240 research outputs found

    Least-squares solution of incompressible Navier-Stokes equations with the p-version of finite elements

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    A p-version of the least squares finite element method, based on the velocity-pressure-vorticity formulation, is developed for solving steady state incompressible viscous flow problems. The resulting system of symmetric and positive definite linear equations can be solved satisfactorily with the conjugate gradient method. In conjunction with the use of rapid operator application which avoids the formation of either element of global matrices, it is possible to achieve a highly compact and efficient solution scheme for the incompressible Navier-Stokes equations. Numerical results are presented for two-dimensional flow over a backward facing step. The effectiveness of simple outflow boundary conditions is also demonstrated

    TE Wave Measurement and Modeling

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    In the TE wave method, microwaves are coupled into the beam-pipe and the effect of the electron cloud on these microwaves is measured. An electron cloud (EC) density can then be calculated from this measurement. There are two analysis methods currently in use. The first treats the microwaves as being transmitted from one point to another in the accelerator. The second more recent method, treats the beam-pipe as a resonant cavity. This paper will summarize the reasons for adopting the resonant TE wave analysis as well as give examples from CESRTA and DA{\Phi}NE of resonant beam-pipe. The results of bead-pull bench measurements will show some possible standing wave patterns, including a cutoff mode (evanescent) where the field decreases exponentially with distance from the drive point. We will outline other recent developments in the TE wave method including VORPAL simulations of microwave resonances, as well as the simulation of transmission in the presence of both an electron cloud and magnetic fields.Comment: Presented at ECLOUD'12: Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects, La Biodola, Isola d'Elba, Italy, 5-9 June 2012; CERN-2013-002, pp. 193-20

    IMAGE FUSION ALGORITHM FOR FUSION OF PANCHROMATIC AND MULTISPECTRAL IMAGES FOR HIGH SPATIAL INFORMATION WHILE PRESERVING SPECTRAL INFORMATION CONTENT

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    In this paper image fusion algorithm for enhancing spatial quality of the multispectral image while maintaining the spectral quality of the multispectral image is proposed. The fusion algorithm is developed based on high frequency components injection to the multispectral image to improve the spatial quality of the fused image. High frequency component is generated using the Laplacian filter. Construct the saliency map and initial weight map. Finally optimum weight parameter is calculated for each band using the guided filter, using this optimum weight parameter panchromatic and multispectral images are fused to enhance the spatial quality of the multispectral image

    Observation of Electron Clouds in the ANKA Undulator by Means of the Microwave Transmission Method

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    A superconducting undulator is installed in the ANKA electron storage ring. Electron clouds could potentially contribute to the heat load of this device. A microwave transmission type electron cloud diagnostic has been installed for the undulator section of the ANKA machine. We present the system layout with particular emphasis on the electron machine aspects. Hardware transfer function results and e-cloud data for different machine settings are discussed. Special care has been taken for front end filter design both on the microwave injection and pick-up side

    Diffusion of published cost-utility analyses in the field of health policy and practice

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    OBJECTIVES: The diffusion of cost-utility analyses (CUAs) through the medical literature was examined, documenting visible patterns and determining how they correspond with expectations about the diffusion of process innovations. METHODS: This study used 539 CUAs from a registry. It includes data elements comprising year of publication, the research center in which the study was performed, the clinical area covered by the CUA, and the specific journal. Finally, each paper was assigned to a journal type that could be one of the three categories: health services research, general medicine, or clinical specialty. RESULTS: When the average number of publications is plotted against time, the plot reveals an S-shaped curve. It appears that, whereas CUAs initially were published more frequently in general medical or health services research journals, there was a clear increase in the diffusion of CUA into subspecialty journals over time. The concentration ratio for research centers as measured by the Herfindhal-Hirschman Index decreased over time. CONCLUSIONS: The spread of CUA through the medical literature follows patterns identified for the diffusion of other new technologies and processes. Future research should focus on what impact this spread has had on the practice of medicine and formulation of health policy

    Knowledge of hepatitis C screening and management by internal medicine residents: trends over 2 years

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    Over 2 million people in the United States are infected with hepatitis C, and there has been an explosion in knowledge regarding this disease in the last decade. Internal medicine residents must be able to identify patients at risk for hepatitis C and institute appropriate diagnostic testing and referral of these patients. Methods : A survey regarding hepatitis C risk factors and the management of hepatitis C patients was administered on three occasions over 15 months (time 0, 1 month, and 15 months) to members of a large university-based internal medicine residency. Results : During the study period 59 residents completed all three surveys. Less than half of the residents (39%) ask patients about hepatitis C risk factors. Only 58% reported that they would refer a hepatitis C antibody positive patient with elevated liver enzymes to a subspecialist on the initial survey. The residents who did not refer patients cited low response rates, high side-effect profiles, and the high cost of therapy as reasons for not referring the patient. There was significant improvement (58% vs 78%, p < 0.01 ) in the rate of patient referral during the 15-month study period but no substantial improvement in the other knowledge deficits. Conclusions : The knowledge base of the internal medicine residents about hepatitis C screening and management is suboptimal. New, more effective hepatitis C education programs for internal medicine residents should be initiated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75407/1/j.1572-0241.2002.05708.x.pd
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