Rock excavation in quarries is normally carried out by using explosives. The steps in planning of cutting face are based on the appropriate design for angles of cut and the optimum consumption of charge weights. Prior...Rock excavation in quarries is normally carried out by using explosives. The steps in planning of cutting face are based on the appropriate design for angles of cut and the optimum consumption of charge weights. Priority procedures in planning are the stability of bench excavation,vibration evaluation,and the selection for the blast patterns. The methods of analysis are described and compared with field results. From several cases of trial cut angles and changing geometry of blast dimensions,the result of an optimum pattern in a specific quarry,with respect to the acceptable global unit cost is achieved.展开更多
Linear risk programming was used to determine the optimum cultivation pattern to increase incomes of poplar farmers.Seven clones of Populus deltoides Bartr.ex Marsh.were examined in Guilan province,northern Iran.Growt...Linear risk programming was used to determine the optimum cultivation pattern to increase incomes of poplar farmers.Seven clones of Populus deltoides Bartr.ex Marsh.were examined in Guilan province,northern Iran.Growth and price data were taken from previous research at the Safrabaste Poplar Research Station and in interviews with farmers.The Lingo software was used to analyze the data in different forms of E.The results show that when risk was considered,the optimal solution included the clones Pd63/51-x1,-Pd72/51-x3,Pd73/51-x4 and Pd79/51-x6.There was a high growth fluctuations of the clones Pd69/55-x2,Pd77.51-x5,and Pd caroliniensis-x7 and were not included in cultivation plans.Furthermore,the existing farm plans executed by local farmers,is neither profitoriented nor efficient in terms of income risk management according to risk efficient frontier.These results could help farmers with different levels of risk-aversion to select proper planting plans.展开更多
The calculation of productivity and the choice of well pattern of mixedhorizontal and vertical wells were discussed in this paper. Because the naturall drainage areas ofhorizontal wells are oval rather than circular, ...The calculation of productivity and the choice of well pattern of mixedhorizontal and vertical wells were discussed in this paper. Because the naturall drainage areas ofhorizontal wells are oval rather than circular, rectangular drainage well patterns should beadopted. Using pseudo 3-di-mensional method and conformal transformation, the potential function ofa row of horizontal wells was deduced. Using this function and the superposition principle, ananalytical solution of the productivity for the rectangular mixed well pattern was given.Quantitative means for defining the shapes of the optimum pattern were developed in this paper byintroducing two dimensionless parameters, the shape factor and dimensionless length of horizontalwell. The formula for productvity was used to optimize the mixed well patterns. The curves of theoptimized shape factor against dimensionless length of horizontal well were drawn. The results showthat the pattern area and formation thickness have no effect on the optimal shape factors and can beapplied to the design of development for oil fields.展开更多
Pteroceltis tatarinowii is one of the native precious tree species of China and the bark is the main raw material for manufacturing Xuan paper. Based on the introduction of resource distribution and ecological charact...Pteroceltis tatarinowii is one of the native precious tree species of China and the bark is the main raw material for manufacturing Xuan paper. Based on the introduction of resource distribution and ecological characteristics of P. tatarinowii, this paper summarized current and advanced science and technology of the studies and management of this species in recent 20 years, which include the relationship between bark quality of P. tatarinowii and Xuan Paper, the key techniques related to improving seedling production and plantation productivity, and establishment of optimum silviculture patterns of P. tatarinowii. The development potential and further required study of P. tatarinowii plantations were also discussed and prospected. The paper will provide some bases for directive silviculture of P. tatarinowii plantation and sustainable development of Xuan Paper production.展开更多
文摘Rock excavation in quarries is normally carried out by using explosives. The steps in planning of cutting face are based on the appropriate design for angles of cut and the optimum consumption of charge weights. Priority procedures in planning are the stability of bench excavation,vibration evaluation,and the selection for the blast patterns. The methods of analysis are described and compared with field results. From several cases of trial cut angles and changing geometry of blast dimensions,the result of an optimum pattern in a specific quarry,with respect to the acceptable global unit cost is achieved.
文摘Linear risk programming was used to determine the optimum cultivation pattern to increase incomes of poplar farmers.Seven clones of Populus deltoides Bartr.ex Marsh.were examined in Guilan province,northern Iran.Growth and price data were taken from previous research at the Safrabaste Poplar Research Station and in interviews with farmers.The Lingo software was used to analyze the data in different forms of E.The results show that when risk was considered,the optimal solution included the clones Pd63/51-x1,-Pd72/51-x3,Pd73/51-x4 and Pd79/51-x6.There was a high growth fluctuations of the clones Pd69/55-x2,Pd77.51-x5,and Pd caroliniensis-x7 and were not included in cultivation plans.Furthermore,the existing farm plans executed by local farmers,is neither profitoriented nor efficient in terms of income risk management according to risk efficient frontier.These results could help farmers with different levels of risk-aversion to select proper planting plans.
文摘The calculation of productivity and the choice of well pattern of mixedhorizontal and vertical wells were discussed in this paper. Because the naturall drainage areas ofhorizontal wells are oval rather than circular, rectangular drainage well patterns should beadopted. Using pseudo 3-di-mensional method and conformal transformation, the potential function ofa row of horizontal wells was deduced. Using this function and the superposition principle, ananalytical solution of the productivity for the rectangular mixed well pattern was given.Quantitative means for defining the shapes of the optimum pattern were developed in this paper byintroducing two dimensionless parameters, the shape factor and dimensionless length of horizontalwell. The formula for productvity was used to optimize the mixed well patterns. The curves of theoptimized shape factor against dimensionless length of horizontal well were drawn. The results showthat the pattern area and formation thickness have no effect on the optimal shape factors and can beapplied to the design of development for oil fields.
文摘Pteroceltis tatarinowii is one of the native precious tree species of China and the bark is the main raw material for manufacturing Xuan paper. Based on the introduction of resource distribution and ecological characteristics of P. tatarinowii, this paper summarized current and advanced science and technology of the studies and management of this species in recent 20 years, which include the relationship between bark quality of P. tatarinowii and Xuan Paper, the key techniques related to improving seedling production and plantation productivity, and establishment of optimum silviculture patterns of P. tatarinowii. The development potential and further required study of P. tatarinowii plantations were also discussed and prospected. The paper will provide some bases for directive silviculture of P. tatarinowii plantation and sustainable development of Xuan Paper production.
