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Journal of Pharmaceutical Analysis 2012年第3期2卷 167-173页

作者： vijaya Kumari Karra Nageswara rao Pilli Jaswanth Kumar Inamadugu J.v.L.N.Seshagiri rao University College of Pharmaceutical Sciences Jawaharlal Nehru Technological UniversityKukatpallyHyderabad-500085India Analytical and Environmental Chemistry Division Department of ChemistrySri Venkateswara UniversityTirupati-517502India College of Pharmaceutical Sciences Andhra UniversityVisakhapatnam-530003India

A simple and rapid liquid chromatography-tandem mass spectrometric(LC-MS/MS) assay method has been developed and fully validated for simultaneous quantification of pioglitazone and candesartan in human *** was used as an internal *** analytes were extracted from human plasma samples by solid-phase extraction technique using a Strata-X 33 mm polymeric *** reconstituted samples were chromatographed on a C18 column by using a 80:20(v/v) mixture of acetonitrile and 0.1% formic acid as the mobile phase at a flow rate of 0.8 mL/*** calibration curves obtained were linear(rZ0.99) over the concentration range of 15-3000 ng/mL for pioglitazone and 5-608 ng/mL for *** results of the intra-and inter-day precision and accuracy studies were well within the acceptable limits.A run time of 2.7 min for each sample made it possible to analyze more than 300 plasma samples per *** proposed method was found to be applicable to clinical studies.

关键词： Pioglitazone Candesartan Human plasma Solid-phase extraction LC-MS/MS Pharmacokinetics

e-FILTERS OF MS-ALGEBRAS

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Acta Mathematica Scientia 2013年第3期33卷 738-746页

作者： M. Sambasiva rao Department of Mathematics M.V.G.R. College of EngineeringChintalavalasa Vizianagaram Andhra Pradesh India-535005

The notion of e-filters is introduced in an MS-algebra and characterized. The concept of D-filters is introduced and a set of equivalent conditions under which every D-filter is an e-filter are given. The properties of the space of all prime e-filters of an MS-algebra are observed. The concept of D-prime filters is introduced and then a set of equivalent conditions axe derived for a prime e-filter to become a D-prime filter in topological terms.

关键词： MS-algebra e-filter dense element D-filter D-prime filter minimal prime filter Hausdorff space

Numerical modeling of friction stir welding using the tools with polygonal pins

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Defence Technology（防务技术） 2015年第3期11卷 229-236页

作者： M. MEHTA G.M. REDDY A.v. rao A. DE Production Engineering Department BVM Engineering College Defense Metallurgical Research Laboratory Mechanical Engineering Department

Friction stir welding using the tools with polygonal pins is often found to improve the mechanical strength of weld joint in comparison to the tools with circular pins. However, the impacts of pin profile on the peak temperature, tool torque and traverse force, and the resultant mechanical stresses experienced by the tool have been rarely reported in a systematic manner. An estimation of the rate of heat generation for the tools with polygonal pins is challenging due to their non-axisymmetric cross-section about the tool axis. A novel methodology is presented to analytically estimate the rate of heat generation for the tools with polygonal pins. A three-dimensional heat transfer analysis of friction stir welding is carried out using finite element method. The computed temperature field from the heat transfer model is used to estimate the torque, traverse force and the mechanical stresses experienced by regular triangular, square, pentagon and hexagon pins following the principles of solid mechanics. The computed results show that the peak temperature experienced by the tool pin increases with the number of pin sides. However, the resultant maximum shear stress experienced by the pin reduces from the triangular to hexagonal pins.

关键词：搅拌摩擦焊接多边形管脚数值模拟摩擦搅拌焊接机械强度峰值温度机械应力

Evaluation of physical and mechanical properties of AZ91D/SiC composites by two step stir casting process

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Journal of Magnesium and Alloys 2015年第1期3卷 52-62页

作者： S.Aravindan P.v.rao K.Ponappa Department of Mechanical Engineering Indian Institute of Technology-DelhiDelhi 110016India Department of Mechanical Engineering Kongu Engineering CollegePerundurai 638052India

Magnesium alloy(AZ91D)composites reinforced with silicon carbide particle with different volume percentage were fabricated by two step stir casting *** effect of changes in particle size and volume fraction of SiC particles on physical and mechanical properties of composites were evaluated under as cast and heat treated(T6)*** experimental results were compared with the standard theoretical *** results reveal that the mechanical properties of composites increased with increasing SiC particles and decrease with increasing particle *** of particles and fractured surface were studied through SEM and the presence of elements is revealed by EDS study.

关键词： Magnesium alloy Metal-matrix composites(MMCs) Mechanical properties Casting Fractography

An ecofriendly approach for corrosion control of 6061 Al-15%(v)SiC(P)composite and its base alloy

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Chinese Journal of Chemical Engineering 2017年第3期25卷 363-372页

作者： Charitha B.P. Padmalatha rao Department of chemistry Manipal Institute of TechnologyManipalUdupiKamatakaIndia

Corrosion inhibition characteristics of bio polymer dextran was studied for the corrosion control of 6061 Al-15%_((v)) SiC_((P)) composite and its base alloy in 1 mol·L^(-1) HCl. Standard electrochemical techniques such as potentiodynamic polarization(PDP) measurements and electrochemical impedance spectroscopy(EIS) method were adopted for corrosion rate measurement. Surface morphology was studied by scanning electron microscopy(SEM) and elemental mapping was done by energy dispersive X-ray(EDX) analysis. Suitable mechanism was proposed for corrosion and inhibition process. Results indicated that dextran acts as an excellent anticorrosive agent for the corrosion control of 6061 Al-15%_((v)) SiC_((P)) composite, with maximum inhibition efficiency of 91% for the concentration of 0.4 g·L^(-1) at 303 K. Dextran acted as a mixed type of inhibitor, and got physically adsorbed both on composite and base alloy by obeying Langmuir adsorption isotherm. Dextran is proved to be a green inhibitor with environmental and economic benefits.

关键词： 6061 Al-15%(v) SiC(p) composite Green inhibitor Biopolymer Electrochemical studies SEM–EDX

Petrogenesis of the crater-facies Tokapal kimberlite pipe,Indrvati Basin,Central India

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Geoscience Frontiers 2014年第6期5卷 781-790页

作者： N.v.Chalapathi rao B.Lehmann B.K.Panwar Alok Kumar D.Mainkar Department of Geology Centre of Advanced StudyBanaras Hindu UniversityVaranasi 221005India Mineral Resources Technical University of Clausthal38678 Clausthal-ZellerfeldGermany Directorate of Geology and Mining RaipurChhattisgarh 492007India

New geochemical data of the crater-facies Tokapal kimberlite system sandwiched between the lower and upper stratigraphic horizons of the Mesoproterozoic lndravati Basin a：：e presented. The kimberlite has been subjected to extensive and pervasive low-temperature alteration. Spinel is the only primary phase identifiable, while olivine macrocrysts and juvenile lapilli are largely pseudomorphed （talc-serpentine- carbonate alteration）. However, with the exception of the alkalies, major element oxides display systematic fractionation trends; likewise, HFSE patterns are well correlated and allow petrogenetic interpretation. various crustal contamination indices such as （SiO2 ＋ AI：：O3 ~ Na20）]（MgO ~ K20） and Si] Mg are close to those of uncontaminated kimberlites. Similar La]Yb （＇79-109） of the Tokapal samples with those from the kimberlites of Wajrakarur （73-145） and Narayanpet （72-156）, Eastern Dharwar craton, southern India implies a similarity in their genesis. In the discriminant plots involving HFSE the Tokapal samples display strong affinities to Group 1I kimberlites from southern Africa and central India as well as to ＇transitional kimberlites＇ from the Eastern Dharwar craton, southern India, and those from the Prieska and Kuruman provinces of southern Africa. There is a striking ~;imilarity in the depleted-mantle （TOM） Nd model ages of the Tokapal kimberlite system, Bastar craton, th~ kimberlites from NKF and WKE Eastern Dharwar craton, and the Majhgawan diatreme, Bundelkhand craton, with the emplacement age of some of the lamproites from within and around the Palaeo^Mesoproterozoic Cuddapah basin, southern India. These similar ages imply a major tectonomagmatic event, possibly related to the break- up of the supercontinent of Columbia, at 1.3-1.5 Ga across the l：hree cratons. The ＇transitional＇ geochemical features displayed by many of the Mesoproterozoic po~：assic-ultrapotassic rocks, across these Indian cratons are inferred to be memories of the metasomatising f

关键词： Kimberlite Tokapal Columbia Bastar craton India

Jatropha oil methyl ester and its blends used as an alternative fuel in diesel engine

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International Journal of Agricultural and Biological Engineering 2008年第2期1卷 32-38页

作者： Y.v.Hanumantha rao Ram Sudheer voleti v.S.Hariharan A.v.Sitarama Raju Department of Mechanical Engineering Koneru Lakshmaiah College of EngineeringGreen FieldsGuntur-522502Andhra PradeshIndia Department of Mechanical Engineering Lakireddy Balireddy College of EngineeringMylavaramKrishna DtAndhra PradeshIndia Department of Mechanical Engineering Jawaharalal Nehru Technological University College of EngineeringKakinadaPin:533003Andhra PradeshIndia

Biomass derived vegetable oils are quite promising alternative fuels for agricultural diesel *** of vegetable oils in diesel engines leads to slightly inferior performance and higher smoke emissions due to their high *** performance of vegetable oils can be improved by modifying them through the transesterification *** this present work,the performance of single cylinder water-cooled diesel engine using methyl-ester of Jatropha oil as the fuel was evaluated for its performance and exhaust *** fuel properties of biodiesel such as kinematic viscosity,calorific value,flash point,carbon residue and specific gravity were *** indicate that B25 has closer performance to diesel and B100 has lower brake thermal efficiency mainly due to its high viscosity compared to *** brake thermal efficiency for biodiesel and its blends was found to be slightly higher than that of diesel fuel at tested load conditions and there was no difference of efficiency between the biodiesel and its blended *** Jatropha biodiesel and its blended fuels,the exhaust gas temperature increased with the increase of power and amount of ***,its diesel blends showed reasonable efficiencies,lower smoke,CO_(2),CO and HC emissions.

关键词： Jatropha oil bio-fuels transesterification performance and emission characteristics

Geochemical assessment of a siliceous limestone sample for cement making

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Chinese Journal Of Geochemistry 2011年第1期30卷 33-39页

作者： rao D.S. vijayakumar T.v. Prabhakar S. Bhaskar Raju G. National Metallurgical Laboratory-Madras Centre CSIR Madras Complex Taramani Chennai-600 113 India

A low grade siliceous limestone sample from the Jayantipuram mine of Andhra Pradesh, India, has been investigated for its suitability for cement making. Petrological as well as X-ray diffraction pattern studies indicated that the limestone sample was crystalline and dominantly composed of calcite and quartz. They are simple in mineralogy, and yet they have variable silica and lime contents. Geochemical analysis results of twenty five hand picked samples indicated that the limestone from the Jayantipuram mine shows a wide range of variations in LOI (29.94% to 40.64%), SiO2 (6.14% to 27.18%), CaO (37.93% to 50.78%), Al2O3 (0.49% to 2.27%) and Fe2O3 (0.28% to 2.4%). MgO, K2O, Na2O, TiO2 and MnO2 are present in traces. CaO with LOI shows a strong positive correlation where as CaO with SiO2 shows a strong negative correlation because of mineralogical factors. The chemical composition of the limestone reflects its mineralogical composition. The distribution of various elements in the acid-soluble fraction has been studied by the factor analysis method in order to interpret in terms of their mineralogy, sedimentary environment and diagenesis. Mineralogy, recrystallization and other diagenetic changes are the main factors affecting the distribution of the elements and their mutual relationships in the limestone. The aim of this paper is also to analyze how significantly the two parameters, silica modulus and lime saturation factor, influence this low grade siliceous limestone sample from the Jayantipuram mine of Andhra Pradesh, India, for the cement making process from the geochemical data.

关键词：灰岩样品水泥生产地球化学硅质石灰石矿评估因子分析方法化学数据处理

Microstructure and Mechanical Properties of Friction Stir Lap Welded Aluminum Alloy AA2014

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Journal of Materials Science & Technology 2012年第5期28卷 414-426页

作者： S. Babu G.D. Janaki Ram P.v. venkitakrishnan G. Madhusudhan Reddy K. Prasad rao Dept. of Metallurgical and Materials Engineering Indian Institute of Technology Madras Chennai India Liquid Propulsion Systems Centre Indian Space Research Organisation Tiruvananthapuram India Defence Metallurgical Research Laboratory Hyderabad India

Friction stir lap welds were produced in 3 mm thick Alclad sheets of Al alloy 2014-T4 using two different tools （with triangular and threaded taper cylindrical pins）. The effects of tool geometry on weld microstructure, lap-shear performance and failure mode were investigated. The pin profile was found to significantly influence the hook geometry, which in turn strongly influenced the joint strength and the failure mode. Welds produced in alloy 2014-T4 Alclad sheets by using triangular and threaded taper cylindrical tools exhibited an average lap-shear failure load of 16.5 and 19.5 kN, respectively, while the average failure load for standard riveted joints was only 3.4 kN. Welds produced in alloy 2014-T6 Alclad sheets and in alloy 2014-T4 bare sheets （i.e., no Alclad） were comparatively evaluated with those produced in alloy 2014-T4 Alclad sheets. While the welds made （with threaded taper cylindrical tool） in T6 and T4 conditions showed very similar lap-shear failure loads, the joint efficiency of the welds made in T6 condition （43%） was considerably lower （because of the higher base material strength） than those made in T4 condition （51%）. The Alclad layers were found to present no special problems in friction stir lap welding. Welds made with triangular tool in alloy 2014-T4 Alclad and bare sheets showed very similar lap-shear failure loads. The present work provides some useful insights into the use of friction stir welding for joining Al alloys in lap configuration.

关键词： Aluminum alloys Friction stir welding Lap joints Lap-shear testing

Effect of welding processes on mechanical and microstructural characteristics of high strength low alloy naval grade steel joints

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Defence Technology（防务技术） 2015年第3期11卷 308-317页

作者： S.RAGU NATHAN v.BALASUBRAMANIAN S.MALARvIZHI A.G.rao Department of Manufacturing Engineering Annamalai University Centre for Materials Joining & Research (CEMAJOR) Department of Manufacturing EngineeringAnnamalai University Naval Materials Research Laboratory (NMRL)

Naval grade high strength low alloy(HSLA) steels can be easily welded by all types of fusion welding processes. However, fusion welding of these steels leads to the problems such as cold cracking, residual stress, distortion and fatigue damage. These problems can be eliminated by solid state welding process such as friction stir welding(FSW). In this investigation, a comparative evaluation of mechanical(tensile, impact,hardness) properties and microstructural features of shielded metal arc(SMA), gas metal arc(GMA) and friction stir welded(FSW) naval grade HSLA steel joints was carried out. It was found that the use of FSW process eliminated the problems related to fusion welding processes and also resulted in the superior mechanical properties compared to GMA and SMA welded joints.

关键词：低合金高强度钢焊接工艺钢接头组织结构力学性能搅拌摩擦焊机械特性焊接方法