Design and Optimization of Heat Integrated Distillation

Process integration is currently considered as the main trend to improve process performance, and is one of the major approaches to reduce the annual operating and capital costs in the plant. For distillation systems, heat integration technique provides such an approach to improve the traditional simple column sequences. This work presents the optimization of distillation column sequences based on creation of maximum possible heat integration and minimizing the total annual cost of process. All the optimum simple sequences and possible heat integrated sequences are designed and considered to find the best heat integrated sequence with the minimum total annual cost. Sequences are simulated and the objective function is modeled. Basic operation parameters of sequences are changed according to the process constraints to find all the possible heat integration and minimize the objective function. The best structures with the minimum total annual cost are designed and compared for the considered industrial case study. Results show the height percent of optimization of process costs by the internal heat recovery of integration.Key words: Distillation; Sequence; Modeling; Integration; Optimizatio

Study of Ziegler-Natta/(2-PhInd)2ZrCl2 hybrid catalysts performance in slurry propylene polymerization

Several types of hybrid catalysts are made through mixing of 4th generation Ziegler-Natta (ZN) and (2-PhInd)2ZrCl2  metallocene catalysts using triethylaluminum (TEA) as coupling agent. Response surface methodology (RSM) is used to evaluate the interactive effects of different parameters including amounts of metallocene and TEA and temperature on metallocene loading. Analyzing the amounts of Al and Zr elements in the hybrid catalysts through ICP-OES and EDXA reveals that temperature plays a crucial role on anchoring of the metallocene catalyst on ZN while TEA has the least determining effect. The ICP analysis shows that as the concentration of Al goes up in the hybrid catalyst the concentration of Zr passes a maximum, while EDXA shows a direct relationship between the Al and Zr contents. Using triisobutylaluminum (TIBA) and methylaluminoxane (MAO) as the coupling agents, almost similar metallocene loadings are observed. Finally, the performance of hybrid catalysts is investigated in propylene polymerization and the obtained polymers are characterized using DSC and DMTA through which the presence of two types of polymers in the final product are confirmed

The impact of individual and group_based expectations on the self_image and reading comprehension of iranian intermediate efl learners

The study scrutinized the effect of individual and group-based expectations on EFL learners' self-image and reading comprehension. This study explored the effectuality of individual expectations and group-based expectations in improving self-image and reading comprehension among EFL learners. To do so, 50 out of 120 Iranian EFL learners were chosen as the sample of the study and they were divided into two groups of Individual-based Expectation Instruction and Group-based Expectation Instruction, received five sessions of instruction along with some types of expectations and took two types of reading and self-image tests as a pre- and post-test. In general, the results showed no significant difference between the two groups’ mean scores on the post-test of self-image. The results revealed that the individual expectation group significantly outperformed the group-based expectation group on the post-test of reading comprehension. The findings suggest that using different forms of expectations in language classes can be instrumental in improving the students’ self-image and reading comprehension.O estudo examinou o efeito das expectativas individuais e baseadas em grupo na autoimagem dos alunos de EFL e na compreensão de leitura. Este estudo explorou a efetividade das expectativas individuais e expectativas baseadas em grupo na melhoria da autoimagem e compreensão de leitura entre alunos de EFL. Para fazer isso, 50 de 120 alunos de EFL iranianos foram escolhidos como a amostra do estudo e eles foram divididos em dois grupos de Instrução de Expectativa baseada no Individual e Instrução de Expectativa baseada em Grupo, receberam cinco sessões de instrução junto com alguns tipos de expectativas e fez dois tipos de teste de leitura e autoimagem como pré e pós-teste. Em geral, os resultados não mostraram diferença significativa entre os escores médios dos dois grupos no pós-teste de autoimagem. Os resultados revelaram que o grupo de expectativas individuais superou significativamente o grupo de expectativas baseadas em grupo no pós-teste de compreensão de leitura. Os resultados sugerem que o uso de diferentes formas de expectativas nas aulas de línguas pode ser fundamental para melhorar a autoimagem dos alunos e a compreensão de leitura.El estudio examinó el efecto de las expectativas individuales y grupales sobre la autoimagen y la comprensión lectora de los estudiantes de inglés como lengua extranjera. Este estudio exploró la efectividad de las expectativas individuales y las expectativas grupales para mejorar la autoimagen y la comprensión lectora entre los estudiantes de inglés como lengua extranjera. Para ello, se eligieron 50 de 120 estudiantes iraníes de inglés como lengua extranjera como muestra del estudio y se dividieron en dos grupos de instrucción de expectativas basada en el individuo e instrucción de expectativas en grupo, recibieron cinco sesionesde instrucción junto con algunos tipos de expectativas. y tomó dos tipos de pruebas de lectura y de autoimagen como prueba previa y posterior. En general, los resultados no mostraron diferencias significativas entre las puntuaciones medias de los dos grupos en la prueba posterior de autoimagen. Los resultados revelaron que el grupo de expectativas individuales superó significativamente al grupo de expectativas basadas en el grupo en la prueba posterior de comprensión lectora. Los hallazgos sugieren que el uso de diferentes formas de expectativas en las clases de idiomas puede ser fundamental para mejorar la autoimagen y la comprensión lectora de los estudiantes

Appropriate blood component therapy can reduce postcardiac surgery acute kidney injury through packed cell transfusion reduction

Background: Acute kidney injury (AKI) can happen due to different factors such as anemia. Packed cell (PC) transfusion is an important cause of AKI occurrence. The aim of the study is to investigate whether appropriate blood component (BC) therapy can reduce blood transfusion and it would result in AKI decreasing. Materials and Methods: We conducted a cohort study of 1388 patients who underwent cardiac surgery in one university hospital. A serum creatinine higher than 2 mg/dl, renal disease history, renal replacement therapy (chronic dialysis) were our exclusion criteria. Results: from our 1088 samples, 701 (64.43%) patients had normal kidney function, 277 (25.45%) were in the AKI-1 group, 84 (7.72%) had an AKI-2 function, and the rest of patients were classified as end stage. A mean of more than three PC units were transfused for the second and third stage of AKI, which was significantly higher than other AKI groups (P = 0.009); this higher demand of blood product was also true about the fresh frozen plasma, platelet, and fibrinogen. However, there were no needs of fibrinogen in the patients with normal kidney function. The cardiopulmonary bypass time had an average of 142 ± 24.12, which obviously was higher than other groups (P = 0.032). Total mortality rate was 14 out of 1088 (1.28%), and expiration among the AKI stages 2 and 3 was meaningfully (P = 0.001) more than the other groups. Conclusion: A more occurrence of AKI reported for the patients who have taken more units of blood. However, BC indicated to be safer for compensating blood loss because of low AKI occurrence among our patients

Evaluation of Antioxidant Effects of Water and Ethanolic Extracts of Iranian Pomegranate Seed on Lipid Quality of Trout Fillet and Determining the Level of Perishability at 2-4 ° C

Background and Aims Because of unsaturated fatty acid content, trout and fish products are highly perishable. For this reason, preservatives are used to prevent or delay spoiling during storage. The aim of this study was determination of antioxidant activities of pomegranate seeds extracts on lipid quality of trout fillet stored at 2-4&deg;C. Materials and Methods Prepared fish fillets were divided into two groups. One group was trout fillet without extract (control) and one in pomegranate seeds extracts that were stored in refrigerator for 6 days. Chemical tests such as Peroxide Value (PV), Thiobarbituric Acid Reactive Substances (TBARS), Total Volatile Basic Nitrogen (TVB-N) and Free Fatty Acids (FFA) were used to determine perishability of trout fillet. Results The PV, TBA, TVB-N and FFA were significantly (P < 0.05) lowest in the samples treated with ethanolic extracts of pomegranate seeds as compared to control group. (PV = 2.62 meq o2/kg, TBA = 1.26 mg MDA/kg, TVB-N = 22.13 mg/100g and FFA = 1.2 percent Oleic acid). Conclusion The result of this study demonstrated that pomegranate seeds extracts were efficiency to prevent lipid oxidation in trout fillet stored at refrigerator temperature. * Corresponding Author: Tehran University of Medical Sciences, School of Public Health. Email: [email protected]

Antibiotic resistance-susceptibility profiles of Lactobacillus strains from Lighvan, a traditional Iranian raw milk cheese

The minimum inhibitory concentration (MIC) of 16 antibiotics for 36 strains of Lactobacillus brevis, L. paracasei, L. paraplantarum and L. plantarum was determined by microdilution. Strains suspected to be resistant to particular antibiotics were further assayed by the Etest method. Taking as a cut-off presently defined breakpoints, atypical MICs compatible with acquired resistance were recorded by for tetracycline (in 2 strains), clindamycin (in 1 strain), chloramphenicol (in 3 strains) and trimethoprim (in 2 strains). However, MICs of these antibiotics were only slightly higher than the breakpoints, suggesting the absence of dedicated resistance mechanisms. In addition, resistance genes encoding ribosome protection proteins were not identified by PCR among strains displaying the highest MICs of tetracycline. In contrast, genes of this class were detected when total microbial DNA from the cheeses was used as the template. Resistant and doubtful strains should be excluded when selecting candidates for making new adjunct cultures.This research was founded by projects from the Vice Chancellor for Research, University of Tehran, lran (Grant no. 61 22-TNS2007), and the Spanish Ministry of Science and lnnovation (Reference, AGL2007-61869-ALI).Peer Reviewe