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Rare earth metal doped CeO_2-based catalytic materials for diesel soot oxidation at lower temperatures

Journal of Rare Earths 2015年第11期33卷 1162-1169页

作者： A.Rangaswamy Putla Sudarsanam benjaram m.reddy Inorganic and Physical Chemistry Division CSIR-Indian Institute of Chemical Technology Centre for Advanced materials and Industrial Chemistry (CAmIC) School of Applied Sciences RMIT University

In this work, the influence of trivalent rare-earth dopants（Sm and La） on the structure-activity properties of CeO2 was thoroughly studied for diesel soot oxidation. For this, an optimized 40% of Sm and La was incorporated into the CeO2 using a facile coprecipitation method from ultra-high dilute aqueous solutions. A systematic physicochemical characterization was carried out using X-ray diffraction（XRD）, transmission electron microscopy（TEm）, Brumauer-Emmett-teller method（BET） surface area, X-ray photoelectron spectroscopy（XPS）, Raman, and H2-temperature programmed reduction（TPR） techniques. The soot oxidation efficiency of the catalysts was investigated using a thermogravimetric method. The XRD results suggested the formation of nanocrystalline single phase CeO2-Sm2O3 and CeO2-La2O3 solid solutions. The Sm- and La-doped CeO2 materials exhibited smaller crystallite size and higher BET surface area compared with the pure CeO2. Owing to the difference in the oxidation states of the dopants（Sm3＋ and La3＋） and the Ce4＋, a number of oxygen vacancies were generated in CeO2-Sm2O3 and CeO2-La2O3 samples. The H2-TPR studies evidenced the improved reducible nature of the CeO2-Sm2O3 and CeO2-La2O3 samples compared with the CeO2. It was found that the addition of Sm and La to the CeO2 outstandingly enhanced its catalytic efficiency for the oxidation of diesel soot. The observed 50% soot conversion temperatures for the CeO2-Sm2O3, CeO2-La2O3 and CeO2 were ~790, 843 and 864 K（loose contact）, respectively, and similar activity order was also found under the tight contact condition. The high soot oxidation efficacy of the CeO2-Sm2O3 sample was attributed to numerous catalytically favourable properties, like smaller crystallite size, larger surface area, abundant oxygen vacancies, and superior reducible nature.

关键词： rare earths cerium oxide solid solutions oxygen vacancies soot oxidation

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非负载和氧化铝负载的纳米CeO_2-ZrO_2和CeO_2-Te_2O_3固溶体催化CO氧化(英文)

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催化学报 2011年第5期32卷 800-806页

作者： m.reddy benjaram Thrimurthulu GODE Lakshmi KATTA Inorganic and Physical Chemistry Division Indian Institute of Chemical Technology

Ceria-zirconia(CZ)and ceria-terbia(CT)and alumina-supported ceria-zirconia(CZA)and ceria-terbia(CTA)solid solutions were synthesized by coprecipitation and deposition precipitation methods,*** characteristics and catalytic activity of the synthesized samples have been investigated using X-ray diffraction(XRD),high resolution transmission electron microscopy(HRTEm),X-ray photoelectron spectroscopy(XPS),Raman spectroscopy(RS),and Brunauer-Emmett-Teller(BET)surface area *** evaluate the catalytic properties,total oxygen storage capacity and CO oxidation activity measurements were carried *** XRD analyses revealed the formation of Ce0.75Zr0.25O2 phase for CZ and Ce0.5Zr0.5O2 and Ce0.6Zr0.4O2 phases for CZA samples,*** the formation of only Ce0.8Tb0.2O2-δphase was noted for both CT and CTA *** the supported and unsupported samples adopted a fluorite-type structure and exhibited cell parameters with respect to Vegard's *** HRTEm results indicated well-dispersed particles of the size around 5 *** RS measurements suggested the presence of oxygen vacancies due to defective structure *** XPS studies revealed the presence of cerium in both Ce 4+ and Ce 3+ oxidation states in different *** was found that CO oxidation for CTA occurs at very much lower temperature than CT,CZ,and CZA *** of these findings by correlating with the structural characterization studies are consolidated.

关键词： ceria zirconia terbia alumina-support deposition coprecipitation CO oxidation

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Time-resolved, defect-hosted, trace element mobility in deformedWitwatersrand pyrite

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Geoscience Frontiers 2019年第1期10卷 55-63页

作者： Denis Fougerouse Steven m.reddy Christopher L.Kirkland David W.Saxey William D.Rickard Robert m.Hough School of Earth and Planetary Sciences The Institute for Geoscience Research (TIGeR) Curtin University Geoscience Atom Probe Advanced Resource Characterisation Facility John de Laeter Centre Curtin University CSIRO minerals Resources

The Pb isotopic composition of rocks is widely used to constrain the sources and mobility of melts and hydrothermal fluids in the Earth's crust. In many cases, the Pb isotopic composition appears to represent mixing of multiple Pb reservoirs. However, the nature, scale and mechanisms responsible for isotopic mixing are not well known. Additionally, the trace element composition of sulphide minerals are routinely used in ore deposit research, mineral exploration and environmental studies, though little is known about element mobility in sulphides during metamorphism and deformation. To investigate the mechanisms of trace element mobility in a deformed Witwatersrand pyrite(FeS_2), we have combined electron backscatter diffraction(EBSD) and atom probe microscopy(APm). The results indicate that the pyrite microstructural features record widely different Pb isotopic compositions, covering the entire range of previously published sulphide Pb compositions from the Witwatersrand basin. We show that entangled dislocations record enhanced Pb, Sb, Ni, Tl and Cu composition likely due to entrapment and short-circuit diffusion in dislocation cores. These dislocations preserve the Pb isotopic composition of the pyrite at the time of growth(~3 Ga) and show that dislocation intersections, likely to be common in deforming minerals, limit trace element mobility. In contrast, Pb, As, Ni, Co, Sb and Bi decorate a highangle grain boundary which formed soon after crystallisation by sub-grain rotation *** isotopic composition within this boundary indicates the addition of externally-derived Pb and trace elements during greenschist metamorphism at ~2 Ga. Our results show that discrete Pb reservoirs are nanometric in scale, and illustrate that grain boundaries may remain open systems for trace element mobility over 1 billion years after their formation.

关键词： Atom probe microscopy Nanoscale Nanogeochronology microstructure Isotope geochemistry Common Pb

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Bayesian geological and geophysical data fusion for the construction and uncertainty quantification of 3D geological models

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Geoscience Frontiers 2021年第1期12卷 479-493页

作者： Hugo K.H.Olierook Richard Scalzo David Kohn Rohitash Chandra Ehsan Farahbakhsh Chris Clark Steven m.reddy R.Dietmar müller School of Earth and Planetary Sciences Curtin UniversityGPO Box U1987PerthWA6845Australia Centre for Translational Data Science University of SydneyNSW2006SydneyAustralia Sydney Informatics Hub University of SydneyNSW2006SydneyAustralia EarthByte Group School of GeosciencesUniversity of SydneyNSW2006SydneyAustralia Timescales of mineral Systems and John de Laeter Centre Curtin UniversityGPO Box U1987PerthWA6845Australia School of mathematics and Statistics University of New South WalesSydneyNSW2052Australia Department of mining Engineering Amirkabir University of Technology(Tehran Polytechnic)TehranIran

Traditional approaches to develop 3D geological models employ a mix of quantitative and qualitative scientific techniques,which do not fully provide quantification of uncertainty in the constructed models and fail to optimally weight geological field observations against constraints from geophysical ***,using the Bayesian Obsidian software package,we develop a methodology to fuse lithostratigraphic field observations with aeromagnetic and gravity data to build a 3D model in a small(13.5 km×13.5 km)region of the Gascoyne Province,Western *** approach is validated by comparing 3D model results to independently-constrained geological maps and cross-sections produced by the Geological Survey of Western *** fusing geological field data with aeromagnetic and gravity surveys,we show that 89%of the modelled region has>95%certainty for a particular geological unit for the given model and *** boundaries between geological units are characterized by narrow regions withm wide at the Earth's surface and 500-2000 m wide at ***~4 km depth,the model requires geophysical survey data with longer wavelengths(e.g.,active seismic)to constrain the deeper *** Obsidian was originally built for sedimentary basin problems,there is reasonable applicability to deformed terranes such as the Gascoyne ***,modification of the Bayesian engine to incorporate structural data will aid in developing more robust 3D ***,our results show that surface geological observations fused with geophysical survey data can yield reasonable 3D geological models with narrow uncertainty regions at the surface and shallow subsurface,which will be especially valuable for mineral exploration and the development of 3D geological models under cover.

关键词： Capricorn orogen machine learning Bayesian inference markov chain monte Carlo Solid earth mineral exploration

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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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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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Effect of Hardfaced Interlayer Thickness and Low Hydrogen Ferritic Capping on Ballistic Performance of Shielded metal Arc Welded Armour Steel Joints

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Journal of Iron and Steel Research International 2013年第12期20卷 82-91页

作者： m Balakrishnan V Balasubramanian G madhusudhan reddy Center for materials Joining and Research(CEmAJOR) Department of Manufacturing EngineeringAnnamalai University Solidification Technology Division Metal Joining GroupDefense Metallurgical Research Laboratory(DMRL)

Armour grade quenched and tempered steel closely confirming to AISI 4340 is well known for its superior ballistic performance and hence used in the fabrication of combat vehicles. The traditional fillers like austenitic stain- less steel showed poor ballistic performance of these welded joints as compared to the base metal. Attempts have been made to deposit hardfaced interlayer between austenitic stainless steel weld metals. Though this method, mar-- ginal improvements in ballistic performance can be yielded, and cracks were observed in between base metal and hardfaced layer. Thickness of the hardfaced interlayer plays a vital role for the effective ballistic performance. Thus, an attempt has been made to investigate the effect of hardfaced interlayer thickness on ballistic performance of ar- mour steel welds. The results of effect of buttering, low hydrogen ferritic （LHF） filler and three different hardfaced layer thicknesses （4, 5.5 and 7 ram） on ballistid performance of shielded metal arc welded armour steel joints were given.

关键词： armour steel low hydrogen ferritic electrode sandwich structure ballistic performance hardfacing metallography

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Environment friendly protocol for the synthesis of nitriles from aldehydes

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Chinese Chemical Letters 2010年第9期21卷 1025-1028页

作者： m.B.madhusudana reddy m.A.Pasha Department of Studies in Chemistry Central College CampusBangalore University

A rapid and eco-friendly one-pot protocol for the synthesis of nitriles has been developed by treating various araldehydes bearing electron withdrawing as well as electron donating groups with hydroxylamine hydrochloride in the presence of non-toxic,non-corrosive and reusable zinc oxide（ZnO） as the catalyst under solvent-free microwave *** present approach offers the advantages of a clean reaction,simple methodology,employing readily available catalyst,short reaction duration（〈1 min）,high selectivity;and high yield（90-98%）.

关键词： Aldehydes Nitriles Solvent-free microwave irradiation Benign procedure

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Ear Field Adaptive Noise Control for Snoring:An Real-time Experimental Approach

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IEEE/CAA Journal of Automatica Sinica 2019年第1期6卷 158-166页

作者： Lichuan Liu Karunakar reddy Pottim Sen m.Kuo IEEE the Electrical Engineering Department Northern Illinois University the Department of Electrical Engineering Chung Yuan Christian University

In this paper, an active noise control(ANC) system is developed to provide an effective and non-intrusive solution for reducing loud snoring to provide a quiet environment for a snorer's bed partner. An adaptive least mean square(LmS)algorithm optimized for different kinds of snore signals is introduced and theoretically analyzed. Also, a residual noise masking approach is proposed to further reduce the effect of the snore noise without interfering with the LmS algorithm. Computer simulations followed by real-time experiments are conducted to demonstrate the feasibility of the snore ANC systems based on a pillow setup. For the optimum effect based on the characteristics of human hearing, the performance of the proposed approach is evaluated by using the multi-channel feedforward ANC systems based on the filtered-X least mean square(FXLmS) *** with a traditional headboard setup for snoring noise control, the proposed snore ANC systems optimized for ear field operation yield much higher noise reduction around the ears of the snorer's bed partner.

关键词： Active noise control (ANC) audio integrated ANC ear field filtered-X least mean square (FXLmS) snore multi-channel

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Electro-magneto-hydrodynamic flow of couple stress nanofluids in micro-peristaltic channel with slip and convective conditions

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Applied mathematics and mechanics(English Edition) 2021年第4期42卷 593-606页

作者： K.RAmESH m.G.reddy B.SOUAYEH Department of mathematics Symbiosis Institute of TechnologySymbiosis International(Deemed University)Pune 412115India Department of mathematics Acharya Nagarjuna UniversityOngole CampusOngole 523001India Department of Physics College of ScienceKing Faisal UniversityAl-Ahsa 31982Saudi Arabia Laboratory of Fluid mechanics Physics DepartmentFaculty of Sciences of TunisUniversity of Tunis El ManarTunis 2092Tunisia

This study explores the effects of electro-magneto-hydrodynamics,Hall currents,and convective and slip boundary conditions on the peristaltic propulsion of nanofluids(considered as couple stress nanofluids)through porous symmetric *** phenomena of energy and mass transfer are considered under thermal radiation and heat source/*** governing equations are modeled and non-dimensionalized under appropriate dimensionless *** resulting system is solved numerically with mATHEmATICA(with an in-built function,namely the Runge-Kutta scheme).Graphical results are presented for various fluid flow quantities,such as the velocity,the nanoparticle temperature,the nanoparticle concentration,the skin friction,the nanoparticle heat transfer coefficient,the nanoparticle concentration coefficient,and the trapping *** results indicate that the nanoparticle heat transfer coefficient is enhanced for the larger values of thermophoresis ***,an intriguing phenomenon is observed in trapping:the trapped bolus is expanded with an increase in the Hartmann ***,the bolus size decreases with the increasing values of both the Darcy number and the electroosmotic parameter.

关键词： peristalsis magnetohydrodynamics(mHD) nanofluid Hall current porous medium thermal radiation

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