Rice straw is a rice by-product, which is currently mostly wasted in Vietnam, in particular in the Mekong delta. At present, the cost of straw gathering is increasing because of the increased use of combine harvesters...Rice straw is a rice by-product, which is currently mostly wasted in Vietnam, in particular in the Mekong delta. At present, the cost of straw gathering is increasing because of the increased use of combine harvesters. High labor cost and lack of labor makes manual collection unfeasible. Farmers therefore often just burn it, which causes pollution, increased greenhouse gas emissions and loss of opportunities to value add. An economic and environmental evaluation and technical field testing of a straw baler with 4 ha/day capacity was therefore conducted in Long An province. During the field testing data on the gathering capacity, fuel consumption, labor requirement and other cost items were collected. The test results showed that the baling cost is US$19.0 per ton of rice straw, the pay-back period of 2. 1 years and the internal rate of return of 38%. In addition to the baling cost, the transportation cost varies from US$24 for a distance of 100 km to US$32 for 150 km. The benefits of the machine are not only economical but also include the reduction of field burning.展开更多
The electrocatalytic synthesis of urea(ESU)is a green and sustainable alternative to conventional production methods,and the related research is still in its infancy.Up to now,the field has been explored by several re...The electrocatalytic synthesis of urea(ESU)is a green and sustainable alternative to conventional production methods,and the related research is still in its infancy.Up to now,the field has been explored by several reviews,however,the authors are focusing on some particular problems and could not provide a holistic view of the ESU.Based on these considerations,the novelty of this review lies in its comprehensive and systematic framework,as well as its in-depth analysis and general summary of several key issues.Hence,in this review,we critically evaluated the ESU through in-depth studies of various aspects,including nitrogen sources,catalysts choice,conditions modifications,detection methods,product calculations,and mechanisms evaluation,etc.In addition,after analyzing the reaction routes,reaction kinetics/thermodynamics and techno-economics assessment are also investigated.Finally,the summary and outlook are presented eventually,providing valuable insights for the related research.We believe that we will provide researchers with a comprehensive and clear picture of green synthesized urea,which is of great academic and practical significance.展开更多
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
文摘Rice straw is a rice by-product, which is currently mostly wasted in Vietnam, in particular in the Mekong delta. At present, the cost of straw gathering is increasing because of the increased use of combine harvesters. High labor cost and lack of labor makes manual collection unfeasible. Farmers therefore often just burn it, which causes pollution, increased greenhouse gas emissions and loss of opportunities to value add. An economic and environmental evaluation and technical field testing of a straw baler with 4 ha/day capacity was therefore conducted in Long An province. During the field testing data on the gathering capacity, fuel consumption, labor requirement and other cost items were collected. The test results showed that the baling cost is US$19.0 per ton of rice straw, the pay-back period of 2. 1 years and the internal rate of return of 38%. In addition to the baling cost, the transportation cost varies from US$24 for a distance of 100 km to US$32 for 150 km. The benefits of the machine are not only economical but also include the reduction of field burning.
基金supported financially by the National Natural Science Foundation of China(No.22066006)Guizhou Province Science and Technology Projects(Foundation-ZK[2022]Key 012).
文摘The electrocatalytic synthesis of urea(ESU)is a green and sustainable alternative to conventional production methods,and the related research is still in its infancy.Up to now,the field has been explored by several reviews,however,the authors are focusing on some particular problems and could not provide a holistic view of the ESU.Based on these considerations,the novelty of this review lies in its comprehensive and systematic framework,as well as its in-depth analysis and general summary of several key issues.Hence,in this review,we critically evaluated the ESU through in-depth studies of various aspects,including nitrogen sources,catalysts choice,conditions modifications,detection methods,product calculations,and mechanisms evaluation,etc.In addition,after analyzing the reaction routes,reaction kinetics/thermodynamics and techno-economics assessment are also investigated.Finally,the summary and outlook are presented eventually,providing valuable insights for the related research.We believe that we will provide researchers with a comprehensive and clear picture of green synthesized urea,which is of great academic and practical significance.
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.
