1. |
- Kreuzig, C., et al.
(author)
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The CoPhyLab comet-simulation chamber
- 2021
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In: Review of Scientific Instruments. - : American Institute of Physics (AIP). - 0034-6748 .- 1089-7623. ; 92:11, s. 115102-115102
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Journal article (peer-reviewed)abstract
- The Comet Physics Laboratory (CoPhyLab) is an international research program to study the physical properties of cometary analog materials under simulated space conditions. The project is dedicated to studying, with the help of multiple instruments and the different expertise and background from the different partners, the physics of comets, including the processes inside cometary nuclei, the activity leading to the ejection of dust and gas, and the sub-surface and surface evolution of cometary nuclei when exposed to solar illumination. CoPhyLab will provide essential information on the formation and evolution of comets and insights into the origins of primitive Solar System bodies. To this end, we constructed a new laboratory that hosts several small-scale experiments and a large-scale comet-simulation chamber (L-Chamber). This chamber has been designed and constructed to host ice–dust samples with a diameter of up to 250 mm and a variable height between 100 and 300 mm. The cometary-analog samples will be kept at temperatures below 120 K and pressures around 10−6 mbar to ensure cometary-like conditions. In total, 14 different scientific instruments are attached to the L-Chamber to study the temporal evolution of the physical properties of the sample under different insolation conditions. Due to the implementation of a scale inside the L-Chamber that can measure weight changes of the samples with high precision, the cooling system is mechanically decoupled from the sample holder and cooling of the samples occurs by radiation only. The constructed chamber allows us to conduct uninterrupted experiments at low temperatures and pressures up to several weeks.
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2. |
- Lethuillier, A., et al.
(author)
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Cometary dust analogues for physics experiments
- 2022
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In: Monthly notices of the Royal Astronomical Society. - : Oxford University Press. - 0035-8711 .- 1365-2966. ; 515:3, s. 3420-3438
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Journal article (peer-reviewed)abstract
- The CoPhyLab (Cometary Physics Laboratory) project is designed to study the physics of comets through a series of earth-based experiments. For these experiments, a dust analogue was created with physical properties comparable to those of the non-volatile dust found on comets. This ‘CoPhyLab dust’ is planned to be mixed with water and CO2 ice and placed under cometary conditions in vacuum chambers to study the physical processes taking place on the nuclei of comets. In order to develop this dust analogue, we mixed two components representative for the non-volatile materials present in cometary nuclei. We chose silica dust as a representative for the mineral phase and charcoal for the organic phase, which also acts as a darkening agent. In this paper, we provide an overview of known cometary analogues before presenting measurements of eight physical properties of different mixtures of the two materials and a comparison of these measurements with known cometary values. The physical properties of interest are particle size, density, gas permeability, spectrophotometry, and mechanical, thermal, and electrical properties. We found that the analogue dust that matches the highest number of physical properties of cometary materials consists of a mixture of either 60 per cent/40 per cent or 70 per cent/30 per cent of silica dust/charcoal by mass. These best-fit dust analogue will be used in future CoPhyLab experiments.
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3. |
- Werdan, K., et al.
(author)
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Curriculum Kardiologie 2., aktualisierte Auflage
- 2020
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In: KARDIOLOGE. - : SPRINGER HEIDELBERG. - 1864-9718 .- 1864-9726. ; 14:6, s. 505-536
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Journal article (peer-reviewed)abstract
- The updated second edition of the "Curriculum cardiology", first edition 2013, aims to show which competences a cardiologist should nowadays master. It is very pleasing that in this second edition representatives of the Young German Cardiac Society (Young DGK) have contributed as authors. The increasing specialization within cardiology should, however, only represent one side of the coin: there must also still be a common foundation of cardiology, embedded in the discipline "internal medicine". This foundation includes the basis of theoretical knowledge, practical skills (competence levels I-III) and an occupational and professional attitude of the (prospective) cardiologist. New additions to the advanced training since the first edition of the curriculum in 2013 are, for example a chapter on digital cardiology, the further training in psychocardiology, which was newly introduced into the model further training regulations and finally also the explicit formulation of shared decision making in the interests of cardiac patients. The curriculum should give the prospective cardiologist the possibility to structure the further training as efficiently as possible and ultimately to retain and expand that which has been learned in the sense of a "professional lifelong" qualification. The curriculum also aims to reach the trainers and the Medical Councils and demonstrate which contents and skills should be mediated in the further training to become a cardiologist from the perspective of the German Cardiac Society (DGK).
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4. |
- Rahmati, Omid, et al.
(author)
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Capability and robustness of novel hybridized models used for drought hazard modeling in southeast Queensland, Australia
- 2020
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 718
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Journal article (peer-reviewed)abstract
- Widespread detrimental and long-lasting droughts are having catastrophic impacts around the globe. Researchers, organizations, and policy makers need to work together to obtain precise information, enabling timely and accurate decision making to mitigate drought impacts. In this study, a spatial modeling approach based on an adaptive neuro-fuzzy inference system (ANFIS) and several metaheuristic optimizations (ANFIS-BA, ANFIS-GA, ANFIS-ICA, ANFIS-PSO) was developed to predict the spatial occurrence of drought in a region in southeastern Queensland, Australia. In this approach, data describing the distribution of eight drought-contributing factors were prepared for input into the models to serve as independent variables. Relative departures of rainfall (RDR) and relative departures of soil moisture (RDSM) were analyzed to identify locations where drought conditions have occurred. The set of locations in the study area identified as having experienced drought conditions was randomly divided into two groups, 70% were used for training and 30% for validation. The models employed these data to generate maps that predict the locations that would be expected to experience drought. The prediction accuracy of the model-produced drought maps was scrutinized with two evaluation metrics: area under the receiver operating characteristic curve (AUC) and root mean square error (RMSE). The results demonstrate that the hybridized models (ANFIS-BA (AUC(mean) = 83.7%, RMSEmean = 0.236), ANFIS-GA (AUC(mean) = 81.62%, RMSEmean = 0.247), ANFIS-ICA (AUC(mean) = 82.12%, RMSEmean = 0.247), and ANFIS-PSO (AUC(mean) = 81.42%, RMSEmean = 0.255)) yield better predictive performance than the standalone ANFIS model (AUC(mean) = 71.8%, RMSEmean = 0.344). Furthermore, sensitivity analyses indicated that plantavailable water capacity, the percentage of soil comprised of sand, and mean annual precipitation were the most important predictors of drought hazard. The versatility of the new approach for spatial drought modeling and the capacity of ANFIS model hybridization to improve model performance suggests great potential to assist decision makers in their formulations of drought risk, recovery, and response management, and in the development of contingency plans.
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