Free surface planar liquid jet impingement on a moving surface: interfacial flow and heat transfer characteristics

Journal of Mechanical Science and Technology - Understanding heat transfer characteristics of sheet metal is of practical importance in sheet metal rolling operation to ensure strength and quality...     

Towards an ontology based framework for searching multimedia contents on the web

Multimedia Tools and Applications - We live in a world where there are huge number of consumers and producers of multimedia content. In this sea of information, finding the right content is like...     

Impedance spectroscopy and dielectric properties of Ce and La substituted Pb0.7Sr0.3(Fe0.012Ti0.988)O3 nanoparticles

We present the structural, microstructural, dielectric and impedance behavior of Pb_0.7Sr_0.3[(Fe_2/3Ce_1/3)_0.012Ti_0.988]O₃ (PSFCT) and Pb_0.7Sr_0.3[(Fe_2/3La_1/3)_0.012Ti_0.988]O₃ (PSFLT) nanoparticles. These nanoparticles were prepared by a chemical synthesis route using polyvinyl alcohol as surfactant. The X-ray diffraction pattern shows polycrystalline nature with coexistence of tetragonal and cubic phase in both PSFCT and PSFLT nanoparticles. The average particle size has been measured using Scherer's relation. The average particle sizes also measured by TEM are 10 and 11 nm, and by SEM 9 and 12 nm, respectively, of PSFCT and PSFLT nanoparticles. By measuring the value of relative permittivity (?′) and loss (tan δ) at lower frequency, the dielectric properties show Maxwell-Wagner type interfacial polarization. However, due to nano size effect of PSFCT and PSFLT, dispersionless dielectric response has been observed up to higher frequency of 15 MHz. The frequency dependent real (Z′) and imaginary (Z″) parts of impedance confirmed the variation which was observed in dielectric properties. The values of resistance of grain boundaries, R_gb is higher than grains, R_g indicates that the effect of grain boundaries is dominant on electrical properties when the size of nanoparticles is quite small.     

Magnetoelectric,Raman, and XPS Properties of Pb0.7Sr0.3[(Fe2/3Ce1/3)0.012Ti0.988]O3 and Pb0.7Sr0.3[(Fe2/3La1/3)0.012Ti0.988]O3 Nanoparticles

The Pb_0.7Sr_0.3[(Fe_2/3Ce_1/3)_0.012Ti_0.988]O₃ (PSFCT) and Pb_0.7Sr_0.3[(Fe_2/3La_1/3)_0.012Ti_0.988]O₃ nanoparticles were prepared by chemical synthesis route using polyvinyl alcohol as surfactant. X-ray diffraction pattern has been used to analyze the phase structure and average particles size. The phase structure is also confirmed by Raman spectra. The chemical states of Pb²⁺, Sr²⁺, Fe³⁺; Ti⁴⁺, Ce³⁺, La³⁺, and oxygen ions have been analyzed by X-ray photoelectron spectroscopy. The magnetoelectric coupling effect is confirmed by magnetic phase transition near ferroelectric phase-transition temperature. The magnetoelectric effect is also confirmed by measuring the value of magnetoelectric coefficient (α _E) as the function of applied dc magnetizing field under the influence of ac magnetic field of 10 Oe and frequencies of 847 and 997 Hz. The higher value of α _E is observed in PSFCT sample.     

Measurements of effective diffusion coefficients of helium and hydrogen through gypsum

An experimental apparatus, which was based on the ¼-scale garage previously used for studying helium release and dispersion in our laboratory, was used to obtain effective diffusion coefficients of helium and hydrogen (released as forming gas for safety reasons) through gypsum panel. Two types of gypsum panel were used in the experiments. Helium or forming gas was released into the enclosure from a Fischer burner¹ located near the enclosure floor for a fixed duration and then terminated. Eight thermal-conductivity sensors mounted at different vertical locations above the enclosure floor were used to monitor the temporal and spatial gas concentrations. An electric fan was used inside the enclosure to mix the released gas to ensure a spatially uniform gas concentration to minimize stratification. The temporal variations of the pressure difference between the enclosure interior and the ambience were also measured. An analytical model was developed to extract the effective diffusion coefficients from the experimental data.     

Contrast enhancement via texture region based histogram equalization

Abstract

This paper presents two novel contrast enhancement approaches using texture regions-based histogram equalization (HE). In HE-based contrast enhancement methods, the enhanced image often contains undesirable artefacts because an excessive number of pixels in the non-textured areas heavily bias the histogram. The novel idea presented in this paper is to suppress the impact of pixels in non-textured areas and to exploit texture features for the computation of histogram in the process of HE. The first algorithm named as Dominant Orientation-based Texture Histogram Equalization (DOTHE), constructs the histogram of the image using only those image patches having dominant orientation. DOTHE categories image patches into smooth, dominant or non-dominant orientation patches by using the image variance and singular value decomposition algorithm and utilizes only dominant orientation patches in the process of HE. The second method termed as Edge-based Texture Histogram Equalization, calculates significant edges in the image and constructs the histogram using the grey levels present in the neighbourhood of edges. The cumulative density function of the histogram formed from texture features is mapped on the entire dynamic range of the input image to produce the contrast-enhanced image. Subjective as well as objective performance assessment of proposed methods is conducted and compared with other existing HE methods. The performance assessment in terms of visual quality, contrast improvement index, entropy and measure of enhancement reveals that the proposed methods outperform the existing HE methods.     

Nonplanar dust acoustic solitary and rogue waves in an ion beam plasma with superthermal electrons and ions

The propagation characteristics of dust acoustic solitary and rogue waves are investigated in an unmagnetized ion beam plasma with electrons and ions following kappa-type distribution in nonplanar geometry. The reductive perturbation method(RPM) is employed to derive the cylindrical/spherical Korteweg–de Vries(KdV) equation, which is further transformed into standard KdV equation by neglecting the geometrical effects. Using new stretching coordinates,nonlinear Schr?dinger equation(NLSE) has been derived from the standard KdV equation to study the different order rational solutions of dust acoustic rogue waves(DARWs). The impact of various physical parameters on the characteristics of dust acoustic solitary waves(DASWs) is elaborated specifically in nonplanar geometry. Further, the effects of ion beam and superthermality of electrons/ions on the characteristics of DARWs are studied. The results obtained in the present investigation may be useful in comprehending a variety of phenomena in Earth's magnetosphere polar cap region where the presence of positive ion beam has been detected and also in other regions of space/astrophysical environments where dust along with superthermal electrons and ions exists.     

Thermoelectric rectification in a graphene-based triangular ballistic rectifier (G-TBR)

A four-terminal ballistic rectifier demonstrating voltage rectification for both electrical (AC/DC) as well as thermal (temperature gradient) inputs is presented. The thermoelectric behavior of the graphene triangular ballistic rectifier (G-TBR) is based on its nonlinear electrical response. The responsivity and noise equivalent power of the device are calculated to be 8870 mV/W and 1.59 nW/Hz^1/2, respectively, at a back-gate voltage of 5 V. The rectified thermal voltage between two isothermal output (lower and upper) terminals is estimated to be 2.8 µV at a temperature gradient of 150 K. Further, the electric and thermoelectric output of the proposed G-TBR is validated by analytical modeling. Such G-TBRs could be used in the future in energy harvesting application to use heat produced by electronic circuitry, integrated circuits (ICs), etc.