Design and optimization of fluid lubricated bearings operated with extreme working performances——a comprehensive review

Fluid lubricated bearings have been widely adopted as support components for high-end equipment in metrology,semiconductor devices,aviation,strategic defense,ultraprecision manufacturing,medical treatment,and power generation.In all these applications,the equipment must deliver extreme working performances such as ultraprecise movement,ultrahigh rotation speed,ultraheavy bearing loads,ultrahigh environmental temperatures,strong radiation resistance,and high vacuum operation,which have challenged the design and optimization of reliable fluid lubricated bearings.Breakthrough of any related bottlenecks will promote the development course of high-end equipment.To promote the advancement of high-end equipment,this paper reviews the design and optimization of fluid lubricated bearings operated at typical extreme working performances,targeting the realization of extreme working performances,current challenges and solutions,underlying deficiencies,and promising developmental directions.This paper can guide the selection of suitable fluid lubricated bearings and optimize their structures to meet their required working performances.

Determinants of Satisfaction at Work and Its Reflections on Performance

This study examines the relationship between job satisfaction and performance,investigating personality traits and satisfaction aspects among employees of a Federal Higher Education Institution.A questionnaire was administered to 658 participants,using structural equation modeling for analysis.Results highlighted that challenging work,neuroticism,and self-esteem significantly influenced overall workplace satisfaction,while general satisfaction,self-efficacy,and lack of attention were key determinants of work performance.This emphasizes the importance for managers to prioritize factors enhancing employee satisfaction,as it positively correlates with job performance.

Experimental study on the working performance of different milling tools for multistage fracturing ball seats

To achieve the secondary production in multistage fracturing wells of tight oil,milling tools are usually used to remove the multistage fracturing ball seats to achieve production with a large diameter in later.In this paper,first of all,the working mechanism of milling tools for multistage fracturing ball seats was studied and a mechanical analysis model of single abrasive grain was established.Then,an experimental system for milling tools was developed,and the experimental tests of the flat,the blade,and the slope milling tool were conducted in order.Besides,the morphology of chips and the surface morphology of the workpiece after the experiment were analyzed.Also,the working performance of milling tools was evaluated from the perspectives of working safety,working efficiency,and wear resistance of the milling tool.The results show that the torque of the milling tool increases nonlinearly with the increase in the cutting depth of the abrasive grain and increases linearly with the increase in the cutting width.Also,the chips are irregular particles and the size is mainly from 10 to 50μm.So,the chips should be pumped up with a small pump pressure and a large displacement.Besides this,the cutting depths of the abrasive grains are from 216.20 to 635.47μm and the bottom surface of the milling tool should be eccentric to avoid the zero point of cutting speed.Furthermore,the torque of the slope milling tool is 23.8%larger than that of the flat milling tool,which is also 30.4%smaller than that of the blade milling tool.Compared with the flat milling tool,the working efficiency of the blade milling tool improves by 79.9%and the slope milling tool improves by 111.1%.Also,the wear resistance of the blade milling tool decreases by 102.7%,while the slope milling tool declines by 32.6%when compared with the flat milling tool.Therefore,the slope milling tool has the characteristics of moderate torque,stable working conditions,the highest working efficiency,and fine wear resistance,which is preferably used to mill multistage fracturing ball seats.This study provides a theoretical basis and guidance for milling multistage fracturing ball seats on-site and realizing production with a large diameter in later stages of multistage fracturing wells.

Work-related quality of life and performance appraisal among nurses at a tertiary hospital in Philippines

Objective:The objective of the study is to describe the work-related quality of life(WRQOL)among nurses and explore its association with performance evaluation ratings.Methods:A cross-sectional design was utilized measuring the WRQOL scale and the previous performance appraisal rating.Multistage sampling approach was utilized with nurses stratified based on their position and then systematically random sampled based on their unit assignment.Results:One hundred and eighty-two nurses were included.About half reported a high quality of work life(101;55.5%).Low scores were noted on the subscale working conditions(100;54.9%),low to average responses for home-work interface(109;59.9%),control at work(100;54.9%),and stress at work(90;49.5%).A higher proportion of nurses reported positive responses toward the areas of general well-being(113;62.1%)and job-career satisfaction(112;61.5%),than in the other subscales.There were notable differences between WRQOL ratings:(1)Head nurses had the highest perceived quality of work life,followed by nurse supervisors and charge nurses(F=6.1,P<0.01)and(2)Nurses in the pay-patient services reported lower quality of working life,while those in office and outpatient services had more positive scores(F=4.6,P<0.01).Conclusion:Only more than half of the nurses reported a high quality of work life,some of its dimensions,particularly job and career satisfaction and working conditions,appeared to vary in the perceived degree across years in service,work hours,and position.The assessment of the quality of work life may serve as an important tool to address staff burnout,absenteeism and other issues that affect job performance among health-care professionals.

Effect of Collective Bargaining on Employee Motivation in the Zimbabwean Gold Mining Sector

The purpose of this study is to determine the effect of collective bargaining on employee motivation in the Zimbabwean gold mining sector.The continued restless among employees at various gold mines in the midlands province has resulted in productivity levels dwindling.There has been increased labour turnover by employees as well as increased union representation to management.Questionnaire were used to collect data.In this article a population of one thousand employees was used.A sample of two hundred employees was selected across the board.The results of the study indicate positive relationships between collective bargaining and job satisfaction among the employees in the Zimbabwean gold mining sector.Implications of these results are that the human resource interventions are required in order to create an environment in which employees can freely engage in collective bargaining.Furthermore,the results indicate that collective bargaining engenders intrinsic motivation and above all allows for the protection of employee’s rights and welfare as well as promoting industrial democracy.This study recommends that managers should guard against preventing or obstructing employees from seeking legal redress to protect their interest.In addition,labour officers should be given the right of reasonable access to workers during working hours at their organisations for the purposes of advising the workers on the law.The employees should be given a latitude to belong to a trade union and or workers committee.

心理契约对基层全科医师工作绩效的影响机制:离职倾向的中介调节作用

目的 分析心理契约对基层全科医师工作绩效的影响机制,探析离职倾向在其中的中介调节作用,为基层全科医师队伍建设提供依据。方法 采用问卷调查对南京市浦口区基层医疗卫生机构的全科医师进行调研,收集其社会人口学信息,测量其心理契约、工作绩效和离职倾向水平,拟合多重线性回归模型分析作用机制和中介调节效应,验证本研究的4个研究假设。结果 基层全科医师心理契约对工作绩效存在正向促进作用(b=0.554,P<0.001)。纳入离职倾向后,心理契约和队伍稳定性对于工作绩效均存在正向促进作用(b=0.285、0.357,P<0.001)。纳入心理契约和离职倾向的交互项后,交互项的偏回归系数差异具有统计学意义(b=-0.013,P=0.006),说明低离职倾向抑制了心理契约提升工作绩效的正向作用。结论 应重视基层全科医师内在情感(即心理契约)的激励作用,采用多举措降低离职意愿,提升职业认同,避免发生“出工不出力”现象,促进工作绩效提升和基层全科医师队伍稳定。

临床护理人员组织承诺水平及影响因素分析

目的 了解临床护理人员组织承诺及各维度水平,分析其影响因素,为进一步提高员工组织认同感、工作满意度、工作绩效等提供参考依据。方法 2019年11月,对上海市某区区属医疗机构的临床护理人员进行问卷调查。主要内容包括组织承诺量表的五大维度:情感承诺、规范承诺、理想承诺、经济承诺、机会承诺。使用Kruskal-Wallis H或Mann-Whitney U检验对不同特征的临床护理人员组织承诺量表各维度得分进行差异分析,采用两水平方差成分模型分析影响临床护理人员组织承诺的因素。结果 临床护理人员的组织承诺总得分M(P_(25),P_(75))为63.0(56.0,70.0)分,与其各维度均处于较高水平。相对而言,机会承诺得分相对较低,得分M(P_(25),P_(75))为11.0(9.0,13.0)分;二级综合医院临床护理人员的组织承诺水平相对较低;临床护理人员组织承诺水平随收入水平的增长逐渐提高;较年轻的临床护理人员组织承诺水平相对较低。结论 二级综合医院可以结合自身优势和医疗服务需求,找准发展方向。同时,应注重执业环境的改善,加强医院文化建设;仍需加强护理人力资源队伍建设,重视对临床护理人员的后期培养。同时,关注较年轻的临床护理人员,帮助增强其岗位胜任力,降低其心理压力,进一步加强其组织归属感。另外,临床护理人员的收入问题也应得到重点关注,需加大对护理人力资源的投入,并完善其绩效考核制度。

Integrated Control Model for Time and Cost Risk in Project Management

Time, cost and quality are the three main targets to be controled in project management. However, the control and management of time and cost risk are usually carried out respectively, which will bring such problems as the delay of schedule by reason of the impracticability of cash flow, the money difficulties caused by delay of schedule and so on. In order to control and manage the time and cost risk effectively and simultaneously, a time & cost risk control model based on schedule programme was established with the use of the quantitativemodels of BCWS, BCWP and ACWP in this paper. Subsequently, the analysis of variance for the whole project and the single activity was introduced on the basis of BCWS, BCWP and ACWP so that the project can be controlled and managed effectively. Furthermore, an example given behind in detail expressly illustrated that the model set up above was practicableto project management. However, the method of optimizing the cash flow based on time and cost risk to obtain BCWS should be considered properlyand carefully with respect to the different circumstances of the project, and an efficient and adequate interval report system should be set up on the site of the project.

An integrative review of the influence of job strain and coping on nurses'work performance:Understanding the gaps in oncology nursing research

Nursing is known to be a stressful profession that can lead to physical and psychological health issues and behavioural problems.In oncology,workload among nurses is believed to be increasing in conjunction with rapidly increasing numbers of patients with cancer and staff shortages worldwide,therefore it is essential to sustain a quality oncology nurse workforce.Numerous studies have presented evidence on job strain,effects of coping strategies,and nurses'work performance within healthcare settings,but few have focused on oncology settings and none of these on nurses working in Saudi Arabia.The purpose of this review was to summarize empirical and theoretical evidence concerning job-related stressors in nurses,particularly oncology nurses,and the interrelationships among job strain,coping strategies,and work performance in this population.Search strategies identified studies published on studies in peer-reviewed journals from 2004 to 2016.Twenty-five nursing studies were found examining the relationships among the concepts of interest.Common job-related stressors among oncology nurses were high job demands,dealing with death/dying,lack of job control,and interpersonal conflicts at work.Job strain was found to be significantly linked to coping strategies,and negatively associated with work performance among nurses in general.There is no existing empirical evidence to support the relationship between coping strategies and work performance among oncology nurses.The present evidence is limited,and a considerable amount of research is required in the future to expand the oncology nursing literature.Research is needed to investigate job-related stressors and their effects on oncology nurses.

Association of post-traumatic stress disorder and work performance: A survey from an emergency medical service, Karachi, Pakistan

BACKGROUND: The purpose of the study was to explore the association between posttraumatic stress disorder(PTSD) and work performance of emergency medical services personnel in Karachi, Pakistan.METHODS: Emergency medical service personnel were screened for potential PTSD using Impact of Event Scale-Revised(IES-R). Work performance was assessed on the basis of fi ve variables: number of late arrivals to work, number of days absent, number of days sick, adherence to protocol, and patient satisfaction over a period of 3 months. In order to model outcomes like the number of late arrivals to work, days absent and days late, negative binomial regression was applied, whereas logistic regression was applied for adherence to protocol and linear for patient satisfaction scores.RESULTS: Mean scores of PTSD were 24.0±12.2. No association was found between PTSD and work performance measures: number of late arrivals to work(RRadj 0.99; 0.98–1.00), days absent(RRadj 0.98; 0.96–0.99), days sick(RRadj 0.99; 0.98–1.00), adherence to protocol(ORadj 1.01; 0.99–1.04) and patient satisfaction(β 0.001%–0.03%) after adjusting for years of formal schooling, living status, coping mechanism, social support, working hours, years of experience and anxiety or depression.CONCLUSION: No statistically significant association was found between PTSD and work performance amongst EMS personnel in Karachi, Pakistan.

Solar Shutters based on Photovoltaic Power Generation

This paper introduces a set of electrical energy-saving system for commercial office buildings,aiming at making better use of solar energy and photovoltaic power generation.Solar energy is a renewable energy source,which is inexhaustible clean energy and has great commercial application value.Based on this fact,we plan to design a unique and novel solar shutter in combination with the daily observation and the shape of solar panels.The shutter blades are equipped with an automatic light tracking system,and the angle of the blades can be adjusted in time through photoresistor induction,that is,as much solar energy as possible can be converted into electric energy for load use,and at the same time,comfortable light can be provided for the house.In essence,the system is a small photovoltaic power generation system,which runs all day with high-efficiency based on automatic sun tracking.Among them,the basic operation route includes:solar position detection,computer data processing,photovoltaic and electric volt energy conversion,circuit connection,etc.From the current debugging results,the shutter has the characteristics of humanization,high efficiency,cleanliness and so on.Through this energy-saving system,we hope to maximize the use of solar energy in the premise of low cost,so as to achieve the purpose of energy saving.

Mediating effect of work engagement between job characteristics and nursing performance among general hospital nurses

Objective:This study aimed to determine the effects of job characteristics and work engagement on the nursing performance of nurses working in general hospitals.Methods:Data were collected from 169 nurses who are working in a general hospital in South Korea by using a cross-sectional descriptive survey design.Results:Nurses’job characteristics and work engagement showed positive effects on nursing performance.This effect was magnified when work engagement was used as a mediating variable.Conclusions:The findings elucidate the factors influencing job performance and provide managers with important information for developing programs to improve the job skills and work engagement of nurses.

Perceived Indoor Discomfort, Performance and Productivity

Even all indoor environmental standards are met the users are usually not satisfied and perceived discomfort is occurred in the smart office buildings. The most frequently cause of discomfort in smart buildings is overrun of intelligence. There are physical and psychological factors that influenced building users＇ comfort. An indoor air quality seems to be one of the main problems of smart office buildings. In Slovakia the office buildings relating to indoor environment European standard are mostly evaluated as the non-low polluting buildings. The pollution from building as well as the pollution from occupancy and using was respected. The odor intensity and indoor air acceptability were assessed by a sensory panel. The concentrations of total volatile organic compounds and carbon dioxide were measured. The odors from building materials studied under different air change rate are presented in this paper. The case study of indoor air acceptability concerning to indoor odors under occupancy and its affect on perceived air quality influenced by air change rate are also presented in this paper.

Application of Snapback Chronometry Method in Calculation of Regulation

Work study is an area of construction production rationalization in which with scientific, logical, holistic and system analysis methods of the process we gain optimum in way of work and time of work. Chronometry method is one of the work study methods which is appropriate for recording shorter cyclic processes and is based on statistical sampling theory. Determination of cyclic times and work performances of standard cyclic construction machines （SCCM） is one of key assumptions of dynamic planning of machine work on every construction site. Calculation methods of SCCM work performances arc one of basic research objects in the field of construction organization and technology. Study shows applied chronometry method in work of standard cyclic construction machine. Goal of this study is to accomplish regulation through measured time cycle and compare measured effects with effects obtained with standard methodology of calculating hydraulic excavator practical achievement for gaining regulation in order to determine main reasons which effect work performance on site.

Is ＂Happy Worker＂ More Productive

The hypothesis ＂happy productive worker＂ states that happy employees, whose needs are satisfied in their workplace, have greater performance than unhappy employees. Therefore, the purpose of this research is to examine empirically the effects that job satisfaction and well-being at work generate on the individual job performance, investigating the moderating role that the components of the organizational structure play in this relationship. To achieve the main objective, some secondary objectives were proposed： （1） test the predictive effect of well-being, satisfaction, personal, and professional variables on individual performance; and （2） test the moderating effect of the components of the organizational structure in the relationship among well-being, satisfaction, and individual job performance. This research originates of a consolidated statement for the business society, but very few empirical studies. This way, the hypothesis consisted in the components of the organizational structure will positively enhance the relationship among well-being at work, job satisfaction, and individual job performance. The final sample consisted of 134 participants, of a clinical laboratory and of federal court of justice. For the development of the questionnaire, four instruments were used; one for each construct. The proposal has four relationship variables and the statistical procedure used to test this hypothesis was multiple linear regressions. Considering the hypothetical theoretical model presented, personal and professional variables are predictors of job performance; thus, these variables were also included as independent variables. The results of the regression model showed that the variables ＂age＂, ＂well-being at work＂, ＂job satisfaction＂, and ＂components of organizational structure＂ are responsible for explaining 64% of the variance of the variable criteria and individual job performance The moderating role of the variable ＂components of organizational structure＂ was also observed, because its inclusion increased the explained variance of the dependent variable. After all the discussions developed, the two main contributions appear： （1） the predictive effect of well-being at work in relation to performance and （2） identifying the moderating effect of the components of the organizational structure.

Thermochemical non-equilibrium flow characteristics of high Mach number inlet in a wide operation range

The high-temperature non-equilibrium effect is a novel and significant issue in the flows over a high Mach number(above Mach 8)air-breathing vehicle.Thus,this study attempts to investigate the high-temperature non-equilibrium flows of a curved compression two-dimensional scramjet inlet at Mach 8 to 12 utilizing the two-dimensional non-equilibrium RANS calculations.Notably,the thermochemical non-equilibrium gas model can predict the actual high-temperature flows,and the numerical results of the other four thermochemical gas models are only used for comparative analysis.Firstly,the thermochemical non-equilibrium flow fields and work performance of the inlet at Mach 8 to 12 are analyzed.Then,the influences of high-temperature non-equilibrium effects on the starting characteristics of the inlet are investigated.The results reveal that a large separation bubble caused by the cowl shock/lower wall boundary layer interaction appears upstream of the shoulder,at Mach 8.The separation zone size is smaller,and its location is closer to the downstream area while the thermal process changes from frozen to non-equilibrium and then to equilibrium.With the increase of inflow Mach number,the thermochemical non-equilibrium effects in the whole inlet flow field gradually strengthen,so their influences on the overall work performance of the high Mach number inlet are more obvious.The vibrational relaxation or thermal non-equilibrium effects can yield more visible influences on the inlet performance than the chemical non-equilibrium reactions.The inlet in the thermochemical non-equilibrium flow can restart more easily than that in the thermochemical frozen flow.This work should provide a basis for the design and starting ability prediction of the high Mach number inlet in the wide operation range.

The effects of portable cooling systems on thermal comfort and work performance in a hot environment

There are some special spaces in which there is no air conditioning or the people are in move,thus exposing people to a hot environment.In this study,portable cooling systems were proposed and their effects on thermal comfort and work performance were investigated at an air temperature of 32°C.Four conditions were established:cool air towards breathing zone(A),chest and back cooling(B)#combined cooling(C)and no cooling(D).Twenty-eight subjects were exposed to the four conditions in a counterbalanced order.During each exposure they performed tasks and made subjective assessments,while multiple physiological parameters were measured.Compared with no cooling(D),cool air towards breathing zone(A)and chest and back cooling(B)improved work performance by 17.5%and 19.25%,respectively,while decreased the subjects'thermal sensation,skin temperature,and heart rate.When the two cooling systems were combined(C),larger improvements in thermal comfort and work performance were achieved than no cooling(D);the mean thermal sensation rating decreased from 2.4 to 0.7;work performance increased by up to 33%,and physiological parameters including skin temperature,pulse,heart rate and salivary alpha-amylase significantly decreased.The present results suggest that the proposed portable cooling systems could maintain thermal comfort and work performance in a hot environment,while potentially improve air quality for some special spaces.

High performance work systems and corporate performance： the influence of entrepreneurial orientation and organizational learning

This study investigates the functioning mechanisms of how high performance work systems （HPWS） affect organizational performance. We propose that （HPWS） can positively affect organizational performance through the mediating role of entrepreneurial orientation. An organization with high performance work systems can perform better if it enjoys high level of organizational learning. We design and administer a survey questionnaire to high-level executives or founders of companies from manufacturing and service industries and receive 176 valid responses. The results of the empirical data indicate that the relationship between high performance work systems and corporate performance is more positive when organizational learning is stronger. Entrepreneurial orientation partially mediates the relationship between high performance work systems and organizational performance. This study opens new research avenues by extending and incorporating explanations and predictions of HPWS and entrepreneurial orientation, two areas that largely have been considered independently of each other. Implications for practice and directions for future research are provided.

High Performance Work Systems and Employee Creativity： The Mediating Effect of Knowledge Sharing

Employee creativity is both the core element of a firm＇s innovation capabilities and the sources for its growth. To improve an organization＇s ability to innovate, it is necessary to improve the creativity of its employees. Based on theories from strategic human resource management, creativity and organizational learning, this paper investigates the relationship between high performance work systems and employee creativity and explores the role knowledge sharing plays in their relationship. A questionnaire is designed and administered to a group of part-time executive students in the winter of 2012. Two hundred students are invited to answer the survey questions with 117 valid responses. Data are collected and processed by using statistical regressions. The empirical findings reveal that high performance work systems positively affect knowledge sharing and employee creativity. Knowledge sharing plays a mediating role in the relationship between high performance work systems and employee creativity. Implications for practice and future research are discussed.

Development of unilateral obstacle-avoiding mower for Y-trellis pear orchard

To solve the problem of weeding under Y-trellis pear orchards,a unilateral obstacle-avoiding mower(UOAM)was developed in this study.The mower is composed of an obstacle-avoiding disc mechanism,a hydraulic profiling mechanism,and a cutting disc mechanism.The diameter of the obstacle-avoiding disc was 0.7 m,which could swing around the trunk or ground pile actuated by the spring mechanism.The piston movement of the hydraulic cylinder controls the working position of the obstacle-avoiding disc.The maximum extension distance of the hydraulic profiling arm was 1 m.Based on the national standards and actual situation of orchards,the optimum parameters were determined with a combination of advancing speed of 0.44 m/s,rotation speed of the cutting disc at 2000 r/min,blade number of 2,and cutting edge length of 0.2 m.Finally,the design parameters were verified by the mathematical model of the blade cutting edge trajectory and multi-body dynamics simulation.Taking stubble cutting stability,leakage rate,working efficiency and costs as the test indexes,field performance comparison tests were carried out on the three operation modes of UOAM mowing,shoulder carrying mower(SCM)mowing and manual weeding.Test results showed that the coefficient variation of stubble cutting height of UOAM was the smallest,showing that the working stability of UOAM was better than the other two treatments.The leakage rate of UOAM was 2.42%,and its coefficient variation was lower than that of SCM.The working efficiency of UOAM was much higher than that of SCM and manual weeding,which was 4.44 times of SCM and 20 times of manual weeding.The profitable area of UOAM was 7.02 hm^(2),showing that it was suitable for large-scale mechanized Y-trellis pear orchards.