quantum dots of cds with hexagonal phase were prepared at relatively low temperature (60 oc) and short time by micro-emulsion (o/w) under ultrasound. this study was focused on the particle size distribution and the growth kinetics. the particle size distribution obtained from the optical absorption edge. it was relatively symmetrical with sonication time. in addition, an agreement was observed ...

soil erosion causes sediments to be detached from their source materials and transported as suspended particles. the present study was conducted to evaluate the effects of sand exploitation on the distribution of suspended sediments in the educational and research forest watershed of tarbiat modares university, which comprises approximately 50,000 ha. fifty-one water samples were collected befo...

the soil water retention curve (swrc) is a basic characteristic of the determination of soil hydraulic properties, including unsaturated hydraulic conductivity. measurement of this curve is essential to research, thus scientists have focused on indirect methods such as pedotransfer functions and empirical relationships to estimate swrc easily. since there is a close relationship between swrc an...

in suspension polymerization, particle size distribution of polymer is the outcome of dynamic equilibrium between the break up and coalescence phenomena. the rates of break up and coalescence and consequently polymerization stability depend on several parameters, the most important of which are type and concentration of stabilizer. in this study, the effects of type and concentration of stabili...

suspension polymerization processes are significantly important in polymer bead formation. one of the important factors for bead size control in these processes is variation in surface tension. in this research, the prediction of optimum concentration of a surface active agent was investigated on the basis of the experimental surface tension diagrams. the experimental data show that the desired...

the arya and paris model is a commonly accepted method to translate a particle-size distribution curve into a corresponding soil moisture characteristic curve using scaling parameter (α). the scaling parameter, in the original model of arya and paris (1981), was assumed constant (α=1.38) for all soil texture classes. in recent years, several studies have shown that α is not constant and its qua...

Gas phase polymerization of propylene was carried out in a semi-batch minireactor using a commercially supported Ziegler–Natta (ZN) catalyst. The influence of variables including monomer partial pressure, external electron donor, reaction temperature and time on the particle morphology and size distribution was investigated. Generally, more uniform fragmentation and particle densities were obta...

tricalcium phosphate as hydroxyapatite is used as a suspension stabilizer in styrene polymerization process. particle size of tcp plays an essential role in the particles’ size distribution and geometrical form of polystyrene products. as the particle size of tcp is reduced, there will be much better chance to engulf the styrene particles. the higher the number of tcp particles surrounding each...