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Determination of genotoxic alkyl methane sulfonates and alkyl paratoluene sulfonates in lamivudine using hyphenated techniques

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Journal of Pharmaceutical Analysis 2012年第4期2卷 314-318页

作者： N.v.v.s.s.raman A.v.s.s.Prasad K.Ratnakar reddy K.Ramakrishna Hetero Drugs Ltd.(R&D) GITAM Institute of science GITAM University

Two highly sensitive methods for the determination of genotoxic alkyl methane sulfonates (AMss) and alkyl paratoluene sulfonates (APTss) in lamivudine using hyphenated techniques have been presented. AMss were determined by GC-Ms method using GsBPINOWAX (30 m 0.25 mm 0.25 mm) column. Temperature program was set by maintaining at 100 1C initially for 3 min, then rised to 220 1C at the rate of 15 1C/min and maintained at 220 1C for 16 min. N,N-dimethyl formamide was used as diluent. APTss were determined by LC-Ms using Zorbax, Rx C8, 250 mm 4.6 mm, 5 mm column as stationary phase. 0.01 M ammonium acetate is used as buffer. The mixture of buffer and methanol in 75:25 (v/v) ratio was used as mobile phase A and mixture of buffer and methanol in 5:95 (v/v) ratio was used as mobile phase B. The gradient program (T/%B) was set as 0/28, 16/50, 17/100, 23/100, 27/28 and 40/28. Both the methods were validated as per International Conference on Harmonization guidelines. Limit of quantitation was found 1.5 mg/mL for AMss and was in the range of 1.0-1.5 mg/mL for APTss.

关键词： Genotoxins Alkyl methane sulfonates Alkyl paratoluene sulfonates Lamivudine Hyphenated techniques

Experimental Evaluation of a Multistage Reciprocating Evaporative Cooler Performance for varied Climatic Conditions

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Journal of Thermal science 2023年第4期32卷 1523-1535页

作者： sampath sURANJAN sALINs s.v.KOTA reddy shiva KUMAR school of Engineering and IT Manipal Academy of Higher EducationDubai CampusDubaiPO 345050UAE Mechanical Engineering Department VIT-AP UniversityAmaravatiAndra Pradesh52223India Department of Mechanical and Manufacturing Engineering Manipal Institute of TechnologyManipal Academy of Higher EducationManipal576104India

Current system focuses on design&construction of a multistage reciprocating evaporative cooling test *** packings that are used will undergo the reciprocating action,powered by the cam follower mechanism maintained at an actual rotation *** dry bulb temperature&humidity values are varied to replicate the varying climatic conditions,and the output parameters such as cooling load,evaporation rate(ER),humidification efficiency(HE),coefficient of performance(COP)are *** results showed that as inlet humidity raises,the performance of system *** the rise in the camshaft speed or packing velocity,there is an upsurge in the performance until a cam speed of 10 r/min or packing velocity of 0.083 m/s and with further increases in the value,overall performance *** system gave a maximum COP,ER,and HE equal to 3.80,73.87%,and 0.53 g/kg respectively.A rise in the inlet air temperature yielded a maximum change in dry bulb temperature of 8.2℃.Overall,results indicated that evaporative cooling is more effective in arid climates than the cold and humid *** quality test is performed to measure CO_(2),Total volatile Organic Compound(TvOC),and Formaldehyde(HCHO),and it is found that humidified air entering the defined space is of excellent quality.

关键词： multistage humidifier evaporative cooling reciprocating packing humidification efficiency

Recent trends on energy-efficient solar dryers for food and agricultural products drying: a review

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WAsTE DIsPOsAL & sUsTAINABLE ENERGY 2024年第3期6卷 335-353页

作者： venkateswarlu, Kavati reddy, s. v. Kota Univ Namibia Sch Engn & Built Environm Mech Engn JEDS CampusPrivate Bag 3624 Ongwediva Oshakati Namibia vIT AP Univ Sch Mech Engn SMEC Amaravati 522237 Andhra Pradesh India

The energy efficiency enhancement of solar dryers has attracted the attention of researchers worldwide because of the need for energy storage in solar drying applications, which arises primarily from the irregular nature of solar energy that leads to improper drying which will reduce the quality of the products being dried. This work comprehensively reviews the state-of-the-art research carried out on solar dryers for energy efficiency enhancement using various alternative strategies, including hybrid solar dryers that use auxiliary heating sources, such as electric heaters or biomass heaters, solar-assisted heat pump dryer, use of desiccant materials, and heat storage systems that use both sensible and latent heat storage. The advent of phase change materials (PCM), such as thermally and chemically stable PCMs, for long-term storage, bio-degradable and bio-compatible PCM materials to alleviate the negative environmental impact of conventional PCMs is also presented. The performance parameters considered for evaluating dryers include the maximum temperature attained inside the drying chamber, drying time and efficiency, specific moisture extraction rate (sMER), energy and exergy efficiency and CO2 mitigation effect. The factors considered to analyze the PCMs application in solar dryers include cost and sustainability of PCMs, and both energy and exergy analyses of dryers using PCMs. The gaps in current knowledge and future scope for further improvement of solar dryers are also elucidated.

关键词： Agricultural and food products Desiccant materials Hybrid dryers Phase change material solar-assisted heat pump dryers Thermal energy storage

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

Effect of Welding Processes and Consumables on Tensile and Impact Properties of High strength Quenched and Tempered steel Joints

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Journal of Iron and steel Research International 2008年第6期15卷 87-94页

作者： G Magudeeswaran v Balasubramanian G Madhusudhan reddy T s Balasubramanian Center for Advanced Materials Joining and Research(CEMAJOR) Department of Manufacturing EngineeringAnnamalai University Metal Joining section Defence MetallurgicalResearch Laboratory special vehicles Division Combat Vehicles Research and Development Establishment

Quenched and tempered steels are prone to hydrogen induced cracking in the heat affected zone after welding. The use of austenitic stainless steel consumables to weld the above steel was the only available remedy because of higher solubility for hydrogen in austenitic phase. In this investigation, an attempt was made to determine a suitable consumable to replace expensive austenitic consumables. Two different consumables, namely, austenitie stain less steel and low hydrogen ferritic steel, were used to fabricate the joints by shielded metal are welding （sMAW） and flux cored arc welding （FCAW） processes. The joints fabricated by using low hydrogen ferritic steel consumables showed superior transverse tensile properties, whereas joints fabricated by using austenitic stainless steel consumables exhibited better impact toughness, irrespective of the welding process used. The sMAW joints exhibited superior mechanical and impact properties, irrespective of the consumables used, than their FCAW counterparts.

关键词： shielded metal arc welding process flux cored arc welding process austenitie stainless steel low hydro gen ferritic steel transverse tensile property impact toughness

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

Experimental and numerical investigation on under-water friction stir welding of armour grade AA2519-T87 aluminium alloy

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Defence Technology（防务技术） 2016年第4期12卷 324-333页

作者： s.sREE sABARI s.MALARvIZHI v.BALAsUBramanIAN G.MADUsUDHAN reddy Centre for Materials Joining and Research (CEMAJOR) Department of Manufacturing Engineering Annamalai University Metal Joining section Defense Metallurgical Research Laboratory (DMRL)

Friction stir welding(FsW) is a promising welding process that can join age hardenable aluminium alloys with high joint efficiency. However,the thermal cycles experienced by the material to be joined during FsW resulted in the deterioration of mechanical properties due to the coarsening and dissolution of strengthening precipitates in the thermo-mechanical affected zone(TMAZ) and heat affected zone(HAZ). Under water friction stir welding(UWFsW) is a variant of FsW process which can maintain low heat input as well as constant heat input along the weld line. The heat conduction and dissipation during UWFsW controls the width of TMAZ and HAZ and also improves the joint properties. In this investigation, an attempt has been made to evaluate the mechanical properties and microstructural characteristics of AA2519-T87 aluminium alloy joints made by FsW and UWFsW processes. Finite element analysis has been used to estimate the temperature distribution and width of TMAZ region in both the joints and the results have been compared with experimental results and subsequently correlated with mechanical properties.? 2016 China Ordnance society. Production and hosting by Elsevier B.v. All rights reserved.

关键词： Aluminium alloy Friction stir welding Underwater friction stir welding Mechanical properties Microstructural characteristics Finite element analysis

MHD and viscous Dissipation Effects in Marangoni Mixed Flow of a Nanofluid over an Inclined Plate in the Presence of Ohmic Heating

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Fluid Dynamics & Materials Processing 2021年第2期17卷 285-300页

作者： D.R.v.s.R.K.sastry peri K.Kameswaran Mohammad Hatami Department of Mathematics SASTRA UniversityTamilnaduIndia Department of Mathematics School of Advanced SciencesVIT UniversityTamilnaduIndia Mechanical Engineering Department Esfarayen University of TechnologyEsfarayenIran

The problem of Marangoni mixed convection in the presence of an inclined magnetic field with uniform strength in a nanofluid(formed by the dispersion of two metallic nanoparticles,i.e.,Copper(Cu),and alumina(Al_(2)O_(3))in water)is addressed *** effects of viscous dissipation and Ohmic heating are also *** original set of governing partial differential equations is reduced to a set of non-linear coupled ordinary differential equations employing the similarity transformation *** simplified equations are numerically solved through MATLAB‘bvp4c’*** results are presented in terms of graphs for several *** is found that enhancing the stratification parameter leads to a decrease in the fluid temperature,and an increase in the aligned magnetic field angle reduces the flow ***,mixed convection tends to enhance both the Nusselt and sherwood *** the angle of inclination is made higher,the fluid velocity is reduced and the thickness of the thermal and concentration boundary layer grows.

关键词： viscous dissipation inclined magnetic field marangoni mixed convection nanofluid

Optical and Microstructural Characterisations of Pulsed rf Magnetron sputtered Alumina Thin Film

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Journal of Materials science & Technology 2013年第10期29卷 929-936页

作者： I.Neelakanta reddy v.Rajagopal reddy N.sridhara s.Basavaraja A.K.sharma Arjun Dey Thermal systems Group ISRO Satellite CentreVimanapura Post Department of Physics Sri Venkateswara University Bruker India Nanotechnology Laboratory Jawaharlal Nehru Centre for Advanced Scientifc Research (JNCASR)

Alumina thin films were deposited on fused quartz and ss304 substrate by pulsed rf magnetron sputtering with both direct and reactive methods. The films were characterised by energy dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, field emission scanning electron microscopy and atomic force microscopy to reveal the microstructure, surface morphology and topography of thin films. Transmittance and reflectance of alumina thin film were evaluated after deposition on the quartz substrate. Transmittance of the quartz remains almost un-altered when alumina was deposited by the reactive sputtering. A marginal decrease of ~4% in the transmittance of quartz was, however, observed after deposition of alumina by direct sputtering. Infrared emittance of the substrate also remains almost constant after deposition of thin alumina film. Further, as-deposited alumina on ss304 obtained by both direct and reactive sputtering process was amorphous in nature. However, after annealing crystalline peaks were observed.

关键词： Alumina Thin film rf magnetron sputtering Microstructure Transmittance Reflectance Infrared emissivity