modelling the catalyst fragmentation pattern in relation to molecular properties and particle overheating in olefin polymerization

Modelling the catalyst fragmentation pattern in relation to molecular properties and particle overheating in olefin polymerization

A two-dimensional single particle finite element model was used to examine the effects of particle fragmental pattern on the average molecular weights, polymerization rate and particle overheating in heterogeneous Ziegler-Natta olefin polymerization. A two-site catalyst kinetic mechanism was employed together with a dynamic two-dimensional molecular species in diffusion-reaction equation. The i...

identifying the strategies persian efl learners use in reading an expository text in english and examining its relation to reading-proficiency and motivation: a think-aloud study

هدف اصلی از این مطالعه بررسی نوع و میزان استراتژی هایی بود که دانشجویان فارسی زبان رشته ی زبان انگلیسی در حین خواندن یک متن انگلیسی به کار گرفتند. این مطالعه همچنین به بررسی تفاوت های استراتژی های مورد استفاده بین دارندگان سطح بالا و پایین درک مطلب پرداخت. نوع همبستگی بین استراتژی به کار گرفته و درک مطلب از یک سو و استراتژی به کار گرفته و انگیزه از سوی دیگر نیز در این تحقیق مورد آزمایش قرار گرف...

efl teachers job satisfaction and social capital in relation to students’ motivation

abstract this mixed method study examines whether there is any relationship among the variables of the study (job satisfaction, social capital and motivation). the researcher considered job satisfaction and social capital as independent variables; motivation is the dependent variable of the study. the researcher applied a questionnaire to assess each variable. to measure efl teachers’ job sati...

: examining l2 teachers’ corrective feedback types in relation to learners’ uptake, proficiency levels, and context types

abstract this study investigates the teachers’ correction of students’ spoken errors of linguistic forms in efl classes, aiming at (a) examining the relationship between the learners’ proficiency level and the provision of corrective feedback types, (b) exploring the extent to which teachers’ use of different corrective feedback types is related to the immediate types of context in which err...

FI Catalyst for Polymerization of Olefin

Mathematical modeling the effect of catalyst initial shape and the crack pattern in olefin copolymerization

A two-dimensional (2D) single particle model for the copolymerization of propylene-ethylene with heterogeneous Ziegler-Natta catalyst is developed. The model accounts for the effects of the initial shape of the catalyst and carck/ pore patterns on the copolymer composition, polymerization rate and the average molecular weight properties. The spherical and oblate ellipsoidal shapes of catalyst p...