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Search Results: 1 - 10 of 223840 matches for " R. Podder "
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Structural and Optical Properties of Triglycine Sulfate Single Crystals Doped with Potassium Bromide  [PDF]
Farhana Khanum, Jiban Podder
Journal of Crystallization Process and Technology (JCPT) , 2011, DOI: 10.4236/jcpt.2011.12005
Abstract: Triglycine sulfate crystal and potassium bromide doped triglycine sulfate crystals were grown from aqueous solution by slow evaporation method. Energy dispersive X-ray analysis identifies the elements present in the crystal. The Fourier Transform Infrared spectroscopy has been recorded in the range 400 to 4000 cm-1 and the functional groups of the grown crystals have been identified. The structural studies on the grown crystals were carried out by X-ray diffraction analysis technique and found that the grown crystal crystallizes in monoclinic structure. The lattice cell parameters of pure Triglycine sulfate are a = 9.6010 Å, b = 12.5600 Å, c = 5.4500 Å. Ultraviolet-Visible spectra show that the grown crystals have wide optical transparency in the entire visible region.
Structural, Optical, Electrical and Thermal Characterizations of Pure and L-alanine Doped Ammonium Dihydrogen Phosphate Crystals  [PDF]
Ferdousi Akhtar, Jiban Podder
Journal of Crystallization Process and Technology (JCPT) , 2011, DOI: 10.4236/jcpt.2011.12004
Abstract: Pure ammonium diyidrogen phosphate and L-alanine doped ammonium diyidrogen phosphate crystals were grown from aqueous solutions by natural evaporation process. The grown crystals are characterized by Fourier Transform Infrared spectroscopy, Energy Dispersive X-ray, UV-visible spectroscopy and differential thermal analysis. Crystal structure has been studied by powder X-ray diffraction. Pure and doped crystals both possessed tetragonal structure. The optical transparency is found to increase with the increase of doping concentration in the grown crystals and band gap energies of all crystals have been calculated at their cut off frequencies. It is found that the optical band gap increases with doping concentrations. D.C.electrical conductivity of grown crystals along the growth axis was carried out at temperatures ranging from 35-140°C by the conventional two-probe method. The conductivity of the crystals increases with temperature and also increases with the L-alanine concentration. The decomposition temperatures and weight loss have been estimated from the Thermo Gravimetric Analysis and Differential Thermal Analysis and hardness was found from the Vicker’s microhardness measurement.
A Study on Structural, Optical, Electrical and Etching Characteristics of Pure and L-Alanine Doped Potassium Dihydrogen Phosphate Crystals  [PDF]
Ferdousi Akhtar, Jiban Podder
Journal of Crystallization Process and Technology (JCPT) , 2011, DOI: 10.4236/jcpt.2011.13009
Abstract: Pure potassium dihydrogen phosphate (KDP) crystals and KDP doped with L-alanine have been grown by slow evaporation technique at room temperature. Grown crystals have been characterized using powder X-ray diffraction, (XRD), Energy Dispersive X-ray spectroscopy (EDX) and Fourier Transform Infrared spectroscopy (FTIR). The presence of L-alanine into pure KDP crystal was confirmed by FTIR and EDX spectra. Crystal structure has been studied by XRD. Pure KDP and L-alanine doped KDP crystals both possessed tetragonal structure. The transparency is found to increase with the increase of doping concentrations of the grown crystals as observed by UV-Vis spectra. A.C. electrical conductivity of grown crystals along the growth axis was carried out at various temperatures ranging from 35?C - 400?C. Dielectric constant and dielectric losses are measured as a function of temperature and this study reveals the contribution of space charge polarization. Crystal defects and surface morphology are studied by dissolution solvent technique and reveals the step growth mechanism for both pure and doped crystals.
Crystallization and Characterization of Triglycine Sulfate(TGS) Crystal Doped with NiSO4  [PDF]
Farhana Khanum, Jiban Podder
Journal of Crystallization Process and Technology (JCPT) , 2011, DOI: 10.4236/jcpt.2011.13008
Abstract: Nickel sulfate doped triglycine sulfate crystals have been grown by natural evaporation method. The chemical composition of the pure triglycine sulfate crystals and the presence of nickel ion in doped triglycine sulfate crystal were confirmed by Energy Dispersive X-ray analysis. The functional groups of the grown crystals have been identified by the Fourier Transform Infrared spectroscopy. The structural studies on the grown crystals were carried out by X-ray Diffraction analysis. All the grown crystals are found in monoclinic structure and the lattice parameters of pure TGS crystal are a = 9.6010 Å, b = 12.5600 Å and c = 5.4500 Å. The lattice parameters are slightly distorted due to the incorporation of nickel ion into the lattice sites of the TGS crystal.
Effect of Annealing Temperature on Structural, Optical and Electrical Properties of Pure CdS Thin Films Deposited by Spray Pyrolysis Technique  [PDF]
A. Hasnat, J. Podder
Advances in Materials Physics and Chemistry (AMPC) , 2012, DOI: 10.4236/ampc.2012.24034
Abstract:

Effect of annealing temperature on the properties of CdS thin films are carried out in this work. Nanocrystalline cadmium sulphide (CdS) thin films were prepared using spray pyrolysis deposition (SPD) technique and the structural, optical and electrical properties were investigated for different annealing temperature (as deposited, 300, 400 & 500 C). The surface morphology and compositional properties studied by SEM and EDX respectively. The crystal structure of CdS thin film was studied by X-ray diffraction. The crystallite size and lattice constant of SPD CdS thin films were investigated. The optical parameters such as transmittance, absorption coefficient and energy band gap of the films with thermal annealing temperature was investigated by UV/VIS spectrophotometer. The variation of band gap values of CdS thin film samples were found to be in the range of 2.51 to 2.8 eV. Electrical resistivity measurements were carried out in fourprobe Vander Pauw method at different temperature. So CdS films may be a good candidate for suitable application in various optoelectronic devices.

Optical and Electrical Properties of Nanocrystalline SnO2 Thin Films Synthesized by Chemical Bath Deposition Method  [PDF]
Suresh Sagadevan, Jiban Podder
Soft Nanoscience Letters (SNL) , 2015, DOI: 10.4236/snl.2015.54007
Abstract: The chemical bath deposition (CBD) technique was used for the synthesis of the tin oxide (SnO2) thin films. X-ray diffraction (XRD) was employed to find the crystallite size by using Debye Scherrer’s formula. The surface morphology of SnO2 films was analyzed by the scanning electron microscopic (SEM) studies. The FT-IR spectrum exhibits the strong presence of SnO2. The optical properties of the SnO2 thin films were determined using UV-Visible spectrum. The dielectric studies were carried out at different frequencies and at different temperatures for the prepared SnO2 thin films. Further, electronic properties, such as valence electron plasma energy, average energy gap or Penn gap, Fermi energy and electronic polarizability of the SnO2 thin films, were determined. The ac conductivity of the SnO2 thin films increases with increase in temperature and frequency. The activation energy was determined by using dc electrical conductivity measurement. The Hall properties were also calculated.
Mathematical Analysis of Nipah Virus Infections Using Optimal Control Theory  [PDF]
Jakia Sultana, Chandra N. Podder
Journal of Applied Mathematics and Physics (JAMP) , 2016, DOI: 10.4236/jamp.2016.46114
Abstract: The optimal use of intervention strategies to mitigate the spread of Nipah Virus (NiV) using optimal control technique is studied in this paper. First of all we formulate a dynamic model of NiV infections with variable size population and two control strategies where creating awareness and treatment are considered as controls. We intend to find the optimal combination of these two control strategies that will minimize the cost of the two control measures and as a result the number of infectious individuals will decrease. We establish the existence for the optimal controls and Pontryagin’s maximum principle is used to characterize the optimal controls. The numerical simulation suggests that optimal control technique is much more effective to minimize the infected individuals and the corresponding cost of the two controls. It is also monitored that in the case of high contact rate, controls have to work for longer period of time to get the desired result. Numerical simulation reveals that the spread of Nipah virus can be controlled effectively if we apply control strategy at early stage.
Screening of Different Sugarcane Species (Saccharum Officinarum and Saccharum spontaneum) for Red Rot Disease Resistance
R. Baksha,R. Alam,M.M. Kamal,B.P. Podder
Plant Pathology Journal , 2003,
Abstract: Among two different Saccharum species viz; Saccharum officinarum (varieties/ lines Isd 16, Isd 20, Isd 24, Isd 28, BC4 and Saccharum spontaneum (line S 20) were screened against red rot (Colleotrichum falcatum) disease resistance by artificial inoculation following standard plug method. The varieties /lines were graded as various levels of susceptibility and resistance using a standard disease index. Among the varieties/ lines tested Isd 20 and BC4 have shown completely resistant, variety Isd 24, S20 have shown moderately, Isd 16 susceptible and Isd 28 highly susceptible. These varieties/ lines (Isd 20 and BC4) may be utilized as one of the sources of resistance on the breeding programme of sugarcane to red rot disease.
Nature of Gene Action in Barley (Hordeum vulgare L.)
M.M. Rohman,R. Sultana,R. Podder,A.T.M. Tanjimul Islam
Asian Journal of Plant Sciences , 2006,
Abstract: A 6 x 6 diallel cross (excluding reciprocal) of barley (Hordeum vulgare L.) dictated both additive and non-additive components were important but dominance components were more predominant than additive components in controlling the inheritance of all the characters under study. The asymmetric distribution of dominant and recessive alleles at loci was found for all the characters. At least 3 groups of genes were found in controlling the dominance in yield. The highest heritability (89%) in narrow sense was observed in 1000 grain weight. Vr-Wr graph indicated over dominance and genetic diversity among the parents.
Effective Control Strategies on the Transmission Dynamics of a Vector-Borne Disease  [PDF]
Saddam Hossain, Jannatum Nayeem, Chandranath Podder
Open Journal of Modelling and Simulation (OJMSi) , 2015, DOI: 10.4236/ojmsi.2015.33012
Abstract: In this paper, we have rigorously analyzed a model to find the effective control strategies on the transmission dynamics of a vector-borne disease. It is proved that the global dynamics of the disease are completely determined by the basic reproduction number. The numerical simulations (using MatLab and Maple) of the model reveal that the precautionary measures at the aquatic and adult stage decrease the number of new cases of dengue virus. Numerical simulation indicates that if we take the precautionary measures seriously then it would be more effective than even giving the treatment to the infected individuals.
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