An objective evaluation scheme for automotive technical and comprehensive performance could provide critical and instructive insights for academic research,engineering practice,and commercial marketing of vehicles.In ...An objective evaluation scheme for automotive technical and comprehensive performance could provide critical and instructive insights for academic research,engineering practice,and commercial marketing of vehicles.In this paper,the technical performance index A=S∕T_(1)⋅T_(2)(m∕(s^(2)⋅L))and comprehensive performance index F=M⋅S∕T_(1)⋅T_(2),(kN⋅L^(−1),where M is the vehicle mass)are formulated by incorporating the vehicle 0–100 km⋅h^(−1) acceleration duration T_(1),100–0 km⋅h^(−1) braking duration T_(2),and fuel economy S(mileage per liter fuel at constant speed)to assess the vehicle’s longitudinal dynamic performance.A and F offer a clear physical implication of a vehicle’s acceleration capability and traction efficiency acquired per unit of fuel consumption,respectively.These indexes are used for wide case studies of popular market sedans and SUVs of joint ventures(JVs)and domestic brands in China over the last 17 years.The findings prove that this approach could be effectively and reliably utilized for the objective evaluation and analysis of the technical and comprehensive performance of automotive models.展开更多
The study evaluated the effects of a diet incorporating a mango-based feed on the technical-economic performance of milk production of Montbeliard cows at the end of lactation in a dairy farm in Bobo-Dioulasso, Burkin...The study evaluated the effects of a diet incorporating a mango-based feed on the technical-economic performance of milk production of Montbeliard cows at the end of lactation in a dairy farm in Bobo-Dioulasso, Burkina Faso. To do so, 14 cows were subjected to 3 diets, including an experimental diet incorporating mango (ED) in comparison to a balanced control diet (BCD) and to the feeding practice of the farmer (FCD) during 60 days. Results show that the average amount of milk milked per day from ED (10.93 ± 0.17 L) was significantly higher (p < 0.05) than BCD (8.80 ± 0.19 L) and RTA (5.39 ± 0.14 L). The conversion index of FPD (4.24 ± 0.14) was significantly higher (p < 0.05) than that of BCD (1.75 ± 0.19) and ED (1.26 ± 0.16). Average feed costs per liter of milk (FC/L) were significantly different (p (125.95 ± 4.56 FCFA), BCD (83.67 ± 6.36 FCFA) and ED (60.06 ± 5.49 FCFA). The average gross profit margins (GPM) were significantly higher and decreasing (p ,953 ± 5031 FCFA), BCD (167,157 ± 5831 FCFA) and FCD (74,188 ± 4185 FCFA). Mango feed can be used in the diet of dairy cows. Its use contributes to the reduction of production costs and the generation of substantial profits. The valorization of mango residues is an alternative for a greater availability of feed at lower cost for the animals. It could contribute to a better management of processing residues that pollute the environment and to the reduction of fruit flies that affect orchard yields through reinfestation. The increased use of mango in dairy cattle feed should be encouraged.展开更多
The use of renewable energy is essential for addressing global climate change,and offshore wind power plays a critical role in achieving this goal.As nearshore resources become saturated,the focus of offshore wind pow...The use of renewable energy is essential for addressing global climate change,and offshore wind power plays a critical role in achieving this goal.As nearshore resources become saturated,the focus of offshore wind power development is shifting to deep-sea areas.Deep-sea wind power transmission schemes must prioritize lightweight designs and low costs to enhance overall economic and technical feasibility.Currently,four lightweight offshore wind power transmission schemes have been identified:low-frequency alternating current(LFAC)transmission,high-voltage direct current(HVDC)transmission utilizing uncontrolled diode rectifier units(DRU-HVDC),DRU-MMC parallel-connection hybrid rectifier transmission(PCDRU-MMC),and DRU-MMC series-connection hybrid rectifier transmission(SCDRU-MMC).Four schemesare examined,advantages and disadvantages in various scenariosare outlined,technical performanceare analyzed.A comprehensive economic assessment of each scheme is conducted for deep-sea environments far from load centers.The results indicate that LFAC transmission effectively reduces transmission losses,whereas DRU-HVDC has limitations in terms of voltage support and black-start capability.In contrast,hybrid rectification solutions such as PCDRU-MMC and SCDRU-MMC combine the economic benefits of DRU-HVDC with the flexibility of modular multilevel converters(MMCs),thereby enhancing system reliability and efficiency.展开更多
This paper focuses on investigations encompassing comparative assessment of gasturbine cycle options.More specifically,investigation was caried out of technical performanceof turboshaft engine cycles based on existing...This paper focuses on investigations encompassing comparative assessment of gasturbine cycle options.More specifically,investigation was caried out of technical performanceof turboshaft engine cycles based on existing simple cycle(SC)and its projected modifiedcycles for civil helicopter application.Technically,thermal efficiency,specific fuel consump-tion,and power output are of paramount importance to the overall performance of gas urbineengines.In course of carrying out this research,turbomatch software established at CranfieldUniversity based on gas turbine theory was applied to conduct simulation of a simple cycle(baseline)two-spool helicopter turboshaft engine model with free power turbine.Similarly,some modified gas urbine cycle configurations incoporating unconventional components,such as engine cycle with low pressure compressor(LPC)zero-staged,recuperated enginecycle,and intercooled/recuperated(ICR)engine cycle,were also simulated.In doing so,designpoint(DP)and off-design point(OD)performances of the engine models were established.Thepercentage changes in performance parameters of the modified cycle engines over the simplecycle were evaluated and it was found that to a large extent,the modified engine cycles withunconventional components exhibit better performances in terms of thermal efficiency andspecific fuel consumption than the traditional simple cycle engine.This research made use ofpublic domain open source references.展开更多
基金The National Natural Science Foundation of China(Project Name:Transmission mechanics and performance optimization of confined granular media self-adaptive differentialNo.51475475)工+1 种基金the Changsha Natural Science Foundation of China(Project Name:Structure principle and performance prediction of the intelligent tireNo.kq2014130)have provided funding for this research.
文摘An objective evaluation scheme for automotive technical and comprehensive performance could provide critical and instructive insights for academic research,engineering practice,and commercial marketing of vehicles.In this paper,the technical performance index A=S∕T_(1)⋅T_(2)(m∕(s^(2)⋅L))and comprehensive performance index F=M⋅S∕T_(1)⋅T_(2),(kN⋅L^(−1),where M is the vehicle mass)are formulated by incorporating the vehicle 0–100 km⋅h^(−1) acceleration duration T_(1),100–0 km⋅h^(−1) braking duration T_(2),and fuel economy S(mileage per liter fuel at constant speed)to assess the vehicle’s longitudinal dynamic performance.A and F offer a clear physical implication of a vehicle’s acceleration capability and traction efficiency acquired per unit of fuel consumption,respectively.These indexes are used for wide case studies of popular market sedans and SUVs of joint ventures(JVs)and domestic brands in China over the last 17 years.The findings prove that this approach could be effectively and reliably utilized for the objective evaluation and analysis of the technical and comprehensive performance of automotive models.
文摘The study evaluated the effects of a diet incorporating a mango-based feed on the technical-economic performance of milk production of Montbeliard cows at the end of lactation in a dairy farm in Bobo-Dioulasso, Burkina Faso. To do so, 14 cows were subjected to 3 diets, including an experimental diet incorporating mango (ED) in comparison to a balanced control diet (BCD) and to the feeding practice of the farmer (FCD) during 60 days. Results show that the average amount of milk milked per day from ED (10.93 ± 0.17 L) was significantly higher (p < 0.05) than BCD (8.80 ± 0.19 L) and RTA (5.39 ± 0.14 L). The conversion index of FPD (4.24 ± 0.14) was significantly higher (p < 0.05) than that of BCD (1.75 ± 0.19) and ED (1.26 ± 0.16). Average feed costs per liter of milk (FC/L) were significantly different (p (125.95 ± 4.56 FCFA), BCD (83.67 ± 6.36 FCFA) and ED (60.06 ± 5.49 FCFA). The average gross profit margins (GPM) were significantly higher and decreasing (p ,953 ± 5031 FCFA), BCD (167,157 ± 5831 FCFA) and FCD (74,188 ± 4185 FCFA). Mango feed can be used in the diet of dairy cows. Its use contributes to the reduction of production costs and the generation of substantial profits. The valorization of mango residues is an alternative for a greater availability of feed at lower cost for the animals. It could contribute to a better management of processing residues that pollute the environment and to the reduction of fruit flies that affect orchard yields through reinfestation. The increased use of mango in dairy cattle feed should be encouraged.
基金Supported by the Science and Technology Project of China Southern Power Grid Corporation(030000KC23040118).
文摘The use of renewable energy is essential for addressing global climate change,and offshore wind power plays a critical role in achieving this goal.As nearshore resources become saturated,the focus of offshore wind power development is shifting to deep-sea areas.Deep-sea wind power transmission schemes must prioritize lightweight designs and low costs to enhance overall economic and technical feasibility.Currently,four lightweight offshore wind power transmission schemes have been identified:low-frequency alternating current(LFAC)transmission,high-voltage direct current(HVDC)transmission utilizing uncontrolled diode rectifier units(DRU-HVDC),DRU-MMC parallel-connection hybrid rectifier transmission(PCDRU-MMC),and DRU-MMC series-connection hybrid rectifier transmission(SCDRU-MMC).Four schemesare examined,advantages and disadvantages in various scenariosare outlined,technical performanceare analyzed.A comprehensive economic assessment of each scheme is conducted for deep-sea environments far from load centers.The results indicate that LFAC transmission effectively reduces transmission losses,whereas DRU-HVDC has limitations in terms of voltage support and black-start capability.In contrast,hybrid rectification solutions such as PCDRU-MMC and SCDRU-MMC combine the economic benefits of DRU-HVDC with the flexibility of modular multilevel converters(MMCs),thereby enhancing system reliability and efficiency.
文摘This paper focuses on investigations encompassing comparative assessment of gasturbine cycle options.More specifically,investigation was caried out of technical performanceof turboshaft engine cycles based on existing simple cycle(SC)and its projected modifiedcycles for civil helicopter application.Technically,thermal efficiency,specific fuel consump-tion,and power output are of paramount importance to the overall performance of gas urbineengines.In course of carrying out this research,turbomatch software established at CranfieldUniversity based on gas turbine theory was applied to conduct simulation of a simple cycle(baseline)two-spool helicopter turboshaft engine model with free power turbine.Similarly,some modified gas urbine cycle configurations incoporating unconventional components,such as engine cycle with low pressure compressor(LPC)zero-staged,recuperated enginecycle,and intercooled/recuperated(ICR)engine cycle,were also simulated.In doing so,designpoint(DP)and off-design point(OD)performances of the engine models were established.Thepercentage changes in performance parameters of the modified cycle engines over the simplecycle were evaluated and it was found that to a large extent,the modified engine cycles withunconventional components exhibit better performances in terms of thermal efficiency andspecific fuel consumption than the traditional simple cycle engine.This research made use ofpublic domain open source references.
