657 research outputs found

    Atmospheric energy spectra in global kilometre-scale models

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    Eleven 40-day long integrations of five different global models with horizontal resolutions of less than 9 km are compared in terms of their global energy spectra. The method of normal-mode function decomposition is used to distinguish between balanced (Rossby wave; RW) and unbalanced (inertia-gravity wave; IGW) circulation. The simulations produce the expected canonical shape of the spectra, but their spectral slopes at mesoscales, and the zonal scale at which RW and IGW spectra intersect differ significantly. The partitioning of total wave energies into RWs an IGWs is most sensitive to the turbulence closure scheme and this partitioning is what determines the spectral crossing scale in the simulations, which differs by a factor of up to two. It implies that care must be taken when using simple spatial filtering to compare gravity wave phenomena in storm-resolving simulations, even when the model horizontal resolutions are similar. In contrast to the energy partitioning between the RWs and IGWs, changes in turbulence closure schemes do not seem to strongly affect spectral slopes, which only exhibit major differences at mesoscales. Despite their minor contribution to the global (horizontal kinetic plus potential available) energy, small scales are important for driving the global mean circulation. Our results support the conclusions of previous studies that the strength of convection is a relevant factor for explaining discrepancies in the energies at small scales. The models studied here produce the major large-scale features of tropical precipitation patterns. However, particularly at large horizontal wavenumbers, the spectra of upper tropospheric vertical velocity, which is a good indicator for the strength of deep convection, differ by factors of three or more in energy. High vertical kinetic energies at small scales are mostly found in those models that do not use any convective parameterisation

    Investigation and Assessment of Resource Consumption of Process Chains

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    AbstractMany different technologies and processes have been established in production within the last decades. These technologies have to be integrated into sophisticated process chains to achieve today's requirements of high performance products. For most of these products the costs can be determined or at least estimated accurately. However, resource intensive and thus cost intensive processes and their potential within the process chains are often neither identified nor quantified. For identifying, measuring and subsequently assessing the need of resources, like energy or material and their monetary as well as environmental impact, four different process chains of high industrial relevance have been chosen and investigated with regards to their resource consumption. These process chains are used for manufacturing turbine blades made of Inconel and titanium aluminide as well as for comparisons of a conventional and an innovative process chain to manufacture an insert for an injection mold. By measuring and assessing their resource consumption the most resource intensive and thus influential processes have been identified and their potential for resource reduction has been evaluated. Due to the change of single processes to reduce resource consumption and thus the conditions for subsequent processes, the requirements might change and lead to adaptions within the entire process chain. For the assessment of the process chains and the changes within the processes themselves, a scenario based assessment has been modelled. This results in an economic and ecologic evaluation of these process chains and enables a comparison of these to choose the most meaningful process chain

    Investigation on the International State of the Art of Micro Production Technology

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    The study “microPRO” dealing with the international state of the art of micro production technology was conducted by the above named Institutes. The objective of this study was to determine the worldwide state-of-the-art technology and research in micro production technology by means of scientific investigations and technical discussions with the technology leaders and, based on this, to identify the required research and development as well as the future potentials of these technologies in view of the market-overlapping economic utilization of miniaturized products

    The art and science of climate model tuning

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    PublishedThis is the final version of the article. Available from American Meteorological Society via the DOI in this record.We survey the rationale and diversity of approaches for tuning, a fundamental aspect of climate modeling which should be more systematically documented and taken into account in multi-model analysis. The process of parameter estimation targeting a chosen set of observations is an essential aspect of numerical modeling. This process is usually named tuning in the climate modeling community. In climate models, the variety and complexity of physical processes involved, and their interplay through a wide range of spatial and temporal scales, must be summarized in a series of approximate sub-models. Most sub-models depend on uncertain parameters. Tuning consists of adjusting the values of these parameters to bring the solution as a whole into line with aspects of the observed climate. Tuning is an essential aspect of climate modeling with its own scientific issues, which is probably not advertised enough outside the community of model developers. Optimization of climate models raises important questions about whether tuning methods a priori constrain the model results in unintended ways that would affect our confidence in climate projections. Here we present the definition and rationale behind model tuning, review specific methodological aspects, and survey the diversity of tuning approaches used in current climate models. We also discuss the challenges and opportunities in applying so-called ‘objective‘ methods in climate model tuning. We discuss how tuning methodologies may affect fundamental results of climate models, such as climate sensitivity. The article concludes with a series of recommendations to make the process of climate model tuning more transparent.The authors would like to thank the World Climate Research Program and its Working Group on Coupled Modeling for initiating and helping organize the workshop on model tuning in October 2014 in Garmisch-Partenkirchen, Germany. Work at LLNL was performed under the auspices the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract No. DE-AC52-07NA27344. The National Center for Atmospheric Research is sup- ported by the U.S. National Science Foundation. The contribution of Yun Qian was supported by the U.S. Department of Energy’s Office of Science as part of the Earth System Modeling Program. The Pacific Northwest National Laboratory is operated for DOE by Battelle Memorial Institute under contract DE-AC05-76RL0183

    Erarbeitung betriebsindividueller Handlungsempfehlungen zur Verbesserung der Euter- und Stoffwechselgesundheit im Rahmen einer interdisziplinären Interventionsstudie

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    Kernziel des im Rahmen des Bundesprogramms Ökologischer Landbau initiierten Forschungsvorhabens „Gesundheit und Leistungsfähigkeit von Milchkühen im ökologischen Landbau interdisziplinär betrachtet“ (FKZ 07OE012 - 07OE022) ist - neben der Abschätzung des Risikos für Stoffwechselstörungen und Eutererkrankungen - die Entwicklung eines praxistauglichen, präventiv orientierten Tiergesundheitsmanagements für die Praxis der ökologischen Milchviehhaltung. Basierend auf einer Interventionsstudie auf 106 repräsentativ ausgewählten Milchviehbetrieben soll dieses Managementkonzept in einer zweijährigen Praxisphase validiert und auf seine Praxistauglichkeit überprüft werden. Als Grundlage für die Identifikation einzelbetrieblicher Interventionsmaßnahmen dienen zentrale Indikatoren der Euter- und Stoffwechselgesundheit, deren Abgleich mit im Vorfeld definierten Zielgrößen sowie Informationen zur Haltungsumwelt und zum Herdenmanagement. Das entwickelte Konzept soll eine einzelbetriebliche Einschätzung des Gesundheitsstatus der Milchviehherde bezüglich der Euter- und Stoffwechselgesundheit ermöglichen, auf deren Basis Handlungsempfehlungen zur nachhaltigen Verbesserung der Milchviehgesundheit abgeleitet werden können. Die Projektbetriebe setzten zwei Drittel der empfohlenen Maßnahmen um; eine abschließende Effektivitätskontrolle in Bezug auf die Verbesserung der Euter- und Stoffwechselgesundheit auf den Betrieben auf Basis der Daten des letzten Projektjahres steht noch aus

    Миграция и эмиграция поволжских немцев

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    This article presents an overview of current simulation methods describing the interaction of grinding process and grinding machine structure, e.g., vibrations, deflections, or thermal deformations. Innovative process models which describe the effects of the grinding wheel–workpiece interaction inside the contact zone are shown in detail. Furthermore, simulation models representing the static and dynamic behaviour of a grinding machine and its components are discussed. Machine tool components with a high influence on the process results are modelled more detailed than those with low influence. The key issue of the paper is the coupling of process and machine tool models for predicting the interactions of process and machine. Several coupling methods are introduced and the improvements of the simulation results are documented. On the basis of the presented simulation approaches, grinding processes and machines can be designed more effectively resulting in higher workpiece quality and process stability

    Gesundheit und Leistungsfähigkeit von Milchkühen im ökologischen Landbau interdisziplinär betrachtet – eine (Interventions-) Studie zu Stoffwechselstörungen und Eutererkrankungen unter Berücksichtigung von Grundfuttererzeugung, Fütterungsmanagement und Tierhaltung

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    Im Mittelpunkt des Projektes stand die Stoffwechsel- und Eutergesundheit von ökologisch gehaltenen Milchkühen im prä- und peripartalen Zeitraum sowie in den ersten 100 Laktationstagen und deren Beeinflussung durch die Futter- und Nährstoffversorgung und die Haltungsumwelt im umfassenden Sinn. In einer bundesweiten Feldstudie auf 106 ökologisch wirtschaftenden Milchviehbetrieben erfolgten Erhebungen mit dem Ziel einer Risikomodellierung zu Stoffwechsel- und Eutererkrankungen. Vor diesem Hintergrund wurden die Produktionssysteme von der Pflanzenzusammensetzung im Grünland und im Ackerfutter über die Grobfutterproduktion, Futterqualität und Rationsgestaltung, Haltungsumwelt bis hin zur Tiergesundheit und Milchqualität analysiert, um hier einzelbetriebliche Risikoeinschätzungen vorzunehmen, Optimierungspotenziale aufzuzeigen und Handlungsempfehlungen abzuleiten, die anschließend betriebsindividuell implementiert wurden. Die Effektivität des so geschaffenen präventiv orientierten Tiergesundheitsmanagements wurde anhand der Entwicklung ausgewählter Kennzahlen der Euter- und Stoffwechselgesundheit geprüft. Es konnte gezeigt werden, dass sich mit dieser Vorgehensweise auch unter Praxisbedingungen die Tiergesundheitssituation signifikant verbes-sern lässt. Die Feldstudie wurde mit experimentellen Untersuchungen ergänzt, die sich speziellen Fragen der Analyse von nXP in Grasprodukten, des Kraftfuttereinsatzes, der Wahl der geeigneten Rasse, dem Infektionsgeschehen, der Nutzung von Haltungstechniken im Fütterungsmanagement und der Verbesserung der Grasnarbe widmeten. Die im Projekt generierten, aufgrund ihrer Ableitung aus der Praxis widerspruchsarmen Erkenntnisse wurden über vielfältige Formen des Wissenstransfers an die Akteure in der Ökologischen Milchviehhaltung vermittelt. Ein Merkblatt zur Euter- und Stoffwechselgesundheit bei Biomilchkühen und ein modular aufgebautes Wissenstransferkonzept wurden erarbeitet, um die Projektergebnisse nachhaltig nutzen zu können
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