• Membrane and Water Treatment
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• v.13 no.4
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• pp.201-208
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• 2022

Emulsion Liquid Membrane (ELM) is a prominent technique for the separation of heavy metal ions from wastewater due to the fast extraction and is a single-stage operation of stripping-extraction. The selection of the components (Surfactant and Carrier) of ELM is a very significant step for its preparation. In the ELM technique, the primary water- in-oil (W/O) emulsion is emulsified in water to produce water-in-oil-in-water (W/O/W) emulsion. The water in oil emulsion was prepared by mixing the membrane phase and internal phase. To prepare the membrane phase, the extractant D2EHPA (di-2-ethylhexylphosphoric acid) was used as a mobile carrier, Span-80 as a surfactant, and Paraffin as a diluent. Moreover, the internal (receiving) phase was prepared by dissolving sulphuric acid in water. Di-(2- ethylhexyl) phosphoric acid such as surfactant concentration, carrier concentration, sulphuric acid concentration in the receiving (internal) phase, agitation time (emulsion phase and feed phase), the volume ratio of the membrane phase to the receiving phase, the volume ratio of the external feed phase to the primary water-in-oil emulsion and pH of feed were studied on the percentage extraction of metal ions at 20℃. The results show that it is possible to remove 78% for As(V), 98% for Cd(II), and 99% for Pb(II). Emulsion Liquid Membrane (ELM) is a well-known technique for separating heavy metal ions from wastewater due to the fast extraction and is a single-stage operation of stripping-extraction. The selection of ELM components (Surfactant and Carrier) is a very significant step in its preparation. In the ELM technique, the primary water-in-oil (W/O) emulsion is emulsified to produce water-in-oil-in-water (W/O/W) emulsion. The water in the oil emulsion was prepared by mixing the membrane and internal phases. The extractant D2EHPA (di-2-ethylhexylphosphoric acid) was used as a mobile carrier, Span-80 as a surfactant, and Paraffin as a diluent. Moreover, the internal (receiving) phase was prepared by dissolving sulphuric acid in water. Di-(2-ethylhexyl) phosphoric acid such as surfactant concentration, carrier concentration, sulphuric acid concentration in the receiving (internal) phase, agitation time (emulsion phase and feed phase), the volume ratio of the membrane phase to the receiving phase, the volume ratio of the external feed phase to the primary water-in-oil emulsion and pH of feed were studied on the percentage extraction of metal ions at 20℃. The results show that it is possible to remove 78% for As(V), 98% for Cd(II), and 99% for Pb(II).

• Membrane and Water Treatment
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• v.14 no.2
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• pp.65-76
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• 2023

Given the limited water resources and the presence of multiple decision makers with different and usually conflicting objectives in the exploitation of water resources systems, especially dam's reservoirs; therefore, the decision to determine the optimal allocation of reservoir water among decision-makers and stakeholders is a difficult task. In this study, by combining a fuzzy VIKOR technique or fuzzy multi-criteria decision making (FMCDM) and the Young's bilateral bargaining model, a new method was developed to determine the optimal quantitative and qualitative water allocation of dam's reservoir water with the aim of increasing the utility of decision makers and stakeholders and reducing the conflicts among them. In this study, by identifying the stakeholders involved in the exploitation of the dam reservoir and determining their utility, the optimal points on trade-off curve with quantitative and qualitative objectives presented by Mojarabi et al. (2019) were ranked based on the quantitative and qualitative criteria, and economic, social and environmental factors using the fuzzy VIKOR technique. In the proposed method, the weights of the criteria were determined by each decision maker using the entropy method. The results of a fuzzy decision-making method demonstrated that the Young's bilateral bargaining model was developed to determine the point agreed between the decisions makers on the trade-off curve. In the proposed method, (a) the opinions of decision makers and stakeholders were considered according to different criteria in the exploitation of the dam reservoir, (b) because the decision makers considered the different factors in addition to quantitative and qualitative criteria, they were willing to participate in bargaining and reconsider their ideals, (c) due to the use of a fuzzy-logic based decision-making approach and considering different criteria, the utility of all decision makers was close to each other and the scope of bargaining became smaller, leading to an increase in the possibility of reaching an agreement in a shorter time period using game theory and (d) all qualitative judgments without considering explicitness of the decision makers were applied to the model using the fuzzy logic. The results of using the proposed method for the optimal exploitation of Iran's 15-Khordad dam reservoir over a 30-year period (1968-1997) showed the possibility of the agreement on the water allocation of the monthly total dissolved solids (TDS)=1,490 mg/L considering the different factors based on the opinions of decision makers and reducing conflicts among them.

• Journal of Veterinary Clinics
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• v.20 no.3
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• pp.286-293
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• 2003

The cardiopulmonary and antagonistic effects of atipamezole, to medetomidine (30 ug/kg, IM)-tiletamine/zolazepam (10 mg/kg, IV) were determined. Twelve healthy mongrel dogs ,(4.00$\pm$0.53 kg, mean$\pm$SD) were randomly assigned to the four experimental groups (control, A30; atipamezole 30 ug/kg, A60; atipamezole 60 ug/kg, A150; atipamezole 150 ug/kg) with 3 dogs in each group. Atropine (0.03 mg/kg, IM), medetomidine, and tiletamine/zolazepam (TZ) were injected 10 minute intervals. Atipamezole was injected intravenously 15 minutes after TZ injection. Mean arousal time (MAT) was 52.50$\pm$4.98, 43.06$\pm$2.60, 32.83$\pm$8.13, and 14.36$\pm$1.60 minutes in control, A30, A60, and Al50 groups respectively. In Al50 group, MAT was significantly reduced (P < 0.05). but mean walking time (MWT) was similar to that in control group. In recovery period, the higher doses of atimapezole, the rougher recovery including head rocking, hypersalivation, and muscle twitching. Five of twelve dogs vomited within 5 minutes after medetomidine injection. In Control group, heart rate significantly decreased in all recording stages except 15 minutes after TZ injection, 10 minutes after medetomidine injection in all groups, and 40 minutes after atipamezole injection in A30 group (P < 0.05). In Al50 group, atipamezole reversed the respiratory depression induced by medetomidine. Arterial blood pressure was significantly decreased 10minutes after medetomidine injection and 15 minutes after TZ injection in almost dogs in this study (P < 0.05). From 10 minutes after atipamezole injection to arousal time, arterial blood pressure was progressively increased in A60 and A150 group. Any value of blood gas analysis and CBC, and serum chemistry values were not significantly changed except pH of Al50 at 10 minutes after medetomidine injection. As shown in present study, atipamezole(150 ug/kg) is considered to exert a useful reversal effect in dogs anesthetized with medetomidine-tiletamine/zolazepam combination.