Browse Items (11858 total)
Sort by:
-
Effect of sonication in enhancing the uniformity of MWCNT distribution in aluminium alloy AA2219 matrix
The present paper investigates the effect of premixing process on the distribution of 0, 0.5, 0.75, 1 and 2 wt.% multiwall carbon nanotubes (MWCNTs) and resultant properties of aluminium alloy AA2219 matrix. Premixing process consists of ultrasonication, magnetic stirring and mechanical stirring. FESEM was used for characterizing the distribution of reinforcement in the matrix. Ball milling with premixing was found to be effective in achieving better uniform distribution of the reinforcement than mere ball milling. Hardness testing of the composite revealed reinforcement of MWCNT enhances the matrix hardness. The thermal stability of composite as evidenced by DTA analysis proved the presence of MWCNT without any structural damages. 2019 Elsevier Ltd. All rights reserved. -
Effect of source-substrate distance on the transparent electrode properties of spray pyrolysed aluminium doped zinc oxide thin films
The wide band gap zinc oxide is a potential metal oxide that has been widely used in optoelectronic applications. The zinc oxide thin films demonstrate excellent conductivity and transparency enabling them for transparent electrode applications. The aluminium doping is an efficient route in further improving the conductivity without compromising the transparency and scalable spray pyrolysis is an effective approach in realizing high quality thin films. Our current study focuses on the effects of distance between the substrate and spray nozzle on the structural, morphological, optical, and electrical properties of aluminium doped zinc oxide. Our results suggests that this spray parameter has appreciable impact on the thin film properties and can be optimized for tuning properties. We explain this in detail backed by the characterization of thin films by X-ray diffraction, Atomic Force Microscopy, UVVis-NIR spectroscopy, Photoluminescence and Hall effect measurements. 2021 -
-
Effect of Substrate Temperature on Properties of Copper Oxide Thin Films Coated by Spray Pyrolysis
Copper oxide shows a wide range of optical as well as electrical characteristics depending upon the preparation parameters. This wide range turning capability makes it a preferable candidate for effective use in various application fields like optical filters, light energy harvesting, gas sensing and semiconducting device fabrication. Spray pyrolysis technique with manual spray system was used to deposit a thin layer of copper oxide on glass substrates at temperatures of 300oC, 350o C, and 400o C. X-ray diffraction analysis shows that all the thin films obtained have monoclinic phase. A change of grain size from 15 nm to 25 nm was observedas the substrate temperature was varied from 300oC to 400o C.The Hall coefficient analysis confirms p-type conductivity in films obtained at 300o C and 350oC and N type conductivity with high resistivity for film coated at 400o C. Optical band gap increases from 1.75 to 2.17 eV with the increase in substrate temperature due to energy band tailing. 2023, Books and Journals Private Ltd.. All rights reserved. -
Effect of substrate temperature on the properties of spray deposited Ga2O3 thin films, for solar blind UV detector applications
In this work, Ga2O3 thin films were deposited on glass substrates by chemical spray pyrolysis technique at three different substrate temperatures 350 C, 400 C, and 450 C. The structural, optical, morphological and electrical characteristics of the deposited sample thin films were investigated. From the studies, it is understood that by tuning substrate temperature, we can extensively change the properties of the film. Optimum temperature for coating Ga2O3 thin films was understood and the work was extended to demonstrate a simple deep UV detector, working in photoconductive mode. The fabricated device exhibit medium response to UV light at 254 nm. The present work report the fabrication of solar blind UV detector based on Ga2O3 thin film, grown using low cost, easily scalable spray deposition technique. 2022 Elsevier B.V. -
Effect of Subtitles on Gaze Behavior during Shot Changes: An Eye-tracking Study; [Efecto de los subtulos en el comportamiento de la mirada durante los cambios de plano: un estudio de seguimiento ocular]
The study provides a comprehensive picture of the effect of subtitles on the gaze behavior of the participants while watching continuity editing and discontinuity editing style cinema. Three video clips (with English subtitles and without subtitles) of continuity editing and discontinuity editing styles were presented to participants. The video clips came from English movies and the participants were not native English speakers. Entry time, dwell time, first fixation time, scan path, and average fixation duration were taken as dependent variables in this within-group study. The eye-tracking data gathered were subjected to repeated measures of two-way ANOVA and paired t-test. Results revealed that the appearance of subtitles at the bottom of the screen changed the eye movement pattern of the participants during the shot changes. Timing of the subtitle starting point (before the cut or after the cut) also affected the gaze behavior. The editing style, however, did not make any difference in the gaze behavior of participants while watching subtitled video clips. Further, participants preferred reading subtitles to seeing visual images even if the subtitles were presented during the shot changes. 2023. International Journal of Psychological Research provides open access to all its contents under the terms of the license creative commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) -
Effect of supercooling on the microstructural development and optimization of physical properties of melt grown SnSe crystals
The microstructural development of stoichiometric tin monoselenide (SnSe) crystals grown by vertical BridgmanStockbarger method using an indigenously fabricated furnace has been investigated under high vacuum (~ 10?6 mbar). The ampoule translation rate (tr) and supercooling, ?T (= Tm ? T, where Tm is the melting point and T is the crystallization temperature) were varied in the range, 122mm/h and 20100C respectively. Enhancement of ?T and tr led to constitutional supercooling, inducing compositional changes and non-stoichiometry. Low ?T (2040C) and high tr (1210mm/h) resulted in globules, flakes and cavities. When ?T = 60C and tr = 9 to 7mm/h, mounds were formed with closed contours and ripples, due to atomically rough liquidsolid (l-?) interface. Fine tuning of ?T (60C) and tr (2mm/h) enabled smooth planar interface, so as to yield good quality crystalline structures with periodic atomic deposition promoting crystal growth, layer-by-layer. Energy dispersive analysis by X-rays and powder X-ray diffraction studies revealed appreciable crystallinity, chemical homogeneity and phase purity. The density of crystals estimated from crystallographic data (6.183g/cm3) corroborates with that obtained utilizing Archimedes principle. Thermogravimetric and microindentation analyses established thermal and mechanical stability. The low etch pit density (~ 102 cm?2) manifests nearly perfect growth of crystals than their melt counterparts. UVVisNIR and PL spectra reflected direct transition with an energy gap of 1.32eV, validating immense potential of the grown crystals for photovoltaic applications. 2019, Springer Science+Business Media, LLC, part of Springer Nature. -
Effect of surface charge and other critical parameters on the adsorption of dyes on SLS coated ZnO nanoparticles and optimization using response surface methodology
Adsorption is a possible method with distinct advantages to remediate pollution due to dyes. Sodium Lauryl Sulfate (SLS) coated ZnO nanoparticles were synthesized using the electrochemical method. The final product was dried at different temperatures, 60, 120, 150 and 300 C. The sample dried at 60 C was found to have the maximum SLS coating on its surface providing high negative charge density. This facilitates the adsorption of cationic dyes on its surface through electrostatic attraction. The effect of SLS on the adsorption process was confirmed by comparing it with ZnO without SLS. The effect of important parameters such as amount of adsorbent, concentration of dye, temperature and time on the percentage of adsorption was investigated using Box-Behnken design (BBD) of Response Surface Methodology (RSM). The prepared catalysts were characterized using X-ray diffraction analysis, infrared spectroscopic analysis, scanning electron microscopy, elemental detection analysis, thermogravimetric and zeta potential analysis. Finally, the study was extended to Langmuir and Freundlich isotherms in order to confirm the type of adsorption. The adsorption kinetics studies showed that it obeys pseudo second order kinetics. 2020 Elsevier Ltd. -
-
Effect of temperature modulation on Rayleigh-Benard convection in a rotating layer of a ferromagnetic fluid
The stability of a rotating horizontal layer of ferromagnetic fluid heated from below is examined when, in addition to a steady temperature difference between the walls of the layer, a time-dependent sinusoidal perturbation is applied to the wall temperatures. Only infinitesimal disturbances are considered. The effects of the oscillating temperature field are treated by a perturbation expansion in powers of the amplitude of the applied field. The onset criterion is derived when the condition for the principle of exchange of stabilities is valid. The shift in the critical Rayleigh number is calculated as a function of the frequency of modulation, magnetic parameters, Taylor number and Prandtl number. The effect of various parameters is found to be significant for moderate values of the frequency of modulation. It is shown that, when the thermal excitation is symmetric, supercritical motion is more pronounced for low Prandtl number ferro fluids. Further, for the case in which only the bottom wall temperature is modulated, the effect of rotation is to stabilize the system at low frequencies and the opposite is true for moderately large frequencies. The problem throws light on external means of controlling convection in ferromagnetic fluid applications. -
Effect of Temperature on Electrical Properties of Reduced Graphene Oxide (rGO)/Li-ion Embedded Flexible Solid Polymer Electrolyte Films
Reduced graphene oxide (rGO) was synthesized from graphite powder by modified Hummers method. The rGO is emerged with Polystyrene sulfonic acid/Lithium phosphate to prepare PL-rGO solid polymer electrolyte films. The electrical properties of Polystyrene sulfonic acid/Lithium phosphate/reduced graphene oxide composites were analyzed, which is an essential property to obtain the performance, reliability and lifetime of battery with respect to temperature. The mass and charge transfer process that takes place at the interface of electrode and electrolyte was obtained by Impedance analyzer. The Nyquist plots were plotted in the frequency range 1 Hz-35 MHz at different temperatures (30-100OC). The ionic conductivity of PL-rGO polymer electrolyte is 1.4x10-3 S/c.m has been observed for the composition PSSA/Li3PO4/rGO::50:45:05 wt%. The conductivity of PL-rGO composites is directly related to temperature. The hopping of the ions in the PL-rGO is observed by using dc conductivity which follows the Arrhenius relationship. 2019 Elsevier Ltd. -
Effect of temperature/gravity modulation on the onset of magneto-convection in electrically conducting fluids with internal angular momentum
The effect of time-periodic temperature/gravity modulation on the onset of magneto-convection in electrically conducting fluids with internal angular momentum is investigated by making a linear stability analysis. The results of the present study are presented against the background of the results of weak electrically conducting fluids. The qualitative findings of Siddheshwar and Pranesh are found to be true in the present case also except that the eigenvalue is found to be magnitudewise less than that obtained in the case of a weak electrically conducting fluid. -
Effect of temperature/gravity modulation on the onset of magneto-convection in weak electrically conducting fluids with internal angular momentum
The effect of time-periodic temperature/gravity modulation at the onset of magneto-convection in weak electrically conducting fluids with internal angular momentum is investigated by making a linear stability analysis. The Venezian approach is adopted in arriving at the critical Rayleigh and wave numbers for small amplitude temperature/gravity modulation. The temperature modulation is shown to give rise to sub-critical motion and gravity modulation leads to delayed convection. An asymptotic analysis is also presented for small and large frequencies. 1999 Elsevier Science B.V. -
Effect of the Process Parameters on Machining of GFRP Composites for Different Conditions of Abrasive Water Suspension Jet Machining
The selection of parameters for abrasive water suspension jet (AWSJ) machining of GFRP composites is a major aspect to be considered for optimizing the process. Generally, machining of plastics, polymer matrix composites are accomplished by the AWSJ machining carried out in the presence of atmospheric air; however, the existence of air around the AWSJ may lead to expansion of jet which results in increase in the kerf width and surface roughness; thus to overcome this drawback, an effort has been made in the current work to compare the effect of different process parameters on kerf width and surface roughness while using AWSJ techniques for machining glass fibre-reinforced plastic composite submerged in water. The exploratory outcomes have herewith validated the fact that the surface roughness and kerf width diminishes in under water machining when contrasted with that of free air machining; this is majorly attributed to the fact that the jet diameter reduces in under water AWSJ machining, thereby reducing the kerf width and surface roughness for optimized values of the parameters of speed, feed and standoff distance. Further, the experimental trials have clearly shown that the AWSJ machining used with an optimized set of parameters yields better machining capabilities as compared to abrasive water jet machining. 2019, King Fahd University of Petroleum & Minerals. -
Effect of Transaction Costs on Portfolio Management
Zenith International Journal of Multidisciplinary Research, Vol-3 (7), pp. 115-126. ISSN-2231-5780 -
Effect of treated and untreated domestic sewage water irrigation on tomato plants
Background and Objectives: Agricultural cultivations in the world are suffering from water shortages. Water scarcity poses challenges in the economy and health of people all over the world. The present study aimed the cultivation of tomato plants using groundwater, treated and untreated domestic sewage water and tried to make a comparative study on the heavy metals present in the leaves and fruits of the tomato plants. Materials and Methods: The water samples were analyzed for various physicochemical parameters such as; pH, total hardness, chloride, total alkalinity, dissolved oxygen and heavy metal. Stomatal conductance was measured using porometer. The heavy metal analysis was conducted using Atomic Absorption Spectrometer. Results: All physicochemical parameters were found to be below the permissible level of standard values in the groundwater and treated domestic sewage water, but above the permissible level in untreated domestic sewage water. Stomatal conductance was found to be very low in the plants treated with untreated domestic waste water (296.33/428 in the ventral surface during the morning and noon, respectively) when compared to the leaves of the plants treated with other water samples. Untreated domestic sewage water showed a very high level of lead, i.e., 7.5354 ppm, whereas the treated sewage water contained 0.5650 ppm slightly above the permissible level. Conclusion: The present study has revealed that the treated domestic sewage water would be used for the irrigation of agricultural cultivation. 2020 Jobi Xavier and Akhil K. Varghese. -
Effect of tungsten oxide thin films deposited on cerium oxide nano rods for electrochromic applications
Cerium oxide Nanorods were synthesized on Fluorine-doped Tin Oxide (FTO) coated glass substrate by hydrothermal process. Optimized Tungsten Oxide (WO3) films were coated on the top of cerium oxide (CeO2) Nanorods by a sputter deposition method. WO3 thin film was deposited at a constant substrate temperature of 300K under partial pressures of oxygen (ppo2) at 8 10?4 mbar. X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), UVVisible spectrometer, and cyclic voltammetry were used to analyse the films for material, optical, surface, and electrochemical properties. The improved CeO2/WO3 films increased the cathodic peak current which is related to their high active surface area and increased H+ ions intercalation in the films. In addition, the CeO2 Nanorods/WO3 hybrid films had a better electrochemical property in terms of the diffusion coefficient of 5.53 10?8 cm2/s. These structures produce considerable coloration efficiency when compared to pure WO3 (9.88, 10.19 and, 8.14 cm2/C at 700 nm). This study predicts that how varying concentrations of cerium oxide Nano rods change WO3 electrochemical behaviour which will help to choose the right rare earth elements and concentrations for energy-efficient smart windows. 2022 -
Effect of vacancies on thermopower of molybdenum disulfide monolayers
A detailed theoretical investigation of the effect of scattering of electrons and phonons by lattice vacancies in molybdenum disulfide (MoS2) monolayers (MLs) on diffusion, S d, and phonon-drag, S g, components of thermoelectric power (TEP), S, is presented over a wide-temperature range (1 < T < 300 K) using the Boltzmann transport formalism. The diffusion component is assumed to be influenced, not only by vacancies via short-range and Coulomb disorder scattering, but also by charged impurities (CIs) and acoustic and optical phonons. In the case of S g, the phonons are considered to be scattered, besides the vacancies, by sample boundaries, substitutional isotopic impurities, as well as other phonons via both N- and U-processes. Numerical calculations of S d and S g, as functions of temperature and vacancy defect density are presented for MoS2 MLs with n s = 1017 m-2 supported on SiO2/Si substrates. The role of carrier scatterings by mono-sulfur and mono-molybdenum vacancies in influencing the overall electron and phonon relaxation rates and in determining S d and S g are investigated. The behavior of S d and S g is found to be noticeably influenced by vacancy scattering. The influence on S d is seen to be more for mono-sulfur vacancies for densities lesser than 1%. The influence, is to enhance S d slightly for MLs with realizable CI concentrations. On the other hand, S g is found to depend sensitively on the vacancy disorder for T < 50 K; a S-vacancy density of 0.1% is found to suppress the characteristic peak of S g by almost 60%. The extent of reduction in the characteristic peak of S g, observable in low temperature measurements of S, can provide information about defect density. The calculations demonstrate that defect engineering of MoS2 ML systems can be used to tune their thermoelectric performance. A need for detailed experimental studies is suggested. 2018 IOP Publishing Ltd. -
Effect of variable viscosity on marangoni convective boundary layer flow of nanofluid in the presence of mixed convection
The effect of variable viscosity on Marangoni convection in immediate vicinity of the plate is discussed. The mathematical model of the problem is highly nonlinear partial differential equations transforms into two nonlinear ordinary differential equations by applying suitable similarity transformations. The reduced similarity equivalences are then solved numerically by RungeKutta Fehlberg-45 order method. The consequences of pertinent parameters like variable viscosity parameter, convection parameter and volume fraction are analyzed on various flow fields. The results acquired are on par with erstwhile published results. The results of the present study shows that for greater values of angular momentum the buoyancy effects dominate, augmentation in mixed convection carries away the free convection currents from the plate, increase in volume fraction of solid enhances the thermal conductivity of the fluid and it is important to note that Marangoni effect is constructive for cooling processes. 2019 by American Scientific Publishers All rights reserved. -
