Applicability of the Johnson-Mehl-Avrami (JMA) model was tested based on universal criterion kinetic peak asymmetry. Theoretical simulations were used to prepare variety peaks with different asymmetries, which described by JMA and masterplot function z(α). Based correlation between simulated crystallization description, following intervals degrees conversion corresponding z(α) maxima can be att...

Cluster distribution kinetics is adopted to explore the kinetics of polymer crystallization. Population balance equations based on crystal size distribution and concentration of amorphous polymer segments are solved numerically and the related dynamic moment equations are also solved. The model accounts for heterogeneous or homogeneous nucleation and crystal growth. Homogeneous nucleation rates...

We apply the Hurst exponent idea for investigation of DJIA index time-series data. The behavior of the local Hurst exponent prior to drastic changes in financial series signal is analyzed. The optimal length of the time-window over which this exponent can be calculated in order to make some meaningful predictions is discussed. Our prediction hypothesis is verified with examples of '29 and '87 c...

We study non-isothermal nucleation and growth phase transformations, which are described by a generalized Avrami model for the phase transition coupled with an energy balance to account for recalescence effects. The main novelty of our work is the identification of temperature dependent nucleation rates. We prove that such rates can be uniquely identified from measurements in a subdomain and ap...

Bu çalışmada 7075 Al alaşımı çözeltiye alma ısıl işleminden sonra -40 °C de 2 saat kriyojenik işlem uygulanıp oda sıcaklığında 10 ve 100 gün yaşlandırma işlemi yapılmıştır. Diğer numuneler ise uygulamadan doğal yaşlanma Her numune differential scanning calorimetry (DSC) ile analiz edilmiştir. Analizler sonucu ana mukavemetlenme fazı olarak bilinen yarı kararlı η′ fazının (MgZn2) dönüşüm eğriler...

the purpose of this study is comparison of manganese absorption capacity by natural and modified zeolite. for this purpose used by from semnan mines zeolite with mean particle diameter of 360 micrometer. for modified zeolite, 5 g amount of natural zeolite with 100 ml of 1 m sodium chloride solution mixed and maintained at 24 hours in room temperature. for measure specific surface of absorbents,...

The kinetics of brittle phase transformation in cast duplex stainless steels CD3MN and CD3MWCuN was investigated under continuous cooling conditions. Cooling rates slower than 5 °C/min. were obtained using a conventional tube furnace with a programable controller. In order to obtain controlled high cooling rates, a furnace equipped to grow crystals by means of the Bridgman method was used. Samp...

The aim of this paper is to derive a general theory for the averaging of heterogeneous processes with stochastic nucleation and deterministic growth. We start by generalizing the classical Johnson-Mehl-Avrami-Kolmogorov theory based on the causal cone to hetereogeneous growth situations. Moreover, we relate the computation of the causal cone to a Hopf-Lax formula for Hamilton-Jacobi equations d...

Electrocoagulation (EC) was used for the removal of anthraquinone dye, Alizarin Red S (ARS) from aqueous solution. The process was carried out in a batch electrochemical cell with Al electrodes in a monopolar connection. The effects of some important parameters such as current density, pH, temperature and initial dye concentration, on the process were investigated. Equilibrium was attained afte...