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Analysis of monitored ground support and rock mass response in a longwall tailgate entry

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international Journal of Mining science and Technology 2018年第1期28卷 43-51页

作者： g.s.Esterhuizen D.F.gearhart i.B.Tulu NiOsH Pittsburgh Mining Research Division PittsburghPA 15236USA West Virginia University MorgantownWV 26506USA

A comprehensive monitoring program was conducted to measure the rock mass displacements, support response, and stress changes at a longwall tailgate entry in West *** was initiated a few days after development of the gateroad entries and continued during passage of the longwall panels on both sides of the *** included overcore stress measurements of the initial stress within the rock mass, changes in cable bolt loading, standing support pressure, roof deformation, rib deformation,stress changes in the coal pillar, and changes in the full three-dimensional stress tensor within the rock mass at six locations around the monitoring *** the passage of the first longwall, stress measurements in the rock and coal detected minor changes in loading while minor changes were detected in roof *** a result of the relatively favorable stress and geological conditions, the support systems did not experience severe loading or rock deformation until the second panel approached within 10–15 m of the instrumented *** reaching the peak loading at about 50–75 mm of roof sag, the cable bolts started to unload, and load was transferred to the standing *** standing support system was able to maintain an adequate opening inby the shields to provide ventilation to the first crosscut inby the face, as *** results were used to calibrate modeled cable bolt response to field data, and to validate numerical modeling procedures that have been developed to evaluate entry support *** is concluded that the support system was more than adequate to control the roof of the tailgate up to the longwall face *** monitoring results have provided valuable data for the development and validation of support design strategies for longwall tailgate entries.

关键词： Longwall mining support Tailgate Monitoring Coal mining

Temporal Behaviour of a Corner separation in a Radial Vaned Diffuser of a Centrifugal Compressor Operating near surge

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Journal of Thermal science 2013年第6期22卷 555-564页

作者： A.Marsan i.Trébinjac s.Coste g.Leroy Laboratoire de Mécanique des Fluides et d'Acoustique UMR CNRS 5509 cole Centrale de Lyon Turbomeca Safran group

The temporal behaviour of a flow separation in the hub-suction side comer of a transonic diffuser is studied thanks to unsteady numerical simulations based on the phase-lagged approach. The validity of the numerical re- sults is confn＇med by comparison with experimental unsteady pressure measurements. An analysis of the instan- taneous skin-friction pattern and particles trajectories is presented. it highlights the topology of the separation and its temporal behaviour. The major result is that, despite of a highly time-dependent core flow, the separation is found to be a ＂fixed unsteady separation＂ characterized by a fixed location of the main saddle of the separation but an extent of the stall region modulated by the pressure waves induced by the impeller-diffuser interaction.

关键词： Corner separation Radial Vaned Diffuser Centrifugal Compressor surge

Laminar Forced Convection in Curved Channel with Vortex structures

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Journal of Thermal science 2004年第2期13卷 143-149,162页

作者： A.A. AVRAMENKO s.g. KOBZAR i.V. sHEVCHUK A.V. KUZNETsOV B.i. BAsOK institute of Engineering Thermophysics National Academy of SciencesKievUkraine Center for Energy Research National University of MexicoAp.P.3462580TemixcoMor.Mexico Dept.of Mechanical and Aerospace Engineering North Carolina State UniversityCampus Box 7910RaleighNC 27606-7910USA

Theoretical and experimental investigations of heat transfer in flat curvilinear channel have been carried out. Linear and non-linear effects of Dean vortexes on intensity of heat transfer were taken into account. The linear effect, which describe harmonic (sinuous) variation of the heat transfer coefficient near the concave surface of the channel and the non-linear effect causes the general increase of the heat transfer coefficient due to augmentation of heat transfer engendered by the Dean vortexes. For both effects, mathematical relations were obtained in the form of quadratures. These numerical results were modified to the form convenient in engineering calculations. The investigations have shown that both linear and nonlinear components grow up with the Dean number. Nonlinear component Q0T increases more abruptly, while the linear one Q1T is more conservative. This is a confirmation of stability of vortex structures.

关键词： heat transfer Dean vortexes curvilinear channel quadrature.

investigation of the transformation of organic matter of carbonate deposits of the semiluksky-Mendymsky horizon under hydrothermal conditions

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Petroleum 2024年第2期10卷 216-223页

作者： s.M.Petrov A.i.Lakhova E.g.Moiseeva A.g.safiulina institute of Petroleum Chemistry and NanotechnologiesKazan National Research Technological UniversityKazan420015Russia institute of geology and Oil and gas Technologies Kazan Federal UniversityKazan420008Russia

The paper presents the results of studies on the transformation of the organic matter of siliceous-clayey carbonate rocks of the semiluksko-Mendymsky horizon of the Romashkino oil field in a hydrothermal fluid for an hour(with a water-to-rock ratio of 33)at 340℃and 380℃and pressu res of 17 and 20 *** a result of hydrothermal treatment,at 340℃and 17 MPa,based on nitrogen porosimetry and electron microscopy data,transformations of rock-forming minerals in the rock are *** lead to an increase in the volume and average diameter of mesopores in it and the formation of micropores,as well,which improve its filtration *** the same time,the amount of kerogen in the composition of the organic matter decreases and the yield of the petroleum hydrocarbon extract increases,in which,according to the sARA analysis,the content of asphaltenes increases and the content of resins,aromatic and saturated hydrocarbons *** the composition of aroatic hydrocarbons,the proportion of a lkyltri methyl benzenes and dibenzothiophenes increases,phenanthrene homologues appear,and in the composition of saturated hydrocarbons,the amount of iso-structure alkanes decreases relative to the content of linear *** the temperature and pressure of the hydrothermal fluid to 380℃and 20 MPa increases the degree of kerogen conversion from 12.4%to 23.6%.At the same time,changes occurring in the component composition of petroleum hydrocarbon extracts remains similar to the experiments carried out at 340℃and 17 MPa;the content of naphthalenes decreases,the content of dibenzothiophenes increases and C_(11)-C_(17),C_(19)-C_(22)alkyltrimethylbenzenes *** to iR spectroscopy,with increasing temperature and pressure of the hydrothermal fluid the intensity of the absorption bands of the aromatic ring,aliphatic fragments,and oxygen-containing groups increases in resins;the structural-group composition of asphaltenes changes little:aromaticity and the content of conde

关键词： Carbonate deposits Organic matter Hydrothermal fluid Mobile hydrocarbons

groundwater occurrence and flow patterns in the ishiagu mining area of southeastern Nigeria

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Frontiers of Earth science 2012年第1期6卷 18-28页

作者： i.C.EZEKWE E.ODUBO g.N.CHiMA i.s.ONWUCHEKWA Department of geography and Environmental Management Niger Delta UniversityWilberforce IslandPMB 071YeneganaNigeria Department of geography and Planning Abia State UniversityPMB 2000UtumNigeria

The ishiagu area is a water scarce region and has played host to mining activities for more than four decades. Mining-related activities have become a threat to potable water supply in the area. This paper is an attempt to show the extent of this threat and in particular, investigate the regional groundwater occurrence and flow pattem based on gPs, water well and geological data. This basin- wide model can be used for further groundwater assess- ment, pollution control and contaminant management. groundwater occurs between 2.4 and 9 m in the Lekwesi- Lokpaukwu area; 1.5-3.7 m in the Ndi-Ugbugbor-Ayaragu axis and 1.2-4.6 m in the ishiagu area. Recharge areas include the Leru-Amaubiri-Lekwesi sandstone hills and the ihetutu-Ugwuajirija mine field. While the ultimate sink of contamiants is the ivo River system, other discharge axis is the ishiagu-Ayaragu axis and the Ogwor Ndi- Ugbugbor zone. An unconfined and a confined （〉 10） circulation groundwater system was inferred, and flow model reveals that a large part of ishiag-Ayaragu and Ndi- Ugbugbor part of the study area suffer polluted recharge from the Pb/Zn mining area. groundwater was also subjected to hierarchical cluster analysis and the existence of 3-4 hydrological regimes, which revealed： Unpolluted recharge areas, areas affected by polluted recharge, a deep water and shallow water circulation and mine effluents.

关键词： groundwater flow mining heavy metals,pollution cluster analysis ishiagu Nigeria

Numerical analysis of fluid flow dynamics around a yawed half-submerged cylinder inside an open channel

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Journal of Hydrodynamics 2021年第1期33卷 111-119页

作者： M.i.Alamayreh A.Fenocchi g.Petaccia s.sibilla E.Persi Alternative Energy Department Al-Zaytoonah University of JordanJordanAmman Department of Civil Engineering and Architecture University of PaviaPaviaItaly

The drag and side force coefficients of a half-submerged cylinder in a free-surface flow were calculated through numerical simulations,with the aim of supporting the numerical modelling of log transport in *** variability of these coefficients with the yaw angle with respect to the flow direction and with the ratio between the flow depth and the diameter of the cylinder were *** were performed with the three-dimensional code ANsYs/CFX,employing the volume of fluid multiphase technique to reproduce the critical interaction between the free surface and the *** numerical tests,showing the rise of the drag force coefficient for increasing yaw angles passing from flow-parallel to flow-perpendicular cylinder and the peak of the side force coefficient for flow-oblique cylinder,were validated by comparison with the results of laboratory *** simulations were then extended to conditions with significant blockage in the vertical direction which had not been previously experimented,revealing a strong increase in the force coefficients for decreasing ratios between the flow depth and the cylinder diameter.A detailed description of the reproduced flow features in the proximity of the cylinder for the different cases was furthermore *** report,in addition to the analysis of the force coefficients,could serve a much wider range than that of log transport,i.e.,any case in which a floating cylinder interacts with free-surface flow.

关键词： Large woody debris(LWD)transport floating objects drag and side force coefficients vertical blockage free-surface interaction

seismic health monitoring of RC frame structures using smart aggregates

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Earthquake Engineering and Engineering Vibration 2013年第1期12卷 25-32页

作者： Wen-i Liao C.H.Lin J.s.Hwang g.song Department of Civil Engineering Taipei University of Techology (NTUT) Department of Construction Engineering Taiwan University of Science and Technology Department of Mechanical Engineering University of Houston

structural health monitoring of RC structures under seismic loads has recently attracted much attention in the earthquake engineering research community. in this study, a piezoceramic-based device called ＂smart aggregate＂ was used for the health monitoring of RC frame structures under earthquake excitations. Three RC moment frames instrumented with smart aggregates were tested using a shaketable with different ground excitation intensities. Distributed piezoceramic- based smart aggregates were embedded in the RC structures and used to monitor their health condition during the tests. The sensitivity and effectiveness of the proposed piezoceramic-based approach were investigated and evaluated by analyzing the measured responses. The displacement ductility demand of the structural members was calculated and compared with the damage index determined from the health monitoring system. The comparison shows that the damage index is compatible with the calculated ductility demand.

关键词： smart aggregate health monitoring RC frame shaketable piezoceramic

A mild, configurable, flexible CoNi-LDH（v）/Zn battery based on H-vacancy-induced reversible Zn2+ intercalation

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Journal of Energy Chemistry 2025年第1期100卷 498-508页

作者： Xinyue Cheng Dingsheng Wu Hao gao Qingqing Wang Pengfei Lv sam s.Yoon Qufu Wei Key Laboratory of Eco-textiles Ministry of Education Jiangnan University school of Mechanical Engineering Korea University

Flexible Zn-based batteries have attracted increasing research interest as essential components of wearable energy storage ***,the advancement of flexible aqueous Zn-based batteries based on Co-Ni layered double hydroxide （CoNi-LDH） as the cathode material is hampered by their poor cycling stability and the corrosiveness of alkaline ***,CoNi-LDH nanosheets enriched with H vacancies (CoNi-LDH（v）) were constructed on a flexible carbon cloth （CC） substrate via electrochemical deposition and *** Zn-based battery comprising CoNi-LDH（v）@CC as the cathode exhibited highly reversible conversion reactions and stable operation in 3 M ZnsO4electrolyte （pH=4）.The battery delivered an excellent specific capacity (225 mA h g-1,0.26 mA h cm-2),acceptable cycling stability（53.9%,900 cycles）,and high discharging *** abundant H vacancies served as active sites for the reversible intercalation of Zn2+and the extravasation of NO3-generated channels and space for Zn2+transport and storage,together enabling an excellent Zn2+storage ***,a sandwich-structured solid-state CoNi-LDH（v）@CC//Zn@CC battery was fabricated and was found to exhibit a noteworthy electrochemical performance and mechanical *** a proof of concept,the unencapsulated battery powered a digital watch under various deformation conditions and operated stably for 80 ***,the flexible battery displayed outstanding customizability,maintaining an open-circuit voltage of 1.42 V even after being cut *** proposed engineering strategy contributes to the realization of textiles with truly wearable energy-storage devices.

关键词： CoNi/Zn battery H vacancies Mild aqueous electrolyte Tailorable battery Wearable energy storage device

Magnetic properties, magnetoresistivity and magnetocaloric effect in gd_xLa_(1-x)-Mnsi alloys

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Journal of Rare Earths 2009年第4期27卷 684-687页

作者： T.i.ivanova s.A.Nikitin W.suski g.A.Tskhadadze i.A.Ovtchenkova D.Badurski Physics Department Moscow State University 119992 Moscow Russia international Laboratory of High Magnetic Fields and Low Temperatures Wroclaw Poland Polish Academy of sciences Trzebiatowski Institute of Low Temperatures and Structure Research P.O.Box 1410 50-950 Wroclaw 2 Poland

The results of magnetization, magnetoresistivity and magnetocalofic effect （MCE） studies performed on polycrystalline samples of the gdxLa1-xMnsi （x=0.5, 0.6, 0.7, 0.8, 0.9, 1.0） compounds were presented. Complex measurements were carried out on the gdxLa1-xMnsi compounds to determine the influence of substitution in the rare earth （R） sublattice on the magnetic and related properties of these compounds. The compounds with x≤0.6 demonstrated two magnetic phase transitions （ferromagnetic to paramagnetic and antiferro- magnetic to ferromagnetic） both of which were first order. Anomalies in the magnetocaloric effect, electroresistivity and magnetoresistivity were observed in the temperature ranges of the magnetic phase transitions. The temperature dependences of MCE and magnetoresistivity for these compounds correlated with the temperature dependence of magnetization.

关键词： magnetocaloric effect magnetoresistivity magnetic phase iransition itinerant magnetism rare earths