961 research outputs found

    Compactness of nonlinear integral operators with discontinuous and with singular kernels

    Get PDF
    This paper establishes compactness of nonlinear integral operators in the space of continuous functions. One result deals with operators whose kernel can have jumps across a finite number of curves, which typically arise from the study of ordinary differential equations with boundary conditions of local or nonlocal type. Several other results deal with operators whose kernels have a singularity, which arise from the study of fractional differential equations. We motivate the study of these integral equations by discussing some initial value problems for fractional differential equations of Caputo and Riemann-Liouville type. We prove a compact embedding theorem for fractional integrals in order to give a new treatment for the singular kernel case

    Enhancement of R1234ze(Z) pool boiling heat transfer on horizontal titanium tubes for high-temperature heat pumps

    Get PDF
    R1234ze(Z), which has a global warming potential of less than 1, is a promising alternative refrigerant for hightemperatureheat pumps designed for heat recovery in the industrial sector. The use of titanium as the material for heat exchangers exposed to acid exhaust is one solution to prevent oxidation. In this study, the pool boiling heat transfer characteristics outside of horizontal titanium tubes were experimentally investigated for R1234ze(Z). Aplain tube and three enhanced titanium tubes were tested at saturation temperatures from 10 to 60 °C and heatfluxes from 0.55 to 79.8 kW m-2. Compared to the plain tube, the tested enhanced tube exhibited a 2.8 to 5.1 timeshigher heat transfer coefficient, on average, in the test range, which could compensate for the disadvantage in thethermal conductivity of titanium. The enhancement ratio predominantly depends on the saturation temperatureand the wall heat flux. At conditions of higher saturation temperatures and lower heat flux, where smaller bubblesare observed, test tubes with smaller fin spaces exhibit higher heat transfer coefficients. The experimental resultsindicate the importance of fin geometry optimization to the operation conditions

    Effects of simulated error-sources on different 3-D CSI-EPT strategies

    Get PDF
    Three-dimensional contrast source inversion-electrical properties tomography (3-D CSI-EPT) is an iterative reconstruction method that estimates the electrical properties of tissue from transmit field magnetic resonance data. However, in order to bring 3-D CSI-EPT into practice for complex tissue structures and to understand the origin and effect of errors, insight in the sensitivities of reconstruction accuracy to the major error-sources is necessary. In this paper, different strategies for implementing 3-D CSI-EPT, including their iterative structure, are presented, of which the regularized implementation shows the most potential to be used in practice. Moreover, the influence of initialization, noise, stopping criteria, incident fields, B1-maps, transceive phase and domain truncation are discussed. We show that of all these different error-sources, initialization, accurate coil models and domain truncation have the most dramatic effect on electrical properties reconstructions in practice.Imaging- and therapeutic targets in neoplastic and musculoskeletal inflammatory diseas

    Fundamental Physical Constants: Looking from Different Angles

    Full text link
    We consider fundamental physical constants which are among a few of the most important pieces of information we have learned about Nature after its intensive centuries-long studies. We discuss their multifunctional role in modern physics including problems related to the art of measurement, natural and practical units, origin of the constants, their possible calculability and variability etc

    Computed tomography image of the mediastinal and axillary lymph nodes in clinically sound Rottweilers

    Full text link
    Trough computed tomography (CT), it is possible to evaluate lymph nodes in detail and to detect changes in these structures earlier than with radiographs and ultrasound. Lack of information in the veterinary literature directed the focus of this report to normal aspects of the axillary and mediastinal lymph nodes of adult dogs on CT imaging. A CT scan of 15 normal adult male and female Rottweilers was done. To define them as clinically sound, anamnesis, physical examination, complete blood count, renal and hepatic biochemistry, ECG, and thoracic radiographs were performed. After the intravenous injection of hydrosoluble ionic iodine contrast medium contiguous 10mm in thickness thoracic transverse images were obtained with an axial scanner. In the obtained images mediastinal and axillary lymph nodes were sought and when found measured in their smallest diameter and their attenuation was compared to musculature. Mean and standard deviation of: age, weight, body length and the smallest diameter of the axillary and mediastinal lymph nodes were determined. Mean and standard deviation of parameters: age 3.87±2.03 years, weight 41.13±5.12, and body length 89.61±2.63cm. Axillary lymph nodes were seen in 60% of the animals, mean of the smallest diameter was 3.58mm with a standard deviation of 2.02 and a minimum value of 1mm and a maximum value of 7mm. From 13 observed lymph nodes 61.53% were hypopodense when compared with musculature, and 30.77% were isodense. Mediastinal lymph nodes were identified in 73.33% of the dogs; mean measure of the smallest diameter was 4.71mm with a standard deviation of 2.61mm and a minimum value of 1mm, and a maximum value of 8mm. From 14 observed lymph nodes 85.71% were isodense when compared with musculature and 14.28% were hypodense. The results show that it is possible to visualize axillary and mediastinal lymph nodes in adult clinically sound Rottweilers with CT using a slice thickness and interval of 10mm. The smallest diameter of the axillary and mediastinal lymph nodes not surpassed 7mm and 8mm respectively. Their attenuations were equal or smaller than that of musculature in the post contrast scan

    Postmodern professions? The fragmentation of legal education and the legal profession

    Get PDF
    This article considers the institutional dimensions of professionalism and the legal profession's struggle with the challenges of post-modernity. An aspect of this is the Law Society's Training Framework Review (TFR) which promises changes to solicitors' education from 'cradle to grave'. The first part of the article analyses the structure and drivers of the TFR, their origins, and how they will be articulated. Secondly, the TFR is considered in the context of the political economy of higher education and its role in the new capitalism. Finally, we examine the potential effects of the TFR for the legal profession in the context of increasing practice segmentation and the threat of deprofessionalization, and also for the Law Society itself, whether it can retain a key role in the life course of the legal profession

    'Education, education, education' : legal, moral and clinical

    Get PDF
    This article brings together Professor Donald Nicolson's intellectual interest in professional legal ethics and his long-standing involvement with law clinics both as an advisor at the University of Cape Town and Director of the University of Bristol Law Clinic and the University of Strathclyde Law Clinic. In this article he looks at how legal education may help start this process of character development, arguing that the best means is through student involvement in voluntary law clinics. And here he builds upon his recent article which argues for voluntary, community service oriented law clinics over those which emphasise the education of students

    Some Uses and Potentials of Qualitative Methods in Planning

    Get PDF
    Planners use methods borrowed from many disciplines. These are usually modified and adapted to meet planner's needs to acquire and sift through many diverse information sources helpful in dealing with complex problems. The quantitative methods which planners use are well known, well established in practice, and acknowledged by most as tools of the planners' trade. In contrast to this, most planners also use qualitative methods but these are rarely explicitly acknowledged.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68912/2/10.1177_0739456X8600600110.pd

    Single Spin Asymmetry ANA_N in Polarized Proton-Proton Elastic Scattering at s=200\sqrt{s}=200 GeV

    Get PDF
    We report a high precision measurement of the transverse single spin asymmetry ANA_N at the center of mass energy s=200\sqrt{s}=200 GeV in elastic proton-proton scattering by the STAR experiment at RHIC. The ANA_N was measured in the four-momentum transfer squared tt range 0.003â©œâˆŁtâˆŁâ©œ0.0350.003 \leqslant |t| \leqslant 0.035 \GeVcSq, the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of ANA_N and its tt-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the single spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated by the Pomeron amplitude at this s\sqrt{s}, we conclude that this measurement addresses the question about the presence of a hadronic spin flip due to the Pomeron exchange in polarized proton-proton elastic scattering.Comment: 12 pages, 6 figure
    • 

    corecore