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Rombaut N.,Compiegne University of Technology | Rombaut N.,French National Center for Scientific Research | Savoire R.,Compiegne University of Technology | Savoire R.,French National Center for Scientific Research | And 4 more authors.
Industrial Crops and Products | Year: 2015

Grape seed oil being industrially obtained by solvent extraction, in this study we investigate oil extraction from grape seeds by cold screw pressing, as an alternative extraction process.Effect of raw material and process parameters were evaluated using a 12 experiments Taguchi experimental design. Variables were (1) type of grape seeds, (2) preheating temperature (90 and 120. °C), (3) screw rotation speed (40 and 70. rpm) and (4) die diameter (10 and 15. mm). The type of grape seed was the most influencing parameter on the studied responses. Screw rotation speed and die diameter only affected the oil yield. Maximum oil yield was observed for type 1 grape seeds (64.3%, o/o). Total oil polyphenol content was also maximal for type 1 seeds with up to 121. mg. GAE/kg of oil. Maximum oil yield was 57.3% and 58.8% (o/o) for type 2 and type 3 grape seed respectively and total polyphenol oil content was below 90. mg. GAE/kg for these two types of seeds. Additional experiments were carried out on type 1 seeds to enhance oil yield and oil polyphenol content. Maximal oil yield achieved was 73% (o/o) and total oil polyphenol content was increased up to 26% (153. mg/kg of oil) on the maximum yield obtained with Taguchi design. © 2014 Elsevier B.V.

Durin A.,MINES ParisTech | De Micheli P.,MINES ParisTech | Ville J.,POLYTECHS SA | Ville J.,CNRS Laboratory of Materials Engineering of Brittany | And 3 more authors.
Composites Part A: Applied Science and Manufacturing | Year: 2013

Limiting fibre breakage during composite processing is a crucial issue. The purpose of this paper is to predict the evolution of the fibre-length distribution along a twin-screw extruder. This approach relies on using a fragmentation matrix to describe changes in the fibre-length distribution. The flow parameters in the screw elements are obtained using the simulation software Ludovic®. Evolution of an initial fibre-length distribution for several processing conditions was computed and the results were compared with experimental values. The computation gives satisfying results, even though more comparisons with experiments would be necessary. © 2013 Elsevier Ltd. All rights reserved.

Abou Nader C.,Saint - Joseph University | Abou Nader C.,Institut Universitaire de France | Pellen F.,Institut Universitaire de France | Roquefort P.,CNRS Laboratory of Materials Engineering of Brittany | And 4 more authors.
Optics Letters | Year: 2016

The noninvasive detection of a material's viscoelasticity is of great importance in the medical field. In fact, certain diseases cause changes in tissue structure and biological fluid viscosity; tracking those changes allows for detection of these diseases. Rheological measurements are also imperative in the industrial field, where it is necessary to characterize a material's viscoelasticity for manufacturing purposes. In this Letter, we present a noncontact, noninvasive, and low cost method for determining low viscosity values and variations in fluids. Laser speckle and viscometric measurements are performed on test samples having low scattering coefficients and low viscosities. The speckle spatial analysis proved to be as accurate as the speckle temporal correlation method reported in previous studies. Very low viscosities of the order of 1 mPa.s were retrieved for the first time using speckle images with either a frame rate of 1950 fps or a single acquired image. © 2016 Optical Society of America.

Brest J.S.,CNRS Laboratory of Materials Engineering of Brittany | Brest J.S.,Higher Institute of Aeronautics and Space | Keryvin V.,CNRS Laboratory of Materials Engineering of Brittany | Longere P.,Higher Institute of Aeronautics and Space | Yokoyama Y.,Tohoku University
Journal of Alloys and Compounds | Year: 2014

Multiaxial and heterogeneous mechanical experiments, by means of the diametral compression test (Brazilian test), were carried out on Zr-based Bulk Metallic Glass. Attention was notably focused on obtaining the displacement field in the area of interest (large strains) employing a Digital Image Correlation device, in addition to the measurement of the usual global load-displacement curve. In order to reproduce the behaviour of the BMG at stake, several constitutive equations were considered with growing complexity: von Mises, Drucker-Prager (pressure dependence), free volume based model as well as a viscoplastic Coulomb-Mohr type model. The two latter were implemented as user-material in a Finite Element computation code. The results of these investigations including experiments and computational simulations are discussed. © 2012 Elsevier B.V. All rights reserved.

Helbert G.,IFSTTAR | Saint-Sulpice L.,CNRS Brest Laboratory of Mechanics and Systems Laboratory | Arbab Chirani S.,CNRS Brest Laboratory of Mechanics and Systems Laboratory | Dieng L.,IFSTTAR | And 3 more authors.
Mechanics of Materials | Year: 2014

NiTi shape memory alloys (SMAs) wires exhibit R-phase frequently. This intermediate phase has interesting properties under cyclic loadings and fatigue. These wires have a good potential in civil engineering applications for their damping capacity. In accordance with these applications, in this study, a complete characterisation of NiTi wires is proposed. First the pseudo phase diagram concerning R-phase and its existence comparing to austenite or to martensite is obtained by realising tensile tests at different temperatures and strain amplitudes. Then, the cyclic behaviour under tension at various amplitudes is studied. Based on these loadings, the significant observations are: a small residual strain, the decrease of transformation yield stresses and the evolution of the hysteresis size with the number of cycles. To consider the real use conditions, the effect of strain rate has been studied at two temperatures. The obtained results show that, due to thermo-mechanical coupling, the mechanical behaviour is affected by the evolution of strain rate. Eventually, the damping effect of the studied wires has been evaluated. All the obtained results confirm the potential use of NiTi wires exhibiting R-phase in civil engineering applications. They also constitute an interesting reference for models development describing R-phase occurrence and ease their identification and validation procedures. © 2014 Elsevier Ltd. All rights reserved.

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