850 research outputs found

    Strategie der schnittaufteilung. Еine wirksame methode zur leistungsanpassung und verbesserung des dynamischen schnittverhaltens beim planfräsen

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    Der Beitrag beinhaltet eine zusammenfassende Darstellung des Prinzips der Schnittaufteilung als Methode zur dynamischen Prozessstabilisierung beim Planfräsen. Es wird dargelegt, wie die Schnittaufteilung beim Fräsen durch die Kombination von WSP mit unterschiedlichen Formen prinzipiell realisiert werden kann. Neben der Erläuterung weiterer positiver Effekte wird auf die Nutzung der Schnittaufteilung zur Leistungsanpassung unter stabilen Bearbeitungsbedingungen eingegangen.В статті розглядається ефективний метод регулювання потужності фрезерування та покращення динамічних характеристик фрезерування. Запропоновано стратегію скорочення проходів

    Optimal consumption and investment with bounded downside risk for power utility functions

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    We investigate optimal consumption and investment problems for a Black-Scholes market under uniform restrictions on Value-at-Risk and Expected Shortfall. We formulate various utility maximization problems, which can be solved explicitly. We compare the optimal solutions in form of optimal value, optimal control and optimal wealth to analogous problems under additional uniform risk bounds. Our proofs are partly based on solutions to Hamilton-Jacobi-Bellman equations, and we prove a corresponding verification theorem. This work was supported by the European Science Foundation through the AMaMeF programme.Comment: 36 page

    Superantigen-Mediated Encephalitis

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    Climate change and the global pattern of moraine-dammed glacial lake outburst floods

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    This is the author accepted manuscript. The final version is available from EGU via the DOI in this recordThe published version, as published in The Cryosphere, is in ORE: http://hdl.handle.net/10871/32433Despite recent research identifying a clear anthropogenic impact on glacier recession, the effect of recent climate change on glacier-related hazards is at present unclear. Here we present the first global spatio-temporal assessment of glacial lake outburst floods (GLOFs) focusing explicitly on lake drainage following moraine dam failure. These floods occur as mountain glaciers recede and downwaste and many have an enormous impact on downstream communities and infrastructure. Our assessment of GLOFs associated with the collapse of moraine-dammed lakes provides insights into the historical trends of GLOFs and their distributions under current and future global climate change. We observe a clear global increase in GLOF frequency and their regularity around 1930, which likely represents a lagged response to post-Little Ice Age warming. Notably, we also show that GLOF frequency and their regularity – rather unexpectedly – has declined in recent decades even during a time of rapid glacier recession. Although previous studies have suggested that GLOFs will increase in response to climate warming and glacier recession, our global results demonstrate that this has not yet clearly happened. From assessment of the timing of climate forcing, lag times in glacier recession, lake formation and moraine dam failure, we predict increased GLOF frequencies during the next decades and into the 22nd century.SH was funded by a Leverhulme Research Fellowship. SH, RAB and AW acknowledge funding under the HELIX (European Union Seventh Framework Programme FP7/2007-2013 under grant agreement n° 603864). AW and RAB acknowledge funding from the Joint UK DECC/Defra Met Office Hadley Centre Climate Programme (GA01101)

    Optoelectronic analysis of multijunction wire array solar cells

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    Wire arrays have demonstrated promising photovoltaic performance as single junction solar cells and are well suited to defect mitigation in heteroepitaxy. These attributes can combine in tandem wire array solar cells, potentially leading to high efficiencies. Here, we demonstrate initial growths of GaAs on Si_(0.9)Ge_(0.1) structures and investigate III-V on Si_(1-x)Ge_x device design with an analytical model and optoelectronic simulations. We consider Si_(0.1)Ge_(0.9) wires coated with a GaAs_(0.9)P_(0.1) shell in three different geometries: conformal, hemispherical, and spherical. The analytical model indicates that efficiencies approaching 34% are achievable with high quality materials. Full field electromagnetic simulations serve to elucidate the optical loss mechanisms and demonstrate light guiding into the wire core. Simulated current-voltage curves under solar illumination reveal the impact of a varying GaAs_(0.9)P_(0.1) minority carrier lifetime. Finally, defective regions at the hetero-interface are shown to have a negligible effect on device performance if highly doped so as to serve as a back surface field. Overall, the growths and the model demonstrate the feasibility of the proposed geometries and can be used to guide tandem wire array solar cell designs

    Effects of light at night on laboratory animals and research outcomes

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    Light has substantial influences on the physiology and behavior of most laboratory animals. As such, lighting conditions within animal rooms are potentially significant, and often underappreciated variables within experiments. Disruption of the light/dark cycle, primarily by exposing animals to light at night (LAN), disturbs biological rhythms and has widespread physiological consequences due to mechanisms such as melatonin suppression, sympathetic stimulation, and altered circadian clock gene expression. Thus, attention to the lighting environment of laboratory animals and maintaining consistency of a light/dark cycle is imperative for study reproducibility. Light intensity as well as wavelength, photoperiod, and timing are all important variables. Although modern rodent facilities are designed to facilitate appropriate light cycling, there are simple ways to modify rooms to prevent extraneous light exposure during the dark period. Attention to lighting conditions of laboratory animals by both researchers and research care staff ensures best practices for maintaining animal welfare, as well as reproducibility of research results

    Effectively Transparent Front Contacts for Optoelectronic Devices

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    Effectively transparent front contacts for optoelectronic devices achieve a measured transparency of up to 99.9% and a measured sheet resistance of 4.8 Ω sq^(−1). The 3D microscale triangular cross-section grid fingers redirect incoming photons efficiently to the active semiconductor area and can replace standard grid fingers as well as transparent conductive oxide layers in optoelectronic devices
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