1,720,960 research outputs found
Controls of Coal and Overburden on Acid Mine Drainage and Metal Mobilization at Makum Coalfield, Assam, India
No full textAcid mine drainage (AMD) is one of the major environmental problems faced by coal
mines throughout the world. This work addresses the geochemical characterization of
AMD, control of mineralogy of coal and mine overburden on its generation, consequent
metal enrichment and mobility in water soil, and sediments in and around the Makum
coalfields of Assam, India
Geochemical Characteristics of Talcher Coal, India: Insights on Mode of Occurrence of Trace Elements and Palaeoenvironmental Condition
No full textUnderstanding the elemental concentration and distribution in coal has significant importance in assessing its mobility and behaviour during utilisation processes. The depositional environment of coal controls the concentrations of elements that can adversely affect human health and the environment. Thus, this study investigates the detailed mineralogy and elemental composition of Talcher coal, the largest coalfield in India, in order to gain insight into the mode of occurrence of elements and palaeodepositional conditions. The coal is enriched in detrital mineral matter and exhibits a high detrital/authigenic index. Quartz and kaolinite are abundant, while siderite, calcite, plagioclase, goethite, illite, dolomite, apatite, and Ti-oxide have also been identified. This coal is enriched with Hg, Mo, Cr, and Th concerning the world hard coal. The Ti, Na, Cu, Cr, Rb, U, and Th have a strong association with silicate minerals. The Sr, K, Mg, Ca, and P exhibit both carbonate and phosphate affinities, whereas Fe, S, and Co are mostly associated with organic matter. Similarly, Mn, Ba, Ni, Zn, Pb, Cd, Mo, As, and Nb display both organic and inorganic affinities. The inorganic matters in coal are predominantly derived from intermediate rocks and have undergone strong weathering. Various elemental proxies suggest that the coal is formed predominantly in a freshwater depositional environment under a fluctuating oxygenating conditions. The Sr/Cu and Rb/Sr ratios have implied the prevalence of a warm humid climate with intermittent transitional warm to dry climatic conditions during coal formation. This research will be helpful in future palaeowetland research as well as understanding the behaviour of trace elements during coal utilisation
Limestone quarry production planning for consistent supply of raw materials to cement plant: A case study from Indian cement industry with a captive quarry
No full textA long term production planning of limestone quarry is presented to supply consistent quantity and quality of limestone to a cement plant. A case study from Indian cement industry is presented where the cement plant has a captive limestone quarry. The objectives of this study are: (a) to investigate how long the limestone quarry can alone supply the desire quality and quantity materials to the cement plant; and (b) to investigated the possibility of extending the quarry life by utilizing some quantity of the limestone from the different source and blending that limestone with the limestone from the quarry to achieve the target quality and quantity of the cement plant. These objectives are achieved by generating the production sequencing of the mining blocks using a sequential branch-and-cut algorithm. The results revealed that up to 15 years, the existing quarry alone can serve the cement plant. If certain quantity of limestone can be brought from the other sources, the life of the study quarry is significantly improved. The life of the quarry increased from 15 years to 85 years. The study also helps to calculate the desire quality of the limestone that will be brought from other sources throughout the life of the quarry
Organic petrography and stable isotopic characteristics of Permian Talcher coal, India: Implications on depositional environment
No full textThe depositional environment of coal generally controls its chemical composition, physical properties, and utilization potential. Therefore, the present study investigates the depositional environment of the Talcher coal, which represents the single largest coal reserve in India, based on proximate, ultimate and petrography analyses, as well as on the determination of stable carbon (δ13C) and nitrogen (δ15N) isotopic composition. The Talcher coal is classified as sub-bituminous to high volatile bituminous rank based on the vitrinite reflectance (0.40–0.59%), volatile matter (43.0–55.1%), and carbon content (71.2–79.3%). The ash yield varies from 12.4 to 39.3%. Petrographically, the coal is dominated by vitrinite (48.4–64.2%) followed by inertinite (21.4–36.2%) and liptinite (10.0–16.8%). The mesotrophic to rheotrophic water conditions in the palaeomire is deciphered by the vitrinite to inertinite ratio (V/I) and the groundwater index (GWI). The coal was formed in a telmatic environment where forested vegetation prevailed. The recorded TPI values (>1) indicate a high tree density. The δ13C and δ15N values of Talcher coal range from −23.7‰ to −21.7‰ and +0.6‰ and +3.4‰, respectively. The total organic carbon to total nitrogen ratio (TOC/TN) of the coal lies between 20 and 40, which reflects the dominance of vascular higher terrestrial plants as the source vegetation. The δ13C composition of coal corresponds to that of the C3 land plants. Both δ13C and δ15N composition of Talcher coal falls within their respective global coal values. The δ13C composition of the palaeoatmospheric CO2 (δ13Cair) is found to be −3.7 ± 0.5‰ and − 2.6 ± 0.5‰ applying Arens and Gröcke equations, respectively, and they are in agreement with the global Permian δ13Cair (−5.6 to −2.3‰)
Suspended sediment yield modeling in Mahanadi River, India by multi-objective optimization hybridizing artificial intelligence algorithms
No full textRiver sediment produced through weathering is one of the principal landscape modification processes on earth. Rivers are an integral part of the hydrologic cycle and are the major geologic agents that erode the continents and transport water and sediments to the oceans. Estimation of suspended sediment yield is always a key parameter for planning and management of any river system. It is always challenging to model sediment yield using traditional mathematical models because they are incapable of handling the complex non-linearity and non-stationarity. The suspended sediment modeling of the river depends on the number of factors such as rock type, relief, rainfall, temperature, water discharge and catchment area. In this study, we proposed a hybrid genetic algorithm-based multi-objective optimization with artificial neural network (GA-MOO-ANN) with automated parameter tuning model using these factors to estimate the suspended sediment yield in the entire Mahanadi River basin. The model was validated by comparing statistically with other models, and it appeared that the GA-MOO-ANN model has the lowest root mean squared error (0.009) and highest coefficient of correlation (0.885) values among all comparative models (traditional neural network, multiple linear regression, and sediment rating curve) for all stations. It was also observed that the proposed model is the least biased (0.001) model. Thus, the proposed GA-MOO-ANN is the most capable model, compared to other studied models, for estimating the suspended sediment yield in the entire Mahanadi river basin, India. The results also suggested that the proposed GA-MOO-ANN model is unable to estimate suspended sediment yield satisfactorily at gauge stations having very small catchment areas whereas performing satisfactorily on locations having moderate to the large catchment area. The models provide the best result at Tikarapara, the gauge station location in the extreme downstream, having the largest catchment area
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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