Journal of the Persian Gulf (Marine Science)
Volume:8 Issue: 27, Spring 2017

Sloshing describes liquids motion in the semi-filled tanks, and exerts dynamic loading on its walls. This effect is of great importance in a number of dynamic systems e.g. aerospace vehicles, road tankers, liquefied natural gas carriers, elevated water towers and petroleum cylindrical tanks. Pressures insert impacts which are important for structural strength evaluation and its correct assessment is challenging for designers because of high share of nonlinear effects, complicated changes of free surface, strong impact phenomenon and air trapping effects. Since, numerical capabilities of the Smoothed Particle Hydrodynamics (SPH) method allow proper simulation of the fluid and/or the free surface we used it to investigate the behavior of a water tank exposed to a harmonic excitation. Besides, a Finite Volume (FV) analysis was employed using FLOW3D software, for the further comparison of the results from the SPH method. To assess the results, temporal variations of the impact pressure at the specific height of the tank wall is compared against the results from the experiment and also, the Finite Difference (FD) method. The comparison showed strong correlation of SPH results with the experimental ones. But, FLOW3D is not sufficiently capable of estimating the trend of pressure time history especially near the extremes.

Keeping health and nutritional value of the packed foods has a great value in food industries. Among the diverse methods of food processing and packaging, vacuum packaging is one of the best methods for a variety of food products, such as fish. In order to evaluate the effectiveness of such method in preventing of bacterial growth during preservation of fish fillets, four vacuum packed fish of Scomberomorus commerson, Saurida tumbil, Otolithes ruber, and Oreochromis niloticus were investigated. Using microbial cultivation followed by speciesspecific culture media and staining showed negative growth of Enterococcus sp., but positive growth of Escherichia coli and Listeria sp. Results showed that the highest microbial contamination of four studied fillets was as follow: Otolithes ruber> Oreochromis niloticus> Scomberomorus commerson > Saurida tumbil. Results also showed that as a variety of microbial species contamination, the most contaminated fillet belong to Oreochromis niloticus. Results of the present study showed that vacuum packaging was un-successful against the growth of the Escherichia coli and Listeria sp., but fully successful against the Enterococcus sp. In conclusion, it seems that vacuum packaging needs to be paired with other hygienic methods for keeping bacterial growth out of the fish fillets.

In this study, microfunnel-supported liquid-phase microextraction method (MF-LPME) was optimized and applied for the determination of some chlorophenoxyacetic acids (CPAAs) from natural water samples. The extraction was performed with 540 μL toluene which was retained at the surface of the sample solution using an upside down microfunnel. After the extraction, toluene was moved into the narrow stem of the microfunnel by pushing the device inside the sample. Then, using a microsyringe, it was transferred into micro vial followed by evaporation using a gentle stream of nitrogen. The residual re-dissolved into 50 μL acetonitrile, diluted to 100 μL with deionized water and analyzed applying a high performance liquid chromatography equipped with a UV detector (HPLC-UV). Central composite design (CCD) was used for the optimization of factors influencing the extraction. Under the optimized conditions, the limits of detection were 0.42 and 0.43 ng mL-1 for 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylphenoxyacetic acid (MCPA), respectively. Preconcentration factors of 66 and 80 were obtained for 2,4-D and MCPA, respectively. The precision of the technique was evaluated in terms of repeatability which was less than 11.1% (n=5). The applicability of the proposed method was evaluated by the extraction and determination of CPAAs from some natural water samples.

Reverse phase dispersive liquid- liquid microextraction (RP- DLLME) coupled with spectrophotometry is introduced for the detection of total phenol in the muscle tissue of fishes, such as Sphyraena genie, Otolithes ruber, Rastrelliger kangurta, Lutjanus johnii and Barbus Subquin Cunciatus. Phenols in fish tissues were extracted by ultrasonic bath and derivatization with 4- aminoantipyrine. The factors influencing on the extraction efficiency, including type and volume of extracting solvent, extraction time, concentration of 4- aminoantipyrine, derivatization reaction temperature and centrifugation rate and time were evaluated. The used protocol was found to yield a linear calibration curve in the concentration range of 0.4 and 1.6 mg L-1 with a limit of detection of 0.012 mg L-1. The enrichment factors founded 83 -fold. The SPSS was utilized for statistical analysis. The technique has been successfully used for the analysis of total phenols in fish species from several locations in Chabahar Bay.

Marine terraces have long been used as baseline geodetic markers of relative past sea levels, reflecting the interaction between vertical crustal movements and sea level oscillations. The terraces age and elevation of shoreline angles can be used to determine uplift rate. Disparate uplift rates in pervious investigation in the study area are related to manual measurements based on the surface morphology without considering erosion and other natural factors were deformed the marine terraces morphology. The uplift rate strongly depends on the temporal and spatial accuracy of shoreline angle measurement. In this research, Chabahar Marine Terrace has been assessed by using geologic information, morphometric analysis, and radiocarbon dating along with using of digital elevation model and TerraceM program to estimate accurate uplift rate and to determined mechanism of uplift. High-resolution topographic data and TerraceM program significantly simplify the remote identification of shoreline angles, to rapidly assess and map them at regional and local scales and providing accurate estimation of past sea levels. Uplift rate was estimated by 15 topographic swath profile along a sequence using digital elevation map. Calibrated radiocarbon ages of 3 samples fall between 46944±3055 yr B.P. and 29304±557 yr B.P., revealing that strata uplifted about 29 ka years ago with a rate of between 2-5 mm/yr (average: 4 mm/yr). In general, uplift rates increase from west to east of the Chabahar Marine Terraces. However, some local increases or decreases in uplift rates were observed due to local tectonics. According to morphology of terraces, correlation of rock units, faults density and variations of thickness of litho-stratigraphic units, it is concluded that the coastal area of study can be divided into two separate zones I and II which can be separated by faults. The sequence of Chabahar Terrace coincides with the interstadial stage of Marine Isotope Stage 3 (MIS3). Chabahar wave-cut terrace has been built by uplift along with sea level rise at 29 ka years ago. Altogether, considering the stability of sea level changes in the region, factors such as tectonics, erosion and sedimentary basin have determined the current shape of Chabahar Terraces.

Green synthesized nanomaterials have garnered much attention due to their economic and ecofriendly benefits over common chemical methods of synthesis. In the present study, zinc oxide nanoparticles with an average diameter of 16.51 nm were successfully biosynthesized using the aqueous extract of the red seaweed Hypnea musciformis. The morphology, purity and quality of biosynthesized Hy-ZnONps were highly comparable with its commercial counterpart with less toxicity. The MIC and MBC values were evaluated and the potential ecotoxicity of Hy-ZnO NPs against Artemia salina was investigated in various concentrations (0, 1, 5, 10, 15, 25 μg/ml) and mortality rate in 24 hours was evaluated. The findings provide preliminary information for designing cost-effective, eco-friendly green synthesis methods for large-scale production of ZnONps using marine macroalge.