Design and Modeling of a Capacitor Bank Power Supply for Fast Charging

Surender Kumar Sharma,Pankaj Deb,R. Shukla,P. Banerjee,T. Prabaharan,R. Das,B. Das,B. Adhikary,A. Shyam 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.61

Power supplies used in pulsed power applications are rugged, and the capacitor bank charges rapidly. The capacitor bank is fully charged to the rated voltage in a minimum time so as to reduce the dielectric stress on the capacitors and to increase their life. When the capacitor bank is discharged in the load much Electromagnetic Interference (EMI) and Electromagnetic Pulse (EMP) due to high currents discharges is generated, which can damage the electronic circuitry in the power supply if proper shielding & isolation are not provided to it. We have designed and fabricated a compact, rugged and low-cost high voltage (HV) power supply for a 114-kJ, 40-kV capacitor bank. The power supply consists of a high voltage transformer (5.25 kVA, 230 V/35 kV, 50 Hz), a high voltage diode (Semikron Make PIV 110 kV, 150 mA) and a charging resistor placed in a tank filled with oil. The charging resistors value is selected after a PSPICE simulation of the charging circuit for different values of the charging resistor. The charging current is limited with the selected resistor so that it does not exceed the current limit of the HV transformer & diode. The input voltage to the high voltage transformer is given through autotransformer, which rotates from 0 ?230 volts in 40 sec with a single-phase synchronous motor. The capacitor bank is charged to 40 kV in a minute after that, the power supply is decoupled from the capacitor bank by using a pneumatic decoupling switch, then the capacitor bank's switch is triggered to deliver the capacitor bank's energy to the load. Control and protection in the power supply is provided for its safe operation. The monitoring of charging voltage is done with a digital display meter with fiber optic isolation by using a V-F and then F-V converter in order to provide electrical isolation.

Establishment of Cryopreservation of Leopard Cat Semen Collected by Electro-ejaculation Method

Ha, A-Na,Jo, A-Ra,Kim, Yu-Gon,Yoon, Jin-Ho,Bang, Jae-Il,Deb, Gautam K.,Fakruzzaman, M.,Lim, Yang-Mook,Yong, Hwan-Yul,Kong, Il-Keun 韓國受精卵移植學會 2011 한국동물생명공학회지 Vol.26 No.4

The aim of this study was to evaluate the post-thawed characteristics of leopard cat semen. In this experiment, semen was collected from two leopard cats (A and B) at wild animal center in Seoul Grand Park in Korea. After collection, the sperms were washed with D-PBS and diluted by the freezing medium (Irvine science, USA) and stored in liquid nitrogen. The post-thawed concentration was for A and for B. The viability of post-thawed sperm from A and B individual was 24.0% and 19.0%, respectively. Pre-freezing motility of A and B individual semen was 68.54% and 56.65. Leopard cat A had more normal sperm than that of B (69.5% vs. 54.5%). Acrosome integrity analysis detected live (14.5% vs. 9.0%), damage (39.0% vs. 44.0%) and dead (46.0% vs. 47.0%) in leopard cat A and B, respectively. The present results concluded that leopard cat semen can be collected successfully by electro-ejaculation method and cryopreserved successfullyfor future use in different assisted reproductive technologies. The cryopreservation protocol needs to be modified for increasing post-thawed viability of leopard cat spermatozoa.

Use of finite and infinite elements in static analysis of pavement

Patil, V.A.,Sawant, V.A.,Deb, Kousik Techno-Press 2010 Interaction and multiscale mechanics Vol.3 No.1

In recent years, study of the static response of pavements to moving vehicle and aircraft loads has received significant attention because of its relevance to the design of pavements and airport runways. The static response of beams resting on an elastic foundation and subjected to moving loads was studied by several researchers in the past. However, most of these studies were limited to steady-state analytical solutions for infinitely long beams resting on Winkler-type elastic foundations. Although the modelling of subgrade as a continuum is more accurate, such an approach can hardly be incorporated in analysis due to its complexity. In contrast, the two-parameter foundation model provides a better way for simulating the underlying soil medium and is conceptually more appealing than the one-parameter (Winkler) foundation model. The finite element method is one of the most suitable mathematical tools for analysing rigid pavements under moving loads. This paper presents an improved solution algorithm based on the finite element method for the static analysis of rigid pavements under moving vehicular or aircraft loads. The concrete pavement is discretized by finite and infinite beam elements, with the latter for modelling the infinity boundary conditions. The underlying soil medium is modelled by the Pasternak model allowing the shear interaction to exist between the spring elements. This can be accomplished by connecting the spring elements to a layer of incompressible vertical elements that can deform in transverse shear only. The deformations and forces maintaining equilibrium in the shear layer are considered by assuming the shear layer to be isotropic. A parametric study is conducted to investigate the effect of the position of moving loads on the response of pavement.

An enhanced numerical procedure for modelling fully grouted bolts intersected by rock joint

Kamal C. Das,Debasis Deb,A.K. Jha 한국자원공학회 2013 Geosystem engineering Vol.16 No.1

The stability of underground structure made especially in jointed rock mass is of the utmost important to designer, engineers and operators. Rock bolting is generally being practised to reinforced excavation walls and roofs by minimizing the movement of rock joints. In this study, a numerical procedure has been developed in extended finite element framework (XFEM) to analyze the behaviour of grouted bolt intersected by a joint. A solid finite element intersected by a bolt and a joint along any arbitrary direction is termed as ‘doubly enriched’ element. Nodes of an doubly enriched element have additional degrees of freedom for determining displacements, stresses developed in the bolt rod as well as the displacements jump and traction along the joint. The paper also provides verifications of this procedure by solving two known examples (i) direct shear test performed on a bolted joint sample-experimental verification and (ii) reinforcement of a joint located in the vicinity of a circular tunnel-analytical verification.

SEPARATION AXIOMS ON BI-GENERALIZED TOPOLOGICAL SPACES

A. Deb Ray,Rakesh Bhowmick 충청수학회 2014 충청수학회지 Vol.27 No.3

In this paper, introducing various separation axioms on a bi-GTS, it has been observed that such separation axioms actually unify the well-known separation axioms on topological spaces. Sev-eral characterizations of such separation properties of a bi-GTS are established in terms of °¹i;¹j -closure operator, generalized cluster sets of functions and graph of functions.

SEPARATION AXIOMS ON BI-GENERALIZED TOPOLOGICAL SPACES

Ray, A. Deb,Bhowmick, Rakesh Chungcheong Mathematical Society 2014 충청수학회지 Vol.27 No.3

In this paper, introducing various separation axioms on a bi-GTS, it has been observed that such separation axioms actually unify the well-known separation axioms on topological spaces. Several characterizations of such separation properties of a bi-GTS are established in terms of ${\gamma}_{{\mu}_i,{\mu}_j}$-closure operator, generalized cluster sets of functions and graph of functions.

Tio₂ Paste Formulation for Crack-Free Mesoporous Nanocrystalline Film of Dye-Sensitized Solar Cells

Sarker, Subrata,Nath, Narayan Chandra Deb,Rahman, Md. Mahbubur,Lim, Sung-Su,Ahammad, A. J. Saleh,Choi, Won-Youl,Lee, Jae-Joon American Scientific Publishers 2012 Journal of Nanoscience and Nanotechnology Vol.12 No.7

<P>Using a doctor-blade method, a highly viscous titanium dioxide (TiO2) paste was deposited on a glass substrate coated with fluorine doped tin oxide (FTO). The paste was mainly composed of commercially available TiO2 nanoparticles (P25) and hydroxypropyl cellulose (HPC) as organic filler. Varying the content of HPC in the TiO2 paste changed the physical properties of the mesoporous TiO2 layer, particularly its porosity and surface area. From the quantification of dyes on Ti2, layer and the electrochemical impedance spectroscopy (EIS) study of the dye-sensitized solar cells (DSSCs), the surface area of the TiO2 film was found to have decreased. This came with the increase of HPC content while the porosity of the film increased, consistent with the concurrent decrease of short-circuit current density (Jsc) and efficiency (eta). The increased porosity greatly affected the electron transport through the TiO2 film by decreasing the coordination number of the TiO2 particles resulting to a decrease of the electron diffusion coefficient.</P>

PREPARATION AND MICROSTRUCTURAL CHARACTERIZATION OF NANOCRYSTALLINE Mn-DOPED ZnO

B. ROY,O. MONDAL,A. DEB,S. P. SENGUPTA,P. CHATERJEE,M. PAL 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2011 NANO Vol.6 No.4

Mn-doped ZnO, a dilute magnetic semiconductor (DMS), has been prepared in nanocrystalline form by using a soft chemical route. The concurrent diffusional growth of both nanocrystalline Mn-doped ZnO and secondary spinel phase ZnMn_2O_4 in annealed samples have been studied by using a modified Rietveld method and transmission electron microscope (TEM). Rietveld analysis reveals that both the compounds start growing when Mn concentration is lower and the volume fraction of crystalline spinel phase ZnMn_2O_4 decreases sharply when Mn concentration increases. TEM study indicates that average particle sizes of both the phases are in nanometer dimensions and are highly crystalline in nature. Magnetization increases initially and then almost saturates with the increase of Mn concentration. The enhanced magnetization could be a combined effect of Mn ions and surface ferromagnetism of nanoparticles.

LABORATORY SIMULATION OF LIGHT SCATTERING FROM REGOLITH ANALOGUES: EFFECT OF POROSITY

KAR, AMRITAKSHA,DEB, SANJIB,SEN, A.K.,GUPTA, RANJAN The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2

The surfaces of most atmosphereless solar system objects are referred to as regolith, layers of loosely connected fragmentary debris, produced by meteorite impacts. Measurements of light scattered from such surfaces provides information about the composition and structure of the surface. A suitable way to characterize the scattering properties is to consider how the intensity and polarization of scattered light depends on the particle size, composition, porosity, roughness, wavelength of incident light and the geometry of observation. In the present work, the effect of porosity on bidirectional reflectance as a function of phase angle is studied for alumina powder with grain size of $0.3{\mu}m$ and olivine powder with grain size of $49{\mu}m$ at 543.5 nm. The optical constants of the alumina sample for each porosity were calculated with Maxwell Garnett effective medium theory. On using each of the optical constants of alumina sample in Mie theory with the Hapke model the variation of bidirectional reflectance is obtained as a function of phase angle with porosity as a parameter. Experimental reflectance data are in good agreement the model. For the olivine sample the effect of porosity is studied using Hapke (2008).

Study on the behavior of beam-column connection in precast concrete structure

Marcela N. Kataoka,Marcelo A. Ferreira,Ana Lúcia H.C. El Debs 사단법인 한국계산역학회 2015 Computers and Concrete, An International Journal Vol.16 No.1

Due to the increase of the use of precast concrete structures in multistory buildings, this paper deals with the behavior of an specific type of beam-column connection used in this structural system. The connection is composed by concrete corbels, dowels and continuity bars passing through the column. The study was developed based on the experimental and numerical results. In the experimental analysis a full scale specimen was tested and for numerical study, a 3D computational model was created using a finite element analyze (FEA) software, called DIANA. The comparison of the results showed a satisfactory correlation between loading versus displacement curves.