FLOATING RATE OF FRAZIL ICE PARTICLES IN FLOWING WATER IN BEND CHANNELS——A THREE-DIMENSIONAL NUMERICAL ANALYSIS

In this article, based on the theory of two-phase flow and laboratory data, a three-dimensionally model is developed to simulate the floating rates of frazil ice particles in water under covered condition. The Lagrangian trajectory method is used in the three dimensional simulation for floating rates of fxazil ice particles along a 180° bend channel. The velocity profiles in longitudinal and transverse directions, the turbulence intensity, and the residual pressure are simulated. Under the condition of gravitational similarity, the simulated floating rates of frazil ice particles in the model bend channel and the prototype bend channels are compared. Results indicate that the profiles for floating rates of ice particles for flows in the model channel are similar to those in the prototype bend channels. The simulated floating rates of ice particles are clearly higher along the convex bank than along the concave bank at each cross section. For the prototype bend channel in a large model scale, the variation of floating rate across each cross section is relatively small.

Modelling State Foreign Exchange Reserves under the Managed Floating Exchange Rate System in China

The purpose of this paper is to investigate China′s state foreign exchange reserves growth using monthly data in the period January 1994 to December 1998. An economic model is constructed, with a view from its formation mechanism. Time series techniques are used to examine the long run relationship between foreign exchange reserves and the variables included in the model. Our empirical investigation revealed existence of a systematic long run relationship among foreign exchange reserves, exports, imports, and foreign direct investment. In the short run, the Asian financial crises have not significant effect on China′s foreign exchange reserves. Moreover, the recursive tests results indicated that the error correction model was structurally stable over the sample period, implying that the reserve holdings play a significant role in the balance payments adjustment process and separating China economy from the Asian financial crises.

Use of float consumption rate in resource leveling of construction projects

The management of resources has been claimed to be as important as scheduling methods.Inefficiency in managing resources may bring about severe delays and cost overruns caused by resource shortages in some cases and/or idle resources in others.Therefore,resources should be utilized efficiently to prevent project failures.Resource leveling is one of the approaches that are used for the management of resources.It aims to minimize fluctuations,peaks,and valleys in resource utilization without changing the completion time of a project and the number of resources required.Although the main principle behind traditional resource leveling is achieving an even flow of resources while the original project duration remains unchanged,the literature supports the need to develop an efficient model that discriminates among the activities that are selected for participation in resource leveling.For this purpose,this study has developed a model that considers the float consumption rates of activities in resource leveling.The float consumption rate is the percentage that is set to determine the maximum amount of float which will be consumed to shift the start time of the activity.The proposed model allows a scheduler to assign float consumption rates to each activity that can be used during the resource leveling procedure.When the required information is inputted,the proposed model automatically changes the required daily resources as it shifts the noncritical activities along their available total float times.The proposed model is expected to minimize the likelihood of severe delays and cost overruns.The model is demonstrated by constructing a network and its resource utilization histograms.