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Nanoscale resetting of the Th/Pb system in an isotopically-closed monazite grain: A combined atom probe and transmission electron microscopy study

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Geoscience Frontiers 2019年第1期10卷 65-76页

作者： A.-m.seydoux-Guillaume D.Fougerouse A.T.Laurent E.Gardés s.m.reddy D.W.saxey Univ Lyon UJM-Saint-Etienne CNRS IRD CNRs Université Clermont Auvergne school of Earth and Planetary sciences Curtin University Geoscience Atom Probe Advanced Resource Characterisation Facility John de Laeter Centre Curtin University Centre de recherche sur les Ions les Matériaux et la Photonique (CIMAP) Department of Physics and Astronomy Curtin University

Understanding the mechanisms of parent-daughter isotopic mobility at the nanoscale is key to rigorous interpretation of Ue The Pb data and associated dating. Until now, all nanoscale geochronological studies on geological samples have relied on either Transmission Electron microscope(TEm) or Atom Probe microscopy(APm) characterizations alone, thus suffering from the respective weaknesses of each technique. Here we focus on monazite crystals from a ~1 Ga, ultrahigh temperature granulite from Rogaland(Norway). This sample has recorded concordant UeP b dates(measured by LA-ICP-ms) that range over 100 my, with the three domains yielding distinct isotopic Ue Pb ages of 1034 ± 6 ma(D1; srich core), 1005 ± 7 ma(D2), and 935 ± 7 ma(D3), respectively. Combined APm and TEm characterization of these monazite crystals reveal phase separation that led to the isolation of two different radiogenic Pb(Pb*) reservoirs at the nanoscale. The s-rich core of these monazite crystals contains Cae srich clusters, 5 -10 nm in size, homogenously distributed within the monazite matrix with a mean interparticle distance of 40 -60 nm. The clusters acted as a sink for radiogenic Pb(Pb*) produced in the monazite matrix, which was reset at the nanoscale via Pb diffusion while the grain remained closed at the micro-scale. Compared to the concordant ages given by conventional micro-scale dating of the grain,the apparent nano-scale age of the monazite matrix in between clusters is about 100 myr younger, which compares remarkably well to the duration of the metamorphic event. This study highlights the capabilities of combined APm-TEm nano-structural and nano-isotopic characterizations in dating and timing of geological events, allowing the detection of processes untraceable with conventional dating methods.

关键词： monazite Nanoscale resetting Nano-clusters APm TEm UHT metamorphism

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Zircon geochronology reveals polyphase magmatism and crustal anatexis in the Buchan Block,NE scotland:Implications for the Grampian Orogeny

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Geoscience Frontiers 2017年第6期8卷 1469-1478页

作者： T.E.Johnson C.L.Kirkland D.R.Viete s.Fischer s.m.reddy N.J.Evans B.J.mcDonald Department of Applied Geology The Institute for Geoscience Research(TIGeR)CET-Curtin NodeJohn de Laeter CentreCurtin UniversityPerthWA 6102Australia morton K.Blaustein Department of Earth&Planetary sciences Johns Hopkins UniversityOlin Hall3400 N Charles StreetBaltimoreMD 21218USA school of Earth&Environmental science University of St AndrewsIrvine BuildingNorth StreetSt AndrewsKY16 9ALScotlandUK

The type locality for high-temperature,low-pressure regional metamorphism,the Buchan Block in NE scotland,exhibits profound differences to the rest of the Grampian *** differences have led some to regard the Buchan Block as an exotic crustal fragment comprising Precambrian basement gneisses and cover rocks thrust into their current position during Grampian *** rocks of the Buchan Block are now generally correlated with Dalradian strata elsewhere,the origin of the gneisses and the cause of the high heat flow and associated magmatism is *** report sIms U-Pb and LA-ICPms Hf isotopic data in zircon from high-grade rocks from the northeast(Inzie Head Gneiss)and northwest(Portsoy)corners of the Buchan *** Inzie Head,upper amphibolite to granulite facies metasedimentary gneisses coexist with diorite sheets that were emplaced contemporaneously with partial melting of their host rocks,at least locally.U-Pb geochronology indicates a crystallisation age for the diorite of 486±9 ***-deformed diorites within the Portsoy Gabbro have a crystallisation age of 493±8 *** of ca.490 ma for magmatism and high-grade metamorphism,which are broadly contemporaneous with ophiolite obduction and the onset of orogenesis,are significantly older than the established peak of Grampian metamorphism(ca.470 ma).We propose a new model for the Grampian Orogeny involving punctuated tectonothermal activity due to tectonic switching during accretionary *** of a NW-dipping subduction zone at ca.490 ma produced a back-arc environment(the Buchan Block)with associated arc magmatism and high dT/dP *** of an outboard arc resulted in shortening(the initial phase of the Grampian Orogeny)at ca.488 *** of a NW-dipping subduction zone to the sE of the ca.488 ma suture began at 473 ma and led to lithospheric-scale extension,decompression melting and advective heating of the middle crust,producing the widespread ca.470 ma Gram

关键词： Dalradian Grampian Orogeny Buchan Block Zircon geochronology magmatism metamorphism

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molybdenum disulfide and magnesium oxide nanoparticle performance on micropolar Cattaneo-Christov heat flux model

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Applied mathematics and mechanics(English Edition) 2021年第4期42卷 541-552页

作者： m.G.reddy s.A.sHEHZAD Department of mathematics Acharya Nagarjuna University CampusOngole 523001Andhra PradeshIndia Department of mathematics COMSATS University IslamabadSahiwal 57000Pakistan

This article intends to illustrate the Darcy flow and melting heat transmission in micropolar *** major advantage of micropolar fluid is the liquid particle rotation through an independent kinematic vector named the microrotation *** novel aspects of the Cattaneo-Christov(C-C)heat flux and Joule heating are incorporated in the energy transport *** different nanoparticles,namely,mos2 and mgO,are suspended into the *** governing partial differential equations(PDEs)of the prevailing problem are slackening into ordinary differential expressions(ODEs)via similarity *** resulting mathematical phenomenon is illustrated by the implication of fourth-fifth order Runge-Kutta-Fehlberg(RKF)*** fluid velocity and temperature distributions are deliberated by using graphical phenomena for multiple values of physical *** results are displayed for both molybdenum disulphide and magnesium oxide nanoparticles.A comparative benchmark in the limiting approach is reported for the validation of the present *** is revealed that the incrementing material constraint results in a higher fluid velocity for both molybdenum disulphide and magnesium oxide nanoparticle situations.

关键词： micropolar fluid Cattaneo-Christov(C-C)heat flux molybdenum disulphide nanoparticle melting effect numerical solution

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Pentachlorophenol degradation by Pseudomonas stutzeri CL7 in the secondary sludge of pulp and paper mill

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Journal of Environmental sciences 2010年第10期22卷 1608-1612页

作者： santosh Kr.Karn s.K.Chakrabarty m.s.reddy Department of Biotechnology Thapar University Thapar Centre for Industrial Research and Development

A pentachlorophenol （PCP） mineralizing bacterium was isolated from the secondary sludge of pulp and paper mill and identified as Pseudomonas stutzeri strain CL7. This isolate used PCP as its sole source of carbon and energy and was capable of degrading this compound as indicated by stoichiometric release of chloride and biomass formation. P. stutzeri （CL7） was able to mineralize a high concentration of PCP （600 mg/L） than any previously reported Pseudomonad with PCP as sole carbon source. As the concentration of PCP increased from 50 to 600 mg/L, the reduction in the cell growth was observed and the PCP degradation was more than 90% in all studied concentrations. This isolate was able to remove 66.8% of PCP from the secondary sludge of pulp and paper mill when supplemented with 100 mg/L of PCP and grown for two weeks. This study showed that the removal efficiency of PCP by CL7 was found to be very effective and can be used in PCP remediation of pulp paper mill waste in the environment.

关键词： pentachlorophenol 16s rRNA secondary sludge bioremediation pulp and paper mill

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Influence of Nano-materials on mechanical and Permeation Characteristics of High strength Concrete

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Journal of Wuhan University of Technology(materials science) 2022年第3期37卷 416-422页

作者： K V s Gopala Krishna sastry m srinivasula reddy A Ravitheja Civil Engineering G Pulla Reddy Engineering CollegeKurnoolAPIndia sVR Engineering College NandyalAndhra PradeshIndia

Efforts have been made to evaluate the influences of the addition of nanoparticles on the strength,durability and mineralogical changes of high strength concrete(HsC).Therefore,mixes were prepared for conventional concrete mix(CCm)of m80 ***,various mixes were prepared by replacing cementitious materials initially with 1%Nano-CaCO_(3)(NC),2%NC,3%NC in the CCm,and then 1%NC and Nano-siO_(2)(Ns)Ns,2%NC and Ns,3%NC and Ns(NC and Ns were in equal proportion)in the *** developed concretes were then evaluated for mechanical properties,permeation characteristics,and mineralogical *** the studies,it is found that the concrete at 2%NCs possesses superior mechanical and superior permeation characteristics of all the mixes.A clear variation in the mineralogical structure with the addition of nanoparticles has been observed.

关键词： high strength concrete nano silicon dioxide nano calcium carbonate mechanical properties permeation properties

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microstructure and mechanical properties of similar and dissimilar metal gas tungsten constricted arc welds:maraging steel to 13-8 mo stainless steel

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Defence Technology（防务技术） 2019年第1期15卷 111-121页

作者： C.V.s.murthy A.Gopala Krishna G.m.reddy Defence Research and Development Laboratory Jawaharlal Nehru Technological University Defence metallurgical Research Laboratory

maraging steel (250) and 13-8 mo stainless steel plates were joined by gas tungsten constricted arc welding(GTCAW) process in similar and dissimilar metal combinations using 13-8 mo stainless steel filler wire. The similar and dissimilar metal welds made in solutionized condition were subjected to standard post weld hardening treatments direct ageing at 485 ℃, soaking for 31/2 hours followed by air cooling(ageing treatment of maraging steel) and direct ageing at 510 ℃, soaking for 4 h followed by air cooling(ageing treatment of 13-8 mo stainless steel). The joint characterization studies include microstructure examination, microhardness survey across the weldments and transverse weld tensile *** and dissimilar metal weldments responded to both the post weld ageing treatment. After post weld aging, increase in yield strength, UTs and slight reduction in % elongation of similar and dissimilar metal were observed. The observed tensile properties were correlated with microstructure and hardness distribution across the welds.

关键词： maraging steel(250) 13-8 mo stainless steel mechanical properties microstructure

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The myth of “minima” and “maxima”,the species of Physalis in the Indian subcontinent

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植物分类学报 2007年第2期45卷 239-245页

作者： Vatsavaya s RAJU C s reddy K G RAJARAO Department of Botany Kakatiya UniversityWarangal 506009 India Forestry & Ecology Division National Remote Sensing AgencyHyderabad 500008 India Department of Botany Andhra UniversityWaltair 530003 India

The status of the names, Physalis minima L. and P. maxima mill. (solanaceae), and their alleged presence on the Indian subcontinent are discussed. The issues of nativity and identity of Linnaean Physalis minima are long-debated while the use of the name P. maxima mill. and its report from India are recent. The available evidence indicates that the name "P. minima L." is misapplied to two different elements, viz., P. angulata L. and P. lagascae Roem. & schult. The name Physalis minima L. may be rejected as nomen confusum, for which the paper provides the primary information. As on today, it is submerged under the synonymy of P. angulata L. The correct name for the widely known P. minima is P. lagascae. The name "P. maxima mill." applied to the escape and naturalized weed in the Indian subcontinent and elsewhere is to be substituted by P. pruinosa L., a name misapplied to P. grisea (Waterf.) m. martínez.

关键词：酸浆属植物酸浆值植物分类植物命名

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Experimental investigation on strip inserts in a circular tube heat transfer effect of conical under laminar flow

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Frontiers in Energy 2016年第2期10卷 136-142页

作者： m. ARULPRAKAsAJOTHI K. ELANGOVAN K. HEmA CHANDRA reddy s. sUREsH Department of mechanical Engineering Jawaharlal Nehru Technologi-cal University Anantapur Anantapur 515002 India Department of mechanical Engineering Cambridge Institute ofTechnology Bangalore 560036 India Department of mechanical Engineering National Institute of Technology Trichy 620015 India

The aim of this paper is to observe the Nusselt number and friction factor behavior of the circular tube with conical strip inserts as turbulators in a laminar flow condition, using staggered and non-staggered conical strips with three different twist ratios （Y = 2, 3 and 5）. The conical strip is inserted in the forward and backward direction individually compared to the flow of water which is the working fluid. The results indicate that the conical strip inserts increases the Nusselt number when compared to the plain surface tube. It is observed that the strip geometry has a major effect on the thermal performance of the circular tube. On examination of different strips for determining the enhancement of Nusselt number, the staggered conical strip with the twist ratio of Y = 3 has given a better result compared to the other two strips. Finally, correlations have been derived using regression analysis for predicting the Nusselt number and friction factor.

关键词： Nusselt number friction factor conical strip

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stability of stratified shear flows in channels with variable cross sections

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Applied mathematics and mechanics(English Edition) 2015年第11期36卷 1459-1480页

作者： V.R.reddy m.sUBBIAH Department of mathematics Pondicherry University

For the instability problem of density stratified shear flows in sea straits with variable cross sections, a new semielliptical instability region is found. Rurthermore, the instability of the bounded shear layer is studied in two cases：（i） the density which takes two different constant values in two layers and （ii） the density which takes three different constant values in three layers. In both cases, the dispersion relation is found to be a quartic equation in the complex phase velocity. It is found that there are two unstable modes in a range of the wave numbers in the first case, whereas there is only one unstable mode in the second case.

关键词： hydrodynamic stability shear flow variable density sea strait variablecross section

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mechanical properties of Ni_(0.83)Co_(0.15)Cu_(0.02)Fe_(1.9)O_(4-δ)+PbZr_(0.52)Ti_(0.48)O_(3)particulate composites by composite oscillator technique and the correlation with the results of magnetoelectric properties

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Journal of Advanced Ceramics 2012年第4期1卷 317-326页

作者： m.Venkata RAmANA m.Penchal reddy N.Ramamanohar reddy B.s.mURTY K.V.sIVA KUmAR shenhua sONG shenzhen Key Laboratory of Advanced materials Department of Materials Science and EngineeringShenzhen Graduate SchoolHarbin Institute of TechnologyShenzhen 518055China Department of Physics Changwon National UniversityChangwonRepublic of Korea Ceramic Composite materials Laboratory Department of PhysicsSri Krishnadevaraya UniversityAnantapur 515003India Nanotechnology Laboratory Department of Metallurgical and Materials EngineeringIndian Institute of TechnologyChennai 600036India

The xNi_(0.83)Co_(0.15)Cu_(0.02)Fe_(1.9)O_(4-δ)+PbZr_(0.52)Ti_(0.48)O_(3)(PZT)particulate magneto ferroelectric composites with x=0,0.1,0.2,0.3,0.4,0.5 and 0.6 mole fraction were prepared by conventional ceramic double sintering *** presence of two phases(perovskite structure of ferroelectric phase and spinal structure of ferromagnetic phase)was confirmed by X-ray *** magnetoelectric(mE)property of the particulate composites was determined at room temperature as a function of intensity of magnetic *** temperature variation of the longitudinal modulus(L)and the internal friction(Q−1)of these particulate composites at 104.3 kHz was studied in the wide temperature range 30-420℃.The temperature variation of the longitudinal modulus in each composition of these particulate composites showed two abrupt *** minimum coincided with the ferroelectric-paraelectric Curie transition temperature(θE)and the other with the ferromagnetic-paramagnetic Curie transition temperature(θm).The internal friction measurement also showed two sharp peaks in each composition corresponding to those temperatures where the minima were noticed in the temperature variation of the longitudinal modulus behaviour.

关键词： X-ray diffraction magnetoelectric effect piezoelectric coefficient internal friction Curie transition temperature

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