1,002 research outputs found

    An experimental documentation of a separated trailing-edge flow at a transonic Mach number

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    A detailed experiment on the separated flow field at a sharp trailing edge is described and documented. The separated flow is a result of sustained adverse pressure gradients. The experiment was conducted using an elongated airfoil-like model at a transonic Mach number and at a high Reynolds number of practical interest. Measurements made include surface pressures and detailed mean and turbulence flow quantities in the region just upstream of separation to downstream into the near-wake, following wake closure. The data obtained are presented mostly in tabular form. These data are of sufficient quality and detail to be useful as a test case for evaluating turbulence models and calculation methods

    An experimental documentation of trailing-edge flows at high Reynolds number

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    Experiments documenting attached trailing-edge and near-wake flows at high Reynolds numbers are described. A long, airfoil-like model was tested at subsonic and low transonic Mach numbers, and both symmetrical and asymmetrical flows with pressure gradients upstream of the trailing edge were investigated. Model surface pressures and detailed mean and turbulence flow qualities were measured in the vicinity of the trailing edge and in the near-wake. The data obtained are of sufficient quality and detail to be useful as test cases in assessing turbulence models and calculation methods

    ESTIMATING CORN YIELD RESPONSE MODELS TO PREDICT IMPACTS OF CLIMATE CHANGE

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    Projections of the impacts of climate change on agriculture require flexible and accurate yield response models. Typically, estimated yield response models have used fixed calendar intervals to measure weather variables and omitted observations on solar radiation, an essential determinant of crop yield. A corn yield response model for Illinois crop reporting districts is estimated using field data. Weather variables are time to crop growth stages to allow use of the model if climate change shifts dates of the crop growing season. Solar radiation is included. Results show this model is superior to conventionally specified models in explaining yield variation in Illinois corn.Crop Production/Industries,

    Unified Theory of Acceptance and Use of Technology: A Synthesis and the Road Ahead

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    The unified theory of acceptance and use of technology (UTAUT) is a little over a decade old and has been used extensively in information systems (IS) and other fields, as the large number of citations to the original paper that introduced the theory evidences. In this paper, we review and synthesize the IS literature on UTAUT from September 2003 until December 2014, perform a theoretical analysis of UTAUT and its extensions, and chart an agenda for research going forward. Based on Weber’s (2012) framework of theory evaluation, we examined UTAUT and its extensions along two sets of quality dimensions; namely, the parts of a theory and the theory as a whole. While our review identifies many merits to UTAUT, we also found that the progress related to this theory has hampered further theoretical development in research into technology acceptance and use. To chart an agenda for research that will enable significant future work, we analyze the theoretical contributions of UTAUT using Whetten’s (2009) notion of cross-context theorizing. Our analysis reveals several limitations that lead us to propose a multi-level framework that can serve as the theoretical foundation for future research. Specifically, this framework integrates the notion of research context and cross-context theorizing with the theory evaluation framework to: 1) synthesize the existing UTAUT extensions across both the dimensions and the levels of the research context and 2) highlight promising research directions. We conclude with recommendations for future UTAUT-related research using the proposed framework

    Specific IgE Response to Purified and Recombinant Allergens in Latex Allergy

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    Background In recent years, allergy to natural rubber latex has emerged as a major allergy among certain occupational groups and patients with underlying diseases. The sensitization and development of latex allergy has been attributed to exposure to products containing residual latex proteins. Although improved manufacturing procedures resulted in a considerable reduction of new cases, the potential risk for some patient groups is still great. In addition the prevalent cross-reactivity of latex proteins with other food allergens poses a major concern. A number of purified allergens and a few commercial kits are currently available, but no concerted effort was undertaken to evaluate them. Methods We studied 11 purified latex allergens, Hev b 1 to Hev b 10, and Hev b 13 along with several crude allergen extracts and two commercial ImmunoCAP assays to evaluate specific IgE antibody in the sera from latex allergic patients and controls. Health care workers and spina bifida patients with clinical symptoms of latex allergy, spina bifida patients without latex allergy, and non-atopic health care workers have been studied. Results The results suggest that Hev b 2, 5, 6, and 13 together identified over 80 percent health care workers with latex allergy, while Hev b 6 along with Hev b 1 or 3 detected specific IgE antibody in all sera studied from patients with spina bifida and latex allergy. The ImmunoCAP results using both Hev b 5 amplified and non-amplified closely agreed with the clinical diagnosis of latex allergy in health care workers and in spina bifida. Conclusion Although the purified allergens and crude extracts reacted diversely with IgE from different patient groups, the results indicated that use of certain combinations of purified recombinant antigens will be useful in commercial kits or in in-house assays for detecting specific IgE antibody in the sera. The results suggest that a combination of Hev b 2, 3, 5, 6, and 13 together detected specific IgE in 80% of the sera from latex allergic patients. Both ImmunoCAPs correctly identified over 95% of latex allergic patients, however, showed reactivity with a few normal control subject

    The Container Selection Problem

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    We introduce and study a network resource management problem that is a special case of non-metric k-median, naturally arising in cross platform scheduling and cloud computing. In the continuous d-dimensional container selection problem, we are given a set C of input points in d-dimensional Euclidean space, for some d >= 2, and a budget k. An input point p can be assigned to a "container point" c only if c dominates p in every dimension. The assignment cost is then equal to the L1-norm of the container point. The goal is to find k container points in the d-dimensional space, such that the total assignment cost for all input points is minimized. The discrete variant of the problem has one key distinction, namely, the container points must be chosen from a given set F of points. For the continuous version, we obtain a polynomial time approximation scheme for any fixed dimension d>= 2. On the negative side, we show that the problem is NP-hard for any d>=3. We further show that the discrete version is significantly harder, as it is NP-hard to approximate without violating the budget k in any dimension d>=3. Thus, we focus on obtaining bi-approximation algorithms. For d=2, the bi-approximation guarantee is (1+epsilon,3), i.e., for any epsilon>0, our scheme outputs a solution of size 3k and cost at most (1+epsilon) times the optimum. For fixed d>2, we present a (1+epsilon,O((1/epsilon)log k)) bi-approximation algorithm

    On the Exponentials of Some Structured Matrices

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    In this note explicit algorithms for calculating the exponentials of important structured 4 x 4 matrices are provided. These lead to closed form formulae for these exponentials. The techniques rely on one particular Clifford Algebra isomorphism and basic Lie theory. When used in conjunction with structure preserving similarities, such as Givens rotations, these techniques extend to dimensions bigger than four.Comment: 19 page

    The medial habenula: still neglected

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    The habenula is a small, bilateral brain structure located at the dorsal end of the diencephalon. This structure sends projections to the dopaminergic striatum and receives inputs from the limbic forebrain, making the habenula a unique modulator of cross-talk between these brain regions. Despite strong interest in the habenula during the seventies and eighties (Herkenham and Nauta, 1977; Beckstead, 1979; Beckstead et al., 1979; Herkenham and Nauta, 1979; Caldecott-Hazard et al., 1988), interest waned due to lack of a clearly identifiable functional role. Following Matsumoto and Hikosaka's seminal work on the lateral habenula as a predictor of negative reward in monkeys, the habenula has undergone a resurgence of scientific interest. Matsumoto and Hikosaka demonstrated an increase in habenular neuron firing when monkeys did not receive an expected juice reward (Matsumoto and Hikosaka, 2007). Studies have shown that increased habenular activity inactivates dopaminergic cells in the Rostromedial Tegmental Nucleus (RMTg) through GABAergic mechanisms (Jhou et al., 2009a,b). Additional studies link habenular activity to the regulation of serotonin and norepinephrine, suggesting the habenula modulates multiple brain systems (Strecker and Rosengren, 1989; Amat et al., 2001). These discoveries ushered in a series of new studies that have refocused attention on the lateral habenula and the importance of this small brain structure (Bianco and Wilson, 2009; Jhou et al., 2009a; Matsumoto and Hikosaka, 2009; Sartorius et al., 2010; Savitz et al., 2011). Recently, Geisler and Trimble reviewed this renewed interest in: The Lateral Habenula: No Longer Neglected (Geisler and Trimble, 2008). While the lateral habenula (LHb) has been extensively studied, the anatomically and histochemically distinct medial habenula (MHb) remains largely understudied. This short review argues that the MHb is functionally important and should be studied more aggressively

    METHOD DEVELOPMENT AND VALIDATION OF CLEANING PROCEDURE FOR FENBENDAZOLE RESIDUAL DETERMINATION IN MANUFACTURING

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    Objectives: Cleaning validation is the methodology used to assure that a cleaning process removes residues of the active pharmaceutical ingredientsof the product manufactured in a piece of equipment. All residues are removed to predetermined levels to ensure the quality of the next product.Today, manufactured is not compromised by waste from the previous product and the quality of future products using the equipment, to prevent crosscontamination, and as a good manufacturing practices requirement. The main aim of the study was to develop and validate a new simple, precise,and accurate reverse phase high-performance liquid chromatographic (HPLC) method for fenbendazole (FBZF) residual determination in veterinaryactive pharmaceutical ingredient manufacturing.Methods: The method was developed using the isocratic solvent system, HPLC grade acetonitrile, and Mill-Q water in the ratio of 60:40 (volume/volume), and 1% hydrochloric methanol is used as diluent. Successful elution of the FBZF was achieved on Waters Symmetry C-18 column with250 mm×4.6 mm internal diameter and 5 μm particle size.Results: The method validation was successfully applied for routine analysis for cleaning/residual samples. The developed reverse phase liquidchromatography method was validated with respect to specificity, linearity, accuracy, precision, and high sensitivity with detection limits andquantification limits ranging from 0.2 ppm to 15 ppm.Conclusion: The present developed and validated method is run successfully for FBZF residual determination of cleaning samples in veterinary activepharmaceutical ingredient manufacturing.Keywords: Fenbendazole, Residual determination, Reversed phase high-pressure liquid chromatography and cleaning validation

    The extended Malkus-Robbins dynamo as a perturbed Lorenz system

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    Recent investigations of some self-exciting Faraday-disk homopolar dynamo ([1-4]) have yielded the classic Lorenz equations as a special limit when one of the principal bifurcation parameters is zero. In this paper we focus upon one of those models [3] and illustrate what happens to some of the lowest order unstable periodic orbits as this parameter is increased from zero
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