Репозиторий Университета

Due to the cost efficiency and environmentally friendly surfactant features in enhanced oil recovery techniques, the appropriate designation of surfactant flooding should be considered. It is essential to evaluate the crucial factors that affect surfactant adsorption on rock surfaces to eliminate the total economic losses of surfactant retention and adsorption in porous media. In this paper, the considerable influence of temperature, different surfactant concentrations, and polymer addition were experimentally investigated for dolomite minerals extracted from Pabdeh formation. According to this study, higher adsorption density has occurred at lower temperatures, which implies lower kinetic energy between the surfactant molecules. For 25 ℃, the adsorption density is about 41 mg/g, and it has the lowest value of 100 ℃. It is about 17 mg/g. By the increase of surfactant concentration for different time steps, adsorption density has been increased. For the surfactant concentration of 5 Wt. %, the adsorption density is about 42 mg/g; however, it is for 0.15 Wt. % of surfactant concentration, the adsorption density is about 1 mg/g. Moreover, due to the higher stability of polymers, adsorption density has been decreased by the addition of polymer. The stopping time for each surfactant concentration is about 6.5 h for the surfactant concentration of 5 Wt. %. Consequently, the critical micelle concentration point is about 3.5 Wt. %, 4 Wt. %, and 5 Wt. % for linear alkylbenzene sulfonic acid, cetyl trimethyl ammonium bromide, and Triton X-100, respectively. This change in the conductivity is related to the start of the micelling process by increasing surfactant concentration.

© 2019 Elsevier GmbH Background: The objective of the study was to assess hair trace element and mineral content in children undergoing WFP UN and the governmental programs of school nutrition in Tajikistan. Methods: WFP program included provision or wheat flour fortified with micronutrients including Fe and Zn, and iodized salt, whereas within the governmental program hot meals were provided. A total of 202 children studying in schools that were not (Type 1, n = 100) or were involved in dietary intervention programs (Type 2, n = 102). Food and hair trace element content was assessed using ICP-MS. Results: Daily intake of Fe, I, Zn, B, Co, Mg, Si, and Sr in Type 2 schools was more than 2.5, 12, 4, 2.9, 2.6, 2, 3, and 2-fold higher than that in Type 1 schools. Correspondingly, anthropometric parameters in children from Type 2 schools exceeded the control values. Surprisingly, no significant difference in hair iodine levels was detected. Hair analysis demonstrated a significant increase in hair Ca, Mg, Na, Co, Cr, Cu, Fe, Li, Mn, Se, V, Zn content. Certain toxic elements including Al, As, and Be were also characterized by an increase in Type 2 schools. At the same time, nutritional intervention was associated with a significant decrease in hair B, Hg, and Sn levels. Conclusions: Nutritional intervention within WFP and the governmental program was effective in increasing essential trace element supply in Tajik schoolchildren. However, further studies including a detailed assessment of nutritional and health status with a special focus on iodine and thyroid functioning are required.

© 2018, Pediatria Ltd.. All rights reserved. The article presents data of a systematic review of observational and interventional studies on possible associations between the level of macro-and micronutrients consumption by lactating mothers and their breast milk composition. Authors present the results of a 3-week prospective medical observation in assessing the tolerability of specialized products for lactating mothers, as well as the dynamics of the physical development of their children who are exclusively breastfed.