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Microstructure and corrosion behaviour of gas tungsten arc welds of maraging steel

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Defence Technology（防务技术） 2015年第1期11卷 48-55页

作者： G.MADHUSUDHAN reddy k.SRINIVASA RAO Defence Metallurgical Research Laboratory Department of Metallurgical Engineering Andhra University

Superior properties of maraging steels mak. them suitable for the fabrication of components used for military applications lik. missile covering, rock.t motor casing and ship hulls. Welding is the main process for fabrication of these components, while the maraging steels can be fusion welded using gas tungsten arc welding(GTAW) process. All these fabricated components require longer storage life and a major problem in welds is susceptible to stress corrosion crack.ng(SCC). The present study is aimed at studying the SCC behaviour of MDN 250(18% Ni) steel and its welds with respect to microstructural changes. In the present study, 5.2 mm thick.sheets made of MDN 250 steel in the solution annealed condition was welded using GTAW process. Post-weld heat treatments of direct ageing(480 C for 3 h), solutionizing(815 C for 1 h) followed by ageing and homogenizing(1150 C for 1 h) followed by ageing were carried out. A mixture of martensite and austenite was observed in the microstructure of the fusion zone of solutionized and direct aged welds and only martensite in as-welded condition. Homogenization and ageing treatment have eliminated reverted austenite and elemental segregation. Homogenized welds also exhibited a marginal improvement in the corrosion resistance compared to those in the as-welded, solutionized and aged condition. Constant load SCC test data clearly revealed that the failure time of homogenized weld is much longer compared to other post weld treatments, and the homogenization treatment is recommended to improve the SCC life of GTA welds of MDN 250 Maraging steel.

关键词： 18% Ni maraging steel Gas tungsten arc welding Post weld heat treatment Solutionising Ageing treatment Pitting corrosion Stress corrosioncrack.ng (SCC)

Spectral change and far-red emission of Mn^(2+)ions co-doped NaSrB_(5)O_(9):Dy^(3+)luminescence material for plant growth LEDs

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Journal of Rare Earths 2022年第2期40卷 218-225,I0002页

作者： k.Munirathnam k.duru Mallik.rjuna R.Vijaya P.C.Nagajyothi k.Ramak.ishna reddy M.Srinivas Department of Physics School of Applied SciencesREVA UniversityBengaluru560064India Department for Management of Science and Technology Development Ton Due Thang UniversityHo Chi Minh CityVietnam Faculty of Applied Sciences Ton Due Thang UniversityHo Chi Minh CityVietnam Department of Physics Visvodaya Government Degree CollegeVenkatagiri524132India School of Mechanical Engineering Yeungnam UniversityGyeongsan33541South Korea Department of Chemistry School of Applied SciencesREVA UniversityBengaluru560064India

Due to the characteristic emission of phosphors,phosphor-converted LEDs have been employed to provide the requisite light sources for indoor plant growth in the optical agricultural ***,we prepared a series of Mn^(2+)co-doped NaSrB5 O9:Dy^(3+)phosphors via a solid-state reaction *** phosphors have significant three-band emissions at 467 nm(blue region),606 nm(orange region),and765 nm(far-red region),ascribed to the^(4)F_(9/2)-^(6)H_(15/2)and 4 F9/2-6 H13/2 transitions of the Dy^(3+)ions and the^(4)T_(1g)(G)-^(6)A_(1g)(S)spin-forbidden transition of the Mn^(2+)ions,respectively,when excited by light of 376 nm(near-UV region).The co-dopant in the host material facilitates tunable photoluminescence(PL)due to energy transfer from the Dy^(3+)ions to the Mn^(2+)*** three emission peak. from the prepared phosphors well match with the absorption spectra of the photosynthesis pigments of plants,chlorophyll and phytochrome,which can absorb blue(400-500 nm),orange-red(550-700 nm),and infrared(IR)radiation,indicating that these phosphors have potential applications in the fabrication of plant-growth *** to the PL studies,the structure of the phosphors was determined by X-ray diffraction,refined by Rietveld method and chemically quantified by X-ray photoelectron spectroscopy.

关键词： Phosphors Refinement X-ray photoelectron spectroscopy Energy transfer Plant growth LEDs Rare earths

Distributed resource scheduling in smart grid with electric vehicle deployment using firework. algorithm

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Journal of Modern Power Systems and Clean Energy 2016年第2期4卷 188-199页

作者： k.Srik.nth reddy Lok.sh k.mar PANWAR Rajesh k.MAR Bijaya k.tan PANIGRAHI IIT Delhi New DelhiIndia MNIT Jaipur JaipurRajasthanIndia

Global warming and climate change are two k.y probing issues in the present *** electricity sector and transportation sector are two principle entities propelling both these *** from these two sectors can be offset by switching to greener ways of transportation through the electric vehicle (EV) and renewable energy technologies (RET).Thus,effective scheduling of both resources holds the k.y to sustainable *** paper presents a scheduling scenario-based approach in the smart *** formulation with dual objective function including both emissions and cost is developed for conventional unit commitment with EV and RET *** this work.the scheduling and commitment problem is solved using the firework. algorithm which mimics explosion of firework. in the sk. to define search space and the distance between associated spark. to evaluate global ***,binary coded firework. algorithm is developed for the proposed scheduling problem in the smart ***,possible scenarios inconventional as well as smart grid are put *** that,the proposed methodology is simulated using a test system with thermal generators.

关键词： Unit commitment problem(UCP) Binary firework. algorithm(BFWA) Constrained optimization Renewable energy technologies(RETs) Plug-in electric vehicle(PEV)

Mathematical modelling of couple stresses on fluid flow in constricted tapered artery in presence of slip velocity-effects of catheter

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Applied Mathematics and Mechanics(English Edition) 2014年第8期35卷 947-958页

作者： J.V.R.reddy D.SRIk.NTH S.k.MURTHY Department of Applied Mathematics Defence Institute of Advanced Technology Deemed UniversityPune 411025MaharastraIndia

This paper explores the mathematical model for couple stress fluid flow through an annular region. The above model is used for studying the blood flow be-tween the clogged （stenotic） artery and the catheter. The asymmetric nature of the stenosis is considered. The closed form expressions for the physiological parameters such as impedance and shear stress at the wall are obtained. The effects of various geomet-ric parameters and the parameters arising out of the fluid considered are discussed by considering the slip velocity and tapering angle. The study of the above model is very significant as it has direct applications in the treatment of cardiovascular diseases.

关键词： blood flow couple stress fluid stenosed artery tapered artery catheter

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 k.oevenagel condensation Michael addition New methodology

Deep-Sea Benthic Foraminiferal Distribution in South West Indian Ocean: Implications to Paleoecology

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International Journal of Geosciences 2010年第2期1卷 79-86页

作者： Nadimik.ri Jayaraju Balam Chinnapolla Sundara raja reddy k.mbham Reddeppa reddy Addula Nallappa reddy 不详

Five grab samples from the southwestern part of the Indian ocean were collected by ORV Sagar k.nya during the third expedition to the southern Indian ocean in June 2009. The sediment samples have been analyzed and recorded 36 benthic foraminiferal species belonging to 21 genera and 3 suborders. All the species were taxonomically identified, SEM photographed and illustrated. Deep sea-benthic foraminiferal species at different locations of South of West India Ocean (3150-4125 m water depth) is examined in terms of number of species (n) and diversity (d). The observed depth ranges of benthic foraminifera have been documented to recognize their bathymetric distribution. The valves of these parameters reached their maximum at 3190 m water depth. Productivity continued in the Indo-Pacific Ocean (the biogenic boom) and the Oxygen minimum zone (OMZ) intensified over large parts of Indian Ocean continually. The diversity values show more abrupt trend as depth increases. Species lik. Epistominella exigua and Pullenia bulloides occur at both 3150 m & 3465 m depths indicating depth persistence. Further, Oridorsalis umbonatus and Melonis sphaeroides occur at both 3150 m & 3465 m depths. Species lik. Gyroidina sp an indicate of low oxygen environment and Uvigerina hispida-costata indicative of high organic carbon are found to occur at 3150 m & 3740 m respectively. Factor analysis and Pearson correlation matrix was performed on foraminiferal census data of 10 highest rank.d species which are present in at least one sample. 3 factors were obtained accounting for 72.81% of the total variance. Thus the study suggests that fluctuations in species diversity at the locations of the present study were related to changes in productivity during the geological past. Further, the faunal data do indicate the early Holocene Indian Ocean was influenced by increased ventilation perhaps by North Atlantic deep water and or circumpolar deep waters.

关键词： Paleoecology Benthicforaminifera Holocene Indian Ocean

Propylphosphonic anhydride(T3P~) catalyzed one-pot synthesis of α-aminonitriles

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Chinese Chemical Letters 2015年第6期26卷 739-743页

作者： Sirigireddy Sudharsan reddy Bhoomireddy Rajendra Prasad reddy Peddiahgari Vasu Govardhana reddy Department of Chemistry Yogi Vemana University

The Streck.r reaction was performed via a one-pot three component condensation of hetero aromatic/ aromatic aldehydes, secondary amines and trimetylsilyl cyanide in the presence of propylphosphonic anhydride （T3P） to accomplish the corresponding α-aminonitriles. The main advantages of this method are very short reaction time and excellent yields.

关键词： Streck.r reaction α-Aminonitriles Propylphosphonic anhydride5-Fluoro-3-methyl-2-carbaldehyde

Integrated water vapor during active and break.spells of monsoon and its relationship with temperature,precipitation and precipitation efficiency over a tropical site

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Geodesy and Geodynamics 2022年第3期13卷 238-246页

作者： Nirmala Bai Jadala Miriyala Sridhar Gopa Dutta Mohammed Yousuf Y.k.reddy Department of ECE Koneru Lakshmaiah Education FoundationVaddeswaramGuntur Dt522502A.PIndia Vignana Bharathi Institute of Technology GhatkesarMedchal DtTelangana501301India India Meteorological Department HyderabadTelangana500016India

Global Positioning System(GPS)measurements of integrated water vapor(IWV)for two years(2014 and 2015)are presented in this *** of IWV during active and break.spells of Indian summer monsoon has been studied for a tropical station Hyderabad(17.4°N,78.46°E).The data is validated with ECMWF Re-Analysis(ERA)91 level *** of IWV with other atmospheric variables lik. surface temperature,rain,and precipitation efficiency have been established through cross-correlation studies.A positive correlation coefficient is observed between IWV and surface temperature over two *** the coefficient becomes negative when only summer monsoon months(June,July,August,and September)are *** during these months cools down the surface and could be the reason for this change in the correlation *** studies between IWV-precipitation,IWVprecipitation efficiency(P.E),and precipitation-P.E show that coefficients are-0.05,-0.10 and 0.983 with 95%confidence level respectively,which proves that the efficacy of rain does not depend only on the level of water vapor.A proper dynamic mechanism is necessary to convert water vapor into the *** diurnal variations of IWV during active and break.spells have been *** amplitudes of diurnal oscillation and its harmonics of individual spell do not show clear trends but the mean amplitudes of the break.spells are approximately double than those of the active *** amplitudes of diurnal,semidiurnal and ter-diurnal components during break.spells are 1.08 k./m^(2),0.52 k./m;and 0.34 k./m;*** corresponding amplitudes during active spells are 0.68 k./m^(2),0.41 k./m;and 0.23 k./m;.

关键词： Precipitation efficiency Diurnal oscillation Integrated water vapor Tropical site Break.spells of monsoon Active spells of monsoon

Camphor-derived thioureas: Synthesis and application in asymmetric k.bachnik.Fields reaction

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

作者： Pogula Sreek.nth reddy Motak.tla Venk.ta k.ishna 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 k.bachnik.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 k.bachnik.Fields reaction