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Automation in U.S. longwall coal mining: A state-of-the-art review

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International Journal of Mining Science and Technology 2019年第2期29卷 151-159页

作者： Syd S.Peng Feng Du Jingyi Cheng Yang Li West Virginia University School of Energy Science and Engineering Henan Polytechnic University School of mines China University of Mining and Technology College of Resource and Safety Engineering China University of Mining and Technology (Beijing)

This paper reviews the development of U.S. longwall mining from an unknown to became the world standard in the past five decades with emphasis on automation. Large scale longwall face equipment were imported from Germany and United Kingdom to increase production in the 1970 s and great effort was made to improve them to suit U.S. conditions, rather than domestic market. Automation began with the development of electrohydraulic shields in 1984 and continue to present. Introduction of first generation semi-automated longwall system occurred in 1995 and step-to-step improvement continues to present following the development of sensor technology and internet of things(IOT). Since then, emphasis on new development has been concentrated on the improvement of equipment reliability, miner's health and safety as well as production, including dust control techniques, proximity sensor, anti-collision and remote control. Automation is classified into two categories: automation of individual face equipment and automation of longwall system. The automation development of longwall system is divided into three stages: shearer-initiated-shield-advance(SISA), semi-automated longwall system, and remote control shearer.

关键词： Longwall mining Automation Shield Shearer AFC

Distribution and mode of occurrence of radionuclides in phosphogypsum derived from Aqaba and Eshidiya Fertilizer Industry,South Jordan

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Chinese Journal Of Geochemistry 2010年第3期29卷 261-269页

作者： Al-Hwaiti M.S. Zielinski R.A. Bundham J.R. Ranville J.F. Ross P.E. Environmental Engineering Department Al-Hussein Bin Talal University USGS DenverCO 80225USA Environmental Science and Engineering Division Colorado School of Mines

Phosphogypsum (PG) is a by-product of the chemical reaction called the "wet process" whereby sul-phuric acid reacts with phosphate rock (PR) to produce phosphoric acid, needed for fertilizer production. Through the wet process, some impurities naturally present in the PR become incorporated in PG, including U decay-series radionuclides, are the main important concern which could have an effect on the surrounding environment and pre-vent its safe utilization. In order to determine the distribution and bioavailability of radionuclides to the surrounding environment, we used a sequential leaching of PG samples from Aqaba and Eshidiya fertilizer industry. The results showed that the percentages of 226Ra and 210Pb in PG are over those in the corresponding phosphate rocks (PG/PR), where 85% of the 226Ra and 85% of the 210Pb fractionate to PG. The sequential extraction results exhibited that most of 226Ra and 210Pb are bound in the residual phase (non-CaSO4) fraction ranging from 45%-65% and 55%-75%, respectively, whereas only 10%-15% and 10%-20% respectively of these radionuclides are distributed in the most labile fraction. The results obtained from this study showed that radionuclides are not incorporated with gypsum itself and may not form a threat to the surrounding environment.

关键词：天然放射性核素磷石膏化肥工业赋存状态 226Ra 反应产物化肥生产周围环境

Alternating Direction Implicit Orthogonal Spline Collocation on Non-Rectangular Regions

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Advances in Applied Mathematics and Mechanics 2013年第4期5卷 461-476页

作者： Bernard Bialecki Ryan I.Fernandes Department of Applied Mathematics and Statistics Colorado School of MinesGoldenCO 80401USA Department of Mathematics The Petroleum InstituteAbu DhabiUnited Arab Emirates

The alternating direction implicit(ADI)method is a highly efficient technique for solving multi-dimensional time dependent initial-boundary value problems on *** the ADI technique is coupled with orthogonal spline collocation(OSC)for discretization in space we not only obtain the global solution efficiently but the discretization error with respect to space variables can be of an arbitrarily high ***[2],we used a Crank Nicolson ADI OSC method for solving general nonlinear parabolic problems with Robin’s boundary conditions on rectangular polygons and demonstrated numerically the accuracy in various norms.A natural question that arises is:Does this method have an extension to non-rectangular regions?In this paper,we present a simple idea of how the ADI OSC technique can be extended to some such *** approach depends on the transfer of Dirichlet boundary conditions in the solution of a two-point boundary value problem(TPBVP).We illustrate our idea for the solution of the heat equation on the unit disc using piecewise Hermite cubics.

关键词： Alternating direction implicitmethod orthogonal spline collocation two point boundary value problem Crank Nicolson parabolic equation non-rectangular region

Annealing Response of Cold-Rolled Vanadium Microalloyed Sheet Steels

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Journal of Iron and Steel Research(International) 2011年第S1期18卷 404-411页

作者： John G Speer David K Matlock Robert J Glodowski A dvanced Steel Processing and Products Research Center Colorado School of MinesGoldenColorado USA East Metals (North America) LLCPittsburghPAUSA

Vanadium microalloying is widely employed in hot-rolled HSLA products;because of its relatively high solubility in austenite,vanadium plays a special role in thin-slab cast hot-rolled products where reheating is limited prior to *** cold-rolled and annealed sheet steels,vanadium technology has been employed in bake-hardenable drawing-quality steels,and in HSLA *** studies have investigated the continuous and batch annealing response of vanadium-containing cold-rolled HSLA steels,with an emphasis on aluminum and nitrogen variations (because of the special importance of nitrogen in vanadium microallyed steels,and interesting interactions between vanadium,aluminum and nitrogen).The present contribution reviews some key aspects of vanadium-microalloyed coldrolled sheet steels,and highlights the results of selected studies showing the influence of steel composition and processing.

关键词： Microalloying vanadium,bake-hardening cold rolled sheet steel

Unwrapping reworked crust at the Columbia supercontinent margin within central southern Amazon Craton using multi-source geophysics and geochronology data synergy

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Geoscience Frontiers 2022年第3期13卷 35-52页

作者： João G.Motta P.G.Betts V.T.Meira V.G.Trevisan C.R.de Souza Filho Institute of Geosciences University of CampinasCampinasSão PauloBrazil Camborne School of mines University of ExeterPenryn CampusPenrynCornwallUnited Kingdom School of Earth Atmosphere and EnvironmentMonash University(Clayton Campus)ClaytonVICAustralia Anglo American Níquel Brasil Ltda. Avenida Interlândia502 QD 87LST 68 e 10GoiâniaGoiásBrazil

The geometry and evolution of pre-existing basement in accretionary belts bordering supercontinents are often *** interpretation of long-wavelength potential field satellite data can image deep crust structure,improving our understanding of lithospheric processes that formed these margins ***,we present a multidisciplinary interpretation of the lithospheric architecture of the central southern Amazon Craton,a fragment of an accretionary belt at the southwestern Columbia supercontinent ***-borne gravity and magnetic data,airborne magnetic data,passive seismic(V_(p)/V_(s) ratio,crustal thickness)and seismic tomography data reveals that basement terranes from the interior of the craton extend into the accretionary margin of *** demonstrate a vertically heterogeneous structure with an underlying strongly reworked pre-Columbia tectonic wedge that sustained prolonged modification during the supercontinent assembly as corroborated by Nd isotope and geochronology *** isotope data suggest that the protracted orogenic wedge was influenced by subduction angle shifts over time,including addition of substantial juvenile material during slab retreat *** interplay promoted Craton growth at the supercontinent margin while keeping a subtle record of the pre-existing *** findings point to the possible misrepresentation of basement extension and geometry of supercontinent margins elsewhere.

关键词： Satellite gravity Satellite magnetics Columbia Accretionary belt Amazon Craton Geochronology

Numerical investigation of the effect of transitory strand opening on mixing in a multistrand tundish

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International Journal of Minerals,Metallurgy and Materials 2011年第5期18卷 535-542页

作者： Sabin Kumar Mishra Pradeep Kumar Jha Satish Chandra Sharma Satish Kumar Ajmani Department of Mechanical and Industrial Engineering Indian Institute of Technology RoorkeeRoorkee 247667UttarakhandIndia Steelmaking and Casting Research Group Tata SteelR&DBurma MinesJamshedpur 831007JharkhandIndia

In a multistrand,the outlet near the inlet produces short circuiting *** leads to the formation of dead zones inside the tundish,and consequently,the mean residence time *** the present study,numerical investigation of mixing inside a delta shaped tundish with sloping boundaries was carried out by solving the Navier-Stokes equation and employing the standard turbulence *** decrease the dead zone volume inside the tundish,the effect of closing the outlet near the inlet for a small amount of time and further opening it on the mixing behavior of the tundish was *** outlets near the inlet were closed for varying amount of time,and the transient analysis of fluid flow and the tracer dispersion study were carried out to find the mixing parameters of the tundish,namely,mean residence time and the ratio of mixed to dead volume of the *** optimum closure time of the near outlet has been found,which yields best mixing inside the *** numerical code was validated against the experimental observation by performing the tracer dispersion study inside a multistrand tundish and the reasonably good match between the experimental and numerical results in terms of residence time distribution （RTD） *** results obtained from the present study confirm the strong role of choosing the right time for opening and closing the outlets to get improved characteristics for the fluid flow and mixing behavior of the *** educational version of computational fluid dynamics （CFD） software PHOENICS was used to solve the governing equations and interpret the results in different forms.

关键词： continuous casting billets tundish flow simulation mean residence time dead volume computational fluid dynamics (CFD)

Trace element and Nd isotope analyses of apatite in granitoids and metamorphosed granitoids from the eastern Central Asian Orogenic Belt:Implications for petrogenesis and post-magmatic alteration

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Geoscience Frontiers 2023年第2期14卷 71-85页

作者： Xin-Yu Long Jie Tang Wen-Liang Xu Chen-Yang Sun Jin-Peng Luan Shuai Xiong Xiao-Ming Zhang College of Earth Sciences Jilin UniversityChangchun 130061China Key Laboratory of Mineral Resources Evaluation in Northeast Asia Ministry of Natural Resources of ChinaChangchun 130061China State Key Laboratory of Continental Dynamics Department of GeologyNorthwest UniversityXi’an 710069China Key Laboratory of Ministry of Education on Safe Mining of Deep Metal mines Northeastern UniversityShenyang 110819China State Key Laboratory of Superhard Materials Jilin UniversityChangchun 130012China

We present in situ trace element and Nd isotopic data of apatites from metamorphosed and metasomatized(i.e.,altered)and unaltered granitoids in the Songnen and Jiamusi massifs in the eastern Central Asian Orogenic Belt,with the aim of fingerprinting granitoid petrogenesis,including both the magmatic and post-magmatic evolution *** from altered granitoids(AG)and unaltered granitoids(UG)are characterized by distinct textures and geochemical *** from AG have irregular rim overgrowths and complex internal textures,along with low contents of rare earth elements(REEs),suggesting the re-precipitation of apatite during epidote crystallization and/or leaching of REEs from apatite by metasomatic ***(t)values of the these apatites are decoupled from zircon eHf(t)values for most samples,which can be attributed to the higher mobility of Nd as compared to Sm in certain *** from UG are of igneous origin based on their homogeneous or concentric zoned textures and coupled Nd-Hf isotopic *** element variations in igneous apatite are controlled primarily by the geochemical composition of the parental melt,fractional crystallization of other REEbearing minerals,and changes in partition *** contents and Eu/Eu^(*) values of apatites from UG correlate with whole-rock Sr and SiO2 contents,highlighting the effects of plagioclase fractionation during magma *** from UG can be subdivided into four groups based on REE *** 1 apatites have REE patterns similar to the host granitoids,but are slightly enriched in middle REEs,reflecting the influence of the parental melt composition and REE *** 2 apatites exhibit strong light REE depletions,whereas Group 3 apatites are depleted in middle and heavy REEs,indicative of the crystallization of epidote-group minerals and hornblende before and/or during apatite crystallization,*** 4 apatites are depleted in heavy REEs,but e

关键词： Eastern CAOB Granitoid petrogenesis Apatite geochemistry Fluid-induced alteration Nd-Hf isotopic decoupling Crustal assimilation

Municipal solid waste landfill site selection for the city of Sanliurfa-Turkey:an example using MCDA integrated with GIS

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International Journal of Digital Earth 2012年第2期5卷 147-164页

作者： M.Irfan Yesilnacar M.Lutfi Suzen Basak Sener Kaya Vedat Doyuran Department of Environmental Engineering Harran UniversityS¸anliurfaTurkey Department of Geological Engineering Middle East Technical UniversityAnkaraTurkey Colorado School of mines Division of EngineeringGoldenCOUSA

A municipal solid waste(MSW)management system needs solid waste management(SWM)techniques where the presence of a sanitary landfill is *** of the most important issues of sanitary landfilling is to locate the facility to an optimal *** the versatility and case-dependent nature of conventional expert-based site selection procedures,the number of sites to be chosen increases with increased population forcing a number of ***quently,constraints and environmental regulations mechanically mask unsuitable areas,leaving very little areas to be *** turns the situation into a challenging issue for a geographical information system(GIS)used with multicriteria decision analysis(MCDA),to select optimal *** study aims to apply MCDA integrated with GIS to select possible sites of a MSW landfill with the same expert and same cognitive parameters while compared with the already present *** of this study revealed that conventional expert-based methods could not always evaluate all constraints at the same time and map reproduction is limited when parameter maps are changing rapidly in *** order to produce cognitive and reproducible analyses,GIS with MCDA integration offers a good solution for site selection issue and forms a good alternative for conventional methods.

关键词： municipal solid waste(MSW) landfill site selection geographical information systems(GIS) multi-criteria decision analysis(MCDA)

Sedimentary Paleoenvironment of the Eastern Hexi Corridor, NW China: Constraints from Chert Geochemistry and Sedimentary Analysis of Early Paleozoic Strata

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Acta Geologica Sinica(English Edition) 2020年第4期94卷 1223-1237页

作者： ZHANG Yiping CHEN Xuanhua AVZUZA ZHANG Beihang ZHAO Heng Chinese Academy of Geological Sciences Beijing 100037China Nevada Bureau of mines and Geology University of NevadaReno89557USA Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China

The eastern Hexi Corridor, northwest China, is located at the tectonic junction of the Alxa Block, the North China Craton, and the Qinling-Qilian Orogen. The early Paleozoic Xiangshan Group record critical information regarding paleoenvironment, paleoclimate and paleotectonic setting, from which we here present a focused study on the chert beds within the Xiangshan Group. Through field mapping, microstructural observation, whole-rock geochemistry analyses and detrital zircon dating, we suggest that the Xiangshan Group chert was deposited along a passive continental margin, formed primarily through biological activity with minor hydrothermal influence and terrestrial input. The characteristics of the chert support a low latitude sedimentary paleoenvironmental origin, and reveal the fact that the Alxa Block was separated from the North China craton, while emerged some paleogeographic affinity with the Qilian region in the Middle-Late Cambrian.

关键词： geochemistry sedimentary paleoenvironment Early Paleozoic Xiangshan Group chert Hexi Corridor