This paper is concerned with the design and application of coaxial mixers with the aid of analysis of interaction between each individual impeller. Two types of coaxial mixers pitched blade turbine(PBT)-helical ribbon...This paper is concerned with the design and application of coaxial mixers with the aid of analysis of interaction between each individual impeller. Two types of coaxial mixers pitched blade turbine(PBT)-helical ribbon(HR)and inner-outer HR operated in laminar regime were studied experimentally and numerically. The interaction implies synergistic and interference effects, which was revealed through the investigation of axial circulation rate, energy dissipation rate and power consumption. The influence factors including rotational speed ratio,rotating mode and impeller configuration were explored systematically. Quantitative analysis of power consumption involves three parameters: rate of variation in power consumption, interactive mode and ratio of power consumption. Analysis indicated that some important properties were embodied in the power curve.These properties are one-way and two-way interactions, critical speed ratio and dominant impeller. Finally, a new suggestion for power estimation was given.展开更多
This article questions the reliability of the amount of revenue recognized in the percentage of completion （POC） method of revenue recognition in construction industry and recommends a new method based on the progre...This article questions the reliability of the amount of revenue recognized in the percentage of completion （POC） method of revenue recognition in construction industry and recommends a new method based on the progress billing which is more reliable. The most commonly used method of revenue recognition in the construction industry is the percentage of completion method （POC）, where the revenue is recognized on the basis of the percentage of work completed. The calculation of percentage of work completed is made on the basis of the cost incurred for the contract work during the financial period and the cost required for completion of the work as estimated by the contractor. Here, the acceptance of the product by the buyer （contractee） is not involved in recognizing the revenue. The reliability of the amount of revenue and its collectability can be assured only when the buyer accepts the product. The approval of the progress bill by the contractee is needed to assure the reliability and collectability and it must be the event that triggers the recognition of revenue.展开更多
This paper considers the problem of minimizing the VaR and CTE of an insurer＇s retained risk by controlling the combinational quota-share and stop-loss reinsurance strategy. With a constrained reinsurance premium, th...This paper considers the problem of minimizing the VaR and CTE of an insurer＇s retained risk by controlling the combinational quota-share and stop-loss reinsurance strategy. With a constrained reinsurance premium, the authors give the explicit reinsurance forms and the minimal VaR and CTE of retained risk in the case of quota-share after stop-loss reinsurance and the case of stop-loss afterquota-share reinsurance respectively. Finally, the authors conclude that the quota-share after stop-loss is a better reinsurance strategy than stop-loss after quota-share to minimize the VaR and CTE with a same constrained reinsurance premium. And the pure stop-loss reinsurance is preferred for an insurer with a high level regulatory requirement.展开更多
基金Supported by the Shanghai Institute of Technology(10120K146098)Shanghai Municipal Education Commission(1021ZK151009017)
文摘This paper is concerned with the design and application of coaxial mixers with the aid of analysis of interaction between each individual impeller. Two types of coaxial mixers pitched blade turbine(PBT)-helical ribbon(HR)and inner-outer HR operated in laminar regime were studied experimentally and numerically. The interaction implies synergistic and interference effects, which was revealed through the investigation of axial circulation rate, energy dissipation rate and power consumption. The influence factors including rotational speed ratio,rotating mode and impeller configuration were explored systematically. Quantitative analysis of power consumption involves three parameters: rate of variation in power consumption, interactive mode and ratio of power consumption. Analysis indicated that some important properties were embodied in the power curve.These properties are one-way and two-way interactions, critical speed ratio and dominant impeller. Finally, a new suggestion for power estimation was given.
文摘This article questions the reliability of the amount of revenue recognized in the percentage of completion （POC） method of revenue recognition in construction industry and recommends a new method based on the progress billing which is more reliable. The most commonly used method of revenue recognition in the construction industry is the percentage of completion method （POC）, where the revenue is recognized on the basis of the percentage of work completed. The calculation of percentage of work completed is made on the basis of the cost incurred for the contract work during the financial period and the cost required for completion of the work as estimated by the contractor. Here, the acceptance of the product by the buyer （contractee） is not involved in recognizing the revenue. The reliability of the amount of revenue and its collectability can be assured only when the buyer accepts the product. The approval of the progress bill by the contractee is needed to assure the reliability and collectability and it must be the event that triggers the recognition of revenue.
基金This research is supported by Supported by the Natural Science Foundation of China under Grant Nos. 10701082 and 70801068, the major program of Key Research Institute of Humanities and Social Sciences at Universities （08JJD790145）, and a grant from the ＂project 211 （Phase III）＂.
文摘This paper considers the problem of minimizing the VaR and CTE of an insurer＇s retained risk by controlling the combinational quota-share and stop-loss reinsurance strategy. With a constrained reinsurance premium, the authors give the explicit reinsurance forms and the minimal VaR and CTE of retained risk in the case of quota-share after stop-loss reinsurance and the case of stop-loss afterquota-share reinsurance respectively. Finally, the authors conclude that the quota-share after stop-loss is a better reinsurance strategy than stop-loss after quota-share to minimize the VaR and CTE with a same constrained reinsurance premium. And the pure stop-loss reinsurance is preferred for an insurer with a high level regulatory requirement.
