1,892 research outputs found

    Ventilation of double facades

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    This paper deals with the development and thetesting of a simulation algorithm for the temperaturebehaviour and the flow characteristics of doublefaçades. It has been developed in order to obtain atool which enables the energy consultant to makequick design decisions without being required to usefairly complicated CFD tools.In order to determine the degree of accuracy of thealgorithm, a double façade has been monitored undercontrolled conditions and the results have beencompared against the predicted values for severaldesign situations. The resulting inaccuracy in somecases can be traced back to how the flow resistanceof various geometries are modelled. This paper deals with the development and thetesting of a simulation algorithm for the temperaturebehaviour and the flow characteristics of doublefaçades. It has been developed in order to obtain atool which enables the energy consultant to makequick design decisions without being required to usefairly complicated CFD tools.In order to determine the degree of accuracy of thealgorithm, a double façade has been monitored undercontrolled conditions and the results have beencompared against the predicted values for severaldesign situations. The resulting inaccuracy in somecases can be traced back to how the flow resistanceof various geometries are modelled

    Determination of iron sucrose (Venofer) or iron dextran (DexFerrum) removal by hemodialysis: an in-vitro study

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    BACKGROUND: Intravenous iron is typically administered during the hemodialysis (HD) procedure. HD patients may be prescribed high-flux (HF) or high-efficiency (HE) dialysis membranes. The extent of iron sucrose and iron dextran removal by HD using HF or HE membranes and by ultrafiltration rate (UFR) is unknown. METHODS: Two in vitro HD systems were designed and constructed to determine the dialyzabiltiy of iron from a simulated blood system (SBS) containing 100 mg iron sucrose or iron dextran (system A) or 1000 mg iron sucrose (system B). Both in vitro systems utilized a 6-L closed-loop SBS system that was subject to 4 different HD conditions conducted over 4 hours: HE membrane + 0 ml/hr UFR; HE membrane + 500 ml/hr UFR; HF membrane + 0 ml/hr UFR; HF membrane + 500 ml/hr UFR. Blood flow and dialysate flow rates were 500 ml/min and 800 ml/min, respectively. The dialysate compartment was a 192-L open system for system A and a 6-L closed-loop system for system B. Samples from the SBS and dialysate compartments were taken at various time points and iron elimination rate and HD clearance was determined. Iron removal from the SBS > 15% was considered clinically significant. RESULTS: The greatest percentage removal from the SBS was 13.5% and -0.03% utilizing system A and B, respectively. Iron sucrose and iron dextran dialysate concentration was below the lower limits of assay (< 2 ppm) for system A. Dialysate recovery of iron was negligible: 0 – 5.4 mg system A and 5.47 – 23.59 mg for system B. Dialyzer type or UFR did not affect iron removal. CONCLUSION: HF or HE dialysis membranes do not remove clinically significant amounts of iron sucrose or dextran formulations over a 4-hour HD session. This effect remained constant even controlling for UFR up to 500 ml/hour. Therefore, iron sucrose and iron dextran are not dialyzed by HE or HF dialysis membranes irrespective of UFR

    Seed Quality and Planting Rates Affect Oat Yields

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    Study reveals importance of seedling vigor as well as germination in getting high yields of oats. Tests on planting rates suggest two to three bushels per acre when drilled, more than three if broadcast

    Testing Three Measures of Verbal–Visual Frame Interplay in German News Coverage of Refugees and Asylum Seekers

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    Drawing from framing theory, this article operationalizes and tests three ways to measure how verbal and visual modalities interplay in audiovisual messages to produce meaning. The measures include (a) a ratio of verbal to visual frames; (b) an association rules learning (ARL) procedure; and (c) in-depth analysis of the full audiovisual material. As a step toward validating the measures, they were applied to a sample of German television news stories (n = 98) about refugees and asylum seekers. Though the three measures produced varied results, verbal–visual frame redundancy and congruence were consistently more common than mismatches. Measures differed in the level of effort required to implement them, sample sizes they could handle, and the informative value of results. Future studies are advised to combine the ARL procedure with an in-depth analysis

    A Factorization Algorithm for G-Algebras and Applications

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    It has been recently discovered by Bell, Heinle and Levandovskyy that a large class of algebras, including the ubiquitous GG-algebras, are finite factorization domains (FFD for short). Utilizing this result, we contribute an algorithm to find all distinct factorizations of a given element fGf \in \mathcal{G}, where G\mathcal{G} is any GG-algebra, with minor assumptions on the underlying field. Moreover, the property of being an FFD, in combination with the factorization algorithm, enables us to propose an analogous description of the factorized Gr\"obner basis algorithm for GG-algebras. This algorithm is useful for various applications, e.g. in analysis of solution spaces of systems of linear partial functional equations with polynomial coefficients, coming from G\mathcal{G}. Additionally, it is possible to include inequality constraints for ideals in the input

    Simulation of sand particle transport by coupled CFD-DEM: first investigations

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    The continuum based Euler-Euler approach represents the main field of application for the simulation of sediment transport processes. Herein, the decisive phases of free water and soil are modelled by interpenetrating continua. Although mixing of the phases is possible, the multi-component character of the soil phase, as a mixture of solid grains and pore water, is neglected. Hence, a coupling between the free water and the pore water remains unnoticed as well. However, this coupling represents an important factor for determining the current state of the soil boundary near the transition zone. Due to water level changes caused by ship induced bow and stern waves, excess pore water pressure can occur in the upper soil layers. As a result, fluidisation effects can be initiated, which reduce the erosion resistance. To consider these fluidisation effects, the soil has to be treated as a mixture of dispersed grain particles and pore water by a Lagrange-Euler approach. The coupling of the Discrete Element Method (DEM) and the Computational Fluid Dynamics (CFD) approach offers this possibility. Thereby, the DEM is used for modelling the dispersed particles of the Lagrangian regime, while the CFD method models the continuum Euler-phase of the water. This paper introduces the coupled CFD-DEM method for simulating sand particle transport at the boundary layer transition zone. The model investigations and first results of simulations regarding the initiation of motion are presented

    Cascading the use of Web 2.0 technology in secondary schools in the United Kingdom: identifying the barriers beyond pre-service training

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    This paper reports on research that took place at Nottingham Trent University and Sheffield Hallam University, United Kingdom, over two years. The research focuses on the use of Web 2.0 technology, specifically web logs, with pre-service teachers, both during their university programme and the first year of teaching as full-time newly qualified teachers (NQTs). The purpose of this research was to add a developing body of knowledge by identifying whether technology used by pre-service teachers during their training course can be cascaded into their practice once qualified. Key findings identify a number of enablers and barriers to cascading technology in the classroom; these include curriculum time, pupil skills and support. The research concludes that early professional support and development should be on-going and assumptions about new teachers as champions of cascading innovative use of Web 2 technologies into their practice as NQTs may be over optimisti

    Climate informed engineering: An essential pillar of industry 4.0 transformation

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    Breakthroughs in computing have led to development of new generations of Earth Systems Models providing detailed information on how our planet may locally respond to the ongoing global warming. Access to such climate information systems presents an unprecedented opportunity for engineers to make tangible contributions to climate adaptation through integration of climate information in their products, designs, and services. We introduce the concept of “Climate Informed Engineering” (CIE) as an emerging interdisciplinary field integrating climatic considerations in engineering products and services. The concept behind CIE is to enable engineers to build infrastructure, devices, sensors or develop new materials and processes that are informed by climate and climate change information. We believe CIE will be an increasingly important dimension of Engineering Science resonating with engineers and scientists with different backgrounds

    Membrane Protein Properties Revealed through Data-Rich Electrostatics Calculations.

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    The electrostatic properties of membrane proteins often reveal many of their key biophysical characteristics, such as ion channel selectivity and the stability of charged membrane-spanning segments. The Poisson-Boltzmann (PB) equation is the gold standard for calculating protein electrostatics, and the software APBSmem enables the solution of the PB equation in the presence of a membrane. Here, we describe significant advances to APBSmem, including full automation of system setup, per-residue energy decomposition, incorporation of PDB2PQR, calculation of membrane-induced pKa shifts, calculation of non-polar energies, and command-line scripting for large-scale calculations. We highlight these new features with calculations carried out on a number of membrane proteins, including the recently solved structure of the ion channel TRPV1 and a large survey of 1,614 membrane proteins of known structure. This survey provides a comprehensive list of residues with large electrostatic penalties for being embedded in the membrane, potentially revealing interesting functional information
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