Experimental Determination of Thermophysical Properties of Working Fluids for ORC Applications

The design and optimization of Organic Rankine Cycle (ORC) require knowledge concerning the thermophysical properties of the working fluids: pure components or mixtures. These properties are generally calculated by thermodynamic and transport property models (thermodynamic or equation of state or correlations). The parameters of these models are adjusted on accurate experimental data. The main experimental data of interest concern phase equilibrium properties (noncritical and critical data), volumetric properties (density and speed of sound), energetic properties (enthalpy, heat capacity), and transport properties (dynamic viscosity and thermal conductivity). In this chapter, some experimental techniques frequently used to obtain the experimental data are presented. Also, we will present some models frequently used to correlate the data and some results (comparison between experimental data and model predictions)

An improved static–analytic apparatus for vapor–liquid equilibrium (PTxy) measurement using modified in-situ samplers

International audienceAn improved apparatus based on the static-analytic method for reliable vapor-liquid equilibrium (VLE) data measurement is presented in this work. It has been applied to investigate systems containing organic sulfur compounds. New sampling mechanisms were combined with ROLSI TM capillary samplers to achieve on-line sampling for both vapor and liquid phases in a pressure range between 0.1 and 10 bar. Phase samples were directly sent to a gas chromatograph for composition analysis. The equipment was tested against other commonly used experimental methods in this pressure range on the (n-butane + ethanol) and (diethyl sulfide + ethanol) systems. The obtained data were correlated by Wilson model and compared with existing data. The improved apparatus has shown comparable performances to existing methods, while showing some advantages such as complete PTxy phase measurements and less product consumption. After the validation step, additional VLE data for binary systems of interest, (diethyl sulfide + n-butane) and (1-pentanethiol + 1-pentanol), were reported and modeled in this work

A New Static Analytic Apparatus for Complete Determination of Phase Equilibrium Data from Sub-atmospheric Pressures up to 10 bar

International audienceA new static-analytic apparatus equipped two ROLSI TM capillary samplers was presented.The proposed improvements allow ROLSI TM to perform in-situ sampling even at P < P carrier gas. The apparatus has shown comparable performances to existing methods, while showing some advantages. Two binary systems of interest were investigated. New systems are expected to be investigated for various applications in chemical engineering. The liquid sampling mechanism is expected to be used for liquid-liquid equilibrium measurement

Draxin acts as a molecular rheostat of canonical Wnt signaling to control cranial neural crest EMT

Neural crest cells undergo a spatiotemporally regulated epithelial-to-mesenchymal transition (EMT) that proceeds head to tailward to exit from the neural tube. In this study, we show that the secreted molecule Draxin is expressed in a transient rostrocaudal wave that mirrors this emigration pattern, initiating after neural crest specification and being down-regulated just before delamination. Functional experiments reveal that Draxin regulates the timing of cranial neural crest EMT by transiently inhibiting canonical Wnt signaling. Ectopic maintenance of Draxin in the cranial neural tube blocks full EMT; while cells delaminate, they fail to become mesenchymal and migratory. Loss of Draxin results in premature delamination but also in failure to mesenchymalize. These results suggest that a pulse of intermediate Wnt signaling triggers EMT and is necessary for its completion. Taken together, these data show that transient secreted Draxin mediates proper levels of canonical Wnt signaling required to regulate the precise timing of initiation and completion of cranial neural crest EMT

Ets-1 Confers Cranial Features on Neural Crest Delamination

Neural crest cells (NCC) have the particularity to invade the environment where they differentiate after separation from the neuroepithelium. This process, called delamination, is strikingly different between cranial and trunk NCCs. If signalings controlling slow trunk delamination start being deciphered, mechanisms leading to massive and rapid cranial outflow are poorly documented. Here, we show that the chick cranial NCCs delamination is the result of two events: a substantial cell mobilization and an epithelium to mesenchyme transition (EMT). We demonstrate that ets-1, a transcription factor specifically expressed in cranial NCCs, is responsible for the former event by recruiting massively cranial premigratory NCCs independently of the S-phase of the cell cycle and by leading the gathered cells to straddle the basal lamina. However, it does not promote the EMT process alone but can cooperate with snail-2 (previously called slug) to this event. Altogether, these data lead us to propose that ets-1 plays a pivotal role in conferring specific cephalic characteristics on NCC delamination

Utilisation du raisonnement géométrique pour la planification en robotique d'assemblage :

Utilisation du raisonnement géométrique pour la planification de mouvements en robotique. Utilisation de l'intelligence artificielle et de la modélisation géométrique pour la programmation automatique des robots. Cas des mouvements fins correspondants a un assemblag

PleiotRHOpic

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[Coutume. Poitou. 1565]

Sign. *-*8, A-2H5/8. - Lettrine

Vapor Liquid Equilibrium Data for the Furan-Toluene Binary System between 313.02 and 352.99 K

International audienceThe study presents p-T-x-y phase equilibria measurements of an oxygenated compound (furan) and one of its potential solvent of extraction (toluene). The experimental technique of the equipment recently developed is based on a " static analytic " method. Measurements were done at three temperatures (313.02, 333.02 and 352.99 K) and pressures from 13 up to 375 kPa. The experimental data measured were successfully correlated, using a " gamma phi " approach, with the NRTL activity coefficient model

Vapour-liquid equilibrium data for the hydrogen sulphide+n-heptane system at temperatures from 293.25 to about 6.9 Mpa.

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