247 research outputs found

    Impact of operation strategies of large scale battery systems on distribution grid planning in Germany

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    Due to the increasing penetration of fluctuating distributed generation electrical grids require reinforcement, in order to secure a grid operation in accordance with given technical specifications. This grid reinforcement often leads to over-dimensioning of the distribution grids. Therefore, traditional and recent advances in distribution grid planning are analysed and possible alternative applications with large scale battery storage systems are reviewed. The review starts with an examination of possible revenue streams along the value chain of the German electricity market. The resulting operation strategies of the two most promising business cases are discussed in detail, and a project overview in which these strategies are applied is presented. Finally, the impact of the operation strategies are assessed with regard to distribution grid planning.Postprint (author's final draft

    Cluster analysis for phasing with molecular replacement: a feasibility study

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    Molecular replacement with the simultaneous use of several search functions may solve the phase problem when the conventional molecular-replacement procedure fails to identify the solution

    Towards the data-driven circular and embedded supply chain: Considerations from an ICT perspective

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    In the academic literature on Supply Chain Management the vision of a paradigm change from linear pipelines toward circular, postfossil, servitized and degrowth supply chains is drawn. Modern information and communication technologies are a key enabler for the realization of this vision. However, the literature remains vague on how these technologies can support the transformation. This publication aims to contribute to closing this gap. It provides an overview of relevant trends, technologies, and concepts, presents a visionary scenario for a data-driven and platform-based circular SCM, and identifies essential steps for its realization. Methodologically, the study is based on a literature review and a single case study in combination with an action research approach

    High resolution tumor targeting in living mice by means of multispectral optoacoustic tomography

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    BACKGROUND: Tumor targeting is of high clinical and biological relevance, and major efforts have been made to develop molecular imaging technologies for visualization of the disease markers in tissue. Of particular interest is apoptosis which has a profound role within tumor development and has significant effect on cancer malignancy. METHODS: Herein, we report on targeting of phosphatidylserine-exposing cells within live tumor allograft models using a synthetic near infrared zinc(II)-dipicolylamine probe. Visualization of the probe biodistribution is performed with whole body multispectral optoacoustic tomography (MSOT) system and subsequently compared to results attained by planar and tomographic fluorescence imaging systems. RESULTS: Compared to whole body optical visualization methods, MSOT attains remarkably better imaging capacity by delivering high-resolution scans of both disease morphology and molecular function in real time. Enhanced resolution of MSOT clearly showed that the probe mainly localizes in the vessels surrounding the tumor, suggesting that its tumor selectivity is gained by targeting the phosphatidylserine exposed on the surface of tumor vessels. CONCLUSIONS: The current study demonstrates the high potential of MSOT to broadly impact the fields of tumor diagnostics and preclinical drug development

    SpectroCube: a European 6U nanosatellite spectroscopy platform for astrobiology and astrochemistry

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    SpectroCube is a CubeSat-based miniaturized in-situ space exposure platform for astrochemistry and astrobiology research. Within a 6 unit (6U, with 1U corresponding to 10 cm x 10 cm x 10 cm) nanosatellite structure, an infrared spectrometer is interfaced with a sample handling system to measure photochemical changes of organic molecules, representing important biomarkers for the detection of life in our solar system and beyond. Monitoring degradation profiles and photochemical reaction kinetics of such biomarkers allows to identify suitable search targets for current and future planetary exploration and life-detection missions. SpectroCube is designed to be launched into a highly elliptical orbit around Earth and therefore allows to expose samples to higher solar UV and energetic particle radiation levels than previous exposure platforms in low Earth orbit, as for example on the International Space Station. In-situ data will be telemetered back to Earth and compared with solar and planetary simulation experiments in ground-based laboratory. We here present the design of SpectroCube, the scientific payload and its subsystems. We demonstrate that with the miniaturisation potential of infrared spectroscopy it is possible to fit the entire optical setup plus a sample handling system for up to 60 individually contained and hermetically sealed samples within less than half of the volume of a 6U CubeSat structure. Therefore, the remaining volume can be entirely used for additional subsystems such as attitude control, propulsion, fuel, onboard computer and telemetry. The design of the scientific payload is based on a commercial off-the-shelf miniaturised Fourier-transform spectrometer consisting of an infrared light source, an interferometer and infrared detector units. The mechanical robustness and suitability of such a system for space applications was assessed. Shock and vibration testing of the mechanically most sensitive unit, the interferometer, was performed and revealed that with adequate damping the spectroscopic performance can be maintained. Additional measurements of test samples conducted with the selected commercial off-the-shelf spectrometer candidate showed that the spectroscopic range, resolution and sensitivity is capable to monitor in situ the photochemical kinetics of important classes of organic molecules and biomarkers for astrobiology and astrochemistry research

    Development of a GEM-TPC prototype

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    The use of GEM foils for the amplification stage of a TPC instead of a con- ventional MWPC allows one to bypass the necessity of gating, as the backdrift is suppressed thanks to the asymmetric field configuration. This way, a novel continuously running TPC, which represents one option for the PANDA central tracker, can be realized. A medium sized prototype with a diameter of 300 mm and a length of 600 mm will be tested inside the FOPI spectrometer at GSI using a carbon or lithium beam at intermediate energies (E = 1-3AGeV). This detector test under realistic experimental conditions should allow us to verify the spatial resolution for single tracks and the reconstruction capability for displaced vertexes. A series of physics measurement implying pion beams is scheduled with the FOPI spectrometer together with the GEM-TPC as well.Comment: 5 pages, 4 figures, Proceedings for 11th ICATTP conference in como (italy

    Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe

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    The Extragalactic Background Light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the gamma-ray flux of extragalactic sources such as blazars and Gamma-Ray Bursts (GRBs). The Large Area Telescope onboard Fermi detects a sample of gamma-ray blazars with redshift up to z~3, and GRBs with redshift up to z~4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of gamma-ray flux attenuation by the EBL. We place upper limits on the gamma-ray opacity of the Universe at various energies and redshifts, and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. (2006) can be ruled out with high confidence.Comment: 42 pages, 12 figures, accepted version (24 Aug.2010) for publication in ApJ; Contact authors: A. Bouvier, A. Chen, S. Raino, S. Razzaque, A. Reimer, L.C. Reye
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