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Wyszukujesz frazę "Das, S K." wg kryterium: Autor


Tytuł:
A Green Function Estimation of Correction to Vegards Law for isovalent Substitutional Defects in Alkali Halide Crystals
Autorzy:
Datta Roy (Paul), S.
Das, S. K.
Powiązania:
https://bibliotekanauki.pl/articles/2013286.pdf
Data publikacji:
2000-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Bb
61.82.Bg
Opis:
A Green function method is developed for estimation of lattice parameter r(χ) of an AX-BX solid solution over entire composition range (χ=0 to 1). The r(χ) obtained in the present method is different from the value r$\text{}_{V}$(χ) suggested by Vegard's law. We estimated the deviation from Vegard's law, r(χ)-r$\text{}_{V}$(χ), over entire composition range for isovalent substitutional defect in alkali halide crystals. When compared to X-ray diffraction measurements, we find that the deviation is in correct direction, variation of r(χ) with χ is consistent with experiment and the overall agreement is fairly good considering the accuracy of the experiment.
Źródło:
Acta Physica Polonica A; 2000, 97, 4; 671-679
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heuristic Procedure for the Assembly Line Balancing Problem With Postural Load Smoothness
Autorzy:
Jaturanonda, C.
Nanthavanij, S.
Das, S. K.
Powiązania:
https://bibliotekanauki.pl/articles/90459.pdf
Data publikacji:
2013
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
assembly line balancing
postural load smoothness
upper extremities disorders
RULA
linia montażowa
obciążenie
kończyny górne
Opis:
This paper presents a heuristic procedure for assigning assembly tasks to workstations where both productivity and ergonomics issues are considered concurrently. The procedure uses Kilbridge and Wester’s algorithm to obtain an initial task–workstation assignment solution which minimizes the balance delay of an assembly line. A task reassignment algorithm was applied to improve the initial solution by exchanging assembly tasks, which smooth postural load among workers, between workstations. A composite index of variation was used to measure the effectiveness of the task–workstation assignment solution. On the basis of clothes assembling, it was found that the task–workstation assignment solution with a minimum composite index of variation can be obtained with relatively equal weights in balance delay and postural load.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2013, 19, 4; 531-541
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculation of Lattice Relaxation in Some Substitutional Alloys Using a Green Function
Autorzy:
Das, S. K.
Datta Roy (Paul), S.
Powiązania:
https://bibliotekanauki.pl/articles/1995663.pdf
Data publikacji:
1999-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Bb
61.82.Bg
Opis:
In this paper we calculate nearest neighbour relaxation in some dilute substitutional alloys using a lattice static Green function and the Morse potential function. Distant neighbour relaxation is calculated by invoking a continuum approximation. The potential parameters for the unlike interactions are calculated using simple interpolation formulae. Using the above relaxation, we calculate volume changes in the above alloys. It is observed that the simple model predicts values which are in reasonably good agreement with the experimental values in all cases. The calculated values are also compared with those obtained from the Vegard law. For Au-Ag alloy, our model reproduces both the correct sign and the magnitude of the volume change, whereas the Vegard law cannot even give the sign of the volume change. This shows the inherent strength of the present model.
Źródło:
Acta Physica Polonica A; 1999, 95, 3; 359-366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Properties of Carbon Nanotube (CNT) Reinforced Polyvinyl Alcohol (PVA) Composites
Autorzy:
Hasan, M.
Das, S. K.
Islam, J. M. M.
Gafur, Md. A.
Hoque, E
Khan, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/411675.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
CNT
PVA
composite
Thermal properties
Gum acacia
Opis:
Homogeneous Polyvinyl alcohol (PVA)/Carbon nanotube (CNT) composite has been prepared by solution casting method using gum acacia as a surfactant. CNT content in the composite was varied from 5-10 % by weight. The thermal properties of PVA/CNT composites were investigated by Thermo Gravimetric/Differential Thermal Analyzer (TG/DTA) and Thermo Mechanical Analyzer (TMA). TG/DTA results showed that higher thermal stability in higher percentage of CNT in the composites. The 10 % CNT containing PVA composite exhibit highest onset of melting, glass transition point and offset of melting temperature and the recoded values are 330.4K, 379K and 421.3K respectively. All of the result indicates that the developed PVA/CNT composite might be promising for use in solar cell application.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 12; 59-66
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of Electrically Conductive Nanocrystalline Thin Film for Optoelectronic Applications
Autorzy:
Das, S K.
Islam, J. M. M.
Hasan, M.
Kabir, H.
Gafur, Md. A.
Hoque, E.
Khan, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/412543.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Conductive thin film
Composite
TiO2
Solar cell
Optoelectronics
Sodium alginate
Opis:
Sodium alginate (TiO2) sand composites were prepared by solution casting. Purified sand was added in the composite films to increase electrical conductivity. Electrical properties such as conductivity, capacitance, dielectric constant, and loss tangent of the composites were investigated. The current voltage characteristics for all the composites showed ohmic behavior. All the electrical properties have been found to improve with the incorporation of sand (SiO2) but 6 % sand containing composite exhibits the best electrical properties. The mechanical properties tensile strength (TS), elongation at break (Eb) and Young modulus for 6 % sand containing composite film are found to be 4.445 MPa, 9.76 %, and 72.8 MPa respectively. The experimental results reveal that the blended films exhibit higher stability and improved mechanical properties of both tensile strength and elongation at break in dry state. Water absorption properties of the composites are found to decrease with the increase of sand content. Lowest water uptake properties and highest stability were demonstrated by 6 % sand containing sample. Electrically conductive composite films have useful applications for solar cells and optoelectronics. Thus, this study is very much expected to aid in the design and selection of proper composite for the potential application of solar cell and optoelectronics.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 10, 1; 90-101
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First report of twig blight of ban tulsi (Croton bonplandianus Bail.) caused by Choanephora cucurbitarum (Berk.and Ravenel) Thaxt. in India
Autorzy:
Das, S.
Dutta, S.
Ray, S.K.
Powiązania:
https://bibliotekanauki.pl/articles/65731.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
twig blight
ban tulsi
Croton bonplandianus
Euphorbiaceae
herb
perennial plant
folk medicine
Choanephora cucurbitarum
plant pathogen
sporangium
India
Opis:
In August 2015, twig blight disease of ban tulsi (Croton bonplandianus Bail.) caused by Choanephora cucurbitarum (Berk. & Ravenel) Thaxt. was observed for the first time, in the Gangetic alluvial region of West Bengal, India. A severe disease incidence (40–50%) showed twig blight symptoms starting with shoot apical meristem (SAM), leaf, and blossom blight symptoms. Typical symptoms were characterized by over-projecting black pin head like emerging sporangiola which formed mycelial cushion on the infected surface. The present report describes the identification of the causal pathogen as C. cucurbitarum based on its morphology and the internal transcribed spacer of its ribosomal DNA (rDNA – ITS) sequences with 100% identity of NCBI-GenBank published Choanephora database. Optimum temperatures, 28–30°C, coupled with high relative humidity (80–90%) during the monsoon season enhances the disease’s progress. To the best of our knowledge this is the first report of twig blight of C. bonplandianus, caused by C. cucurbitarum, in India as well as globally.
Źródło:
Journal of Plant Protection Research; 2017, 57, 4
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature and Frequency Dependence Electrical Properties of $Zn_{1-x}Ca_{x}O$ Nanoceramic
Autorzy:
Das, T.
Das, B.
Parashar, K.
Parashar, S.
Powiązania:
https://bibliotekanauki.pl/articles/1398349.pdf
Data publikacji:
2016-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.cP
68.37.xy
84.37.+q
72.80.Lc
77.22.Ch
Opis:
This work reports the temperature and frequency dependence electrical properties of Ca doped ZnO ($Zn_{1-x}Ca_{x}O$, x=0.01) nanoceramic synthesized by solid state reaction method. The X-ray spectra show that the synthesized powder has hexagonal wurtzite structure with space group P6₃mc. The average crystallite size decreases with Ca doping. The increase in oxygen positional parameter (u) indicates lattice distortion in the crystal structure. Doping with Ca caused a slight shift in the (101) plane peak towards lower diffraction angle. The formation of pores in field emission scanning electron microscopy micrograph may be due to the defect created by Ca substitution. The electrical property was investigated by impedance spectroscopy in the temperature range 300-500°C. The synthesized sample shows temperature dependence relaxation phenomena and negative temperature coefficient of resistance effects. Electrical conductivity ($σ_{ac}$) increases with increase in temperature as well as with frequency due to the drift mobility of electrons and hole by hopping conduction. Dielectric constant was found to decrease with increase in frequency and temperature. This decreases drastically in the magnitude of approximately < 10 times than the corresponding undoped one.
Źródło:
Acta Physica Polonica A; 2016, 130, 6; 1358-1362
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On \(RS_k\) integrals
Autorzy:
Das, A. S.
Lahiri, В. K.
Powiązania:
https://bibliotekanauki.pl/articles/745404.pdf
Data publikacji:
1980
Wydawca:
Polskie Towarzystwo Matematyczne
Opis:
The article contains no abstract
Źródło:
Commentationes Mathematicae; 1980, 22, 1
0373-8299
Pojawia się w:
Commentationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biomonitoring tool: morphological anomalies in Zygnema sp. of Ganga River Bank
Autorzy:
Das, K.
Gupta, K.
Swarnakar, S.
Talapatra, S.N.
Powiązania:
https://bibliotekanauki.pl/articles/11639.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:
The present study aims to detect morphological abnormalities in Zygnema sp. because this test species have high adaptive capacity in unfavourable environmental stress. This alga is inhabited at the suburban bank of river Ganga, West Bengal, India. The study was done at experimental sites, downstream at Khardah near sewage water mixing area was compared with upstream control site Kalyani as no sewage water discharge. External and internal abnormal morphology such as undulating or wavy and extra outgrowth on cell wall, sometimes bending inwardly and outwardly as external deformities while internal anomalies such as pigment loss, nucleus was in circular, rectangular, oval and amoeboid shapes, also vacuolated and trilobed, broom like chloroplasts and central part of the thallas dried in between two segments. It was observed that this test species was surviving and well adapted with above mentioned deformities. The present preliminary study with Zygnema sp. can be utilized for in situ and ex situ indicator species for riverine biomonitoring. Further research may be relevant to know both tolerant and sensitive algae species inhabited at the river Ganga bank alongwith biochemical and genetic parameters. The present work is suggesting that other inhabiting algae and this adaptive test species can be used for bioremediation of pollutants.
Źródło:
International Letters of Natural Sciences; 2015, 47
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Slip effects on squeezing flow of nanofluid between two parallel disks
Autorzy:
Das, K.
Jana, S.
Acharya, N.
Powiązania:
https://bibliotekanauki.pl/articles/264490.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
pole magnetyczne
tarcie
poślizg
nanofluid
slip effect
squeezing flow
magnetic field
Opis:
In this study, the influence of temperature and wall slip conditions on the unsteady flow of a viscous, incompressible and electrically conducting nanofluid squeezed between two parallel disks in the presence of an applied magnetic field is investigated numerically. Using the similarity transformation, the governing coupled partial differential equations are transformed into similarity non-linear ordinary differential equations which are solved numerically using the Nachtsheim and Swigert shooting iteration technique together with the sixth order Runge-Kutta integration scheme. The effects of various emerging parameters on the flow characteristics are determined and discussed in detail. To check the reliability of the method, the numerical results for the skin friction coefficient and Nusselt number in the absence of slip conditions are compared with the results reported by the predecessors and an excellent agreement is observed between the two sets of results.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 1; 5-20
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of mixed traffic for mobile cellular network
Autorzy:
Islam, I.
Das, J. K.
Hossain, S.
Powiązania:
https://bibliotekanauki.pl/articles/307662.pdf
Data publikacji:
2007
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
quality of service
Markovian chain
time and call congestion
probability states and voice data integrated network
Opis:
The most convenient way of presenting one- or two-dimensional offered traffic in a network by Markovian chain to evaluate quality of service (QoS). Pictorial presentation of chain becomes very complicated for three dimensional traffic case, required for voice data integrated service/mixed traffic of mobile cellular network; hence application of cut or node equations become a cumbersome job. This paper proposes a model of three-dimensional traffic in a network for both unlimited and limited user case. Here direct analytical method is introduced instead of Markovian chain to achieve traffic parameters.
Źródło:
Journal of Telecommunications and Information Technology; 2007, 1; 83-89
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of voice data integrated traffic in 3G mobile cellular network
Autorzy:
Islam, I.
Das, J. K.
Hossain, S.
Powiązania:
https://bibliotekanauki.pl/articles/308765.pdf
Data publikacji:
2007
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
3G mobile
voice data integrated service
micro cell
macro cell
satellite cell
Markovian chain and thinning scheme
Opis:
The most important feature of 3G mobile cellular network is introduction of voice data integrated service under multilayered cell environment to support overflow traffic of lower layered cells by upper ones. This paper deals with traffic model of three layered cells, i.e., micro cell, macro cell and satellite cell. Here a new call admission control is introduced for three layered cell of 3G mobile cellular network. State transition chain is designed for theoretical analysis of above mentioned traffic. Blocking probability of data call, new voice call and handover failure of voice call, probability of utilization of micro cell channel, macro cell channel and satellite cell channel are analyzed against different traffic parameters and yield logical results.
Źródło:
Journal of Telecommunications and Information Technology; 2007, 2; 103-108
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variation of Electrical Resistivity with High Pressure in Ge-Te-Sn Glasses: A Composition Dependent Study
Autorzy:
Prasad, K.
Das, Chandasree
Rukmani, K.
Asokan, S.
Powiązania:
https://bibliotekanauki.pl/articles/1400510.pdf
Data publikacji:
2015-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ng
Opis:
The variation of normalized electrical resistivity in the system of glasses $Ge_{15}Te_{85-x}Sn_{x}$ with (1 ≤ x ≤ 5) has been studied as a function of high pressure for pressures up to 9.5 GPa. It is found that with the increase in pressure, the resistivity decreases initially and shows an abrupt fall at a particular pressure, indicating the phase transition from semiconductor to near metallic at these pressures, which lie in the range 1.5-2.5 GPa, and then continues being metallic up to 9.5 GPa. This transition pressure is seen to decrease with the increase in the percentage content of tin due to increasing metallicity of tin. The semiconductor to near metallic transition is exactly reversible and may have its origin in a reduction of the band gap due to high pressure.
Źródło:
Acta Physica Polonica A; 2015, 127, 6; 1666-1671
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of antimutagenic avenue and wild plant diversity on roadside near Nature Park, Kolkata, India
Autorzy:
Das, S.
Benerjee, K.
Nandy, A.
Nath Talapatra, S.
Powiązania:
https://bibliotekanauki.pl/articles/11170.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:
The study of diversity of plants in an urban area is a suitable measure of the terrestrial ecosystem. The study of avenue and wild plants diversity is an important research work, which provides knowledge about naturally occurring chemicals in plants, to protect against mutation, cancer and other diseases. These are commonly called as phytochemicals and the natural chemical ingredients are potent to use in antimutagenicity. The present study aims to understand the occurrence and population nos. of different avenue and wild plants planted or natural on roadside near Nature Park, Kolkata, India. The results clearly indicate that a total population of these plant species are having 282 nos. in the study area. Various literatures clearly revealed that these plants and/or their parts have potent antimutagenic properties by the presence of several phytochemicals. In conclusion, present preliminary research emphasizes an occurrence of antimutagenic avenue and wild plants on roadsides, containing natural chemical ingredients. Previous research works confirmed that toxins or mutagens or carcinogens may cause mutation that leads to cancer. The present study is a preliminary assessment of antimutagenic avenue and wild plant species diversity that have not yet been studied in that particular geographical area. The present study also suggested that avenue and wild plants are suitable for antimutagenic potential along with aesthetical view of human as well as ecosystem support. Therefore, biodiversity study, phytochemicals estimation and conservation of these particular plant species and/or different antimutagenic species in other local area viz. roadsides, parks, forests etc. might be relevant because the plant species can be used for herbal medicine in human healthcare as well as to prevent mutation and cancer.
Źródło:
International Letters of Natural Sciences; 2015, 02
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kinetics and mechanism of electron transfer to pyridinium chlorochromate (VI) from sulfur containing amino acid, L-cysteine in aqueous and micellar media
Autorzy:
Senapati, S.
Das, S.
Mohanty, P.
Patnaik, A.K.
Powiązania:
https://bibliotekanauki.pl/articles/779166.pdf
Data publikacji:
2011
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
kinetyka
przeniesienie elektronu
chlorochromian pirydyny
cysteina
kinetics mechanism
electron transfer
pyridinium chlorochromate
cysteine
micellar media
Opis:
The electron transfer reaction of L-cysteine (RSH) with pyridinium chlorochromate (PCC) has been studied spectrophotometrically over the range 2.0 ≤ 10^3 [RSH] ≤ 6.0; 0.01 ≤ [H+] ≤ 0.2; 298 ≤ T ≤ 318 K and I = 0.3 mol dm-3 (NaClO4). The electron transfer reaction has also been carried out in the presence of anionic, cationic and neutral micelle. The reaction in acid medium is strongly catalyzed by changing [SDS]T (sodium dodecyl sulfate) up to 3 × 10-2 mol dm-3, beyond this concentration of SDS, the rate is retarded. The cationic and neutral micelle has a small effect on the rate. ΔH≠ (kJ mol-1) and ΔS≠ (JK-1 mol-1) values for the k1 and k2 paths are 30.20 ± 0.25, -159.65 ± 0.83 and 29.60 ± 0.62, -127.09 ± 2.17, respectively. The negative activation entropy is indicative of the ordered transition state for the electron transfer reaction. Formation of 2-amino-3-(2-amino-2-carboxy-ethyl) disulfanyl-propanoic acid as product is strongly supported by IR spectra.
Źródło:
Polish Journal of Chemical Technology; 2011, 13, 2; 6-10
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł

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