Design of Zero Voltage Switching Boost DC-DC Converter Using Bond Graph Model

The research in power supply design is moving towards improving efficiency by reducing losses. Another aspect of research in power converters is its modeling as it involves multiple domains such as electrical, mechanical, magnetic...etc. bond graph modeling is suitable for the multi domain systems. Here, a zero voltage switching boost converter is designed using its bond graph model. The bond graph simulated results which are done in MATLAB/SIMULINK are matched with the experimental results. The efficiency of the ZVS boost converter is calculated and is compared with the efficiency of conventional pulse width modulated (PWM) boost converter

An Improved Flexibility Formulation for Nonlinear Analysis of Reinforced Concrete Frames

In this paper the finite element flexibility-based formulation for a reinforced concrete frame element is discussed. The formulation takes account of material non-linearity on the basis of the onedimensional stress-strain relationships akin to the traditional fibre element. However, the fibres in this method are replaced by transverse integration points to improve the efficiency of the method. The compatibility of strain in each section is satisfied by adopting the Navier-Bernoulli hypothesis and effect of shear tractions on the nonlinear response of the material is neglected. Two different iterative solution strategies based on secant and tangent stiffness, consistent with the flexibility formulation are employed for solving the governing equation. The accuracy of assumptions and performance of the solution schemes are studied by a numerical example

Consistent Mass and Exact Displacement Shape Function for a Tapered Curved Frame Element

The principle of virtual force is employed to derive the exact shape function for a taperedcurved frame element in space and these shape functions ca n be employed to calculate the exact consistent mass and geometric stiffness matrixes for curved-tapered frame elements. The lack of any displacement shape function with exact fulfilment of equilibrium equations by an accurate force interpolation is the salient feature of this approach. The formulation adopts the linear elastic behaviour of the material and the strain compatibility is satisfied based on the Nevier-Bernoulli hypothesis. Shear deformations are considered and the Saint-Venat hypothesis for torsion is adopted. The efficiency and accuracy of the formulation are verified using some numerical examples

A Multi Phase Transformation System Using a Special Transformer Connection

This paper proposes a novel transformer connection scheme to convert the three phase grid supply to a five-phase fixed voltage and fixed frequency supply. The output transformer connection outputs five phases can be used in applications requiring a five-phase supply. Multi-phase motor drives have been studied from more than thirty years. The interest has grown so that some international power electronic conferences have hosted sessions on the multi-phase motor drives. Generally, multi-phase machines drive has many advantages over conventional three-phase drive such as high power handling capability by dividing the required power between multiple phases, reduced torque pulsations and higher reliability. Three phase drive, the loss of stator phase does not prevent the machine from starting and running. The main advantages of multi-phase systems are reduced rotor harmonic currents, increased torque per ampere for the same volume machine, reduced stator copper losses. The main application areas of multiphase induction motor drives are ship propulsion, traction (including electric and hybrid electric vehicles) and the concept of more-electric aircraft. A difference between Three-Phase supply and Five-Phase supply. Other suitable applications are locomotive traction aerospace and high power applications. Presently the grid power available is only limited to three-phase so the supply to multi-phase motors is invariably given from power electronic converters

Generalized Sagnac Effect

Experiments were conducted to study light propagation in a light waveguide loop consisting of linearly and circularly moving segments. We found that any segment of the loop contributes to the total phase difference between two counterpropagating light beams in the loop. The contribution is proportional to a product of the moving velocity v and the projection of the segment length Deltal on the moving direction, Deltaphi=4pivDeltal/clambda. It is independent of the type of motion and the refractive index of waveguides. The finding includes the Sagnac effect of rotation as a special case and suggests a new fiber optic sensor for measuring linear motion with nanoscale sensitivity.Comment: 3 pages (including 3 figures

Experimental and Numerical Study of a Submarine and Propeller Behaviors in Submergence and Surface Conditions

In this paper, hull/propeller interaction of a submarine model which has a realistic geometry, in submergence and surface conditions has been studied. For this purpose, the computational fluid dynamics (CFD) method has been used to solve the viscous, incompressible, two phase flow field (in surface condition) around a model of the propeller and submarine hull with and without propeller. The rotation of the propeller has been modeled using the sliding mesh technique. For turbulent flow modeling and free surface simulation, the k-ω SST model and the volume of fluid method (VOF) have been used, respectively. Experimental data obtained from test conducted by the authors in M.U.T. towing tank have been used to validate the numerical scheme. Comparing numerical and experimental results shows good agreement. The experimental and numerical results show that operation of the propeller near water surface reduces the thrust coefficient of the propeller comparing to open water condition, so that according to experimental results the maximum relative reduction of the thrust coefficient is 8.95%. In addition, the results indicated the amount of hull resistance coefficient in surface condition is more than submergence condition. According to the thrust reduction and wake factors obtained from the numerical results, it is known that their values in surface condition are less than submergence condition. This research can be used for more realistic investigation of hull/propeller interaction and thus, more accurate powering performance prediction of submarines

Mathematical modeling of interactions of cabergoline with human serum albumin for biosensing of human serum albumin

In this work, we are going to study the interactions of cabergoline (CBG) with human serum albumin (HSA) by mathematical modeling of voltammetric and spectroscopic data. To achieve this goal, voltammetric and spectroscopic data will be augmented into a data matrix which will be resolved by multivariate curve resolution-alternating least squares (MCR-ALS) as a powerful chemometric tool. Then, the quality of the data fitting by MCR-ALS will be examined by MCR-BANDS to ensure about the absence of the rotational ambiguities in the results. Molecular docking will also be used to model the interactions of CBG with HSA for verifying the results obtained from experimental methods. Hard-modeling of the experimental data will be performed by EQUISPEC to compute the binding constant of the complex formed from the interactions of CBG with HSA for verifying the binding constant obtained by direct analysis of the experimental data. Finally, two chrono-amperometric measurements based on CBG-HSA interactions will be performed to develop a novel electroanalytical method for determination of electro-inactive HSA.Fil: Jalalvand, Ali R.. Kermanshah University of Medical Sciences; IránFil: Ghobadi, Sirous. Razi University; IránFil: Akbari, Vali. Razi University; Irán. Kermanshah University of Medical Sciences; IránFil: Goicoechea, Hector Casimiro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Desarrollo Analítico y Quimiometría; ArgentinaFil: Faramarzi, Elahe. Kermanshah University of Medical Sciences; IránFil: Mahmoudi, Majid. Kermanshah University of Medical Sciences; Irá