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Structural,morphological,and optical properties of tin(Ⅳ) oxide nanoparticles synthesized using Camellia sinensis extract: a green approach

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International Journal of minerals,metallurgy and materials 2017年第9期24卷 1043-1051页

作者： J.Celina Selvakumari m.Ahila m.malligavathy D.Pathinettam Padiyan Department of Physics Manonmaniam Sundaranar UniversityTirunelveli 627012Tamil NaduIndia

Tin oxide(SnO) nanoparticles were cost-effectively synthesized using nontoxic chemicals and green tea(Camellia sinensis) extract via a green synthesis method. The structural properties of the obtained nanoparticles were studied using X-ray diffraction, which indicated that the crystallite size was less than 20 nm. The particle size and morphology of the nanoparticles were analyzed using scanning electron microscopy and transmission electron microscopy. The morphological analysis revealed agglomerated spherical nanoparticles with sizes varying from 5 to 30 nm. The optical properties of the nanoparticles’ band gap were characterized using diffuse reflectance spectroscopy. The band gap was found to decrease with increasing annealing temperature. The O vacancy defects were analyzed using photoluminescence spectroscopy. The increase in the crystallite size, decreasing band gap, and the increasing intensities of the UV and visible emission peaks indicated that the green-synthesized SnOmay play future important roles in catalysis and optoelectronic devices.

关键词： tin oxide nanoparticles Camellia sinensis band gap photoluminescence

Setting large-and medium-sized mammal restoration goals in a last mountain Chaco remnant from central Argentina

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Ecological Processes 2023年第1期12卷 301-312页

作者： Daniel Renison Harold Rusbelth Quispe-melgar gAErica Cuyckens Ana mCingolani Centro de Ecología y Recursos Naturales Renovables Dr.Ricardo LutiInstituto de Investigaciones Biológicas y TecnológicasUniversidad Nacional de Córdoba-CONICETAv.Vélez Sarsfield 1611X5016GCA CórdobaArgentina Ecosistemas argentinos 27 de abril 2050CórdobaCórdobaArgentina Facultad de Ciencias de la Salud Universidad ContinentalHuancayoPeru Centro de Estudios Territoriales Ambientales y Sociales(CETAS UNJu)Instituto de Ecorregiones Andinas(INECOAUNJu-CONICET)Alberdi 474600San Salvador de JujuyJujuyArgentina Instituto multidisciplinario de Biología Vegetal CONICET-Universidad Nacional de CórdobaAv.Vélez Sarsfield 1611X5016GCA CórdobaArgentina.

Background Setting large-and medium-sized wild mammal(≥2 kg)restoration goals is important due to their role as ecosystem engineers and generalized numeric ***,determining wild mammal restoration goals is very challenging due to difficulties in obtaining data on current mammal density and due to unclear information on what mammal density values should be used as a *** we chose a 154 ha conservation area within one of the last remnants of the mountainous Chaco from central *** suspected that extensive and unreported defaunation had occurred due to past human pressure and the introduction of non-native *** conduct the analyses,we used a simplified technique that integrates methods used in rangeland and ecological *** Eight native mammal species including only one herbivore species,and four non-native mammal species including three herbivore species were detected during 6113 camera trap *** used known cattle densities as estimated by droppings and direct counts,together with the relative abundance indexes obtained from camera trap photos to calculate the densities of the other species,correcting for mammal *** for the least and most abundant native species were 0.2 and 1.33 individuals km^(-2),respectively;and for non-native species,0.03 and 5.00 individuals km^(-2),*** and non-native species represented 0.8%and 99.2%,respectively,of the bio-mass *** values for native herbivore biomass,as estimated from net primary productivity,were 68 times higher than values estimated for the study area(3179 vs.46.5 kg km^(-2)).Conclusions There is an urgent need to increase native mammals,with special emphasis on herbivore biomass and richness,while non-native mammal numbers must be *** cattle are widespread in large portions of the globe and there is a lot of experience estimating their abundances,the ratio method we used extrapolating from cattle to other large-and medium-s

关键词： Camera trap mammal survey Reference biomass Exotic mammal

Investigation of the Viscoelastic Effect on the metzner and Otto Coefficient Through LDA Velocity measurements

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Chinese Journal of Chemical Engineering 2001年第1期9卷 77-83页

作者： m.Jnhangiri m.R.golkar-Narenji N.montazerin S.Savarmand DepartmentofChemical DepartmentofwmechanicalEngineering AmirkabirUniversityofTechnology（Tehranpolytechnic）No.424HafezAve.Tehran15914I.R.Iran

The metzner and Otto correlation is the single practical method for incorporating non-Newtonian effects in the mixing process. In this article, the metzner and Otto' s idea, the role of viscoelasticity on the metzner and Otto coefficient, ks, effects of flow regime on ks and the determination of fc3 for Rushton turbine impeller have been studied using the direct method of the laser Doppler anemometry (LDA) velocity measurement for the case of viscoelastic liquids. The normalized mean tangential velocity profiles are independent of Rushton turbine impeller speeds. Contrary to literature findings, it is shown that the variation of local shear rate against the impeller speed is better correlated by the power equation, i.e. y= k'a Nb' , in the transition region, i. e. - 30 mproved coefficient, ks', and the elasticity number of viscoelastic liquids is given which is very helpful in designing of the mixing of both viscoelastic and inelastic non-Newtonian fluids through relating rheological properties to kinematical and dynamical parameters of the mixing process.

关键词： viscoelastic mixing Rushton turbine impeller laser Doppler anemometry (LDA) metzner and Otto coefficient

Investigations into the Anti-Felting Properties of Sputtered Wool Using Plasma Treatment

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Plasma Science and Technology 2013年第1期15卷 37-42页

作者： S. m. BORgHEI S. SHAHIDI m. gHORANNEVISS Z. ABDOLAHI Department of Physics Karaj Branch Islamic Azad University Department of Textiles Faculty of Engineering Arak Branch Islamic Azad University Plasma Physics Research Center Science and Research Branch Islamic Azad University

In this research the effects of mordant and plasma sputtering treatments on the crystallinity and morphological properties of wool fabrics were investigated. The felting behavior of the treated samples was also studied. We used madder as a natural dye and copper sulfate as a metal mordant. We also used copper as the electrode material in a DC magnetron plasma sputtering device. The anti-felting properties of the wool samples before and after dying was studied, and it was shown that the shrink resistance and anti-felting behavior of the wool had been significantly improved by the plasma sputtering treatment. In addition, the percentage of crystallinity and the size of the crystals were investigated using an X-ray diffractometer, and a scanning electron microscope was used for morphological analysis. The amount of copper particles on the surface of the mordanted and sputtered fabrics was studied using the energy dispersive X- ray （EDX） method, and the hydrophobic properties of the samples were examined using the water drop test. The results show that with plasma sputtering treatment, the hydrophobic properties of the surface of wool become super hydrophobic.

关键词： anti-felting wool plasma mordant sputtering

Study of structural,electrical and optical properties of vanadium oxide condensed films deposited by spray pyrolysis technique

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Advances in manufacturing 2013年第4期1卷 320-328页

作者： m.mousavi A.Kompany N.Shahtahmasebi m.m.Bagheri-mohagheghi Department of Physics Ferdowsi University of Mashhad Nanoscience Center Ferdowsi University of Mashhad School of Physics Damghan University

Vanadium oxides condensed films are prepared on glass substrates, using spray pyrolysis （SP） technique. The effects of substrate temperature, vanadium concentra- tion in initial solution and the solution spray rate on the nano-structural, electrical, and optical properties of depos- ited films were investigated. Characterizations of the sam- ples were performed using X-ray diffraction （XRD）, scanning electron microscopy （SEm）, and UV-Vis spec- troscopy methods. The type and concentration of the charge carriers were determined and measured by Hall effect experiment. XRD patterns showed that the prepared films had polycrystalline structure, mostly tetragonal fl-V205 and V409 phases with the preferred orientation along （200） direction. The Hall effect experiment revealed that all samples were n-type, except the ones deposited at substrate temperatures Tsub ： 300 ~C and Tsub = 450 ~C, vanadium concentration 0.1 mol/L and solution spray rate 10 mL/min. The charge carrier concentrations obtained were in the range 1016-1018 cm-3. The lowest sheet resistance （R~） was obtained for the samples prepared at T^ub = 450 ~C, vana- dium concentration 0.05 mol/L and solution spray rate 10 mL/min. It was also found that the optical transparency of the samples changed from 20% to 75% and the optical bandgap of the samples was from 2.22 eV to 2.58 eV, depending on the deposition conditions.

关键词： Vanadium oxide Thin films Opticalproperties Spray pyrolysis

Tribological Characterization of Commercial Pure Titanium Processed by multi-Directional Forging

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Acta metallurgica Sinica(English Letters) 2019年第7期32卷 857-868页

作者： I. Ansarian m. H. Shaeri m. Ebrahimi P. minarik Department of materials Science and Engineering Imam Khomeini International University (IKIU) P.O. Box 34148-9681 & Qazvin Iran Department of mechanical Engineering Faculty of Engineering University of Maragheh P.O. Box 55136-533 Maragheh Iran Department of Physics of materials Faculty of Mathematics and Physics Charles University Prague Czech Republic

This work discusses tribological properties of commercial pure (CP) titanium processed by multi-directional forging (mDF) up to six passes at room temperature and 220 ℃. For this purpose, wear test was conducted by dry sliding pin-on-disk method on the initial and ultrafine grained samples using different stress magnitudes of 1, 1.5 and 2 mPa. The results showed that wear resistance of CP titanium increases after the first pass of mDF in comparison with the initial condition, irrespective of the applied normal stress. For example, the average wear rate of mDFed samples was decreased about 30% and 24%, after first pass at room temperature and 220 ℃, respectively. However, average wear rate of the samples processed by six mDF passes was reduced about 40% at lower normal loads;it was increased about 9% at higher ones as compared to the initial condition. It was also found that the dominated wear mechanisms were abrasive and delaminated at the lower stresses, while the delamination mechanism was intensified and a slight adhesion was observed during the higher applied normal loads.

关键词： multi-directional forging Commercial pure titanium Tribological behavior Wear mechanisms

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新生儿神经病学

新生儿神经病学

Prediction and analysis of process failures by ANN classification during wire-EDm of Inconel 718

作者： g.m.·费尼克尔(g.m. Fenichel)

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Advances in manufacturing 2020年第4期8卷 519-536页

作者： Abhilash P.m. Chakradhar D. Department of mechanical Engineering Indian Institute of Technology PalakkadPalakkadKeralaIndia

Wire breakages and spark absence are two typical machining failures that occur during wire electric discharge machining(wire-EDm),if appropriate parameter settings are not *** after several attempts to optimize the process,machining failures cannot be eliminated completely.A n offline classification model is presented herein to predict machining *** aim of the current study is to develop a multiclass classification model using an artificial neural network(ANN).The training dataset comprises 81 full factorial experiments with three levels of pulse-on time,pulse-off time,servo voltage,and wire feed rate as input *** classes are labeled as normal machining,spark absence,and wire *** model accuracy is tested by conducting 20 confirmation experiments,and the model is discovered to be 95%accurate in classifying the machining *** effects of process parameters on the process failures are discussed and analyzed.A microstructural analysis of the machined surface and worn wire surface is *** developed model proved to be an easy and fast solution for verifying and eliminating process failures.

关键词： Wire electric discharge machining(wire-EDm) Process failure Spark absence Wire breakage Artificial neural network(ANN)classification Failure prediction

SHEAR STRESS FOR INITIATION OF mOTION OF NON-UNIFORm SEDImENT mIXTURES

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维普期刊数据库

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International Journal of Sediment Research 2007年第3期22卷 169-179页

作者： Liton Kumar SARKER m. monowar HOSSAIN m. Anisul HAQUE Assis. Engg. Bangladesh Water Development Board (BWDB) Lakshmipur Bangladesh Prof. Department of Water Resources Engineering Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh Prof. Institute of Water and Flood Management (IWFM) Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh

Experiments on initiation of motion of different fractions of non-uniform sediment mixtures are reported. Four sediment mixes and reference transport method to define the threshold of bed particle movement are used in this analysis. Factors controlling the initiation of motion are analyzed. It is found that relative size of different grains with respect to a median size greatly affects the initiation of movement. The incipient motion of non-uniform sediment is very much dependent on the absolute size for coarser fractions. Considering the factors controlling the initiation of motion the experimental data sets along with the other available data yield a new relationship for the calculation of critical shear stress of non-uniform sediments. A set of equations have found that all the data points fall into a single line for the finer and for coarser fractions.

关键词： Non-uniform sediment Critical shear stress Incipient motion Reference shear stress Reference Transport method (RTm)