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TGA/DSC study to characterise and classify coal seams conforming to susceptibility towards spontaneous combustion

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International Journal of Mining Science and Technology 2022年第1期32卷 75-88页

作者： Niroj Kumar Mohalik Somu Mandal Santosh Kumar Ray Asfar Mobin Khan debashish Mishra Jai Krishna Pandey CSIR-Central Institute of Mining and Fuel Research(CIMFR) Dhanbad 826015India Academy of Scientific and Innovative Research(AcSIR) Ghaziabad 201002India

Thermogravimetric analysis/differential scanning calorimeter(TGA/DSC)technique along with basic coal characteristics study is carried out for eighty coal samples of Indian coalfields,to determine spontaneous combustion propensity behaviour of *** study of coal samples indicates that there is an increase in the mass of coal samples in the temperature range 150-350℃,which may be due to oxygen adsorption and *** correlation and principal component analysis states that the component of proximate analysis(M_(ad),VM_(d),FR,and VR)have an acceptable correlation with the TGA experiments results i.e.,Tgsh and *** fixed nonlinear regression analysis shows that thermogravimetry(TG)experiment results Tgign may be the best index to categorise/classify the coal as per their susceptibility towards spontaneous *** authors proposed four groups of classification as per their propensity towards spontaneous combustion depending upon the moisture(M_(ad)),volatile matter(VM_(d)),and TG ignition temperature from differential thermogravimetric(DTG)curve(Tgign)using hierarchal clustering *** coal samples of different seams from Indian coalfield may be classified into four different clusters,*** highly/extremely susceptible(Tgign320℃).The field observations and TGA/DSC experiment results with the following statistical analysis substantiate a similar assessment.

关键词： Coal TGA/DSC Spontaneous combustion TG ignition

Geochemical, mineralogical and textural nature of beach placers,north-east Sri Lanka: Implications for provenance and potential resource

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International Journal of Sediment Research 2023年第2期38卷 279-293页

作者： Samikshya Mohanty Madurya Adikaram debashish Sengupta Nishara Madhubashini Chelaka Wijesiri Somnath Adak Biswajit Bera Indian Institute of Technology (IIT) Department of Physical Sciences South Eastern University of Sri Lanka 3. Uva Wellassa University 4. Sidho-Kanho-Birsa University

The Pulmoddai placer sands in Sri Lanka(9°3’23.65’’-8°51’38.83’’N and 80°55’22.91’’-81°3’32.65’’E) is considered to be one of the major rare earth element(REE) prospects world-wide. This deposit has a global significance in terms of strategic economic resources and can provide valuable insight for resource estimation and for its economic use. A detailed study of the geochemical, mineralogical, and textural properties of the heavy minerals of this region is undertaken applying the scanning electron microscopy-electron dispersive X-ray spectroscopy(SEM-EDS), inductively coupled plasma-optical emission spectroscopy(ICP-OES), X-Ray diffraction(XRD), and X-Ray fluorescence(XRF) techniques. The results from these analyses are modeled to delineate the source(s) which contribute to the formation of the mineral deposits and their subsequent enrichment. The beach sediment from this region, exhibited elevated concentrations of major elements like silicon(Si) and manganese(Mn) and high abundance of minor and trace elements like yttrium(Y), strontium(Sr), lanthanum(La), barium(Ba), which indicates that the provenance is similar to calcium-silicate rocks. The highest(total) concentration of Y, La, scandium(Sc) and cerium(Ce) are mainly associated to fine grained sediment, signifying that their occurrences are governed by the grain size distribution and ambient hydrodynamic conditions primarily from lagoonal input. Monazite, zircon, ilmenite, rutile, and xenotime are more abundant than garnet in the study area, as is evident from the higher abundance of thorium(Th) and uranium(U) and the enrichment of zirconium(Zr), Ce, vanadium(V), chromium(Cr), and Y. Textural analysis of sediment shows sediment particles are poorly sorted and have more angular grain boundaries, indicating their lower textural maturity. This suggests that the sediment is fluvially derived from a close source rock of charnockite specific to the hinterland lithology. The sediment transported by perennial rivers an

关键词： Rare earth elements Kokkilai lagoon Geochemistry Monazite Beach placer deposit

Review of preventive and constructive measures for coal mine explosions:An Indian perspective

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International Journal of Mining Science and Technology 2022年第3期32卷 471-485页

作者： Santosh Kumar Ray Asfar Mobin Khan Niroj Kumar Mohalik debashish Mishra Somu Mandal Jai Krishna Pandey CSIR-Central Institute of Mining and Fuel Research Barwa RoadDhanbad 826015India Academy of Scientific and Innovative Research(AcSIR) Ghaziabad 201002India

Firedamp and coal dust explosion constitute a lion’s share in mine accidents in a global mining *** paper reports a list of mine explosion disasters since last two decades,a critical review of the different prevention and constructive measures,and its recent development to avoid firedamp and coal dust *** legislation in core coal-producing countries,***,USA,Australia,South Africa,and India related to firedamp and coal dust explosion are critically *** occurred due to explosion after Nationalisation of Coal Mines(1973)in India are *** and constructive measures adopted in India are critically analysed with respect to the global mining *** like methane credit concept,classification of mines/seams with respect to explosion risk zone,deflagration index;installation of automatic fire warning devices,canopy air curtain technology,explosion-prevention measures,such as fire-retardant materials,inhibitors,extinguishing agent,dust suppressor,and active explosion barrier are discussed in detail to avoid explosion and thereby adhering to zero accident policy due to coal mine explosion.

关键词： Firedamp explosion Coal dust explosion Preventive measures Constructive measures Legislation

Numerical analysis of rainfall effects in external overburden dump

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International Journal of Mining Science and Technology 2016年第5期26卷 825-831页

作者： Radhakanta Koner debashish Chakravarty Department of Mining Engineering Indian Institute of Technology

The effect of slope angle for external overburden dump in response to average and heavy rainfall has been analyzed using a two dimensional finite difference method of transient water flow through unsaturated–saturated soil. The external dump stability is evaluated for five geomaterial types on the basis of globally accepted safety factor analysis technique, based on shear strength reduction approach using finite difference method. The results obtained from the finite difference method of analysis indicate that the external dump with more than 30° slope angle is greatly influenced by the rainfall under the studied conditions for geomaterial 3, 4 and 5, whereas dumps with geomaterial 1 and 2 remain safe. The analysis shows that major slope failure is out of preview for the studied rainfall conditions.

关键词： External overburden dumps Shear strength reduction Finite difference approach Rainfall Stability

Improvement of Early Maturing and Climate Resilient Chickpea (Cicer arietinum L.) Cultivars Suitable for Multiple Environments in Bangladesh

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Phyton-International Journal of Experimental Botany 2023年第3期92卷 883-899页

作者： Aktar-Uz-Zaman Ariful Islam Shahin Iqbal Jahangir Alam debashish Sarkar Bander Albogami Ahmed Gaber Akbar Hossain Pulses Research Centre Bangladesh Agricultural Research InstituteIshurdiPabna6600Bangladesh On-Farm Research Division Bangladesh Agricultural Research InstitutePabna6600Bangladesh Department of Biology College of ScienceTaif UniversityTaif21944Saudi Arabia Division of Soil Science Bangladesh Wheat and Maize Research InstituteDinajpur5200Bangladesh

Ensuring food security for the rapidly increasing population and changing climatic scenarios are requisites for exploiting the genetic divergence of food crops.A study was undertaken to sort out an early maturing chickpea variety for fitting easily between rice-rice cropping systems in the Eastern Indo-Gangetic Plain of *** trial was comprised of eight elite lines of chickpea and executed at various localities in Bangladesh from 2014–15 to 2017–*** result explored the chickpea genotype,BARI Chola-11 remained superior to the rest of the elite genotypes for having a short maturity period(100–106 days),and lesser days to 50%flowering(47–55 days).The same genotype was recorded to have robust vegetative and reproductive yield attributes including plant height(49–57 cm),podsplant−1(37–50),and optimum 100 seed weight(19.5–20.6 g).Owing to better yield attributes,BARI Chola-11 resulted in the maximum seed yield(1200–1500 kg ha-1)of chickpea and might be recommended for general adoption in the region for boosting nutritional security status through improved productivity under changing climate.

关键词： Short-duration variety multi-location yield trial high yielding variety GGE biplot analysis preliminary yield trial super early type

Development of a mass model in estimating weight-wise particle size distribution using digital image processing

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International Journal of Mining Science and Technology 2017年第3期27卷 435-443页

作者： Maiti Abhik Chakravarty debashish Biswas Kousik Halder Arpan Department of Mining Engineering Indian Institute of Technology Kharag-pur 721302 India

Particle size distribution of coarse aggregates through mechanical sieving gives results in terms of cumulative mass percent. But digital image processing generated size distribution of particles, while being fast and accurate, is often expressed in terms of area function or number of particles. In this paper, a mass model is developed which converts the image obtained size distribution to mass-wise distribution, making it readily comparable to mechanical sieving data. The concept of weight/particle ratio is introduced for mass reconstruction from 2D images of particle aggregates. Using this mass model, the effects of several particle shape parameters(such as major axis, minor axis, and equivalent diameter) on sieve-size of the particles is studied. It is shown that the sieve-size of a particle strongly depend upon the shape parameters, 91% of its variation being explained by major axis, minor axis, bounding box length and equivalent diameter. Furthermore, minor axis gives an overall accurate estimate of particle sieve-size, error in mean size(D-50) being just 0.4%. However, sieve-size of smaller particles(20 mm) are highly correlated to their equivalent diameters. Multiple linear regression analysis has been used to generate overall mass-wise particle size distribution, considering the influences of all these shape parameters on particle sieve-size. Multiple linear regression generated overall mass-wise particle size distribution shows a strong correlation with sieve generated data. The adjusted R-square value of the regression analysis is found to be 99 percent(w.r.t cumulative frequency). The method proposed in this paper provides a time-efficient way of producing accurate(up to 99%) mass-wise PSD using digital image processing and it can be used effectively to replace the mechanical sieving.

关键词：数字图像处理法颗粒分布质量模型重量估计回归分析方法多元线性回归粒子尺寸

Discrete element approach for mine dump stability analysis

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矿业科学技术：英文版 2010年第6期20卷 809-813页

作者： RADHAKANTA Koner debashish Chakravarty Department of Mining Engineering Indian Institute of Technology

Mine overburden dumps have posed significant safety issues in the operations of various unit operations of open pit min-ing especially the external dumps. The external dumps are composed of a mixture of fragmented rocks and loose soil. Their charac-teristic is comparable to heavily discontinuous solid mass. The conventional approach of limit equilibrium methods provide safety factors for the slope but nothing about the stress-strain characteristics of the large dump mass. The designs of dump location and their respective geometry are integrated for the know-how of the stability characteristics of these dumps. The discrete element method uses a circular disk to represent the granular solid mass and their interactions are described by the Newton’s third law of motion. The displacement is described by the sliding of the circular disk. This work is focused on the modeling efficiency of the discrete element methods to represent the behaviour of mine dump masses with the specified joint plane for the limit equilibrium method. The advantage of the work lies on the ease of information retrieval at any point at the dump mass concerning the stress and strain histories, displacement, failures etc. which when integrated produces a better understanding of the stability of the dump masses.

关键词：矿山排土场稳定性离散元法应力应变特性露天矿排土场极限平衡法离散元方法安全问题

Carbon nanotubes:Evaluation of toxicity at biointerfaces

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Journal of Pharmaceutical Analysis 2019年第5期9卷 293-300页

作者： debashish Mohanta Soma Patnaik Sanchit Sood Nilanjan Das Department of Biotechnology Manav Rachna International Institute of Research Studies Faridabad Haryana India Accendere KMS New Delhi India

Carbon nanotubes (CNTs) are a class of carbon allotropes with interesting properties that make them productive materials for usage in various disciplines of nanotechnology such as in electronics equipments, optics and therapeutics. They exhibit distinguished properties viz., strength, and high electrical and heat conductivity. Their uniqueness can be attributed due to the bonding pattern present between the atoms which are very strong and also exhibit high extreme aspect ratios. CNTs are classified as singlewalled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) on the basis of number of sidewalls present and the way they are arranged spatially. Application of CNTs to improve the performance of many products, especially in healthcare, has led to an occupational and public exposure to these nanomaterials. Hence, it becomes a major concern to analyze the issues pertaining to the toxicity of CNTs and find the best suitable ways to counter those challenges. This review summarizes the toxicity issues of CNTs in vitro and in vivo in different organ systems (bio interphases) of the body that result in cellular toxicity.

关键词： Bio interphases Carbon nanotubes (CNTs) In vivo toxicity In vitro toxicity

Structural, electronic, and mechanical properties of cubic TiO_2:A first-principles study

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Chinese Physics B 2018年第1期27卷 492-500页

作者： debashish Dash Chandan K Pandey Saurabh Chaudhury Susanta K Tripathy Department of Electrical Engineering National Institute of TechnologySilchar Assam Department of Electronics and Communication Engineering National Institute of TechnologySilchar Assam

We present an analysis of structural, electronic, and mechanical properties of cubic titanium dioxide （TiO2） using an all electron orthogonalzed linear combinations of atomic orbitals （OLCAO） basis set under the framework of density functional theory （DFT）. The structural property, especially the lattice constant a, and the electronic properties such as the band diagram and density of states （DOS） are studied and analyzed. The mechanical properties such as bulk moduli, shear moduli, Young＇s Moduli, and Poison＇s ratio are also investigated thoroughly. The calculations are carried out on shear moduli and anisotropy factor for cubic TiO2. The Vickers hardness is also tested for fluorite and pyrite cubic-structured TiO2. Furthermore, the results are compared with the previous theoretical and experimental results. It is found that DFT- based simulation produces results which are approximation to experimental results, whereas the calculated elastic constants are better than the previous theoretical and experimental values.

关键词： density functional theory cubic TiO2 structural electronic and mechanical properties