224 research outputs found

    APPLICATION OF HYBRID PSOGA FOR OPTIMAL LOCATION OF SVC TO IMPROVE VOLTAGE STABILITY OF POWER SYSTEM

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    Due to huge increase in power demand, modern power system networks are being operated under highly stressed conditions. This has resulted into the difficulty in meeting reactive power requirement and maintaining the bus voltage within acceptable limits. Voltage instability in the system occurs in the form of a progressive decay in voltage magnitude at some of the buses. The problems of voltage instability and voltage collapse are the major concerns in the operation of power system. It is very important to do the power system analysis with respect to voltage stability. Flexible AC Transmission System (FACTS) device in a power system improves the stability, enhances the voltage stability margin and reduces the power losses. Identification of location of FACTS device in the power system is very important task. Research is carried out to investigate application of Particle Swarm Optimization (PSO), Genetic Algorithm (GA) and hybrid PSOGA to find optimal location and rated value of SVC device to minimize the voltage stability index, total power loss, load voltage deviation, cost of generation and cost of FACTS device to improve voltage stability in the power system. Optimal location and rated value of SVC device have been found for different loading scenario using PSO, GA and PSOGA. It is observed from the results that the voltages stability margin is improved, voltage profile of the power system is increased, load voltage deviation is reduced and real power losses also reduced by optimally locating SVC device in the power system. The proposed algorithm is verified with IEEE 14 bus and 30 bus power system

    Arthrodiastasis in the management of stiff hip

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    Arthrodiastasis (using external fixator and distraction) has been used for various pathologies including deformity correction/stiff hip/slipped capital femoral epiphysis. Historically this has been used for treatment of Perthes disease. The purpose of our study is to evaluate efficacy of arthrodiastasis in management of stiff hip. A 15 year old boy with stiff hip presented with complaints of pain in the left hip for past 6 months. Radiologically the left proximal femur was found to be deformed with metaphyseal widening, sclerosis and arthritic changes. Hip spanning external fixator using limb reconstruction system was done. Distraction was done at a rate of 1 mm/day. After 2 months, fixator was removed. Hip was mobilized under anaesthesia. Good range of all movements was achieved. Arthrodiastasis seems to be a good option in young adolescent in whom total hip replacement needs to be delayed as much as possible

    Role of expression of P63 and calponin in gastro-intestinal tract carcinomas

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    BACKGROUND: Gastrointestinal tract malignancies are causing significant morbidity and mortality constituting 27% of all cancer related deaths worldwide with highest burden of 62% in Asia. In developing countries like India, due to life style modifications and environmental factors the incidence of GIT malignancies are increasing nowadays. P63 and Calponin are the new immunohistochemical markers tried in GIT malignancies and the results were promising. So in our study, the expression of these two immunohistochemical markers were done and correlated with histopathological grading and lymph node status of these cases. OBJECTIVES: 1. To correlate the age, sex and anatomical site of distribution of gastrointestinal tract malignancies. 2. To study the histopathological features of gastrointestinal tract malignancies. 3. To study the role of expression of immunohistochemaical markers P63 and calponin in gastrointestinal tract malignancies. 4. To correlate the histopathological features with expression of immunohistochemical markers P63 and calponin. MATERIALS AND METHODS: A total of 60 cases of gastrointestinal tract carcinomas, 33 cases of GIT biopsies and 27 cases of GIT specimens were taken for the study. The study was conducted for three years (from June 2014 to June 2017). H & E sections and immunohistochemistry was done for the selected blocks of formalin fixed paraffin embedded sections. IHC done by using p63 and calponin for all the cases and the stastical analysis was done to evaluate the prognostic significance of these markers. RESULTS: In the present study, the most common age group involved in gastrointestinal tract malignancies was 61 – 70 years. Males are affected more than females with a sex ratio of 2.33:1. Stomach (antrum) is the most common anatomical site involved in GIT malignancies constituting 36.7% of all the cases followed by rectum with 16%.The most common histopathological diagnosis was adenocarcinoma, constituting around 88% of the total cases and the least common was malignant melanoma with 3.3%. The most common histopathological grade was moderately differentiated carcinomas constituting 36% of total cases (22 cases). The expression of IHC markers p63 and calponin were studied and compared with lymph node status and histopathological grade of tumors and the “p” values were found significant of < 0.05. p63 expression was found to be high in poorly differentiated carcinomas and calponin expression was low in poorly differentiated carcinomas. CONCLUSION: In this study, Increased expression of p63 is directly related to the lymph node metastases and the grade of the tumors. While calponin expression is inversely related to the grade and lymph node status of the cases studied. This study clearly showed that higher expression of calponin inhibits tumor metastases, tumor angiogenesis and tumor invasion, especially in patients with colorectal carcinomas. So targeted therapy with calponin will be prognostically beneficial to the patients with gastrointestinal tract carcinomas. Similarly p63 targeted therapy will be beneficial and improves the survival rate of the patients with gastrointestinal tract malignancies, especially in poorly differentiated esophageal carcinomas, gastric carcinomas and colorectal carcinomas

    Biogas Production Potential of Food Waste

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    At present our country is facing various problems, among that energy crisis has become more serious in next coming years. Both energy crisis and pollution problems could be controlled by adopting an alternative method of biogas production form waste products. Food waste is the best alternative for biogas production in a community level biogas plant. Hence in the present study, an attempt has been made to study the rate of biogas production in a lab scale biogas digester model for the efficient conversion of the food waste (starch –rich materials) generated from PRIST University Campus. The biogas production depends on the maximum biogas yield, the concentration of volatile solids of the input, the density of the effluent, the density of the biogas and the reaction rate constant, which are all substrate - or process - specific. The experiments were carried out for 40 days and the rate of gas production was measured by water displacement method. The pH value of the cow dung and food waste was initially measured and adjusted to nearer to neutral and gradually increased to acidic and again it got stabilised to the neutral pH which favoured the production of biogas. The percentage of total solids was 69.86, 93.56 and 25.67 for cow dung, food waste and digested slurry respectively. The percentage of volatile solids was 52.5, 86.3 and 18.9 for cow dung, food waste and digested slurry respectively. The percentage of volatile fatty acid was 285, 356 and 365 for cow dung, food waste and digested slurry respectively. Observations on daily basis were made on the constituent of biogas, pH, volume and rate of biogas production. The rate of biogas production continuously increased as days progressed and there was maximum yield in biogas after 20 days. Thus continuous feeding helps in daily biogas production and can be used at a small as well as larger scale to manage the organic waste and energy production for various applications

    Green synthesis of silver nanoparticles using Indigofera cordifolia leaf extract and their pharmacological potential

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    Biologically the silver nanoparticles were synthesized from Indigofera cordifolia leaves extract. The absorbance of the silver nanoparticles centered at four hundred and twenty nm, with respect to the surface plasmon resonance of silver nanoparticles wavelength. XRD method proves, biosynthesized NPs would retain the face centered cubic (fcc) structure. In TEM image analysis, silver NPs morphology was spherical in shape. The composition of the silver nanoparticles was obtained by EDAX analysis method. FTIR analysis concluded that biosynthesis Ag NPs was observed at 1384 cm-1, with respect to –NO3 stretching arises from AgNO3. Ten types of bands are present in the broad emission because of organic matrix bound to silver nanoparticles, which reveals as the result of photoluminescence measurements. The silver NPs possess more antibacterial activity as compared to the standard drug, Amoxicillin

    Design of an electrochemical micromachining machine

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    Electrochemical micromachining (μECM) is a non-conventional machining process based on the phenomenon of electrolysis. μECM became an attractive area of research due to the fact that this process does not create any defective layer after machining and that there is a growing demand for better surface integrity on different micro applications including microfluidics systems, stress-free drilled holes in automotive and aerospace manufacturing with complex shapes, etc. This work presents the design of a next generation μECM machine for the automotive, aerospace, medical and metrology sectors. It has three axes of motion (X, Y, Z) and a spindle allowing the tool-electrode to rotate during machining. The linear slides for each axis use air bearings with linear DC brushless motors and 2-nm resolution encoders for ultra precise motion. The control system is based on the Power PMAC motion controller from Delta Tau. The electrolyte tank is located at the rear of the machine and allows the electrolyte to be changed quickly. This machine features two process control algorithms: fuzzy logic control and adaptive feed rate. A self-developed pulse generator has been mounted and interfaced with the machine and a wire ECM grinding device has been added. The pulse generator has the possibility to reverse the pulse polarity for on-line tool fabrication.The research reported in this paper is supported by the European Commission within the project “Minimizing Defects in Micro-Manufacturing Applications (MIDEMMA)” (FP7-2011-NMPICT- FoF-285614)

    Design of a pulse power supply unit for micro-ECM

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    Electrochemical micro-machining (μECM) requires a particular pulse power supply unit (PSU) to be developed in order to achieve desired machining performance. This paper summarises the development of a pulse PSU meeting the requirements of μECM. The pulse power supply provides tens of nanosecond pulse duration, positive and negative bias voltages and a polarity switching functionality. It fulfils the needs for tool preparation with reversed pulsed ECM on the machine. Moreover, the PSU is equipped with an ultrafast overcurrent protection which prevents the tool electrode from being damaged in case of short circuits. The developed pulse PSU was used to fabricate micro-tools out of 170 μm WC-Co alloy shafts via micro-electrochemical turning and drill deep holes via μECM in a disk made of 18NiCr6. The electrolyte used for both processes was a mixture of sulphuric acid and NaNO3 aqueous solutions.The research reported in this paper is supported by the European Commission within the project “Minimizing Defects in Micro-Manufacturing Applications (MIDEMMA)” (FP7-2011-NMP-ICT-FoF-285614
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