45 research outputs found
Nano-micro structured superhydrophobic zinc coating on steel for prevention of corrosion and ice adhesion
Thin films of zinc have been deposited on steel substrates by electrodeposition process and further functionalized with ultra-thin films of commercial silicone rubber, in order to obtain superhydrophobic properties. Morphological feature, by scanning electron microscope (SEM), shows that the electrodeposited zinc films are composed of micro-nano rough patterns. Furthermore, chemical compositions of these films have been analyzed by X-ray diffraction (XRD) and infra-red (IRRAS). An optimum electrodeposition condition, based on electrical potential and deposition time, has been obtained which provides superhydrophobic properties with a water contact angle of 155 ± 1°. The corrosion resistance properties, in artificial seawater, of the superhydrophobic zinc coated steel are found to be superior to bare steel. Similarly, the measured ice adhesion strength on superhydrophobic surfaces, using the centrifugal adhesion test (CAT), is found to be 6.3 times lower as compared to bare steel. This coating has promising applications in offshore environment, to mitigate corrosion and reduce ice adhesion
Self-administered multi-level pregnancy tests in simplified follow-up of medical abortion in Tunisia
MOLLUSCICIDAL AND LARVICIDAL ACTIVITIES OF Atriplex inflata AERIAL PARTS AGAINST THE MOLLUSK Galba truncatula, INTERMEDIATE HOST OF Fasciola hepatica
Fasciolosis is a widespread parasitosis of farm live-stock in many developing countries. For this reason, it is necessary to search for new substances against parasitic diseases caused by flukes. Indeed, a wide variety of terrestrial plants have been subjected to chemical and pharmacological screening in order to discover their potential for human medicinal use. The molluscicidal and larvicidal activities of Atriplex inflata were tested on Galba truncatula and Fasciola hepatica larval stages infecting this snail in Tunisia. Phytochemical tests were conducted on extracts in order to establish a meaningful relationship with molluscicidal and larvicidal activities. The molluscicidal activity was evaluated by subjecting snails to sample aqueous solutions. Accordingly, hexane, ethyl acetate, methanol and methanol-water (8:2, v-v) were used as extraction solvents. As a result, hexane and ethyl acetate extracts showed potent activity, according to the World Health Organization, giving LC50 = 7.59 mg/L and 6.69 mg/L for hexane extracts of leaves and fruits, respectively. Ethyl acetate extracts gave LC50 = 5.90 mg/L and 7.32 mg/L for leaves and fruits, successively. Molluscicidal activities of powders were less potent on snails, but active according to the World Health Organization. Hexane and ethyl acetate extracts from leaves and fruits gave potent larvicidal activities with a delay rate exceeding 45.50% (45.50- 98.92%). Phytochemical tests showed that these activities may be attributed to the presence of triterpenoids and/or sterols
Étude d´un matériau routier composé de laitier de haut fourneau et de sable de dune
L’objectif de notre travail de recherche est de combiner le sable de dune au laitier de haut fourneau activé
par la chaux afin de les utiliser en technique routière au moyen de mélange du sable laitier.
Il sera question de formuler le sable laitier afin de voir l’influence de différents pourcentages de laitier
granulé, sur la portance et les caractéristiques mécaniques d’un sable laitier dans le but de déterminer la
teneur optimale en laitier permettant d’obtenir des indices portant et des résistances à la compression
simples permettant d’utiliser le mélange obtenu comme couches d’une chaussée routière semi rigide.
Les résultats obtenus, sur des éprouvettes à 0, 7, 28, 60, 90 et 180 jours, montrent que l’incorporation
progressive du laitier activé par une chaux entraîne une augmentation de l’indice portant immédiat, de la
résistance à la compression simple et de la résistance à la tractio
Curing and Post-curing influence on positive electrostatic charges deposited on epoxy/silica composites
6th International Conference on Electric charges in non-conductive Materials (CSC'6) Tours (France
Effect of annealing on the electrical properties of SrTiO3 thin films produced by ion beam sputtering
International audienc
Effect of the ce content on a nuclear waste glassy matrix in the system SiO2-Al2O3-CaO-MgO-ZrO2-TiO2, synthesized at a low melting temperature
Aluminosilicated glasses containing Zr and Ti metals have satisfactory properties, and may be suitable as nuclear glasses, dedicated for storage of radioactive waste solutions. This study summarizes the synthesis of a glassy matrix in the system: SiO2-Al2O3-CaO-MgO-ZrO2-TiO2. Ce element was added as an actinide surrogate. The effect of Ce addition on the glass structure is investigated, for Ce contents ranging between 0 and 15 wt.%. For the whole of glasses, a double melting at 1,350°C during 5 h gave monophasic homogeneous glasses. Both X-ray diffraction and scanning electron microscopy analyses reveal a pure amorphous structure. Most of the basic properties increase with the glass Ce content, the Archimedes density from 2.827 to 3.049 g/cm3, and Vickers indentations from 680 to 862 HV. Oxygen molar volumes are not affected by the glasses Ce contents. The differential thermal analysis show that the glass transformation temperature decreases with the Ce content, and with the heavy elements content. The optical absorption spectroscopy study shows that the Nd cations environment is not altered by the glasses Ce concentration. A preliminary corrosion test leads to low dissolutions of Si, Ca and Zr, estimated by ICP analyses to few ppms. Out coming investigations are in course for further glasses network characterization
Mammographic mass classification according to Bi‐RADS lexicon
The goal of this study is to propose a computer‐aided diagnosis system to differentiate between four breast imaging reporting and data system (Bi‐RADS) classes in digitised mammograms. This system is inspired by the approach of the doctor during the radiologic examination as it was agreed in BI‐RADS, where masses are described by their form, their boundary and their density. The segmentation of masses in the authors’ approach is manual because it is supposed that the detection is already made. When the segmented region is available, the features extraction process can be carried out. 22 visual characteristics are automatically computed from shape, edge and textural properties; only one human feature is used in this study, which is the patient's age. Classification is finally done using a multi‐layer perceptron according to two separate schemes; the first one consists of classify masses to distinguish between the four BI‐RADS classes (2, 3, 4 and 5). In the second one the authors classify abnormalities on two classes (benign and malign). The proposed approach has been evaluated on 480 mammographic masses extracted from the digital database for screening mammography, and the obtained results are encouraging