphologies was synthesized by co-precipitation method with the presence of triethanolamine (TEOA) as functional reagent. Zn〈sub〉1-〈/sub〉〈em〉〈sub〉x〈/sub〉〈/em〉Mg〈em〉〈sub〉x〈/sub〉〈/em〉Sn(OH)〈sub〉6〈/sub〉 samples (0≤〈em〉x〈/em〉≤0.5) were prepared by doping Mg〈sup〉2+〈/sup〉 ions in the synthesis process of ZnSn(OH)〈sub〉6〈/sub〉 precursor. Experimental results reveal that both the morphology and size of ZnSn(OH)〈sub〉6〈/sub〉 particles can be changed by TEOA and Mg〈sup〉2+〈/sup〉 ions, but not changed by dehydration at high temperature with the formation of Zn〈sub〉1-〈/sub〉〈em〉〈sub〉x〈/sub〉〈/em〉Mg〈em〉〈sub〉x〈/sub〉〈/em〉SnO〈sub〉3〈/sub〉 samples. When 〈em〉x〈/em〉 is 0.1, the effect of Mg〈sup〉2+〈/sup〉 ions on the morphology and size of ZnSn(OH)〈sub〉6〈/sub〉 particles is not remarkable, but the ethanol sensitivity of the resulting ZnSnO〈sub〉3〈/sub〉 sample at a low temperature of 80 °C is significantly improved by Mg〈sup〉2+〈/sup〉 ions at the conditions of nano-TiO〈sub〉2〈/sub〉 decoration and UV radiation. The ethanol response of the composite sample (ZM〈sub〉0.1〈/sub〉SO–T〈sub〉10〈/sub〉) is as high as ca. 149 at 500 ppm concentration, and its corresponding response and recovery time is about 4 s and 80 s, respectively. Furthermore, the sensor with ZM〈sub〉0.1〈/sub〉SO–T〈sub〉10〈/sub〉 also shows a good selectivity and long-term stability. Possible reasons for the superior ethanol sensitivity at low temperature were discussed.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉*Here ZnSnO〈sub〉3〈/sub〉 without Mg doping and Zn〈sub〉0.9〈/sub〉Mg〈sub〉0.1〈/sub〉SnO〈sub〉3〈/sub〉 with10% TiO〈sub〉2〈/sub〉 decoration samples prepared by this study are denoted as ZM〈sub〉0〈/sub〉SO and ZM0.1SO, respectively.〈/p〉 〈p〉In this study ZnSn(OH)〈sub〉6〈/sub〉 crystalline precursor composed of micro- and nano-sized particles with two different morphologies in (a) was synthesized by the control of the amount of triethanolamine (TEOA) as functional additive based on co-precipitation method. The −OH groups in TEOA can make ZnSn(OH)〈sub〉6〈/sub〉 cubic crystal nuclei adsorbed and connected together, resulting in the formation of a micro-sized cluster with cubic corners exposed (a). Usually, the cubic corners are corroded in the etching process [46], but those cubic corners of the micro-sized clusters in (a) are not corroded when nano-sized particles exist with them. However, Mg〈sup〉2+〈/sup〉 ions used for substitute for Zn〈sup〉2+〈/sup〉 ions by doping can counteract the role of TEOA in the synthesis of ZnSn(OH)〈sub〉6〈/sub〉 precursor. The cubic corners of the micro-sized clusters in (a) begin to be corroded when ZnSn(OH)〈sub〉6〈/sub〉 precursor is synthesized with the presence of a small number of Mg2+ ions (b), and no micro-sized clusters are formed if there are more Mg2+ ions in the synthesizing process. After dehydration of Zn〈sub〉1-〈/sub〉〈em〉〈sub〉x〈/sub〉〈/em〉Mg〈em〉〈sub〉x〈/sub〉〈/em〉Sn(OH)〈sub〉6〈/sub〉 precursor at high temperature, Zn〈sub〉1-〈/sub〉〈em〉〈sub〉x〈/sub〉〈/em〉Mg〈em〉〈sub〉x〈/sub〉〈/em〉SnO〈sub〉3〈/sub〉 was formed.〈/p〉 〈p〉Gas-sensing test reveals the following results: (1) The ZnSnO〈sub〉3〈/sub〉 (ZM〈sub〉0〈/sub〉SO) and Zn〈sub〉0.9〈/sub〉Mg〈sub〉0.1〈/sub〉SnO3 (ZM〈sub〉0.1〈/sub〉SO) samples, originating from the dehydration of samples in (a) and (b), respectively, have a high response to ethanol at a high temperature of 220 °C. The gas-sensing activity of ZnSnO〈sub〉3〈/sub〉 is greatly enhanced by Mg〈sup〉2+〈/sup〉 doping, as can be inferred from the gas response value of the two samples. (2) When nano-TiO〈sub〉2〈/sub〉 was used to decorate ZM〈sub〉0.1〈/sub〉SO, the resulting sensor under UV irradiation has a low operating temperature at a maximum gas response of 149, which is far more than that of our previous study [46].〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519309463-ga1.jpg" width="126" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Peng Lei, Ying Zhou, Ruiqi Zhu, Yang Liu, Chuan Dong, Shaomin Shuang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Iron phthalocyanine (FePc) functionalized nitrogen, boron–doped reduced graphene oxide (N,B–rGO) nanocomposite (FePc/N,B–rGO) was facilely fabricated for the first time as a electrochemical platform for sensitive detection of glutathione (GSH). FePc was immobilized on N,B–rGO substrate through π–π interaction, and N,B–rGO provided FePc with a large specific surface area to improve electron transfer and maintain its electrocatalytic activity. Cyclic voltammetric measurements showed that FePc and N,B–rGO triggered the synergistic effect and exhibited a satisfactory electrocatalytic activity. By integration of FePc and N,B–rGO, the FePc/N,B–rGO/GCE sensor displayed a wide linear dynamic range from 5.0 × 10〈sup〉–8〈/sup〉 M to 1.6 × 10〈sup〉–3〈/sup〉 M with a low detection limit of 7.1 × 10〈sup〉–9〈/sup〉 M. Besides, the electrochemical sensor presented satisfiable reproducibility, excellent anti–interference performance and long–term stability. The method was further expanded to determinate GSH in human serum sample with the recoveries between 95.0–109.0%.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519309578-ga1.jpg" width="378" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Soner Çakar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, a novel 1–10 phenanthroline and 1–10 phenanthroline 5,6 diol based metal complex sensitizers for dyes sensitized solar cells applications is investigated. The 1–10 phenanthroline 5,6 diol structure is formed by the addition of two –OH groups to 1–10 phenanthroline, which has higher cell yields due to binding sites of TiO〈sub〉2〈/sub〉. The 1–10 phenanthroline 5,6 diol metal complexes are prepared with Cu and Fe at different pH values. Additionally, these metal complexes are mixed at different ratio to prepare cocktail dyes. The maximum cell efficiency value of dyes sensitized solar cells based on 1–10 phenanthroline 5,6 diol prepared with Cu:Fe 2:1 ratio cocktail dyes is 3.70%. The phen-ol based DSSC containing Cu-complex dye exhibits 2.80% conversion efficiency value, which shows an 25% lower than cocktail phen-ol based dyes sensitized solar cells. The solar cell efficiency values are demonstrated decrement by increasing of Fe-complex ratio. However, the Fe-complexes exhibit more stable complex structures than Cu-complexes. This phenomenon also gives a new way to the use of the environmentally friendly metal complex-based dyes sensitized solar cells. Additionally, these transition metal-based sensitizers will be an alternative to synthetic organic dyes and noble metal-based solar cells.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Desalination, Volume 467〈/p〉 〈p〉Author(s): Hyunkyung Lee, Jihun Lim, Min Zhan, Seungkwan Hong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Preoxidation is gaining spotlight in the mitigation of ultrafiltration (UF) membrane fouling caused by algal organic matter (AOM). Although it is known to be beneficial in freshwater, its applicability in seawater treatment has barely been explored. This study first evaluated the effect of UV/permonosulfate (PMS) oxidation for UF process against marine harmful algal blooms (HAB). The transition of AOM released from 〈em〉Pseudo Nitzchia〈/em〉 was investigated which produces a neurotoxin, domoic acid (DA). Specifically, UV light emitting diodes (LED) were employed as UV source. The results indicated UV-LED/PMS treatment effectively reduces the fouling potential of AOM. However, the participation of abundant chloride ions generated free chlorine and disinfection byproducts, thus, PMS addition below 0.5 mM was suggested for seawater applications. With respect to PMS 0.5 mM, TOC and cake layer resistance were reduced by 10% and 85%, respectively, and this was followed by significant improvements in water permeability, flux reversibility and permeate quality of UF process. Furthermore, PMS exhibited significant reactivity for decomposing DA achieving rapid disappearance of 1 ppm of DA within a minute. The aforementioned results encourage the use of PMS as a bulk oxidant in seawater treatment to simultaneously mitigate membrane fouling and improve permeate quality.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0011916418325608-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Geosciences, Volume 131〈/p〉 〈p〉Author(s): Ludovic Räss, Dmitriy Kolyukhin, Alexander Minakov〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present an efficient implementation of the method for sampling spatial realisations of a 3-D random fields with given power spectrum. The method allows for a multi-scale resolution and approaches well for parallel implementations, overcoming the physical limitation of computer memory when dealing with large 3-D problems. We implement the random field generator to execute on graphical processing units (GPU) using the CUDA C programming language. We compare the memory footprint and the wall-time of our implementation to FFT-based solutions. We illustrate the efficiency of the proposed numerical method using examples of an acoustic scattering problem which can be encountered both in controlled-source and earthquake seismology. In particular, we apply our method to study the scattering of seismic waves in 3-D anisotropic random media with a particular focus on P-wave coda observations and seismic monitoring of hydrocarbon reservoirs.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Geosciences, Volume 131〈/p〉 〈p〉Author(s): R. Moreno, F.J. Pérez-Gil, J.J. Pardo, A. Navarro, F.J. Tapiador〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Current computing platforms, including HPC, Grid and Cloud computing, offer many computational resources. These platforms can provide the scientific world with on-demand and scalable computing power. However, their use requires advanced computer skills. In our work, we summarize the main problems found by research scientists when they attempt to execute complex software on one or several of these platforms. As a solution to these problems, we propose the 〈em〉Science for Everyone〈/em〉 (ScifE) framework, and an intuitive and easy-to-use web interface, to perform scientific experiments on HPC or Cloud platforms. The Community Earth System Model (CESM) has been used to test our proof-of-concept framework as it is a complex scientific software used by many climate researchers. Using our framework, a user can execute CESM with custom parameters with only a few clicks on the web interface. As ScifE is generic, other software can be imported relatively easy to our framework. Additional collaborative tools are being developed for successive versions of ScifE, enhancing the practice of science.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Bradley Ledden, Joe Bruton〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We developed a ring electrode sensor for down-stream electrochemical sensing of microfluidic ELISA assay. The sensor is designed to easily integrate into the flow environment. Noble metal inks on Low Temperature Co-fired Ceramic provide straight forward fabrication at the mesoscale yielding robust sensors with very low sensing volumes. Two different sensor geometries were modeled. The best design was fabricated and tested in both static and flowing solutions. The sensor exhibits both macroelectrode and microelectrode behavior depending on fluid flow rate. Sensors of this type may be ideal for applications where electrochemical detection is desired in a flowing solution since the ring electrode has low propensity for bubble trapping.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Nada F. Atta, Ahmed Galal, Yousef M. Ahmed, Ekram H. El-Ads〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Cardiovascular disease is a class of diseases that involves the heart or blood vessels. It includes coronary artery diseases such as angina and myocardial infarction. In addition, hypertension is quantitatively the most important risk factor for premature cardiovascular disease. Dobutamine (DB) and amlodipine (AM) are medications commonly used for treating these diseases. Therefore, simultaneous determination of these drugs in presence of interfering compounds in biological fluids; paracetamol (PA), and ascorbic acid (AA) is essential for patients under medical treatment by these drugs. An innovative strategy is introduced for fabrication of a novel layered composite based on layer-by-layer modification of a glassy carbon electrode surface (GC) with multi-walled carbon nanotubes (CNT), ionic liquid crystal (ILC), graphene (RGO) and 18-Crown-6 (CW); (GC/CNT/ILC/RGO/CW). The layered sensor exhibited excellent electro-catalytic activity for determination of AA in the drugs mixture and simultaneous determination of DB, PA, and AM in human serum in linear dynamic ranges; 0.4 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mo〉→〈/mo〉〈/math〉 40 μM, 0.02 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mo〉→〈/mo〉〈/math〉 40 μM, 0.001 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mo〉→〈/mo〉〈/math〉 20 μM and 0.008 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mtext〉 〈/mtext〉〈mo〉→〈/mo〉〈/math〉 30 μM with low detection limit values; 9.24 nM, 0.497 nM, 0.0906 nM and 0.139 nM, respectively and low quantification limit values; 30.8 nM, 1.66 nM, 0.302 nM and 0.463 nM, respectively. Further practical application was performed for quantitative analysis of AA, DB, PA and AM in their pharmaceutical formulations.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519308482-ga1.jpg" width="392" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Fuwei Yu, Hanqiao Jiang, Fei Xu, Zhen Fan, Hang Su, Junjian Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, a new fabrication method was reported for establishment of a 2.5D reservoir micromodel, which incorporated 3D geometry of porous media and visualization of 2D microfluidic chips. Flow physics such as imbibition, rison and rheon were visualized in the new 2.5D reservoir micromodel through water flooding experiments in water-wet and oil-wet 2.5D reservoir micromodels. Corresponding results demonstrated the strong capacity of the presented 2.5D reservoir micromodel to mimic the real 3D porous media. Besides, four theoretical patterns concerning residual oil distributions were obtained based on water flooding, surfactant flooding and polymer flooding experiments. Furthermore, imbibition of a Winsor I type surfactant system was investigated, accompanied by explanation and visualization of two major enhanced oil recovery (EOR) mechanisms, namely microemulsion imbibition and residual oil solubilization, which confirmed the assumptions made based on core imbibition experiments.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Mohamed R. Shalaby, Liyana Nadiah Osli, Stavros Kalaitzidis, Md Aminul Islam〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Thermal maturity and palaeodepositional environment of the Taratu Formation has been studied by evaluating its geochemical properties and organic petrographical features. Geochemical properties of the Cretaceous-Palaeocene Taratu source rock that are identified through pyrolysis indicate that this formation has excellent organic matter quality, quantity and hydrocarbon generation potential. Only the Cretaceous-aged sequence from this formation is thermally mature, with Tmax values ranging from 429 °C to 459 °C, while Palaeocene samples are found to be thermally immature. Organic matter of the Taratu Formation comprises primarily of oil and gas prone kerogen type II-III and gas prone kerogen type III, which is reflected by high HI (165.0–327.5 mg HC/g TOC) and low OI (5.00–25.7 mg CO2/g TOC) values. Tissue Preservation Index (TPI) and Gelification Index (GI) indicates that the Taratu Formation was previously deposited in a limnic environment. Further assessment of the source rock's palaeodepositional environment through correlating cross-plots of various biomarker data and evaluation of organic petrography suggests that the formation was subjected to brackish water influx.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 180〈/p〉 〈p〉Author(s): Zulong Zhao, Yu Shi, Daoyong Yang, Na Jia〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel and pragmatic technique has been developed and validated to quantify gas exsolution of alkane solvent(s)–CO〈sub〉2〈/sub〉–heavy oil systems with consideration of interface mass transfer for each gas component under nonequilibrium conditions. Experimentally, constant composition expansion (CCE) tests of three alkane solvent(s)–CO〈sub〉2〈/sub〉–heavy oil systems are conducted with a visualized PVT cell under equilibrium and nonequilibrium conditions. The liquid height and pressure of the system are continuously monitored and recorded during experiments to measure, respectively, the bubblepoint pressure, pseudo-bubblepoint pressure, and the entrained gas volume. With the assumption of instantaneous nucleation, a mathematical model which integrates Peng-Robinson equation of state (PR EOS), Fick's second law, and nonequilibrium boundary condition has been developed to quantify not only the amount of the evolved gas and entrained gas, but also the dynamic composition of gas phase as a function of time. Once the deviations between the measured gas volumes and the calculated ones have been minimized, the mass transfer Biot number, individual diffusion coefficient, and interface mass transfer coefficient of each gas component as well as the gas bubble number are determined. Increases in experimental temperature and pressure are found to impose opposite effects on diffusion coefficient during gas exsolution processes. The diffusion of each gas component is found to be faster when the temperature becomes higher or the initial pressure becomes lower. Either CO〈sub〉2〈/sub〉 or C〈sub〉3〈/sub〉H〈sub〉8〈/sub〉 diffuses faster than CH〈sub〉4〈/sub〉 in the liquid phase under the same condition. In addition, the interface mass transfer coefficients, with an order of CO〈sub〉2〈/sub〉 〉 CH〈sub〉4〈/sub〉 〉 C〈sub〉3〈/sub〉H〈sub〉8〈/sub〉, obtained in this study are much higher than those collected in the literature since the nonequilibrium conditions greatly facilitate gas exsolution. The determined mass transfer Biot numbers in this study are large, indicating that the bulk resistance due to molecular diffusion inside the heavy oil dominates the gas exsolution process compared to the interfacial resistance.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Jingdong Liu, Tao Liu, Youlu Jiang, Tao Wan, Ruining Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The distribution, origin, and evolution of overpressure in the petroliferous basin are important problems that need to be addressed for oil and gas exploration. The distribution and origin of overpressure in the Shahejie Formation in the northern Dongpu Depression are analyzed based on geological studies, logs, and pressure data. The contribution ratios of different overpressure origins are quantified, and the evolutionary stages of overpressures of different origins are further divided. The results show that the formation pressure coefficients of Shahejie Formation in the Dongpu Depression are mainly within the range of 0.9–1.5. The overpressures are mainly distributed in the Sha-3 and Sha-4 Members of the Haitongji sag, the Central uplift belt and the Qianliyuan sag. From the sag to its surrounding area, the formation pressure coefficient gradually decreases. The high deposition rate and strong hydrocarbon generation are the main causes of overpressure formation in the Shahejie Formation in the Dongpu Depression. Based on the stress–strain characteristics of different origin overpressures and the log response parameters, two models, acoustic travel time-effective vertical stress and electrical resistivity-effective vertical stress, are established to identify and quantify the different origin overpressures. The calculation results for the area from the Haitongji sag and Qianliyuan sag to the Central uplift belt show that the main cause of overpressure gradually changes from both disequilibrium compaction and hydrocarbon generation to disequilibrium compaction as the main factor, with the contribution of disequilibrium compaction to overpressure in the Central uplift belt at about 87%. The Sha-3 Members of the Shahejie Formation in the Haitongji sag and the Qianliyuan sag are more strongly affected by hydrocarbon generation, which accounts for 42% and 47.5% of overpressure origin, respectively. There are five stages in the evolution of overpressure in the Shahejie Formation in the northern Dongpu Depression: normal compaction (before 35 Ma), mixed pressurization (35-27 Ma), uplift and pressure release (27-17 Ma), disequilibrium compaction (17-11 Ma), and secondary mixed pressurization (12 Ma-present).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Zhiwei Zeng, Hongtao Zhu, Lianfu Mei, Jiayuan Du, Hongliu Zeng, Xinming Xu, Xiaoyun Dong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Few studies have focused their attentions on the source-to-sink (S2S) system from a multiple-level perspective. We have proposed an effective multilevel S2S subdivision approach based on the integrated study of seismic geomorphology, well-based facies, seismic facies and multi-attribute. The inspiration of multilevel S2S subdivision method is drawn mainly from the modern Diancang Mountain- Lake Erhai S2S system with different-orders of drainage divides. The Paleogene Central Uplift system during the syn-rift stage in Xijiang Sag, Pearl River Mouth Basin, South China Sea, provides a suitable example to test the approach and analyze the multilevel S2S characteristics of an ancient uplift system. The result shows that the Central Uplift system can be divided into three second-level sub-S2S systems (R-A, R-B and R-C), and can be further sub-divided into twelve third-level sub-S2S systems (A1∼A5, B1∼B5 and C1∼C2). Generally, the A1∼A5 and B1∼B4 systems are developed at the gentle slopes and deposited a series of narrow-shaped braided deltas with higher exploration potential, whereas the B5 and C1∼C2 systems are developed at the relatively steep slopes and deposited a series of lobate shaped turbidite and fan deltas with lower reservoir quality. Based on the multilevel S2S analysis, the ancient uplift can be scientifically sub-divided and compared with each sub-S2S system, including the sediment-transport type and distance, sedimentary facies characteristics and stacking relationship with the hydrocarbon source rocks. These in-depth and detailed studies have practical significance for the exploration of favorable reservoir sandbodies and stratigraphic-lithologic traps.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Weiping Diao, Saurabh Saxena, Michael Pecht〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Accelerated cycle life testing of lithium-ion batteries is conducted as a means to assess whether a battery will meet its life cycle requirements. This paper presents a study to identify optimal accelerated cycle testing conditions for LiCoO〈sub〉2〈/sub〉-graphite cells. A full factorial design of experiment with three stress factors—ambient temperature (10 °C, 25 °C, 45 °C, 60 °C), discharge current rate (C-rate, 0.7C, 1C, 2C), and charge cut-off C-rate (C/5, C/40)—is used to study the effects of these stress factors on battery capacity fade and to obtain the data necessary for decision making. An empirical accelerated degradation model is then developed to capture the characteristics of the two-stage capacity degradation process, along with an accelerated test planning approach.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Linna Dai, Qing Sun, Jianguang Guo, Jun Cheng, Xiaoyan Xu, Huanhuan Guo, Deping Li, Long Chen, Pengchao Si, Jun Lou, Lijie Ci〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Li-O〈sub〉2〈/sub〉 batteries are considered as one of the future candidates for electrochemical power sources due to their high theoretical energy density. As the dominating component affects the performance of Li-O〈sub〉2〈/sub〉 batteries, O〈sub〉2〈/sub〉-cathode catalyst with high efficiency, low price, facile preparation is important. Herein, polyhedral and porous Mn〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 rods are fabricated for cathode catalysts in Li-O〈sub〉2〈/sub〉 batteries via electrospinning method followed by calcination. The Mn〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 catalyst possesses a three-dimensional porous structure, which can offer good catalytic activity, expose plenty of active sites and improve the diffusion of electrolyte and O〈sub〉2〈/sub〉. When employed as the cathode catalyst, the Li-O〈sub〉2〈/sub〉 batteries show enhanced initial discharge capacity of 9701 mA h g〈sup〉−1〈/sup〉 at a current density of 200 mA g〈sup〉−1〈/sup〉, superior rate capacity and good cycling stability within 160 cycles at the capacity of 500 mA h g〈sup〉−1〈/sup〉. These enhanced performances demonstrate a facile method to fabricate Mn〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 with unique structure as a promising catalytic material for Li-O〈sub〉2〈/sub〉 batteries.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Yong Zhang, Guangwu Wen, Shan Fan, Yuanyuan Chu, Shuhua Li, Baoyun Xu, Jing Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, three-dimensional phenolic hydroxyl functionalized partially reduced graphene oxides with high hydroxyl content and significantly enhanced electrochemical performance have been successfully prepared by a one-pot hydrothermal method from graphene oxide dispersions. A very small amount of 4-aminophenol is employed as reducing and N-doping agent, structure modifier and the phenolic hydroxyl source, at the same time. The electrochemical test results show that as binder-free electrode, the as-synthesized sample with high hydroxyl content (6.15 at%) exhibits an ultrahigh specific capacitance of 284.1 F g〈sup〉−1〈/sup〉 at current density of 0.3 A g〈sup〉−1〈/sup〉 in 6 M KOH electrolyte, and retains for 80.4% even at a current density of 10 A g〈sup〉−1〈/sup〉. Above all, the as-assembled symmetric supercapacitor shows superior energy density of 9.9 Wh kg〈sup〉−1〈/sup〉 at a power density of 75.0 W kg〈sup〉−1〈/sup〉. The significantly enhanced electrochemical performance can be ascribed to the high hydroxyl content and other oxygen functional groups, N-doping, modified porous framework and the high specific surface area of the graphene. Those special characteristics suggest that the as-synthesized graphene materials may have potential applications in high performance supercapacitors.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775319307840-fx1.jpg" width="330" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Nabil M. Al-Areeq, Abubakr F. Maky, Ahmed S. Abu-Elata, Mahmud A. Essa, Salem S. Bamumen, Gamal A. Al-Ramisy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Masilah oilfields are rich-oil provinces in the Sayun-Masilah Basin. The petroleum system including essential elements and processes is a very important for understanding and development of oilfield to further explore hydrocarbons in the whole basin. Integrated geochemical, geological, petrological and petrophysical analyses were performed on the source and reservoir rocks in the Masilah oilfields to gives information about the complete petroleum system. The Masilah oilfields filled with syn- and post-rift sediments, including a self-contained source-reservoir system. The geochemical results indicate that the organic-rich shales of the Madbi Formation are considered as oil-source rocks, with high total organic carbon content of more than 5.0 wt% TOC and oil-prone kerogen Types II and I. The Madbi shales are currently characterized by thermally mature level, within the oil generation window. Geochemical biomarker correlations of oil-source rock indicate that there is a genetic link between the oils and the Late Jurassic Madbi shale source rock in the Masilah oilfields. Therefore, the geochemical characteristics of the Madbi source rock have been collaborated into basin models and illustrate that the Madbi source rock had passed the peak-oil generation window during the Late Cretaceous to present-day and that large amounts of oil were generated. The generated oil was expelled and migrated to the overlain Early Cretaceous Qishn clastic reservoir rocks through faults during the Oligocene-Middle Miocene. The oil was then accumulated and trapped into horst and tilted fault blocks that initial formed during the Late Jurassic-Early Cretaceous rifting.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Jeffrey O. Oseh, M.N.A. Mohd Norddin, Issham Ismail, Abdul R. Ismail, Afeez O. Gbadamosi, Augustine Agi, Shadrach O. Ogiriki〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With increasing strict environmental laws, there is a need for operators to design a benign oil-based muds (OBMs). In this study, oil extracted from non-edible sweet almond seed (SASO) was used as the continuous phase to formulate biodiesel-based drilling mud (BBDM). Different properties of the BBDM including the economic viability were evaluated and compared with those of the diesel OBM to determine the applicability of these properties for drilling fluids and their level of toxicity to the environment. The results indicate that the rheology, filtration properties, electrical stability, thermal stability and shale swelling inhibition performance of the BBDM are comparable with those of the diesel OBM. The biodiesel has a significantly higher flash point of 169 °C than the diesel with 78 °C; demonstrating that it can supply better fire safety than the diesel. The data of the toxicity test indicate SASO to be safer and less harmful compared to diesel #2 type used. After the 28-day period of biodegradation tests, the BBDM and the diesel OBM showed 83% and 25.2% aerobic biodegradation with 〈em〉Penicillium〈/em〉 sp., respectively. The low branching degree and absence of aromatic compounds in the BBDM contributes for its higher biodegradation. The economic evaluation of the BBDM indicates low cost of formulation and waste management. The general outcome of the tests illustrates that SASO has the potentials of being one of the technically and environmentally feasible substitutes for the diesel OBM.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Bao Jia, Jyun-Syung Tsau, Reza Barati〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Molecular diffusion is an important EOR mechanism in naturally fractured reservoirs. However, the laboratory-measured diffusion coefficient in the fractured porous media is still limited; and grid sensitivity analysis is missing in the literature when the single-porosity system is applied to history match the pressure decline curve. We aimed to fill the gaps using Radial Constant Volume Diffusion (RCVD) method experimentally to investigate diffusion coefficients at different pressures in hydrocarbon saturated porous media. A special in-house cell is designed to hold the core sample in the center with the annulus around simulating the fracture. The core is initially saturated with oil while the annulus is filled with CO〈sub〉2〈/sub〉 at the same pressure. During the measurements, the system pressure declines as gas diffuses into the oil phase until it reaches chemical equilibrium. The pressure decline curve is history matched to determine the diffusion coefficient. The initial pressure is 597 psi, and the diffusion coefficient is determined in numerical models accordingly. Molecular diffusion coefficients are estimated at different experiment periods to reveal the pressure-dependency. A workflow is proposed to obtain effective diffusion coefficients in dual-porosity models that could be extended to multi-component systems. Besides, flow characteristics in the RCVD system are characterized and capillary pressure effect is investigated in this study.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): R. Farajzadeh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To mitigate the negative impacts of hydrocarbon fuels on climate change complementary decision tools should be considered when selecting or evaluating the performance of a certain production scheme. The exergy analysis can give valuable information on the management of the oil and gas reservoirs. It can also be used to calculate the CO〈sub〉2〈/sub〉 footprint of the different oil recovery mechanisms. We contend that the concept of exergy recovery factor can be used as a powerful sustainability indicator in the production of the hydrocarbon fields. The exergy-zero recovery factor is determined by considering exergy balance of full cycle of hydrocarbon-production systems and defines boundaries beyond which production of hydrocarbons is no longer sustainable. An example of the exergy analysis is presented in the paper.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Ahmad Ghasemi, Hossein Jalalifar, Saeid Norouzi Apourvari, Mohammad Reza Sakebi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Wellbore instability is a big challenge in shale formations. The objective of this study is to investigate the effectiveness of a natural additive as a shale inhibitor. The capability of this additive for reducing ion movement into shale and plugging its pore throats has been tested and compared with salts and nano particles. The ions and water movement into shale and resultant swelling was measured by modified gravimetric, swelling and modified immersion tests. The results showed that using Henna extract could reduce the ion and water movement into shale. In addition, the results of pore pressure tests showed that 3 wt % of Henna extract are more effective than nano particles and could completely plug the pore throats of shale while the mud rheological properties are still maintained. The findings of this study show that the Henna extract could be considered as a cost-effective and an environmentally-friendly shale inhibitor.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0920410519306345-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Anna Slesarenko, Igor K. Yakuschenko, Vahid Ramezankhani, Visweshwar Sivasankaran, Olga Romanyuk, Alexander V. Mumyatov, Ivan Zhidkov, Sergey Tsarev, Ernst Z. Kurmaev, Alexander F. Shestakov, Olga V. Yarmolenko, Keith J. Stevenson, Pavel A. Troshin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report a facile synthesis of octahydroxytetraazapentacene (OHTAP) and the application of this redox-active material as a cathode for lithium- and potassium-ion batteries. While testing in lithium half-cells, OHTAP was used in the form of lithium salt and delivered the specific discharge capacity of 〉400 mAh g〈sup〉−1〈/sup〉 and the energy density of ~700 Wh kg〈sup〉−1〈/sup〉, which are impressive values achieved for organic electrode materials and can also be favorably compared with the characteristics of the current commercial benchmark cathodes based on LiFePO〈sub〉4〈/sub〉 (~155 mAh g〈sup〉−1〈/sup〉 and 543 Wh kg〈sup〉−1〈/sup〉). The potassium half-cells fabricated using pristine OHTAP depending on the electrode deposition technique showed specific capacities of 120–220 mAh g〈sup〉−1〈/sup〉, which are among the record values reported so far for this type of batteries. Quantum chemical DFT modelling provided insights in the mechanistic aspects of metallation of OHTAP and revealed that lithium- and potassium-ion storage might involve both the hydroquinone-quione chemistry as well as the redox transformations of pyrazine rings.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775319306950-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Meetu Bharti, Ajay Singh, Gajender Saini, Sudeshna Saha, Anil Bohra, Yuki Kaneko, A.K. Debnath, K.P. Muthe, Kazuhiro Marumoto, D.K. Aswal, S.C. Gadkari〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We demonstrate that introduction of p-type Bi〈sub〉0.5〈/sub〉Sb〈sub〉1.5〈/sub〉Te〈sub〉3〈/sub〉 nanostructures into the polymer matrix not only causes highly adherent drop-casted films of PEDOT:PSS (on Kapton sheets) to attain a free-standing nature but also brings a significant improvement in their thermoelectric properties. Hall and ESR measurements of these hybrid films clearly show that both the carrier concentration and mobility can be varied with Bi〈sub〉0.5〈/sub〉Sb〈sub〉1.5〈/sub〉Te〈sub〉3〈/sub〉 content. Whereas, results of X-ray diffraction, Raman and X-ray photoelectron spectroscopy confirm the enhancement in chain alignment and better connectivity among PEDOT:PSS and Bi〈sub〉0.5〈/sub〉Sb〈sub〉1.5〈/sub〉Te〈sub〉3〈/sub〉 nanosheets; leading to remarkable enhancement of electrical conductivity. These hybrid films, due to energy filtering of charge carriers at the organic/inorganic interface, exhibit improvement in the Seebeck coefficient also. In fact, such a synergetic combination of improved electrical conductivity and Seebeck coefficient expertly tailors the power factor (from order of ~10〈sup〉−4〈/sup〉 to 8.3 μW/mK〈sup〉2〈/sup〉) over a vast range. The optimized films are tested for their power conversion ability and a single thermoelement based device exhibits an open circuit voltage ~536 μV and current ~134 μA for a temperature difference of 53 °C. Such an evolution of organic-inorganic hybrid films in a flexible, free-standing motif with enhanced thermoelectric properties exhibit good potential for recovering heat from the curved hot surfaces.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775319307293-fx1.jpg" width="252" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Mohammed Srout, Karima Lasri, Mouad Dahbi, Abdelkader Kara, Laurene Tetard, Ismael Saadoune〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Being considered as a high Li-ion mobility material, Nasicon structured Li〈sub〉1.5〈/sub〉Fe〈sub〉0.5〈/sub〉Ti〈sub〉1.5〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉3〈/sub〉 phosphate material was synthesized via sol-gel route and electrochemically tested as electrode material for lithium-ion batteries. The material was tested in half-lithium electrochemical cells, within two voltage windows, 1.5–3.0 V and 0.5–3.0 V, and delivered first discharge capacities of 129 mAh/g and 567 mAh/g, respectively. Raman spectroscopy was used to confirm the material's structure before and during cycling. In addition, a comparative study of the electrochemical performance by the use of two different binders (PVDF and CMC), was conducted and showed a significant change in the electrochemical performance due to the change of the binder. Electrochemical impedance spectroscopy was used to evidence the electrodes' interface changes during cycling.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Kingo Ariyoshi, Satoshi Mizutani, Yusuke Yamada〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electrochemical impedance analysis was performed for Li[Li〈sub〉0.1〈/sub〉Al〈sub〉0.1〈/sub〉Mn〈sub〉1.8〈/sub〉]O〈sub〉4〈/sub〉 (LAMO) used as a lithium-insertion electrode by the diluted electrode method to identify the origin of resistance. Utilization of diluted electrodes, in which some portion of active material, LAMO, was systematically replaced with the same amounts of spectator Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 material to maintain the original structure of the LAMO electrode, is a promising method to discriminate between the resistance attributed to the lithium-insertion reaction in LAMO (charge-transfer resistance) and that accompanied by conduction of electron and/or ion in the porous electrodes. Electrochemical impedance spectra of the diluted electrodes consisted of two semicircles. The radius of a semicircle in the lower frequency region depends on the LAMO content in a diluted electrode, indicating that the semicircle is associated with charge-transfer resistance. On the other hand, the radius of the other semicircle in the higher frequency region is independent of the LAMO contents, suggesting that the semicircle is mainly related to the resistance accompanied by the porous structure of electrodes. Thus, the structure of lithium-insertion electrode should be carefully considered in designing high-energy and high-power lithium-ion batteries that employ thick electrodes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Rajesh Thomas, Shashikant P. Patole, Pedro M.F.J. Costa〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The electrochemical storage of aluminum in graphitic electrodes is a topic of much interest in the search for alternative battery systems. Here, we show that an Al-based battery can be realized using a cathode assembled with graphene flakes obtained from processed expandable graphite. When compared to pristine graphite (in this work, with 45 mAh/g at a current density of 214 mA/g), the capacity and cycle life performance are notably increased by the use of the graphene flakes (172 mAh/g, at 214 mA/g, after 100 cycles). The location and persistence of the charged choloraluminate species in the carbon materials was experimentally analyzed and complemented with computational modelling. Accordingly, and besides intercalation, grafting of the Al-species onto the graphene layers was identified as a possible mechanism that enhanced the performance of the processed expandable graphite cathodes. Such a phenomena would make the electrode more conductive and introduce a path for charge storage on its surface (akin to faradaic supercapacitors).〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775319307517-fx1.jpg" width="443" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Elizabeth Whiddon, Haihui Zhu, Xiuping Zhu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Salinity gradient (SG) energy is a renewable and clean energy resource that exists worldwide from the change in Gibbs free energy when two solutions with different salinities are mixed. More recently, concentration flow cells (CFCs) have been introduced as a new technology for SG energy recovery with the highest reported power density output to date as a result of the utilization of both the electrode potential and Donnan potential. In this study, multiple CFCs are connected to form a consecutive number of stacks, and systematic analysis is conducted to investigate the influence of both parallel and series electrical wire connections on the overall performance. For both wire connections, an effective increase in the overall power output with an increase in stack size is observed. The power densities normalized to the membrane area are however lower (3.7 W m〈sup〉−2〈/sup〉 in series and 5.8 W m〈sup〉−2〈/sup〉 in parallel, for 5-stacks) than that of the individual cell unit (8.9 W m〈sup〉−2〈/sup〉) because the back of the stack experiences cumulative mixing. Additionally, as a result of an ionic cross-conduction causing a parasitic current in the series cell, the parallel wire configuration is demonstrated to be more successful in the CFC stack than the series.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Martin Miller, Norman T.M. Baltes, Peter M. Rabenecker, Markus W. Hagen, Jens Tübke〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Supercapacitors are usually used as energy storage devices that work at a high current rate. This operating mode is often accompanied by the production of large amounts of heat inside the cell. Therefore, health monitoring of supercapacitors is still needed to avoid overheating and subsequent destruction. This paper presents a new method to determine the heat generation and the resulting temperature development of an aqueous hybrid capacitor based on extensive measurement data. We concentrate not only on the Ohmic power loss but also on heat phenomenon originating from side and overcharge reactions as well as entropy effects. The bearing of the final state of charge and the charging current on the temperature development is demonstrated. Finally, the temperature parameters of air and water cooled capacitors are simulated. The temperature distribution within the cell as a function of time is presented and discussed. The great advantage of the developed evaluation method is that it is an inexpensive method which can be realised in most test laboratories and that the measurements and simulations consider all crucial origins of power loss. The results obtained can be used to evaluate appropriate cooling systems. The method can be applied to capacitors and batteries.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Dipali S. Patil, Sachin A. Pawar, Jae Cheol Shin, Hyo Jin Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein, we report a simple one pot all hydrothermal synthesis route to grow nano structure of zinc-cobalt (Zn-Co) @ nickel-cobalt (Ni-Co) layered double hydroxides through oriented attachment growth with ultrathin nanosheets on 3D graphene foam using no additives or oxidants. The pseudocapacitor electrode based on Zn-Co@Ni-Co layered double hydroxides display an enhanced areal capacitance (7485 mFcm〈sup〉−2〈/sup〉, at 5 mVs〈sup〉−1〈/sup〉) and energy density (1202 mWhcm〈sup〉−2〈/sup〉, at 15 mAcm〈sup〉−2〈/sup〉) compared to pristine Zn-Co layered double hydroxides, with a greater cycling stability of 108% after 5000 charging-discharging cycles. We fabricate an all solid state symmetrical supercapacitor device with G-Zn-Co@Ni-Co//G-Zn-Co@Ni-Co layered double hydroxides that exhibits an areal capacitance of 1278 mFcm〈sup〉−2〈/sup〉, at 10 mVs〈sup〉−1〈/sup〉 and energy density of 171 mWhcm〈sup〉−2〈/sup〉, at 2.5 mAcm〈sup〉−2〈/sup〉. The credit of superior performance of these pseudocapacitor electrodes is to the easy access of electrolyte to the nanosheets, the conductivity enhancement by 3D graphene foam scaffold and the synergistic effect due to the composite structure of the Zn-Co@Ni-Co layered double hydroxides.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉A facile and low cost, hydrothermal technique was used to form a ZnCo@NiCo layered double hydroxide nanostructure composite electrode on graphene coated nickel foam for electrochemical supercapacitor.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775319307979-fx1.jpg" width="424" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Yachao Jin, Fuyi Chen, Jiali Wang, Longfei Guo, Tao Jin, Huazhen Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hydrogen oxidation and evolution reactions (HOR and HER) in alkaline media are very kinetically sluggish, which becomes one of major barriers for the breakthrough of anion exchange membrane fuel cells. Thus, developing highly active and economically competitive HOR/HER electrocatalysts for alkaline electrolytes is of critical importance to realize future hydrogen economy. Herein, we for the first time report a new class of platinum-rhodium nanoalloy aerogel (PtRh NAA) via a facile and controllable strategy as exceptional HOR/HER electrocatalysts in alkaline environment. The as-synthesized PtRh NAA features unique lamellar architecture, hierarchical pores system and abundant low-coordinated sites. Benefiting from the combined structural and electronic effects as well as bifunctional synergetic effects, the lamellar PtRh NAA delivers an excellent HOR specific activity of 1.25 mA cm〈sup〉−2〈/sup〉〈sub〉Pt+Rh〈/sub〉, which is 5.5 times higher than that of the commercial Pt/C (0.225 mA cm〈sup〉−2〈/sup〉〈sub〉Pt〈/sub〉). Meanwhile, its HER overpotential at −10 mA cm〈sup〉−2〈/sup〉 can be lowered to −55 mV, representing one of the highest HER activity so far. Moreover, no obvious deactivations are observed even after 5000 potential cycles for both HOR and HER, exhibiting excellent operation stability. These findings open a new field to design more advanced aerogels with high electrocatalytic performance.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775319307839-fx1.jpg" width="449" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 435〈/p〉 〈p〉Author(s): Akos Kriston, Ibtissam Adanouj, Vanesa Ruiz, Andreas Pfrang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Differential Scanning Calorimetry (DSC) and Thermal Gravimetry (TGA) combined with gas analysis are used to identify the main decomposition processes and to develop reaction kinetic models for thermal runaway modelling of Graphite – Lithium Nickel–Manganese–Cobalt-Oxide (NMC 111) cells. Heating rates of 5, 10 and 15 °C min〈sup〉−1〈/sup〉 with multiple replications are performed to determine the frequency factor, activation energy and the heat of reaction of the different sub-processes. It is found that both the anode and cathode decompose in multiple parallel and consecutive reactions between 5 °C and 600 °C. A double breakdown mechanism of the protecting Solid Electrolyte Interface (SEI) is suggested to describe the anode decomposition reactions. For the cathode, decomposition and evaporation of ethylene carbonate (EC), decomposition of NMC with the liberation of oxygen, combustion of EC with the liberated oxygen, decomposition of binder, decomposition of EC and combustion of carbon additive reactions are identified and modelled. The proposed model can be used to simulate thermal runaway initiation methods in a realistic way.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775319307451-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: July–December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 SoftwareX, Volume 10〈/p〉 〈p〉Author(s): Cornelis Marcel Pieter ’t Hart, Georgios Leontaris, Oswaldo Morales-Nápoles〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉This is an update to PII: 〈a href="https://www.sciencedirect.com/science/article/pii/S2352711018300608" target="_blank"〉S2352711018300608〈/a〉〈/p〉 〈p〉In this paper, we discuss ANDURYL, which is a Python-based open source successor of the MATLAB toolbox ANDURIL. The output of ANDURYL is in good agreement with the results obtained from ANDURIL and EXCALIBUR. Additional features available in ANDURYL, and not available in its predecessors, are discussed.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Xiangmei Li, Xinze Wu, Jin Wang, Qicheng Hua, Jinxiao Wu, Xing Shen, Yuanming Sun, Hongtao Lei〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, colloidal gold (CG), latex microspheres (LM), and time-resolved fluorescent microsphere (TrFM), were utilized as the antibody labeled tracers in three kinds of lateral flow immunochromatographic assays (LFIAs), which were established to detect tylosin (TYL) and tilmicosin (TIM) residues in milk and pork. The cut-off values of the CG-LFIA, LM-LFIA, and TrFM-LFIA for TYL in milk were 8, 4, and 2 ng/mL, respectively, and that for pork were 15, 8, and 4 μg/kg, respectively. The sample preparation of the three LFIAs is simple and fast, and the results can be acquired within 5-8 min. The three LFIAs have a strong cross-reaction to TIM and can be applied to simultaneously detect TIM. Forty milk samples were analyzed by both the three LFIAs and LC-MS/MS, the results showed a good correlation between the four methods, and no false positive or false negative results were found, indicating that the developed three assays could provide rapid, reliable, and multi-selective technical support for the on-site determination of macrolide antibiotics or other pollutants residues in a considerable amount of samples.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519312584-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Mohammad Khavani, Mohammad Izadyar, Mohammad Reza Housaindokht〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Different sensors composed of aptasensor have been largely designed for detection of many analytes recently due to the ease of detection, high sensitivity, and potential for high-throughput analysis. In this article, a joint theoretical and experimental study was performed to design new gold nanoparticle based colorimetric aptasensor. At the first step, by employing molecular dynamic (MD) simulations, twenty new RNA aptamers for detection of neomycin B (NB) were theoretically designed. The sensing ability and their binding affinity of these aptamers toward NB were investigated from the theoretical viewpoint and the predicted behaviors were compared with that of the wild type aptamer (AP-W). Theoretical results indicated that two aptamers of AP-M18 and AP-M20 have a greater affinity toward NB in comparison with AP-W. At the next step, AP-M18, AP-M20 and AP-W were synthesized and their affinity and selectivity toward NB were investigated by gold nanoparticles (AuNPs) based colorimetric method. On the basis of experimental results, the calculated limit of detection (LOD) values of AP-M18 and AP-M20 are 27 and 360 nM, respectively, which are lower than that of AP-W (470 nM). Moreover, quantum chemistry calculations indicated that van der Waals and electrostatic interactions may be the driving force of the NB complexation. A greater affinity of AP-M18 against NB can be explained by the possible stronger donor-acceptor interactions. A good agreement between different predicted properties with the experimental results suggests the ability of the theoretical methods to design new aptamers for detection of various targets.〈/p〉〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311463-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈p〉Experimental investigation indicates that the theoretical methods have an interesting ability for designing new aptasensors for detection of different targets.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Xiaohui Lu, Jin Wang, Guodong Lu, Bo Lin, Meizhuo Chang, Wei He〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉China grows and consumes numerous types of tea, which have diverse processing techniques. West Lake Longjing Tea is one of the most famous and popular varieties of tea in China. It is difficult for consumers to assess the quality of Longjing green tea, as it usually requires well-trained experts to make the judgement based on colour, aroma, and taste. To this end, we propose a quality identification system consisting of a self-developed electronic nose and a data analysis algorithm to assess the quality of West Lake Longjing Tea based on its aroma. The equipment was tested extensively in experiments conducted on real-world data. The results show that the proposed system is capable of distinguishing the tea grades accurately. Furthermore, we studied the quality specifications of Longjing tea sold by different brands and found that standard certified brands have more accurate quality identification criteria than non-standard certified brands. Our findings will assist customers and tea factories in evaluating the quality of Longjing Tea and guide the optimisation of quality standards.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 300〈/p〉 〈p〉Author(s): Hao Guo, Kun Qian, Anjiang Cai, Jun Tang, Jun Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We demonstrate a method for fabricating nanoparticles in a line at the top of silver wrinkled structures by tilting the substrate. The center of gravity of the colloidal droplets was moved backward, resulting in a small volume of droplets at the front of the colloidal droplet. The droplet rapidly evaporated, and the nanoparticles that remained formed lines of highly ordered nanoparticles. The distance between the nanoparticles changed after stretching the PDMS substrate due to the Poisson effect. An optimal plasma effect was achieved by controlling the distance between the nanoparticles. Finally, the Surface-Enhanced Raman Scattering (SERS) effects of CV and R6G molecules in water were determined, and the detection limit was 10〈sup〉−20〈/sup〉 M. This method provides an extremely high sensitivity SERS substrate for the detection of biomolecules.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Jin Her, Hunho Jo, Changill Ban〈/p〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Yongqiang Li, Jianfang Sun, Hehua Wei, Suihong Song〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Based on the analysis of the characteristics of modern karst and paleokarst outcrops, this study summarizes the features of subsurface reservoirs by using core, logging, seismic and production data, establishes the structural model of fault-controlled karst reservoirs, and points out the guiding significance of this structural model for development and production in the Tahe oilfield. Modern karst in southern China shows the three-component structural characteristics of fault-controlled karst which are fault core, damage zone, and host rock. The cavern is developed in the fault core and the fracture-vugs are fully developed. Paleokarst outcrops reveal the evolutionary process of fault-controlled karst reservoirs, the characteristics of caverns along the fault and the surrounding fracture-vuggy features. Seismic structure tensor attributes, ant-track attributes and amplitude spectrum gradient attributes are used to describe the external geometry, caverns, and large-scale fractures of fault-controlled karst reservoirs, and the small fractures and vugs can be described by using cores. According to the characteristics of modern karst, paleokarst and subsurface reservoirs, three architectural patterns of fault-controlled cavern complexes, fault-controlled caverns and fault-controlled vugs are summarized. Different architectural patterns of karst reservoirs lead to different production capacities. The architectural patterns have important guiding significance for new drilling and water or gas injection to improve oil recovery.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): M.E. Emetere〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recently, significant reserves of oil were discovered off the coast of Lagos State, southwest Nigeria. The lateral situation or compositions of the oil-bearing deposits is not clear because these findings are based on a particular position of a single well. The conventional methods of oil exploration have shown a fundamental theoretical shortcoming that may not be resolved, hence scientists or professionals may have to keep modifying the theories to explore different geological terrain. In this study, the remote sensing technique was adopted. The dataset were adopted from MERRA, Landsat 8 OLI and ETM imagery. The temperature distributions (soil and geothermal temperature) over the research area were calculated using existing algorithms to compliment the satellite remote sensing results. A prospective hydrocarbon deposits was suggested for further research work.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): T.N. Phan, Y.M. Zapata, C.S. Kabir, J.D. Pigott, M.J. Pranter, Z.A. Reza〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Despite the recent growth in oil production from unconventional reservoirs, existing hydraulically-fractured horizontal wells face challenges of poor recovery with the rapid production decline over a short life span. Enhanced recovery techniques, such as cyclic CO〈sub〉2〈/sub〉 injection can be a solution to this impending problem and lead to energy independence for the foreseeable future. However, mechanisms occurring around the hydraulically fractured wells are far from fully understood. The primary motivation of this study revolves around addressing this limitation. Specifically, we explored the evolution of various thermophysical properties occurring around hydraulically-fractured wells in liquid-rich unconventional reservoirs using a holistic, integrated modeling framework.〈/p〉 〈p〉Available well-logs and other data from Howard County in the Midland Basin formed the basis for constructing representative 3D structural models that capture the Midland Basin stratigraphy. We used a simulator to create multistage hydraulic fractures that allowed integration into numerical reservoir-flow simulation models. Then, both convective and diffusive flow within a multicomponent compositional simulation modeling paradigm is used to examine the role of molecular diffusion in performance under cyclic CO〈sub〉2〈/sub〉 injections in hydraulically-fractured well.〈/p〉 〈p〉The simulation results indicate that molecular diffusion yields an incremental oil recovery of 6% compared to models that do not. Our analysis reveals different thermophysical properties transition from near wellbore regions to outer regions into the rock matrix. Changes in total mole fractions of CO〈sub〉2〈/sub〉, methane, and hydrocarbons with C7+ fraction, pressure and saturation variation, viscosity reduction and the surface tension over 14 injection-soaking-production cycles are tracked. The analyses of the evolution of these thermophysical properties provide us with means to evaluate the efficiency of the solvent injection process. The simulation results explain how, when, and where CO〈sub〉2〈/sub〉 disperses into the reservoir.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 180〈/p〉 〈p〉Author(s): Wanderson Lambert〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, we propose a technique to solve the system of equations of mass balance for the salt solution and mass balance for salt in the solid phase introduced in the paper “Mathematical model of dissolution of particles of NaCl in well drilling: Determination of mass transfer convective coefficient”. In that paper, authors claimed that there is no technique to solve analytically the provided system of equations (actually, authors claimed that is possible an analytical solution for the “steady state” solution), however, from the mathematical viewpoint, the system of equations modelling this transport is a linear hyperbolic system of equations and it is possible to obtain the solution of this system by using the technique of characteristic waves. Since the model proposed in the paper cited can be used for several different transport equation models, it worth to present the general technique and solution that can be applied in other models in the context of transport phenomena.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 436〈/p〉 〈p〉Author(s): Wentao Fu, Ruijie Xu, Xiaoqing Zhang, Ziqin Tian, Henghui Huang, Jiayi Xie, Caihong Lei〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The hydroxyl groups in inorganic-organic hybrid poly (cyclotriphosphazene-co-4,4-sulfonyldiphenol) (PZS) exhibits some reactivity toward lithium ions. In this work, the core-shell structured silica-poly (cyclotriphosphazene-co-4,4′-sulfonyldiphenol) nanoparticles (SiO〈sub〉2〈/sub〉-PZS) are synthesized and the composite separator is prepared by coating on both sides of polyethylene (PE) microporous membrane. Compared to pure SiO〈sub〉2〈/sub〉 coated separator and PE membrane, the PE-SiO〈sub〉2〈/sub〉@PZS separator shows higher ionic conductivity. The corresponding discharge capacity at 8C rate reaches a value of 115 mA h g〈sup〉−1〈/sup〉, compared to 105 mA h g〈sup〉−1〈/sup〉 for PE membrane and 106 mA h g〈sup〉−1〈/sup〉 for PE-SiO〈sub〉2〈/sub〉 separator. The hydroxyl group and N、O atoms on the surface of PZS can coordinate with lithium ions to enhance the dissociation of lithium salt (LiPF〈sub〉6〈/sub〉), thus improving the ionic conductivity and discharge capacity. Meanwhile the lower interfacial impedance resistance for PE-SiO〈sub〉2〈/sub〉@PZS separator indicates intimate adhesion between electrode and separator. In a word, the SiO〈sub〉2〈/sub〉-PZS nanoparticles are a promising filler for enhancing the wettability and electrochemical performance of Lithium-ion battery separator.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 436〈/p〉 〈p〉Author(s): Fangfang Zheng, Huilong Dong, Yujin Ji, Youyong Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The development of high-performance cathode electrocatalysts in nonaqueous lithium-oxygen (Li–O〈sub〉2〈/sub〉) battery is mainly restricted by high charge/discharge overpotentials. Based on first-principles calculations, we theoretically explore the application potential of BC〈sub〉3〈/sub〉 and NC〈sub〉3〈/sub〉 nanosheets as the suitable cathode electrocatalysts. By analyzing the stable adsorption configurations of Li〈sub〉x〈/sub〉O〈sub〉2y〈/sub〉 (x = 0–4, y = 0–2) intermediates on BC〈sub〉3〈/sub〉/NC〈sub〉3〈/sub〉, it is confirmed that oxygen reduction reaction (ORR) on BC〈sub〉3〈/sub〉 follows four-electron pathway with (Li〈sub〉2〈/sub〉O)〈sub〉2〈/sub〉 as the discharge product, while for ORR on NC〈sub〉3〈/sub〉, (Li〈sub〉2〈/sub〉O〈sub〉2〈/sub〉)〈sub〉2〈/sub〉 is the discharge product following two-electron pathway. We then plot the corresponding free energy diagrams of charge/discharge processes and calculate the theoretical discharge and charge overpotentials (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉η〈/mi〉〈/mrow〉〈mrow〉〈mi〉O〈/mi〉〈mi〉R〈/mi〉〈mi〉R〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉η〈/mi〉〈/mrow〉〈mrow〉〈mi〉O〈/mi〉〈mi〉E〈/mi〉〈mi〉R〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉) along the optimal reaction pathways. Our results show that both the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉η〈/mi〉〈/mrow〉〈mrow〉〈mi〉O〈/mi〉〈mi〉R〈/mi〉〈mi〉R〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉η〈/mi〉〈/mrow〉〈mrow〉〈mi〉O〈/mi〉〈mi〉E〈/mi〉〈mi〉R〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 on BC〈sub〉3〈/sub〉 are considerably low (0.21 V and 0.36 V), indicating that BC〈sub〉3〈/sub〉 can serve as a high-performance cathode electrocatalyst. Meanwhile, the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉η〈/mi〉〈/mrow〉〈mrow〉〈mi〉O〈/mi〉〈mi〉R〈/mi〉〈mi〉R〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉η〈/mi〉〈/mrow〉〈mrow〉〈mi〉O〈/mi〉〈mi〉E〈/mi〉〈mi〉R〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 on NC〈sub〉3〈/sub〉 (0.37 V and 0.95 V) are comparable to previously reported materials following two-electron pathway (such as N-doped graphene), exhibiting practical values. Both the BC〈sub〉3〈/sub〉 and NC〈sub〉3〈/sub〉 nanosheets are stable enough for application in Li–O〈sub〉2〈/sub〉 battery, and dimethyl sulfoxide (DMSO) isn't recommended as an organic electrolyte when BC〈sub〉3〈/sub〉 works as the cathode catalyst.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775319308389-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 436〈/p〉 〈p〉Author(s): Yoon-Sok Kang, Dong Young Kim, Jaegu Yoon, JoungWon Park, Gyusung Kim, Yongnam Ham, Insun Park, Meiten Koh, Kwangjin Park〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A new synthetic method using biotemplating for fabrication of LiCoO〈sub〉2〈/sub〉 (LCO) for batteries of mobile products is developed. The LCO can be manufactured in various forms, and rapidly charged and discharged, even when using a thick electrode. Among three types of candidate biotemplates wood, cotton, and grass pollen, cotton was selected as the biotemplate considering its performance and potential for commercialization. Both the size of the primary particle and the shape of the secondary particle are controllable by using cotton. When using a thin electrode, the difference in capacitance between the LCO fabricated by the general method (solid-LCO) and the LCO made by using cotton (cotton-LCO) is within 3%, regardless of current density. On the other hand, the capacity difference in the case of a thick electrode between two samples is approximately 1.5 times higher than that observed for solid-LCO at very high current density (6C). The capacity retention values are 1.4% and 75.1% at 6C after the 100th cycle for solid-LCO and cotton-LCO, respectively. The superior performance at high current density for the cotton-LCO likely arises from decreasing the distance that the Li〈sup〉+〈/sup〉 ion must diffuse in the solid-state by connected nanoparticles.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 31 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 438〈/p〉 〈p〉Author(s): Yunhe Zhao, Hongxing Dong, Xinyi He, Jing Yu, Rongrong Chen, Qi Liu, Jingyuan Liu, Hongsen Zhang, Rumin Li, Jun Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electrode materials with a large internal surface area, tunable pore size, efficient transport of electrons and high ion-accessibility are highly desired in the development of advanced flexible supercapacitors. Recently, transition metal sulfides with rationally designed nanostructures have attracted considerable attention as electrode materials for supercapacitors. In this study, we report the synthesis of Zn〈sub〉0.76〈/sub〉Co〈sub〉0.24〈/sub〉S/NiCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 nanosheets grown on carbon cloth using a two-dimensional bimetallic Zn/Co zeolitic imidazolate framework (named as Zn/Co-ZIF-L) as a precursor through a simple and cost-effective chemical solution process. The ZIF-derived Zn〈sub〉0.76〈/sub〉Co〈sub〉0.24〈/sub〉S/NiCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 electrode nanosheets deliver an ultrahigh specific capacitance of 2674 F g〈sup〉−1〈/sup〉 at 1 A g〈sup〉−1〈/sup〉, a superior ratio performance and cycle stability. Furthermore, the as-fabricated Zn〈sub〉0.76〈/sub〉Co〈sub〉0.24〈/sub〉S/NiCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉//AC all-solid-state asymmetric supercapacitor (ASC) achieves a maximum energy density of 48.1 Wh kg〈sup〉−1〈/sup〉 as well as a power density of 837 W kg〈sup〉−1〈/sup〉, and a superior cycling performance of 91% retention after 5000 cycles. The detailed electrochemical kinetic analysis demonstrates that the total capacitance of Zn〈sub〉0.76〈/sub〉Co〈sub〉0.24〈/sub〉S/NiCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 is derived from its capacitive-effective charge storage mechanism. This ZIF-derived strategy provides a reasonable and simple way to synthesize transition metal sulfides as potential active materials for next-generation flexible supercapacitors.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S037877531931050X-fx1.jpg" width="252" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 31 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Power Sources, Volume 438〈/p〉 〈p〉Author(s): Hao-Jen You, Hsu-Shen Chu, Wen-Jin Li, Wen-Li Lee〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The thermoelectric effect is a promising source of renewable energy that can be used to interconvert thermal and electrical energy based on the Seebeck effect and Peltier effect. Conventional thermoelectric modules (CTEMs) cannot be bent to cover irregular surfaces such as the human body. Further, they are fragile and have expensive ceramic substrates. Hence, it is difficult to apply them, particularly in wearable devices. We demonstrate low-cost flexible thermoelectric modules (FTEMs) using flexible copper clad lamination as a substrate. The weight of an FTEM is only 0.43 g/cm〈sup〉2〈/sup〉, which is approximately 2.5 times lower than that of a CTEM (1.06 g/cm〈sup〉2〈/sup〉), even though the two devices use the same thermoelectric materials (n-type Bi〈sub〉2〈/sub〉Se〈sub〉0.3〈/sub〉Te〈sub〉2.7〈/sub〉 and p-type Bi〈sub〉0.5〈/sub〉Sb〈sub〉1.5〈/sub〉Te〈sub〉3〈/sub〉) fabricated using the same process. In addition, the output density of the FTEM is several tens of times higher than that of the CTEM with a temperature difference of 15 K. The FTEM also exhibits a cooler performance of 13.76%. This is particularly important for cases where the power density per unit area and weight are important, such as the applications of a thermoelectric module on human skin, automobiles, and spaceships. These results can be applied to improve the applications of thermoelectric modules.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0378775319310481-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Gao-Chao Fan, Zimeng Li, Yanwei Lu, Linzheng Ma, Huan Zhao, Xiliang Luo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Resulting from nonspecific adsorption or obvious biofouling, target detection in real biological media is a potential challenge for most of the biosensors. Herein, we first report an antifouling photoelectrochemical (PEC) cytosensor by using zwitterionic peptide. The typical cervical carcinoma Henrietta Lacks (HeLa) cell was chosen as a target model and the aptamer AS1411 was used as its recognition element. TiO〈sub〉2〈/sub〉 nanoparticles (NPs) and ZnIn〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 nanocrystals (NCs) were modified in order on a bare indium–tin oxide (ITO), forming ITO/TiO〈sub〉2〈/sub〉/ZnIn〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 electrode as the PEC matrix to immobilize aptamer AS1411 and zwitterionic peptide. The fabricated PEC cytosensor exhibited a high sensitivity toward HeLa cell detection, with the detection limit of 34 cells/mL. Besides, owning to excellent antifouling property of the zwitterionic peptide, evidently reduced nonspecific adsorption of the cytosensor was realized in the biological media.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉An efficient but general strategy for antifouling photoelectrochemical cytosensor was proposed by introducing zwitterionic peptide. The cytosensor demonstrated the distinct merits of high sensitivity and low fouling in the biological media.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311955-ga1.jpg" width="283" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 182〈/p〉 〈p〉Author(s): Sheng Fu, Zhen Liu, Yi-ming Zhang, Xin Wang, Ning Tian, Ling Li, Hui-lai Wang, Tao Jiang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Wulan-Hua Sag in the south of Erlian Basin has large oil and gas resource, whereas the source rocks genetic potential and oil-rock correlation in its Aershan Formation (K1ba) and First member of Tengge'er Formation (K1bt1) are still unclear. We performed organic geochemistry analyses of oil and mudstone samples to divide crude oil types, evaluate source rock potential, and establish relatively accurate oil-source correlation. The results indicate that the source rocks in K1ba and the Lower interval in First member of Tengge'er Formation (LK1bt1) belong to good source rocks, characterized by high organic matter abundance, oil-prone kerogen type, and relatively high thermal maturity. K1ba and K1bt〈sub〉1〈/sub〉 crude oil samples were divided into two types sourced from different Wulan-Hua source rocks. Type A oil is distributed in the K1ba and LK1bt1 of Saiwusu uplift and Hongjing uplift, and featured by a low gammacerane amounts (the majority of gammacerane/C〈sub〉30〈/sub〉H 〈 0.30), and high Pr/Ph (ranging from 0.18 to 1.18, with mean value of 0.78). It has high mature organic matter mainly originated from terrestrial plant and dominant terrestrial plant. This type of oil was sourced from the K1ba source rocks in the Saiwusu uplift. Type B oil occurs in the LK1bt1 of the Tumuer Uplift and north sub-sag, and have high gammacerane abundance (the majority of gammacerane/(C〈sub〉30〈/sub〉 〉 0.3), and low Pr/Ph (ranging from 0.38 to 0.76, with mean value of 0.63). Its organic matter includes dominant terrestrial plant source, and this oil type should be sourced from the LK1bt1 source rocks in the Saiwusu uplift.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 182〈/p〉 〈p〉Author(s): Wei Liu, Wei David Liu, Jianwei Gu, Xinpu Shen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The sedimentary rhythm of Chinese oilfields is complicated and the heterogeneity is extremely strong. Allocating water absorption of each sublayer by dividing coefficient or numeric simulation cannot accurately reflect the actual water injection of the reservoir. Calculation based on water absorption profile monitored on site is the most commonly used method in oil field. However, access to these type of data is limited due to its cost and time related to acquisition. In this study, a machine learning approach was adopted to predict water absorption in sublayer based on geologic and production parameters of injectors and producers. On the one hand, it can save test costs. On the other hand, it can continuously predict water absorption of sublayers, and make up for water injection wells with insufficient injection profiles. A handful of training observations are obtained from on-site monitoring. Interwell connectivity is first conducted to identify connected producers for injectors. Introducing interwell connectivity helps to constitute predictor variables and yield significant improvements in feature selection. Connectivities in the well group are represented by similarity between injection sequence and production sequence, which is computed by Dynamic Time Warping. Average importance of predictors are then measured based on Mean Decrease Impurity, Mean Decrease Accuracy, and Ridge regression. Some relative important features are selected to consist the final predictors. The Extreme Gradient Boosting model is developed and then trained for making predictions given any set of observations. The proposed approach is validated by using actual field case from SL oilfield, China. Results show a significant correlation between predictions and actual value from on-site monitoring.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 183〈/p〉 〈p〉Author(s): Isty Adhitya Purwasena, Dea Indriani Astuti, Muhamad Syukron, Maghfirotul Amaniyah, Yuichi Sugai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Microbial enhanced oil recovery (MEOR) is a proven tertiary recovery technique. Biosurfactant is a microbial bioproduct that plays an important role in MEOR applications. This study aimed to test biosurfactant stability using a design experiment based on response surface methodology. First, isolation and screening for potential biosurfactant-producing bacteria from crude oil samples was performed, followed by their characterization. A biosurfactant core flooding experiment was also conducted to examine bacterial activity on MEOR. Thirty-one sequential isolates of bacteria were screened based on qualitative and semi-qualitative parameters. One selected biosurfactant-producing bacterium was identified as 〈em〉Bacillus licheniformis〈/em〉 DS1 based on phylogenetic analysis of the 16S rRNA gene. This bacterium had the highest emulsification activity (E〈sub〉i24〈/sub〉 = 65.19%) in light crude oil and could reduce the interfacial tension between oil and water with an effective critical-micelle concentration of 157.5 mg/L. The biosurfactant was observed as a growth-associated metabolite type and the Fourier transform infrared spectrum revealed that the biosurfactant produced belonged to a group of lipopeptides. The biosurfactant has good stability in maintaining emulsification activity at pH 4–10, high temperatures up to 120 °C, and with an NaCl concentration up to 10% (w/v). Based on response surface methodology using the Box–Behnken experimental design, the optimum condition for the most stable biosurfactant is pH 12, a 40 °C temperature and 10% salinity, with an E〈sub〉i24〈/sub〉 value of 94.28%. Core flooding experiments with biosurfactant resulted in 5.4% additional oil recovery. Therefore, this biosurfactant shows a high potential application for MEOR.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 183〈/p〉 〈p〉Author(s): Jiangfeng Cui〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The pre-Darcy flow phenomena in porous media is still not well understood, and the liquid slip mechanism in shales is controversial. Both issues need more exploration. In the field of microfluidic research, the concept of the slip length is widely employed to characterize the deviation from the no-slip flow, and it is recognized that the slip is rate-dependent. For the first time, the rate-dependent slip is proposed as an explanation for the pre-Darcy flow phenomena in porous media and the compromise between existing controversial views with regard to the liquid slip flow in shales based on careful analysis, and then such slip is incorporated in the one-dimension unsteady diffusion equation for liquids. The finite difference method is employed to numerically solve the equation, and detailed sensitivity analysis is conducted for the critical shear stress, the pore radius and the slip length. The results are summarized, and suggestions for future research are provided. This work can provide new insight into the pre-Darcy flow phenomena in the nanoporous media, and can compromise between existing controversial views regarding the liquid slip mechanism in shales. More importantly, this subject is also significant to research and develop EOR methods in shale reservoirs.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 183〈/p〉 〈p〉Author(s): Yongfei Yang, Yingwen Li, Jun Yao, Kai Zhang, Stefan Iglauer, Linda Luquot, Zengbao Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The incompatibility between workover fluid and reservoir rock is one of the causes of formation damage. Fines migration and clay swelling are considered as the major mechanisms responsible for formation damage, which results in declining productivity. However, there has been limited visualized evidence of pore structural changes during formation damage. This paper establishes a formation damage evaluation method for sandstone reservoirs based on X-ray micro-computed tomography (CT) analysis. We presented conclusive evidence for clay swelling and fines migration during workover fluid flooding and formation liquid flooding. Water sensitivity and flow rate sensitivity tests were performed on a Dongying sandstone (heterogeneous argillaceous sandstone) plug. In addition, the plug was micro-CT imaged before and after flooding with workover fluid and formation liquid at medium resolution (24 μm voxel size); the changes in core permeability and the associated changes in 2D and 3D pore space were analyzed. We found that the sandstone pore space was partially blocked by clay minerals and moving particles, leading to significantly decreased porosity (5.17%–4.19% for sample 1, 5.38%–2.76% for sample 2) and permeability (3.38 × 10〈sup〉−3〈/sup〉 μm〈sup〉2〈/sup〉 to 1.28 × 10〈sup〉−3〈/sup〉 μm〈sup〉2〈/sup〉 for sample 1, 13.30 × 10〈sup〉−3〈/sup〉 μm〈sup〉2〈/sup〉 to 3.15 × 10〈sup〉−3〈/sup〉 μm〈sup〉2〈/sup〉 for sample 2). This permeability decrease was caused by a decrease in the average pore radius and coordination number. Moreover, increased micro-CT intensity was measured by comparison of initial and final tomogram images, representing clay swelling & blockage of pores during the displacement and a generally lower porosity. This work visualized microscale formation damage, which reminds that incompatibility between workover fluid and reservoir rock damages formation seriously and the fluid injection rate should be lower than the critical flow rate when developing a reservoir with a strong water sensitivity and flow rate sensitivity.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0920410519307776-fx1.jpg" width="245" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 183〈/p〉 〈p〉Author(s): Xin Li, Deli Gao, Baoping Lu, Yijin Zeng, Jincheng Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Maximum extension length prediction model for horizontal wells can be used to evaluate the horizontal well's extension capability and predict its maximum measured depth, which is of great significance to the production and economic benefits of horizontal wells. However, the differential sticking is not considered in previous prediction model. To overcome this shortcoming, a modified model considering differential sticking is established based on constraints of wellbore stability, differential pressure, and filtration loss simultaneously during the drilling, tripping processes and static state. Then a horizontal well is analyzed and its maximum extension length is predicted. Results show that within the conventional mud weight window, three ranges of drilling fluid density can be determined, including the first range, the second range and the reasonable range of drilling fluid density. However, only the reasonable range of drilling fluid density can satisfy all constraints of the modified prediction model, including the wellbore stability, differential pressure, and filtration loss simultaneously. Compared with the original model, the predicted well's maximum extension length decreases when the differential sticking is considered. However, it is more accurate, avoiding drilling hazards in actual drilling operation due to the excessive designed measured depth and unreasonable drilling parameters. Moreover, the maximum speeds of casing running down/pulling out are also determined and added to the modified model. Therefore, the modified model with reasonable drilling fluid density and adjusted running down/pulling out speed is the optimal modified model to predict maximum extension length and avoid differential sticking, which can also ensure that the horizontal well's designed measured depth can be successfully achieved. This study is of great significance to improve the prediction accuracy of horizontal well's maximum extension length and avoid drilling hazards, especially the differential sticking. Moreover, it also plays a guiding role in the selection of reasonable drilling fluid density during horizontal drilling.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 183〈/p〉 〈p〉Author(s): Liang Mu, Hans Ramløv, T. Max M. Søgaard, Thomas Jørgensen, Willem A. de Jongh, Nicolas von Solms〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Antifreeze proteins (AFPs) are characterized by their ability to protect organisms from subfreezing temperatures. They constitute a class of promising candidates as environmentally kinetic hydrate inhibitors (KHIs). In this study, the effectiveness of an insect cell expressed novel monomeric streptavidin fusion protein version of 〈em〉Rhagium mordax〈/em〉 RmAFP1 antifreeze protein (mSA-RmAFP1), and four amino acids (histidine, lysine, tyrosine and proline), on CH〈sub〉4〈/sub〉 hydrate nucleation, growth and decomposition was investigated using a rocking cell apparatus, then compared with the commercial inhibitors Polyvinylpyrrolidone (PVP) and Luvicap Bio. It was found that CH〈sub〉4〈/sub〉 hydrate nucleation and growth exhibited good repeatable results under experimental conditions. The results showed that 2250 ppm mSA-RmAFP1 can inhibit CH〈sub〉4〈/sub〉 hydrate nucleation as effectively as PVP at the same concentration. The histidine, lysine, tyrosine and proline exhibited weak inhibition effect on CH〈sub〉4〈/sub〉 hydrate nucleation. The mSA-RmAFP1 decreased CH〈sub〉4〈/sub〉 hydrate growth rate and production in the fresh and memory solutions. The CH〈sub〉4〈/sub〉 hydrate formed in the solutions containing various tested KHIs present slightly lower onset decomposition temperatures than the non-inhibited system under experimental conditions. The promising performance of the insect cell expressed mSA-RmAFP1 could promote the further development of green hydrate inhibitors. The production of this protein through insect cell line fermentation provides a platform for the future production and optimization of AFPs for hydrate inhibition.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Desalination, Volume 470〈/p〉 〈p〉Author(s): Francisco J. Alcalá〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The chloride-to-bromide molar ratio (R ≡ Cl/Br) is widely used in tracing groundwater salinity. Less experience exists on how some industrial processes such as the reverse osmosis (RO) water treatment modify the R value of desalinated water (P) and reject brine (T), and even less on how distinctive for hydrogeological applications the R changes are. This paper assesses the Cl/Br ratio usefulness to identify the effect of P and T on groundwater systems. First, the experimental R changes produced in P and T during standard RO operations and treatments of raw (I) seawater, brackish groundwater, and tertiary-treated domestic wastewater in nine RO plants (three in Gran Canaria Island and six in south-eastern continental Spain) were determined by means of the X〈sub〉P〈/sub〉 = R〈sub〉P〈/sub〉/R〈sub〉I〈/sub〉 (R change in P) and X〈sub〉T〈/sub〉 = R〈sub〉T〈/sub〉/R〈sub〉I〈/sub〉 (R change in T) ratios. X〈sub〉P〈/sub〉 and X〈sub〉T〈/sub〉 were respectively 0.90 and 1.07 for treatment 1 (weak pre-acidification) in one RO plant, 0.82 ± 0.09 and 0.94 ± 0.05 for treatment 2 (weak pre-acidification and weak pre-chlorination) in five RO plants, 0.63 and 0.97 for treatment 3 (moderate pre-acidification and strong pre-chlorination) in one RO plant, and 3.21 ± 2.02 and 1.00 ± 0.00 for treatment 4 (post-chlorination) in two RO plants. P was for irrigation (treatments 1 to 3) and for domestic use (treatment 4). Latter, the experimental X〈sub〉P〈/sub〉 and X〈sub〉T〈/sub〉 ratios were input data for six theoretical mixing scenarios aimed at showing how groundwater R changes in response to progressive contributions of P and T produced from different I water. The Cl/Br ratio enables to identify the effect of P from treatments 3 and 4, is scarcely effective for treatments 1 and 2, and is especially useful when P produced from seawater is used in other aquifer having different R. The Cl/Br ratio did not clearly identify T from any treatment.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0011916419306988-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Enzyme and Microbial Technology, Volume 132〈/p〉 〈p〉Author(s): Gyumin Son, Thi Thanh Hanh Nguyen, Byeongsu Park, Sohyung Kwak, Juhui Jin, Young-Min Kim, Young-Hwan Moon, Sunghee Park, Seong-Bo Kim, Doman Kim〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Transglycosylation is one of enzymatic methods to improve the physical and biochemical properties of various functional compounds. In this study, stevioside glucosides were synthesized using sucrose as a substrate, stevioside (Ste) as an acceptor, and dextransucrase from 〈em〉Leuconostoc mesenteroides〈/em〉 B-512 F/KM. The highest Ste conversion yield of 98% was obtained with 50 mg/mL Ste, 800 mM sucrose, and dextransucrase 4 U/mL at 28 °C for 6 h. The concentration of Ste was unchanged while of Ste-G1 was increased from 7.7 mM to 9.1 mM as the Ste acceptor reaction digest was treated with dextranase from 〈em〉Lipomyces starkeyi〈/em〉. Ste-G1 (13-〈em〉O〈/em〉-β-sophorosyl-19-〈em〉O〈/em〉-β-isomaltosyl-steviol), Ste-G2 (13-〈em〉O〈/em〉-(β-(1→6) glucosyl)-β-glucosylsophorosyl-19-〈em〉O〈/em〉-β-isomaltosyl-steviol), and Ste-G2′ (13-〈em〉O〈/em〉-β-sophorosyl-19-〈em〉O〈/em〉-β-isomaltotriosyl-steviol) were determined by NMR. These glucosylated Ste showed increased stabilities at pH 2, 60 °C for 48 h as compared to Ste. Ste-G1, Ste-G2, and Ste-G2′ inhibited the insoluble glucan synthesis from sucrose by mutansucrase from 〈em〉Streptococcus muntans〈/em〉 by the transfer of the glucosyl group of sucrose to Ste-G1, Ste-G2, and Ste-G2′. The relative water solubility of curcumin, pterostilbene or idebenone was increased by Ste or Ste glucosides treatment. Ste and Ste-G1 restored cell viability in RAW264.7 cells at concentrations up to 8 mg/mL and inhibited nitric oxide production in LPS-induced RAW264.7 cells with IC〈sub〉50〈/sub〉 of 3.29 and 1.87 mg/mL.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0141022919301504-ga1.jpg" width="339" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Desalination, Volume 469〈/p〉 〈p〉Author(s): Jin Tang, Chuyi Wang, Wenjing Xie, Yahao Xia, Tao Yu, Zhili Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tubular still is one of the most promising desalination devices. This paper presents hydrophilic modification of the outer surface of the seawater trough in a tubular still, so that the hydrophilically modified outer surface can serve as an evaporation surface when it is wetted with the overflowing seawater from the trough. To experimentally verify and examine the effect of hydrophilic surface modification, a small tubular still was constructed with a seawater trough of 63 mm in diameter and 1.9 m in length. The experimental results show that at the operating temperature of 80 °C, the hydrophilically modified surface can increase the yield rate by 24.9%. Under the condition with a constant input power of 100 W, the hydrophilically modified surface can increase the gained output ratio (GOR) of the tubular still by 44.4%. In addition, a heat and mass transfer model of tubular still is also presented for a theoretical performance prediction of the effect of hydrophilic surface modification. A comparison exhibits the maximum deviation of 18.7% between the theoretical and experimental results.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Solid-State Electronics〈/p〉 〈p〉Author(s): Paul Clifton, Andreas Goebel, Robert Mulfinger, Amy Child, Sherry Straub, Ryan Sporer, Rick Carter, Jon Kluth, Jamie Schaeffer, Bich-Yen Nguyen, Guillaume Chabanne, Nicolas Daval, Walter Schwarzenbach, Manish Hemkar, Schubert Chu, Steve Moffatt〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report for the first time the implementation of SiGe buried stressors in the context of research and development of an advanced foundry FDSOI process and the observation of improved transconductance and current drive performance of n-channel FDSOI MOSFETs. Epitaxial SiGe stressors grown by CVD at Applied Materials were incorporated under the buried oxide of 300 mm FDSOI wafers by Soitec using lower temperature SOI bonding, splitting and thinning processes and the wafers were subsequently processed through an FDSOI development line at GLOBALFOUNDRIES. The use of FDSOI with buried stressor under the BOX eliminates the risk of extended defects in the epitaxial SiGe layer penetrating up into the SOI channel and also provides an opportunity to obtain a high level of strain in any semiconductor on insulator. A 70 nm thick SiGe buried stressor with 20% Ge is shown to provide a 10% improvement in I〈sub〉dsat〈/sub〉 at a fixed I〈sub〉off〈/sub〉 for n-FETs with 20 nm gate length and transconductance, gm is correspondingly improved by 15%.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biomass and Bioenergy, Volume 129〈/p〉 〈p〉Author(s): Sara Rajabi Hamedani, Andrea Colantoni, Francesco Gallucci, Mariangela Salerno, Cristian Silvestri, Mauro Villarini〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Woody biomass has a considerable potential for energy purposes specially after densification processes which convert these materials into solid biofuels with higher energy density. This study focuses on the energy and environmental assessment of pellet production system from vine and olive grove woody biomass. The life cycle assessment (LCA) from grape and olive cultivation up to packed pellet production, ready for delivery to final users was conducted to quantify the eco-profile of agro-pellet production. The results of comparative analysis revealed that pellet production from both biomasses is dominated by cultivation phase. Vine pellet production was more dependent on chemical fertilizers specially potassium sulfate, but olive pellet production was more dependent on copper oxide pesticide. Primary energy use per MJ energy of vine pellet was greater than that of olive pellet (0.6 vs. 0.19). On the other hand, energy return ratio of olive pellet was three times of that of vine pellet (5.22 vs. 1.7). Nevertheless, olive pellet had higher environmental impacts in the forms of human toxicity, freshwater ecotoxicity and marine ecotoxicity. Consequently, sensitivity analysis investigates the impact of variation in input parameters of fertilizers, pesticides, machinery, diesel fuel, transport and pelletizing process on LCA results.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Xiang Tao, Tan Dai Nguyen, Hao Jin, Ran Tao, Jingting Luo, Xin Yang, Hamdi Torun, Jian Zhou, Shuyi Huang, Lin Shi, Des Gibson, Michael Cooke, Hejun Du, Shurong Dong, Jikui Luo, YongQing Fu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Manipulating biological cells or microparticles in three dimensions (3D) is invaluable for many biomedical applications, and recently effective and rapid manipulations of microparticles in 2D and 3D within microchannels or chambers using surface acoustic waves (SAWs) with bulk piezoelectric materials have been reported. However, these are generally expensive, or brittle and cannot be easily integrated into a single lab-on-chip. In this paper, we realized microparticle/cell patterning and 3D manipulation of yeast cells inside a chamber with a height of 1 mm using thin film ZnO/Si SAW devices. Effects of SAW frequency, channel width and thickness on alignment of microparticles were firstly investigated, and positions of the microparticles in the direction of SAW propagation can be controlled precisely by changing the phase angle of the acoustic waves from the ZnO/Si SAW device. A numerical model has been developed to investigate the SAW acoustic field and the resulted 3D motions of microparticles under the acoustic radiation forces within the microchamber. Finally, we realized and observed the 3D patterning of yeast cells within the microchannel. Our work shows a great potential for acoustofluidic, neural network research and biomedical applications using the ZnO/Si SAW devices.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Radiation Measurements〈/p〉 〈p〉Author(s): I.S. Peracchi, J. Vohradsky, S. Guatelli, D. Bolst, L.T. Tran, D.A. Prokopovich, A.B. Rosenfeld〈/p〉 〈div xml:lang="en"〉 〈h5〉〈span〉Abstract〈/span〉〈/h5〉 〈div〉 〈p〉Astronauts are exposed to high-energy cosmic radiation which may have harmful health effects. At the altitude of the International Space Station (ISS), the main radiation sources are Galactic Cosmic Rays (GCRs), Solar Particle Events (SPEs) and trapped protons of the Van Allen Belts. The radiation field mainly consists of protons, helium nuclei and heavy ions with energies up to hundreds of GeV/n. A powerful approach to determine the effect of space radiation on astronauts is microdosimetry. The Centre for Medical Radiation Physics is active in the development of Silicon-On-Insulator (SOI) microdosimeters, as an alternative to Tissue Equivalent Proportional Counters (TEPCs) for radiation protection purposes. SOI microdosimeters are portable and do not require a high-voltage power supply. They consist of a matrix of silicon Sensitive Volumes (SV), which mimic the dimensions of biological cells.〈/p〉 〈p〉In this study, we investigated for the first time the response of the 3D “Mushroom” microdosimeter, a type of SOI microdosimeter in the Columbus module of the ISS. Tissue-equivalent microdosimetric spectra of GCRs, SPEs, and trapped protons were obtained to estimate the dose equivalent delivered to the astronauts. Results demonstrate a non-negligible production of secondary particles due to the propagation of space radiation through the wall of the Columbus and the microdosimeter. A number of heavy ions were detected with high lineal energies, these events pose a significant hazard in terms of radiation protection.〈/p〉 〈p〉Moreover, the dose evaluation shows a good agreement with experimental data found in the literature, confirming the suitability of our Geant4 model and the feasibility of using the SOI microdosimeter for ISS astronauts’ personal dosimetry.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Oleg Lupan, Vasile Postica, Thierry Pauporté, Bruno Viana, Maik-Ivo Terasa, Rainer Adelung〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, we investigated performances of individual and multiple networked Au nanoparticles (NPs)-functionalized ZnO nanowires (NWs) integrated into nanosensor devices using dual beam focused ion beam/scanning electron microscopy (FIB/SEM) and tested them as gas sensors at room temperature. Such important parameters as diameter and relative humidity (RH) on the gas sensing properties were investigated in detail. The presented results demonstrate that thin Au/ZnO NWs (radius of 60 nm) have a gas response of 〈em〉I〈sub〉gas〈/sub〉/I〈sub〉air〈/sub〉〈/em〉 of about 7.5–100 ppm of H〈sub〉2〈/sub〉 gas which is higher compared to 〈em〉I〈sub〉gas〈/sub〉/I〈sub〉air〈/sub〉〈/em〉 of about 1.2 for NWs with a radius of 140 nm. They have a low dependence of electrical parameters on water vapors presence in environment, which is very important for practical and real time applications in ambient atmosphere. Also, the devices based on multiple networked Au/ZnO NWs demonstrated a higher gas response of 〈em〉I〈sub〉gas〈/sub〉/I〈sub〉air〈/sub〉〈/em〉 about 40 and a lower theoretical detection limit below 1 ppm compared to devices based on an individual NW due to the presence of multiple potential barriers between the NWs. The corresponding gas sensing mechanisms are tentatively proposed. The proposed concept and models of nanosensors are essential for further understanding the role of noble metal nanoclusters on semiconducting oxide nanowires and contribute for a design of new room-temperature gas sensors.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311761-ga1.jpg" width="265" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Chao Gan, Wei-Hua Cao, Min Wu, Xin Chen, Yu-Le Hu, Kang-Zhi Liu, Fa-Wen Wang, Suo-Bang Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rate of penetration (ROP) prediction is crucial for the optimization and control in drilling process due to its vital role in maximizing the drilling efficiency. This paper proposes a novel intelligent model to predict the drilling ROP considering the process characteristics. First, the geological background and the drilling process of the case study are described. Based on the mechanism and frequency spectrum analysis, the strong nonlinearity and different low-frequency and high-frequency data noises between the data variables are detected. After that, the intelligent model is established via three stages. In the first stage, a wavelet filtering method is introduced to reduce these noises in the drilling data. In the next stage, the model inputs are determined by the mutual information method, which significantly decreased the model redundancy. In the last stage, a hybrid bat algorithm is proposed to optimize the hyper-parameters of the support vector regression model. Finally, the proposed model is validated by using the data from a drilling site in the Shennongjia area, Central China. The results demonstrate that the proposed method outperforms eight well-known methods and another three methods without different data preprocessing procedures in prediction accuracy.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Zheng Sun, Keliu Wu, Juntai Shi, Yuanhong Li, Tianying Jin, Qingyang Li, Xiangfang Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A detailed study for production prediction methods under various drainage schedules for under-saturated coalbed methane wells is performed. In terms of the relationship between the value of average reservoir pressure and the critical desorption pressure, whole production life of under-saturated coalbed methane wells is divided into two periods, and the material balance equation in each period is derived respectively. Combining the two-period material balance equation and productivity equation under pseudo-steady state, a novel production prediction method is developed. Excellent agreements between predicted water/gas production rates from the proposed method and those from numerical simulator clarify the reliability successfully. Results demonstrate that (a) matrix shrinkage effect and effective permeable capability can significantly contribute to the production rise; (b) For the drainage schedule (FWFB), with the increase of the fixed water production rate, the drainage period will shorten; (c) For the drainage schedule (RDFB), sharp decrease of formation pressure will take place.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Matthew Morte, Berna Hascakir〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Candidacy of any reservoir as a microwave absorber is predicated on the complex permittivity of the sample. Modeling both the penetration and absorption dynamics of the electromagnetic wave in the reservoir is dependent on realistic estimation of this parameter. Therefore, it becomes necessary to understand the inherent intricacies of complex permittivity in the reservoir. Reservoirs are comprised of both a void space represented by the porosity parameter as well as the rock matrix and can be treated as a binary mixture of the two. Mixing rules can then be introduced and have been shown to be a viable means of estimating the dielectric response. The behavior of the bulk material is considered to be an extension of the isolated contribution of the separate parts. Therefore, by characterizing the response of the individual components of the mixture, the overall response can be estimated. Utilization of mixing rules enables efficient estimation of the dielectric properties anywhere in the reservoir as a function of the rock matrix, fluid saturation, and porosity. The absorptive capacity of the reservoir can then be described which is used to screen the efficacy of the material for microwave introduction. Both the real and imaginary components of complex permittivity are measured on nine consolidated core samples of varying lithology and fluid saturation over the frequency range of 400 MHz to 6 GHz. Experimental data is compared to various mixing rules commonly implemented to determine validity and viability of the estimation of complex permittivity for consolidated samples.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Qingsong Cheng, Min Zhang, Hongbo Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Test analyses such as pyrolysis, soluble organic matter extraction, group component separation and GC-MS were conducted to 22 source rock samples and 28 crude oil samples from deep lacustrine facies of Funing Formation in Subei Basin. Source rocks stayed at the low maturity-mature stage (Ro:0.58%–0.71%), while crude oil stayed at the mature stage (Rc:0.71%–0.88%). The Pr/Ph values of samples in the research area ranged between 0.16 and 0.62. These samples could be classified as Sterane/Hopane〉1 and Sterane/Hopane〈1. For all the samples, the C〈sub〉29〈/sub〉 Steranes content was high; had inverse “L” distribution in ααα20RC〈sub〉27〈/sub〉-ααα20RC〈sub〉28〈/sub〉-ααα20RC〈sub〉29〈/sub〉 regular sterane; αα20R-Sterane played a dominant role; abundances of ββ- and 20S-Sterane were low. As for samples of Sterane/Hopane〉1, G/C〈sub〉30〈/sub〉H ranged between 0.63 and 2.56, and the Sterane isomerization was very low. As for samples with Sterane/Hopane〈1, G/C〈sub〉30〈/sub〉H ranged between 0.04 and 0.46 and the Sterane isomerization was higher than the former. Abnormal distribution of Sterane isomerization was rarely influenced by thermal dynamic effects and sources, but was mainly influenced by the sedimentary environment. A lot of references reported Sterane isomerization with abnormally high abundance under the high-salinity environment. However, the finding obtained by the research that the higher water salinity corresponded to the lower degree of Sterane isomerization was discovered for the first time. The C〈sub〉29〈/sub〉 Sterane abundance was high and the C〈sub〉29〈/sub〉/C〈sub〉27〈/sub〉 regular sterane ratio was constant and would not vary with changes of environmental parameters and biological source parameters. Sterane content was not correlated with tricyclic terpene of algae sources, but was positively correlated with ETR of the aquatic organism source, while it had very good positive correlation with Gammacerane. In addition, samples with the high Sterane content had high abundance in Carotene, C〈sub〉24〈/sub〉+alkyl-cyclohexane and C〈sub〉21〈/sub〉+isoprenoid alkanes. Through profound analysis and reference survey, it is found that the abnormally high abundance of C〈sub〉29〈/sub〉 Sterane of samples in the research area may be correlated with halophilic protozoon in salinized deepwater lakes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Ahmed Farid Ibrahim, Hisham A. Nasr-El-Din〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉After hydraulically fracturing of shale gas wells, theoretical and experimental studies showed that over 75% of the injected water-based fracture fluids left unrecovered. The trapped water causes permeability damage and productivity impairment. The flowback water also tends to be highly saline, often with TDS contents of as much as 200,000 ppm. This study aims to investigate the effect of well shut-in before flowback stage (the soaking process) on the production of shale and tight sandstone formations.〈/p〉 〈p〉Shale and sandstone samples were analyzed by X-ray diffraction (XRD). Marcellus shale and Kentucky sandstone cores were used. A modified core flood setup was used to allow porosity measurements by gas expansion method, then pulse decay permeability measurements, and fluid injection during the leak-off process. Nitrogen was used for gas expansion and permeability measurements, while 5 wt% KCl brine was used as representative of the leak-off fracturing fluid. The fracturing fluid was injected under a constant pressure gradient (300 in the case of sandstone cores and 1500 psi in the case of shale cores. After removing the pressure gradient, gas permeability was measured at different soaking times. Computed tomography (CT) was used to scan the cores during the experiment to observe the propagation of fracturing fluid in the core with time.〈/p〉 〈p〉The results show that the regained permeability for sandstone formation was 60% of its initial value directly after the leak-off stage. Then, the regained permeability decreased with increasing the soaking time 38% of its initial value after the core completely invaded with leak-off fluid. The propagation rate of water saturation front from CT-scan data decreased with time until reaching the core outlet. The regained permeability on shale cores was 15% of its initial value and decreased with soaking time, due to depressed relative permeability curve on this tight pore-space cores.〈/p〉 〈p〉This study addresses the mechanism of production enhancement or reduction as a result of the soaking process for shale and tight sandstone formations.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Arash Azamifard, Fariborz Rashidi, Mohammad Ahmadi, Mohammadreza Pourfard, Bahram Dabir〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Different sources of data are used to construct a reliable model of reservoir for oil/gas production. This model ought to be matched with the production history of reservoir and also show reliable predictions for future performance. To this end, permeability modeling (characterization of heterogeneity) is crucially important which is proved to be done by Multiple Point Statistics (MPS) recently. Furthermore, deep learning methods are massively used as a promising tool for regression applications. In this study, one MPS method is employed for generating the reservoir realizations. Realizations, alongside their simulation outputs, are utilized for training a convolutional deep network. In this manner, MPS is joined with deep learning to find the most appropriate realization(s) of the reservoir based on the fluid flow simulation. Moreover, unseen MPS realizations as well as another MPS realizations are used to verify the selection ability of trained network. The detailed architecture of convolutional network is illustrated in this study.〈/p〉 〈p〉The purpose of training this network and combination with MPS is to generate the matched realization(s) in history period that also show acceptable reservoir behavior in the future times of reservoir simulation. After training, the actual production data of selected realizations are obtained by simulation the reservoir for history and also future times. The results show that selected realizations efficiently capture the trend of reference behavior. Although these realizations lack identical permeability values, they have same texture of permeability (permeability heterogeneity). Meanwhile, they show acceptable match in reservoir simulation outputs. By proposed workflow, the uncertainty of permeability modeling is considered more exhaustively. It is done by selecting the realizations from enormous possible realizations dataset and providing a deep learning tool which is capable for screening quite large number of realizations. Interesting finding is satisfactory behavior of realization(s) in both history and future periods of reservoir performance.〈/p〉 〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0920410519305467-fx1.jpg" width="351" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉