Mineralogy,composition and heavy metals’ concentration,distribution and source identification of surface sediments from the saline Maharlou Lake (Fars Province,Iran)

This study concerns the mineralogy, spatial distribution and sources of nine heavy metals in surface sediments of the Maharlou saline lake, close to the Shiraz metropolis in southern Iran. The sources for these sediments were studied by comparing the mineralogy and the distribution of heavy metals, using multivariate statistical analysis (correlation analysis and principal component analysis). The geochemical indices, including geo-accumulation index (Igeo), contamination factor (CF) and pollution load index (PLI), were used to assess the degree of heavy metal contamination in surface sediments. Sediment quality guidelines (SQGs) have also been applied to assess its toxicity. The XRD analysis shows that the main minerals of the surface sediments are aragonite, calcite, halite and quartz, with small amounts of montmorillonite, dolomite and sepiolite. The total heavy metal contents in surface sediments decrease in order of Sr?>?Ni?>?Cr?>?Zn?>?Cu?>?Co?>?Pb?>?As >?Cd and the average concentrations of Sr, Ni and As exceeded more than 10, 5 and 3 times, respectively, by comparing with the normalized upper continental crust (UCC) values. The results of pollution indices (Igeo, CF and PLI) revealed that strontium (Sr), nickel (Ni) and arsenic (As) were significantly enriched in those sediments. Based on the sediment quality guidelines (SQGs), Ni would infrequently cause toxicity. Multivariate statistical analysis indicated that the Ni, Co and Cr came mainly from natural geological background sources, while Cd, Cu, Pb, and Zn were derived from urban effluents (especially traffic emissions) and As originated from agriculture activities. Significant relationships of Sr with S, CaO and MgO in sediments suggest that Sr was derived from carbonate- and gypsum-bearing catchment source host rocks.     

Earthquake early warning for Portugal: part 1 - Where does it matter?

Bulletin of Earthquake Engineering - In the last five centuries, Portugal was affected by several earthquakes of strong magnitude (M > 7) that caused widespread destruction and a...     

Water Curtain System Pre-design for Crude Oil Storage URCs: A Numerical Modeling and Genetic Programming Approach

In this paper the main criteria of the water curtain system for unlined rock caverns (URCs) is described. By the application of numerical modeling and genetic programming (GP), a method for water curtain system pre-design for Iranian crude oil storage URCs (common dimension worldwide) is presented. A comprehensive set of numerical simulations is performed using the finite element based commercial software (COMSOL 5.1) where the results are used as database for genetic programming. Describing equations of water inflow to the filled and empty caverns and water production rate of water curtain boreholes are generated using GP. By equating the proposed equations to each other, water curtain system can be pre-designed. Relative error of the generated GP equations shows their ability and accuracy. Applying a standard regression coefficient method, sensitivity analysis of parameters related to water curtain performance and water inflow to the caverns is performed as well. The results help the design of the water curtain system for crude oil storage caverns worldwide.     

Analytical study on accelerating falling of non-spherical particle in viscous fluid

Unsteady motion of a vertically falling non-spherical particle has attracted considerable attention due to its frequent applications in nature and industry.A series of semi-analytical methods have been used to raise the results＇ accuracy as well as widening the region of convergence.The current study pursued a new analytical solution for the unsteady motion of a rigid non-spherical particle in a quiescent Newtonian fluid,based on the Optimal Homotopy Analysis Method.With a view towards obtaining the highest level of accuracy and ensuring the convergence of the analytical results,the averaged residual errors were obtained and minimized.In addition to flexibility,it was also proven that the proposed method can lead to completely reliable and precisely accurate results.Based on the series solution,the effects of physical parameters on the terminal settling velocity（i.e.the greatest velocity that a falling body may reach）and the acceleration time（i.e.the time that a particle reaches the settling velocity） are investigated.     

Assessment of hydro power potential of Swat,Kohistan Himalayas: A solution for energy shortfall in region

Pakistan is facing acute power dearth these days due to which people are suffering from privation and their economic condition is deflating. Expensive imported fossil fuel for thermal power generation is pressing them hard and exacerbating the situation. The total power produced in the country by all means is less by 4000 MW than the requirement of Pakistan. So this is the prime time to think about exploring aboriginal and renewable power resources. This article converses about hydro power resources of Swat, North Pakistan, one of the most promising areas in hydro power production. The area drained by the Swat River and its tributary net work is a part of Kohistan Himalayas and has a potential of more than 1000 MW that can contribute 25% to the total energy shortfall in the country and the same is 150% more than the shortfall experienced in the province of Khyber Pakhtunkhwa that hosts Swat Valley. Due to great relief difference acquired within a small stretch, the perennial Swat River and its tributaries become pertinent for power production as high head projects and also gain importance in irrigation as well.     

A Genetic Algorithm for Stochastic Inversion in Contaminant Subsurface Hydrology

Identifying the spatial distribution of hydrological properties of aquifers is a key problem in subsurface hydrology. The aquifer structure plays an important role in contaminant transport. Identifying the properties (primarily the hydraulic conductivity) is essentially an inversion problem that is ill-posed, non-unique and computationally intensive by definition. In this work, the non-uniqueness of the inverse problem is tackled via a novel Genetic Algorithm approach combined with a geostatistical method (Sequential Indicator Simulations) for construction of realizations of properties spatial distributions, which are modeled as random. The Genetic Algorithm cross-over operator is based on a novel concept of pilot-planes: daughter realizations adopt pilot-planes from one of their parents. In addition, each aquifer realization is conditioned on the geological hard data and is constructed by sampling the facies distribution, evaluated by indicator variograms. The approach is illustrated in two test cases: a synthetic two-dimensional (2D) case and an actual three-dimensional (3D) case. The results have shown the ability of the proposed approach to generate a set of realizations, where each individual exhibits minor deviations from the measurements. Further, a comparison between the proposed approach and direct (Monte Carlo) approach shows that the Genetic Algorithm was able to generate an ensemble of solutions with a better fitting of the measurements than the direct approach by a significantly reduced computational effort.     

Towards realistic minimum-cost optimization of viscous fluid dampers for seismic retrofitting

This paper presents an effective approach for achieving minimum cost designs for seismic retrofitting using viscous fluid dampers. A new and realistic retrofitting cost function is formulated and minimized subject to constraints on inter-story drifts at the peripheries of frame structures. The components of the new cost function are related to both the topology and to the sizes of the dampers. This constitutes an important step forward towards a realistic definition of the optimal retrofitting problem. The optimization problem is first posed and solved as a mixed-integer problem. To improve the efficiency of the solution scheme, the problem is then re-formulated and solved by nonlinear programming using only continuous variables. Material interpolation techniques, that have been successfully applied in topology optimization and in multi-material optimization, play a key role in achieving practical final design solutions with a reasonable computational effort. Promising results attained for 3-D irregular frames are presented and compared with those achieved using genetic algorithms.     

On Earth’s Mantle Constitution and Structure from Joint Analysis of Geophysical and Laboratory-Based Data: An Example

Determining Earth’s structure is a fundamental goal of Earth science, and geophysical methods play a prominent role in investigating Earth’s interior. Geochemical, cosmochemical, and petrological analyses of terrestrial samples and meteoritic material provide equally important insights. Complementary information comes from high-pressure mineral physics and chemistry, i.e., use of sophisticated experimental techniques and numerical methods that are capable of attaining or simulating physical properties at very high pressures and temperatures, thereby allowing recovered samples from Earth’s crust and mantle to be analyzed in the laboratory or simulated computationally at the conditions that prevail in Earth’s mantle and core. This is particularly important given that the vast bulk of Earth’s interior is geochemically unsampled. This paper describes a quantitative approach that combines data and results from mineral physics, petrological analyses of mantle minerals, and geophysical inverse calculations, in order to map geophysical data directly for mantle composition (major element chemistry and water content) and thermal state. We illustrate the methodology by inverting a set of long-period electromagnetic response functions beneath six geomagnetic stations that cover a range of geological settings for major element chemistry, water content, and thermal state of the mantle. The results indicate that interior structure and constitution of the mantle can be well-retrieved given a specific set of measurements describing (1) the conductivity of mantle minerals, (2) the partitioning behavior of water between major upper mantle and transition-zone minerals, and (3) the ability of nominally anhydrous minerals to store water in their crystal structures. Specifically, upper mantle water contents determined here bracket the ranges obtained from analyses of natural samples, whereas transition-zone water concentration is an order-of-magnitude greater than that of the upper mantle and appears to vary laterally underneath the investigated locations.