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


Tytuł:
Trend of arsenic pollution and subsequent bioaccumulation in Oryza sativa and Corchorus capsularis in Bengal Delta
Autorzy:
Bhattacharya, S.
Guha, G.
Gupta, K.
Chattopadhyay, D.
Mukhopadhyay, A.
Ghosh, U.C.
Powiązania:
https://bibliotekanauki.pl/articles/10831.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
trend
arsenic pollution
bioaccumulation
rice
Oryza sativa
jute
Corchorus capsularis
Bengal Delta zob.Ganges Delta
Ganges River
Ganges Delta
Opis:
Oryza sativa Linn. (rice) and Corchorus capsularis Linn. (jute) are the two major crops of the Bengal basin. Both rice and jute are generally grown in submerged flooded conditions, where arsenic bioavailability is high in soil. The consumers of the edible parts from both plants therefore face an inevitable source of exposure to arsenic, with consequent accumulation and toxicity. The objective of the study was to observe the in-vivo temporal variation of arsenic bioaccumulation in the different parts of O. sativa and C. capsularis. Rice plant specimens (Aman rice, Ratna variety) of different age groups (1, 2 and 3 months old) were analyzed in HG-AAS for absorbed arsenic content in different parts. The accumulation of arsenic remained significantly high in the initial phase of growth, but decreased with time. Amount of arsenic bioaccumulation followed the decreasing order: root > basal stem > median stem > apical stem > leaves > grains in all the three age groups of the rice plant samples. C. capsularis followed a trend of arsenic bioaccumulation similar to O. sativa. O. sativa had more accumulation potential than C. capsularis, but C. capsularis showed much higher efficiency of arsenic translocation in the above ground parts. This is the first ever report of time-dependent decrease in arsenic bioaccumulation in O. sativa and C. capsularis. The contamination level can reach the grain part in significant amount and can cause health hazards in more severely arsenic affected areas. Intensive investigation on a complete food chain is urgently needed in the arsenic contaminated zones for further risk assessments.
Źródło:
International Letters of Natural Sciences; 2014, 16
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Early Pliocene calcareous and siliceous microfossils of the Sawai Bay Formation, Car Nicobar Island, northern Indian Ocean
Autorzy:
Chakraborty, Arindam
Ghosh, Amit K.
Mccartney, Kevin
Saxena, Stuti
Dey, Rikee
Roy, Lopamudra
Powiązania:
https://bibliotekanauki.pl/articles/1835597.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Zanclean
calcareous nannofossils
radiolarians
diatoms
silicoflagellates
sponge spicules
Andaman islands
Nicobar islands
India
nanoplankton wapienny
radiolarie
okrzemki
wyspy Andaman
wyspy Nicobar
Indie
Opis:
The present contribution provides a study of calcareous nannofossils and siliceous microfossils from the Sawai Bay Formation on Car Nicobar Island, northern Indian Ocean. Two stratigraphically short sediment intervals near Sawai Bay have been examined. Qualitative and quantitative microfossil analyses show the Sawai Bay ‘A’ Section to be devoid of siliceous microfossils, while 24 well-preserved calcareous nannofossil taxa are identified. The Sawai Bay ‘B’ Section yields 18 calcareous nannofossil, 33 radiolarian and 25 diatom taxa. The calcareous nannofossil index taxa (Ceratolithus armatus Müller, 1974a and C. cristatus Kamptner, 1950) indicate both sections to be from zones NN12 (CN10b) and NN13 (CN10c) of early Pliocene (Zanclean) age. The radiolarian taxa, i.e., Didymocyrtis avita Riedel, 1953, Euchitonia spp., Siphocampe lineata (Ehrenberg) Nigrini, 1977, Stichocorys peregrina Riedel, 1953, Semantis spp. and Stylochlamydium sp. are common in the Sawai Bay ‘B’ Section, which is assigned to Zone RN9. Most of the diatom taxa are represented by rep-resentatives of the genera Actinocyclus Ehrenberg, 1837, Azpeitia Peragallo in Tèmpere and Peragallo, 1912, Coscinodiscus Ehrenberg, 1839a, Grammatophora Ehrenberg, 1841 and Triceratium Ehrenberg, 1839b, with the benthic diatom species Triceratium favus Ehrenberg, 1839b being predominant (~35% of the total diatom count). Siliceous microfossils are also represented by silicoflagellates dominated by Dictyocha spp. and sponge spicules dominated by astrophorids.
Źródło:
Acta Geologica Polonica; 2021, 71, 2; 175-198
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Groundwater arsenic contamination in West Bengal: current scenario, effects and probable ways of mitigation
Autorzy:
Dey, T.K.
Banerjee, P.
Bakshi, M.
Kar, A.
Ghosh, S,
Powiązania:
https://bibliotekanauki.pl/articles/11026.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
ground water
arsenic
water contamination
West Bengal
mitigation
human health
Opis:
During the past two decades, Arsenic (As) contamination via groundwater has become a serious issue worldwide and is now a major concern in the Indo-Bangladesh Gangetic delta. Arsenic enters human body through contaminated groundwater consumed as drinking water. Food safety in this region is also facing severe consequences as bio-accumulation of Arsenic is occurring in food crops irrigated with As-contaminated water. Chronic exposure to Arsenic can cause not only cancerous and non-cancer health effects. Reports suggest that about 20 % population in West Bengal is highly affected. Various techniques are being introduced to provide arsenic-free drinking water at an affordable cost. But a rigorous change in habit and mind set for procuring safe drinking water in those surviving in As-contaminated zones is the most essential step towards curbing the fatal consequences of As exposure. Harvesting rain water and utilization of proper purification techniques can be considered a possible alternative of safe drinking water.
Źródło:
International Letters of Natural Sciences; 2014, 08, 1
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Granulometric and facies analysis of Middle–Upper Jurassic rocks of Ler Dome, Kachchh, western India: an attempt to reconstruct the depositional environment
Autorzy:
Ghaznavi, Asma A.
Quasim, M. A.
Ahmad, A. H. M.
Ghosh, Sumit K.
Powiązania:
https://bibliotekanauki.pl/articles/94565.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
grain size analysis
hydrodynamic conditions
microtexture
sedimentation
marine environment
analiza wielkości ziarna
warunki hydrodynamiczne
mikrotekstura
sedymentacja
środowisko morskie
Opis:
Grain size analysis is an important sedimentological tool used to unravel hydrodynamic conditions, mode of transportation and deposition of detrital sediments. For the present study, detailed grain size analysis was carried out in order to decipher the palaeodepositional environment of Middle–Upper Jurassic rocks of the Ler Dome (Kachchh, western India), which is further reinforced by facies analysis. Microtextures were identified as grooves, straight steps and V-shaped pits, curved steps and solution pits suggesting the predominance of chemical solution activity. Grain size statistical parameters (Graphic and Moment parameters) were used to document depositional processes, sedimentation mechanisms and conditions of hydrodynamic energy, as well as to discriminate between various depositional environments. The grain size parameters show that most of the sandstones are medium- to coarse-grained, moderately to well sorted, strongly fine skewed to fine skewed and mesokurtic to platykurtic in nature. The abundance of medium- to coarse-grained sandstones indicates fluctuating energy levels of the deposition medium and sediment type of the source area. The bivariate plots show that the samples are mostly grouped, except for some samples that show a scattered trend, which is either due to a mixture of two modes in equal proportion in bimodal sediments or good sorting in unimodal sediments. The linear discriminant function analysis is predominantly indicative of turbidity current deposits under shallow-marine conditions. The C-M plots indicate that the sediments formed mainly by rolling to bottom suspension and rolling condition in a beach subenvironment. Log probability curves show that the mixing between the suspension and saltation populations is related to variable energy conditions.
Źródło:
Geologos; 2019, 25, 1; 51-73
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of Jute Retting on Native Fish Diversity and Aquatic Health of Roadside Transitory Water Bodies: an Assessment in Eastern India
Autorzy:
Ghosh, D.
Biswas, J. K.
Powiązania:
https://bibliotekanauki.pl/articles/125476.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
transitory water bodies
physicochemical analysis
fish diversity
Shannon-Wiener Index
jute retting
Opis:
Roadside transitory water bodies being manmade depressions have a great ecological and socio-economic importance from years. The effects of agricultural runoffs, jute retting, macro-phytes infestations and inadequate rainfall in changed climate often degrade transitory water bodies’ environment while the biodiversity have impacted severely because of population pressure, over exploitation and indiscriminate use of fine meshed fishing gears as a whole. Physico-chemical and biological analysis with fish species composition, relative abundance, diversity indices like species richness, evenness and Shannon-Wiener index were carried out for pre-, during and post-jute retting season and for year mean as a whole to assess impact of jute retting on the roadside transitory water body’s environmental health and indigenous fish diversity at Sahebnagar village in Nadia District, India. All the physico-chemical parameters barring biochemical oxygen demand and water transparency remained more or less same or marginally got little changed during those three seasons. As much as 19 native fish species with varied relative abundances and dominances were identified. Jute retting impacted lower native fish diversity indices like Shannon-Wiener index values (1.94 to 2.68) clearly indicated poor to moderate pollution status of the transitory water body in that area during monsoon in particular and throughout the year in general. So we opined there should be some control over the intense jute retting in the road side transitory water bodies for sustainable management of these manmade resources.
Źródło:
Journal of Ecological Engineering; 2015, 16, 4; 14-21
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of Jute Retting on Phytoplankton Diversity and Aquatic Health: Biomonitoring in a Tropical Oxbow Lake
Autorzy:
Ghosh, D.
Biswas, J. K.
Powiązania:
https://bibliotekanauki.pl/articles/123191.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
biomonitoring
oxbow lake health
jute retting
phytoplankton
diversity index
Opis:
Phytoplankton acts as a primary producer and biological filter of aquatic ecosystem. Jute retting during monsoon is a common anthropological activity in the rural Bengal. Quantitative seasonal bio-monitoring of phytoplankton community composition with relative abundance and its diversity indices was carried out in this study from April 2013 to March 2014 to assess water quality and the impact of jute retting on phytoplankton diversity of a tropical fresh water oxbow lake in Nadia district of India. We recorded a total of 34 genera of 5 distinct classes, Chlorophyceae (15), Bacillariophyceae (13), Cyanophyceae (4), Dinophyceae (1) and Euglenophyceae (1). Members of Chlorophyceae dominated throughout the year. Unlike Cyanophyceae, Bacillariophyceae was found to be significantly increased during monsoon when compared to the rest of the year. Average phytoplankton density was highest in post-monsoon (8760/L) followed by monsoon (4680/L) and pre-monsoon (3650/L). Owing to the dominance of class Chlorophyceae and Bacillariophyceae we found this lake to be oligotrophic to mesotrophic. Indices values of genera richness, Shannon-Wiener, evenness and Simpson’s diversity reached their lowest 14, 1.61, 0.61 and 0.68 in monsoon and highest 23, 2.42, 0.77 and 0.86 in post monsoon respectively. The lowest diversity values during monsoon clearly suggested that the selected lake has highest anthropogenic pollution due to jute retting which impacted significantly on phytoplankton diversity. Therefore, the lake is not conducive for fish growth especially during monsoon and we opine that there is a need to regulate jute retting process, intensity and its density in the lake during the monsoon to ensure enhanced biodiversity for sustainable management and conservation of aquatic environment of this Oxbow lake.
Źródło:
Journal of Ecological Engineering; 2015, 16, 5; 15-25
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modern Alphaset (APNB) Flexible Formulations-Enhanced Performance
Autorzy:
Ghosh, D. K.
Powiązania:
https://bibliotekanauki.pl/articles/1837863.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
make molds and cores
sand binder
resin performance
alkaline phenolic no-bake
APNB
wytwarzenie form i rdzeni
spoiwo piaskowe
właściwości żywic
Opis:
APNB (alkaline phenolic no bake), widely known as Alphaset is one of the major sand binder systems used in foundries to make molds and cores without application of heat or gas. This is a two part system comprising of a phenol-formaldehyde resin in alkaline medium as binder and range of esters of dibasic acids and/or polyhydric alcohols as hardeners. Resin performance varies depending upon formulations. Major variables in formulations are mole ratio of phenol: formaldehyde, total alkali content, ratio of two alkalis (NaOH & KOH) and molecular weight of polymers i.e. chain length. In present work, one mole ratio of phenol & formaldehyde has been chosen to prepare 8 resins [...].
Źródło:
Archives of Foundry Engineering; 2020, 20, 4; 18-28
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Molding Sand Technology Between Alphaset (APNB) and Furan (FNB)
Autorzy:
Ghosh, Dipak K.
Powiązania:
https://bibliotekanauki.pl/articles/381891.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Alphaset
Furan
foundries
molding sand
heat strength
residual strength
gases
environment
odlewanie
piasek formierski
wytrzymałość cieplna
Opis:
The paper focuses on investigation of properties of two most widely used self-set sand binder systems APNB and FNB across the Globe, for making molds and cores in foundries to produce castings of different sizes involving wide range of metals and alloys, ferrous and nonferrous. This includes study of compression strength values of samples made out of molding sand at different binder addition level using new, mechanically reclaimed (MR) and thermally reclaimed (TR) sand. Strength values studied include dry strength (at room temperature) at specified intervals simulating different stages of mold handling, namely stripping and pre heating, followed by degraded strength after application of thinner based zircon wash by brush, subsequent lighting of, then checking strength both in warm (degraded strength) & cold (recovered strength) conditions. Throughout the cycle of mold movement from stripping to knock out, strength requirements can be divided into two broad classifications, one from stripping to closing (dry strength) and another from pouring to knock out (hot & retained strength). Although the process for checking of dry strength are well documented, no method using simple equipments for checking hot & retained strength are documented in literature. Attempts have been made in this paper to use some simple methods to standardize process for checking high strength properties using ordinary laboratory equipments. Temperature of 450°C has been chosen by trial & error method to study high temperature properties to get consistent & amplified values. Volume of gases generated for both binders in laboratory at 850°C have also been measured. Nature of gases including harmful BTEX and PAH generated on pyrolysis of FNB and APNB bonded sands are already documented in a publication [1]. This exercise has once again been repeated in same laboratory, AGH University, Poland with latest binder formulations in use in two foundries in India.
Źródło:
Archives of Foundry Engineering; 2019, 4; 11-20
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies on Aluminized, High Burning Rate, Butacene® Based, Composite Propellants
Autorzy:
Ghosh, K.
Behera, S.
Kumar, A.
Padale, B. G.
Deshpande, D. G.
Gupta, M.
Powiązania:
https://bibliotekanauki.pl/articles/358702.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
Butacene®
ferrocene
pressure exponent
Opis:
This paper reports on a Butacene® based composite propellant with high burning rate. The effect of replacing HTPB with Butacene® on the physical, mechanical and ballistic properties, and sensitivity towards impact and friction, has been studied. The ballistic properties were evaluated as burning rates at various pressures (7-11 MPa), pressure exponents, ignition temperatures etc. As expected, a remarkable enhancement in burning rate at low pressures was observed with increasing percentage of Butacene®. Comparatively lower n-values were observed for compositions containing Butacene® than for HTPB based propellants. The sensitivity of Butacene® based compositions, in terms of impact and friction, was found to be increased with an increasing percentage of Butacene®.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 3; 323-333
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantitative analysis of α-CL-20 polymorphic impurity in ε-CL-20 using Dispersive Raman Spectroscopy
Autorzy:
Ghosh, M.
Venkatesan, V.
Sikder, N.
Sikder, A. K.
Powiązania:
https://bibliotekanauki.pl/articles/951498.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
CL-20
polymorphs
α-CL-20 impurity
Dispersive Raman Spectroscopy
Opis:
α-CL-20 polymorphic impurity in ε-CL-20 studies have been carried out using Dispersive Raman Spectroscopy. ε-, β-, α- and γ-CL-20 polymorphs were produced using crystallization methods with sample recovery from the solution being >90%, and chemical purity of about 99%. The polymorphs prepared were characterized using Dispersive Raman Spectroscopy over the Raman shift region of 100-3500 cm-1 using a 514 nm argon ion laser. The experimental studies were supported by ab initio computations performed at B3LYP level using a 6-31+G** basis set. The computed vibrational frequencies of the CL-20 conformers correspond to the ε, β and α or γ-CL-20 polymorphs when compared with the observed frequencies. α-CL-20 shows a distinct feature at 280 cm-1 as compared with those of the ε-CL-20 polymorph. Using Dispersive Raman Spectroscopy, a linear relationship was demonstrated for the absolute peak height and absolute peak area ratio of α-CL-20 versus the weight percent of α-CL-20. This method enables a detection limit of this polymorphic impurity down to 2 wt%.
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 3; 419-438
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new circuit topology using Z-source resonant inverter for high power contactless power transfer applications
Autorzy:
Ghosh, P. C.
Sadhu, P. K.
Ghosh, A.
Pal, N.
Powiązania:
https://bibliotekanauki.pl/articles/141006.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
contactless power transfer
mutual inductance
magnetic coupling coefficient
Z-source
resonant inverter
Opis:
In this study, a new circuit topology using a Z-source resonant inverter (ZSRI) for high power applications in large-air-gap contactless power transfer (CPT) systems, has been investigated. The main shortcoming of a large-air-gap CPT system is the poor power transfer efficiency due to low magnetic coupling. In order to minimize this shortcoming and to improve the overall performance of the system by boosting the power transfer capability, in this paper a CPT system with the newly developed circuit topology using high frequency Z-source resonant inverter has been proposed. Using the newly developed circuit topology for the CPT system, it has been observed that the overall performance of the system has been improved to a reasonable level with a purely sinusoidal resonant current flowing through the primary side. Therefore, no harmonics will be injected into the source. The proposed CPT system with an air gap of 16 cm and a misalignment of 3 cm has been simulated using the Maxwell finite element tool and Simplorer circuit simulation software for an output power of 2 kW.
Źródło:
Archives of Electrical Engineering; 2017, 66, 4; 843-854
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
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:
Pilot Agent-Driven Wireless Acoustic Sensor Network for Uninterrupted Data Transmission
Autorzy:
Ghosh, Utpal
Mondal, Uttam K.
Powiązania:
https://bibliotekanauki.pl/articles/27312943.pdf
Data publikacji:
2023
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
agent technology
audio signal
multipath routing
partial topology
WASN
Opis:
Wireless acoustic sensor networks (WASN) usually demand uninterrupted and reliable data transmissions and an efficient path from the source nodes to the destination nodes, thus ensuring reliable delivery of sensitive or critical data with the use of multipath routing protocols. This paper presents a novel agent-driven WASN relying on a set of static and mobile agents. In the proposed technique, the location address is functioned into the operating node and the destination node. Calculations of the midpoint between the operating and the destination nodes are followed by identifying the shortest path based on a reference axis, using a mobile agent and a location address. Such an approach aims to ensure maximum utilization of the communicating paths. Based on the information concerning partial topology of the network, the destination node computes the weight factor and multiple paths using node distances, energy ratios and efficiencies of specific links. Then, the destination node selects the appropriate path from the multiple paths available, to transmit the data. This article also analyzes the performance of the proposed system with various parameters taken into consideration and shows its efficiency in comparison to other existing techniques.
Źródło:
Journal of Telecommunications and Information Technology; 2023, 4; 53--60
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
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

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