ALBERT

Description: 〈p〉Publication date: Available online 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): S. Monzani, A. Andreazza, M. Citterio, P. Fontana, M. Ianna, T. Lari, V. Liberali, F. Ragusa, C. Sbarra, A. Sidoti, A. Stabile〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Monochromatic X and gamma rays are a standard calibration tool for semiconductor detector. For finely segmented pixel detectors, like the ones foreseen for HL-LHC detector upgrades, the single pixel spectrum is affected by charge sharing across nearby pixels, due to diffusion and the finite range of photoelectrons, resulting in a low energy continuum below the photoelectric peak. In this paper a systematic simulation study will be presented. The shape of the transition between the photoelectric peak and the continuum is determined by diffusion and needs to be unfolded for a correct estimation of the energy resolution. Simulation results are compared with data collected with different high-resistivity CMOS devices with 50 × 250 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mi mathvariant="normal"〉μ〈/mi〉〈/math〉m〈sup〉2〈/sup〉 pixel size and photon energies between 13 and 60 keV. They show a good agreement, highlighting the potential usage of the whole single pixel spectrum to derive device characteristics.〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 562〈/p〉 〈p〉Author(s): Parisa Moazzam, Giorgio Luciano, Amir Razmjou, Ehsan Akbari, Pavel G. Ul’yanov, Soumitro Mahanty〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The degree of available energy on a surface determines how a surface interacts with its surrounding environment such as corrosion. Current approaches to protection of Aluminum surfaces from corrosion mainly focus on adding an organic or inorganic layer to either act as a barrier from oxidant or scarifying to inhibit the corrosion. Altering the surface energy of Al on a molecular level is another alternative approach to efficiently modify the Al surface without the need for another thick expensive protective or scarifying materials. Herein, an attempt was made to understand how a molecular scale energy alteration improves the anticorrosion behavior of an aluminum surface. Two different surface engineering alteration strategies have been discussed; termed ALOSH and ALTSH modification. A variety of analytical instruments, i.e., FTIR, EDAX, XPS, SEM, AFM, WCA, and SFE measurement were used to systematically characterize the samples. Electrochemical impedance spectroscopy revealed that there are different resistances after the surface modifications. The trapping air resistance appeared in ALTSH is approximately 2.4 and 36 times higher than that of ALOSH and bare samples, respectively. The potentiostat analysis results showed that the mili inch per year value of coating for ALTSH was 0.012 while that of ALOSH was 0.507. It was also found that the low surface energy alteration without using inert molecules is not enough to render corrosion inhibition property, as it needs to have a protective energy barrier with no or minimal active electrochemical behavior.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718311294-ga1.jpg" width="320" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 31 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): K. Dropiewski, A. Minns, M. Yakimov, V. Tokranov, P. Murat, S. Oktyabrsky〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Picosecond timing of energetic charged particles and photons is a challenge for many high-energy physics and medical applications. InAs Quantum Dots (QDs) embedded in GaAs matrix are expected to have singular scintillation properties. The advantages come from highly efficient energy conversion, as well as from fast electron capture and radiative recombination in QDs. We present design considerations and demonstration of an ultrafast, high photon yield room-temperature semiconductor scintillator. Due to the high refractive index of GaAs, the scintillator is fabricated in the form of a 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mn〉20〈/mn〉〈mspace width="1em"〉〈/mspace〉〈mi mathvariant="normal"〉μ〈/mi〉〈mi mathvariant="normal"〉m〈/mi〉〈/math〉 thick planar waveguide with an integrated InGaAs photodiode. QD luminescence of about 60% efficiency at room temperature has been shown, and modal attenuation stabilized at 1 cm〈sup〉−1〈/sup〉. Scintillation responses from 5.5 MeV alpha particles show an extremely fast decay time of 280 ps, a collection efficiency of 11% and a time resolution of 60 ps. This data confirms the unique potential properties of this scintillation detector.〈/p〉〈/div〉

Description: 〈p〉Publication date: 21 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 915〈/p〉 〈p〉Author(s): Jingyu Tang, Changdong Deng, Xi Wu, Shuai Li, Yuwen Wu, Wen Kang, Xiyin Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents the design and prototyping of novel structure magnets–simplified multipole magnets, one octupole and one dodecapole. The field measurements of the prototypes show very good agreement with the numerical field calculations. The octupole prototype can produce either an anti-symmetric or a symmetric field distribution. Magnets with this novel structure can supply much higher saturation fields, e.g. doubled pole-gap strength of 0.6 T for the dodecapole prototype. The intrinsic field errors for the integrated field distribution are within 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si15.gif"〉〈mo〉±〈/mo〉〈/math〉1% for a rectangular shape of good field region, which are acceptable for some applications such as beam spot uniformization. Some key technical issues of building the magnets are also discussed. The success of the prototyping will pave the way for applications of the magnet family.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): Noriaki Kawaguchi, Go Okada, Kentaro Fukuda, Takayuki Yanagida〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We have tested high-temperature responses of prototype neutron detectors equipping Ce-doped lithium silicate glass (GS20), LiCaAlF〈sub〉6〈/sub〉:Ce, LiCaAlF〈sub〉6〈/sub〉:Eu, LiCaAlF〈sub〉6〈/sub〉:Ce, Na, and LiCaAlF〈sub〉6〈/sub〉:Eu, Na. These detectors were prepared by coupling of the scintillators to a photomultiplier tube (PMT) for high-temperature environments (R1288, Hamamatsu). In the pulse height spectra under thermal neutron irradiation in the temperature range from 25 °C to 150 °C, peak heights of all the samples decreased with increasing temperatures. The decreasing rates for the peak heights of LiCaAlF〈sub〉6〈/sub〉 scintillators were lower than that of GS20. The LiCaAl〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈msub〉〈mrow〉〈mi mathvariant="normal"〉F〈/mi〉〈/mrow〉〈mrow〉〈mn〉6〈/mn〉〈/mrow〉〈/msub〉〈/math〉scintillators can be used in the temperature range from 25 °C to 150 °C.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): A. Loi, A. Lai, G.F. Dalla Betta, R. Mendicino, S. Vecchi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The experimental conditions in future High Luminosity LHC experiments require new detector systems with increased performances compared to the current state of the art. In this context, increasing spacial resolution and including time measurement with a resolution of less than 50 ps for particle tracking systems can avoid false track reconstruction due to event pile up. For this kind of future tracking detectors the 3D silicon sensor technology appears as a good option. In this context the TIMESPOT initiative was launched. Concerning the development of the sensor, different geometrical solutions have been explored and simulated to optimize the timing response of the single pixel sensor using Sentaurus TCAD. The configuration with the best electric field characteristics for timing was selected for signal simulation. In order to compensate the very time-consuming behavior of TCAD simulations, a faster charge transport simulator with TCAD and Geant4 support is under development. Further sensor configurations, including a first primitive capacitive and resistive load, were also simulated and evaluated. This paper shows a general overview of the project with particular attention to the silicon sensor development. First results are presented.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 913〈/p〉 〈p〉Author(s): S. Mehdi Hashemi, Ali Negarestani〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, the performance of two GEM-type structures for the detection of alpha particle tracks in gaseous detectors based on SQS mode is presented. The operation of these structures was investigated in the presence of air, pure argon and P10 gas. By increasing the applied voltage to GEM-type plates beyond a certain value, each GEM-type’s through-hole individually entered to the SQS mode, when detector operated in the P10 gas. This mode was followed by the appearance of visible streamers in the space of holes exposed to alpha radiation. Two types of Thick Gas Electron Multipliers (TGEM) and Electron Multiplier Assemblies (EMA) with different geometries, as well as a cascade configuration of EMAs, were designed and constructed. Depending on the hole diameters in these structures, the location of the input beams can be determined optically with a specific resolution.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): G. Silvestre, on behalf of FOOT collaboration〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The goal of the FOOT (FragmentatiOn Of Target) experiment is to measure the fragmentation cross section of protons into H, C, O targets at beam energies of interest for hadrontherapy (50–250 MeV for protons and 50–400 MeV/u for Carbon ions) (Tommasino et al., 2015 [1]; FOOT CDR Conceptual Design, 0000 [2]). Given the short range of the fragments, an inverse kinematic approach has been chosen, hence requiring precise tracking capabilities for charged ions. One of the foreseen experiment subsystems will be the MSD (Microstrip Silicon Detector), composed of three 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mi〉x〈/mi〉〈/math〉–〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si2.gif"〉〈mi〉y〈/mi〉〈/math〉 measuring planes. In this work we evaluate the suitability of standard double-sided microstrip detectors, coupled to an high dynamic range readout chip, to be used for this task. The results about cluster signal, signal/noise, and dynamic range of readout chip are encouraging, and confirm the suitability of this class of sensors to be used in the FOOT experiment.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 919〈/p〉 〈p〉Author(s): Xiurong Li, Huihai He, Gang Xiao, Xiong Zuo, Shaohui Feng, Lingyu Wang, Cong Li, Mohsin Saeed, Zhen Cao, Xiangdong Sheng, Ning Cheng, for the LHAASO collaboration〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, novel methods are presented to measure the optical properties of the cylindrical water Cherenkov detector with high-reflectivity and diffuse reflection dominated Tyvek material as the inner surface. The mean transmission distance of photons between each reflection in the cylindrical water Cherenkov detector (the mean step length), is constant when there is a sufficient number of photons with random directions in the tank. The time distribution of the photons collected by the photomultiplier tube (PMT) in the water Cherenkov detector is approximately exponential, and the decay factor of the time distribution is determined by the absorption length of photons in the water, the reflectivity of the inner Tyvek surface, the mean step length of photons reflected in the tank, and the ratio of reflective Tyvek area to the total inner surface area. By considering the principles of photon propagation in the water Cherenkov detector, we developed novel methods to measure the water absorption length, Tyvek reflectivity, and mean step length of photons in the tank. The water absorption length and Tyvek reflectivity can be measured simultaneously by changing the height of the water, while the step length and Tyvek reflectivity in air can be measured simultaneously by changing the area of Tyvek, and the mean step length of photons can also be measured even all other parameters unknown. The proposed novel methods are supported by the deduction of formulae and verified by GEANT4 simulations and the prototype experiment.〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 561〈/p〉 〈p〉Author(s): Corina L. Reichert, Hanna Salminen, Gabriela Badolato Bönisch, Christian Schäfer, Jochen Weiss〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The concentration ratio of binary surfactant systems can alter the interfacial layer properties, and consequently affect emulsion stability. To study the effect of varying concentration ratios (〈em〉r,〈/em〉 % w/w) of interfaces containing 〈em〉Quillaja〈/em〉 saponins and other naturally occurring food-grade surfactants on their emulsifying properties, we evaluated particle size, ζ-potential, and appearance of 10% oil-in-water emulsions (pH 7) stabilized by 〈em〉Quillaja〈/em〉 saponin - protein or 〈em〉Quillaja〈/em〉 saponin - lecithin mixtures. 〈em〉Quillaja〈/em〉 saponin - Na-caseinate mixtures (〈em〉r〈/em〉 = 0.3:0.2, 0.2:0.3, and 0.1:0.4) formed small emulsion droplets (d〈sub〉43〈/sub〉: 0.2 – 0.3 μm), whereas at 〈em〉r〈/em〉 = 0.4:0.1, the emulsions contained micron-sized droplets (d〈sub〉43〈/sub〉: 1.217 ± 0.558 μm). Emulsions formed by 〈em〉Quillaja〈/em〉 saponin - pea protein mixtures flocculated at 〈em〉r〈/em〉 = 0.3:2.0, 0.2:3.0, and 0.1:4.0. In contrast, 〈em〉Quillaja〈/em〉 saponin - rapeseed lecithin or egg lecithin mixtures were able to generate small emulsion droplets (d〈sub〉43〈/sub〉: 0.2 – 0.5 μm) at all tested concentration ratios. The formation of stable emulsions using binary mixtures of naturally occurring emulsifiers was more dependent on the concentration ratio of the proteins than lecithins, indicating that the interfacial behavior of 〈em〉Quillaja〈/em〉 saponins is more sensitive to the presence of proteins. This was attributed to attractive molecular interactions yielding complexes at interfaces and/or in the continuous phase. This study shows that food-grade binary surfactant mixtures can be used to form stable emulsions with properties being tunable by altering the mixing ratios between surfactants.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571831522X-ga1.jpg" width="429" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 561〈/p〉 〈p〉Author(s): Li Wang, Jingyi Wang, Chi He, Wei Lyu, Wenlong Zhang, Wei Yan, Liu Yang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To improve the biochar’s adsorption performance towards phosphate as well as to endow the biochar with magnetic property, novel rare earth element doped magnetic biochars, Ce/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC and La/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC, were prepared by separately co-precipitating cerium (Ce) and lanthanum (La) with FeCl〈sub〉3〈/sub〉, FeCl〈sub〉2〈/sub〉 and biochar. For comparison, Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC without doping Ce or La was also synthesized. The characterization results indicated that Ce and La ions were successfully doped into the magnetite. The La/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC had higher magnetic saturation and point of zero charge than Ce/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC. A series of batch experiment results demonstrated that the phosphate adsorption capacity of biochar has been greatly improved after Ce or La doping, especially La. The phosphate adsorption capacity of La/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC was 20.5 mg/g at pH 6.5, which was 1.6 and 2.9 times than that of Ce/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC and Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC, respectively. The adsorption kinetics and isotherms of phosphate onto La/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC and Ce/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC were best fitted by the pseudo-second order and Freundich model, respectively, indicating that the adsorption process was a multilayer process and controlled by chemical reaction. The combined results of batch experiments and physiochemical analyses revealed that the possible mechanisms were the formation of inner-sphere complex at neutral conditions and electrostatic attraction between positively charged adsorption sites and phosphate under acid conditions. The enhanced phosphate adsorption performance and endowed magnetic property indicated La/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC could be used as a promising adsorbent in phosphate removal.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718312615-ga1.jpg" width="455" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): N. Cartiglia, R. Arcidiacono, M. Ferrero, M. Mandurrino, H.-F.W. Sadrozinski, V. Sola, A. Staiano, A. Seiden〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The combination of precision space and time information in particle tracking, the so called 4D tracking, is being considered in the upgrade of the ATLAS, CMS and LHCb experiments at the High-Luminosity LHC, set to start data taking in 2024-25. Regardless of the type of solution chosen, space–time tracking brings benefits to the performance of the detectors by reducing the background and sharpening the resolution; it improves tracking performances and simplifies tracks combinatorics. Space–time tracking also allows investigating new physics channels, for example it opens up the possibilities of new searches in long-living particles by measuring accurately the time of flight between the production and the decay vertexes. The foreseen applications of 4D tracking in experiments with very high acquisition rates, for example at HL-LHC, add one more dimension to the problem, increasing dramatically the complexity of the read-out system and that of the whole detector design: we call 5D tracking the application of 4D tracking in high rate environments.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 913〈/p〉 〈p〉Author(s): George Kitis, Vasilis Pagonis〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Experimental Thermoluminescence (TL) glow curves for most dosimetric materials are composites, consisting of weakly or strongly overlapping peaks. The ability to discriminate between two overlapping peaks defines the resolution of a TL glow curve. Although the concept of resolution has been defined and used widely in many areas of science, there have been no previous attempts to define and study the resolution of overlapping TL peaks. In this work the resolution parameter R is defined in terms of the geometrical characteristics of TL peaks. A large number of TL glow curves consisting of two peaks were numerically evaluated for various degrees of overlapping between them. These numerically generated glow curves were analyzed by a computerized glow curve deconvolution analysis, in order to determine the reliability of the deconvolution results as a function of the resolution parameter R.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): S. Zhao, G. Lioliou, S. Butera, M.D.C. Whitaker, A.M. Barnett〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A Commercial-Off-The-Shelf (COTS) 4H-SiC p-n photodiode (sold as a UV detector) was investigated as detector of electrons (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si34.gif"〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉β〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈/mrow〉〈/msup〉〈/math〉 particles) over the temperature range 100 °C to 20 °C. The photodiode had an active area of 0.06 mm〈sup〉2〈/sup〉. The currents of the photodiode were measured in dark condition and under the illumination of a 〈sup〉63〈/sup〉Ni radioisotope 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si34.gif"〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉β〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈/mrow〉〈/msup〉〈/math〉 particle source (endpoint energy = 66 keV). The photodiode was then coupled to a custom-made low-noise charge-sensitive preamplifier to make a direct detection particle counting electron spectrometer. 〈sup〉63〈/sup〉Ni 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si34.gif"〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉β〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈/mrow〉〈/msup〉〈/math〉 particle spectra were accumulated with the spectrometer operating at temperatures up to 100 °C. The quantum efficiency of the photodiode as well as the spectrum expected to be detected were calculated via Monte Carlo simulations produced using the CASINO computer program. Comparisons between the simulated and detected 〈sup〉63〈/sup〉Ni 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si34.gif"〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉β〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈/mrow〉〈/msup〉〈/math〉 particle spectra are presented. The work was motivated by efforts to apply COTS technologies to develop low-cost space science instrumentation; a low-cost electron spectrometer of this type could be included on a university-led CubeSat mission for space plasma physics and magnetosphere experiments.〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): M. Sharma, J. Nattress, I. Jovanovic〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Design of deuterium–tritium (DT) neutron generator facilities requires a careful assessment of radiation shielding. In the models of such facilities an isotropic distribution of neutron flux produced by the neutron generator is usually assumed. However, prior studies have shown that neutron flux surrounding the neutron generator can be anisotropic. This anisotropy results mostly from the design of the generator tube, as well as the angular dependence of DT fusion reaction cross section. In this work, the angular neutron flux was measured for a standard commercially available DT generator (Thermo Fisher Scientific, Model P211) using an organic scintillator and a significant degree of anisotropy was confirmed to exist. The experimentally determined flux was then used in Monte Carlo simulations to examine the impact of anisotropy on the effectiveness of radiation shielding. Although the shielding effectiveness is not considerably affected by the anisotropy, the dose rates in air around the unshielded generator can be significantly different from those predicted when an assumption of isotropic flux is made. These considerations need to be included in modeling of the dose rate around the generator in neutron generator facilities that employ typical neutron generators, which exhibit some degree of anisotropy in neutron flux.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): David Longuevergne〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The different processes at the origin of the dependence of the surface resistance with the RF magnetic field are still not fully understood. Several models have emerged since many years to explain the drop of the quality factor 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si96.gif"〉〈msub〉〈mrow〉〈mi〉Q〈/mi〉〈/mrow〉〈mrow〉〈mn〉0〈/mn〉〈/mrow〉〈/msub〉〈/math〉 (commonly called Q-drop) of a superconducting cavity versus the accelerating gradient. Experimental data are commonly fitted by applying a coarse approximation to convert the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si96.gif"〉〈msub〉〈mrow〉〈mi〉Q〈/mi〉〈/mrow〉〈mrow〉〈mn〉0〈/mn〉〈/mrow〉〈/msub〉〈/math〉 (a global property) into a surface resistance (local property). Extracting accurately the surface resistance from experimental data requires to take into account the RF field distribution over the accelerating structure contrary to what is commonly done in the community. Assuming a field dependent surface resistance does not allow anymore to use the well-known formula 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈msub〉〈mrow〉〈mi〉Q〈/mi〉〈/mrow〉〈mrow〉〈mn〉0〈/mn〉〈/mrow〉〈/msub〉〈mo〉=〈/mo〉〈mi〉G〈/mi〉〈mo〉∕〈/mo〉〈mi〉R〈/mi〉〈/math〉〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si4.gif"〉〈msub〉〈mrow〉〈/mrow〉〈mrow〉〈mi mathvariant="normal"〉s〈/mi〉〈/mrow〉〈/msub〉〈/math〉. This paper gives a procedure to perform an accurate conversion of the quality factor measured during a cavity test into a surface resistance to avoid any error in the evaluation of fitting parameters due to the geometry.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): S. Roy, S. Rudra, S. Shaw, S. Chatterjee, S. Chakraborty, R.P. Adak, S. Biswas, S. Das, S.K. Ghosh, S.K. Prasad, S. Raha〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Study of the stability of gain and energy resolution for a triple GEM detector has been performed under continuous radiation of X-ray with high rate, using premixed gas of Argon and CO〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈msub〉〈mrow〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈/math〉 in 70/30 ratio and conventional NIM electronics. A strong 〈sup〉55〈/sup〉Fe X-ray source is used for this study. The novelty of this study is that for the stability test same source is used to irradiate the GEM chamber and to monitor the spectrum. The radiation is not collimated to a point but exposed to a larger area. Effect of temperature and pressure on these parameters are also studied. The detail method of measurement and the first test results are presented.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): T. Washimi, M. Kimura, M. Tanaka, K. Yorita〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A two-phase argon detector has high discrimination power between electron recoil and nuclear recoil events based on the pulse shape discrimination and the ionization/scintillation ratio (S2/S1). This character is very suitable for the dark matter search to establish the low background experiment. However, the basic properties of S2/S1 of argon are not well known, as compared with xenon. We report the evaluation of S2/S1 properties with a two-phase detector at drift-fields of 0.2–3.0 kV/cm. Finally, the discrimination power against electron recoil background of S2/S1 is discussed.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): A. Natochii, L. Burmistrov, F. Addesa, O. Bezshyyko, D. Breton, V. Chaumat, G. Cavoto, S. Dubos, Y. Gavrikov, F. Iacoangeli, J. Maalmi Di Bello, S. Montesano, V. Puill, R. Rossi, W. Scandale, A. Stocchi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A method to characterise the quality of a fused silica surface using a 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si4.gif"〉〈mi〉β〈/mi〉〈/math〉-source is presented. Two fused silica bars (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si2.gif"〉〈mn〉5〈/mn〉〈mo〉×〈/mo〉〈mn〉10〈/mn〉〈mo〉×〈/mo〉〈mn〉400〈/mn〉〈mspace width="1em"〉〈/mspace〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉mm〈/mi〉〈/mrow〉〈mrow〉〈mn〉3〈/mn〉〈/mrow〉〈/msup〉〈/math〉) were fabricated for the Cherenkov detector for proton Flux Measurement installed at vacuum chamber of the Super Proton Synchrotron at CERN. The resolution of such device is defined by the collection efficiency of the Cherenkov light, which is produced by relativistic charged particles in the fused silica. Thus, the surface quality of the radiator should be as good as possible to avoid light losses. The method is based on the scanning of the radiator surface with a 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈msup〉〈mrow〉〈/mrow〉〈mrow〉〈mn〉90〈/mn〉〈/mrow〉〈/msup〉〈mi〉S〈/mi〉〈mi〉r〈/mi〉〈/math〉 radioactive source and measurements of the Cherenkov light rate, detected by a PMT attached to the quartz bars. The data have been compared with a Monte-Carlo simulation, providing an estimation of the radiator’s probability of the total internal reflection and inefficient area at the edges of the bars.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): M. Usami, G. Boca, P.W. Cattaneo, M. De Gerone, F. Gatti, M. Nakao, M. Nishimura, W. Ootani, M. Rossella, Y. Uchiyama〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We studied the impact of radiation damage on scintillation counters read out by six SiPMs connected in series focusing on their time resolution. Six SiPMs from AdvanSiD were irradiated step by step with a 37 MBq 〈sup〉90〈/sup〉Sr source. At the integrated dose expected at the end of the MEG II experiment, the time resolution at 30 °C was measured to be worse by 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si29.gif"〉〈mo〉∼〈/mo〉〈/math〉29%. However, the deterioration is found to be reduced to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si29.gif"〉〈mo〉∼〈/mo〉〈/math〉6% at 10 °C since thermal dark noise is suppressed. We also tested the effect of connecting in series differently damaged SiPMs. We observed a position dependence of the time center in a counter, which worsened the time resolution.〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): Haeryong Yang, Gyujin Kim, Heung-Sik Kang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The hard X-ray free electron laser at the Pohang Accelerator Laboratory (PAL-XFEL) in the Republic of Korea achieved a saturation of free electron laser (FEL) beam at 14.5 keV with an unprecedented intensity of 2.8E+11 photons per pulse. Successfully maintaining a very small emittance electron beam along the 700-m long linac, maximizing the spectral overlap of undulator radiation along the undulator line by the undulator radiation spectrum analysis, and optimal matching between the electron beam and photon beam through the 100-m long undulator line have allowed saturation and reliable operation of a 14.5 keV FEL beam.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): F. Abudinen, K. Ackermann, P. Ahlburg, M. Albalawi, O. Alonso, L. Andricek, R. Ayad, V. Babu, Y. Bai, T. Bilka, R. Blanco, M. Boronat, A. Bozek, C. Camien, A. Caldwell, V. Chekelian, B. Deschamps, A. Dieguez, J. Dingfelder, Z. Doležal〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Belle II experiment will run with a reduced beam asymmetry and a factor of 40 higher instantaneous luminosity compared to the Belle experiment. To cope with this and to be able to perform high precision vertex measurements for charge conjugation parity violating processes, a pixel detector based on DEPFET technology will be installed in the center of Belle II. Its basic properties and the DAQ chain are presented in this article.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): Zdzisław Dębicki, Karol Jędrzejczak, Jacek Karczmarczyk, Marcin Kasztelan, Ryszard Lewandowski, Jerzy Orzechowski, Jacek Szabelski, Maria Szeptycka, Przemysław Tokarski〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉We performed measurements of thermal and non-thermal neutron flux in underground laboratories in Gran Sasso, Italy and in Slanic Prahova, Romania. The measurements were made with a set of helium counters: bare for thermal neutrons and covered by blocks of moderator for higher energy neutrons. We found that thermal neutron flux in Slanic is four times smaller than in Gran Sasso, probably due to lack of alpha-radioactive sources in the surrounding rocks. In contrast, the flux of higher energy neutrons in Slanic proved to be 1.4 times higher than in Gran Sasso, which can be explained by higher cosmic muon flux in Slanic.〈/p〉 〈p〉Our result for thermal neutron flux is lower than results of most of the previous measurements carried out in LNGS laboratory but thanks to a different method of analysis the reliability of our results is very high. The result for higher energy neutrons agrees with average energy spectrum resulting from previous measurements.〈/p〉 〈p〉Our measurements in Slanic were the first ones ever performed in this laboratory, and can be used as a reference by future experiments.〈/p〉 〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): Graeme Turkington, Kelum A.A. Gamage, James Graham〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Strontium-90 is one of the primary beta-emitting radionuclides found at nuclear decommissioning sites. Monitoring its activity in the environment is of utmost importance given its radiotoxicity. Current procedures for the beta detection of strontium-90 are time consuming, produce secondary waste and expensive. There is a demand for real-time in situ radiostrontium monitoring in groundwater at nuclear decommissioning sites. This paper presents a review of existing techniques for strontium-90 monitoring and examines a novel approach through direct beta detection with a gallium arsenide photodiode based detector. A proof of concept detector was modelled in the physics simulation software, Geant4, and evaluated as candidate for in situ detection of beta emitting radionuclides. The simulation results indicate that the detector is physically capable of counting 89.86% of incident 0.546 MeV electrons from a 1 mm range in water. This validation will provide the basis for further development of an in situ beta detector.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): A. Di Mauro, on behalf of the ALICE Collaboration〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉ALICE, the CERN LHC experiment devoted to the study of the QGP (Quark-Gluon Plasma) properties, will undergo a comprehensive upgrade during the second long shutdown of the LHC (in 2019-2020) to enhance the capability for high precision measurements of rare processes at low transverse momenta (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈msub〉〈mrow〉〈mi〉p〈/mi〉〈/mrow〉〈mrow〉〈mi〉T〈/mi〉〈/mrow〉〈/msub〉〈/math〉). One of the key elements of the upgrade strategy is the novel, high-resolution, ultra-light Inner Tracking System (ITS) consisting of seven concentric layers of Monolithic Active Pixel Sensors (MAPS) covering a total active area of 10 m〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si42.gif"〉〈msup〉〈mrow〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/math〉 segmented in 12.5 Gpixels. This paper presents an overview of the detector components, the most relevant characterisation results and the status of the detector construction.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): N. Karpushkin, D. Finogeev, M. Golubeva, F. Guber, A. Ivashkin, A. Izvestnyy, V. Ladygin, S. Morozov, A. Kugler, V. Mikhaylov, A. Senger〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) is aimed to explore the QCD phase diagram in the region of high baryon densities. The Projectile Spectator Detector (PSD) is the forward hadron calorimeter that will be used in the CBM to measure the event centrality as well as the reaction plane orientation in heavy-ion collisions in the beam energy range of 2–11 〈em〉A〈/em〉GeV with beam interaction rates up to 10 MHz. The supermodule consisting of 9 modules has been assembled to explore the performance of the PSD. Its response has been studied with proton beams in the momentum range 2–10 GeV/c at the CERN Proton Synchrotron (PS) T9 and T10 beam lines. For the first time, the energy resolution and the linearity of the response have been measured at such low energies. The PSD operation under radiation conditions at the CBM, as well as the results of one PSD module measurements with irradiated photodetectors are discussed.〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): Jan Grzegorz Hajnrych, Philippe Filliatre, Benoît Geslot〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A comparison between a few models of fission fragment penetration in several gases used in fission chambers is presented. To verify the energy loss of fission fragments, a comparison methodology was developed. It is based on comparative analysis of range experiments from third party publications with currently available models. We compared results from the SRIM code, the ICRU parametrization model implemented in Geant-4 and the LSS model. Albeit they are based on different hypotheses about the underlying physics that are not specific to fission fragments, those models reproduce fairly well the trend and order of magnitude of experimental data. Thanks to effective use of semi-empirical correlation fitted over large number of points, the SRIM code gives the closest results to experimental data: thus it is the model of choice for predicting and interpreting fission chambers’ signal.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): V. Cindro, S.H. Abidi, A.A. Affolder, M. Arratia, B. Ciungu, K. Dette, Z. Dolezal, C. Escobar, V. Fadeyev, C. García, I.M. Gregor, K. Hara, L.B.A. Hommels, Y. Ikegai, P. Kodys, G. Kramberger, J. Kroll, C. Lacasta, V. Latonova, D. Madaffari〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Miniature sensors with external dimensions of 10 mm x 10 mm were produced together with full-size sensors for the innermost ring (R0) of the end-cap part in the upgraded ATLAS inner tracker (ITk). AC- and DC-coupled n-type strips with three different pitches (wide, default and narrow) were processed on high-resistivity p-type FZ silicon substrates by Hamamatsu Photonics. The miniature sensors were irradiated with 70-MeV protons at CYRIC, Tohoku University (Japan) and reactor neutrons at the Jožef Stefan Institute (Slovenia) to three different 1-MeV neutron equivalent fluences: 0.5, 1 and 2 x 10〈sup〉15〈/sup〉〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈msub〉〈mrow〉〈mi〉n〈/mi〉〈/mrow〉〈mrow〉〈mi mathvariant="normal"〉eq〈/mi〉〈/mrow〉〈/msub〉〈/math〉cm〈sup〉−2〈/sup〉. The upper fluence range exceeds the highest anticipated in the innermost part of the ATLAS ITk-Strips over the HL-LHC lifetime (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si2.gif"〉〈mo〉∼〈/mo〉〈/math〉1.25 × 10〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈msup〉〈mrow〉〈/mrow〉〈mrow〉〈mn〉15〈/mn〉〈/mrow〉〈/msup〉〈/math〉n〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si39.gif"〉〈msub〉〈mrow〉〈/mrow〉〈mrow〉〈mi mathvariant="normal"〉eq〈/mi〉〈/mrow〉〈/msub〉〈/math〉cm〈sup〉2〈/sup〉). The charge collection in the test sensors was evaluated systematically using a 〈sup〉90〈/sup〉Sr 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si5.gif"〉〈mi〉β〈/mi〉〈/math〉-source and an Alibava analogue readout system at reverse-bias voltages up to 1000 V.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): P. Cardarelli, G. Paternò, G. Di Domenico, E. Consoli, M. Marziani, M. Andreotti, F. Evangelisti, S. Squerzanti, M. Gambaccini, S. Albergo, G. Cappello, A. Tricomi, M. Veltri, O. Adriani, R. Borgheresi, G. Graziani, G. Passaleva, A. Serban, O. Starodubtsev, A. Variola〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉ELI-NP-GBS is a high-brilliance gamma source that will produce monochromatic beams in the energy range 0.2-19.5 MeV through inverse Compton scattering. In order to obtain a monochromatic beam a collimation of the emission is necessary. Depending on the energy, the angular aperture required to provide the design bandwidth 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mi〉Δ〈/mi〉〈/math〉E/E=0.5% is between 70 and 700 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si2.gif"〉〈mi〉μ〈/mi〉〈/math〉rad. This collimation is provided by a stack of 14 tungsten slits, arranged with a relative rotation around the beam axis, so that the overlap will be a continuously adjustable aperture. To monitor the operation and alignment of the collimation, a set of detectors will provide a complete characterization of the gamma beam, including the measurement of the transverse spatial distribution. For this task a gamma beam profile imager based on a thin scintillator screen and a high-resolution CCD-camera was developed. In this work we briefly present the status of the collimation system and beam profile imager, which were designed, assembled and are currently under test at INFN-Ferrara laboratories.〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): N. Buzarbaruah, S.R. Mohanty, E. Hotta〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The adaption of new generation portable neutron sources has been increasingly marked in a wide range of research fields compared to the large-scale neutron generators. In this context, we have successfully demonstrated some essential parameters required for the emission of 2.45 MeV DD fusion neutrons from a steady state portable linear neutron source based on inertial electrostatic confinement scheme. The parameters that control the production of neutrons are the working pressure of the fuel gas, applied voltage, measured current and cathode geometries. The neutrons emitted from the source are confirmed using neutron monitor, bubble dosimeters, nuclear track detectors, and He-3 proportional counter. Presently, the device produces neutrons up to the order of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mo〉∼〈/mo〉〈/math〉 10〈sup〉6〈/sup〉 n/sec at discharge voltage ranging from -60 kV to -80 kV, and discharge current of 20 mA to 30 mA.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): Yu.A. Chesnokov, V.A. Maisheev〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The problem of creation of high energy neutrino beams on the basis of modern and future circular proton accelerators with the help of traditional technology seems to be expensive and difficult. Because of this, we propose the solution of this problem based on the usage of focusing bent single crystals. In the paper we demonstrate the possibilities of acceptance and focusing of a pion beam with the help of a crystal optical lens system. As an illustration of these features the calculated neutrino fluxes for energy of circulating proton beam equal to 6.5 TeV are presented.〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): L. Werner, M. Trunk, R. Gernhäuser, R. Gilles, B. Märkisch, Zs. Révay〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The cold neutron guide of the Prompt Gamma Activation Analysis (PGAA) instrument (Revay et al. 2015) at the Heinz Maier-Leibnitz Zentrum (MLZ) provides an excellent opportunity for neutron depth profiling (NDP) due to its high collimated neutron flux. We present the concept, layout and first measurements with the new N4DP facility set-up at this beamline. A special focus is put on background analysis and instrument characterization. We present measurements of a NIST reference sample and of boron-containing float glasses which are used for neutron optical waveguides. We give an outlook concerning the ongoing development of position-resolved NDP using silicon microstrip detectors.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): Z. Scholz, M. Millett, M. Schell〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Surrogate radiation sources are used to test detection equipment and train security personnel in the detection and interdiction of special nuclear material (SNM). Some current surrogate sources do not accurately match SNM energy spectra, including for HEU. In this research, we propose and investigate novel source configurations for higher fidelity surrogate SNM sources using thermal neutron capture reactions that result in prompt gammas. The objective is to create a surrogate source that has a more representative spectrum, low cost, and requires minimal security, special handling, and safety precautions.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 6 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): Ping Yang, Weiping Ren, Xiangming Sun, Guangming Huang, Le Xiao, Chaosong Gao, Xing Huang, Wei Zhou, Yashu Li, Jianchao Liu, Bihui You, Li Zhang, Jun Liu, Ying Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Circular Electron Positron Collider (CEPC) is proposed as a Higgs factory for precision measurement of properties of the Higgs boson. The CEPC vertex detector requires low material budget, high spatial resolution, fast readout and low power consumption. Monolithic Active Pixel Sensor (MAPS), as one of the promising candidate technologies, has been studied within the R&D activities for the CEPC vertex detector. This proceeding introduces recent development of a MAPS prototype using the TowerJazz 180 nm CMOS Image Sensor process. Two different binary front-end circuits have been designed to explore an in-pixel front-end structure suitable for a compact pixel in combination with an in-matrix sparsified readout circuitry. To achieve high granularity together with fast readout speed, a new architecture of asynchronous data-driven matrix readout has been implemented. The prototype contains 128 rows and 64 columns featuring a small pixel pitch of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mn〉25〈/mn〉〈mspace width="1em"〉〈/mspace〉〈mi mathvariant="normal"〉μ〈/mi〉〈mi mathvariant="normal"〉m〈/mi〉〈/math〉. The address of one hit pixel can be read out in 25 ns. This work presents the design of the prototype, which is currently under test.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): Seiichi Yamamoto, Hideo Nitta〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Gd〈sub〉3〈/sub〉(GaAl)〈sub〉5〈/sub〉O〈sub〉12〈/sub〉:Ce (GGAG) is a ceramic scintillator originally developed for X-ray CT, and it was also an excellent material for the development of an event-by-event-based radiation imaging detector when it was combined with a position sensitive photomultiplier (PSPMT). With the developed GGAG imaging detector, we found that the decay times for alpha particles and gamma photons were different. Also, we found that the decay times for alpha particles and beta particles were different. These characteristics are advantageous for developing an imaging detector for the simultaneous imaging of different types of radiation using pulse shape discrimination. Thus, we tested the separation of the images of the alpha particles and gamma photons using pulse shape discrimination. Also, we evaluated the separation of the alpha and beta particle images. In the pulse shape spectra, we could separate the peaks of Am-241 alpha particles and Cs-137 gamma photons with a peak-to-valley ratio (P/V) of 3.5. We obtained clearly separated images for Am-241 alpha particles and Cs-137 gamma photons using pulse shape discrimination. We could also separate the peaks of Am-241 alpha particles and Sr–Y-90 beta particles with a P/V of 1.5 in the pulse shape spectrum. We obtained separated images for Am-241 alpha particles and Sr–Y-90 beta particles using pulse shape discrimination. In addition, we could separate electrostatically collected natural alpha particles, Po-218 and Po-214, from the environmental beta particles and gamma photons using pulse shape discrimination. We conclude that the GGAG imaging detector is promising for simultaneous imaging and separating the images of different types of radiation using pulse shape discrimination.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 9 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): D. Bernard〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉No 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si64.gif"〉〈mi〉γ〈/mi〉〈/math〉-ray polarimeter sensitive above 1 MeV has ever flown space. 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si64.gif"〉〈mi〉γ〈/mi〉〈/math〉-ray polarimetry would be a new window on the radiative processes at work in cosmic sources, processes that produce linearly polarised emission, each of which with different polarisation fractions. The HARPO Collaboration has designed, built and characterised on beam a gas-TPC active target with which we have demonstrated for the first time the polarimetry of a linearly polarised MeV 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si64.gif"〉〈mi〉γ〈/mi〉〈/math〉-ray beam, from the analysis of the conversions to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si65.gif"〉〈msup〉〈mrow〉〈mi〉e〈/mi〉〈/mrow〉〈mrow〉〈mo〉+〈/mo〉〈/mrow〉〈/msup〉〈msup〉〈mrow〉〈mi〉e〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈/mrow〉〈/msup〉〈/math〉 pairs.〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): Songqing Tan, Rui Li, Chunlong Guo, Tao Shi, Yongqun Zhao, Xiaopeng Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper proposes a novel input power control strategy for high-power dynamic power supply for proton therapy. A buck chopper is staged in series between the input rectifier and the output chopper of the power supply to buffer the input power fluctuation, which can reduce the reactive power exchange between the power supply and power grid and reduce the power distribution requirements. The validity of this proposed control principle has been verified on a high-power dynamic dipole power supply for proton therapy.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): M. Mallamaci, B. Baibussinov, G. Busetto, D. Corti, A. De Angelis, F. Di Pierro, M. Doro, L. Lessio, M. Mariotti, R. Rando, E. Prandini, P. Vallania, C.F. Vigorito, for the CTA LST project〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A Silicon Photomultiplier (SiPM)-based photodetector is being built to demonstrate its feasibility for an alternative silicon-based camera design for the Large-Sized Telescope (LST) of the Cherenkov Telescope Array. It has been designed to match the size of the standard Photomultiplier Tube (PMT) cluster unit and to be compatible with mechanics, electronics and focal plane optics of the first LST camera. Here, we describe the overall SiPM cluster design along with the main differences with respect to the currently used PMT cluster unit. The fast electronics of the SiPM pixel and its layout are also presented. In order to derive the best working condition for the final unit, we measured the SiPM performances in terms of gain, photo-detection efficiency and cross-talk. One pixel, a unit of 14 SiPMs, has been built. We will discuss also some preliminary results regarding this device and we will highlight the future steps of this project.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 16 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): I. Mattei, G. Battistoni, M. De Simoni, Y. Dong, A. Embriaco, M. Fischetti, E. Gioscio, C. Mancini-Terracciano, M. Marafini, R. Mirabelli, S. Muraro, A. Sarti, A. Sciubba, E. Solfaroli Camillocci, G. Traini, S.M. Valle, V. Patera〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The use of C, He and O as beam particles in Particle Therapy (PT) treatments is getting more and more widespread as a consequence of the enhanced relative biological effectiveness and oxygen enhancement ratio of such projectiles with respect to protons. The advantages in the tumour control probability, related to the improved efficacy of ions, are calling for an online monitor of the dose release spatial distribution. Such technology is currently missing in PT treatments clinical routine. In this contribution the status of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mi〉Z〈/mi〉〈mo〉〉〈/mo〉〈mn〉1〈/mn〉〈/math〉 ions PT treatments monitoring, exploiting the detection of either charged secondary particles or neutrons, is reviewed. While charged fragments can be used to provide an online feedback to the beam control system, by correlating their emission profile with the position of the Bragg peak, neutrons have to be monitored to improve the experimental description of the secondary radiation component that significantly contributes to an undesired and not negligible dose deposition far away from the tumor region, enhancing the risk of secondary malignancies development after the treatment. Two tracker detectors, employing scintillating fibers, are presented: the Dose Profiler designed for charged secondary fragments measurements and the MONDO tracker dedicated to the characterisation of the secondary fast and ultrafast neutron component, within the MONDO (MOnitor for Neutron Dose in hadrOntherapy) project.〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): Huachang Liu, Jun Peng, Keyun Gong, Ahong Li, Bo Li, Qiang Chen, Xiaolei Wu, Mengxu Fan, Yun Wang, Peihua Qu, Shinian Fu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The China Spallation Neutron Source (CSNS) is an accelerator-based multidisciplinary user facility constructed in Dongguan, Guangdong, China. The injector of the CSNS accelerator consists of 4 conventional Alvarez DTL tanks, and it accelerates an H- beam from 3 MeV to 80 MeV. There is a series of accelerator physics and technology challenges in the DTL design and construction. The transverse focusing is arranged in a FFDD lattice utilizing a newly developed electromagnetic quadrupole magnets. The DTL cavity is copper-plated to enhance the electrical conductivity of the tank inner RF surface. There is not any space for steering magnet installing in the 36 m long DTL section, which leads to a rather high precision requirements for fabrication, installation and RF tuning. Benefited from the advanced fabrication technology and optimized tuning strategy, the CSNS DTL shows an excellent performance in the beam commissioning. The beam is successfully accelerated to 80 MeV with nearly 100% transmissions. The detailed physics and cavity design are described, construction and beam commissioning results are also shown.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): Y. Nagata, N. Kuroda, B. Kolbinger, M. Fleck, C. Malbrunot, V. Mäckel, C. Sauerzopf, M.C. Simon, M. Tajima, J. Zmeskal, H. Breuker, H. Higaki, Y. Kanai, Y. Matsuda, S. Ulmer, L. Venturelli, E. Widmann, Y. Yamazaki〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An antihydrogen detector consisting of a thin BGO disk and a surrounding plastic scintillator hodoscope has been developed. We have characterized the two-dimensional positions sensitivity of the thin BGO disk and energy deposition into the BGO was calibrated using cosmic rays by comparing experimental data with Monte-Carlo simulations. The particle tracks were defined by connecting BGO hit positions and hits on the surrounding hodoscope scintillator bars. The event rate was investigated as a function of the angles between the tracks and the energy deposition in the BGO for simulated antiproton events, and for measured and simulated cosmic ray events. Identification of the antihydrogen Monte Carlo events was performed using the energy deposited in the BGO and the particle tracks. The cosmic ray background was limited to 12 mHz with a detection efficiency of 81%. The signal-to-noise ratio was improved from 0.22 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉s〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉1〈/mn〉〈mo〉∕〈/mo〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/math〉 obtained with the detector in 2012 to 0.26 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉s〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉1〈/mn〉〈mo〉∕〈/mo〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/math〉 in this work.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 9 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): J. Zorn, for the CTA GCT project〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Compact High-Energy Camera (CHEC) is a design option proposed for the small-sized telescopes (SSTs) of the Cherenkov Telescope Array (CTA), focusing on the gamma-ray detection at the upper end of the gamma-ray spectrum (from 1 TeV up to around 300 TeV). Thanks to the use of dual-mirror, Schwarzschild-Couder (SC) optics, CHEC can be – by design – very compact (0.5 m 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mo〉×〈/mo〉〈/math〉 0.5 m), light (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si15.gif"〉〈mo〉∼〈/mo〉〈/math〉50 kg), and low-cost (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si15.gif"〉〈mo〉∼〈/mo〉〈/math〉150€). Using electronics based on TARGET (TeV Array Read-out with GSa/s sampling and Event Trigger) application-specific integrated circuits (ASICs) and field programmable gate arrays (FPGAs) allows a flexible trigger scheme and continuous sampling at 1 GSa/s. Full waveforms for all 2048 pixels are read out without loss at over 600 Hz. Two full prototype cameras have been developed. The first, based on multi-anode photomultipliers (MAPMs) as photosensors, was successfully characterised in the laboratory and during on-telescope campaigns where it saw Cherenkov light from air showers, as the first CTA camera prototype and the first camera ever using SC optics. The second, featuring upgraded ASICs and Silicon photomultipliers (SiPMs), is under commissioning at the Max-Planck-Institut für Kernphysik in Heidelberg.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): S. Abovyan, V. Danielyan, M. Fras, O. Kortner, H. Kroha, R. Richter, Y. Zhao, A. Baschirotto, M. De Matteis, F. Resta〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to fully exploit the physics potential of the ATLAS experiment at the HL-LHC, the trigger rate of and maximum latency of the first-level trigger system will be increased to 1 MHz and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mn〉10〈/mn〉〈mspace width="1em"〉〈/mspace〉〈mi mathvariant="normal"〉μ〈/mi〉〈mi mathvariant="normal"〉s〈/mi〉〈/math〉, respectively. In addition, a new first-level muon track trigger with high momentum resolution based on the ATLAS precision Muon Drift-Tube (MDT) chambers will be employed which requires triggerless readout. The TDC ASICs of the current front-end electronics of the MDT chambers are incompatible with these requirements. The front-end boards, each with a TDC chip and three 8-channel amplifier–shaper–discriminator (ASD) chips have to be replaced. Therefore, a new octal ASD2 ASIC has been developed in modern 130 nm IBM/Global Foundries CMOS technology. The chip also contains a Wilkinson ADC to perform both time-over-threshold and signal charge measurement. The ASD design has been fully qualified for the serial production of 80000 chips for ATLAS. The performance in terms of signal rise time and channel uniformity significantly surpasses the one of the previous chip while keeping the power consumption constant. In addition to the characterization with test pulses, several chips have been mounted on the front-end boards and tested in a muon beam at the Gamma Irradiation Facility GIF++ at CERN up to high counting rates where the superior drift time and spatial resolution becomes evident.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 913〈/p〉 〈p〉Author(s): J.P. Holzbauer, C. Contreras, Y. Pischalnikov, D. Sergatskov, W. Schappert〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉SRF cavity quality factors can be accurately measured using RF-power based techniques only when the cavity is very close to critically coupled. This limitation is from systematic errors driven by non-ideal RF components. When the cavity is not close to critically coupled, these systematic effects limit the accuracy of the measurements. The combination of the complex base-band envelopes of the cavity RF signals in combination with a trombone in the circuit allow the relative calibration of the RF signals to be extracted from the data and systematic effects to be characterized and suppressed. The improved calibration allows accurate measurements to be made over a much wider range of couplings. Demonstration of these techniques during testing of a single-spoke resonator with a coupling factor of near 7 will be presented, along with recommendations for application of these techniques.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): Mukhtar Ahmed Rana〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The influence of preservation period of CR-39 detectors, in refrigerator and in the laboratory atmosphere, on bulk etch rate is studied. The effect of etching solution usage time on the bulk etch rate is also investigated. Analyses and quantitative results in the said cases are presented. Finally, precision results on the use of CR-39 as a charged particle detector are presented in a systematic manner. These results are selected from our radiation detection and measurement experiments, ranged over last two decades. Selected results (unpublished and published) include CR-39 measurements of 5.9 MeV antiprotons, 6.12 MeV alpha particles and spontaneous fission fragments of 〈sup〉252〈/sup〉Cf. Our published results, presented here, are further analyzed and presented in comparison with new results and discussion. Experimental procedures of exposures, chemical etching, track measurements using the optical microscopy are described, keeping in view the new users and research students. Computer codes TRACK_Vision and SRIM were employed to provide a comparison with measurements of track parameters, where possible.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 8 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): H. Gómez〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Muon tomography, or muography, stands out as a non-invasive technique for the scanning of big objects internal structure. It relies on the measurement of the direction changes or absorption of atmospheric muons when crossing the studied object. For the first case, the trajectory reconstruction of muons upstream and downstream the object, provides information to generate its 3D density map. For bigger objects, a 2D map can be obtained by measuring the absorption for different incident directions. Proposed several decades ago, the performance achieved in particle detectors in the last years, specially in terms of stability, robustness and precision, has enlarged the possible applications of this technique.〈/p〉 〈p〉Bulk Micromegas represent a well-known technology suitable for the construction of muon telescopes based on these detectors. Thus autonomous and portable instruments have been conceived and constructed at 〈em〉Commissariat à l’Énergie Atomique et aux Énergies Alternatives〈/em〉 (CEA), being able to perform measurements 〈em〉in-situ〈/em〉, next to the studied objects. Furthermore, a Geant4-based simulation framework, capable to handle 3D models of the studied objects, is also being implemented to be used as support tool during the feasibility studies and for data analysis and results interpretation.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 12 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): B. Canion, J. Dreyer, O. Drury, D. Trombino, K. Nelson, B. Seilhan, S. Labov, K. Jarman, B. McDonald, M. Zalavadia, M. Myjak, D. Pfund, J. Forrester, G. Lawson〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉We investigate a new safeguards approach for verification of uranium processing operations via standoff measurement of UF〈sub〉6〈/sub〉 cylinder transports entering and leaving a facility. Current safeguards verification at facilities with UF〈sub〉6〈/sub〉 cylinders includes attended enrichment measurements of several randomly-selected cylinders using handheld instruments with inspection of all the cylinders typically only once a year. This approach requires significant inspector effort and can only be performed intermittently. Here we explore an unattended, multi-sensor enrichment measurement system that can operate continuously on cylinders in motion. Such an approach could be used to enhance continuity of knowledge by verifying that all shipments entering and leaving a facility are consistent with declared operations.〈/p〉 〈p〉The challenges in developing a standoff enrichment technique include limited statistical significance of the collected data, and interpreting the complex signatures from a shipment of UF〈sub〉6〈/sub〉 cylinders. These signatures vary with cylinder properties (e.g. the fuel cycle history, cylinder history, material distribution, material age, etc.) and measurement conditions (e.g. speed and distance of vehicle, detector response, cylinder orientation, attenuation from overpack and vehicle, etc.).〈/p〉 〈p〉In this paper, we demonstrate that we can extract useful enrichment signatures from standoff measurements of UF〈sub〉6〈/sub〉 cylinders entering and leaving a facility. Our initial analysis demonstrates a measurable difference in enrichment-related signatures from a cylinder in motion, measured with modest detection efficiency from several meters away. We also demonstrate that the inclusion of vehicle tracking increases the signal-to-noise ratio (SNR) of our radiation signatures, and decreases uncertainty of parameters needed for enrichment analysis, e.g. distance and velocity.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): G. Matarrese, P.A.P. Calò, F. Corsi, C. Marzocca, S. Petrignani〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉High-gain photomultiplier detectors are employed in an increasing number of applications in different fields to evaluate with great accuracy the occurrence time of light flashes composed by few or even single photons. Examples of these application fields are medical imaging, astroparticle and high energy physics, laser spectroscopy and LIDAR. To fulfill a good single photon timing accuracy, in the range of few hundreds of picoseconds, not only detectors with intrinsic excellent timing resolution (photomultiplier tubes, microchannel plated detectors, silicon photo multipliers, etc.) must be used, but the very first front-end amplifier (FEA) stage, used to read-out the detector, must also be carefully chosen and designed.〈/p〉 〈p〉We compare here three commonly used solutions for the FEA, from the point of view of the best achievable timing resolution: the charge sensitive amplifier (CSA), the voltage amplifier (VA) and the current buffer (CB). The results show that the CSA solution is limited in terms of frequency response by the usually large equivalent capacitance of the detector and that, surprisingly, the presence of the parasitic inductance 〈em〉L〈/em〉, due to interconnection detector-FEA, has a noise shaping effect which favourably affects the timing accuracy of the CB over the VA configuration. To support this study, simulations of simple implementations of the compared FEA solutions have been performed, under the same conditions.〈/p〉 〈p〉Moreover, with reference to a given detector and to a particular value of 〈em〉L〈/em〉, we show how the best timing accuracy of the CB is obtained by selecting an appropriate combination of input resistance and bandwidth of the FEA.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 5 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): I. Semeniouk, D. Bernard〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present the C++ implementation of an event generator for linearly-polarized gamma-ray conversions to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈mi〉γ〈/mi〉〈mo〉→〈/mo〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉e〈/mi〉〈/mrow〉〈mrow〉〈mo〉+〈/mo〉〈/mrow〉〈/msup〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉e〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈/mrow〉〈/msup〉〈/math〉 pairs. The generator uses the full 5D Bethe–Heitler probability density function for the generation of the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈mi〉γ〈/mi〉〈mo〉→〈/mo〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉e〈/mi〉〈/mrow〉〈mrow〉〈mo〉+〈/mo〉〈/mrow〉〈/msup〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉e〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈/mrow〉〈/msup〉〈/math〉 pair and for the recoil of the target nucleus. The same code is used for triplet generation. We present a verification of the model by comparing sample distributions with theoretical predictions.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): B. Juste, S. Morató, C. García, R. Miró, G. Verdú〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Different methods exist to verify bunkers design for radiation therapy medical facilities; analytical methods based on simplified equations and Monte Carlo methods. One of the main purposes of this work is to present the advantages of using Monte Carlo simulation to verify radiotherapy bunker shielding design. This methodology is more accurate and characterizes not only the fluence and dose three-dimensionally, but also the energy spectrum of particles generated by the LinAc. The other main purpose of the work is to analyze the importance of the generated photoneutrons when the LinAc emits high-energy photon beams (above 8 MeV), since numerous studies have found that these neutrons can expose the patient and clinical staff to non-negligible dose. The main novelty introduced by this work, is the creation of more realistic geometry simulation models to represent the radiotherapy facility by using CAD and meshes technologies which can be imported to MCNP6 Monte Carlo code. Results obtained using these bunker simulation models have been validated experimentally at the Hospital Universitari i Politècnic La Fe de Valencia facilities using two different neutron detectors; the neutron meter LB 6411 (designed between Berthold and Karlsruhe Research Center) and neutron detector model 42 - 41L (Ludlum, Prescila). Neutron dose results obtained with Monte Carlo and those measured experimentally fit correctly, validating this analysis methodology.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 9 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): L. Wiik-Fuchs, L. Diehl, R. Mori, M. Hauser, K. Jakobs, S. Kühn, U. Parzefall, A.A. Affolder, V. Fadeyev, C. García, C. Lacasta, D. Madaffari, U. Soldevila, Y. Unno〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The upgrade of the LHC to the High Luminosity LHC will challenge the silicon strip detector performance with high fluence and long operation time. Sensors have been designed and tests on charge collection and electrical performance have been carried out in order to evaluate their behaviour. Besides that, it is important to understand and predict the long-term evolution of the sensor properties. In this work, detailed studies on the annealing behaviour of ATLAS12 strip sensors designed by the ITK Strip Sensor Working Group and irradiated from 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈mn〉5〈/mn〉〈mo〉×〈/mo〉〈mn〉1〈/mn〉〈msup〉〈mrow〉〈mn〉0〈/mn〉〈/mrow〉〈mrow〉〈mn〉13〈/mn〉〈/mrow〉〈/msup〉〈msub〉〈mrow〉〈mi mathvariant="normal"〉n〈/mi〉〈/mrow〉〈mrow〉〈mi mathvariant="normal"〉eq〈/mi〉〈/mrow〉〈/msub〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉cm〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/math〉 to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si4.gif"〉〈mn〉2〈/mn〉〈mo〉×〈/mo〉〈mn〉1〈/mn〉〈msup〉〈mrow〉〈mn〉0〈/mn〉〈/mrow〉〈mrow〉〈mn〉15〈/mn〉〈/mrow〉〈/msup〉〈msub〉〈mrow〉〈mi mathvariant="normal"〉n〈/mi〉〈/mrow〉〈mrow〉〈mi mathvariant="normal"〉eq〈/mi〉〈/mrow〉〈/msub〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉cm〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/math〉 are presented. Systematic charge collection and leakage current measurements have been carried out during the annealing process until break-down or the appearance of charge multiplication. The annealing was carried out, separating the sensors into two groups being either annealed at 23 °C or 60 °C. Sensors showing charge multiplication have been then kept at high voltage for a long time in order to monitor their stability. The difference in the annealing behaviour between the two temperatures has been analysed and compared to similar measurements on n-type sensors and with a theoretical model. From the impedance measurements for the samples irradiated to low fluences it was possible to extract the effective doping concentration. This was compared to similar measurements on n-type sensors and with a theoretical model.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 9 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): Carlos Granja, Karel Kudela, Jan Jakubek, Pavel Krist, David Chvatil, Jan Stursa〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We evaluate and characterize the directional response of the semiconductor pixel detector Timepix to charged particles and secondary cosmic rays. The detector granularity and per-pixel spectrometric response enable to perform directional sensitive tracking of energetic charged particles in wide field-of-view. In the highly integrated MiniPIX readout the detector serves as a miniaturized, low-power and easily deployable particle micro-tracker. Angular measurements require normalization for the acceptance angle and geometric factor which are described and taken into account. The methodology and evaluation of directional response are developed for light charged particles and atmospheric secondary cosmic rays. Tests and calibration of angular resolution were performed with electron and proton beams. Resulting angular distributions are expressed in terms of elevation and azimuth angles in 14 bins and 36 bins, respectively, over the full 2〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mi〉π〈/mi〉〈/math〉 acceptance range. For zenith angle 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si17.gif"〉〈mi〉β〈/mi〉〈/math〉 〉 28° the angular distribution is fitted by 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈mo〉∼〈/mo〉〈/math〉 cos 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si4.gif"〉〈msup〉〈mrow〉〈/mrow〉〈mrow〉〈mi mathvariant="normal"〉n〈/mi〉〈/mrow〉〈/msup〉〈/math〉 (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si17.gif"〉〈mi〉β〈/mi〉〈/math〉) with n = 2.0 ± 0.2 expected from secondary cosmic ray muon distribution.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): G. Mauri, M. Mariotti, F. Casinini, F. Sacchetti, C. Petrillo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The application of Si sensors coupled to Gd converters as thermal neutron counters is assessed in a series of test experiments on the neutron beam, among which scattering from standard samples. The prototype 1d detector is a Si microstrip sensor directly coupled to natural Gd converter and equipped with standard front-end electronics. The raw scattering data, collected by interfacing the detector with the data acquisition system available at the neutron source, show advantages and limits of this technology when applied to neutron detection. To improve the performances of the Si-based detector by means of an optimized discrimination of the neutron signals from noise and background radiation, a pulse shape analysis method is proposed. The effectiveness of this method is then explored by experimental tests on the neutron beam of two more prototype detectors, namely a PIN diode coupled to   〈sup〉157〈/sup〉Gd〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si138.gif"〉〈msub〉〈mrow〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈/math〉O〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si139.gif"〉〈msub〉〈mrow〉〈/mrow〉〈mrow〉〈mn〉3〈/mn〉〈/mrow〉〈/msub〉〈/math〉 converters, and a Silicon photo-multiplier (SiPM) coupled to neutron scintillators. This study is aimed to real time applications and single event storage of the neutron information in time of flight instrumentation.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 31 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): D.M. Kasparek, B.S. McDonald, A.J. Gilbert, R.S. Wittman〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The International Atomic Energy Agency (IAEA) is responsible for verifying the mass of elemental uranium in various forms (powders, pellets, scrap) as part of inspections at nuclear fuel fabrication facilities. Current methods require in-field dissolution chemistry, which is time consuming and imposes operational challenges. Pacific Northwest National Laboratory (PNNL) is developing a prototype spectral x-ray radiography (SpecX) nondestructive assay system for noninvasive material mass quantification of uranium-bearing powders. The SpecX system uses a custom material estimation algorithm, which requires a high-fidelity pixel-by-pixel detector response model for accurate quantification. We performed a detailed characterization and built a model of a High-Energy X-ray Imaging Technology (HEXITEC) CdTe pixelated spectral detector. Here we present the detector characterization which led to that model, including a determination of the pixel-wise energy calibration, the detection efficiency, the detector uniformity, the detector stability, and a comparison of methods to remove charge-shared events.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 30 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): F. Pompili, B. Esposito, D. Marocco, S. Podda, M. Riva, S. Baccaro, A. Cemmi, I. Di Sarcina, L. Quintieri, D. Bocian, K. Drozdowicz, M. Curylo, J. Dankowski, J. Kotula, W. Maciocha, T. Nowak, J. Swierblewsk, L. Vermeeren, W. Leysen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Radial Neutron Camera (RNC) of ITER (International Thermonuclear Experimental Reactor) is a multichannel detection system designed to measure the uncollided neutron flux from the fusion plasma, providing information on the neutron emissivity profiles and source strength. Fission chambers and diamond detectors are candidate detectors for the RNC In-port subsystem. This is a high radiation environment (up to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mo〉∼〈/mo〉〈/math〉5 MGy gamma dose and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mo〉∼〈/mo〉〈/math〉〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈mn〉2〈/mn〉〈mo〉×〈/mo〉〈mn〉10〈/mn〉〈/math〉〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si4.gif"〉〈msup〉〈mrow〉〈/mrow〉〈mrow〉〈mn〉16〈/mn〉〈/mrow〉〈/msup〉〈/math〉 n/cm〈sup〉2〈/sup〉 neutron fluence) where about 500 baking cycles up to 240 °C are foreseen over the whole ITER lifetime. In order to assess the feasibility of using diamond detectors in such harsh conditions, and to study the best technological solutions, we are currently performing a set of tests to understand the behavior of diamond detectors under radiation and thermal stresses: (1) thermal stress tests at constant temperature of 240 °C and thermal cycling between 100 °C and 240 °C; (2) gamma-hardness test up to a total dose of 4.7 MGy; (3) neutron-hardness test (limited to 2 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si5.gif"〉〈mo〉×〈/mo〉〈mn〉10〈/mn〉〈/math〉〈sup〉14〈/sup〉 n/cm〈sup〉2〈/sup〉 in this work).〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Rahul Saha, Ramgopal V.S Uppaluri, Pankaj Tiwari〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Experimental investigations targeting optimum chemical slug formulations for tertiary enhance oil recovery of heavy crude oil in carbonate reservoir were carried out. Based on interfacial tension (IFT), emulsification, wettability alteration and core flooding studies, two alkalis and eight surfactants have been screened by considering conditions similar to oil reservoirs (0–20% salinity and 30–80 °C temperature). Dynamic IFT studies interestingly affirmed oil-layer break time phenomena and hence enhanced emulsification extent. Alkali, thermally stable surfactant mixture and alkali-surfactant mixture systems reduced IFT to 10〈sup〉−1〈/sup〉, 10〈sup〉−2〈/sup〉 and 10〈sup〉−3〈/sup〉 mN/m respectively. Flooding studied confirmed an additional oil recovery of 12.79% and 14.46% for alkali and alkali-surfactant mixture systems respectively. On the other hand, due to optimal emulsion stability, maximal residual oil recovery of 24.58% being achieved for a slug formulation of 0.1 wt% surfactant mixture. Surfactant concentration above 0.1 wt% enabled stronger emulsion formation that detriments displacement efficiency and oil recovery factor.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718311178-ga1.jpg" width="341" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Mi Zhang, Jilai Gong, Guangming Zeng, Peng Zhang, Biao Song, Weicheng Cao, Hongyu Liu, Shuangyan Huan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As a photocatalyst, bismuth vanadate coupled with reduced oxide graphene (BiVO〈sub〉4〈/sub〉-rGO) has been reported for dye degradation. However, this catalyst faced the disadvantages of low catalytic efficiency and long catalytic time. In this paper, BiVO〈sub〉4〈/sub〉-rGO composites were synthesized by a modified hydrothermal method, and characterization results showed the monoclinic BiVO〈sub〉4〈/sub〉 surface successfully coupled with a layer of rGO. The dye removal performance of BiVO〈sub〉4〈/sub〉-rGO composites were evaluated by the degradation of malachite green and rhodamine B under visible light irradiation and photocatalytic results showed that the BiVO〈sub〉4〈/sub〉 with rGO modification could effectively enhance the dyes removal performance. In a specific photocatalytic experiment, BiVO〈sub〉4〈/sub〉-rGO-300 could remove 99.5% MG in two hours and 99.84% RhB in four hours, which was superior to previous studies. Furthermore, application of catalyst in practical wastewater was also taken into account. MG and RhB were degraded by BiVO〈sub〉4〈/sub〉-rGO in several kinds of actual wastewater and experimental results showed that this catalyst could efficiently remove dye in actual environment. This improvement could be ascribed to the increase of special surface area, efficient charge transfer and reduction of electron-hole pair recombination with the incorporation of rGO. The influences of pH, supporting electrolyte and mechanism of the dye degradation were also investigated in details.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉The dyes removal performance for MG and RhB was effectively enhanced and the catalyst has a good potential in dye wastewater treatment.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571831135X-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Min Jae Shin, Young Jae Shin, Jae Sup Shin〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, the molecular imprinting technique and self-assembled monolayer technique were combined to increase the recognition ability of cholesterol. A self-assembled monolayer with 4-mercaptophenol and benzenethiol was formed on a gold plate, and the reaction of cholesteryl chloroformate with the phenol group in the 4-mercaptophenol was followed. This layer was then coated with poly(methyl methacrylate) (PMMA). In order to expose the cholesterol buried under the coating, the partial upper part of the coated PMMA was then removed by stroking the coated plate in acetone solvent. The molecular imprinted site was prepared by hydrolysis of the carbonate bond and extraction of the hydrolyzed cholesterol. This gold plate was used as a working electrode to test the recognition ability for cholesterol. The result showed that the plate obtained good recognition ability for cholesterol compared with cholic acid. The ratio of 4-mercaptophenol to benzenethiol was a very important factor in the ability to recognize cholesterol. Regulating the thickness of the coated PMMA was also one of the important factors to increase the ability to recognize cholesterol.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571831238X-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Nichaphat Thongsai, Nattapong Tanawannapong, Janjira Praneerad, Sumana Kladsomboon, Panichakorn Jaiyong, Peerasak Paoprasert〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rice husk, an agricultural waste that currently finds few uses, is rich in cellulose-based materials and silica. In this work, a simple one-pot method for preparing carbon dots and mesoporous silica from rice husk was developed, using hydrothermal and calcination methods. The carbon dots exhibited blue emission with excellent photostability, and had a diameter of 4–5 nm and a quantum yield of 3%. They were demonstrated to be capable of detecting alcohol vapors at room temperature, and of distinguishing between methanol, ethanol, and several volatile organic compounds when used as the sensing layer in an optical electronic nose system. The alcohol content of a commercial beverage was successfully determined using the carbon dot-integrated electronic nose. The solvation effect of the alcohol vapors on the electronic absorption spectra of model carbon dot structures was illustrated using time-dependent density functional theory with the dielectric polarizable continuum model. The UV–vis and computational results confirmed that the sensing mechanism of carbon dots is through the modulation of their optical absorbance governed by polar-polar interfacial interactions. This was experimental and computational demonstration of carbon dot sensing of vapors. Their excellent biocompatibility suggests biomedical applications, in addition to sensing. The production of two functional materials from a single low-value waste source was demonstrated.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718312378-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Chenhao Zhao, Zhibiao Hu, Jiangshui Luo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Porous carbon box or nanoplate has been prepared by synchronous carbonization/activation of potassium citrate, and the corresponding porous carbon nanoplate/Se composite can be obtained using a melting-diffusion method. The influence of structure parameters including specific surface area and porous structure of porous carbon and resultant carbon/Se composite on electrochemical properties are studied. It is found a moderate micropore size of carbon substrate and low specific surface area of carbon/Se composite are benefit to electrochemical performances. At an optimal temperature of 700 °C, the porous carbon composed of micro- and small meso-porous (2–4 nm) structure has a BET specific surface area of 695.4 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉, and the amorphous Se is uniformly encapsulated into its porous structure. As the cathode material of Li ion battery, the porous carbon nanoplate/Se composite delivers an initial discharge capacity of 589.2 mAh g〈sup〉−1〈/sup〉 with Coulombic efficiency of 72.6% at 0.2C, and capacity retention of 78.3% can be obtained after 500 cycles at 2C. Even at a high rate of 4C, a discharge capacity of 415.2 mAh g〈sup〉−1〈/sup〉 can be reached.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718312950-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Ting Zou, You Han, Xinxue Li, Wei Li, Jinli Zhang, Yan Fu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Controlled synthesis of noble metal nanocatalysts with desirable catalytic activities remains a great challenge. Inspired by electron-rich functional groups and supramolecular assembly properties of natural nucleotides, herein we propose a versatile approach to construct Pd nanocatalysts through employing seven nucleotides as both electron donors and stabilizers. The catalytic performance of nucleotide-Pd complexes are greatly associated with the chemical structures of nucleobases as well as the number of phosphate groups. Guanosine 5′-triphosphate-Pd complexes possess high activities in the hydrogenation reduction of 4-nitrophenol assisted by NaBH〈sub〉4〈/sub〉, with the relative rate constant of 7770 min〈sup〉−1〈/sup〉 mM〈sup〉−1〈/sup〉 at 25 °C. Pd(II)-coordinated nucleotides are also promising in NaBH〈sub〉4〈/sub〉-mediated degradation of organic dyes. This work demonstrates a green and facile process to construct Pd nanocatalysts containing abundant active sites under the assistance by natural nucleotides.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718314377-ga1.jpg" width="471" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Mirela Teodorescu, Maria Bercea, Simona Morariu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present study has been focused on investigation of some polymer mixtures of interest for biomedical applications. Three pairs of polymers, namely: poly(vinyl alcohol) (PVA)/poly(vinylpyrrolidone) (PVP), PVA/hydroxypropyl cellulose (HPC), Pluronic F127 (PL)/HPC were subjected to viscometic study in dilute solution. The intrinsic viscosity, the Huggins constant and 〈em〉B〈/em〉 parameter, as well as the miscibility parameters were discussed. The hydrodynamic properties of these polymer mixtures were analyzed as compared with the corresponding single polymer solutions at two reference temperatures, 〈em〉i.e.〈/em〉 the storage (25 °C) and physiological (37 °C) temperature. Each mixture has shown distinct behavior: PVA/PVP system is fully miscible regardless composition or temperature; the miscibility of PVA/HPC or PL/HPC mixtures is influenced in a specific manner by the ratio between the two polymers and by the temperature. The main interest is a better understanding of the polymer-polymer interactions and to identify the synergistic behavior in order to design multicomponent biomaterials with targeted properties. The compatibility of these polymers was attributed to the favorable hydrogen-bonding interactions between the hydroxyl groups of PVA and carbonyl groups of PVP, hydroxyl groups of PVA and HPC, and ether groups of PL and hydroxyl groups of HPC. On the other hand, hydrophobic interactions influence the polymer/polymer miscibility.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718311749-ga1.jpg" width="225" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Xiaopeng Xue, Zhonghao Xu, Israel Pedruzzi, Ping Li, Jianguo Yu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Interface phenomena between low molecular weight (LMW) carboxylic acids and muscovite was investigated through molecular dynamic simulation and experiment, where the typical monocarboxylic acids including formic acid (C〈sub〉1〈/sub〉), acetic acid (C〈sub〉2〈/sub〉), propionic acid (C〈sub〉3〈/sub〉) and butyric acid (C〈sub〉4〈/sub〉) were used as models. Density distribution, adsorption energy, root mean square dynamic (RMSD) of carboxylic acids on water-muscovite interface were calculated through molecular dynamic simulation, and the advanced characterization methods, such as ATR-FTIR spectra, AFM images and contact angle were performed to test and verify the relative simulation findings. The molecular simulation showed that carboxylic acids adsorbed on surface of muscovite through hydrogen bond between H atom of 〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉COOH functional group of carboxylic acid and O atom of muscovite, belong to outer sphere adsorption, and ATR-FTIR spectra and AFM images confirmed this finding. Adsorption energy for long carbon chain carboxylic acid (C〈sub〉4〈/sub〉) was higher than that for short carbon chain carboxylic acid (C〈sub〉1〈/sub〉, C〈sub〉2〈/sub〉 and C〈sub〉3〈/sub〉) due to the effect of carboxylic acid diffusion on water-muscovite interface. The hydrophilic functional group 〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉COOH of carboxylic acids preferably adsorbed on muscovite surface, while the hydrophobic functional groups 〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉CH〈sub〉3〈/sub〉 and 〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉CH〈sub〉2〈/sub〉 of carboxylic acids were far from the muscovite surface. So, the hydrophobicity on muscovite surface increased due to the adsorption of carboxylic acids, which resulted in the increase of contact angle of water on muscovite surface.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718310823-ga1.jpg" width="242" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Guowen Chen, Yuying Fu, Fuge Niu, Hao Zhang, Xiaomeng Li, Xin Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To evaluate the performance of biopolymer fabricated nanoparticle under commercial processing conditions, the stability of gum Arabic (GA)-zein-cur (curcumin) colloidal system was recorded and analyzed. The results showed that GA-zein-cur system is colloidal stable in the pH range of 5–8, however, encapsulated curcumin degraded rapidly as long as the pH changes. As for processing temperature, more than 70 °C will affect the spatial structure of zein and leading to the leak or exposure of encapsulated curcumin which result in the degradation of curcumin. Na〈sup〉+〈/sup〉 has no significant effect on colloidal and chemical performance of nanoparticles while Fe〈sup〉3+〈/sup〉 could penetrate the zein nanosphere and compromise curcumin. Results of our work imply that the protein-based core-shell delivery system has advantages in solubilizing the hydrophobic compounds and has certain ability to protect the encapsulated material against the unfavorable environment.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718308707-ga1.jpg" width="313" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Haiqin Wu, Liang Yan, Liyang Fu, Lan Jin〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The interaction of alizarin with aminophenylboronic acid (ARS-PBA) was used through a new strategy for electrochemical sensors of glucose. In the present work, ARS-PBA complex and the layered double hydroxide nanosheets (LDH nanosheets) were successfully assembled on indium tin oxide (ITO) electrodes via layer by layer technology method. The resulted electrode was characterized by UV–vis, X-ray diffraction (XRD), atomic force microscope (AFM) and scanning electron microscope (SEM) to achieve the morphological, structural and compositional information. Cyclic voltammetry and differential pulse voltammetry were conducted to investigate electrochemical properties of the modified electrode. Moreover, the modified electrode was used as a non-enzymatic sensor for glucose determination, exhibiting good electrochemical properties, fast response time and long-term stability. At the optimum conditions, the constructed electrode sensor shows a linear range of 0∼1.00 μmol/L and a low detection limit of 4.0 nmol/L (S/N = 3) for glucose. On the basis of affinity between glucose and ARS-PBA complex, the functionalized electrode showed a high selectivity toward glucose over other concomitant biomolecues (dopamine, uric acid and ascorbic acid). Therefore, a simple and effective electrochemical method was developed and offers a complementary tool for the detection of glucose.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718313219-ga1.jpg" width="358" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Priyadharsan A., Shanavas S., Vasanthakumar V., Balamuralikrishnan B., Anbarasan P.M.〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The sunlight driven photocatalytic activity of semiconductor based nanocomposites has attracted extensive attention in recent years for environmental remediation and energy applications. Here, we report an effective strategy to synthesis ternary MoS〈sub〉2〈/sub〉-ZnO-reduced graphene oxide (MZG) nanocomposite as a photocatalyst by a facile hydrothermal method. The prepared nanoparticles were characterized by various analytical tools. The basic photocatalytic mechanism of the composite material was exhibited the photoexcited electrons of ZnO can be readily transported to MoS〈sub〉2〈/sub〉 through rGO backbone, reducing the electron-hole pair recombination. The photocatalytic performance was optimized using methylene blue as a model organic dye under natural sunlight irradiation. The results were compared with pure and binary, MZG ternary nanocomposites exhibit superior photocatalytic activity. In a continuation of environmental remediation studies, MZG ternary nanocomposites revealed high antibacterial activity towards 〈em〉Escherichia coli (E.coli)〈/em〉 and 〈em〉Staphylococcus aureus (S.aureus)〈/em〉, highlighting its potential photocatalytic and antibacterial properties at different industrial and medical applications. This study may afford some inspiration for the rational design and facile synthesis of composite catalysts with a high and tunable catalytic property through a green, efficient pathway.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718310835-ga1.jpg" width="233" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Anusha Chandra, Bhuvanesh E, Sujay Chattopadhyay〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Permselectivity and water uptake behaviors of anion exchange membrane (AEM) were investigated with organic acids. Contribution of the number of carboxyl group (acetic acid: AA, malic acid: MA, citric acid: CA) and hydrocarbon chain lengths (formic acid: FA, AA, propionic acid: PA and n-butyric acid: BA) in water uptake and permselectivity values were separately investigated with five different concentrations 0.025, 0.05, 0.075, 0.1 and 0.125 mol·L〈sup〉−1〈/sup〉 of each acid at two different pH 2.0 and 7.5 conditions. Microstructural changes occurring due to interaction of carboxylate anion and NR〈sub〉4〈/sub〉〈sup〉+〈/sup〉 groups of AEM resulted in permselectivity behavior. Permselectivity trend: CA 〈 MA 〈 AA could be explained by counter-ion condensation resulting out of strong counter-ion interactions with AEM fixed charges. Co-ion mobility values could explain variation in permselectivity at pH 2.0 and 7.5. While, water uptake and ionic size were dominant factors to explain the permselectivity trend: FA 〉 AA 〉 PA 〉 BA. Complex nature of interactions due to properties (size, charge, ionic charge density, mobility, diffusivity, stokes radius etc.) of carboxylate anions were explained using diffusivity ratio (counter/co-ion, 〈em〉D〈sub〉2〈/sub〉/D〈sub〉1〈/sub〉〈/em〉), adsorption equilibrium and fraction of dissociated species.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718313906-ga1.jpg" width="276" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Svetlana Fedorenko, Alexey Stepanov, Rustem Zairov, Ondrej Kaman, Rustem Amirov, Irek Nizameev, Kirill Kholin, Ildus Ismaev, Alexandra Voloshina, Anastasiya Sapunova, Marsil Kadirov, Asiya Mustafina〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present work introduces one-pot synthetic route to join ultra-small iron oxides (6 nm) with Gd(III) complexes in small (∼30 nm) silica nanoparticles with high longitudinal and transverse relaxivity values (r〈sub〉1〈/sub〉 = 34.7 mM〈sup〉−1〈/sup〉 s〈sup〉−1〈/sup〉 and r〈sub〉2〈/sub〉 = 64.7 mM〈sup〉−1〈/sup〉 s〈sup〉−1〈/sup〉 at 0.47 T). The design of the nanoparticles is based on the core-shell morphology, where the Gd(III) complexes were doped into the exterior silica layer. The doping mode is the reason for an efficient interfacial hydration and the small suppressing of r〈sub〉1〈/sub〉 by iron oxides. The measurements on the whole body scanner at 1.5 T confirm the high contrasting abilities of T〈sub〉1〈/sub〉 (Gd) and T〈sub〉2〈/sub〉 (iron oxide) components in the nanoparticles. Poor aggregation behavior of the nanoparticles in water is due to high electrokinetic potential value (−78 mV). Greater aggregation of the nanoparticles in the buffer solutions of bovine serum albumin enhances the disturbing effect of iron oxides on the longitudinal relaxation and facilitates the transverse relaxation. The higher surface activity of the nanoparticles results in their greater cytotoxicity versus the silica coated iron oxides, although the cytotoxicity is low in the concentration range which is within the region of interest for MRI technique.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718311166-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Jiwei Lu, Mingjun Sun, Zhitao Yuan, Shengliang Qi, Zhongyun Tong, Lixia Li, Qingyou Meng〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Serpentine, as a common magnesium silicate mineral found in many ores around the world, is usually dispersed/depressed with the dispersants/depressants by adsorbing on the surface of serpentine. Therefore, in this work, the interaction mechanism of the dispersant of sodium hexametaphosphate (SHMP) was investigated in detail though solution chemistry calculations, Fourier transform infrared spectroscopy (FTIR) analyses, zeta potential measurements, adsorption and ion release tests, and molecular dynamics (MD) simulations. Results indicated that anionic components of H〈sub〉2〈/sub〉PO〈sup〉−〈/sup〉〈sub〉4〈/sub〉 and HPO〈sup〉2−〈/sup〉〈sub〉4〈/sub〉 in SHMP, as the predominant and effective species, adsorbed on the Mg and Si sites of the serpentine surfaces, which occurred on the Si site through the electrostatic interaction and on the Mg site through the chemical adsorption. As a result, the surface charge of serpentine was reversed from positive to negative at all pH region examined. In addition, ion release tests confirmed that SHMP dissolved some Mg ions for forming soluble complexes from the serpentine surface into the solution. Thus, the negative charge of it was further enhanced, which would lead to much stronger repulsion between negatively charge valuable minerals (e.g., pentlandite) and serpentine. Thus, the serpentine would be well dispersed with the valuable minerals.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718312329-ga1.jpg" width="398" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Konstantin Popov, Maxim Oshchepkov, Elena Afanas’eva, Elena Koltinova, Yulia Dikareva, Hannu Rönkkömäki〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Scaling in reverse osmosis facilities, boilers, heat exchangers, evaporation plants, and oilfield applications is a serious problem worldwide. A widely used solution for controlling scale deposition is an application of chemical inhibitors. However, irrespective of the broad and a long-term antiscalant application, the mechanisms of scale inhibition are still the matter of discussions.〈/p〉 〈p〉In order to provide a new insight into the mechanism of the scale inhibition, a novel dynamic light scattering (DLS) special technique is used to study the bulk supersaturated gypsum aqueous solutions during the induction period. It is based on the standard Ag nanoparticles (ARGOVIT) injection into the supersaturated gypsum solution. These nanoparticles act as an internal indifferent light scattering intensity reference, and provide a semiquantitative measurement of a relative gypsum particles content in a blank solution and in the system treated with phosphonates: amino-tris(methylenephosphonic acid), ATMP; 1-hydroxyethane-1,1-bis(phosphonic acid), HEDP; 2-phosphonobutane-1,2,4-tricarboxylic acid, PBTC. It is found that ATMP sufficiently reduces the number of gypsum nuclei, spontaneously formed in the supersaturated solutions. The less effective inhibitors of gypsum scaling HEDP and PBTC also reduce the gypsum nuclei number, but to a less extent. A tentative nonconventional mechanism of scale inhibition in the bulk supersaturated aqueous solutions of gypsum is proposed.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718307192-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Hong-Liu Jiang, Jie-Ci Lin, Wei Hai, Hong-Wei Tan, Yu-Wei Luo, Xiao-Lin Xie, Yao Cao, Fu-An He〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, a novel crosslinked porous β-cyclodextrin-based polymer containing carboxylic acid groups (CT-β-CD) was synthesized successfully and characterized by SEM, FTIR, 〈sup〉13〈/sup〉C solid-state NMR, water-contact-angle measurement, and TGA. The resultant CT-β-CD with triple absorption effects including inclusion complextion, porous network capture, and electrostatic interaction was employed as an adsorbent for removing methylene blue dye from aqueous solution, which exhibited several advantages such as high absorption capacity (q〈sub〉max〈/sub〉 = 672 mg/g), rapid absorption rate, good recyclable ability, and selective adsorption for cationic dyes. The influences of initial MB concentration, absorption time, and pH value on the absorption behavior of CT-β-CD for MB were also investigated. In addition, it was found that the pseudo-second-order kinetic and the Langmuir model for adsorption isotherm could be used to describe the MB absorption behavior of CT-β-CD.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718313050-ga1.jpg" width="437" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Qing Fan, Dali Zhou, Lei Yang, Jiabei Zhou, Shuang Yang, Yongqiang Yang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Glass lubricants have great potential in industrial metal forming processes such as hot extrusion of titanium and titanium alloys. In this work, based on the extrusion process of commercial-purity titanium (TA2) at 800 °C, glass lubricants with low melting points are designed. The thermal properties, high-temperature oxidation resistance and friction properties of uncoated and glass-coated TA2 samples are systemically studied, which reveals the good lubricating and anti-oxidation properties of the samples. The glass lubricant melts into a viscoelastic film at 800 °C to insulate TA2 from oxygen and reduce friction, and automatically peel off during cooling due to the significantly mismatched thermal expansion between the glass coating and TA2 substrate. This work provides a guidance for designing glass-based lubricants used in hot extrusion of metals.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571831152X-ga1.jpg" width="322" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): T. Rijnaarts, J. Moreno, M. Saakes, W.M. de Vos, K. Nijmeijer〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Reverse electrodialysis (RED) is a process to harvest renewable energy from salinity gradients. Under lab conditions with artificial salt solutions, promising results have been achieved in recent years. However, in large scale industrial applications, natural waters are used and that poses challenges such as fouling. Fouling of anion exchange membranes (AEMs) by organic matter (e.g. humic acids) has been identified as a possible cause that lowers RED performance with natural waters. In this work, natural river and seawater at the Afsluitdijk (The Netherlands) are used to study the RED performance of six different AEMs. These AEMs are characterized before and after RED experiments with natural waters. The effect of natural fouling is found to be specific for each AEM and highly dependent on their respective chemistries and associated membrane properties. Firstly, aromatic AEMs with a low swelling degree showed a permselectivity decrease as well as membrane resistance increase. Secondly, aliphatic AEMs with a medium swelling degree experienced only a membrane resistance increase. Finally, only a decrease in permselectivity was observed for aliphatic AEMs with large swelling degrees. Subsequently, the effect of AEM fouling is compared to the observed decrease in RED performance and this shows that AEM fouling can only explain a minor part of the losses in open circuit voltage (OCV). The RED power densities dropped by 15–20% over 12 days, independent of the AEMs selected, while the reduced AEM performance could only explain 2–4% of this reduction in power density. This demonstrates that next to AEM fouling, also other factors, such as spacer fouling, are expected to be the dominant fouling mechanism, reducing the performance to a much larger extent.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718313505-ga1.jpg" width="481" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Yibo Ouyang, Jin Zhao, Ri Qiu, Shugang Hu, Yan Zhang, Peng Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bioinspired superhydrophobic and oil-infused surfaces have been recognized as interesting and promising materials for a wide range of applications correlated with water environment, such as corrosion and biofouling inhibition. Which material is the better choice still waits to reveal. In this study, taking stainless steel as the substrate, superhydrophobic and oil-infused surface based on Cu(OH)〈sub〉2〈/sub〉 matrix with prickly chestnut husk morphology is respectively obtained via successive steps. During the preparation of superhydrophobic surface, firstly, discrete Cu particles are electrodeposited onto stainless steel. After that, oxidation of the as-deposited Cu particles leads to the prickly Cu(OH)〈sub〉2〈/sub〉 following a dissolution-crystallization mechanism. Under a mild condition, dodecanethiol vapor modifies prickly matrix to achieve superhydrophobicity by anchoring the long-chain organic moiety onto Cu(OH)〈sub〉2〈/sub〉 surface. Since superhydrophobic matrix is intrinsically superoleophilic, oil-infused surface is finally constructed onto stainless steel. Taking typical marine fouling organisms including sulfate-reducing bacteria (SRB) and diatoms as the representatives, oil-infused surface can steadily prevent the biofouling on stainless steel, showing the better performance than superhydrophobic surface for biofouling inhibition. Using epoxy resin as the artificial fouling agent, the pulling force to remove the glued solid on oil infused surface is much lower than that on bare stainless steel, illustrating oil layer acting as the separation cushion between fouling agent and underneath substrate.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Superhydrophobic and oil-infused surface based on prickly chestnut husk morphology Cu(OH)〈sub〉2〈/sub〉 are used as the representatives to illustrate which is the better choice to prevent marine biofouling.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718307477-ga1.jpg" width="295" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Chengyi Wang, Lin Chen, Shanshan Liu, Liang Zhu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, nitrite desorption from activated carbon fiber (ACF) in capacitive deionization (CDI) and membrane capacitive deionization (MCDI) was examined and the effects of the operation parameters (pH, voltage, temperature and flow rate) and co-existing matters were deeply investigated. Desorption mechanisms were analyzed via Brunauer–Emmett–Teller (BET) and Fourier transform infrared spectroscopy (FTIR). Results showed that the final desorption ratio increased from 0 to 100% in MCDI and the enhancement was also observed in CDI that the ratio increased from 18.7 to 83.5% when solution pH increased from 2 to 10. Increasing the voltage and solution temperature also contributed to the ion desorption both in CDI and MCDI, while the effect of flow rate was negligible. Generally, MCDI showed greater desorption performance than CDI due to the elimination of co-ions effect. However, it was interesting to find that when the voltage was in the range of 0.4-0.6 V, the desorption ratio increased from 38.4% to 50.8% in MCDI which was lower than that in CDI (45.4% to 55.8%). One possible explanation was that the presence of membranes would inevitably introduce additional resistance into the system and decrease effective voltage especially at lower voltage. Compared to the desorption performance in MCDI when the solution pH was 2, the greater desorption performance was observed in CDI which was mainly attributed to the site competition. As for the influence of coexisting matters, the presence of bovine serum albumin (BSA) posed an adverse effect for the ion desorption both in CDI and MCDI. The inhibition effect was more serious in CDI, and pore blockage caused by BSA attachment onto ACF was the main mechanism. Therefore, this study would provide some referential advice for the investigation of ion desorption in CDI and MCDI.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718312275-ga1.jpg" width="255" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 28 June 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Anwesha Sarkar, Brent S. Murray〈/p〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Anh-Tu Ngo, Salvatore Costanzo, Pierre-Antoine Albouy, Vincent Russier, Sawako Nakamae, Johannes Richardi, Isabelle Lisiecki〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Novel colloidal crystals made of maghemite nanocrystals are fabricated by a co-evaporation method with a mixture of ethanol/hexane. Through a series of comprehensive characterization performed by grazing incidence small-angle X-ray scattering (GISAXS) and field emission gun scanning electron microscope (FEG-SEM), we show the first example of well-defined face-centered cubic (fcc) colloidal crystals. In order to obtain a clear picture of the crystal formation, the amount of ethanol in the solution is monitored using gas chromatography. In parallel, the interactions between the nanocrystals are calculated by statistical mechanics theory using solubility parameters. Theory predicts the formation of colloidal crystals at quite high amounts of ethanol around 15%, in perfect agreement with experimental results. We show that the theory can further be applied to predict the optimal experimental conditions for the formation of colloidal crystals using other solvent mixtures.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571830788X-ga1.jpg" width="446" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Xiaoyu Gao, Gang Wen, Zhiguang Guo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Based on controlling ZnO nanoarrays morphology and employing fluorine-free modification agent, superhydrophobicity in air and superoleophobicity under water were successfully achieved on the prepared cotton fabric surfaces via a two-step hydrothermal reaction. To increase adhesion between ZnO crystal layer and substrate surface, two kinds of silane coupling agents (hydrophobic TTOP-12 and hydrophilic KH550) were added selectively in the pretreatment process. The as-prepared fabric exhibited great tolerance and durableness towards external harsh environments, such as mechanical abrasion, UV radiation, immersion of acid or alkali, and high temperature. In comparison, superhydrophobic fabrics showed superior separation effect for heavy oil and water mixture, while underwater superoleophobic fabric can also show efficient separation of water and light oil with high separation efficiency and flux. In a word, heavy/light oil and water mixtures can be separated efficiently as need by choosing cotton fabrics with various wettabilities.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉The cotton fabrics with superhydrophobic and superolephobic underwater were fabricated in this paper via controlling ZnO crystal morphology and choosing various modification agents, and the results showed that they possessed efficient separations as need for oil/ water mixtures with both an efficiency and a high flux.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718311129-ga1.jpg" width="386" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Zane A. Grady, Alexandria Z. Arthur, Christopher J. Wohl〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Controllable surface morphology is requisite across a gamut of processes, industries, and applications. The surface morphology of silica-coated polystyrene microspheres was controllably modified to enable generation of both smooth and bumpy, or raspberry-like, surfaces. Although smooth and raspberry-like silica shells on polystyrene templates have been demonstrated extensively, the method described here used readily available materials to produce radical changes in surface morphology from a single polystyrene template coated in silica through a facile sol-gel reaction processes. Silica shells were deposited via a sol-gel process (using tetraethyl orthosilicate as the silica precursor) onto 1 to 2 μm diameter anionic polystyrene spheres, fabricated by emulsifier-free polymerization. By varying the concentration of silica precursor and ammonium hydroxide catalyst and altering the electrostatic surface interactions via addition of a cationic polymeric brush, an array of surface topologies was generated. Incremented addition of the ammonium hydroxide base catalyst and sol-gel precursors generated smooth silica shells, whereas identical one-pot reactions led to raspberry-like shells. This modification of sol-gel deposition on large polystyrene cores via means of reactant addition offers additional control over sol-gel shell morphologies.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718313414-ga1.jpg" width="264" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Mahsa Baghban Salehi, Mina Soleimanian, Asefe Mousavi Moghadam〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, the overall performance of a disproportionate permeability reduction mechanism for a sulfonated polyacrylamide copolymer and the chromium triacetate crosslinker was investigated. A home-built gel filtration system was used for visual inspections and evaluations of the hydrogel performance. The experiments were conducted based on rheological test plans, energy-dispersive X-ray spectroscopy, and scanning electron microscope. Accordingly, quadratic equations based on the polymer and crosslinker concentrations were presented predicting the rupture pressure gradient of the hydrogel and the hydrogel output due to the oil and water injection through the hydrogel. It was indicated that the polymer concentration was the main effect on the rupture pressure gradient of the hydrogel and hydrogel output. Moreover, under constant concentration of crosslinker, increasing polymer concentration showed an increase in rupture pressure gradient and output of the hydrogel due to the increase of elastic modulus of hydrogel network and its strength as a viscoelastic material. As the hydrogel structure illustrated no rupture during the gel filtration experiments, a mechanism presented justifying the disproportionate permeability reduction phenomenon which in that under constant condition, the oil permeability through hydrogel was greater than the water permeability.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718312561-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Tanara Sartori, Gabriela Feltre, Paulo Jose do Amaral Sobral, Rosiane Lopes da Cunha, Florencia Cecilia Menegalli〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This work aimed at evaluating the influence of glycerol concentration and storage relative humidity (RH) on gluten-based adhesive properties. Adhesive aging and adhesive application over different food substrates were also evaluated. For such purpose, three adhesive formulations were developed from different gluten:glycerol ratios (1:0.6, 1:1, and 1:1.4), which were applied over a pectin-based film as support material. The adhesives presented better adhesion and cohesion properties when stored at 58% RH. The formulation with the best adhesive properties was the 1:1 gluten:glycerol ratio. The degradation of the adhesives during aging was considered small in the first thirty days. The adhesives presented potential to be applied on food grade materials with low hydrophilicity.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718312032-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Xuemei Zheng, Shiyu Fu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nanocellulose, a nano blocks extracted from plant biomass, is a potential candidate for fabricating superhydrophobic materials by reconstructing roughness surface and modifying with low-surface-energy chemicals. In this work, a facile spray drying was used to prepare the nanocellulose-based micro-particles with hierarchical surface structure. The surface structure of particles can be regulated by changing the size of nanocellulose. The prepared particles were modified with methyltrimethoxysilane (MTMS) by chemical vapor deposition (CVD), and then the modified particles mixed with polydimethylsiloxane (PDMS) proportionally are formulated a new coating, which can be sprayed on filter papers or glass to obtain superhydrophobic surface. The new finding is that the length of nanofiber had great influence on surface structure of formed particles from spray, and the shorter nano-fiber was easier to derive micro-particles with more compact, more even rough surface structure and better superhydrophobicity of final coated materials compared with the longer nanofiber. The superhydrophobic property of the coating can be controlled simply by changing the cellulose nano-fiber length, which is of great significance on hierarchical structure design of the nanocellulose-based superhydrophobic materials.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718307751-ga1.jpg" width="302" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Erica Pensini, Abdallah Elsayed, Braulio Macias Rodriguez, Alejandro G. Marangoni, Ashutosh Singh, Brent Sleep, Gordon Hayward, Kristine Lamont, Christopher M. Collier〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Trapping and treating Cr(VI) is of great importance to environmental applications. In this work, the natural polymer scleroglucan and the reducing agent sodium thiosulfate were used to produce a water-based polymeric fluid to simultaneously trap and treat Cr(VI) in the subsurface. The thiosulfate reduced toxic Cr(VI) to less toxic Cr(III), as was apparent from fluid discoloration from bright orange to dark brown. Additionally, the viscosity of scleroglucan fluids containing sodium thiosulfate was low before mixing with Cr(VI) (150 mPa·s with 1 wt% scleroglucan in water at 23 °C), suggesting that the fluids can be effectively pumped in the subsurface. As sorption of scleroglucan onto geological substrates can affect its transport in geological media, sorption was measured using a Quartz-Crystal Microbalance with Dissipation Monitoring (QCM-D). Sorption of scleroglucan onto silica (used as a model geological substrate) was promoted in 100 mM CaCl〈sub〉2〈/sub〉 at pH = 7 and in deionised water at pH = 4, whereas it was hindered by humic acids (HA), which are usually naturally present in groundwater. Upon contact with Cr(VI) and sodium thiosulfate, scleroglucan chains crosslinked and the fluids gelled, acquiring high viscosity (approximately 2000 mPa·s) in water, in salt solutions (100 mM KCl or 100 mM CaCl〈sub〉2〈/sub〉) and in the presence of HA. Gelled scleroglucan was also characterized by high shear viscoelastic moduli and became plastic at high compressional loads (70 N to 100 N, depending on the water chemistry). Gelation is due to the crosslinking of scleroglucan by Cr(III), following the reduction of Cr(VI) by sodium thiosulfate. Scleroglucan fluids containing sodium thiosulfate may potentially form a barrier around the Cr(VI) contaminated zone, preventing its migration during treatment.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718311373-ga1.jpg" width="309" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Patricio Serafini, Marcos Fernández Leyes, Jhon F. Sánchez M., Romina B. Pereyra, Erica P. Schulz, Guillermo A. Durand, Pablo C. Schulz, Hernán A. Ritacco〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The micellization process of the aqueous mixed system triton X-100 (TX100) – dodecyltrimethylammonium bromide (DTAB) has been studied with a battery of techniques: surface tension, static and dynamic light scattering and ion-selective electrodes. Results have been also analysed with two thermodynamic procedures: the Regular Solution Theory or Rubingh’s model and the recently developed Equation Oriented Mixed Micellization Model (EOMMM). For α〈sub〉DTAB〈/sub〉 ≤ 0.40 (α〈sub〉DTAB〈/sub〉: total molar fraction of the system without considering the water), the micelles are predominantly TX100 with scarce solubilized DTA〈sup〉+〈/sup〉 ions, with TX100 acting as a nearly ideal solvent. In the range 0.50 ≤ α〈sub〉DTAB〈/sub〉 ≤ 0.75, it seems that none of the components acts as a solvent. Above α〈sub〉DTAB〈/sub〉 ≈ 0.75 there are noticeable changes in the size and electrophoretic mobility of the micelles. These phenomena have been interpreted in the light of the thermodynamic results and literature on some TX100-ionic surfactant mixtures. The case under study is an almost ideal but very asymmetric mixed surfactants system, what is very interesting in view of the very different nature and structures of the components.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718310574-ga1.jpg" width="235" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 27 May 2017〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Johanna Milsmann, Kathleen Oehlke, Katrin Schrader, Ralf Greiner, Anja Steffen-Heins〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Edible solid lipid nanoparticles (SLN) stabilized by a mixture of food grade emulsifiers (soy bean lecithin, Tween 20, sucrose stearate) were added to o/w emulsions previously stabilized by anionic SDS, non-ionic Tween 20 or cationic CTAB. The aim of the study was to understand the fate of both SLN and oil droplets in these mixtures focusing on the impact of the surfactant used to stabilize the emulsion. The presence of SLN in emulsions led to increased emulsion stability as reflected by droplet size measurements and accelerated creaming experiments. This could be attributed to an increase in the viscosity of the sample, but also to changed properties of the o/w interface. Zeta potential measurements revealed that the surfactant composition at the o/w interface had changed in SDS and CTAB stabilized but not in Tween 20 stabilized emulsions. SLN remained detectable in the continuous phase of each emulsion system over three weeks of storage but were not detected at the o/w interface of oil droplets. The particle size of the SLN remained unchanged whereas their zeta potential increased in SDS and CTAB stabilized emulsions to a similar magnitude (+/− 68 mV) but opposite signs. The melting temperature and melting enthalpy of SLN decreased in emulsions indicating that part of the lipid matrix was dissolved by oil from the emulsion. Accordingly, a time-dependent transfer of crystalline triglycerides originating from the SLN into the oil phase of separated model emulsion systems was verified.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775717305046-fx1.jpg" width="450" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): S. Nazari, S.Z. Shafaei, B. Shahbazi, S. Chehreh Chelgani〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recent investigations indicated that using nanobubbles (NBs) in flotation separation of fine particles (〈25 μm) has several advantages; however, a detail study on performances of various flotation parameters (such as hydrodynamic variables and particle properties) and their impacts on recovery of coarse particles (〉100 μm) in the presence of NBs have not been fully understood. This work was explored how NBs can change impacts of Reynolds number, conventional flotation bubbles (CBs), air flow rate and particle sizes on flotation recovery of coarse particles (−425 + 106 μm). Several flotation experiments were carried out by using pure quartz in the presence and absence of NBs. Kendall’s tau (τ) as an accurate statistical method was introduced and applied through the provided dataset from the experiments to assess the impacts of NBs. In the absence of NBs; τ assessments demonstrated that there are negative correlations between particle size, air flow rate, Reynold number and recovery (τ ∼ −0.81, −0.18 and −0.12, respectively), and a positive relationship between CBs and recovery (τ ∼ 0.08). In general, results indicated that recovery of coarse particles was increased by ∼14% (on average) in the presence of NBs; however, the magnitude of relationships was not changed (just correlations between Reynolds and CBs vs. recovery were changed: τ ∼ −0.17 and 0.13, respectively). Assessing the simultaneous impacts of Re and CBs on recovery showed that in the presence of NBs; the highest recovery (on average) may receive in lower Re values and higher CB sizes in comparison with in the absence of NBs. Taking all these interactions into consideration, it can be concluded that increasing the rate of bubble-particle attachment and decreasing the impact of Re can be the main reasons for the enhancement of coarse particle recovery in the presence of NBs.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718307635-ga1.jpg" width="243" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Lev O. Filippov, Inna V. Filippova, Zineb Lafhaj, Daniel Fornasiero〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The adsorption mechanism of collector mixtures and the implication for mineral flotation are discussed in light of the results of a quantitative study of the flotation of fluorapatite and calcite with mixtures of fatty alcohol and oleate collectors. It was found that the recovery of fluorapatite and calcite floated with oleate improved considerably after addition of the fatty alcohol. With oleate alone, the low mineral flotation was attributed to a patchy oleate surface coverage and oleate dimers but with the collector mixture it was shown that the fatty alcohol co-adsorbs with oleate on the mineral surface and in a much larger quantity than when it was used alone. Spectroscopic analyses reveal that the amount of oleate adsorbed remains similar when added alone or in mixtures, which implies that the co-adsorption of the fatty alcohol is responsible for the improved mineral flotation. Replacement of oleate dimers with fatty alcohol-oleate complexes at the mineral surface may also explain the increase mineral hydrophobicity and flotation.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Infrared spectra of fluorapatite (Fap) with fatty alcohol (PX) or oleate (Ol) alone, and with Ol+½PX, Ol + PX or Ol+2PX mixtures at pH 9.0.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718308112-ga1.jpg" width="278" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Xudong Wang, Zhangjun Chen, Ke Li, Xiaodong Wei, Zhenbin Chen, Juan M. Ruso, Zhenghua Tang, Zhen Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, titanium dioxide particle was firstly modified with glutaraldehyde, and modification conditions, i.e. particle size (〈em〉d〈/em〉), active temperature (〈em〉T〈sub〉a〈/sub〉〈/em〉), modification temperature (〈em〉T〈sub〉m〈/sub〉〈/em〉), modification time (〈em〉t〈sub〉m〈/sub〉〈/em〉), pH value, aldehyde ethanol ratio (〈em〉R〈sub〉a〈/sub〉〈/em〉) and ethanol ratio (〈em〉R〈sub〉e〈/sub〉〈/em〉), were studied and optimized adopting grafting rate (〈em〉G〈sub〉r〈/sub〉〈/em〉) as the optimizing index, the ultraviolet-visible spectrophotometry as characterization method, and the obtained optimal modification conditions were 〈em〉d〈/em〉 = 3.3 μm, 〈em〉T〈sub〉a〈/sub〉〈/em〉 = 120 °C, 〈em〉T〈sub〉m〈/sub〉〈/em〉 = 45 °C, 〈em〉t〈sub〉m〈/sub〉〈/em〉 = 30 h, pH = 6.0, 〈em〉R〈sub〉a〈/sub〉〈/em〉 = 1:10 and 〈em〉R〈sub〉e〈/sub〉〈/em〉 = 100%. Under the optimal conditions, 〈em〉G〈sub〉r〈/sub〉〈/em〉 of glutaraldehyde arrived at 50%. Thereafter, a series of modified titanium dioxide with 〈em〉G〈sub〉r〈/sub〉〈/em〉 in the range of [8%, 46%] and with 〈em〉G〈sub〉r〈/sub〉〈/em〉 = 30% obtained from different modification conditions were adopted to study the immobilization of penicillin G acylase (PGA), during this process, the ultraviolet-visible spectrophotometry of 6-aminopenicillanic acid was conscripted as characterization method, the enzyme loading capacity (〈em〉ELC〈/em〉), the enzyme activity (〈em〉EA〈/em〉) and enzyme activity retaining ratio (〈em〉EAR〈/em〉) were explored, and results documented with the increase of 〈em〉G〈sub〉r〈/sub〉〈/em〉, 〈em〉ELC〈/em〉, 〈em〉EA〈/em〉 and 〈em〉EAR〈/em〉 increased. As 〈em〉G〈sub〉r〈/sub〉〈/em〉 kept as a similar level, 〈em〉ELC, EA〈/em〉 and 〈em〉EAR〈/em〉 also showed a similar value. Finally, the structure of titanium dioxide, glutaraldehyde modified titanium dioxide and PGA immobilized titanium dioxide was characterized by the flourier transform infrared spectroscopy (FTIR), and results exhibited aimed samples were obtained successfully.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718312792-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Priya A., Prabhakarn Arunachalam, Selvi A., Madhavan J., Abdullah M. Al-Mayouf〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present study demonstrates the synthesis of pure bismuth iron tungstate (BiFeWO〈sub〉6〈/sub〉) and tungsten oxide (WO〈sub〉3〈/sub〉) nanorods by simple co-precipitation and hydrothermal methods respectively. Likewise, BiFeWO〈sub〉6〈/sub〉/WO〈sub〉3〈/sub〉 nanocomposites of different compositions (1, 2 and 3 wt %) were fabricated via convenient wet-chemical route. The fabricated BiFeWO〈sub〉6〈/sub〉/WO〈sub〉3〈/sub〉 nanocomposites were investigated by numerous methods like X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDS) and photoelectrochemical (PEC) studies. Moreover, the photodegradation efficiency of the fabricated composites was demonstrated by photodegradation of Rhodamine B (RhB) under visible-light illumination. In particular, photodegradation results revealed the improved photocatalytic performance of 1% BiFeWO〈sub〉6〈/sub〉/WO〈sub〉3〈/sub〉 than the independent WO〈sub〉3〈/sub〉. This observed enhancement was credited to the restricted recombination rate of charge carriers by the composites leads to their separation. The as-synthesized BiFeWO〈sub〉6〈/sub〉/WO〈sub〉3〈/sub〉 photocatalytic materials were found to possess a reasonably good photostability, reusability and superior photocatalytic performances than the pure WO〈sub〉3〈/sub〉. Therefore, it can be used as a potential photocatalysts towards elimination of various organic pollutants present in aqueous environment. Further, a schematic charge transfer mechanism was also proposed in the present study.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718310781-ga1.jpg" width="211" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Zahra Mohammadizadeh Tahroudi, Amir Razmjou, Mojtaba Bagherian, Mohsen Asadnia〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Over the last decade, polydopamine (PDA) has attracted significant attention due to its material-independent coating ability, process simplicity, and its powerful capabilities for ad-layer formation. However, its long coating time (24 h) has limited its application in industrial scale. To address this issue, oxidants such as (NH〈sub〉4〈/sub〉)〈sub〉2〈/sub〉S〈sub〉2〈/sub〉O〈sub〉8,〈/sub〉 CuSO〈sub〉4,〈/sub〉 and NaIO〈sub〉4〈/sub〉 were introduced to enhance the coating kinetically. Although NaIO〈sub〉4〈/sub〉, among all the oxidants, was reported as the most efficient one, its high stoichiometric ratio of 2 between the oxidant and dopamine makes it costly and less attractive. Here, KMnO〈sub〉4〈/sub〉 is introduced as a new water-soluble oxidant which can substantially reduce the PDA coating to few minutes in a single reaction process with a chance to adjust its thickness without losing PDA intrinsic modification capability. At a KMnO〈sub〉4〈/sub〉/dopamine ratio of 0.4, a coating speed of 750 nm/h was achieved, which is 25 times higher than that of NaIO〈sub〉4〈/sub〉 at similar oxidant/dopamine ratio. The KMnO〈sub〉4〈/sub〉-assisted PDA coating was utilized to introduce an efficient and inexpensive method to convert glass materials to surfaces with durable UV shielding property. Finally, the reducibility and ad-layer formation ability of PDA layer were used to develop silver, copper, and ZIF8 composite PDA layer to adjust the UV protection level.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718307209-ga1.jpg" width="355" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Jie Zeng, Zili Li, Hao Peng, Xiaogang Zheng〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉ZnO-coated Sm〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 (Sm〈sub〉2〈/sub〉O〈sub〉3〈/sub〉@ZnO) nano-heterostructure was prepared for the visible light driven photodegradation of RhB. Core-shell Sm〈sub〉2〈/sub〉O〈sub〉3〈/sub〉@ZnO composites exhibited the enhanced photocatalytic activity compared with pure Sm〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 and ZnO nanoparticles alone for RhB removal. Sm〈sub〉2〈/sub〉O〈sub〉3〈/sub〉@ZnO with the ZnO thickness of around 10 nm presented the best photocatalytic capacity and slightly deactivated after five cycle times. It’s attributed to the extended light-harvesting capability of the core-shell heterostructure toward visible light region and the tunneled valence band holes of Sm〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 at the interface between Sm〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 core and ZnO shell. The attenuated photocatalytic activity of Sm〈sub〉2〈/sub〉O〈sub〉3〈/sub〉@ZnO in subsequent reuse process was ascribed to the change of chemical surface composition of Sm〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 under visible light irradiation. ESR results indicated that 〈sup〉〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/rad"〉〈/sup〉O〈sub〉2〈/sub〉〈sup〉−〈/sup〉 radical was main responsible for the photocatalytic performance of Sm〈sub〉2〈/sub〉O〈sub〉3〈/sub〉@ZnO.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718307647-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Sima Saeidy, Ali Nasirpour, Gholamreza Djelveh, Alina-Violeta Ursu, Cédric Delattre, Guillaume Pierre, Philippe Michaud〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Solutions of Asafoetida gum (2% w/w) were used to prepare oil in water emulsion with various oil/gum solution ratios (0.5, 1.0, 2.0, 3.0 and 4.0 v/v). Stability and rheological properties of the emulsions were examined over 28 days of storage at 20 °C. It was revealed that increasing oil volume fraction enhanced the emulsion stability. The results of creaming test showed that emulsions containing oil/gum solution ratio of more than 2.0 (v/v) displayed suitable emulsion stability. Droplet size measurements and microscopic images were representative of flocculation and coalescence with increasing oil volume fraction and time of storage. Emulsion droplet size was increased from 11.11 ± 0.99 μm to 64.01 ± 0.47 μm by increasing oil/gum solution from 0.5 to 4.0. Viscosity got higher values with increasing in oil volume fraction but reduced during the storage time. According to Herschel-Bulkely model, shear thinning behavior was determined for all emulsion samples.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718313311-ga1.jpg" width="280" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 562〈/p〉 〈p〉Author(s): Ping Jiang, Lei Zhang, Jijiang Ge, Guicai Zhang, Haihua Pei〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper investigates the effects of the SiO〈sub〉2〈/sub〉 nanoparticle mass concentration (w/v %) and oleic acid imidazoline mass fraction (w/w %) on the property of the emulsion stabilized jointly by SiO〈sub〉2〈/sub〉 and oleic acid imidazoline, with SiO〈sub〉2〈/sub〉 nanoparticles initially dispersed in different phases. In the experiment, the SiO〈sub〉2〈/sub〉 nanoparticle mass concentration in the aqueous or oil phases is fixed, and the surfactant mass fraction in oil is gradually increased, changing the emulsion from oil-in-water into water-in-oil. Moreover, in these cases, the required oil-soluble surfactant mass fraction for phase inversion is relatively low, with solid nanoparticles initially dispersed in water. Then, the surfactant mass fraction in oil is kept constant, and the emulsion type is changed from the water-in-oil into the oil-in-water by raising up the SiO〈sub〉2〈/sub〉 mass concentration in water or oil. Furthermore, under these conditions the solid nanoparticle mass concentration is higher with solid nanoparticles primarily dispersed in water than that in the case of solid nanoparticles initially placed in oil. The mechanism behind the emulsion type transition is analyzed by measuring the emulsion droplet size and rheological property of different emulsion systems. It is concluded that the difference regarding the initial dispersion medium of the solid nanoparticle affects the adsorption proportion of the solid nanoparticle and oleic acid imidazoline, the adsorption morphology, and the overall wettability of the interfacial stabilizer, which consequently impacts the property of the emulsion.〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): E.L. Brito, D.N. Gomes, C.C. Plá Cid, J.C.R. de Araújo, F. Bohn, L. Streck, J. L.C. Fonseca〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hybrid magnetic composites are materials with great potential for use in biomedicine and effluent treatments, as their organic phase may be used in the adsorption/release of pollutants/drugs and their magnetic properties for separation/transport of particulate systems based on these materials. In this work we obtained magnetic composite particles made of magnetite nanoparticles dispersed in a polymeric matrix resultant from the formation of interpolyelectrolyte complexes based on chitosan and poly(sodium 4-styrenesulfonate). Non-stoichiometric positive and negatively charged interpolyelectrolyte complexes were obtained and characterized via thermogravimetry, Fourier transform infrared spectroscopy, X-ray diffraction analysis, transmission electron microscopy, zeta potentiometry, and vibrating sample magnetometry. The samples obtained in this work showed that nanometric magnetite was incorporated to these systems and that the resultant composites were superparamagnetic. Preliminary tests showed that the composites may be used both in the sorption of cationic and anionic drugs.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718311981-ga1.jpg" width="261" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Hengwei Qiu, Jun Guo, Minqiang Wang, Shangdong Ji, Minghui Cao, Muhammad Amin Padhiar, Arshad Saleem Bhatti〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉There is an imperious demand on developing of self-cleaning surface enhanced Raman scattering (SERS) substrates, for eliminating traditional single-use substrates. Herein, ternary flexible membranes of reduced graphene oxide (r-GO) supporting Ag meso-flowers (Ag-MFs) and phenyl-modified graphitic carbon nitride nanosheets (PCNs) were fabricated for photocatalysis-driven self-cleaning SERS detection. In-situ growth of Ag-MFs with tunable morphology (such as coral-like, urchin-like, highly-branched, etc.) on r-GO surfaces provide abundant options for optimizing SERS detection limit, and thus, these PCNs/Ag-MFs@r-GO membranes exhibited strong SERS activity attributed to high density of intraparticle “hotspot” in Ag-MFs and preconcentration ability to probe molecules via π-π stacking. Among these membranes, the optimum PCNs/Ag-MFs@r-GO membrane shown a detection limit of 10〈sup〉−15〈/sup〉 M for rhodamine 6G (R6G) molecules, and this membrane could effectively remove probe molecules due to the excellent photocatalytic activity. We used R6G or methylene blue (MB) molecules for investigating the self-cleaning repeatability and stability of this PCNs/Ag-MFs@r-GO membrane, and the signal intensity for SERS detection maintained a high degree of 95% after five cycle-runs. Besides, this PCNs/Ag-MFs@r-GO membrane can be used as a high-efficiency filter membrane for simultaneous detection and purification in wastewater treatment (10 mg/mL imidacloprid solution as the example).〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718307106-ga1.jpg" width="214" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Daniel V. Gonçalves, Mayara A.G. Paiva, José C.A. Oliveira, Moises Bastos-Neto, Sebastião M.P. Lucena〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Monocomponent adsorption of hydrogen sulfide and multicomponent adsorption with CO〈sub〉2〈/sub〉 and CH〈sub〉4〈/sub〉 mixtures were predicted in two samples of commercial activated carbons. We perform Monte Carlo calculations in the grand canonical ensemble in representative slit-pores of each carbon material and proposed a new energy parameter for H〈sub〉2〈/sub〉S-carbon interaction from experimental adsorption heat in selected activated carbons. Further analysis of adsorption in representative pores demonstrated the importance of ultramicropores in H2S retention and a cooperative effect of CO〈sub〉2〈/sub〉 molecules favoring H〈sub〉2〈/sub〉S adsorption. To the best of our knowledge this is the first time that a method based on molecular simulation is proposed to predict H〈sub〉2〈/sub〉S adsorption on carbon. This study contributes to a better understanding of the role of pore size distribution and adsorption regimes in carbon materials.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571831241X-ga1.jpg" width="389" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Roshan Nazir, Uttaran Basak, Surojit Pande〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉RuO〈sub〉2〈/sub〉 nanorod (NR), an efficient and stable catalyst for hydrogen and oxygen evolution reaction is developed via wet-chemical route. Initially, a carbon slurry has been prepared using glucose and urea via heating at 140 °C for 6 h. During the preparation of carbon slurry Ru〈sup〉3+〈/sup〉 salt has been added to disperse homogeneously. Finally, calcination at 500 °C for 10 h has been performed using homogeneously distributed Ru〈sup〉3+〈/sup〉 ion in carbon slurry to get RuO〈sub〉2〈/sub〉 NR. The synthesized RuO〈sub〉2〈/sub〉 NR has been well characterized using FESEM, TEM, PXRD, and XPS analysis. The average aspect ratio of a single RuO〈sub〉2〈/sub〉 rod is ∼4.37. The synthesized RuO〈sub〉2〈/sub〉 NR has been used extensively as an electrocatalyst for hydrogen and oxygen evolution reaction. RuO〈sub〉2〈/sub〉 NR shows cathodic potential of −130 mV vs. RHE to achieve current density of 10 mA/cm〈sup〉2〈/sup〉 during hydrogen evolution reaction. Whereas, for oxygen evolution 1.508 V vs. RHE is required to generate 10 mA/cm〈sup〉2〈/sup〉 current density. Electrochemically active surface area and Tafel slope have been calculated to exhibit better activity of RuO〈sub〉2〈/sub〉 NR as compared to commercial RuO〈sub〉2〈/sub〉. The overall electrocatalysis mechanism has also been discussed in detail.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718313189-ga1.jpg" width="250" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): He Zhang, Chenlu Bao, Jinglei Yang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, hollow glass bubbles (HGBs) of about 70 μm with through-holes of about 5 μm were successfully separated from a commercialized product and were used as targets to be sealed/covered by GO sheets of size about 24 μm. Firstly, these HGBs were treated with poly(ethyleneimine) (PEI) cross-linked polydopamine (PDA) to positively charge their outer surface. After treatment, the outer surface of HGBs was uniformly deposited with PDA nano-particles. During sealing/covering process, GO sheets were successfully attracted to the PDA modified HGBs by electrostatic force between the negatively charged GO sheets and positively charged HGBs introduced by the deposited PDA nano-particles, and were anchored by PDA nano-particles at the outer surface to avoid sucking of GO sheets into HGBs through the holes. While most of HGBs were tightly sealed/covered, some of them were partially sealed due to the fractured or collapsed GO sheets on the through-holes.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718311506-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Jiamin Yu, Jian Zhang, Shiying Song, Hai Liu, Zizhang Guo, Chenglu Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Activated carbon (AC) derived from 〈em〉Phragmites Australis〈/em〉 (PA) with phosphoric acid activation as a low-cost adsorbent is extensively used in water treatment. In this study, a novel manganese formate hydrate (MFH) in-situ modified activated carbon (AC-MFH) has been proposed and investigated. The physical and chemical characteristics of adsorbents were characterized by N〈sub〉2〈/sub〉 adsorption/desorption, Fourier transform infrared (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results showed that AC-MFH had more microporous structures and surface oxygen-containing functional groups than AC. The Ni(II) adsorption behaviors of adsorbents were investigated by batch experiments, the results suggested that AC-MFH showed 20% higher Ni(II) adsorption capacity than that of AC and the associated adsorption isotherms and kinetics well fitted to the Langmuir model and pseudo-second-order model, respectively. The Ni(II) adsorption mechanisms of AC-MFH were investigated by FTIR and XPS analysis. These results indicated that the adsorption of Ni(II) mainly depended on the surface chemistry between the Ni(II) and surface oxygen-containing functional groups.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718313165-ga1.jpg" width="311" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): F. Varenne, H. Hillaireau, J. Bataille, C. Smadja, G. Barratt, C. Vauthier〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The development of dispersed material of small size in various fields is conditioned by their quality control. Size and surface properties such as zeta potential of dispersed materials employed in nanomedecine have been identified as key physico-chemical parameters as they may influence their 〈em〉in vivo〈/em〉 fate. These physico-chemical parameters can be determined using appropriate methods described in the ISO standards including dynamic light scattering and electrophoretic light scattering for evaluation of size and zeta potential respectively. Accurate measurements are paramount to ensure reliable results for material characterization. Reliability of measurements was ensured by a series of handling precautions and quality criteria for good measurements to be applied for the validation of the protocols. The present work was aimed to evaluate the application of validated protocols to characterize dispersed materials based on the analysis of quality criteria. The size measurement protocol was applied to evaluate size of a wide range of dispersed materials including polymer nanoparticles. However, this protocol was unsuitable for size evaluation of particles characterized by a high density and magnetic particles with size in the upper limit of the instrument. The validated protocol for zeta potential evaluation was suitable to evaluate zeta potential of polymer nanoparticles but not for the evaluation of zeta potential of dense nanoparticles.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571830983X-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉