39 research outputs found
Fatigue Test and Unified Fatigue Life Calculation of Q460C Steel Notched Plates
No full textIn the present study, a total of 20 fatigue tests on notched plates of Q460C steel were carried out, where the effects of relative stress amplitude, Δσ/fy, and relative nominal maximum stress, σmax/fy, on the fatigue life of these notched plates were carefully examined. Theoretical analyses and numerical simulations were subsequently conducted, based on an ellipsoidal fracture model originally proposed by the second author, which has been validated for use as a fracture criterion of fatigue crack, to investigate the fatigue cracking in the Q460C steel notched plates. The theoretical model was further developed to estimate the fatigue life of the Q460C steel notched plates using a unified crack growth approach originally proposed by the second author. Based on the theoretical and simulated results, the accuracy of the unified crack growth approach, and the allowable stress fatigue life formula recommended in China’s code GB50017-2017, were assessed. The comparisons indicate that the unified crack growth approach is able to provide a reliable fatigue life assessment for the Q460C steel notched plates
Algorithm and simulation of automatic recommendation based on information requirements
No full textInformation acquisition is the prerequisite for command decision-making. In the era of big data filled with massive information, the useful information is submerged in useless information. How to efficiently obtain the useful information needed by command personnel is the key to improve operational command effectiveness. The author uses the information automatic recommendation algorithm, on the basis of the information requirements proposed by the commander, extracts the useful information and automatically recommends to commander based on the text similarity. It can effectively improve the timeliness of information acquisition and command decision-making, and thus improve the effectiveness of combat command
Effect of Roasting Temperatures on the Properties of Bitter Apricot (<i>Armeniaca sibirica</i> L.) Kernel Oil
No full textVitamin C Inhibits Aggravated Eryptosis by Hydrogen Peroxide in Glucose-6-Phosphated Dehydrogenase Deficiency
No full textBackground/Aims: The study was aimed to investigate if vitamin C could exert protective effects on development of eryptosis caused by glucose-6-phosphate dehydrogenase (G6PD) deficiency and hydrogen peroxide. Methods: Isolated erythrocytes with different G6PD activity (normal or deficient) were divided into various groups treated by either Vitamin C or H2O2. Phosphatidylserine (PS) extroversion rate was detected by Annexin V binding. The intracellular Ca2+ concentration was detected by Fluo3-fluorescence, and western blot was used to detect the expression of apoptosis factor caspase 3. Results: Compared with the blank group, the PS extroversion rate (P 2+ concentration (P P 2O2. Then the index of eryptosis significantly decreased after erythrocytes were treated with Vitamin C (1 mg/ml) for 30 min (all P Conclusion: Vitamin C could effectively inhibit the eryptosis contributed by H2O2 oxidative stress, and the suppression on eryptosis with G6PD normal activity was more effective than that with G6PD deficiency
Thermal-Hydraulic-Mechanical Coupling Simulation of CO<sub>2</sub> Enhanced Coalbed Methane Recovery with Regards to Low-Rank but Relatively Shallow Coal Seams
No full textCO2 injection technology into coal seams to enhance CH4 recovery (CO2-ECBM), therefore presenting the dual benefit of greenhouse gas emission reduction and clean fossil energy development. In order to gaze into the features of CO2 injection’s influence on reservoir pressure and permeability, the Thermal-Hydraulic-Mechanical coupling mechanism of CO2 injection into the coal seam is considered for investigation. The competitive adsorption, diffusion, and seepage flowing of CO2 and CH4 as well as the dynamic evolution of fracture porosity of coal seams are considered. Fluid physical parameters are obtained by the fitting equation using MATLAB to call EOS software Refprop. Based on the Canadian CO2-ECBM project CSEMP, the numerical simulation targeting shallow low-rank coal is carried out, and the finite element method is used in the software COMSOL Multiphysics. Firstly, the direct recovery (CBM) and CO2-ECBM are compared, and it is confirmed that the injection of CO2 has a significant improvement effect on methane production. Secondly, the influence of injection pressure and temperature is discussed. Increasing the injection pressure can increase the pressure difference in the reservoir in a short time, so as to improve the CH4 production and CO2 storage. However, the increase in gas injection pressure will also lead to the rapid attenuation of near-well reservoir permeability, resulting in the weakening of injection capacity. Also, when the injection temperature increases, the CO2 concentration is relatively reduced, and the replacement effect on CH4 is weakened, resulting in a slight decrease in CBM production and CO2 storage
Study on the evolution of permeability properties of limestone under different stress paths
No full textStress path change has a great relationship with the effect of deformation and strength of rock. However, the underground rock body is in the engineering environment where the stress field, seepage field, and other fields are coupled to change, the law of fluid flow in the rock body is complex and variable. The change in the stress field has an important effect on the seepage characteristics of rock body; therefore, it is necessary to study the pattern of rock permeability evolution pattern by different stress paths. This study is based on the study of limestone, conducting triaxial unloading seepage mechanics experiments, the evolution of permeability properties of limestone specimens was analyzed based on the test results. The results show that in the conventional triaxial loading seepage test, the permeability of the limestone decreases before the rock stress reaches the peak intensity and increases after that. Increasing axial pressure unloading surrounding pressure compression section, permeability loss rate and effective stress are in line with the changing law of Gaussian distribution function. Under the action of constant axial pressure unloading surrounding pressure, with the increase in unloading amount, the permeability rate of change appears to increase slowly, and in the late stage of unloading section, the permeability rate of change appears to surge. Unloading section permeability change rate and cumulative unloading amount are in line with the law of change of the exponential function. Creep unloading pressure seepage test found that unloading pressure stage strain-time and permeability-time evolution characteristics are in line with the exponential rule of change. The experimental results of this study can provide an important experimental and theoretical basis for the permeability analysis of low-permeability rock body under complex stress conditions in underground engineering
Heat Transfer Performance of Capillary Heat Exchangers in Circular Tunnel Lining during Intermittent Operation
No full textTunnel ground-source heat pumps are effective in solving the thermal pollution problem in subway tunnels. A capillary-tube heat exchanger (CHE) is used as the front-end heat exchanger of the tunnel ground-source heat pump system because of its corrosion resistance, easy bending, good heat transfer performance, and compactness. In this study, a CHE fluid-thermal coupling heat transfer model is established based on a demonstration project, and a CHE simulation system is built on the TRNSYS platform to analyze the heat transfer performance of the CHE in tunnel linings under continuous and intermittent operation. When the run-time ratio increases from 1/3 to 1, the average daily heat flux of CHE in the cooling and heating seasons decreases from 100.59 W/m2 and 87.42 W/m2 to 78.14 W/m2 and 68.62 W/m2 after 7 days, respectively, whereas the inner surface temperature of the surrounding rock increases and decreases in the cooling and heating seasons, respectively. The results show that intermittent operation can significantly improve the heat transfer performance of the heat exchanger and help alleviate the problem of cold and heat accumulation in the rock surrounding the tunnel
in Li‐Ion Battery Anodes?
No full textSilicon oxide (SiOx ), inheriting the high-capacity characteristic of silicon-based materials but possessing superior cycling stability, is a promising anode material for next-generation Li-ion batteries. SiOx is typically applied in combination with graphite (Gr), but the limited cycling durability of the SiOx /Gr composites curtails large-scale applications. In this work, this limited durability is demonstrated in part related to the presence of a bidirectional diffusion at the SiOx /Gr interface, which is driven by their intrinsic working potential differences and the concentration gradients. When Li on the Li-rich surface of SiOx is captured by Gr, the SiOx surface shrinks, hindering further lithiation. The use of soft carbon (SC) instead of Gr can prevent such instability is further demonstrated. The higher working potential of SC avoids bidirectional diffusion and surface compression thus allowing further lithiation. In this scenario, the evolution of the Li concentration gradient in SiOx conforms to its spontaneous lithiation process, benefiting the electrochemical performance. These results highlight the focus on the working potential of carbon as a strategy for rational optimization of SiOx /C composites toward improved battery performance.This work was supported by the School Research Startup Expenses of Harbin Institute of Technology (Shenzhen) (DD29100027), the High-level Talents’ Discipline Construction Fund of Shandong University (31370089963078), the National Natural Science Foundation of China (52175300, 52105329), and the project NANOGEN (PID2020-116093RB-C43) funded by MCIN/ AEI/10.13039/501100011033/. ICN2 acknowledges funding from Generalitat de Catalunya 2017 SGR 327, the Severo Ochoa program from Spanish MCIN / AEI (CEX2021-001214-S), and the CERCA Programme / Generalitat de Catalunya. This work was supported by MCIN with funding from European Union NextGenerationEU (PRTR-C17.I1) and Generalitat de Catalunya. Part of the present work has been performed in the framework of Universitat Autònoma de Barcelona Materials Science PhD program. G.Z. thanks the China Scholarship Council for the scholarship support.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2021-001214-S)Peer reviewe
