5,982 research outputs found

    Air frame drag balance Patent

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    Device for measuring drag forces in flight test

    Industrial effluent treatment with immersed MBRs: Treatability and cost

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    A comprehensive OPEX analysis for both municipal and industrial wastewaters has been conducted encompassing energy, critical component (membrane) replacement, chemicals consumption, waste disposal and labour. The analysis was preceded by a review of recent data on industrial effluent treatability with reference to published chemical oxygen demand (COD) removal data for four effluent types: food and beverage, textile, petroleum and landfill leachate. Outcomes revealed labour costs to be the most significant of those considered, contributing 50% of the OPEX for a 10,000 m3/day capacity municipal wastewater treatment works. An analysis of the OPEX sensitivity to 12 individual parameters (labour cost, flux, electrical energy cost, membrane life, feed COD, membrane cost, membrane air-scour rate, chemicals cost, waste disposal cost, mixed liquor suspended solids (MLSS) concentration, recirculation ratio, and transmembrane pressure) revealed OPEX to be most sensitive to labour effort and/or costs for all scenarios considered other than a large (100,000 m3/day capacity) works, for which flux and electrical energy costs were found to be slightly more influential. It was concluded that for small- to medium-sized plants cost savings are best made through improving the robustness of plants to limit manual intervention necessitated by unforeseen events, such as electrical/mechanical failure, foaming or sludging. - IWA Publishing 2019.This work was made possible by the support of a National Priorities Research Programme (NPRP) grant from the Qatar National Research Fund (QNRF), grant reference number NPRP8-1115-2-473. The statements made herein are solely the responsibility of the authors

    Detecting periodicity in experimental data using linear modeling techniques

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    Fourier spectral estimates and, to a lesser extent, the autocorrelation function are the primary tools to detect periodicities in experimental data in the physical and biological sciences. We propose a new method which is more reliable than traditional techniques, and is able to make clear identification of periodic behavior when traditional techniques do not. This technique is based on an information theoretic reduction of linear (autoregressive) models so that only the essential features of an autoregressive model are retained. These models we call reduced autoregressive models (RARM). The essential features of reduced autoregressive models include any periodicity present in the data. We provide theoretical and numerical evidence from both experimental and artificial data, to demonstrate that this technique will reliably detect periodicities if and only if they are present in the data. There are strong information theoretic arguments to support the statement that RARM detects periodicities if they are present. Surrogate data techniques are used to ensure the converse. Furthermore, our calculations demonstrate that RARM is more robust, more accurate, and more sensitive, than traditional spectral techniques.Comment: 10 pages (revtex) and 6 figures. To appear in Phys Rev E. Modified styl

    Cold atoms near superconductors: Atomic spin coherence beyond the Johnson noise limit

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    We report on the measurement of atomic spin coherence near the surface of a superconducting niobium wire. As compared to normal conducting metal surfaces, the atomic spin coherence is maintained for time periods beyond the Johnson noise limit. The result provides experimental evidence that magnetic near field noise near the superconductor is strongly suppressed. Such long atomic spin coherence times near superconductors open the way towards the development of coherently coupled cold atom / solid state hybrid quantum systems with potential applications in quantum information processing and precision force sensing.Comment: Major revisions of the text for submission to New Journal of Physics 8 pages, 4 figure

    Ad- and desorption of Rb atoms on a gold nanofilm measured by surface plasmon polaritons

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    Hybrid quantum systems made of cold atoms near nanostructured surfaces are expected to open up new opportunities for the construction of quantum sensors and for quantum information. For the design of such tailored quantum systems the interaction of alkali atoms with dielectric and metallic surfaces is crucial and required to be understood in detail. Here, we present real-time measurements of the adsorption and desorption of Rubidium atoms on gold nanofilms. Surface plasmon polaritons (SPP) are excited at the gold surface and detected in a phase sensitive way. From the temporal change of the SPP phase the Rubidium coverage of the gold film is deduced with a sensitivity of better than 0.3 % of a monolayer. By comparing the experimental data with a Langmuir type adsorption model we obtain the thermal desorption rate and the sticking probability. In addition, also laser-induced desorption is observed and quantified.Comment: 9 pages, 6 figure

    Comparative power demand of mechanical and aeration imposed shear in an immersed membrane bioreactor

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    The power demanded for the application of mechanically-imposed shear on an immersed flat sheet (iFS) membrane bioreactor (MBR) has been compared to that of conventional membrane air scouring. Literature correlations based on the Ostwald model were used to define the rheological characteristics of an MBR sludge. The correlation of specific power demand (, in Watts per m2 membrane area) with shear rate γ in s-1 was developed from first principles through a consideration of the force balance on the system in the case of mechanically-imposed shear. The corresponding aeration imposed shear correlation was interpreted from literature information. The analysis revealed the energy required to impose a shear mechanically through oscillation (or reciprocation) of the membrane to be between 20 and 70% less than that demanded for providing the same shear by conventional aeration of the immersed membrane. The energy saving increases with decreasing shear in accordance with a power demand ratio (aeration:mechanical) of 1400γ-1.4 for a specific sludge rheology. Whilst the absolute value is dependent on the sludge rheology, the aeration:mechanical power demand ratio is determined by the difference in the two exponents in the respective correlations between and γ. Consequently, aeration-imparted shear becomes energetically favoured beyond some threshold shear rate value (∼180 s-1, based on the boundary conditions applied in the current study). The outcomes qualitatively corroborate findings from the limited practical measurement of energy demand in MBRs fitted with reciprocating immersed membranes

    A Synopsis of Melanthiaceae (Liliales) with Focus on Character Evolution in Tribe Melanthieae

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    Melanthiaceae s.l. comprises five tribes: Chionographideae, Heloniadeae, Melanthieae, Parideae, and Xerophylleae—each defined by distinctive autapomorphies. The most morphologically diverse tribe Melanthieae, now with seven genera, had not been subject to rigorous phylogenetic character study prior to the current series of investigations that also include an overview of the family. Data from our publications and studies underway are here assessed and integrated, providing a useful overview of Melanthiaceae, and especially of Melanthieae. The results of parsimony analyses of ITS (nuclear ribosomal) and trnL-F (plastid) DNA sequence data correlate with potentially synapomorphic phenotypic characters for genera of Melanthieae, including habit form, rootstock type, bulb shape, inflorescence structure, indumentum type, tepa! shape, nectary morphology, and ovary position. Sequence data also correlate well with the pattern of variation in chromosome number. The molecular and morphological data support generic recircumscription in Melanthieae and also validate several generalizations concerning character evolution within the tribe, as well as among the tribes of the family

    Low-energy excitations of a linearly Jahn-Teller coupled orbital quintet

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    The low-energy spectra of the single-mode h x (G+H) linear Jahn-Teller model is studied by means of exact diagonalization. Both eigenenergies and photoemission spectral intensities are computed. These spectra are useful to understand the vibronic dynamics of icosahedral clusters with partly filled orbital quintet molecular shells, for example C60 positive ions.Comment: 14 pages revte

    Towards precision medicine for pain: diagnostic biomarkers and repurposed drugs

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    We endeavored to identify objective blood biomarkers for pain, a subjective sensation with a biological basis, using a stepwise discovery, prioritization, validation, and testing in independent cohorts design. We studied psychiatric patients, a high risk group for co-morbid pain disorders and increased perception of pain. For discovery, we used a powerful within-subject longitudinal design. We were successful in identifying blood gene expression biomarkers that were predictive of pain state, and of future emergency department (ED) visits for pain, more so when personalized by gender and diagnosis. MFAP3, which had no prior evidence in the literature for involvement in pain, had the most robust empirical evidence from our discovery and validation steps, and was a strong predictor for pain in the independent cohorts, particularly in females and males with PTSD. Other biomarkers with best overall convergent functional evidence for involvement in pain were GNG7, CNTN1, LY9, CCDC144B, and GBP1. Some of the individual biomarkers identified are targets of existing drugs. Moreover, the biomarker gene expression signatures were used for bioinformatic drug repurposing analyses, yielding leads for possible new drug candidates such as SC-560 (an NSAID), and amoxapine (an antidepressant), as well as natural compounds such as pyridoxine (vitamin B6), cyanocobalamin (vitamin B12), and apigenin (a plant flavonoid). Our work may help mitigate the diagnostic and treatment dilemmas that have contributed to the current opioid epidemic
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