preparation of tretinoin-containing microspheres with the aim of reducing undesirable skin reactions towards trans retinoic acid (tra) and thus, improving patient compliance is of particular interest. these microspheres have to be smaller than 30 m m to avoid causing gritty feel when applying on the skin, and slow the release of drug to minimize its skin side effects. following preliminary eval...

in this study, liquid-liquid extraction process in a kuhni extraction column was modeled and simulated. a non-equilibrium dynamic model was developed for modeling liquid-liquid extraction processes based on a rate-based model. the model equations are inclusive of partial and ordinary differential equations which were discretized in column height direction. the population balance model was used ...

Mesoporous photocatalysts of CeO2/SBA-15 are prepared by two methods of direct synthesis as solvent-usage and solvent-free methods. In solvent-usage method, CeO2/SBA-15 is synthesized in acidic media. While, in solvent-free method, CeO2/SBA-15, has been prepared through the novel path of directly grind cerium salt into the as-prepared samples of SBA-15 occluded ...

abstract soil drying and rewetting (drw) cycles are considered as environmental stress that would affect the physical, chemical and biological properties of soil and nutrient cycles. the study of soil drying and rewetting effects on plant nutrition and soil fertility is very important and crucial specially their environmental effects. in this study, the effects of 1, 2, 3, 4 and 5 drying and re...

The increasing demand of the low boiling aromatics for chemicals has provided the primary incentive for the tremendous expenditure by the petroleum industry to improve processing methods. Also, refineries are becoming more aware of applying conventional oil refinery processing methods to the production of petrochemicals. Considerable experience has been gained in the operation of certain types ...

Fractionation of plant compounds to produce active purified fractions is a multi-step process, time-consuming and sometimes very expensive. This paper presents a single-step fractionation of tannins from a local plant, Phyllanthus niruri Linn. using supercritical fluid extraction (SFE) method. The effects of operating conditions (pressure, temperature, flow rate, cosolvent content and ethanol-w...

an experimental study has been conducted on the hydrodynamics of a stage mixer-settler to obtain an appropriate design. in this paper several tests was performed to investigate full factorial design of experiments. since each test was repeated seven times, the repeatability of the test was confirmed (p=1 bar and t=25 °c). sauter diameter was determined by photographing both the mixer and settle...

Tailwater recovery systems (TWR) provide an excellent testbed for examining nutrient loading from agriculture non-point sources, such as pre-harvest rice (Oryza sativa L.) field drains, on receiving waters. In this study, the focus was to use continuous sampling of nitrate-nitrogen (NO3−-N) concentration, paired with discrete grab samples of water which were analyzed for total nitrogen and inor...

'Solids formed from coprocessing of 10% coal/90% resid were characterized by solvent extraction, elemental analyses, C'3/C'z isotope ratio, ESR, and GPC techniques. adsorbed petroleum-derived material (oil, resin, asphaltene). The THF insolubles in the product contained high oxygen, low vanadium and a higher level of polyaromatic radicals than the soluble fraction, indicating that these insolub...