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The influence of jaw's curvature on the results of the Brazilian disc test

Journal of Rock Mechanics and Geotech.ical Engineering 2016年第2期8卷 127-146页

作者： ch.F.Markides S.k.kourkoulis Department of Mechanics School of Applied Mathematical and Physical SciencesNational Technical University of Athens

The general contact problem of a disc squeezed between jaws of arbitrary curvature is considered employing Muskhelishvili’s complex *** advantage of the general solution introduced,the closed-form expressions for the stresses along strategic loci(loaded rim,loaded diameter,disc’s center)are obtained,in terms of the ratio r of the disc’s to the jaw’s ***,the effect of r(as well as that of the relative stiffness of the disc’s and jaw’s materials dictating the contact arc)on the stress distribution along these loci is *** is concluded that,for both smooth contact(zero friction)and contact with friction,the role of the jaw’s curvature is significant not only along the disc-jaw contact arc(as it could be expected),but also all along the loaded *** the other hand,it is indicated that the stress field at the disc’s center is more or less insensitive to the jaw’s curvature assuming that r lies within the range(0,0.67)or in other words within the limits defined by the two standardized suggestions,*** of American Society for Testing and Materials(ASTM)(plane loading platens with r ? 0)and that of international Society for Rock Mechanics(iSRM)(curved jaws with r ? 0.67).The upper limit of this range is a kind of compromise between the need to make the stress field at the disc’s center independent of the boundary conditions while keeping at the same time the contact angle large enough to reduce the stress concentration and the risk for premature fracture initiation far from the disc’s *** jaws with radius of curvature exceeded by that suggested by iSRM,the stress field at the disc’s center is significantly *** for jaws with radius approaching that of the disc,the stress field at the disc’s center is dramatically distorted rendering Hondros’ formula inapplicable and the test results erroneous.

关键词： Brazilian disc test Elastic contact Complex potentials Stress field Frictional stresses

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Gastroprotective effect of the iridoid fraction from Barleria prionitis leaves on experimentally-induced gastric ulceration

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chinese Journal of Natural Medicines 2014年第10期12卷 738-744页

作者： Sunil k.Jaiswal Mukesh k.Dubey Sanjib Das ch.V.Rao Department of Pharmacy Rameshwaram Institutes of Technology & Management Department of Pharmaceutical Sciences Dibrugarh University Pharmacognosy & Ethnopharmacology Div. National Botanical Research Institute (CSIR)Rana Pratap MargLucknow 226001Uttar PradeshIndia

AiM: To study the gastroprotective effect and in vivo antioxidant potential of a standardized iridoid fraction from B. prionitis leaves(BPE) against different gastric ulcer models in rats. METHOD: The standardized iridoid fraction from BPE at 50, 100, and 200 mg/kg body weight was administered orally, twice daily for 5 days for prevention from aspirin, ethanol, cold-restraint stress(CRS), and pylorus ligation(PL)-induced ulcers. Estimation of the antioxidant enzyme activity was carried out in a CRS-induced ulcer model, and various gastric secretion parameters including volume of gastric juice, acid output, and pH value were estimated in the PL-induced ulcer model. RESULTS: BPE showed a dose-dependent ulcer protective effect in PL(18.67%–66.26% protection), aspirin(24.65%–63.25% protection), CRS(20.77%–59.42% protection), and EtOH(16.93%–77.04% protection)-induced ulcers. BPE treatment in PL-rats showed a decrease in acid-pepsin secretion, and enhanced mucin and mucosal glycoproteins. However, BPE reduced the ulcer index with significant decrease in LPO(P increase in CAT(P ivity in the CRS-induced model. CONCLUSiON: The data shows that the iridoid fraction from BPE possesses anti-ulcerogenic and antioxidant potential.

关键词： Barleria prionitis iridoid HPTLC Anti-ulcer activity Antioxidant enzymes

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identification of altitude profiles in 3D geovisualizations:the role of interaction and spatial abilities

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international Journal of Digital Earth 2019年第2期12卷 156-172页

作者： Petr kubíček Čeněk Šašinka Zdeněk Stachoň Lukáš Herman Vojtěch Juřík Tomáš Urbánek Jiří chmelík Department of Geography Faculty of ScienceMasaryk UniversityBrnoCzech Republic HUME Lab Faculty of ArtsMasaryk UniversityBrnoCzech Republic Department of Psychology Faculty of ArtsMasaryk UniversityBrnoCzech Republic Department of Computer Graphics and Design Faculty of InformaticsMasaryk UniversityBrnoCzech Republic

Three-dimensional geovisualizations are currently pushed both by technological development and by the demands of experts in various applied *** the presented empirical study,we compared the features of real 3D(stereoscopic)versus pseudo 3D(monoscopic)geovisualizations in static and interactive digital elevation *** tested 39 high-school students in their ability to identify the correct terrain profile from digital elevation ***’performance was recorded and further analysed with respect to their spatial abilities,which were measured by a psychological mental rotation test and think aloud *** results of the study indicated that the influence of the type of 3D visualization(monoscopic/stereoscopic)on the performance of the users is not clear,the level of navigational interactivity has significant influence on the usability of a particular 3D visualization,and finally no influences of the spatial abilities on the performance of the user within the 3D environment were identified.

关键词： 3D geovisualizations stereoscopic and monoscopic 3D vision spatial abilities level of navigational interactivity

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Synthesis and optical characterization of porous ZnO

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Journal of Advanced Ceramics 2013年第3期2卷 260-265页

作者： k.SOWRi BABU A.RAMAchANDRA REDDY ch.SUJATHA k.VENUGOPAL REDDY A.N.MALLikA Department of Physics National Institute of Technology WarangalWarangal-506004Andhra PradeshIndia

in this paper,a simple and cheap method to prepare porous ZnO by using zinc nitrate,ethanol and triethanolamine(TEA)is *** as-prepared sample consisted of nano and micro *** sample was calcined at 300℃,400℃and 500℃with different heating *** 500℃,the nano pores disappeared but the sample maintained its micro *** emission scanning electron microscopy(FE-SEM)pictures confirmed that the size and growth of ZnO nanoparticles depended on the heating *** infrared(iR)absorption peak of Zn-O stretching vibration positioned at 457 cm^(-1)was split into two peaks centered at 518 cm^(-1)and 682 cm^(-1)with the change of *** results confirmed that Fourier transform infrared(FT-iR)spectrum was sensitive to variations in particle size,shape and *** photoluminescence(PL)spectrum of porous ZnO contained five emission peaks at 397 nm,437 nm,466 nm,492 nm and 527 *** intensity enhanced monotonously with increase of temperature and the change was rapid between temperatures of 300℃and 500℃.This was due to the elimination of organic species and improvement in the crystallanity of the sample at 500℃.

关键词： semiconductors porous ZnO optical properties

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Quanta-A platform for rapid control and monitoring of heterogeneous rbots

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Digital Communications and Networks 2020年第4期6卷 452-462页

作者： S.Sankhar Reddy ch. Anita Agrawal Anupama k.R. E.E.E Department BITS PilaniK K Birla Goa CampusGoa403726India

Rapid prototyping,real-time control and monitoring of various events in robots are crucial requirements for research.in the fields of modular and swarm robotics.A large quantities of resources(time,man power,infrastructure,etc.)are often invested in programming,interfacing the sensors,debugging the response to algorithms during prototyping and operational phases of a robot development *** cost of developing an optimal infrastructure to efficiently address such control and monitoring requirements increases significantly in the presence of mobile *** numerous solutions have been developed for minimizing the resources spent on hardware prototyping and algorithm validation in both static and mobile scenarios,it can be observed that researchers have either chosen methodologies that conflict with the power and infrastructure constraints of the research field or generated constrained solutions whose applications are restricted to the field *** paper develops a solution for addressing the challenges in controlling heterogeneous mobile robots.A platform named Quanta-a cost effective,energy efficient and high-speed wireless infrastructure is prototyped as a part of the research.in the field of modular *** is capable of controlling and monitoring various events in/using a robot with the help of a light-weight communication protocol independent of the robot hardware architecture(s).

关键词： modular robotics Swarm robotics Concurrent control and monitoring Event scheduling Centralized/decentralized communication

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Degradation of Methylene Blue and Rhodamine B Using a New Visible Light-Responsive Photocatalyst, kSb_2PO_(8-x)N_y

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Acta Metallurgica Sinica(English Letters) 2016年第4期29卷 335-343页

作者： G.Ravi ch.Sudhakar Reddy k.Sreenu Ravinder Guje Radha Velchuri M.Vithal Department of chemistry University College of ScienceOsmania University

Potassium phosphatoantimonates, kSb2PO8 （kSbPO） and kSb2PO8-xNy （kSbPON）, are prepared by solidstate method. Urea is employed as a source of nitrogen for N-doping. Structural, morphological and optical properties of both kSbPO and kSbPON are characterized by powder X-ray diffraction （PXRD）, scanning electron microscopy, energydispersive spectroscopy, Fourier transform infrared spectroscopy and UV-visible diffuse reflectance spectroscopy. Both samples are found to crystallize in a monoclinic lattice with Cc space group. The d-lines of kSbPO and kSbPON are refined by least square fitting the PXRD data, using POWD software to obtain their unit cell parameters. The bandgap energy （Eg） of both pristine and N-doped kSbPO is found from their kubelka-Munk plot. The kSbPON/visible photocatalytic degradation of methylene blue and rhodamine B has been investigated in aqueous heterogeneous suspension. The generation of .OH in the presence of kSbPON during the photoreaction is verified by a fluorescence tech.ique using terephthalic acid （TA） as a probe.

关键词： Potassium phosphatoantimonates characterization Organic dyes Photodegradation

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Laser-Heated Diamond-Anvil Cell (LHDAC) in Materials Science Research

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Journal of Materials Science & Technology 2003年第6期19卷 518-525页

作者： N.V.chandra Shekar P.ch.Sahu k.Govinda Rajan Materials Science Division Indira Gandhi Centre for Atomic Research Kalpakkam 603 102 Tamil Nadu IndiaMaterials Science Division Indira Gandhi Centre for Atomic Research Kalpakkam 603 102 Tamil Nadu IndiaMaterials Science Division Indira Gandhi Centre for Atomic Research Kalpakkam 603 102 Tamil Nadu India

Laser-heated diamond-anvil cell (LHDAC) is emerging as the most suitable, economical and versatile tool for the measurement of a large spectrum of physical properties of materials under extreme pressure and temperature conditions. in this review, the recent developments in the instrumentation, pressure and temperature measurement tech.iques, results of experimental investigations from the literature were discussed. Also, the future scope of the tech.ique in various avenues of science was explored.

关键词： Laser heating Diamond-anvil cell High pressure-high temperature Materials synthesis,Melting phenomena Phase equilibria

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An Experimental Analysis of the Applications of Datamining Methods on Bigdata

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Journal of Autonomous intelligence 2019年第3期2卷 31-39页

作者： ch.Naga Santhosh kumar k.S.Reddy Professor CSE ANURAG Engineering CollegeJNUTHKODADAIndia Researcher Hyderabad India

Data mining is a procedure of separating covered up,obscure,however possibly valuable data from gigantic *** Data impactsly affects logical disclosures and worth *** mining(DM)with Big Data has been broadly utilized in the lifecycle of electronic items that range from the structure and generation stages to the administration organize.A far reaching examination of DM with Big Data and a survey of its application in the phases of its lifecycle won't just profit scientists to create solid *** of late huge data have turned into a trendy expression,which constrained the analysts to extend the current data mining methods to adapt to the advanced idea of data and to grow new scientific *** this paper,we build up an exact assessment tech.ique dependent on the standard of Design of *** apply this tech.ique to assess data mining instruments and Ai calculations towards structure huge data examination for media transmission checking *** contextual investigations are directed to give bits of knowledge of relations between the necessities of data examination and the decision of an instrument or calculation with regards to data investigation work processes.

关键词： Data Mining Big Data knowledge Discovery Databases Decision Tree Cloud Data Mining k-Closest Neighbor Artificial intelligence Cluster

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Microstructure and pitting corrosion resistance of AA2219 Ale Cu alloy friction stir welds e Effect of tool profile

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Defence Technology（防务技术） 2015年第2期11卷 123-131页

作者： ch VENkATA RAO G.MADHUSUDHAN REDDY k.SRiNiVASA RAO Department of Metallurgical Engineering Andhra University Defence Metallurgical Research Laboratory

AA2219 Ale Cu alloy is widely used in defence and aerospace applications due to required combination of high strength-to-weight ratio and *** of components used for defence always involves *** though the mechanical properties of the base metal are better,but the alloy suffers from poor mechanical and corrosion properties during fusion *** overcome the problems of fusion welding,friction stir welding(FSW) is recognized as an alternative solid state joining method aimed to improve the mechanical and corrosion *** profile is one of the important variables which affect the performance of the friction stir *** the present work the effect of tool profile on the microstructure and pitting corrosion of AA2219 aluminiumecopper alloy was *** backscattered diffraction results established that the grain size and orientation of weld nugget of triangle profile is finer than that of conical *** scanning calorimetric results show the evidence of precipitate dissolution during *** was found that the microstructure changes,such as grain size and its orientation precipitate dissolution during FSW influence the hardness and corrosion *** corrosion resistance of friction stir welds of AA2219 was found to be better for triangle profile tool compared to conical profile which.is attributed to material flow and strengthening precipitate morphology in various *** amount of heat generation during FSW made using triangle profile tool may be the reason for greater dissolution of strengthening precipitates in nugget zone and coarsening in thermo mechanically affected zone(TMAZ) and heat affected zone(HAZ).

关键词： Al-Cu合金搅拌摩擦焊接微观结构轮廓点蚀摩擦搅拌焊接电子背散射衍射机械性能

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QFD-Taguchi based hybrid approach.in die casting process optimization

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Transactions of Nonferrous Metals Society of china 2017年第11期27卷 2345-2356页

作者： k.ch.APPARAO Anil kumar BiRRU Department of Mechanical Engineering National Institute of TechnologyManipur 795004 India

The present research work emphasized on identifying and optimizing various significant process parameters of high pressure die casting by using QFD-Taguchi based hybrid approach.in order to yield the optimum casting density of the *** of critical process parameters,selection of appropriate orthogonal array,analysis of means and analysis of variance are employed to study the performance characteristic of the die casting *** most critical process parameters identified and optimized by QFD-Taguchi based hybrid approach,such as the injection pressure,the molten metal temperature,the plunger velocity(first and second stage)and the die temperature were explored in the experimental *** results show that injection pressure is the most significant factor among the selected *** contribution of the injection pressure to the variation of mean casting density is around61.483%.Confidence interval(Ci)has also been estimated as0.000718for95%consistency level to validate the predicted range of optimum casting density of aforesaid alloy.

关键词： high pressure die casting A380 alloy QFD tech.ique Taguchi method casting density

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