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...

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 ...

the distribution of extracellular enzyme activities in particle-size fractions of sediments was investigated in a subtropical mangrove ecosystem. five enzymes involved in carbon (c), nitrogen (n), and phosphorus (p) cycling were analyzed in the sand, silt, and clay of sediments. among these fractions, the highest activities of phenol oxidase (pho), β-d glucosidase (glu), and n-acetyl-glucosimin...

nano-hydroxyapatite/gelatin (nha/ge) microspheres are currently used in bone tissue engineering as bone filler. in this  study, the effect of fabrication process parameters on the particle size of nano-hydroxyapatite/gelatinmicrospheres was investigated. the nha/ge microspheres were fabricated using water in oil emulsion. in order to design an experimental design, a surface response model with ...

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...

in order to improve particle properties, new processes combining granulation and crystallization are being developed. this work deals with the spherical crystallization process by the quasi-emulsion mechanism applied to carbamazepine, a pharmaceutical drug. the aim of the present study was to produce of spherical grains made of mall crystals of a drug that have adequate properties for direct co...

biofabrication by using fungi is an exciting recent interest to develop an eco-friendly production of metallic nanoparticles (nps) for pharmaceutical applications. this study aimed to synthesize and characterize gold (au) and silver (ag) nps by using penicillium simplisimum. the fungus was grown in fluid czapek dox broth on shaker at 28 ºc and 200 rpm for ten days. then the supernatant was sepa...