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A Critical Review and Assessment of Different Thermoviscoplastic Material Models for Simultaneous Hot/Cold Forging Analysis
(2020-05-26)
The simultaneous hot/cold forging is an innovative production process, taking advantage of the high accuracy for cold forming and low forces for hot forming. However, the choice of a suitable material model for such a large temperature range is a difficult issue and insufficiently regarded. Hence, the aim of this contribution is a critical review and assessment of the prediction capability and accuracy of three already existing thermo-viscoplasticity models. Therefore, the simulation results of the Bammann, Chiesa ...
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SimBench—A Benchmark Dataset of Electric Power Systems to Compare Innovative Solutions Based on Power Flow Analysis
(2020-06-26)
Publicly accessible, elaborated grid datasets, i.e., benchmark grids, are well suited to publish and compare methods or study results. Similarly, developing innovative tools and algorithms in the fields of grid planning and grid operation is based on grid datasets. Therefore, a general methodology to generate benchmark datasets and its voltage level dependent implementation is described in this paper. As a result, SimBench, a comprehensive dataset for the low, medium, high and extra-high voltage level, is presented. ...
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Experimentelle Untersuchung zur Mehrphasenströmung in öleingespritzten Mehrphasenschraubenspindelpumpen
(2020-02-18)
Für die Förderung von Gemischen mit hohen Gasanteilen erfolgt die Entwicklung eines neuen Kühlkonzepts, indem das Prozessfluid in flüssiger Phase extern in die Förderkammer einer Mehrphasenpumpe eingespritzt wird. Neben der Regulierung des Thermomanagements trägt dies zur Spaltabdichtung bei, so dass der effektiv geförderte Volumenstrom steigt. Zur Untersuchung der Thermo‐ und Fluiddynamik einer solchen Mehrphasenpumpe wird ein transparentes Förderkammermodell der Pumpe mit externer Fluideinspritzung entwickelt. Das ...
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Grain-Size Specific Characterisation and Resource Potentials of Municipal Solid Waste Incineration (MSWI) Bottom Ash: A German Case Study
(2020-05-31)
Municipal solid waste incineration (MSWI) is a major element of modern waste management and produces annually around 5.7 million tonnes of bottom ash (BA) in Germany. In order to save natural resources and protect the environment, utilisable materials need to be recovered from BA. It was the aim of the present study to determine metal and mineral resource potentials of MSWI BA based on a characterisation study of raw and aged BA of the MSWI plant in Kassel (Germany). The BA investigated consisted of 82.2% mineral ...
Aufsatz
Improving Vertical Wind Speed Extrapolation Using Short-Term Lidar Measurements
(2020-03-29)
This study investigates how short-term lidar measurements can be used in combination with a mast measurement to improve vertical extrapolation of wind speed. Several methods are developed and analyzed for their performance in estimating the mean wind speed, the wind speed distribution, and the energy yield of an idealized wind turbine at the target height of the extrapolation. These methods range from directly using the wind shear of the short-term measurement to a classification approach based on commonly available ...
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Comparison Between Two Hydrodynamic Models in Simulating Physical Processes of a Reservoir with Complex Morphology: Maroon Reservoir
(2020-03-14)
Two 3D hydrodynamic models, AEM3D and MIKE3, are compared in simulating hydrodynamics of the Maroon Reservoir in southwest Iran. The reservoir has a complex bathymetry with steep walls, which makes it a good case for studying the performance of hydrodynamic models. The models were compared together and with measured water temperatures from different locations of the reservoir in a five-month period between December 2011 and April 2012. The results indicated that the AEM3D model, which uses a finite difference scheme ...
Aufsatz
Wie können Systeme künstlicher Intelligenz ohne Qualitätsverlust rechtsverträglich gestaltet werden?
(2020-03-03)
Künstliche intelligente (KI)-Systeme erfreuen sich immer größerer Beliebtheit. Im Alltag erleben wir KI beispielsweise durch smarte persönliche Assistenten (SPAs), welche von Amazon, Google und Co. angeboten werden. Zwar haben diese KI-Systeme große Nutzungspotenziale, gleichzeitig gehen damit aber auch erhebliche Risiken einher, beispielsweise datenschutzrechtliche. Doch wie lassen sich diese Spannungsfelder auflösen? Interdisziplinäre Gestaltungsmuster im Systementwicklungsprozess können eine Lösung darstellen, ...
Aufsatz
First-Order Shape Derivative of the Energy for Elastic Plates with Rigid Inclusions and Interfacial Cracks
(2020-11-16)
Within the framework of Kirchhoff–Love plate theory, we analyze a variational model for elastic plates with rigid inclusions and interfacial cracks. The main feature of the model is a fully coupled nonpenetration condition that involves both the normal component of the longitudinal displacements and the normal derivative of the transverse deflection of the crack faces. Without making any artificial assumptions on the crack geometry and shape variation, we prove that the first-order shape derivative of the potential ...
Aufsatz
Renewable Energy Integration for Steam Supply of Industrial Processes—A Food Processing Case Study
(2020-05-16)
This study highlights the CO2,e -emission reduction potentials and related economic consequences for changing steam generation from fossil to renewable. Seven different utility concepts are developed, including a steam accumulator for load management. Peculiarities for the integration of biogas boilers, biomass-fuelled boilers, electrode steam boilers, biomethane-fuelled solid oxide fuel cells, micro gas turbine, solar energy systems, heat pumps and steam accumulators into a steam system with fluctuating steam demand ...
Aufsatz
Comparison between Hyperspectral Imaging and Chemical Analysis of Polyphenol Oxidase Activity on Fresh-Cut Apple Slices
(2020-06-29)
The assessment of the quality of fresh-cut apple slices is important for processing, storage, market value, and consumption. Determination of polyphenol oxidase activity (PPO) in apples is critical for controlling the quality of the final product (i.e., dried apples and juices). Hyperspectral imaging (HSI) is a nondestructive, noncontact, and rapid food quality assessment technique. It has the potential to detect physical and chemical quality attributes of foods such as PPO of apple. The aim of this study was to ...