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Kershaw, Ian: Der Mensch und die Macht. Über Erbauer und Zerstörer Europas im 20. Jahrhundert, übers. v. Klaus-Dieter Schmidt, 592 S., DVA, München 2022.
No full textDie deutsche Geschichtswissenschaft tut sich mit Biografien schwer – auch das ist ein Erbe der seit den 1950er Jahren erfolgten Abkehr von der Tradition. Lebensbeschreibungen sind zwar auch hierzulande oft Verkaufserfolge, aber innerhalb der Zunft verdient man sich damit im Regelfall keine Meriten. Besser gesagt: Man hat sie zumeist schon, wenn man in einer oft späten Phase seines Forscherlebens dieses Genre bedient. In den angelsächsischen Ländern, zumal in Großbritannien, ist das ganz anders. Dort wird das Publikum auch regelmäßig zur Abstimmung über die ‚größte‘ Persönlichkeit der britischen Geschichte, über „100 Greatest Britons“ (so die BBC 2002) gebeten. In Deutschland dagegen teilte das Nachschlagewerk „Die großen Deutschen“ nicht nur das Schicksal aller gedruckten Nachschlagewerke und verschwand vom Markt, sondern dokumentierte unfreiwillig auch noch den Konstruktionscharakter dieser Kategorie: In der ersten, von Willy Andreas herausgegebenen Auflage fehlte 1936 in Band 4 Gustav Stresemann als verhasster „Erfüllungspolitiker“, während Theodor Heuss dafür sorgte, dass Stresemann in der von ihm mitverantworteten Neuauflage 1957 als ewig „finassierender“ Machtpolitiker wieder nicht aufgenommen wurde
Hermite least squares optimization: a modification of BOBYQA for optimization with limited derivative information
No full textDerivative-free optimization tackles problems, where the derivatives of the objective function are unknown. However, in practical optimization problems, the derivatives of the objective function are often not available with respect to all optimization variables, but for some. In this work we propose the Hermite least squares optimization method: an optimization method, specialized for the case that some partial derivatives of the objective function are available and others are not. The main goal is to reduce the number of objective function calls compared to state of the art derivative-free solvers, while the convergence properties are maintained. The Hermite least squares method is a modification of Powell’s derivative-free BOBYQA algorithm. But instead of (underdetermined) interpolation for building the quadratic subproblem in each iteration, the training data is enriched with first and—if possible—second order derivatives and then least squares regression is used. Proofs for global convergence are discussed and numerical results are presented. Further, the applicability is verified for a realistic test case in the context of yield optimization. Numerical tests show that the Hermite least squares approach outperforms classic BOBYQA if half or more partial derivatives are available. In addition, it achieves more robustness and thus better performance in case of noisy objective functions
Knöbl, Wolfgang: Die Soziologie vor der Geschichte. Zur Kritik der Sozialtheorie, 316 S., Suhrkamp, Berlin 2022.
Get PDF„Geschichte“ sei „die Sinngebung des Sinnlosen“, formulierte 1919 Theodor Lessing provokant. Nach der Lektüre von Wolfgang Knöbls beeindruckendem Buch möchte man ergänzen, dass auch Soziologie die Sinngebung des Sinnlosen ist. Und wie Lessing seinerzeit die Aufmerksamkeit seiner Kollegen – vergeblich – auf die Fallen ihres Metiers hat lenken wollen, damit sie von ihren unreflektierten geschichtsphilosophischen Grundannahmen ablassen, so deckt Knöbl die Tücken auf, die seine Disziplin wegen ihrer zumeist unbewussten geschichtsphilosophischen Grundannahmen zu übersehen pflegt. Die größte Tücke ist zweifellos die Modernisierungstheorie, gegen die Knöbl seit Jahren zu Felde zieht, aber in diesem Buch geht es ihm ganz generell um die Prozessbegriffe, die die Soziologie seit Langem prägen. Anhand der drei Beispiele „Industrialisierung“, „Demokratisierung“ und „Individualisierung“ demonstriert er mit bemerkenswerter Literaturkenntnis (drei Sprachen, vier Disziplinen) die Probleme des freihändigen Umgangs mit ihnen. Aber es ist ja nicht nur die Soziologie, die Prozesse ohne Weiteres als realhistorische Gegebenheiten betrachtet. Politik- und Geschichtswissenschaft – letztere vorzugsweise, sofern sie sich als Historische Sozialwissenschaft betrachtet – begehen vielfach denselben Fehler, wenn sie Prozesse als quasi-naturhafte Verläufe in Richtung Gegenwart und Epochen ohne nähere Prüfung ihrer Tragfähigkeit verwenden, wo doch schon Johann Gustav Droysen seine Hörer ermahnt hat, „daß es in der Geschichte so wenig Epochen gibt wie auf dem Erdkörper die Linien des Äquators und der Meridiankreise […]“
Techno-Economic Assessment of Geothermal Resources in the Variscan Basement of the Northern Upper Rhine Graben
No full textDeep geothermal energy represents an essential component of the future energy supply because the resources greatly exceed the demand, and the base load capability can compensate for temporal fluctuations in wind and solar power. By far, the largest amount of heat is contained in the crystalline basement, accessible almost everywhere through deep drilling. An interdisciplinary approach for a techno-economic resource assessment was applied to provide stakeholders with a more reliable basis for decision-making in the Northern Upper Rhine Graben. This approach incorporated data from various sources such as boreholes, outcrops, geophysical surveys, geomechanical models, and operating geothermal power plants. Emphasis was placed on resources tied to large-scale fault zones, exhibiting preferential hydraulic properties. Uncertainties in the calculations were quantified using Monte Carlo simulations. The resource base in the basement of the Northern Upper Rhine Graben is about 830 PWhₜₕ, of which about 8.2–16.1 PWhₜₕ could potentially be extracted with current technologies in enhanced geothermal systems. A comprehensive sensitivity analysis was carried out, examining the economic influence of nine parameters. Considering the reference power plant and the energy prices before the Ukraine war began in February 2022, the geothermal reserves are about 65% of the resources. However, given the massive recent increase in heat and electricity prices, a higher percentage is also possible. Finally, a socio-economic-environmental assessment shows that in the Northern Upper Rhine Graben, geothermal resources largely coincide with favorable conditions at the surface, making the region a preferred target for geothermal utilization
Investigation of Engine Combustion and Auto-ignition of a Multicomponent Surrogate Fuel with NTC Behavior Under Knocking Conditions
No full textThe occurrence of knocking combustion is limiting the efficiency of modern spark ignition engine operation. Thus, an understanding of the processes at the knock limit is required for further optimization of the combustion process. In this work, the combustion of a multicomponent Toluene Reference Fuel (TRF) in a single-cylinder research engine is investigated under knocking conditions. The fuel exhibits a negative temperature coefficient (NTC) regime for thermodynamic conditions relevant to the engine operation. A precursor model is used to capture the auto-ignition process. Under homogeneous conditions, a two-stage auto-ignition is observed. Inside the NTC regime, the temperature affects both first-stage and second-stage auto-ignition delay times. With a subsequently conducted multi-cycle engine LES, the effects of temperature stratification and turbulent flame propagation on the local auto-ignition process are investigated. It is observed, that the NTC behavior leads to a widespread two-stage auto-ignition. The knock intensity observed in the experiments is directly related to the mass consumed by auto-ignition. This is due to the fast consumption of the auto-ignited mass by the flame front. With that, the NTC behavior affects the local auto-ignition process in the unburned mixture while the flame propagation determines the knock intensity for the operating conditions at the knock limit
Cellular automata rules solving the wireless sensor network coverage problem
No full textThe problem of an optimal coverage of a wireless sensor network area is considered. To solve this problem, a Cellular Automata (CA) approach is proposed. More specifically, the objective is to find CA rules which are able to cover the 2D space by a minimum number of so–called “Sensor Tiles”. A sensor tile consists of a von Neumann neighborhood of range 2 centered at sensor “point” and surrounded by 12 sensing “pixels”. Two probabilistic CA rules were designed that can perform this task. Results of an experimental study show that the first rule evolves very fast stable sub-optimal coverings, starting from a random configuration. The second rule finds optimal coverings, however it needs much more time for their evolution. The results are supported by a theoretical study on von Neumann neighborhoods and borrowing either from heuristics or from the spectral theory of circulant graphs
Non-Uniqueness and Energy Dissipation for 2D Euler Equations with Vorticity in Hardy Spaces
Get PDFWe construct by convex integration examples of energy dissipating solutions to the 2D Euler equations on ℝ² with vorticity in the Hardy space Hᵖ(ℝ²), for any 2/3<p<1
Relation between edge stress, bending strength, surface stress and fracture pattern of thermally toughened glass
No full textThermally toughened safety glass must meet safety requirements in the building industry. Here, destructive tests are defined in the product standards, which must be carried out on small, standardized format (360 mm × 1100 mm) glass elements to determine the fracture pattern and bending strength. This is costly and not in the interests of sustainability. As part of the quality control of optical anisotropy effects in thermally toughened glass, isochromatic scans that can provide information on the edge stress are acquired. The evaluation of the isochromatics and retardations at the edge with deduction of the edge stress and transfer to bending strength and fracture pattern could provide essential findings for assuring the safety requirements of thermally toughened glass. In this experimental investigation, the surface and edge stress were measured on standardized format thermally toughened safety glass, with different edge processing and glass thicknesses from three different suppliers. Afterwards, the fracture pattern is controlled, or the bending strength is analyzed in a destructive four-point bending test. Conclusively, the results from the photoelastic and destructive tests are compared to determine whether the photoelastic measurement methods used to measure surface and edge stress can be employed as quality control
Appearance and prevalence of float glass inclusions with a diameter smaller than 500 µm, focused on the identification of nickel sulphide
No full textIn most float glass productions, quality control systems will remove glass inclusions with diameters above 500 µm, since smaller inclusions are usually not visible to the human eye. Yet, they can still become relevant in glass construction, one example being nickel sulphide which can cause spontaneous fracture of thermally prestressed glass. This research presents statistical data on the prevalence of inclusions in the size range with a diameter between 50 and 500 µm, obtained from thorough scans of commercial float glass, showing that the inclusion size distribution follows an exponential curve. Also, many of the found inclusions are investigated by ultra-high-resolution optical microscopy down to resolutions close to the wavelength of visible light, the physical limit of such inspection, while still in the intact glass. Images taken under different lighting conditions and with different types of microscope cameras help in the identification and differentiation of inclusion types. Photoelastic stress measurements and laser interferometry also non-destructively show mechanical stress and deformation inside the glass around inclusions. Due to the risks emerging from this inclusion type, a special focus of the presented work is on the identification of nickel sulphide and its precursors which can be identified by its characteristic surface structure and colour as well as its shape
SKA2 regulated hyperactive secretory autophagy drives neuroinflammation-induced neurodegeneration
No full textHigh levels of proinflammatory cytokines induce neurotoxicity and catalyze inflammation-driven neurodegeneration, but the specific release mechanisms from microglia remain elusive. Here we show that secretory autophagy (SA), a non-lytic modality of autophagy for secretion of vesicular cargo, regulates neuroinflammation-mediated neurodegeneration via SKA2 and FKBP5 signaling. SKA2 inhibits SA-dependent IL-1β release by counteracting FKBP5 function. Hippocampal Ska2 knockdown in male mice hyperactivates SA resulting in neuroinflammation, subsequent neurodegeneration and complete hippocampal atrophy within six weeks. The hyperactivation of SA increases IL-1β release, contributing to an inflammatory feed-forward vicious cycle including NLRP3-inflammasome activation and Gasdermin D-mediated neurotoxicity, which ultimately drives neurodegeneration. Results from protein expression and co-immunoprecipitation analyses of male and female postmortem human brains demonstrate that SA is hyperactivated in Alzheimer’s disease. Overall, our findings suggest that SKA2-regulated, hyperactive SA facilitates neuroinflammation and is linked to Alzheimer’s disease, providing mechanistic insight into the biology of neuroinflammation