مجله علوم و فنون دریایی
سال نوزدهم شماره 2 (تابستان 1399)

In this study, genetic diversity of Pinctada persica population was evaluated using PCR-RFLP method. To determine and compare genetic diversity of P. persica populations in khark, shidvar, hendurabi and larak islands, 51 samples were collected from 1-6 m depths. DNA of samples was extracted by CTAB method. A pair of primers of Pinctada persica was used for polymerase chain reaction. Enzymatic digestion of PCR yield was performed using, AvaΙΙ, DdeΙ, HindIII, SfaNΙ and TaqΙ restriction enzymes. DNAs were collected and stained with silver staining after subjected to poly acrylamide gel electrophoresis The results revealed that electrophoresis and enzymatic digestion fragments of the 51 samples collected from four stations in the northern coast of Persian Gulf with all 5 enzymes were the same The results of this study confirm that Pinctada persica Based on the studied gene is completely homogenous in these stations and show no genetic diversity.

Nowadays demand for renewable and reliable energy sources due to the global warming, environment pollution and global energy crisis is of utmost importance in offshore engineering. As a result of recent developments in wind industries extracting energy from offshore wind resources has a growth. A number of researches are carried out in the field of land based wind turbines but investigations about floating wind turbines as a consequent of their dynamic behavior complexity are still limited and further more detailed surveys are required. This paper presents an open source and public simulation code for the analysis and design of floating offshore wind turbines. The dynamic behavior due to environmental and inertial loads is obtained using a fully coupled comprehensive numerical tool implemented in MATLAB. blade element momentum theory used to determination of aerodynamic loads on wind turbine as well as Panel method and Morison's equation to calculate the hydrodynamic loads considering the instantaneous position of wind turbine system. The results show the domination of aerodynamic loads on wind turbine dynamic behavior as well as stability of structure due to the great difference between values of dominate aerodynamic excitation frequency and system natural frequencies.

Maneuverability is an important quality of marine vehicles. Hydrodynamic coefficients of ship and rudder should be derived to simulate maneuvering tests. These coefficients can be obtained by using captive model test and empirical formula. Accuracy of rudder hydrodynamic coefficients is important to calculate rudder force as the most influence force in ship maneuver, precisely. Empirical formula usually are correspond to single rudder ships and for twin rudder ships numerical or experimental method are used. In this paper, by using numerical method and simulation of static towing test in computational fluid hydrodynamic environment for different angles, linear and nonlinear rudder hydrodynamic coefficients are calculated. Also, fluid velocity field around rudder is obtained to investigate separation for high rudder angle. The comparison of simulated results with the available experimental shows a very good agreement among them.

For study of changes in energy metabolism of brain in rainbow trout during early life stages, some samples were collected from fish larvae and fingerlings with initial weight 1.35±0.15 during 7 months. Sample collection was randomly made in 12 stages (7 samples per every 8 days, 3 samples per every 2 weeks and 2 samples every one month). Brain tissue was dissected and transferred to nitrogen tank before analysis. The brain tissues were homogenized and the supernatant was adjusted to measurement of glycogen, glucose, lactate, lactate dehydrogenase, pyruvate kinase and glucose-6- phosphatase. Results revealed statistically changes in the metabolites during the sampling, so, glycogen and lactate concentration showed an increasing trend by increasing in fish age, but glucose concentration did not follow this trend. The minimum glucose concentration in brain tissue was observed in seventh stage of sampling. Concentration of metabolism enzymes was showed fluctuations and increasing trend during sampling. Finally, it is proposed that environmental and nutritional factors and different requirement of fish to energy in different stages of life may be effective on metabolites concentrations and metabolism enzymes activity.

The effects of using the biorock method on the growth and survival of coral (Pocillopora damicornis( in the Chabahar Bay were evaluated. Coral pieces were placed on steel structures under a 6V electric field in the biorock process. The coral growth, growth performance and survival rates of corals during the twenty-eight weeks were studied. The mean coral growth in the biorock structure was 10.66 ± 0.3cm and the mean coral growth was 5.27 ± 0.2 cm in the non biorock structure. The results show a significant difference between coral growth in the biorock with non biorock structures (p <0.05). The results of this survey on the growth rate of Coral (P.damicornis( in the biorock structure compared to the control structures showed a two-fold increase in growth and a higher survival rate. The results of this study indicated that stimulation of coral growth by biorock method as well as the rapid responses of this species to the electrical field during the biorock process which could be used to stimulate coral growth survival for the protection and rehabitation program.

The importance of scale issues in geomorphic studies is the definition of wide variables in the analysis of levels with different scales that are projected according to goals and abilities. Considering that in sedimentary cell systems, there are processes that operate on a wide range of scales, it is important to determine the appropriate scale for studying these processes and their forms. In this study the coasts of Hormozgan province due to the diversity of landforms and coastal processes in its western and eastern parts was investigated. This coastal is divided into 6 cells and 17 sub cells based on geomorphologic unit and wave and currents pattern. 1: 25000 topographic map, 1: 100000 geology map, LandSat 5 satellite images, hydrodynamic data, wind, hydrology and large port dredging and sedimentology data were used for this purpose. This data was analyzed in ArcGIS 10.2 and coastal environment were classified based on common features of the form and process. Also an appropriate scale was determined for studying littoral cells based on our aim. The results indicated that all of these scales should be considered to determine management strategies. Studies have shown that scales used for coastal study include system scale (large scale), subsystem scale (moderate scale) and landform scale (small scale). temporal and spatial scales in the form of a littoral cell are in a moderate scale. It can be concluded the medium scales are usually of greatest interest for coastal management.