Arts et Métiers ParisTech

About: Arts et Métiers ParisTech is a education organization based out in Paris, France. It is known for research contribution in the topics: Finite element method & Machining. The organization has 3946 authors who have published 6693 publications receiving 142083 citations. The organization is also known as: École nationale supérieure d'arts et métiers & ENSAM.

Effects of a straight oil on friction at the tool-workmaterial interface in machining

Abstract: The quantification of friction coefficient along the tool–workmaterial interface in machining remains an issue in tribology. This paper aims identifying the evolution of friction coefficient for a large range of sliding velocity during the machining of a AISI4140 steel (290 HB) with a TiN coated carbide tool. The influence of a straight oil is investigated compared to a dry sliding situation (dry machining). It has been shown that, in dry machining, friction coefficient decreases with the sliding velocity until reaching a downer limit around 0.2. On the contrary, the presence of a straight oil decreases significantly friction coefficients to a value around 0.1. Additionally, the friction coefficient becomes independent from the sliding velocity. It also been shown that a straight oil is able to penetrate the pin-workmaterial interface even if a very high contact pressure is present (∼3 GPa). The penetration duration is very fast, whereas its evacuation duration is much higher and strongly dependent on sliding speeds.

Thermal analysis by DSC of Phase Change Materials, study of the damage effect

Abstract: This paper deals with an experimental study of Phase Change Materials (PCMs) by DSC and focuses particularly on the influence of PCMs damage on their thermodynamic properties. First, different series of tests were performed on non-damaged PCMs (reference) using different masses and heating rates in order to optimize the choice of the experimental parameters used in DSC test. Accordingly, the specific heats at solid, liquid phases and the latent heats of PCMs were obtained. In addition, a fast approximate approach was suggested for the determination of the heat capacity of PCMs from a direct exploitation of the heat flux curves obtained by scanning PCMs at different heating rates. Finally, damaged PCMs were investigated and their thermal properties (specific heat and phase change enthalpy) were compared to the reference PCMs. It was shown from the obtained results that low heating rates are more suitable for PCMs scanning during DSC measurements in order to ensure a thermodynamic equilibrium within the sample. Furthermore, the results highlighted that damage of PCMs can lead to the loss of their specific heat capacity of about 28% compared to the non-damaged PCMs.

Effects of Mixing Conditions on Pasta Dough Development and Biochemical Changes

Abstract: Mixing of commercial durum wheat semolina with water was performed under different conditions in a Brabender micromixer equipped with pastamaking shafts. Semolina filling of the mixing chamber was 30.4–42.9% (v/v), shaft speed was 10–110 rpm, temperature was 10–40°C, and hydration level was 47–52.5% (db). The blend of water and semolina evolved from individualized hydrated particles (HP) to a dough product (DP) as a function of these conditions. Torque values (T) and the specific mechanical energies (SME) were recorded during mixing as a function of time. Terms from these curves were defined to characterize the mixing process: to (starting time of dough development), td (time to reach the maximum dough consistency), Tm (mean torque value after dough development), and SMEf (total energy applied to the dough during mixing). Transformation of HP into DP and the mixing temperature were the main parameters affecting to, td, Tm, and SMEf. Protein aggregate distribution was measured by size-exclusion HP...