Pipe flow of a dense emulsion: Homogeneous shear‐thinning or shear‐induced migration?

The flow field of a 70% concentrated noncolloidal o/w emulsion in a pipe has been investigated by means of Particle Image Velocimetry in a matched refractive index medium. At steady state and in laminar regime, the shape of axial velocity profiles is not parabolic and exhibits a shear‐thinning behavior of the dense emulsion, with a flow index of 0.5 and a negligible yield stress (less than 1 Pa). However, instead of a square root law, the pressure drop increases linearly with U_m. To explain this apparent inconsistency, two mechanisms of different nature are considered. The first originates from a possible relation between the consistency factor and the drop mean diameter. The second mechanism is shear‐induced migration and leads to the development of a concentration gradient in the pipe cross section. Both mechanisms considered reconcile the experimental data, the apparent local shear‐thinning behavior and the linear evolution of the pressure drop with the flow rate. © 2017 American Institute of Chemical Engineers AIChE J, 2017     

The effect of various dietary factors on the size distribution of lymph fat particles in rat

By means of cellulose acetate electrophoresis and measurement of radioactivity, lipoproteins (d≤1,006) of lymph collected from rats fed a diet containing fats added to labeled fatty acids for 20–24 hr, have been separated into two kinds differing in their size. Fats with different saturated and unsaturated fatty acid content were tested: corn oil, lard, mutton tallow, tripalmitin, corn oil-lard mixture, and randomized palmitic-linoleic triglycerides. Factors studied were: (a) increased amounts of these fats given alone or included in a test meal; (b) added amounts of nutrients (other than fats) in the test meal; (c) adaptation to a diet containing 20% fat for 10 days. The major part of the labeled lymph lipid was always transported by the smaller particles. Size distribution of lymph fat particles was influenced by some of the factors studied. Generally, unsaturated fats produced higher amounts of larger particles.     

The “Conducting Master”: An Interactive,Real-Time Gesture Monitoring System Based on Spatiotemporal Motion Templates

Research in the field of embodied music cognition has shown the importance of coupled processes of body activity (action) and multimodal representations of these actions (perception) in how music is processed. Technologies in the field of human–computer interaction (HCI) provide excellent means to intervene into, and extend, these coupled action-perception processes. In this article this model is applied to a concrete HCI application, called the “Conducting Master.” The application facilitates multiple users to interact in real time with the system in order to explore and learn how musical meter can be articulated into body movements (i.e., meter-mimicking gestures). Techniques are provided to model and automatically recognize these gestures in order to provide multimodal feedback streams back to the users. These techniques are based on template-based methods that allow approaching meter-mimicking gestures explicitly from a spatiotemporal account. To conclude, some concrete setups are presented in which the functionality of the Conducting Master was evaluated.     

Self-ordered particle trains in inertial microchannel flows

Controlling the transport of particles in flowing suspensions at microscale is of interest in numerous contexts such as the development of miniaturized and point-of-care analytical devices (in bioengineering, for foodborne illnesses detection, etc.) and polymer engineering. In square microchannels, neutrally buoyant spherical particles are known to migrate across the flow streamlines and concentrate at specific equilibrium positions located at the channel centerline at low flow inertia and near the four walls along their symmetry planes at moderate Reynolds numbers. Under specific flow and geometrical conditions, the spherical particles are also found to line up in the flow direction and form evenly spaced trains. In order to statistically explore the dynamics of train formation and their dependence on the physical parameters of the suspension flow (particle-to-channel size ratio, Reynolds number and solid volume fraction), experiments have been conducted based on in situ visualizations of the flowing particles by optical microscopy. The trains form only once particles have reached their equilibrium positions (following lateral migration). The percentage of particles in trains and the interparticle distance in a train have been extracted and analyzed. The percentage of particles organized in trains increases with the particle Reynolds number up to a threshold value which depends on the concentration and then decreases for higher values. The average distance between the surfaces of consecutive particles in a train decreases as the particle Reynolds number increases and is independent of the particles size and concentration, if the concentration remains below a threshold value related to the degree of confinement of the suspension flow.     

Material and environmental parameter effects on the leaching of cement pastes: Experiments and modelling

Results already published on the leaching of cement pastes have shown that the kinetics depends sensitively on the material and environment. However and because of the variability of the tested materials and leaching protocols, it is difficult to compare these data and quantify the effect of each parameter. In this paper, a large experimental database on the leaching kinetics of cement pastes is built. Four parameters are investigated: type of cement (portland cement, silica fume cement, slag cement, ternary cement with slag and fly ash); water-to-cement ratio (0.5; 0.4; 0.25), temperature (26 °C; 72 °C; 85 °C) and chemical composition of the leaching solution (pure water, mineralised water, ammonium nitrate solution). Firstly, the database is used to calculate the leaching kinetics of the cementitious materials. Secondly, a simplified model predicting the one-dimensional leaching kinetics for other water-to-cement ratios and temperature up to 85 °C is presented.     

Composition,particle size and role in dietary fat transport of two different lipoproteins of the intestinal lymph

Rat intestinal lymph very low density lipoproteins have been separated by cellulose acetate electrophoresis. After administration of a meal including natural fats and labeled fatty acids, two labeled bands were detected on the electrophoregraphs. Further separations of these two kinds of particles were performed by density gradient zonal centrifugation. The isolated lipoproteins were analyzed for chemical composition and investigated by electron microscopy and electrophoresis. The moving particles had a higher protein and cholesterol content and a smaller diameter than the particles which remained at the origin. It has also been shown that the major part of the labeled lymph lipids were transported by the smaller particles.     

Safety and efficacy of probiotic lactobacilli in promoting growth in post-weaning Swiss mice

Lactobacillus rhamnosus MA27/6B and L. acidophilus MA27/6R are strains used in feed as probiotics. Their safety profiles and growth-stimulating properties were investigated via in vivo studies on young Swiss mice. After repeated administrations of different probiotic preparations in drinking water, safety parameters determined from liver, spleen and total weight remained unchanged. The growth-stimulating properties of viable or dead lactobacilli were studied after supplementation in drinking water. The feed intake (FI), water intake and body weight gain (WG) of the animals were compared to those of control mice. The lactobacilli supplementation of a sub-optimal diet made of barley allow recording of measurable growth performance of mice. It significantly increased WG compared to control groups (P < 0.01), by +28.9% and +31.7% for L. rhamnosus MA27/6B and L. acidophilus MA27/6R, respectively. This WG was correlated with a decrease in the consumption index. The effect of the dose ingested was also investigated: 10(8) lactobacilli CFU/mouse/day produced greater WG than 10(2), 10(4) or 10(6) CFU/mouse/day. No significant differences in growth performance parameters were observed between mice fed with 10(8) cells of viable or nonviable preparations. The mouse assay described could be used as a preliminary criterion when screening candidate probiotics for growth performance properties.     

Daily dietary iron, zinc and copper intake of infants in Belgium

Daily dietary iron (Fe), zinc (Zn) and copper (Cu) intake in healthy toddlers in the Antwerp region of Belgium, aged 2-3 years, have been evaluated by duplicate portion sampling and compared with weighed food and food composition tables. The elemental content was analysed by atomic absorption spectrometry after acid destruction and heating in a microwave oven. We found a discrepancy between the two methods of intake calculation. Since we found that duplicate portion sampling and analysis, although labour-intensive, is the most accurate way of estimating intake, we selected the values obtained by that method to compare with literature data. Mean Fe intake (4.8ǂ.2 mg/day) was low compared with intakes from most other countries, and far below the population reference intake (PRI) for Belgium and the recommended dietary allowance (RDA) value (10 mg/day). For Zn, mean intake (7.5DŽ.6 mg/day) was higher than in most other countries and above the recently revised PRI for Belgium (4 mg/day). The mean intake of Cu (0.7ǂ.2 mg/day) was found to be similar to those found for most other countries, was far above the PRI for this element (0.4 mg/day) and was at the lower end of the RDA range (0.7-1.0 mg/day). The intake of Cu and Zn by the healthy toddler population in the Antwerp region seems to be adequate, while intake of Fe is critically low.