Die Ablaich- und Interstitialphase der Äsche (Thymallus thymallus L.) - Grundlagen und Auswirkungen anthropogener Belastungen -

Die vorliegende Arbeit beschäftigt sich mit den Grundlagen der Ablaich- und Interstitialphase der Äsche ( Thymallus thymallus) und den Auswirkungen anthropogener Gewässerveränderungen auf die frühen Entwicklungsstadien. In einem deutschen Mittelgebiergsfluss, der Lahn, wurde das Ablaichverhalten der Äsche beobachtet und die Anzahl und Struktur verschiedener Äschenlaichplätze aufgenommen. Das Laichsubstrat wurde erstmalig mit standardisierten Siebsätzen (0,063-63mm) ausgesiebt und das Larvenaufkommen von 1995-1999 dokumentiert. Mithilfe von Schlauchsystemen mit verschiedenen Tiefenhorizonten (10, 20 und 30cm Sedimentiefe)konnten die Milieubedingungen (O2, CO2, NO3-, NO2-, NH4+, NH3, o-PO4-P, pH-Wert, Temp.,Leitfähigkeit und SBV)im Interstitial an natürlichen Laichplätzen erfasst werden. Zusätzlich wurden stoffliche Belastungsszenarien durchgeführt, bei denen Kiesboxen mit Äscheneiern und Schlauchsysteme in Gewässerabschnitten mit unterschiedlicher stofflicher Belastung (vor und nach der Ausleitungsstrecke einer Kläranlage) vergraben wurden. Die Boxen wurden zu drei verschiedenen Entwicklungszeitpunkten (Augenpunktstadium, Schlupf und Aufschwimmen) geborgen. Die Mortalität der Eier und Larven wurde notiert und die verbliebenen Tiere unter dem Binokular vermessen. Durch die zeitgleiche Onlinemessung der chemisch-physikalischen Parameter in der freien Welle konnte die Tagesperiodik der o.g. Parameter dokumentiert und ihr Verlauf im Interstitial modelliert werden. In der Lahn wandern die Äschen Anfang April an die Laichplätze, wo die Männchen langgestreckte Reviere von 4,5 bis 8 m² verteidigen. Der Ablaichvorgang begann nachmittags ab einer Wassertemp. von 8°C. Zum Ablaichen wurden überströmte Flachwasserzonen (Mittelwerte: Oberflächenströmung: 61 cm/s, Grundströmung 34 cm/s, Wassertiefe 41 cm) genutzt. Zwischen den einzelnen Ablaichvorgängen waren die Äschen in Ruhehabitaten (ufernahe Kolke mit Ästen und Totholz bedeckt) zu finden. Das Laichsubstrat war überwiegend kiesig. Es bestand überwiegend aus Grobkies (Korngöße 20-63 mm: 30-50%), einigen Steinen (>63 mm: 3-35%) und Mittelkies (6,3-20 mm: 14-30%). Der Feinsedimentanteil (< 2 mm) war an allen drei untersuchten Flussabschnitten gering (5,3-12,3%). Die Dauer der Embryonalentwicklung war temperaturabhängig und betrug in der Lahn durchschnittl. 156,3 Tagesgrade (16,9 Tage bei 9,25°C). Die limitiernden Faktoren der Ei- und Embryonalentwicklung der Äsche an der Lahn waren die Ammoniakkonzentrationen und der Feinsedimentanteil im Interstitial. Im stofflich stark belasteten Versuchsfeld traten Ammoniakkonzentrationen bis 108 µg/l NH3-N vor dem Schlupf auf. In der sensiblen Phase nach dem Schlupf wurden NH3-N Werte bis 52 µg/l gemessen, die zum Absterben aller Äscheneier führte. Als Grenzwert für die Larvalentwicklung wird eine NH3-N Konzentration von 25 µg/l diskutiert. An den natürlichen Laichplätzen korrelierte die Anzahl aufschwimmender Äschenlarven signifikant negativ mit dem Feinsedimentanteil (Korngröße < 2 mm). Der höchste Feinsedimentanteil von 23,7% trat nach Ausbelieben des Winterhochwassers im Jahr 1996 auf und führte zu einer Halbierung des Äschenlarvenaufkommens. Der pH-Wert der freien Welle zeigte ausgeprägte tagesperiodische Schwankungen (7,3-9,9) mit Maximalwerten in den Nachmittagsstunden. An den natürlichen Laichplätzen lag der pH-Wert mit 8-8,9 in 10 cm Sedimenttiefe im alkalischen Bereich. Die Sauerstoffkonzentration lag tagsüber immer im übersättigten Bereich (11,7 - 15 mg/l in 10 cm Sedimenttiefe, 11,2 - 16,5 mg/l in der freien Welle). Nachts sanken die O2-Werte in der freien Welle bis 5,9 mg/l. Sowohl die hohen pH-Werte als auch die hohen Sauerstoffkonzentrationen am Tage warenb auf die erhöhte Photosyntheserate der Algen im eutrophierten Gewässer zurückzuführen

Enabling Quality-oriented Process Development for sulfidic All-Solid-State Battery Cathodes

After major advances in material research throughout recent years, the industrialization of all-solid-state batteries now depends on the development of cost-effective production technology for novel materials and components. To enable a fast production scale-up and complex process interdependency handling, production engineering needs a quantitative evaluation and comparison approach for manufacturing strategies and process parameter settings. To address this challenge, we derive microstructural quality criteria from specifications at the product-level such as driving range and charging speed of battery electric vehicles. These range from porosity and agglomerate density on a macroscopic level to microscopic properties such as pore size distribution and particle contacts. By listing comprehensive characterization methods, the work enables engineers to efficiently evaluate these criteria. Experimentally applying the proposed approach, the influence of different mixing process parameters is analyzed. Thereby, sulfidic composite cathodes manufactured in a scalable procedure are used as samples

Investigating Rock Mass Conditions and Implications for Tunnelling and Construction of the Amethyst Hydro Project, Harihari.

The Amethyst hydro project was proposed on the West Coast of New Zealand as an answer to the increasing demand for power in the area. A previous hydro project in the area was deemed unviable to reopen so the current project was proposed. The scheme involves diverting water from the Amethyst Ravine down through penstocks in a 1040m tunnel and out to a powerhouse on the floodplain of the Wanganui River. The tunnel section of the scheme is the focus of this thesis. It has been excavated using drill and blast methods and is horseshoe shaped, with 3.5x3.5m dimensions. The tunnel was excavated into Haast Schist through its whole alignment, although the portal section was driven into debris flow material. The tunnel alignment and outflow portal is approximately 2km Southeast of the Alpine Fault, the right lateral thrusting surface expression of a tectonically complex and major plate boundary. The Amethyst Ravine at the intake portal is fault controlled, and this continuing regional tectonic regime has had an impact on the engineering strength of the rockmass through the orientation of defects. The rock is highly metamorphosed (gneissic in places) and is cut through with a number of large shears. Scanline mapping of the tunnel was completed along with re-logging of some core and data collection of all records kept during tunneling. Structural analysis was undertaken, along with looking at groundwater flow data over the length of the tunnel, in order to break the tunnel up into domains of similar rock characteristics and investigate the rockmass strength of the tunnel from first principles. A structural model, hydrological model and rockmass model were assembled, each showing the change in characteristics over the length of the tunnel. The data was then modeled using the 3DEC numerical modelling software. It was found that the shear zones form major structural controls on the rockmass, and schistosity changes drastically to either side of these zones. Schistosity in general steepens in dip up the tunnel and dip direction becomes increasingly parallel to the tunnel alignment. Water is linked to shear position, and a few major incursions of water (up to 205 l/s) can be linked to large (1.6m thick) shear zones. Modeling illustrated that the tunnel is most likely to deform through the invert, with movement also capable of occurring in the right rib above the springline and to a lesser extent in the left rib below the springline. This is due to the angle of schistosity and the interaction of joints, which act as cut off planes. The original support classes for tunnel construction were based on Barton’s Q-system, but due to complicated interactions between shears, foliations and joint sets, the designed support classes have been inadequate in places, leading to increased cost due to the use of supplementary support. Modeling has shown that the halos of bolts are insufficient due to the >1m spacing, which fails to support blocks which can be smaller than this in places due to the close spacing of the schistosity. It is recommended that a more broad support type be used in place of discreet solutions such as rock bolts, in order to most efficiently optimize the support classes and most effectively support the rock mass

Approach For Data-Based Optimization In Cell Finishing of Battery Production

Due to the global warming, a significant reduction in the emission of greenhouse gases is necessary. One part of the solution is the electrification of today's transportation and traffic sector. An essential component of today's electric vehicles is the lithium-ion battery (LIB), which is largely responsible for their range, performance and cost. In order to increase the use of such climate-friendly technologies, it is therefore essential to reduce the production costs of LIBs. With a duration of up to three weeks, the process steps of formation and aging are particularly capital-intensive and have high demands on storage capacities. Formation and aging therefore account for up to 30% of the manufacturing costs for battery cells. During formation, the solid electrolyte interphase (SEI) is formed, which has a major influence on the quality and lifetime of the LIB, among other things. In order to reduce production costs and simultaneously increase battery cell quality, it is therefore necessary to optimize the formation and aging process. Because of the complexity and the interdependency of these processes towards previous process parameters the application of machine learning algorithm is predestined to optimize these process steps. For this purpose, a general approach for the application of a machine learning algorithm in the formation and aging are first analysed and relevant parameters from the literature as well as reasonable assumptions about the structure are derived. Based on these requirements and boundary conditions a machine learning algorithm structure will be developed to optimize the cell finishing process in the battery cell production

9-Bromo-9-borafluorene

The title compound, C12H8BBr, crystallizes with three essentially planar mol­ecules (r.m.s. deviations = 0.018, 0.020 and 0.021Å) in the asymmetric unit: since the title compound is rigid, there are no conformational differences between these three mol­ecules. The crystal packing resembles a herringbone pattern

Tailoring Soft Local Zones in Quenched Blanks of the Steel 22MnB5 by Partial Pre-cooling with Compressed Air

The high-strength boron steel 22MnB5 steel is widely used for automotive lightweight constructions. A novel approach is promising to tailor strength and ductility in the hardened condition using locally pre-tempered sheets for the hot stamping process. It results in the formation of locally soft spots where mechanical joining is subsequently intended. A slow pre-cooling of the later joining zones with cooling rates below a certain critical cooling rate for obtaining a decreased strength in these regions is required. A tubular air cooling system suited for this task is presented and tested in a process where the subsequent quenching of the overall sheet is realized by rapid cooling in a water bath. Varying the air pressure and cooling duration allows controlling the size of the softened local spot in a wide range and still obtaining a bainitic microstructure. Using two-stage cooling with point jet nozzles and a subsequent hot stamping process with water-cooled dies resulted in a main sheet hardness of about 470 HV5 and of 260 HV5 in the pre-cooled spots, respectively

Comparative Analysis of Lithium Metal Anode Production Methods: Evaluating Liquid-Based Manufacturing Technology for Mass Production

Lithium metal anodes (LMA) have gained significant attention for their potential to revolutionize rechargeable battery technology, offering high theoretical capacity and low electrode potential. Their implementation in various applications, such as electric vehicles and portable electronics, holds the promise of significantly improving energy density and battery performance. Additionally, the successful integration of lithium metal anodes remains a crucial and yet-to-be-resolved challenge in the development of All-Solid-State Batteries (ASSBs), which aim to provide safer and more efficient energy storage systems. Overcoming the production challenges associated with lithium metal anodes is essential for realizing their full potential. This paper presents a comprehensive technology analysis and evaluation of production methods for lithium metal anodes. The analysis explores various techniques and their potential for mass production. Furthermore, this analysis evaluates the viability of each approach by considering factors such as the potential for performance improvement, cost savings, quality enhancement, and the technology readiness level. The paper outlines future directions for the development of these techniques while focusing on the liquid-based processing approach, aiming to address quality issues and enhance its scalability for large-scale production. In conclusion, this technology analysis and evaluation underscores the potential of liquid-based manufacturing technology for the mass production of high-quality lithium metal anodes and highlights the need to overcome production challenges. An approach is presented that offers a way to work through the challenge of LMA production, paving the way to next-generation battery cells