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Numerical simulation of temperature field in surrounding rock of coal mining face based on cyclic advancement algoritm

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Meitan Xuebao/Journal of the China Coal Society 2025年第1期50卷 409-420页

作者： Qin, Yueping Guo, Mingyan Tang, Fei Liu, Qiang Zhang, Jixin Hou, Haonan Zhao, Wei School of Emergency management and Safety Engineering China University of Mining and Technology -Beijing Beijing100083 China

With the increasing depletion of shallow coal resources, deep mining has become the new normal for coal resources development. The high temperature and high humidity thermal environment in deep mines jeopardizes the health of operators, increases the failure rate of electromechanical equipment, and is very likely to cause safety accidents underground. As one of the most important heat sources in the coal mining face, the heat dissipation calculation of high-temperature surrounding rock has long relied on fitting empirical equations and lacks a scientific and reasonable calculation *** on Fourier's law and the law of energy conservation, a two-dimensional non-stationary mathematical model of surrounding rock temperature field in the coal mining face was established, and the model was discretized by the finite volume method. Then a new algorithm of cyclic advancing was proposed to simulate the actual coal cutting process by the intermittent movement of the coordinates, which significantly improves the calculation accuracy of heat dissipation of high-temperature surrounding rock in coal mining face under dynamic advancing conditions. Subsequently, the cyclic advancing algorithm process was introduced in detail with a single node as an example, and the numerical solution program was developed independently based on the Visual Studio programming platform. Finally, we carried out numerical simulation and verification of the temperature field and heat dissipation law of the high-temperature surrounding rock in the coal mining face in conjunction with the engineering background. The results show that: the simulation results are basically consistent with the trend of the field measured data, and the average relative error of the model is 6.15%. During the continuous cycle of coal cutting, the temperature field of the surrounding rock shows the characteristics of cyclic change. Within a cycle, the heat dissipation intensity of the surrounding rock in each region reac

关键词： Coal mines

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Depression, anxiety, and cardiac morbidity outcomes after coronary artery bypass surgery： a contemporary and practical review

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Journal of Geriatric Cardiology 2012年第2期9卷 197-208页

作者： Phillip J Tully Robert A Baker Department of Surgery Flinders Medical Centre and Flinders University of South Australia 3 Flinders Drive Bedford Park SA 5042 Australia School of Psychology University of Adelaide Hughes Building North Terrace Adelaide SA 5005 Australia Discipline of Psychiatry The University of Adelaide Eleanor Harold Building Frome Road Adelaide SA 5005 Australia heart failure self management program Ambulatory and Primary Healthcare Directorate Hampstead Rehabilitation Centre 207 Hampstead Road Northfield SA 5085 Australia

Research to date indicates that the number of coronary artery bypass graft （CABG） surgery patients affected by depression （i.e., major, minor, dysthymia） approximates between 30% and 40% of all cases. A longstanding empirical interest on psychosocial factors in CABG surgery patients highlights an association with increased risk of morbidity in the short and longer term. Recent evidence suggests that both depression and anxiety increase the risk for mortality and morbidity after CABG surgery independent of medical factors, although the behavioral and biological mechanisms are poorly understood. Though neither depression nor anxiety seem to markedly affect neuropsy- chological dysfunction, depression confers a risk for incident delirium. Following a comprehensive overview of recent literature, practical advice is described for clinicians taking into consideration possible screening aids to improve recognition of anxiety and depression among CABG surgery patients. An overview of contemporary interventions and randomized, controlled trials are described, along with suggestions for future CABG surgery research.

关键词： Depression Depressive disorder Coronary artery bypass Coronary artery disease Antidepressive agents Anxiety

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Senescent mesenchymal stem/stromal cells and restoring their cellular functions

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World Journal of Stem Cells 2020年第9期12卷 966-985页

作者： Qing-Shu Meng Jing Liu Lu Wei Hui-Min Fan Xiao-Hui Zhou Xiao-Ting Liang Shanghai heart failure Research Center Shanghai East HospitalTongji University School of MedicineShanghai 200120China Research Center for Translational Medicine Shanghai East HospitalTongji University School of MedicineShanghai 200120China Institute of Integrated Traditional Chinese and Western Medicine for Cardiovascular Chronic Diseases Tongji University School of MedicineShanghai 200120China Department of heart failure Shanghai East HospitalTongji University School of MedicineShanghai 200120China Institute for Regenerative Medicine Shanghai East HospitalSchool of Life Sciences and TechnologyTongji UniversityShanghai 200120China

Mesenchymal stem/stromal cells(MSCs)have various properties that make them promising candidates for stem cell-based therapies in clinical *** include self-renewal,multilineage differentiation,and ***,recent studies have confirmed that aging is a vital factor that limits their function and therapeutic properties as standardized clinical *** the features of senescence and exploration of cell rejuvenation methods are necessary to develop effective strategies that can overcome the shortage and instability of *** review will summarize the current knowledge on characteristics and functional changes of aged ***,it will highlight cell rejuvenation strategies such as molecular regulation,noncoding RNA modifications,and microenvironment controls that may enhance the therapeutic potential of MSCs in clinical settings.

关键词： Mesenchymal stem cells Senescence Features Function Rejuvenation strategy

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Framework for Measuring the Resilience of Utility Poles of an Electric Power Distribution Network

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International Journal of Disaster Risk Science 2019年第2期10卷 270-281页

作者： MdMorshedul Alam Berna Eren Tokgoz Seokyon Hwang Department of Industrial Engineering Lamar UniversityBeaumontTX77710USA Construction management program Lamar UniversityBeaumontTX77710USA

The utility poles of an electric power distribution system are frequently damaged by wind-related *** study notes that the wooden poles are particularly vulnerable to such disasters and the failures of the poles can cause a network-level failure leading to short-or longterm power outages. To mitigate the problem, this study proposes a framework for measuring the resilience of the wooden utility poles based on the angular deflection of a pole due to the wind force. Given the existing inclination angle of a pole, the angular deflection is measured by finite element analysis using ANSYS~? Workbench^1 to determine the resilience area under various wind speeds. For this, the conditions of load and support for a pole, which are called boundary conditions in ANSYS~?, are generated. The proposed framework also includes an approach to cost–benefit analysis that compares different strategies for corrective action. The results of the case study in which the framework was applied show that the proposed framework can be effectively utilized by electric power distribution companies to increase the resilience of their systems.

关键词： Angular deflection Cost–benefit analysis Finite element analysis Pole damage Utility system resilience Wind-related disaster

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Assessing quality of volunteer crowdsourcing contributions:lessons from the Cropland Capture game

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International Journal of Digital Earth 2016年第4期9卷 410-426页

作者： Carl F.Salk Tobias Sturn Linda See Steffen Fritz Christoph Perger Ecosystems Services and management program International Institute for Applied Systems AnalysisLaxenburgAustria Southern Swedish Forest Research Center Swedish University of Agricultural SciencesAlnarpSweden

Volunteered geographic information(VGI)is the assembly of spatial information based on public *** VGI has proliferated in recent years,assessing the quality of volunteer-contributed data has proven challenging,leading some to question the efficiency of such *** this paper,we compare several quality metrics for individual volunteers’*** data were the product of the‘Cropland Capture’game,in which several thousand volunteers assessed 165,000 images for the presence of cropland over the course of 6 *** compared agreement between volunteer ratings and an image’s majority classification with volunteer self-agreement on repeated images and expert *** also examined the impact of experience and learning on *** self-agreement was nearly always higher than agreement with majority classifications,and much greater than agreement with expert validations although these metrics were all positively *** quality showed a broad trend toward improvement with experience,but the highest accuracies were achieved by a handful of moderately active contributors,not the most active *** results emphasize the importance of a universal set of expert-validated tasks as a gold standard for evaluating VGI quality.

关键词： crowdsourcing volunteered geographic information cropland data quality image classification Geo-Wiki

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Numerical modeling of earthen dam breach due to piping failure

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Water Science and Engineering 2019年第3期12卷 169-178页

作者： Sheng-shui Chen Qi-ming Zhong Guang-ze Shen Department of Geotechnical Engineering Nanjing Hydraulic Research Institute Nanjing 210024 China Key Laboratory of failure Mechanism and Safety Control Techniques of Earth-rock Dam of the Ministry of Water Resources Nanjing 210029 China Department of Dam Safety management Nanjing Hydraulic Research Institute Nanjing 210029 China

Based on model tests of earthen dam breach due to piping failure, a numerical model was developed.A key difference from previous research is the assumption that the cross-section of the pipe channel is an arch, with a rectangle at the bottom and a semicircle at the top before the collapse of the pipe roof, rather than a rectangular or circular cross-section.A shear stress-based erosion rate formula was utilized, and the arched pipe tunnel was assumed to enlarge along its length and width until the overlying soil could no longer maintain *** flow and open channel flow were adopted to calculate the breach flow discharge for pressure and free surface flows, *** collapse of the pipe roof was determined by comparing the weight of the overlying soil and the cohesion of the soil on the two sidewalls of the *** the collapse, overtopping failure dominated, and the limit equilibrium method was adopted to estimate the stability of the breach slope when the water flow *** addition, incomplete and base erosion, as well as one-and two-sided breaches were taken into *** USDAARS-HERU model test P1, with detailed measured data, was used as a case study, and two artificially filled earthen dam failure cases were studied to verify the *** analysis demonstrates that the proposed model can provide satisfactory results for modeling the breach flow discharge and breach development *** analysis shows that the soil erodibility and initial piping position significantly affect the prediction of the breach flow ***, a comparison with a well-known numerical model shows that the proposed model performs better than the NWS BREACH model.

关键词： Earthen dam Piping failure Overtopping failure Breach flow Numerical modeling Sensitivity analysis

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What factors explain anger and mental health during the COVID-19 pandemic? The case of Israeli society

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World Journal of Psychiatry 2021年第10期11卷 864-875页

作者： Orna Braun-Lewensohn Sarah Abu-Kaf Tehila Kalagy Department of Interdisciplinary Studies Conflict Management&Resolution ProgramBen-Gurion University of the NegevBeer Sheva 8410501IsraelIsrael Department of Public Policy and management Ben-Gurion University of the NegevBeer Sheva 8410501IsraelIsrael

BACKGROUND What factors affected the levels of anger and emotional distress experienced during the coronavirus disease 2019(COVID-19)pandemic?We hypothesized that(1)sociodemographic factors and resiliency factors would partially explain psychological distress and anger,with stronger resiliency associated with lower levels of distress and anger;(2)women would report more trust in national leadership,as well as more psychological problems;(3)individuals of low socioeconomic status would report less resiliency,less trust in national leadership,and greater distress than individuals of higher socioeconomic status;and(4)hope would mediate the relationships between the other resiliency factors and both anger and *** To explore whether community resilience,hope,and trust in leaders were associated with lower levels of anger and emotional distress during the COVID-19 *** For this observational study,data were gathered in Israel during the second wave of the COVID-19 pandemic,just before the Jewish New Year(mid-September 2020),as a second lockdown was *** were gathered from 636 Israeli adults,who were recruited by the Midgam research *** participants filled out self-reported questionnaires including one on state anger,the Brief Symptom Inventory as a measure of mental-health problems(i.e.,somatization,depression,and anxiety),and questionnaires about trust in the state’s leaders,community resilience(CCRAM),and hope as measures of coping resources and resiliency.t-tests were used to explore differences between men and women and between those of lower and higher socioeconomic status.A hierarchical multiple regression analysis was then used to examine whether and how the sociodemographic and resiliency variables explained state anger and psychological distress.A Sobel test was used to evaluate the possible effects of hope on community resilience and trust in leadership in the context of both distress and *** Our results revealed di

关键词： Community resilience Hope Trust in government Anger Mental health Pandemic

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China's Energy Consumption Forecasting by GMDH Based Auto-Regressive Model

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Journal of Systems Science & Complexity 2017年第6期30卷 1332-1349页

作者： XIE Ling XIAO Jin HU Yi ZHAO Hengjun XIAO Yi Business School Sichuan University School of Economics and management University of Chinese Academy of Sciences School of Economics and management Sichuan Radio and TV University School of Information management Central China Normal University

It is very significant for us to predict future energy consumption accurately. As for China's energy consumption annual time series, the sample size is relatively small. This paper combines the traditional auto-regressive model with group method of data handling(GMDH) suitable for small sample prediction, and proposes a novel GMDH based auto-regressive(GAR) model. This model can finish the modeling process in self-organized manner, including finding the optimal complexity model, determining the optimal auto-regressive order and estimating model parameters. Further, four different external criteria are proposed and the corresponding four GAR models are constructed. The authors conduct empirical analysis on three energy consumption time series, including the total energy consumption, the total petroleum consumption and the total gas consumption. The results show that AS-GAR model has the best forecasting performance among the four GAR models, and it outperforms ARIMA model, BP neural network model, support vector regression model and GM(1, 1) ***, the authors give the out of sample prediction of China's energy consumption from 2014 to 2020 by AS-GAR model.

关键词： Auto-regressive model energy demand prediction GMDH small sample forecasting

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Multi-frequency formation mechanism and modulation strategy of self-priming enhanced submerged pulsed waterjet

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International Journal of Mining Science and Technology 2025年第2期35卷 175-189页

作者： Haojie Jia Yanwei Liu Weiqin Zuo Hongkai Han Ping Chang Mohammad Waqar Ali Asad Guozhong Hu Jian Miao Hani SMitri College of Safety Science and Engineering Henan Polytechnic UniversityJiaozuo 454003China Henan International Joint Laboratory of Coal Mine Safety and Occupational Hazards Prevention and Control Jiaozuo 454003China Zhengzhou Institute for Advanced Research of Henan Polytechnic University Zhengzhou 451464China WA School of Mines:Minerals Energy and Chemical EngineeringCurtin UniversityKalgoorlie WA 6430Australia School of Mines China University of Mining and TechnologyXuzhou 221116China School of Intelligent Engineering Shandong Management UniversityJinan 250357China Department of Mining and Materials Engineering McGill UniversityMontreal H3A0E8Canada

Under submerged conditions, compared with traditional self-excited oscillating pulsed waterjets(SOPWs), annular fluid-enhanced self-excited oscillating pulsed waterjets(AFESOPWs) exhibit a higher surge pressure through self-priming. However, their pressure frequency and cavitation characteristics remain unclear, resulting in an inability to fully utilize resonance and cavitation erosion to break coal and rock. In this study, high-frequency pressure testing, high-speed photography, and large eddy simulation(LES) are used to investigate the distribution of the pressure frequency band, evolution law of the cavitation cloud, and its regulation mechanism of a continuous waterjet, SOPW, and AFESOPW. The results indicated that the excitation of the plunger pump, shearing layer vortex, and bubble collapse corresponded to the three high-amplitude frequency bands of the waterjet pressure. AFESOPWs have an additional self-priming frequency that can produce a larger amplitude under a synergistic effect with the second high-amplitude frequency band. A better cavitation effect was produced after self-priming the annulus fluid, and the shedding frequency of the cavitation clouds of the three types of waterjets was linearly related to the cavitation number. The peak pressure of the waterjet and cavitation erosion effect can be improved by modulating the waterjet pressure oscillation frequency and cavitation shedding frequency.

关键词： Multi-frequency Modulation self-priming Submerged waterjet Cavitation

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Regeneration of the heart:f rom molecular mechanisms to clinical therapeutics

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Military Medical Research 2024年第1期11卷 80-97页

作者： Qian-Yun Guo Jia-Qi Yang Xun-Xun Feng Yu-Jie Zhou Beijing Key Laboratory of Precision Medicine of Coronary Atherosclerotic Disease Beijing Institute of Heart Lung and Blood Vessel DiseaseClinical Center for Coronary Heart DiseaseDepartment of CardiologyBeijing Anzhen HospitalCapital Medical UniversityBeijing 100029China

heart injury such as myocardial infarction leads to cardiomyocyte loss,fibrotic tissue deposition,and scar *** changes reduce cardiac contractility,resulting in heart failure,which causes a huge public health *** personnel,compared with civilians,is exposed to more stress,a risk factor for heart diseases,making cardiovascular health management and treatment innovation an important topic for military *** far,medical intervention can slow down cardiovascular disease progression,but not yet induce heart *** the past decades,studies have focused on mechanisms underlying the regenerative capability of the heart and applicable approaches to reverse heart *** have emerged from studies in animal models and early clinical *** interventions show the potential to reduce scar formation and enhance cardiomyocyte proliferation that counteracts the pathogenesis of heart *** this review,we discuss the signaling events controlling the regeneration of heart tissue and summarize current therapeutic approaches to promote heart regeneration after injury.

关键词： heart regeneration Cardiac disease Therapeutics Signaling mechanisms

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