1,304 research outputs found

    Synchrotron-based radioscopy employing spatio-temporal micro-resolution for studying fast phenomena in liquid metal foams

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    High-speed synchrotron-based radioscopy is applied to study a coalescence event (which lasts ∼2 ms) in situ in a liquid metal foam

    Reflection on multilayer mirrors beam profile and coherence properties

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    The main advantage of Bragg reflection from a multilayer mirror as a monochromator for hard X rays, is the higher photon flux density because of the larger spectral bandpass compared with crystal lattice reflection. The main disadvantage lies in the strong modulations of the reflected beam profile. This is a major issue for micro imaging applications, where multilayer based monochromators are frequently employed to deliver high photon flux density. A subject of particular interest is the origin of the beam profile modifications, namely the irregular stripe patterns, induced by the reflection on a multilayer. For multilayer coatings in general it is known that the substrate and its surface quality significantly influence the performance of mirrors, as the coating reproduces to a certain degree the roughness and shape of the substrate. This proceedings article reviews recent experiments that indicate potential options for producing wave front preserving multilayer mirrors, as well as new details on the particular mirrors our group has extensively studied in the pas

    The rupture of a single liquid aluminium alloy film

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    Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The present study is based on the idea of understanding the rupture of films in metal foams by studying free standing metallic films as a model system. Liquid dynamics, the velocity of the rupturing material as well as the behaviour of ceramic particles inside the melt were analysed optically ex situ and by synchrotron X-ray radiography in situ. It was found that the resistance of films to rupture is mainly based on the interaction between solid particles and an immobile oxide skin, the formation of which depends on the oxygen content of the surrounding atmosphere and the presence of magnesium

    Híbridos e variedades de milho submetidos à inoculação de sementes com Herbaspirillum seropedicae.

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    Resumo: A fixação biológica de nitrogênio proporcionada por bactérias diazotróficas pode representar alternativa para a produção de milho em sistemas agrícolas mais sustentáveis ou de baixa utilização de insumos. Objetivando-se avaliar o crescimento, teor e acúmulo de nitrogênio em genótipos de milho, em função da inoculação das sementes com Herbaspirillum seropedicae, foi conduzido experimento em casa de vegetação avaliando-se 35 genótipos de milho híbridos simples, duplo, triplo e variedades. Para inoculação das sementes foi utilizado inoculante turfoso contendo a estirpe bacteriana de H. seropedicae (ZAE 94). Entre os genótipos comerciais de milho estudados, apenas nove híbridos apresentam ganhos de crescimento ou acúmulo de N com a inoculação das sementes com a estirpe Herbaspirillum seropedicae (ZAE 94). Há distinção de resposta entre cultivares de milho em termos de produção de biomassa e incremento de teor de N na parte aérea das plantas. Abstract: The biological nitrogen fixation provided by diazotrophic bacteria may represent an alternative to maize production in more sustainable agricultural systems or low use of technology. In order to evaluate the growth, content and accumulation of nitrogen in corn genotypes, depending on seed inoculation with Herbaspirillum seropedicae experiment was conducted in greenhouse evaluating 35 corn genotypes hybrid single, double, triple and varieties. For seed inoculation was used peat inoculant containing the bacterial strain of H. seropedicae (ZAE 94). Among the commercial corn genotypes studied, only nine hybrids show increase of growth or accumulation of N with the seed inoculation with Herbaspirillum seropedicae (ZAE 94). There is a distinction in response between maize cultivars in terms of biomass production and increase of N content in the shoots

    An early myeloma bone disease model in skeletally mature mice as a platform for biomaterial characterization of the extracellular matrix

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    Multiple myeloma (MM) bone disease is characterized by osteolytic bone tissue destruction resulting in bone pain, fractures, vertebral collapse, and spinal cord compression in patients. Upon initial diagnosis of MM, almost 80% of patients suffer from bone disease. Earlier diagnosis and intervention in MM bone disease would potentially improve treatment outcome and patient survival. New preclinical models are needed for developing novel diagnostic markers of bone structural changes as early as possible in the disease course. Here, we report a proof-of-concept, syngeneic, intrafemoral MOPC315.BM MM murine model in skeletally mature BALB/c mice for detection and characterization of very early changes in the extracellular matrix (ECM) of MM-injected animals. Bioluminescence imaging (BLI) in vivo confirmed myeloma engraftment in 100% of the animals with high osteoclast activity within 21 days after tumor cell inoculation. Early signs of aggressive bone turnover were observed on the outer bone surfaces by high-resolution microcomputed tomography (microCT). Synchrotron phase contrast-enhanced microcomputer tomography (PCE-CT) revealed very local microarchitecture differences highlighting numerous active sites of erosion and new bone at the micrometer scale. Correlative backscattered electron imaging (BSE) and confocal laser scanning microscopy allowed direct comparison of mineralized and nonmineralized matrix changes in the cortical bone. The osteocyte lacunar-canalicular network (OLCN) architecture was disorganized, and irregular-shaped osteocyte lacunae were observed in MM-injected bones after 21 days. Our model provides a potential platform to further evaluate pathological MM bone lesion development at the micro- and ultrastructural levels. These promising results make it possible to combine material science and pharmacological investigations that may improve early detection and treatment of MM bone disease

    57. DATA REPORT: GEOCHEMICAL ANALYSIS OF MULTIPLE PLANKTONIC FORAMINIFER SPECIES AT DISCRETE TIME INTERVALS

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    ABSTRACT Three trace elements (magnesium, strontium, and fluoride) and the stable isotopes of carbon and oxygen were measured for three distinct samples (two from the middle Miocene and one from the late Oligocene) on numerous planktonic foraminiferal species. Foraminiferal calcite measured from Leg 144 preserves a heterogeneous range of trace element contents, implying that such measurements may have value as paleocean tracers for planktonic foraminifer paleoenvironments

    Inferring Private Personal Attributes of Virtual Reality Users from Head and Hand Motion Data

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    Motion tracking "telemetry" data lies at the core of nearly all modern virtual reality (VR) and metaverse experiences. While generally presumed innocuous, recent studies have demonstrated that motion data actually has the potential to uniquely identify VR users. In this study, we go a step further, showing that a variety of private user information can be inferred just by analyzing motion data recorded by VR devices. We conducted a large-scale survey of VR users (N=1,006) with dozens of questions ranging from background and demographics to behavioral patterns and health information. We then collected VR motion samples of each user playing the game ``Beat Saber,'' and attempted to infer their survey responses using just their head and hand motion patterns. Using simple machine learning models, many of these attributes could accurately and consistently be inferred from VR motion data alone, highlighting the pressing need for privacy-preserving mechanisms in multi-user VR applications

    Microporosity in aluminium foams

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    We studied microporosity in the metallic matrix of aluminium foams produced by the powder metallurgical route both with and without application of a blowing agent. Microporosity was studied in situ in liquid metal foams as well as ex situ in the solidified microstructures. In situ studies were carried out using synchrotron X rays. Quantitative analyses of the amount and distribution of microporosity inside cell walls, Plateau borders and nodes were performed on 2D micrographs and on 3D reconstructed volumes generated by X ray tomography. We studied the influence of alloying elements, blowing agent and holding time on the amount and type of micropores. The mechanisms of microporosity formation and the evolution of microporosity via diffusion of hydrogen and by coalescence are discussed. It was observed that alloy composition and holding time have a strong influence on microporosity. Different possible strategies to control microporosity are suggeste
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