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Mohamed Rady¹, Eric Arquis²
FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.2, pp. 137-152, 2010, DOI:10.3970/fdmp.2010.006.137
Abstract In the present article, differential scanning calorimetry (DSC) and a modified T-history method have been used to study the phase changing behavior of granular composites. Further modifications and improvements of the two methods are employed to handle granular materials undergoing phase change over a temperature range. A simple procedure has been advised to obtain accurate results from the DSC measurements based on the estimation of the thermal resistance between the sample and its enclosure. The concept of enthalpy and its relationship with temperature has been employed in the T-history analysis to obtain enthalpy-temperature and apparent heat capacity curves similar to… More >

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ARTICLE

Mohsen Ghorbani¹, Hossein Eisazadeh²
FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.2, pp. 153-164, 2010, DOI:10.3970/fdmp.2010.006.153
Abstract Polypyrrole/Poly(vinyl acetate) (PPy/PVAc) copolymer was prepared by the copolymerization of vinyl acetate and pyrrole using FeCl3and benzoylperoxide as an oxidant in the presence of various surfactants such as sodium dodecylbenzenesulfonate and poly(ethylene glycol) in the aqueous/non-aqueous media. The PPy/PVAc copolymer was characterized in terms of conductivity, morphology, chemical structure, particle size and yield. The results indicate that the morphology, particle size, yield and electrical conductivity of the products are dependent on the type of surfactant and the arrangement of monomer injection. The chemical structure of obtained product was determined by FTIR spectroscopy. By comparison FTIR spectra between pure PPy and… More >

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ShadiaJ. Ikhmayies¹, Naseem M. Abu El-Haija¹, Riyad N. Ahmad-Bitar¹
FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.2, pp. 165-178, 2010, DOI:10.3970/fdmp.2010.006.165
Abstract Undoped polycrystalline ZnO thin films were produced on glass substrates at a substrate temperature Ts= 450 C by the spray pyrolysis (SP) technique. The films were characterized by analyzing their I-V curves, transmittance, X-ray diffractograms (XRD) and their scanning electron microscope (SEM) images. The I-V plots are all linear and the resistivity was found to be about 200W.cm. The transmittance in the visible and near infrared regions is as high as 85% which is suitable for solar cell applications. The absorption coefficient which is deduced from the transmittance measurements is continuously increasing with the photon's energy and it rapidly increases… More >

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921

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Leela Rakesh¹, Anja Mueller², Pratik Chhetri¹
FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.2, pp. 179-202, 2010, DOI:10.3970/fdmp.2010.006.179
Abstract A new material for proton conducting membrane with a higher proton transport but reduced water transport is being developed. The new material optimizes proton channel formation, this reducing water transport at the same time. Different proton transporting groups along with different gas flowing channels are examined as well. To meet the goals we design, synthesize, and simulate various proton transporting groups using MD techniques for faster optimization, which in turn helps to synthesize and test only promising structures in the laboratory. At the same time, computer modeling is used to improve the fuel cell system at various operating conditions, specifically… More >

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878

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ARTICLE

A. Benaissa¹, I. Yimer²
FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.2, pp. 203-218, 2010, DOI:10.3970/fdmp.2010.006.203
Abstract This work presents a study on the effect of pulsing on a jet flow. Pulsing is used to modify jet inlet conditions with the objective of improving mixing. In this experimental work, a jet was slightly heated so that temperature could be considered as a passive scalar. The spectral behaviour of velocity and the passive scalar temperature was analyzed along the jet axis with and without pulsing. Low frequency pulsing (f/fS< 0.05 fSthe Strouhal frequency) modifies the spectral composition of the velocity at the jet exit, but it does not affect the asymptotic profile reached in the fully developed region… More >

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838

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Shadia J Ikhmayies¹, Naseem M. Abu El-Haija², Riyad N. Ahmad-Bitar³
FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.2, pp. 219-232, 2010, DOI:10.3970/fdmp.2010.006.219
Abstract Large area and highly uniform polycrystalline ZnO thin films have been produced by a spray pyrolysis (SP) technique resorting to a customized system (spraying) on glass substrates at temperature Ts= 450℃. This study deals with the related investigation about the influence of heat treatment (in nitrogen atmosphere) on the resulting properties (electrical, optical and structural) of such films. Properties are analyzed by means of I-V plots, transmittance curves, X-Ray diffractograms (XRD) and scanning electron microscope (SEM) micrographs. Results show that the resistivity of the films decreases from about 200W.cm for the as-deposited films to about 95W.cm for annealed films. XRD… More >

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