نتایج جستجو برای: non isothermal crystallization

تعداد نتایج: 1349859  

2000
F. Ye K. Lu

The crystallization kinetics of an Al89La6Ni5 amorphous alloy were studied by thermal analysis. Both continuous heating and isothermal DSC traces showed that the Al89La6Ni5 amorphous alloy undergoes a two-stage crystallization process upon heating. The ®rst transformation, in which fcc-Al precipitates from the amorphous matrix, is a nucleation and three-dimensional di€usion-controlled growth pr...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2009
mohammad nader lotfollahi

a procedure is presented that synthesizes fractional crystallization separation processes to obtain pure solids from multi-component solutions. the method includes a procedure to generate a network flow model to identify alternative process designs for fractional crystallization. the main advantage of this systematic procedure with respect to other reported procedures is using non-equilibrium s...

2004
Thomas Götz Jens Struckmeier

Recently, Burger and Capasso [M3AS 11 (2001) 1029–1053] derived a coupled system of partial differential equations to describe non–isothermal crystallization of polymers. The system is based on a spatial averaging of the underlying stochastic birth–and–growth process describing the nucleation and growth of single crystals. In the present work we reconsider the scaling properties of the dimensio...

2017
Liyang Yu Emily Davidson Anirudh Sharma Mats R. Andersson Rachel Segalman Christian Müller

Thermal annealing strongly impacts the nano- and microstructure of conjugated polymers. Despite the fundamental importance for the resulting optoelectronic behavior of this class of materials, the underlying crystallization processes have not received the same attention that is encountered in other disciplines of materials science. The question arises whether classical treatment of nucleation a...

Journal: : 2023

The work is devoted to the study of effect an aqueous medium on a polymeric biodegradable material based poly-3- hydroxybutyrate (PHB) by differential scanning calorimetry (DSC). To analyze structural reorganizations polymer, we studied process polymer crystallization after soaking in distilled water. It shown that exposure water, forms exotherms change, rate decreases, and heat decreases insig...

Journal: :polyolefins journal 2016
tao zheng qian li qian zhou huayi li qian xing

9,10-dihydro-9,10-ethano-anthracene-11,12-dicarboxylic acid disodium salt (dheas) was synthesized andused as a nucleating agent for poly(1-butene) (ipb). the isothermal crystallization kinetics of ipb havingdifferent nucleating agents were investigated by differential scanning calorimetry (dsc) and polarized opticalmicroscopy (pom). the results showed that the nucleating agents increased the cr...

2012
Giorgio Flor Amedeo Marini Vittorio Berbenni

a comparison was made between the experimental non-isothermal a vs. t curves and those calculated on the basis of a previous isothermal study. It was observed that for low heating rates, when the "thermal lag" is negligible, the dynamic measurements are in good agreement with the isothermal ones. Furthermore, for process (I), two mathematical methods proposed for the interpretation of the non-i...

Journal: :iranian journal of hydrogen & fuel cell 2015
hassan hassanzadeh seyed hadi golkar

in this paper, a non-isothermal two-phase flow in the cathode gas diffusion layer (gdl) of pem fuel cell is modeled. the governing equations including energy, mass and momentum conservation equations are solved by numerical methods. also, the optimal values of the effective parameters such as the electrodes porosity, gas diffusion layer (gdl) thickness and inlet relative humidity are calculated...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2007
reza ebrahimi kahrizsangi mohammad hasan abbasi ali saidi

the kinetics of molybdenite oxidation was studied by non-isothermal tga-dta with heating rate 5 ºc.min-1.the model-fitting kinetic approach applied to tga data .the coats-redfern method used for model fitting. the popular model-fitting gives excellent fit for non-isothermal data in chemically controlled regime. the apparent activation energy was determined to be about 34.2 kcalmol-1 with pre-ex...

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