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Journal of magnesium and Alloys 2018年第4期6卷 366-374页

作者： C A Niranjan S Srinivas m ramachandra Department of mechanical Engineering BMS College of EngineeringBengaluru-India

In the present study,the influence of dynamic process parameters such as water pressure,traverse speed and abrasive mass flow rate on depth of penetration and surface topography in high strength AZ91 magnesium alloy were investigated using Abrasive Water Jet(AWJ)cutting *** parameters were varied at 3 levels and influences of each parameter on penetration ability were identified using analysis of variance(ANOVA).Contribution of water pressure and traverse speed on jet penetration found higher compared to abrasive mass flow *** projector was used to measure depth of *** features and topography of cut surfaces were examined using Scanning Electron microscopy(SEm).micro cutting and ploughing were observed on the top and bottom portion of the cut which were similar to that of modes of deformation in other ductile materials like aluminium and *** roughness of cut surfaces was measured using Taylor Hobson surface roughness *** roughness found higher at higher traverse speeds and lower at lower traverse *** study also highlights the suitability of AWJ cutting technology for cutting magnesium and its alloys.

关键词： AZ91 magnesium alloy Depth of penetration Profile projector Topography

Erosion corrosion control of 6061 aluminum alloy in multi-phase jet impingement conditions with eco-friendly green inhibitor

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Chinese Journal of Chemical Engineering 2020年第2期28卷 340-347页

作者： m.Lavanya V.ramachandra murthy Padmalatha Rao Department of Biotechnology Manipal Institute of TechnologyManipal Academy of Higher EducationManipalKarnatakaIndia Department of Chemistry Manipal Institute of TechnologyManipal Academy of Higher EducationManipalKarnatakaIndia

Erosion corrosion performance of 6061 aluminum alloy in simulated sea water slurry was investigated under multi-phase jet impingement conditions. The main objective of the work is to study erosion–corrosion of a material with engineering application and mitigate it using eco-friendly green inhibitor. Experiments were performed with the sand concentration of 0.3% and 0.3 μm size. The effect of temperature and flow rate on the performance of inhibitor was explored. Electrochemical methods were adopted for erosion-corrosion measurements. Experiments revealed that starch could mitigate erosion-corrosion with a maximum reduction efficiency of 58% at temperature of 303 K and flow rate of 4 L·min–1. Inhibition efficiency decreased with increase in flowrate and temperature. EIS spectrum demonstrated that the corrosion process in the presence on inhibitor was both charge transfer and mass transfer controlled. A key role of hydrodynamics in the performance of corrosion inhibitor was confirmed by the present study.

关键词： Erosion-corrosion Green-inhibitor Electrochemical studies Aluminum alloy Simulated sea water

Biodiversity and ecological assessments of Indian sacred groves

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Journal of Forestry Research 2014年第1期25卷 21-28页

作者： Rajasri Ray m.D.S.Chandran T.V.ramachandra Energy and Wetland Research Group Centre for Ecological SciencesIndian Institute of Science

Sacred groves are patches of forests preserved for their spiri- tual and religious significance. The practice gained relevance with the spread of agriculture that caused large-scale deforestation affecting bio- diversity and watersheds. Sacred groves may lose their prominence nowadays, but are still relevant in Indian rural landscapes inhabited by traditional communities. The recent rise of interest in this tradition encouraged scientific study that despite its pan-Indian distribution, focused on India＇s northeast, Western Ghats and east coast either for their global/regional importance or unique ecosystems. most studies focused on flora, mainly angiosperms, and the faunal studies concentrated on vertebrates while lower life fomas were grossly neglected. Studies on ecosystem functioning are few although observations are available. most studies attributed watershed protection values to sacred groves but hardly highlighted hydrological process or water yield in comparison with other land use types. The grove studies require diversification from a stereo- typed path and must move towards creating credible scientific foundations for conservation. Documentation should continue in unexplored areas but more work is needed on basic ecological functions and ecosystem dynamics to strengthen planning for scientifically sound sacred grove management.

关键词： biodiversity conservation ecosystem service endemics sacred grove

Cobalt Schiff base complexes: Synthesis characterization and catalytic application in Suzuki–miyaura reaction

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Chinese Journal of Chemical Engineering 2019年第3期27卷 556-563页

作者： Rasheeda m.Ansari Lolakshi K.mahesh Badekai ramachandra Bhat Department of Chemistry Catalysis and Material Chemistry Laboratory National Institute of Technology Karnataka

3-methoxysalicylaldehyde was condensed with the amines 4-aminoacetophenone and 2-amino-5-bromopyridine to obtain Schiff base ligands, 1 and 2, which were coordinated to cobalt salts as complex 1 and complex 2, respectively. The synthesized ligands and complexes were characterized by spectroscopic(FT-IR,UV–Vis,~1H-NmR and mass spectrometry), thermal(TGA) and elemental analysis. The structures of the complexes were verified by evaluating their magnetic susceptibility and spectroscopic evidences. Synthesized complexes were studied for their catalytic activity in the Suzuki–miyaura cross-coupling of aryl halides with phenylboronic acid. Optimized reaction yields 90% of the cyanobiphenyl for complex 1 and 91% for complex 2 with 0.1 mmol of catalyst loading thereby substantiating the C\\C coupling efficiency of the synthesized complexes, 1 and 2.

关键词： Transition metal complex Schiff base Suzuki-miyaura coupling reaction Cobalt

Forest fragmentation and human population varies logarithmically along elevation gradient in Hindu Kush Himalaya-utility of geospatial tools and free data set

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Journal of mountain Science 2017年第12期14卷 2432-2447页

作者： DAS Pulakesh BEHERA mukunda Dev mURTHY manchiraju Sri ramachandra Centre for Ocean River Atmosphere and Land Sciences Indian Institute of Technology Kharagpur International Centre for Integrated mountain Development (ICImOD)

Hindu Kush Himalaya(HKH) is the largest and the most diverse mountain region in the world that provides ecosystem services to one fifth of the total world population. The forests are fragmented to different degrees due to expansion and intensification of human land use. However, the quantitative relationship between fragmentation and demography has not been established before for HKH vis-à-vis along elevation gradient. We used the globally available tree canopy cover data derived from Landsat-Tm satellite to find out the decadal forest cover change over 2000 to 2010 and their corresponding fragmentation levels. Using SRTmderived DEm, we observed high forest cover loss up to2400 m that highly corroborated with the population distribution pattern as derived from satellite observation. In general, forest cover loss was found to be higher in south-eastern part of HKH. Forest fragmentation obtained using ‘area-weighted mean radius of gyration' as indicator, was found to be very high up to 2400 m that also corroborated with high human population for the year 2000 and 2010. We observed logarithmic decrease in fragmentation change(area-weighted mean radius of gyration value),forest cover loss and population growth during 2000-2010 along the elevation gradient with very high R^2 values(i.e., 0.889, 0.895, 0.944 respectively). Our finding on the pattern of forest fragmentation and human population across the elevation gradient in HKH region will have policy level implication for different nations and would help in characterizing hotspots of change. Availability of free satellite derived data products on forest cover and DEm, griddata on demography, and utility of geospatial tools helped in quick evaluation of the forest fragmentation vis-a-vis human impact pattern along the elevation gradient in HKH.

关键词： Tree canopy cover Topography Diachronic analysis Biogeography Human impact

Solid-liquid extraction of Gd(Ⅲ) and separation possibilities of rare earths from phosphoric acid solutions using Tulsion CH-93 and Tulsion CH-90 resins

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Journal of Rare Earths 2012年第12期30卷 1270-1275页

作者： S.Radhika V.Nagaraju B.Nagaphani Kumar m.Lakshmi Kantam B.ramachandra Reddy Inorganic Chemistry Division Indian Institute of Chemical Technology(IICT) Rubamin Limited Halol-389 350India

Solid-liquid extraction of gadolinium was investigated from phosphoric acid medium using commercial amino phosphonic acid resin, Tulsion CH-93. The experimental conditions studied included equilibration time, acid concentration, mass of the resin, metal concentration, loading and elution. The percent extraction of Gd（Ⅲ） was studied as a function of phosphoric acid （0.05-3 mol/L） using Tulsion CH-93 resin. The corresponding lgD vs. equilibrium pH plot gave straight line with a slope of 1.8. The percent extraction decreased with acid co centration increasing, conforming ion exchange mechanism. Under observed experimental conditions the loading capacity of Tulsion CH-93 for gadolinium was 10.6 mg/g. Among several eluants screened, the quantitative elution of Gd（III） from loaded Tulsion CH-93 was obtained with ammonium oxalate （0.15 mol/L）. The extraction behavior of commonly associated metals with gadolinium was studied as a function of phosphoric acid concentration. Tulsion CH-93 resin showed selective extraction towards heavy rare earths （Lu and Yb） which could be separated from other rare earths at 3 mol/L H3PO4, similar to wet phosphoric acid （3-5 mol/L）. On the other hand Gd（Ⅲ） and other rare earths were studied with chelating resin Tulsion CH-90. Light rare earths were highly extracted and these could be separated from heavy rare earths and Gd.

关键词： gadolinium phosphoric acid Tulsion CH-93 Tulsion CH-90 separation factors rare earths

Enhancement of luminescence intensity and spectroscopic analysis of Eu^(3+) activated and Li^+ charge-compensated Bi_2O_3 nanophosphors for solid-state lighting

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Journal of Rare Earths 2019年第4期37卷 356-364页

作者： S.Ashwini S.C.Prashantha ramachandra Naik H.Nagabhushana Department of Physics Channabasaveshwara Institute of Technology Research Center Department of Science East West Institute of Technology Department of Physics New Horizon College of Engineering CNR Rao Center for Advanced materials Tumkur University

The present work reports the synthesis, characterization, photoluminescence and photocatalytic activity of Eu^(3+)(1 mol%-11 mol%) doped and Li^+(0.5 mol%-5 mol%) co-doped Bi_2 O_3 nanophosphors(NPs) by sonochemical method. The average particle size was estimated using powder X-ray diffraction(PXRD)and transmission electron microscopy(TEm) and is found to be in the range of 30-35 nm. The scanning electron microscopy(SEm) images were highly dependent on sonication time and concentration of epigallocatechin gallate(EGCG) bio-surfactant. The energy gap of doped and co-doped Bi_2 O_3 nanophosphors was estimated using Kubelka-munk(K-m) function and is found to be in the range of2.9-3.08 eV. The effect of Li+ co-doping on luminescence of optimized Bi_2 O_3:Eu^(3+) was studied and is found about more than 3 fold enhancement of emission intensity. Judd-Ofelt parameters(Ω_2, Ω_4 and Ω_6).transition probabilities(A_T), quantum efficiency(η), luminescence lifetime(τ_(rad)), color chromaticity coordinates(CIE) and correlated color temperature(CCT) values were estimated from the emission spectra and are discussed in detail. The estimated CIE chromaticity co-ordinates are very close to the NTSC(National Television Standard Committee) standard value of red emission. The synthesized NPs show excellent photocatalytic activity of acid red-88 under UV-light irradiation, which can degrade 98.1% in60 min. The decreasing electron-hole pair recombination rate with quick electron transfer ability is predominantly ascribed to the balance between crystallite size, morphology, band gap, defects, surface area, etc. These results show a light for the use of sonochemical route of Bi_2 O_3:Eu^(3+):Li^+ in solid state display and photocatalytic applications.

关键词： Bi2O3:Eu3+:Li+ Sonochemical Photoluminescence CIE n CCT Photocatalysis Rare earths

POSSIBLE SOLAR INFLUENCE ON ATmOSPHERIC ELECTRIC FIELD

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Advances in Atmospheric Sciences 1988年第2期5卷 217-228页

作者： Poonam Sikka,A.mary Selvam,A.S.ramachandra murty Indian Institute Tropical meteorology Pune-411005 lndia. Indian Institute Tropical meteorology Pune-411005 lndia. Indian Institute Tropical meteorology Pune-411005 lndia.

A physical hypothesis for the electrical coupling of the troposphere, ionosphere and magnetosphere has been proposed. It is shown that the vertical mass exchange takes place in the troposphere, ionosphere and magnetosphere by the gravity wave feedback mechanism through a chain of eddy systems. The vertical mass exchange gives rise to a vertical aerosol current which is responsible for the generation and maintenance of atmospheric electric field and also the variations in the H-component of the geomagnetic field. Any perturbation in the troposphere would be transmitted to ionosphere and vice versa. A global perturbation in ionosphere, as the one caused by solar variability, is transmitted to troposphere influencing weather systems/geomagnetic/atmospheric electrification *** theory relating to the above physical mechanism is discussed. Also, results of analysis of atmospheric electrical field data for Colaba, Bombay (8°53' 56" N, 72° 48' 54" E, 9.8 m ASL) and solar activity indices (Ap index,

关键词： POSSIBLE SOLAR INFLUENCE ON ATmOSPHERIC ELECTRIC FIELD mSB

Experimental study on performance of passive and active solar stills in Indian coastal climatic condition

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Frontiers in Energy 2020年第1期14卷 105-113页

作者： R.LALITHA NARAYANA V.ramachandra RAJU Department of mechanical Engineering Jawaharlal Nehru Technological University(JNTUK)Kakinada533003India Department of mechanical Engineering Rajiv Gandhi University of Knowledge TechnologiesNuzivid521201India

This present work is aimed to examine the effect of mass flow rate on distillate output and performance of a solar still in active *** experiments were conducted at the coastal town,Kakinada(16°93′N/83°33′E),Andhra Pradesh,India.A solar still with a 30°of fixed cover inclination,1 m2 of effective basin area,and a flat-plate collector(FPC)with an effective area of 2 m2 were *** attempt was also made earlier in passive mode to optimize the water depth for the same solar still for maximum yield and distillation *** the passive still,it is observed that the capacity of heat storage and heat drop are significant parameters that affect the still *** the selected still design,the study reveals that 0.04 m water depth is the optimum value for specific climatic *** the active solar still,with the optimum water depth,different flow rates of 0.5,1 and 1.5 L/min are considered through *** is observed that both the mass flow rate and the variation of internal heat transfer coefficients with the mass flow rate have a significant effect on the yield and performance of the *** experimental results show that the combination of 1.5 L/min mass flow rate and an optimum water depth of 0.04 m leads to a maximum yield for the active solar *** enhanced yield of the active solar still is 57.55%,compared with that of the passive solar still,due to increase in area of radiation collection and more heat absorption rate.

关键词： distillation efficiency solar still heat transfer coefficient water depth optimum and mass flow rate

Characteristics of landslide in Koshi River Basin,Central Himalaya

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Journal of mountain Science 2016年第10期13卷 1711-1722页

作者： ZHANG Jian-qiang LIU Rong-kun DENG Wei KHANAL Narendra Raj GURUNG Deo Raj mURTHY manchiraju Sri ramachandra Key Laboratory of mountain Hazards and Surface Process Chinese Academy of SciencesChengdu 610041China Institute of mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China International Centre for Integrated mountain Development KathmanduNepal Central Department of Geography Tribhuvan UniversityKathmanduNepal

Koshi River basin, which lies in the Central Himalayas with an area of 71,500 km2, is an important trans-boundary river basin shared by China, Nepal and India. Yet, landslide-prone areas are all located in China and Nepal, imposing alarming risks of widespread damages to property and loss of human life in both countries. Against this backdrop, this research, by utilizing remote sensing images and topographic maps, has identified a total number of 6877 landslides for the past 23 years and further examined their distribution, characteristics and causes. Analysis shows that the two-step topography in the Himalayan region has a considerable effect on the distribution of landslides in this area. Dense distribution of landslides falls into two regions: the Lesser Himalaya(mostly small and medium size landslides in east-west direction) and the TransitionBelt(mostly large and medium size landslides along the river in north-south direction). Landslides decrease against the elevation while the southern slopes of the Himalayas have more landslides than its northern side. Change analysis was carried out by comparing landslide distribution data of 1992, 2010 and 2015 in the Koshi River basin. The rainfallinduced landslides, usually small and shallow and occurring more frequently in regions with an elevation lower than 1000 m, are common in the south and south-east slopes due to heavy precipitation in the region, and are more prone to the slope gradient of 20°~30°. most of them are distributed in Proterozoic stratum(Pt3ε, Pt3 and Pt2-3) and Quaternary stratum. While for earthquake-induced landslides, they are more prone to higher elevations(2000~3000 m) and steeper slopes(40°~50°).

关键词： Landslide Koshi River Basin Central Himalayas April 2015 Nepal earthquake