Aiming at the discontinuous traction on contact elements of roller bearing,new concepts of sub- and micro-element are put forward. In the sub-element and micro-element,traction influence coefficient has been modified,...Aiming at the discontinuous traction on contact elements of roller bearing,new concepts of sub- and micro-element are put forward. In the sub-element and micro-element,traction influence coefficient has been modified, which is calculated by the former boundary elementmethod (BEM) with roller bearing load. Hence, three-dimensional distribution of load on rollerbearing is calculated accurately. In practice, it has been proved that this method has highercalculation accuracy. An effective numerical method is offered for analyzing load characteristics ofroller bearing to improve service longevity of roller bearing and operation efficiency of rollingmill.展开更多
Micro-nutrient deficiency in soil results in crop yield loss and poor seed quality. Correcting this deficiency is normally done by foliar or soil application. The objective of this research was to determine the effect...Micro-nutrient deficiency in soil results in crop yield loss and poor seed quality. Correcting this deficiency is normally done by foliar or soil application. The objective of this research was to determine the effects of soil applications of five micro-nutrients (Mn, Cu, Zn, Mo, and B) alone and in combination with a chelating agent citric acid (CA) on soybean leaf and seed nutrients. Source of micro-nutrient compounds were MnCl2, CuCl2, ZnCl2, MoO3, and H3BO3. Our hypothesis was that micro-and macro-nutrients may be transported to leaves and then to seeds at different rates. They may interact synergistically or competitively during the uptake process. A greenhouse experiment was conducted at Mississippi Valley State University, Itta Bena, Mississippi, USA. Soybean cultivar, Bolivar (maturity group V), was applied with micro-nutrients-chelating agent citric acid at V3 and R3 (pod initiation) stage. The results showed that applications of Cu, Zn, B and Mo increased three unrolled trifoliate leaves Cu, Zn, B by 26.5%, 13.8%, 113% and Mo increased to 179 mg/kg, respectively in the leaves. Also, the application of “Cu, Zn, B and Mo increased Cu, Zn, B by 55.5%, 8.2%, 28.6% and Mo increased to 202 mg/kg” respectively in soybean seeds. Application of Mn had no direct effect on increasing Mn either in leaves or in seeds, however, Mn and Mn + CA treatment affected other mineral contents. Application of Cu, Zn, Mo, B and CA increased macro-nutrients K, N, P, Mg, and S. Irrespective of the applications, the nutrient increase trend in seed was Na > Fe > Zn > Mn > B > Cu > Mo. However, Mo application resulted in the following seed nutrient accumulation pattern: Na > Mo > Fe > Zn > Mn > B > Cu. This may suggest that Mo had higher mobility to seeds than other micro-nutrients. Combination of soil application of Mo + CA increased Mo in leaves at V3 stage;however, Mo + CA soil application during pod-filling stage had no significant effects on Mo accumulation in seeds. The current research showed that some micro-nutrient application with the chelating agent CA could increase seed nutrients. Since these results are conducted under greenhouse experiments, further research under field conditions is needed before conclusive recommendations are made.展开更多
Studies on the availability of plant nutrients in soils treated with manure co-composted feed-stocks are very rare.The present investigation aimed at studying the nutrient release pattern from three soils amended with...Studies on the availability of plant nutrients in soils treated with manure co-composted feed-stocks are very rare.The present investigation aimed at studying the nutrient release pattern from three soils amended with maple tree leaves co-composted with cow manure.Soils were mixed with the compost at the rate of 20 t/hm^(2) and incubated at room temperature.Prior to incubation,plants residue samples were analyzed for total elemental concentrations(NO_(3),NH_(4),P,K,Ca,Mg,Na,Zn,Mn,Fe,Cu,Ni and Cd).Water extractability of nutrients from soils was affected by the type of soil and ratio of composted manure applied.Extractable NH_(4),P,K,Ca and Mg concentrations varied in the descending order of sandy clay,sandy loam and silt loam except NO_(3).The concentrations of P,K,Ca and Mg in the amended soils increased with the ratio of manure co-composted with leaf litter while those of NO_(3),NH_(4) and trace elements decreased.The residual nutrients in soil varied directly with their contents in the compost amendments.Co-composting improved the availability of nutrients in soils and this should be an ideal approach to managing the enormous waste generated from the livestock sector for restoring soil fertility.展开更多
基金This project is supported by National Natural Science Foundation of China (No.50205004, No. 50075075).
文摘Aiming at the discontinuous traction on contact elements of roller bearing,new concepts of sub- and micro-element are put forward. In the sub-element and micro-element,traction influence coefficient has been modified, which is calculated by the former boundary elementmethod (BEM) with roller bearing load. Hence, three-dimensional distribution of load on rollerbearing is calculated accurately. In practice, it has been proved that this method has highercalculation accuracy. An effective numerical method is offered for analyzing load characteristics ofroller bearing to improve service longevity of roller bearing and operation efficiency of rollingmill.
文摘Micro-nutrient deficiency in soil results in crop yield loss and poor seed quality. Correcting this deficiency is normally done by foliar or soil application. The objective of this research was to determine the effects of soil applications of five micro-nutrients (Mn, Cu, Zn, Mo, and B) alone and in combination with a chelating agent citric acid (CA) on soybean leaf and seed nutrients. Source of micro-nutrient compounds were MnCl2, CuCl2, ZnCl2, MoO3, and H3BO3. Our hypothesis was that micro-and macro-nutrients may be transported to leaves and then to seeds at different rates. They may interact synergistically or competitively during the uptake process. A greenhouse experiment was conducted at Mississippi Valley State University, Itta Bena, Mississippi, USA. Soybean cultivar, Bolivar (maturity group V), was applied with micro-nutrients-chelating agent citric acid at V3 and R3 (pod initiation) stage. The results showed that applications of Cu, Zn, B and Mo increased three unrolled trifoliate leaves Cu, Zn, B by 26.5%, 13.8%, 113% and Mo increased to 179 mg/kg, respectively in the leaves. Also, the application of “Cu, Zn, B and Mo increased Cu, Zn, B by 55.5%, 8.2%, 28.6% and Mo increased to 202 mg/kg” respectively in soybean seeds. Application of Mn had no direct effect on increasing Mn either in leaves or in seeds, however, Mn and Mn + CA treatment affected other mineral contents. Application of Cu, Zn, Mo, B and CA increased macro-nutrients K, N, P, Mg, and S. Irrespective of the applications, the nutrient increase trend in seed was Na > Fe > Zn > Mn > B > Cu > Mo. However, Mo application resulted in the following seed nutrient accumulation pattern: Na > Mo > Fe > Zn > Mn > B > Cu. This may suggest that Mo had higher mobility to seeds than other micro-nutrients. Combination of soil application of Mo + CA increased Mo in leaves at V3 stage;however, Mo + CA soil application during pod-filling stage had no significant effects on Mo accumulation in seeds. The current research showed that some micro-nutrient application with the chelating agent CA could increase seed nutrients. Since these results are conducted under greenhouse experiments, further research under field conditions is needed before conclusive recommendations are made.
文摘Studies on the availability of plant nutrients in soils treated with manure co-composted feed-stocks are very rare.The present investigation aimed at studying the nutrient release pattern from three soils amended with maple tree leaves co-composted with cow manure.Soils were mixed with the compost at the rate of 20 t/hm^(2) and incubated at room temperature.Prior to incubation,plants residue samples were analyzed for total elemental concentrations(NO_(3),NH_(4),P,K,Ca,Mg,Na,Zn,Mn,Fe,Cu,Ni and Cd).Water extractability of nutrients from soils was affected by the type of soil and ratio of composted manure applied.Extractable NH_(4),P,K,Ca and Mg concentrations varied in the descending order of sandy clay,sandy loam and silt loam except NO_(3).The concentrations of P,K,Ca and Mg in the amended soils increased with the ratio of manure co-composted with leaf litter while those of NO_(3),NH_(4) and trace elements decreased.The residual nutrients in soil varied directly with their contents in the compost amendments.Co-composting improved the availability of nutrients in soils and this should be an ideal approach to managing the enormous waste generated from the livestock sector for restoring soil fertility.
