1,384 research outputs found

    Performance comparison of hybrid active power filter for p-q theory and SVPWM technique

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    Harmonic Distortion in many of the industrial applications are occur primarily owing to the enormous utilization of loads with high non-linearity like power converters, speed varying drives and arc furnaces. The power semiconductor is used to achieve the variation in speed and conversion from one source to another. Mostly active filters and tuned filters are utilized to remove the harmonic included in the source current. The tuned passive filters and inductance inserted in the line reduces the harmonics but at the same time induces the resonances in most of the industrial applications. Due to this, harmonic distortion increases in the source current and voltage. This can be reduced by adding hybrid filter in the system with decreased rating of active filter in high power applications. This article deals with the various topology of hybrid filters. The working of the proposed filter design in variable inductance mode based on the pollution created in the source voltage and current is studied. In the proposed hybrid filter passive filter is tuned with seventh harmonic frequency and connected in series with active filters to reduce the harmonic distortion. DC link voltage and the active filter VA rating could be minimized. The control signal to the filter is derived from p-q theory and space vector pulse width modulation (SVPWM). The performance of the system under study is simulated and noted for the THD percentage before and after the filter is added to the system and the same model is experimented with reduced voltage level

    1-{3-[(4-Oxopiperidin-1-yl)carbon­yl]benzoyl}piperidin-4-one

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    Two independent mol­ecules comprise the asymmetric unit in the title compound, C18H20N2O4. One of the mol­ecules exhibits disorder in one of its 4-piperidone rings, which is disposed over two orientations [site occupancy of the major component = 0.651 (5)]. The first independent mol­ecule and the minor component of the second disordered mol­ecule are virtually superimposable. The central four C atoms in the major component of the disordered mol­ecule have an opposite orientation. All the 4-piperidone rings have a chair conformation. The carbonyl groups in each mol­ecule have approximate anti conformations [O=C⋯C=O = 146.2 (2) and −159.9 (2)°]. The 4-piperidone rings lie to opposite sides of the central benzene ring in both mol­ecules. In the crystal, mol­ecules are linked by C—H⋯O inter­actions. The crystal studied was found to be a non-merohedral twin (twin law −1 0 0, 0 1 0, 0 − 1/2 − 1), the fractional contribution of the minor component being approximately 11%

    Deferring the learning for better generalization in radial basis neural networks

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    Proceeding of: International Conference Artificial Neural Networks — ICANN 2001. Vienna, Austria, August 21–25, 2001The level of generalization of neural networks is heavily dependent on the quality of the training data. That is, some of the training patterns can be redundant or irrelevant. It has been shown that with careful dynamic selection of training patterns, better generalization performance may be obtained. Nevertheless, generalization is carried out independently of the novel patterns to be approximated. In this paper, we present a learning method that automatically selects the most appropriate training patterns to the new sample to be predicted. The proposed method has been applied to Radial Basis Neural Networks, whose generalization capability is usually very poor. The learning strategy slows down the response of the network in the generalisation phase. However, this does not introduces a significance limitation in the application of the method because of the fast training of Radial Basis Neural Networks

    Electronic Theses and Dissertations and Academia: A Preliminary Study From India

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    This paper outlines the current state of doctoral theses collections in India, their usage, problems with access, and the academic and research community’s attitude towards digital archiving and electronic publishing in Indian universities

    Bioreduction of silver nanoparticles from aerial parts of Euphorbia hirta L. (EH-ET) and its potent anticancer activities against neuroblastoma cell lines

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    Euphorbia hirta L. (Family: Euphorbiaceae) is a versatile medicinal plant and enriched with novel bioactive molecules and possess broad-spectrum pharmacological actions. Present work is aiming to synthesis and characterize of silver nanoparticles (AgNPs) by bioreduction method an using ethanolic extract of aerial parts of Euphorbia hirta L. (EH-ET). The synthesized AgNPs observed by a color change of source solution (as AgNPs) and further confirmed by the UV-Visible spectroscopic technique. The AgNPs synthesized were characterized by Scanning Electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and Zeta potential analysis. The synthesized AgNPs are polydispersed and some places it’s agglomerated. The particle size EH-ET silver nanoparticles were analyzed using Beckman coulter particle size analyzer (DelsaTM Nano common). The average size of the particles size noted in 2.9-206.3 nm. Anticancer activity of EH-ET Silver nanoparticles was tested against neuroblastoma cells (SH-SY5Y) and breast cancer cells (SH-SY5Y) and cytotoxicity were tested in vero cells by MTT assay. The preliminary confirmation of the synthesized AgNPs by the present method was made by the appearance of reddish brown color and the visible absorption peak at 429.5 nm. SEM image revealed that AgNPs synthesized were spherical in shape and silver nanoparticles were in the size range of 2.9 to 206.3 nm. FT-IR spectra showed the peaks corresponding to functional groups C=O, -C=C and -OH, which actively participated in bio-reduction and subsequent stabilization reactions in the synthesis of AgNPs. The obtained nanoparticles showed promising anticancer activity against neuroblastoma cells (SH-SY5Yc) and breast cancer cells (MCF-7) with IC50 values of 29.85 and 335 µg/mL, respectively. Whereas, the nanoparticles did not show any activity against vero cell lines. The synthesized silver nanoparticles using an ethanolic extract of Euphorbia hirta L. would be helpful for the preparation of potent cytotoxicity agents to destroy cancer cells

    Association of DNA damage and dyslipidemia with polycystic ovarian syndrome

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    Polycystic ovary syndrome (PCOS) is associated with hyperinsuli-nemia and insulin resistance which may lead to cardiovascular diseases. Evidence for cardiovascular events in women who were affected by PCOS during fertile age is limited. The pathogenesis is unknown; however, it is a complex multigenetic disorder. The present study was undertaken to evaluate the various cardiovas-cular risk factors and their DNA repair efficiency in women with PCOS by investigating the biochemical, endocrinological and mo-lecular cytogenetic alterations. These investigations were carried out in 116 women in the age group of 15-35 years clinically diag-nosed with PCOS. Data were compared with that of 50 age-matched healthy normal women. Fasting blood sugar (FBS), Lipid profile, Follicle-Stimulating Hormone (FSH) and Luteinizing Hor-mone (LH), Prolactin and Estradiol were estimated after getting the informed consent. Mutagen induced chromosome sensitivity analysis was carried out in the lymphocytes of the subjects to as-sess the DNA repair proficiency. Fasting Blood Sugar, total cho-lesterol and LDL cholesterol were found to be elevated whereas HDL cholesterol was found to be lowered in the test subjects. FSH, LH and prolactin were also found to be significantly elevated in the test subjects. Change in the estradiol concentration in the test subjects was not significant. The mutagen sensitivity analysis revealed a significant elevation in break per cell (b/c) values indi-cating a deficiency in the DNA repair mechanism / DNA damage in PCOS patients. Modification of life style by changing the dietary habit and sedentary life style will help to reduce the oxidative stress and may increase the ovarian function and a sensible life-style management is recommended for reducing the risk for CVD

    Optimization of Drilling Process Parameters on Die Steel (H13) using Carbide Coated Drill by Design of Experiment Concept

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    This experimental work presents the optimization of process parameter of surface roughness with using coated carbide drill on H13 steel. Taguchi design of experiments was implemented for executing the process parameter of Drilling process on H13 steel plates. The drilling parameters including 2 Factors such as spindle speed (rpm) and feed rate (mm/min) are optimized using response performance characteristic of surface roughness of H13 die steel plates.H13 steel play an important role in many applications such as Shaft, axle, gears and fasteners due to their strength to weight ratio. The process parameters of spindle speed and feed rate are influenced by machining accuracy during drilling process. The main objectives of experimental works have been identified by lower roughness during drilling process of H13 steel plates. Orthogonal array (L16) of Taguchi Design of experiments and Analysis of Variance (ANOVA) are utilized to analyze the effect of drilling parameters on Quality of drilled holes. The result of experiments indicate is a dominating parameter of surface roughness of H 13 steel plates in Drilling process

    Electronic Theses and Dissertations and Academia: A Preliminary Study From India

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    This paper outlines the current state of doctoral theses collections in India, their usage, problems with access, and the academic and research community’s attitude towards digital archiving and electronic publishing in Indian universities

    1-[2,4,6-Trimethyl-3,5-bis­(4-oxopiperidin-1-ylmeth­yl)benz­yl]piperidin-4-one

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    In the structure of the title compound, C27H39N3O3, each of the (4-oxopiperidin-1-yl)methyl residues adopts a flattened chair conformation (with the N and carbonyl groups being oriented to either side of the central C4 plane) and they occupy positions approximately orthogonal to the central benzene ring [Cbenzene—C—Cmethyl­ene—N torsion angles 103.4 (2), −104.4 (3) and 71.9 (3)°]; further, two of these residues are oriented to one side of the central benzene ring with the third to the other side. In the crystal packing, supra­molecular layers in the ab plane are sustained by C—H⋯O inter­actions

    Heavy Metal Concentrations in Three Commercial Fish Species in Cuddalore Coast, Tamil Nadu, India

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    Three fish species samples were collected from Cuddalore along Tamil Nadu coast, Bay of Bengal, India were analyzed for the levels of heavy metals to elucidate the status of the contamination in fish meat for human consumption. Concentrations of Cu, Cr, Cd, Co, Ni and Zn were determined for the above species using Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES). The concentrations of heavy metal in the samples were below the maximum residual level recommended by various organizations. Therefore, the fish muscles of the samples analyzed were fit for human consumption in this region
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