Satellite-based rainfall estimation and discharge measurement of Middle Indus River,Pakistan

The impacts of floods and droughts are intensified by climate change, lack of preparedness, and coordination. The average rainfall in study area is ranging from 200 to 400 mm per year. Rain gauge generally provides very accurate measurement of point rain rates and the amounts of rainfall but due to scarcity of the gauge locations provides very general information of the area on regional scale. Recognizing these practical limitations, it is essential to use remote sensing techniques for measuring the quantity of rainfall in the Middle Indus. In this research, Tropical Rainfall Measuring Mission (TRMM) estimation can be used as a proxy for the magnitude of rainfall estimates from classical methods (rain gauge), quantity, and its spatial distribution for Middle Indus river basin. In order to use TRMM satellite data for discharge measurement, its accuracy is determined by statistically comparing it with in situ gauged data on daily and monthly bases. The daily R ² value (0.42) is significantly lower than monthly R ² value (0.82), probably due to the time of summation of TRMM 3-hourly precipitation data into daily estimates. Daily TRMM data from 2003 to 2012 was used as input forcing in Soil and Water Assessment Tool (SWAT) hydrological model along with other input parameters. The calibration and validation results of SWAT model give R ² = 0.72 and 0.73 and Nash-Sutcliffe coefficient of efficiency = 0.69 and 0.65, respectively. Daily and monthly comparison graphs are generated on the basis of model discharge output and observed data.     

The effect of solar radiation pressure on the Lagrangian points in the elliptic restricted three-body problem

In this paper the effect of solar radiation pressure on the location and stability of the five Lagrangian points is studied, within the frame of elliptic restricted three-body problem, where the primaries are the Sun and Jupiter acting on a particle of negligible mass. We found that the radiation pressure plays the rule of slightly reducing the effective mass of the Sun and changes the location of the Lagrangian points. New formulas for the location of the collinear libration points were derived. For large values of the force ratio β, we found that at β=0.12, the collinear point L₃ is stable and some families of periodic orbits can be drawn around it.     

FEM Simulations of Granular Matter Behaviour Under Triaxial Tests

This article presents the results of a numerical simulation carried out from a series of standard triaxial tests conducted on limestone sand from a quarry situated in Algiers (center of Algeria). The main objective of the investigation is to obtain from a numerical analysis a simple soil model to represent the behaviour of the studied material. The 2D Plaxis program is used in this study with the introduction of a model based on the work of Brinkgreve et al. (in: Benz T, Nordal S (eds) Numerical methods in geotechnical engineering, CRC Press, Boca Raton, 2010). Corrections were made to the formulas used, which are based on the relative density, in order to improve the quality of the results in terms of soil behaviour, mechanical strength and deformation. The comparison of the experimental and numerical results for the Mohr–Coulomb model gives a considerable appreciation on the deformation and resistance. However, it fails to represent properly the stress–strain curve. The use of Duncan and Chang model (Hardening Soil Model-HSM) leads to an underestimation of the resistance characteristics (values of the friction angles) with an overall error of 7.98%. Our work consists of the application of two corrections to the HSM model. The first correction is based on the work of Brinkgreve et al. (2010), which focused on the common parameters between the HSM and the HSSM. An overestimation of the deformations was observed with an overall error of 155.96%. The second step consists of canceling the correction of the elastic modules (\(E_{50}^{ref}\), \(E_{oed}^{ref}\)) which reduces the error to 1.53%.

     

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.     

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.     

Detailed ground radiometric surveys on Gabal El Sela,Southeastern Desert,Egypt

Gabal El Sela area lies in the extreme southeastern part of the eastern desert in Egypt. It is covered by basement rocks of different compositions. The detailed work in this area covers about 4 km² and it is represented mainly by coarse younger granite as a curved shape extended in NE–SW direction and dissected by many faults in various trends; some of them are invaded by dykes especially the lamprophyre dykes in the ENE–WSW trend. Detailed geological, structural, and radiometric investigations are carried out on the area. The radiometric data are statistically analyzed and the results show that the total count radiometric map reflects six separate anomalies. The field work revealed that four anomalies are related to lamprophyre dykes, the other two anomalies are structurally controlled by NE–SW and E–W faults. These anomalies are followed by some trenches which traced and measured in detail exhibiting the possible extension of these anomalies with depth. These measurements show that lamprophyre dyke has the highest reading of radioactivity, it reaches 270 Ur in the surface and to 6,300 in the trenches. While the granite of the sela area is considered possesses high level of radioactivity, where its radioactivity ranges from 19.9 to 81 Ur with an average of about 32 Ur.     

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.     

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.