11,478 research outputs found

    Air Bubbles Enhance Membrane Cleaning: a Future Perspective

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    Air bubbles generated using a novel micro-bubble generator have displayed a dramatic enhancement in cleaning efficiency when used in conjunction with specially formulated cleaning chemicals. In order to establish the effect of this application on membrane performance, a series of experiments were conducted using both a flat sheet test rig and a small scale pilot plant. Experiments show that the size of the bubbles had a dramatic impact on the effects of cleaning. Air bubbles generated in combination with commodity chemicals are large and produce an inconsistent flow. However, in the presence of specially formulated cleaning chemicals, air bubbles become much smaller and refined (micro-bubbles), creating a pulsating-like action. This eases foulant removal and ultimately restores membrane performance to a greater magnitude. In addition to bubble size, the speed of the feed pump proves to be another important factor. An optimum flow speed and bubble size has been determined to achieve the best possible conditions for enhanced cleaning effects. Cleaning effectiveness was quantified by; flux increase, salt rejection increase, turbidity increase of the cleaning solution and by visual inspection of the membrane. Cleaning with air restores membrane performance to a greater extent than without air. Membranes from several major membrane manufacturers were used in this study to determine membrane compatibility with air. Membranes were then subsequently autopsied at Genesys labs in Madrid to establish the impacts of cleaning and whether the micro-bubbles had caused any damage to the membrane surface. A variety of analytical techniques were used including Scanning Electron Microscopy and Infra-Red Spectroscopy. Autopsy results are discussed in another paper. In this paper, the authors describe the equipment use, experimental methodology and results of cleaning with this novel approach

    Cassini detection of Enceladus' cold water-group plume ionosphere

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    This study reports direct detection by the Cassini plasma spectrometer of freshly-produced water-group ions (O+, OH+, H2O+, H3O+) and heavier water dimer ions (HxO(2))(+) very close to Enceladus where the plasma begins to emerge from the plume. The data were obtained during two close ( 52 and 25 km) flybys of Enceladus in 2008 and are similar to ion data in cometary comas. The ions are observed in detectors looking in the Cassini ram direction exhibiting energies consistent with the Cassini speed, indicative of a nearly stagnant plasma flow in the plume. North of Enceladus the plasma slowing commences about 4 to 6 Enceladus radii away, while south of Enceladus signatures of the plasma interaction with the plume are detected 22 Enceladus radii away. Citation: Tokar, R. L., R. E. Johnson, M. F. Thomsen, R. J. Wilson, D. T. Young, F. J. Crary, A. J. Coates, G. H. Jones, and C. S. Paty ( 2009), Cassini detection of Enceladus' cold water-group plume ionosphere, Geophys. Res. Lett., 36, L13203, doi:10.1029/2009GL038923

    Integrating personality research and animal contest theory: aggressiveness in the green swordtail <i>Xiphophorus helleri</i>

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    &lt;p&gt;Aggression occurs when individuals compete over limiting resources. While theoretical studies have long placed a strong emphasis on context-specificity of aggression, there is increasing recognition that consistent behavioural differences exist among individuals, and that aggressiveness may be an important component of individual personality. Though empirical studies tend to focus on one aspect or the other, we suggest there is merit in modelling both within-and among-individual variation in agonistic behaviour simultaneously. Here, we demonstrate how this can be achieved using multivariate linear mixed effect models. Using data from repeated mirror trials and dyadic interactions of male green swordtails, &lt;i&gt;Xiphophorus helleri&lt;/i&gt;, we show repeatable components of (co)variation in a suite of agonistic behaviour that is broadly consistent with a major axis of variation in aggressiveness. We also show that observed focal behaviour is dependent on opponent effects, which can themselves be repeatable but were more generally found to be context specific. In particular, our models show that within-individual variation in agonistic behaviour is explained, at least in part, by the relative size of a live opponent as predicted by contest theory. Finally, we suggest several additional applications of the multivariate models demonstrated here. These include testing the recently queried functional equivalence of alternative experimental approaches, (e. g., mirror trials, dyadic interaction tests) for assaying individual aggressiveness.&lt;/p&gt

    Contemporary hormone therapy with LHRH agonists for prostate cancer: avoiding osteoporosis and fracture.

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    © 2015 Polish Urological Association. All Rights Reserved.Introduction Prostate cancer is a large clinical burden across Europe. It is, in fact, the most common cancer in males, accounting for more than 92,300 deaths annually throughout the continent. Prostate cancer is androgen-sensitive; thus an androgen deprivation therapy (ADT) is often used for treatment by reducing androgen to castrate levels. Several ADT agents have achieved benefits with effective palliation, but, unfortunately, severe adverse events are frequent. Contemporary ADT (Luteinising Hormone Releasing Hormone agonist - LHRHa injections) can result in side effects that include osteoporosis and fractures, compromising quality of life and survival.  Methods In this review we analysed the associated bone toxicity consequent upon contemporary ADT and based on the literature and our own experience we present future perspectives that seek to mitigate this associated toxicity both by development of novel therapies and by better identification and prediction of fracture risk. Results Preliminary results indicate that parenteral oestrogen can mitigate associated osteoporotic risk and that CT scans could provide a more accurate indicator of overall bone quality and hence fracture risk.  Conclusions As healthcare costs increase globally, cheap and effective alternatives that achieve ADT, but mitigate or avoid such bone toxicities, will be needed. More so, innovative techniques to improve both the measurement and the extent of this toxicity, by assessing bone health and prediction of fracture risk, are also required

    Minimal basilar membrane motion in low-frequency hearing

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    Low-frequency hearing is critically important for speech and music perception, but no mechanical measurements have previously been available from inner ears with intact low-frequency parts. These regions of the cochlea may function in ways different from the extensively studied high-frequency regions, where the sensory outer hair cells produce force that greatly increases the sound-evoked vibrations of the basilar membrane. We used laser interferometry in vitro and optical coherence tomography in vivo to study the low-frequency part of the guinea pig cochlea, and found that sound stimulation caused motion of a minimal portion of the basilar membrane. Outside the region of peak movement, an exponential decline in motion amplitude occurred across the basilar membrane. The moving region had different dependence on stimulus frequency than the vibrations measured near the mechanosensitive stereocilia. This behavior differs substantially from the behavior found in the extensively studied high-frequency regions of the cochlea

    Scaling aerosol assisted chemical vapour deposition: Exploring the relationship between growth rate and film properties

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    Thin films of fluorine doped tin oxide were deposited, by an aerosol assisted chemical vapour deposition route, to study the effect of scaling the growth rate. The effect of precursor concentration on the growth rate of the films and the properties of deposited films were compared. The films were characterised by X-ray diffraction, scanning electron microscopy, UV/vis spectroscopy, X-ray photoelectron spectroscopy and Hall effect measurements. A maximum film growth rate of ca. 100 nm min− 1 was observed, which is significantly faster than previously reported aerosol assisted studies. This method shows the ability of aerosol assisted methods to deliver high growth rates whilst maintaining the ease of doping and control over stoichiometry

    Quantum Gravity in Everyday Life: General Relativity as an Effective Field Theory

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    This article is meant as a summary and introduction to the ideas of effective field theory as applied to gravitational systems. Contents: 1. Introduction 2. Effective Field Theories 3. Low-Energy Quantum Gravity 4. Explicit Quantum Calculations 5. ConclusionsComment: 56 pages, 2 figures, JHEP style, Invited review to appear in Living Reviews of Relativit

    Growth dynamics and the evolution of cooperation in microbial populations

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    Microbes providing public goods are widespread in nature despite running the risk of being exploited by free-riders. However, the precise ecological factors supporting cooperation are still puzzling. Following recent experiments, we consider the role of population growth and the repetitive fragmentation of populations into new colonies mimicking simple microbial life-cycles. Individual-based modeling reveals that demographic fluctuations, which lead to a large variance in the composition of colonies, promote cooperation. Biased by population dynamics these fluctuations result in two qualitatively distinct regimes of robust cooperation under repetitive fragmentation into groups. First, if the level of cooperation exceeds a threshold, cooperators will take over the whole population. Second, cooperators can also emerge from a single mutant leading to a robust coexistence between cooperators and free-riders. We find frequency and size of population bottlenecks, and growth dynamics to be the major ecological factors determining the regimes and thereby the evolutionary pathway towards cooperation.Comment: 26 pages, 6 figure

    Optimized Atmospheric-Pressure Chemical Vapor Deposition Thermochromic VO2 Thin Films for Intelligent Window Applications

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    Monoclinic vanadium(IV) oxide (VO2) has been widely studied for energy-efficient glazing applications because of its thermochromic properties, displaying a large change in transmission of near-IR wavelengths between the hot and cold states. The optimization of the reaction between VCl4 and ethyl acetate via atmospheric-pressure chemical vapor deposition (APCVD) was shown to produce thin films of monoclinic VO2 with excellent thermochromic properties (ΔTsol = 12%). The tailoring of the thermochromic and visible light transmission was shown to be possible by altering the density and morphology of the deposited films. The films were characterized by X-ray diffraction, atomic-force microscopy, scanning electron microscopy, ellipsometry, and UV–vis spectrometry. This article provides useful design rules for the synthesis of high-quality VO2 thin films by APCVD
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