Comparison of the effect of carbon,halloysite and titania nanotubes on the mechanical and thermal properties of LDPE based nanocomposite films

In this study, titania nanotubes(TNTs) were prepared by hydrothermal method with the aim to compare the properties of these one-dimensional tubular nanostructures' reinforced nanocomposites with the carbon and halloysite nanotubes'(CNTs and HNTs, respectively) reinforced nanocomposites. Low density polyethylene(LDPE) was used as the matrix material. The prepared nanocomposites were characterized and compared by means of their morphological, mechanical and thermal properties. SEM results showed enhanced interfacial interaction and better dispersion of TNTs and HNTs into LDPE with the incorporation of a MAPE compatibilizer,however, these interactions seem to be absent between CNTs and LDPE, and the CNTs remained agglomerated.Contact angle measurements revealed that CNT filled nanocomposites are more hydrophilic than HNT composites, and less than TNT composites. CNTs provided better tensile strength and Young's modulus than HNT and TNT nanocomposites, a 42% increase in tensile strength and Young's modulus is achieved compared to LDPE.Tear strength improvement was noticed in the TNT composites with a value of 35.4 N·mm~(-1), compared to CNT composites with a value of 25.5 N·mm~(-1)·s~(-1). All the prepared nanocomposites are more thermally stable than neat LDPE and the best improvement in thermal stability was observed for CNT reinforced nanocomposites.CNTs depicted the best improvement in tensile and thermal properties and the MAPE compatibilizer effectiveness regarding morphological. mechanical and thermal properties was only observed for TNT and HNT systems.     

Development and characterization of conductive ring spun hybrid yarns

Development of conductive yarns for smart textile applications is the most demanding area of research these days. This study was aimed to investigate the effect of yarn constructional parameters, and relative humidity on electromechanical properties of conductive ring spun hybrid yarns. Stainless steel (SS) fibre was blended with polyester and viscose fibre separately on 12% and 24% weight basis to produce hybrid conductive yarns at three different levels of twist factor. The electromechanical properties of yarns were evaluated in response to change in blend type, blend ratio, twist factor, and relative humidity. The content of SS fibre is found to be more effective followed by the twist factor and blend type to govern the linear electrical resistance (LER) of conductive yarns. In addition, on increasing relative humidity, the LER of viscose stainless steel (VS) hybrid yarns are found to drop significantly than that of polyester stainless steel (PS) hybrid yarns.     

Aliovalent Ho3+ ion doped BaZrO3 thin films; Structural,optical and photoluminescence properties

Ho doped BaZrO3 thin film phosphors with varying Ho content (1, 2, 3 and 4?at%) were prepared via pulsed laser deposition technique. To understand the effect of doping on structural, morphological, optical and emission properties of thin films, X-ray Diffractrometer (XRD), Scanning Electron Microscopy (SEM), Spectroscopic Ellipsometry (SE) and Photoluminescence (PL) Spectroscopy have been used, respectively. Polycrystalline nature with single phase cubic crystalline structure of the films has been obtained. The optical band gap energy, as estimated by SE, has been found to increase with increase in the Ho content. The PL spectra of the synthesized phosphor exhibit green and yellow-orange as prominent emission bands in response to 328?nm as excitation wavelength.     

Kinetics of internal steam reforming of methane on Ni/YSZ-based anodes for solid oxide fuel cells

The kinetics of steam reforming of methane was determined on a Ni-YSZ anode, which we refer to as anode ‘A’ and on a Ni-YSZ anode modified by the addition of a basic compound, which we refer to as anode ‘B’. A salient feature of our work is that the data were collected on 50 μm thick anodes screen-printed on 110 μm thick YSZ electrolytes and the experiments were carried out in a fuel cell configuration. Orders in methane and steam were both higher on the modified Ni-YSZ anode. Activation energy was also higher on this anode suggesting different nature of sites in the two anodes. In the present study we have attempted to generate kinetic data at steam/carbon ratios which are economically attractive for fuel cell operation.     

Lightly supervised alignment of subtitles on multi-genre broadcasts

This paper describes a system for performing alignment of subtitles to audio on multigenre broadcasts using a lightly supervised approach. Accurate alignment of subtitles plays a substantial role in the daily work of media companies and currently still requires large human effort. Here, a comprehensive approach to performing this task in an automated way using lightly supervised alignment is proposed. The paper explores the different alternatives to speech segmentation, lightly supervised speech recognition and alignment of text streams. The proposed system uses lightly supervised decoding to improve the alignment accuracy by performing language model adaptation using the target subtitles. The system thus built achieves the third best reported result in the alignment of broadcast subtitles in the Multi–Genre Broadcast (MGB) challenge, with an F1 score of 88.8%. This system is available for research and other non–commercial purposes through webASR, the University of Sheffield’s cloud–based speech technology web service. Taking as inputs an audio file and untimed subtitles, webASR can produce timed subtitles in multiple formats, including TTML, WebVTT and SRT.     

Split-step Adams–Moulton Milstein methods for systems of stiff stochastic differential equations

In this paper we discuss new split-step methods for solving systems of Itô stochastic differential equations (SDEs). The methods are based on a L-stable (strongly stable) second-order split Adams–Moulton Formula for stiff ordinary differential equations in collusion with Milstein methods for use on SDEs which are stiff in both the deterministic and stochastic components. The L-stability property is particularly useful when the drift components are stiff and contain widely varying decay constants. For SDEs wherein the diffusion is especially stiff, we consider balanced and modified balanced split-step methods which posses larger regions of mean-square stability. Strong order convergence one is established and stability regions are displayed. The methods are tested on problems with one and two noise channels. Numerical results show the effectiveness of the methods in the pathwise approximation of stiff SDEs when compared to some existing split-step methods.     

Solution blow spinning of piezoelectric nanofiber mat for detecting mechanical and acoustic signals

Solution blow spinning (SBS) technique can produce nanofibers (NFs) mat in large-scale production. In this work, the SBS was used to fabricate piezoelectric polyvinylidene fluoride (PVDF) NF membranes that can be utilized for energy harvesting applications. The effect of operating air pressure from (2–5 bar) on the surface morphology of the NFs has been studied. The structural analysis for crystalline polymorph β-phase for PVDF powder, casted film, electrospinning and SBS NFs has also been presented with the aid of Fourier-transform infrared spectroscopy and X-ray diffraction (XRD). Piezoelectric characteristics of PVDF NFs mats were tested by applying impact impulse with different weights from different heights between 1 and 10 cm. The sensitivity of the voltage response increased from 1.71 mV/g to 8.98 mV/g, respectively. Besides, the SBS generated PVDF mat is found to be sensitive to pressure forces in a range of few Newtons with the generated voltage according to detected sensitivity of 80 mV/N based on the analysis of the impact of a few Hertz mechanical vibrations. In addition, the produced SBS NFs were applied as an acoustic signal detector within different acoustic frequencies. The results suggest that the β-phase PVDF nanofibrous membrane produced via the SBS technique has a great potential to be used as a piezoelectric sensor.     

First and second law investigation of waste heat based combined power and ejector-absorption refrigeration cycle

In the proposed cogeneration cycle, a LiBr-H₂O absorption refrigeration system is employed to the combined power and ejector refrigeration system which uses R141b as a working fluid. Estimates for irreversibilities of individual components of the cycle lead to possible measures for performance improvement. Results of exergy distribution of waste heat in the cycle show that around 53.6% of the total input exergy is destroyed due to irreversibilities in the components, 22.7% is available as a useful exergy output, and 23.7% is exhaust exergy lost to the environment, whereas energy distribution shows 44% is exhaust energy and 19.7% is useful energy output. Results also show that proposed cogeneration cycle yields much better thermal and exergy efficiencies than the previously investigated combined power and ejector cooling cycle. Current investigation clearly show that the second law analysis is quantitatively visualizes losses within a cycle and gives clear trends for optimization.     

Unmixing functional magnetic resonance imaging data using matrix factorization

Functional magnetic resonance imaging (fMRI) data is processed by different techniques for detection of activated voxels including principal component analysis (PCA), independent component analysis (ICA), non‐negative matrix factorization (NMF), and so on. In this work, a modified version of NMF method is proposed in which data is not supposed to be non‐negative. The proposed scheme is applied to synthetic fMRI data along with NMF conventional method. The results of the proposed scheme show that it is not only computationally efficient but also has good quality results as compared to that of NMF in terms of average correlation. Finally, proposed method is applied to monkey's fMRI data, and the results are compared with that of NMF and ICA. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 195–199, 2012     

Parallel Rosenbrock methods for chemical systems

Parallel Rosenbrock methods are developed for systems with stiff chemical reactions. Unlike classical Runge-Kutta methods, these linearly implicit schemes avoid the necessity to iterate at each time step. Parallelism across the method allows for the solution of the linear algebraic systems in essentially Backward Euler-like solves on concurrent processors. In addition to possessing excellent stability properties, these methods are computationally efficient while preserving positivity of the solutions. Numerical results confirm these characteristics when applied to problems involving stiff chemistry, and enzyme kinetics.