Automotive-grade Complementary Metal-Oxide-Semiconductor(CMOS)sensors play a crucial role in automotive electronic systems,especially in the context of the rapid development of Advanced Driver Assistance Systems(ADAS)...Automotive-grade Complementary Metal-Oxide-Semiconductor(CMOS)sensors play a crucial role in automotive electronic systems,especially in the context of the rapid development of Advanced Driver Assistance Systems(ADAS)and autonomous driving technologies.Their performance is directly related to the safety and reliability of vehicles.However,automobiles will face a variety of complex environmental conditions during the actual operation,such as high temperature,low temperature,vibration,humidity changes,and light changes,which may have an impact on the performance of CMOS sensors.Therefore,it is of great significance to study the performance of automotive-grade CMOS sensors in different environments.展开更多
To realize automatic control of automobile transmission performance test stand Methods The automatic control technique of the lubricant temperature,the program- controll- edautomaticshifting of the transmission,the c...To realize automatic control of automobile transmission performance test stand Methods The automatic control technique of the lubricant temperature,the program- controll- edautomaticshifting of the transmission,the continuous adjusting of revolution speed and load, data-acquisition and data real-time processing were adopted.Results The lubricant temperature was controlled at the set temperature ±2℃.The automatic shifting of the trans- mission is simple,reliable and accurate.The automatic adjusting of load and rotation speed is rapidandaccurate,the torque divergence is ±1N·m,the rotation speed divergence is ±5r/min Conclusion The four kinds of techniques are applied into the automobile transmission perfor- mance test stand successfully. mancetest stand successfully.展开更多
In view of the limitations of solid metal heat sink in the heat dissipation of high power light emitting diode (LED), a kind of miniaturized phase change heat sink is developed for high power LED packaging. First, t...In view of the limitations of solid metal heat sink in the heat dissipation of high power light emitting diode (LED), a kind of miniaturized phase change heat sink is developed for high power LED packaging. First, the fabrication process of miniaturized phase change heat sink is investigated, upon which all parts of the heat sink are fabricated including main-body and end-cover of the heat sink, the formation of three-dimensional boiling structures at the evaporation end, the sintering of the wick, and the encapsulation of high power LED phase change heat sink. Subsequently, with the assistance of the developed testing system, heat transfer performance of the heat sink is tested under the condition of natural convection, upon which the influence of thermal load and working medium on the heat transfer performance is investigated. Finally, the heat transfer performance of the developed miniaturized phase change heat sink is compared with that of metal solid heat sink. Results show that the developed miniaturized phase change heat sink presents much better heat transfer performance over traditional metal solid heat sink, and is suitable for the packaging of high power LED.展开更多
Most materials can be easily corroded or ineffective in carbonaceous atmospheres at high temperatures in the reactor core of the high temperature gas-cooled reactor(HTGR).To solve the problem,a material performance te...Most materials can be easily corroded or ineffective in carbonaceous atmospheres at high temperatures in the reactor core of the high temperature gas-cooled reactor(HTGR).To solve the problem,a material performance test apparatus was built to provide reliable materials and technical support for relevant experiments of the HTGR.The apparatus uses a center high-purity graphite heater and surrounding thermal insulating layers made of carbon fiber felt to form a strong carbon reducing atmosphere inside the apparatus.Specially designed tungsten rhenium thermocouples which can endure high temperatures in carbonaceous atmospheres are used to control the temperature field.A typical experimental process was analyzed in the paper,which lasted 76 hours including seven stages.Experimental results showed the test apparatus could completely simulate the carbon reduction atmosphere and high temperature environment the same as that confronted in the real reactor and the performance of screened materials had been successfully tested and verified.Test temperature in the apparatus could be elevated up to 1600oC,which covered the whole temperature range of the normal operation and accident condition of HTGR and could fully meet the test requirements of materials used in the reactor.展开更多
Tractor hydraulic fluids are tested to maximize their performance levels and to ensure manufacturer′s standards are met.Common tractor hydraulic fluid tests include: Gear Wear Protection,Brake Chatter Reduction,Wet-C...Tractor hydraulic fluids are tested to maximize their performance levels and to ensure manufacturer′s standards are met.Common tractor hydraulic fluid tests include: Gear Wear Protection,Brake Chatter Reduction,Wet-Clutch Capacity,and Pump Performance tests.These tests are run by Southwest Research Institute,in the U.S.A.,for tractors built by John Deere and Case-New Holland.This paper details current methods for evaluating tractor hydraulic fluids.The tests that are described utilize full size equipment and were developed by the tractor′s original equipment manufacturers(OEMs).展开更多
Customizing applications through program configuration options has been proved by many open-source and commercial projects as one of the best practices in software engineering. However, traditional performance testing...Customizing applications through program configuration options has been proved by many open-source and commercial projects as one of the best practices in software engineering. However, traditional performance testing is not in synch with this industrial practice. Traditional performance testing techniques consider program inputs as the only external factor. It ignores the performance influence of configuration options. This study aims to stimulate research interest in performance testing in the context of configurable software systems by answering three research questions. That is, why it is necessary to conduct research in performance testing, what are the state-of-the-art techniques, and how do we conduct performance testing research in configurable software systems. In this study, we examine the unique characteristics and challenges of performance testing research in configurable software systems. We review and discuss research topics on the performance bug study, performance anti-patterns, program analysis, and performance testing. We share the research findings from the empirical study and outline the opening opportunities for new and advanced researchers to contribute to the research community.展开更多
Based on the 1D-blade element momentum theory (BEM) with the improved tip loss correction introduced, a new aerodynamic model of wind turbine is developed. Using one high aerodynamic performance airfoil with 18% relat...Based on the 1D-blade element momentum theory (BEM) with the improved tip loss correction introduced, a new aerodynamic model of wind turbine is developed. Using one high aerodynamic performance airfoil with 18% relative thickness, one small wind turbine blade is designed and the distribution of the chord and twist angle of the blade are determined. According to the shape parameters of the blade, a method to set up the 3D model is presented by investigating the coordinate position of each section of the blade. Based on the fiber reinforced polymer (FRP) molding technology, the manufacturing process of wind turbine blade is put forward. Using fiber reinforced polymer, the wind turbine blades are manufactured by the mold making and layer process. A test platform and method of wind turbine output power are carried out, the output powers at different speeds of the wind turbine are obtained and discussed. The comparison between the designed and one existing wind turbine rotor is completed to show the reliability and superiority of the design and test method presented in this paper.展开更多
Three progressive stages of testing techniques are elaborated,which are en-tirely manual operating,taking separate instruments testing and computer program con-trolling.The testing method and principle are detailed ba...Three progressive stages of testing techniques are elaborated,which are en-tirely manual operating,taking separate instruments testing and computer program con-trolling.The testing method and principle are detailed based on the testing process formeteorological parameters,air pressure,air quality and rotating velocity.And every testingtechnique is analyzed.Finally, the technique outlook is viewed.All this plays a leading rolein development of the testing techniques.展开更多
he thermal performance test of the horizontal coaxial double tube hot gas duct (HGD) with an internal thermal insulation for the 10MW High Temperature Reactor Test Module (HTR10) was conducted on a Helium Test Loop(HE...he thermal performance test of the horizontal coaxial double tube hot gas duct (HGD) with an internal thermal insulation for the 10MW High Temperature Reactor Test Module (HTR10) was conducted on a Helium Test Loop(HETL). The present paper deals with the technical feature of the HETL, the test section and the thermal performance test of the HGD. The HGD test section with a triple tube structure includes an inner heater, a HGD model and a coldhot gas mixer. A counterflow of cold and hot helium gas under the pressure of about 3.0 MPa and the minimum temperature of 100℃ in the annular passage and the maximum of 950℃ in the central tube of the HGD model was formed. The HGD model was undergone 20 times of pressure cycle test under the pressure ranging from 0.1 to 3.4 MPa, 18 times of the temperature cycle test under the temperature ranging from 100 to 950℃ and high temperature (700 to 950℃) helium flow test for a period of more than 350 hours. The effective thermal conductivity (λeff) of the internal insulation of the HGD was investigated experimentally. The relationship of the effective thermal conductivity with the average tmperature of the internal insulation layer is λeff(W/m/℃)=0.3512+0.0003T(℃). The test results indicate that the HGD model has good abilities to resist heat flux from the central tube to the annular passage, temperature variations, and pressure variations.展开更多
The field tot of performance of mine main fan is going to become an independance requirement of coal mlue progressively and to be taken seriously. According to the fan-house with air gate closed to the fan inlet, this...The field tot of performance of mine main fan is going to become an independance requirement of coal mlue progressively and to be taken seriously. According to the fan-house with air gate closed to the fan inlet, this paper analyses the influence of the rapid changing air flow field upon field test and puts forward a reasonable test scheme.展开更多
The performance test of Intelligent Network (IN) system is an important phase in developing IN system. We designed a set of simple and practical methods on the basis of the characteristics of IN for the performance te...The performance test of Intelligent Network (IN) system is an important phase in developing IN system. We designed a set of simple and practical methods on the basis of the characteristics of IN for the performance test of the prototype of the BUPT-IN system. The test result is well satisfied and shows that the performance of the BUPT-IN system reaches the original goal.展开更多
Condenser is one of the important auxiliary equipments in nuclear power plants. The thermal efficiency of the entire unit was depended on the condenser performance. Cleanliness factor and condenser corrected pressure ...Condenser is one of the important auxiliary equipments in nuclear power plants. The thermal efficiency of the entire unit was depended on the condenser performance. Cleanliness factor and condenser corrected pressure are the two most important evaluation indexes. The definition and derivation of these two evaluation indexes were elaborated and clarified in this paper. And the condenser performance at variable conditions was analyzed. The seawater temperature, pipe plugging rate and seawater volume rate effect on unit output was calculated. The calculation method was simple, which can provide reference guidance for similar power plant.展开更多
Data consisting of test performance records of 725 bulls was analysed to evaluate trends for growth and feed efficiency, and to determine environmental factors that influence growth of range performance tested bulls i...Data consisting of test performance records of 725 bulls was analysed to evaluate trends for growth and feed efficiency, and to determine environmental factors that influence growth of range performance tested bulls in the arid sweet bushveld of South Africa. Performance data were subjected to regression procedures to estimate parameters of the slope (β) and intercept (α) for average daily gain (ADG) and Kleiber ratio (KR). Mixed procedures were applied to test for sources of variation in ADG and KR. There was an increase of 3.481 g/day/year and 0.528 g/day/ year in ADG for Nguni and Bonsmara bulls, respectively. The ADG trends’ respective feed efficiency as reflected by KR was 0.093 and 0.059. Herd of origin and test-year were the sources of variation for ADG while the variation in KR was due to the herd of origin, test-year, start-age and start-weight. Results indicated a steady increase in ADG and KR for range performance tested bulls in the arid sweet bushveld.展开更多
Background and Aim: Given the dramatic decline in the ability of test due to test anxiety, the goal of this study was to evaluate the relationship between test anxiety and academic performances in students. Materials ...Background and Aim: Given the dramatic decline in the ability of test due to test anxiety, the goal of this study was to evaluate the relationship between test anxiety and academic performances in students. Materials and Methods: This descriptive-analytical study was performed on 216 Iranian nursing and midwifery students in 2011-2012, utilizing Sarason Anxiety Inventory, demographic checklist and the average mark of students in the period of midterm and final exam. Multinomial logistic regression analyses by reporting odds ratios and their 95% confidence intervals were performed by SPSS17 software to assess the relationship between test anxiety and academic performances. Results: Mild, moderate and sever test anxiety was observed in 30.6, 43.1 and 26.4 percent of students respectively. Test anxiety was significantly related to academic performance (average), major and city. Also, there was 52.9% decrease for odds of having sever anxiety (compared to mild anxiety) with 1 point increase in average (OR = 0.471, 95% CI = (0.298 - 0.745) and p = 0.001). Conclusions: Due to inverse relationship between test anxiety and academic performance, performing preventive programs such as in time treatment of anxiety, empowering the students to deal with anxiety and conducting consulting services for how to studying are very important. Consequently it would be a big step in decreasing the test anxiety and therefore in improving the academic performance.展开更多
In a performance test, the standards for assessing its test results are not sufficiently determined due to the lack of a well-structured test developing methods which are found in a functionality test. By extending th...In a performance test, the standards for assessing its test results are not sufficiently determined due to the lack of a well-structured test developing methods which are found in a functionality test. By extending the established workflow structure, this approach will concentrate on tradeoffs within T-workflow and further develop tests based on T-workflow. The monitoring and tuning point have also been investigated to understand the validity and performance of software. Finally through a case study, it has been shown that better assessment of software performance can be obtained with the suggested tests developed based on T-workflow and by locating its monitoring point and tuning point.展开更多
To improve the transmission accuracy and stiffness of the ball cycloid reducer, the authors developed a novel cycloid ball reducer, which uses a full complement ball as its gear teeth. Ceramic balls are used to get be...To improve the transmission accuracy and stiffness of the ball cycloid reducer, the authors developed a novel cycloid ball reducer, which uses a full complement ball as its gear teeth. Ceramic balls are used to get better performance in severe working conditions. A simple synthesis method was also found to determine the raceway forms and compute the contact forces among the balls and raceways. The Contact Stress Analysis (CSA) computer program was used to optimize the design of the reducer. In this paper, the following topics are covered: (1) Study of the geometry of the raceways. (2) Analyses of the principal curvature of the raceways are also accomplished. In addition, the modification of the raceway is put forward. (3) The contact forces and the reducer efficiency are evaluated. (4) Study of the performance of ceramic balls used in the CBR. A reducer using the above design technique was tested and the performances show that the reducer has high precision and rigidity. An increase of more than 50 percent transmission power was realized in the new gearing.展开更多
This study focuses on testing and quality measurement and analysis of VoIPv6 performance. A client, server codes were developed using FreeBSD. This is a step before analyzing the Architectures of VoIPv6 in the current...This study focuses on testing and quality measurement and analysis of VoIPv6 performance. A client, server codes were developed using FreeBSD. This is a step before analyzing the Architectures of VoIPv6 in the current internet in order for it to cope with IPv6 traffic transmission requirements in general and specifically voice traffic, which is being attracting the efforts of research, bodes currently. These tests were conducted in the application level without looking into the network level of the network. VoIPv6 performance tests were conducted in the current tunneled and native IPv6 aiming for better end-to-end VoIPv6 performance. The results obtained in this study were shown in deferent codec's for different bit rates in Kilo bits per second, which act as an indicator for the better performance of G.711 compared with the rest of the tested codes.展开更多
Taking a 2.5 liter accumulator with hydro-pneumatic suspension in a CXP1032 crane made in Germany as the research object and taking both the overall-road simulative test-bed and the control equipment made by the Schen...Taking a 2.5 liter accumulator with hydro-pneumatic suspension in a CXP1032 crane made in Germany as the research object and taking both the overall-road simulative test-bed and the control equipment made by the Schenck Company of Germany as the testing instrument, the structure performance and mechanism are theoretically clarified and the variation of gas states are obtained. This illustrates the accumulating and releasing process of a 2.5 liter accumulator in a 32t crane in the real condition. The preliminary volume and pressure of accumulator would directly affect the stiffness performance of the hydro-pneumatic suspension in a vehicle.展开更多
Earthquake investigations have illustrated that even code-compliant reinforced concrete frames may suffer from soft-story mechanism.This damage mode results in poor ductility and limited energy dissipation.Continuous ...Earthquake investigations have illustrated that even code-compliant reinforced concrete frames may suffer from soft-story mechanism.This damage mode results in poor ductility and limited energy dissipation.Continuous components offer alternatives that may avoid such failures.A novel infilled rocking wall frame system is proposed that takes advantage of continuous component and rocking characteristics.Previous studies have investigated similar systems that combine a reinforced concrete frame and a wall with rocking behavior used.However,a large-scale experimental study of a reinforced concrete frame combined with a rocking wall has not been reported.In this study,a seismic performance evaluation of the newly proposed infilled rocking wall frame structure was conducted through quasi-static cyclic testing.Critical joints were designed and verified.Numerical models were established and calibrated to estimate frame shear forces.The results evaluation demonstrate that an infilled rocking wall frame can effectively avoid soft-story mechanisms.Capacity and initial stiffness are greatly improved and self-centering behavior is achieved with the help of the infilled rocking wall.Drift distribution becomes more uniform with height.Concrete cracks and damage occurs in desired areas.The infilled rocking wall frame offers a promising approach to achieving seismic resilience.展开更多
文摘Automotive-grade Complementary Metal-Oxide-Semiconductor(CMOS)sensors play a crucial role in automotive electronic systems,especially in the context of the rapid development of Advanced Driver Assistance Systems(ADAS)and autonomous driving technologies.Their performance is directly related to the safety and reliability of vehicles.However,automobiles will face a variety of complex environmental conditions during the actual operation,such as high temperature,low temperature,vibration,humidity changes,and light changes,which may have an impact on the performance of CMOS sensors.Therefore,it is of great significance to study the performance of automotive-grade CMOS sensors in different environments.
文摘To realize automatic control of automobile transmission performance test stand Methods The automatic control technique of the lubricant temperature,the program- controll- edautomaticshifting of the transmission,the continuous adjusting of revolution speed and load, data-acquisition and data real-time processing were adopted.Results The lubricant temperature was controlled at the set temperature ±2℃.The automatic shifting of the trans- mission is simple,reliable and accurate.The automatic adjusting of load and rotation speed is rapidandaccurate,the torque divergence is ±1N·m,the rotation speed divergence is ±5r/min Conclusion The four kinds of techniques are applied into the automobile transmission perfor- mance test stand successfully. mancetest stand successfully.
基金Projects(51575115,51775122)supported by the National Natural Science Foundation of China
文摘In view of the limitations of solid metal heat sink in the heat dissipation of high power light emitting diode (LED), a kind of miniaturized phase change heat sink is developed for high power LED packaging. First, the fabrication process of miniaturized phase change heat sink is investigated, upon which all parts of the heat sink are fabricated including main-body and end-cover of the heat sink, the formation of three-dimensional boiling structures at the evaporation end, the sintering of the wick, and the encapsulation of high power LED phase change heat sink. Subsequently, with the assistance of the developed testing system, heat transfer performance of the heat sink is tested under the condition of natural convection, upon which the influence of thermal load and working medium on the heat transfer performance is investigated. Finally, the heat transfer performance of the developed miniaturized phase change heat sink is compared with that of metal solid heat sink. Results show that the developed miniaturized phase change heat sink presents much better heat transfer performance over traditional metal solid heat sink, and is suitable for the packaging of high power LED.
基金Supported by the National S&T Major Project of China(No.ZX06901)the National Natural Science Foundation of China(No 11072131)
文摘Most materials can be easily corroded or ineffective in carbonaceous atmospheres at high temperatures in the reactor core of the high temperature gas-cooled reactor(HTGR).To solve the problem,a material performance test apparatus was built to provide reliable materials and technical support for relevant experiments of the HTGR.The apparatus uses a center high-purity graphite heater and surrounding thermal insulating layers made of carbon fiber felt to form a strong carbon reducing atmosphere inside the apparatus.Specially designed tungsten rhenium thermocouples which can endure high temperatures in carbonaceous atmospheres are used to control the temperature field.A typical experimental process was analyzed in the paper,which lasted 76 hours including seven stages.Experimental results showed the test apparatus could completely simulate the carbon reduction atmosphere and high temperature environment the same as that confronted in the real reactor and the performance of screened materials had been successfully tested and verified.Test temperature in the apparatus could be elevated up to 1600oC,which covered the whole temperature range of the normal operation and accident condition of HTGR and could fully meet the test requirements of materials used in the reactor.
文摘Tractor hydraulic fluids are tested to maximize their performance levels and to ensure manufacturer′s standards are met.Common tractor hydraulic fluid tests include: Gear Wear Protection,Brake Chatter Reduction,Wet-Clutch Capacity,and Pump Performance tests.These tests are run by Southwest Research Institute,in the U.S.A.,for tractors built by John Deere and Case-New Holland.This paper details current methods for evaluating tractor hydraulic fluids.The tests that are described utilize full size equipment and were developed by the tractor′s original equipment manufacturers(OEMs).
文摘Customizing applications through program configuration options has been proved by many open-source and commercial projects as one of the best practices in software engineering. However, traditional performance testing is not in synch with this industrial practice. Traditional performance testing techniques consider program inputs as the only external factor. It ignores the performance influence of configuration options. This study aims to stimulate research interest in performance testing in the context of configurable software systems by answering three research questions. That is, why it is necessary to conduct research in performance testing, what are the state-of-the-art techniques, and how do we conduct performance testing research in configurable software systems. In this study, we examine the unique characteristics and challenges of performance testing research in configurable software systems. We review and discuss research topics on the performance bug study, performance anti-patterns, program analysis, and performance testing. We share the research findings from the empirical study and outline the opening opportunities for new and advanced researchers to contribute to the research community.
基金Supported by the National Natural Science Foundation of China(No.51205430)Chongqing Foundation and Frontier Project(No.cstc2016jcyjA0448)Chongqing Municipal Education Commission Scientific Research Project(No.KJ1600628)
文摘Based on the 1D-blade element momentum theory (BEM) with the improved tip loss correction introduced, a new aerodynamic model of wind turbine is developed. Using one high aerodynamic performance airfoil with 18% relative thickness, one small wind turbine blade is designed and the distribution of the chord and twist angle of the blade are determined. According to the shape parameters of the blade, a method to set up the 3D model is presented by investigating the coordinate position of each section of the blade. Based on the fiber reinforced polymer (FRP) molding technology, the manufacturing process of wind turbine blade is put forward. Using fiber reinforced polymer, the wind turbine blades are manufactured by the mold making and layer process. A test platform and method of wind turbine output power are carried out, the output powers at different speeds of the wind turbine are obtained and discussed. The comparison between the designed and one existing wind turbine rotor is completed to show the reliability and superiority of the design and test method presented in this paper.
文摘Three progressive stages of testing techniques are elaborated,which are en-tirely manual operating,taking separate instruments testing and computer program con-trolling.The testing method and principle are detailed based on the testing process formeteorological parameters,air pressure,air quality and rotating velocity.And every testingtechnique is analyzed.Finally, the technique outlook is viewed.All this plays a leading rolein development of the testing techniques.
文摘he thermal performance test of the horizontal coaxial double tube hot gas duct (HGD) with an internal thermal insulation for the 10MW High Temperature Reactor Test Module (HTR10) was conducted on a Helium Test Loop(HETL). The present paper deals with the technical feature of the HETL, the test section and the thermal performance test of the HGD. The HGD test section with a triple tube structure includes an inner heater, a HGD model and a coldhot gas mixer. A counterflow of cold and hot helium gas under the pressure of about 3.0 MPa and the minimum temperature of 100℃ in the annular passage and the maximum of 950℃ in the central tube of the HGD model was formed. The HGD model was undergone 20 times of pressure cycle test under the pressure ranging from 0.1 to 3.4 MPa, 18 times of the temperature cycle test under the temperature ranging from 100 to 950℃ and high temperature (700 to 950℃) helium flow test for a period of more than 350 hours. The effective thermal conductivity (λeff) of the internal insulation of the HGD was investigated experimentally. The relationship of the effective thermal conductivity with the average tmperature of the internal insulation layer is λeff(W/m/℃)=0.3512+0.0003T(℃). The test results indicate that the HGD model has good abilities to resist heat flux from the central tube to the annular passage, temperature variations, and pressure variations.
文摘The field tot of performance of mine main fan is going to become an independance requirement of coal mlue progressively and to be taken seriously. According to the fan-house with air gate closed to the fan inlet, this paper analyses the influence of the rapid changing air flow field upon field test and puts forward a reasonable test scheme.
基金Sponsored by Doctoral Research Fund of State Educational Commission of China
文摘The performance test of Intelligent Network (IN) system is an important phase in developing IN system. We designed a set of simple and practical methods on the basis of the characteristics of IN for the performance test of the prototype of the BUPT-IN system. The test result is well satisfied and shows that the performance of the BUPT-IN system reaches the original goal.
文摘Condenser is one of the important auxiliary equipments in nuclear power plants. The thermal efficiency of the entire unit was depended on the condenser performance. Cleanliness factor and condenser corrected pressure are the two most important evaluation indexes. The definition and derivation of these two evaluation indexes were elaborated and clarified in this paper. And the condenser performance at variable conditions was analyzed. The seawater temperature, pipe plugging rate and seawater volume rate effect on unit output was calculated. The calculation method was simple, which can provide reference guidance for similar power plant.
文摘Data consisting of test performance records of 725 bulls was analysed to evaluate trends for growth and feed efficiency, and to determine environmental factors that influence growth of range performance tested bulls in the arid sweet bushveld of South Africa. Performance data were subjected to regression procedures to estimate parameters of the slope (β) and intercept (α) for average daily gain (ADG) and Kleiber ratio (KR). Mixed procedures were applied to test for sources of variation in ADG and KR. There was an increase of 3.481 g/day/year and 0.528 g/day/ year in ADG for Nguni and Bonsmara bulls, respectively. The ADG trends’ respective feed efficiency as reflected by KR was 0.093 and 0.059. Herd of origin and test-year were the sources of variation for ADG while the variation in KR was due to the herd of origin, test-year, start-age and start-weight. Results indicated a steady increase in ADG and KR for range performance tested bulls in the arid sweet bushveld.
文摘Background and Aim: Given the dramatic decline in the ability of test due to test anxiety, the goal of this study was to evaluate the relationship between test anxiety and academic performances in students. Materials and Methods: This descriptive-analytical study was performed on 216 Iranian nursing and midwifery students in 2011-2012, utilizing Sarason Anxiety Inventory, demographic checklist and the average mark of students in the period of midterm and final exam. Multinomial logistic regression analyses by reporting odds ratios and their 95% confidence intervals were performed by SPSS17 software to assess the relationship between test anxiety and academic performances. Results: Mild, moderate and sever test anxiety was observed in 30.6, 43.1 and 26.4 percent of students respectively. Test anxiety was significantly related to academic performance (average), major and city. Also, there was 52.9% decrease for odds of having sever anxiety (compared to mild anxiety) with 1 point increase in average (OR = 0.471, 95% CI = (0.298 - 0.745) and p = 0.001). Conclusions: Due to inverse relationship between test anxiety and academic performance, performing preventive programs such as in time treatment of anxiety, empowering the students to deal with anxiety and conducting consulting services for how to studying are very important. Consequently it would be a big step in decreasing the test anxiety and therefore in improving the academic performance.
文摘In a performance test, the standards for assessing its test results are not sufficiently determined due to the lack of a well-structured test developing methods which are found in a functionality test. By extending the established workflow structure, this approach will concentrate on tradeoffs within T-workflow and further develop tests based on T-workflow. The monitoring and tuning point have also been investigated to understand the validity and performance of software. Finally through a case study, it has been shown that better assessment of software performance can be obtained with the suggested tests developed based on T-workflow and by locating its monitoring point and tuning point.
文摘To improve the transmission accuracy and stiffness of the ball cycloid reducer, the authors developed a novel cycloid ball reducer, which uses a full complement ball as its gear teeth. Ceramic balls are used to get better performance in severe working conditions. A simple synthesis method was also found to determine the raceway forms and compute the contact forces among the balls and raceways. The Contact Stress Analysis (CSA) computer program was used to optimize the design of the reducer. In this paper, the following topics are covered: (1) Study of the geometry of the raceways. (2) Analyses of the principal curvature of the raceways are also accomplished. In addition, the modification of the raceway is put forward. (3) The contact forces and the reducer efficiency are evaluated. (4) Study of the performance of ceramic balls used in the CBR. A reducer using the above design technique was tested and the performances show that the reducer has high precision and rigidity. An increase of more than 50 percent transmission power was realized in the new gearing.
文摘This study focuses on testing and quality measurement and analysis of VoIPv6 performance. A client, server codes were developed using FreeBSD. This is a step before analyzing the Architectures of VoIPv6 in the current internet in order for it to cope with IPv6 traffic transmission requirements in general and specifically voice traffic, which is being attracting the efforts of research, bodes currently. These tests were conducted in the application level without looking into the network level of the network. VoIPv6 performance tests were conducted in the current tunneled and native IPv6 aiming for better end-to-end VoIPv6 performance. The results obtained in this study were shown in deferent codec's for different bit rates in Kilo bits per second, which act as an indicator for the better performance of G.711 compared with the rest of the tested codes.
文摘Taking a 2.5 liter accumulator with hydro-pneumatic suspension in a CXP1032 crane made in Germany as the research object and taking both the overall-road simulative test-bed and the control equipment made by the Schenck Company of Germany as the testing instrument, the structure performance and mechanism are theoretically clarified and the variation of gas states are obtained. This illustrates the accumulating and releasing process of a 2.5 liter accumulator in a 32t crane in the real condition. The preliminary volume and pressure of accumulator would directly affect the stiffness performance of the hydro-pneumatic suspension in a vehicle.
基金Natural Science Foundation of China under Grant Nos.51178342 and 51578314
文摘Earthquake investigations have illustrated that even code-compliant reinforced concrete frames may suffer from soft-story mechanism.This damage mode results in poor ductility and limited energy dissipation.Continuous components offer alternatives that may avoid such failures.A novel infilled rocking wall frame system is proposed that takes advantage of continuous component and rocking characteristics.Previous studies have investigated similar systems that combine a reinforced concrete frame and a wall with rocking behavior used.However,a large-scale experimental study of a reinforced concrete frame combined with a rocking wall has not been reported.In this study,a seismic performance evaluation of the newly proposed infilled rocking wall frame structure was conducted through quasi-static cyclic testing.Critical joints were designed and verified.Numerical models were established and calibrated to estimate frame shear forces.The results evaluation demonstrate that an infilled rocking wall frame can effectively avoid soft-story mechanisms.Capacity and initial stiffness are greatly improved and self-centering behavior is achieved with the help of the infilled rocking wall.Drift distribution becomes more uniform with height.Concrete cracks and damage occurs in desired areas.The infilled rocking wall frame offers a promising approach to achieving seismic resilience.