INTERNATIONAL JOURNAL OF MARINE SCIENCE AND ENGINEERING
Year:2011 | Volume:1 | Issue:1|Papers Count:8

The traditional event tree analysis uses a single probability to represent each top event. However, it is unrealistic to evaluate the occurrence of each event by using a crisp value without considering the inherent uncertainty and imprecision a state has. The fuzzy set theory is universally applied to deal with this kind of phenomena. The main purpose of this study is to construct an easy method to evaluate human errors and integrate them into event tree analysis by using fuzzy concepts. A systematic fuzzy event tree analysis algorithm is developed to evaluate the risk of a largescale system. A practical example in of offshore oil pipeline is used to demonstrate this procedure.

Ocean waters often show layered structures especially where exchange flow between two basins occurs. These structures are often attributed to processes such as double-diffusive convection, internal waves, turbulent modulated mixing. In this paper by examining the vertical structures of temperature, salinity and density, of the middle parts of Caspian Sea it is shown that such layered structure may be due to the normal modes of the internal waves as double diffusive convection (the density ratio is often negative) does not often occur in these waters. Contours of isotherm, isohaline and isopycnal show the existence of rather regular wavy structures, which may indicate that internal waves, which are produced of exchange, flow between two basins, as a result of horizontal density gradients (usually from middle basin to southern basin) may generate these layers. The flow velocity associated with this gravity driven flow is about 0.1 to 0.15 m/s which gives a Froude number of about one. The wave lengths of these wavy structures are about 200 km and hence, the frequencies of them are of order of inertial frequency at these latitudes. The normal modes of these waves appear to have a near steady structure and can fold the inflow front from the Northern part of the Caspian Sea to the Southern deep basin. The thickness of formed layers is found be about 10-20 m which is in agreement with the values predicted by the model of Wong et al. (2001) and is less likely to be produced by double diffusive convection as the density ratio is often not appropriate for this process.

TiO2 photo catalyst was prepared in presence of nano SiO2 and Hydroxy Propyl Cellulose (HPC) by sol gel method with Titanium Tetra IsoproPoxide (TTIP) as titanium precursor. Additional effect of HPC in preparation of nano catalyst, and photo catalyst properties measured and characterized by FT-IR, FT-Raman and SEM. The catalyst size and structural properties of the film were determined by.-Ray Diffraction (.RD). The nano particles of TiO2/SiO2 with HPC contained anatase phase in advance. The surface area measured by the Brunauer, Emmett and Teller (BET) method. Presences of Ti and Si in the nano structure were confirmed by Scanning Electron Microscopy (SEM) equipped with Energy Dispersive.-ray (ED.) spectroscopy. Photo catalyst properties of TiO2/SiO2 examined at first for decomposition of Methyl Red as azo dye, and then for degradation of 5ppm diazinon solution as an organo phosphorous insecticide pollutant in marine source, (Caspian Sea water). Concentration of diazinon during of degradation by TiO2/SiO2 photo catalyst was monitored by UV-Vis spectrophotometery. The insecticide degradation occurred within 105 min of photocatalytic treatment.

Fault Tree Analysis (FTA) as a Probabilistic Risk Assessment (PRA) method is used to identify basic causes leading to an undesired event, to represent logical relation of these basic causes in leading to the event, and finally to calculate the probability of occurrence of this event. To conduct a quantitative FTA, one needs a fault tree along with failure data of the Basic Events (BEs). Sometimes it is difficult to have an exact estimation of the failure rates of individual components or the probabilities of occurrence of undesired events due to a lack of sufficient data. Furthermore, due to imprecision in failure data of BEs, the overall result may be questionable. To avoid such conditions, a fuzzy approach may be used with the FTA technique. This reduces the ambiguity and imprecision arising from the subjectivity of data. Traditional FTA method needs a sound data base of failure of all BEs for quantifying the probability failure of system, whilst there is not such a database available in offshore pipeline industry, therefore, fuzzy FTA approach is proposed to deal with this issue. The proposed model is able to quantify the fault tree of offshore pipeline system in the absence or existence of data. This paper also illustrates with a case study the use of importance measures in sensitivity analysis.

Coral reefs which form some of the most diverse ecosystems on Earth support many symbiotic relationships. Symbiodinium can provide up to 90% of a coral.s energy requirements. Temperature rise, turbid water and high salinity in the Persian Gulf were among the factors separating zooxanthellae from corals and result in bleaching phenomenon. Therefore, it is crucial to identify Symbiodinium of the Persian Gulf corals. Since zooxanthellae identification according to morphological characteristics is not precise enough, today, Symbiodinium different clades are identified using molecular techniques. In this study, Symbiodinium of genus Acropora as a dominant scleractinian coral in Farur Island, northern Persian Gulf were identified using molecular techniques. For this reason, sampling from depth of 7-10 meters was carried out. After DNA extraction, the target gene which was large subunit ribosomal RNA (28S rDNA) gene was amplified, using Polymerase Chain Reaction (PCR). Then the amplified fragments analyzed, by sequencing, and Symbiodinium clade was identified, using phylogenetic tree, and the situation of considered clade and its phylogenetic association with other studied samples in Iran and other parts of the world were defined. The results showed that clade D was the only symbiont of Acropora off Farur Island. Since clade D is the most resistant clade against environmental changes, it is natural to identify this clade from Symbiodinium in Persian Gulf specific conditions.

In this study, the amount of nickel and vanadium elements in the soft tissues of rock oysters (Saccostrea cuculata) and sea water from coastal areas of Qeshm Island, the biggest island of Persian Gulf located in the south of Iran, were measured to evaluate the contamination of the aquatic environment and organisms. Following the bioassay, weighing and chemical digestion of the samples, finally the amount of nickel and vanadium in the soft tissues of the oysters and sea water samples were measured via the ICP system. The results indicated that the average concentration of nickel and vanadium found in the sea water were respectively: 15.7 and 37.9 micro grams per liter and in the soft tissues of oyster: 2.44 and 1.91 mg per kg respectively. In comparison with the FDA and WHO standards, only the concentration of nickel in the soft tissues of oysters was in a permitted level, and the rest exceeded the permitted levels.The average concentration of metals in the north side of the island were more than that found in south of the island but this difference was not statistically significant (p>0.05).

In this paper, a feasibility study of building a Human Powered Hydrofoil (HPH) vessel is reported.Hydrofoil vessels are a well-known class of high-speed crafts. In addition to high-speed operation, the hydrofoils have a reliable maneuvering capability, good stability and proper operation in waves. Also, a human powered vehicle, nowadays is an advancing idea. Different aspects of the design and construction of a HPH is explained. Some ideas are principles and others are ideas, set forth and should be further analyzed and validated theoretically and experimentally.

Nuclear markers such as microsatellites have allowed the identification of conservation and management populations of the Hawksbill turtles. In present study, eight microsatellite loci were studied.60 samples of hawksbill turtles. flipper from Shidvar and Hormuz Islands have been surgically removed and preserved in 20% DMSO buffer.DNA was extracted using DNP KIT and amplified by PCR methods. The average number of alleles in Shidvar and Hormoz were 7 and 7.37 respectively with range of 7-13. The average expected and observed heterozygosity was 0.77 and 0.46 respectively. The linkage disequilibrium and deviations from Hardy-Weinberg equilibrium have been tested. The Fst values was 0.048, showing a significant difference between the two sites (P<0.01). The genetic distance between populations was found to be 0.27, which indicates that the genetic difference among the studied populations is pronounced. These results together with highly significant RST of genotypic differences between these pairs of samples support the existence of different genetic populations of Eretmochelys imbricata within the Iranian Islands of the Persian Gulf.