Analytical Modeling of Well Design in Riverbank Filtration Systems

Analytical studies for well design adjacent to river banks are the most significant practical task in cases involving the efficiency of riverbank filtration systems. In times when high pollution of river water is joined with increasing water demand, it is necessary to design pumping wells near the river that provide acceptable amounts of river water with minimum contaminant concentrations. This will guarantee the quality and safety of drinking water supplies. This article develops an analytical solution based on the Green's function approach to solve an inverse problem: based on the required level of contaminant concentration and planned pumping time period, the shortest distance to the riverbank that has the maximum percentage of river water is determined. This model is developed in a confined and homogenous aquifer that is partially penetrated by the stream due to the existence of clogging layers. Initially, the analytical results obtained at different pumping times, rates and with different values of initial concentration are checked numerically using the MODFLOW software. Generally, the distance results obtained from the proposed model are acceptable. Then, the model is validated by data related to two pumping wells located at the first riverbank filtration pilot project conducted in Malaysia.     

Monitoring hawksbill turtle nesting sites in some protected areas from the Persian Gulf

Iranian nesting populations of the critically endangered hawksbill turtle(Eretmochelys imbricate) are some of the most important in the Indian Ocean. In this study, four of the most important hawksbill nesting grounds in the Persian Gulf, situated within three Iranian marine protected areas, were surveyed during nesting season,including Nakhiloo, Ommolgorm and Kharko Islands and the mainland beaches of the Naiband Marine-Coastal National Park(NMCNP). We present GIS maps of these key nesting grounds and describe sand texture of key nesting zones, along with conservation recommendations. About 9.2(28.3%) out of 32.5 km of all shores surveyed in this study were used by nesting hawksbill turtles follows: Nakhiloo: 1.4 km(52% of potential nesting area);Ommolgorm: 1.94 km(40%); Kharko: 3.4 km(28%), and NMCNP: 2.46 km(18.9%). The average nesting density was calculated as 131 nests/km at Nakhiloo, 76 nests/km at Ommolgorm, 7 nests/km at Kharko, and 15 nests per km at NMCNP. Highest nesting density was observed in Nakhiloo and Ommolgorm. It is thought that high hawksbill nesting density in these islands seems likely a result of limiting adequate nesting shores rather than the size of population, and also low density in Kharko and NMCNP more related to past and current pressures and low population density. With the exception of Ommolgorm Island, sands at the nesting grounds were well sorted.Grain size indicated that female hawksbill turtles in the Iranian Persian Gulf nest in sands that are generally mixed, with mean grain size ranging from coarse sands(0.4Φ;～0.5–1 mm) to fine sands(2Φ;～0.25 mm). We provide and discuss conservation recommendations and suggestions for future.     

An LMI approach to H∞-control of time-delay systems for the benchmark problem

In this paper, three H_∞-control design methods are developed and applied to a three-storey building with an active mass damper as a control mechanism. The system of equations of the structural system, including the actuator and sensors, has been developed directly from experimentally derived data which forms the basis of the benchmark study discussed in this paper. The building plus the damper are modelled as a nominally linear system with input as well as state delays. Feedback control synthesis are first performed by using either of the two forms; the first is a pure state feedback and the other is a static output feedback. The analytical results are cast into a Linear Matrix Inequality (LMI) framework which can be solved numerically by efficient interior-point methods. The developed system is subjected to two historical earthquake excitation inputs (ElCentro and Hachinohe) and to the Kanai–Tajimi filter. The response is given in the form of indices in order to compare with other solutions of the benchmark problem. In addition, simulation results pertinent to the developed techniques are presented. © 1998 John Wiley & Sons, Ltd.     

Effect of glyphosate-based herbicide on early life stages of Java medaka (Oryzias javanicus): A potential tropical test fish

Glyphosate is globally a widely used herbicide, yet there is little information on their toxicity to marine fishes. Java medaka, a small tropical fish native to coastal areas in several Southeast Asian countries, is viewed as a suitable candidate for toxicity test and thus was used for this study. Java medaka adults were cultured in the laboratory and the fertilized eggs of the F₂ generation were exposed to different concentrations of glyphosate-based herbicide (100, 200, 300, 400 and 500 ppm) until they hatched. The survival and hatching rates of the embryos, changes in the heart rate and morphological impairments were recorded. Generally, survival and hatching percentage decreased as glyphosate concentration increased. Absence of pectoral fin(s) and cornea, permanently bent tail, irregular shaped abdomen, and cell disruption in the fin, head and abdomen are among the common teratogenic effects observed. Furthermore, risk factor also increased with the increased in glyphosate concentrations.     

Urmia lake water level fluctuation hydro informatics modeling using support vector machine and conjunction of wavelet and neural network

In this research, the simulation of Urmia Lake water level fluctuation by means of two models was applied. For this, Support Vector Machines (SVM), and Neural Wavelet Network (NWN) models that conjugated both the wavelet function and ANN, developed for simulating the Urmia Lake water level fluctuation. The yearly data of rainfall, temperature and discharge to the Urmia Lake and water level fluctuation were used. Urmia Lake is the biggest and the hyper saline lake in Iran. The outcome of the SVM based models are compared with the NWN. The results of SVM model performs better than NWN and offered a practical solution to the problem of water level fluctuation predictions. Analysis results showed that the optimal situation occurred with use of precipitation, temperature and discharge for all station and water level fluctuations at the lag time of one year (RMSEs) of 0.23, 0.41 m obtained by SVM, NWN, respectively, and SSEs of 0.43, 1.33 and R ² of 0.97, 0 obtained by SVM, NWN, respectively. The results of SVM model show better accuracy in comparison with the NWN model.     

Transport of kinetically sorbing solutes in heterogeneous sediments with multimodal conductivity and hierarchical organization across scales

Solute transport in subsurface environments is controlled by geological heterogeneity over multiple scales. In reactive transport characterized by a low Damköhler number, it is also controlled by the rate of kinetic mass transfer. A theory for addressing the impact of sedimentary texture on the transport of kinetically sorbing solutes in heterogeneous porous formations is derived using the Lagrangian-based stochastic methodology. The resulting model represents the hierarchical organization of sedimentary textures and associated modes of log conductivity (K) for sedimentary units through a hierarchical Markov Chain. The model characterizes kinetic sorption using a spatially uniform linear reversible rate expression. Our main interest is to investigate the effect of sorption kinetics relative to the effects of K heterogeneity on the dispersion of a reactive plume. We study the contribution of each scale of stratal architecture to the dispersion of kinetically sorbing solutes in the case of a low Damköhler number. Examples are used to demonstrate the time evolution and relative contributions of the auto- and cross-transition probability terms to dispersion. Our analysis is focused on the model sensitivity to the parameters defined at each hierarchical level (scale) including the integral scales of K spatial correlation, the anisotropy ratio, the indicator correlation scales, and the contrast in mean K between facies defined at different scales. The results show that the anisotropy ratio and integral scales of K have negligible effect upon the longitudinal dispersion of sorbing solutes. Furthermore, dispersion of sorbing solutes depends mostly on indicator correlation scales, and the contrast of the mean conductivity between units at different scales.     

Impact of rapid urbanization on the modern sedimentary environments in a semienclosed embayment: Tong’an Bay,southeast China coast

Tong’an Bay (TAB) is a semienclosed embayment in the north of Xiamen Island. The sea area of TAB was mainly used for aquaculture in enclosed areas before 2003. Since 2003, the districts surrounding TAB have been undergoing a rapid urbanization process, and the scale of land used for urban construction in these districts has been continuously increasing. Under the backdrop of rapid urbanization, the coastline of TAB has largely been transformed into an artificial coastline. Due to the large scale of land reclamation and, dredging activities and the opening of the Gaoqi-Jimei (GJ) Seawall, there have been relatively significant changes in the coastal and submarine geomorphology in central northern, western, and southern TAB and Wuyuan Bay as well as a significant increase in the area where artificial submarine geomorphologies are distributed; the number of surface sediment types in the TAB has increased, and sediments in the sea area surrounding engineering projects have been coarsening; the sediment transport pattern has not significantly changed at the mouth of TAB and in central northern TAB, but the suspended sediment transport direction near the GJ Seawall has changed to a certain extent.     

Milgromian dynamics and dwarf galaxies in galactic voids

We use kinematic data of 103 dwarf galaxies, obtained from the Sloan Digital Sky Survey catalog, to test the Milgromian dynamics (MOND) inside a galactic void. From this data, we compute the line-of-sight velocity dispersions of the dwarf galaxies in the frameworks of MOND and Newtonian dynamics without invoking any dark matter. The prediction for the line-of-sight velocity dispersions from MOND of 53 selected dwarf galaxies is compared with their measured values. For appropriate mass-to-light ratios in the range 1 to 5 for each individual dwarf galaxy, our results for the line-of-sight velocity dispersions predicted by MOND are more compatible with observations than those predicted by Newtonian dynamics.     

A Novel Intelligent ELM-BBO Technique for Predicting Distance of Mine Blasting-Induced Flyrock

Natural Resources Research - Blasting is an economical technique for rock breaking in hard rock excavation. One of its complex undesired environmental effects is flyrock, which may result in human...