علوم انسانی دریا
Mohammad Pakdel; hamed mohagheghnia; Bahram D Yousefi; lena abdolkhani
Abstract
From the beginning of the formation of Islamic independence, various discourses have been formed to counter the threats as well as to secure the national interests. The Persian Gulf region has been one of the priorities of the Islamic Republic. The strategy that has been proposed to ensure the security ...
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From the beginning of the formation of Islamic independence, various discourses have been formed to counter the threats as well as to secure the national interests. The Persian Gulf region has been one of the priorities of the Islamic Republic. The strategy that has been proposed to ensure the security of the Persian Gulf region is to apply the theory of deterrence. The deterrent strategy balances the confrontation with the United States as well as the countries of the Persian Gulf region and ensures and maintains the security of the Persian Gulf. As the three countries, Saudi Arabia, the United Arab Emirates and Bahrain, are trying to prevent a security agreement between Iran and the Gulf countries, and their effort is to keep the United States open to the region in order to prevent Iranian influence. Therefore, it is necessary to use a deterrent strategy to deal with crisis-causing and destabilizing factors and to promote Iran's position. According to the research, it should be said that the impact of the strategic security environment of the Persian Gulf on the deterrence system of the Islamic Republic of Iran is that firstly our strategy leads us to a defensive strategy and secondly, our deterrence system leads to triangular and network deterrence. In this descriptive-analytical study, an attempt has been made to study the deterrent system of the Islamic Republic of Iran in the Persian Gulf.
علوم زیستی دریا
Mahbobeh Mohamadi; Gholam-Reza Sharifi-Sirchi; Morteza Yosefzadi
Abstract
The biofouling phenomenon causes great economic damage to artificial structures, so that by reducing the maneuverability of vessels and thus reducing their speed, it increases fuel consumption as well as increases maintenance costs. Today, many studies have been done to solve the problems of biofouling, ...
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The biofouling phenomenon causes great economic damage to artificial structures, so that by reducing the maneuverability of vessels and thus reducing their speed, it increases fuel consumption as well as increases maintenance costs. Today, many studies have been done to solve the problems of biofouling, the most important of which is to identify natural antifouling compounds. In this study, the anti-folling properties of henna (Lawsonia inermis) were investigated using n-hexane, ethyl acetate, methanol and aqueous. Treatments were performed in 3 replications. After 24 hours, under a light microscope, the number of algae was counted by a neobar slide. Data were analyzed using SAS software and data were compared by Duncan's multiple range test. Statistical analysis of henna extracts on Chlorella vulgaris showed that there was a statistically significant difference between the treatments at the probability level of 0.001. Examination of the results related to growth changes showed that with the application of treatments, the growth of this algae was significantly inhibited. Ethyl acetate extract with a concentration of 5 mg/ml, deoxygenate extract with a concentration of 20 mg/ml and methanolic extract with a concentration of 80 mg/ml and aqueous extract with a concentration of 160 mg/ml were the most inhibitory effect on the survival of Chlorella vulgaris.
مهندسی دریا
Somayyeh Saffar; Mohsen Solimani Babarsad; Mohammad Mahmoodian Shooshtari; Mohammad Hosein Poormohammadi; Roozbeh Riazi
Abstract
Side weirs are used to control water levels as well as water diversion for various uses in canals and rivers. Due to the complexity of flow conditions inside weirs, in this study, in order to simplify the calculations and increase its efficiency, this structure was investigated in convergent channel ...
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Side weirs are used to control water levels as well as water diversion for various uses in canals and rivers. Due to the complexity of flow conditions inside weirs, in this study, in order to simplify the calculations and increase its efficiency, this structure was investigated in convergent channel conditions. To investigate this issue, different geometric parameters of weir and hydraulic currents were investigated. Based on the geometric parameters of the side weir, experimental scenarios were considered. Based on the scenarios, 5 side weir lengths, 4 side weir heights, and 3 downstream channel widths were considered as side weirs that were tested at different discharges. Due to the fact that different geometric and hydraulic parameters were assumed to be variable in these experiments, the effect of each on the structure was analyzed and solutions for selecting the optimal dimensions in the channel were introduced. Based on the experimental results, it was found that for a fixed upstream water height with a 19% reduction in the width of the downstream channel, the ratio of the flow deflection to the lateral channel increases by 30%. It should be noted that the change in the flow section by converging the passage channel causes the longitudinal profile of the water surface to have a minimum height fluctuation along the entire length of the structure.
مهندسی دریا
Mohammad Taghi Serajian; Alireza Masjedi; Mohammad Heidarnejad; Hooshang Hasonizadeh
Abstract
In this study, experiments are carried out to determine the deviation flow into the intake in a 90º convergent bend, aiming to investigate the effect of flow characteristics on deviation flow with and without submerged vanes. The effective variables include Froude number, convergence, and submerged ...
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In this study, experiments are carried out to determine the deviation flow into the intake in a 90º convergent bend, aiming to investigate the effect of flow characteristics on deviation flow with and without submerged vanes. The effective variables include Froude number, convergence, and submerged vanes’ angle. For this research, a Rectangular channel with a 90º arc was used, which was studied using four different discharges, four different angles of submerged vanes and four degrees of convergence of the end of the channel. According to the results, the deviation flow to the intake increases by converging the laboratory flume. As the end of the flume is converged, the deviation flow is further increased. As the flume is converged (b/B) from 0 to 0.75, the deviation flow is increased from 64.9 to 81.4%, showing a 16.5% increase. Deviation flow is decreased by installing submerged vanes. A decrease in submerged vanes’ angle reduces the deviation flow. Compared to the model without a submerged vane, deviation flow is decreased by 14.9, 9.9, 6.8, and 2.3% by installing submerged vanes at angles of 25, 30, 45 and 60º, respectively. Deviation flow is also decreased by increasing the Froude number, such that it decreases by 5.3% with the increase of Froude number from 0.14 to 0.23.
علوم انسانی دریا
Hamid Khanipour; Parvaneh Gelard; Mehdi Bagheri
Abstract
The purpose of this study is to identify and rank the components of the model of succession management of organizational knowledge workers in the Ports and Maritime Organization of Iran. The present research is applied in terms of orientation and descriptive-survey in terms of purpose and has been done ...
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The purpose of this study is to identify and rank the components of the model of succession management of organizational knowledge workers in the Ports and Maritime Organization of Iran. The present research is applied in terms of orientation and descriptive-survey in terms of purpose and has been done in a quantitative method. Data collection tool is a questionnaire that was conducted with the cooperation of 306 organizational knowledge workers and staff. In the analysis of the collected data, the identification components are ranked using the factor analysis model and the use of Smart PLS software. According to the results, the model of succession management of organizational knowledge workers in the Ports and Maritime Organization has five dimensions and eleven components and the results showed that the components of in-service methods and individual factors had the highest and lowest priority in model design, respectively.
مهندسی دریا
Hesamoddin Ravanbakhsh
Abstract
Calculating the forces acting from the fluid to different structures is a field of interest to many researchers. Lift and drag forces are the most important parameters in the hydrofoil issues. Given that the Newtonian Fluid assumption is common in most studies in this field; in this paper, the forces ...
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Calculating the forces acting from the fluid to different structures is a field of interest to many researchers. Lift and drag forces are the most important parameters in the hydrofoil issues. Given that the Newtonian Fluid assumption is common in most studies in this field; in this paper, the forces imposed on a hydrofoil in a laminar non-Newtonian fluid flow have been investigated. The model is Power law for non-Newtonian fluid, and is simulated for three dilatants, Newtonian and pseudo plastic fluid at angles of attack of zero, 5, 10, 15, 20 and 25 degrees, and behavior indexes of 0.5, 1 and 1.5 is considered. Creating Mesh, Processing, and Post-Processing Computing This research is done by three free and open source softwares, G-Mesh, Open FOAM, and Para view. For validation, the lift and drag coefficients in the behavior index 1, that's mean Newtonian fluid, are consistent with similar results. As the angle increases, the dilatant fluid separation phenomenon occurs earlier; also Lowering lift coefficient for this concentrated fluid occurs at a larger angle of attack.
علوم زیستی دریا
Somayeh Zangeneh; Solmaz Kakeshian; Solmaz Shirali; Ahmad Savari; Hossein Najafzadeh Varzi; Abdolali Movahedinia; Mohammad Zakeri
Abstract
The present study has performed to investigate the effects of different levels of soy and garlic phytoestrogens on ovarian structure in Yellowfin seabream (Acanthopagrus latus). A total of 105 Yellowfin seabream were divided in seven groups including a control group that were received standard ...
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The present study has performed to investigate the effects of different levels of soy and garlic phytoestrogens on ovarian structure in Yellowfin seabream (Acanthopagrus latus). A total of 105 Yellowfin seabream were divided in seven groups including a control group that were received standard food without any extract and six treatment groups that were received different doses of soy (2/5, 5 and 7/5%) and garlic (0/5, 1 and 2%) hydroalcoholic extract. Fish were fed daily at a rate of 3% of body weight twice for 14 days. Sampling was done in days of 0, 7, 10 and 14. In every time, a section of mid portion of gonad was cut for histological examination. The results showed that different doses of soy and garlic phytoestrogens have various effects on growth and development of gonad in Yellowfin seabream as a protandrous hermaphrodite fish, so that increase in dose and time of consumption of food containing garlic hydroalchoholic extract cause increase in number of vitellogenesis follicles and finally growth and development of ovary, while consumption of food containing soy hydroalcoholic extract cause observing of testis and immature ovaries containing previtellogenesis follicle and prevents gonad development from testis to ovary in protandrous hermaphrodite fish.