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Wyszukujesz frazę "Ghosh, S." wg kryterium: Autor


Tytuł:
Acousto-electric interaction in magnetised piezoelectric semiconductor quantum plasma
Autorzy:
Ghosh, S.
Muley, A.
Powiązania:
https://bibliotekanauki.pl/articles/1058496.pdf
Data publikacji:
2016-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.50.+b
52.35.-g
61.72.uj
77.65.-j
Opis:
Amplification of an acoustic wave is considered in magnetised piezoelectric n-type semiconductor plasma under quantum hydrodynamic regime. The important ingredients of this study are the inclusion of quantum diffraction effect via the Bohm potential, statistical degeneracy pressure, and externally applied magnetostatic field in the momentum balance equation of the charged carriers. A modified dispersion relation is derived for evolution of acoustic wave by employing the linearization technique. Detailed analysis of quantum modified dispersion relation of acoustic wave is presented. For a typical parameter range, relevant to n-InSb at 77 K, it is found that the non-dimensional quantum parameter H reduces the gain while magnetic field enhances the gain of acoustic wave. The crossover from attenuation to amplification occurs at (ϑ₀/ϑₛ)=1 and this crossover point is found to be unaffected by quantum correction and magnetic field. It is also found that the maximum gain point shifts towards lower drift velocity regime due to the presence of magnetic field while quantum parameter H shifts this point towards higher drift velocity. Numerical results on the acoustic gain per radian and acoustic gain per unit length are also illustrated. Our results could be useful in understanding acoustic wave propagation in magnetised piezoelectric semiconductor in quantum regime.
Źródło:
Acta Physica Polonica A; 2016, 130, 6; 1401-1405
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Amplitude Modulation and Demodulation in Strain Dependent Diffusive Semiconductors
Autorzy:
Ghosh, S.
Yadav, N.
Powiązania:
https://bibliotekanauki.pl/articles/2047356.pdf
Data publikacji:
2007-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.35.Mw
72.50.+b
66.30.-h
Opis:
In communication processes, amplitude modulation is very helpful to save power by using a single band transmission. Thus in this paper authors have explored the possibility of amplitude modulation as well as demodulation of an electromagnetic wave in a transversely magnetized electrostrictive semiconductor. The inclusion of carrier diffusion and phenomenological damping coefficient in the nonlinear laser-semiconductor plasma interaction adds a new dimension to the analysis present in this paper. This problem is analyzed in different wave number regimes over a wide range of cyclotron frequencies. It is found that the complete absorption of the waves takes place in all the possible wavelength regimes when the cyclotron frequency (ω$\text{}_{c}$) becomes exactly equal to (ν$\text{}^{2}$+ω$\text{}_{0}^{2}$)$\text{}^{1}\text{}^{/}\text{}^{2}$ in absence of damping parameter. It has also been seen that diffusion of charge carriers modifies amplitude modulation and demodulation processes significantly. The damping parameter plays a very important role in deciding the parameter range and selecting the side band mode that will be modulated by the above-mentioned interaction.
Źródło:
Acta Physica Polonica A; 2007, 112, 1; 29-40
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dispersion and Absorption of Longitudinal Electro-Kinetic Waves in Magnetized Ion-Implanted Semiconductor Plasmas
Autorzy:
Ghosh, S.
Thakur, Preeti
Powiązania:
https://bibliotekanauki.pl/articles/2047263.pdf
Data publikacji:
2007-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.35.Fp
61.72.Ww
82.70.Dd
Opis:
The instability of longitudinal electro-kinetic wave that is propagating across the magnetic field B$\text{}_{0}$ in ion-implanted group-IV semiconductor sample consisting of non-drifting electrons, holes, and negatively charged colloids is investigated. Using hydrodynamic approach, a compact dispersion relation D(ω,k) is derived for the same. The propagation and amplification characteristics of the wave in collision dominated regime are studied numerically in detail for slow and fast modes. Results show that the presence of transverse magnetic field is responsible for the modification of the existing wave spectra of the slow electro-kinetic branch. In case of fast electro-kinetic wave, the presence of magnetic field is found responsible for excitation and amplification of a new mode. It is also found that the magnetic field is responsible for the conversion of two existing aperiodic modes into periodic ones. These novel periodic modes are found to be counter-propagating in nature.
Źródło:
Acta Physica Polonica A; 2007, 111, 2; 247-256
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phonon-plasmon interactions in inhomogeneous semiconductor plasma embedded with nanoparticle cluster
Autorzy:
Ghosh, S.
Dubey, P.
Powiązania:
https://bibliotekanauki.pl/articles/1050820.pdf
Data publikacji:
2018-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.30.+q
72.50.+b
73.22.Lp
Opis:
Phonon-plasmon interaction in inhomogeneous piezosemiconductor embedded with a nanoparticle cluster is examined using hydrodynamic model of plasma and macroscopic model of piezoelectric media. Present work dealt with the extensive investigation of acoustic wave amplification characteristics. The effects of density gradient δ and non-dimensional parameter l related to nanoparticle cluster on acoustic gain have been studied with varying medium electron density n_{0e}, wave frequency ω and velocity ratio ϑ_{0}/ϑ_{s}. The results so obtained, infer that the varying inhomogeneity and presence of nanoparticle cluster within the semiconductor plasma medium play decisive role in depicting the gain characteristics of acoustic wave.
Źródło:
Acta Physica Polonica A; 2018, 133, 5; 1287-1293
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strongly Correlated Electron Behaviour in $CeT_2Al_8$ (T~=~Fe,~Co)
Autorzy:
Ghosh, S.
Strydom, A.
Powiązania:
https://bibliotekanauki.pl/articles/1427072.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Cx
71.27.+a
75.30.Mb
75.20.Hr
Opis:
We report on studies of physical properties of the two compounds $CeFe_2Al_8$ and $CeCo_2Al_8$ in which we have found varying degrees of electronic correlational phenomena. No magnetic ordering was detected down to 0.4 K in either of the two compounds. At elevated temperatures an incoherent Kondo interaction between the Ce 4f-electron and the conduction electrons is prevalent in both compounds. $CeCo_2Al_8$ exhibits a stable 4f-electron magnetic moment, but in $CeFe_2Al_8$ an intermediate-valent state prevails near room temperature that eventually transforms into a Fermi-liquid ground state. The low-temperature specific heat of $CeCo_2Al_8$ shows typical strongly correlated electron behaviour and a - logT upturn in its electronic specific heat below about 10 K.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1082-1084
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Density Gradient on the Acousto-Electric Wave Instability in Ion-Implanted Semiconductor Plasmas
Autorzy:
Ghosh, S.
Khare, Pragati
Powiązania:
https://bibliotekanauki.pl/articles/2044639.pdf
Data publikacji:
2006-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Vv
72.30.+q
82.70.Dd
Opis:
Using hydrodynamic model of inhomogeneous plasma, an analytical investigation of excitation of acousto-electric mode was made in n-type piezoelectric ion-implanted semiconductor plasma. By employing the multi-fluid balance equations along with the elastic and Maxwell equations, a compact dispersion relation for the cases in which colloidal grains are either stationary (ϑ$\text{}_{0d}$=0) or streaming (ϑ$\text{}_{0d}$≢0$) is derived. We find that the choice of homogeneous medium is favorable in achieving higher acoustic gain per radian and the results of the investigation should be useful in understanding the characteristics of longitudinal acousto-electric wave in ion-implanted piezoelectric semiconductor whose main constituents are electrons and negatively charged colloidal particles.
Źródło:
Acta Physica Polonica A; 2006, 109, 2; 187-197
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bioleaching of nickel by Aspergillus humicola SKP102 isolated from Indian lateritic overburden
Autorzy:
Ghosh, S.
Paul, A. K.
Powiązania:
https://bibliotekanauki.pl/articles/92057.pdf
Data publikacji:
2016
Wydawca:
Główny Instytut Górnictwa
Tematy:
Fungal bioleaching
Aspergillus humicola
chromite mining overburden
nickel leaching
bioługowanie
wymywanie niklu
Opis:
The lateritic deposits spread over the Eastern Ghats of Sukinda Valley, Odisha, India, produce a huge amount of overburden annually as a byproduct of chromite mining. This chromite mining overburden contains nickel, the only source of the metal in the country. During this study Aspergillus humicola SKP102, an indigenous fungus isolated from the mining overburden was employed for the leaching of nickel. About 53.89% of the nickel could be leached by the fungus when grown in batch mode using a Czapek dox medium containing 2% (w/v) of the mining overburden. The parameters affecting bioleaching were optimized in order to grow the fungus and leach the metal. Of the different options of cheap carbon sources, straw infusion and molasses emerged as viable options for the growth of the fungus and the leaching of nickel. Two-step and indirect techniques were also used for this purpose, and they resulted in 53.09% and 65.04% Ni leaching respectively. Adding diluted sulfuric acid to the leaching medium resulted in 97.05% nickel recovery from the overburden pulp. A. humicola SKP102 could be a potential tool for leaching nickel from the mining overburden.
Źródło:
Journal of Sustainable Mining; 2016, 15, 3; 108-114
2300-1364
2300-3960
Pojawia się w:
Journal of Sustainable Mining
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trend analysis of climate change in Chittagong Station in Bangladesh
Autorzy:
Roy, M.
Biswas, B.
Ghosh, S.
Powiązania:
https://bibliotekanauki.pl/articles/11430.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:
The amount of rainfall received over an area is an important factor in assessing availability of water to meet various demands for agriculture, industry, irrigation, generation of hydroelectricity and other human activities. Over the study period of recent 30 years, trend values of monsoon average rainfall in Chittagong have increased. This paper has measured the correlation coefficients between rainfall and time for Chittagong, where correlation coefficient for Chittagong is positive. In order to check the strength of linear relationship between rainfall and time, P-value has been measured. Due to various factors of Chittagong region of Bangladesh, there is a growing need to study the rainfall, temperature and humidity pattern. This study was checked annual average rainfall of 30 years, temperature of 60 years and humidity of 28 years for this region. It is hoped that this research may be of help to the concerned organizations and experts working on increasing climate variation in Chittagong.
Źródło:
International Letters of Natural Sciences; 2015, 47
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parametric Amplification in Magnetized Nondegenerate Semiconducting Plasmas
Autorzy:
Jat, K. L.
Neogi, A.
Ghosh, S.
Powiązania:
https://bibliotekanauki.pl/articles/1887743.pdf
Data publikacji:
1991-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.Ky
72.20.Ht
73.50.Rb
78.20.Hp
Opis:
Using the straightforward coupled-mode theory, the parametric amplification is analytically investigated in magnetized piezoelectric as well as non-piezoelectric semiconductors. The origin of nonlinear interaction is taken to be in the second-order optical susceptibility χ$\text{}^{(2)}$ arising from the nonlinear induced current density. The threshold value of the pump electric field E$\text{}_{0th}$ is obtained for crystals. E$\text{}_{0th}$ is found to decrease with the rise in magnetic field and fall with the rise in scattering angle. Parametric gain constants are obtained for different situations of practical interest, i.e. (i) for piezoelectric coupling only g$\text{}_{p}$, (ii) for deformation potential coupling only g$\text{}_{d}$, (iii) for both the couplings g$\text{}_{b}$. Numerical investigations reveal that the magnetic field increases the gain. Maximum gains are obtained for backward scattered mode. g$\text{}_{d}$ is always found to be less than g$\text{}_{p}$ and g$\text{}_{b}$. It is also found that g$\text{}_{p}$ and g$\text{}_{b}$ both are identical up to k ≈ x 10$\text{}^{7}$m$\text{}^{-1}$ and for k ≥ 3 x 10$\text{}^{7}$m$\text{}^{-1}$, g$\text{}_{b}$ exceeds g$\text{}_{p}$.
Źródło:
Acta Physica Polonica A; 1991, 79, 6; 829-841
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Thermomechanical Controlled Processing and Quenching & Tempering on the Structure and Properties of Bainite-Martensite Steels
Autorzy:
Mandal, G.
Ghosh, S. K.
Chatterjee, S.
Powiązania:
https://bibliotekanauki.pl/articles/353508.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steels
TMCP
heat treatment
microstructure
mechanical properties
Opis:
In the present time, advanced high strength steel (AHSS) has secured a dominant place in the automobile sector due to its high strength and good toughness along with the reduced weight of car body which results in increased fuel efficiency, controlled emission of greenhouse gases and increased passengers’ safety. In the present study, four new advanced high strength steels (AHSS) have been developed using three different processing routes, i.e., thermomechanical controlled processing (TMCP), quenching treatment (QT ), and quenching & tempering (Q&T) processes, respectively. The current steels have achieved a better combination of the high level of strength with reasonable ductility in case of TMCP as compared to the other processing conditions. The achievable ultrahigh strength is primarily attributed to mixed microstructure comprising lower bainite and lath martensite as well as grain refinement and precipitation hardening.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 2; 861-868
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model-building adaptive critics for semi-Markov control
Autorzy:
Gosavi, A.
Murray, S.
Hu, J.
Ghosh, S.
Powiązania:
https://bibliotekanauki.pl/articles/91878.pdf
Data publikacji:
2012
Wydawca:
Społeczna Akademia Nauk w Łodzi. Polskie Towarzystwo Sieci Neuronowych
Tematy:
adaptive critics
learning algorithm
semi-Markov process
decision process
Opis:
Adaptive (or actor) critics are a class of reinforcement learning algorithms. Generally, in adaptive critics, one starts with randomized policies and gradually updates the probability of selecting actions until a deterministic policy is obtained. Classically, these algorithms have been studied for Markov decision processes under model-free updates. Algorithms that build the model are often more stable and require less training in comparison to their model-free counterparts. We propose a new model-building adaptive critic, which builds the model during the learning, for a discounted-reward semi-Markov decision process under some assumptions on the structure of the process. We illustrate the use of our algorithm with numerical results on a system with 10 states and a real-world case-study from management science.
Źródło:
Journal of Artificial Intelligence and Soft Computing Research; 2012, 2, 1; 43-58
2083-2567
2449-6499
Pojawia się w:
Journal of Artificial Intelligence and Soft Computing Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Navigation of autonomous mobile robot using different activation functions of wavelet neural network
Autorzy:
Panigrahi, P. K.
Ghosh, S.
Parhi, D. R.
Powiązania:
https://bibliotekanauki.pl/articles/229613.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
autonomous mobile robot
activation functions
obstacle avoidance
path planning
wavelet neural network
Opis:
An autonomous mobile robot is a robot which can move and act autonomously without the help of human assistance. Navigation problem of mobile robot in unknown environment is an interesting research area. This is a problem of deducing a path for the robot from its initial position to a given goal position without collision with the obstacles. Different methods such as fuzzy logic, neural networks etc. are used to find collision free path for mobile robot. This paper examines behavior of path planning of mobile robot using three activation functions of wavelet neural network i.e. Mexican Hat, Gaussian and Morlet wavelet functions by MATLAB. The simulation result shows that WNN has faster learning speed with respect to traditional artificial neural network.
Źródło:
Archives of Control Sciences; 2015, 25, 1; 21-34
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design, molecular docking, drug-likeness, and molecular dynamics studies of 1,2,4-trioxane derivatives as novel Plasmodium falciparum falcipain-2 (FP-2) inhibitors
Autorzy:
Ghosh, S.
Chetia, D.
Gogoi, N.
Rudrapal, M.
Powiązania:
https://bibliotekanauki.pl/articles/2096418.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
1
2
4-trioxane
Plasmodium falciparum
drug resistance
molecular docking
molecular dynamics
falcipain 2 inhibitors
Opis:
Despite significant progress made in drug discovery and development over the past few decades, malaria remains a life-threatening infectious disease across the globe. Because of the widespread emergence of drug-resistant strains of Plasmodium falciparum, the clinical utility of existing drug therapies including Artemisinin-based Combination Therapies (ACTs) in the treatment of malaria has been increasingly limited. It has become a serious health concern which, therefore, necessitates the development of novel drug molecules and/or alternative therapies to combat, particularly resistant P. falciparum. The objective of the present study was to develop 1,2,4-trioxane derivatives as novel antimalarial agents that would be effective against resistant P. falciparum. In our study, 15 new trioxane derivatives were designed by molecular modification of the 1,2,4-trioxane scaffold as possible antimalarial agents. Molecular modeling studies of trioxane derivatives were performed based on the CADD approach using Biovia Discovery Studio (DS) 2018 software. The protein-ligand docking study was performed against P. falciparum falcipain 2 (FP-2) using the simulation-based docking protocol LibDock by the flexible docking method. The assessment of drug-likeness, ADMET properties, and toxicity was also performed. Furthermore, the compounds CC3 and CC7, which showed the best binding affinity against the target P. falciparum FP-2, were investigated by molecular dynamics (MD) simulation studies followed by the calculation of MM-PBSA binding free energy of protein-ligand complexes using DS 2020. Results of the docking study showed that among the 15 compounds, three trioxane derivatives were found to possess promising binding affinity with LibDock scores ranging from 117.16 to 116.90. Drug-likeness, ADMET, and toxicity properties were found to be satisfactory for all the compounds. Among the 15 compounds, two compounds, namely CC3 and CC7, showed the highest binding affinity against FP-2 with LibDock score of 117.166 and 117.200, respectively. The Libdock score of the co-crystal inhibitor was 114.474. MD studies along with MM-PBSA calculations of binding energies further confirmed the antimalarial potential of the compounds CC3 and CC7, with the formation of well-defined and stable receptor-ligand interactions against the P. falciparum FP-2 enzyme. Additionally, the selectivity of trioxane hits identified as potential inhibitors of P. falciparum cysteine protease FP-2 was determined on human cysteine proteases such as cathepsins (Cat K and Cat L), which are host homologous. Finally, it was concluded that the newly designed 1,2,4-trioxane derivatives can be further studied for in vitro and in vivo antimalarial activities for their possible development as potent antimalarial agents effective against resistant P. falciparum
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2021, 102, 3; 257-275
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparative Assessment of the Impact of Different Occupations on Workers’ Static Musculoskeletal Fitness
Autorzy:
Chandra, A. M.
Ghosh, S.
Iqbal, R.
Sadhu, N.
Powiązania:
https://bibliotekanauki.pl/articles/90250.pdf
Data publikacji:
2007
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
occupations
repetitive movements
static muscular forces
musculoskeletal disorders
dynamometry
Opis:
An ergonomic assessment of the involvement of static muscular forces like back strength, grip strength and pinch strength in different occupations was made. A study was conducted on 45 normal adult males (15 subjects per group) which included video display terminal (VDT) operators, industrial workers and safety inspectors. Their maximum back strength, handgrip strength and pinch strength were measured with dynamometers. The observed values of back strength were significantly lower in VDT operators while significantly higher in safety inspectors and moderate in industrial workers. The values of grip strength and pinch strength of all sample groups were more or less similar. The findings clearly indicate that static muscular strength varies significantly in different occupations. Heavy static muscular load might lead to an accumulation of metabolic waste and toxins on the back resulting in lower back strength in VDT operators and industrial workers.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2007, 13, 3; 271-278
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seeking the best practices of assessment in maritime simulator training
Autorzy:
Tusher, H. M.
Nazir, S.
Ghosh, S.
Rusli, R.
Powiązania:
https://bibliotekanauki.pl/articles/24201462.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
maritime education and training
human factor
maritime simulator training
assessments in simulated environments
Performance Assessment
assessment model
STCW
literature review
Opis:
Simulator-based training has become an integral part of Maritime education, and its effectiveness hinges on the use of appropriate assessment protocols. Despite the existence of several subjective and objective assessment techniques, instructors face difficulties in selecting and implementing the best practices that fit different learning contexts. The contextualized utility of the available assessment techniques further complicates the contexts. This study adopts a systematic literature review approach to comprehensively analyse available assessment techniques employed in maritime simulator training and to elicit their relationship with the desired learning outcomes. The study also presents a nuanced understanding of the advantages and limitations of the identified assessment techniques. Further, the state-of-the-art of assessment methods is discussed along with a few proposals for the future considering both research and practical implications. The findings of this study are expected to provide valuable guidance to maritime instructors in selecting and implementing appropriate assessment techniques that align with desired learning outcomes in simulator training.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2023, 17, 1; 105--114
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł

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