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Search Results: 1 - 10 of 462176 matches for " Vijendra A. Chaudhari "
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Synthesis, Structural, and Electrical Properties of Pure PbTiO3 Ferroelectric Ceramics
Vijendra A. Chaudhari,Govind K. Bichile
Smart Materials Research , 2013, DOI: 10.1155/2013/147524
Abstract: Single-phase polycrystalline samples of lead titanate with perovskite structure have been synthesized using solid-state reaction technique. The processing parameters have been optimized to obtain phase pure, dense, crack-free, and homogeneous samples. The sintering behavior of PT-powders has been investigated using X-ray diffraction patterns. The X-ray powder diffraction data have been analyzed to confirm the phase formation and phase purity, to obtain unit cell parameters and unit cell volume. The porosity of the samples has been obtained through X-ray density and bulk density. The average particle sizes of the phase pure samples were obtained from the X-ray peak width using Scherrer’s formula. The influence of sintering temperature and time on the microstructure of samples has also been studied by carrying out SEM investigations. The notable feature of this microstructure study shows that the samples sintered at 900°C for 12 hours possess a fairly uniform grain distribution. The electrical behavior (complex impedance Z*, complex permittivity ε*, etc.) of the samples sintered at 900°C for 12 hours has been studied by complex impedance spectroscopy. The temperature variation of real permittivity gives evidence of the ferroelectric phase transition as well as of the relaxation behavior. 1. Introduction Crystals of the perovskitefamily, such as PbTiO3, BaTiO3, SrTiO3 and, have been of constant interest because some ofthese materials show ferroelectric behavior and undergo structural phase transitions [1]. PbTiO3 has been considered to be one of the most important members of this family. It has a high Curie temperature, high pyroelectric coefficient, low dielectric constant, and high spontaneous polarization [2]. Lead titanate (PbTiO3, PT) is a ferroelectric ceramic that has not been proved to be a technologically important material by itself but is a significant component material in electronics such as capacitors, ultrasonic transducers, thermistors, and optoelectronics [3–7]. It is also a promising material for pyroelectric infrared detector applications because of its large pyroelectric coefficient and relatively low permittivity [8, 9]. PbTiO3 (PT) has also been extensively used in a range of piezoelectric applications, as well as being the end member of technologically significant ferroelectric perovskite series such as PbZr(x)Ti(1?x)O3 (PZT), Pb(x)Ca(1?x)TiO3, Pb(Zn1/3Nb2/3)O3-(x) PbTiO3 (PZN-PT), and Pb (Mg1/3Nb2/3) O3-(x) PbTiO3 (PMN-PT) and so forth. At ambient temperature, the material has a strong anisotropy which develops during cooling
Synthesis and Electrical Characterization of BaTiO3 Thin Films on Si(100)  [PDF]
V. R. Chinchamalatpure, S. A. Ghosh, G. N. Chaudhari
Materials Sciences and Applications (MSA) , 2010, DOI: 10.4236/msa.2010.14029
Abstract: BaTiO3 thin film has been deposited on Si(100) substrate using sol-gel process and deposited by using spin – coating technique. The BaTiO3/Si(100) structures were studied by structural and electrical characteristics. The X-ray diffrac-tion of BaTiO3/Si(100) shows that the diffraction peaks become increasing sharp with increasing calcination tempera-tures indicating the enhance crystallinity of the films. Scanning electron microscopy of BaTiO3 thin films shows the crack free and uniform nature. The capacitance-voltage measurement of BaTiO3 thin film deposited on Si(100) an-nealed at 600℃ shows large frequency dispersion in the accumulation region. The current-voltage measurement of BaTiO3/Si shows the ideality factor was approaches to unity at 600℃.
Efficient Clustering for High Dimensional Data: Subspace Based Clustering and Density Based Clustering
Singh Vijendra
Information Technology Journal , 2011,
Abstract: Finding clusters in a high dimensional data space is challenging because a high dimensional data space has hundreds of attributes and hundreds of data tuples and the average density of data points is very low. The distance functions used by many conventional algorithms fail in this scenario. Clustering relies on computing the distance between objects and thus, the complexity of the similarity models has a severe influence on the efficiency of the clustering algorithms. Especially for density-based clustering, range queries must be supported efficiently to reduce the runtime of clustering. The density-based clustering is also influenced by the density divergence problem that affects the accuracy of clustering. If clusters do not exist in the original high dimensional data space, it may be possible that clusters exist in some subspaces of the original data space. Subspace clustering algorithms localize the search for relevant dimensions allowing them to find clusters that exist in multiple, possibly overlapping subspaces. Subspace clustering algorithms identifies such subspace clusters. But for clustering based on relative region densities in the subspaces, density based subspace clustering algorithms are applied where the clusters are regarded as regions whose densities are relatively high as compared to the region densities in a subspace. This study presents a review of various subspaces based clustering algorithms and density based clustering algorithms with their efficiencies on different data sets.
ELEVATION OF SERUM C-REACTIVE PROTEIN AND S100 PROTEINS FOR SYSTEMIC INFLAMMATION IN AUTISTIC CHILDREN
Vijendra SINGH
Journal of Special Education and Rehabilitation , 2005,
Abstract: The pathogenesis of autism, a neurological disorder severely affecting young children, may involve inflammation and autoimmunity. In this report, the distribution of acute-phase C-reactive protein (CRP) and S100 proteins was examined in normal and autistic children. Their serum levels were measured by enzyme-linked immunosorbent assay (ELISA). Autistic children were found to have significantly higher than normal levels of CRP (p=0.005) and S100 proteins (p=0.03). The existence of elevated levels of CRP and S100 proteins in autistic children is an excellent sign of systemic inflammation that may contribute to the neuropathology of this brain disorder.
From 1 Sun to 10 Suns c-Si Cells by Optimizing Metal Grid, Metal Resistance, and Junction Depth
Vikrant A. Chaudhari,Chetan S. Solanki
International Journal of Photoenergy , 2009, DOI: 10.1155/2009/827402
Abstract: Use of a solar cell in concentrator PV technology requires reduction in its series resistance in order to minimize the resistive power losses. The present paper discusses a methodology of reducing the series resistance of a commercial c-Si solar cell for concentrator applications, in the range of 2 to 10 suns. Step by step optimization of commercial cell in terms of grid geometry, junction depth, and electroplating of the front metal contacts is proposed. A model of resistance network of solar cell is developed and used for the optimization. Efficiency of unoptimized commercial cell at 10 suns drops by 30% of its 1 sun value corresponding to resistive power loss of about 42%. The optimized cell with grid optimization, junction optimization, electroplating, and junction optimized with electroplated contacts cell gives resistive power loss of 20%, 16%, 11%, and 8%, respectively. An efficiency gain of 3% at 10 suns for fully optimized cell is estimated.
Web Data Extraction for Developing a Mashup
Poonam. A. Chaudhari,Rahul. L. Paikrao
Lecture Notes in Engineering and Computer Science , 2012,
Abstract:
Content Based Image Retrieval Using Color and Shape Features
RESHMA CHAUDHARI,A.M.PATIL
International Journal of Advanced Research in Electrical, Electronics and Instrumentation Engineering , 2013,
Abstract: Content-Based Image Retrieval (CBIR) uses the visual contents of an image such as color, shape, texture, and spatial layout to represent and index the image. Active research in CBIR is geared towards the development of methodologies for analyzing, interpreting cataloging and indexing image databases. In addition to their development, efforts are also being made to evaluate the performance of image retrieval systems. The quality of response is heavily dependent on the choice of the method used to generate feature vectors and similarity measure for comparison of features. In this paper we proposed an algorithm which incorporates the advantages of various other algorithms to improve the accuracy and performance of retrieval. The accuracy of color histogram based matching can be increased by using Color Coherence Vector (CCV) for successive refinement. The speed of shape based retrieval can be enhanced by considering approximate shape rather than the exact shape. In addition to this a combination of color and shape based retrieval is also included to improve the accuracy of the result.
ARTIFICIAL NEURAL NETWORK CONTROLLER FOR PERFORMANCE OPTIMIZATION OF SINGLE PHASE INVERTER
Shubhangi S. Ambekar,Madhuri A. Chaudhari
International Journal of Artificial Intelligence & Applications , 2012,
Abstract: Thyristorised Power control provides high efficiency. However, generated harmonics cause a nuisance inpower system operation. The work presented here, deals with reduction of harmonics (3rd-11th) by usingMultiple Pulse Modulation technique. Traditional numerical methods do not yield accurate pulse-positionsas non-linearity is involved in computation. In this paper, a continuous Hopfiled Neural Network isdesigned for Harmonic minimization in a 1 inverter output voltage. Results show considerableimprovement in voltage spectrum if trigger pulses are generated at the ANN positions as harmonic contentsare reduced with significant improvement in fundamental voltage resulting in reduction in device ratings.The ANN controlled voltage is used to drive a 1 Induction motor in MATLAB simulation and is comparedwith SPWM controlled VSI driving the same motor load. The quantitative analysis is given in tabular form.This shows feasibility of design of a controller for optimized performance of a single phase VSI.
Successful management of spontaneous pneumothorax during general anaesthesia in a patient with eosinophilia.
Shah K,Shetty A,Chaudhari L
Journal of Postgraduate Medicine , 1998,
Abstract: A 10-year-old male patient posted for left elbow arthrolysis developed pneumothorax during general anaesthesia. He had history of upper respiratory tract infection and high eosinophil count, which remained high in spite of treatment. In such patients, it is advisable to use steroid pre-operatively & intraoperatively to produce transient eosinopenia so that complications of eosinophilia are avoided.
Use of nitroglycerin ointment to prevent hypertensive response during electroconvulsive therapy--a study of 50 cases.
Parab A,Chaudhari L,Apte J
Journal of Postgraduate Medicine , 1992,
Abstract: Fifty patients of either sex, aged between 20 and 60 years undergoing electroconvulsive therapy were included in our study. Each patient was used as his/her own control. We observed the cardiovascular changes without nitroglycerin ointment in the first sitting and in the next sitting with the application of 2 inches of 2% nitroglycerin ointment 45 min before the electroconvulsive therapy. Arterial blood pressure and heart rate increase during electroconvulsive therapy can be effectively attenuated by application of 2 inches of 2% nitroglycerin ointment 45 min before the electroconvulsive therapy (p < 0.001 and p < 0.01 resp.). This may be especially beneficial for patients who are at increased risk of myocardial ischemia and stroke.
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