This paper investigates the heat transfers and ablation of thermal insulators used in motors and nozzles. The heat and mass transfer equations are considered in two dimensions in a convergent-divergent nozzle. The finite volume method and the implicit method for time dependence have been used to solve these equations. We used the equations finite volume method with implicit formulation for time dependency to solve equations. The reaction equation, which is written in the form of Arrhenius, is solved using the Runge-Kutta method, and the density and the flux of the gas produced at each step are obtained. Also, we represent a model for the rate of recession. The validation of the model is compared with the experimental results in silica-phenolic ablation insulators and shows a good agreement of the simulation results with the experimental observations. After validation of the obtained results. The effect of the Blowing Correction coefficient has been investigated, the results show that this coefficient is very important for the accurate design of ablation insulators. The Blowing Correction Factor reduces the convection heat transfer coefficient, reduces the surface recession, and thus, reduces the back temperature of the insulation. Therefore, in cases where the thickness of the insulation is significant or the heat of ablation is low. This parameter can be important and affect the final results and thus the final design.

The paper presents a simple and economical control scheme for reducing the input current distortion in a boost-type AC-DC converter by employing rectified-voltage PWM. The method is described for a single-phase converter, and simulation and experimental results are presented. The method is extended to a three-phase single-switch converter and simulation results are given.

The derivation of the static reference Corrections was generally based on a fairly simple geological model close to the surface. The lack of detailed information near the surface leads to inaccuracies in this model and, therefore, in static Corrections. Residual static Corrections are designed to correct small inaccuracies in the near-surface model. Their application should lead to an improvement of the final section treated compared to that in which only static Corrections is applied. For example, if the final stacked section is to be inverted to produce an acoustic impedance section, it is important that the variations in amplitude along the section represent the changes in the reflection coefficient as close as possible. This is unlikely to be the case if small residual static errors are present. In addition, static reference Corrections are not a unique set of values because a change in reference results in a different set of Corrections. Due to variation in the Earth's surface, velocities, and thicknesses of near-surface layers, the shape of the travel time hyperbola changes. These deviations, called static, result in misalignments and events lost in the CMP, so they must be corrected during the processing. After correcting the statics of long wavelengths, there are still some short-wavelength anomalies. These “residual” statics are due to variations not counted in the low-velocity layer. The estimation of the residual static in complex areas is one of the main problems posed by the processing of seismic data, and the results from this processing step affect the quality of the final reconstructed image and the results of the interpretation. Residual static can be estimated by different methods such as travel time inversion, power stacking, and sparsity maximization, which are based on a coherent surface assumption. An effective method must be able to denoise the seismic signal without losing useful data and have to function properly in the presence of random noise. In the frequency domain, it is possible to separate the noise from the main data, so denoising in the frequency domain can be useful. Besides, the transformation areas are data-driven and require no information below the surface. The methods in the frequency domain generally use the Fourier transform, which takes time and has certain limits. Wavelet transformation methods always provide a faster procedure than Fourier transformation. We have found that this type of wavelet transform could provide a data-oriented method for analyzing and synthesizing data according to the oscillation behavior of the signal. Tune able Q Factor Discrete Wavelet Transform (TQWT) is a new method that provides a reliable framework for the residual static Correction. In this transformation, the quality Factor (Q), which relates to the particular oscillatory behavior of the data, could be adjusted in the signal by the user, and this characteristic leads to a good correspondence with the seismic signal. The Q Factor of an oscillatory pulse is the ratio of its center frequency to its bandwidth. TQWT is developed by a tow channel filter bank. The use of a low-pass filter eliminates high-frequency data,these high-frequency components are the effect of residual static. After filtering, the data will be smoother,this amount of Correction gives the time offset for the residual static Correction. This time difference must apply to all traces. Applying this method to synthetic and real data shows a good Correction of the residual static.

This study investigates the reinforcement Correction Factor of concrete core in more detail to prepare appropriate outlines for interpretation of results. This investigation aims to minimize uncertainties involved to carry out the more realistic condition assessment of suspect buildings before taking up retrofitting/strengthening measures. For this purpose, an extensive experimental program including different concrete strength level, moisture condition, core size, length-to-diameter (L/D) ratio of core and steel bar size with various configurations was under taken. The effect of variation of foregoing parameters on the ratio of average compressive strength of cores containing steel bars to that of corresponding plain specimens was probed. The results show that the Correction Factors are highly dependent on the values of volume percentage and position of reinforcing bars in the core, which are extremely interrelated. Hence, the experimental results do not show a good agreement with the provisions by the British Standard 6089 and Concrete Society Report No. 11. Therefore, a statistical analysis on the prediction of cube compressive strength using linear and nonlinear regression models is accomplished. The results showed that regression models have great ability as a feasible tool for prediction of compressive strength on the basis of core testing in the presence of steel bars. However, the most accurate results obtained by nonlinear equations in comparison with linear models.

Most existing power converters and industrial motor drive systems draw non-sinusoidal currents from the supply. Non-sinusoidal currents contained harm harmonics disturb the power supply which it causes serious concern for reliability. Other equipments that use the same power supply are adversely affected. This paper suggests the operation and performance of a new modified AC/DC converter that allows bi-directional power flow. It also provides improved power Factor and reduces harmonic magnitude and disturbance to the supply by system. The bi-directional feature allows recovery of regenerative energy of loads, back to the power supply and the converters. The proposed converter has high potential for industrial applications, such as electronically controlled traction system, lifts and generally industrial motor drive systems which can increase overall efficiency and reliability.

In small towing tanks, due to tank and model dimension limitations, tests have been performed at low Reynolds number and laminar flow regimes. In this condition, flow momentum is low and as a result, the probability of flow separation is high. This has been resulted to a difference in flow behavior around the model and prototype. Therefore the scale effect in model testing cannot be avoided, which will be grater in small towing tanks. For Correction of results in all towing tanks, the scale effect Correction Factor has been used. This paper is a result of tests done on a model of a 35000 tons Product Carrier. Tests have been done with and without a turbulent simulator and the scale Correction Factor for both conditions has been evaluated. Results show that, without a turbulent simulator, this Factor approximately has been changed linearly. And, in the case of using a turbulent simulator, the amount of this Factor decreased extremely and varied nonlinearly.