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Absorption Effects (absorption + effects)
Selected AbstractsWATER ABSORPTION EFFECTS ON BIAXIAL EXTENSIONAL VISCOSITY OF WHEAT FLOUR DOUGHJOURNAL OF TEXTURE STUDIES, Issue 2 2003FERNANDO OSORIO ABSTRACT Biaxial extensional viscosities of wheat flour dough at three water absorption levels were determined as a function of biaxial strain rates using lubricated squeezing flow. The shape of the curves obtained in this study showed a sharp increase followed by a gradual increase which could indicate the presence of viscoelastic effects, which is not the usual case reported in the published literature for other products when using this technique. Plasticizing effect of water coupled with the effect of the starch and the interaction among the other components of wheat flour dough could explain the rheological behavior of flour dough during lubricated squeezing flow testing. Values of biaxial extensional viscosities of wheat flour dough for the three water absorption levels obtained in this study showed significant differences in the entire deformation range (P < 0.05). [source] Synchrotron-Based Micro-CT and Refraction-Enhanced Micro-CT for Non-Destructive Materials Characterisation,ADVANCED ENGINEERING MATERIALS, Issue 6 2009Bernd R. Müller Abstract X-ray computed tomography is an important tool for non-destructively evaluating the 3-D microstructure of modern materials. To resolve material structures in the micrometer range and below, high brilliance synchrotron radiation has to be used. The Federal Institute for Materials Research and Testing (BAM) has built up an imaging setup for micro-tomography and -radiography (BAMline) at the Berliner storage ring for synchrotron radiation (BESSY). In computed tomography, the contrast at interfaces within heterogeneous materials can be strongly amplified by effects related to X-ray refraction. Such effects are especially useful for materials of low absorption or mixed phases showing similar X-ray absorption properties that produce low contrast. The technique is based on ultra-small-angle scattering by microstructural elements causing phase-related effects, such as refraction and total reflection. The extraordinary contrast of inner surfaces is far beyond absorption effects. Crack orientation and fibre/matrix debonding in plastics, polymers, ceramics and metal-matrix-composites after cyclic loading and hydro-thermal aging can be visualized. In most cases, the investigated inner surface and interface structures correlate to mechanical properties. The technique is an alternative to other attempts on raising the spatial resolution of CT machines. [source] The dynamic behavior of magnetic colloids in suspensionJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2007Tina Autenrieth The dynamic behavior of magnetic colloidal particles in suspension is investigated. The particles of the core,shell colloid consist of a cobalt ferrite core embedded in a silica shell and are stabilized by surface charges. As the suspension is strongly opaque to visible light, it can not be probed by dynamic light scattering techniques as a result of strong multiple scattering as well as absorption effects. Therefore, the static and dynamic behavior is probed with small-angle X-ray scattering and X-ray photon correlation spectroscopy (XPCS), respectively. Using XPCS, we are able to study the diffusion coefficient of an opaque colloidal system as a function of the scattering vector. In this paper, we report on the behavior of the colloidal system in the absence of an external magnetic field, meaning that the magnetic moments of the particles are oriented randomly. We find no evidence for magnetic interactions in the static data, while the dynamic XPCS data deviate very significantly from the predictions of model calculations. [source] An XMM,Newton observation of Ark 120: the X-ray spectrum of a ,bare' Seyfert 1 nucleusMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2004S. Vaughan ABSTRACT We report on a long (100 ks) XMM,Newton observation of the bright Seyfert 1 galaxy Arakelian 120. The source previously showed no signs of intrinsic reddening in its infrared,ultraviolet continuum and previous observations had shown no evidence for ionized absorption in either the ultraviolet or X-ray bands. The new XMM,Newton Reflection Grating Spectrometer data place tight limits on the presence of an ionized X-ray absorber and confirm that the X-ray spectrum of Ark 120 is essentially unmodified by intervening matter. Thus Ark 120 can be considered a ,bare' Seyfert 1 nucleus. This observation therefore offers a clean view of the X-ray spectrum of a ,normal' Seyfert galaxy free from absorption effects. The spectrum shows a Doppler broadened iron emission line (FWHM , 3 × 104 km s,1) and a smooth, continuous soft excess which appears to peak at an energy ,0.5 keV. This adds weight to the claim that genuine soft excesses (i.e. those due to a real steepening of the underlying continuum below ,2 keV) are ubiquitous in Seyfert 1 spectra. However, the detailed shape of the excess could not be reproduced by any of the simple models tested (power laws, blackbodies, Comptonized blackbodies, accretion disc reflection). This observation therefore demonstrates both the need to understand the soft excess (as a significant contributor to the luminosity of most Seyfert 1s) and the inability of the existing, simple models to explain it. [source] X-ray spectroscopy of the intermediate polar PQ GemMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2002Cynthia H. James Abstract Using RXTE and ASCA data, we investigate the roles played by occultation and absorption in the X-ray spin pulse profile of the intermediate polar PQ Gem. From the X-ray light curves and phase-resolved spectroscopy, we find that the intensity variations are the result of a combination of varying degrees of absorption and the accretion regions rotating behind the visible face of the white dwarf. These occultation and absorption effects are consistent with those expected from the accretion structures calculated from optical polarization data. We can reproduce the changes in absorber covering fraction either from geometrical effects, or by considering that the material in the leading edge of the accretion curtain is more finely fragmented than in other parts of the curtain. We determine a white dwarf mass of , 1.2 using the RXTE data. [source] High-performance liquid chromatography coupled with mass spectrometry for the quantitative analysis of vinca-alkaloids in biological matrices: a concise survey from the literatureBIOMEDICAL CHROMATOGRAPHY, Issue 1 2010Carola W. N. Damen Abstract The bioanalysis of vinca-alkaloids has been investigated extensively. High-performance liquid chromatography coupled to ultraviolet, fluorescence or electrochemical detection have been described. During recent years liquid chromato-graphy coupled with mass spectrometry (LC-MS) has become the first choice for the quantitative bioanalysis of the vinca anticancer agents. This paper reviews recent methods for the bio-analysis of vinca-alkaloids using LC-MS, supplemented with our own experience. We will focus on sample pre-treatment, chromatography and MS detection and pay attention to problems which can occur during the bioanalysis of vinca-alkaloids. These problems encounter carry-over and absorption effects and solutions will be provided how to circumvent these problems. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||