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Constant Flux (constant + flux)
Selected AbstractsSolution of the unsaturated soil moisture equation using repeated transformsINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 15 2001S. G. Fityus Abstract An alternative method of solution for the linearized ,theta-based' form of the Richards equation of unsaturated flow is developed in two spatial dimensions. The Laplace and Fourier transformations are employed to reduce the Richards equation to an ordinary differential equation in terms of a transformed moisture content and the transform variables, s and ,. Separate analytic solutions to the transformed equation are developed for initial states which are either in equilibrium or dis-equilibrium. The solutions are assembled into a finite layer formulation satisfying continuity of soil suction, thereby facilitating the analysis of horizontally stratified soil profiles. Solution techniques are outlined for various boundary conditions including prescribed constant moisture content, prescribed constant flux and flux as a function of moisture change. Example solutions are compared with linearized finite element solutions. The agreement is found to be good. An adaptation of the method for treating the quasilinearized Richards equation with variable diffusivity is also described. Comparisons of quasilinear solutions with some earlier semi-analytical, finite element and finite difference results are also favourable. Copyright © 2001 John Wiley & Sons, Ltd. [source] Knowing , in MedicineJOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 5 2008Joachim P. Sturmberg MBBS DORACOG MFM PhD FRACGP Abstract In this paper we argue that knowledge in health care is a multidimensional dynamic construct, in contrast to the prevailing idea of knowledge being an objective state. Polanyi demonstrated that knowledge is personal, that knowledge is discovered, and that knowledge has explicit and tacit dimensions. Complex adaptive systems science views knowledge simultaneously as a thing and a flow, constructed as well as in constant flux. The Cynefin framework is one model to help our understanding of knowledge as a personal construct achieved through sense making. Specific knowledge aspects temporarily reside in either one of four domains , the known, knowable, complex or chaotic, but new knowledge can only be created by challenging the known by moving it in and looping it through the other domains. Medical knowledge is simultaneously explicit and implicit with certain aspects already well known and easily transferable, and others that are not yet fully known and must still be learned. At the same time certain knowledge aspects are predominantly concerned with content, whereas others deal with context. Though in clinical care we may operate predominately in one knowledge domain, we also will operate some of the time in the others. Medical knowledge is inherently uncertain, and we require a context-driven flexible approach to knowledge discovery and application, in clinical practice as well as in health service planning. [source] Emerging drugs: mechanism of action, mass spectrometry and doping control analysisJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 4 2009Mario Thevis Abstract The number of compounds and doping methods in sports is in a state of constant flux. In addition to ,traditional' doping agents, such as anabolic androgenic steroids or erythropoietin, new therapeutics and emerging drugs have considerable potential for misuse in elite sport. Such compounds are commonly based on new chemical structures, and the mechanisms underlying their modes of action represent new therapeutic approaches arising from recent advances in medical research; therefore, sports drug testing procedures need to be continuously modified and complementary methods developed, preferably based on mass spectrometry, to enable comprehensive doping controls. This tutorial not only discusses emerging drugs that can be categorized as anabolic agents (selective androgen receptor modulators, SARMs), gene doping [hypoxia-inducible factor stabilizers, peroxisome-proliferator-activated receptor (PPAR),-agonists] and erythropoietin-mimetics (Hematide) but also compounds with potentially performance-enhancing properties that are not classified in the current list of the World Anti-Doping Agency. Compounds such as ryanodine-calstabin-complex modulators (benzothiazepines) are included, their mass spectrometric properties discussed, and current approaches in sports drug testing outlined. Copyright © 2009 John Wiley & Sons, Ltd. [source] Variable-period undulators as synchrotron radiation sourcesJOURNAL OF SYNCHROTRON RADIATION, Issue 3 2003G. K. Shenoy A concept for variable-period undulators for the production of synchrotron radiation from both medium- and high-energy storage rings is described. This concept is based on a staggered array of permeable poles placed in a magnetic solenoid that produces a longitudinal field. The concept permits variations in the short magnetic period of the undulator of as much as 100%. The unique capabilities of such undulators will allow them to be tuned by the variation of the period length and of the solenoid field. The device can be operated at either constant flux or constant power, independent of X-ray energy. It is expected that the new concept will have a major impact on the production and applications of X-rays because of the inherent simplicity and flexibility of the design and the absence of radiation damage. Analyses of the magnetic and mechanical design concepts are presented. [source] | ||||||||||