A literature survey on AC-DC Converter using three phase single stage PFC & PWM Technique

Today to achieve ac-dc power conversions with high input power factor and low harmonic distortions, Power factor correction (PFC) converters are widely used. This paper lays out the research and development done in the field of PFC’s. Converter topologies, control strategies, power quality etc has been discussed here. Higher power ratings, faster switching speed and lower cost are the areas of concern for digital controllers and converters and thus PFC has gained attention

Non-Convex Economic Dispatch with Prohibited Operating Zones through Gravitational Search Algorithm

This paper presents a new approach to the solution of optimal power generation for economic load dispatch (ELD) using gravitational search algorithm (GSA) when all the generators include valve point effects and some/all of the generators have prohibited operating zones. In this paper a gravitational search algorithm is suggested that deals with equality and inequality constraints in ELD problems. A constraint treatment mechanism is also discussed to accelerate the optimization process. To verify the robustness and superiority of the proposed GSA based approach, a practical sized 40-generators case with valve point effects and prohibited operating zones is considered. The simulation results reveal that the proposed GSA approach ensures convergence within an acceptable execution time and provides highly optimal solution as compared to the results obtained from well established heuristic optimization approaches

Numerical Approximate Methods for Solving Linear and Nonlinear Integral Equations

Integral equation has been one of the essential tools for various area of applied mathematics. In this work, we employed different numerical methods for solving both linear and nonlinear Fredholm integral equations. A goal is to categorize the selected methods and assess their accuracy and efficiency. We discuss challenges faced by researchers in this field, and we emphasize the importance of interdisciplinary effort for advancing the study on numerical methods for solving integral equations. Integral equations can be viewed as equations which are results of transformation of points in a given vector spaces of integrable functions by the use of certain specific integral operators to points in the same space. If, in particular, one is concerned with function spaces spanned by polynomials for which the kernel of the corresponding transforming integral operator is separable being comprised of polynomial functions only, then several approximate methods of solution of integral equations can be developed. This work, specially, deals with the development of different wavelet methods for solving integral and intgro-differential equations. Wavelets theory is a relatively new and emerging area in mathematical research. It has been applied in a wide range of engineering disciplines; particularly, wavelets are very successfully used in signal analysis for waveform representations and segmentations, time frequency analysis, and fast algorithms for easy implementation. Wavelets permit the accurate representation of a variety of functions and operators. Moreover, wavelets establish a connection with fast numerical algorithms. Wavelets can be separated into two distinct types, orthogonal and semi-orthogonal. The preliminary concept of integral equations and wavelets are first presented in Chapter 1. Classification of integral equations, construction of wavelets and multi-resolution analysis (MRA) have been briefly discussed and provided in this chapter. In Chapter 2, different wavelet methods are constructed and function approximation by these methods with convergence analysis have been presented. In Chapter 3, linear semi-orthogonal compactly supported B-spline wavelets together with their dual wavelets have been applied to approximate the solutions of Fredholm integral equations (both linear and nonlinear) of the second kind and their systems. Properties of these wavelets are first presented; these properties are then utilized to reduce the computation of integral equations to some algebraic equations. Convergence analysis of B-spline method has been discussed in this chapter. Again, in Chapter 4, system of nonlinear Fredholm integral equations have been solved by using hybrid Legendre Block-Pulse functions and xiii Bernstein collocation method. In Chapter 5, two practical problems arising from chemical phenomenon, have been modeled as Fredholm- Hammerstein integral equations and solved numerically by different numerical techniques. First, COSMO-RS model has been solved by Bernstein collocation method, Haar wavelet method and Sinc collocation method. Second, Hammerstein integral equation arising from chemical reactor theory has been solved by B-spline wavelet method. Comparison of results have been demonstrated through illustrative examples. In Chapter 6, Legendre wavelet method and Bernoulli wavelet method have been developed to solve system of integro-differential equations. Legendre wavelets along with their operational matrices are developed to approximate the solutions of system of nonlinear Volterra integro-differential equations. Also, nonlinear Volterra weakly singular integro-differential equations system has been solved by Bernoulli wavelet method. The properties of these wavelets are used to reduce the system of integral equations to a system of algebraic equations which can be solved numerically by Newton's method. Rigorous convergence analysis has been done for these wavelet methods. Illustrative examples have been included to demonstrate the validity and applicability of the proposed techniques. In Chapter 7, we have solved the second order Lane-Emden type singular differential equation. First, the second order differential equation is transformed into integro-differential equation and then solved by Legendre multi-wavelet method and Chebyshev wavelet method. Convergence of these wavelet methods have been discussed in this chapter. In Chapter 8, we have developed a efficient collocation technique called Legendre spectral collocation method to solve the Fredholm integro-differential-difference equations with variable coefficients and system of two nonlinear integro-differential equations which arise in biological model. The proposed method is based on the Gauss-Legendre points with the basis functions of Lagrange polynomials. The present method reduces this model to a system of nonlinear algebraic equations and again this algebraic system has been solved numerically by Newton's method. The study of fuzzy integral equations and fuzzy differential equations is an emerging area of research for many authors. In Chapter 9, we have proposed some numerical techniques for solving fuzzy integral equations and fuzzy integro-differential equations. Fundamentals of fuzzy calculus have been discussed in this chapter. Nonlinear fuzzy Hammerstein integral equation has been solved by Bernstein polynomials and Legendre wavelets, and then compared with homotopy analysis method. We have solved nonlinear fuzzy Hammerstein Volterra integral equations with constant delay by Bernoulli wavelet method and then compared with B-spline wavelet method. Finally, fuzzy integro-differential equation has been solved by Legendre wavelet method and compared with homotopy analysis method. In fuzzy case, we have applied two-dimensional numerical methods which are discussed in chapter 2. Convergence analysis and error estimate have been also provided for Bernoulli wavelet method. xiv The study of fractional calculus, fractional differential equations and fractional integral equations has a great importance in the field of science and engineering. Most of the physical phenomenon can be best modeled by using fractional calculus. Applications of fractional differential equations and fractional integral equations create a wide area of research for many researchers. This motivates to work on fractional integral equations, which results in the form of Chapter 10. First, the preliminary definitions and theorems of fractional calculus have been presented in this chapter. The nonlinear fractional mixed Volterra-Fredholm integro-differential equations along with mixed boundary conditions have been solved by Legendre wavelet method. A numerical scheme has been developed by using Petrov-Galerkin method where the trial and test functions are Legendre wavelets basis functions. Also, this method has been applied to solve fractional Volterra integro-differential equations. Uniqueness and existence of the problem have been discussed and the error estimate of the proposed method has been presented in this work. Sinc Galerkin method is developed to approximate the solution of fractional Volterra-Fredholm integro-differential equations with weakly singular kernels. The proposed method is based on the Sinc function approximation. Uniqueness and existence of the problem have been discussed and the error analysis of the proposed method have been presented in this chapte

An iterative method for solving time-fractional partial differential equations with proportional delays

This article deals with an iterative method which is a new formulation of Adomian decomposition method for solving time-fractional partial differential equations (TFPDEs) with proportional delays. The fractional derivative taken here is in Caputo sense. Daftardar-Gejji and Jafari (2006) proposed this new technique where the nonlinearity is defined by using the new formula of Adomian polynomials and the new iterative formula (NIF) is independent of λ. It does not require any discretization, perturbation, or any restrictive parameters. It is shown that the NIF converges rapidly to the exact solutions. Three test problems have been illustrated in order to confirm the efficiency and validity of NIF.Publisher's Versio

Selfish Herd Optimisation based fractional order cascaded controllers for AGC study

In a modern, and complex power system (PS), robust controller is obligatory to regulate the frequency under uncertain load/parameter change of the system. In addition to this, presence of nonlinearities, load frequency control (LFC) of a Power System becomes more challenging which necessitates a suitable, and robust controller. Single stage controller does not perform immensely against aforesaid changed conditions. So, a novel non-integer/fractional order (FO) based two-stage controller incorporated with 2-degrees of freedom (2-DOF), derivative filter (N), named as 2-DOF-FOPIDN-FOPDN controller, is adopted to improve the dynamic performance of a 3-area power system. Each area of the power system consists of both non-renewable and renewable generating units. Again, to support the superior performance of 2-DOF-FOPIDN-FOPDN controller, it is compared with the result produced by PID, FOPID, and 2-DOF-PIDN-PDN controllers. The optimal design of these controllers is done by applying Selfish Herd Optimisation (SHO) technique. Further, the robustness of the 2-DOF-FOPIDN-FOPDN controller is authenticated by evaluating the system performance under parameter variation. The work is further extended to prove the supremacy of SHO algorithm over a recently published article based on pathfinder algorithm (PFA)

Cell Biology in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease, which affects about 0.33 to 2.65% of the population. In RA Synovium contain various type of immune cell. In which only one cell population cannot cause rheumatoid arthritis that requires more than one cell population. In normal condition, they act as a switch (active or inactive the cell signaling). It controls cell growth, proliferation or metastasizes. In an autoimmune disorder such as rheumatoid arthritis, the immune system mistakenly attacks and destroys the body's cells and tissues. Mostly cells are present in limited numbers in normal human synovium, but in rheumatoid arthritis and other inflammatory joint diseases, this population can expand to constitute 5-20% or more of all synovial cells. Recent investigations in a murine model have demonstrated that cells can have a critical role in the generation of inflammation within the joint. Keyword: Cell Biology in rheumatic arthritis; Dendrite cell; T-cell; Mast cell; Fibroblastic cell; Macrophages cell

Comparison for accurate solutions of nonlinear Hammerstein fuzzy integral equations

In this paper, efficient numerical techniques have been proposed to solve nonlinear Hammerstein fuzzy integral equations. The proposed methods are based on Bernsteinpolynomials and Legendre wavelets approximation. Usually, nonlinear fuzzy integral equations are very difficult to solve both analytically and numerically. The present methods applied to the integral equations is reduced to solve the system of nonlinear algebraic equations. Again, this system has been solved by Newton’s method. The numerical results obtained by present methods have been compared with those of the homotopy analysis method. Illustrative examples have been discussed to demonstrate the validity and applicability of the presented methods

Management practices for west syndrome in south Asia: A survey study and meta-analysis

Objectives: Considering the dearth of literature on West syndrome (WS) from South Asian countries, this study aimed to evaluate the management practices in South Asia by an online survey and meta-analysis.Methods: An online questionnaire was sent to 223 pediatric neurologists/pediatricians in India, Pakistan, Myanmar, Sri Lanka, Bhutan, Nepal, and Bangladesh. Their responses were evaluated and supplemented by a meta-analysis.Results: Of 125 responses received (response rate: 56%), around 60% of responders observed male preponderance and an approximate lead-time-to-treatment (LTTT) of 4-12 weeks. The commonest etiology observed was a static structural insult (88.6% of responders). Most commonly used first-line drug (country-wise) was as follows: India-adrenocorticotropin hormone (ACTH, 50%); Pakistan-oral steroids (45.5%); Myanmar, Sri Lanka, and Nepal-oral steroids (94.4%); Bangladesh-ACTH (2/2); Bhutan-vigabatrin (3/5). ACTH and vigabatrin are not available in Myanmar and Nepal. The most commonly used regime for ACTH was maximal-dose-at-initiation-regime in India, Sri Lanka, and Bangladesh and gradually escalating-regime in Pakistan. Maximum dose of prednisolone was variable-most common response from India: 3-4 mg/kg/d; Pakistan, Bhutan, and Bangladesh: 2 mg/kg/d; Sri Lanka, Nepal, and Myanmar: 5-8 mg/kg/d or 60 mg/d. The total duration of hormonal therapy (including tapering) ranged from 4 to 12 weeks (67/91). Most responders considered cessation of spasms for four weeks as complete response (54/111) and advised electroencephalography (EEG; 104/123) to check for hypsarrhythmia resolution. Difficult access to pediatric EEG in Bhutan and Nepal is concerning. More than 95% of responders felt a need for more awareness. The meta-analysis supported the preponderance of male gender (68%; confidence interval [CI]: 64%-73%), structural etiology(80%; CI 73%-86%), longer LTTT (2.4 months; CI 2.1-2.6 months), and low response rate to hormonal therapy(18% and 28% for ACTH and oral steroids respectively) in WS in South Asia.Significance: This study highlights the practices and challenges in the management of WS in South Asia. These include a preponderance of male gender and structural etiology, a longer LTTT, difficult access to pediatric EEG, nonavailability of ACTH and vigabatrin in some countries, and low effectiveness of hormonal therapy in this region

Investigation of some trace elements in Raipur Industrial area and its surrounding, Raipur District.

The paper deals with determination of eight trace metals namely. Copper, Iron, Mangnese, Zinc, Nickel,, Chromium  Lead and Mercury  in the ground water of different sites of Raipur Industrial area of Raipur district . All activities carried out on the ground surface have direct or indirect impact on the ground water whether associated with urban ,industrial or agricultural activities large scale concentrated source of pollutants, such as industrial discharges and sub surface injection of chemicals and hazardous are obvious source of ground water pollutants. This study was carryout in the month of during summer 2013. The samples were collected from seven different source of Raipur Industrial area of Raipur. The results obtained are compared with safe limits in ppm for heavy metals laid down by BIS, WHO, ICMR, APHA

An important role of coal and its calorific value on the performance of thermal power station: A case study

An investigation was undertaken to study the Physical and Chemical properties of coal in Korba district. Due to the Presence of lot of Coal mines, number of coal based thermal power stations are established in Korba district. So study has been carried out for assessment of coal quality, whether it is suitable for thermal power stations, by collectying sample from Gevra Coal mines. This paper presents Grade of the coal available in Korba district. Three different Coal samples were collected from  different areas of Gevra Coal mines  and analyzed for Proximate, Ultimate and  Calorific value as per Standard methods. The useful heat values (UHV) of three coal samples are 2482K.Cal/Kg, 2917K.Cal/Kg, and 2786K.Cal/Kg. From overall analysis, and according to UHV of coal samples  we can conclude that  the grade of Gevra Coal is” F”and is very much  useful for Coal based thermal power stations