Packaging of yield stress fluids: Flow patterns

The packaging or filling of a container with a non‐Newtonian fluid without quality failures is a current issue encountered at the final step of industrial product processes. In this work, the container filling of viscoplastic fluids is studied using an experimental laboratory plant able to reproduce the industrial transitory packaging conditions. First, a Newtonian validation was conducted to compare and to confirm our setup results with available literature data. Second five flow patterns including dripping, jet buckling, mounding, planar filling, and air entrainment were observed and characterized for the viscoplastic container filling. Most of them present different types of instabilities during the filling, except the planar filling, which seems to be ideal according to industrial specifications. A flow pattern distribution depending on relevant dimensionless numbers was developed. Finally, flow pattern transition criteria are determined highlighting the influence of rheological and process parameters on container filling. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1117–1126, 2018     

Imprinting of founders' entrepreneurial motivations on enterprises' practices and processes: The context of creative industries

This paper explores the imprinting of entrepreneurs' motivations on the practices and processes of enterprises. We investigate the question in the context of creative industries (CIs) as an extreme case of entrepreneurial motivations (EMs) prevalence. We analyse the EM of 14 founders of design consultancies. Three EMs emerge: self‐fulfilment, freedom and financial motivation. The qualitative analysis reveals that the founders' EMs at the time of a venture's founding has a lasting impact on the characteristics of the venture (name, processes formalization, decision‐making processes, performance measures and growth strategies). Specifically, founders driven by self‐fulfilment tend to build ventures named after them. In these ventures, processes are informal, decision‐making is centralized, performance measures are based on personal satisfaction and recognition and enterprise growth is restrained. Founders who seek freedom tend to run enterprises with semiformal processes, semicentralized decision‐making, a client satisfaction focus, and slow growth strategies. In contrast, founders with financial motivations tend to create enterprises with formal processes, decentralized decision‐making, financial performance metrics and growth ambitions. By focusing on EM and adopting a holistic approach beyond some characteristics of the venture, we complement the imprinting literature.     

Enhanced Collective Magnetic Properties Induced by the Controlled Assembly of Iron Oxide Nanoparticles in Chains

1D assemblies of magnetic nanoparticles are of great potential for designing novel nanostructured materials with enhanced collective magnetic properties. In that challenging context, a new assembly strategy is presented to prepare chains of magnetic nanoparticles that are well‐defined in structure and in spatial arrangement. The 1D assembly of iron oxide nanoparticles onto a substrate is controlled using “click” chemistry under an external magnetic field. Co‐aligned single nanoparticle chains separated by regular distances can be obtained by this strategy. The intrinsic high uniaxial anisotropy results in a strong enhancement of magnetic collective properties in comparison to 2D monolayers or isolated nanoparticles. In contrast to the intensively studied bundle chains of nanoparticles, the finely tuned chain structure reported here allows evidencing a first order intrachain dipolar interaction and a second order interchain magnetic coupling. This study offers new insights into the collective magnetic properties of highly anisotropic particulate assemblies which have been investigated by combining superconducting quantum interference device magnetometry, magnetic force microscopy, and ferromagnetic resonance.     

The Stroop and Reverse Stroop Effects as Measured by an Interactive Tabletop

An interactive tabletop equipped with RFID technology implemented the Stroop and reverse-Stroop tasks. Participants moved a tangible object into one of four displayed virtual zones, which were identified either by a color border or the name of a color written in black. The correct target zone corresponded either to the color (Stroop) or meaning (reverse Stroop) of a word displayed in congruent or incongruent colored LED lights (e.g., “YELLOW” displayed in yellow or red, respectively). Participants took more time to place the object in a zone, made more errors, and found the task more difficult when the word was lit with an incongruent than congruent color. This interference was influenced by both the types of task and response zone in a way that fits with a dual step processing account. Results also showed that the outcomes of the conflicting information streams might be judged as fun.     

Differential Sensitivity of Mosquito Taxa to Vegetable Tannins

The sensitivity of larval Culicidae to vegetable tannins was investigated in different taxa representative of the fauna from alpine hydrosystems (Aedes rusticus, Culex pipiens) and foreign noxious fauna (Aedes aegypti, A. albopictus). Bioassays reveal that tannic acid at concentrations of 0.1–6 mM is significantly more toxic for C. pipiens than for Aedes taxa, and A. aegypti is more sensitive than A. albopictus and A. rusticus. Comparison of the rank order of sensitivity among taxa with the associated levels of cytochrome P-450, esterase, and glutathione-S-transferase activities suggests that cytochrome P-450 and esterases may be involved in the detoxification of tannins. A possible involvement of these detoxifying enzymes is also revealed in vivo by the synergistic effects of S,S,S-tributyl phosphorotrithioate (esterase inhibitor) and piperonyl butoxide (P-450 inhibitor). The differential sensitivity to tannins among taxa is discussed in terms of ecological implications within mosquito communities from alpine hydrosystems, where the acquisition of tannins–detoxifying enzymatic systems may be considered as a key innovation.     

Design optimization and optimal control for hybrid vehicles

In the context of growing environmental concerns, hybrid-electric vehicles appear to be one of the most promising technologies for reducing fuel consumption and pollutant emissions. This paper presents a parametric study focused on variations of the size of the powertrain components, and optimization of the power split between the engine and electric motor with respect to fuel consumption. To take into account the ability of the engine to be turned off, and the energy consumed to start the engine, we consider a second state to represent the engine: this state permits to obtain a more realistic engine model than it is usually done. Results are obtained for a prescribed vehicle cycle thanks to a dynamic programming algorithm based on a reduced model, and furnish the optimal power repartition at each time step regarding fuel consumption under constraints on the battery state of charge, and may then be used to determine the best components of a given powertrain. To control the energy sources in real driving conditions, when the future is unknown, a real-time control strategy is used: the Equivalent Consumption Minimization Strategy (ECMS). In this strategy, the battery is being considered as an auxiliary reversible fuel reservoir, using a scaling parameter which can be deduced from dynamic programming results. Offline optimization results and ECMS are compared for a realistic hybrid vehicle application.     

Noradrenergic neuromodulation in the olfactory bulb modulates odor habituation and spontaneous discrimination.

Noradrenergic projections from the locus coeruleus (LC) project to the olfactory bulb (OB), a cortical structure implicated in odor learning and perceptual differentiation among similar odorants. The authors tested the role of OB noradrenaline (NA) in short-term olfactory memory using an animal model of LC degeneration coupled with intrabulbar infusions of NA. Specifically, the authors lesioned cortical noradrenergic fibers in mice with the noradrenergic neurotoxin N-Ethyl-N-(2-chloroethyl)-2-bromobenzylamine hydrochloride (DSP4) and measured the effects on an olfactory habituation/spontaneous discrimination task. DSP4-treated mice failed to habituate to repeated odor presentations, indicating that they could not remember odors over the 5-min intertrial interval. The authors then infused NA bilaterally into the OBs of both DSP4-treated and nonlesioned control animals at two concentrations (10-3M and 10-5M, 2 μl/side). In DSP4-treated animals, NA administration at either concentration restored normal habituation and spontaneous discrimination performance, indicating that noradrenergic neuromodulation mediates these aspects of perceptual learning and that its efficacy does not require activity-dependent local regulation of NA release. Functional OB learning mechanisms may be necessary for normal odor recognition and differentiation among physically similar odorants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

PV processing: Improved PV-cell scribing using water jet guided laser

With the advantages provided by the use of water, water jet guided laser technology overcomes the drawbacks of conventional dry lasers. Scribing of silicon PV-cells is achieved at high speeds (up to 300 mm/s for a grooving that is 30 microns deep), with a level of cleanliness that cannot be attained by conventional dry lasers. There is no chipping due to mechanical stress, which may occur with abrasive saws, and any cutting design can be achieved. The water jet guided laser also works with wafers that are not completely flat, which is often the case with solar cells. To sum up, the Laser-Microjet is a well-fitted tool for fast and clean PV-cell processing.     

Using item response theory to study the convergent and discriminant validity of three questionnaires measuring cigarette dependence.

To determine whether the Cigarette Dependence Scale, the Fagerstr?m Test for Nicotine Dependence, and the Nicotine Dependence Syndrome Scale (NDSS) reliably and correctly assessed both weakly and severely dependent individuals, the authors collected data via Internet from 2,435 current smokers, from 2004 to 2007. They used a 2-parameter item response model to determine the difficulty and discrimination of each question and used correlations between latent scores to assess convergent and discriminant validity. The reliability of all scales was close to or exceeded .70. Both the Cigarette Dependence Scale and the Fagerstr?m Test for Nicotine Dependence had 1 misfitting item. Each NDSS scale had at least 2 misfitting items. The information curve of each of the questionnaires peaked between -2 and 2 and was low at both extremes. All questionnaires had adequate reliability and were more informative for a medium level of the underlying cigarette dependence continuum than for both extremes of this continuum. The correlations between latent scores indicated good convergent validity between questionnaires and low discriminant validity between NDSS subscales, except for Tolerance. This result suggests that nicotine dependence may not be composed of 5 dimensions but may be unidimensional and distinct from reduced sensitivity to the effects of smoking (Tolerance). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Outward electron transfer by Saccharomyces cerevisiae monitored with a bi‐cathodic microbial fuel cell‐type activity sensor

A Janus head‐like bi‐cathodic microbial fuel cell was constructed to monitor the electron transfer from Saccharomyces cerevisiae to a woven carbon anode. The experiments were conducted during an ethanol cultivation of 170 g/l glucose in the presence and absence of yeast‐peptone medium. First, using a basic fuel‐cell type activity sensor, it was shown that yeast‐peptone medium contains electroactive compounds. For this purpose, 1% solutions of soy peptone and yeast extract were subjected to oxidative conditions, using a microbial fuel cell set‐up corresponding to a typical galvanic cell, consisting of culture medium in the anodic half‐cell and 0.5 M K₃Fe(CN)₆ in the cathodic half‐cell. Second, using a bi‐cathodic microbial fuel cell, it was shown that electrons were transferred from yeast cells to the carbon anode. The participation of electroactive compounds in the electron transport was separated as background current. This result was verified by applying medium‐free conditions, where only glucose was fed, confirming that electrons are transferred from yeast cells to the woven carbon anode. Knowledge about the electron transfer through the cell membrane is of importance in amperometric online monitoring of yeast fermentations and for electricity production with microbial fuel cells. Copyright © 2009 John Wiley & Sons, Ltd.