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Development of a new coated electrode with low nickel content for welding ductile iron and its response to austempering

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International Journal of Minerals,Metallurgy and Materials 2018年第9期25卷 1090-1103页

作者： tapan Sarkar Ajit Kumar Pramanick tapan Kumar Pal Akshay Kumar Pramanick Welding Technology Centre Jadavpur University Department of Forge Technology NIFFT

Coated Electrodes with small amounts of nickel were developed for welding ductile iron(DI) and conversion of the same into austempered ductile iron(ADI) after austempering. Among six electrodes, Trials 3 and 4 were selected for establishing crack-free weld deposits via preheating and post-weld heat treatment. Austenitization was performed at 900°C for 2 h and austempering at 300 or 350°C for three different holding times to observe the results of austempering with respect to the microstructure, hardness, and austempering kinetics of the samples. The microstructures of the weld deposits showed needle-like bainitic ferrite with small amounts of retained austenite when treated at 300°C and feathery bainitic ferrite with large amounts of retainedaustenite when treated at 350°C. The electrode labeled with Trial 3 revealed greater austenite contents than that labeled with Trial 4 when treated with a 2 h holding time regardless of the austempering temperature applied. The transformation rate of the bainitic ferrite of Trial 3 was relatively higher than that of Trial 4 and showed a lower rate constant, leading to a higher diffusion rate of carbon in austenite.

关键词： electrode development microstructure XRD analysis transformation kinetic microhardness

Role of Microstructural Constituents on Surface Crack Formation During Hot Rolling of Standard and Low Nickel Austenitic Stainless Steels

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Acta Metallurgica Sinica(English Letters) 2013年第2期26卷 206-216页

作者： Manidipto Mukherjee tapan Kumar Pal Welding Technology Centre Metallurgical and Material Engineering Department Jadavpur University

The effect of alloy segregation and delta （δ） ferrite contents on surface cracking of three standard （i.e. AISI 304L, AISI 310S and AISI 321） and two low nickel （i.e. LNi-1 and LNi-0.3） austenitic stainless steels （ASS） during hot roiling was investigated using optical microscopy （OM）, automatic image analyzer, scanning electron microscopy （SEM）, energy dispersive X-ray spectroscopy （EDX） and electron probe micro analyzer （EPMA）. It was observed that the amount of 6-ferrite varied among different grades and also distributed heterogeneously across the width of the steel plates. In general, low nickel ASS showed higher amount of 6-ferrite compared to the standard ASS grades. The tendency to surface cracking during hot rolling gradually increased with increasing 6-ferrite content. Interestingly, carbon and nitrogen exerted maximum effect on 6-ferrite formation. The higher carbon and nitrogen content in the steel decreased 6-ferMte content. In addition, the segregation of Cu and Mn plays significant role in low nickel ASS and Ni-Cr in case of standard ASS has profound effect on surface cracking of the steel plates. A possible cause of surface crack formation/origination in steel plates during hot rolling was discussed.

关键词： Austenitic stainless steel Hot rolling Surface cracking Alloy segregation δ ferrite

High-cycle fatigue behavior of friction stir butt welded 6061 aluminium alloy

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Transactions of Nonferrous Metals Society of China 2014年第3期24卷 648-656页

作者： Hrishikesh DAS Debayan chakRABORTY tapan KUMAR PAL Welding Technology Centre Metallurgical and Material Engineering DepartmentJadavpur University

Friction stir welding （FSW） of 6061 aluminium alloy butt joint was carried out at each rotation speed of 600, 800, 1000, 1200 r/min for two different travel speeds, 80 and 100 mm/min, at a constant probe depth of 1.85 mm. The calculated energy input based on the FSW parameters studied shows that the ultimate tensile strength （UTS） of the butt joint is obtained within a certain range of energy input of 297 kJ to 354 kJ out of total range of energy input studied from 196 kJ to 405 kJ. The fatigue behaviors of high-strength and low-strength joints performed at different stress ratios, i.e., 0.5, 0.3, 0.1, -0.3, -0.5, indicate that the fatigue behaviors of both the welds are sensitive to the microstructural features, such as stir zone （SZ）, thermo mechanically affected zone （TMAZ） and heat affected zone （HAZ）. The observed fatigue strengths were discussed in terms of the microstructure, crack path behavior and fracture surface.

关键词： Al alloy friction stir welding (FSW) high cycle fatigue stress ratio (R-ratio) crack path

Full-Duplex Cooperative Relaying with Non-Linear Energy Harvesting for Vehicular Communication

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Journal of Communications and Information Networks 2023年第4期8卷 369-377页

作者： Vaijayanti Panse tapan Kumar Jain Indian Institute of Information Technology Nagpur441108India

This paper analyses the performance of fullduplex(FD)dual-hop vehicular cooperative network with decode-and-forward(DF)*** FD relay nodes,we examine the effects of non-linear hybrid power time splitting(PTS)based energy harvesting(EH).All three nodes—source(S),relay(R),and destination(D)are assumed to be moving *** expressions for the system's outage probability(OP)over double(cascaded)Rayleigh fading channels are *** also analyse the impact of residual self-interference(RSI)caused at FD relay on system's *** compare the performance of system with two relay selection techniques,namely,maximum channel gain-based(Max-G)relay selection and minimum RSI-based(Min-SI)relay *** paper considers the joint effect of time splitting ratio and self-interference cancellation(SIC)level to find the optimum EH ***,the effect of time splitting ratio and average signal-to-noise ratio(SNR)on outage and throughput performance of the system are also investigated in this *** derived expressions are validated through Monte Carlo simulations.

关键词： Cooperative communication vehicular networks energy harvesting full-duplex outage probability

Forest-based betel leaf and betel nut farming of the Khasia indigenous People in Bangladesh: approach to biodiversity conservation in Lawachara National Park(LNP)

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Journal of Forestry Research 2014年第2期25卷 419-427页

作者： Md. Jahirul Islam tapan Kumar Nath Bangladesh Planning Commission Institute of Forestry and Environmental Sciences University of Chittagong

An exploratory survey was conducted among the Khasia living in Lawachara National Parkt （LNP） to investigate their depend- ency on the protected area （PA） for livelihoods, betel leaf hill farming, traditional forest conservation and perceptions of the PA, Field data were collected by interviewing 48 household heads from two villages （punjis） located inside the LNP and visiting their farms.： The economy of the Khasia was forest-based. They were largely dependent on betel leaf hill farming in LNP and nearly 71% of their mean annual income was de- rived from this irrespective of farmer category. On average, about 14% of the incomes of the poorer farmers came from forest produce followed by 10% and 6% for medium and rich farmers respectively. Hills and forests were the foundations of their lives and livelihoods, and LNP was the life-blood of Khasia survival. As a sustainable production system, this farming practice plays a vital role in conserving biodiversity in LNP and might be replicated elsewhere.

关键词： Bangladesh indigenous people Khasia livelihoods betel leaf fanning protected area management

Review of System Strength and Inertia Requirements for the National Electricity Market of Australia

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CSEE Journal of Power and Energy Systems 2019年第3期5卷 295-305页

作者： Huajie Gu Ruifeng Yan tapan Saha Power and Energy Systems Research Group School of Information Technology and Electrical EngineeringThe University of QueenslandBrisbane St LuciaQLD 4072Australia

Synchronous generators(SGs)are still making major contributions to the re-stabilization of a power system following voltage/frequency disturbances,attributed to their inherent capability of providing system strength and ***,SGs powered by fossil fuels are operating to a lesser extent and scheduled for decommissioning in the National Electricity Market(NEM)of Australia due to the accelerating increase of low bidding priced asynchronous generation of wind and solar,which leads to the reduction and even in some cases,a shortage of system strength and *** paper comprehensively reviews the requirements of system strength and inertia in the NEM from an operational security *** is the first country that established the regulation rules of system strength and inertia to accommodate issues of an emerging high penetration level of non-synchronous renewable generation.

关键词： Inertia power system renewable energy system strength

Contingency Reserve Evaluation for Fast Frequency Response of Multiple Battery Energy Storage Systems in a Large-scale Power Grid

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CSEE Journal of Power and Energy Systems 2023年第3期9卷 873-883页

作者： Indira Alcaide-Godinez Feifei Bai tapan Kumar Saha Rizah Memisevic School of Information Technology and Electrical Engineering the University of QueenslandBrisbaneQLD 4072Australia School of Information Technology and Electrical Engineering the University of Queensland(UQ)BrisbaneQLD 4072 School of Engineering and Built Environment Griffith UniversityGold CoastQLD 4222Australia EPEC Group BrisbaneQLD 4014Australia

Recently,the fast frequency response(FFR)service by large-scale battery energy storage systems(BESSs)has been successfully proved to arrest the frequency excursion during an unexpected power ***,adequate frequency response relies on proper evaluation of the contingency reserve of *** BESS FFR reserve is commonly managed under fixed contracts,ignoring various response characteristics of different BESSs and their coexisting *** paper proposes a new methodology based on dynamic grid response and various BESS response characteristics to optimise the FFR reserves and prevent the frequency from breaching the under-frequency load shedding(UFLS)*** superiority of the proposed method is demonstrated to manage three large-scale BESSs operating simultaneously in an Australian power grid under high renewable penetration ***,the proposed method can identify remaining battery power and energy reserve to be safely utilised for other grid services(e.g.,energy arbitrage).The results can provide valuable insights for integrating FFR into conventional ancillary services and techno-effective management of multiple BESSs.

关键词： Fast frequency response(FFR) fast frequency contingency reserve multiple large-scale battery energy storage system(BESS) synthetic inertia requirement under-frequency load shedding(UFLS)

Organic farming in India: a vision towards a healthy nation

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Food Quality and Safety 2020年第2期4卷 69-76页

作者： Suryatapa Das Annalakshmi Chatterjee tapan Kumar Pal Department of Food and Nutrition Maharani Kasiswari CollegeUniversity of CalcuttaKolkataIndia Department of Home Science University of CalcuttaKolkataIndia Department of Biotechnology Bengal Institute of TechnologyKolkataIndia

Food quality and safety are the two important factors that have gained ever-increasing attention in general *** grown foods have immense adverse health effects due to the presence of higher pesticide residue,more nitrate,heavy metals,hormones,antibiotic residue,and also genetically modified ***,conventionally grown foods are less nutritious and contain lesser amounts of protective *** the quest for safer food,the demand for organically grown foods has increased during the last decades due to their probable health benefits and food safety *** food production is defined as cultivation without the application of chemical fertilizers and synthetic pesticides or genetically modified organisms,growth hormones,and *** popularity of organically grown foods is increasing day by day owing to their nutritional and health *** farming also protects the environment and has a greater socio-economic impact on a *** is a country that is bestowed with indigenous skills and potentiality for growth in organic *** India was far behind in the adoption of organic farming due to several reasons,presently it has achieved rapid growth in organic agriculture and now becomes one of the largest organic producers in the ***,organic farming has a great impact on the health of a nation like India by ensuring sustainable development.

关键词： food safety organic food biodiversity sustainable farming conventional farming

Evidence of the oldest extant vascular plant(horsetails)from the Indian Cenozoic

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植物多样性:英文版 2023年第5期45卷 569-589页

作者： Sampa Kundu Taposhi Hazra tapan chakraborty Subir Bera Mahasin Ali Khan Palaeobotany and Palynology Laboratory Department of BotanySidho-Kanho-Birsha UniversityRanchi RoadPurulia 723104India Geological Studies Unit Indian Statistical Institute203B.T.RoadKolkata 700108West BengalIndia Centre of Advanced Study Department of BotanyUniversity of Calcutta35B.C.RoadKolkata 700019India

Equisetum(Equisetaceae)has long been a focus of attention for botanists and palaeontologists because,given its extensive and well-documented fossil record,it is considered the oldest extant vascular plant and a key element in understanding vascular plant ***,to date,no authentic fossil evidence of Equisetum has been found from the Indian ***,we describe a new fossil species,namely,*** ***.,recovered from the middle Siwalik(Late Miocene)sediments of Himachal Pradesh,western *** identified fossil specimens based on morphological and epidermal *** addition,X-Ray diffraction(XRD)analysis was used to determine the mineral composition of compressed stems of *** close affinity of our recovered Siwalik fossils to Equisetum is supported by the presence of both macromorphological and epidermal *** Equisetum generally grows in wet conditions around water reservoirs,our findings indicate that the fossil locality was humid and surrounded by swamp and lowland regions during *** fossil evidence indicates that this sphenopsid once existed in the western Himalaya during the Siwalik ***,at present Equisetum is confined to a particular area of our fossil locality,probably a consequence of severe environmental changes coupled with competition from opportunistic *** discovery of Equisetum fossils in appreciable numbers from the Siwalik sediments of the Himachal Himalayas is unique and constitutes the first reliable recognition of Equisetum from the Indian Cenozoic.

关键词： Equisetum Fossil stem and leaf sheaths Late Miocene Paleoecology Siwalik Western India