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اطلاعات انتشار: Iranian Journal of Chemistry and Chemical Engineering (IJCCE)، بيست و نهم،شماره۲(پياپي ۵۴)، ۲۰۱۰، سال ۰
تعداد صفحات: ۸
Two N4–type Schiff base ligands named N,N'–bis(2–pyridylmethylidene)–1,2–diiminoethane (L1) and N,N'–bis(2–pyridylmethylidene)–1,3–diiminopropane (L2) have been synthesized by the reaction of pyridine–2–carbaldehyde with ethylenediamine and propylenediamine, respectively. The binding abilities of L1 and L2 in dichloromethane towards Cu2+, Cd2+, Co2+, Ni2+, Zn2+ and Pb2+ ions were evaluated by performing competitive extraction experiments on the mixtures containing theses ions from aqueous picrate and nitrate media as a function of the aqueous phase pH. The results show a pronounced selectivity of the ligands towards copper and cadmium ions among the tested metal ions. It is shown that the copper\cadmium selectivity of the ligands is profoundly influenced by the nature of anions accompanying the extracted complexes. In fact, the ligands are more efficient complexing agent for cadmium ions in the presence of nitrate and acetate anions, whereas this selectivity changes towards copper ions in the presence of picrate, perchlorate and thiocyanat ions.
اطلاعات انتشار: Iranian Journal of Chemistry and Chemical Engineering (IJCCE)، سي ام،شماره۳(پياپي ۵۹)، ۲۰۱۱، سال ۰
تعداد صفحات: ۱۴
A Real–Time Optimization (RTO) strategy incorporating the fuzzy sets theory is developed, where the problem constraints obtained from process considerations are treated in fuzzy environment. Furthermore, the objective function is penalized by a fuzzified form of the key process constraints. To enable using conventional optimization techniques, the resulting fuzzy optimization problem is then reformulated into a crisp programming problem. The crisp programming problem is solved using both Sequential Quadratic Programming (SQP) and Heuristic Random Optimization (HRO) techniques for comparison purposes. The proposed fuzzy RTO strategy is demonstrated via the Tennessee Eastman benchmark process, and is also compared with a crisp RTO strategy from the literature. Remarkable economical improvement is found over the crisp RTO. In spite of the fuzzified constraints, the proposed strategy yields smooth operation of the process, while maintaining the product quality within the acceptable range.
اطلاعات انتشار: Caspian Journal of Environmental Sciences، نهم،شماره۱، ۲۰۱۱، سال ۰
تعداد صفحات: ۱۰
The chromosomal spread and karyotype of Bleak (Alburnus alburnus) from Anzali lagoon were identified using tissue squashing techniques with injection of 0.5ml\100g body weight of 0.01% Colchicines solution in fish fingerlings. Kidney and gill tissues were then extracted and chopped in KCl 0.045M for 20 min and fixed in Carnoy solution in 3 stages. The chromosomal spreads were stained in 20% Gimsa for 30 min. From 347 chromosomal spread counts, the results showed diploid chromosome number of this species2n=50. Karyotype composed of 7 metacentric, 13 submetacentric and 5 acrocentric or subtelocentric choromosome pairs, and the number of chromosome arms (NF) was determined as NF=90
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