Search for: power-law-correlations
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    Experimental investigation of pulsating heat pipes and a proposed correlation

    , Article Heat Transfer Engineering ; Volume 31, Issue 10 , Oct , 2010 , Pages 854-861 ; 01457632 (ISSN) Shafii, M. B ; Arabnejad, S ; Saboohi, Y ; Jamshidi, H ; Sharif University of Technology
    Pulsating heat pipes are complex heat transfer devices, and their optimum thermal performance is largely dependent on different parameters. In this paper, in order to investigate these parameters, first a closed-loop pulsating heat pipe (CLPHP) was designed and manufactured. The CLPHP was made of copper tubes with internal diameters of 1.8 mm. The lengths of the evaporator, adiabatic, and condenser sections were 60, 150, and 60 mm, respectively. Afterward, the effect of various parameters, including the working fluid (water and ethanol), the volumetric filling ratio (30%, 40%, 50%, 70%, 80%), and the input heat power (5 to 70 W), on the thermal performance of the CLPHP was investigated... 

    Curcumin incorporated PVA-borax dual delivery hydrogels as potential wound dressing materials—Correlation between viscoelastic properties and curcumin release rate

    , Article Journal of Applied Polymer Science ; Volume 135, Issue 45 , 2018 ; 00218995 (ISSN) Rezvan, G ; Pircheraghi, G ; Bagheri, R ; Sharif University of Technology
    John Wiley and Sons Inc  2018
    Poly(vinyl alcohol) (PVA) is a biocompatible polymer which can be physically crosslinked by Borax to form hydrogel. PVA-Borax (PB) hydrogel is a promising candidate for drug delivery system. Therefore, it is necessary to find the quantitative relationship between drug release rate and network structure of PB hydrogels to predict and control drug release rate. In this work, at first step the optimum ratio of Borax: PVA was determined by studying the interactions between PVA chains and Borax molecules by means of Fourier transform infrared spectroscopy, while viscoelastic properties of prepared PB hydrogels were measured in the oscillatory shear flow field. In the following, curcumin as a... 

    Propagation and localization of acoustic and elastic waves in heterogeneous materials: Renormalization group analysis and numerical simulations

    , Article Acta Mechanica ; Volume 205, Issue 1-4 , 2009 , Pages 197-222 ; 00015970 (ISSN) Sahimi, M ; Rahimi Tabar, M. R ; Bahraminasab, A ; Sepehrinia, R ; Vaez Allaei, S. M ; Sharif University of Technology
    We describe and discuss the recent progress in the study of propagation and localization of acoustic and elastic waves in heterogeneous media. The heterogeneity is represented by a spatial distribution of the local elastic moduli. Both randomly distributed elastic moduli as well as those with long-range correlations with a nondecaying power-law correlation function, are considered. The motivation for the study is twofold. One is that recent analysis of experimental data for the spatial distribution of the elastic moduli of rock indicated that the distribution is characterized by the type of long-range correlations that we consider in this study. The second motivation for the problem is to...