143,699 research outputs found
Alkaline rocks and their economic and geodynamic significance through geological time
No full textAlkaline igneous rocks have a relative excess of alkalis over silica. Most are silica undersaturated and contain normative nepheline and real feldspathoids (nepheline, leucite). Although alkaline rocks make up only about 1% of total igneous rocks by volume, their diverse mineralogy accounts for 90% of all igneous rock names proposed by the IUGS. They occur in all tectonic settings; in the ocean basins and on the continents, along mid-ocean ridges (rare), on oceanic islands, in subduction zones in the oceans and along continental margins, as well as along rift zones. Alkaline rocks commonly include alkali basalts and foidites, tephrites, phonolites, trachytes and their intrusive equivalents, including lamprophyres and carbonatites. In the literature, a plethora of local names for alkaline rocks from different localities have been created and many geoscientists still consider them as petrological curiosities. However, their study can significantly aid the interpretation of mantle evolution, ancient terranes and their geodynamic settings. Additionally, alkaline rocks may host world-class precious- and rare-metal mineralization. During recent years, the exploration interest in critical and rare metal deposits (Nb, rare earth elements (REEs) and Th) has increased dramatically as they represent vital resources for the so-called ‘green energy transition’. This Special Publication presents new comprehensive data, results and findings on alkaline rocks from different terranes worldwide and uses their mineralogy and geochemical fingerprints in order to elucidate their petrogenesis, tectonic settings and mineralization potential. This volume is not only of interest for igneous petrologists, but also for exploration geologists prospecting for precious- and rare-metal mineralization worldwide
Microbial Extraction of Uranium from Ores
No full textCONTENTS
3.1 Introduction
3.2 Uranium Leaching Methodologies
3.2.1 Chemical Leaching
3.2.2 Bioleaching
3.3 Modes and Mechanism of Uranium Bioleaching
3.3.1 Direct Mechanism
3.3.2 Indirect Mechanism
3.3.3 Bioleaching by Heterotrophs
3.4 Factors Influencing Bioleaching
3.4.1 Mineralogy of the Ore
3.4.2 Microorganisms
3.4.3 Temperature
3.4.4 pH
3.4.5 Nutrients and Energy Source
3.4.6 Importance of Iron Oxidation
3.4.7 Sulphur Reduction
3.5 Bioleaching Techniques
3.5.1 Laboratory Investigations
3.5.1.1 Submerged Leaching
3.5.1.2 Column/Percolation Bioleaching
3.5.2 Large Scale/Industrial Operations
3.5.2.1 Dump Leaching
3.5.2.2 Heap Leaching
3.5.2.3 In Situ Leaching
3.5.2.4 Tank Leaching
3.6 Bioleaching of Uranium in the Indian Scenario.
3.7 Conclusions
Reference
Microbial Biodesulphurisation of Coal
No full text6.1 Introduction
6.2 Coal Reserves and Production
6.2.1 Global Coal Scenario
6.2.1.1 Coal Production
6.2.2 Coal Reserves in India
6.2.2.1 Coal Production in India
6.2.2.2 Categorisation of Coal in India
6.2.2.3 Grades of Coal in India
6.3 High Sulphur Coal
6.3.1 Chemistry of Sulphur in Coal
6.3.1.1 Sulphur in Coal: A Worldwide Problem
6.3.1.2 Sulphur Content in Indian Coal
6.3.1.3 Need for Desulphurisation
6.4 Desulphurisation Processes
6.4.1 Physical Methods of Desulphurisation
6.4.2 Chemical Methods of Desulphurisation
6.4.3 Bio-Desulphurisation and Microorganisms
6.4.3.1 Bio-Removal of Pyritic Sulphur
6.4.3.2 Bio-Desulphurisation of Organic Sulphur
6.4.3.3 Mechanisms of Organic Sulphur Removal
6.5 Future Research Directions
Reference
Hydrological Changes in the Arctic, the Antarctic, and the Himalaya
No full textThe chapter enumerates the importance of glaciers on global climate, livelihood, economics, and their hydrological implications. Climate warming has raised an alarming signal on water reserves, especially on Earth's cryosphere that acts as hydrological insurance for glacier-fed rivers and a key driver for the ocean ecosystem through their freshwater supply and salinity regulation. Key issues have been discussed to understand the cryosphere system and its effect on the hydrological systems
Figure 4 from: Pandey TR, Jin X-H (2021) Taxonomic revision of Habenaria josephi group (sect. Diphyllae s.l.) in the Pan-Himalaya. PhytoKeys 175: 109-135. https://doi.org/10.3897/phytokeys.175.59849
No full textFigure 4 Habenaria josephiA habit B floral bract C pedicellate ovary with spur D petal E dorsal sepal F lateral sepal G lip (A photographed from FLPH Expedition 13-0845, PE B–G drawn from the same specimen by T.R. Pandey)
Figure 16 from: Pandey TR, Jin X-H (2021) Taxonomic revision of Habenaria josephi group (sect. Diphyllae s.l.) in the Pan-Himalaya. PhytoKeys 175: 109-135. https://doi.org/10.3897/phytokeys.175.59849
No full textFigure 16 Habenaria szechuanicaA habit B floral bract C pedicellate ovary with spur D petal E dorsal sepal F lateral sepal G lip (A photographed from Hengduan Mountain Team 02687, PE B–G drawn from the same specimen by T.R. Pandey)
Prosodic issues in synthesising thadou, a tibeto-burman tone language
No full textGibbon D, Pandey P, Haokip DMK, Bachan J. Prosodic issues in synthesising Thadou, a Tibeto-Burman tone language. In: Interspeech 2009. ISCA: ISCA; 2009: 500-503
Social-ecological vulnerability to climate change in the Nepali Himalaya
No full textAbstract not availableRishikesh Pandey, Douglas K. Bardsle
Deep Learning-Based Femoral Cartilage Automatic Segmentation in Ultrasound Imaging for Guidance in Robotic Knee Arthroscopy
No full textIn final from 18 October 2019.Knee arthroscopy is a minimally invasive surgery used in the treatment of intra-articular knee pathology which may cause unintended damage to femoral cartilage. An ultrasound (US)-guided autonomous robotic platform for knee arthroscopy can be envisioned to minimise these risks and possibly to improve surgical outcomes. The first necessary tool for reliable guidance during robotic surgeries was an automatic segmentation algorithm to outline the regions at risk. In this work, we studied the feasibility of using a state-of-the-art deep neural network (UNet) to automatically segment femoral cartilage imaged with dynamic volumetric US (at the refresh rate of 1 Hz), under simulated surgical conditions. Six volunteers were scanned which resulted in the extraction of 18278 2-D US images from 35 dynamic 3-D US scans, and these were manually labelled. The UNet was evaluated using a five-fold cross-validation with an average of 15531 training and 3124 testing labelled images per fold. An intra-observer study was performed to assess intra-observer variability due to inherent US physical properties. To account for this variability, a novel metric concept named Dice coefficient with boundary uncertainty (DSCUB) was proposed and used to test the algorithm. The algorithm performed comparably to an experienced orthopaedic surgeon, with DSCUB of 0.87. The proposed UNet has the potential to localise femoral cartilage in robotic knee arthroscopy with clinical accuracy.M. Antico, F. Sasazawa, M. Dunnhofer, S.M. Camps, A.T. Jaiprakash, A.K. Pandey, R. Crawford, G. Carneiro, and D. Fontanaros
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
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