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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

Additive manufacturing of biodegradable magnesium-based materials:Design strategies,properties,and biomedical applications

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Journal of Magnesium and Alloys 2023年第3期11卷 801-839页

作者： Farzad Badkoobeh Hossein Mostaan Mahdi Rafiei Hamid Reza Bakhsheshi-Rad Seeram rama krishna Xiongbiao Chen School of Metallurgy and Materials Engineering College of EngineeringUniversity of TehranTehranIran Faculty of Engineering Department of Materials and Metallurgical EngineeringArak UniversityArakIran Advanced Materials Research Center Department of Materials EngineeringNajafabad BranchIslamic Azad UniversityNajafabadIran Department of Mechanical Engineering National University of Singapore9 Engineering Drive 1Singapore 117576Singapore Department of Mechanical Engineering College of EngineeringUniversity of SaskatchewanSaskatoonSK S7N 5A9Canada

Magnesium(Mg)-based materials are a new generation of alloys with the exclusive ability to be biodegradable within the human/animal *** addition to biodegradability,their inherent biocompatibility and similar-to-bone density make Mg-based alloys good candidates for fabricating surgical bioimplants for use in orthopedic and traumatology *** this end,nowadays additive manufacturing(AM)along with three-dimensional(3D)printing represents a promising manufacturing technique as it allows for the integration of bioimplant design and manufacturing processes specific to given ***,this technique also faces many new challenges associated with the properties of Mg-based alloys,including high chemical reactivity,potential for combustion,and low vaporization *** this review article,various AM processes to fabricate biomedical implants from Mg-based alloys,along with their metallic microstructure,mechanical properties,biodegradability,biocompatibility,and antibacterial properties,as well as various post-AM treatments were critically ***,the challenges and issues involved in AM processes from the perspectives of bioimplant design,properties,and applications were identified;the possibilities and potential scope of the Mg-based scaffolds/implants are discussed and highlighted.

关键词： Magnesium alloy Additive manufacturing 3D Printing Bone tissue engineering Scaffold Mechanical and biological properties

Hydro-elastic computational analysis of a marine propeller using two-way fluid structure interaction

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Journal of Ocean Engineering and Science 2022年第3期7卷 280-291页

作者： V.rama krishna Srinivas Prasad Sanaka N.Pardhasaradhi B.Raghava Rao Naval Science&Technological Laboratory Visakhapatnam532007India Department of Mechanical Engineering V.R.Siddhartha Engineering CollegeVijayawada520007India

Marine propellers have complex geometry and their performance is determined by costly and time consuming open water *** of numerical techniques helps researchers in effective design of *** approaches are used that predicted either hydrodynamic and acoustic response or structural ***-way fluid-structure interaction(FSI)analysis is a very useful approach providing all three responses which helps in the design,analysis and optimization of a *** objective of this paper is to predict the hydro-elastic response of a propeller using two-way FSI on a 0.2m diameter,DTMB-4119 propeller using ANSYS ***-way FSI analysis is carried out using system coupling approach that transfers the data between the structural and fluid *** turbulence effects are captured using the large-eddy simulation(LES)model and the Ffowcs Williams Hawkings(FWH)acoustic model is used for evaluating the sound pressure level(SPL)generated by *** is extended to evaluate the hydro-elastic and acoustic response of the propeller after validating the hydrodynamic performance with the experimental result in the *** results from Two-way FSI analysis are in close agreement when compared with the one-way FSI ***-way FSI can accommodate the peak value of stress and deformation developed during the initial part of the transient solution which is important in the design of *** study reveals that metallic(NAB)propeller can be replaced by a composite *** acoustic response from two-way FSI analysis will be more realistic due to the consideration of hydro-elastic effect of propeller.

关键词： Advance ratio Coupled analysis CFD Marine propeller Hydrodynamic parameters Two-way fluid structure interaction

Structural,electrical and magnetic properties of cobalt ferrite with Nd^(3+) doping

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Rare Metals 2022年第1期41卷 240-245页

作者： Regaty Anitha Reddy Kattepogu rama Rao Bitra Rajesh Babu Guthikonda Kiran Kumar Cherukupalli Rajesh Anindita Chatterjee Nadella krishna Jyothi Department of Physics Koneru Lakshmaiah Education FoundationVaddeswaramGunturAndhra Pradesh 522502India Department of Physics Andhra UniversityVisakhapatnamAndhra Pradesh 530003India Department of Physics G.V.P.College of Engineering for WomenVisakhapatnamAndhra Pradesh 530048India Department of Physics Raghu College of Engineering(A)BheemunipatnamVisakhapatnamAndhra Pradesh 531162India Department of Physics Gayatri Vidya Parishad College of Engineering(Autonomous)VisakhapatnamAndhra Pradesh 530048India Department of Chemistry Raghu College of Engineering(A)BheemunipatnamVisakhapatnamAndhra Pradesh 531162India

A systematic study on the influence of Nd^(3+) substitution on structural,magnetic and electrical properties of cobalt ferrite nanopowders obtained by sol–gel auto-combustion routewas *** formation of spinel phasewas confirmed by X-ray diffraction(XRD)data,and percolation limit ofNd3?into the spinel lattice was also *** transform infrared spectroscopy(FTIR)bands observed ≈580 and ≈390 cm^(-1 ) support the presence of Fe^(3+) at A andBsites in the spinel *** variation in microstructure was investigated by scanning electronmicroscopy(SEM),and the average grain size varies from 5.3 to 3.3 *** substitution of Nd^(3+) significantly affects the formation of pores and grain size of cobalt ***-temperature saturation magnetization and coercivity decrease from 60 to 30 mA·m^(2)·g^(-1) and 19.9–17.8 mT,respectively,with Nd^(3+) substitution *** decreases in magnetic properties are explained based on the presence of non-magnetic nature of Nd^(3+) concentration and the dilution of super-exchange interaction in the spinel *** room-temperature direct-current electrical resistivity increases with Nd^(3+) concentration increasing,which is due to the unavailability of Fe^(2+) at octahedral B sites.

关键词： Co-Nd ferrite Saturation magnetization DC resistivity

A silver-catalyzed[3+3]-annulation cascade of alkynyl alcohols andα,β-unsaturated ketones for the regioselective assembly of chromanes

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Organic Chemistry Frontiers 2022年第3期9卷 802-809页

作者： Ashwini K.Nakate Sagar S.Thorat Shailja Jain Gamidi rama krishna Kumar Vanka Ravindar Kontham Organic Chemistry Division CSIR-National Chemical LaboratoryDr Homi Bhabha RoadPune-411008India Academy of Scientific and Innovative Research(AcSIR) Ghaziabad-201002India Centre for Materials Characterization CSIR-National Chemical LaboratoryDr Homi Bhabha RoadPune-411008India Physical and Materials Chemistry Division CSIR-National Chemical LaboratoryDr Homi Bhabha RoadPune-411008India

An unprecedented Ag(I)-catalyzed[3+3]-annulation of alkynyl alcohols(5-hexyn-1-ols)andα,β-unsaturated ketones is reported to construct simple to complex *** transformation begins with hydroalkoxylation of alkynol through C-C triple bond activation to give cyclic-enol ether,followed by intermolecular 1,4-addition and intramolecular 1,2-addition of enol ethers onto the enone and oxidative aromatization or Grob-type elimination steps.

关键词： alcohols unsaturated catalyzed

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

Fabrication and Characterisation of Rutile-TiO_2 Coatings on Metallic Alloy Substrates

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材料热处理学报 2004年第5B期25卷 862-865页

作者： D. Siva rama krishna School of Materials Engineering Nanyang Technological University Singapore 639798

In the present work, attempts have been made to extend the use of the tribological and chemical properties of rutile-TiO2 to metallic alloy systems, by forming a rutile coating on the metallic substrates. Two metallic alloys were selected in this study, including AISI316L austenitic stainless steel and aluminium alloy. The rutile-based coatings were fabricated by magnetron sputter deposition of a pure titanium coating first, and then thermal oxidation of the coated specimens to partially convert the titanium coating to rutile oxide and to promote interfacial reactions which can significantly enhance the coating-substrate adhesion strength. The structures and properties of the coating-substrate systems were characterized by a variety of analytical and experimental techniques, including X-ray diffraction, glow discharge spectrometry, high resolution SEM, nanoindentation, microscratch, friction and wear testing, as well as electrochemical testing. The results show that the friction and wear properties, as well as the corrosion resistance of the metallic alloys can be significant enhanced by surface engineering with rutile-TiO2.

关键词：金红石二氧化钛不锈钢磨损性能耐蚀性

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)