A case study of foundation failure of a residential building: From diagnosis to reparation

The pathology that appears in reinforced concrete structures, old and new, is inevitable and involves all stakeholders at all levels of responsibility, from the technician to the decision maker at the highest level. It also concerns engineers from design offices and experts from offices responsible for diagnosing existing structures, as well as engineers from repair companies. Like all countries in the world, the study of the pathology and safety of civil engineering buildings is one of the big problems encountered in the field of construction in Algeria. The foundations are among of the structural elements of the buildings most affected by this damage, these constitute the link between the structure and the soil, they allow the transmission of loads from the structure to the soil. If these structural elements are damaged, they affect the general stability of the building. Depending on the severity of the damage, it can cause the building collapse. The main objective of this paper is to study a pathological case of foundation failure of a residential building: from diagnosis to reparation. This repair was carried out according to an intervention plan comprising stages spread over time, this allowed the strengthening of the infrastructure and gave the building an acceptable level of security

Evaluating morphological variability of Artemisia herba-alba Asso from western Algeria

This work was interested on the study of the morphological variability of 120 individuals of Artemisia herba-alba Asso coming from three stations in western Algeria , which was assessed through 15 quantitative and qualitative characters. Analysis of variance (ANOVA) and hierarchical cluster analysis (HCA) results showed significant morphological variability inter and intra-population. This phenotypic variability is explained by a high genetic polymorphism determined at another genetic study that we conducted in parallel on individuals of the same site using molecular markers types ISSR.This study also revealed a large variability within A. herba alba which could help investigation on a large collection of individuals and therefore select the most efficient ecotypes for re-introduction this species in steppes and highlands of Algeria.Key words: Artemisia herba-alba Asso; Morphological variability;steppe;Algeria

3D NUMERICAL STUDY OF MAGNETOHYDRODYNAMIC INSTABILITY IN LIQUID METAL TAYLOR-COUETTE FLOW

This purpose is about a 3D study of magnetohydrodynamic (MHD) instability in liquid matal Taylor-Couette flow, this problem is receiving more and more research interest due to its application in the engineering, oceanography and the astrophysical research The Taylor-Couette system consists of two coaxial cylinders in differential rotation, which is considered as a hydrodynamic model system, allowed researchers to progress in understanding the laminar-turbulent transition phenomena. A set of states found in narrow gap of Taylor-Couette systems where the outer cylinder is held fixed and the inner cylinder speed increased. The symmetry breaking parameter is the Taylor number Ta that gives a measure of the ratio of centrifugal forces to viscous forces. When the liquid is replaced by an electrically conducting fluid and an external magnetic field is applied, this leads to MHD Taylor-Couette flow. Additional body force, Lorentz force, acting on the fluid arises. Lorentz force is in the direction perpendicular to both magnetic and electric fields. The behaviour of flow depends on strength and geometry of applied field, magnetic and electric properties of the liquid, cylinders and endplates. In this work, the MHD instability Taylor-Couette flow is considered for liquid sodium with its magnetic Prandtl number Pm <1. The results of pressure and angular momentum in the Taylor-Couette flow under the effect of an external uniform axial magnetic field B=4 Tesla are investigated numerically for the different cases of electrically conducting or insulating walls at the Ekman cell, at the middle of the first Taylor-votex flow (TVF) and between two cells

Preparation of superhydrophobic and self-cleaning polysulfone non-wovens by electrospinning: influence of process parameters on morphology and hydrophobicity

Electrospinning is used to prepare hydrophobic and self-cleaning polysulfone (PSf) surfaces. The effects of PSf concentration in Dimethylformamide (DMF) solvent and electrospinning process parameters on the surface structure and hydrophobicity are investigated. The experimental results show that depending on PSf concentration, three types of morphologies are obtained: beads, beads-on-strings, and free-beads fibers. The surface hydrophobicity depends mainly on the resultant surface morphology, and the existence of beads increases hydrophobicity. The contact angle (CA) is found to increase from 73° for smooth PSf surface to more than 160° for surfaces formed by electrospinning. Moreover, the contact angle hysteresis (CAH) was generally less than 10° for all the chemistries. It is noted that increasing the PSf concentration leads to the formation of beads-on-string and free-beads fiber structures; this morphological change is accompanied by a reduction in the contact angle. Surface structures are found to be more sensitive to electrospinning feed rate than to electrospinning voltage; however, these two parameters have a negligible influence on the hydrophobicity. Porosity measurements of different chemistries show an average pore size in the range 3–8 microns. The thickness of PSf mats was variable, from as low as 10 μm to as high as 70 μm.King Fahd University of Petroleum and Minerals (KFUPM-MIT Project No. R16-DMN-11)King Abdulaziz City of Science and Technology (Saudia Arabia) (Project No. 11-ADV2134- 04

Hypoglycemic and antihyperglycemic effects of Anabasis articulata (Forssk) Moq (Chenopodiaceae), an Algerian medicinal plant

Anabasis articulata leaves decoction is widely used by Algerian traditional medicine practitioners as a remedy for the treatment of diabetes. The aqueous extract was found to be non-toxic at 1000 mg/kg, asno deaths or hazardous signs were recorded during treatment or the observation period (24 and 72 h) in either control or treated groups of mice. Experiments were performed in non-diabetic mice, and inhyperglycemic mice (glucose treated and alloxan treated mice) to confirm the antidiabetic potential of A. articulata. Our results showed that the orally administration at a dose of 400 mg/kg decreased the glycaemia by 29.89% after 6 h (p < 0.05), corresponding to the greatest decrease of blood glucose in normoglycaemic mice. This dose also lowered blood glucose concentrations in diabetic mice revealing antihyperglycemic effect of A. articulata leaves. The class of phytochemical responsible for antidiabetic effects in aqueous leaf extract was also investigated. Phytochemical screening showed that the aqueous extract contains alkaloids (1.25%) and saponin (1.30%). Our findings showed that saponin (5 mg/Kg) was the active fraction, since it restores the normal blood glucose levels after 21 days of treatment. The alkaloid fraction did not significantly reduce the blood glucose level. The present studyconfirms the antidiabetic proprieties of A. articulata leaves previously reported by Algerian healers

FINITE ELEMENT INVESTIGATION OF INITIAL CLEARANCE EFFECT ON TUBE-TO-TUBESHEET JOINT STRENGTH

The tube-to-tubesheet joint strength is measured in terms of residual contact pressure between the tube’s outer surface and tubesheet hole surfaces. The joint integrity is affected by several design parameters, including the type of material and the initial radial clearance. To avoid weakening of joints due to excessive initial radial clearances Tubular Exchanger Manufacturer Association (TEMA) has set standards in which maximum over-tolerances are spelled out. The present work complements the experimental program on the effect of over-tolerance on heat exchangers tube-to-tubesheet joint strength. The finite element analysis first addressed the ligament effect on the residual stress in order to select a satisfactory sleeve diameter. Second, the initial clearance effect on contact pressure and percent tube wall reduction is performed. Results show that for low strain hardening materials the initial clearance effect is negligible. However, higher levels of strain hardening have a significant effect on residual stress and percent wall reduction. For low clearances, the finite element estimated residual contact pressure compared well with the analytical result and that inferred from the experimentally measured pull-out force. The variation of the percent wall reduction with initial clearance is found to be similar to that of the measured one

What can crop stable isotopes ever do for us? An experimental perspective on using crop carbon stable isotope values for reconstructing water availability in semi-arid and arid environments

This study re-assesses and refines the use of crop carbon stable isotopes (Δ13C) to reconstruct past water availability. Durum wheat, six-row barley, and sorghum were experimentally grown at three crop growing stations in Jordan for up to three years under five different irrigation regimes: 0% (rainfall only), 40%, 80%, 100%, and 120% of the crops’ optimum water requirements. Results show large variation in carbon stable isotopes for crops that received similar amounts of water, either as absolute water input or as percentage of crop requirements. We conclude that C3 crop carbon stable isotope composition can therefore be best interpreted in terms of extremely high values showing an abundance of water versus low values indicating water-stress. Values in between these extremes are problematic and best interpreted in conjunction with other proxies. C4 crop isotopes were not found to be useful for the reconstruction of water availability