http://dspace.univ-setif.dz:8888/jspui/handle/123456789/1423 2026-04-07T11:08:32Z 2026-04-07T11:08:32Z Guermat, Abdelhak Guessoum, Assia Demagh, Nacer-Eddine Zaboub, Monsef Bouhafs, Zaied http://dspace.univ-setif.dz:8888/jspui/handle/123456789/3089 2019-01-27T10:35:25Z 2019-01-27T00:00:00Z

Titre: Fibre-optic temperature and pressure sensor based on a deformable concave micro-mirror Auteur(s): Guermat, Abdelhak; Guessoum, Assia; Demagh, Nacer-Eddine; Zaboub, Monsef; Bouhafs, Zaied Résumé: This article presents a fibre-optic sensor that measures temperature and pressure. Its operating principle is based on the amplitude modulation caused by the variation in the radius of a concave micro-mirror crafted into the end of an SMF optical fibre. In fact, a micro-cavity engraved into the end of the fibre by selective chemical etching is filled with a PDMS (Polydimethylsiloxane)-type polymer. Due to surface tension, the polymer micro-drop takes on a hemispheric shape characterised by a certain radius. After polymerisation in an oven at 100 °C for one hour, the hemispheric micro-drop is coated with a thin layer of gold using the vacuum evaporation technique. Typically, concave micro-mirrors can be obtained with bend radii of between 10μm and 30μm. Under the action of a temperature gradient or a variation in pressure, the thickness of the PDMS changes and causes a variation in the bend radius of the micro-mirror. As a result, the light intensity guided by the optical fibre and reflected by the micro-mirror is modulated by the variation in its bend radius. In this configuration, the sensor has a thermo-sensitivity of – 0.08dB/°C with a resolution of 0.13 °C in a range of between 20 °C and 100 °C. It also has a pressure sensitivity of 0.11dB/bar between 10 and 20 bars. The measurements are taken by a reflectometer (OTDR). In addition, the experimental results have been validated by theoretical modelling. This sensor is relatively simple to make and can be used in a wide range of applications, in particular biomedical and industrial ones.

2019-01-27T00:00:00Z Boudilmi, A Loucif, K http://dspace.univ-setif.dz:8888/jspui/handle/123456789/3088 2019-01-27T09:49:53Z 2019-01-27T00:00:00Z

Titre: HARDNESS MEASUREMENTS VIA AN ELLIPSOID-SHAPED INDENTER Auteur(s): Boudilmi, A; Loucif, K Résumé: In this theoretical study, we have chosen to use a body of an ellipsoidal geometric form as an indenter, where we determined the mathematical expression of the static hardness as function of the depth and the radii of the area of projected imprint. We used the general formula of the static hardness expressed by the ratio of a force applied perpendicular on the indenter to the resulting area of the imprint; also, we have established the real imprint (cap) of an indenter of revolution ellipsoid form. Finally, geometrical and mathematical approaches have been used to derive the formula of the static hardness expression.

2019-01-27T00:00:00Z Boudilmi, A Loucif, K http://dspace.univ-setif.dz:8888/jspui/handle/123456789/3087 2019-01-27T09:45:14Z 2019-01-27T00:00:00Z

Titre: A Theoretical Study of Indentation with an Oblate Spheroid Shape Auteur(s): Boudilmi, A; Loucif, K Résumé: In this study, firstly we introduced general mathematical concepts related to the geometrical form of ellipse and ellipsoid. Secondly, the hardness was calculated when we used an indenter having a geometrical shape of an oblate spheroid; the mathematical expressions of static hardness were determined as functions of the applied load, the radius or the depth of the imprint area. The general static hardness formula was expressed considering the projected and the real area imprint of the oblate spheroid indenter. Thirdly mathematical assumptions were introduced in order to simplify the mirohardness and nanohardness formulas when we used the real imprint area. Finally we did a comparative study between the oblate spheroid and the spherical indenters.

2019-01-27T00:00:00Z Bensaid, Nasreddine Benbahouche, Saci Roumili, Fouad Sangleboeuf, Jean-Christophe Le Cam, Jean-Benoît Rouxel, Tanguy http://dspace.univ-setif.dz:8888/jspui/handle/123456789/3072 2019-01-20T10:45:24Z 2019-01-20T00:00:00Z

Titre: Influence of the normal load of scratching on cracking and mechanical strength of soda-lime-silica glass Auteur(s): Bensaid, Nasreddine; Benbahouche, Saci; Roumili, Fouad; Sangleboeuf, Jean-Christophe; Le Cam, Jean-Benoît; Rouxel, Tanguy Résumé: The response of glass to a scratch experiment is first reviewed. Then the influence of the applied load on the microcracking pattern, the apparent friction coefficient, and the strength (post scratch test) are studied and discussed for a soda-lime-silica glass (standard window glass composition). As the normal load increases, the depth of the radial crack seems to stabilize at about 100 μm length. Correlatively it is observed that the residual strength of the scratched glass remains at about 40 MPa whatever the scratch load above 0.5 N. Generally, this work contributes theoretically in the understanding of the existing factor controlling scratch in glasses.

2019-01-20T00:00:00Z