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Microstructure studies of air-plasma-spray-deposited ConiCrAlY coatings before and after thermal cyclic loading for high-temperature application

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International journal of Minerals,Metallurgy and Materials 2016年第8期23卷 934-942页

作者： Dipak Kumar K.n.Pandey Dipak Kumar Das Mechanical Engineering Department Motilal Nehru National Institute of TechnologyAllahabad-211004India Defense Metallurgical research Laboratory Hyderabad-500058India

In the present study, bond-coats for thermal barrier coatings were deposited via air plasma spraying（APS） techniques onto Inconel 800 and Hastelloy C-276 alloy substrates. Scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, X-ray diffraction（XrD）, and atomic force microscopy（AFM） were used to investigate the phases and microstructure of the as-sprayed, APS-deposited Co ni Cr Al Y bond-coatings. The aim of this work was to study the suitability of the bond-coat materials for high temperature applications. Confirmation of nanoscale grains of the γ/γ′-phase was obtained by TEM, high-resolution TEM, and AFM. We concluded that these changes result from the plastic deformation of the bond-coat during the deposition, resulting in Co ni Cr Al Y bond-coatings with excellent thermal cyclic resistance suitable for use in high-temperature applications. Cyclic oxidative stability was observed to also depend on the underlying metallic alloy substrate.

关键词： thermal barrier coatings coating structure plasma spraying thermal cycle high-temperature applications microstructure studies

Ground reaction curves for circular excavations in non-homogeneous,axisymmetric strain-softening rock masses

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journal of rock Mechanics and Geotechnical Engineering 2013年第6期5卷 431-442页

作者： j.González-Cao F.Varas F.G.Bastante L.r.Alejano Department of natural resources and Environmental Engineering School of MinesUniversity of Vigo Department of Applied Mathematics University of Vigo

Fast methods to solve the unloading problem of a cylindrical cavity or tunnel excavated in elasto-perfectly plastic, elasto-brittle or strain-softening materials under a hydrostatic stress feld can be derived based on the self-similarity of the solution. As a consequence, they only apply when the rock mass is homogeneous and so exclude many cases of practical interest. We describe a robust and fast numerical technique that solves the tunnel unloading problem and estimates the ground reaction curve for a cylindrical cavity excavated in a rock mass with properties depending on the radial coordinate, where the solution is no longer self-similar. The solution is based on a continuation-like approach(associated with the unloading and with the incremental formulation of the elasto-plastic behavior), fnite element spatial discretization and a combination of explicit sub-stepping schemes and implicit techniques to integrate the constitutive law, so as to tackle the diffculties associated with both strong strain-softening and elasto-brittle behaviors. The developed algorithm is used for two practical ground reaction curve computation applications. The frst application refers to a tunnel surrounded by an aureole of material damaged by blasting and the second to a tunnel surrounded by a ring-like zone of reinforced(rock-bolted) material.

关键词： Tunnel convergence Ground reaction curves Strain-softening rock masses Tunnel with an aureole of a different material

析因设计结合响应面法分析甲烷干重整过程中通过形成碳纳米管进行二氧化碳减排(英文)

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催化学报 2014年第4期35卷 514-523页

作者： Tiago P.Braga regina C.r.Santos Barbara M.C.Sales Bruno r.da Silva Antnio n.Pinheiro Edson r.Leite Antoninho Valentini Department of Analytical Chemistry and Physical Chemistry Federal University of Ceara Department of Chemistry Federal University of So Carlos

A factorial experimental design was combined with response surface methodology(rSM) to opti-mize the catalyzed CO2 consumption by coke deposition and syngas production during the dry re-forming of CH4. The CH4 /CO2 feed ratio and the reaction temperature were chosen as the variables, and the selected responses were CH4 and CO2 conversion, the H2 /CO ratio, and coke deposition. The optimal reaction conditions were found to be a CH4 /CO2 feed ratio of approximately 3 at 700 °C, producing a large quantity of coke and realizing high CO2 conversion. Furthermore, raman results showed that the CH4 /CO2 ratio and reaction temperature affect the system's response, particularly the characteristics of the coke produced, which indicates the formation of carbon nanotubes and amorphous carbon.

关键词：二氧化碳转化响应面法碳纳米管析因设计甲烷碳减排重整管形

DSC study on temperature memory effect of niTi shape memory alloy

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中国有色金属学会会刊：英文版 2006年第B01期16卷 37-41页

作者： n. LIU W. M. HUAnG School of Mechanical and Aerospace Engineering Nanyang Technological University Singapore 639798

A systematic study on the temperature memory effect (TME) in a polycrystalline niTi shape memory alloy was presented. The investigation was carried out through a series of differential scanning calorimeter (DSC) tests. Two types of tests were conducted, namely single-step test and multi-step test. The influence of the step temperature on the peak/trough temperatures in the subsequent heating process and the associated energy absorption/release in the phase transformations was investigated. Using a simple theoretical model, the exact mechanism behind TME was studied.

关键词：镍钛合金形状记忆合金温度记忆效应相转变差分扫描量热计

Ground motion parameters of Shillong plateau: One of the most seismically active zones of northeastern India

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Earthquake Science 2009年第3期22卷 283-291页

作者： Saurabh Baruah Santanu Baruah naba Kumar Gogoi Olga Erteleva Felix Aptikaev j. r. Kayal Geoscience Division North-East Institute of Science and Technology (CSIR) national Geophysical research Institute Institute of Physics of the Earth School of Oceanographic Studies Jadavpur University

Strong ground motion parameters for Shillong plateau of northeastern India are examined. Empirical relations are obtained for main parameters of ground motions as a function of earthquake magnitude, fault type, source depth, velocity characterization of medium and distance. Correlation between ground motion parameters and characteristics of seismogenic zones are established. A new attenuation relation for peak ground acceleration is developed, which predicts higher expected PGA in the region. Parameters of strong motions, particularly the predominant periods and duration of vibrations, depend on the morphology of the studied area. The study measures low estimates of logarithmic width in Shillong plateau. The attenuation relation estimated for pulse width critically indicates increased pulse width dependence on the logarithmic distance which accounts for geometrical spreading and anelastic attenuation.

关键词： Shillong plateau ground motion parameter duration magnitude northeastern India

Influence of organic and inorganic properties of coal-shale on spontaneous combustion liability

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International journal of Mining Science and Technology 2019年第6期29卷 851-857页

作者： M.Onifade B.Genc n.Wagner The School of Mining Engineering University of the WitwatersrandJohannesburg 2050South Africa Department of Geology University of JohannesburgJohannesburg 2092South Africa

Coal and coal-shale undergo low-temperature oxidation when exposed to air,potentially leading to spontaneous ***-shale found in association with coal seams vary considerably in their intrinsic properties and spontaneous combustion liability *** coal-shale samples collected from four different coal mines in Witbank Coalfield,South Africa,were experimentally *** influence of coal-shale intrinsic properties and spontaneous combustion liability indices(determined by the WitsEhac Index and the Wits-CT Index)were *** liability indices indicate relationships with the intrinsic factors and thus,identifying the major intrinsic factors affecting liability toward spontaneous combustion in these coal-shale *** XrF analysis indicated that the coal-shale samples are rich in Si O2,Al2O3 and Fe2O3,while the XrD showed that same coal-shale samples are generally dominated with kaolinite and *** coal-shale occurred in association with medium rank C bituminous coal and contained varying proportion of *** Wits-Ehac Index was unable to reliably determine liability indices of some coal-shale samples,and hence the Wits-CT Index was *** results obtained from the characterisation tests may be used as a tool to predict the spontaneous combustion liability in carbonaceous material and may serve as a reference when comparing coal-shale from different coal mines.

关键词： Wits-Ehac Index Wits-CT Inde Witbank Coalfield and self-heating

TiO_(2)/WO_(3)heterogeneous structures prepared by electrospinning and sintering steps:Characterization and analysis of the impedance variation to humidity

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journal of Advanced Ceramics 2019年第2期8卷 238-246页

作者： Evando S.ArAujO Victor n.S.LEAO research Group on Electrospinning and nanotechnology Applications(GPEA-nano) Department of Materials ScienceUniversidade Federal do Vale do Sao Francisco

relative humidity(rH) is a critical environmental variable for transportation and storage of products and for the quality guarantee of several other production processes and services. Heterogeneous structures prepared from the selective semiconductor oxides may improve the sensitivity to humidity due to the better electronic and surface properties, when compared to pristine oxides. This work shows an alternative fabrication route for producing titanium dioxide/tungsten trioxide(TiO2/WO3) heterogeneous structures(by electrospinning and sintering) for potential application on the rH detection. The microstructural properties of the materials were analyzed by scanning electron microscopy(SEM), energy dispersive X-ray analysis(EDS), X-ray diffraction, and raman spectroscopy. The electrical characterization of the structures was performed by electrical impedance spectroscopy in rH range of 10%–100%. results indicated a p-to n-type conduction transition at around 30%–40% rH for all tested settings. The analysis of the impedance signature to humidity showed that the amount of fiber layers on the electrode and working temperature are important parameters to improve the humidity sensing of the TiO2/WO3 systems.

关键词： electrospinning heterogeneous structures preparation relative humidity semiconductors

Cervical spine fractures in osteopetrosis:a case report and review of the literature

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The journal of Biomedical research 2018年第1期32卷 68-76页

作者： Arjang Ahmadpour Amir Goodarzi Darrin j.Lee ripul r.Panchal Kee D.Kim Department of neurological Surgery University of California-Davis Medical Center

While management of appendicular fractures has been well described in the setting of osteopetrosis, there is limited information on managing fractures of the axial spine. Here we present an osteopetrotic patient with multiple traumatic multiple, comminuted, unstable cervical spinal fractures managed with non-operative stabilization, and provide a review of the pathophysiology, genetic characteristics, and special considerations that must be explored when determining operative versus non-operative management of spinal injury in osteopetrosis. A PubMed query was performed for English articles in the literature published up to june 2016, and used the following search terms alone and in combination：＂osteopetrosis＂, ＂spine＂, ＂fractures＂, ＂osteoclasts＂, and ＂operative management＂. Within four months after initial injury, treatment with halo vest allowed for adequate healing. The patient was asymptomatic with cervical spine dynamic radiographs confirming stability at four months. On four-year follow up examination, the patient remained without neck pain, and CT scan demonstrated partially sclerotic fracture lines with appropriate anatomical alignment. In conclusion, external halo stabilization may be an effective option for treatment of multiple unstable acute traumatic cervical spine fractures in patients with osteopetrosis. Given the challenge of surgical stabilization in osteopetrosis, further research is necessary to elucidate the optimal form of treatment in this select patient population.

关键词： osteopetrosis spine fractures osteoclasts operative management

Fuzzy Logic recursive Gaussian Denoising of Color Video Sequences via Shot Change Detection

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Circuits and Systems 2016年第8期7卷 1560-1568页

作者： V. Sasikala n. UmaMaheswari r. Venkatesh Department of Computer Science and Engineering University College of Engineering Ramanathapuram Pullangudi Tamil Nadu India Department of Computer Science and Engineering PSNA College of Engineering and Technology Dindigul Tamil Nadu India Department of Information Technology PSNA College of Engineering and Technology Dindigul Tamil Nadu India

A new technique using fuzzy in a recursive fashion is presented to deal with the Gaussian noise. In this technique, the keyframes and between frames are identified initially and the keyframe is denoised efficiently. This frame is compared with the between frames to remove noise. To do so the frames are partitioned into blocks;the motion vector is calculated;also the difference is measured using the dissimilarity function. If the blocks have no motion vectors in the block, the block of value is copied to the between frames otherwise the difference between the blocks is calculated and this value is filtered with temporal filtering. The blocks are processed in overlapping manner to avoid the blocking effect and also to reduce the additional edges created while processing. The simulation results show that the peak signal to noise ratio of the new technique is improved up to 1 dB and also the execution time is greatly reduced.

关键词： Keyframe restoration Between Frame restoration Motion Detection