3,104 research outputs found

    The Balance Between in the Cleaning of Milk Fouling Deposits

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    Deposits formed on the surface of heat treatment equipment in the dairy industry compromise product quality and process efficiency. Frequent cleaning is needed to ensure consumer safety and optimal process operation. Cleaning solutions generally have a high environmental impact; the need is to minimize their use. We have studied the physics and chemistry of cleaning at two length scales of measurement: (i) the effect of cleaning chemical and water on deposits within a plate heat exchanger (PHE), and (ii) the effect of process variables on small fouled disks. The chemical nature of cleaning of dairy deposits is shown clearly by the effect of using pulses of water within a PHE cleaning cycle: cleaning stops for proteins, in contrast to the cleaning of starch pastes from surfaces. Different modes of cleaning can be identified from cleaning of the disks, and effects of physics and chemistry can be separated to some extent

    Probing the Density in the Galactic Center Region: Wind-Blown Bubbles and High-Energy Proton Constraints

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    Recent observations of the Galactic center in high-energy gamma-rays (above 0.1TeV) have opened up new ways to study this region, from understanding the emission source of these high-energy photons to constraining the environment in which they are formed. We present a revised theoretical density model of the inner 5pc surrounding Sgr A* based on the fact that the underlying structure of this region is dominated by the winds from the Wolf-Rayet stars orbiting Sgr A*. An ideal probe and application of this density structure is this high energy gamma-ray emission. We assume a proton-scattering model for the production of these gamma-rays and then determine first whether such a model is consistent with the observations and second whether we can use these observations to further constrain the density distribution in the Galactic center.Comment: 36 pages including 17 figures, submitted to ApJ, comments welcom

    Understanding students’ instrumental goals, motivation deficits and achievement: Through the Lens of a Latent Profile Analysis

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    Building on the future oriented and regulated nature of instrumental goals, Lens and colleagues developed a 2 (proximal-distal) x 2 (internal-external) motivational framework. The current study aimed to test this framework from a person-centred perspective, while equally taking into account students’ lack of motivation as to extend the empirical and theoretical borders of the model. Latent Profile Analyses were used to test the viability of two to five motivational profiles among Japanese second-year students (N = 781). A solution with three latent subgroups fitted the sample best, explaining 6% to 62% of the variance in the measured variables. The profiles were labelled “low future oriented motivational profile”, “average motivated profile”, and “highly motivated profile”. The highly motivated subgroup reported the most adaptive pattern of motivation and highest levels of deep level learning, while few differences were found for surface learning and GPA. Theoretical and practical implications are discussed.published_or_final_versio
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