Effect of Inlet Type on Shear Stress and Mixing in an Annular Photobioreactor Involving a Swirling Decaying Flow

Improvement of mixing can lead to an enhancement of photobioreactors productivity, provided that the adverse effect of shear forces is kept below the fragility‐ threshold of cells. Implementation of a swirling decaying flow induced by a tangential inlet in an annular photobioreactor was investigated. The study focused on a compromise solution between the mixing and the resulting shear stress, and various hydrodynamical characteristics were measured for five types of tangential inlets and three Reynolds number values. Comparison with a pseudo‐axial flow induced by a radial inlet indicates that swirling flows are suitable in the particular application of microalgal cultures.     

Positional small-angle X-ray scattering

Positional small-angle X-ray scattering has been implemented and developed as a new nondestructive technique to study the formation and growth of flaws in polymers. The technique consists of measuring the intensity of scattering at a constant scattering angle while the sample is moved through the incident x-ray beam. Examples of applications of the technique from several different materials are presented.     

New measurement system for on line in core high-energy neutron flux monitoring in materials testing reactor conditions

Flux monitoring is of great interest for experimental studies in material testing reactors. Nowadays, only the thermal neutron flux can be monitored on line, e.g., using fission chambers or self-powered neutron detectors. In the framework of the Joint Instrumentation Laboratory between SCK-CEN and CEA, we have developed a fast neutron detector system (FNDS) capable of measuring on line the local high-energy neutron flux in fission reactor core and reflector locations. FNDS is based on fission chambers measurements in Campbelling mode. The system consists of two detectors, one detector being mainly sensitive to fast neutrons and the other one to thermal neutrons. On line data processing uses the CEA depletion code DARWIN in order to disentangle fast and thermal neutrons components, taking into account the isotopic evolution of the fissile deposit. The first results of FNDS experimental test in the BR2 reactor are presented in this paper. Several fission chambers have been irradiated up to a fluence of about 7 × 10(20) n∕cm(2). A good agreement (less than 10% discrepancy) was observed between FNDS fast flux estimation and reference flux measurement.     

Cyber security threat modeling based on the MITRE Enterprise ATT&CK Matrix

Software and Systems Modeling - Enterprise systems are growing in complexity, and the adoption of cloud and mobile services has greatly increased the attack surface. To proactively address these...     

FRICTION FACTOR IN STATIC MIXER AND DETERMINATION OF GEOMETRIC PARAMETERS OF SMX SULZER MIXERS

Pressure drops were determined in fluid flow through SMX Suizer static mixer of different sizes. In order to investigate a large range of Reynolds number, the experiments were performed with fluids of different viscosities. Pressure drops measurements in static mixer considered as a porous medium, are analysed with a capillary model for the determination of the geometric parameters of static mixers: pore diameter and tortuosity. These parameters allow the expression of pressure drops in terms of friction factor,f_c as a function of pore Reynolds number, Re_pA universal equation is obtained for the friction factor:f_c=16/Re_p+,0.194 which covers both viscous and inertial flow regimes.     

Influence of protein heat treatment on the continuous production of food foams

The influence of WPI heat treatment on the continuous production of food foams was investigated using a model food including xanthan. The temperature of heat treatment was increased up to 90 °C using a plate heat exchanger; a rotor–stator unit was used for aeration purpose. The aim was to determine the interplay between heat-induced protein denaturation and aggregation, and the process parameters of aeration operation: namely, rotation speed, residence time and operating pressure. Microstructure, texture and stability of 200% overrun foams were analysed. Experimental results demonstrated that foam microstructure, namely overrun and bubble size distribution, was governed by the process parameters of aeration and depended only slightly on thermal treatment. Conversely, foam stability was strongly improved by heat treatment. These trends agreed roughly with results obtained in a batch kitchen mixer, but batch methods remained unable to predict quantitatively the behaviours observed in continuous aeration operation.     

Study of Undersaturated C60 Solutions in Cs2 by Small Angle Neutron Scattering

Abstract

We measured precisely, using the Small Angle Neutron Scattering (SANS) technique, the radius of the carbon nuclei shell of the C₆₀ molecule, in spite of its small value. For this purpose, controlled undersaturated solutions of C₆₀ in CS₂, where theC₆₀ molecules are individually distributed, were studied in the room temperature range. Absolute measurements also allowed us to extract from the contrast in scattering length the partial molecular volume of the molecule C₆₀ in solution in CS2.     

An empirical study of the psychodynamics of borderline impulsivity: A preliminary report.

The aim of this article is to position borderline impulsivity, as defined by direct and indirect impulsive self-destructive behaviors, within the framework of Kernberg's (1975, 1976) and Masterson's (1976) object relations models and then to test in an exploratory and empirical manner certain hypotheses emerging from this conceptual analysis. We assessed 29 participants using the Impulse Action Patterns section of the Diagnostic Interview for Borderlines—Revised, measuring direct and indirect self-destructive behaviors; the 11th version of the Barratt Impulsiveness Scale, measuring impulsive personality traits; the Subjective Emotion Questionnaire; and two dimensions of the Social Cognition and Object Relations Scale applied to stories from the Thematic Apperception Test and suspected to be related to borderline impulsivity (i.e., affect–tone of relationship paradigms and capacity for emotional investment in values and moral standards). These two dimensions were significantly associated with, and helped predict, self-destructive behaviors. In turn, self-destructive behaviors were associated with impulsive personality traits. We interpreted these findings using the object relations model to posit certain hypotheses on the psychological mechanisms underlying this relationship and to stimulate future research. Finally, we discuss the importance of using the components of personality structure as conceived in the object relations model to better understand borderline impulsivity. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Numerical investigation of bend and torus flows, part I : effect of swirl motion on flow structure in U-bend

As a preliminary study to flow modeling in torus reactors, simulations are carried out in well-known standard geometries, namely 90° and 180° bends. For the latter, two flow configurations are considered, with and without initial swirl motion so as to approach torus reactor conditions. Efficiency of the commercial CFD code FLUENT is investigated by comparing predicted results with experimental measurements available in the literature for both bended configurations. Different turbulent models and near-wall considerations are considered, including k-ε and high Reynolds-stresses models, with the standard wall-function approach as well as the two-layer zonal model and low-Rek-ε models.After validation of the numerical strategy, a parametric study is made to better understand the interactions between Dean vortices, involved by the bend curvature, and the main rotating motion generated by the swirl motion. Simulations are achieved for various values of the initial swirl intensity applied at the bend entry. Numerical simulations show different flow structures, resulting from the progressive Dean vortices perturbations with the increase of swirl intensity.