In a gas phase %uidized bed ole)n polymerization reactor, it is generally assumed that polymer particles are well mixed and near isothermal reaction conditions prevail. When a highly active Ziegler–Natta catalyst or other type of high activity supported catalyst is used in a gas phase %uidized bed reactor, a certain heterogeneity in the polymer properties is often observed in di4erent size part...

INTRODUCTION Particle size and distribution can influence the properties of materials. This study analyzed and compared the particle size of Root MTA, calcium hydroxide (CH), and a new endodontic cement called calcium enriched material (CEM). MATERIALS AND METHODS The particle size of each material was analyzed three times using 0.05 mg of test material with a particle size analyzer. The part...

Time resolved laser induced incandescence (LII) technique is used to measure size distribution of soot nanoparticles of candle's flame. Pulsed Nd:YAG laser is used to heat nanoparticles to incandescence temperature and the resulting signal is measured. Mass and energy balance equations are numerically solved to calculate temperature of soot particles in low fluence regime. Assuming Plank black ...

Coffee is prepared by the extraction of a complex array of organic molecules from the roasted bean, which has been ground into fine particulates. The extraction depends on temperature, water chemistry and also the accessible surface area of the coffee. Here we investigate whether variations in the production processes of single origin coffee beans affects the particle size distribution upon gri...

In this work, the effects of the scattering angle on the nonexponentiality of the normalized time auto-correlation function of the scattered light intensity g (τ ) are investigated using dilute Poly(N-isopropylacrylamide) microgel and standard polystyrene latex samples in dispersion respectively. The results show that the influences of the scattering angle on the deviation between an exponentia...

An envelope function is derived which multiplies the pair distribution function (PDF) of an infinite solid to obtain that of a spherical particle with the same crystal structure. Distributions of particle sizes are then considered, and the analytical results are used to predict the distribution from a PDF obtained experimentally. The peak broadening for the associated structure factor, expresse...

The characteristics of the particle distribution, evolution and movement in a sonic jet release of carbon dioxide (CO2) from a high pressure reservoir are investigated. The motivation is to numerically model the sonic jet with particles,using the hitherto unknown initial particle distribution measured herein,and hence understand and numerically reproduce the experimentally observedparticle beha...

the nanostructured anatase tio2 with high thermal stability was prepared by polymeric sol-gel method without any additives. the particle size distribution of polymeric titania sol was determined by dynamic light scattering (dls). then properties of obtained titania were investigated by tg-dta, xrd, fesem and tem. also, the decolorization capability of resultant anatase was evaluated using methy...

the effects of temperature, time and the strategy of prepolymerization were studied on the morphology of polypropylene particles. propylene polymerization was carried out in slurry phase using 4th generation of ziegler-natta catalyst, cyclohexylmethyl dimethoxysilane as external electron donor, and triethyl aluminum as co-catalyst. prepolymerizations were carried out based on two strategies: is...