The Silk Road originated in Chang＇an （Xi＇an today） and linked the land routes of countries from Transoxiana, the Persian Gulf, and the Mediterranean Sea. It is the trunk road over which China historically carried ...The Silk Road originated in Chang＇an （Xi＇an today） and linked the land routes of countries from Transoxiana, the Persian Gulf, and the Mediterranean Sea. It is the trunk road over which China historically carried out economic, trade, and cultural exchanges with Central Asia, West Asia, South Europe, and North Africa; the diligent and courageous people living in this region worked together with a friendship and cooperation that is still widely praised today.展开更多
Temperature-induced cracking during the construction of mass concrete is a significant concern.Numerical simulations of concrete temperature have primarily assumed that the concrete is placed in an open environment.Th...Temperature-induced cracking during the construction of mass concrete is a significant concern.Numerical simulations of concrete temperature have primarily assumed that the concrete is placed in an open environment.The problem of heat transfer between the air and concrete has been simplified to the concrete’s heat dissipation boundary.However,in the case of tubular concrete structures,where air inlet and outlet are relatively limited,the internal air temperature does not dissipate promptly to the external environment as it rises.To accurately simulate the temperature and creep stress in tubular concrete structures with enclosed air spaces during construction,we establish an air–concrete coupled heat transfer model according to the principles of conjugate heat transfer,and the accuracy of the model is verified through experiments.Furthermore,we conduct a case study to analyze the impact of airflow within the ship lock corridor on concrete temperature and creep stress.The results demonstrate that enhancing airflow within the corridor can significantly reduce the maximum concrete temperature.Compared with cases in which airflow within the corridor is neglected,the maximum concrete temperature and maximum tensile stress can be reduced by 12.5℃ and 0.7 MPa,respectively,under a wind speed of 4 m/s.The results of the traditional calculation method are relatively close to those obtained at a wind speed of 1 m/s.However,the temperature reduction process in the traditional method is faster,and the method yields greater tensile stress values for the corridor location.展开更多
The weldability of 12MnNiVR was examined in terms of the simulated HAZ continuous cooling transformation (SH-CCT) diagram,microstructure and mechanical properties of the simulated coarse grain heat-affected zone (CGHA...The weldability of 12MnNiVR was examined in terms of the simulated HAZ continuous cooling transformation (SH-CCT) diagram,microstructure and mechanical properties of the simulated coarse grain heat-affected zone (CGHAZ).When t 8/5 is shorter,the microstructure mainly consists of lath bainite.When t 8/5 is 60 s,the microstructure becomes coarser bainite.Some acicular ferrite appears beside lath bainite when t 8/5 =100s.Finally,a microstructure composed of polygonal ferrite,acicular ferrite,and small amount pearlite is obtained with a small amount of bainite at t 8/5 】100s.With the increase of t 8/5,the hardness of CGHAZ decreases considerably.The minimum impact toughness of CGHAZ appears at t 8/5 =100s.The hardness and the toughness of CGHAZ remain above the specified values for steel 12MnNiVR.展开更多
Mathematical physics equations are often utilized to describe physical phenomena in various fields of science and engineering.One such equation is the Fourier equation,which is a commonly used and effective method for...Mathematical physics equations are often utilized to describe physical phenomena in various fields of science and engineering.One such equation is the Fourier equation,which is a commonly used and effective method for evaluating the effectiveness of temperature control measures for mass concrete.One important measure for temperature control in mass concrete is the use of cooling water pipes.However,the mismatch of grids between large-scale concrete models and small-scale cooling pipe models can result in a significant waste of calculation time when using the finite element method.Moreover,the temperature of the water in the cooling pipe needs to be iteratively calculated during the thermal transfer process.The substructure method can effectively solve this problem,and it has been validated by scholars.The Abaqus/Python secondary development technology provides engineers with enough flexibility to combine the substructure method with an iteration algorithm,which enables the creation of a parametric modeling calculation for cooling water pipes.This paper proposes such a method,which involves iterating the water pipe boundary and establishing the water pipe unit substructure to numerically simulate the concrete temperature field that contains a cooling water pipe.To verify the feasibility and accuracy of the proposed method,two classic numerical examples were analyzed.The results showed that this method has good applicability in cooling pipe calculations.When the value of the iteration parameterαis 0.4,the boundary temperature of the cooling water pipes can meet the accuracy requirements after 4∼5 iterations,effectively improving the computational efficiency.Overall,this approach provides a useful tool for engineers to analyze the temperature control measures accurately and efficiently for mass concrete,such as cooling water pipes,using Abaqus/Python secondary development.展开更多
In 2015,the U.S National Institute of Standards and Technology(NIST)funded the Center of Excellence for Risk-Based Community Resilience Planning(CoE),a fourteen university-based consortium of almost 100 col-laborators...In 2015,the U.S National Institute of Standards and Technology(NIST)funded the Center of Excellence for Risk-Based Community Resilience Planning(CoE),a fourteen university-based consortium of almost 100 col-laborators,including faculty,students,post-doctoral scholars,and NIST researchers.This paper highlights the scientific theory behind the state-of-the-art cloud platform being developed by the CoE-the Interdisciplinary Networked Community Resilience Modeling Environment(IN-CORE).IN-CORE enables communities,consul-tants,and researchers to set up complex interdependent models of an entire community consisting of people,businesses,social institutions,buildings,transportation networks,water networks,and electric power networks and to predict their performance and recovery to hazard scenario events,including uncertainty propagation through the chained models.The modeling environment includes a detailed building inventory,hazard scenario models,building and infrastructure damage(fragility)and recovery functions,social science data-driven house-hold and business models,and computable general equilibrium(CGE)models of local economies.An important aspect of IN-CORE is the characterization of uncertainty and its propagation throughout the chained models of the platform.Three illustrative examples of community testbeds are presented that look at hazard impacts and recovery on population,economics,physical services,and social services.An overview of the IN-CORE technology and scientific implementation is described with a focus on four key community stability areas(CSA)that encompass an array of community resilience metrics(CRM)and support community resilience informed decision-making.Each testbed within IN-CORE has been developed by a team of engineers,social scientists,urban planners,and economists.Community models,begin with a community description,i.e.,people,businesses,buildings,infras-tructure,and progresses to the damage and loss of functions caused by a hazard scenario,i.e.,a flood,tornado,hurricane,or earthquake.Th展开更多
The problems of current highly redundant flight control system are analyzed in this paper. Our study gives methods of utilizing other information to reduce physical components on the condition of meeting the reliabili...The problems of current highly redundant flight control system are analyzed in this paper. Our study gives methods of utilizing other information to reduce physical components on the condition of meeting the reliability requirements for flight control system. The strategies presented in this paper mainly include information redundancy, multi-thread, time redundancy, geometry space redundancy, etc.. Analysis and simulation show these non-hardware based methods can reduce the requirement of system hardware level and thus reduce the system complexity, weight, space, costs and R＆D （research and development） time.展开更多
Given the strategic importance of energy and air pollution in the today world and due to the fact that the maritime transport system is one of the main sources of energy consumption and emissions in the environment, p...Given the strategic importance of energy and air pollution in the today world and due to the fact that the maritime transport system is one of the main sources of energy consumption and emissions in the environment, particularly contamination of water, so in recent years, fuel consumption and emissions reduction in the maritime transport industry has received considerable attention. Thus, in this paper, a new method is provided for typical boat hybridization, so by adding an electric motor and battery to boat power transmission system, dynamic performance will improve fuel consumption and emissions reduces. For this purpose, power transmission system elements are modelled and boat function is evaluated in real terms of movement by defining energy management strategy between power sources. The simulation results show that boat hybridization considerably reduces fuel consumption and emissions.展开更多
Ⅰ. AN OVERVIEW OF THE THIRD GEN-ERATION COMMAND AND CONTROL COMMUNICATIONS SYSTEM (CC3) OF THE HONG KONG POLICE FORCE1.1 CC1The first generation command and control communi-cations center of the HKPF (CC1) was establ...Ⅰ. AN OVERVIEW OF THE THIRD GEN-ERATION COMMAND AND CONTROL COMMUNICATIONS SYSTEM (CC3) OF THE HONG KONG POLICE FORCE1.1 CC1The first generation command and control communi-cations center of the HKPF (CC1) was established展开更多
This paper gives a brief introduction of IEC 62056 standards at first and then discusses the details about how to build the meter function model and the data model according to IEC 62056 standards.Finally it is descri...This paper gives a brief introduction of IEC 62056 standards at first and then discusses the details about how to build the meter function model and the data model according to IEC 62056 standards.Finally it is described how to realize the IEC 62056 electricity meter by a simulation instance.展开更多
Based on the background of navigation lock structure engineering in Changsha Integrated Hub, this study used Parametric Design Language （APDL） compilation command on the t＇mite element program ANSAYS platforms to s...Based on the background of navigation lock structure engineering in Changsha Integrated Hub, this study used Parametric Design Language （APDL） compilation command on the t＇mite element program ANSAYS platforms to simulate the temperature field of the layered pouring process about the lower lock head. The temperature contour map and the change laws of temperature field with time in each different levels of the floor were obtained. And compared with the actual instrument measurement data, the feasibility of the simulation analysis was concluded. Then, this study optimized the pouring process, obtained the suitable methods of layered pouring and put forward the measures to reduce the concrete temperature crack.展开更多
The effects of thickness-to-chord(t=c)ratio,anhedral angle(d),and cropping ratio from trailing-edge(Cr%)on the aerodynamics of non-slender reverse delta wings in comparison to non-slender delta wings with sweep angle ...The effects of thickness-to-chord(t=c)ratio,anhedral angle(d),and cropping ratio from trailing-edge(Cr%)on the aerodynamics of non-slender reverse delta wings in comparison to non-slender delta wings with sweep angle of 45°were characterized in a low-speed wind tunnel using force and pressure measurements.The measurements were conducted for total of 8 different delta and reverse delta wings.Two different t/c ratios of 5.9%and 1.1%,and two different anhedral angles ofd=15°and 30°for non-cropped and cropped at Cr=30%conditions were tested.The results indicate that the reverse delta wings generate higher lift-to-drag ratio and have better longitudinal static stability characteristics compared to the delta wings.The wing thickness has favorable effect on longitudinal static stability for the reverse delta wing whereas longitudinal static stability is not influenced by wing thickness for the delta wing.For reverse delta wings,the anhe-draled wing without cropping has adverse effect on aerodynamic performance and decreases the lift-to-drag ratio.Cropping in anhedraled wing causes significant improvement in lift-to-drag ratio,shift in aerodynamic and pressure centers towards the trailing-edge,and enhancement in longitudi-nal static stability.展开更多
Author analyzed the global background of low-carbon technology around the world,a technology & economy analysis model called TOS was developed in the paper,author analyzed technology paths for low-carbon Car in Ch...Author analyzed the global background of low-carbon technology around the world,a technology & economy analysis model called TOS was developed in the paper,author analyzed technology paths for low-carbon Car in China based on the current technologies available and technologies to be developed in China,3 possible paths are presented based on the analysis,author also explained the FAW BlueWay technology strategies for low carbon cars both for short mid and long term objectives.Author concludes the paper with illustration of powertrain lineup for FAW BlueWay Technologies.展开更多
In this paper,the influence of NaCl freeze-thaw(F-T)cycles and dry-wet(D-W)alternations on theflexural,com-pressive and bonding strengths of alkali-activatedfly ash(FA)and a blast furnace slag powder(BFS)is investi-gated...In this paper,the influence of NaCl freeze-thaw(F-T)cycles and dry-wet(D-W)alternations on theflexural,com-pressive and bonding strengths of alkali-activatedfly ash(FA)and a blast furnace slag powder(BFS)is investi-gated.The considered NaCl concentration is 3%.The effect of polypropylenefibers on the mechanical strengths is also examined.Scanning electron microscopy(SEM),thermogravimetry(TG)and X-ray diffraction(XRD)are selected to discern the mechanisms underpinning the NaCl-induced erosion.The obtained results indicate that the best results in terms of material resistance are obtained with admixtures containing 60%BFS and 40%FA in terms of mass ratio and 3%polypropylenefibers in terms of volume ratio.The maximum rates of decrease of theflexural,compressive and bonding strengths after 300 NaCl F-T cycles are 21.5%,20.3%and 22.6%,respec-tively.The corresponding rates of decrease due to NaCl D-W alternations are 28.1%,26.1%and 31.5%,respec-tively.The TG curves show that the alkali-activating activity of BFS is higher than that of FA.Moreover,in thefirst case,the microstructure of the hydration products is more compact.The results also show that NaCl F-T cycles lead to increasing cracks in the alkali-activated BFS.展开更多
China launched the policy of linking the increase in urban development land with the decrease in rural development land① in 2003. The paper focuses on two typical paths for implementation of the policy, i.e., exchang...China launched the policy of linking the increase in urban development land with the decrease in rural development land① in 2003. The paper focuses on two typical paths for implementation of the policy, i.e., exchanging homestead for urban housing, and "double exchanges." Based on a study on urbanization development, the paper analyzes the institutional innovation in the case of exchanging homestead for house in Huaming Town, as well as the jeopardization of "double exchanges," before summarizing the applicability of the "urban-rural land linking" policy. At the end, the paper emphasizes that in order to address the problems emerging during various kinds of urbanization, the linking policy should be carried out in accordance with local conditions and circumstances.展开更多
The Arizona Department of Transportation （ADOT） in the USA conducted a series of asphalt aging related research and special studies between the 1970s and 1990s. The studies covered over 157 test sections representin...The Arizona Department of Transportation （ADOT） in the USA conducted a series of asphalt aging related research and special studies between the 1970s and 1990s. The studies covered over 157 test sections representing both neat （virgin） asphalt and crumb rubber modified （asphalt-rubber） binders. The data comprised of a wide range of penetration, viscosity, and Performance Grade （PG） parameters, at original and aged conditions. In the late 1990s, asphalt PG complex shear modulus （G＊）, and phase angle （5） data were collected. The main purpose of this paper was to use the assembled database of the field core-aged asphalt test data and compare the test results to the American Association of State Highway and Transportation Officials approved Mechanistic-Empirical Pavement Design Guide （MEPDG） predictive modeled asphalt properties such as penetration and viscosity, G＊, and 5. Furthermore, G＊ and laboratory measurements on neat and asphalt-rubber binders extracted from the field cores of the pavement sections aged ten or more years were compared to the pressure aging vessel PG G＊ and ~. values. It was observed that the MEPDG predicted asphalt binder properties were rational for originally （tank） sampled binders, but fairly correlated for the aged binders. Additionally, penetration and viscosity aging indices representing over 20 years of field aged sections were established for a wide variety of asphalt binder grades. Overall, the relationships for aging indices were meaningful and rational. Results of this research indicated the degree of difficulty in predicting asphalt binder properties for pavements with ten or more years of field aging. The findings from this research study are envisioned to be of substantial value in future asphalt binder aging studies.展开更多
In modern physics and fabrication technology,simulation of projectile and target collision is vital to improve design in some critical applications,like;bulletproofing and medical applications.Graphene,the most promin...In modern physics and fabrication technology,simulation of projectile and target collision is vital to improve design in some critical applications,like;bulletproofing and medical applications.Graphene,the most prominent member of two dimensional materials presents ultrahigh tensile strength and stiffness.Moreover,polydimethylsiloxane(PDMS)is one of the most important elastomeric materials with a high extensive application area,ranging from medical,fabric,and interface material.In this work we considered graphene/PDMS structures to explore the bullet resistance of resulting nanocomposites.To this aim,extensive molecular dynamic simulations were carried out to identify the penetration of bullet through the graphene and PDMS composite structures.In this paper,we simulate the impact of a diamond bullet with different velocities on the composites made of single-or bi-layer graphene placed in different positions of PDMS polymers.The underlying mechanism concerning how the PDMS improves the resistance of graphene against impact loading is discussed.We discuss that with the same content of graphene,placing the graphene in between the PDMS result in enhanced bullet resistance.This work comparatively examines the enhancement in design of polymer nanocomposites to improve their bulletproofing response and the obtained results may serve as valuable guide for future experimental and theoretical studies.展开更多
Fushun Steel Plant is situated at thewestern part of Fushun city, Liaoning Pro-vince, 45 km from Shenyang. It is one ofthe major special steel plants in China.Established in 1937, Fushun Steel Planthas had a history ... Fushun Steel Plant is situated at thewestern part of Fushun city, Liaoning Pro-vince, 45 km from Shenyang. It is one ofthe major special steel plants in China.Established in 1937, Fushun Steel Planthas had a history of more than half century.Before 1948 it was a small-scale plant.From 1937 to 1948 the total steel productionwas only 58000 t. After foundation of PRCthere have been two stages of reconstruction;after the 1st stage (1958 to 1962) the plantbecame the first production base of su-peralloy and stainless steel in China: from1978 to 1983 (second stage) five sets oflarge advanced melting and hot workingequipment and ten sets of measurement展开更多
文摘The Silk Road originated in Chang＇an （Xi＇an today） and linked the land routes of countries from Transoxiana, the Persian Gulf, and the Mediterranean Sea. It is the trunk road over which China historically carried out economic, trade, and cultural exchanges with Central Asia, West Asia, South Europe, and North Africa; the diligent and courageous people living in this region worked together with a friendship and cooperation that is still widely praised today.
基金This work was supported by Construction Simulation and Support Optimization of Hydraulic Tunnel Based on Bonded Block-Synthetic Rock Mass Method and Hubei Province Postdoctoral Innovative Practice Position.
文摘Temperature-induced cracking during the construction of mass concrete is a significant concern.Numerical simulations of concrete temperature have primarily assumed that the concrete is placed in an open environment.The problem of heat transfer between the air and concrete has been simplified to the concrete’s heat dissipation boundary.However,in the case of tubular concrete structures,where air inlet and outlet are relatively limited,the internal air temperature does not dissipate promptly to the external environment as it rises.To accurately simulate the temperature and creep stress in tubular concrete structures with enclosed air spaces during construction,we establish an air–concrete coupled heat transfer model according to the principles of conjugate heat transfer,and the accuracy of the model is verified through experiments.Furthermore,we conduct a case study to analyze the impact of airflow within the ship lock corridor on concrete temperature and creep stress.The results demonstrate that enhancing airflow within the corridor can significantly reduce the maximum concrete temperature.Compared with cases in which airflow within the corridor is neglected,the maximum concrete temperature and maximum tensile stress can be reduced by 12.5℃ and 0.7 MPa,respectively,under a wind speed of 4 m/s.The results of the traditional calculation method are relatively close to those obtained at a wind speed of 1 m/s.However,the temperature reduction process in the traditional method is faster,and the method yields greater tensile stress values for the corridor location.
文摘The weldability of 12MnNiVR was examined in terms of the simulated HAZ continuous cooling transformation (SH-CCT) diagram,microstructure and mechanical properties of the simulated coarse grain heat-affected zone (CGHAZ).When t 8/5 is shorter,the microstructure mainly consists of lath bainite.When t 8/5 is 60 s,the microstructure becomes coarser bainite.Some acicular ferrite appears beside lath bainite when t 8/5 =100s.Finally,a microstructure composed of polygonal ferrite,acicular ferrite,and small amount pearlite is obtained with a small amount of bainite at t 8/5 】100s.With the increase of t 8/5,the hardness of CGHAZ decreases considerably.The minimum impact toughness of CGHAZ appears at t 8/5 =100s.The hardness and the toughness of CGHAZ remain above the specified values for steel 12MnNiVR.
文摘Mathematical physics equations are often utilized to describe physical phenomena in various fields of science and engineering.One such equation is the Fourier equation,which is a commonly used and effective method for evaluating the effectiveness of temperature control measures for mass concrete.One important measure for temperature control in mass concrete is the use of cooling water pipes.However,the mismatch of grids between large-scale concrete models and small-scale cooling pipe models can result in a significant waste of calculation time when using the finite element method.Moreover,the temperature of the water in the cooling pipe needs to be iteratively calculated during the thermal transfer process.The substructure method can effectively solve this problem,and it has been validated by scholars.The Abaqus/Python secondary development technology provides engineers with enough flexibility to combine the substructure method with an iteration algorithm,which enables the creation of a parametric modeling calculation for cooling water pipes.This paper proposes such a method,which involves iterating the water pipe boundary and establishing the water pipe unit substructure to numerically simulate the concrete temperature field that contains a cooling water pipe.To verify the feasibility and accuracy of the proposed method,two classic numerical examples were analyzed.The results showed that this method has good applicability in cooling pipe calculations.When the value of the iteration parameterαis 0.4,the boundary temperature of the cooling water pipes can meet the accuracy requirements after 4∼5 iterations,effectively improving the computational efficiency.Overall,this approach provides a useful tool for engineers to analyze the temperature control measures accurately and efficiently for mass concrete,such as cooling water pipes,using Abaqus/Python secondary development.
基金The Center for Risk-Based Community Resilience Planning is a NIST-funded Center of Excellencethe Center is funded through a cooperative agreement between the U.S.National Institute of Standards and Tech-nology and Colorado State University(NIST Financial Assistance Award Numbers:70NANB15H044 and 70NANB20H008)。
文摘In 2015,the U.S National Institute of Standards and Technology(NIST)funded the Center of Excellence for Risk-Based Community Resilience Planning(CoE),a fourteen university-based consortium of almost 100 col-laborators,including faculty,students,post-doctoral scholars,and NIST researchers.This paper highlights the scientific theory behind the state-of-the-art cloud platform being developed by the CoE-the Interdisciplinary Networked Community Resilience Modeling Environment(IN-CORE).IN-CORE enables communities,consul-tants,and researchers to set up complex interdependent models of an entire community consisting of people,businesses,social institutions,buildings,transportation networks,water networks,and electric power networks and to predict their performance and recovery to hazard scenario events,including uncertainty propagation through the chained models.The modeling environment includes a detailed building inventory,hazard scenario models,building and infrastructure damage(fragility)and recovery functions,social science data-driven house-hold and business models,and computable general equilibrium(CGE)models of local economies.An important aspect of IN-CORE is the characterization of uncertainty and its propagation throughout the chained models of the platform.Three illustrative examples of community testbeds are presented that look at hazard impacts and recovery on population,economics,physical services,and social services.An overview of the IN-CORE technology and scientific implementation is described with a focus on four key community stability areas(CSA)that encompass an array of community resilience metrics(CRM)and support community resilience informed decision-making.Each testbed within IN-CORE has been developed by a team of engineers,social scientists,urban planners,and economists.Community models,begin with a community description,i.e.,people,businesses,buildings,infras-tructure,and progresses to the damage and loss of functions caused by a hazard scenario,i.e.,a flood,tornado,hurricane,or earthquake.Th
文摘The problems of current highly redundant flight control system are analyzed in this paper. Our study gives methods of utilizing other information to reduce physical components on the condition of meeting the reliability requirements for flight control system. The strategies presented in this paper mainly include information redundancy, multi-thread, time redundancy, geometry space redundancy, etc.. Analysis and simulation show these non-hardware based methods can reduce the requirement of system hardware level and thus reduce the system complexity, weight, space, costs and R＆D （research and development） time.
文摘Given the strategic importance of energy and air pollution in the today world and due to the fact that the maritime transport system is one of the main sources of energy consumption and emissions in the environment, particularly contamination of water, so in recent years, fuel consumption and emissions reduction in the maritime transport industry has received considerable attention. Thus, in this paper, a new method is provided for typical boat hybridization, so by adding an electric motor and battery to boat power transmission system, dynamic performance will improve fuel consumption and emissions reduces. For this purpose, power transmission system elements are modelled and boat function is evaluated in real terms of movement by defining energy management strategy between power sources. The simulation results show that boat hybridization considerably reduces fuel consumption and emissions.
文摘Ⅰ. AN OVERVIEW OF THE THIRD GEN-ERATION COMMAND AND CONTROL COMMUNICATIONS SYSTEM (CC3) OF THE HONG KONG POLICE FORCE1.1 CC1The first generation command and control communi-cations center of the HKPF (CC1) was established
文摘This paper gives a brief introduction of IEC 62056 standards at first and then discusses the details about how to build the meter function model and the data model according to IEC 62056 standards.Finally it is described how to realize the IEC 62056 electricity meter by a simulation instance.
文摘Based on the background of navigation lock structure engineering in Changsha Integrated Hub, this study used Parametric Design Language （APDL） compilation command on the t＇mite element program ANSAYS platforms to simulate the temperature field of the layered pouring process about the lower lock head. The temperature contour map and the change laws of temperature field with time in each different levels of the floor were obtained. And compared with the actual instrument measurement data, the feasibility of the simulation analysis was concluded. Then, this study optimized the pouring process, obtained the suitable methods of layered pouring and put forward the measures to reduce the concrete temperature crack.
基金supported by Turkish Aerospace Industries,Inc.and Middle East Technical University(No.BAP TEZ-D-302-2021-10725).
文摘The effects of thickness-to-chord(t=c)ratio,anhedral angle(d),and cropping ratio from trailing-edge(Cr%)on the aerodynamics of non-slender reverse delta wings in comparison to non-slender delta wings with sweep angle of 45°were characterized in a low-speed wind tunnel using force and pressure measurements.The measurements were conducted for total of 8 different delta and reverse delta wings.Two different t/c ratios of 5.9%and 1.1%,and two different anhedral angles ofd=15°and 30°for non-cropped and cropped at Cr=30%conditions were tested.The results indicate that the reverse delta wings generate higher lift-to-drag ratio and have better longitudinal static stability characteristics compared to the delta wings.The wing thickness has favorable effect on longitudinal static stability for the reverse delta wing whereas longitudinal static stability is not influenced by wing thickness for the delta wing.For reverse delta wings,the anhe-draled wing without cropping has adverse effect on aerodynamic performance and decreases the lift-to-drag ratio.Cropping in anhedraled wing causes significant improvement in lift-to-drag ratio,shift in aerodynamic and pressure centers towards the trailing-edge,and enhancement in longitudi-nal static stability.
文摘Author analyzed the global background of low-carbon technology around the world,a technology & economy analysis model called TOS was developed in the paper,author analyzed technology paths for low-carbon Car in China based on the current technologies available and technologies to be developed in China,3 possible paths are presented based on the analysis,author also explained the FAW BlueWay technology strategies for low carbon cars both for short mid and long term objectives.Author concludes the paper with illustration of powertrain lineup for FAW BlueWay Technologies.
基金supported by 2023 University-Level Scientific Research Project of Ningbo Polytechnic(NZ23002)the First Batch of Ningbo Construction Scientific Research Projects in 2023(20230106).
文摘In this paper,the influence of NaCl freeze-thaw(F-T)cycles and dry-wet(D-W)alternations on theflexural,com-pressive and bonding strengths of alkali-activatedfly ash(FA)and a blast furnace slag powder(BFS)is investi-gated.The considered NaCl concentration is 3%.The effect of polypropylenefibers on the mechanical strengths is also examined.Scanning electron microscopy(SEM),thermogravimetry(TG)and X-ray diffraction(XRD)are selected to discern the mechanisms underpinning the NaCl-induced erosion.The obtained results indicate that the best results in terms of material resistance are obtained with admixtures containing 60%BFS and 40%FA in terms of mass ratio and 3%polypropylenefibers in terms of volume ratio.The maximum rates of decrease of theflexural,compressive and bonding strengths after 300 NaCl F-T cycles are 21.5%,20.3%and 22.6%,respec-tively.The corresponding rates of decrease due to NaCl D-W alternations are 28.1%,26.1%and 31.5%,respec-tively.The TG curves show that the alkali-activating activity of BFS is higher than that of FA.Moreover,in thefirst case,the microstructure of the hydration products is more compact.The results also show that NaCl F-T cycles lead to increasing cracks in the alkali-activated BFS.
文摘China launched the policy of linking the increase in urban development land with the decrease in rural development land① in 2003. The paper focuses on two typical paths for implementation of the policy, i.e., exchanging homestead for urban housing, and "double exchanges." Based on a study on urbanization development, the paper analyzes the institutional innovation in the case of exchanging homestead for house in Huaming Town, as well as the jeopardization of "double exchanges," before summarizing the applicability of the "urban-rural land linking" policy. At the end, the paper emphasizes that in order to address the problems emerging during various kinds of urbanization, the linking policy should be carried out in accordance with local conditions and circumstances.
文摘The Arizona Department of Transportation （ADOT） in the USA conducted a series of asphalt aging related research and special studies between the 1970s and 1990s. The studies covered over 157 test sections representing both neat （virgin） asphalt and crumb rubber modified （asphalt-rubber） binders. The data comprised of a wide range of penetration, viscosity, and Performance Grade （PG） parameters, at original and aged conditions. In the late 1990s, asphalt PG complex shear modulus （G＊）, and phase angle （5） data were collected. The main purpose of this paper was to use the assembled database of the field core-aged asphalt test data and compare the test results to the American Association of State Highway and Transportation Officials approved Mechanistic-Empirical Pavement Design Guide （MEPDG） predictive modeled asphalt properties such as penetration and viscosity, G＊, and 5. Furthermore, G＊ and laboratory measurements on neat and asphalt-rubber binders extracted from the field cores of the pavement sections aged ten or more years were compared to the pressure aging vessel PG G＊ and ~. values. It was observed that the MEPDG predicted asphalt binder properties were rational for originally （tank） sampled binders, but fairly correlated for the aged binders. Additionally, penetration and viscosity aging indices representing over 20 years of field aged sections were established for a wide variety of asphalt binder grades. Overall, the relationships for aging indices were meaningful and rational. Results of this research indicated the degree of difficulty in predicting asphalt binder properties for pavements with ten or more years of field aging. The findings from this research study are envisioned to be of substantial value in future asphalt binder aging studies.
基金B.M.and X.Z.appreciate the funding by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany’s Excellence Strategy within the Cluster of Excellence PhoenixD(EXC 2122,Project ID 390833453).
文摘In modern physics and fabrication technology,simulation of projectile and target collision is vital to improve design in some critical applications,like;bulletproofing and medical applications.Graphene,the most prominent member of two dimensional materials presents ultrahigh tensile strength and stiffness.Moreover,polydimethylsiloxane(PDMS)is one of the most important elastomeric materials with a high extensive application area,ranging from medical,fabric,and interface material.In this work we considered graphene/PDMS structures to explore the bullet resistance of resulting nanocomposites.To this aim,extensive molecular dynamic simulations were carried out to identify the penetration of bullet through the graphene and PDMS composite structures.In this paper,we simulate the impact of a diamond bullet with different velocities on the composites made of single-or bi-layer graphene placed in different positions of PDMS polymers.The underlying mechanism concerning how the PDMS improves the resistance of graphene against impact loading is discussed.We discuss that with the same content of graphene,placing the graphene in between the PDMS result in enhanced bullet resistance.This work comparatively examines the enhancement in design of polymer nanocomposites to improve their bulletproofing response and the obtained results may serve as valuable guide for future experimental and theoretical studies.
文摘 Fushun Steel Plant is situated at thewestern part of Fushun city, Liaoning Pro-vince, 45 km from Shenyang. It is one ofthe major special steel plants in China.Established in 1937, Fushun Steel Planthas had a history of more than half century.Before 1948 it was a small-scale plant.From 1937 to 1948 the total steel productionwas only 58000 t. After foundation of PRCthere have been two stages of reconstruction;after the 1st stage (1958 to 1962) the plantbecame the first production base of su-peralloy and stainless steel in China: from1978 to 1983 (second stage) five sets oflarge advanced melting and hot workingequipment and ten sets of measurement
