Recycling of rubber waste in sand concrete

The large development in the consumption of rubber is observed in the recent years, which leads to an increase of the production of rubber related waste. Rubbers are not hazardous waste, but they constitute a hazard for both environment and health, in case of fire in storage sites. So, recycling appears as one of the best solutions for disposing of rubber waste.This paper presents an experimental investigation dealing with the valorisation of rubber waste, specifically rubber obtained from old shoes sole waste. The waste rubbers are used form (0/5 mm) to mixes as addition at percentage (10%, 20%, 30% and 40%) in sand concrete. The physical (workability, bulk density), mechanical (compressive and flexural strength) and thermal properties are studied and analysed.The results indicate that the incorporation of rubber waste particles in sand concrete contributes to increase the workability and reduce the bulk density of all studied sand concrete. The obtained results show that mechanical performance (compressive and flexural strength) decreases when the rubber content increases. Nevertheless, the presence of rubber aggregate leads to a significant reduction in thermal conductivity, which improves the thermal insulation performances of sand concrete. This study insures that reusing of recycled rubber waste in sand concrete gives a positive approach to reduce the cost of materials and solve some environmental problems

Interféromètre de type Mach-Zehnder en silicium poreux : application aux biocapteurs

International audienceDans cette étude est présentée la réalisation et la caractérisation d'un guide d'ondes optique enterré et anti-résonant à base de silicium poreux. Ce guide d'ondes est intégré dans une structure interférométrique de type Mach-Zehnder qui sera utilisée pour une application de biodétection. Les simulations et les caractérisations optiques montrent clairement le guidage monomode ainsi que le caractère anti-résonant des guides d'ondes enterrés

Functionalization control of porous silicon optical structures using reflectance spectra modeling for biosensing applications

International audienceModeling and experimental reflectance spectra of porous silicon single layers at different steps of functionalization and protein grafting process are adjusted in order to determine the volume fraction of the biomolecules attached to the internal pore surface. This method is applied in order to control the efficiency of the chemical functionalization process of porous silicon single layers. Using results from single porous silicon layer study, theoretical microcavity is simulated at each step of the functionalization process. The calculated reflectance spectrum is in good agreement to the experimental one. Therefore the single layers study can be applied to multilayer structures and can be adapted for other optical structures such as waveguides, interferometers for biosensing applications

Buried Anti Resonant Reflecting Optical Waveguide based on porous silicon material for an integrated Mach Zehnder structure

International audienceA buried Anti Resonant Reflecting Optical Waveguide for an integrated Mach Zehnder structure based on porous silicon material is achieved using a classical photolithography process. Three distinct porous silicon layers are then elaborated in a single step, by varying the porosity (thus the refractive index) and the thickness while respecting the anti-resonance conditions. Simulations and experimental results clearly show the antiresonant character of the buried waveguides. Significant variation of the reflectance and light propagation with different behavior depending on the polarization and the Mach Zehnder dimensions is obtained. Finally, we confirm the feasibility of this structure for sensing applications

Structure des communautés d’ennemis naturels de Thaumetopoea pityocampa Denis & Schiffermüller (Lep., Thaumetopoeidae) sur pin d’Alep en Algérie

THE NATURAL ENEMIES COMMUNITIES STRUCTURE OF THAUMETOPOEA PITYOCAMPA DENIS SCHIFFERMÜLLER (LEP., THAUMETOPOEIDAE) ON PINUS HALEPENSIS IN THE SUBSAHARAN ALGERIA The host plants of the pine processionary caterpillars, Thaumetopoea pityocampa (Den. and Schiff.) (Lep., Thaumetopoeidae), are the Pinus and Cedrus. This study was carried out in the forest of Pinus halepensis Mill. in the subsaharian region where this insect pest was in a permanent presence. The structure of the natural enemies complex of this insect is analysed. Data on incidence of the various parasitoïds and predatory species are estimed. It appears that the majority of the entomophagous species attacking the pine processionary caterpillars were met in the studied area. It seems that the specific parasitoïds of different development stages, i.e. Baryscapus servadeii for eggs, Phryxe caudata, Erigorgus, femorator for the caterpillars, and, Villa brunnea for the pupae have a hight incidence in the regulation of the pine processionary caterpillars populations. It can exceed 80 % in certain pupae sites. However, in the subsaharian pine forest, predation by Scolopender was observed against the caterpillars in the pupal sites and hedgehog attacking the adults. These observations were not recorded in the other localities in the Mediterranean basin. Key words: Lepidoptera, insect forest pest, parasitism, incidence, Mediterranean basin

Towards a biosensor based on Anti Resonant Reflecting Optical Waveguide fabricated from porous silicon.

International audienceRecently, we demonstrated that Anti Resonant Reflecting Optical Waveguide (ARROW) based on porous silicon (PS) material can be used as a transducer for the development of a new optical biosensor. Compared to a conventional biosensor waveguide based on evanescent waves, the ARROW structure is designed to allow a better overlap between the propagated optical field and the molecules infiltrated in the porous core layer and so to provide better molecular interactions sensitivity. The aim of this work is to investigate the operating mode of an optical biosensor using the ARROW structure. We reported here an extensive study where the antiresonance conditions were adjusted just before the grafting of the studied molecules for a given refractive index range. The interesting feature of the studied ARROW structure is that it is elaborated from the same material which is the porous silicon obtained via a single electrochemical anodization process. After oxidation and preparation of the inner surface of porous silicon by a chemical functionalization process, bovine serum albumin (BSA) molecules, were attached essentially in the upper layer. Simulation study indicates that the proposed sensor works at the refractive index values ranging from 1.3560 to 1.3655. The experimental optical detection of the biomolecules was obtained through the modification of the propagated optical field and losses. The results indicated that the optical attenuation decreases after biomolecules attachment, corresponding to a refractive index change Δnc of the core. This reduction was of about 2 dB/cm and 3 dB/cm for Transverse Electric (TE) and Transverse Magnetic (TM) polarizations respectively. Moreover, at the detection step, the optical field was almost located inside the core layer. This result was in good agreement with the simulated near field profiles

The Effect of Ceramic Wastes on Physical and Mechanical Properties of Eco-Friendly Flowable Sand Concrete

This work aims to study the valorization and recycling of ceramic wastes (wall tiles) as a fine aggregate instead of sand in the manufacturing of flowable sand concrete (FSC). For this, the sand is substituted with the ceramic wastes at different dosages (0, 5, 10, 15, 20, and 25% by volume of the sand). The influence of the ceramic wastes addition on the physical (workability, density) and mechanical (compressive, flexural and elastic modulus) properties of FSC was studied. The results show that the use of ceramic waste as partial replacement of sand contributes to reduce the workability, bulk density and improves the mechanical strengths of FSC according to the use of 25% of wall tiles waste

Management of Cardiovascular Risk among Moroccan Patients with Type 2 Diabetes: A Cross-Sectional Study

Objective: The aim of this study was to estimate the prevalence of cardiovascular disease and investigate cardiovascular risk management among type 2 diabetes (T2D) patients in the city of Meknes. Materials and methods: In a non-interventional cross-sectional study, we enrolled adult outpatients (≥ 18 years old) with T2D from the endocrinology anddiabetology consultation of the Military Hospital of Meknes from June 2021 to January 2022. Informed consent was signed by all participants in the study. Assessment of cardiovascular risk was based on European Society of Cardiology (ESC) Guidelines on cardiovascular disease prevention in clinical practice of 2021. Clinical, biological and therapeutic data were compared between patients with and without cardiovascular disease. Data were analyzed using SPSS version 18 statistical software. Results: One hundred eighty T2D patients were enrolled. The mean age was 59.42 ± 8.72 years. The prevalence of cardiovascular disease was 13.3%. The prescription of statin (p < 0.001), antihypertensive treatment (p < 0.001) and platelet aggregation inhibitors (p < 0.001) was significantly higher in patients with cardiovascular disease. Overall, 5.6% patients were prescribed a blood glucose-lowering agent with demonstrated cardiovascular benefit. This prescription was higher in patients with cardiovascular disease (5 (20.8%) vs. 5 (3.2%); p = 0.004). It was found that7.2% patients had an optimal cardiovascular risk factor management. Conclusions: The prevalence of cardiovascular disease among T2D patients is high in the city of Meknes. Despite an optimal prescription of cardiovascular medications,comprehensive control of cardiovascular risk factors is not achieved in most patients. The use of blood glucose-lowering agents with demonstrated cardiovascular benefit was low but significantly higher among patients with cardiovascular disease