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Advances in Materials Physics and Chemistry 2013年第2期3卷 133-145页

作者： Avijit Nandi Chandana Sen debashis mallick Randhir K. Sinha Chittaranjan Sinha Department of Chemistry Inorganic Chemistry Section Jadavpur University Kolkata India Department of Chemistry Mrinalini Datta Mahavidyapith Birati India

Photochromism is the reversible structural change of the molecules upon light irradiation having different spectral pattern before and after irradiation. Liquid crystal (LC) is a long-range orientational order of the molecules in between solid and isotropic liquid phases which share the properties of the crystal and liquid phases. 1-Alkyl-2-(ary-lazo)imidazoles, (Raai-CnH2n+1, R = H, Me and n = 10, 12, 14, 16, 18, 20, 22) exhibits photochromism and two of them (Haai-C18H37 and Haai-C22H45) show Liquid crystal (LC) properties. One of these compounds, Meaai-C16H33 is structurally characterized by single crystal X-ray diffraction study. The compounds upon irradiation with UV light show E-to-Z isomerisation. Quantum yields (φE→Z) of E-to-Z isomerisation vary with the molar mass of the compounds. The reverse transformation, Z-to-E, is recorded in thermal condition. The activation energy (Ea) of isomerisation is determined by the controlled temperature reaction. Liquid crystal property of the molecules is examined by polarizing optical microscopy (POM) and DSC. The carbon chain length n = 18 shows nematic (N)-isotropic (I) phase transition and an unknown Smectic (Sm) phase is observed with n = 22 on heating cycle.

关键词： Arylazoimidazoles Structure Photochromism Liquid Crystal Nematic-Isotropic Phase Transition Smectic Phase

Study of Secondary Cosmic Rays and Astronomical X-Ray Sources using Small Stratospheric Balloons

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Research in Astronomy and Astrophysics 2024年第6期24卷 94-109页

作者： Rupnath Sikdar Sandip K.Chakrabarti debashis Bhowmick Indian Centre for Space Physics 466BarakholaSingabari RoadNetai NagarKolkata700099West BengalIndia

The X-ray sources of the universe are extraterrestrial in nature which emit X-ray *** closest strong X-ray source is the Sun,which is followed by various compact sources such as neutron stars,black holes,the Crab pulsar,*** this paper,we analyze the data received from several low-cost lightweight meteorological balloon-borne missions launched by the Indian Centre for Space *** main interest is to study the variation of the vertical intensity of secondary cosmic rays,the detection of strong X-ray sources,and their spectra in the energy band of^(1)0–80 keV during the complete *** to the lack of an onboard pointing system,low exposure time,achieving a maximum altitude of only~42 km,and freely rotating the payload about its axis,we modeled the background radiation flux for the X-ray detector using physical *** also present the source detection method,observation of the pulsation of the Crab(^(3)3 Hz),and spectra of some sources such as the quiet Sun and the Crab pulsar.

关键词： X-rays:stars balloons instrumentation:detectors

Dynamics of a delay-induced prey-predator system with interaction between immature prey and predators

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International Journal of Biomathematics 2024年第2期17卷 139-176页

作者： Soumik Pandey Abhijit Sarkar debashis Das Sarbani Chakraborty Department of Mathematics West Bengal State University Barasat-7000126West BengalIndia Department of Basic Science&Humanities JIS College of Engineering Kalyani-741235West BengalIndia

In biological pest control systems,several pests(including insects,mites,weeds,etc.)are controlled by biocontrol agents that rely primarily on *** this biocontrol management ecology,we have created a three-tier prey-predator model with prey phase structure and predator gestation *** studies have demonstrated that predators with Holling type-II functional responses sometimes consume immature prey.A study of the well-posedness and local bifurcation(such as saddle-node and transcritical)near the trivial and planer equilibrium points is carried *** any time lag,the prey development coeficient has a stabilizing impact,while increasing attack rate accelerates *** transformation rate and handling time are shown to cause multiple stability switches in the *** results demonstrate time delay is the key destabilizer that destroys *** model can replicate more realistic events by including time-dependent factors and exploring the dynamic behavior of nonautonomous *** the presence of time delay,sufficient conditions of permanence and global attractivity of the nonautonomous system are ***,MATLAB simulations are performed to validate the analytical findings.

关键词： Holling type-II functional response stage-structure bifurcation time delay seasonality

Geochemical and petrological studies of high sulfur coal and overburden from Makum coalfield (Northeast India) towards understanding and mitigation of acid mine drainage

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International Journal of Coal Science & Technology 2024年第1期11卷 133-147页

作者： Angana Mahanta debashis Sarmah Nilotpol Bhuyan Monikankana Saikia Sarat Phukan K.S.V.Subramanyam Ajit Singh Prasenjit Saikia Binoy K.Saikia Coal and Energy Division CSIR-North East Institute of Science and TechnologyJorhatAssam785006India Academy of Scientific&Innovative Research(AcSIR) Ghaziabad201002India Department of Geological Sciences Gauhati UniversityGuwahatiAssam781014India Geochemistry Division CSIR-National Geophysical Research InstituteUppal RoadHyderabad500007India

Opencast coal mining produces trash of soil and rock containing various minerals,that are usually dumped nearby the abandoned sites which causes severe environmental concern including the production of acid mine drainage(AMD)through oxidation pyrite *** current study entailed assessing the potential production of AMD from an opencast coal mining region in Northeast part of *** order to have a comprehensive overview of the AMD problem in Makum coalfield,the physico-chemical,geochemical,and petrological characteristics of the coal and overburden(OB)samples collected from the Makum coalfield(Northeast India)were thoroughly *** maceral compositions reveal that coal features all three groups of macerals(liptinite,vitrinite,and inertinite),with a high concentration of liptinite indicating the coal of perhydrous,thereby rendering it more ***(FeS_(2))oxidation kinetics were studied by conducting the aqueous leaching experiments of coal and(OB)samples to interpret the chemical weathering under controlled laboratory conditions of various temperature and time periods,and to replicate the actual mine site *** coupled plasma-optical emission spectroscopy(ICP-OES)was operated to detect the disposal of some precarious elements from coal and OB samples to the leachates during our controlled leaching *** Rare earth element(REE)enrichment in the samples shows the anthropogenic incorporation of the REE in the coal and *** experiments reveal the change in conductivity,acid producing tendency,total dissolved solid(TDS),total Iron(Fe)and dissolved Sulfate(SO_(4)^(2−))ions on progress of the leaching ***,the discharge of FeS_(2) via atmospheric oxidation in laboratory condition undergoes a significant growth with the rise of temperature of the reaction systems in the environment and follows pseudo first order kinetics.A bio-remediative strategies is also reported in this paper to mitigate AMD water by

关键词： Opencast mining Pyrite oxidation Coal geochemistry Coal petrology Rare earth elements AMD remediation

Next Generation Nutrition: Genomic and Molecular Breeding Innovations for Iron and Zinc Biofortification in Rice

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Rice science 2024年第5期31卷 526-544,I0029,I0030页

作者： Kunhikrishnan Hemalatha DHANYALAKSHMI Reshma MOHAN Sasmita BEHERA Uday Chand JHA debashis MOHARANA Ahalya BEHERA Sini THOMAS Preman Rejitha SOUMYA Rameswar Prasad SAH Radha BEENA Department of Plant Physiology College of AgriculturePadannakkadKerala Agricultural UniversityKerala 671314India Department of Plant Physiology College of AgricultureVellayaniKerala Agricultural UniversityKerala 695522India Crop Improvement Division India Council of Agricultural Research-National Rice Research InstituteOdisha 7530006India Department of Plant Breeding and Genetics Indian Institute of Pulse ResearchKanpur 208024India Department of Plant Physiology College of AgricultureKumarakomKerala Agricultural UniversityKerala 686563India

Global efforts to address malnutrition and hidden hunger, particularly prevalent in low- and middle-income countries, have intensified, with a focus on enhancing the nutritional content of staple crops like rice. Despite serving as a staple for over half of the world's population, rice falls short in meeting daily nutritional requirements, especially for iron(Fe) and zinc(Zn). Genetic resources, such as wild rice species and specific rice varieties, offer promising avenues for enhancing Fe and Zn content. Additionally, molecular breeding approaches have identified key genes and loci associated with Fe and Zn accumulation in rice grains. This review explores the genetic resources and molecular mechanisms underlying Fe and Zn accumulation in rice grains. The functional genomics involved in Fe uptake, transport, and distribution in rice plants have revealed key genes such as OsFRO1, OsIRT1, and OsNAS3. Similarly, genes associated with Zn uptake and translocation, including OsZIP11 and OsNRAMP1, have been identified. Transgenic approaches, leveraging transporter gene families and genome editing technologies, offer promising avenues for enhancing Fe and Zn content in rice grains. Moreover, strategies for reducing phytic acid(PA) content, a known inhibitor of mineral bioavailability, have been explored, including the identification of low-PA mutants and natural variants. The integration of genomic information, including whole-genome resequencing and pan-genome analyses, provides valuable insights into the genetic basis of micronutrient traits and facilitates targeted breeding efforts. Functional genomics studies have elucidated the molecular mechanisms underlying Fe uptake and translocation in rice. Furthermore, transgenic and genome editing techniques have shown promise in enhancing Fe and Zn content in rice grains through the manipulation of key transporter genes. Overall, the integration of multi-omics approaches holds significant promise for addressing global malnutri

关键词： biofortification grain quality iron phytic acid rice zinc

Investigating the Dominant Source for the Generation of Gravity Waves during Indian Summer Monsoon Using Ground-based Measurements

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Advances in Atmospheric Sciences 2013年第1期30卷 153-166页

作者： debashis NATH 陈文 Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of Sciences

Over the tropics, convection, wind shear （i.e., vertical and horizontal shear of wind and/or geostrophic adjustment comprising spontaneous imbalance in jet streams） and topography are the major sources for the generation of gravity waves. During the summer monsoon season （June August） over the Indian subcontinent, convection and wind shear coexist. To determine the dominant source of gravity waves during monsoon season, an experiment was conducted using mesosphere-stratosphere-troposphere （MST） radar situated at Gadanki （13.5°N, 79.2°E）, a tropical observatory in the southern part of the Indian subcontinent. MST radar was operated continuously for 72 h to capture high-frequency gravity waves. During this time, a radiosonde was released every 6 h in addition to the regular launch （once daily to study low-frequency gravity waves） throughout the season. These two data sets were utilized effectively to characterize the jet stream and the associated gravity waves. Data available from collocated instruments along with satellite-based brightness temperature （TBB） data were utilized to characterize the convection in and around Gadanki. Despite the presence of two major sources of gravity wave generation （i.e., convection and wind shear） during the monsoon season, wind shear （both vertical shear and geostrophic adjustment） contributed the most to the generation of gravity waves on various scales.

关键词： convection wind shear gravity waves MST radar radiosonde

Understanding the influence of petrographic parameters on strength of differently sized shale specimens using XRD and SEM

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International Journal of Mining Science and Technology 2021年第5期31卷 953-961页

作者： debashis Das Brijes Mishra Neel Gupta RESPEC LexingtonKY 40508USA West Virginia University MorgantownWV 26506USA

Ground failure is a major contributor to fatalities in underground mines in the *** coal mines in the Northern Appalachian have weak roof rock composed of shale,which is prone to failure under high horizontal *** the relationship among strength,specimen size and rock petrographic parameters is essential for developing an effective ground control *** effect studies have found that rock strength varies with specimen *** paper attempts to understand this strength variation using three specimen sizes(254-mm,508-mm,and 762-mm).The specimen strength was measured and the major petrographic parameters affecting the strength,namely grain size,grain shape,quartz content,clay content,*** analyzed using X-ray diffraction(XRD)and scanning electron microscopy(SEM).The petrographic parameters were then correlated with the strength of the three differently sized *** results showed that 508-mm specimen had the lowest *** content of the 508-mm specimen was lower than that of 254-mm and 762-mm *** content and average grain size of the 508-mm specimen were higher than those of 254-mm and 762-mm *** results clearly show that grain size,quartz content and clay content contribute to strength variation observed in differently sized shale specimens.

关键词： Shale strength XRD(X-ray diffraction) SEM(scanning electron microscopy) Grain size Quartz content Grain shape

Quantum-dot cellular automata based reversible low power parity generator and parity checker design for nanocommunication

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Frontiers of Information Technology & Electronic Engineering 2016年第3期17卷 224-236页

作者： Jadav Chandra DAS debashis DE Department of Computer Science and Engineering West Bengal University of Technology Department of Physics University of Western Australia

Quantum-dot cellular automata （QCA） is an emerging area of research in reversible computing. It can be used to design nanoscale circuits. In nanocommunication, the detection and correction of errors in a received message is a major factor. Besides, device density and power dissipation are the key issues in the nanocommunication architecture. For the first time, QCA-based designs of the reversible low-power odd parity generator and odd parity checker using the Feynman gate have been achieved in this study. Using the proposed parity generator and parity checker circuit, a nanocommunication architecture is pro- posed. The detection of errors in the received message during transmission is also explored. The proposed QCA Feynman gate outshines the existing ones in terms of area, cell count, and delay. The quantum costs of the proposed conventional reversible circuits and their QCA layouts are calculated and compared, which establishes that the proposed QCA circuits have very low quantum cost compared to conventional designs. The energy dissipation by the layouts is estimated, which ensures the possibility ofQCA nano-device serving as an alternative platform for the implementation of reversible circuits. The stability of the proposed circuits under thermal randomness is analyzed, showing the operational efficiency of the circuits. The simulation results of the proposed design are tested with theoretical values, showing the accuracy of the circuits. The proposed circuits can be used to design more complex low-power nanoscale lossless cation architecture such as nano-transmitters and nano-receivers

关键词： Quantum-dot cellular automata (QCA) Parity generator Parity checker Feynman gate Nanocommunication Powerdissipation

A Novel Approach for Mitigating Power Quality Issues in a PV Integrated Microgrid System Using an Improved Jelly Fish Algorithm

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Journal of Bionic Engineering 2023年第1期20卷 30-46页

作者： Swati Suman debashis Chatterjee Rupali Mohanty Department of Electrical Engineering Jadavpur UniversityKolkataWest Bengal700032India

A two-step methodology was used to address and improve the power quality concerns for the PV-integrated microgrid system. First, partial shading was included to deal with the real-time issues. The Improved Jelly Fish Algorithm integrated Perturb and Obserb (IJFA-PO) has been proposed to track the Global Maximum Power Point (GMPP). Second, the main unit-powered via DC–AC converter is synchronised with the grid. To cope with the wide voltage variation and harmonic mitigation, an auxiliary unit undergoes a novel series compensation technique. Out of various switching approaches, IJFA-based Selective Harmonic Elimination (SHE) in 120° conduction gives the optimal solution. Three switching angles were obtained using IJFA, whose performance was equivalent to that of nine switching angles. Thus, the system is efficient with minimised higher-order harmonics and lower switching losses. The proposed system outperformed in terms of efficiency, metaheuristics, and convergence. The Total Harmonic Distortion (THD) obtained was 1.32%, which is within the IEEE 1547 and IEC tolerable limits. The model was developed in MATLAB/Simulink 2016b and verified with an experimental prototype of grid-synchronised PV capacity of 260 W tested under various loading conditions. The present model is reliable and features a simple controller that provides more convenient and adequate performance.

关键词： Harmonic mitigation Selective harmonic elimination pulse width modulation inverters Search-based optimization techniques Bionic algorithm Total harmonic distortion Modulation indices

Impact of Planetary Wave Reflection on Tropospheric Blocking over the Urals–Siberia Region in January 2008

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Advances in Atmospheric Sciences 2016年第3期33卷 309-318页

作者： debashis NATH Wen CHEN Center for Monsoon System Research Institute of Atmospheric Physics Chinese Academy of Sciences

Planetary wave reflection from the stratosphere played a significant role in changing the tropospheric circulation pattern over Eurasia in mid-January 2008. We studied the 2008 event and compared with composite analysis （winters of 2002/2003, 200412005, 200612007, 200712008, 201012011 and 2011/2012）, when the downward coupling was stronger, by employing time-lagged singular value decomposition analysis on the geopotential height field. In the Northern Hemisphere, the geopo- tential fields were decomposed into zonal mean and wave components to compare the relative covariance patterns. It was found that the wavenumber 1 （WN1） component was dominant compared with the wavenumber 2 （WN2） component and zonal mean process. For the WNI field, the covariance was much higher （lower） for the negative （positive） lag, with a prominent peak around ＋15 days when the leading stratosphere coupled strongly with the troposphere. It contributed to the downward coupling due to reflection, when the stratosphere exhibited a partially reflective background state. We also analyzed the evolution of the WNI anomaly and heat flux anomaly, both in the troposphere and stratosphere, during January- March 2008. The amplitude of the tropospheric WN 1 pattern reached a maximum and was consistent with a downward wave coupling event influenced by the stratospheric WN1 anomaly at 10 hPa. This was consistent with the reflection of the WN1 component over Eurasia, which triggered an anomalous blocking high in the Urals-Siberia region. We further clarified the impact of reflection on the tropospheric WNI field and hence the tropospheric circulation pattern by changing the propagation direction during and after the event.

关键词： planetary wave reflection singular value decomposition (SVD) Eliassen-Palm (EP) flux blocking circulation