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Search Results: 1 - 10 of 24481 matches for " Ashutosh;Pradip Kumar Jain "
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FDTD Analysis of the Dispersion Characteristics of the Metal PBG Structures
Ashutosh;Pradip Kumar Jain
PIER B , 2012, DOI: 10.2528/PIERB11120601
Abstract: Two dimensional metallic photonic band gap (PBG) structures, which have higher power handling capability, have been analyzed for their dispersion characteristics. The analysis has been performed using finite difference time domain (FDTD) method based on the regular orthogonal Yee's cell. A simplified unit cell of triangular lattice PBG structure has been considered for the and modes of propagation. The EM field equations in the standard central-difference form have been taken in FDTD method. Bloch's periodic boundary conditions have been used by translating the boundary conditions along the direction of periodicity. For the source excitation, a wideband Gaussian pulse has been used to excite the possible modes in the computational domain. Fourier transform of the probed temporal fields has been calculated which provides the frequency spectrum for a set of wave vectors. The determination of eigenfrequencies from the peaks location in the frequency spectrum has been described. This yields the dispersion diagram which describes the stop and pass bands characteristics. Effort has been made to describe the estimation of defect bands introduced in the PBG structures. Further, the present orthogonal FDTD results obtained have been compared with those obtained by a more involved non-orthogonal FDTD method. The universal global band gap diagrams for the considered metal PBG structure have been obtained by varying the ratio of rod radius to lattice constant for both polarizations and are found identical with those obtained by other reported methods. Convergence of the analysis has been studied to establish the reliability of the method. Usefulness of these plots in designing the devices using 2-D metal PBG structure has also been illustrated.
Multimode Behavior of a 42ghz, 200kw Gyrotron
Ashutosh;B. Ravi Chandra;Pradip Kumar Jain
PIER B , 2012, DOI: 10.2528/PIERB12050905
Abstract: The multimode beam wave interaction behavior in a tapered, cylindrical cavity RF interaction structure of a 42 GHz gyrotron operating in the mode has been investigated through nonlinear analysis and PIC simulation. A technique for producing the annular gyrating electron beam in PIC simulation code CST Particle Studio has been described. An energy transfer phenomenon from electron beam to RF has been demonstrated. The performance of cavity has been monitored to ensure the device operation in the desired mode and frequency. In the PIC simulation, the effect of beam velocity spread on the power output has been discussed. Using multimode behaviour, the effect of presence of nearby modes on the cavity performance has been observed. The simulation results have been compared with the results obtained from self-consistent single-mode analysis and time-dependent multimode analysis. It has been found that output power is well above the desired 200 kW level for the designed 42 GHz gyrotron operating in mode.
Solar Cells: In Research and Applications—A Review  [PDF]
Shruti Sharma, Kamlesh Kumar Jain, Ashutosh Sharma
Materials Sciences and Applications (MSA) , 2015, DOI: 10.4236/msa.2015.612113
Abstract: The light from the Sun is a non-vanishing renewable source of energy which is free from environmental pollution and noise. It can easily compensate the energy drawn from the non-renewable sources of energy such as fossil fuels and petroleum deposits inside the earth. The fabrication of solar cells has passed through a large number of improvement steps from one generation to another. Silicon based solar cells were the first generation solar cells grown on Si wafers, mainly single crystals. Further development to thin films, dye sensitized solar cells and organic solar cells enhanced the cell efficiency. The development is basically hindered by the cost and efficiency. In order to choose the right solar cell for a specific geographic location, we are required to understand fundamental mechanisms and functions of several solar technologies that are widely studied. In this article, we have reviewed a progressive development in the solar cell research from one generation to other, and discussed about their future trends and aspects. The article also tries to emphasize the various practices and methods to promote the benefits of solar energy.
Low Area FSM based Programmable BIST
Neha Namdev,,Rita Jain, Ashutosh kumar Singh
International Journal of Computer Technology and Electronics Engineering , 2011,
Abstract: This paper presents a FSM based Programmable Built-In Self-Test (BIST) approach for testing memory modules in SOC(system on chip) The BIST can be flexible and selectable on-line by selection command so a test algorithm from predetermined set of algorithms that are built in the memory BIST ,can be used Thus, the proposed scheme supports the various memory test algorithms to test different types of memory modules in SOC..In general, there are a variety of heterogeneous memory modules in SOC, and it is not possible to test all of them with a single algorithm. Thus, the proposed scheme greatly simplifies the testing process. Besides, the proposed is more efficient in terms of circuit size and test data to be applied, and it requires less time to configure the BIST. We also develop a programmable memory BIST generator that automatically produces RTL model of the proposed BIST architecture for a given set of test algorithms.
Analysis of a Coaxial Waveguide Corrugated with Wedge-Shaped Radial Vanes Considering Azimuthal Harmonic Effects
Kalpana Singh;Pradip Kumar Jain;B. N N. Basu
PIER , 2004, DOI: 10.2528/PIER04010201
Abstract: The analysis was developed for a coaxial waveguide for two configurations - one in which the central conductor is corrugated in axial slot-wedges, with ridge-wedges between them, and the other in which the outer conductor is provided with radial metal vane-wedges. Azimuthal harmonics were considered in the structure regions, the effects of which were ignored in earlier published analyses based on the surface impedance model to replace the interface between the two structure regions by a homogeneous reactive surface. For both the structure configurations, one and the same form of the dispersion relation with proper interpretation of the symbol for the radius of the ridge/vane was obtained. The dispersion relation obtained by the present analysis was validated against that obtained by other analytical methods reported in the literature. The shape of the dispersion characteristics is found uncontrollable by the structure parameters, and therefore the structure cannot be used for broadbanding a gyro-TWT. However, the plot of the eigenvalue versus the ratio of the outer conductor to ridge/vane radii strongly depended on the ridge/vane parameters. Thus the structure with its cross section tapered and ridge/groove parameters optimized has the potential for providing mode rarefaction in high-power, over-sized, over-moded gyrotrons.
Design and Implementation of High Performance AHB Arbiter for on chip Bus Architecture
International Journal of Engineering Science and Technology , 2011,
Abstract: Resolution is a big issue in SOC( system On Chip) while dealing with number of master trying to sense a single data bus . The ffectiveness of a system to resolve this priority resides in its ability to logical assignment of the chance to transmit data width of the data, response to the interrupts etc. The purpose of this paper is to propose the scheme to implement such a system using the specification of AMBA bus protocol .The scheme involves the typical AMBA features of ‘single clock edge transition ‘, Split transaction ‘,’several bus masters ‘, ‘burst transfer ’.The bus arbiter ensures that only one bus master at a time is allowed to initiate data ransfers. Even though the arbitration protocol is fixed, any arbitration algorithm, such as highest priority or fair access can be implemented depending on the application requirements .The design architecture is written using VHDL(Very High Speed Integrated CircuitsHardware Description Language) code using Xilinx ISE Tools .The architecture is modeled and synthesized using RTL(Register Transfer Level) abstraction and Implemented on Virtex2 series.
A Simple Analysis of Helical Slow-Wave Structure Loaded by Dielectric Embedded Metal Segments for Wideband Traveling-Wave Tubes
R. Seshadri;Sanjay Kumar Ghosh;A. Bhansiwal;S. Kamath;Pradip Kumar Jain
PIER B , 2010, DOI: 10.2528/PIERB10031201
Abstract: A simple field analysis was developed for helical slow-wave structure symmetrically supported by rectangular shaped discrete dielectric support rods partially embedded in the metal segments projecting radially inward from a metal envelope for wideband traveling-wave tubes. The tape helix model was used for the prediction of the dispersion relation and the interaction impedance characteristics. The closed form simplified expressions are obtained by combining the tape model dispersion relation for free-space helix and the dielectric loading factor obtained for the loaded helix in the sheath model. The dispersion characteristics and the interaction impedance characteristics obtained by the present analysis were compared with other more involved analytical method reported in the literature for the similar helical slow-wave structure and found to be in close agreement. The present analytical results were also validated against HFSS simulation with an agreement within 5% for both the characteristics for a wide range of structure parameters. An appropriate choice of the structure parameters (helix thickness, height of the metal segments, material of the dielectric support rods, wedge segments angle and helix pitch) provided the phase velocity varying with frequency corresponding to flat to negative structure dispersion with an appreciable interaction impedance values over a wide frequency band. The present analysis enjoys simplicity and establishes the potential of theproposed helical interaction structure for its employment in wideband traveling-wave tubes.
Synthesis, characterization and pharmacological evaluation of amide prodrugs of Flurbiprofen
Mishra, Ashutosh;Veerasamy, Ravichandran;Jain, Prateek Kumar;Dixit, Vinod Kumar;Agrawal, Ram Kishor;
Journal of the Brazilian Chemical Society , 2008, DOI: 10.1590/S0103-50532008000100014
Abstract: flurbiprofen (fb) suffers from the general side effects of nsaids, owing to presence of free carboxylic acid group. the study was aimed to retard the adverse effects of gastrointestinal origin. ten prodrugs of fb were synthesized by amidation with ethyl esters of amino acids, namely, glycine, l-phenylalanine, l-tryptophan, l-valine, l-isoleucine, l-alanine, l-leucine, l-glutamic acid, l-aspartic acid and b alanine. purified synthesized prodrugs were characterized by m.p., tlc, solubility, partition coefficients, elemental analyses, uv, ftir, nmr and ms. synthesized prodrugs were subjected for bioavailibility studies, analgesic, anti-inflammatory activities and ulcerogenic index. marked reduction of ulcerogenic index and comparable analgesic, anti-inflammatory activities were obtained in all cases as compared to fb. among synthesized prodrugs ar-9, ar-10 and ar-2 showing excellent pharmacological response and encouraging hydrolysis rate both in (simulated intestinal fluid) sif and in 80% human plasma. prodrugs with increased aliphatic side chain length or introduction of aromatic substituent resulted in enhanced partition coefficient but diminished dissolution and hydrolysis rate. such prodrugs can be considered for sustained release purpose.
Path space as manifold, manifold of maps, infinite dimensional manifold
Pradip Kumar
Mathematics , 2011,
Abstract: Let $M$ be any $n$ dimensional smooth manifold and $PM$ be the space of all smooth paths, then we showed that $PM$ is a smooth manifold modelled over a complete normable space. We discussed many geometric structure on Path spaces and its relation to ambient space.
Darboux chart on Projective limit of weak symplectic Banach manifold
Pradip Kumar
Mathematics , 2013,
Abstract: Suppose M be the projective limit of weak symplectic Banach manifolds \{(M_i,\phi_{ij})\}_{i,j\in\mathbb N}, where M_i are modeled over reflexive Banach space and \sigma is compatible with the inverse system(defined in the article). We associate to each point x\in M, a Fr\'{e}chet space H_x(defined in section 3). We prove that if H_x are locally constant, then with certain smoothness and boundedness condition, there exists Darboux chart for the weak symplectic structure.
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