JOURNAL OF MARINE SCIENCES AND TECHNOLOGY
Year:2018 | Volume:17 | Issue:2|Papers Count:8

The interest in bi-stable structures comes from their ability that these structures can have two different stable equilibrium configurations to define a discrete set of stable shapes. The geometrical changes occur with no need to continuously consume power, and mechanical hinges to preserve the structure in each stable shape. It is known that asymmetric composite laminates can have bi-stable response to different kind of loadings. In this research, the non-linear temperature-curvature relationship for the asymmetric composite laminates is studied using Rayleigh– Ritz technique. Attention is focused on studying the effect of material temperature dependency and resin layers; especially in the bifurcation point by use of analytical method. To this end, the well-known analytical theories are extended and used to consider the temperature dependency of material. The results obtained from the theory are then compared with the finite element simulations results and a good correlation is obtained. Finally, an experimental investigation is carried out and several specimens with [90/0]T, [70/– 20]T and [70/20]T compositions were manufactured. In order to study the effect of resin layers, optical microscopy is utilized and the exact thickness of different layers in the manufactured specimens is determined. The thermal responses of the manufactured plates were measured and used to validate the results obtained from the analytical theory and finite element simulations.

Accurate estimation of sediment concentrations in hydraulic sediment transport from different viewpoint such as sediment discharge estimation of river, selection of hydraulic structures and etc. are important. With respect to importance of this issue in this study for prediction of sediment concentration of Karun river multi-layer perceptron artificial neural network (ANN / MLP) was used. For this purpose 125 field data including bottom concentration, flow velocity, nearest distance from the beach, and the total depth of flow and flow depth was used. Three statistical metrics namely mean absolute error (MAE), root mean square error (RMSE) and coefficient of determination (R2) were used to evaluate the performance of ANN model. The result shows that MLP model with one hidden layer, Sigmoid transfer function and 5 neurons have best structure in the modeling of sediment concentration of Kroon River. The R2 and RMSE value is equal to 0. 953 and 63. 37 mg/l in training stage and 0. 752 and 203. 02 mg/l in testing stage, respectively. Finally, the sensitive analysis also showed that the nearest distance from the beach and flow depth had the most and the least effect on the sediment concentration, respectively.

In this study, the molecular characteristics of Chiromantes boulengeri were investigated from intertidal waters of Arvand River, Minoo Island in 2014. For this reason, samples from intertidal zones of two areas across Minoo Island were collected and preserved in 70% ethanol, followed by transferring to the laboratory for further examinations. Genomic DNA was extracted using phenol-chloroform method and mitochondrial gene 16SrRNA was sequenced and compared with other species from GenBank NCBI. The morphological examinations using identification keys and phylogeny sequence results showed that all specimens belonged to Chiromantes boulengeri in the study area. Phylogenetic analysis revealed that there are mutation within C. boulengeri from two areas of Arvand River. It seems that, this species most probably is adapted to the different ecological conditions in this area.

The aim of this study was to evaluate the single and combined effects of dietary probiotic with prebiotic on growth performance, non-specific immune response, body composition, digestive enzymes activity and intestine bacterial flora of sobaity fingerling (Sparidentex hasta). For this purpose, 425 individuals of sobaity fingerlings were prepared with an average weight of 7. 64 ± 0. 3 g from the Mariculture Research Station of South Iranian Aquaculture Research Center. This study was carried out in a completely randomized design with four treatments and three replications (45 fish per each replication) in fiberglass tanks with 300 liters volume. Fish were fed with feed containing 0 (control group), 106 CFU probiotic per gram feed (treatment 1), 0. 5 and 1 percent prebiotic plus106 CFU probiotic per gram feed (treatment 2 and 3) at 4. 5 percent of body weight for a period of 42 days. At the end of the experiment, body composition, intestine, blood, plasma and mucus samples were collected. The obtained results indicated that dietary prebiotic and probiotic did not change growth performance, intestine bacterial flora and non-specific immune response of sobaity (P > 0. 05). Nonetheless, plasma bactericidal activity of control group was significantly higher that treatment 3 (P < 0. 05). Moisture and protein content of treatment 2 showed significant different compared to the control group (P < 0. 05). The results of this study showed that digestive enzymes activity including alkaline protease, amylse and lipase affected by administration of dietary prebiotic and probiotic (P < 0. 05). Overall, this study showed that single supplementation of probiotic and combination with prebiotic at the used amounts had no positive effects on growth performance and intestine bacterial flora and immune response (except plasma bactericidal activity) of sobaity but improve digestive enzymes activity.

Seaweed is favored seafood in some regions and is also used as feedstock for extracting fine chemicals. The total global seaweed production continues to grow This study investigated the biological activities of n-Hexane, Ethylacetate and Methanol extract of two red marine macro algae (Gracilariopsis persica and Hypnea flagelliformis), collected from the coast of Bandar Abbas, Persian Gulf, Iran. For identification the superior species with biological properties, the tested activities included Carotenoids content, total Phenolic content, total flavonoids content, antioxidant activity at the concentration (3 mg/ml) by ferric reducing power (FRP) and total antioxidant capacity (TAC) assay and at final, antibacterial activity was evaluated. This study revealed that the more effective macro algae extracts by maximum antioxidant capacity: FRP and TAC, were recorded for Ethylacetate extracts. The result showed the highest content of phenolic and flavonoid compounds were recorded for the Methanol extracts of Gp. persica, 45. 12± 0. 01 (mg GA/gr DW. ) and 2. 28± 0. 007 (mg QE /gr DW. ), respectively while H. flagelliformis showed the maximum Carotenoid content 17± 0. 06 (mg 100g-1). In addition, the highest antibacterial activity was recorded for the n-hexane and followed by Ethylacetate extracts. In general comparison, though, according to the results, antioxidant and antibacterial activity of species in this study were calculated less than standard, but could be accounted these seaweeds as safe biological properties and with abundance of them in coastal of Bandar Abbas, could be considered for future applications in medicine and dietary supplements.

Pesticides are environmental contaminants which normally enter to aquatic ecosystems after being used in aquaculture. In this research, acute toxicity of diazinon was studied on Caspian Sea common bream (Abramis brama). This pesticide may enter in aquatic food chain and cause serious problems for aquatic organisms as well as human. The acute toxicity test was performed during 96h in static renewal system based on the standard method proposed by OECD. A range finding test was carried out in aquariums containing 10L of test solution to determine the lethal range of diazinon on fish. The acute toxicity test was then preformed in 5 treatments and 3 triplicates for each treatment. Obtained data were analyzed using probit analysis with %5 confidence limit. According to the results, LC50 24h, LC50 48h, LC50 72h and LC50 96h of diazinon on Caspian Sea common bream was 10. 974, 10. 391, 9. 134 and 7. 316 respectively. The maximum acceptable toxicant concentration (MATC) of diazinon on Caspian Sea common bream was 0. 073 mg/l and the lowest observed effect concentration which is equal to LC50 96h was 2. 63 mg/l. According to the results and comparing with other studies, it can be discussed that Caspian Sea common bream is more resistant against diazinon rather than other fish species. In addition, lethal toxicity of diazinon takes place in a moderate range of toxicant concentrations.

In general, the analysis of the changes in the area of mangroves and its relationship with changes in the surface water flow into the coastal environment can provide valuable information on the adverse effects of climate change on these ecosystems and therefore play an important role in the efficiency and success of conservation and development programs of these ecosystems. Therefore, in this study, the relationship between changes in surface water flows into the coastal environment (occurrence of hydrological drought) and changes in the areas of mangroves in Khamir, Tiab and Jask habitats were investigated in a 30-year period (1986-2016). The results of this study showed that with the occurrence of severe and extreme hydrological droughts in the period after 1998 in the southern coasts of Iran, areas of Khamir, Tiab and Jask habitats also reduced in this period compared to the wet period before 1998. High correlation between hydrological drought occurrence and changes in mangroves areas in different habitats also indicate the adverse effect of reducing the fresh water entering the coastal environment on the areas of mangroves. The results of studies on mangroves in other parts of the world have also shown that reducing rainfall and fresh water inputs to the coastal areas reduce the areas or decrease the progression rates of mangroves. The results of this study by providing accurate information on mangroves responses to consequences of climate change can play an important role in the efficiency and success of adaptation programs to climate change and the conservation and development of mangrove forests in Iran.

In this paper, the venom apparatus of the marine cone snail C. frigidus that is peptide toxins manufacture section with pharmacological effect have been studied. The venom apparatus of about 6 specimens were removed and divided to 3 parts: The venom bulb, the proximal portions of the venom apparatus (close to venom bulb), the distal portions of the venom apparatus (close to pharynx). Then were fixed in Bouin's for 48 hours and transferred to 70% ethanol. After dehydration and Paraffin embedded, they were cut by microtome, collected on glass slides, stained with Haematoxylin-Eosin and studied by light microscope. The results showed that the venom bulb has longitudinal, transversal muscles, and a row of cubic cells with round nuclei. The proximal and the distal parts are composed of elongated cylindrical cells with the basal ganglia. The epithelial cells of the venom apparatus have abundant granules and in the distal part that are larger than the proximal. The passageway between the lumen of the venom duct and the pharynx is a channel that lead to the radula bag containing radula with different degrees of a formation. So, C. frigidus venom production and delivery was performed by synthesis in the venom apparatus, storage toxin in the radula teeth and the venom injection is done by the venom bulb and the best section for toxin peptide extraction is the distal portion of the venom apparatus. The reason is that this part, is active in the secretion of mature toxins that can use for Medicinal purposes.