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Growth of 4＂ diameter polycrystailine diamond wafers with high thermal conductivity by 915 MHz microwave plasma chemical vapor deposition

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Plasma Science and Technology 2017年第3期19卷 93-97页

作者： A F POPOvICH v G RALCHENkO v k BALLA A k MALLIk A A kHOMICH A P BOLSHAkOv D N SOvYk E E ASHkINAZI v Yu YUROv Institute of Radio Engineering and Electronics of Russian Academy of Sciences Fryazino 141190 Russia General Physics Institute of Russian Academy of Sciences Moscow 119991 Russia Harbin Institute of Technology Harbin 150001 People's Republic of China National Research Nuclear University MEPhI Moscow 115409 Russia Central Glass and Ceramic Research Institute Kolkata 700 032 India

Polycrystalline diamond（PCD） films 100 mm in diameter are grown by 915 MHz microwave plasma chemical vapor deposition（MPCvD） at different process parameters,and their thermal conductivity（TC） is evaluated by a laser flash technique（LFT） in the temperature range of230-380 *** phase purity and quality of the films are assessed by micro-Raman spectroscopy based on the diamond Raman peak width and the amorphous carbon（a-C） presence in the *** and increasing dependencies for TC with temperature are found for high and low quality samples,***,as high as 1950 ± 230 W m-1 k-1 at room temperature,is measured for the most perfect material.A linear correlation between the TC at room temperature and the fraction of the diamond component in the Raman spectrum for the films is established.

关键词： thermal conductivity polycrystalline diamond microwave plasma chemical vapordeposition Raman spectroscopy

Convective transport of nanoparticles in multi-layer fluid flow

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Applied Mathematics and Mechanics(English Edition) 2013年第2期34卷 177-188页

作者： k.vAJRAvELU k.v.PRASAD S.ABBASBANDY Department of Mathematics University of Central Florida Department of Mathematics Vijayanagra Sri Krishnadevaraya University Department of Applied Mathematics Imam Khomeini International University

Technologically, multi-layer fluid models are important in understanding fluid-fluid or fluid-nanoparticle interactions and their effects on flow and heat transfer characteristics. However, to the best of the authors＇ knowledge, little attention has been paid to the study of three-layer fluid models with nanofluids. Therefore, a three-layer fluid flow model with nanofluids is formulated in this paper. The governing coupled nonlinear differential equations of the problem are non-dimensionalized by using appropriate fundamental quantities. The resulting multi-point boundary value problem is solved numerically by quasi-linearization and Richardson＇s extrapolation with modified boundary conditions. The effects of the model parameters on the flow and heat transfer are obtained and analyzed. The results show that an increase in the nanoparticle concentration in the base fluid can modify the fluid-velocity at the interface of the two fluids and reduce the shear not only at the surface of the clear fluid but also at the interface between them. That is, nanofluids play a vital role in modifying the flow phenomena. Therefore, one can use nanofluids to obtain the desired qualities for the multi-fluid flow and heat transfer characteristics.

关键词： multi-layer fluid model interaction nanofluid

Structure and floristic composition of old-growth wet evergreen forests of Nelliampathy Hills, Southern Western Ghats

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Journal of Forestry Research 2013年第1期24卷 37-46页

作者： v.S. Ramachandran k. Swarupanandan Forest Ecology and Biodiversity Conservation Division Kerala Forest Research InstitutePeechiThrissur-680653KeralaIndia.

We analyze the structure and composition of old-growth wet evergreen forest of Nelliampathy hills, the chain of hills lying immediately south of Palghat Gap, in the southern Western Ghats of India. We sampled 30 plots of 0.1 ha each （50 m × 20 m） at six locations enumerating all plants ？ 10 cm girth at breast height. We pooled the data and computed various structural parameters. There were 152 species of 120 genera and 51 families of the study area. Of these, 118 （77%） were trees, 24 were climbers （16%） and 10 were shrubs （7%）. Species richness varied from 58–99 per 0.5 ha sample and Shannon indices of diversity ranged from 4.4 to 5.2. Fifty-nine per cent （89 species） of the species were Indian Sub-continent elements and 34% （51 species） are endemic to the Western Ghats. Fifteen species are listed in various threat categories. Aglaia and Litsea were the most species-rich genera. Numbers of families ranged from 27–43 per 0.5 ha sample. Euphorbiaceae and Lauraceae were the most species-rich families. Stand density varied from 1714 to 2244 stems·ha？1 and basal area from 53.6 to 102.1 m2·ha？1. The vegetation was dominated by 3–6 species and six dominance patterns characterized the species composition within the hill complex. The old-growth evergreen forests of Nelliampathy exist as small fragments rich in biodiversity and can be used as benchmarks for comparison with disturbed forests.

关键词： Old-growth evergreen forest Nelliampathy Western Ghats species richness tree density relative abundance stand structure.

Nutrient Recycling from Industrial Solid Wastes and Weeds by vermiprocessing Using Earthworms

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Pedosphere 2013年第5期23卷 668-677页

作者： A. YADAv v. k. GARG Department of Environmental Science and Engineering Guru Jambheshwar University of Science and Technology

vermicomposting is a biotechnological process that enables the recycling of organic waste materials into manure through the combined action of earthworms and mesophilic microorganisms. In this study, a 13-week experiment was carried to vermiprocess food industry sludge mixed with different bedding materials including two weeds, water hyacinth and parthenium, as well as cow dung, in different combinations employing earthworms of the species Eisenia fetida. Eight vermibins containing one kilogram of the waste mixtures （dry weight basis） were established for vermicomposting. vermiprocessing significantly increased nitrogen, phosphorous, and potassium contents of the mixtures. However, a decrease in pH, organic carbon, and C：N ratio was observed after vermiprocessing. The heavy metal contents in the vermicomposts were higher than the initial values but within permissible limits. These results indicated that the studied wastes can be converted into good quality manure by vermiprocessing, which indicated their agricultural values as a soil conditioner if mixed with weeds in appropriate ratios.

关键词： Eisenia fetida food industry sludge heavy metals manure vermicompost

Mathematical modeling on drying of Syzygium Cumini(L.)

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International Journal of Agricultural and Biological Engineering 2013年第4期6卷 96-103页

作者： k.kalaivani v.Chitra Devi Department of Chemical Engineering Kongu Engineering CollegePerunduraiErode-638052TNIndia

In this study,drying characteristics of Syzygium cumini was experimentally investigated under the temperatures of 50°C,60°C and 70°C and the mathematical models were used to fit the drying of Syzygium *** transfered from Syzygium cumini was described by applying the Fick’s diffusion model and the effective moisture diffusivity was *** temperature dependence of the effective moisture diffusivity for the drying of Syzygium cumini samples was described by an Arrhenius-type relationship with activation *** data were fitted to seven drying models,namely Lewis,Henderson and Pabis,Logarithmic,Twoterm,Page,Wang and Singh and modified Henderson and *** Logarithmic model was found as the best fitted model in describing the drying behavior of Syzygium cumini.

关键词： activation energy drying effective moisture diffusivity mathematical model Syzygium cumini

Analysis of Nanof luids as Cutting Fluid in Grinding EN-31 Steel

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Nano-Micro Letters 2011年第4期3卷 209-214页

作者： v.vasu k.Manoj kumar Department of Mechanical Engineering National Institute of Technology

Grinding requires high specific energy which develops high temperatures at wheel work piece interface. High temperatures impair work piece quality by inducing tensile residual stress, burn, and micro cracks. Control of grinding temperature is achieved by providing effective cooling and lubrication. Conventional flood cooling is often ineffective due to enormous heat generation and improper heat dissipation. This paper deals with an investigation on using TRIM E709 emulsifier with Al_2O_3 nanoparticles to reduce the heat generated at grinding zone. An experimental setup has been developed for this and detailed comparison has been done with dry, TRIM E709 emulsifier and TRIM E709 emulsifier with Al_2O_3 nanoparticles in grinding EN-31 steel in terms of temperature distribution and surface finish. Results shows that surface roughness and heat penetration were decreased with addition of Al_2O_3 nanoparticles.

关键词： Grinding Al2O3 nanoparticle Temperature distribution Surface roughness EN-31 steel

Influence of Accompanying Anions on Potassium Retention and Leaching in Potato Growing Alluvial Soils

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Pedosphere 2013年第4期23卷 464-471页

作者： v.SHARMA k.N.SHARMA Department of Soils Punjab Agricultural University

A column study was carried out to assess the influence of accompanying anions on potassium （k） leaching at potato growing sites with different soil textures （sandy loam and clay loam） in northwestern India. Potassium was applied in the top 15 cm layer of soil column at 30 and 60 mg k kg-1 through different sources having different accompanying anions （CI-, SO^-, NO3 and H2PO4-）. Maximum k was retained in the top 0-15 cm layer with a sharp decrease in k content occurring in 15 30 cm layer of the soil column. The trend was similar for both levels of applied k as well as frequency of leaching and soil type. The decrease of k content in soil column after four leaching events was maximum in case of khanaura sandy loam, while only minor decrease was observed in Hundowal clay loam when k was applied at 60 mg k kg-1, indicating higher potential of clay rich soil to adsorb k. In general, the k leaching in presence of the accompanying anions followed the order of SO4^2-≤ H2PO42- 〈 NO3 = Cl-. Highest 1 mol·L^-1 CH3COONH4-extractable k was retained when k was applied along with SO4^2- and H2PO4 anions, and the least was retained when accompanying anion was Cl-. The influence of anions was more pronounced in the light textured soil and at high amounts of k application. Higher levels of k application resulted in higher losses of k, especially in sandy loam soil as observed from the leachate concentration. Among the different k sources, the maximum amount of k leaching was noticed in the soil column amended with kC1. After four leachings, the maximum amount of k leached out was 6.40 mg L-1 in Hundowal clay loam and 9.29 mg L-1 in khanaura sandy loam at 60 mg k kg-1 of soil application through kC1. These concentrations were lower than the recommended guideline of the World Health Organisation （12.00 mg L-1）.

关键词： column study leaching events potassium application potassium sources soil texture

Effect of hydrogen plasma treatment on the growth and microstructures of multiwalled carbon nanotubes

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Nano-Micro Letters 2010年第1期2卷 42-48页

作者： S.k.Srivastava v.D.vankar v.kumar Department of Physics Indian Institute of Technology Delhi National Physical Laboratory Dr.K.S.Krishnan Marg

The effect of hydrogen plasma treatment of iron oxide films on the growth and microstructure of carbon nanotubes(CNTs)by microwave plasma enhanced chemical vapor deposition process has been *** plasma was characterized in-situ using optical emission *** of the films was examined by scanning electron *** analysis was carried out by high resolution transmission electron microscopy(HRTEM)equipped with energy dispersive X-ray spectroscopy(EDS)and micro-diffraction *** is found that oxide films without H_2 plasma pretreatment or treated for lesser time resulted in CNT films with high percentage of carbonaceous particles and with embedded particles/nanorods distributed discontinuously in the cavity of the *** embedded particles were found to be of iron carbide(Fe-C)as confirmed by HRTEM,EDS and micro-diffraction *** observations suggested that the iron oxide particles had poor catalytic action for CNT growth and in-situ reduction of oxide clusters to Fe by hydrogen plasma plays a key role in discontinuous filling of the nanotubes by the catalytic particles.

关键词： Carbon nanotubes Chemical vapor deposition Iron carbide MPECvD

To deformation vector special solution in mining subsidence and ground and rock movements

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中国有色金属学会会刊：英文版 2005年第S1期15卷 294-298页

作者： v. Sedlák P. Blit'an Technical University of koice Faculty of Mining Ecology Process Control & Geotechnologies Institute of Geodesy & GIS Park Komenského 19 SK-04384 Koice SlovakiaTechnical University of Koice Faculty of Mining Ecology Process Control & Geotechnologies Institute of Geodesy & GIS Park Komenského 19 SK-04384 Koice Slovakia

The paper presents some specific procedures in modelling a deformation vector at deformation investigation of various engineering structures, buildings or terrain surfaces which are exposed by abiotik factors, for example by underground mining activities or recent geotectonic movements. A specific problem in deformation measurements is solved, when the same conditions of a monitoring network structure cannot be kept during all periodic observations.

关键词： deformation vector mathematical modelling geodetic periodic monitoring