Analysis of the hydrodynamic torque effects on large size butterfly valves andcomparing results with AWWA C504 standard recommendations

Farid Vakili-Tahami,Mohammad Zehsaz,Mahdi Mohammadpour,Ali Vakili-Tahami 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.9

Butterfly valves are widely used in various industries such as water distribution, sewage, oil and gas plants. The hydrodynamic torque applied on the butterfly valve disk is one of the most important factors which should be considered in their design and application. Although several methods have been used to calculate the total torque on these valves, most of them are based on hydrostatic analysis and ignore the hydrodynamic effect which has a major role to determine the torque of the large-size valves. For finding the dynamic-valvetorque,some empirical formulas and methods have been proposed; for example in AWWA C504 standard, a relationship for calculating the dynamic torque has been given and its variation versus disk angle has been stated. However, the use of these empirical relationships is restricted due to the conditions defined in the standards. In this paper, the dynamic-valve-torque has been calculated for a large butterfly valve under different conditions and also at the different opening angles of the valve disk. For this purpose a computational fluid dynamics (CFD) method has been used. The results have been compared with those given in the AWWA C504 standard recommendations. Moreover, the effects of the disk shape and its deformation, surface roughness, upstream/downstream pressure variation and disk-offset value have been studied.

The Effects of Thyme and Cinnamon Essential Oils on Performance, Rumen Fermentation and Blood Metabolites in Holstein Calves Consuming High Concentrate Diet

Vakili, A.R.,Khorrami, Behzad,Mesgaran, M. Danesh,Parand, E. Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.7

Essential oils have been shown to favorably effect in vitro ruminal fermentation, but there are few in vivo studies that have examined animal responses. The objective of this study was to evaluate the effects of thyme (THY) and cinnamon (CIN) essential oils on feed intake, growth performance, ruminal fermentation and blood metabolites in feedlot calves fed high-concentrate diets. Twelve growing Holstein calves ($213{\pm}17kg$ initial BW) were used in a completely randomized design and received their respective dietary treatments for 45 d. Treatments were: 1-control (no additive), 2-THY (5 g/d/calf) and 3-CIN (5 g/d/calf). Calves were fed ad libitum diets consisting of 15% forage and 85% concentrate, and adapted to the finishing diet by gradually increasing the concentrate ratio with feeding a series of transition diets 5 wk before the experiment started. Supplementation of THY or CIN did not affect DMI and ADG, and feed efficiency was similar between treatment groups. There were no effects of additives on ruminal pH and rumen concentrations of ammonia nitrogen and total VFA; whereas molar proportion of acetate and ratio of acetate to propionate decreased, and the molar proportion of propionate increased with THY and CIN supplementation. Rumen molar concentration of butyrate was significantly increased by adding CIN compared to control; but no change was observed with THY compared with control group. No effects of THY, or CIN were observed on valerate, isobutyrate or isovalerate proportions. Plasma concentrations of glucose, cholesterol, triglyceride, urea-N, ${\beta}$-hydroxybutyrate, alanine aminotransferase and aspartate aminotransferase were not changed by feeding THY or CIN. Results from this study suggest that supplementing a feedlot finishing diet with THY or CIN essential oil might be useful as ruminal fermentation modifiers in beef production systems, but has minor impacts on blood metabolites.

Investigating the possibility of replacing IN 738LC gas turbine blades with IN 718

Farid Vakili-Tahami,Mohammad Reza Adibeig 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

The possibility of replacing IN 738LC gas turbine blades with IN 718 is investigated in terms of their creep behavior at different workingconditions. The latter superalloy is domestically produced and therefore there is a strong interest in using this alloy in manufacturinggas turbine blades. For this purpose, first the creep behavior and constitutive equation of IN 718 have been determined using experimentaldata. Test samples were machined from as-received bars and their physical and mechanical properties together with their creep behaviorwere examined. Constant load uni-axial creep tests were carried out at two constant temperatures of 660 and 675°C. Initial stressesrange from 490 to 690 MPa that are below the yield stress at each temperature level. The test results verify the quality of the domesticallyproduced superalloy and show that its characteristics match with the international standards. In addition, numerical optimization techniqueswere used to obtain creep constitutive parameters of the produced alloy based on the experimental data. Then, the creep behaviorof gas turbine blades, which operate at different rotating speeds, was investigated using finite element method. The results show thatsince the creep deformation of IN 718 is high, it can only be used in low and medium power gas turbines.

Potentiality of Palm Oil Biomass with Cow Dung for Compost Production

Mohammadtaghi Vakili,Haider M. Zwain,Mohd Rafatullah,Zahra Gholami,Reza Mohammadpour 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.7

Recently, researchers are focused on the use of biomasses generated in oil palm industry as compost to overcome their negative impacts and recycle them to produce a useful byproduct for agriculture. This study investigated formation of compost from Palm Oil Biomass (POB) by adding Cow Dung (CD). The experiment was carried out under shade in plastic bins at different POB and CD ratios (4:0, 3:1, 1:1 and 1:3) to activate decomposition mechanism up to 11 weeks. Decomposing materials was frequently moistened and turned accordingly. The addition of CD has facilitated the composting process and treatment with 1:3 ratio of POB and CD had better quality than other treatments such that the C/N ratio, the Electrical Conductivity (EC) and pH for mature compost were 22.2, 2.83 mS.m−1 and 7.81 respectively.

Signature Transition in the Canonical Quantum Cosmology Based on Einstein-Dirac Theory

Babak Vakili 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.4

We study the classical and the quantum evolutions of a universe in which the matter source is a massive Dirac spinor field and the universe is described by a spatially flat Robertson-Walker metric. We focus on the those classical solutions that for which the scale factor has a smooth behavior in the transition from a Euclidean to a Lorentzian domain and show that this transition happens when the cosmological constant, , is negative. The resulting quantum cosmology is also studied, and closed form expressions for the wave function of the universe are presented. We show that there is a close relationship between the quantum states and the signature-changing classical solutions, suggesting a mechanism for creation of a Lorentzian universe from a Euclidean region without any tunneling.

Moving load induced dynamic response of functionally graded-carbon nanotubes-reinforced pipes conveying fluid subjected to thermal load

F. Vakili Tahami,H. Biglari,M. Raminnea 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.64 No.4

Dynamic response of functionally graded Carbon nanotubes (FG-CNT) reinforced pipes conveying viscous fluid under accelerated moving load is presented. The mixture rule is used for obtaining the material properties of nano-composite pipe. The radial force induced by viscous fluid is calculated by Navier–Stokes equation. The material properties of pipe are considered temperature-dependent. The structure is simulated by Reddy higher-order shear deformation shell theory and the corresponding motion equations are derived by Hamilton’s principal. Differential quadrature (DQ) method and the Integral Quadrature (IQ) are applied for analogizing the motion equations and then the Newmark time integration scheme is used for obtaining the dynamic response of structure. The effects of different parameters such as boundary conditions, geometrical parameters, velocity and acceleration of moving load, CNT volume percent and distribution type are shown on the dynamic response of pipe. Results indicate that increasing CNTs leads to decrease in transient deflection of structure. In accelerated motion of the moving load, the maximum displacement is occurred later with respect to decelerated motion of moving load.

Modelling the Impact of the Position of Frame Loss on Transmitted Video Quality

Ahmad Vakili,Jean-Charles Grégoire 한국정보기술융합학회 2011 JoC Vol.2 No.2

Histological evaluation of the effect of VEGF on auto-transplanted mouse ovaries

Maryam Zand-vakili,Hussein Eimani,Afsaneh Golkar-Narenji,Poopak Eftekhari-Yazdi,Abdolhosein Shahverdi,Paul Edward Mozdziak 한국통합생물학회 2016 Animal cells and systems Vol.20 No.5

One of the most important factors affecting survival rate of ovarian follicles during transplantation period is proper vascular development. The objective of the study was to evaluate the effect of vascular endothelial growth factor (VEGF) on auto-transplanted ovarian tissue. Twenty-one-dayold female mice (n = 30) transplanted as control group and 21-day-old female mice (n = 40) were divided into 4 groups that were treated with 0.5, 1, 2 and 4 μg/mL of VEGF directly injected to auto-transplanted ovarian tissue. Twenty-one days after transplantation, mice were treated with 7.5 IU pregnant mare serum gonadotropin and human chorionic gonadotropin. Transplanted ovaries were removed and sections were prepared from transplanted tissues for staining. The most effective dosage of VEGF on transplanted tissue was determined over H&E (hematoxylin and eosin) staining results. Slides were compared using TUNEL staining and CD31 assay for the most effective dosage. The percentages of preantral and antral follicles were not significantly different between transplanted group with 4 μg/mL VEGF and non-transplanted group. Lower apoptotic areas and higher CD31 expression were observed in transplanted ovaries treated with 4 μg/mL VEGF when compared to transplanted ovaries without VEGF treatment. VEGF positively affects the quality of ovarian tissue during transplantation. Survival rate of follicles and follicular development has improved with the effect of VEGF.

Improved performance of cerium conversion coatings on steel with zinc phosphate post-treatment

B. Ramezanzadeh,H. Vakili,R. Amini 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.30 No.-

The steel samples were pre-treated by cerium conversion layer. Then, zinc phosphate conversion coatingwas used as sealing agent for the cerium conversion layer to enhance its corrosion resistance. Thecorrosion performance and surface characteristics of the samples were characterized by electrochemicalimpedance spectroscopy, scanning electron microscope and X-ray photoelectron spectroscopy. Resultsrevealed that the post-treatment of the cerium conversion coating by phosphate coating significantlyincreased its corrosion resistance. A denser conversion layer with less cracks were precipitated on thesteel surface after post-treatment by zinc phosphate. The surface free energy was significantly increasedafter post-treatment by zinc phosphate.

The effect of adding ethanolic saffron petal extract and vitamin E on growth performance, blood metabolites and antioxidant status in Baluchi male lambs

Fereshteh Alipour,Ali Reza Vakili,Mohsen Danesh Mesgaran,Hadi Ebrahimi 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.11

Objective: This study investigated the effects of the administration of ethanolic saffron petal extract (SPE) and vitamin E (Vit E) on growth performance, blood metabolites and antioxidant status in Baluchi lambs. Methods: Thirty-two Baluchi male lambs (35.22±5.75 kg) were randomly divided into 4 groups. The 1st (control), 2nd (injectable saffron petal extract [ISPE]), and 3rd (Vit E) groups were respectively injected subcutaneously with either physiological saline (5 mL), SPE (25 mg/kg body weight [BW]) or DL-α-tocopheryl acetate (225 IU) once a week. An oral dose of SPE (500 mg/kg BW) was also administered to the 4th group (oral saffron petal extract [OSPE]). Feed intake and BW were measured for 42 days and blood samples were taken on days 1, 14, 28, and 42. The lambs were slaughtered, and tissue samples were taken. Results: Growth performance and many blood metabolites were not affected (p>0.05) by the treatments. Cholesterol of plasma in the ISPE and Vit E groups was similar and less (p< 0.01) than both the OSPE and control groups. Although there was no significant difference between the control and other groups for plasma triglyceride, the ISPE group showed lower (p<0.05) triglyceride than the OSPE and Vit E groups. The highest (p<0.01) plasma glutathione peroxidase (GPx) was detected in the OSPE group, while the ISPE and Vit E groups showed higher (p<0.01) superoxide dismutase (SOD) of plasma than the control. Malondialdehyde of plasma in the ISPE group was lower (p<0.05) than the OSPE. No differences (p>0.05) were observed among the groups for antioxidant status of both longissimus dorsi muscle and liver. However, the activity of GPx in the kidney and heart, as well as SOD activity in the kidney, were influenced (p≤0.01) by the treatments. Conclusion: Adding ethanolic SPE improved antioxidant status and lowered lipids oxidation in lambs. The SPE and Vit E demonstrated similar effects on antioxidant status in lambs.