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Gouge stability controlled by temperature elevation and obsidian addition in basaltic faults and implications for moonquakes

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International Journal of Mining Science and Technology 2024年第9期34卷 1273-1282页

作者： Shutian Cao Fengshou Zhang Mengke An derek Elsworth Manchao He Hai Liu Luanxiao Zhao Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical&Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China Department of Energy and Mineral Engineering EMS Energy Institute and G3 CenterThe Pennsylvania State UniversityUniversity ParkPA 16802USA Department of Geosciences The Pennsylvania State UniversityUniversity ParkPA 16802USA State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology-BeijingBeijing 100083China School of Civil Engineering Guangzhou UniversityGuangzhou 510006China School of Ocean and Earth Sciences Tongji UniversityShanghai 200092China

Basalt is a major component of the earth and moon *** composition and temperature influence frictional instability and thus the potential for seismicity on basaltic *** performed velocitystepping shear experiments on basalt gouges at a confining pressure of 100 MPa,temperatures in the range of 100-400℃ and with varied obsidian mass fractions of 0-100%under wet/dry conditions to investigate the frictional strength and stability of basaltic *** observe a transition from velocity-neutral to velocity-weakening behaviors with increasing obsidian *** frictional stability response of the mixed obsidian/basalt gouges is characterized by a transition from velocitystrengthening to velocity-weakening at 200℃ and another transition to velocity-strengthening at temperatures>300℃.Conversely,frictional strengths of the obsidian-bearing gouges are insensitive to temperature and wet/dry *** results suggest that obsidian content dominates the potential seismic response of basaltic faults with the effect of temperature controlling the range of seismogenic ***,shallow moonquakes tend to occur in the lower lunar crust due to the corresponding anticipated higher glass content and a projected temperature range conducive to velocity-weakening *** observations contribute to a better understanding of the nucleation mechanism of shallow seismicity in basaltic faults.

关键词： Fault stability Basaltic fault Temperature elevation Obsidian content Shallow moonquakes

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Measuring powder flowability with a modified Warren Spring cohesion tester

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Particuology 2011年第2期9卷 148-154页

作者： Salam A.Mohammed Ezzat C.Abdullah derek Geldart Abdul Aziz A.Raman Department of Chemical Engineering Faculty of EngineeringUniversity of Malaya Powder Research Ltd. Harrogate& University of Leeds

The measurement of powder flowability is a major concern for most industrial processes that deal with the handling of bulk solids as raw materials, intermediates, or products. The development of devices that measure the flowability of non-aerated powders has not progressed as rapidly as might have been hoped since most research activities have been based on various types of shear testers intended to aid the design of hoppers. A new flowability indicator named as weighted cohesion （WS） is established using newly improved version of direct cohesion texture. A cornerstone of the proposed technique is that the procedure is automated, using a digital Warren Spring tester called Warren Spring-University of Malaya cohesion tester （WSUMCT）, thus making results operator-insensitive. Besides being a practical tool to diagnose the cohesion of experimental powders, the ratio between measured cohesion （using WSUMCT） and aerated density （using Hosokawa PT-S） provides us with a powerful technique to research fundamental particle internal cohesion forces directly and use these data to indicate the flowability. In this work, a series of fine （9.4μm） and coarse （60 μm） porous silica gel particle mixtures, and mixtures of fine （28μm） and coarse （72 μm） glass ballotini as well, were used as test powders. The results from these tests agree well with relative flowability determined on our newly driven indicator using WSUMCT. The validation of aerated weighted cohesion （WSA） as a flowability indicator was authenticated by comparing the conducted parameter with established measured Hausner ratio （HR） and angle of repose （AoR）.

关键词： Flowability Cohesion strength Hausner ratio Particle sizeAngle of reposeCohesive powder

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Generalized Baumslag-Solitar Graphs with Soluble Fundamental Groups

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Algebra Colloquium 2014年第1期21卷 53-58页

作者： Alberto L. Delgado derek J.S. Robinson Mathew Timm vDepartment of Mathematics illinois State University Normal IL 61790 USA Department of Mathematics University of Illinois at Urbana-Champaign Urbana IL 61801 USA Department of Mathematics Bradley University Peoria IL 61625 USA

It is shown that the generalized Baumslag-Solitar graphs which have soluble fundamental groups can be constructed from four simple types of graph by a process of decoration. The method of proof is elementary and emplo... 详细信息

关键词： generalized Baumslag-Solitar graph soluble fundamental group

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Transient leaf endophytes are the most active fungi in 1-year-old beech leaf litter

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Fungal Diversity 2018年第2期89卷 237-251页

作者： Marco Alexandre Guerreiro Andreas Brachmann Dominik Begerow derek Persoh AG Geobotany Faculty of Biology and BiotechnologyRuhrUniversitat BochumUniversitatsstraße 15044801 BochumGermany Faculty of Biology GeneticsLudwig-MaximiliansUniversity MunichGroßhaderner Straße 2-482152 Planegg-MartinsriedGermany

The ecological significance of fungi occurring asymptomatically inside living plant leaves is poorly *** the broad saprotrophic potential of many endophytic fungi,we hypothesized that they persist in decaying litter for an extended period of time after leaf *** assemblages were assessed by highthroughput sequencing in autumn leaves of beech(Fagus sylvatica)and in the corresponding leaf litter in 388 samples from 22 beech forest plots in three widely distant regions of Germany.A considerable proportion of the leafendophytic fungi was also found in 1-year-old ***occurrence networks revealed that the fungi formed unstructured assemblages inside the living leaves,rather than well-structured *** endophytic fungi constituted an integral part of the fungal litter community and were by far the most active fungi in 1-year-old *** therefore consider these endophytic occurrences to represent transient *** of the aboveground microbiome appears therefore to be closely connected to the process of litter *** the respective linked fungal habitat will facilitate predicting nutrient and carbon cycling and storage in forest ecosystems as well as elucidating the ecology of leaf microbiomes.

关键词： Endophytic fungi Litter fungi Plant microbiome Co-occurrence networks Litter decomposition Community assembly

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EFFECT OF COMPOSITION AND PROCESSING CONDITION ON MICROSTRUCTURAL PROPERTIES AND DURABILITY OF FLUOROPOLYMER/ACRYLIC BLENDS

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Chinese Journal of Polymer Science 2009年第1期27卷 59-69页

作者： derek L.Ho Forrest.A.Landis Diep Nguyen National Institute of Standards and Technology (NIST) GaithersburgMDUSA Pennsylvania State University YorkPAUSA Illinois Institute of Technology ChicagoILUSA

Fluoropolymer blends have been widely used as binders for exterior coatings because of their excellent resistance to ultra-violet (UV) radiation as well as to many corrosive chemical *** is known that the fluorinated component usually has a lower glass transition temperature and easily crystallizes in the final structure depending upon the blend composition and sample annealing *** investigated the effect of blend composition and annealing process (slow and fast cooling) on the surface morpho...

关键词： AFM Confocal microscopy Crystallinity Surface morphology Small angle scattering UV exposure

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Evolution and analysis of gas sorption-induced coal fracture strain data

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Petroleum Science 2020年第2期17卷 376-392页

作者： Zhanghao Liu Jishan Liu Pengzhi Pan derek Elsworth Mingyao Wei Rui Shi State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China School of Energy and Mining Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Mechanical and Chemical Engineering The University of Western Australia35 Stirling HighwayCrawleyWA 6009Australia Department of Energy and Mineral Engineering G3 Centre and Energy InstituteThe Pennsylvania State UniversityUniversity ParkPA 16802USA IoT Perception Mine Research Center China University of Mining and TechnologyXuzhou 221116JiangsuChina Key Laboratory of Tectonics and Petroleum Resources Ministry of EducationChina University of GeosciencesWuhan 430074China

Although coal swelling/shrinking during coal seam gas extraction has been studied for decades,its impacts on the evolution of permeability are still not well *** has long been recognized,but no satisfactory solutions have been *** previous studies,it is normally assumed that the matrix swelling/shrinking strain can be split between the fracture and the bulk coal and that the splitting coefficient remains unchanged during gas *** this study,we defined the fracture strain as a function of permeability change ratio and back-calculated the fracture strains at different *** the equilibrium state,the gas pressure is steady within the coal;in the non-equilibrium state,the gas pressure changes with *** equilibrium states,the back-calculated fracture strains are extremely large and may be physically impossible in some *** non-equilibrium states,two experiments were conducted:one for a natural coal sample and the other for a reconstructed *** the fractured coal,the evolution of permeability is primarily controlled by the transition of coal fracture strain or permeability from local matrix swelling effect to global *** the reconstituted coal,the evolution of pore strain or permeability is primarily controlled by the global effect.

关键词： Coal seam gas Fracture strain Experimental data Equilibrium state Non-equilibrium state

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Sensitivity analysis of a parallel-plate method for measuring the dielectric permittivity of high-voltage insulating materials

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High Voltage 2017年第3期2卷 200-204页

作者： Anton V.Vykhodtsev Behzad Kordi derek R.Oliver Department of Electrical and Computer Engineering University of Manitoba75a Chancellor's CircleWinnipegManitobaCanada R3T 5V62 Manitoba Institute for Materials University of Manitoba25 Sifton RoadWinnipegManitobaCanada R3T 2N2

Ascertaining the dielectric character of polymeric insulation materials is of particular interest for comparative studies that use accelerated ageing and samples from decommissioned *** the case of polymeric samples,the possibility of physical deformation within the sample holder adds additional variability to comparative *** readily obtainable instrumentation,this study undertakes a systematic sensitivity analysis of a parallel-plate capacitance measurement approach for polymeric materials that only has one capacitance plate in contact with the sample,avoiding issues of sample *** analysis demonstrates that the biggest contributor of uncertainty in the measurement of the relative permittivity and loss tangent is the precision with which the plate–plate and plate–sample separation is *** measurements show that the determination of loss tangent can be susceptible to uncertainties arising from electrical noise,but that these can be controlled further by utilising more refined instrumentation.

关键词： deformation plate analysis

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Organic Geochemical and Petrographic Characteristics of the Coal Measure Source Rocks of Pinghu Formation in the Xihu Sag of the East China Sea Shelf Basin: Implications for Coal Measure Gas Potential

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Acta Geologica Sinica(English Edition) 2020年第2期94卷 364-375页

作者： WANG Yang QIN Yong YANG Liu LIU Shimin derek ELSWORTH ZHANG Rui Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process Ministry of EducationChina University of Mining and TechnologyXuzhou.Jiangsu 221008China School of Resources and Earth Science.China University of Mining and Technology XuzhouJiangsu 221116China Department of Energy and Mineral Engineering G^3 Center and Energy InstituteThe Pennsylvania State UniversityUniversity Park.PA 16802.USA Jiangsu Design Institute of Geology for Mineral Resources XuzhouJiangsu 221006China Neutron Scattering Division.Oak Ridge National Laboratory Oak RidgeTN 37830USA

Coal measure source rocks, located in the Xihu Sag of the East China Sea Shelf Basin, were analyzed to define the hydrocarbon generation potential, organic geochemistry/petrology characteristics, and coal preservation conditions. The Pinghu source rocks in the Xihu Sag are mainly gas-prone accompany with condensate oil generation. The coals and shales of the Pinghu Formation are classified from "fair" to "excellent" source rocks with total organic carbon(TOC) contents ranging from 25.2% to 77.2% and 1.29% to 20.9%, respectively. The coals are richer in TOC and S1+S2 than the shales, indicating that the coals have more generation potential per unit mass. Moreover, the kerogen type of the organic matter consists of types Ⅱ-Ⅲ and Ⅲ, which the maturity Ro ranges from 0.59% to 0.83%. Petrographically, the coals and shales are dominated by vitrinite macerals(69.1%–96.8%) with minor proportions of liptinite(2.5%–17.55%) and inertinite(0.2%–6.2%). The correlation between maceral composition and S1+S2 indicates that the main contributor to the generation potential is vitrinite. Therefore, the coals and shales of the Pinghu Formation has good hydrocarbon generation potential, which provided a good foundation for coal measure gas accumulation. Furthermore, coal facies models indicates that the Pinghu coal was deposited in limno-telmatic environment under high water levels, with low tree density(mainly herbaceous) and with low-moderate nutrient supply. Fluctuating water levels and intermittent flooding during the deposition of peat resulted in the inter-layering of coal, shale and sandstone, which potentially providing favorable preservation conditions for coal measure gas.

关键词： hydrocarbon generation potential coal facies coal measure gas Pinghu Formation Xihu Sag

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Physical investigation on the behaviours of voussoir beams

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第3期12卷 516-527页

作者： Chaoshi Hu derek Apel Les Jozef Sudak Wei Victor Liu Zhaoyuan Chu School of Mining and Petroleum Engineering Department of Civil and Environmental EngineeringUniversity of AlbertaEdmontonT6G 1H9Canada Department of Mechanical and Manufacturing Engineering University of CalgaryCalgaryT2N 1N4Canada Anhui Yitong Construction Consulting and Management Ltd.YuexiAnqing246000China

It is important to understand the behaviour of voussoir beams in the design of underground *** are a large number of discrepancies between the re sults obtained by differe nt researchers so *** resolve these discrepancies,physically testing the stress distribution at the mid span and abutment of voussoir beam is the *** this paper,a simple two-block voussoir beam was built with loading *** displacement and strain of the voussoir beam were measured by a digital image correlation *** strain distribution along the joints of voussoir beams was firstly ***,the relationship between transverse load and midspan displacement of voussoir beam was *** is found that the stress distributions at the midspan and abutment are different both in shape and *** stress distribution is changing as the loading changes as well.

关键词： Voussoir beam Stress distribution Image correlation

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Perforation optimization of layer-penetration fracturing for commingling gas production in coal measure strata

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Petroleum Science 2022年第4期19卷 1718-1734页

作者： Bing Hou Zhuang Cui Ji-Hui Ding Feng-Shou Zhang Li Zhuang derek Elsworth State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum-BejingBejing102249China MOE Key Laboratory of Petroleum Engineering in China University of Petroleum Beijing 102249China Department of Geophysics Stanford University397 Panama MallStanfordCA94305USA Department of Geotechnical Engineering Tongji UniversityShanghai200092China Korea Institute of Civil Engineering and Building Technology Goyang10223South Korea The Pennsylvania State University University ParkPA16802USA

Optimization of fracturing perforation is of great importance to the commingling gas production in coal measure *** this paper,a 3 D lattice algorithm hydraulic fracturing simulator was employed to study the effects of perforation position and length on hydraulic fracture propagation in coal measures of the Lin-Xing block,*** on field data,three lithologic combinations are simulated:1)a thick section of coal seam sandwiched by sandstones;2)a thin coal seam layer overlay by gas-bearing tight sandstone;3)two coal seams separated by a thin layer of *** simulation shows that perforation position and length in multi-layer reservoirs play a major role in hydraulic fracture *** maximum stimulated volume requires consideration of lithologic sequence,coal seam thickness,stress states,and rock *** improve the combined gas production in coal measure strata,it is possible to simultaneously stimulate multiple coal seams or adjacent gas-bearing *** these cases,perforation location and length also significantly impact fracture propagation,and therefore should be carefully *** simulation results using 3 D lattice algorithm are qualitatively consistent with laboratory physical simulation.3 D lattice models can be used to effectively simulate the fracture propagation through layers in coal measure *** numerical results provide guidance for perforation optimization in the hydraulic fracturing of coal measure strata.

关键词： Coal measure strata Combined production 3D lattice algorithm Perforation scheme optimization Fracture propagation

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