The kinetics of oxidation of Ni (Ni + co)-Nbc superalloys represented by the alloy Ni-Nbc and (Ni + co)-Nbc was studied. The alloys were studied in the cast state. It was found that the alloys oxidize according to a p...
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The kinetics of oxidation of Ni (Ni + co)-Nbc superalloys represented by the alloy Ni-Nbc and (Ni + co)-Nbc was studied. The alloys were studied in the cast state. It was found that the alloys oxidize according to a parabolic law. The analysis of diffusion-oxidation processes at a temperature of 1100 degrees c in air indicates an increase in heat resistance as a result of intensification of scale sintering and the formation on the surface of superalloys of a diffusion barrier layer of chromium, aluminum, and niobium oxides. The research result determines the prospects of creating industrial alloys for power engineering based on Ni (Ni + co)-Nbc superalloys.
In this paper, a comparative study is presented on the application of General-purpose computing on Graphics Processing Units for solving the point reactor kinetics equations through the utilization of the 4th Order Ru...
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In this paper, a comparative study is presented on the application of General-purpose computing on Graphics Processing Units for solving the point reactor kinetics equations through the utilization of the 4th Order RungeKutta (RK4) method using the programming languages c and Python. Sequential and parallel algorithms of the RK4 method were developed in c/c++ and Python, with parallel algorithms specifically designed to operate on Graphics Processing Units (GPUs) utilizing the NVIDIA compute Unified Device Architecture (cUDA) as the programming platform. As an experiment, the execution time for the sequential and parallel algorithms were compared for a reactivity value of rho = 0.003 and a simulation time of t = 100 s. The parallel c and Python algorithms achieved, respectively, speedups of 9.33 and 409.7 when comparing the execution time on the best GPU utilized (RTX 3070Ti) with the best cPU (3600XT), while still maintaining numerical precision.
The selective adsorption mechanism of c-cdS2 2 monolayer was revealed using density functional theory. The results show that c-cdS2 2 has good adsorption properties for SO2, 2 , NO, NH3, 3 , NO2 2 and cl2, 2 , and all...
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The selective adsorption mechanism of c-cdS2 2 monolayer was revealed using density functional theory. The results show that c-cdS2 2 has good adsorption properties for SO2, 2 , NO, NH3, 3 , NO2 2 and cl2, 2 , and all of them are chemisorbed. Under the adsorption of different gas molecules, the electronic structure of c-cdS2 2 changed to varying degrees, which provided a theoretical basis for the use of c-cdS2 2 as a gas sensor or scavenger for these gases.
Microbial communities are fundamental components driving critical biogeochemical carbon (c), nitrogen (N) and sulfur (S) cycles in groundwater ecosystems. The reduction-oxidation (redox) potential is one important env...
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Microbial communities are fundamental components driving critical biogeochemical carbon (c), nitrogen (N) and sulfur (S) cycles in groundwater ecosystems. The reduction-oxidation (redox) potential is one important environmental factor influencing the microbial community composition. Here, we developed a bio-trap method using in-situ sediment as a matrix to collect aquifer sediment samples and evaluate the response of microbial composition and c/N/S cycling functions to redox variations created by providing sole O-2, joint O-2 and H-2, and sole H-2 to three wells. Illumina sequencing analyses showed that the microbial communities in the bio-trap sediment could respond quickly to redox changes in the wells, demonstrating that this bio-trap method is promising for detecting microbial variation in the aquifer sediment. The microbial metabolic functions related to c, N and S cyclings and organic pollutants degradation were predicted by the Kyoto Encyclopedia of Genes and Genomes (KEGG) approach. It was found that the joint O-2 and H-2 injection produced medium oxidation-reduction potential (ORP -346 and -614 mV) and enhanced more microbial functions than sole O-2 or H-2,H- which mainly include oxidative phosphorylation, most carbon source metabolism, various pollutants degradation, and nitrogen and sulfur metabolism. Moreover, the functional genes encoding phenol monooxygenase, dioxygenase, nitrogen fixation, nitrification, aerobic and anaerobic nitrate reductase, nitrite reductase, nitric oxide reductase, and sulfur oxidation increased. These findings tell us the contaminant bioremediation and N, S metabolism can be promoted by adjusting ORP realised by injecting joint O-2 and H-2.
To realize high-capacity Ge anodes for next-generation Li+-ion batteries, a multilayer anode with a c(top)/Ge(middle)/c(bottom) structure wasdeveloped, where nanostructured amorphous Ge (a-Ge) and amorphous-like carbo...
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To realize high-capacity Ge anodes for next-generation Li+-ion batteries, a multilayer anode with a c(top)/Ge(middle)/c(bottom) structure wasdeveloped, where nanostructured amorphous Ge (a-Ge) and amorphous-like carbon films with a grain size of 10-20 nm were depositedsequentially by high-pressure Ar sputtering at 500 mTorr. compared with the a-Ge anode, the c(top)/a-Ge(middle)/c(bottom) multistacking layeranode showed improved capacity degradation for repeated lithiation/delithiation reactions and achieved a high capacity of 910 mAh g(-1)with nocapacity fading after 90 cycles at a c-rate of 0.1.(c) 2024 The Author(s). Published on behalf of The Japan Society of Applied Physics by IOPPublishing Ltd
Here, an approach to produce a hierarchical porous Fe-N-c@TABOH catalyst with densely accessible high intrinsic active FeNx sites is proposed. The method involves a single-step pyrolysis of Zn/Fe-zeolitic imidazolate ...
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Here, an approach to produce a hierarchical porous Fe-N-c@TABOH catalyst with densely accessible high intrinsic active FeNx sites is proposed. The method involves a single-step pyrolysis of Zn/Fe-zeolitic imidazolate framework (Zn/Fe-ZIF-H) with tetrabutylammonium hydroxide (TABOH) micelles, which is obtained by utilizing TABOH as a structural template and electronic mediator at room temperature for a brief duration of 16 min. Notably, the yield of Zn/Fe-ZIF-H is 3.5 times that of Zn/Fe-ZIF-N prepared by conventional method. Results indicate that in addition to expediting synthesis and increasing yield of the Zn/Fe-ZIF-H, the TABOH induces a hierarchical porous structure and fosters the formation of more and higher intrinsic active FeNx moieties in Fex-N-c@TABOH, showing that TABOH is a multifunctional template. crucially, the increased mesoporosity/external surface area and optimized microenvironment of Fe-N-c@TABOH significantly enhance ORR activity by facilitating the formation of high intrinsic active FeNx sites, increasing accessible FeNx sites, and reducing mass transfer resistance. Through structure tailoring and microenvironment optimization, the resulting Fe-N-c@TABOH exhibits superior ORR performance. DFT calculation further validates that the synergistic effect of these two factors leads to low ORR barrier and optimized *OH adsorption energy. This study underscores the importance of structure and electronic engineering in the development of highly active ORR catalysts. A simple rapid strategy to fabricate a hierarchical porous Fe-N-c@TABOH catalyst with densely accessible high intrinsic active FeNx sites is proposed. Benefit from structure tailoring and microenvironment optimization, the resulting Fe-N-c@TABOH showed superior ORR performance, offering an exceptionally high MFc power density of 830.1 +/- 5.2 mWm-2, which is comparable to that of the Pt/ccatalyst. image
In this study, SiO@graphite@c@Al2O3 (SiO@G@c@A) composites are synthesized by varying the content of Al2O3, and their morphology and structure and their electrochemical performance are investigated in detail. The resu...
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In this study, SiO@graphite@c@Al2O3 (SiO@G@c@A) composites are synthesized by varying the content of Al2O3, and their morphology and structure and their electrochemical performance are investigated in detail. The results indicate that the SiO/G@c@A-2 composite exhibits a specificcapacity of 977.1 mA h g(-1) at a current density of 0.1 A g(-1) with a coulombic efficiency of 71.15%. Even after 100 cycles at a current density of 0.5 A g(-1), it retains a delithiated specificcapacity of 640.7 mA h g(-1) and a capacity retention rate of 73.56%. Moreover, when the current density is raised to 2 A g(-1), it maintains a delithiated capacity of 568.4 mA h g(-1) and a capacity retention rate of 58.51%. The excellent electrochemical performance is ascribed to the synergistic effect of different components. The inclusion of graphite enhances overall conductivity while mitigating the volume expansion of the SiO. The application of asphalt pyrolyticcarbon as a coating effectively isolates the SiO from the electrolyte, further reducing volume expansion and enhancing conductivity. The introduction of Al2O3 can absorb trace amounts of hydrogen fluoride (HF) generated during charge and discharge processes. Additionally, it facilitates the formation of an AlF3 film on the particle surfaces, which hinders and decelerates electrolyte dissolution into the electrode. The prepared composites exhibit promising prospects as lithium-ion battery anode materials. [GRAPHIcS] .
Needled composites have stronger interlaminar properties compared to two-dimensional fiber composite structures due to the introduction of z-directional fibers in the fiber composite layup. An effective multi-scale fi...
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Needled composites have stronger interlaminar properties compared to two-dimensional fiber composite structures due to the introduction of z-directional fibers in the fiber composite layup. An effective multi-scale finite element model is developed in this paper for the complex structure of needle-punched composites. Three scales, namely fRVE, pRVE, and lRVE, are modeled from the fiber scale, the delamination scale, and the laminate scale. using ABAQUS, periodic boundary conditions are applied to the RVEs at different scales to obtain the effective mechanical properties of various RVEs. Meanwhile, the effect of needling density on the needled composites is predicted by applying the above multi-scale model. The increase of needling density can enhance the out-of-plane effective mechanical properties of the composites, but it also weakens the in-plane effective mechanical properties. The maximum error of the elastic modulus calculation is 17.68% with that of the reference, thus verifying the rationality of the multi-scale model.
In the quest to enhance Zn-air batteries (ZABs) for operating across a wide spectrum of temperatures, synthesizing robust oxygen electrocatalysts is paramount. conventional strategies focusing on orbital hybridization...
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In the quest to enhance Zn-air batteries (ZABs) for operating across a wide spectrum of temperatures, synthesizing robust oxygen electrocatalysts is paramount. conventional strategies focusing on orbital hybridization of d-d and p-d aim to moderate the excessive interaction between the d-band of the transition metal active site and oxygen intermediate, yet often yield suboptimal performance. Herein, an innovative s-block metal modulation is reported to refine the electronic structure and catalytic behavior of co & horbar;Nccatalysts. Employing density functional theory (DFT) calculations, it is revealed that incorporating Mg markedly depresses the d-band center of co sites, thereby fine-tuning the adsorption energy of the oxygen reduction reaction (ORR) intermediate. consequently, the Mg-modified co & horbar;Nccatalyst (Mgco & horbar;Nc) unveils remarkable intrinsic ORR activity with a significantly reduced activation energy (Ea) of 10.0 kJ mol(-1), outstripping the performance of both co & horbar;Nc (17.6 kJ mol(-1)), benchmark Pt/c (15.9 kJ mol(-1)), and many recent reports. Moreover, ZABs outfitted with the finely tuned Mg0.1co0.9 & horbar;Nc realize a formidable power density of 157.0 mW cm(-2), paired with an extremely long cycle life of 1700 h, and an exceptionally minimal voltage gap decay rate of 0.006 mV h(-1). Further, the Mg0.1co0.9 & horbar;Nc-based flexible ZAB presents a mere 2% specificcapacity degradation when the temperature fluctuates from 25 to -20 degrees c, underscoring its robustness and suitability for practical deployment in diverse environmental conditions.
The use of ozone in food processing has become an eco-friendly, cost-effective way to manage insect pests and improve grain quality. The present study examined the efficacy of different ozone concentrations (500-1000 ...
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The use of ozone in food processing has become an eco-friendly, cost-effective way to manage insect pests and improve grain quality. The present study examined the efficacy of different ozone concentrations (500-1000 ppm), exposure time (2-6 h), and grain moisture content (11-15%, wb) on mortality of different developing stages (egg, larvae, and pupae) and adult of callosobruchus maculatus. Treated Mung bean was also analyzed for in-vitro protein digestibility (IVPD), grain hardness, and germination rate. A comparison between untreated (control) and treated mung bean samples at optimized conditions was conducted to determine the influence of ozone on proximate and mineral analysis, thermal and pasting properties. c. maculatus pupae and adults were least susceptible to ozonation, with mortality rates of 11.11 and 13.04-100%, respectively. In the optimal condition of 11.17% grain moisture content, 1000 ppm ozone concentration, and 2 h exposure time, mortality of different life stages (egg, larvae, pupae, and adults) of c. maculatus was calculated as 104.07%, 90.15%, 86.82%, and 83.55%, respectively. The corresponding values of IVPD, hardness, and grain germination were 67.85%, 57.43 N, and 87.74%, respectively. There was a noticeable decrease in protein, fat, and mineral content in ozone-treated mung bean compared to the control. Furthermore, enhancement in thermal and pasting properties of ozonated mung beans suggest that ozone can be utilized to develop high quality grain products' while ensuring their safety.
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