This paper proposes teaching reforms in communication engineering majors,emphasizing the implementation of digital and adaptive teaching methodologies,integrating emerging technologies,breaking free from the constrain...This paper proposes teaching reforms in communication engineering majors,emphasizing the implementation of digital and adaptive teaching methodologies,integrating emerging technologies,breaking free from the constraints of traditional education,and fostering high-caliber talents.The reform measures encompass fundamental data collection,recognition of individual characteristics,recommendation of adaptive learning resources,process-oriented teaching management,adaptive student guidance and early warning systems,personalized evaluation,and the construction of an integrated service platform.These measures,when combined,form a comprehensive system that is expected to enhance teaching quality and efficiency,and facilitate student development.展开更多
The environmental damage arising from the construction and engineering services was responsible for the appearance of several norms and resolutions regulating and directing the sector’s performance. In this article, ...The environmental damage arising from the construction and engineering services was responsible for the appearance of several norms and resolutions regulating and directing the sector’s performance. In this article, we research how professionals with experience in public bids assess the difficulty degree of the implementation of those requirements and how they assess the environmental legislation regarding the protection and conservation of the environment, impact on costs, deadlines and the solution to environmental problems. The results show that industry professionals consider as “high” the level of difficulty to implement the addressed sustainability requirements, and that the Brazilian environmental legislation does not comply with its environmental protection role, increases the possibility of delays and costs of projects and services and hampers the emergence of solutions that could solve environmental problems.展开更多
“Service Engineering”is a computer professional course with profound theory,extensive coverage and marked features of engineering.This article will analyze the characteristics of this course,the challenges we’ve en...“Service Engineering”is a computer professional course with profound theory,extensive coverage and marked features of engineering.This article will analyze the characteristics of this course,the challenges we’ve encountered in the teaching process and a summary of our solutions.We hope that our work is helpful for other service engineering courses or similar courses.展开更多
In view of the problems of inconsistent data semantics,inconsistent data formats,and difficult data quality assurance between the railway engineering design phase and the construction and operation phase,as well as th...In view of the problems of inconsistent data semantics,inconsistent data formats,and difficult data quality assurance between the railway engineering design phase and the construction and operation phase,as well as the difficulty in fully realizing the value of design results,this paper proposes a design and implementation scheme for a railway engineering collaborative design platform.The railway engineering collaborative design platform mainly includes functional modules such as metadata management,design collaboration,design delivery management,model component library,model rendering services,and Building Information Modeling(BIM)application services.Based on this,research is conducted on multi-disciplinary parameterized collaborative design technology for railway engineering,infrastructure data management and delivery technology,and design multi-source data fusion and application technology.The railway engineering collaborative design platform is compared with other railway design software to further validate its advantages and advanced features.The platform has been widely applied in multiple railway construction projects,greatly improving the design and project management efficiency.展开更多
This paper first introduces the basic connotation of China’s whole-process engineering consulting.Immediately,analyze the organization model,service procurement model and charging standards of foreign whole-process e...This paper first introduces the basic connotation of China’s whole-process engineering consulting.Immediately,analyze the organization model,service procurement model and charging standards of foreign whole-process engineering consulting(international terminology full-life cycle engineering consultant).Second,discuss the government’s role in the development of engineering consulting from two aspects:service management and market access.Finally,combined with the above analysis,the specific problems faced in the implementation process of the whole process engineering consulting are compared.Provide relevant suggestions on how companies and individuals respond to industry development trends.展开更多
An approach to traffic engineering that uses differentiated services (DS) andmulti-protocol label switching (MPLS) to provide quantitative network quality of service (QoS)guarantees over an IP network was proposed. Th...An approach to traffic engineering that uses differentiated services (DS) andmulti-protocol label switching (MPLS) to provide quantitative network quality of service (QoS)guarantees over an IP network was proposed. The traffic associated with assured forwarding (AF)Per-Hop behavior (PHB) in differentiated services enabled IP network was modeled. Furthermore, theeffect of such traffic on network resources with die objective of developing efficient trafficengineering methodologies was analyzed and the optimization problem relating to traffic engineeringin DS networks with an MPLS core was formulated. The service received by TCP and UDP flows when theyshare either a link or a MPLS traffic trunk was also compared and found that in order to benefitfrom traffic engineering, MPLS trunks should be implemented end-end (first router to last router).If some part of the network is MPLS trunk-unaware, the benefits are reduced or eliminated.展开更多
The ecosystem service value of Jingtaichuan electric power irrigation engineering( referred to as Jingdian engineering) was divided into internal value( the value of farmland system,shelter forest system outside of fa...The ecosystem service value of Jingtaichuan electric power irrigation engineering( referred to as Jingdian engineering) was divided into internal value( the value of farmland system,shelter forest system outside of farmland and wetland waters) and external value( the ecological service value of ecological migration to the vegetation restoration of the Qilian Mountains) firstly,and then it was analyzed by using the model method and the factor equivalent method. The results showed that the internal ecological service value of Jingdian engineering was 36. 3 ×10~8 yuan,which was 25. 0 times larger than the total annual cost. The external ecological service value was 40. 05 ×10~8 yuan,which was 27. 6 times larger than the total annual cost. Among the three functional systems,the ecological service value of farmland system was the largest. The ecological service value of farmland system was mainly reflected in waste disposal,wind prevention and sand fixation,and food production. The external ecological service value was mainly the ecological service value of migration to vegetation restoration in the Qilian Mountains. Jingdian engineering is the only highlifting project that raises water to the desert in China. It transfers water from outer basins to control desertification and provides a successful road for ecological migration and desertification control in arid areas.展开更多
To meet the actual requirements of an automotive industry chain collaboration platform (AICCP), this paper offers several simple but effective security policies based upon the traditional security mechanism of data ...To meet the actual requirements of an automotive industry chain collaboration platform (AICCP), this paper offers several simple but effective security policies based upon the traditional security mechanism of data transfer, including user ID verification with SOAP (simple object access protocol), header, SOAP message encryption with SOAP extension and XML (extensible markup language) file encryption and decryption. Application of these policies to the AICCP for more than one year proves the effectiveness of the data exchange practice between the AICCP and enterprise Intranet.展开更多
Substantially lightweight brake discs with high wear resistance are highly desirable in the automotive industry.This paper presents an investigation of the precision-engineering design and development of automotive br...Substantially lightweight brake discs with high wear resistance are highly desirable in the automotive industry.This paper presents an investigation of the precision-engineering design and development of automotive brake discs using nonhomogeneous Al/SiC metal-matrixcomposite materials.The design and development are based on modeling and analysis following stringent precision-engineering principles,i.e.,brake-disc systems that operate repeatably and stably over time as enabled by precision-engineering design.The design and development are further supported by tribological experimental testing and finite-element simulations.The results show the industrial feasibility of the innovative design approach and the application merits of using advanced metal-matrix-composite materials for next-generation automotive and electric vehicles.展开更多
The research dealt with assessment of logistics service providers' capabilities in SECs (supporting subsea engineering companies) on the Tweneboa, Enyenra and Ntomme (TEN) project in Ghana. SECs need logistics se...The research dealt with assessment of logistics service providers' capabilities in SECs (supporting subsea engineering companies) on the Tweneboa, Enyenra and Ntomme (TEN) project in Ghana. SECs need logistics service providers who offer consolidated services for project optimization and fulfillment of local content requirements of the project. Relevant Staffof7 SECs and 10 logistics service providers in Ghana formed part of the target group. The weighted scoring model was used in selecting a logistics service provider based on certain criteria. The selection criteria included Quality, Health, Safety and Environmental (QHSE) policies [Q], Compliance to regulations (GRA, Work permit, petroleum regulation) [C], Delivery of goods on time and response rate to deliver [D], Vessel, Cargo attendance and transportation (sea freight and air freight) [V], and Logistics (Personal logistics and Logistics base facilities) [L]. The study concluded Consolidated Shipping Agency (Conship) was the best Logistics Service Provider to offer the best consolidated services for project optimization under the TEN project.展开更多
In recent years, agile methodologies have been consolidated and extended in organizations that develop software in Web environments. For this reason, the development methodology of these organizations will not only be...In recent years, agile methodologies have been consolidated and extended in organizations that develop software in Web environments. For this reason, the development methodology of these organizations will not only be related to Services, but also to the Web Engineering paradigm. These organizations are heading for incorporating software development methodologies whose paradigm can allow integration, naturally and in the earlier stages of Web applications develop with the services of the organization that described and published in the Services Portfolio. The aim of this study will be to analyze the current state of the art in the process of discovering services in early stages of agile software development with focus on those identified requirements that could be covered with the services included in the Service Portfolio. We have identified 20 relevant papers through conducting a double systematic literature review (SLR). It is concluded that no study has been found that can solve the entire process of discovering candidate services within an organization that cover the requirements of a new application developed with agile methodologies. At the same time, guidelines have been found to formalize the solution to this problem and fill in that gap of knowledge by proposing in a single process, the formalization of a requirement based on agile techniques, which can be managed against a Services Portfolio.展开更多
Reducing heat accumulation within vehicles and ensuring appropriate vehicular temperature levels can lead to enhanced vehicle fuel economy,range,reliability,longevity,passenger comfort,and safety.Advancements in vehic...Reducing heat accumulation within vehicles and ensuring appropriate vehicular temperature levels can lead to enhanced vehicle fuel economy,range,reliability,longevity,passenger comfort,and safety.Advancements in vehicle thermal management remain key as new technologies,consumer demand,societal concerns,and government regulations emerge and evolve.This study summarizes several recent advances in vehicle thermal management technology and modeling,with a focus on three key areas:the cabin,electronics,and exterior components of vehicles.Cabin-related topics covered include methods for reducing thermal loads and improving heating,ventilation,and air-conditioning(HVAC)systems;and advancements in window glazing/tinting and vehicle surface treatments.For the thermal management of electronics,including batteries and insulated-gate bipolar transistors(IGBTs),active and passive cooling methods that employ heat pipes,heat sinks,jet impingement,forced convection,and phase-change materials are discussed.Finally,efforts to model and enhance the heat transfer of exterior vehicular components are reviewed while considering drag/friction forces and environmental effects.Despite advances in the field of vehicle thermal management,challenges still exist;this article provides a broad summary of the major issues,with recommendations for further study.展开更多
The multi-impact characteristics and failure mechanism of two kinds of automotive engine chain made in China are studied through engine assembly and road-drive tests. The worn surface morphologies of rubbing area betw...The multi-impact characteristics and failure mechanism of two kinds of automotive engine chain made in China are studied through engine assembly and road-drive tests. The worn surface morphologies of rubbing area between pin, bush and roller are also analyzed based on scanning electron microscope. The results show that the main wear mechanism of automotive engine chain is fatigue wear, and its failure mechanism is the forming, extending and flaking of cracks on top layer of pin and bush. In addition, the material, hot-treatment method and shaping technique for roller have a great influence upon the resistance to multi-impact. Ensuring sufficient strength and plasticity of roller, as well as adopting suitable shaping technique are the effective method to increase its resistance to multi-impact.展开更多
The high-speed multi-cycle impact and speed, load fluctuant characteristics of a kind of narrow-width automotive engine oil-pump chain 06BN-1 are studied through engine assembly and road-drive tests to satisfy the lig...The high-speed multi-cycle impact and speed, load fluctuant characteristics of a kind of narrow-width automotive engine oil-pump chain 06BN-1 are studied through engine assembly and road-drive tests to satisfy the light-weight demand of engine. The worn surface morphologies of rubbing area between pin, bush and roller are also analyzed based on scanning electron microscope. The results show that the main wear mechanism of automotive engine oil-pump chain is fatigue wear, and it's failure mechanism is the forming, extending and flaking of cracks on top layer of pin and bush. Pin and bush both occurred cycle-soften phenomenon, and roller occurred cycle-harden. Fretting wear is one of the most important "fall to pieces" failure causes of automotive chain. Ensuring sufficient strength and plasticity of roller, as well as adopting suitable shaping technology are the effective methods to increase its resistance to multi-cycle impact.展开更多
Modern automotive petrol engine performance is significantly affected by effective tune-up. Current practice of engine tune-up relies on the experience of the automotive engineer, and tune-up is usually done by trial-...Modern automotive petrol engine performance is significantly affected by effective tune-up. Current practice of engine tune-up relies on the experience of the automotive engineer, and tune-up is usually done by trial-and-error method and then the vehicle engine is run on the dynamometer to show the actual engine performance. Obviously the current practice involves a large amount of time and money, and then may even fail to tune up the engine optimally because a formal performance model of the engine has not been determined yet. With an emerging technique, Support Vector Machines (SVM), the approximate per- formance model of a petrol vehicle engine can be determined by training the sample engine performance data acquired from the dynamometer. The number of dynamometer tests for an engine tune-up can therefore be reduced because the estimated engine performance model can replace the dynamometer tests to a certain extent. In this paper, the construction, validation and accuracy of the model are discussed. The study showed that the predicted results agree well with the actual test results. To illustrate the significance of the SVM methodology, the results were also compared with that regressed using multilayer feedforward neural networks.展开更多
Application of CuO-water nanofluid with size of the nanoparticles of 20 nm and volume concentrations up 2% is numerically investigated in a radiator of Chevrolet Suburban diesel engine under turbulent flow conditions....Application of CuO-water nanofluid with size of the nanoparticles of 20 nm and volume concentrations up 2% is numerically investigated in a radiator of Chevrolet Suburban diesel engine under turbulent flow conditions. The heat transfer relations between airflow and nanofluid coolant have been obtained to evaluate local convective and overall heat transfer coefficients and also pumping power for nanofluid flowing in the radiator with a given heat exchange capacity. In the present study, the effects of the automotive speed and Reynolds number of the nanofluid in the different volume concentrations on the radiator performance are also investigated. The results show that for CuO-water nanofluid at 2% volume concentration circulating through the flat tubes with Renf = 6000 while the automotive speed is 70 km/hr, the overall heat transfer coefficient and pumping power are approximately 10% and 23.8% more than that of base fluid for given conditions, respectively.展开更多
The comprehensive promotion of the B&R has promised improved regional cooperation between Chinese oil and gas enterprises and Central Asia.Based on the cooperation patterns of Chinese oil and gas enterprises in Ce...The comprehensive promotion of the B&R has promised improved regional cooperation between Chinese oil and gas enterprises and Central Asia.Based on the cooperation patterns of Chinese oil and gas enterprises in Central Asia,this paper focuses on the business cooperation patterns,points out the strategic significance of such patterns in particular geography,and analyzes the prospects of such cooperation.Innovative optimization designs are developed,and innovative cooperation patterns are put forth based on the existing operation and cooperation patterns.By leveraging on the B&R,China's strategies concerning the energy of Central Asian areas shall be elevated,and an increasing number of energy enterprises will cooperate with Central Asia.展开更多
基金2024 Education and Teaching Reform Project of Hainan Tropical Ocean University(RHYxgnw2024-16)。
文摘This paper proposes teaching reforms in communication engineering majors,emphasizing the implementation of digital and adaptive teaching methodologies,integrating emerging technologies,breaking free from the constraints of traditional education,and fostering high-caliber talents.The reform measures encompass fundamental data collection,recognition of individual characteristics,recommendation of adaptive learning resources,process-oriented teaching management,adaptive student guidance and early warning systems,personalized evaluation,and the construction of an integrated service platform.These measures,when combined,form a comprehensive system that is expected to enhance teaching quality and efficiency,and facilitate student development.
文摘The environmental damage arising from the construction and engineering services was responsible for the appearance of several norms and resolutions regulating and directing the sector’s performance. In this article, we research how professionals with experience in public bids assess the difficulty degree of the implementation of those requirements and how they assess the environmental legislation regarding the protection and conservation of the environment, impact on costs, deadlines and the solution to environmental problems. The results show that industry professionals consider as “high” the level of difficulty to implement the addressed sustainability requirements, and that the Brazilian environmental legislation does not comply with its environmental protection role, increases the possibility of delays and costs of projects and services and hampers the emergence of solutions that could solve environmental problems.
文摘“Service Engineering”is a computer professional course with profound theory,extensive coverage and marked features of engineering.This article will analyze the characteristics of this course,the challenges we’ve encountered in the teaching process and a summary of our solutions.We hope that our work is helpful for other service engineering courses or similar courses.
基金supported by the National Key Research and Development Program of China(2021YFB2600405).
文摘In view of the problems of inconsistent data semantics,inconsistent data formats,and difficult data quality assurance between the railway engineering design phase and the construction and operation phase,as well as the difficulty in fully realizing the value of design results,this paper proposes a design and implementation scheme for a railway engineering collaborative design platform.The railway engineering collaborative design platform mainly includes functional modules such as metadata management,design collaboration,design delivery management,model component library,model rendering services,and Building Information Modeling(BIM)application services.Based on this,research is conducted on multi-disciplinary parameterized collaborative design technology for railway engineering,infrastructure data management and delivery technology,and design multi-source data fusion and application technology.The railway engineering collaborative design platform is compared with other railway design software to further validate its advantages and advanced features.The platform has been widely applied in multiple railway construction projects,greatly improving the design and project management efficiency.
文摘This paper first introduces the basic connotation of China’s whole-process engineering consulting.Immediately,analyze the organization model,service procurement model and charging standards of foreign whole-process engineering consulting(international terminology full-life cycle engineering consultant).Second,discuss the government’s role in the development of engineering consulting from two aspects:service management and market access.Finally,combined with the above analysis,the specific problems faced in the implementation process of the whole process engineering consulting are compared.Provide relevant suggestions on how companies and individuals respond to industry development trends.
文摘An approach to traffic engineering that uses differentiated services (DS) andmulti-protocol label switching (MPLS) to provide quantitative network quality of service (QoS)guarantees over an IP network was proposed. The traffic associated with assured forwarding (AF)Per-Hop behavior (PHB) in differentiated services enabled IP network was modeled. Furthermore, theeffect of such traffic on network resources with die objective of developing efficient trafficengineering methodologies was analyzed and the optimization problem relating to traffic engineeringin DS networks with an MPLS core was formulated. The service received by TCP and UDP flows when theyshare either a link or a MPLS traffic trunk was also compared and found that in order to benefitfrom traffic engineering, MPLS trunks should be implemented end-end (first router to last router).If some part of the network is MPLS trunk-unaware, the benefits are reduced or eliminated.
基金Support by Key Research and Development Project of Gansu Province(18YF1FA028)
文摘The ecosystem service value of Jingtaichuan electric power irrigation engineering( referred to as Jingdian engineering) was divided into internal value( the value of farmland system,shelter forest system outside of farmland and wetland waters) and external value( the ecological service value of ecological migration to the vegetation restoration of the Qilian Mountains) firstly,and then it was analyzed by using the model method and the factor equivalent method. The results showed that the internal ecological service value of Jingdian engineering was 36. 3 ×10~8 yuan,which was 25. 0 times larger than the total annual cost. The external ecological service value was 40. 05 ×10~8 yuan,which was 27. 6 times larger than the total annual cost. Among the three functional systems,the ecological service value of farmland system was the largest. The ecological service value of farmland system was mainly reflected in waste disposal,wind prevention and sand fixation,and food production. The external ecological service value was mainly the ecological service value of migration to vegetation restoration in the Qilian Mountains. Jingdian engineering is the only highlifting project that raises water to the desert in China. It transfers water from outer basins to control desertification and provides a successful road for ecological migration and desertification control in arid areas.
基金National High-Tech Research and De-velopment Program of China (863 Program) (No2004AA414010)Science Technology Project of Sichuan Province(No2006z03-015)
文摘To meet the actual requirements of an automotive industry chain collaboration platform (AICCP), this paper offers several simple but effective security policies based upon the traditional security mechanism of data transfer, including user ID verification with SOAP (simple object access protocol), header, SOAP message encryption with SOAP extension and XML (extensible markup language) file encryption and decryption. Application of these policies to the AICCP for more than one year proves the effectiveness of the data exchange practice between the AICCP and enterprise Intranet.
文摘Substantially lightweight brake discs with high wear resistance are highly desirable in the automotive industry.This paper presents an investigation of the precision-engineering design and development of automotive brake discs using nonhomogeneous Al/SiC metal-matrixcomposite materials.The design and development are based on modeling and analysis following stringent precision-engineering principles,i.e.,brake-disc systems that operate repeatably and stably over time as enabled by precision-engineering design.The design and development are further supported by tribological experimental testing and finite-element simulations.The results show the industrial feasibility of the innovative design approach and the application merits of using advanced metal-matrix-composite materials for next-generation automotive and electric vehicles.
文摘The research dealt with assessment of logistics service providers' capabilities in SECs (supporting subsea engineering companies) on the Tweneboa, Enyenra and Ntomme (TEN) project in Ghana. SECs need logistics service providers who offer consolidated services for project optimization and fulfillment of local content requirements of the project. Relevant Staffof7 SECs and 10 logistics service providers in Ghana formed part of the target group. The weighted scoring model was used in selecting a logistics service provider based on certain criteria. The selection criteria included Quality, Health, Safety and Environmental (QHSE) policies [Q], Compliance to regulations (GRA, Work permit, petroleum regulation) [C], Delivery of goods on time and response rate to deliver [D], Vessel, Cargo attendance and transportation (sea freight and air freight) [V], and Logistics (Personal logistics and Logistics base facilities) [L]. The study concluded Consolidated Shipping Agency (Conship) was the best Logistics Service Provider to offer the best consolidated services for project optimization under the TEN project.
基金supported by the POLOLAS project(TIN2016-76956-C3-2-R)of the Spanish Ministry of Economy and Competitiveness.
文摘In recent years, agile methodologies have been consolidated and extended in organizations that develop software in Web environments. For this reason, the development methodology of these organizations will not only be related to Services, but also to the Web Engineering paradigm. These organizations are heading for incorporating software development methodologies whose paradigm can allow integration, naturally and in the earlier stages of Web applications develop with the services of the organization that described and published in the Services Portfolio. The aim of this study will be to analyze the current state of the art in the process of discovering services in early stages of agile software development with focus on those identified requirements that could be covered with the services included in the Service Portfolio. We have identified 20 relevant papers through conducting a double systematic literature review (SLR). It is concluded that no study has been found that can solve the entire process of discovering candidate services within an organization that cover the requirements of a new application developed with agile methodologies. At the same time, guidelines have been found to formalize the solution to this problem and fill in that gap of knowledge by proposing in a single process, the formalization of a requirement based on agile techniques, which can be managed against a Services Portfolio.
基金sponsored by the US Government under Other Transaction number W15QKN-13-9-0001 between the Consortium for Energy, Environment and Demilitarization, and the Government, with funding provided by the US Army Engineer Research & Development Center
文摘Reducing heat accumulation within vehicles and ensuring appropriate vehicular temperature levels can lead to enhanced vehicle fuel economy,range,reliability,longevity,passenger comfort,and safety.Advancements in vehicle thermal management remain key as new technologies,consumer demand,societal concerns,and government regulations emerge and evolve.This study summarizes several recent advances in vehicle thermal management technology and modeling,with a focus on three key areas:the cabin,electronics,and exterior components of vehicles.Cabin-related topics covered include methods for reducing thermal loads and improving heating,ventilation,and air-conditioning(HVAC)systems;and advancements in window glazing/tinting and vehicle surface treatments.For the thermal management of electronics,including batteries and insulated-gate bipolar transistors(IGBTs),active and passive cooling methods that employ heat pipes,heat sinks,jet impingement,forced convection,and phase-change materials are discussed.Finally,efforts to model and enhance the heat transfer of exterior vehicular components are reviewed while considering drag/friction forces and environmental effects.Despite advances in the field of vehicle thermal management,challenges still exist;this article provides a broad summary of the major issues,with recommendations for further study.
基金This project is supported by National Innovation Foundation for TechnologyBased Firms, China (No.01C26213300872).
文摘The multi-impact characteristics and failure mechanism of two kinds of automotive engine chain made in China are studied through engine assembly and road-drive tests. The worn surface morphologies of rubbing area between pin, bush and roller are also analyzed based on scanning electron microscope. The results show that the main wear mechanism of automotive engine chain is fatigue wear, and its failure mechanism is the forming, extending and flaking of cracks on top layer of pin and bush. In addition, the material, hot-treatment method and shaping technique for roller have a great influence upon the resistance to multi-impact. Ensuring sufficient strength and plasticity of roller, as well as adopting suitable shaping technique are the effective method to increase its resistance to multi-impact.
基金This project is supported by National Innovation Foundation for Technology Based Firms, China (No. 01C26213300872)
文摘The high-speed multi-cycle impact and speed, load fluctuant characteristics of a kind of narrow-width automotive engine oil-pump chain 06BN-1 are studied through engine assembly and road-drive tests to satisfy the light-weight demand of engine. The worn surface morphologies of rubbing area between pin, bush and roller are also analyzed based on scanning electron microscope. The results show that the main wear mechanism of automotive engine oil-pump chain is fatigue wear, and it's failure mechanism is the forming, extending and flaking of cracks on top layer of pin and bush. Pin and bush both occurred cycle-soften phenomenon, and roller occurred cycle-harden. Fretting wear is one of the most important "fall to pieces" failure causes of automotive chain. Ensuring sufficient strength and plasticity of roller, as well as adopting suitable shaping technology are the effective methods to increase its resistance to multi-cycle impact.
文摘Modern automotive petrol engine performance is significantly affected by effective tune-up. Current practice of engine tune-up relies on the experience of the automotive engineer, and tune-up is usually done by trial-and-error method and then the vehicle engine is run on the dynamometer to show the actual engine performance. Obviously the current practice involves a large amount of time and money, and then may even fail to tune up the engine optimally because a formal performance model of the engine has not been determined yet. With an emerging technique, Support Vector Machines (SVM), the approximate per- formance model of a petrol vehicle engine can be determined by training the sample engine performance data acquired from the dynamometer. The number of dynamometer tests for an engine tune-up can therefore be reduced because the estimated engine performance model can replace the dynamometer tests to a certain extent. In this paper, the construction, validation and accuracy of the model are discussed. The study showed that the predicted results agree well with the actual test results. To illustrate the significance of the SVM methodology, the results were also compared with that regressed using multilayer feedforward neural networks.
文摘Application of CuO-water nanofluid with size of the nanoparticles of 20 nm and volume concentrations up 2% is numerically investigated in a radiator of Chevrolet Suburban diesel engine under turbulent flow conditions. The heat transfer relations between airflow and nanofluid coolant have been obtained to evaluate local convective and overall heat transfer coefficients and also pumping power for nanofluid flowing in the radiator with a given heat exchange capacity. In the present study, the effects of the automotive speed and Reynolds number of the nanofluid in the different volume concentrations on the radiator performance are also investigated. The results show that for CuO-water nanofluid at 2% volume concentration circulating through the flat tubes with Renf = 6000 while the automotive speed is 70 km/hr, the overall heat transfer coefficient and pumping power are approximately 10% and 23.8% more than that of base fluid for given conditions, respectively.
基金Innovation Research on the Model of Energy Cooperation modes between China and Central Asia under the Background of the “One Belt and One Road” Initiative,2018,National Social Science Fund of China(No:18XGJ001)Research on Sustainable Development of Sichuan’s National Gas Industry from Multiple Perspectives,2018,Soft Science Research Planned Project of Sichuan Province(No:2018ZR0072)
文摘The comprehensive promotion of the B&R has promised improved regional cooperation between Chinese oil and gas enterprises and Central Asia.Based on the cooperation patterns of Chinese oil and gas enterprises in Central Asia,this paper focuses on the business cooperation patterns,points out the strategic significance of such patterns in particular geography,and analyzes the prospects of such cooperation.Innovative optimization designs are developed,and innovative cooperation patterns are put forth based on the existing operation and cooperation patterns.By leveraging on the B&R,China's strategies concerning the energy of Central Asian areas shall be elevated,and an increasing number of energy enterprises will cooperate with Central Asia.