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In this research a mathematical model was developed to study bed elevation variation of alluvial rivers. It utilizes two principal modules of hydraulics and sediment transport for simulation purposes. SDAR (Scour and Deposition model of Alluvial Rivers) is a new model with both one and semi-two dimensional (S-2D) computational schemes. It is regarded S-2D in a sence that lateral variation of velocity, hydraulic stresses, and geometrical specifications are achieved by dividing the main channel into serveral stream tubes. In order to overcome the existing limitations, a new idea of reachwise stream tube concept was also introduced. This allows to include branch connections and withdrawal points across the tube barriers. Sediment routing and bed variation calculations are accomplished along each river strip desigated by virtual interfaces of the tubes. Presently, quasi-steady gradually varied flows are processed by the model. It should also be emphasised that this version is only valid for alluvial rivers composed of noncohesive bed material. To assess the model, several river cases and laboratory data base were used. During calibration runs, the ability of model in longitudinal and transversal bed profile simulation and armor layer development predection were especially detected. Results of simulation are also compared with the results of well-known models, e.g. HEC-6, GSTARS-2, and FLUVIAL-I2. It was found that the ability of model in simulating bed variation is noticeably increased when S-2D concept is introduced. Indeed, the comparative validity tests confirm SDAR"s promising functioning in facing with complex real engineering cases. Obviously more article discussions would bring oppurtunities to demonestrate it"s technical cappabilities profoundaly.

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Shear modulus and damping ratio are important input parameters in dynamic analysis. A series of resonant column tests was

carried out on pure clays and sand-clay mixtures prepared at different densities to investigate the effects of aggregate content,

confining stress, void ratio and clay plasticity on the maximum shear modulus and minimum damping ratio. Test results revealed

an increase in the maximum shear modulus of the mixture with the increase in sand content up to 60%, followed by a decrease

beyond this value. It was also found that the maximum shear modulus increases with confining stress, and decreases with void

ratio. In addition, minimum damping ratio increases with sand content and clay plasticity and decreases with confining stress.

Finally, on the basis of the test results, a mathematical model was developed for the maximum shear modulus.

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Magnetic levitation (maglev) is amongst the most advanced technologies that are available to the transportation industries. It

has already been noticed by decision makers in many countries around the globe. Contrary to such high levels of interest, there

are no practical algorithms available to the engineers and/or managers to assist them in analyzing economics of the maglev

systems. Therefore, it has been the purpose of this research to find appropriate answers to such vital questions and also investigate

feasibility for practical use of maglev technology in rapid transit systems. The life cycle costs (LCC) for the maglev system

including the cost of initiating such projects are included in this survey and are evaluated. To serve the purpose, an algorithm is

presented that facilitates the technical and economical analyses of maglev systems. The proposal for a long distance maglev

system, Mashhad-Tehran (M-T), is used as a case study by using the proposed algorithm. Moreover, the cost of establishing and

operating M-T project is estimated by two other different approaches. These include the already established mathematically based

cost estimating method, and the cost estimations based on the international norms and standards. These standards are based on

statistical (or provided) data. Such cost estimations assist verification of the proposed algorithm. Comparisons between outcomes

of the three methods prove close agreement for the cost estimation by all of them. It is concluded that the proposed algorithm for

implementation and operation of maglev route is practical.