A Least-squares Approach to Shape Determination from Residual Self-potential Anomalies

—We have developed a least-squares minimization approach to determine the shape (shape-factor) of a buried polarized body from a residual self-potential anomaly profile. By defining the zero anomaly distance and the anomaly value at the origin on the profile, the problem of the shape-factor determination is transformed into the problem of finding a solution of a nonlinear equation of the form f(q) = 0. Procedures are also formulated to estimate the depth of polarization angle, and the electric dipole moment. The method is applied to synthetic data with and without random noise. The obtained shape-factor agrees very well with the model shape-factor when using synthetic data. After adding ± 2 percent random error in the synthetic data, the shape factor obtained is within ± 4 percent. Finally the validity of the method is tested on a field example from the Ergani copper district, Turkey.     

Nutrient distribution and fluxes from three Mediterranean coastal rivers (NE Algeria) under large damming

Nutrient distribution and fluxes into and from dams and into coastal waters from three rivers (NE Algeria) were assessed during a one-year period in three stations for each river: at the entrance and the exit of dam and at the outlet. The main characteristics of the rivers were the high levels of NH₄ and PO₄, even in dam entrances, contrarily to SiO₄ levels that are still low upstream the dams. From the inorganic nutrient incoming fluxes, the dams trapped annually 42 to 93%, depending on the nutrient, but released in great levels dissolved organic forms at their exits. At catchment scale, dissolved nitrogen loadings reach 338 kg/km²/yr, in which the organic fraction forms up to 34%; while those of dissolved phosphorus reach 172 kg/km²/yr, with a great organic fraction. The Si:N ratios decreased while N:P ratios increased at river outlets, indicating large inputs of N over P in the lower catchments.     

Assessment of organic pollutants (PAH and PCB) in surface water: sediments and shallow groundwater of Grombalia watershed in northeast of Tunisia

Toxic organic compounds in wastewater are serious threats for both human and environment healthy states. This study investigates the potential sources of surface water, sediment and groundwater pollution by polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyl (PCBs) as discharged by wastewater into the River of Oued El bey in northeastern Tunisia. Analysis indicates that the concentration of PAHs and PCBs are high in wastewater and vary from 0.37 to 0.83 mg/L and from 0.28 and 1.18 mg/L, respectively. The spatial distribution of PAHs and PCB in surface water showed a variation between 0.37 to 9.91 mg/L and between 0.1 to 0.47 mg/L, respectively. However, the quality of surface water is changed after wastewater evacuation at Oued Tahouna. The determination of PAH and PCB pollutants in groundwater shows a great interest in the development of water resources. The Concentration of these pollutants varying from 0.0204 to 1.93 mg/L and from 0.0052 to 0.196 mg/L, respectively. For PAH, analysis reveals also that naphtelene, fluorene, anthracene and chrysene are the most detected PAHs compounds in water and sediment samples while benzo[b]fluoranthene and benzo[a]pyrene are less present and in trace level. Higher concentrations of PAHs and PCBs are found in samples taken close to industrial areas of Bouargoub and Soliman, and wastewater discharge locations in Soliman. Analysis of the spatial distribution of PAHs and PCBs clearly link their higher concentration in water and sediments to wastewater and manufacturing discharges in the study area. In surface sediment, the organic pollutants are present. The cluster analysis for organic pollutants in different state and different matrix highlight a relationship between the wastewater evacuation and the water qualities which confirmed the direct response of the pollution sources on the surface water and groundwater organic pollution quality.     

Fusion Methods and Multi-classifiers to Improve Land Cover Estimation Using Remote Sensing Analysis

Geotechnical and Geological Engineering - Adopting a low spatial resolution remote sensing imagery to get an accurate estimation of Land Use Land Cover is a difficult task to perform. Image fusion...     

Formal solution of the asteroid motion near the 2:1 commensurability

In a previous paper (Ammar in Proc. Math. Phys. 77:99, 2002) the statement of the problem was formulated and the basic equations of motion were formed in terms of variables suitable for the applications in the problem of asteroid motion close to 2:1 commensurability. The short period terms has been eliminated up to the first order in masses O(μ), using a perturbation approach based on the Lie series, the problem is reduced to that of secular resonance one. In the present work the extended Delaunay method has been applied to develop the Hamiltonian and the generator as a power series in rather than the power of ε, where ε is a small parameter of order of the relative mass of the perturber. Hamilton–Jacobi method were used as a method of integration of the equations of the dynamical system in order to build a formal solution for the resonant problem of the type 2:1 with one degree of freedom.     

Vulnerability assessment of coastal areas to sea level rise from the physical and socioeconomic parameters: case of the Gulf Coast of Bejaia,Algeria

The study area (the Gulf of Bejaia) is a coastal zone of about 70 km long in the eastern-central part of the Algerian coast. The coastline characterized by sandy beaches, hotels and tourist facilities, airport, port, villages and towns has known during these last decades several threats like storms, floods and erosion. The present work concerns the mapping of the physical and socioeconomic vulnerability of the Gulf Coast of Bejaia to sea level rise, using Coastal Vulnerability Index (CVI) and geospatial tools. The Physical CVI (CVI_Phys) is calculated from seven physical variables: geomorphology, coastal slope, coastal regional elevation, sea level rise rate, shoreline erosion/accretion rates, tidal range and significant wave height. On the other hand, the parameters population, cultural heritage, roads, railways, land use and conservation designation constitute, for their part, the socioeconomic CVI (CVI_eco). The values obtained from the calculation of CVI_Phys vary between 3.53 and 81.83. These results revealed that 22.42 km of the studied coastline has a low physical vulnerability, 21.68 km a high vulnerability and 15.83 km a very high vulnerability, indicating that the most part of the coastline (53.59%) is vulnerable to sea level rise. According to the obtained values of CVI_eco, the most vulnerable areas of high and very high risk represent 31.81 km of the total coastline. They were found along the western (Bejaia and Tichy) and eastern (Aokas, Souk El Tenine and Melbou) coast, while the least vulnerable stretches, covering 38.19 km of the total length of the coast, occupy the rest of the area. This study highlighted areas that will be most affected by future sea level rise (SLR) and storm events. It revealed that several development projects of Bejaia Gulf Coast, including tourist expansion areas, are planned in sites identified as very vulnerable. The results obtained from this assessment could guide local planners and decision-makers in developing coastal management plans in the most vulnerable areas.     

Merging science into community adaptation planning processes: a cross-site comparison of four distinct areas of the Lower Mekong Basin

Climate change is increasingly affecting rural areas worldwide. The Lower Mekong Basin (LMB) is at particular risk due to heat stress, changing rainfall patterns, rising sea levels, and more frequent and extreme climatic events. It is imperative that local-level adaptation plans are developed in a manner that builds resilience to these growing threats. Strategies for developing adaptation plans tend to comprise predominantly science-led or predominantly community-led processes. This study examines an approach that balances inputs from both processes in characterizing community vulnerability as a component of the adaptation planning workflow. Evaluation sites are located within four distinct sub-regions of the LMB: the Vietnam Mekong Delta, the Annamite Mountains of Lao PDR, the Cambodia central lowlands, and the mid-elevation forests of northern Thailand. Our results indicate that by merging science-based data with community-level perspective, knowledge gaps from both sides are filled and a more comprehensive understanding of vulnerability is factored into adaptation planning.     

Rocking vibration of a rigid circular disc in a transversely isotropic full‐space

In this paper, forced rocking vibration of a rigid circular disc placed in a transversely isotropic full‐space, where the axis of material symmetry of the full‐space is normal to the surface of the plate, is analytically investigated. Because of using the Fourier series and Hankel integral transforms, the mixed boundary‐value problem is transformed into two separate pairs of integral equations called dual integral equations. The dual integral equations involved in this paper are reduced to Fredholm integral equations of the second kind. With the aid of contour integration, the governing integral equation is numerically evaluated in the general dynamic case. The reduced static case of the dual integral equations is solved analytically and the vertical displacement, the contact pressure and the static impedance/compliance function are explicitly determined, and it is shown that the pressure in between the plate and the full‐space and the compliance function reduced for isotropic half‐space are identical to the previously published solutions. The dynamic contact pressure in between the disc and the space and also the related impedance function are numerically evaluated in general dynamic case and illustrated. It is shown that the singularity exists in the contact pressure at the edge of the disc is the same as the static case. To show the effect of material anisotropy, the numerical evaluations are given for some different transversely isotropic materials and compared. Copyright © 2010 John Wiley & Sons, Ltd.