Due to a lack of technology,smaller breweries simply dump excess CO2 into the atmosphere,fueling the greenhouse effect and global warming.State-of-the-art CO2 capture technologies using nanofibrillated cellulose are e...Due to a lack of technology,smaller breweries simply dump excess CO2 into the atmosphere,fueling the greenhouse effect and global warming.State-of-the-art CO2 capture technologies using nanofibrillated cellulose are expensive and require laborious freeze-drying.Consequently,there is a high demand for affordable alternatives in order to reduce the environmental impact in this industry sector.This work describes a novel route for a quick and cost-efficient synthesis of amine-functionalized cellulose pellets by a surfactantassisted steam explosion process.Typical values with this method were porosity of 92%and density of 67 g/cm^3.Investigations on polyethylenimine(PEI)content and distribution revealed a maximum PEI concentration of 20 wt%with decreasing concentration to the core of a pellet.Sufficient stability against brewery exhaust gas was determined and CO2 release at^120℃ could be confirmed.Capacity tests under simulated working conditions with a novel laboratory reactor yielded a CO2 capacity of 1.0 mmol/g or 67 mol/m^3,which is comparable to values known from the literature for other cellulose-based adsorbents.展开更多
The high-gap plant protection machine is taken in this paper as the research object to ensure the good driving power and safety of the high-gap plant protection machine,and the control strategy of inter-shaft torque d...The high-gap plant protection machine is taken in this paper as the research object to ensure the good driving power and safety of the high-gap plant protection machine,and the control strategy of inter-shaft torque distribution is established under different working conditions to improve vehicle power and lateral stability.The anticipated demand torque is initially determined based on the structural characteristics and operational principles of the plant protection machine.Subsequently,a hierarchical control framework is devised by incorporating a formulated switching control strategy.Finally,a simulation model for torque distribution control strategy between shafts is developed on the Matlab/Simulink platform,followed by simulation and experimental verification.The results are presented as follows:the inter-shaft torque distribution strategy established in this paper increases the average longitudinal acceleration by 0.13 m/s^(2) and 0.14 m/s^(2) under the control of low and high to low adhesion road surfaces,respectively.Under the control of the single-line shifting condition,the yaw velocity can successfully follow the expected value with a maximum value of 0.61 rad/s.The side deflection angle of the center of mass does not exceed 2.8°,which can follow the ideal trajectory and improve power and safety.展开更多
The research on the self-propelled electric tiller is vital for further improving the quality and efficiency of greenhouse rotary tillage operation,reducing the work intensity and operation risk of operators,and achie...The research on the self-propelled electric tiller is vital for further improving the quality and efficiency of greenhouse rotary tillage operation,reducing the work intensity and operation risk of operators,and achieving environmentally friendly characteristics.Most of the existing self-propelled tillers rely on manual adjustment of the tillage depth.Moreover,the consistency and stability of the tillage depth are difficult to guarantee.In this study,the automatic control method of tillage depth of a self-propelled electric tiller is investigated.A method of applying the fuzzy PID(Proportional Integral Derivative)control method to the tillage depth adjustment system of a tiller is also proposed to realize automatic control.The system uses the real-time detection of the resistance sensor and angle sensor.The controller runs the electronically controlled hydraulic system to adjust the force and position comprehensively.The fuzzy control algorithm is used in the operation error control to realize the double-parameter control of the tillage depth.The simulation and experimental verification of the system are conducted.Results show that the control system applying fuzzy PID can improve the soil breaking rate by 3%in the operation process based on reducing the stability variation of tillage depth by 24%.The control strategy can reach the set value of tillage depth quickly and accurately.It can also meet the requirement of tillage depth consistency during the operation.展开更多
The machining surface integrity of aero-engine turbine disc slots has a significant impact on their fatigue life and service performance,and achieving efficiency and high-precision machining is still a great challenge...The machining surface integrity of aero-engine turbine disc slots has a significant impact on their fatigue life and service performance,and achieving efficiency and high-precision machining is still a great challenge.The high machining requirements of future aeroengine turbine disc slots will be difficult to satisfy using the broaching method.In addition,existing methods of slot machin-ing face difficulties in ensuring surface integrity.This study explored a cup shaped electroplated Cubic Boron Nitride(CBN)abrasive wheel for profile grinding the turbine disc slots of FGH96 powder metallurgy superalloy.The matrix structure of the cup shaped abrasive wheel was designed and verified.A profile grinding experiment was conducted for fir-tree slots on a five-axis machining center.The accuracy and the surface integrity were analyzed.Results show that the key dimension detection results of the slots were within the allowable tolerance range.Meanwhile,an average sur-face roughness Ra of 0.55μm was achieved,the residual stress was compressive,the plastic defor-mation layer thickness was less than 5μm,and the hardening layer thickness was less than 20μm.The research findings provide a new approach to machining the slots of aviation engine turbine discs and guidance for the high-quality processing of complex components.展开更多
Ultrasonic vibration-assisted grinding(UVAG)is an effective and promising method for machining of hard-to-cut materials.This article proposed an ultrasonic vibration plate device enabling the longitudinal full-wave an...Ultrasonic vibration-assisted grinding(UVAG)is an effective and promising method for machining of hard-to-cut materials.This article proposed an ultrasonic vibration plate device enabling the longitudinal full-wave and transverse half-wave(L2T1)vibration mode for UVAG.The characteristics of two-dimensional coupled vibration in different directions were analyzed on the basis of apparent elastic method and finite element method.Furthermore,a correction factor was applied to correct the frequency error caused by the apparent elastic method.Finally,the comparative experiments between the conventional creep-feed grinding and UVAG of Inconel 718 nickel-based superalloy were carried out.The results indicate that the apparent elastic method with the correction factor is accurate for the design of plate device under the L2T1 vibration mode.Compared with the conventional creep-feed grinding,the UVAG causes the reduction of grinding force and the improvement of machined surface quality of Inconel 718 nickel-based superalloy.Furthermore,under the current experimental conditions,the optimal ultrasonic vibration amplitude is determined as 6μm,with which the minimum surface roughness is achieved.展开更多
Residual stresses produced in polycrystalline CBN abrasive grits during a high-frequency induction brazing process are calculated by using ?nite element analysis, with a consideration of the nonuniform temperature dis...Residual stresses produced in polycrystalline CBN abrasive grits during a high-frequency induction brazing process are calculated by using ?nite element analysis, with a consideration of the nonuniform temperature distribution in the induction brazing model. The in?uences of induction brazing parameters on the residual stresses of polycrystalline CBN abrasive grits have been analyzed, including the embedding depth, grit side length, etc. Results obtained show that the tensile stress with a 40% embedding depth is 292 MPa, which is the minimum on the bonding interface compared with other embedding depths. Meanwhile, the maximum tensile stress is 575 MPa, with an increase of 59% compared with that of a grit side length of 50 mm. Finally, the simulation results of the brazing residual stress of polycrystalline CBN abrasive grits have been con?rmed valid based on the residual stress measurement of the brazed monocrystalline CBN grit.展开更多
In order to study the dynamic characteristics of hydro-mechanical continuously variable transmission(HMCVT)under ploughing and sowing conditions,a complete simulation model of HMCVT is established based on AMESim soft...In order to study the dynamic characteristics of hydro-mechanical continuously variable transmission(HMCVT)under ploughing and sowing conditions,a complete simulation model of HMCVT is established based on AMESim software,including mechanical transmission model,pump controlled hydraulic motor speed control model and section changing hydraulic system model.In addition,the dynamic model of tractor is established.In order to verify the correctness of the simulation model,a test-bed is established.The test of tractor running speed and the test of pump controlled hydraulic motor system were carried out on the test-bed.The test results show that the simulation model of pump control hydraulic system can correctly reflect the change of transmission ratio of pump controlled hydraulic motor,and the simulation model can reflect the actual working condition change of clutch.Thus,the correctness of the previous simulation model based on AMESim is verified.Based on the simulation model established by AMESim,the dynamic characteristics of HMCVT under ploughing and sowing conditions are studied.The results show that:Under ploughing condition,the planetary platoon will have strong impact at the moment of throttle opening and changing section.Under sowing condition,the HMCVT will have a great impact at the time of variable cross section,but the variation range of rodent force decreases and the changing trend tends to be stable.展开更多
文摘Due to a lack of technology,smaller breweries simply dump excess CO2 into the atmosphere,fueling the greenhouse effect and global warming.State-of-the-art CO2 capture technologies using nanofibrillated cellulose are expensive and require laborious freeze-drying.Consequently,there is a high demand for affordable alternatives in order to reduce the environmental impact in this industry sector.This work describes a novel route for a quick and cost-efficient synthesis of amine-functionalized cellulose pellets by a surfactantassisted steam explosion process.Typical values with this method were porosity of 92%and density of 67 g/cm^3.Investigations on polyethylenimine(PEI)content and distribution revealed a maximum PEI concentration of 20 wt%with decreasing concentration to the core of a pellet.Sufficient stability against brewery exhaust gas was determined and CO2 release at^120℃ could be confirmed.Capacity tests under simulated working conditions with a novel laboratory reactor yielded a CO2 capacity of 1.0 mmol/g or 67 mol/m^3,which is comparable to values known from the literature for other cellulose-based adsorbents.
基金The research is funded partially by the Agricultural Science and Technology Independent Innovation Fund of Jiangsu Province(Grant No.CX(22)3101)the National Key R&D Program(Grant No.2022YFD2001204)+1 种基金the International Science and Technology Cooperation Project of Jiangsu Province(Grant No.BZ2022002)the Natural Science Foundation of Jiangsu Province(Grant No.BK20210407).
文摘The high-gap plant protection machine is taken in this paper as the research object to ensure the good driving power and safety of the high-gap plant protection machine,and the control strategy of inter-shaft torque distribution is established under different working conditions to improve vehicle power and lateral stability.The anticipated demand torque is initially determined based on the structural characteristics and operational principles of the plant protection machine.Subsequently,a hierarchical control framework is devised by incorporating a formulated switching control strategy.Finally,a simulation model for torque distribution control strategy between shafts is developed on the Matlab/Simulink platform,followed by simulation and experimental verification.The results are presented as follows:the inter-shaft torque distribution strategy established in this paper increases the average longitudinal acceleration by 0.13 m/s^(2) and 0.14 m/s^(2) under the control of low and high to low adhesion road surfaces,respectively.Under the control of the single-line shifting condition,the yaw velocity can successfully follow the expected value with a maximum value of 0.61 rad/s.The side deflection angle of the center of mass does not exceed 2.8°,which can follow the ideal trajectory and improve power and safety.
基金the Agricultural Science and Technology Independent Innovation Fund of Jiangsu Province(CX(22)3101)State Key Research and development program(2022YFD2001204)the Modern Agricultural Machinery Equipment and Technology Promotion Project in Jiangsu Province(NJ2021-26).
文摘The research on the self-propelled electric tiller is vital for further improving the quality and efficiency of greenhouse rotary tillage operation,reducing the work intensity and operation risk of operators,and achieving environmentally friendly characteristics.Most of the existing self-propelled tillers rely on manual adjustment of the tillage depth.Moreover,the consistency and stability of the tillage depth are difficult to guarantee.In this study,the automatic control method of tillage depth of a self-propelled electric tiller is investigated.A method of applying the fuzzy PID(Proportional Integral Derivative)control method to the tillage depth adjustment system of a tiller is also proposed to realize automatic control.The system uses the real-time detection of the resistance sensor and angle sensor.The controller runs the electronically controlled hydraulic system to adjust the force and position comprehensively.The fuzzy control algorithm is used in the operation error control to realize the double-parameter control of the tillage depth.The simulation and experimental verification of the system are conducted.Results show that the control system applying fuzzy PID can improve the soil breaking rate by 3%in the operation process based on reducing the stability variation of tillage depth by 24%.The control strategy can reach the set value of tillage depth quickly and accurately.It can also meet the requirement of tillage depth consistency during the operation.
基金supported by the National Natural Science Foundation of China (Nos.52305477,52375447,52305474)Major Special Projects of Aero-engine and Gas Turbine (No.2017-VII-0002-0095)+4 种基金the Special Fund of Taishan Scholars Project (No.tsqn202211179)the Youth Talent Promotion Project in Shandong (No.SDAST2021qt12)the Natural Science Foundation of Shandong Province (Nos.ZR2023QE057,ZR2022QE028,ZR2021QE116,and ZR2020KE027)Qingdao Science and Technology Planning Park Cultivation Plan (No.23-1-5-yqpy-17-qy)the Natural Science Foundation of Jiangsu Province (No.BK20210407).
文摘The machining surface integrity of aero-engine turbine disc slots has a significant impact on their fatigue life and service performance,and achieving efficiency and high-precision machining is still a great challenge.The high machining requirements of future aeroengine turbine disc slots will be difficult to satisfy using the broaching method.In addition,existing methods of slot machin-ing face difficulties in ensuring surface integrity.This study explored a cup shaped electroplated Cubic Boron Nitride(CBN)abrasive wheel for profile grinding the turbine disc slots of FGH96 powder metallurgy superalloy.The matrix structure of the cup shaped abrasive wheel was designed and verified.A profile grinding experiment was conducted for fir-tree slots on a five-axis machining center.The accuracy and the surface integrity were analyzed.Results show that the key dimension detection results of the slots were within the allowable tolerance range.Meanwhile,an average sur-face roughness Ra of 0.55μm was achieved,the residual stress was compressive,the plastic defor-mation layer thickness was less than 5μm,and the hardening layer thickness was less than 20μm.The research findings provide a new approach to machining the slots of aviation engine turbine discs and guidance for the high-quality processing of complex components.
基金financially supported by the National Natural Science Foundation of China(Nos.51921003 and 51775275)National Key Laboratory of Science and Technology on Helicopter Transmission(Nanjing University of Aeronautics and Astronautics)(No.HTL-A-20G01)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX20_0179)。
文摘Ultrasonic vibration-assisted grinding(UVAG)is an effective and promising method for machining of hard-to-cut materials.This article proposed an ultrasonic vibration plate device enabling the longitudinal full-wave and transverse half-wave(L2T1)vibration mode for UVAG.The characteristics of two-dimensional coupled vibration in different directions were analyzed on the basis of apparent elastic method and finite element method.Furthermore,a correction factor was applied to correct the frequency error caused by the apparent elastic method.Finally,the comparative experiments between the conventional creep-feed grinding and UVAG of Inconel 718 nickel-based superalloy were carried out.The results indicate that the apparent elastic method with the correction factor is accurate for the design of plate device under the L2T1 vibration mode.Compared with the conventional creep-feed grinding,the UVAG causes the reduction of grinding force and the improvement of machined surface quality of Inconel 718 nickel-based superalloy.Furthermore,under the current experimental conditions,the optimal ultrasonic vibration amplitude is determined as 6μm,with which the minimum surface roughness is achieved.
基金supported by the National Natural Science Foundation of China(No.51775275)the Fundamental Research Funds for the Central Universities(No.NE2014103 and No.NZ2016107)
文摘Residual stresses produced in polycrystalline CBN abrasive grits during a high-frequency induction brazing process are calculated by using ?nite element analysis, with a consideration of the nonuniform temperature distribution in the induction brazing model. The in?uences of induction brazing parameters on the residual stresses of polycrystalline CBN abrasive grits have been analyzed, including the embedding depth, grit side length, etc. Results obtained show that the tensile stress with a 40% embedding depth is 292 MPa, which is the minimum on the bonding interface compared with other embedding depths. Meanwhile, the maximum tensile stress is 575 MPa, with an increase of 59% compared with that of a grit side length of 50 mm. Finally, the simulation results of the brazing residual stress of polycrystalline CBN abrasive grits have been con?rmed valid based on the residual stress measurement of the brazed monocrystalline CBN grit.
基金The research is funded partially by the Jiangsu International Cooperation Project(Grant No.BZ2021007)the Modern Agricultural Machinery Equipment and Technology Promotion Project in Jiangsu Province(Grant No.NJ2021-06)+2 种基金the Nanjing International Science and Technology Cooperation Project(Grant No.202002049)the Xuzhou key research and development projects(Grant No.KC21136)The Fundamental Research Funds for the Central Universities(Grant No.KYGD202105).
文摘In order to study the dynamic characteristics of hydro-mechanical continuously variable transmission(HMCVT)under ploughing and sowing conditions,a complete simulation model of HMCVT is established based on AMESim software,including mechanical transmission model,pump controlled hydraulic motor speed control model and section changing hydraulic system model.In addition,the dynamic model of tractor is established.In order to verify the correctness of the simulation model,a test-bed is established.The test of tractor running speed and the test of pump controlled hydraulic motor system were carried out on the test-bed.The test results show that the simulation model of pump control hydraulic system can correctly reflect the change of transmission ratio of pump controlled hydraulic motor,and the simulation model can reflect the actual working condition change of clutch.Thus,the correctness of the previous simulation model based on AMESim is verified.Based on the simulation model established by AMESim,the dynamic characteristics of HMCVT under ploughing and sowing conditions are studied.The results show that:Under ploughing condition,the planetary platoon will have strong impact at the moment of throttle opening and changing section.Under sowing condition,the HMCVT will have a great impact at the time of variable cross section,but the variation range of rodent force decreases and the changing trend tends to be stable.