An efficient formulation based on the Lagrangian method for contact–impact analysis of flexible multi-body system

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.

A Two-folded Impact Analysis of Schema Changes on Database Applications

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.

LAPLACE TRANSFORM-BOUNDARY ELEMENT COUPLING METHOD FOR VISCOUS FLUIDSTRUCTURE IMPACT ANALYSIS

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.

Municipal Temperature and Heatwave Predictions as a Tool for Integrated Socio-Environmental Impact Analysis in Brazil

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.

Impact of primary percutaneous coronary intervention on ST-segment elevation myocardial infarction patients:A comprehensive analysis

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.

Fast Screening Severe Cyber Attacks via Transient Energy-based Impact Analysis

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.

Analysis on the Impact of Facility Agriculture Development on Climate Change in Weifang

[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.

Fatigue and impact analysis and multi-objective optimization design of Mg/Al assembled wheel considering riveting residual stress

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.

Predictive value and impact analysis for the index of microcirculatory resistance in MI patients with elective percutaneous coronary intervention

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

A Study of the Impact of Personality and Social Psychology on Mental Health

With the continuous development and progress of economy,people's living standard and culture level have been improved,but with it,there are also various kinds of life stress,study stress and work stress,which make people's mental health problems in life more andmore prominent,and how to improve students'mental health level is the main task of each education stage.The current psychology discipline system has been perfected,including personality psychology and social psychology,which are effectively applied in the actual mental health education or psychological guidance work,and are key disciplines to improve people's mental health.The theoretical system of personality and social psychology consists of three theories:the theory of planned behavior,the theory of explanatory levels,and the theory of self-determination,all of which have an irreplaceable influence on mental health.In this regard,this paper combines relevant literature and work experience to study in depth the influence of personality ansocial psychology on mental health.

Dimensional analysis of the impact toughness test for synthetic diamond grits

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.

THE APPLICATION OF COMPATIBLE STRESS ITERATIVE METHOD IN DYNAMIC FINITE ELEMENT ANALYSIS OF HIGH VELOCITY IMPACT

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.

Policy Towards Gender Equality in Employment in a Globalizing Economy——An outline of the analysis report on the impacts of China's economic reform on women employment

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。

Citation analysis of the scientific publications of Britton Chance in ISI citation indexes

Britton Chance was a pioneer in many scientifc fields such as enzymatic reaction kinetis,bioenergetics,metabolism,in vivo NMr,and biophotonics.As an engineer,physical chemist,physicist,physiologist,biophysicist,biochemist,innovator and educator,he had worked indiversifed fields over extended periods bet ween 1926 until his death in 2010,at the age of 97.Inorder to illustrate his scientific career and great impact on research from a new perspective,weemploy scientometric analysis tools to analyze the publications of Britton Chance with datadownloaded from the ISI Citation Indexes in April 2013.We included articles,reviews andproceding papers but excluded meeting abstracts.In total,we obtained 1023 publication recordswith 1236 authors in 266 joumals with 17,114 citations from 1945 to 2013.We show the annualpublications and citations that Britton Chance received from 1945 to 2013,and generate HistCitemaps on the basis of the global citations(GCS)and local(sel)citations(LCS)to show thecitation relationships among the top-30 publications of Britton Chance.Metabolism and the development of physical methods to probe it appear to be the commecting thread of the lifelongresearch of Britton Chance.Furthermore,we generate the joumal map and co-authorship maptoshow the broad scope of research topics and collaborators and the high impacts of the scientificoeuvre of Britton Chance ranging from physics,engineering,chemistry and biology to medicine.

气候变化对动物物候的影响分析(英文)

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.

海岛居民慢性病现状及影响因素分析

目的研究海岛居民人群健康状况、慢性病现状和影响因素。方法采用分层随机抽样方法,抽取5个村,共600户,2130人,按统一设计的调查表对被调查户所有成员逐一询问。资料整理后,用EPIdata建立数据库,录入计算机,采用SPSS12.0软件包进行统计分析。结果海岛居民总慢性病患病率为35.16%,女性高于男性。患病率随着年龄的增加而增高,农业生产者和不识字者最高。危害海岛居民前五位的病种为慢性胃肠炎、椎间盘疾病、痛风、慢性支气管炎和咽喉扁桃气管炎。心血管和肿瘤已成为威胁海岛居民健康的潜在疾病。结论快速建立全方位的农村社区卫生服务,加大推广农村新型医疗保险制度,重组海岛卫生资源。

RMT-Based Urban Traffic Cross-Correlation Analysis and Its Application on Traffic Incident Impact Analyses

Cross-correlating traffic flow data at different intersections in an urban transportation network is important for understanding the collective behavior of constituents in a complex system and for predicting the risk of network-wide congestion. In this work, a Random Matrix Theory （RMT） based method is used to describe the collective behavior from massive traffic data sets. Nonrandom correlations between traffic flow series recorded in the Beijing road network occur both with and without detrending. The effect of the traffic load on the correlation patterns of network-wide traffic flows is analyzed using the RMT analysis of a simulated data set collected from Paramics. The RMT analysis is also used to evaluate the impact of incidents on the network-wide traffic status. Cluster analysis is used to find the largest cluster in the network which indicates the critical congestion caused by the incident. All the results show that RMT analyses are an effective method for investigating systematic interactions in urban transportation systems.

Influence of Climatic Conditions on Planting of Hami Melon

Climate warming has made the planting area of Hami melon expand northward to Barry Bakai Town,Altay City,near 47° N. Climate events often induce the occurrence of pests and diseases in crops,affecting the steady production of Hami melon. In 2013,pests and diseases occurred seriously,resulting in low yield and poor quality of Hami melon. Based on the production survey data of Hami melon in recent20 years,the interaction of various meteorological factors in different time and different intervals of various factors was analyzed in this paper to explore the characteristics of the meteorological factors that cause diseases and influence the quality of Hami melon.

Real-time prediction of projectile penetration to laminates by training machine learning models with finite element solver as the trainer

Studies on ballistic penetration to laminates is complicated,but important for design effective protection of structures.Experimental means of study is expensive and can often be dangerous.Numerical simulation has been an excellent supplement,but the computation is time-consuming.Main aim of this thesis was to develop and test an effective tool for real-time prediction of projectile penetrations to laminates by training a neural network and a decision tree regression model.A large number of finite element models were developed;the residual velocities of projectiles from finite element simulations were used as the target data and processed to produce sufficient number of training samples.Study focused on steel 4340tpolyurea laminates with various configurations.Four different 3D shapes of the projectiles were modeled and used in the training.The trained neural network and decision tree model was tested using independently generated test samples using finite element models.The predicted projectile velocity values using the trained machine learning models are then compared with the finite element simulation to verify the effectiveness of the models.Additionally,both models were trained using a published experimental data of projectile impacts to predict residual velocity of projectiles for the unseen samples.Performance of both the models was evaluated and compared.Models trained with Finite element simulation data samples were found capable to give more accurate predication,compared to the models trained with experimental data,because finite element modeling can generate much larger training set,and thus finite element solvers can serve as an excellent teacher.This study also showed that neural network model performs better with small experimental dataset compared to decision tree regression model.

Applied Energy

https://www.sciencedirect.com/journal/applied-energy/vol/263/suppl/C Volume 263,1 April 2020(1)Application of simultaneous thermoelectric cooling and heating to improve the performance of a solar still:An experimental study and exergy analysis,by Shahin Shoeibi,Nader Rahbar,Ahad Abedini Esfahlani,Hadi Kargarsharifabad.