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The objective of this study was to create a new material utilizing a biopolymer (sodium alginate) and the powder of brown algae for the elimination of organic pollutants like dyes by adsorption from a water-based solution. The alginate/algae composite beads used in this study as an adsorbent were created by inotropic gelation of sodium alginate utilizing calcium ions as cross-linking agent. The beads thus synthetized had been characterized by different techniques in order to assess their characteristics. The adsorption procedure was studied in a batch mode at room temperature using methyl violet, a cationic dye chosen as an organic pollutant. The influence of beading parameters like contact time, methyl violet concentration, pH, sorbent amount and speed agitation was studied. It was found that the adsorption capacities were notably influenced by the initial dye concentration, pH and beads dose. Indeed, the results found indicated that the equilibrium sorption of methyl violet by this adsorbent was reached in around 3 hours for the different concentrations studied (10 mg/L, 40 mg/L and 70 mg/L) with percentage dye removal of around 80% at the optimum bead amount of 2 g. The kinetic modeling had shown that the model of the pseudo-second-order kinetic governed the adsorption rate of methyl violet on alginate/brown algae composite beads.

The presence of a geometric discontinuity such as a crack or a notch can cause the failure of a structure during its use. Under various mechanical or thermal stresses, a high concentration of stresses can take place at the level of these discontinuities, which in most cases will lead to the total failure of the structure. The service life of these structures can be improved with the use of the repair technique by bonding a composite patch. This technique is of significant interest in several fields, especially with the use of composite materials. This technique is widely used in aeronautics and ensures a long life of damaged structures. Current research aims to optimize the shape size and fiber's nature of this composite patch in order to ensure good load transfer by reducing the stresses in the damaged area. In this work, a finite element method is used to analysis the effect of the shape of the patch on the global response of a 2024-T3 aluminum structure in the presence of a central circular notch. The composite patch is of the carbon/epoxy type bonded through an A-140 Adekit type adhesive on the damaged part of the plate. The analysis consists in determining the force-displacement curves of the repaired structure by using the combination of the two techniques, XFEM for the damage of the aluminum plate 2024-T3 by the automatic creation of the crack and CZM for the analysis of the adhesive debonding. The analysis takes into account the damage in the plate and in the adhesive. However, for the composite patch, and since there will be no damage, we have just analyzed the effect of its shape and essentially the shape of its edges on the load transfer and consequently on the resistance of the structure under loading in tension. Two main patch shapes have been highlighted, namely the square and circular shape. The results show clearly that the shape of the patch�s edges has an impact on the stresses reduction in the plate and subsequently ensures good resistance in terms of force-displacement curve and consequently delays the peeling of the adhesive

Background: Over-crowded surgical trays result in perioperative inefficiency and unnecessary costs. While methodologies to reduce the size of surgical trays have been described in the literature, they each have their own drawbacks. In this study, we compared three methods: (1) clinician review (CR), (2) mathematical programming (MP), and (3) a novel hybrid model (HM) based on surveys and cost analysis. While CR and MP are well documented, CR can yield suboptimal reductions and MP can be laborious and technically challenging. We hypothesized our easy-to-implement HM would result in a reduction of surgical instruments in both the laminectomy tray (LT) and basic neurosurgery tray (BNT) that is comparable to CR and MP. Methods: Three approaches were tested: CR, MP, and HM. We interviewed 5 neurosurgeons and 3 orthopedic surgeons, at our institution, who performed a total of 5437 spine cases, requiring the use of the LT and BNT over a 4-year (2017–2021) period. In CR, surgeons suggested which surgical instruments should be removed. MP was performed via the mathematical analysis of 25 observations of the use of a LT and BNT tray. The HM was performed via a structured survey of the surgeons’ estimated instrument usage, followed by a cost-based inflection point analysis. Results: The CR, MP, and HM approaches resulted in a total instrument reduction of 41%, 35%, and 38%, respectively, corresponding to total cost savings per annum of $50,211.20, $46,348.80, and $44,417.60, respectively. Conclusions: While hospitals continue to examine perioperative services for potential inefficiencies, surgical inventory will be increasingly scrutinized. Despite MP being the most accurate methodology to do so, our results suggest that savings were similar across all three methods. CR and HM are significantly less laborious and thus are practical alternatives.

The presence of a geometric discontinuity such as a crack or a notch can cause the failure of a structure during its use. Under various mechanical or thermal stresses, a high concentration of stresses can take place at the level of these discontinuities, which in most cases will lead to the total failure of the structure. The service life of these structures can be improved with the use of the repair technique by bonding a composite patch. This technique is of significant interest in several fields, especially with the use of composite materials. This technique is widely used in aeronautics and ensures a long life of damaged structures. Current research aims to optimize the shape size and fiber's nature of this composite patch in order to ensure good load transfer by reducing the stresses in the damaged area. In this work, a finite element method is used to analysis the effect of the shape of the patch on the global response of a 2024-T3 aluminum structure in the presence of a central circular notch. The composite patch is of the carbon/epoxy type bonded through an A-140 Adekit type adhesive on the damaged part of the plate. The analysis consists in determining the force-displacement curves of the repaired structure by using the combination of the two techniques, XFEM for the damage of the aluminum plate 2024-T3 by the automatic creation of the crack and CZM for the analysis of the adhesive debonding. The analysis takes into account the damage in the plate and in the adhesive. However, for the composite patch, and since there will be no damage, we have just analyzed the effect of its shape and essentially the shape of its edges on the load transfer and consequently on the resistance of the structure under loading in tension. Two main patch shapes have been highlighted, namely the square and circular shape. The results show clearly that the shape of the patch’s edges has an impact on the stresses reduction in the plate and subsequently ensures good resistance in terms of force-displacement curve and consequently delays the peeling of the adhesive.

OpenStreetMap (OSM) is a collaborative project to create a free and editable map of the world. You can think of OSM as the 'Wikipedia' of cartography. An important geospatial component of this database is the road network quality, which is important for applications such as routing and navigation.The objective of this work is the geometric enhancement of the OSM road network using a standard national map as a reference. We use two transformation methods, the global transformation and the local transformation (Delaunay triangulation).This study aims to present a new approach to improve the OSM road network geometrically. To this end, we present a three-step approach based on two techniques that leads to the enhancement of the geometric accuracy of the OSM road network. The first step is the global transformation of the OSM road network. The second step consists of applying the local transformation (Delaunay triangulation) on the OSM road network. In the last step, a comparison between the two methods is examined by calculating the mean and the standard deviation of the checkpoints in order to justify which is the best technique for the geometric enhancement of the OSM road network. We will be particularly interested in the application of this approach in the geometric enhancement / correction where each node of the OSM network will have a newly calculated position. Both approaches have been tested in the region of Oran in Algeria as testing example. The reference data is a city map produced by the National Institute of Cartography and Remote Sensing (INCT) in 2006. The proposed techniques show a clear improvement in geometric accuracy.

Understanding the mechanical and rupture behavior of orthopedic cement fixing the cup of a total hip prosthesis (THP) to cortical bone is crucial for comprehending the conditions governing prosthesis stability and potential loosening. Consequently, this study employs a three-dimensional finite element method to investigate the mechanical behavior of cement with interfacial cracks at the junction between the cement and cup. Through stress distribution analysis, we identify the initiation points of cracks and examine how stress intensity factors (SIFs) vary across three modes of failure (I, II and III) throughout a walking cycle, particularly concerning the femoral head. Our findings reveal that loading stages cause stable variations in SIFs along the crack front, with the highest values consistently at the second end of the crack. Moreover, the propagation mechanism of interfacial cracks is complex, oscillating between modes of opening and plane shear, linked to the SIFs of modes I and II and the material properties of the cement and cup. Furthermore, mode III behavior mirrors that of mode II, with nearly linear increases in SIFs along the crack front, peaking near the crack’s terminus. Overall, mode III (out-of-plane shear) emerges as the primary fracture mode, indicating a risk of damage to the reconstructed acetabulum from fatigue, despite the SIF values being lower than the fracture toughness of both the cup and the cement. [ABSTRACT FROM AUTHOR]

As part of ecotoxicological tests on anuran tadpoles, we propose to study the sensitivity of different stages towards a nitrogenous compound frequently used in Morocco (Ammonium sulphate). For this, acute toxicity tests on tadpoles of two species (Bufo mauritanicus and Rana ridibunda) belonging to different stages of development were carried out. The lethal effects after 96 hours caused by a pollutant used as a reference (potassium dichromate) as well as ammonium sulphate increase with concentration and vary according to the stage of development. Significant differences were observed in the sensitivity of tadpoles to pollutants according to the stage of development. Tadpoles belonging to the early stages of development (stage 24 according to Gosner, 1960) show greater acute effects on pollutants than tadpoles belonging to the advanced stages of development (Stage 36 according to Gosner, 1960). After 96 hours, the lowest effective concentration (LOEC) is observed in tadpoles belonging to the early stages of development (Stage 24 according to Gosner, 1960) in Rana ridibunda exposed just to the lowest concentration used (20 mg / l of ammonium sulphate). Therefore, ammonium sulphate may play a role in the local decline of amphibians.

Algeria faces challenges of globalization. It classifies the establishment of the national general urban and rural territory cadastre as top priority. The National Cadastre Agency has implemented a policy aimed at improving the quality and accuracy of the resulting documentation, in order to widen the scope of the latter in the various fields.Since the launching of the first operations to establish the general cadastre of the national territory, the graphic cadastral documentation which was carried out based on aerial images (ortho-photographs or restitution plans) present mismatch either between the external borders or between the section plans that compose the communal (municipal) cadastral plane.This article describes one of the simultaneous plane adjustment techniques inspired by the aero triangulation used in photogrammetry. In a first step, we built the photogrammetric unit where we consider the cadastral planes as photogrammetric models. In a second step, the constructed units will be used to form a superstructure covering a very large area like in the photogrammetric block case. Finally, this superstructure is adjusted, where the discrepancies are reduces relatively between these section plans using Tie Points (TP) and absolutely by relying on an optimal number of Ground Control Points (GCP) in the terrain system suitably distributed on the block.This technique makes it possible to preserve the relationships between the data in a precise way and to guarantee the continuity in the acquisition of the data which can be added later. It also makes it possible to solve the problem of the overlap between the isolated section plans due to the non-optimal distribution, the insufficiency, or the absence of control points.The evaluation results obtained after the experiments report that the proposed adjustment technique is efficient to solve such a problem.

Polymers are known to be sensitive to aging; their lifetime can be predicted through experimental tests. This paper displays an experimental study on the long-term performance of polymethyl methacrylate (PMMA) exposed to solar (UV) radiations and artificial (UV) lamp radiations, drinking water and sea water. The performance of this polymer was analyzed in terms of strain variation; strain at break in tension, and Young's modulus. The results obtained showed that the amount of absorbed water is independent of the nature of the solvent, and only the absorption kinetics may be regulated by the species contained in the medium. This seems to indicate that plastification of polymers is a reversible phenomenon. In addition, it was found that the tensile strength and elastic modulus drop with increasing immersion time. Compared with seawater, the absorption of drinking tap water, after 36 months, leads to a non-linear behavior of the polymethyl methacrylate. Exposition of PMMA to artificial (UV) lamp radiations and solar (UV) radiations, for the same duration of exposure, resulted in greater performance degradation when the polymer was exposed to artificial (UV) lamp radiations. In addition, the results obtained after a 19 month exposure period that the artificial (UV) lamp radiations changes the behavior of this material from viscoelastic to viscoplastic

In this work the finite element method (FEM) was used to analyze the mechanical behavior of the composite materials subjected to the mechanical loading. This behavior is studied in terms of stress intensity factor variation as a function of the applied stress intensity. The residual stresses induced in the composites, during the elaboration of these composites are taken into consideration in this study. The superimposition of these types of stresses (residuals and commissioning) is simulated here by thermomechanical stresses. The results obtained show that in the vicinity very close to the fiber-matrix interface and under the effect of this loading type, the matrix cracks propagate in modes I, II and III, and far from the interface, in mode I. The propagation kinetics is slowed down by the interface-crack interaction. The effects of the crack size, the orientation and propagation of the crack, commissioning stresses, the elaboration temperature, fiber physical properties, matrix stiffness and thermomechanical stresses have been highlighted in this work.

Une utilisation non raisonnée des engrais et des pesticides nuit à l’environnement et en particulier aux sources d’eau ainsi qu’à la santé de l’être humain à travers la nourriture. Dans le cadre de la surveillance des eaux de surface marocaine, on a réalisé une enquête auprès de 100 agriculteurs à El Gara, province de Berrechid (Région Casablanca-Settat). Tous les agriculteurs consultés utilisent les engrais et les pesticides. 75% des interviewés ignorent le mode d’emploi de ces produits. Les pesticides sont utilisés une fois par an par 44% des agriculteurs, 70% les appliquent par l’intermédiaire de pick up ou de tracteur, 3% les manipulent en mettant des habits spéciaux et 27% le font à mains nues. Pour les engrais, les agriculteurs les utilisent une fois par an à des proportions variables en ne se basant que sur leur propre expérience. Ainsi, l’Ammonitrate 33,5%N est utilisé par 98% des agriculteurs à une moyenne de 130,9 Kg/ha, le NPK 10-30-10 utilisé par 95% à une moyenne de 175 Kg/ha, le Sulfate d'ammoniaque 21%N est utilisé par 66% à une moyenne de 121,9 Kg/ha et finalement l’Urée 46%N est utilisée par 46% à une moyenne de 67,9 Kg/ha. Ces pratiques ne sont pas soutenables à long terme car elles vont nuire à l’équilibre des écosystèmes en provoquant des dommages à l’environnement et agir sur la santé humaine d’où l’intérêt des agricultures durables. Mots clés: Engrais, pesticides, agriculteurs, enquête