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Sesam, toward a Mature Magmatic Arc Sourced from Tholeiitic Volcanisms and Calc-Alkaline Volcanoplutonism within Kedougou-Kenieba Inlier, South-East Senegal/West Africa

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Journal of Geoscience and Environment Protection 2025年第1期13卷 331-386页

作者： Mame Codou Ndiaye Mamadou Ndiaye Papa Malick Ngom Mababa Diagne Andrea Moscariello Antoine De Haller National Superior school of mines et and Geology Cheikh Anta Diop University Dakar Senegal Geology Department Faculty of Sciences and Technics Cheikh Anta Diop University Dakar Senegal Department of Earth Sciences and Environment Amadou Makhtar Mbow University Diamniadio Senegal Department of Earth Sciences and Environment University of Genova Genova Switzerland

The Paleoproterozoic terrains of Kedougou Inlier have an overall architecture formed of greenstones and sedimentary basins. Most of the work done on these Birimian formations has focused on either belts or basins, or even briefly on both, but more rarely on the transition zones between belts and Paleoproterozoic basins. Our study focuses on the lithostructural framework of the Mako-Diale transition zone located within the Kedougou-Kenieba Inlier. Its objective is to redefine the existing architecture. Geophysical, petrographic, structural and geochemical results from lithostructural domains allowed to building a new architecture based on three major lithostructural domains evolving into tectonomagmatic complexes associated with three shear zones corresponding to Western shear-contact (CiscoW) represented by Sabodala sinistral mylonitic shear (SSZ), to Median sinistral ductile then brittle shear-contact (CiscoM) and to Eastern dextral brittle-ductile shear-contact (CiscoE) corresponding to the Main transcurrent shear (MTZ). Tectonomagmatic complexes are represented by Maco oceanic crust, Sesam arc and Diale back-arc basin. The opening of Diale basin is related to CiscoM. Its closure set along the Faleme shear-contact (CiscoF) located beyong CiscoE. The tectonic evolution of the Eburnian orogeny within Kedougou-Kenieba inlier highlights four (4) deformations phases: CiscoW, CiscoM, CiscoE and CiscoF respectively running for D1, D2, D3 et D4. Such CiscoW along Sabodala, Sofia deposits and CiscoE along Massawa deposit, CiscoM and CiscoF stand as potential host structures for futures Kedougou inlier gold deposits. Furthermore, large plutonic masses within Mako-Diale transition zone belong all to three (3) distinct magmatic sources: Koulountou granodiorite, Koulountou and Tinkoto granites are sourced from high-K mafic rocks;Tiguida granite and Diabba granodiorite from low-K mafic rocks, while Dioudioukounkou granite belongs to tonalite source. The Sesam arc is located alo

关键词： Magmatism Tholeiitic Calc-Alkaline Garnet-Granite Sesam-Arc

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Effect of irregularity on the propagation of torsional surface waves in an initially stressed anisotropic poro-elastic layer

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Applied Mathematics and Mechanics(English Edition) 2010年第4期31卷 481-492页

作者： S.GUPTA A.CHATTOPADHYAY D.K.MAJHI Department of Applied Mathematics Indian School of Mines University

The paper studies the propagation of torsional surface waves in an initially stressed anisotropic poro-elastic layer over a semi-infinite heterogeneous half space with linearly varying rigidity and density due to irregularity at the interface. The irregularity is taken in the half space in the form of a rectangle. It is observed that torsional surface waves propagate in this assumed medium. In the absence of the irregularity, the velocity equation of the torsional surface wave is also obtained. For a layer over a homogeneous half space, the velocity of torsional surface waves coincides with that of the Love waves.

关键词： irregularity torsional surface waves anisotropic initial stress

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Statistical analysis to establish an ignition scenario based on extrinsic and intrinsic variables of coal seams that affect spontaneous combustion

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International Journal of Mining Science and Technology 2019年第5期29卷 731-737页

作者： M.O.Bustamante Rúa A.J.Daza Aragón P.Bustamante Baena J.D.Osorio Botero school mines national university of colombiamedellín 050036colombia

Spontaneous combustion of coal seams in open pit mines is a problem that occurs in coal mines around the *** have been developed that express several factors which generate self-heating in the coal and favor *** synergy of these factors contributes to the increase in the temperature of oxidation reactions,facilitating the culmination of the activation energy of the system,in which the ignition develops and the reaction is ***,the incidence of each variable’s susceptibility to coal combustion is unknown,so in this work a methodology was developed to determine statistically which of the variables has the greatest contribution in the *** statistics,atypical values detection,principal component determination,cluster analysis,and logistic regression were used to determine how many indicator variables are necessary to describe susceptibility to coal *** the analysis,21,000 data from different seams of two open-pit coal mines in endwalls and abandoned pits were processed with consideration given to extrinsic and intrinsic *** temperature,atmospheric pressure,wind speed,oxygen,methane,height,ash,volatile matter,heat power,vitrinite,liptinite and the Hardgrove Index are the most influential variables in the phenomenon.

关键词： Coal fire Self-ignition Statistics analysis Open pit mines Spontaneous combustion

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Surface wave transference in a piezoelectric cylinder coated with reinforced material

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Applied Mathematics and Mechanics(English Edition) 2020年第1期41卷 123-138页

作者： K.K.PANKAJ S.A.SAHU S.KUMARI Department of Applied Mathematics Indian Institute of Technology (Indian School of Mines)

The present study deals with the propagation of a polarized shear horizontal(SH)wave in a pre-stressed piezoelectric cylinder circumscribed by a self-reinforced *** interface of the two media is assumed mechanically *** obtaining the dispersion relation,the mathematical formulation has been developed and solved by an analytical *** effects of various parameters,i.e.,the thickness ratio,the imperfect interface,the initial stress,the reinforcement,and the piezoelectric and dielectric constants,on the dispersion curve are observed *** dispersion curves for different modes have been also *** consequences of the study may be used for achieving optimum efficiency of acoustic wave devices.

关键词： shear horizontal(SH)wave piezoelectric imperfect interface self-reinforced initial stress

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CaMoO_4:Dy^(3+),K^+ near White Light Emitting Phosphor:Structural,Optical and Dielectric Properties

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Journal of Materials Science & Technology 2013年第7期29卷 633-638页

作者： S.K.Sharma S.Dutta S.Som P.S.Mandal Department of Applied Physics Indian School of MinesDhanbad 826004India

Undoped, Dy^3＋ doped and Dy^3＋, K^＋ codoped calcium molybdate phosphors have been synthesized by solid-state reaction method. X-ray diffraction studies reveal the tetragonal structure of the prepared phosphors having crystallite size 15-50 nm. Scanning electron microscopy （SEM） studies reveal the morphology and crystallite size of the prepared phosphors. Photoluminescence studies indicate that there are blue and yellow emissions at 489 and 576 nm, respectively corresponding to Dy^3＋ ion. The introduction of K＋ ion significantly influences the blue and yellow emissions which causes the near white light emission from this codoped phosphor. The intense absorption peak of the codoped phosphor at 210 nm is attributed to the band gap and a shoulder at 240 nm appears due to charge transfer from oxygen ions to neighbouring molybdenum ions. The band gap of the codoped phosphor is calculated as 5.5 eV from the absorption studies. The dielectric properties such as permittivity and dielectric loss are studied as a function of *** The authors are thankful to the Department of Science and Technology, New Delhi （Government of India） for funding this work under the Project SR/FTP/PS-087/2010.

关键词： X-ray diffraction Photoluminescence Absorption Dielectric

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Measuring absolute adsorption in porous rocks using oscillatory motions of a spring-mass system

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Chinese Journal of Chemical Engineering 2022年第4期35卷 131-139页

作者： Younki Cho Ryan Lo Keerthana Krishnan Xiaolong Yin Hossein Kazemi Petroleum Engineering Colorado School of MinesGoldenCO 80401USA

We present an oscillation-based method to measure absolute adsorption,or total gas,contained in porous rocks without and with excess *** conducted with a macroporous Berea sandstone sample in nitrogen where excess adsorption is negligible show that absolute adsorption can be obtained after the added mass of co-accelerated gas outside the sample is *** experiments conducted in propane with a crushed Niobrara shale sample with micro-and mesopores,absolute adsorption included significant excess *** subtracting both the added mass outside the sample and the gas that would be in the sample assuming no excess adsorption existed,estimated excess adsorption of propane is in good agreement with that projected based on capillary condensation of propane in the volume of mesopores.

关键词： Adsorption Porous media Shale Capillary condensation Oscillation

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Strain induced changes in performance of strained-Si/strained-Si1-yGey/relaxed-Si1-xGex MOSFETs and circuits for digital applications

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Journal of Central South University 2017年第6期24卷 1233-1244页

作者： Kumar Subindu Kumari Amrita Das Mukul K Department of Electronics Engineering Indian School of MinesDhanbad 826004India

Growing a silicon(Si) layer on top of stacked Si-germanium(Ge) compressive layer can introduce a tensile strain on the former, resulting in superior device characteristics. Such a structure can be used for high performance complementary metal-oxide-semiconductor(CMOS) circuits. Down scaling metal-oxide-semiconductor field-effect transistors(MOSFETs) into the deep submicron/nanometer regime forces the source(S) and drain(D) series resistance to become comparable with the channel resistance and thus it cannot be neglected. Owing to the persisting technological importance of strained Si devices, in this work, we propose a multi-iterative technique for evaluating the performance of strained-Si/strained-Si_(1-y)Ge_y/relaxed-Si_(1-x)Ge_x MOSFETs and its related circuits in the presence of S/D series resistance, leading to the development of a simulator that can faithfully plot the performance of the device and related digital circuits. The impact of strain on device/circuit performance is also investigated with emphasis on metal gate and high-k dielectric materials.

关键词： complementary metal-oxide-semiconductor (CMOS) high-k dielectric material inverter metal-oxide-semiconductor field-effect transistors (MOSFETs) SiGe series resistance strain

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Characterization of optical transitions of Eu^(3+) in lanthanum oxychloride nanophosphor

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Journal of Rare Earths 2011年第4期29卷 345-348页

作者： A. Choubey S. Som M. Biswas S.K. Sharma Department of Applied Physics Indian School of Mines Dhanbad 826004 India

This paper presented the studies on the optical properties and calculation of spectral parameters of europium doped lanthanum oxychloride nanophosphor for their possible applications in optoelectronic devices. The compound was doped with 0.1 mol% Eu3＋ ions. The X-ray diffraction study of prepared sample suggested the tetragonal structure with particle size in the range of 18–21 nm. The photoluminescence （PL） emission spectra showed the bright emission in orange-red region from 580 to 630 nm. The most intense emission peak at 621 nm was due to transition 5D0→7F2 in energy levels of Eu3＋ ions. The spectral parameters were calculated from the absorption and emission spectra using Judd-Ofelt intensity parameters. The calculated values of the oscillator strength corresponding to the three transitions 7F1→5D1, 7F1→5D2 and 7F0→5D2 observed at 535, 472 and 465 nm in absorption spectra were 0.30×10–6, 1.36×10–6 and 0.63×10–6, respectively. The value of transi- tion probability （A）, stimulated emission cross-section （） and radiative lifetime （τrad） corresponding to 621 nm emission peak （transition 5D0→7F2） were 308 s–1, 1.22×10–21 cm2 and 3.24×10–3 s, respectively.

关键词： X-ray diffraction optical absorption photoluminescence spectral parameters rare earths

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Effect of bioflocculants on the coagulation activity of alum for removal of trihalomethane precursors from low turbid water

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Journal of Environmental Sciences 2018年第8期30卷 1-10页

作者： Tanwi Priya Abhrajyoti Tarafdar Bramha Gupta Brijesh Kumar Mishra Department of Environmental Science and Engineering Indian Institute of Technology (Indian School of Mines)

Reactivity of chlorine towards hydrophobic groups present in natural organic matter（NOM）provokes the formation of carcinogenic disinfection byproducts such as trihalomethanes in chlorinated water. The present study aimed to investigate the variations in coagulant activity of alum using two different bioflocculants（coagulant aid） namely, Moringa oleifera and Cyamopsis tetragonoloba for the removal of hydrophobic fractions of NOM and subsequent chlorine consumption by treated water. Effect of dual coagulants on trihalomethane surrogate parameters such as total organic carbon, dissolved organic carbon, UV absorbing materials and prominent hydrophobic species such as phenolic groups along with aromatic chromophores, polyhydroxy aromatic moiety have also been studied. The concept of differential spectroscopy and absorbance slope index has been employed to understand the combined effects of alum-bioflocculants on the reactivity of NOM with chlorine. Our result shows that the combination of alum and C. tetragonoloba is more efficient for reducing trihalomethane surrogates from chlorinated water as compared to M. oleifera. C. tetragonoloba elicited synchronized effects of sweep coagulation and particle bridging-adsorption which eventually facilitated efficient removal of hydrophobic fractions of NOM. The variation in the mechanistic approach of bioflocculants was due to the presence of cationic charge on M. oleifera and adhesive property of C. tetragonoloba.

关键词： Natural organic matter Bioflocculants Disinfection byproducts Trihalomethanes Differential spectroscopy Absorbance slope index

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Designing an optimal stope layout for underground mining based on a heuristic algorithm

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International Journal of Mining Science and Technology 2015年第5期25卷 767-772页

作者： Sandanayake Don Suneth Sameera Topal Erkan Asad Mohammad Waqar Ali Mining Engineering Western Australian School of MinesCurtin University

An optimal layout or three-dimensional spatial distribution of stopes guarantees the maximum profitability over life span of an underground mining ***,stope optimization is one of the key areas in underground mine planning ***,the computational complexity in developing an optimal stope layout has been a reason for limited availability of the algorithms offering solution to this *** article shares a new and efficient heuristic algorithm that considers a three-dimensional ore body model as an input,maximizes the economic value,and satisfies the physical mining and geotechnical constraints for generating an optimal stope *** implementation at a copper deposit demonstrates the applicability and robustness of the algorithm.A parallel processing based modification improving the performance of the original algorithm in terms of enormous computational time saving is also presented.

关键词： Stope optimization Underground mining Underground mine planning Heuristic algorithm

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