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Although many desalination plants have been built in the countries around the Persian Gulf (PG) over the past decade, there exist crucial water demands in this region. Considering the limited water exchange between PG and the open seas, effluents more than the natural capacity of the PG will increase the sea-water salinity continuously. This excess salinity, in addition to threatening the marine ecosystems, endangers the water supply for many population centers. This study provides a comprehensive numerical analysis of the impact of existing and new desalination plants on the PG's salinity. In addition, the water residence time and pollutant extension have been investigated in the PG. There exist several concerns, especially in recent years about the probable threat of desalination growth in semi-enclosed seas such as PG. The effect of desalination plants on the mean salinity of PG is one the questions investigated in this research. Results demonstrate that the water residence times in the southern and northwestern regions are more than five years. This time is reduced to nearly 26 to 45 months in the eastern regions near the Strait of Hormuz. Generally, the desalination plants have a negligible effect on the salinity of PG in comparison with the climate conditions such as evaporation and water exchanges. Based on the results, a 50% increase in effluent discharge of existing desalination plants increases the average salinity of the PG by only 0.01 psu. However, the annual volume of net evaporation (that exits the clean water directly) is nearly 36 times more than the effluent discharge from the existing desalination plants. Furthermore, this value is almost 0.2% of the amount of water that enters the PG through the Strait of Hormuz. In spite of these findings, the regional effects can be significant in some parts of the PG. For example, the southern and western coasts of PG are generally more vulnerable to pollution than other areas. The main reason is the shallow water depth in these areas and the water recirculation pattern. Some sensitive local areas have been also addressed in this study. Among the studied regions, the coastlines at the northwest of PG and at the north the Qeshm Island are two susceptible areas. The findings of this study underscore the importance of considering a new integrated viewpoint in developing desalination plants within PG. [ABSTRACT FROM AUTHOR]

The objective of this investigation is to obtain a more profound understanding of the effective parameters of the velocity caps for bottom intake systems, utilizing particle image velocimetry (PIV) and OpenFOAM. Observations indicate a higher probability of surface vortex formation in square types compared to circular ones, with the vortex being formed downstream of the caps. Additionally, the flow pattern reveals that the flow whirls in a more favorable path into the circular caps as opposed to the square ones. Through both experimental and numerical comparisons of three shapes (rhombus, square, and circle), it becomes evident that the circular type outperforms the other types in terms of discharges through the intake, showing an improvement of about 8%. The results indicate that flow depth and height of the velocity caps are positively effective parameters for the flow rate, with respective influences of 90% and 30%. In contrast, the interaction between the flow and caps intensifies with an increase in the distance of the intake opening from the bed, which plays a negative influence on the flow rate. Enhancing the number of blades in caps proves to be the optimal approach for generating a smoother flow with minimal impact on the flow rate. Numerical simulations show a 50% reduction in cap height leads to a significant 33% decrease in flow rate. Additionally, rotating the square cap by 45° into a rhombus aligned with the flow direction results in a 7% discharge flow rate increase. [ABSTRACT FROM AUTHOR]

Smoothed-Particle Hydrodynamics (SPH) has drawn a great deal of attention in recent years to model various phenomena in engineering and science. SPH is a Lagrangian model in which moving particles represent the fluid body during simulation. Therefore, the initial distribution of particles may affect the model results along with the simulation, and a good initial condition can minimize numerical errors or increase the computational efficiency. Since SPH model particle distributions need a flow pattern, the dam break flow as a classic benchmark SPH problem is selected in this study, and the best initial particle distribution for this case has to be found. Different results, including the mean density of particles, hydrostatic and dynamic pressures and surge front position, are considered the main model results for the adequacy of different initial particle distributions to be discussed. All models are verified at first by simulating different test cases and comparing the results with analytical and experimental data. Acceptable agreements between these data show the model's capability in well predicting the dam break flows. Then, the effects of initial particle distribution on the results are investigated by considering five different particle distributions. For this purpose, Body-Centered Cubic (BCC), Simple Cubic (SC), Greedy, Voronoi Tessellation and Fibonacci algorithms for particle distributions have been modeled. To get reliable conclusions, these distributions have been utilized in models with different kernel functions as well as with different particle spacings. Based on the results, irregular arrangements such as Greedy distribution perform better than regular SC and BCC distributions in modeling dam-break flow. In addition, both Voronoi and Fibonacci distributions perform almost the same with a moderate level of accuracy. Regarding mentioned arrangements, the main outcome of this study, is that the initial particle distribution is an important issue in SPH models, which clearly affects the results. [ABSTRACT FROM AUTHOR]

Caisson breakwaters are mainly constructed in deep waters to protect an area against waves. These breakwaters are conventionally designed based on the concept of the safety factor. However, the wave loads and resistance of structures have epistemic or aleatory uncertainties. Furthermore, sliding failure is one of the most important failure modes of caisson breakwaters. In most previous studies, for assessment purposes, uncertainties, such as wave and wave period variation, were ignored. Therefore, in this study, Bayesian reliability analysis is implemented to assess the failure probability of the sliding of Tombak port breakwater in the Persian Gulf. The mean and standard deviations were taken as random variables to consider dismissed uncertainties. For this purpose, the first-order reliability method (FORM) and the first principal curvature correction in FORM are used to calculate the reliability index. The performances of these methods are verified by importance sampling through Monte Carlo simulation (MCS). In addition, the reliability index sensitivities of each random variable are calculated to evaluate the importance of different random variables while calculating the caisson sliding. The results show that the reliability index is most sensitive to the coefficients of friction, wave height, and caisson weight (or concrete density). The sensitivity of the failure probability of each of the random variables and their uncertainties are calculated by the derivative method. Finally, the Bayesian regression is implemented to predict the statistical properties of breakwater sliding with non-informative priors, which are compared to Goda's formulation, used in breakwater design standards. The analysis shows that the model posterior for the sliding of a caisson breakwater has a mean and standard deviation of 0.039 and 0.022, respectively. A normal quantile analysis and residual analysis are also performed to evaluate the correctness of the model responses. [ABSTRACT FROM AUTHOR]

In this paper, a sample from Tange-zagh iron mine was characterized by gravity and magnetic separation methods. The mineralogical studies showed that hematite and goethite are the main iron-bearing minerals with insignificant amounts of FeO. The results indicated that spiral separation yields higher separation efficiency than others. The combination of spiral and multi gravity methods showed that the grade and recovery could be obtained 58.7 and 55.6%, respectively. Scrubbing and de-sliming stages increased the recovery in the wet high intensity magnetic process. With a four-stage process of separation, the WHIMS by scrubbing and de-sliming was applied to achieve a final concentrate with grade of 62.6% Fe and recovery of 57.1% Fe. [ABSTRACT FROM AUTHOR]