970 resultados para irradiation uniformity of laser


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Vascular birthmarks can be classified into hemangioma and vascular malformations. Hemangioma are frequent tumours of early infancy demonstrating endothelial hyperplasia, a history of rapid neonatal growth and slow involution during later childhood. Treatment of hemangioma is dependent of stage and type of the lesion. Given the current availability of drugs, lasers, and other techniques to treat hemangioma safely, philosophy of "benign neglect" should not be considered anymore. Vascular malformations show a normal endothelial turnover, being present at birth and growing commensurately with the child. Exact diagnosis by employing modern diagnostic means,which are able to differentiate low-flow from high flow lesions is important for further therapeutic management. Beside conservative treatment strategies, use of laser, sclerotherapy, interventional embolization and surgical treatment are possible management options. Patients should receive multidisciplinary care in qualified vascular centres.

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Meprin (EC 3.4.24.18) is an oligomeric metalloendopeptidase found in microvillar membranes of kidney proximal tubular epithelial cells. Here, we present the first report on the expression of meprin beta in rat glomerular epithelial cells and suggest a potential involvement in experimental glomerular disease. We detected meprin beta in glomeruli of immunostained rat kidney sections on the protein level and by quantitative RT-PCR of laser-capture microdissected glomeruli on the mRNA level. Using immuno-gold staining we identified the membrane of podocyte foot processes as the main site of meprin beta expression. The glomerular meprin beta expression pattern was altered in anti-Thy 1.1 and passive Heymann nephritis (PHN). In addition, the meprin beta staining pattern in the latter was reminiscent of immunostaining with the sheep anti-Fx1A antiserum, commonly used in PHN induction. Using Western blot and immunoprecipitation assays we demonstrated that meprin beta is recognized by Fx1A antiserum and may therefore represent an auto-antigen in PHN. In anti-Thy 1.1 glomerulonephritis we observed a striking redistribution of meprin beta in tubular epithelial cells from the apical to the basolateral side and the cytosol. This might point to an involvement of meprin beta in this form of glomerulonephritis.

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During the past decade microbeam radiation therapy has evolved from preclinical studies to a stage in which clinical trials can be planned, using spatially fractionated, highly collimated and high intensity beams like those generated at the x-ray ID17 beamline of the European Synchrotron Radiation Facility. The production of such microbeams typically between 25 and 100 microm full width at half maximum (FWHM) values and 100-400 microm center-to-center (c-t-c) spacings requires a multislit collimator either with fixed or adjustable microbeam width. The mechanical regularity of such devices is the most important property required to produce an array of identical microbeams. That ensures treatment reproducibility and reliable use of Monte Carlo-based treatment planning systems. New high precision wire cutting techniques allow the fabrication of these collimators made of tungsten carbide. We present a variable slit width collimator as well as a single slit device with a fixed setting of 50 microm FWHM and 400 microm c-t-c, both able to cover irradiation fields of 50 mm width, deemed to meet clinical requirements. Important improvements have reduced the standard deviation of 5.5 microm to less than 1 microm for a nominal FWHM value of 25 microm. The specifications of both devices, the methods used to measure these characteristics, and the results are presented.

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Durch die neuen systemtechnischen Möglichkeiten erfährt das Laserstrahlsintern von Polyaryletherketonen wie PEK oder PEEK zunehmendes industrielles Interesse. Neben der höheren Festigkeit, Steifigkeit und Temperaturbeständigkeit z. B. laserstrahlgesinterter PEEK Bauteile gegenüber den bisher für Funktionsprototypen und für das Rapid Manufacturing eingesetzten Polyamidbauteilen sind Fragen nach der erzielbaren Bauteilgenauigkeit und des minimal möglichen Auflösungsvermögens insbesondere für die Fertigung kleiner Bauteile von besonderer Bedeutung. In diesem Beitrag werden die Abhängigkeiten der Einflussgrößen Schwund und Strahlweite von den wichtigsten Prozessführungsgrößen untersucht und die Möglichkeiten und Grenzen zur Erzeugung kleiner Bauteilstrukturen mittels Laserstrahlsintern von PEEK aufgezeigt.

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Nicht nur die vielfältigen funktionsbezogenen Anforderungen von Produkten und Bauteilen, sondern vor allem die heutigen Marktbedürfnisse stellen große Herausforderungen für aktuelle Fertigungstechnologien dar. Hierbei bildet die kontinuierlich steigende Variantenvielfalt bei gleichzeitiger Senkung der Stückzahlen je Variante die differenzierten Kundenwünsche ab. Diese Entwicklungen begünstigen die Perspektiven des Laserstrahlschmelzens im Allgemeinen sowie seiner speziellen Anwendungsgebiete Rapid Prototyping, Rapid Tooling und Rapid Manufac-turing. In den Branchen der Medizintechnik und der Gummi- und Kunststoffverarbeitung ist bereits seit einiger Zeit eine dynamische Entwicklung erkennbar. Besonders in der Medizintechnik wird der immer breitere Einsatz des Laserstrahlschmelzens durch die hohe Innovationsfähigkeit des Verfahrens und ein verbesserstes Qualitäts-management vorangetrieben. Aufgrund der zunehmenden Forderungen nach individualisierten und individuellen Produkten werden bereits heute patientenangepasste Implantate mit dem Laserstrahlschmelzverfahren gefertigt. Erwarten die Marktteilnehmer eine weiterhin steigende Nachfrage nach solchen Produkten? Wie muss das Verfah-ren verbessert werden, um seine Prozessstabilität zu erhöhen? Wo liegen die zukünftigen Herausforderungen in der Strahlschmelztechnologie? Um diese und weitere Fragen zu klären hat das Fraunhofer Institut für Produkti-onsanlagen und Konstruktionstechnik (IPK) eine Markt- und Trendanalyse für das Laserstrahlschmelzen durchge-führt.

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Werkzeugbauer stellen anspruchsvolle Spritzgießwerkzeuge als Einzelanfertigung oder in kleiner Stückzahl her. Dabei unterliegen sie einem hohen Zeit- und Kostendruck durch die Forderung der Kunden nach einer kurzen Time-to-Market und der Konkurrenz aus Niedriglohnländern. Eine Innovation des Werkzeugbaus zur Reduzierung von Zeit und Kosten ist die Integration von zusätzlichen Funktionen in bestehende Komponenten. Am Institut für Laser- und Anlagensystemtechnik der TU Hamburg-Harburg wurde in Zusammenarbeit mit Werkzeugbau Siegfried Hofmann und Concept Laser ein Druckluftauswerfersystem für Spritzgießwerkzeuge entwickelt. Dieses System kann klassische Auswerferstifte vollständig ersetzen. Die Integration von Druckluftauswerfern in laseradditiv gefertigte Werkzeugeinsätze mit konturnaher Kühlung erfolgt kostenneutral, da sich die Fertigungszeit des Einsatzes durch das zusätzliche System nicht verlängert und eine Druckluftsteuerung bereits in Spritzgießmaschinen vorhanden ist. Zusätzlich entfällt durch das Druckluftauswerfersystem das komplette mechanische Auswerferpaket. Durch diese Einsparungen reduzieren sich Zeit und Kosten für das Werkzeug.

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Difficult to control atopic dermatitis (AD) presents a therapeutic challenge and often requires combinations of topical and systemic treatment. Anti-inflammatory treatment of severe AD most commonly includes topical glucocorticosteroids and topical calcineurin antagonists used for exacerbation management and more recently for proactive therapy in selected cases. Topical corticosteroids remain the mainstay of therapy, the topical calcineurin inhibitors tacrolimus and pimecrolimus are preferred in certain locations. Systemic anti-inflammatory treatment is an option for severe refractory cases. Microbial colonization and superinfection contribute to disease exacerbation and thus justify additional antimicrobial / antiseptic treatment. Systemic antihistamines (H1) may relieve pruritus but do not have sufficient effect on eczema. Adjuvant therapy includes UV irradiation preferably of UVA1 wavelength. "Eczema school" educational programs have been proven to be helpful.

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Tungsten isotope compositions of magmatic iron meteorites yield ages of differentiation that are within ±2 Ma of the formation of CAIs, with the exception of IVB irons that plot to systematically less radiogenic compositions yielding erroneously old ages. Secondary neutron capture due to galactic cosmic ray (GCR) irradiation is known to lower the ε182W of iron meteorites, adequate correction of which requires a measure of neutron dosage which has not been available, thus far. The W, Os and Pt isotope systematics of 12 of the 13 known IVB iron meteorites were determined by MC-ICP-MS (W, Os, Pt) and TIMS (Os). On the same dissolutions that yield precise ε182W, stable Os and Pt isotopes were determined as in situ neutron dosimeters for empirical correction of the ubiquitous cosmic-ray induced burn-out of 182W in iron meteorites. The W isotope data reveal a main cluster with ε182W of ∼−3.6, but a much larger range than observed in previous studies including irons (Weaver Mountains and Warburton Range) that show essentially no cosmogenic effect on their ε182W. The IVB data exhibits resolvable negative anomalies in ε189Os (−0.6ε) and complementary ε190Os anomalies (+0.4ε) in Tlacotepec due to neutron capture on 189Os which has approximately the same neutron capture cross section as 182W, and captures neutrons to produce 190Os. The least irradiated IVB iron, Warburton Range, has ε189Os and ε190Os identical to terrestrial values. Similarly, Pt isotopes, which are presented as ε192Pt, ε194Pt and ε196Pt range from +4.4ε to +53ε, +1.54ε to −0.32ε and +0.73ε to −0.20ε, respectively, also identify Tlacotepec and Dumont as the most GCR-damaged samples. In W–Os and W–Pt isotope space, the correlated isotope data back-project toward a 0-epsilon value of ε192Pt, ε189Os and ε190Os from which a pre-GCR irradiation ε182W of −3.42±0.09 (2σ) is derived. This pre-GCR irradiation ε182W is within uncertainty of the currently accepted CAI initial ε182W. The Pt and Os isotope correlations in the IVB irons are in good agreement with a nuclear model for spherical irons undergoing GCR spallation, although this model over-predicts the change of ε182W by ∼2×, indicating a need for better W neutron capture cross section determinations. A nucleosynthetic effect in ε184W in these irons of −0.14±0.08 is confirmed, consistent with the presence of Mo and Ru isotope anomalies in IVB irons. The lack of a non-GCR Os isotope anomaly in these irons requires more complex explanations for the production of W, Ru and Mo anomalies than nebular heterogeneity in the distribution of s-process to r-process nuclides.

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We propose notions of calibration for probabilistic forecasts of general multivariate quantities. Probabilistic copula calibration is a natural analogue of probabilistic calibration in the univariate setting. It can be assessed empirically by checking for the uniformity of the copula probability integral transform (CopPIT), which is invariant under coordinate permutations and coordinatewise strictly monotone transformations of the predictive distribution and the outcome. The CopPIT histogram can be interpreted as a generalization and variant of the multivariate rank histogram, which has been used to check the calibration of ensemble forecasts. Climatological copula calibration is an analogue of marginal calibration in the univariate setting. Methods and tools are illustrated in a simulation study and applied to compare raw numerical model and statistically postprocessed ensemble forecasts of bivariate wind vectors.

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En un área de aprox. 2 000 000 ha del sur de Córdoba (Argentina) se evaluaron los equipos de riego con el fin de conocer su funcionamiento, el grado de uniformidad con que trabajan y la eficiencia de riego lograda por los productores. Se realizaron 21 evaluaciones sobre equipos operando de acuerdo con la programación establecida por sus usuarios; 14 sobre pivote, una sobre avance lateral, 4 sobre enrolladores (3 de cañón y uno de baja presión) y 2 sobre side roll. Los parámetros de calidad de riego brindaron coeficiente medio de uniformidad = 81,4 %, con uniformidad de distribución = 73,23 %. En el 80 % de los casos, la lámina aplicada fluctuó entre 10 y 20 mm siendo su promedio = 17 mm. De los resultados se puede inferir que -en general- la superficie asignada a cada equipo es siempre mayor que su capacidad para realizar oportunamente una óptima reposición del agua al suelo y que, si bien los coeficientes de uniformidad y distribución del agua pueden considerarse aceptables, la programación del riego es mala en todos los establecimientos evaluados poniéndose de manifiesto en la baja eficiencia de almacenamiento y repercutiendo directamente sobre la producción de los cultivos regados.

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El presente trabajo tiene por objeto evaluar la uniformidad del riego por goteo en las zonas de regadío de las cuencas de los ríos Mendoza y Tunuyán (zonas Alta y Baja), de la provincia de Mendoza, Argentina. Las evaluaciones -en 17 propiedades- permitieron determinar: coeficientes de uniformidad, salinidad del agua de riego y del suelo en cabeza, medio y pie de la subunidad de riego, y en el bulbo húmedo e interfilar en dos estratos del perfil del suelo (0,10‑0,30 m y 0,30-0,50 m). Se determinó, además, la textura del suelo y su posible relación con los niveles de salinidad de la rizósfera. Se estimó que el 18% de las subunidades de riego evaluadas presentan un coeficiente de uniformidad por debajo del rango recomendable y que en el 94% de las propiedades existen diferencias significativas entre caudales medios registrados entre subunidades y entre sectores de operación de riego. Se encontraron diferencias significativas en la salinidad del extracto de saturación, en la sodicidad y en la concentración del anión cloruro, al comparar el suelo extraído del bulbo de mojado respecto del interfilar. Asimismo, los resultados muestran que no existen diferencias significativas de esas variables en las distintas profundidades de suelo analizadas. El aumento de la salinidad resultó en función del lugar de muestreo (bulbo o interfilar), la calidad del agua de riego y la textura del suelo. La variación de sodicidad, en cambio, dependió del lugar de muestreo (bulbo o interfilar) y del contenido de bicarbonatos en el suelo. Los resultados indican la importancia de realizar evaluaciones rutinarias del comportamiento de los sistemas de riego en términos de uniformidad y salinización inducida.

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This dataset present result from the DFG- funded Arctic-Turbulence-Experiment (ARCTEX-2006) performed by the University of Bayreuth on the island of Svalbard, Norway, during the winter/spring transition 2006. From May 5 to May 19, 2006 turbulent flux and meteorological measurements were performed on the monitoring field near Ny-Ålesund, at 78°55'24'' N, 11°55'15'' E Kongsfjord, Svalbard (Spitsbergen), Norway. The ARCTEX-2006 campaign site was located about 200 m southeast of the settlement on flat snow covered tundra, 11 m to 14 m above sea level. The permanent sites used for this study consisted of the 10 m meteorological tower of the Alfred Wegener Institute for Polar- and Marine Research (AWI), the international standardized radiation measurement site of the Baseline Surface Radiation Network (BSRN), the radiosonde launch site and the AWI tethered balloon launch sites. The temporary sites - set up by the University of Bayreuth - were a 6 m meteorological gradient tower, an eddy-flux measurement complex (EF), and a laser-scintillometer section (SLS). A quality assessment and data correction was applied to detect and eliminate specific measurement errors common at a high arctic landscape. In addition, the quality checked sensible heat flux measurements are compared with bulk aerodynamic formulas that are widely used in atmosphere-ocean/land-ice models for polar regions as described in Ebert and Curry (1993, doi:10.1029/93JC00656) and Launiainen and Cheng (1995). These parameterization approaches easily allow estimation of the turbulent surface fluxes from routine meteorological measurements. The data show: - the role of the intermittency of the turbulent atmospheric fluctuation of momentum and scalars, - the existence of a disturbed vertical temperature profile (sharp inversion layer) close to the surface, - the relevance of possible free convection events for the snow or ice melt in the Arctic spring at Svalbard, and - the relevance of meso-scale atmospheric circulation pattern and air-mass advection for the near-surface turbulent heat exchange in the Arctic spring at Svalbard. Recommendations and improvements regarding the interpretation of eddy-flux and laser-scintillometer data as well as the arrangement of the instrumentation under polar distinct exchange conditions and (extreme) weather situations could be derived.

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During Leg 127, the formation microscanner (FMS) logging tool was used as part of an Ocean Drilling Program (ODP) logging program for only the second time in the history of the program. Resistivity images, also known as FMS logs, were obtained at Sites 794 and 797 that covered nearly the complete Yamato Basin sedimentary sequence to a depth below 500 mbsf. The FMS images from these two sites at the northeastern and southwestern corners of the Yamato Basin thus were amenable to comparison. A strong visual correlation was noticed between the FMS logs taken in Holes 794B and 797C in an upper Miocene interval (350-384 mbsf), although the two sites are approximately 360 km apart. In this interval, the FMS logs showed a series of more resistive thin beds (10-200 cm) alternating with relatively lower resistivity layers: a pattern that was manifested by alternating dark (low resistivity) and light (high resistivity) banding in the FMS images. We attribute this layering to interbedding of chert and porcellanite layers, a common lithologic sequence throughout Japan (Tada and Iijima, 1983, doi:10.1306/212F82E7-2B24-11D7-8648000102C1865D). Spatial frequency analysis of this interval of dominant dark-light banding showed spatial cycles of period of 1.1 to 1.3 and 0.6 m. This pronounced layering and the correlation between the two sites terminate at 384 mbsf, coincident with the opal-CT to quartz transition at Site 794. We think the correlation in the FMS logs might well extend earlier in the middle Miocene, but the opal-CT to quartz transition obscures this layering below 384 mbsf. Although 34 m is only a small part of the core recovered at these two sites, it is significant because it represents an area of extremely poor core recovery and an interval for which a near-depositional hiatus was postulated for Site 797, but not for Site 794.

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HiPER is the European Project for Laser Fusion that has been able to join 26 institutions and signed under formal government agreement by 6 countries inside the ESFRI Program of the European Union (EU). The project is already extended by EU for two years more (until 2013) after its first preparatory phase from 2008. A large work has been developed in different areas to arrive to a design of repetitive operation of Laser Fusion Reactor, and decisions are envisioned in the next phase of Technology Development or Risk Reduction for Engineering or Power Plant facilities (or both). Chamber design has been very much completed for Engineering phase and starting of preliminary options for Reactor Power Plant have been established and review here.

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Este proyecto, titulado “Caracterización de colectores para concentración fotovoltaica”, consiste en una aplicación en Labview para obtener las características de los elementos ópticos utilizados en sistemas de concentración fotovoltaica , atendiendo a la distribución espacial del foco de luz concentrado que generan. Un sistema de concentración fotovoltaica utiliza un sistema óptico para transmitir la radiación luminosa a la célula solar aumentando la densidad de potencia luminosa. Estos sistemas ópticos están formados por espejos o lentes para recoger la radiación incidente en ellos y concentrar el haz de luz en una superficie mucho menor. De esta manera se puede reducir el área de material semiconductor necesario, lo que conlleva una importante reducción del coste del sistema. Se pueden distinguir diferentes sistemas de concentración dependiendo de la óptica que emplee, la estructura del receptor o el rango de concentración. Sin embargo, ya que el objetivo es analizar la distribución espacial, diferenciaremos dos tipos de concentradores dependiendo de la geometría que presenta el foco de luz. El concentrador lineal o cilíndrico que enfoca sobre una línea, y el concentrador de foco puntual o circular que enfoca la luz sobre un punto. Debido a esta diferencia el análisis en ambos casos se realizará de forma distinta. El análisis se realiza procesando una imagen del foco tomada en el lugar del receptor, este método se llama LS-CCD (Difusión de luz y captura con CCD). Puede utilizarse en varios montajes dependiendo si se capta la imagen por reflexión o por transmisión en el receptor. En algunos montajes no es posible captar la imagen perpendicular al receptor por lo que la aplicación realizará un ajuste de perspectiva para obtener el foco con su forma original. La imagen del foco ofrece información detallada acerca de la uniformidad del foco mediante el mapa de superficie, que es una representación en 3D de la imagen pero que resulta poco manejable. Una representación más sencilla y útil es la que ofrecen los llamados “perfiles de intensidad”. El perfil de intensidad o distribución de la irradiancia que representa la distribución de la luz para cada distancia al centro, y el perfil acumulado o irradiancia acumulada que representa la luz contenida en relación también al centro. Las representaciones de estos perfiles en el caso de un concentrador lineal y otro circular son distintas debido a su diferente geometría. Mientras que para un foco lineal se expresa el perfil en función de la semi-anchura del receptor, para uno circular se expresa en función del radio. En cualquiera de los casos ofrecen información sobre la uniformidad y el tamaño del foco de luz necesarios para diseñar el receptor. El objetivo de este proyecto es la creación de una aplicación software que realice el procesado y análisis de las imágenes obtenidas del foco de luz de los sistemas ópticos a caracterizar. La aplicación tiene una interfaz sencilla e intuitiva para que pueda ser empleada por cualquier usuario. Los recursos necesarios para realizar el proyecto son: un PC con sistema operativo Windows, el software Labview 8.6 Professional Edition y los módulos NI Vision Development Module (para trabajar con imágenes) y NI Report Generation Toolkit (para realizar reportes y guardar datos de la aplicación). ABSTRACT This project, called “Characterization of collectors for concentration photovoltaic systems”, consists in a Labview application to obtain the characteristics of the optical elements used in photovoltaic concentrator, taking into account the spatial distribution of concentrated light source generated. A concentrator photovoltaic system uses an optical system to transmit light radiation to the solar cell by increasing the light power density. This optical system are formed by mirrors or lenses to collect the radiation incident on them and focus the beam of light in a much smaller surface area. In this way you can reduce the area of semiconductor material needed, which implies a significant reduction in system cost. There are different concentration systems depending on the optics used, receptor structure or concentration range. However, as the aim is to analyze the spatial distribution, distinguish between two types of concentrators depending on the geometry that has the light focus. The linear or cylindrical concentrator that focused on a line, and the circular concentrator that focused light onto a point. Because this difference in both cases the analysis will be carried out differently. The analysis is performed by processing a focus image taken at the receiver site, this method is called “LS-CCD” (Light Scattering and CCD recording). Can be used in several mountings depending on whether the image is captured by reflection or transmission on the receiver. In some mountings it is not possible to capture the image perpendicular to the receivers so that the application makes an adjustment of perspective to get the focus to its original shape. The focus image provides detail information about the uniformity of focus through the surface map, which is a 3D image representation but it is unwieldy. A simple and useful representation is provided by so called “intensity profiles”. The intensity profile or irradiance distribution which represents the distribution of light to each distance to the center. The accumulated profile or accumulated irradiance that represents the cumulative light contained in relation also to the center. The representation of these profiles in the case of a linear and a circular concentrator are different due to their distinct geometry. While for a line focus profile is expressed in terms of semi-width of the receiver, for a circular concentrator is expressed in terms of radius. In either case provides information about the uniformity and size of focus needed to design the receiver. The objective of this project is the creation of a software application to perform processing and analysis of images obtained from light source of optical systems to characterize.The application has a simple and a intuitive interface so it can be used for any users. The resources required for the project are: a PC with Windows operating system, LabVIEW 8.6 Professional Edition and the modules NI Vision Development Module (for working with images) and NI Report Generation Toolkit (for reports and store application data .)