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Synthesis and characterization of organomodified na-MMT using cation and anion surfactants

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中国化学前沿:英文版 2011年第2期6卷 153-158页

作者： K.R.Vishnu MAhESh h.n.narasimha murthy B.E.KUMARASWAMY n.RAGhAVEnDRA R.SRIDhAR M.KRIShnA niranjan PATTAR Ratna PAL B.S.Sherigara Department of P.G Studies and Research in Industrial Chemistry Kuvempu UniversityShankaraghattaShimoga 577451India Department of Mechanical Engineering R V College of EngineeringBangalore 560059India

The Sodium Montmorillonite(na-MMT)is not susceptible to polymer due to its organophilic character and low basal *** primary objective of this study was to improve na-MMT platelets separation by organically modifying it with cation and anion exchanges using Cetyl trimethyl ammonium bromide(CTAB)and Sodium dodecyl sulfate(SDS)*** spacing,presence of functional groups,Zetapotential with particle size analysis and thermal stability of the Organomodified na-MMT(OMMT)were characterized using XRD,FTIR,zeta-potential analyzer and TGA *** basal spacing of CTAB modified OMMTincreased to 19.5Åfrom 11.0Åwhich corresponds to the basal spacing of *** SDS modified OMMT did not show any increase in the basal *** spectra of CTAB modified na-MMT illustrated the attachment of CTAB functional groups to na-MMT,while the same was absent in the case of SDS modified *** zeta-potential of na-MMT shifted from–24.88 mV to 15.66 mV in the case of CTAB modified na-MMTand 12.49 mV for SDS modified na-MMT,indicating a greater surface potential of the modified *** TGA showed greater weight loss for CTAB modified na-MMT than that for na-MMT,indicating the effective na+ion exchange with alkyl amines.

关键词： na-MMT CTAB SDS XRD FTIR zetapotential

Effect of cold-working on corrosion induced damage in lug joints

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Defence Technology（防务技术） 2024年第6期36卷 175-182页

作者： Ramanath M.n Chikmath L. murthy h. Department of Aerospace Engineering Indian Institute of Technology-MadrasChennai 600036India Department of Aeronautical Engineering KLS Gogte Institute of TechnologyBelagavi 590008India

Lug joints are preferred joineries for transferring heavy loads to parent components in aerospace *** experience corrosion due to environmental conditions,improper surface finishes and rubbing displacement between the pin and *** causes damage of different sizes and shapes near the *** degradation due to corrosion-induced damage is modelled as a through-pit at one of the identified critical locations through stress *** effect of this pit on fatigue crack initiation life is ***-hole is pre-stressed by cold-working and the benefits of inducing plastic wake on the intended performance of the lug joint during the damages due to corrosion are brought out and compared with non-cold-worked *** analysis is performed on this lug joint with *** results obtained highlight the benefits of cold-working and the methodology can be extended to damage growth and analyse the effect of surface treatments for better structural integrity of components of aerospace vehicles.

关键词： Lug joint Corrosion Crack initiation Cold-working Structural integrity

numerical study on gas production via a horizontal well from hydrate reservoirs with different slope angles in the South China Sea

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Deep Underground Science and Engineering 2024年第2期3卷 171-181页

作者： Tingting Luo Jianlin Song Xiang Sun Fanbao Cheng Madhusudhan Bangalore narasimha murthy Yulu Chen Yi Zhao Yongchen Song School of Mechanics and Civil Engineering China University of Mining and TechnologyXuzhouChina Institute of Rock and Soil Mechanics Chinese Academy of SciencesWuhanChina Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of TechnologyDalianChina Faculty of Engineering and the Environment University of SouthamptonSouthamptonUK

It is important to study the effect of hydrate production on the physical and mechanical properties of low-permeability clayey–silty reservoirs for the largescale exploitation of hydrate reservoirs in the South China *** this study,a multiphysical-field coupling model,combined with actual exploration drilling data and the mechanical experimental data of hydrate cores in the laboratory,was established to investigate the physical and mechanical properties of low-permeability reservoirs with different slope angles during 5-year hydrate production by the depressurization method via a horizontal *** result shows that the permeability of reservoirs severely affects gas production rate,and the maximum gas production amount of a 20-m-long horizontal well can reach186.8 m3/day during the 5-year hydrate *** with smaller slope angles show higher gas production *** depressurization propagation and hydrate dissociation mainly develop along the direction parallel to the ***,the mean effective stress of reservoirs is concentrated in the near-wellbore area with the on-going hydrate production,and gradually decreases with the increase of the slope *** from the effective stress distribution law,the total reservoir settlement amount first decreases and then increases with the increase of the slope *** maximum settlement of reservoirs with a 0°slope angle is up to 3.4 m,and the displacement in the near-wellbore area is as high as2.2 m after 5 years of hydrate *** is concluded that the pore pressure drop region of low-permeability reservoirs in the South China Sea is limited,and various slope angles further lead to differences in effective stress and strain of reservoirs during hydrate production,resulting in severe uneven settlement of reservoirs.

关键词： effective stress low‐permeability reservoirs natural gas hydrate production numerical simulation settlement slope angle the South China

A nano-plasmonic hMIM waveguide based concurrent dual-band BPF using circular ring resonator

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Optoelectronics Letters 2024年第3期20卷 152-156页

作者： Miriyala Sridhar Surendra Kumar Bitra TS n murthy Koppireddi Padmaraju Department of Electronics and Communication Engineering Koneru Lakshmaiah Education FoundationGunturIndia Astra Microwave Products Ltd. HyderabadIndia Department of Electronics and Communication Engineering JNTU-GV College of EngineeringVizianagaramIndia Department of Electronics and Communication Engineering Jawaharlal Nehru Technological University KakinadaKakinadaIndia

This article analyzes the transmission line characteristics of plasmonic hybrid metal insulator metal(hMIM) wave-guide, circular ring resonator(CRR) based dual-band band-pass filters with two transmission poles in both pass-bands in the optical regime using coupled line feed. The transmission line characteristics of an hMIM waveguide, such as characteristic impedance(Z_(PV)), effective refractive index(n_(eff)) and propagation length(L_(spp)), have been obtained by using full wave simulation.

关键词： waveguide resonator circular

Palaeodepositional environment,implications of Glossopteris flora,and organic matter characteristics from the Lower Permian,Karo Open Cast Mine,East Bokaro Coalfield,Damodar Basin,India

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Journal of Palaeogeography 2024年第3期13卷 528-546页

作者： Sankar Suresh Kumar Pillai Rose Ann Sebastian Runcie Paul Mathews Srikanta murthy Anju Saxena Mrutyunjaya Sahoo Suraj Kumar Sahu Gulshan Kumar Dhingra Birbal Sahni Institute of Palaeosciences 53 University RoadLucknow-226007UPIndia Academy of Scientific and Innovative Research(AcSIR) Ghaziabad-201002India Department of Geology School of Earth Science SystemsCentral University of KeralaKasaragod-671316KeralaIndia Department of Geology Ravenshaw UniversityCuttack-753003OdishaIndia Department of Botany Sri Dev Suman Uttarakhand UniversityUttarakhand-249145India

The present study deals with the Early Permian floral diversity,palaeoenvironment,palaeoclimate and depositional setting using a multiproxy approach that includes morphotaxonomy,palynology,and organic geochemistry of Karo OCM(Open Cast Mine),East Bokaro Coalfield,Damodar Gondwana Basin,*** Permian sediments of Peninsular India are widely regarded as fluvial,along with some marine *** macroplant fossil assemblage exhibits the presence of Glossopteridales,comprising Glossopteris,Gangamopteris,and Vertebraria,as well as Coniferales,which includes *** palynological assemblage encompasses the dominance of the striate bisaccate pollen Faunipollenites *** the subdominance of the non-striate bisaccate pollen Scheuringipollenites *** glossopterid *** megafloral and palynofloral assemblage confirms the biostratigraphical age to be Late Barakar palynoflora of Kungurian *** studied morphological characteristics,including small to large Glossopteris leaves exhibiting a lanceolate shape,acute apices,and acute cuneate or tapering bases,as well as entire margins with narrower lamina and narrow meshes,suggest the existence of a dense forest with the prevalence of a warm and humid climate during their *** organic geochemical characterization based on functional group and biomarker analyses reveals the diagenetic effects on organic *** symmetric(~2865-2855 cm^(-1))and asymmetric stretching(~2930-2910 cm^(-1))peaks are identifiable in coal samples,whereas they are absent in carbonaceous *** A-factor vs.C-factor plot suggests that the kerogen type is type Ⅲ,which can generate mainly gaseous *** vitrinite reflectance studies(R_(r) av.1.1%)show increased maturity of the samples,which is supported by the n-alkane distribution pattern and the absence of hopane *** Indian floral assemblages in contemporary of southern Gondwana continents reveal a stronger inclination/affinity with th

关键词： Glossopteris Palynomorph FTIR GCMS Gondwana Permian Palaeoclimate

Evaluation of the microstructure, secondary dendrite arm spacing, and mechanical properties of Al–Si alloy castings made in sand and Fe–Cr slag molds

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International Journal of Minerals,Metallurgy and Materials 2017年第7期24卷 784-793页

作者： I.narasimha murthy J.Babu Rao Department of Metallurgical Engineering Andhra University Visakhapamam 530003 India

The microstructure and mechanical properties of as-cast A356（Al–Si） alloy castings were investigated. A356 alloy was cast into three different molds composed of sand, ferrochrome（Fe–Cr） slag, and a mixture of sand and Fe–Cr. A sodium silicate–CO_2 process was used to make the necessary molds. Cylindrical-shaped castings were prepared. Cast products with no porosity and a good surface finish were achieved in all of the molds. These castings were evaluated for their metallography, secondary dendrite arm spacing（SDAS）, and mechanical properties, including hardness, compression, tensile, and impact properties. Furthermore, the tensile and impact samples were analyzed by fractography. The results show that faster heat transfer in the Fe–Cr slag molds than in either the silica sand or mixed molds led to lower SDAS values with a refined microstructure in the products cast in Fe–Cr slag molds. Consistent and enhanced mechanical properties were observed in the slag mold products than in the castings obtained from either sand or mixed molds. The fracture surface of the slag mold castings shows a dimple fracture morphology with a transgranular fracture nature. however, the fracture surfaces of the sand mold castings display brittle fracture. In conclusion, products cast in Fe–Cr slag molds exhibit an improved surface finish and enhanced mechanical properties compared to those of products cast in sand and mixed molds.

关键词： silica sand ferrochrome slag alloy castings secondary dendrite arm spacing mechanical properties

Synthesis of 4-[F-18]Fluoro-4-Deoxy-n-Acetyl-1,3,6-Tri-O-Acetylglucosamine, a Potential Brain Imaging PET Agent

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natural Science 2024年第3期16卷 19-23页

作者： murthy Akula Derek Cressy Lee Collier George Kabalka Dustin Osborne Department of Radiology The University of Tennessee Medical Center Knoxville USA Advion Biosciences Ithaca USA

The synthesis of a promising brain imaging agent 4-[F-18]fluoro-4-deoxy-n-acetyl-1,3,6-tri-O-acetylglucosamine, 2, was successfully accomplished from commercially available n-acetyl glucosamine in 5 steps. The non-decay corrected radiochemical yield and purity were found to be 31% ± 4% (n = 3) and >98% respectively. The total reaction time for radio labelling step was 50 min.

关键词： n-Acetylglucosamine Amyloidogenesis Lipase-Candida rugosa

Analysis of docosanol using GC/MS:Method development,validation,and application to ex vivo human skin permeation studies

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Journal of Pharmaceutical Analysis 2022年第2期12卷 287-292页

作者： Vijay Kumar Shankar Mei Wang Srinivas Ajjarapu Praveen Kolimi Bharathi Avula Reena murthy Ikhlas Khan Sathyanarayana narasimha murthy Department of Pharmaceutics and Drug Delivery University of MississippiOxfordMS38677USA natural Products Utilization Research Unit Agricultural Research ServiceU.S.Department of AgricultureOxfordMS38677USA national Center for natural Products Research Research Institute of Pharmaceutical SciencesSchool of PharmacyUniversity of MississippiOxfordMS38677USA Topical Products Testing LLC OxfordMS38677USA

Docosanol is the only US Food and Drug Administration(FDA)approved over-the-counter topical product for treating recurrent oral-facial herpes simplex *** analytical methods for docosanol are required to demonstrate the bioequivalence of docosanol topical products.A gas chromatography/selected ion monitoring mode mass spectrometry(GC/SIM-MS)method was developed and validated for docosanol determination in biological *** and isopropyl palmitate(internal standard)were separated on a high-polarity GC capillary column with(88%cyanopropy)aryl-polysiloxane employed as the stationary *** ions of m/z 83 and 256 were selected to monitor docosanol and isopropyl palmitate,respectively;the total run time was 20 *** GC/SIM-MS method was validated in accordance with US FDA guidelines,and the results met the US FDA acceptance *** docosanol calibration standards were linear in the 100-10000 ng/mL concentration range(R^(2)>0.994).The recoveries for docosanol from the receptor fluid and skin homogenates were>93.2%and>95.8%,*** validated method was successfully applied to analyze ex vivo human cadaver skin permeation *** applying Abreva®cream tube and Abreva®cream pump,the amount of docosanol that penetrated human cadaver skin at 48 h was 21.5±7.01 and 24.0±6.95 ng/mg,***,we concluded that the validated GC/SIM-MS was sensitive,specific,and suitable for quantifying docosanol as a quality control *** method can be used for routine analysis as a costeffective alternative to other techniques.

关键词： Docosanol Fatty alcohols Gas chromatography-mass spectrometry Topical formulation Skin permeation

Mechanical behavior of organo-modified Indian bentonite nanoclay fiber-reinforced plastic nanocomposites

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Frontiers of Materials Science 2013年第4期7卷 396-404页

作者： n. RAGhAVEnDRA h. n. narasimha murthy M. KRIShnA K. R. VIShnU MAhESh R. SRIDhAR S. FIRDOSh G. AnGADI S. C. ShARMA Center for Manufacturing and Research Technology Utilization R. V. College Campus Bangalore 560059 Karnataka India Department of Mechanical Engineering R. V. College of Engineering Bangalore 560059 Karnataka India Department of Chemistry ACS College of Engineering Bangalore 560074 Karnataka India Tumkur University Tumkur 572103 Karnataka India

The aim of the research was to examine the influence of organo-modified Indian bentonite （IB） nanoclay dispersed in vinyisster on the mechanical properties of nanoclaylvinylesterlglass nanocomposRes. nanoclay was organically modified using cationic surfactant hexadecyltrimethylammonium bromide （hDTMA-Br） by cation exchange method and dispersed in vinylester using ultrasonication and twin screw extrusion. XRD of nanoclaylvinylester revealed exfoliaUon at 4 wt.% nanoclay indicating uniform dispersion in the polymer. DSC results showed improvement in glass transition temperature by 22.3% in 4 wt.% nanoclaylvinylester/glass when compared with that of vinylester/glass. nanoclay/vinylester/glass with 4 wt,% nanoclay showed 29.23%, 23.84% and 60.87% improvement in ultimate tensile strength （UTS）, fiexural strength （FS） and interlaminar shear strength （ILSS） respectively when compared with those of vinylester! glass. The mode of tensile failure examined by SEM showed no agglomeration of nanoclay in 4 wt.% nanoclayninylester/glass specimens.

关键词： Indian bentonite (IB) ultrasonication twin-screw extrusion mechanical property