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We report on the synthesis and characterization of composite semiconducting polymer – nanoparticle membranes for X-ray detection applications. The membranes are made of poly(vinyl alcohol) (PVA) organic polymer that is doped with ionic liquid (IL) to control its electrical conductivity. Tl 2 O 3 nanoparticles with different weight concentrations are added to the polymer, and membranes are produced using solution casting method. The nanoparticles are synthesized using a microwave assisted technique under controlled temperature and pressure, and their average size is 13.0 ∓ 1.9 nm. Structural and compositional tests confirm the fabrication of homogeneous polymer-nanoparticle films. Electrical impedance tests are conducted as a function of nanoparticle concentration and temperature for the membranes, and they reveal that the dc electrical resistance of the membranes decreases with increasing both nanoparticle concentration and temperature. The activation energy was found to increase with increasing nanoparticle concentration. The membranes are utilized as conductometric X-ray sensors, and their response increases with increasing X-ray generator voltage. The fabricated composite membranes exhibit semiconducting properties, easy to fabricate, low cost, and qualify practical device utilization in the X-ray dosimetry sector. • Composite membranes of polymer-nanoparticles were are synthesized • The membranes comprise of PVA, glycerol, and Tl 2 O 3 nanoparticles. • The nanoparticles were synthesized using a sol-gel modified method • Electrical characterization demonstrated that as nanoparticle concentration increases, the activation energy increase. • The membranes are suitable for potential applications in x-ray dosimetry field. [ABSTRACT FROM AUTHOR]

Abstract: The accurate conversion of dose to various materials used in clinical proton dosimetry to dose-to-water is based on fluence correction factors, accounting for attenuation of primary protons and production of secondary particles due to non-elastic nuclear interactions. This work aims to investigate the depth dose distribution and the fluence correction with respect to water or graphite at water equivalent depths (WED) in different target materials relevant for dosimetry such as polymethyl methacrylate (PMMA), graphite, A-150, aluminium and copper at 60 and 200MeV. This was done through a comparison between Monte Carlo simulation using MCNPX 2.5.0, analytical model calculations and experimental measurements at Clatterbridge Centre of Oncology (CCO) in a 60MeV modulated and un-modulated proton beam. MCNPX simulations indicated small fluence corrections for all materials with respect to graphite and water in 60 and 200MeV except for aluminium. The analytical calculations showed an increase in the fluence correction factor to a few percent for all materials with respect to water at 200MeV. The experimental measurements for 60MeV un-modulated beam indicated a good agreement with MCNPX. For the modulated beam the fluence correction factor was found to be decreasing below unity by up to few percent with depth for aluminium and copper but almost constant and unity for A-150. [Copyright &y& Elsevier]

Highlights • Sensitive and selective gas sensors fabricated using graphene and CuO nanorods. • The nanorods were deposited on either graphene/SiO2/Si substrates. • The sensors were found to be selective to H2S at concentrations as low as 10 ppm. • The sensors operate at room temperature which indicates their low power needs. Abstract This work reports on the fabrication of sensitive and selective gas sensors fabricated using graphene and/or copper oxide (CuO) nanorods. Herein, three batches of sensors were produced based on graphene/SiO 2 /Si, CuO nanorods, and graphene/SiO 2 /Si decorated with CuO nanorods. The nanorods were synthesized chemically and deposited on either graphene/SiO 2 /Si or glass substrates. The produced sensors were tested against H 2 S and H 2 gases. Sensors based on CuO/graphene/SiO 2 /Si were found to be selective to H 2 S and sensitive to concentrations as low as 10 ppm. Furthermore, the sensors could detect H 2 S at room temperature which indicates their low power consumption. The produced sensors have potential for applications in industries that include release of H 2 S such as petroleum refineries. [ABSTRACT FROM AUTHOR]

In this study, α-LiAlO2 was investigated for the first time as a Li-capturing positive electrode material to recover Li from aqueous Li resources. The material was synthesized using hydrothermal synthesis and air annealing, which is a low-cost and low-energy fabrication process. The physical characterization showed that the material formed an α-LiAlO2 phase, and electrochemical activation revealed the presence of AlO2* as a Li deficient form that can intercalate Li+. The AlO2*/activated carbon electrode pair showed selective capture of Li+ ions when the concentrations were between 100 mM and 25 mM. In mono salt solution comprising 25 mM LiCl, the adsorption capacity was 8.25 mg g−1, and the energy consumption was 27.98 Wh mol Li−1. The system can also handle complex solutions such as first-pass seawater reverse osmosis brine, which has a slightly higher concentration of Li than seawater at 0.34 ppm. [ABSTRACT FROM AUTHOR]

Direct alcohol fuel cells are deemed as green and sustainable energy resources; however, CO-poisoning of Pt-based catalysts is a critical barrier to their commercialization. Thus, investigation of the electrochemical CO oxidation activity (COOxid) of Pt-based catalyst over pH ranges as a function of Pt-shape is necessary and is not yet reported. Herein, porous Pt nanodendrites (Pt NDs) were synthesized via the ultrasonic irradiation method, and its CO oxidation performance was benchmarked in different electrolytes relative to 1-D Pt chains nanostructure (Pt NCs) and commercial Pt/C catalyst under the same condition. This is a trial to confirm the effect of the size and shape of Pt as well as the pH of electrolytes on the COOxid. The COOxid activity and durability of Pt NDs are substantially superior to Pt NCs and Pt/C in HClO4, KOH, and NaHCO3 electrolytes, respectively, owing to the porous branched structure with a high surface area, which maximizes Pt utilization. Notably, the COOxid performance of Pt NPs in HClO4 is higher than that in NaHCO3, and KOH under the same reaction conditions. This study may open the way for understanding the COOxid activities of Pt-based catalysts and avoiding CO-poisoning in fuel cells. [ABSTRACT FROM AUTHOR]

Fabrication and characterization of flexible semiconducting polymer-nanoparticles composite membranes for x-ray sensor device applications are presented in this work. Poly(vinyl alcohol) (PVA) polymer was initially doped with glycerol ionic liquid (IL) that permitted the control of its electrical resistivity. Metal-oxide Bi 2 O 3 nanoparticles were prepared by a modified sol-gel method. The average nanoparticle size was found to be 39 ± 10 nm. Thin films of flexible polymer membranes with different nanoparticle concentrations were prepared using a solution casting method. Compositional characterizations revealed the formation of homogeneous polymer-nanoparticle membranes. Electrical impedance measurements of the membranes were performed for the membranes in a form of capacitor structure as a function of temperature and nanoparticle concentration. The measurements demonstrated that the membranes could be modeled with a pair of parallel resistor and capacitor that were assigned to the contributions of grain boundaries as well as the region of electron depletion in the membrane. As nanoparticle concentration increases, the resistivity and activation energy decrease. Current-voltage measurements demonstrated that the produced membranes function as x-ray sensors, and their response increases as a function of nanoparticle concentration. The produced membranes exhibit semiconducting properties that qualify them as potential candidates for device applications in the field of x-ray dosimeter. • Semiconducting polymer-nanoparticles composite membranes were presented. • The membranes consist of PVA, glycerol ionic liquid, and Bi 2 O 3 nanoparticles. • The nanoparticles were prepared by a modified sol-gel method. • As nanoparticle concentration increases, the resistivity and activation energy decrease. • The membranes are qualified as potential candidates for x-ray dosimeter. [ABSTRACT FROM AUTHOR]

This paper discusses the state of the art in the application of self-healing silicone-based materials for outdoor high-voltage insulation. Both the dynamic behavior of the dimethyl side groups of silicone rubber and the diffusion of a bulk siloxane to maintain low surface energy are respectively reported as intrinsic mechanisms responsible for the self-healing of silicone rubber. Localization, temporality, mobility, and the type of synthesis are the aspects defining the efficiency of the self-healing ability of silicone rubber. In addition, the deterioration of the self-healing ability with filler loaded into silicone rubber insulation housing composites is discussed. Taking the self-healing property into consideration among the other properties of silicone rubber insulators, such as tracking and erosion resistance, can be a useful design practice at the material development stage. Hydrophobicity retention, recovery, and transfer measurements are discussed as useful indicators of the self-healing ability of silicone rubber. Nevertheless, there remains a need to standardize them as design tests at the material development stage. The paper is intended to shed the light on the hydrophobicity recovery, a key material design parameter in the development of silicone rubber outdoor insulating composites, similar to the tracking and erosion resistance. [ABSTRACT FROM AUTHOR]

Resource recovery from natural reserves is appealing and Li extraction from different brines is in the forefront. Li extraction by membranes is reviewed in the literature much more than electrochemical processes. However, a very recent review thoroughly discussed Li recovery by electrochemically switchable ion exchange (ESIX). This paper reviews Li recovery by both charge transfer processes, namely electrodialysis (ED), and electro-sorption processes, namely capacitive deionization (CDI). It also reviews ESIX with a focus on performance matrices and includes comments on the technology readiness of each separation technique. These processes exhibit promising perspectives on the separation and recovery of Li both selectively and non-selectively from simulated brine solutions and Li salt solutions. Readers are provided with guidelines to choose between the processes, depending on the applied voltage, current density, specific energy consumption and purity of recovered Li. Most electrochemical lithium capturing systems (ELiCSs) have been tested at the lab scale. Therefore, future research should be directed toward pilot-scale development and parameter optimization. Furthermore, we urge the ELiCSs research community to report information in a standard form that allows meaningful comparisons and insights into the systems. Unlabelled Image • SED and BMED are the most appropriate methods for high recovery of Li+ at low SEC. • ESIX technology for Li recovery considered extracting Li from other liquid Li resources. • CDI is an advancement of ESIX since it utilizes intercalating electrodes with IEMs. • ELiCSs need to be studied at pilot-scale using continuous processes. • Future ELiCSs research needs to focus on using natural Li liquid resources. [ABSTRACT FROM AUTHOR]

• Composite flexible polymer membranes of PVA and CuO nanoparticles were synthesized. • The membranes were fabricated at different nanoparticles' concentrations. • The activation energy of the membranes decreased with nanoparticle concentration. • X-ray response of the membrane increased with increasing nanoparticle concentration. • The membranes are potential candidates for the applications of x-ray detection. Flexible membranes of poly(vinyl alcohol) (PVA) polymer and CuO nanoparticles for x-ray detection applications are reported in this work. PVA represents a polymer matrix for nanoparticles, and its flexibility and electrical conductivity are enhanced by addition of glycerol (GL) plasticizer. Nanoparticles of an average size of 6.3 ∓ 2.4 n m are produced by a solvothermal method and added to the PVA + GL solution with different concentrations. The flexible membranes are fabricated by solution casting on glass substrates. The effect of blending of PVA + GL with nanoparticles on different characteristics of the membranes including the flexibility as well as the melting, glass transition, and degradation temperatures are tested by differential scanning calorimetry, thermal gravimetric analysis, as well as both Raman and Fourier-transform infrared spectroscopy. Electrical impedance tests reveal that both dc resistance and activation energy decrease with increasing temperature as well as nanoparticle concentration. The produced membranes reveal electrical response to x-ray due to the presence of CuO nanoparticles, and this response rises with x-ray generator voltage. The results presented in this study specify that the produced membranes are easy to produce with low cost, thus, they represent potential candidates for practical applications including x-ray detection. [ABSTRACT FROM AUTHOR]