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Low velocity impact studies of e-glass/epoxy composite laminates at different thicknesses and temperatures

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Defence Technology（防务技术） 2019年第6期15卷 897-904页

作者： T.Sreekantha reddy p.Rama Subba reddy Vemuri Madhu Defence Metallurgical Research Laboratory

Low velocity impact experiments were carried out on e-glass/epoxy composite laminates having varying thicknesses at sub zero and elevated temperatures using hemi spherical steel impactor of 16 mm diameter with impact energies in the rage of 50-150 *** performance of the laminates was assessed in terms of energy absorption,maximum displacement,peak force and failure *** indicated that the effect of temperature on energy absorption of the laminate is negligible although the laminates are embrittling at sub zero *** it has influence on failure behaviour and *** force has increased linearly with increase in laminate thickness from 5 to 10 *** it got reduced by 25% when temperature was increased from-20℃ to 100℃,Based on experimental results,laminate perforation energies were predicted using curve fitting *** analysis was carried out using Taguchi method to identify the global effects of various parameters on laminate performance and confirmed that the laminate thickness has significant influence as compared to temperature,for the studied range.

关键词： Laminates Glass fibres Impact behaviour Delamination

Grid Voltage Sensor-less protection Scheme for One Cycle-Controlled Single-phase photovoltaic Inverter Systems

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CSee Journal of power and energy Systems 2022年第6期8卷 1720-1729页

作者： Venkata R.reddy Sreeraj e.S. are with National Institute of Technology Goa Farmagudi Ponda 403401India

One-cycle-controlled(OCC)inverters are suitable for small single-phase photovoltaic distributed-generator systems because of their simplicity,phase-locked-loop free structure,grid voltage sensor-less operation,and *** voltage sensor-less control helps reduce cost and increases reliability in *** various sensors are used for implementation of a protection *** this paper,a grid voltage sensorless protection scheme for OCC based single-phase inverter systems is *** estimated value of voltage at point of common coupling(VpCC)is used for protecting the system during over/under voltage conditions of the grid,implementing of voltage ride through conditions,and for disconnecting the grid during islanded *** VpCC is estimated from the measured inverter current,switching pulses,and the measured dc-link voltage using a second-order *** and experimental studies are performed to verify the efficacy of the proposed voltage sensor-less protection mechanism triggered using estimated VpCC.

关键词： One cycle control photovoltaic systems voltage sensorless voltage protection over/under voltage protection islanding detection

process parameters-weld bead geometry interactions and their influence on mechanical properties:A case of dissimilar aluminium alloy electron beam welds

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Defence Technology（防务技术） 2018年第2期14卷 137-150页

作者： p.Mastanaiah Abhay Sharma G.Madhusudhan reddy Defence Research and Development Laboratory KanchanbaghHyderabadTelangana 500058India Indian Institute of Technology Hyderabad Kandi CampusSangareddyTelangana 502285India Defence Metallurgical Research Laboratory KanchanbaghHyderabadTelangana 500058India

prediction of weld bead geometry is always an interesting and challenging research topic as it involves understanding of complex multi input and multi output system. The weld bead geometry has a profound impact on the load bearing capability of a weld joint, which in-turn decides the performance in real time service conditions. The present study introduces a novel approach of detecting a relationship between weld bead geometry and mechanical properties(e.g. tensile load) for the purpose of catering the best the process could offer. The significance of the proposed approach is demonstrated by a case of dissimilar aluminium alloy(AA2219 and AA5083) electron beam welds. A mathematical model of tensile braking load as a function of geometrical attributes of weld bead geometry is presented. The results of investigation suggests the effective thickness of weld-a geometric parameter of weld bead has the most significant influence on tensile breaking load of dissimilar weld joint. The observations on bead geometry and the mechanical properties(microhardness, ultimate tensile load and face bend angle) are correlated with detailed metallurgical analysis. The fusion zone of dissimilar electron beam weld has finer grain size with a moderate evaporation and segregation of alloying elements magnesium and copper *** mechanical properties of weld joint are controlled by optimum bead geometry and HAZ softening in weaker AA5083 Al alloy.

关键词： electron beam welding AA2219 AA5083 Bead geometry Tensile breaking load

Near-Net-Shaped Objects of Re123 Superconductors byInfiltration processing

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Tsinghua Science and Technology 2003年第3期8卷 292-306页

作者： e.S.reddy G.J.Schmitz ACCeSS Materials and processes D-52056 AachenGermanyACCESS Materials and ProcessesD-52056 AachenGermany

The fabrication of near-net-shaped objects of Re123 superconductors by 'infiltration processing' is discussed. Near-net-shape processing involves the infiltration of preshaped porous green bodies of either 211 or yttria phases by liquids containing barium cuprates and copper oxides followed by a controlled peritectic solidification. The process yields poly- and also single-crystalline superconducting objects with a shrinkage of less than half of one percent of the green bodies. The preservation of the initial structure of the green bodies results in fabrication of Re 123 in a wide variety of dimensions and complex shapes. The demonstrated products include bulk components like cylinders, single domain thick films on a variety of substrates, freestanding fabrics and open porous superconducting foams. This paper presents a comprehensive description of the infiltration processing technique and the resulting microstructures of the superconducting bodies. The advantages of this technique and practical applications of the processed superconducting structures are highlighted.

关键词： infiltration processing near-net shape shaping joining single domain crystal growth thick films foams applications

HSRDN: High-Speed Router Design for Various No C Topologies

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Chinese Journal of electronics 2020年第2期29卷 281-290页

作者： e.Lakshmi prasad M.N.Giri prasad A.R.reddy Department of eCe JNTUACE Department of RRC MITS

High-speed router design for network on chip(HSRDN) is proposed for controlling the traffic congestion and deadlocks. Diagonal based nearest-path routing algorithm for No C(DNRAN) can mitigate the effect of latency by opting for the nearest-path to reach the destination in a network and HSRDN is part of DNRAN. When we analyze the performance of DNRAN for all proposed topologies, nearly 50% better in terms of latency reduction and high throughput over existing router architectures. The proposed topologies(2 D-mesh,2 D-Star mesh over regional mesh(SMo RM), 3 D-mesh,and 3 D-torus) are tested with various applications, viz,audio, video and so on. Here, we also tested with cryptography application for DNRAN. When we analyzed the performance of experimental results, exclusively in 2 D-SMo RM nearly 0.6 times latency get reduced, area expanded by 0.25 and 0.33 times throughput increase in 2 D-SMo RM compared with 3 D-mesh and 3 ***, DNRAN showed an exclusive performance in 2 D-SMo RM compared with other two topologies.

关键词： Logic Network on chip(NoC) Virtual channels Latency Congestion Shortest path routing algorithm 3D-mesh 3D-torus

expeditious method for the synthesis of novel 2,3,5,6-tetrahydrobenzo[g] [1,3,5]oxadiazocine-4-thiones linked with isoxazole

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Chinese Chemical Letters 2008年第12期19卷 1415-1418页

作者： e.Rajanarendar A.Siva Rami reddy M.Srinivas Department of Chemistry Kakatiya UniversityWarangal 506009India

Synthesis of novel 3-aryl-5-（3,5-dimethylisoxazol-4-yl）-2,3,5,6-tetrahydrobenzo[g][1,3,5],oxadiazocine-4-thiones 5 has been accomplished from 3,5-dimethylisoxazol-4-amine 1 by condensation with salicylaldehydes, followed by reduction, treatment with aryl isothiocyanates and subsequent smooth ring closure via acetal formation in the presence of formaldehyde.

关键词： Isoxazolyl-2,3,5,6-tetrahydrobenzo[g]oxadiazocine-4-thiones Ring closure New methodology

5-Fluorouracil Loaded Chitosan–pVA/Na^+MMT Nanocomposite Films for Drug Release and Antimicrobial Activity

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Nano-Micro Letters 2016年第3期8卷 260-269页

作者： A.Babul reddy B.Manjula T.Jayaramudu e.R.Sadiku p.Anand Babu S.periyar Selvam Department of Chemical Metallurgical and Materials Engineering Tshwane University of Technology CSIR Campus Department of Food process engineering School of Bioengineering SRM University

In the present study, chitosan and polyvinyl alcohol(pVA) were blended with different concentrations of sodium montmorillonite(Na^+MMT) clay solution by a solvent casting method. X-ray diffraction and transition electron microscope results show that the film properties are related to the co-existence of Na^+MMT intercalation/exfoliation in the blend and the interaction between chitosan–pVA and Na^+MMT. 5-Fluorouracil(5-FU) was loaded with chitosan–pVA/Na^+MMT nanocomposite films for in vitro drug delivery study. The antimicrobial activity of the chitosan–pVA/Na^+MMT films showed significant effect against Salmonella(Gram-negative) and Staphylococcus aureus(Gram-positive), whereas5-FU encapsulated chitosan–pVA/Na^+MMT bio-nanocomposite films did not show any inhibition against bacteria. Our results indicate that combination of a flexible and soft polymeric material with high drug loading ability of a hard inorganic porous material can produce improved control over degradation and drug release. It will be an economically viable method for preparation of advanced drug delivery vehicles and biodegradable implants or scaffolds.

关键词： Biopolymer Chitosan–pVA/Na+MMT Montmorillonite 5-Fluorouracil Drug release Antimicrobial activity

Camphor-derived thioureas: Synthesis and application in asymmetric Kabachnik-Fields reaction

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Chinese Chemical Letters 2016年第6期27卷 943-947页

作者： pogula Sreekanth reddy Motakatla Venkata Krishna reddy peddiahgari Vasu Govardhana reddy Department of Chemistry Yogi Vemana University

A series of camphor-derived thiourea organocatalysts 3a–f were designed and synthesized from（1R,3S）-camphoric acid 1 and applied to the one-pot three-component Kabachnik–Fields reaction. Catalyst 3c was found to be an efficient organocatalyst for the reaction of 2-cyclopropylpyrimidin-4-carbaldehyde 4,various amines 5, and diphenylphosphite 6 to yield the corresponding enantioselective a-aminophosphonates 7a–e in 74%–82% yields and 14%–35% ee.

关键词： Asymmetric organocatalysis (1R 3S)-Camphoric acid Camphor-derived thioureas Chiral a-aminophosphonates enantioselective Kabachnik-Fields reaction

Multi-component synthesis of methylene bis isoxazolo[4,5-b]-pyridine-N-oxides

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Chinese Chemical Letters 2010年第8期21卷 927-930页

作者： e.Rajanarendar M.Nagi reddy K.Rama Murthy Department of Chemistry Kakatiya University

A three component one-pot protocol was investigated for the synthesis of methylene bis isoxazolo[4,5-b]-pyridine-N-oxides from commercially available materials.

关键词： Multi-component synthesis Knoevenagel condensation Michael addition New methodology