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Kinetic studies on the reduction of iron ore nuggets by devolatilization of lean-grade coal

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International Journal of Minerals,Metallurgy and Materials 2016年第12期23卷 1360-1368页

作者： Chanchal Biswas Prithviraj Gupta Arnab De Mahua Ghosh Chaudhuri rajib dey Department Metallurgical and Material Engineering Jadavpur University Department of Metallurgy and Materials Engineering Indian Institute of EngineeringScience & Technology School of Materials Science and Nano Technology Jadavpur University

An isothermal kinetic study of a novel technique for reducing agglomerated iron ore by volatiles released by pyrolysis of lean-grade non-coking coal was carried out at temperature from 1050 to 1200℃ for 10-120 min. The reduced samples were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and chemical analysis. A good degree of metallization and reduction was achieved. Gas diffusion through the solid was identified as the reaction-rate-controlling resistance; however, during the initial period, particularly at lower temperatures, resistance to interfacial chemical reaction was also significant, though not dominant. The apparent rate constant was observed to increase marginally with decreasing size of the particles constituting the nuggets. The apparent activation energy of reduction was estimated to be in the range from 49.640 to 51.220 kJ/mol and was not observed to be affected by the particle size. The sulfur and carbon contents in the reduced samples were also determined.

关键词： iron ore reduction coal devolatilization kinetic studies

Microbial leaching of chromite overburden from Sukinda mines,Orissa,India using Aspergillus niger

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International Journal of Minerals,Metallurgy and Materials 2013年第8期20卷 705-712页

作者： Supratim Biswas Saikat Samanta rajib dey Siddhartha Mukherjee Pataki C.Banerjee Department of Metallurgical and Material Engineering Jadavpur UniversityKolkata-700032India School of Materials Science and Nanotechnology Jadavpur UniversityKolkata-700032India

Leaching of nickel and cobalt from two physical grades （S1, 125-190 μm, coarser and S3, 53-75 μm, finer） of chromite overburden was achieved by treating the overburden （2% pulp density） with 21-d culture filtrate of an Aspergillus niger strain grown in sucrose medium. Metal dissolution increases with ore roasting at 600℃ and decreasing particle size due to the alteration of microstructural properties involving the conversion of goethite to hematite and the increase in surface area and porosity as evident from X-ray diffraction （XRD）, thermogravimetry-differential thermal analysis （DT- TGA）, and field emission scanning electron microscopy （FESEM）. About 65% Ni and 59% Co were recovered from the roasted S3 ore employing bioleaching against 26.87% Ni and 31.3% Co using an equivalent amount of synthetic oxalic acid under identical conditions. The results suggest that other fungal metabolites in the culture filtrate played a positive role in the bioleaching process, making it an efficient green approach in Ni and Co recovery from lateritic chromite overburden.

关键词： nickeliferous laterite bioleaching Aspergillus niger chromite nickel metallurgy cobalt metallurgy

Mineralogy and carbothermal reduction behaviour of vanadium-bearing titaniferous magnetite ore in Eastern India

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International Journal of Minerals,Metallurgy and Materials 2013年第10期20卷 917-924页

作者： Saikat Samanta Manik Chandra Goswami Tapan Kumar Baidya Siddhartha Mukherjee rajib dey Department Metallurgical and Material Engineering Jadavpur University National Metallurgical Laboratory Department of Geological Sciences Jadavpur University

Vanadium-beaxing titaniferous magnetite bands hosted by Precambrian gabbro-norite-anorthositic rocks or their metamorphic equivalents were discovered in some parts of Eastern Indian Shield, containing 48%-49% Fe （total）, 10%-25% TiO2, and 0.3%-2.20% V2O5 by mass. Mineralogical and petrological study, composition, and characterization of the vanadium-bearing titaniferous magnetite ore were carried out by scanning electron microscopy-energy dispersive X-ray （SEM-EDX）, wave length X-ray florescence （WDXRF）, inductively coupled plasma-atomic emission spectroscopy （ICP-AES）, X-ray diffraction （XRD）, etc. Chemical beneficiation for valuable metals, such as Fe, Ti, andV, was performed by reduction roasting. The direct and indirect reduction were investigated by mixing the lump ore with solid activated charcoal in a closed reactor and purging the reducing gas mixture in standard reducibility index apparatus at different temperatures and time intervals. The reduction roasting parameters were optimized. Finally, the reduced samples were crushed and upgraded by magnetic separation. The results show that, the maximum mass fractions of magnetic and nonmagnetic parts achieved axe 69.36% and 30.64%, respectively, which contain 10.6% TiO2 and 0.84% V205 in the magnetic part and 36.5% TiO2 and 0.22% V205 in the nonmagnetic part.

关键词： magnetite mineralogy carbothermal reduction beneficiation vanadium

Workout Action Recognition in Video Streams Using an Attention Driven Residual DC-GRU Network

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Computers, Materials & Continua 2024年第5期79卷 3067-3087页

作者： Arnab dey Samit Biswas Dac-Nhuong Le Department of Computer Science and Technology Indian Institute of Engineering Science and TechnologyShibpurHowrah711103India Faculty of Information Technology Haiphong UniversityHaiphong180000Vietnam

Regular exercise is a crucial aspect of daily life, as it enables individuals to stay physically active, lowers thelikelihood of developing illnesses, and enhances life expectancy. The recognition of workout actions in videostreams holds significant importance in computer vision research, as it aims to enhance exercise adherence, enableinstant recognition, advance fitness tracking technologies, and optimize fitness routines. However, existing actiondatasets often lack diversity and specificity for workout actions, hindering the development of accurate recognitionmodels. To address this gap, the Workout Action Video dataset (WAVd) has been introduced as a significantcontribution. WAVd comprises a diverse collection of labeled workout action videos, meticulously curated toencompass various exercises performed by numerous individuals in different settings. This research proposes aninnovative framework based on the Attention driven Residual Deep Convolutional-Gated Recurrent Unit (ResDCGRU)network for workout action recognition in video streams. Unlike image-based action recognition, videoscontain spatio-temporal information, making the task more complex and challenging. While substantial progresshas been made in this area, challenges persist in detecting subtle and complex actions, handling occlusions,and managing the computational demands of deep learning approaches. The proposed ResDC-GRU Attentionmodel demonstrated exceptional classification performance with 95.81% accuracy in classifying workout actionvideos and also outperformed various state-of-the-art models. The method also yielded 81.6%, 97.2%, 95.6%, and93.2% accuracy on established benchmark datasets, namely HMDB51, Youtube Actions, UCF50, and UCF101,respectively, showcasing its superiority and robustness in action recognition. The findings suggest practicalimplications in real-world scenarios where precise video action recognition is paramount, addressing the persistingchallenges in the field. TheWAVd datas

关键词： Workout action recognition video stream action recognition residual network GRU attention

Analysis of Progressively Type-Ⅱ Inverted Generalized Gamma Censored Data and Its Engineering Application

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Computer Modeling in Engineering & Sciences 2024年第10期141卷 459-489页

作者： Refah Alotaibi Sanku dey Ahmed Elshahhat Department of Mathematical Sciences College of SciencePrincess Nourah bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia Department of Statistics St.Anthony’s CollegeShillong793001India Faculty of Technology and Development Zagazig UniversityZagazig44519Egypt

A novel inverted generalized gamma(IGG)distribution,proposed for data modelling with an upside-down bathtub hazard rate,is *** many real-world practical situations,when a researcher wants to conduct a comparative study of the life testing of items based on cost and duration of testing,censoring strategies are frequently *** this point of view,in the presence of censored data compiled from the most well-known progressively Type-Ⅱ censoring technique,this study examines different parameters of the IGG *** a classical point of view,the likelihood and product of spacing estimation methods are *** Fisher information and the deltamethod are used to obtain the approximate confidence intervals for any unknown parametric function of the *** the Bayesian paradigm,the same traditional inferential approaches are used to estimate all unknown ***-Chain with Monte-Carlo steps are considered to approximate all Bayes’*** numerical comparisons are presented to examine the performance of the proposed methodologies using various criteria of ***,using several optimality criteria,the optimumprogressive censoring design is *** highlight how the proposed estimators can be used in practice and to verify the flexibility of the proposed model,we analyze the failure times of twenty mechanical components of a diesel engine.

关键词： Inverted generalized gamma censoring spacing function likelihood Bayesian optimal plan

How Does the Blue C Stock Vary in Restored and Degraded Wetlands Across Land Cover Mosaics? Evidences from Medinipur Coastal Plain, India

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Journal of Resources and Ecology 2024年第4期15卷 898-908页

作者： Mansa dey Mrinmoyee NASKAR Sohini NEOGY Debajit DATTA Landscape Ecology Laboratory Department of GeographyJadavpur UniversityKolkata 700032India Department of Geography Baruipur CollegeBaruipur 743610India Department of Geography Banwarilal Bhalotia CollegeAsansol 713303India

Coastal wetlands are of paramount importance as major reservoirs of blue carbon(C),playing a crucial role in providing nature-based solutions to mitigate climatic *** research aimed to analyse the dynamics of total blue C(TBC)and its components;*** organic C(SOC),below ground C,and above ground C;as well how they are influenced by land use/land cover(LULC)categories and wetland ***,study were identified as one restored wetland and another degraded wetland in the Medinipur Coastal Plain,*** LULC categories were analyzed using Pleiades 1A and 1B satellite imagery,corresponding to the restored and degraded wetland,*** quantification of SOC was based on point-specific sample data collected from both wetlands(nr=250;nd=84).Above ground biomass(AGB)was appraised employing allometric relationships involving field-measured dendrometric *** ground biomass values were calculated using indirect allometric equations that take into account the AGB *** all the components,TBC stock of the restored and degraded wetlands were estimated at 246710.91 Mg and 7865.49 Mg,*** the restored wetland,dense mangrove and open mangrove exhibited higher concentrations of blue C components,while other LULC categories demonstrated moderate to low *** the degraded wetland,the open mangrove category rechigh densities of C pools,whereas herbaceous vegetation,bare earth and sand,and waterbody exhibited lower *** results portrayed significant disparities(P<0.05)in blue C pools among different LULC categories in both ***,it was evident that wetland type and LULC category had notable(P<0.001)impacts on TBC dynamics,both individually and in ***,this research may aid in effective management of coastal wetlands as blue C sinks,emphasizing their significance as essential elements of climate mitigation strategies.

关键词： blue C pools coastal wetland dendrometric variable landscape transformation mangrove plantation wetland restoration

A comprehensive review of 3D cancer models for drug screening and translational research

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Cancer Innovation 2024年第1期3卷 61-78页

作者： Karthikey Sharma Sreenath dey Rounik Karmakar Aravind Kumar Rengan Department of Biomedical Engineering Indian Institute of Technology(IIT)HyderabadIndia

The 3D cancer models fill the discovery gap of 2D cancer models and play an important role in cancer *** addition to cancer cells,a range of other factors include the stroma,density and composition of extracellular matrix,cancer-associated immune cells(e.g.,cancer-associated fibroblasts cancer cell-stroma interactions and subsequent interactions,and a number of other factors(e.g.,tumor vasculature and tumor-like microenvironment in vivo)has been widely ignored in the 2D concept of *** this knowledge,the continued use of monolayer cell culture methods has led to the failure of a series of clinical *** review discusses the immense importance of tumor microenvironment(TME)recapitulation in cancer research,prioritizing the individual roles of TME elements in cancer *** TME provided by the 3D model fulfills the requirements of in vivo spatiotemporal arrangement,components,and is helpful in analyzing various different aspects of drug sensitivity in preclinical and clinical trials,some of which are discussed ***,it discusses models for the co-assembly of different TME elements in vitro and focuses on their synergistic function and responsiveness as ***,this review broadly describes of a handful of recently developed 3D models whose main focus is limited to drug development and their screening and/or the impact of this approach in preclinical and translational research.

关键词： 3D models cancer drug development translational research tumor microenvironment elements

CuO–TiO_(2) based self-powered broad band photodetector

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Nano Materials Science 2024年第3期6卷 345-354页

作者： Chiranjib Ghosh Arka dey Iman Biswas Rajeev Kumar Gupta Vikram Singh Yadav Ashish Yadav Neha Yadav Hongyu Zheng Mohamed Henini Aniruddha Mondal Department of Physics National Institute of Technology DurgapurWest BengalIndia Department of Physics University of Petroleum&Energy Studies DehradunUttarakhandIndia Babasaheb Bhimrao Ambedkar University Lucknow226031India Center for Advanced Laser Manufacturing(CALM) Shandong University of TechnologyZibo255000PR China School of Physics and Astronomy University of NottinghamNottinghamNG72RDUnited Kingdom

An efficient room-temperature self-powered,broadband(300 nm–1100 nm)photodetector based on a CuO–TiO_(2)/TiO_(2)/p-Si(100)heterostructure is *** CuO–TiO_(2)nanocomposites were grown in a two-zone horizontal tube furnace on a 40 nm TiO_(2)thin film deposited on a p-type Si(100)*** CuO–TiO_(2)/TiO_(2)/p-Si(100)devices exhibited excellent rectification characteristics under dark and individual photoillumination *** devices showed remarkable photo-response under broadband(300–1100 nm)light illumination at zero bias voltage,indicating the achievement of highly sensitive self-powered photodetectors at visible and near-infrared light *** maximum response of the devices is observed at 300 nm for an illumination power of 10 *** response and recovery times were calculated as 86 ms and 78 ms,***,under a small bias,the devices showed a prompt binary response by altering the current from positive to negative under illumination *** main reason behind this binary response is the low turn-on voltage and photovoltaic characteristics of the *** illumination conditions,the generation of photocurrent is due to the separation of photogenerated electron-hole pairs within the built-in electric field at the CuO–TiO_(2)/TiO_(2)*** characteristics make the CuO–TiO_(2)/TiO_(2)broadband photodetectors suitable for applications that require high response speeds and self-sufficient functionality.

关键词： Self-powered CuO–TiO_(2) nanocomposite Broadband photodetector Two-zone horizontal tube furnace Responsivity

Importance of Stewards and Other Protection Efforts for Conservation of Red Knots (Calidris canutus rufa) and Other Shorebirds on Delaware Bay, New Jersey

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Natural Science 2024年第9期16卷 162-182页

作者： Joanna Burger Amanda dey Larry Niles Division of Life Sciences Rutgers University Piscataway NJ USA Wildlife Restoration Partnerships 109 Market Lane Greenwich NJ USA

Understanding the factors that contribute to population stability in long-distance migrant birds is increasingly important, particularly given global climate change, sea level rise, and loss or disturbance at essential habitats. While the populations of most shorebirds are declining worldwide, those that migrate through Delaware Bay, New Jersey and Delaware, are declining at the most rapid rate despite conservation efforts. In this paper, we 1) provide background information on population declines of red knots (Calidris canutus rufa) using Delaware Bay, threats to their foraging, and efforts to reduce threats, 2) summarize briefly our studies of the effects of human activities on knots and other shorebirds, 3) present data on management efforts to protect knots and other shorebirds from the activities of people, and 4) discuss the efficacy of such efforts (usually referred to as “decreasing the effect of human disturbances”). The Shorebird Project on Delaware Bay is over 25 years old and provides long-term data to help assess the status of shorebird numbers, particularly for red knot, as well as the density of horseshoe crabs (Limulus polyphemus) and their eggs. Red knots have continued to decline even more precipitously in the last few years, presenting cause for concern. Protective efforts have been successful in reducing human disruption on the N.J. Delaware Bay beaches, but the lack of uniformity in implementation across the New Jersey side, and across the whole Bay have hampered further improvements. Implementation of signs, fencing, and stewards on some beaches significantly enhanced the use of these beaches by red knots, determined by examining the use of beaches pre- and post-implementation. Implementation of fencing and stewards had the greatest effect. From 1986 to 2018, there was a significant shift in the percent of Delaware Bay red knots using the NJ side, where protection efforts had been implemented on many of the beaches. Merely restricting access (w

关键词： Red Knot Calidris canutus rufa Conservation Beach Monitors Human Disturbance Habitat Restoration Management Stewards Education Population Declines Coastal