TY - JOUR A1 - Peere, Wouter A1 - Blanke, Tobias ED - Vernon, Chris T1 - GHEtool: An open-source tool for borefield sizing in Python JF - Journal of Open Source Software N2 - GHEtool is a Python package that contains all the functionalities needed to deal with borefield design. It is developed for both researchers and practitioners. The core of this package is the automated sizing of borefield under different conditions. The sizing of a borefield is typically slow due to the high complexity of the mathematical background. Because this tool has a lot of precalculated data, GHEtool can size a borefield in the order of tenths of milliseconds. This sizing typically takes the order of minutes. Therefore, this tool is suited for being implemented in typical workflows where iterations are required. GHEtool also comes with a graphical user interface (GUI). This GUI is prebuilt as an exe-file because this provides access to all the functionalities without coding. A setup to install the GUI at the user-defined place is also implemented and available at: https://www.mech.kuleuven.be/en/tme/research/thermal_systems/tools/ghetool. KW - geothermal KW - energy KW - borefields KW - sizing Y1 - 2022 U6 - https://doi.org/10.21105/joss.04406 SN - 2475-9066 VL - 7 IS - 76 SP - 1 EP - 4, 4406 ER - TY - BOOK A1 - Laack, Walter van T1 - Greater Than the Entire Universe Y1 - 2022 SN - 978-3-936624-52-6 PB - van Laack GmbH CY - Aachen ER - TY - CHAP A1 - Hoffschmidt, Bernhard A1 - Alexopoulos, Spiros A1 - Göttsche, Joachim A1 - Sauerborn, Markus A1 - Kaufhold, O. T1 - High Concentration Solar Collectors T2 - Comprehensive Renewable Energy (Second Edition) / Volume 3: Solar Thermal Systems: Components and Applications N2 - Solar thermal concentrated power is an emerging technology that provides clean electricity for the growing energy market. To the solar thermal concentrated power plant systems belong the parabolic trough, the Fresnel collector, the solar dish, and the central receiver system. For high-concentration solar collector systems, optical and thermal analysis is essential. There exist a number of measurement techniques and systems for the optical and thermal characterization of the efficiency of solar thermal concentrated systems. For each system, structure, components, and specific characteristics types are described. The chapter presents additionally an outline for the calculation of system performance and operation and maintenance topics. One main focus is set to the models of components and their construction details as well as different types on the market. In the later part of this article, different criteria for the choice of technology are analyzed in detail. KW - Central receiver system KW - Concentrated solar collector KW - Solar dish KW - Solar concentration Y1 - 2022 SN - 978-0-12-819734-9 U6 - https://doi.org/10.1016/B978-0-12-819727-1.00058-3 SP - 198 EP - 245 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Langohr, Philipp A1 - Bung, Daniel Bernhard A1 - Crookston, Brian M. ED - Ortega-Sánchez, Miguel T1 - Hybrid investigation of labyrinth weirs: Discharge capacity and energy dissipation T2 - Proceedings of the 39th IAHR World Congress N2 - The replacement of existing spillway crests or gates with labyrinth weirs is a proven techno-economical means to increase the discharge capacity when rehabilitating existing structures. However, additional information is needed regarding energy dissipation of such weirs, since due to the folded weir crest, a three-dimensional flow field is generated, yielding more complex overflow and energy dissipation processes. In this study, CFD simulations of labyrinth weirs were conducted 1) to analyze the discharge coefficients for different discharges to compare the Cd values to literature data and 2) to analyze and improve energy dissipation downstream of the structure. All tests were performed for a structure at laboratory scale with a height of approx. P = 30.5 cm, a ratio of the total crest length to the total width of 4.7, a sidewall angle of 10° and a quarter-round weir crest shape. Tested headwater ratios were 0.089 ≤ HT/P ≤ 0.817. For numerical simulations, FLOW-3D Hydro was employed, solving the RANS equations with use of finite-volume method and RNG k-ε turbulence closure. In terms of discharge capacity, results were compared to data from physical model tests performed at the Utah Water Research Laboratory (Utah State University), emphasizing higher discharge coefficients from CFD than from the physical model. For upstream heads, some discrepancy in the range of ± 1 cm between literature, CFD and physical model tests was identified with a discussion regarding differences included in the manuscript. For downstream energy dissipation, variable tailwater depths were considered to analyze the formation and sweep-out of a hydraulic jump. It was found that even for high discharges, relatively low downstream Froude numbers were obtained due to high energy dissipation involved by the three-dimensional flow between the sidewalls. The effects of some additional energy dissipation devices, e.g. baffle blocks or end sills, were also analyzed. End sills were found to be non-effective. However, baffle blocks with different locations may improve energy dissipation downstream of labyrinth weirs. Y1 - 2022 SN - 978-90-832612-1-8 U6 - https://doi.org/10.3850/IAHR-39WC252171192022738 SN - 2521-7119 (print) SN - 2521-716X (online) N1 - 39th IAHR World Congress, 19. - 24. Juni 2022, Granada SP - 2313 EP - 2318 PB - International Association for Hydro-Environment Engineering and Research (IAHR) CY - Madrid ER - TY - JOUR A1 - Rübbelke, Dirk A1 - Vögele, Stefan A1 - Grajewski, Matthias A1 - Zobel, Luzy T1 - Hydrogen-based steel production and global climate protection: An empirical analysis of the potential role of a European cross border adjustment mechanism JF - Journal of Cleaner Production N2 - The European Union's aim to become climate neutral by 2050 necessitates ambitious efforts to reduce carbon emissions. Large reductions can be attained particularly in energy intensive sectors like iron and steel. In order to prevent the relocation of such industries outside the EU in the course of tightening environmental regulations, the establishment of a climate club jointly with other large emitters and alternatively the unilateral implementation of an international cross-border carbon tax mechanism are proposed. This article focuses on the latter option choosing the steel sector as an example. In particular, we investigate the financial conditions under which a European cross border mechanism is capable to protect hydrogen-based steel production routes employed in Europe against more polluting competition from abroad. By using a floor price model, we assess the competitiveness of different steel production routes in selected countries. We evaluate the climate friendliness of steel production on the basis of specific GHG emissions. In addition, we utilize an input-output price model. It enables us to assess impacts of rising cost of steel production on commodities using steel as intermediates. Our results raise concerns that a cross-border tax mechanism will not suffice to bring about competitiveness of hydrogen-based steel production in Europe because the cost tends to remain higher than the cost of steel production in e.g. China. Steel is a classic example for a good used mainly as intermediate for other products. Therefore, a cross-border tax mechanism for steel will increase the price of products produced in the EU that require steel as an input. This can in turn adversely affect competitiveness of these sectors. Hence, the effects of higher steel costs on European exports should be borne in mind and could require the cross-border adjustment mechanism to also subsidize exports. Y1 - 2022 U6 - https://doi.org/10.1016/j.jclepro.2022.135040 SN - 0959-6526 VL - 380 IS - Part 2, Art. Nr.:135040 PB - Elsevier ER - TY - JOUR A1 - Werfel, Stanislas A1 - Günthner, Roman A1 - Hapfelmeier, Alexander A1 - Hanssen, Henner A1 - Kotliar, Konstantin A1 - Heemann, Uwe A1 - Schmaderer, Christoph ED - Guzik, Tomasz J. T1 - Identification of cardiovascular high-risk groups from dynamic retinal vessel signals using untargeted machine learning JF - Cardiovascular Research N2 - Dynamic retinal vessel analysis (DVA) provides a non-invasive way to assess microvascular function in patients and potentially to improve predictions of individual cardiovascular (CV) risk. The aim of our study was to use untargeted machine learning on DVA in order to improve CV mortality prediction and identify corresponding response alterations. KW - Machine learning KW - Retinal vessels KW - Microcirculation KW - Haemodialysis KW - Myocardial infarction and cardiac death Y1 - 2022 U6 - https://doi.org/10.1093/cvr/cvab040 SN - 0008-6363 VL - 118 IS - 2 SP - 612 EP - 621 PB - Oxford University Press CY - Oxford ER - TY - JOUR A1 - Philipp, Mohr A1 - Efthimiou, Nikos A1 - Pagano, Fiammetta A1 - Kratochwil, Nicolaus A1 - Pizzichemi, Marco A1 - Tsoumpas, Charalampos A1 - Auffray, Etiennette A1 - Ziemons, Karl T1 - Image reconstruction analysis for positron emission tomography with heterostructured scintillators JF - IEEE Transactions on Radiation and Plasma Medical Sciences N2 - The concept of structure engineering has been proposed for exploring the next generation of radiation detectors with improved performance. A TOF-PET geometry with heterostructured scintillators with a pixel size of 3.0×3.1×15 mm3 was simulated using Monte Carlo. The heterostructures consisted of alternating layers of BGO as a dense material with high stopping power and plastic (EJ232) as a fast light emitter. The detector time resolution was calculated as a function of the deposited and shared energy in both materials on an event-by-event basis. While sensitivity was reduced to 32% for 100 μm thick plastic layers and 52% for 50 μm, the CTR distribution improved to 204±49 ps and 220±41 ps respectively, compared to 276 ps that we considered for bulk BGO. The complex distribution of timing resolutions was accounted for in the reconstruction. We divided the events into three groups based on their CTR and modeled them with different Gaussian TOF kernels. On a NEMA IQ phantom, the heterostructures had better contrast recovery in early iterations. On the other hand, BGO achieved a better contrast to noise ratio (CNR) after the 15th iteration due to the higher sensitivity. The developed simulation and reconstruction methods constitute new tools for evaluating different detector designs with complex time responses. KW - TOF PET KW - Heterostructure KW - Metascintillator KW - Multiple TOF kernels KW - Image Reconstruction Y1 - 2022 U6 - https://doi.org/10.1109/TRPMS.2022.3208615 SN - 2469-7311 SN - 2469-7303 VL - 7 IS - 1 SP - 41 EP - 51 PB - IEEE CY - New York, NY ER - TY - CHAP A1 - Schwager, Christian A1 - Angele, Florian A1 - Nouri, Bijan A1 - Schwarzbözl, Peter A1 - Teixeira Boura, Cristiano José A1 - Herrmann, Ulf T1 - Impact of DNI forecast quality on performance prediction for a commercial scale solar tower: Application of nowcasting DNI maps to dynamic solar tower simulation T2 - SolarPACES 2022 conference proceedings N2 - Concerning current efforts to improve operational efficiency and to lower overall costs of concentrating solar power (CSP) plants with prediction-based algorithms, this study investigates the quality and uncertainty of nowcasting data regarding the implications for process predictions. DNI (direct normal irradiation) maps from an all-sky imager-based nowcasting system are applied to a dynamic prediction model coupled with ray tracing. The results underline the need for high-resolution DNI maps in order to predict net yield and receiver outlet temperature realistically. Furthermore, based on a statistical uncertainty analysis, a correlation is developed, which allows for predicting the uncertainty of the net power prediction based on the corresponding DNI forecast uncertainty. However, the study reveals significant prediction errors and the demand for further improvement in the accuracy at which local shadings are forecasted. KW - Process prediction KW - DNI forecasting KW - Nowcasting KW - Uncertainty analysis KW - Molten salt receiver system, Y1 - 2024 U6 - https://doi.org/10.52825/solarpaces.v1i.675 SN - 2751-9899 (online) N1 - SolarPACES 2022, 28th International Conference on Concentrating Solar Power and Chemical Energy Systems, 27-30 September, Albuquerque, NM, USA IS - 1 PB - TIB Open Publishing CY - Hannover ER - TY - JOUR A1 - Lenz, Maximilian A1 - Kahmann, Stephanie Lucina A1 - Behbahani, Mehdi A1 - Pennig, Lenhard A1 - Hackl, Michael A1 - Leschinger, Tim A1 - Müller, Lars Peter A1 - Wegmann, Kilian T1 - Influence of rotator cuff preload on fracture configuration in proximal humerus fractures: a proof of concept for fracture simulation JF - Archives of Orthopaedic and Trauma Surgery N2 - Introduction In regard of surgical training, the reproducible simulation of life-like proximal humerus fractures in human cadaveric specimens is desirable. The aim of the present study was to develop a technique that allows simulation of realistic proximal humerus fractures and to analyse the influence of rotator cuff preload on the generated lesions in regards of fracture configuration. Materials and methods Ten cadaveric specimens (6 left, 4 right) were fractured using a custom-made drop-test bench, in two groups. Five specimens were fractured without rotator cuff preload, while the other five were fractured with the tendons of the rotator cuff preloaded with 2 kg each. The humeral shaft and the shortened scapula were potted. The humerus was positioned at 90° of abduction and 10° of internal rotation to simulate a fall on the elevated arm. In two specimens of each group, the emergence of the fractures was documented with high-speed video imaging. Pre-fracture radiographs were taken to evaluate the deltoid-tuberosity index as a measure of bone density. Post-fracture X-rays and CT scans were performed to define the exact fracture configurations. Neer’s classification was used to analyse the fractures. Results In all ten cadaveric specimens life-like proximal humerus fractures were achieved. Two III-part and three IV-part fractures resulted in each group. The preloading of the rotator cuff muscles had no further influence on the fracture configuration. High-speed videos of the fracture simulation revealed identical fracture mechanisms for both groups. We observed a two-step fracture mechanism, with initial impaction of the head segment against the glenoid followed by fracturing of the head and the tuberosities and then with further impaction of the shaft against the acromion, which lead to separation of the tuberosities. Conclusion A high energetic axial impulse can reliably induce realistic proximal humerus fractures in cadaveric specimens. The preload of the rotator cuff muscles had no influence on initial fracture configuration. Therefore, fracture simulation in the proximal humerus is less elaborate. Using the presented technique, pre-fractured specimens are available for real-life surgical education. KW - Proximal humerus fracture KW - Biomechanical simulation KW - Fracture configuration KW - Fracture simulation KW - Rotator cuff Y1 - 2022 U6 - https://doi.org/10.1007/s00402-022-04471-9 SN - 1434-3916 PB - Springer CY - Berlin, Heidelberg ER - TY - JOUR A1 - Hein, Andreas M. A1 - Eubanks, T. Marshall A1 - Lingam, Manasvi A1 - Hibberd, Adam A1 - Fries, Dan A1 - Schneider, Jean A1 - Kervella, Pierre A1 - Kennedy, Robert A1 - Perakis, Nikolaos A1 - Dachwald, Bernd T1 - Interstellar now! Missions to explore nearby interstellar objects JF - Advances in Space Research N2 - The recently discovered first hyperbolic objects passing through the Solar System, 1I/’Oumuamua and 2I/Borisov, have raised the question about near term missions to Interstellar Objects. In situ spacecraft exploration of these objects will allow the direct determination of both their structure and their chemical and isotopic composition, enabling an entirely new way of studying small bodies from outside our solar system. In this paper, we map various Interstellar Object classes to mission types, demonstrating that missions to a range of Interstellar Object classes are feasible, using existing or near-term technology. We describe flyby, rendezvous and sample return missions to interstellar objects, showing various ways to explore these bodies characterizing their surface, dynamics, structure and composition. Their direct exploration will constrain their formation and history, situating them within the dynamical and chemical evolution of the Galaxy. These mission types also provide the opportunity to explore solar system bodies and perform measurements in the far outer solar system. KW - Interstellar objects KW - Trajectories KW - Missions Y1 - 2022 U6 - https://doi.org/10.1016/j.asr.2021.06.052 SN - 0273-1177 VL - 69 IS - 1 SP - 402 EP - 414 PB - Elsevier CY - Amsterdam ER -