检索结果-南通市图书馆

Geochemical signatures of potassium metasomatism in anthracite from the Himalayan fold‑thrust belts of Sikkim,India

International Journal of Coal Science & Technology 2022年第2期9卷 48-69页

作者： Santanu Ghosh Anwita Ojha atul kumar Varma Coal Geology and Organic Petrology Laboratory Department of Applied GeologyIndian Institute of Technology(Indian School of Mines)DhanbadJharkhand 826004India Department of Earth Sciences Indian Institute of Technology BombayPowaiMumbaiMaharashtra 400076India

The present study focuses on the inorganic geochemical features of the bituminous coal samples from the Raniganj and the Jharia Basins,as well as the anthracite samples from the Himalayan fold-thrust belts of Sikkim,India.The SiO_(2)content(48.05 wt%to 65.09 wt%and 35.92 wt%to 50.11 wt%in the bituminous and anthracite samples,respectively)and the ratio of Al_(2)O_(3)/TiO_(2)(6.97 to 17.03 in the bituminous coal samples and 10.34 to 20.07 in the anthracite samples)reveal the intermediate igneous source rock composition of the minerals.The ratio of the K_(2)O/Al_(2)O_(3)in the ash yield of the bituminous coal samples(0.03 to 0.09)may suggest the presence of kaolinite mixed with montmorillonite,while its range in the ash yield of the anthracite samples(0.16 to 0.27)may imply the presence of illite mixed with kaolinite.The chemical index of alteration values may suggest the moderate to strong chemical weathering of the source rock under sub-humid to humid climatic conditions.The plot of the bituminous coal samples in the A–CN–K diagram depicts the traditional weathering trend of parent rocks,but the anthracite samples plot near the illite feld and are a bit ofset from the weathering trend.This may imply the plausible infuences of the potassium-metasomatism at post coalifcation stages,which is further supported by high K_(2)O/Na_(2)O ratio(29.88–80.13).The Fourier transform infrared spectra further reveal the hydroxyl stretching intensity of illite in the anthracite samples substantiating the efect of the epigenetic potassium-metasomatism.The decrease in total kaolinite intensity/compound intensity of quartz and feldspar may provide additional evidence towards this epigenetic event.

关键词： Himalayan fold-thrust belts Anthracite Potassium metasomatism Kaolinite to quartz-feldspar intensity ratio Montmorillonite stretching and bending intensities Illite-stretching frequency

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Spectral narratives of microstructural restyling and their controls on hydrocarbon generation potential from coal

引用

International Journal of Coal Science & Technology 2023年第3期10卷 167-189页

作者： Tushar Adsul Santanu Ghosh Anwita Ojha Sudip Bhattacharyya atul kumar Varma Coal Geology and Organic Petrology Laboratory Department of Applied GeologyIndian Institute of Technology(Indian School of Mines)DhanbadJharkhand 826004India Department of Geology Mizoram UniversityAizawlMizoram 796004India Specialized Coal Petrography Laboratory Natural Energy ResourcesMission II-BGeological Survey of IndiaDK-6Sector-IlSalt Lake CityKolkataWest Bengal 700091India

The low to medium-rank Tertiary coals from Meghalaya,India,are explored for the first time for their comprehensive micro-structural characterization using the FTIR and Raman spectroscopy.Further,results from these coals are compared with the Permian medium and high-rank coals to understand the microstructural restyling during coalification and its controls on hydrocarbon generation.The coal samples are grouped based on the mean random vitrinite reflectance values to record the transformations in spectral attributes with increasing coal rank.The aliphatic carbon and the apparent aromaticity respond sharply to the first coalification jump(R:0.50%)during low to medium-rank transition and anchizonal metamorphism of the high-rank coals.Moreover,the Raman band intensity ratio changes during the first coalification jump but remains invari-able in the medium-rank coals and turns subtle again during the onset of pregraphitization in high-rank coals,revealing a polynomial trend with the coal metamorphism.The Rock-Eval hydrogen index and genetic potential also decline sharply at the first coalification jump.Besides,an attempt to comprehend the coal microstructural controls on the hydrocarbon poten-tial reveals that the Tertiary coals comprise highly reactive aliphatic functionalities in the type I-S kerogen,along with the low paleotemperature(74.59-112.28℃)may signify their potential to generate early-mature hydrocarbons.However,the presence of type II-II admixed kerogen,a lesser abundance of reactive moieties,and overall moderate paleotemperature(91.93-142.52℃)of the Permian medium-rank coals may imply their mixed hydrocarbon potential.Meanwhile,anchizonal metamorphism,polycondensed aromatic microstructure,and high values of paleotemperature(~334.25 to~366.79℃)of the high-rank coals indicate a negligible potential of producing any hydrocarbons.

关键词： Early mature oil generation Meghalaya high-sulfur coal Type II-S kerogen Microstructural ordering Coalification jump Hydrocarbon generation potential

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Organo-Petrographic and Pore Facets of Permian Shale Beds of Jharia Basin with Implications to Shale Gas Reservoir

引用

Journal of Earth Science 2017年第5期28卷 897-916页

作者： Vinod Atmaram Mendhe Subhashree Mishra Ranjit G.Khangar Alka Damodhar Kamble Durgesh kumar atul kumar Varma H.Singh Sujeet kumar Mollika Bannerjee CSIR-Central Institute of Mining and Fuel Research GSI-Geological Survey of India Central Region IIT (ISM)-Department of Chemical Engineering Indian Institute of Technology (ISM) IIT (ISM)-Department of Applied Geology Indian Institute of Technology (ISM)

The shale deposits of Damodar Valley have received great attention since preliminary studies indicate their potential for shale gas. However, fundamental information allied to shale gas re- servoir characteristics are still rare in India, as exploration is in the primary stage. In this study, Ba- rakar shale beds of eastern part of Jharia Basin are evaluated for gas reservoir characteristics. It is evident that Barakar shales are carbonaceous, silty, contains sub-angular flecks of quartz and mica, irregular hair-line fractures and showing lithological variations along the bedding planes, signifying terrestrial-fluviatile deposits under reducing environment. The values of TOC varies from 1.21 wt.% to 17.32 wt.%, indicating good source rock potentiality. The vitrinite, liptinite, inertinite and mineral matter ranging from 0.28 vol.% to 12.98 vol.%, 0.17 vol.% to 3.23 vol.%, 0.23 vol.% to 9.05 vol.%, and 74.74 vol.% to 99.10 vol.%, respectively. The ternary facies plot of maceral composition substan- tiated that Barakar shales are vitrinite rich and placed in the thermal-dry gas prone region. The low values of the surface area determined following different methods point towards low methane storage capacity, this is because of diagenesis and alterations of potash feldspar responsible for pore blocking effect. The pore size distribution signifying the micro to mesoporous nature, while Type II sorption curve with the H2 type of hysteresis pattern, specifies the heterogeneity in pore structure mainly combined-slit and bottle neck pores.

关键词： shale gas petrographic composition surface area pore disposition pore volume.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Active Learning Query Strategies for Classification,Regression,and Clustering:A Survey

引用

Journal of Computer Science & Technology 2020年第4期35卷 913-945页

作者： Punit kumar atul Gupta Indian Institute of Information Technology Design and ManufacturingJabalpurMadhya Pradesh 482005India

Generally,data is available abundantly in unlabeled form,and its annotation requires some cost.The labeling,as well as learning cost,can be minimized by learning with the minimum labeled data instances.Active learning(AL),learns from a few labeled data instances with the additional facility of querying the labels of instances from an expert annotator or oracle.The active learner uses an instance selection strategy for selecting those critical query instances,which reduce the generalization error as fast as possible.This process results in a refined training dataset,which helps in minimizing the overall cost.The key to the success of AL is query strategies that select the candidate query instances and help the learner in learning a valid hypothesis.This survey reviews AL query strategies for classification,regression,and clustering under the pool-based AL scenario.The query strategies under classification are further divided into:informative-based,representative-based,informative-and representative-based,and others.Also,more advanced query strategies based on reinforcement learning and deep learning,along with query strategies under the realistic environment setting,are presented.After a rigorous mathematical analysis of AL strategies,this work presents a comparative analysis of these strategies.Finally,implementation guide,applications,and challenges of AL are discussed.

关键词： active learning active learning query strategy active classification active regression active clustering deep active learning

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

引用

Journal of Ocean Engineering and Science 2023年第2期8卷 111-123页

作者： Raj kumar Ravi Shankar Verma atul kumar Tiwari Department of Mathematics Faculty of Engineering&TechnologyVeer Bahadur Singh Purvanchal UniversityJaunpur222003India Department of Mathematics Motihari College of EngineeringMotihari845401BiharIndia

This work is devoted to get a new family of analytical solutions of the(2+1)-coupled dispersive long wave equations propagating in an infinitely long channel with constant depth,and can be observed in an open sea or in wide channels.The solutions are obtained by using the invariance property of the similarity transformations method via one-parameter Lie group theory.The repeated use of the similarity transformations method can transform the system of PDEs into system of ODEs.Under adequate restrictions,the reduced system of ODEs is solved.Numerical simulation is performed to describe the solutions in a physically meaningful way.The profiles of the solutions are simulated by taking an appropriate choice of functions and constants involved therein.In each animation,a frame for dominated behavior is captured.They exhibit elastic multisolitons,single soliton,doubly solitons,stationary,kink and parabolic nature.The results are significant since these have confirmed some of the established results of S.kumar et al.(2020)and K.Sharma et al.(2020).Some of their solutions can be deduced from the results derived in this work.Other results in the existing literature are different from those in this work.

关键词： Dispersive long wave equations Solitons Invariants Lie-group Similarity solutions

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

An approach for selection of solid waste treatment and disposal methods based on fuzzy analytical hierarchy process

引用

Waste Disposal and Sustainable Energy 2022年第4期4卷 311-322页

作者： Amarjeet kumar atul Sharma Nekram Rawal Department of Civil Engineering Motilal Nehru National Institute of Technology AllahabadAllahabad211004India

Solid waste management is a severe challenge in India due to massive and rapid growth in waste generation rates,environmental difficulties,and financial constraints for proper treatment.Poorly managed municipal solid waste(MSW)has substantial negative consequences for society,including financial and aesthetic harm,contamination of natural resources,environmental pollution,and severe health danger.Both qualitative and quantitative factors are required to select the appropriate solid waste treatment and disposal technologies.Multi-Criteria decision-making tools helped in analyzing solid waste in terms of qualitative and quantitative factors.In this paper,seven criteria and their sub-criteria are selected for ranking solid waste treatment and disposal technology using fuzzy-analytic hierarchy process.The results showed that composting is the most suitable option for solid waste treatment and disposal technology,followed by refuse-derived fuel.The incineration and sanitary landfills are the least preferred MSW management alternatives.The sensitivity analysis reveals a high consistency,robustness,and stability level.

关键词： Fuzzy-analytic hierarchy process Solid waste management Composting Refuse-derived fuel Incineration

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Recent advances in catalytic combustion of AP-based composite solid propellants

引用

Defence Technology（防务技术） 2021年第3期17卷 1013-1031页

作者： Narendra Yadav Prem kumar Srivastava Mohan varma Department of Space Engineering&Rocketry India Department of Chemistry Birla Institute of TechnologyMesraRanchiIndia

Composite solid propellants(CSPs) have widely been used as main energy source for propelling the rockets in both space and military applications. Internal ballistic parameters of rockets like characteristic exhaust velocity, specific impulse, thrust, burning rate etc., are measured to assess and control the performance of rocket motors. The burn rate of solid propellants has been considered as most vital parameter for design of solid rocket motors to meet specific mission requirements. The burning rate of solid propellants can be tailored by using different constituents, extent of oxidizer loading and its particle size and more commonly by incorporating suitable combustion catalysts. Various metal oxides(MOs),complexes, metal powders and metal alloys have shown positive catalytic behaviour during the combustion of CSPs. These are usually solid-state catalysts that play multiple roles in combustion of CSPs such as reduction in activation energy, enhancement of rate of reaction, modification of sequences in reaction-phase, influence on condensed-phase combustion and participation in combustion process in gas-phase reactions. The application of nanoscale catalysts in CSPs has increased considerably in recent past due to their superior catalytic properties as compared to their bulk-sized counterparts. A large surface-to-volume ratio and quantum size effect of nanocatalysts are considered to be plausible reasons for improving the combustion characteristics of propellants. Several efforts have been made to produce nanoscale combustion catalysts for advanced propellant formulations to improve their energetics. The work done so far is largely scattered. In this review, an effort has been made to introduce various combustion catalysts having at least a metallic entity. Recent developments of nanoscale combustion catalysts with their specific merits are discussed. The combustion chemistry of a typical CSP is briefly discussed for providing a better understanding on role of combustion catalysts in burning rate enhancement.

关键词： Composite solid propellants Burn rate modifier Metallic nano-catalysts Catalytic combustion Thermal decomposition

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nano/Micro-Structural Supramolecular Biopolymers: Innovative Networks with the Boundless Potential in Sustainable Agriculture

引用

NANO-MICRO LETTERS 2024年第1期16卷 1-23页

作者： Saberi Riseh, Roohallah Hassanisaadi, Mohadeseh Vatankhah, Masoumeh varma, Rajender S. Thakur, Vijay kumar Vali E Asr Univ Rafsanjan Fac Agr Dept Plant Protect Imam Khomeini Sq Rafsanjan *** Iran Univ Fed Sao Carlos Ctr Excellence Res Sustainable Chem Dept Chem BR-13565905 Sao Carlos SP Brazil Scotlands Rural Coll SRUC Biorefining & Adv Mat Res Ctr Edinburgh EH9 3JG Scotland

Safer and biodegradable nano/micro-supramolecular biopolymers transform farming practices.Supramolecular biopolymers improve soil structure, water retention, and plant nutrient uptake.Encapsulation of bioactive compounds and their controlled release by nano/micro-supramolecular biopolymers enables targeted delivery.Biopolymer networks can potentially be embedded in biosensors for crop protection goals. Sustainable agriculture plays a crucial role in meeting the growing global demand for food while minimizing adverse environmental impacts from the overuse of synthetic pesticides and conventional fertilizers. In this context, renewable biopolymers being more sustainable offer a viable solution to improve agricultural sustainability and production. Nano/micro-structural supramolecular biopolymers are among these innovative biopolymers that are much sought after for their unique features. These biomaterials have complex hierarchical structures, great stability, adjustable mechanical strength, stimuli-responsiveness, and self-healing attributes. Functional molecules may be added to their flexible structure, for enabling novel agricultural uses. This overview scrutinizes how nano/micro-structural supramolecular biopolymers may radically alter farming practices and solve lingering problems in agricultural sector namely improve agricultural production, soil health, and resource efficiency. Controlled bioactive ingredient released from biopolymers allows the tailored administration of agrochemicals, bioactive agents, and biostimulators as they enhance nutrient absorption, moisture retention, and root growth. Nano/micro-structural supramolecular biopolymers may protect crops by appending antimicrobials and biosensing entities while their eco-friendliness supports sustainable agriculture. Despite their potential, further studies are warranted to understand and optimize their usage in agricultural domain. This effort seeks to bridge the knowledge gap by investigating their applications, challenges, and future prospects in th

关键词： Supramolecular Biopolymers Sustainable agriculture Nanotechnology SOIL-WATER RETENTION POLYMERS HYDROGELS CELLULOSE CHITOSAN SUPERABSORBENT NANOMATERIALS BIOMATERIALS FABRICATION ACTUATORS

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Review on the phosphate-based conversion coatings of magnesium and its alloys

引用

International Journal of Minerals,Metallurgy and Materials 2022年第7期29卷 1435-1452页

作者： Debasis Saran atul kumar Sivaiah Bathula David Klaumünzer Kisor K Sahu School of Minerals Metallurgical and Materials EngineeringIndian Institute of Technology BhubaneswarBhubaneswar 752050India Group Innovation(COI Battery-Metals) Volkswagen AGWolfsburg 38440Germany Virtual and Augmented Reality Centre of Excellence(VARCOE) Indian Institute of Technology BhubaneswarBhubaneswar 752050India

Magnesium(Mg)and its alloys are lightweight as well as biocompatible and possess a high strength-to-weight ratio,making them suitable for many industries,including aerospace,automobile,and medical.The major challenge is their high susceptibility to corrosion,thereby limiting their usability.The considerably lower reduction potential of Mg compared to other metals makes it vulnerable to galvanic coupling.The oxide layer on Mg offers little corrosion resistance because of its high porosity,inhomogeneity,and fragility.Chemical conversion coatings(CCs)belong to a distinct class because of underlying chemical reactions,which are fundamentally different from other types of coating.Typically,a CC acts as an intermediate sandwich layer between the base metal and an aesthetic paint.Although chromate CCs offer superior performance compared to phosphate CCs,yet still they release carcinogenic hexavalent chromium ions(Cr^(6+));therefore,their use is prohibited in most European nations under the Registration,Evaluation,Authorization and Restriction of Chemicals legislation framework.Phosphate-based CCs are a cost-effective and environment-friendly alternative.Accordingly,this review primarily focuses on different types of phosphate-based CCs,such as zinc,calcium,Mg,vanadium,manganese,and permanganate.It discusses their mechanisms,current status,pretreatment practices,and the influence of various parameters-such as pH,temperature,immersion time,and bath composition-on the coating performance.Some challenges associated with phosphate CCs and future research directions are also elaborated.

关键词： phosphate conversion coatings magnesium alloys corrosion zinc phosphate conversion coatings calcium phosphate conversion coatings magnesium phosphate conversion coatings

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nitration of Jharia basin coals,India:a study of structural modifications by XRD and FTIR techniques

引用

International Journal of Coal Science & Technology 2021年第5期8卷 1034-1053页

作者： Prabal Boral atul K.varma Sudip Maity CSIR-Central Institute of Mining and Fuel Research PO:FRIDhanbad 828108India Department of Applied Geology Indian Institute of Technology(ISM)Dhanbad826004India

Four coal samples from Jharia basin,India are treated with nitric acid in glacial acetic acid and aqueous media to find out the chemical,petrographic and spatial structure of the organic mass by X-ray diffraction(XRD)and Fourier Transform Infrared Spectroscopy(FTIR)techniques.X-ray parameters of coal like interlayer spacing(d_(002)),crystallite size(L_(c)),aroamticity(f_(a)),average number of aromatic layers(N_(c)),and coal rank(I_(26)/I_(20))have been determined using profilefitting software.Considerable variation is observed in treated coals in comparison to the demineralized coals.The d_(002)values of treated coals have increased in both the media showing increase in disordering of organic moieties.A linear relationship has been observed between d_(002)values with the volatile matter of the coals.Similarly,the d_(002)values show linear relationship with C_(dmf) contents for demineralized as well as for the treated coals in both the media.The L_(c) and N_(c) values have decreased in treated coals corresponding to demineralized coals.The present study shows that nitration in both the media is capable of removing the aliphatic side chains from the coals and aromaticity(f_(a))increases with increase in rank and shows a linear relationship with the vitrinite reflectance.The corresponding I_(26)/I_(20)values are least for treated coals in glacial acetic acid medium followed by raw and then to treated coals in aqueous medium.FTIR studies show that coal arenes of the raw coals are converted into nitro-arenes in structurally modified coals(SMCs)in both the media,the corresponding bands at 1550-1490 and 1355-1315 cm^(-1) respectively.FTIR study confirms that nitration is the predominant phenomenon,though,oxidation and nitration phenomena takes place simultaneously during treatment with nitric acid to form SMCs.In comparison to raw coals,the SMCs show higher aromaticity and may be easily converted to coal derived products like activated carbon and specialty carbon materials.

关键词： Coal Micro-structure Nitration XRD FTIR

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：