Distribution Grid Voltage Regulation for Power Quality Improvement Using UPQC

Poor voltage regulation is experienced for the costumers connected at the end of low voltage distribution grid. In the proposed paper, voltage regulation is achieved in the distribution grid using Unified Power Quality Compensator (UPQC). Different control techniques are used for shunt inverter in UPQC to improve the power quality of the Distribution Grid. Control techniques, including the PI control, DQ control and Minimum Power Point Tracking (mPPT) for voltage control are analyzed and simulated in the proposed paper. Simulation with UPQC is done for three different control techniques and its performances are compared. The mPPT avoids the circulation of unnecessary reactive compensation for voltage regulation by operating at the Minimum Power Point (mPP). Comparative analysis is made for UPQC with the different control techniques during sag, swell and fault condition. The simulation of distribution Grid for voltage regulation using UPQC is carried out using MATLAB Simulink

A Study on Potentiality of Silver as an Investment Asset

In the last few years the countries around the world are facing burden of global economic slowdown and the same is indicated in their slower GDP growth and falling stock market prices. Even under these precarious conditions the commodity markets are experiencing considerable growth and are offering good returns to the investors. Among all commodities, though considered as highly volatile, silver is a very attractive commodity to invest. In contrast to the common belief, silver is relatively a safe investment in the long run and assures significantly high returns to the investors. The present study aims to prove potentiality of silver as an investment asset using simple risk, return analysis and other basic fundamentals. The results of the analysis prove that silver is a good asset for investment vis-à-vis gold and stock markets and is a consistent performer under different economic conditions

DEVELOPMENT AND IN VITRO–IN VIVO EVALUATION OF GASTRORETENTIVE FLOATING TABLETS OF AN ANTIRETROVIRAL AGENT RITONAVIR

Objective: The present research work concerns the development of the extended release of Ritonavir floating matrix tablets, designed to prolong the gastric residence time, increase the drug bioavailability, and diminish the side effects of irritating drugs. Methods: The floating tablets of Ritonavir were prepared by direct compression method using different grades of hydroxypropyl methylcellulose (HPMC), crospovidone, Polyox WSR 303, and sodium bicarbonate, as gas generating agent. Evaluation parameters and in vivo radiographic studies were conducted in suitable model. Results: Among all formulations, F21 was chosen as optimized formulation based on evaluation parameters such as floating lag time (33 s), total floating time (>24 h), and in vitro dissolution studies. From in vitro dissolution studies, the optimized formulation F21 and marketed product were shown 98.67% and 91.46±5.02% of drug release, respectively. The main appliance of medication discharge follows zero-order kinetics and non- Fickian transport by coupled diffusion and erosion. In vivo experiments maintained the potentials in extending the gastric residence time in the fasted state in beagle dogs. The mean gastric residence time of the optimized formulation found to be 330 min±40 in the stomach, where longer gastric residence time is an important condition for prolonged or controlled drug release and also for enhanced bioavailability. Conclusion: From in vitro and in vivo radiographic studies, Ritonavir floating tablets estimated to provide novel choice for harmless, inexpensive, and extended release for the effective management of AIDS

Surface Morphological Studies of Solar Absorber Layer Cu2ZnSnS4 (CZTS) Thin Films by Non-vacuum Deposition Methods

Surface morphological studiesThe consumption of fossil fuel globally has been enormous and has reached an alarming rate resulting in fast depletion of the available resources and at the same time polluting the environment. Hence there is a growing need to take cognizance of abundant amount of inexpensive energy available in the nature especially solar energy. Development and commercialization of Photovoltaics has been in focus due to its low cost, high absorption coefficient and suitable direct band gap for solar energy conversion applications. An attempt has been made in this work to synthesize the CZTS thin films by Electro deposition and Sol-gel method on Indium Tin Oxide (ITO) glass and Soda Lime Glass( SLG) substrates respectively. CZTS thin films have been prepared using a 3-stage electro chemical system wherein the precursors are deposited using platinum foil as a counter electrode and AgCl electrode as a reference electrode and Sol gel method. Surface morphology and optical properties have been studied using Atomic Force Microscopy, Scanning Electron Microscopy, X-ray Diffractometer and UV-Vis Spectroscopy When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3596

Effect of lac treatment on mechanical properties of jute fabric /polyester resin based biocomposite

An attempt has been made to dissolve lac in methanol / sodium hydroxide solution and to use this lac solution as a coupling agent for jute fabric. Lac treated jute fabric has been used to reinforce the unsaturated polyester resin (USP). Flexural strength and inter-laminar shear strength (ILSS) of lac modified jute/USP biocomposite have been evaluated and then compared with sodium hydroxide treated jute as well as untreated jute based biocomposites. Lac treated jute fabric shows higher flexural properties of the biocomposite than that of untreated jute fabric, which infers that lac acts as a good compatibliser between jute fibre and USP. Lac treatment on jute fabric enhances the flexural properties of biocomposite better in alkaline medium than in solvent medium. It is concluded that lac treatment can be used to improve the flexural and ILSS properties of jute / thermoset resin based biocomposite

OPTIMIZATION OF MEDIUM COMPONENTS FOR ANTIBACTERIAL METABOLITE PRODUCTION FROM MARINE STREPTOMYCES SP. PUA2 USING RESPONSE SURFACE METHODOLOGY

Objective: The present study is an attempt to optimize the fermentation conditions for the antibacterial compound production from a newly isolated marine Streptomyces strain PUA2 by adopting response surface methodology as the statistical tool. Methods: Prior to using the Response Surface Methodology, Plackett Burmann (PB) design was used to explore the effect of variables on the antibacterial compound production. In PB method, high and low values were assigned for the eight variables viz., glucose, glycerol, soybean meal, manganese chloride, calcium carbonate, peptone and pH. Calcium carbonate and peptone were used as dummy variables. Based on the results of combined effects glycerol, soybean meal, manganese chloride and pH were investigated by 24 full-factorial central composite design. Results: The results of PB method showed the significant effect of glycerol, soybean meal, manganese chloride and pH on the antibacterial compound production. The results of ANOVA and regression of second order model showed that the linear effects of glycerol and manganese chloride and cross products effects of manganese chloride and pH were more significant. All the critical variables having greatest effect on the production of antibacterial compound from marine Streptomyces species PUA2. Optimization of process parameters resulted in increase in antibacterial activity from 7 mm to 14 mm. Conclusion: The factors optimized in the present study were useful for the increased production of antibacterial metabolite from Streptomyces sp PUA2. The result confirms the feasibility of medium optimization to improve antibiotic production

Thermal Performance of Screen Mesh Wick Cylindrical Heat Pipe using Al 2 O 3 Nanofluid

ABSTRACT: In this research, the effect of using aluminum oxide Nanofluid (pure water mixed with Al 2 O 3 nanoparticle With 35 nm diameter) on the thermal efficiency enhancement of a heat pipe on the different operating state was investigated. The heat pipe was made of a straight copper tube with an outer diameter of 8mm and length 190 mm and stainless steel of 1mm wick-thickness for heat pipe. In the heat pipe tube, there is a 90° curve between the evaporator and condenser sections. The tested concentration levels of Nanofluid are 0%, 1% and 3%wt. Results show that by charging the Nanofluid to the heat pipe, thermal performance is enhanced by reducing the thermal resistance and wall temperature difference. The thermal efficiency of heat pipe charged with Nanofluid is compared with pure water