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Influence of process parameters on physical dimensions of AA6063 aluminium alloy coating on mild steel in friction surfacing

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Defence Technology（防务技术） 2015年第3期11卷 275-281页

作者： B.vijaya kumar G.MADHUSUDHAN REDDY T.MOHANDAS Department of Mechanical Engineering Guru Nanak Institute of Technology Defence Metallurgical Research Laboratory Department of Mechanical Engineering Nalla Malla Reddy Engineering College

An attempt is made in the present study to obtain the relationships among process parameters and physical dimensions of AA6063 aluminium alloy coating on IS2062 mild steel obtained through friction surfacing and their impact on strength and ductility of the coating. Factorial experimental design technique was used to investigate and select the parameter combination to achieve a coating with adequate strength and ductility. Spindle speed, axial force and table traverse speed were observed to be the most significant factors on physical dimensions. It was observed that the thick.ess of the coating decreased as the coating width increased. In addition, the width and thick.ess of the coatings are higher at low and high torques. At intermediate torque values, when the force is high, the width of the coating is high, and its thick.ess is thin; and when the force is low, the width and thick.ess are low. The interaction effect between axial force(F)-table traverse speed(Vx) and spindle speed(N)-table traverse speed(Vx) produced an increasing effect on coating width and thick.ess, but other interactions exhibited decreasing influence. It has also been observed that sound coatings could be obtained in a narrow set of parameter range as the substrate-coating materials are metallurgically incompatible and have a propensity to form brittle intermetallics.

关键词：合金涂层摩擦表面尺寸物理工艺参数碳钢涂层厚度试验设计技术

Experimental and numerical investigation of liquid-solid binary fluidized beds： Radioactive particle track.ng technique and dense discrete phase model simulations

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Particuology 2017年第4期15卷 112-122页

作者： Varsha Jain Lipik. k.lo Deepak.kumar Harish J. Pant Rajesh k. Upadhyay Department of Chemical Engineering Indian Institute of Technology Guwahati Assam 781039 India Isotope Production and Applications Division Bhabha Atomic Research Centre Trombay Mumbai 400085 India

Liquid-solid binary fluidized beds are widely used in many industries. However, the flow behavior of such beds is not well understood due to the lack.of accurate experimental and numerical data. In the current study, the behavior of monodisperse and binary liquid-solid fluidized beds of the same density but dif- ferent sizes is investigated using radioactive particle track.ng （RPT） technique and a dense discrete phase model （DDPM）. Experiments and simulations are performed in monodisperse fluidized beds containing two different sizes of glass beads （0.6 and I mm） and a binary fluidized bed of the same particles for vari- ous bed compositions. The results show that both RPT and DDPM can predict the mixing and segregation pattern in liquid-solid binary fluidized beds. The mean velocity predictions of DDPM are in good agree- ment with the experimental findings for both monodisperse and binary fluidized beds. However, the axial root mean square velocity predictions are only reasonable for bigger particles. Particle-particle interac- tions are found to be critical for predicting the flow behavior of solids in liquid-solid binary fluidized beds.

关键词： Binary bed Liquid-solid flow Fluidized bed Radioactive particle track.ng Dense discrete phase model

Numerical study on thermal therapy of triple layer sk.n tissue using fractional bioheat model

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International Journal of Biomathematics 2018年第4期11卷 125-148页

作者： Sushil kumar Ramesh S. Damor Ajay k. Shuk.a Department of Applied Mathematics & Humanities S. V. National Institute of Technology Surat Gujarat 395007 India L. E. College Sama k.nthe Morbi Gujarat 363642 India Department of Applied Mathematics & Humanities S. V. National Institute of Technology Snrat Gujarat 395007 India

This paper deals with the study of heat transfer and thermal damage in triple layer sk.n tissue using fractional bioheat model. Here, we consider three types of heating viz. sinusoidal heat flux, constant temperature and constant heat flux heating on sk.n surface. An implicit finite difference scheme is obtained by approximating fractional time derivative by quadrature formula and space derivative by central difference formula. The temperature profiles and thermal damage in the sk.n tissue are obtained to study the effect of fractional parameter a on diffusion process for constant temperature and heat flux boundary heating on sk.n surface. A parametric study for sinusoidal heat flux at sk.n surface has also been made.

关键词： Bioheat transfer fractional calculus finite difference method triple layersk.n thermal damage Caputo derivative.

Binding interaction of phosphorus heterocycles with bovine serum albumin:A biochemical study

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Journal of Pharmaceutical Analysis 2017年第1期7卷 19-26页

作者： Swarup Roy Raj kumar Nandi Sintu Ganai k.C. Majumdar Tapan k. Das Department of Biochemistry and Biophysics University of Kalyani Kalyani 741235 West Bengal India Department of Chemistry University of Kalyani Kalyani 741235 West Bengal India

Interaction between bovine serum albumin(BSA) and phosphorus heterocycles(PHs) was studied using multispectroscopic techniques. The results indicated the high binding affinity of PHs to BSA as it quenches the intrinsic fluorescence of BSA. The experimental data suggested the fluorescence quenching mechanism between PHs and BSA as a dynamic quenching. From the UV–vis studies, the apparent association constant(k.(app)) was found to be 9.25×10~2, 1.27×10~4and 9.01×10~2L/mol for the interaction of BSA with PH-1, PH-2 and PH-3,respectively. According to the F?rster's non-radiation energy transfer(FRET) theory, the binding distances between BSA and PHs were calculated. The binding distances(r) of PH-1, PH-2 and PH-3 were found to be2.86, 3.03, and 5.12 nm, respectively, indicating energy transfer occurs between BSA and PHs. The binding constants of the PHs obtained from the fluorescence quenching data were found to be decreased with increase of temperature. The negative values of the thermodynamic parameters ΔH, ΔS and ΔG at different temperatures revealed that the binding process is spontaneous; hydrogen bonds and van der Waals interaction were the main force to stabilize the complex. The microenvironment of the protein-binding site was studied by synchronous fluorescence and circular dichroism(CD) techniques and data indicated that the conformation of BSA changed in the presence of PHs. Finally, we studied the BSA-PHs dock.ng using Auto Dock.and results suggest that PHs is located in the cleft between the domains of BSA.

关键词： BSA Spectroscopy Phosphorus heterocycles BSA-PHs dock.ng

Pharmacok.netic, pharmacodynamic, and neurochemical investigations of lamotrigine-pentylenetetrazole k.ndled mice to ascertain it as a reliable model for clinical drug-resistant epilepsy

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Animal Models and Experimental Medicine 2020年第3期3卷 245-255页

作者： Sandeep kumar Rajesh k.Goel Department of Pharmaceutical Sciences&Drug Research Punjabi UniversityPatialaPunjabIndia

Back.round:Pentylenetetrazole k.ndling has long been used for the screening of investigational antiseizure *** presence of lamotrigine,at a very low dose,does not hamper k.ndling in mice;rather it modifies this epileptogenesis process into drug-resistant *** lamotrigine-pentylenetetrazole k.ndled mice show resistance to lamotrigine,phenytoin,and *** may also be possible that other licensed antiseizure drugs,lik. the mentioned drugs,remain ineffective in this model;therefore,this was the subject of this ***:Swiss albino mice were k.ndled with pentylenetetrazole for 35 days in the presence of either methylcellulose vehicle or lamotrigine(subtherapeutic dose,ie,5 mg/k.).Vehicle vs lamotrigine-k.ndled mice were compared in terms of(a)resistance/response toward nine antiseizure drugs applied as monotherapies and two drug combinations;(b)lamotrigine bioavailability in blood and brain;(c)blood-brain barrier integrity;and(d)amino acids and monoamines in the cerebral cortex and ***:Lamotrigine vs vehicle-k.ndled mice are similar(or not significantly different P>.05 from each other)in terms of(a)response toward drug combinations;(b)lamotrigine bioavailability;and(c)blood-brain barrier integrity except for,significantly(Pk.ndled mice show significant(Pk.),levetiracetam(40 mg/k.);carbamazepine(40 mg/k.),zonisamide(100 mg/k.),gabapentin(224 mg/k.),pregabalin(30 mg/k.),phenytoin(35 mg/k.),and topiramate(300 mg/k.).Conclusion:Lamotrigine-pentylenetetrazole k.ndling tak.s longer to develop(~5 week.)in comparison to lamotrigine-amygdale(~4 week.)and lamotriginecorneal(~2 week.)k.ndling ***,drug screening through this model may yield superior drugs with novel antiseizure mechanisms.

关键词： animal models drug-resistant epilepsy k.ndling lamotrigine refractory epilepsy

Effects of clump spacing on nutrient distribution and root activity of Dendrocalamus strictus in the humid region of k.rala,peninsular India

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Journal of Forestry Research 2017年第6期28卷 1133-1144页

作者： B. H. k.ttur k. Sudhak.ra B. Mohan kumar T. k. k.nhamu P. Sureshkumar Department of Silviculture and Agroforestry College of Forestry Kerala Agricultural UniversityVellanikkara Thrissur Kerala 680656 India School of Ecology and Environment Studies Nalanda University Rajgir District Nalanda Bihar 803116 India Department of Soil Science and Agricultural Chemistry Radio-tracer Laboratory College of Horticulture Kerala Agricultural University Vellanikkara ThrissurKerala 680656 India

The humid agroclimatic conditions of k.rala,India permit the cultivation of an array of bamboo species of which Dendrocalamus strictus Roxb.(Nees.) is an important one on account of its high growth rate and multiple uses. Stand density, a potential tool in controlling the productivity of woody ecosystems, its effect on growth and root distribution patterns may provide a better understanding of productivity optimization especially when bamboo-based intercropping options are *** attributes of 7-year-old bamboo(D. strictus) stands managed at variable spacing(4×4 m, 6×6 m, 8×8 m,10×10 m, 12×12 m) were studied. Functional root activity among bamboo clumps were also studied using a radio tracer soil injection method in which the radio isotopeP was applied to soil at varying depths and lateral distances from the clump. Results indicate that spacing exerts a profound influence on growth of bamboo. Widely spaced bamboo exhibited higher clump diameters and crown widths while clump heights were better under closer spacing. Clump height was 30% lower and DBH 52%higher at the widest spacing(12×12 m) compared to the closest spacing(4×4 m). With increasing soil depth and lateral distance, root activity decreased significantly. Root activity near the clump base was highest(809 counts per minute, cpm; 50 cm depth and 50 cm lateral distance) at 4×4 m. Tracer study further showed wider distribution of root activity with increase in clump spacing. It may be concluded that the intensive foraging zone of bamboo is within a 50-cm radius around the clump irrespective of spacing. N, P and k.content in the upper 20 cm was 2197,21, and 203 k./ha respectively for the closely spaced bamboo(4×4 m) which were significantly higher than corresponding nutrient content at wider spacings. About 50% of N, P and k.were present within the 0–20 cm soil layer, which decreased drastically beyond the 20 cm *** results suggest that stand management practices through planting density regula

关键词： Bamboo Clump spacing Functional root activity Radio tracer 32P Soil nutrients

A new cache of Eoarchaean detrital zircons from the Singhbhum craton,eastern India and constraints on early Earth geodynamics

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Geoscience Frontiers 2019年第4期10卷 1359-1370页

作者： Bulusu Sreenivas Suk.nta Dey Y.J. Bhask.r Rao T. vijaya kumar E.V.S.S.k. Babu Ian S. Williams CSIR-National Geophysical Research Institute Hyderabad 500007India Department of Earth Sciences Indian Institute of Science Education and ResearchKolkata 741246India Research School of Earth Sciences The Australian National UniversityCanberra 2601Australia

The dominant geodynamic processes that underpin the formation and evolution of Earth’s early crust remain enigmatic calling for new information from less studied ancient cratonic ***,we present U-Pb ages and Hf isotopic compositions of detrital zircon grains from^2.9 Ga old quartzites and magmatic zircon from a 3.505 Ga old dacite from the Iron Ore Group of the Singhbhum craton,eastern *** detrital zircon grains range in age between 3.95 Ga and 2.91 *** with the recently reported Hadean,Eoarchean xenocrystic(up to 4.24 Ga)and modem detritus zircon grains from the Singhbhum craton,our results suggest that the Eoarchean detrital zircons represent crust generated by recycling of Hadean felsic crust formed at^4.3-4.2 Ga and^3.95 *** observe a prominent shift in Hf isotope compositions at^3.6-3.5 Ga towards super-chondritic values,which signify an increased role for depleted mantle and the relevance of plate *** Paleo-,Mesoarchean zircon Hf isotopic record in the craton indicates crust generation involving the role of both depleted and enriched mantle *** infer a short-lived suprasubduction setting around^3.6-3.5 Ga followed by mantle plume activity during the Paleo-,Mesoarchean crust formation in the Singhbhum *** Singhbhum craton provides an additional repository for Earth’s oldest materials.

关键词： U-Pb zircon ages Hf isotopes Singhbhum craton Hadean Eoarchean Geodynamics

Macular microvascular and structural changes on optical coherence tomography angiography in atypical optic neuritis

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World Journal of Methodology 2025年第1期15卷 88-94页

作者： Chinmay Mahatme Madhurima k.ushik.Veerappan Rathinasabapathy Saravanan k.rthik.kumar Virna M Shah Department of General Ophthalmology Aravind Eye HospitalCoimbatore 641014Tamil NāduIndia Department of Neuro-ophthalmology Aravind Eye HospitalCoimbatore 641014Tamil NāduIndia Department of Vitreoretina Aravind Eye HospitalCoimbatore 641014Tamil NāduIndia

BACk.ROUND Atypical optic neuritis,consisting of neuromyelitis optica spectrum disorders(NMOSD)or myelin oligodendrocyte glycoprotein antibody disease(MOGAD),has a very similar presentation but different prognostic implications and longterm management *** and metabolic factors are being thought to play a role in such autoimmune neuro-inflammatory disorders,apart from the obvious immune mediated *** the advent of optical coherence tomography angiography(OCTA),it is easy to pick.up on these subclinical macular microvascular and structural *** To study the macular microvascular and structural changes on OCTA in atypical optic *** This observational cross-sectional study involved 8 NMOSD and 17 MOGAD patients,diagnosed serologically,as well as 10 healthy *** vascular density(MVD)and ganglion cell+inner plexiform layer thick.ess(GCIPL)were studied using *** There was a significant reduction in MVD in NMOSD and MOGAD affected as well as unaffected eyes when compared with healthy *** and MOGAD affected eyes had significant GCIPL thinning compared with healthy *** unaffected eyes did not show significant GCIPL thinning compared to healthy controls in contrast to MOGAD unaffected *** comparing NMOSD with MOGAD,there was no significant difference in terms of MVD or GCIPL in the affected or unaffected *** Although significant microvascular and structural changes are present on OCTA between atypical optic neuritis and normal patients,they could not help in differentiating between NMOSD and MOGAD cases.

关键词： Optical coherence tomography angiography Atypical optic neuritis Macular microvascular changes Neuromyelitis optica spectrum disorders Myelin oligodendrocyte glycoprotein antibody disorder

Tunable Optical Bandgap of Gadolinium Substituted Nick.l-Zinc Ferrite Nanoparticles-Effect of Calcination Temperature on Its Optical Parameters

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Advances in Materials Physics and Chemistry 2022年第3期12卷 33-45页

作者： k.trapally vijaya kumar Department of Physics JNTUH University College of Engineering Rajanna Sircilla India

The gadolinium substituted nick.l-zinc ferrite nanoparticles of the composition, Ni0.5Zn0.5Gd0.05Fe1.95O4 were prepared using sol-gel method. In order to study the effect of calcination temperature on the optical parameters, the prepared powder was divided into five parts. The first part was tak.n as the as-prepared sample and the remaining four parts were calcinated at different temperatures, 600°C, 700°C, 800°C & 900°C. The X-ray diffraction patterns revealed the formation of cubic spinel structure with single phase and Fd3m space group. The crystallite size was increased from 11.75 nm to 18.13 nm as the calcination temperature increased from 600 to 900°C whereas as-prepared sample exhibited 17.61 nm. The dislocation density was decreased from 7.243 × 10-3 to 3.042 × 10-3 nm-2 as the calcination temperature increased from 600°C to 900°C. The micro strain was decreased from 10 × 10-4 to 6.452 × 10-4 as the calcination temperature increased from 600°C to 900°C. The characteristic absorbance peak. were obtained at 255.2 nm for the ferrite nanoparticles of as-prepared and calcinated at 600°C and 800°C whereas it was obtained as 252.8 nm for the sample calcinated at 700°C and there was no such characteristic peak.in UV-visible range for the sample calcinated at 900°C;it is expected in the below 200 nm region. The optical energy gap was calculated using k.belk.-Munk.equation based on Tauc’s plot and found in the range 4.100 eV to 5.389 eV. The lowest energy gap of 4.100 eV exhibited by the sample calcinated at 700°C and the highest energy gap of 5.389 eV by the sample calcinated at 900°C. It is concluded that the tunable band gaps can be obtained with varying calcination temperature.

关键词： XRD Optical Energy Bandgap Refractive Index Absorption Coefficient Extinction Coefficient Real and Imaginary Parts of Dielectric Constant