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Transactions of Nonferrous Metals Society of China 2012年第3期22卷 700-710页

作者： A.VENUGOPAl Rajiv PANDA Sushant MANWATKAR K.SREEKUMAR l.rama krishna G.SUNDARARAJAN Material Characterization Division Materials and Metallurgy GroupVikram Sarabhai Space CentreThiruvananthapuram-695022India International Advanced Research Centre for Powder Metallurgy and New Materials Hyderabad-500005India

Alumina coating was formed on AA7075 aluminum alloy by micro arc oxidation（MAO） method and its corrosion and stress corrosion cracking（SCC） behaviors were examined in 3.5%（mass fraction） NaCl *** impedance spectroscopy（EIS） was used to evaluate the degradation of the coating as a function of immersion time and was modeled with appropriate equivalent *** load stress corrosion cracking（SCC） results followed by post-test metallographic observations demonstrated the usefulness of MAO coating to avoid the premature failure of the alloy due to severe localized corrosion initiated by Cu-and Fe-rich intermetallic phases.

关键词： aluminum alloy micro arc oxidation impedance spectroscopy stress corrosion

Orchestration between IlC2s and Th2 cells in shaping type 2 immune responses

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Cellular & Molecular Immunology 2019年第3期16卷 225-235页

作者： rama krishna Gurram Jinfang Zhu Molecular and Cellular Immunoregulation Section Laboratory of Immune System BiologyNational Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaMD 20892USA

The type 2 immune response is critical for host defense against large parasites such as *** the other hand,dysregulation of the type 2 immune response may cause immunopathological conditions,including asthma,atopic dermatitis,rhinitis,and ***,a balanced type 2 immune response must be achieved to mount effective protection against invading pathogens while avoiding *** classical model of type 2 immunity mainly involves the differentiation of type 2 T helper(Th2)cells and the production of distinct type 2 cytokines,including interleukin-4(Il-4),Il-5,and *** 2 innate lymphoid cells(IlC2s)were recently recognized as another important source of type 2 *** eosinophils,mast cells,and basophils can also express type 2 cytokines and participate in type 2 immune responses to various degrees,the production of type 2 cytokines by the lymphoid lineages,Th2 cells,and IlC2s in particular is the central event during the type 2 immune *** this review,we discuss recent advances in our understanding of how IlC2s and Th2 cells orchestrate type 2 immune responses through direct and indirect interactions.

关键词： Type 2 immune response type 2 T helper cell(Th2) Group 2 innate lymphoid cell(IlC2) Allergy and asthma

Tribological Properties of A356.2/RHA Composites

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Journal of Materials Science & Technology 2012年第4期28卷 367-372页

作者： D. Siva Prasad A. rama krishna Department of Mechanical Engineering GITAM University Visakhapatnam Andhra Pradesh India Department of Mechanical Engineering ANDHRA University Visakhapatnam Andhra Pradesh India

Rice husk ash （RHA） is one of the industrial waste byproduct available abundantly in the world. In the present work, an attempt is made to incorporate the RHA particles in the molten aluminum A356,2 alloy. The RHA particles were added into the matrix melt by creating a vortex with the help of a mechanical stirrer and the melt temperature was maintained between 800 and 850 ℃. Dry sliding wear experiments were performed in a pin on disc wear equipment against a chromium steel disc at 30 ℃. Scanning electron microscopy is used to study the wear characteristics of the unreinforced AI alloy and the A356.2/RHA composites. From the experiments it is observed that the composites exhibit higher hardness and resistance to wear as compared to unreinforced AI alloy,

关键词： Rice husk ash A356.2 Aluminum alloy Wear

Modeling and multi-response optimization of machining performance while turning hardened steel with self-propelled rotary tool

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Advances in Manufacturing 2015年第1期3卷 84-95页

作者： Thella Babu Rao A.Gopala krishna Ramesh Kumar Katta Konjeti rama krishna Department of Mechanical Engineering GITAM UniversityHyderabad 502329Andhra PradeshIndia Department of Mechanical Engineering University College of EngineeringJNTUKKakinada 533003Andhra PradeshIndia Productionisation & Technology Transfer Defence R&D LaboratoryKanchanbaghHyderabad 500058Andhra PradeshIndia

There are many advanced tooling approaches in metal cutting to enhance the cutting tool performance for machining hard-to-cut materials. The self propelled rotary tool （SPRT） is one of the novel approaches to improve the cutting tool performance by providing cutting edge in the form of a disk, which rotates about its principal axis and provides a rest period for the cutting edge to cool and allow engaging a fresh cutting edge with the work piece. This paper aimed to present the cutting performance of SPRT while turning hardened EN24 steel and optimize the machining conditions. Surface roughness （Ra） and metal removal rate （rMMR） are considered as machining perfor- mance parameters to evaluate, while the horizontal incli- nation angle of the SPRT, depth of cut, feed rate and spindle speed are considered as process variables. Initially, design of experiments （DOEs） is employed to minimize the number of experiments. For each set of chosen process variables, the machining experiments are conducted on computer numerical control （CNC） lathe to measure the machining responses. Then, the response surface method- ology （RSM） is used to establish quantitative relationships for the output responses in terms of the input variables. Analysis of variance （ANOVA） is used to check the adequacy of the model. The influence of input variables on the output responses is also determined. Consequently, these models are formulated as a multi-response optimi- zation problem to minimize the Ra and maximize the rMMR simultaneously. Non-dominated sorting genetic algorithm-II （NSGA-II） is used to derive the set of Pareto-optimal solutions. The optimal results obtained through the pro- posed methodology are also compared with the results of validation experimental runs and good correlation is found between them.

关键词： Self-propelled rotary turning ~ Empiricalmodeling ~ Response surface methodology (RSM) - Multi-objective formulation - Optimization - Non-dominatedsorting genetic algorithm-II (NSGA-II)

Improving Performance of a Distributed File System Using a Speculative Semantics-Based Algorithm

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Tsinghua Science and Technology 2015年第6期20卷 583-593页

作者： Talluri lakshmi Siva rama krishna Thirumalaisamy Ragunathan Sudheer Kumar Battula K l University Andhra PradeshIndia and Research ScholarJawaharlal Nehru Institute of Advanced Studies (JNIAS) ACE Engineering College

File-sharing semantics is used by the file systems for sharing data among concurrent client processes in a consistent manner. Session semantics is a widely used file-sharing semantics in Distributed File Systems(DFSs). The main disadvantage of session semantics is that writes to an open file are visible to the concurrent client processes only during their next session. Recently, "linearizability semantics" was introduced in Blob Seer DFS, in which a Read Client Process(RCP) can read only a previous version of a binary large object(blob), while update operations are carried out on that blob in a concurrent manner. In this paper, we propose a new type of file-sharing semantics, namely "speculative semantics", which permits writes to an open file to be visible to other concurrent processes provided that data consistency is not affected. In addition, we propose a new read algorithm for DFSs based on speculative semantics and a new performance measurement metric called Currency. The experimental results obtained using Blob Seer DFS indicate that the proposed read algorithm performs better than the existing read algorithm of Blob Seer DFS.

关键词： distributed system Hadoop Blobseer concurrency spe

Fabrication of ceramic coatings on the biodegradable ZM21 magnesium alloy by PEO coupled EPD followed by laser texturing process

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Journal of Magnesium and Alloys 2021年第3期9卷 910-926页

作者： Hariprasad Sampatirao Saikiran Amruthaluru Premchand Chennampalli rama krishna lingamaneni Rameshbabu Nagumothu Department of Metallurgical and Materials Engineering National Institute of TechnologyTiruchirappalli 620015India Centre for Engineered Coatings International Advanced Research Centre for Powder Metallurgy and New Materials(ARCI)Hyderabad 500005India

Zirconia(ZrO_2)incorporated ceramic coatings were fabricated on biodegradable ZM21 Mg alloy by the PEO coupled with EPD ***,the sample surface was modified by laser texturing to improve the corrosion resistance,roughness and cell proliferation and growth *** corrosion performance of the fabricated samples along with the substrate was studied by electrochemical measurements under simulated body fluid(SBF)*** cell direct contact assay was conducted for the substrate and fabricated samples using l-929 mouse fibroblast cells for 24 *** phase contrast images of cell direct contact assay revealed that fabricated samples exhibited better contact and response with the fibroblast cells,compared to the *** addition of nanoparticles in the PEO process,called PEO coupled EPD process,resulted in attaining a higher thickness and improved corrosion performance of the samples than the PEO coated *** all the samples,laser surface textured PEO,and PEO-EPD coated samples unveiled enhanced corrosion resistance,cell growth,thereby enabling it as a suitable prototype for biodegradable implant applications.

关键词： ZM21 ZrO_(2)nanoparticle PEO-EPD laser texturing Corrosion resistance l-929 cells

Review Article on Condition Assessment of Structures Using Electro-Mechanical Impedance Technique

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Structural Durability & Health Monitoring 2022年第2期16卷 97-128页

作者： krishna Kumar Maurya Anupam Rawat rama Shanker Department of Civil Engineering MNNIT AllahabadPrayagraj211004India

Structural health monitoring(SHM)is a process for determination of presence,location,severity of damages and remaining life of the *** is widely applied in aerospace,mechanical and civil engineering sys-tems to assess the conditions of structures to improve the operation,safety,serviceability and reliability,*** are various SHM techniques for monitoring the health of structures such as global response based and local *** occur in the structures due to its inability to withstand intended design loadings,physical environment and chemical ***,damage identification is necessary to improve the durability of the structures for protection against catastrophic *** research paper is focused on elec-tro-mechanical impedance(EMI)technique which is one of the techniques based on smart *** smart materials are utilized for monitoring the health of the *** are used for damage determination and its quantification for the interrogated *** in admittance or impedance signature shows the existence of damage in the ***,the different statistical methods viz.,root mean square deviation(RMSD),mean absolute percentage deviation(MAPD),covariance(Cov),and correlation coefficient(CC)are used for the quantification of *** material such as piezoelectric materials,its properties and applica-tions are also *** this paper,the implementation of EMI technique based on different recent advances in smart materials and their appropriateness have been ***,the reviewed investigations are significant for the monitoring of real-life *** presented paper is the compact state-of-the-art for EMI technique which is used for *** examination will be valuable to infrastructural health monitoring and engineering applications in respect to innovative research directions.

关键词： Structural health monitoring condition assessment EMI technique PZT patches damages

ETP-AKEP: enhanced three-party authenticated key exchange protocols for data integrity in cloud environments

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Journal of Control and Decision 2023年第1期10卷 126-133页

作者： Kalluri rama krishna C.V.Guru Rao Faculty of Informatics Osmania UniversityHyderabadIndia School of Computer Science&Artificial Intelligence S.R.UniversityWarangalIndia

With key exchange protocols, a secure session key is generated between two remote users, andservers and exchanged between them. It is generally used to prevent unauthorised users fromgaining access to sensitive data. This article presents an enhanced three-party authenticated keyexchange protocols (ETP-AKE) protocol that does not depend on symmetric key encryption andinstead uses asymmetric key encryption. A key component of the proposed ETP-AKE protocol isusing elliptic curve encryption in conjunction with a one-way hash function. Its integrity certificationwas confirmed via the usage of the AVISPA tool package. Our proposed protocol is intendedto protect against various security threats, including the man-in-the-middle assault, the parallelattack, and the key-compromise attack, among others.

关键词： ECC hash function cloud integrity third party key exchange

Electrospun CNT embedded ZnO nanofiber based biosensor for electrochemical detection of Atrazine: a step closure to single molecule detection

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Microsystems & Nanoengineering 2020年第1期6卷 1353-1362页

作者： Patta Supraja Vikrant Singh Siva rama krishna Vanjari Shiv Govind Singh Department of Electrical Engineering Indian Institute of TechnologyHyderabadTelangana 502285India School of Medicine University of California DavisDavisCaliforniaUSA

In this study we have reported the design and development of a facile,sensitive,selective,and label-free electrochemical sensing platform for the detection of atrazine based on MWCNT-embedded ZnO *** nanofibers were characterized using scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),X-ray photoelectron spectroscope(XPS),UV-Visible spectroscope(UV-VIS),and Fourier-transform infrared spectroscope(FTIR).Electrochemical properties of MWCNT-ZnO nanofiber-modified electrodes were assessed using electrochemical impedance spectroscopy(EIS)and cyclic voltammetry(CV).Binding event of atrazine to anti-atrazine antibody,which immobilized on nanofiber-modified electrode via EDC and NHS chemistry,was transduced with *** to high conductivity,surface area,and low bandgap of MWCNT-ZnO nanofibers,we have achieved the sensitivity and limit of detection(loD)of sensor as 21.61(KΩμg^(−1) ml^(−1))cm^(−2) and 5.368zM for a wide detection range of 10 zM–1µ*** proposed immunosensing platform has good stability,selectivity,repeatability,and reproducibility,and are less prone to interference.

关键词： fiber fibers closure

Characterization of Mullite-Zirconia Composite Processed by Non-Transferred and Transferred Arc Plasma

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Plasma Science and Technology 2009年第2期11卷 200-205页

作者： S.YUGESWARAN V.SElVARAJAN l.lUSVARGHI A.I.Y.TOK D.SIVA rama krishna Plasma Physics laboratory Department of PhysicsBharathiar University Department of Materials and Environmental Engineering University of Modena e Reggio Emilia School of Materials Science & Engineering Nanyang Technological University

The arc plasma melting technique is a simple method to synthesize high temperature reaction composites. In this study, mullite-zirconia composite was synthesized by transferred and non-transferred arc plasma melting, and the results were compared. A mixture of alumina and zircon powders with a mole ratio of 3 ： 2 were ball milled for four hours and melted for two minutes in the transferred and non-transferred mode of plasma arcs. Argon and air were used as plasma forming gases. The phase and microstruetural formation of melted samples were investigated by X-ray diffraction （XRD） and scanning electron microscope （SEM）. The microstructure of the composites was found to be affected by the mode of melting. In transferred arc melting, zirconia flowers with uniform lines along with mullite whiskers were obtained. In the ease of non-transferred are plasma melting, mullite whiskers along with star shape zirconia were formed. Differential thermal analysis （DTA） of the synthesized mullite-zirconia composites provided a deeper understanding of the mechanisms of mullite formation during the two different processes.

关键词： arc plasma melting composites