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Tribological and vibrational characteristics of AISI 316L tested at elevated temperature and 600 Torr vacuum

Defence Technology（防务技术） 2019年第1期15卷 58-64页

作者： k.Arul Raj M.P.Arunkumar P.k.c.kanigalpula M.karthikeyan Department of Mechanical Engineering Koneru Lakshmaiah Education Foundation Department of Mechanical Engineering RajaRajeswari College of Engineering

Friction and wear studies enable the investigation of material interaction between two sliding surfaces in contact. In the present investigation, the coefficient of friction and the wear resistance of AISI 316 L parts were studied under self-mating, dry sliding conditions using a pin-on-disc type configuration. The experiments were conducted at vacuum based high temperature pin-on-disc tribometer. The 4 mm diameter pin and 180 mm diameter disc were subjected to varying sliding velocities(0.5, 0.75 and 1.5 m/s) and were operated in 200, 400, 500 and 580 ℃ temperature at 600 Torr vacuum. The variation of specific wear rates with sliding velocities and different environmental conditions was studied. The morphology of sliding/rubbed surfaces was observed using Scanning Electron Microscope. In summary, it was found that a severe to mild wear transition occurred in sliding under operating conditions. Increased wear rates have been observed for 500 and 580 ℃ with increasing sliding velocity. Adhesive wear has been found to be predominant at 500 and 580 ℃ where as de-lamination has been observed at ambient temperature,200 and 400 ℃ in vacuum. The present paper also carried out the numerical analysis of the vibration behavior of AISI 316 L under thermal environment. Results revealed that at high temperature vibrational amplitude and natural frequency is significantly reduced. This can be attributed to the reduction in stiffness of the material at elevated temperatures. This high amplitude vibration during service can lead to high wear rate.

关键词： Pin-on-disc Sliding wear Vacuum De-lamination Scanning electron microscope Vibration

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DYNAMIc ANALYSIS OF A GRADIENT ELASTIc POLYMERIc FIBER

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Acta Mechanica Solida Sinica 2013年第1期26卷 9-20页

作者： k.Y.Xu k.A.Alnefaie N.H.Abu-Hamdeh k.H.Almitani E.c.Aifantis Department of Mechanics Shanghai University Department of Mechanical Engineering King Abdulaziz University Lab of Mechanics and Materials Polytechnic SchoolAristotle University

A dynamic analysis of an elastic gradient-dependent polymeric fiber subjected to a periodic excitation is considered. A nonlinear gradient elasticity constitutive equation with strain- dependent gradient coefficients is first derived and the dispersive wave propagation properties for its linearized counterpart are briefly discussed. For the linearized problem a variational formulation is also developed to obtain related boundary conditions of both classical （standard） and non-classical （gradient） type. Analytical solutions in the form of Fourier series for the fiber＇s displacement and strain fields are provided. The solutions depend on a dimensionless scale parameter （the diameter to length radio d = D/L） and, therefore, size effects are captured.

关键词： gradient elasticity polymeric fibers periodic excitations size effects

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Liver transplantation for metastatic neuroendocrine tumor: A case report and review of the literature

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World Journal of Gastroenterology 2005年第48期11卷 7676-7683页

作者： Wojciech c Blonski k Rajender Reddy Abraham Shaked Evan Siegelman David c Metz Department of Gastroenterology and Hepatology Division of Gastroenterology Department of Surgery Department of Magnetic Resonance Imaging Division

Neuroendocrine tumors are divided into gastrointestinal carcinoids and pancreatic neuroendocrine tumors. The WHO has updated the classification of these lesions and has abandoned the term ＂carcinoid＂. Both types of tumors are divided into functional and non-functional tumors. They are characterized by slow growth and frequent metastasis to the liver and may be limited to the liver for long periods. The therapeutic approach to hepatic metastases should consider the number and distribution of the liver metastases as well as the severity of symptoms related to hormone production and tumor bulk. Surgery is generally considered as the first line therapy. In patients with unresectable liver metastases, alternative treatments are dependent on the type and the growth rate. Initial treatments consist of long acting somatostatin analogs and/or interferon. Streptozocin-based chemotherapy is usually reserved for symptomatic patients with rapidly advancing disease, but generally the therapy is poorly tolerated and its effects are short-lived. Locoregional therapy directed such as hepatic-artery embolization and chemoembolization, radiofrequency thermal ablation and cryosurgery, is often used instead of systemic therapy, if the disease is limited to the liver. However, liver transplantation should be considered in patients with neuroendocrine metastases to the liver that are not accessible to curative or cytoreductive surgery and if medical or Iocoregional treatment has failed and if there are life threatening hormonal symptoms. We report a case of liver transplantation for metastatic neuroendocrine tumor of unknown primary source and provide a detailed review of the world literature on this controversial topic.

关键词： Liver metastases, Neuroendocrine tumors Liver transplantation

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Metallic subwavelength-cavity semiconductor nanolasers

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Light(Science & Applications) 2012年第1期1卷 79-86页

作者： k.Ding c.Z.Ning School of Electrical Computerand Energy EngineeringArizona State UniversityTempeAZ 85287USA

Miniaturization has been an everlasting theme in the development of semiconductor *** important breakthrough in this process in recent years is the use of metal-dielectric composite structures that made truly subwavelength lasers *** different designs of metallic cavity semiconductor nanolasers have been proposed and *** this article,we will review some of the most exciting progresses in this newly emerging *** particular,we will focus on metallic-cavity nanolasers with volume smaller than wavelength cubed under electrical injection with emphasis on high-temperature *** devices will serve as an important component in the future integrated nanophotonic systems due to its ultra-small size.

关键词： Semiconductor Lasers Nanolasers Plasmons Plasmon Polaritons Metal cavity

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Improving the performance of query processing using proposed resilient distributed processing technique

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International Journal of Intelligent computing and cybernetics 2021年第2期14卷 158-169页

作者： c.Lakshmi k.Usha Rani Department of computer Science Sri Padmavati Mahila VisvavidyalayamTirupatiIndia

Purpose-Resilient distributed processing technique(RDPT),in which mapper and reducer are simplified with the Spark contexts and support distributed parallel query ***/methodology/approach-The proposed work is implemented with Pig Latin with Spark contexts to develop query processing in a distributed ***-Query processing in Hadoop influences the distributed processing with the MapReduce *** caters to the works on different nodes with the implementation of complex mappers and *** results are valid for some extent size of the ***/value-Pig supports the required parallel processing framework with the following constructs during the processing of queries:FOREAcH;FLATTEN;cOGROUP.

关键词： Query processing MapReduce Scalability Resilient distributed processing Spark

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kinetics of thermal decomposition of hydrated minerals associated with hematite ore in a fluidized bed reactor

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International Journal of Minerals,Metallurgy and Materials 2017年第3期24卷 229-239页

作者： P.c. Beuria S.k. Biswal B.k. Mishra G.G. Roy Institute of Minerals and Materials Technology Council of Scientific & Industrial Research Bhubaneswar-751013 India Indian Institute of Technology Kharagpur-721302 India

The kinetics of removal of loss on ignition(LOI) by thermal decomposition of hydrated minerals present in natural iron ores(i.e.,kaolinite,gibbsite,and goethite) was investigated in a laboratory-scale vertical fluidized bed reactor(FBR) using isothermal methods of kinetic *** in the FBR in batch processes were carried out at different temperatures(300 to 1200°c) and residence time(1 to 30 min) for four different iron ore samples with various LOIs(2.34wt% to 9.83wt%).The operating velocity was maintained in the range from 1.2 to 1.4 times the minimum fluidization velocity(Umf).We observed that,below a certain critical temperature,the FBR did not effectively reduce the LOI to a desired level even with increased residence *** results of this study indicate that the LOI level could be reduced by 90% within 1 min of residence time at 1100°*** kinetics for low-LOI samples(cates two different reaction mechanisms in two temperature *** lower temperatures(300 to 700°c),the kinetics is characterized by a lower activation energy(diffusion-controlled physical moisture removal),followed by a higher activation energy(chemically controlled removal of LOI).In the case of high-LOI samples,three different kinetics mechanisms prevail at different temperature *** temperature up to 450°c,diffusion kinetics prevails(removal of physical moisture);at temperature from 450 to 650°c,chemical kinetics dominates during removal of matrix *** temperatures greater than 650°c,nucleation and growth begins to influence the rate of removal of LOI.

关键词： thermal decomposition fluidized beds kinetic analysis hydrated iron ore activation energy

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Liquid-liquid extraction and separation of total rare earth(RE) metals from polymetallic manganese nodule leaching solution

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Journal of Rare Earths 2015年第2期33卷 207-213页

作者： P.k.Parhi k.H.Park c.W.Nam J.T.Park Mineral Resources Research Division Korea Institute of Geoscience & Mineral Resources (KIGAM)Daejeon 305-350 Republic of Korea School of Applied Science and center of Industrial Technology KIIT UniversityBhubaneswar 751024 Odisha India

The study on the solvent extraction for quantitative and selective separation of total rare earth metals from the polymetallic nodule leach liquor was investigated. The typical leach liquor bearing 0. 094 g/L total rare earth, 0. 23 g/L Mn, 0.697 g/L cu, 0.2 g/L Fe, 0.01 g/L co and 0.735 g/L Ni was subjected to the removal iron content by precipitation method using ca（OH）2 at pH 3.95, prior to solvent extraction of rare earth metals. Three different organo-phosphoric acid reagents（D2EHPA, Pc88 A, cyanex 272） were used to ascertain their performances and selectivity towards the loading of rare earth metals in presence of other base metals. Based on the results of eq. pH effect, the performances of above three extractants followed the order as： D2EHPA〉Pc88A〉cyanex 272. To ensure the absence of extraction of base metals（cu, co, Ni）, the eq. pH of the solution was optimized at the level of 2.21, though higher rare earth metal extraction efficiency was observed at higher eq. pH with either of the extractants. The complete process flow diagram for substantial recovery of total rare earth was developed using D2 EHPA. Extraction isotherm plot was constructed at A：O=12：1, 3-stages and pHe=2.21, using 0.8 mol/L D2 EHPA and the predicted condition of this study was further confirmed by 6-cycles counter current Simulation（ccS） study. The stripping of total rare earth from loaded organic phase（LO） was conducted using Hcl solution. Mc-cabe Thiele diagram study carried out at A：O=1：5 using 4 mol/L Hcl showed that three theoretical stages were needed for quantitative stripping of total rare earth. The subsequent stripped solution resulted thus led to contain total rare earth of 5.6 g/L indicating a very high enrichment of total metals by solvent extraction（SX） process.

关键词： total rare earth (RE) metals SX D2EHPA Hcl deep sea nodule

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Study on kinetics of thermal decomposition of low LOI goethetic hematite iron ore

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International Journal of Mining Science and Technology 2017年第6期27卷 1031-1036页

作者： Beuria P.c. Biswal S.k. Mishra B.k. Roy G.G. Mineral Processing Department CSIR–Institute of Minerals and Materials TechnologyBhubaneswar 751013India Indian Institute of Technology Kharagpur 721302India

In the present study, the kinetics of thermal decomposition of hydrated minerals associated in natural hematite iron ores has been investigated in a fixed bed system using isothermal methods of kinetic analysis. Hydrated minerals in these hematite iron ores are kaolinite, gibbsite and goethite, which contribute to the loss on ignition(LOI) during thermal decomposition. Experiments in fixed bed have been carried out at variable bed depth(16, 32, 48 and 64 mm),temperature(400-1200 ℃) and residence time(30,45, 60 and 75 min) for iron ore samples. It is observed that beyond a certain critical bed depth(16 mm), 100% removal of LOI is not found possible even at higher temperature and higher residence time. Most of the solid-state reactions of isothermal kinetic analysis have been used to analyze the reaction mechanism. The raw data are modified to yield fraction reacted "α" versus time and used for developing various forms of "α" functions.f(α) is the inverse of first derivative of g(α) with respect to α. The study demonstrates that decomposition of hydrated mineral in hematite follows the chemical *** estimated activation energy values in all the experimental situations are found to high, of the order of 60 kJ/mol, reinstating that the reactions are indeed controlled by moving phase boundary and random nucleation.

关键词： Loss on ignition Goethite kaolinite Gibbsite Roasting Pellet feed kinetic analysis

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Effects of temperature, hypoxia, ammonia and nitrate on the bleaching among three coral species

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chinese Science Bulletin 2004年第18期49卷 1923-1928页

作者： ZHUBaohua WANGGuangce HUANGBo c.k.Tseng BTPJ3keyLaboratoryofExperimentalMarineBiology InstituteofOceanologyChineseAcademyofSciencesQingdao266071China TheOceancollegeofHainanUniversity Haikou570228China

coral bleaching, which is defined as the loss of colour in corals due to the loss of their symbiotic algae (commonly called zooxanthellae) or pigments or both, is oc-curring globally at increasing rates, and its harm becomes more and more serious during these two decades. The sig-nificance of these bleaching events to the health of coral reef ecosystems is extreme, as bleached corals exhibited high mortality, reduced fecundity and productivity and increased susceptibility to diseases. This decreased coral fitness is easily to lead to reef degradation and ultimately to the breakdown of the coral reef ecosystems. Recently, the reasons leading to coral bleaching are thought to be as follows: too high or too low temperature, excess ultraviolet exposure, heavy metal pollution, cyanide poison and seasonal cycle. To date there has been little knowledge of whether mariculture can result in coral bleaching and which substance has the worst effect on corals. And no research was conducted on the effect of hypoxia on corals. To address these questions, effects of tem-perature, hypoxia, ammonia and nitrate on bleaching of three coral species were studied through examination of morphology and the measurement of the number of symbi-otic algae of three coral species Acropora nobilis, Palythoa sp. and Alveopora verrilliana. Results showed that increase in temperature and decrease in dissolved oxygen could lead to increasing number of symbiotic algae and more serious bleaching. In addition, the concentration of 0.001 mmol/L ammonia or nitrate could increase significantly the expulsion of the symbiotic algae of the three coral species. Except for Acropora nobilis, the numbers of symbiotic algae of other two corals did not significantly increase with the increasing con-centration of ammonia and nitrate. Furthermore, different hosts have different stress susceptibilities on coral bleaching.

关键词：鹿角珊瑚属温度组织缺氧氨硝酸钾漂白珊瑚生态系统虫黄藻

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Flow and heat transfer of composite porous medium saturated with nanofluid

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Propulsion and Power Research 2019年第2期8卷 173-181页

作者： J.c.Umavathi k.Hemavathi Department of Mathematics Gulbarga UniversityGulbarga 585106KarnatakaIndia

The present article is concerned with the heat transfer of nanofluid saturated with porous medium sandwiched between clear viscous fluid filled in a vertical *** model is developed to analyze the behavior of nanofluids taking into account the solid volume *** governing equations are obtained based on the Darcy's law for the porous medium and Tiwari and Das model to define the *** viscous and Darcy dissipation terms are included in the energy *** transformed dimensionless governing equations are solved analytically using regular *** are carried out on the flow characteristics for different values of Grashof number,Brinkman number,solid volume fraction and porous parameter using water as base fluid and copper as *** and heat transfer are also observed using five different types of *** is found that the maximum value of Nusselt number is obtained for silver nanoparticle.

关键词： Nanofluid Porous matrix Viscous fluid Vertical channel

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