Sedimentology and depositional environments of the Ordovician Umm Sahm Sandstone Formation in southern Jordan

The Ordovician Umm Sahm Sandstone Formation of Jordan comprises approximately 200-m-thick succession of fluvial quartzarenites with subordinate claystone and siltstone lithologies of shallow marine conditions. The Umm Sahm Formation is characterized by its dark brown color, frequent jointing, and steep scarps. The Umm Sahm Formation is bounded by the marine claystones of Hiswah Formation at the top and the fluvial sandstones of the Disi Formation at the bottom. The Umm Sahm Formation is composed of two main facies: fluvial facies and tidal facies. The fluvial facies constitutes about 93% of the total thickness. The lower few meters of the succession passes upward from the Disi Sandstone Formation into similar massive white sandstone facies exhibiting similar white color, fine- to coarse-grained sandstone, with round-shaped pebbles. Trough and planar cross-bedding show a northwest unidirectional palaeocurrent trend. Light brown colored quartzarenites similar to those of the Cambrian Umm Ishrin Sandstone Formation are most common in the upper part of the succession. The tidal facies occupies three intervals in the middle part of the succession. It is composed of laminated and thin-bedded sandstones, siltstones, and claystones. They are rippled and varicolored with abundant trace fossils (Cruziana, Harlania, ruzophycus). The presence of hummocky cross stratification indicates the earliest short-lived tempestite conditions during the Paleozoic erathem of Jordan. The first appearance of Graptolites in the Ordovician rocks of Jordan was recorded during this study in the tidal facies of the Umm Sahm Formation. The vertical arrangement of both fluvial and tidal facies indicates three successive short-lived transgressions and regressions. These marine incursions indicate the successive shoreline advances of the Tethys Ocean, which was located northward, and inundated the southern braid plain. The three short-lived transgressive events took place, and the Tethys marine margin was displaced southward, giving rise to deposition of tidal facies in an open coast tidal flat. Following the transgressive events, renewed progradation and strandline retreat took place, fed by large amounts of siliciclastics derived from the continent and transported by braided streams across the intertidal zone.     

Comprehension and hydrogeological conceptualization of aquifer in arid and semi-arid regions using integrated hydrogeological information system: case of the deep aquifer of Zéramdine-Béni Hassen (east-central Tunisia)

In arid and semi-arid regions, the groundwater overexploitation caused drawdown in piezometric levels and a degradation of chemical water quality. That is why the groundwater monitoring needs a good comprehension of the hydrogeological aquifer properties. This is specially the case of Zéramdine–Béni Hassen deep aquifer (east-central Tunisia). Seismic profiles interpretation highlights the existence of the Zéramdine fault corridor, the Boumerdès anticline, the Moknine and Mahdia grabens that represent lateral boundaries for the study aquifer. The outcrop of the aquifer is located in the Zéramdine, Béni Hassen and Ain Ben Jannet regions, where two lithostratigraphic sections were realized. The piezometric study shows that the principal groundwater flow is from west to east. A secondary flow is from NW to SE. The hydrochemical study of 22 sample shows that the aquifer is characterized by freshwater, dominated by Na–Ca–Cl–SO4 facies. The salinity increase is from the west to the east, which coincides with the principal water flow direction. The integration of all results deduced from the hydrogeophysic, hydrodynamic and hydrochemical studies is developed to investigate hydrological processes of Zéramdine–Béni Hassen aquifer and consequently to propose a conceptual model, which will help to propose a rescue plan for the studied aquifer and to implement a spatial hydrogeological database using the global information system and then to characterize the complex aquifer system.     

Mineralization of Catechol by Fenton and Photo‐Fenton Processes

Catechol is one of the most abundant phenolic components of olive mill wastewaters. In this article, the mineralization of this compound in synthetic aqueous solutions by the Fenton and photo‐Fenton processes is studied. It has been found that for 1.44 mM catechol, the total organic carbon of solutions is reduced about 94.4% at best after 60 min of Fenton treatment at optimized conditions of pH 3.0, 0.2 mM Fe²⁺, 7.09 mM H₂O₂, and 25°C. A faster and overall mineralization is attained by applying photo‐Fenton with UVA irradiation. o‐Benzoquinone, 1,2,3‐trihydroxybenzene and 1,2,4‐trihydroxybenzene were identified by GC–MS as primary quinonic and polyhydroxylated derivatives. Small amounts of generated carboxylic acids like muconic, maleic, malonic, acetic, oxalic, and formic acids were detected by ion‐exclusion chromatography. The Fe(III) complexes of these acids persist in the medium under Fenton conditions, while their photolysis by UVA light and that of other by‐products account for by the faster degradation and total mineralization achieved in the photo‐Fenton process. A reaction sequence for catechol mineralization by Fenton and photo‐Fenton involving all intermediates detected is proposed.     

Shear reinforcement effect of reinforced concrete tie-columns on the lateral resistance of confined masonry walls

Tie-columns improve significantly the lateral resistance of masonry bearing walls against persistent, transient and accidental loads. The research work described herein has been carried out to assess the lateral resistance of confined masonry walls, where contribution of the masonry panel is evaluated according to material mechanics and tie-columns effect is estimated by a proposed analytical formulation based on a model reported on previously. This approach takes into account the effect of dowel support on the reaction of its adjacent shear reinforcement: the conditions for the various contributions of transverse reinforcements are better defined following a clear evaluation of the participation ratio of these reinforcements. Lateral resistances of confined masonry walls measured in full-scale tests and gleaned from the literature are compared and checked with resistances calculated using the present approach.     

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.