Showing 2 results for S. M. Mousavi
S. M. A. Razavi, S. A. Mortazavi, S. M. Mousavi,
Volume 10, Issue 2 (summer 2006)
Abstract
In this study, the effect of transmembrane pressure (TMP) on flux decline and protein rejection due to concentration polarization and fouling (adsorption) resistances during ultrafiltration of reconstituted skimmilk was investigated. UF experiments were carried out using a pilot plant unit equipped with spiral wound module and polysulfonamide UF membrane. A three-stage experimental strategy based on a resistance-in-series model (boundary layer-adsorption) was used to seperately determine the hydraulic membrane resistance, concentration polarization and fouling resistances. The results showed that increasing TMP had no effect on initial flux reduction (Jrt), but flux decline in each TMP was greatly due to concentration polarization, and fouling has a small role in flux decline, whereas dynamic response of flux decline proved that increasing Jrt during operation is due to fouling. The influence of TMP on resistances showed that total hydraulic resistance and reversible fouling resistance are increased with increasing TMP, but intrinsic membrane resistance and irreversible fouling resistance did not change. Increasing the total hydraulic resistance with time resulted in increasing both reversible and irreversible fouling resistances. Increasing TMP or operation time had no significant effect on protein rejection, but only led to an increase about 1-4 percent.
S. M. Mousavi, A. Hoshmand, S. Bromandnasab, M. Yazdani,
Volume 16, Issue 60 (Summer 2012)
Abstract
The common method of irrigating rice in paddy fields of Iran, like most countries, is flooded irrigation. The water required in this method is too much. However, because of water shortage in recent years, and malfunctioning of irrigation systems, it is needed to use water in a reasonable way and increase water use efficiency. Therefore, it is necessary to know water loss amounts at the paddy fields. The deep percolation (DP) was measured by closed- and open-bottom rings in 4 locations, and 7 sites at each location, of paddy fields in Somae-Sara city, Guilan province. These locations were selected on the base of different physiographic units. The average DP of these locations was also monitored during plant growth season. The measurements were performed twice a week. Results showed that the rate of DP varied during the season, and could take a positive or negative value. The most important factors of these variations were the lateral seepage (from surrounding rice fields) and the high perched groundwater table in paddy fields.
