Nonlinear Compensation Empyoing Matrix Converter with DTC Controller

This paper describes a nonlinear harmful speed and torque controller for fourth order induction motor model. The investigation of optimality and cost function for that base on estimation of Hammerstein-Wiener model with the compensated mathematical model. The matrix converter with direct torque control combination is efficient way to get better performance specifications in the industry.The MC and the DTC advantages are combined together.The reduction of complexity and cost of DC link in the DTC since it has no capacitors in the circuit. However, the controlling torque is a big problem it in DTC because of high ripple torque production which results in vibrations response in the operation of the IM as it has no PID to control the torque directly. The combination of MC with DTC is applied to reduce the fluctuation in the output torque and minimize the steady state error. This paper presents the simulation analysis of induction machine drives using Maltlab/Simulink toolbox R2012a. Design of constant switching frequency MCDTC drive,stability investigation and fault protection as well as controllability and observability with minimum steady state error has been carried out which  proved the effectiveness of the proposed technique

Radiation effect on viscous flow of a nanofluid and heat transfer over a nonlinearly stretching sheet

In this work, we study the flow and heat transfer characteristics of a viscous nanofluid over a nonlinearly stretching sheet in the presence of thermal radiation, included in the energy equation, and variable wall temperature. A similarity transformation was used to transform the governing partial differential equations to a system of nonlinear ordinary differential equations. An efficient numerical shooting technique with a fourth-order Runge-Kutta scheme was used to obtain the solution of the boundary value problem. The variations of dimensionless surface temperature, as well as flow and heat-transfer characteristics with the governing dimensionless parameters of the problem, which include the nanoparticle volume fraction ϕ, the nonlinearly stretching sheet parameter n, the thermal radiation parameter NR, and the viscous dissipation parameter Ec, were graphed and tabulated. Excellent validation of the present numerical results has been achieved with the earlier nonlinearly stretching sheet problem of Cortell for local Nusselt number without taking the effect of nanoparticles

Numerical Prediction of Stresses at High Temperature of 3rd Generation Advanced High Strength Steels During Resistance Spot Welding - Liquid Metal Embrittlement Risk Assessment. Methodology to Create and Validate a Reliable and Robust Numerical Material Card

The prediction of stress level during Resistance Spot Welding at high temperature is very useful to reduce and/or avoid Liquid Metal Embrittlement phenomenon. However, the experimental estimation of stress level into metal sheets during a Resistance Spot Welding process is impractical. Therefore, a numerical methodology to predict mechanical stresses, using more accessible experiments, is proposed in this work

Effects of high-intensity interval training and plyometric exercise on the physical fitness of junior male handball players

OBJECTIVE This study analyzed the effects of high intensity interval training (HIIT) combined with plyometric exercise on the physical fitness of junior male handball players. PATIENTS AND METHODS Subjects (age ~17 years) were randomly divided between experimental (n=17) and control (n=15) groups. During the 8-week intervention, the experimental group replaced a part of their regular regimen by HIIT, combined with plyometric exercise. Assessments in both groups before and after the intervention included: squat jump (SJ), countermovement jump (CMJ), sprint performance (5 m, 10 m, 20 m and 30 m), change of direction tests (Illinois modified test [Illinois-MT] and T-half test), 20-m shuttle run, and repeated sprint T-test. RESULTS The two-way analyses of variance revealed significant group-time interactions (all p<0.05), favoring the intervention group in 5 m, 10 m, 20 m and 30 m sprint (d=0.33, 8.3%; d=0.52, 7.6%; d=0.57, 6.8%; and d=0.58, 8.8%, respectively), T-half (d=0.25, 5.1%), Illinois-MT (d=0.47, 4.2%), SJ and CMJ (d=0.34-0.39, 34-4-34.9%), repeated sprint T-test best time, mean time and total time (d=0.83, 6.9%; d=0.62, 7.4%; and d=0.61, 7.2%, respectively), 20 meter shuttle run test aerobic maximum speed and predicted maximal oxygen intake (d=0.36, 7.5%; d=0.19, 9.4%, respectively). CONCLUSIONS HIIT combined with plyometrics can aid in the development of physical fitness abilities, which are extremely important to junior male handball players

The relationship between locus of control and pre-competitive anxiety in highly trained soccer players

IntroductionPrevious studies have not considered the potential association between locus of control and precompetitive anxiety in elite soccer players. Accordingly, this cross-sectional study examined The prediction of locus of control on precompetitive anxiety in highly trained cadet soccer players.ObjectiveBased on a literature review, our research question was: can the locus of control be considered as an explanatory element of precompetitive anxiety?MethodsThirty-five Tunisian highly trained soccer players licensed from two regional soccer clubs aged between 15 and 16 years participated in the resent study. All participants were evaluated using the Competitive State Anxiety Inventory-2 (CSAI-2) and the Internal-External Locus of Control Scale. The relationship between measures of anxiety, self-confidence and the locus of control scores were analyzed using Pearson’s product–moment correlation coefficient. Further, multiple linear stepwise multiple regression models were calculated to determine the most robust predictors of the locus of control.ResultsBased on our findings, the regression analysis explains up to 21.3% of the total variation of our independent variable (locus of control) and explains only 21.3% of the variability of our dependent variable somatic anxiety. Furthermore, locus of control explains 61.9% of the variability in self-confidence.ConclusionThe locus of control can be used for the detection and selection of young athletic talent to identify individuals with the best psychological aptitude to cope with psychological problems related to sports performance. Preparing highly trained soccer players on how to deal with their anxiety could prevent them from becoming overwhelmed when they feel powerless to change their situation during competition

A randomised controlled trial of 1- versus 2-day per week formats of Nordic hamstring training on explosive athletic tasks in prepubertal soccer players

Purpose: This randomised controlled trial examined the effect of volume-equated programmes of Nordic hamstring exercise (NHE) training, executed at frequencies of 1- or 2-days per week, on explosive athletic tasks (30 m sprint, 15 m manoeuvrability and standing long jump [SLJ]) in male youth soccer players (mean age: 10.3 ± 0.5 years). Materials and methods: Players were divided into an experimental group (n=31) which was further subdivided into 1-day (n=16) and 2-days (n=15) per week training conditions, and a control group (n=14). Results: There were significant group-by-time interactions for 30-m sprint (p<0.001, d=0.6), SLJ (p=0.001, d=1.27) and 15 m manoeuvrability (p<0.001, d=0.61). The experimental group demonstrated small to moderate effect sizes in 30-m sprint (d=0.42, p=0.077), SLJ (d=0.97, p<0.001) and 15 m manoeuvrability (d=0.61, p<0.001). The control group showed small significant performance decrements or no change in these variables. There were no significant differences between the 1-day and 2-day training groups. In two of the three tests (30 m sprint, SLJ) the 2-day group demonstrated larger effect sizes. Conclusion: The NHE enhances explosive athletic task performance in prepubertal youth soccer players and there may be only small advantages to spreading training over two days instead of one

MHD Forced Convection Laminar Boundary Layer Flow of Alumina-Water Nanofluid over a Moving Permeable Flat Plate with Convective Surface Boundary Condition

This paper analyses a two-dimensional steady forced convection boundary layer viscous incompressible flow of alumina-water nanofluid over a moving permeable vertical flat plate under the effect of a magnetic field normal to the plate. Thermal convective surface boundary condition is applied. The nanofluid formulated in the present study is water dispersed with various volumetric fractions of the alumina (Al2O3) nanoparticles. The plate velocity and the free stream velocities are considered to be proportional to , while the magnetic field and suction velocities are taken to be proportional to . The similarity solution of the governing problem is obtained. Numerical studies are presented to show the effect of the nanoparticle volume fraction the convective heat transfer parameter , the power law exponent , the wall velocity parameter , and the suction parameter fw on the velocity, temperature, skin-friction coefficient, and Nusselt number

A two-dimensional axially-symmetric model of keyhole and melt pool dynamics during spot laser welding

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