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  • Articles  (17)
  • Royal Society Open Science  (16)
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  • Natural Sciences in General  (17)
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  • Articles  (17)
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  • Natural Sciences in General  (17)
  • Biology  (14)
  • 1
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    Rheological properties and damage-control mechanism of oil-based drilling fluid with different types of weighting agents (2018)
    Royal Society
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    Publication Date: 2018-07-26
    Description: The great amount of solid particles contained in a weighting agent is a major cause of the problems in both rheology properties and damage control mechanism of an oil-based drilling fluid (OBM). Therefore, a proper type of weighting agent can be a solution for the application of OBM. In this study, three weighting agents that have been commonly used with OBM, namely, standard barite, submicron barite and superfine manganese ore, are studied. Rheological properties of OBM and the degree of formation damage are assessed with regard to the three weighting agents. The agents are also studied in aspects of particle size, micromorphology, filtration loss and wall-building property, acid dissolution efficiency of mud cake, lubricity and sedimentation stability to analyse the effects of the agents on rheological properties and the degree of damage as well as to figure out the mechanism of rheology control and damage control. For the OBM, there is a mutual effect between rheological stability and the degree of damage. In consideration of the agents' properties, we can enhance the rheological stability of the OBM and control the degree of formation damage by properly selecting particle size, using acid-soluble materials and forming the mud cake with ultra-low permeability that can easily be cleared away.
    Keywords: energy, chemical engineering
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 2
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    Corrosion-resistant systems of formate packer fluid for G3/N80/TP110SS pipes at high temperature, high pressure and high H2S/CO2 ratios (2018)
    Royal Society
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    Publication Date: 2018-07-26
    Description: A series of corrosion problems caused by high-temperature, high-pressure and high-acid gas environments has been an issue in oil and gas production for a long time. During the development of a high-acid gas field, the petroleum pipe is subjected to many aspects of corrosion, and the corrosion mechanism is complicated by the condition of the coexistence of H 2 S/CO 2 . Based on the study of the corrosion problem associated with the formate packer fluid in Southwest China, three kinds of steels were studied for corrosion prevention in the alloy G3/N80 steel/TP110SS steel. The study shows that the corrosion rate of the formate packer fluid is low, but corrosion is severe in environments characterized by high temperatures, high pressures and high-acid gas contents. Based on the consideration of cost and the difficulty of realization, an anti-corrosion system was constructed based on the existing packer fluid, mainly through the introduction of a variety of anti-corrosion additives. Through the selection of various additives and corrosion experiments, a corrosion protection system of formate packer fluid was developed. Corrosion tests show that the corrosion rate of the system must be less than 0.076 mm yr –1 to achieve the purpose of corrosion protection. The formate packer fluid with corrosion protection can meet the needs of the current application.
    Keywords: materials science, energy, chemical engineering
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
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  • 3
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    Controlling complex networks (2016)
    Royal Society
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    Publication Date: 2016-04-28
    Description: Recent works revealed that the energy required to control a complex network depends on the number of driving signals and the energy distribution follows an algebraic scaling law. If one implements control using a small number of drivers, e.g. as determined by the structural controllability theory, there is a high probability that the energy will diverge. We develop a physical theory to explain the scaling behaviour through identification of the fundamental structural elements, the longest control chains (LCCs), that dominate the control energy. Based on the LCCs, we articulate a strategy to drastically reduce the control energy (e.g. in a large number of real-world networks). Owing to their structural nature, the LCCs may shed light on energy issues associated with control of nonlinear dynamical networks.
    Keywords: mathematical physics, complexity
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
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  • 4
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    Numerical and experimental study of pyrophoric activated metal Mg surface combustion characteristics (2018)
    Royal Society
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    Publication Date: 2018-05-17
    Description: The combustion of multi-hole pyrophoric activated metal is solid combustion and the combustion mechanism is quite complex, which is a difficult problem to be solved. Once the pyrophoric activated metal is exposed to air, the oxygen diffuses to the interior of the activated metal within plenty of holes and reacts with it, which enlarges the contact area with oxygen. Consequently, the whole combustion is vigorous and the temperature rises rapidly. To study the combustion mechanism of the chaff, the surface heat balance equation is established in this work by taking Mg as the activated metal. To solve this equation, the chaff adiabatic wall temperature distribution is computed by computational fluid dynamics in the presence of high-speed airflow. Then, the chaff surface temperature distribution is obtained by solving the heat balance equations. Finally, numerical and experimental results obtained via an infrared thermal imager are compared to demonstrate the effectiveness of the established equation.
    Keywords: thermodynamics, spectroscopy, chemical physics
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
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  • 5
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    Gene delivery ability of polyethylenimine and polyethylene glycol dual-functionalized nanographene oxide in 11 different cell lines (2017)
    Royal Society
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    Publication Date: 2017-10-26
    Description: We recently developed a polyethylenimine (PEI) and polyethylene glycol (PEG) dual-functionalized reduced graphene oxide (GO) (PEG–nrGO–PEI, RGPP) for high-efficient gene delivery in HepG2 and Hela cell lines. To evaluate the feasibility and applicability of RGPP as a gene delivery carrier, we here assessed the transfection efficiency of RGPP on gene plasmids and siRNA in 11 different cell lines. Commercial polyalkyleneimine cation transfection reagent (TR) was used as comparison. In HepG2 cells, RGPP exhibited much stronger delivery ability for siRNA and large size plasmids than TR. For green fluorescent protein (GFP) plasmid, RGPP showed about 47.1% of transfection efficiency in primary rabbit articular chondrocytes, and about 27% of transfection efficiency in both SH-SY5Y and A549 cell lines. RGPP exhibited about 37.2% of GFP plasmid transfection efficiency in EMT6 cells and about 26.0% of GFP plasmid transfection efficiency in LO2 cells, but induced about 33% of cytotoxicity in both cell lines. In 4T1 and H9C2 cell lines, RGPP had less than 10% of GFP plasmid transfection efficiency. Collectively, RGPP is a potential nano-carrier for high-efficiency gene delivery, and needs to be further optimized for different cell lines.
    Keywords: biomaterials
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
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  • 6
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    Photocatalytic degradation of sulfamethazine in aqueous solution using ZnO with different morphologies (2018)
    Royal Society
    Details
    Publication Date: 2018-04-12
    Description: In this study, photocatalytic experiments of 20 mg l –1 sulfamethazine (SMN) in aqueous solution containing ZnO with different morphologies, tetra-needle-like ZnO (T-ZnO), flower-like ZnO (F-ZnO) and nanoparticles ZnO (P-ZnO), were performed. The results indicated that photocatalytic degradation of SMN was effective and followed the pseudo-first-order reaction, but the degree of SMN mineralization showed obvious differences using ZnO with different shapes. After 12 h irradiation, 86%, 71% and 50% of the initial total organic carbon was eliminated in SMN suspension containing T-ZnO, F-ZnO and P-ZnO, respectively. The release ratio of sulfur was close to 100% in the presence of T-ZnO, but reached to 86% and 67% in the presence of F-ZnO and P-ZnO, respectively. The release ratio of nitrogen was about 76%, 63% and 40% using T-ZnO, F-ZnO and P-ZnO as photocatalyst, respectively. The morphology of ZnO played an important role in determining its catalytic activity. Seven intermediates were observed and identified in the UV/T-ZnO reaction system by LC-MS/MS analysis, and a possible degradation pathway was proposed.
    Keywords: nanotechnology, photochemistry, environmental chemistry
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
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  • 7
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    Carbon nanotube-based flexible electrothermal film heaters with a high heating rate (2018)
    Royal Society
    Details
    Publication Date: 2018-06-07
    Description: High-performance, flexible film heaters with carbon nanotube transparent conducting films are easily fabricated by both a rod-coating method and a spraying method. The main conclusion we have reached is that the film demonstrates a heating rate of 6.1°C s –1 at 35 V and sheet resistance as low as 94.7 sq –1 with 72.04% optical transmittance at a wavelength of 550 nm by the spraying method after a series of post-treatment processes with acid and distilled water. Then, we adopt a mathematical method of nonlinear fitting to simulate the collected experimental data and the functions effectively. Furthermore, through analysis of the formula, the correlation between temperature and time is well explained. Therefore, carbon nanotube-based, flexible, transparent heaters exhibit high electrothermal performance and are expected to find different applications, e.g. various functional devices such as heating materials, heatable smart windows or dining tables.
    Keywords: materials science, nanotechnology, chemical physics
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
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  • 8
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    Expression and function of ATP-dependent potassium channels in zebrafish islet {beta}-cells (2017)
    Royal Society
    Details
    Publication Date: 2017-02-10
    Description: ATP-sensitive potassium channels (K ATP channels) are critical nutrient sensors in many mammalian tissues. In the pancreas, K ATP channels are essential for coupling glucose metabolism to insulin secretion. While orthologous genes for many components of metabolism–secretion coupling in mammals are present in lower vertebrates, their expression, functionality and ultimate impact on body glucose homeostasis are unclear. In this paper, we demonstrate that zebrafish islet β-cells express functional K ATP channels of similar subunit composition, structure and metabolic sensitivity to their mammalian counterparts. We further show that pharmacological activation of native zebrafish K ATP using diazoxide, a specific K ATP channel opener, is sufficient to disturb glucose tolerance in adult zebrafish. That β-cell K ATP channel expression and function are conserved between zebrafish and mammals illustrates the evolutionary conservation of islet metabolic sensing from fish to humans, and lends relevance to the use of zebrafish to model islet glucose sensing and diseases of membrane excitability such as neonatal diabetes.
    Keywords: physiology, cellular biology, evolution
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
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  • 9
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    Exploring the difference in xerogels and organogels through in situ observation (2018)
    Royal Society
    Details
    Publication Date: 2018-02-01
    Description: Solvent–gelator interactions play a key role in mediating organogel formation and ultimately determine the physico-chemical properties of the organogels and xerogels. The ethanol organogels of 1,4-bis[(3,4,5-trihexyloxy phenyl)hydrazide]phenylene (TC6) were investigated in situ by FT-IR, Raman and fluorescence spectra, and XRD, and it was confirmed that the intermolecular interaction and aggregation structure of TC6 ethanol organogels were quite different from those of xerogels. Simultaneously, unprecedented phase transition from organogel to suspension upon heating was observed in ethanol organogel, and the suspension phase exhibited lytropic liquid crystalline behaviour with a rectangular columnar structure. This study may open the possibility to design new gelators with a new dimension of versatility.
    Keywords: organic chemistry, supramolecular chemistry
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
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  • 10
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    Ratiometric fluorescent test paper based on silicon nanocrystals and carbon dots for sensitive determination of mercuric ions (2018)
    Royal Society
    Details
    Publication Date: 2018-06-28
    Description: Classical dye absorption-based pH test papers are widely used to measure the degree of acidity of media for quantification or semi-quantification by the observation of the naked eye on the variation of colour. However, it remains a challenging task to extend portable and cheap methods to a wide range of analytes for accurate quantification. Here, we report a dosage-sensitive test paper for the assay of mercury ions (Hg 2+ ) with wide colour evolution. The ratiometric fluorescent probe was prepared by mixing blue-emission silicon nanocrystals (Si NCs) and red-emission carbon dots (r-CDs). The Si NCs serve as the reaction site and the r-CDs as the internal reference. Upon the addition of Hg 2+ , the blue fluorescence of the Si NCs was quenched, while the red fluorescence of the r-CDs remained constant, resulting in the consecutive fluorescence colour changes from blue to orange red. The probe demonstrates high selectivity and sensitivity of the visualization assay of Hg 2+ with a detection limit of 7.63 nM. Moreover, we printed the ratiometric fluorescence probe result onto a piece of filter paper to prepare a test paper, which represents an on-site, sensitive, rapid and cost-effective method for the visual determination of Hg 2+ by the naked eye.
    Keywords: analytical chemistry
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
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