Slug mechanism in horizontal duct and simulation based on one dimensional two fluid dynamics

Thesis--University of Tsukuba, D.Eng.(A), no. 756, 1990. 3. 2

Allium hirtifolium Boiss: Radical scavenging property and the lowering effects on blood fibrinogen and factor VII

Enhancement of blood fibrinogen or factor VII increases cardiovascular diseases. Allium hirtifolium Boiss (Mosir) has been shown to have cardioprotective effect. This study, therefore, aimed to evaluate the effects of Allium hirtifolium Boiss on factor VII and fibrinogen blood levels. Its radical scavenging property was also measured. Twenty four NewZealand male rabbits were randomly designated into 3 groups of 8 and were fed for 60 days with normal diet, hypercholestrol (1%) diet or hypercholestrol (1%) diet+Mosir. At the beginning and 60 days after the start of the study, the blood fibrinogen and factor 7 were measured and compared in different groups. The Mosir radical scavenging property was measured using the beta-carotene linoleate method. The blood fibrinogen and factor 7 were higher in hypercholesterolemic group (26.7 +/- 329.22 and 17.1 +/- 277.7mg/dl) compared to normal diet group (13.7 +/- 287.25 and 18.2 +/- 230.0 mg/dl, respectively) (P<0.05), at the end of the experiment. The amount of blood fibrinogen and factor 7 were decreased in hypercholesterol+Mosir group (23.9 +/- 180.00 and 53.3 +/- 237.0 mg/dl) compared to hypercholesterol diet group (P<0.05). radical scavenging activity of Mosir extract was 52.1 +/- 3.3%. Mosir may have beneficial effect on heart by decreasing blood fibrinogen and factor 7 as cardiovascular risk factors. These effects of Mosir should be considered carefully in patients with hemostatic disorders. Asgari. S, Rafieian-kopaei. M, Pourgheysari. B, Ansari-Samani. R, Deris F, Shahinfard. N, Hojjati. MR and Salimi. M. Allium hirtifolium Boiss: Radical scavenging property and the lowering effects on blood fibrinogen and factor VII. Life Sci J 2012;9(3):1793-1798] (ISSN:1097-8135). http://www.lifesciencesite.com. 25

A comprehensive study of effective parameters on the thermal performance of porous media micro combustor in thermo photovoltaic systems

Low thermal performance is one of the biggest challenges of using micro combustor in Thermo-photovoltaic (TPV) system. In this study, a novel micro-combustor with porous media was designed and installed to enhance energy and exergy performance. Furthermore, the effects of several effective parameters including different porous media materials, length, porosity coefficient, and inlet mass flow on energy efficiency, exergy, entropy generation, wall temperature and its uniformity were studied. A comprehensive CFD model for using porous media in the micro-combustor of TPV systems was proposed. Results showed utilizing porous media significantly improve the exergy efficiency and energy output of TPV system. Therefore, using a 6 mm long porous media increased the average wall temperature by 111 K compared to the case without porous media. Additionally, the uniformity coefficient of the wall temperature decreased by 80.05 %, from 4.58 % to 0.89 %. This reduction increased the temperature uniformity of the outer wall of the micro-combustor with porous media compared to the case without a media, increasing the system’s lifetime. Moreover, the 6 mm-long porous media enhanced radiation efficiency and exergy efficiency by 37 % and 79.7 %, respectively, compared to the conventional micro combustor. The total energy conversion efficiency from the fuel chemical energy to electric power increased from 8.9 % to 12.32 %.<br/

Direct Vision Internal Urethrotomy with Application of Holmium: YAG Laser

INTRODUCTION: Male urethral stricture is a complicated urologic disease that could be successfully treated using internal urethrotomy. Laser internal urethrotomy has been used in many cases with favorable outcome in many studies. Holmium: YAG laser with its incisional properties on tissue is one of the laser types applied for internal urethrotomy.METHODS: We present a 19 year-old male with history of aortic valve stenosis and metallic aortic valvoplasty on prescription of oral anti-coagulant therapy (Warfarin) who was a candidate for internal urethrotomy due to bulbar urethral stricture. Holmium laser core-through urethrotomy was performed for him.RESULTS: Internal urethrotomy was done using the ablative 50-watt Holmium: YAG laser 2140 nm (manufactured by the Atomic Energy Organization of Iran [AEOI]). No complication was observed intra- and post-operatively. After 6 months of followup no evidence of urethral stricture was observed.CONCLUSION: According to our study, Ho-YAG laser core through urethrotomy is a safe and effective procedure. It is a less invasive alternative to more complex urethroplasty procedures for patients with post-traumatic urethral stricture with high risk of urethral bleeding due to anti-coagulant therap

A comprehensive study of effective parameters on the thermal performance of porous media micro combustor in thermo photovoltaic systems

Low thermal performance is one of the biggest challenges of using micro combustor in Thermo-photovoltaic (TPV) system. In this study, a novel micro-combustor with porous media was designed and installed to enhance energy and exergy performance. Furthermore, the effects of several effective parameters including different porous media materials, length, porosity coefficient, and inlet mass flow on energy efficiency, exergy, entropy generation, wall temperature and its uniformity were studied. A comprehensive CFD model for using porous media in the micro-combustor of TPV systems was proposed. Results showed utilizing porous media significantly improve the exergy efficiency and energy output of TPV system. Therefore, using a 6 mm long porous media increased the average wall temperature by 111 K compared to the case without porous media. Additionally, the uniformity coefficient of the wall temperature decreased by 80.05 %, from 4.58 % to 0.89 %. This reduction increased the temperature uniformity of the outer wall of the micro-combustor with porous media compared to the case without a media, increasing the system’s lifetime. Moreover, the 6 mm-long porous media enhanced radiation efficiency and exergy efficiency by 37 % and 79.7 %, respectively, compared to the conventional micro combustor. The total energy conversion efficiency from the fuel chemical energy to electric power increased from 8.9 % to 12.32 %.<br/

Flexible Ureterorenoscopy Versus Extracorporeal Shock Wave Lithotripsy for the Treatment of Renal Pelvis Stones of 10–20 mm in Obese Patients

Introduction: To compare outcomes of retrograde intrarenal surgery (RIRS) with extracorporeal shock wave lithotripsy (ESWL) as treatment of choice.Methods: A total number of 46 patients with renal pelvic stones 10-20 mm and body mass index (BMI) &gt;30 randomized in two groups underwent RIRS and ESWL from 2011 to 2014 and followed for 3 months.Results: The patients mean ± SD age was 36.1 ± 13.1 years in ESWL and 33.2 ± 11.4 years in RIRS groups (P = .1) with comparable BMI in both groups (36.2 vs 38.1). In ESWL and RIRS groups, the operation time was 72.2 ± 21 vs 66.5 ± 19 minutes (P = .061), respectively. Stone free rate (SFR) at 3 months was 68% in ESWL group vs 90.4% in RIRS group (P = .019). The complication rate was 20% in ESWL group vs 14.2% in RIRS group (P = .211) but all of them were minor and managed conservatively.Conclusion: According to our study, RIRS procedure in comparison with ESWL is a safe and successful option of treatment for renal pelvis stone of 10-20 mm in obese people

Evaluation of the Effect of Rewarding Managers on the Capital Structure and Financial Performance of Companies Listed on Tehran Stock Exchange

Object and purpose of the study: The aim of this study was to evaluate the effect of rewarding managers on the capital structure and financial performance of the companies listed on Tehran Stock Exchange in the time period of 2005-2012. Methods: Data of 58 companies and research hypotheses were tested using panel data and ordinary least squares of regression model. Findings: Based on the results of the study, factors such as size of the company and the changes in cash and ratio of market value to book value of equity have significant negative impact on the capital structure of the company, the other conclusion is that there is a significant positive relationship between board bonus and financial performance and parameters such as the size of the company. Conclusion: Rewarding managers causes to increase their efforts and thus increment of productivity and improvement of company performance. Keywords: Rewarding managers, Capital structure, Financial performance, JEL Classification.

An experimental investigation on the effect of middle length and inclination angle of S-shaped channel on two-phase flow patterns

An experimental investigation is conducted to study the effect of middle length and inclination angle of an S-shaped channel on adiabatic two-phase flow patterns. To study this effect, three channel lengths of 0.25, 0.50, and 1.00. m, and four bends at the angles of 22.5°, 45°, 67.5° and 90° were used along the test section which is 35.83. m long. The channel cross section dimensions were 0.05. ×. 0.10. m and the test fluids were air and water. The observed flow patterns in 12 cases were studied. Each flow pattern was identified by visual observation and recorded with video camera for further analysis of the collected data points. The momentum transfer phenomenon between the phases for passing the upward middle section along the S-shaped channel was closely investigated. Five flow patterns of vortex plug, vortex slug, vortex wavy-annular, churn and mist packet annular were observed. The vortex type flow patterns were recorded with high speed video camera. The physical mechanisms and momentum transfer related to formation of these flow patterns were explained in detail. Flow pattern maps were obtained and then compared for different middle lengths and inclination angles to perform a parametric study on the S-shaped channel. Moreover, effect of upstream/downstream of the S-shaped channel on the maps and transition lines were discussed. It was revealed that upstream effects reflect the interactions and momentum transfer between the phases. Therefore, flow pattern types mainly depend on upstream behavior. On the other hand, the amount of backward flow resulting in the establishment of countercurrent flow and creation of vortexes along middle section is determined by downstream effects. Increasing the middle length or inclination angle causes the transition to vortex plug flow pattern to occur at higher liquid velocities. It also causes the area with churn flow pattern on the map to expand ending in smaller vortex slug flow pattern area. However, increasing middle length or decreasing inclination angle, ends in smaller area of mist packet annular area. It is also observed that for higher middle lengths, increasing the inclination angle shifts the transition lines more remarkably.A dimensionless analysis of obtained flow pattern maps is also carried out. It is shown that effect of geometry changes along S-shaped pipeline on two-phase flow pattern transitions is determined by either inclination angle or elevation difference between two horizontal lines. The explained flow mechanisms, obtained flow pattern maps and the transition lines can be used to predict the particular flow pattern that will be established for a given mass flux, inclined length and angle along pipelines