In this paper,an efficien formulation based on the Lagrangian method is presented to investigate the contact–impact problems of f exible multi-body systems.Generally,the penalty method and the Hertz contact law are t...In this paper,an efficien formulation based on the Lagrangian method is presented to investigate the contact–impact problems of f exible multi-body systems.Generally,the penalty method and the Hertz contact law are the most commonly used methods in engineering applications.However,these methods are highly dependent on various non-physical parameters,which have great effects on the simulation results.Moreover,a tremendous number of degrees of freedom in the contact–impact problems will influenc thenumericalefficien ysignificantl.Withtheconsideration of these two problems,a formulation combining the component mode synthesis method and the Lagrangian method is presented to investigate the contact–impact problems in fl xible multi-body system numerically.Meanwhile,the finit element meshing laws of the contact bodies will be studied preliminarily.A numerical example with experimental verificatio will certify the reliability of the presented formulationincontact–impactanalysis.Furthermore,aseries of numerical investigations explain how great the influenc of the finit element meshing has on the simulation results.Finally the limitations of the element size in different regions are summarized to satisfy both the accuracy and efficien y.展开更多
Database applications are becoming increasingly popular, mainly due to the advanced data management facilities that the underlying database management system offers compared against traditional legacy software applica...Database applications are becoming increasingly popular, mainly due to the advanced data management facilities that the underlying database management system offers compared against traditional legacy software applications. The interaction, however, of such applications with the database system introduces a number of issues, among which, this paper addresses the impact analysis of the changes performed at the database schema level. Our motivation is to provide the software engineers of database applications with automated methods that facilitate major maintenance tasks, such as source code corrections and regression testing, which should be triggered by the occurrence of such changes. The presented impact analysis is thus two-folded： the impact is analysed in terms of both the affected source code statements and the affected test suites concerning the testing of these applications. To achieve the former objective, a program slicing technique is employed, which is based on an extended version of the program dependency graph. The latter objective requires the analysis of test suites generated for database applications, which is accomplished by employing testing techniques tailored for this type of applications. Utilising both the slicing and the testing techniques enhances program comprehension of database applications, while also supporting the development of a number of practical metrics regarding their maintainability against schema changes. To evaluate the feasibility and effectiveness of the presented techniques and metrics, a software tool, called DATA, has been implemented. The experimental results from its usage on the TPC-C case study are reported and analysed.展开更多
Based on linearized 2-D Navier-Stokes equation, a Laplacetransform-boundary element coupling method for viscousfluid-structure impact analysis is proposed. Under assumption ofincompressibility for the fluid, the corre...Based on linearized 2-D Navier-Stokes equation, a Laplacetransform-boundary element coupling method for viscousfluid-structure impact analysis is proposed. Under assumption ofincompressibility for the fluid, the corresponding equivalentboundary integral equation in terms of the potential function andstream function is first established by Lamb's transform in theLaplace transform domain.展开更多
Huge amount of digital data of the Great East Japan Earthquake is provided by the highly-developed digital data technology. But the method and technique for analysis of these huge digital data are not developed suffic...Huge amount of digital data of the Great East Japan Earthquake is provided by the highly-developed digital data technology. But the method and technique for analysis of these huge digital data are not developed sufficiently. This paper proposes a running spectrum technique for text data and analyzing changes of disaster phase during the disaster management cycle. Impact analysis of the nuclear power plant accidents have been performed by using Fukushima Minpo newspaper for its verification. The result shows the dynamic characteristics of the nuclear power plant accidents. As the time interval B becomes longer, the analysis data is used from wide range period along with the smoothing effect. When observing different time intervals B, fewer keywords have been ranked in the longer time intervals of B. The proposed technique is a powerful tool to effective and efficient disaster response and management. analyze effectively the huge amount of digital data for the展开更多
Numerical climate models render data in a gridded format which is often problematic for integrated analysis with other kinds of data in jurisdictional formats. In this paper a joint analysis of municipal Gross Domesti...Numerical climate models render data in a gridded format which is often problematic for integrated analysis with other kinds of data in jurisdictional formats. In this paper a joint analysis of municipal Gross Domestic Product per capita (GDPc) and predicted temperature increase was undertaken in order to estimate different levels of human and economic exposure. This is based on a method of converting model outputs into a country municipal grid which enabled depicting climate predictions from the Eta-Hadgem2-ES Regional Climate Model (RCM) into the municipal level in Brazil. The conversion to country municipality grid was made using a combination of interpolation and buffering techniques in ArcGIS for two emission scenarios (RCP 4.5 and 8.5) and three timeframes (2011-2040, 2041-2070, 2071-2100) for mean temperature increase and number of heatwave days (WSDI). The results were used to support the Third National Communication (TCN) of Brazil to the United Nations Framework Convention on Climate Change (UNFCCC) and show a coherent matching of the gridded output from the original RCM. The joint climate and GDPc analysis show that in the beginning of the century the more severe warming is centred over regions where GDPc is generally higher (Centre-West and Southeast). At the end of the century, critical levels of warming spread north and northeastwards where municipalities have the lowest GDPc levels. In the high emission scenario (RCP 8.5), the strongest warming and the spreading over poorer regions are anticipated to the mid-century. These results are the key to further explore solutions for climate change adaptation based on current resources and prepare in different sectors, for long-term risk management and climate adaptation planning strategies.展开更多
BACKGROUND Myocardial infarction,particularly ST-segment elevation myocardial infarction(STEMI),is a key global mortality cause.Our study investigated predictors of mortality in 96 STEMI patients undergoing primary pe...BACKGROUND Myocardial infarction,particularly ST-segment elevation myocardial infarction(STEMI),is a key global mortality cause.Our study investigated predictors of mortality in 96 STEMI patients undergoing primary percutaneous coronary intervention at Erbil Cardiac Center.Multiple factors were identified influencing in-hospital mortality.Significantly,time from symptom onset to hospital arrival emerged as a decisive factor.Consequently,our study hypothesis is:"Reducing time from symptom onset to hospital arrival significantly improves STEMI prognosis."AIM To determine the key factors influencing mortality rates in STEMI patients.METHODS We studied 96 consecutive STEMI patients undergoing primary percutaneous coronary intervention(PPCI)at the Erbil Cardiac Center.Their clinical histories were compiled,and coronary evaluations were performed via angiography on admission.Data included comorbid conditions,onset of cardiogenic shock,complications during PPCI,and more.Post-discharge,one-month follow-up assessments were completed.Statistical significance was set at P<0.05.RESULTS Our results unearthed several significant findings.The in-hospital and 30-d mortality rates among the 96 STEMI patients were 11.2%and 2.3%respectively.On the investigation of independent predictors of in-hospital mortality,we identified atypical presentation,onset of cardiogenic shock,presence of chronic kidney disease,Thrombolysis In Myocardial Infarction grades 0/1/2,triple vessel disease,ventricular tachycardia/ventricular fibrillation,coronary dissection,and the no-reflow phenomenon.Specifically,the recorded average time from symptom onset to hospital arrival amongst patients who did not survive was significantly longer(6.92±3.86 h)compared to those who survived(3.61±1.67 h),P<0.001.These findings underscore the critical role of timely intervention in improving the survival outcomes of STEMI patients.CONCLUSION Our results affirm that early hospital arrival after symptom onset significantly improves survival rates in STEMI patients,highlighting the critical need for prompt intervention.展开更多
Using linear regression and correlation analysis method,the variation trend characteristics of average temperature,sunshine,precipitation and the phenology of five kinds of animals(Barn Swallows,Frogs,Cryptotympana at...Using linear regression and correlation analysis method,the variation trend characteristics of average temperature,sunshine,precipitation and the phenology of five kinds of animals(Barn Swallows,Frogs,Cryptotympana atra,Crickets,Indian Cuckoo) in Huimin County during 1980-2008 were analyzed.On this basis,the relationship between the phenological phases of various animals and monthly temperature,sunshine and precipitation was analyzed.And the reasons that the phenological phases of various animals adapted to the climatic factors were also discussed.展开更多
This paper presents a transient energy based screening approach for quickly identifying potential critical attacks that might have significant impacts on power system transient stability.Specifically,the proposed appr...This paper presents a transient energy based screening approach for quickly identifying potential critical attacks that might have significant impacts on power system transient stability.Specifically,the proposed approach focuses on the total transient energy injected into power systems as the result of assumptive cyber attacks.The computational improvements of the proposed method are significant as the time-domain simulations can be avoided.The efficacy of the proposed approach is demonstrated using a practical power system with various cyber attack scenarios.The identification results of the proposed method can be used to guide more detailed impact analysis and to develop more effective countermeasures against cyber attacks.展开更多
The multi-material assembled light alloy wheel presents an effective lightweight solution for new energy vehicles,but its riveting connection remains a problem.To address this problem,this paper proposed the explicit ...The multi-material assembled light alloy wheel presents an effective lightweight solution for new energy vehicles,but its riveting connection remains a problem.To address this problem,this paper proposed the explicit riveting-implicit springback-implicit fatigue/explicit impact sequence coupling simulation analysis method,analyzed the fatigue and impact performance of the punching riveting connected magnesium/aluminum alloy(Mg/Al)assembled wheel,and constructed some major evaluation indicators.The accuracy of the proposed simulation method was verified by conducting physical experiments of single and cross lap joints.The punching riveting process parameters of the assembled wheel joints were defined as design variables,and the fatigue and impact performance of the assembled wheel was defined as the optimization objective.The connection-performance integration multi-objective optimization design of the assembled wheel considering riveting residual stress was designed via Taguchi experiment,grey relational analysis,analytic hierarchy process,principal component analysis,and entropy weighting methods.The optimization results of the three weighting methods were compared,and the optimal combination of design variables was determined.The fatigue and impact performance of the Mg/Al assembled wheel were effectively improved after optimization.展开更多
[Objective] The research aimed to study the influence of facility agriculture development on the climate variation in Weifang. [Method] Shouguang was selected as the representative station of greenhouse shed planting ...[Objective] The research aimed to study the influence of facility agriculture development on the climate variation in Weifang. [Method] Shouguang was selected as the representative station of greenhouse shed planting zone. By using the precipitation, temperature and relative humidity, etc. in Weifang City during 1961-2010, the climatic variation situations in the whole city and the greenhouse shed planting zone were analyzed. The variation trend and evolution characteristics of climate in the different seasons before and after the facility agriculture plantation were contrasted and analyzed. [Result] The annual rainfall and relative humidity presented the declining trend in the whole city in recent 50 years. The annual average, maximum and minimum temperatures all presented the rising trend. Since the large-scale plantation of greenhouse shed, the declining range of annual rainfall in the greenhouse shed planting zone was lower than that in the whole city, and the declining range of relative humidity was obviously higher than that in the whole city. The rising ranges of annual average, maximum and minimum temperatures were higher than that in the whole city. [Conclusion] The research provided the theory basis for the development of facility agriculture.展开更多
Objective To evaluate the predictive value and impact for the index of microcirculatory resistance(IMR)in myocardial infarction(MI)patients with elective percutaneous coronary intervention(PCI)for treating coronary ar...Objective To evaluate the predictive value and impact for the index of microcirculatory resistance(IMR)in myocardial infarction(MI)patients with elective percutaneous coronary intervention(PCI)for treating coronary artery occlusion.Methods A total of 34 patients with STEMI or non-STEMI treated after 12h time window展开更多
Arctic shipping poses environmental risks due to the region’s fragile ecosystems and rapid climate changes.Effective risk assessment tools are needed to ensure sustainable expansion and to carry out environmental imp...Arctic shipping poses environmental risks due to the region’s fragile ecosystems and rapid climate changes.Effective risk assessment tools are needed to ensure sustainable expansion and to carry out environmental impact assessments.This paper explores applications of Failure Modes and Effects Analysis(FMEA)and Systems-Theoretic Process Analysis(STPA)coupled with the consequences of a“Dynamic baseline approach”for Arctic shipping environmental impact assessment.Shipping entails complex interactions between environmental,technical,human,and organizational factors.FMEA identifies failure modes and their effects through component-level analysis.STPA examines how unsafe control actions can emerge from interactions between system components.Combining these techniques with a dynamic(variable)baseline,accounting for inherent ongoing changing Arctic conditions,offers a robust methodology.A qualitative case study shows that prioritizing hazards by risk,yields highest concerns,as increased greenhouse gas emissions,black carbon deposition on ice and snow,and response delays to accidents represent some of the most important identified threats to the environment.The use of FMEA and STPA are complementary,and differences are highlighted.The methodology applied,should be representative for the qualitative risk analysis methodology,and while the findings are impacted by the perspectives of the authors,the process followed is intended to identify and rank risks in a consistent manner.Mitigations measures must be in place to target these issues.Constant monitoring of the changing ecological and socioeconomic Arctic baselines supports the responses.This methodology offers a starting point for systematically addressing environmental impact risks in the data-limited Arctic.Integrating failure modes and effect analysis,system theories and dynamic baselines,account for identification of the complex interactions,influencing environmental risks in this rapidly evolving region.展开更多
The method,in which a few carats of diamond grits are placed inside a capsule together with a steel ball,shaken for a number of times,and the unbroken ratio of the grits is then used to evaluate the quality of the dia...The method,in which a few carats of diamond grits are placed inside a capsule together with a steel ball,shaken for a number of times,and the unbroken ratio of the grits is then used to evaluate the quality of the diamond,has been well established for many years.However,the unbroken percentage,in an equivalent view,represents the impact toughness of the grits and cannot reflect the value of the crushing energy.Most of the previous empirical formulas obtained from experiments by scholars cannot be applied to practical tests.In this paper,a dimensional analysis was applied to investigate the impact toughness experiment,and the dimensionless relationship has been built among those variables such as the toughness index,the impact time,the impact frequency and the crushing energy per unit area.According to the results of a large number of experiments with synthetic diamond grits of mesh size 45/50,the percentage of the broken grits H is proportional to the impact time T^（1.14） when the impact frequency is 2400 r/min,and the impact frequency f^（2.576） when the number of impacts is 2000.展开更多
There is a common difficulty in elastic-plastic impact codes such as EPIC[2,3] NONSAP[4], etc.. Most of these codes use the simple linear functions usually taken from static problem to represent the displacement compo...There is a common difficulty in elastic-plastic impact codes such as EPIC[2,3] NONSAP[4], etc.. Most of these codes use the simple linear functions usually taken from static problem to represent the displacement components. In such finite element formulation, the stress components are constant in each element and they are discontinuous in any two neighboring elements. Therefore, the bases of using the virtual work principle in such elements are unreliable. In this paper, we introduce a new method, namely, the compatible stress iterative method, to eliminate the above-said difficulty. The calculated examples show that the calculation using the new method in dynamic finite element analysis of high velocity impact is valid and stable, and the element stiffness can be somewhat reduced.展开更多
1.This study is one of The Applied Economic Institutes Linkages Project(AERIL)which is funded by theCanadian International Development Agency(CIDA)and jiontly managed by The Conference Board of Canada(CBOC)and the Int...1.This study is one of The Applied Economic Institutes Linkages Project(AERIL)which is funded by theCanadian International Development Agency(CIDA)and jiontly managed by The Conference Board of Canada(CBOC)and the International Trade Research Institute in China.It is jointly implemented by the Institute ofEconomic Research of the Chinese State Planning Commission and the North—South Institute of Canada。展开更多
The tropical cyclone that lands or passes through Guangxi coast is a serious natural disaster, which brings about strong winds, heavy rains, storm surges and other disasters causing severe damage of property or casual...The tropical cyclone that lands or passes through Guangxi coast is a serious natural disaster, which brings about strong winds, heavy rains, storm surges and other disasters causing severe damage of property or casualties in the coastal region every year. By counting and analyzing the tropical cyclones affecting Guangxi coast from 1950 to 2012, we find that the annual number of tropical cyclones changes significantly, and the maximum value can be up to 9, whereas the minimum value is 0 in some year. The regularity of seasonal distribution of tropical cyclones is obvious, and the peak period is in July, August and September every year, followed by June and October. Most of tropical cyclones come from the east of Philippines. After entering the South China Sea and passing through Hainan province and Leizhou Peninsula, they landed on Guangxi coast once again and caused the mean of peak surge reaching 111.2 cm, which is 2.6 times of non-landing typhoon. The formation of storm surge disaster is directly related to the severe typhoon weather systems, diurnal spring tide and discharge of river flood. Severe typhoons generate huge waves and rainfall, which lead to the rise of water level at the estuary, and would result in significant increasing water when stacking up with the storm surge, and cause huge tidal disaster.展开更多
Agricultural and rural economic policy system is one main driving force for the evolvement of agricultural Non-Point Source （NPS） pollution. In this paper, the main policies that influence agricultural NPS pollution...Agricultural and rural economic policy system is one main driving force for the evolvement of agricultural Non-Point Source （NPS） pollution. In this paper, the main policies that influence agricultural NPS pollution are chosen, and a method to evaluate the impacts of agricultural and rural economic policy system on agricultural NPS pollution is brought forward. According to this, the questions about how and to what degree the policy system influence on agricultural NPS pollution are discussed.展开更多
The calculation results show that relative cut-in depth at the moment of maximum shearing force decreases with the increase of steel plate thickness; along with blade clearance increasing, shearing force would increas...The calculation results show that relative cut-in depth at the moment of maximum shearing force decreases with the increase of steel plate thickness; along with blade clearance increasing, shearing force would increase slightly compared with the slide pressure of blade carrier; shearing force increases significantly with the increasing blunt end radius; shearing force displays a bit decrement with the decreasing platen force, while the pressure on slide plate of blade carrier increases substantially; shearing force increases a bit with the increasing shear velocity and decreases when nip angle increases while the horizontal component force of shearing force along the direction of plate width increases rapidly. The above results have important reference and actual using value for studying calculation of mechanical parameters of rolling shear and its structural design.展开更多
High-density aluminum foam can provide higher stiffness and absorb more energy during the impact Obtaining the constitutive law of such foam requires tri-axial tests with very high pressure,where difficulty may arise ...High-density aluminum foam can provide higher stiffness and absorb more energy during the impact Obtaining the constitutive law of such foam requires tri-axial tests with very high pressure,where difficulty may arise because the hydrostatic pressure can reach more than 30 MPa.In this paper,instead of using tri-axial tests,we proposed three easier tests-tension,compression and shear to obtain the parameters of constitutive model(the Deshpande-Fleck model).To verify the constitutive model both statically and dynamically,we carried out addi-tional triaxial tests and direct impact tests,respectively.Based on the derived model,we performed finite element simulation to study the impact response of the present foam.By dimensional analysis,we proposed an empirical equation for a non-dimensional impact time the impact time divided by the time required for plastic wave travelling from the impact surface to the bottom surface,to det ermine the deformation charac teristic of the aluminum foam after impact.For the case with t_(d)≤1,the deformation tends to exhibit a shock-type characteristic,while for the case with t_(d)>5,the deformation tends to exhibit an upsetting-type characteristic.展开更多
This paper investigates the application of Direct Current Atmospheric Plasma Spraying(DC-APS)as a versatile thermal spray technique for the application of coatings with tailored properties to various substrates.The pr...This paper investigates the application of Direct Current Atmospheric Plasma Spraying(DC-APS)as a versatile thermal spray technique for the application of coatings with tailored properties to various substrates.The process uses a high-speed,high-temperature plasma jet to melt and propel the feedstock powder particles,making it particularly useful for improving the performance and durability of components in renewable energy systems such as solar cells,wind turbines,and fuel cells.The integration of nanostructured alumina(Al_(2)O_(3))thin films into multilayer coatings is considered a promising advancement that improves mechanical strength,thermal stability,and environmental resistance.The study highlights the importance of understanding injection parameters and their impact on coating properties and uses simulation tools such as the Jets&Poudres(JP)code for in-depth analysis.Furthermore,the paper discusses the implementation of Artificial Neural Networks(ANN)to optimize the coating process by predicting flight characteristics and improving operating conditions.The results show that ANN models are effective in achieving highly accurate prediction values,highlighting the potential of AI in improving thermal spray technology.展开更多
基金supported by the National Science Foundation of China (Grants 11132007,11272203)
文摘In this paper,an efficien formulation based on the Lagrangian method is presented to investigate the contact–impact problems of f exible multi-body systems.Generally,the penalty method and the Hertz contact law are the most commonly used methods in engineering applications.However,these methods are highly dependent on various non-physical parameters,which have great effects on the simulation results.Moreover,a tremendous number of degrees of freedom in the contact–impact problems will influenc thenumericalefficien ysignificantl.Withtheconsideration of these two problems,a formulation combining the component mode synthesis method and the Lagrangian method is presented to investigate the contact–impact problems in fl xible multi-body system numerically.Meanwhile,the finit element meshing laws of the contact bodies will be studied preliminarily.A numerical example with experimental verificatio will certify the reliability of the presented formulationincontact–impactanalysis.Furthermore,aseries of numerical investigations explain how great the influenc of the finit element meshing has on the simulation results.Finally the limitations of the element size in different regions are summarized to satisfy both the accuracy and efficien y.
文摘Database applications are becoming increasingly popular, mainly due to the advanced data management facilities that the underlying database management system offers compared against traditional legacy software applications. The interaction, however, of such applications with the database system introduces a number of issues, among which, this paper addresses the impact analysis of the changes performed at the database schema level. Our motivation is to provide the software engineers of database applications with automated methods that facilitate major maintenance tasks, such as source code corrections and regression testing, which should be triggered by the occurrence of such changes. The presented impact analysis is thus two-folded： the impact is analysed in terms of both the affected source code statements and the affected test suites concerning the testing of these applications. To achieve the former objective, a program slicing technique is employed, which is based on an extended version of the program dependency graph. The latter objective requires the analysis of test suites generated for database applications, which is accomplished by employing testing techniques tailored for this type of applications. Utilising both the slicing and the testing techniques enhances program comprehension of database applications, while also supporting the development of a number of practical metrics regarding their maintainability against schema changes. To evaluate the feasibility and effectiveness of the presented techniques and metrics, a software tool, called DATA, has been implemented. The experimental results from its usage on the TPC-C case study are reported and analysed.
基金the National Defence Foundation of Science & Technology of China (No.J14.8.1.JW0515)
文摘Based on linearized 2-D Navier-Stokes equation, a Laplacetransform-boundary element coupling method for viscousfluid-structure impact analysis is proposed. Under assumption ofincompressibility for the fluid, the corresponding equivalentboundary integral equation in terms of the potential function andstream function is first established by Lamb's transform in theLaplace transform domain.
文摘Huge amount of digital data of the Great East Japan Earthquake is provided by the highly-developed digital data technology. But the method and technique for analysis of these huge digital data are not developed sufficiently. This paper proposes a running spectrum technique for text data and analyzing changes of disaster phase during the disaster management cycle. Impact analysis of the nuclear power plant accidents have been performed by using Fukushima Minpo newspaper for its verification. The result shows the dynamic characteristics of the nuclear power plant accidents. As the time interval B becomes longer, the analysis data is used from wide range period along with the smoothing effect. When observing different time intervals B, fewer keywords have been ranked in the longer time intervals of B. The proposed technique is a powerful tool to effective and efficient disaster response and management. analyze effectively the huge amount of digital data for the
基金the United Nations Programme for Development(UNDP),Rede Clima(FINEP 01.13.0353.00)the Brazilian Ministry for Science and Technology for their financial support
文摘Numerical climate models render data in a gridded format which is often problematic for integrated analysis with other kinds of data in jurisdictional formats. In this paper a joint analysis of municipal Gross Domestic Product per capita (GDPc) and predicted temperature increase was undertaken in order to estimate different levels of human and economic exposure. This is based on a method of converting model outputs into a country municipal grid which enabled depicting climate predictions from the Eta-Hadgem2-ES Regional Climate Model (RCM) into the municipal level in Brazil. The conversion to country municipality grid was made using a combination of interpolation and buffering techniques in ArcGIS for two emission scenarios (RCP 4.5 and 8.5) and three timeframes (2011-2040, 2041-2070, 2071-2100) for mean temperature increase and number of heatwave days (WSDI). The results were used to support the Third National Communication (TCN) of Brazil to the United Nations Framework Convention on Climate Change (UNFCCC) and show a coherent matching of the gridded output from the original RCM. The joint climate and GDPc analysis show that in the beginning of the century the more severe warming is centred over regions where GDPc is generally higher (Centre-West and Southeast). At the end of the century, critical levels of warming spread north and northeastwards where municipalities have the lowest GDPc levels. In the high emission scenario (RCP 8.5), the strongest warming and the spreading over poorer regions are anticipated to the mid-century. These results are the key to further explore solutions for climate change adaptation based on current resources and prepare in different sectors, for long-term risk management and climate adaptation planning strategies.
文摘BACKGROUND Myocardial infarction,particularly ST-segment elevation myocardial infarction(STEMI),is a key global mortality cause.Our study investigated predictors of mortality in 96 STEMI patients undergoing primary percutaneous coronary intervention at Erbil Cardiac Center.Multiple factors were identified influencing in-hospital mortality.Significantly,time from symptom onset to hospital arrival emerged as a decisive factor.Consequently,our study hypothesis is:"Reducing time from symptom onset to hospital arrival significantly improves STEMI prognosis."AIM To determine the key factors influencing mortality rates in STEMI patients.METHODS We studied 96 consecutive STEMI patients undergoing primary percutaneous coronary intervention(PPCI)at the Erbil Cardiac Center.Their clinical histories were compiled,and coronary evaluations were performed via angiography on admission.Data included comorbid conditions,onset of cardiogenic shock,complications during PPCI,and more.Post-discharge,one-month follow-up assessments were completed.Statistical significance was set at P<0.05.RESULTS Our results unearthed several significant findings.The in-hospital and 30-d mortality rates among the 96 STEMI patients were 11.2%and 2.3%respectively.On the investigation of independent predictors of in-hospital mortality,we identified atypical presentation,onset of cardiogenic shock,presence of chronic kidney disease,Thrombolysis In Myocardial Infarction grades 0/1/2,triple vessel disease,ventricular tachycardia/ventricular fibrillation,coronary dissection,and the no-reflow phenomenon.Specifically,the recorded average time from symptom onset to hospital arrival amongst patients who did not survive was significantly longer(6.92±3.86 h)compared to those who survived(3.61±1.67 h),P<0.001.These findings underscore the critical role of timely intervention in improving the survival outcomes of STEMI patients.CONCLUSION Our results affirm that early hospital arrival after symptom onset significantly improves survival rates in STEMI patients,highlighting the critical need for prompt intervention.
文摘Using linear regression and correlation analysis method,the variation trend characteristics of average temperature,sunshine,precipitation and the phenology of five kinds of animals(Barn Swallows,Frogs,Cryptotympana atra,Crickets,Indian Cuckoo) in Huimin County during 1980-2008 were analyzed.On this basis,the relationship between the phenological phases of various animals and monthly temperature,sunshine and precipitation was analyzed.And the reasons that the phenological phases of various animals adapted to the climatic factors were also discussed.
基金supported in part by the National Science Foundation under Grant ECCS-0955265.
文摘This paper presents a transient energy based screening approach for quickly identifying potential critical attacks that might have significant impacts on power system transient stability.Specifically,the proposed approach focuses on the total transient energy injected into power systems as the result of assumptive cyber attacks.The computational improvements of the proposed method are significant as the time-domain simulations can be avoided.The efficacy of the proposed approach is demonstrated using a practical power system with various cyber attack scenarios.The identification results of the proposed method can be used to guide more detailed impact analysis and to develop more effective countermeasures against cyber attacks.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51975244 and 51475201).The authors would like to express their appreciations for the fund supports.
文摘The multi-material assembled light alloy wheel presents an effective lightweight solution for new energy vehicles,but its riveting connection remains a problem.To address this problem,this paper proposed the explicit riveting-implicit springback-implicit fatigue/explicit impact sequence coupling simulation analysis method,analyzed the fatigue and impact performance of the punching riveting connected magnesium/aluminum alloy(Mg/Al)assembled wheel,and constructed some major evaluation indicators.The accuracy of the proposed simulation method was verified by conducting physical experiments of single and cross lap joints.The punching riveting process parameters of the assembled wheel joints were defined as design variables,and the fatigue and impact performance of the assembled wheel was defined as the optimization objective.The connection-performance integration multi-objective optimization design of the assembled wheel considering riveting residual stress was designed via Taguchi experiment,grey relational analysis,analytic hierarchy process,principal component analysis,and entropy weighting methods.The optimization results of the three weighting methods were compared,and the optimal combination of design variables was determined.The fatigue and impact performance of the Mg/Al assembled wheel were effectively improved after optimization.
文摘[Objective] The research aimed to study the influence of facility agriculture development on the climate variation in Weifang. [Method] Shouguang was selected as the representative station of greenhouse shed planting zone. By using the precipitation, temperature and relative humidity, etc. in Weifang City during 1961-2010, the climatic variation situations in the whole city and the greenhouse shed planting zone were analyzed. The variation trend and evolution characteristics of climate in the different seasons before and after the facility agriculture plantation were contrasted and analyzed. [Result] The annual rainfall and relative humidity presented the declining trend in the whole city in recent 50 years. The annual average, maximum and minimum temperatures all presented the rising trend. Since the large-scale plantation of greenhouse shed, the declining range of annual rainfall in the greenhouse shed planting zone was lower than that in the whole city, and the declining range of relative humidity was obviously higher than that in the whole city. The rising ranges of annual average, maximum and minimum temperatures were higher than that in the whole city. [Conclusion] The research provided the theory basis for the development of facility agriculture.
文摘Objective To evaluate the predictive value and impact for the index of microcirculatory resistance(IMR)in myocardial infarction(MI)patients with elective percutaneous coronary intervention(PCI)for treating coronary artery occlusion.Methods A total of 34 patients with STEMI or non-STEMI treated after 12h time window
基金supported in parts by funds provided by“The Program for Maritim Competence(MARKOM II),”(https://www.markomii.no/om-markomii/),project 10039funds made available to UIT,The Arctic University of Norway。
文摘Arctic shipping poses environmental risks due to the region’s fragile ecosystems and rapid climate changes.Effective risk assessment tools are needed to ensure sustainable expansion and to carry out environmental impact assessments.This paper explores applications of Failure Modes and Effects Analysis(FMEA)and Systems-Theoretic Process Analysis(STPA)coupled with the consequences of a“Dynamic baseline approach”for Arctic shipping environmental impact assessment.Shipping entails complex interactions between environmental,technical,human,and organizational factors.FMEA identifies failure modes and their effects through component-level analysis.STPA examines how unsafe control actions can emerge from interactions between system components.Combining these techniques with a dynamic(variable)baseline,accounting for inherent ongoing changing Arctic conditions,offers a robust methodology.A qualitative case study shows that prioritizing hazards by risk,yields highest concerns,as increased greenhouse gas emissions,black carbon deposition on ice and snow,and response delays to accidents represent some of the most important identified threats to the environment.The use of FMEA and STPA are complementary,and differences are highlighted.The methodology applied,should be representative for the qualitative risk analysis methodology,and while the findings are impacted by the perspectives of the authors,the process followed is intended to identify and rank risks in a consistent manner.Mitigations measures must be in place to target these issues.Constant monitoring of the changing ecological and socioeconomic Arctic baselines supports the responses.This methodology offers a starting point for systematically addressing environmental impact risks in the data-limited Arctic.Integrating failure modes and effect analysis,system theories and dynamic baselines,account for identification of the complex interactions,influencing environmental risks in this rapidly evolving region.
基金Supported by the National Natural Science Foundation of China(11572047)
文摘The method,in which a few carats of diamond grits are placed inside a capsule together with a steel ball,shaken for a number of times,and the unbroken ratio of the grits is then used to evaluate the quality of the diamond,has been well established for many years.However,the unbroken percentage,in an equivalent view,represents the impact toughness of the grits and cannot reflect the value of the crushing energy.Most of the previous empirical formulas obtained from experiments by scholars cannot be applied to practical tests.In this paper,a dimensional analysis was applied to investigate the impact toughness experiment,and the dimensionless relationship has been built among those variables such as the toughness index,the impact time,the impact frequency and the crushing energy per unit area.According to the results of a large number of experiments with synthetic diamond grits of mesh size 45/50,the percentage of the broken grits H is proportional to the impact time T^（1.14） when the impact frequency is 2400 r/min,and the impact frequency f^（2.576） when the number of impacts is 2000.
文摘There is a common difficulty in elastic-plastic impact codes such as EPIC[2,3] NONSAP[4], etc.. Most of these codes use the simple linear functions usually taken from static problem to represent the displacement components. In such finite element formulation, the stress components are constant in each element and they are discontinuous in any two neighboring elements. Therefore, the bases of using the virtual work principle in such elements are unreliable. In this paper, we introduce a new method, namely, the compatible stress iterative method, to eliminate the above-said difficulty. The calculated examples show that the calculation using the new method in dynamic finite element analysis of high velocity impact is valid and stable, and the element stiffness can be somewhat reduced.
文摘1.This study is one of The Applied Economic Institutes Linkages Project(AERIL)which is funded by theCanadian International Development Agency(CIDA)and jiontly managed by The Conference Board of Canada(CBOC)and the International Trade Research Institute in China.It is jointly implemented by the Institute ofEconomic Research of the Chinese State Planning Commission and the North—South Institute of Canada。
基金supported by National Nature Science (Grant No. 41266002)
文摘The tropical cyclone that lands or passes through Guangxi coast is a serious natural disaster, which brings about strong winds, heavy rains, storm surges and other disasters causing severe damage of property or casualties in the coastal region every year. By counting and analyzing the tropical cyclones affecting Guangxi coast from 1950 to 2012, we find that the annual number of tropical cyclones changes significantly, and the maximum value can be up to 9, whereas the minimum value is 0 in some year. The regularity of seasonal distribution of tropical cyclones is obvious, and the peak period is in July, August and September every year, followed by June and October. Most of tropical cyclones come from the east of Philippines. After entering the South China Sea and passing through Hainan province and Leizhou Peninsula, they landed on Guangxi coast once again and caused the mean of peak surge reaching 111.2 cm, which is 2.6 times of non-landing typhoon. The formation of storm surge disaster is directly related to the severe typhoon weather systems, diurnal spring tide and discharge of river flood. Severe typhoons generate huge waves and rainfall, which lead to the rise of water level at the estuary, and would result in significant increasing water when stacking up with the storm surge, and cause huge tidal disaster.
文摘Agricultural and rural economic policy system is one main driving force for the evolvement of agricultural Non-Point Source （NPS） pollution. In this paper, the main policies that influence agricultural NPS pollution are chosen, and a method to evaluate the impacts of agricultural and rural economic policy system on agricultural NPS pollution is brought forward. According to this, the questions about how and to what degree the policy system influence on agricultural NPS pollution are discussed.
基金Item Sponsored by National Natural Science Foundation of China(50954003)New-Century Talents Support Plan of China(NECT-05-0268)Provincial Natural Science Foundation of Shanxi Province of China(2010011036-2)
文摘The calculation results show that relative cut-in depth at the moment of maximum shearing force decreases with the increase of steel plate thickness; along with blade clearance increasing, shearing force would increase slightly compared with the slide pressure of blade carrier; shearing force increases significantly with the increasing blunt end radius; shearing force displays a bit decrement with the decreasing platen force, while the pressure on slide plate of blade carrier increases substantially; shearing force increases a bit with the increasing shear velocity and decreases when nip angle increases while the horizontal component force of shearing force along the direction of plate width increases rapidly. The above results have important reference and actual using value for studying calculation of mechanical parameters of rolling shear and its structural design.
基金This work was supported by the National Natural Science Foundation of China(11772334,11890681)the Youth Innovation Promotion Association CAS(2018022)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB22040501).
文摘High-density aluminum foam can provide higher stiffness and absorb more energy during the impact Obtaining the constitutive law of such foam requires tri-axial tests with very high pressure,where difficulty may arise because the hydrostatic pressure can reach more than 30 MPa.In this paper,instead of using tri-axial tests,we proposed three easier tests-tension,compression and shear to obtain the parameters of constitutive model(the Deshpande-Fleck model).To verify the constitutive model both statically and dynamically,we carried out addi-tional triaxial tests and direct impact tests,respectively.Based on the derived model,we performed finite element simulation to study the impact response of the present foam.By dimensional analysis,we proposed an empirical equation for a non-dimensional impact time the impact time divided by the time required for plastic wave travelling from the impact surface to the bottom surface,to det ermine the deformation charac teristic of the aluminum foam after impact.For the case with t_(d)≤1,the deformation tends to exhibit a shock-type characteristic,while for the case with t_(d)>5,the deformation tends to exhibit an upsetting-type characteristic.
文摘This paper investigates the application of Direct Current Atmospheric Plasma Spraying(DC-APS)as a versatile thermal spray technique for the application of coatings with tailored properties to various substrates.The process uses a high-speed,high-temperature plasma jet to melt and propel the feedstock powder particles,making it particularly useful for improving the performance and durability of components in renewable energy systems such as solar cells,wind turbines,and fuel cells.The integration of nanostructured alumina(Al_(2)O_(3))thin films into multilayer coatings is considered a promising advancement that improves mechanical strength,thermal stability,and environmental resistance.The study highlights the importance of understanding injection parameters and their impact on coating properties and uses simulation tools such as the Jets&Poudres(JP)code for in-depth analysis.Furthermore,the paper discusses the implementation of Artificial Neural Networks(ANN)to optimize the coating process by predicting flight characteristics and improving operating conditions.The results show that ANN models are effective in achieving highly accurate prediction values,highlighting the potential of AI in improving thermal spray technology.
