Large-scale mass distribution in the Illustris simulation

Observations at low redshifts thus far fail to account for all of the baryons expected in the Universe according to cosmological constraints. A large fraction of the baryons presumably resides in a thin and warm-hot medium between the galaxies, where they are difficult to observe due to their low densities and high temperatures. Cosmological simulations of structure formation can be used to verify this picture and provide quantitative predictions for the distribution of mass in different large-scale structure components. Here we study the distribution of baryons and dark matter at different epochs using data from the Illustris simulation. We identify regions of different dark matter density with the primary constituents of large-scale structure, allowing us to measure mass and volume of haloes, filaments and voids. At redshift zero, we find that 49 % of the dark matter and 23 % of the baryons are within haloes more massive than the resolution limit of $2\times 10^8$ M$_\odot$. The filaments of the cosmic web host a further 45 % of the dark matter and 46 % of the baryons. The remaining 31 % of the baryons reside in voids. The majority of these baryons have been transported there through active galactic nuclei feedback. We note that the feedback model of Illustris is too strong for heavy haloes, therefore it is likely that we are overestimating this amount. Categorizing the baryons according to their density and temperature, we find that 17.8 % of them are in a condensed state, 21.6 % are present as cold, diffuse gas, and 53.9 % are found in the state of a warm-hot intergalactic medium.Comment: 12 pages, 15 figure

Lesetest für Berufsschüler/innen LTB-3. Handbuch

Klassenarbeiten, Klausuren und Fachprüfungen dauern oft mehrere Stunden,sowohl in ihrer Dauer wie in ihrer Auswertung. Die Dauer der Prüfungen ist in Prüfungsordnungen vorgegeben. Der vorliegende Test ermöglicht es, auf ökonomische und objektive Weise die Lesekompetenz von Schülerinnen und Schülern zu erfassen. Er ist einfach handzuhaben, Testdurchführung und -auswertung nehmen nur wenig Zeit in Anspruch und ermöglichen eine problemlose Integration in den Schulalltag. Ein Test kann nicht von einer Person entwickelt werden und so stehen als Autoren und Berater mehrere Personen auf der Titelseite. Neben den genannten Mitwirkenden waren noch unzählige Personen beteiligt, die hier und da konstruktiv an einer Frage „herumkritisierten“

Rings and Chains: Synthesis and Characterization of Polyferrocenylmethylene

The synthesis and characterization of polyferrocenylmethylene (PFM) starting from dilithium 2,2-bis(cyclopentadienide)propane and a Me2C[1]magnesocenophane is reported. Molecular weights of up to Mw = 11 700 g mol–1 featuring a dispersity, Ð, of 1.40 can be achieved. The material is studied by different methods comprising nuclear magnetic resonance (NMR) spectroscopy, matrix-assisted laser desorption/ionization time of flight (MALDI-ToF) mass spectrometry, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) measurements elucidating the molecular structure and thermal properties of these novel polymers. Moreover, cyclic voltammetry (CV) reveals quasi-reversible oxidation and reduction behavior and communication between the iron centers. Also, the crystal structure of a related cyclic hexamer is presented

Experimental evaluation of the CO2-based mixture CO2/C6F6 in a recuperated transcritical cycle

Zeotropic CO2-based mixtures as working fluids in the power block have the potential to enhance concentrated solar power (CSP) plants and other high-temperature heat source applications. One promising working fluid is the CO2/C6F6 mixture, which enables condensation at 50 °C – a necessity when dry cooling with ambient air. Given the many theoretical studies on topics such as potential, optimized performance, or economic assessments, an experimental validation and a reality-check in a facility of significant size is required to vindicate further research. The experimental campaign was performed on pure CO2 and the CO2/C6F6 mixture in two compositions in a test facility (recuperated transcritical cycle). The long-term test (170h) revealed no operational issues, including no signs of thermal degradation. However, a composition shift - an effect previously regarded as an issue in closed cycles with zeotropic mixtures - affected the conditions at the vapor-liquid-equilibrium in the systems tank but also self-stabilizes the system to remain condensing, even at higher ambient air temperatures. The successful proof-of-concept at cycle temperatures of up to 500 °C – significantly higher than earlier studies on mixtures reported (<300 °C) – justifies further research in this area

Dynamic Modeling and Analysis of a Disruptive Thermochemical Energy Storage Suitable for Linear Focus Solar Technologies

The industrial sector is a significant energy consumer, primarily reliant on fossil fuels. Nevertheless, the potential of Concentrated Solar Power (CSP) technologies for decarbonizing the industry is promising and the challenges posed by variability in weather and seasons can be effectively addressed through the use of seasonal storage methods, such as Thermochemical Energy Storage (TCES). This study presents a dynamic lumped-capacitance model, implemented in Dymola, designed to simulate a continuous suspension reactor employing salt hydrates like calcium oxalate monohydrate/anhydrous. The model mainly comprised (i) heat balances, (ii) reaction kinetics for the dehydration process and (iii) a heat transfer model. Furthermore, the study delves into a comprehensive case study involving the integration of CSP and TCES into a dairy processing facility located in Spain, addressing both daily operational requirements and seasonal energy storage demands. The solar field, heating demand, and storage tanks are described in detail. The transient simulation results for July showcase the efficacy of the solar installation and sensible energy storage for day-to-day operations, resulting in a total solar contribution of 47.3%. Notably, the thermochemical energy stored during this period can cover 22.1% of the low-temperature energy demand in January. The study underscores the importance of TCES in sustainable energy systems and paves the way for further optimization, economic assessment, and expanded applications. Future work will focus on enhancing the model and incorporating additional thermochemical materials, supported by additional experimental data

Dry-Cooled Rankine Cycle Operated With Binary Carbon Dioxide Based Working Fluids

The dry-cooled Rankine cycle working with a zeotropic mixture of CO2+C6F6 is influenced by the ambient temperature as air is used as the heat sink. Varying heat sink temperatures allow for operating the cycle under sliding condensation pressure which may benefit a hybrid PV-CSP plant. The study demonstrates the effect of this operation mode on composition shift and condensation pressure and investigates the cycle performance. The results show that defining the turbine design conditions significantly impact whether the system´s thermodynamic performance behaves acceptably in off-design conditions. Operating the turbine which was designed for a big pressure ratio in part-load especially if both, inlet and outlet pressure are at off-design conditions, is not favorable and leads to deteriorated efficiencies. Under some constraints for turbine and heat exchanger design, the proposed cycle enhances the hybrid PV-CSP system

Situational awareness within objective structured clinical examination stations in undergraduate medical training - a literature search

Background: Medical students may not be able to identify the essential elements of situational awareness (SA) necessary for clinical reasoning. Recent studies suggest that students have little insight into cognitive processing and SA in clinical scenarios. Objective Structured Clinical Examinations (OSCEs) could be used to assess certain elements of situational awareness. The purpose of this paper is to review the literature with a view to identifying whether levels of SA based on Endsley's model can be assessed utilising OSCEs during undergraduate medical training. Methods: A systematic search was performed pertaining to SA and OSCEs, to identify studies published between January 1975 (first paper describing an OSCE) and February 2017, in peer reviewed international journals published in English. PUBMED, EMBASE, PsycINFO Ovid and SCOPUS were searched for papers that described the assessment of SA using OSCEs among undergraduate medical students. Key search terms included "objective structured clinical examination", "objective structured clinical assessment" or "OSCE" and "non-technical skills", "sense-making", "clinical reasoning", "perception", "comprehension", "projection", "situation awareness", "situational awareness" and "situation assessment". Boolean operators (AND, OR) were used as conjunctions to narrow the search strategy, resulting in the limitation of papers relevant to the research interest. Areas of interest were elements of SA that can be assessed by these examinations. Results: The initial search of the literature retrieved 1127 publications. Upon removal of duplicates and papers relating to nursing, paramedical disciplines, pharmacy and veterinary education by title, abstract or full text, 11 articles were eligible for inclusion as related to the assessment of elements of SA in undergraduate medical students. Discussion: Review of the literature suggests that whole-task OSCEs enable the evaluation of SA associated with clinical reasoning skills. If they address the levels of SA, these OSCEs can provide supportive feedback and strengthen educational measures associated with higher diagnostic accuracy and reasoning abilities. Conclusion: Based on the findings, the early exposure of medical students to SA is recommended, utilising OSCEs to evaluate and facilitate SA in dynamic environment

The fundamental left-right asymmetry in the Germanic verb cluster

Cinque (2005, 2009, 2014a) observes that there is an asymmetry in the possible ordering of dependents of a lexical head before versus after the head. A reflection on some of the concepts needed to develop Cinque’s ideas into a theory of neutral word order reveals that dependents need to be treated separately by class. The resulting system is applied to the problem of word order in the Germanic verb cluster. It is shown that there is an extremely close match between theoretically derived expectations for clusters made up of auxiliaries, modals, causative ‘let’, a main verb, and verbal particles. The facts point to the action of Cinque’s fundamental left-right asymmetry in language in the realm of the verb cluster. At the same time, not all verb clusters fall under Cinque’s generalization, which, therefore, argues against treating all cases of restructuring uniformly