The aims of this study were to achieve working stability and continuity of the straw fibre extruder(D200)to improve the transportation efficiency of pretreated straw materials mulch film.Based on a theoretical analysi...The aims of this study were to achieve working stability and continuity of the straw fibre extruder(D200)to improve the transportation efficiency of pretreated straw materials mulch film.Based on a theoretical analysis of wheat straw friction characteristics and the mechanics model of wheat straw transport,a tilting variable-diameter spiral feeding device matched the designed straw fibre extruder(D200-type).Experimental researches were performed by using the orthogonal test method of the L16(45)to obtain the optimal parameter combination.The spiral angle,the speed of the screw shaft and the moisture content of straw raw materials were selected as influencing factors,and feeding efficiency was selected as the objective indicator.The results showed that the spiral angle,the rotating speed of screw shaft and the moisture content of straw raw materials had very significant effects on the feeding efficiency(p<0.01).The order of the extent of the influence of parameters on the feeding efficiency of wheat straw raw materials from high to low was the moisture content,the spiral angle and the speed of screw shaft.When the maximum transfer efficiency per unit time of the inclined spiral feeding device was 1040.8 kg·h-1,the spiral angle was 40?,the speed of screw shaft was 200 r·min-1 and the moisture content was 65%.Verification experiment proved the feasibility of straw fibre extruder designed.展开更多
Background A large amount of biomechanical and clinical evidence from previous studies suggest the efficiency of the two different posterior lumber non-fusion methods,interspinous distraction device （ISDD） and facet...Background A large amount of biomechanical and clinical evidence from previous studies suggest the efficiency of the two different posterior lumber non-fusion methods,interspinous distraction device （ISDD） and facet screw fixation system （FSS）,but the biomechanical comparison of ISDD and FSS has not been thoroughly clarified.Methods In the current study,finite element methods were used to investigate the biomechanical comparison of ISDD and FSS.The range of motion （ROM）,intradiscal pressure （IDP） and the protective effects gained by maintaining disc heights were evaluated.Results The ROM was similar between the two non-fusion methods under static standing,flexion and lateral bending.The FSS appeared to be more effective in resisting extension.At the implanted level L3/4,FSS displayed better results for maintaining and increasing posterior disc heights.At the L4/5 level in extension and lateral bending,FSS was better than ISDD,with comparable results observed in other motions.Comparing the posterior and lateral disc heights,FSS appeared to be more effective than ISDD.FSS also had a minor effect on the inferior adjacent segment than ISDD.FSS was more effective in reducing IDP than ISDD in extension.Conclusion Through the finite element analysis study,it can be seen that FSS demonstrates more beneficial biomechanical outcomes than does ISDD,such as being more effective in resisting extension,maintaining and increasing lumbar disc heights and reducing the inferior adjacent IDP in extension.展开更多
基金Supported by Integrated Research and Demonstration of Chemical Fertilizer and Pesticide Reduction Technology for Soybean in Northeast China(2018YFD0201004)Funding from the Construction of Modern Agricultural Industrial Technology System(GARS-04)。
文摘The aims of this study were to achieve working stability and continuity of the straw fibre extruder(D200)to improve the transportation efficiency of pretreated straw materials mulch film.Based on a theoretical analysis of wheat straw friction characteristics and the mechanics model of wheat straw transport,a tilting variable-diameter spiral feeding device matched the designed straw fibre extruder(D200-type).Experimental researches were performed by using the orthogonal test method of the L16(45)to obtain the optimal parameter combination.The spiral angle,the speed of the screw shaft and the moisture content of straw raw materials were selected as influencing factors,and feeding efficiency was selected as the objective indicator.The results showed that the spiral angle,the rotating speed of screw shaft and the moisture content of straw raw materials had very significant effects on the feeding efficiency(p<0.01).The order of the extent of the influence of parameters on the feeding efficiency of wheat straw raw materials from high to low was the moisture content,the spiral angle and the speed of screw shaft.When the maximum transfer efficiency per unit time of the inclined spiral feeding device was 1040.8 kg·h-1,the spiral angle was 40?,the speed of screw shaft was 200 r·min-1 and the moisture content was 65%.Verification experiment proved the feasibility of straw fibre extruder designed.
文摘Background A large amount of biomechanical and clinical evidence from previous studies suggest the efficiency of the two different posterior lumber non-fusion methods,interspinous distraction device （ISDD） and facet screw fixation system （FSS）,but the biomechanical comparison of ISDD and FSS has not been thoroughly clarified.Methods In the current study,finite element methods were used to investigate the biomechanical comparison of ISDD and FSS.The range of motion （ROM）,intradiscal pressure （IDP） and the protective effects gained by maintaining disc heights were evaluated.Results The ROM was similar between the two non-fusion methods under static standing,flexion and lateral bending.The FSS appeared to be more effective in resisting extension.At the implanted level L3/4,FSS displayed better results for maintaining and increasing posterior disc heights.At the L4/5 level in extension and lateral bending,FSS was better than ISDD,with comparable results observed in other motions.Comparing the posterior and lateral disc heights,FSS appeared to be more effective than ISDD.FSS also had a minor effect on the inferior adjacent segment than ISDD.FSS was more effective in reducing IDP than ISDD in extension.Conclusion Through the finite element analysis study,it can be seen that FSS demonstrates more beneficial biomechanical outcomes than does ISDD,such as being more effective in resisting extension,maintaining and increasing lumbar disc heights and reducing the inferior adjacent IDP in extension.
