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SUMMARY In the present work, catalytic cracking of fish oil industrial residue was investigated to study the effect of temperature, type of catalyst and the heating rate on the yield of organic liquid fraction (OLF) and its acid value. The highest bio-oil yield of 72% (wt.) was obtained at temperature range of 300-500 °C and heating rate of 10 °C/min with the mixture of Al2O3 and Na2CO3 as a catalyst. It was found that the mixture of Na2CO3 and MgSO4 as a catalyst gives lowest acid value of 8.75 mgKOH/goil and 68.1% of OLF yield. Furthermore, the acid value is reduced to 0.36 mgKOH/goil using Na2CO3 as an absorbent. The results show that the catalytic cracking process represents a sustainable method to produce bio-oil from fish oil industrial residues with physicochemical characteristics similar to the diesel fuel. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A Lagrangian-Eulerian model for the dispersion of solid particles in sudden-expansion flows is reported and validated. The fluid was calculated based on the Eulerian approach by solving the Navier-Stokes equations. A Lagrangian model is also applied, using a Runge-Kutta method to obtain the particle trajectories. The effect of fluid turbulence upon particle dispersion is taken into consideration through a statistical model. The predicted axial mean velocity and turbulent kinetic energy of both phases agree well with experimental data reported by Sommerfield. [ABSTRACT FROM AUTHOR]

In this paper thermal properties of conductive thin films on aluminium substrate are investigated using a phototyhermal method. In the first case the film thermal conductivity and heat capacity, the thermal contact resistance between thin and substrate and the convective heat transfer coefficient are simultaneously estimated. Secondly, the case of anisotropic thin fihns is studied. In that case, axial and radial thermal conductivities and the heat capacity of the thin fihn are simultaneously determined with the convective heat transfer coefficient. For the parameter estimation an inverse technique, based on Levenberg-Marquardt algorithm, is performed. [ABSTRACT FROM AUTHOR]

Knowledge of thermophysical properties is a major challenge to the numerical modeling of heat transfer in liquids. In the present paper, a novel experimental technique is implemented to measure these characteristics. This technique consists on exciting the front face of a three layered sample with a crenel heat flux and measuring the temperature response on the rear face. The three layered sample is formed by a Teflon cell filled with liquid and covered by two copper layers on its front and rear faces. A 1D dimensional model is developed to simulate conductive heat transfer in the sample. The thermophysical parameters are estimated by minimizing the OLS norm referring to the difference between calculated temperatures and the measured signal. This minimization is performed by the Gauss-Newton method. The effective thermal conductivity and the biot number are estimated for two different liquids. The parameter uncertainty is analyzed and a good agreement with literature values is obtained. [ABSTRACT FROM AUTHOR]

Modeling plays an important role in the development of Proton Exchange Membrane Fuel Cell (PEMFC), because it allows a better comprehension of the parameters affecting the fuel performances. PEMFC performances are strongly related to the mechanisms of mass transfer in the stack. The objective of this study is to develop a comprehensive model describing the transport phenomena in the cell and these influences on the fuel performances. First, we present the electrochemical model that takes into account the thermodynamic open circuit voltage and different voltage losses. Second, we present gas diffusion in porous electrodes, water diffusion and electro-osmotic transport through the polymeric membrane. The solutions of the mass transfer equations are used to calculate the fuel cells performances at different operating conditions. [ABSTRACT FROM AUTHOR]

This paper deals with a numerical analysis of the evaporation of a thin binary liquid film by forced convection inside a channel constituted by two parallel plates. The first plate is externally insulated and wetted by a thin water ethylene glycol film while the second is dry and isothermal. The liquid mixture consists of water (the more volatile component) and ethylene glycol while the gas mixture has three components: dry air, water vapour and ethyleneglycol vapour. The set of non linear and coupled equations expressing the conservation of mass, momentum, energy, and species in the liquid and gas mixtures is solved numerically using a finite difference method. Results concerns with the effects of inlet ambience conditions and the inlet liquid concentration of ethylene glycol on the distribution of the temperature, concentrations profiles, and the axial variation of the evaporation rate of species i. [ABSTRACT FROM AUTHOR]

The aim of this work is to study the effect of the addition of a wetting agent to a size solution and to the water used for the pre-wetting to know if it is possible to reduce size content of the yarn with mechanical properties allowing a good ‘weavability’. The effect on the physical and mechanical characteristics of adding the wetting agent was examined. In the tensile test, as a result of adding the wetting agent to a size solution, an increase in the Young modulus of the yarn sized classically was induced, and a decrease with a pre-wetting technique. Concerning the bending rigidity, the same conclusion as for the tensile strength has been demonstrated by using the Kawabata unit. These deteriorations have been explained by using scanning electron microscopy. Indeed, the micrographs seem to show that the fibers of yarns sized with the pre-wetting technique are coated with the size film and not bridged to themselves with the size which explained the decrease of the mechanical properties. However this coating is not recommended in the sizing process. [ABSTRACT FROM PUBLISHER]

A three-dimensional inverse radiation problem of parameter estimation in absorbing, emitting and scattering medium is solved, given temperature profile. The radiative transfer equation is solved by the control volume finite element method (CVFEM) and the Levenberg Marquardt method (LMM) is used to minimize an objective function, expressed by the sum of square residuals between calculated and experimental data. Also, the effects of initial guesses, measurement error and number of measurement points are examined. It is shown that the present technique is robust and can be used to make reliable predictions of the radiative parameters. [ABSTRACT FROM AUTHOR]

This paper presents a novel method for a simultaneous thermal diffusivity estimation of both isotropic layers of a bi-layered composite using a photo-thermal technique. This consists on exposing the bi-layered material on a part of its front face to an irradiation heat flux and recording the temperature rise on the opposite face. The parameter estimation is performed by the minimization of the ordinary least squares objective function comparing the simulated temperature to the response of the mathematical model function of thermo-physical parameters. The used iterative algorithm is based on the Levenberg-Marquardt technique. [ABSTRACT FROM AUTHOR]

The preparation of a warp yarn is a key element of the success of weaving. Under the economic pressure to which the world textile industry is subjected, an increased attention is given to the equipment, to the products and the processes used in the preparation of warp yarns for weaving. The yarn, the sizing equipment and the size must be adapted to each other, so powerful yarns able to resist the weaving requests with lower cost can be obtained. The aim of this work was the study of the mechanical behavior of sized yarns after a pre-wetting operation with hot water and the drying of these yarns on the sizing machine. First, we showed that the heat transfer coefficient was the same, no matter whether the yarn was pre-wetted or not. Pre-wetting did not decrease the production. However, despite containing less size, the yarn hairiness was reduced as compared to sizing without pre-wetting. The initial modulus of sized yarn with pre-wetting was higher than that of classically sized yarn and the sized yarn with this new technology of sizing presented a more important immediate recovery. Moreover, we studied the influence of a preliminary wetting on the structure of the size bridges between fibers by using scanning electron microscopy. Examination of the cross-section of sized yarn showed that if the yarn was pre-wetted, the bridges between fibers could be observed to a higher extent at the periphery of the yarn, which explained the good mechanical behavior. [ABSTRACT FROM AUTHOR]

To assure a real penetration of the enormous intermittent and dispersed naturally renewable resources especially solar and wind, optimal sizing of hybrid renewable power generation systems provide evidence to be indispensable. A determinist technique has been developed to optimize the annual capital cost and the levelized cost of energy of a stand-alone hybrid generation system. Generation and storage units for three systems (wind, photovoltaic, and hybrid photovoltaic-wind turbine) are optimally sized in order to meet the annual load and minimize the capital annualized cost. A case study is conducted to analyze one hybrid project, which is designed to supply residential household located in Monastir city, Tunisia. [ABSTRACT FROM AUTHOR]

This study aims at the preparation of a paraffin/graphite waste composite for thermal energy storage application at low temperature. In this composite material, the paraffin is characterized by high phase change latent heat and graphite serves as the heat transfer promoter. An investigation by means of a Differential Scanning Calorimeter (DSC), a periodic temperature method and a heat storage/release performance unit was conducted in order to measure the phase transition properties, the thermal conductivity and the melting time of the paraffin/graphite waste composites respectively. Experimental results indicated that the melting temperature did not change with the change of the amount of paraffin. On the other hand, the latent heat of phase change material increased with the increasing of the paraffin content. Furthermore, the heat transfer in the composite material during the heat storage process was enhanced through thermal conductivity improvement. [ABSTRACT FROM AUTHOR]

Sizing is a specific finish which makes it possible to confer on warp yarn a mechanical resistance enabling them to support the constraints of weaving without deterioration. This finish must moreover be eliminated at the curl from weaving before the ennoblement and corresponding pollution accounts for practically 50% of the rejections of the dyer. For a few years a technique has appeared which consists in impregnating with water in the warp yarns before sizing them with the size solution. The quantity of size employed is thus reduced but what it happen for the mechanical properties of yarn? it is surprising to note that this pre impregnation leads with less size to products having a better Young modulus and a more important elastic return during fatigue tests. We thus during microscopic examinations could note that these results had with more "spread out" of size points. The physico-chemical tests of characterization showed that this spreading out is due to two parameters: there is a size which is diluted from where a lower viscosity and especially simultaneously we increased the surface tension of yarn by introducing water between fibres from where better wetting. [ABSTRACT FROM AUTHOR]