Spatio-temporal distribution of induced seismicity in flooded mines in the Ruhr area - interpretation by geomechanical numerical modelling

Induced seismicity during mine flooding is the focus of the FloodRisk project. One of the study areas is the Ruhr area, which is characterised by centuries of intensive coal mining. After the closure of the last mines, controlled flooding began. Within the FloodRisk project, we investigate ground uplift, stress changes due to pore pressure changes and the reactivation potential of faults to explain induced seismicity. We concentrate on the seismicity monitoring and geomechanics of the Haus Aden catchment, for which we investigate the relationship between water rise, tectonic stress and induced seismicity. The monitoring of seismicity is based on a network of up to 30 short-period seismic stations installed by the Ruhr University in the area of the former "Bergwerk Ost", which exhibited the highest seismicity in the Ruhr area during active mining. The stations cover an area of about 160 km 2 and are spaced between 0.5 and 3.5 km apart. They allow continuous monitoring of seismicity. Since 2019, more than 2200 induced events have been localised. A prerequisite for the interpretation of seismicity is a detailed localisation of the events. The relative localisation of the induced earthquakes has significantly reduced the location uncertainty and allowed the spatial and temporal evolution of earthquake clusters due to the rise in mine water levels to be studied. The resulting pattern of seismicity was compared with known underground structures. This comparison indicates that most of the events occur approximately 300 m below the main pillars between the longwall panels in the already flooded deepest level of the mine. A generic FE numerical model was developed for a section of the Heinrich Robert mine based on the geometry of the pillars, shafts and longwall panels. The stress data for model calibration are based on a compilation of the regional stress state in the eastern Ruhr area. For this purpose, hydraulic fracture tests carried out in the mines to minimise rock bursts were re-evaluated and compared with stress orientations derived from independent sources such as borehole fractures and earthquake source mechanisms. Using this 3D numerical approach, we conclude that there is increased vertical stress within and below the pillars as a result of stress arching. As the horizontal stress changes below the mine levels are small, this results in increasing differential stresses that can lead to the observed events below the mine level when the mine water level rises

NEED FOR PHOSPHORUS INPUT IN AUSTRIAN ORGANIC FARMING?

On organic farms, phosphorus (P) balances are often negative because no or little P is imported into the farms. Negative P balances may deteriorate P availability over time. We calculated P balances of the main farm production types in organic farming for the main Austrian production areas. Using data from various data bases and expert knowledge, we applied the sustainability assessment tool REPRO for calculations. The P balances were balanced to slightly deficient for organic forage dairy farms, cash crop farms and permanent crop farms, and slightly to highly surplus on organic refinement, pig producing farms. Deficient P balances, mainly on organic cash crop farms, call for P input especially on farms where available P fractions in the soil are very low and / or P stocks in the soils are low, i.e. on sandy soils and on some calcareous soils. Possibilities for enhancing P mobilisation are discussed. There is an urgent need to close nutrient cycles on the farm and regional scale and to substitute P from rock phosphate reserves by alternative P fertilisers also in organic farming

Vergleich von Treibhausgasemissionen unterschiedlich wirtschaftender Modellbetriebe im Alpenvorland

About 8.8 % (UBA 2010) of the total greenhouse gas (GHG) emissions in Austria are caused by agricultural practices. Besides the release of climate relevant gases, C-sequestration occurs depending on the natural conditions and farming system. The focus of the project was to describe the GHG-emissions and sinks of the most relevant farming types, both organic and conventional, within the main production areas in Austria. Results of an intensively cultivated region in the North-West are presented. Based on the input data, six model-farms were created with the programme REPRO, whereby forage production, cash crops and refinement systems were considered. All systems had a positive humus balance and sequestered carbon in the soil, especially forage production systems. Due to the use of mineral fertilizers, a higher N-balance occurred in all conventional systems. Organic systems on the other hand were able to utilize nutrients to a wider extent. The GHG-potential related to area was at least 29 % higher at conventional compared to organic systems, whereby N2O-emissions, calculated according to IPCC 1997, were most relevant. Differences were reduced and results even reversed calculating the GHG-potential per product unit. When calculating the N2O-Emissions with an increased N2O emission factor of 2.5 % of N input in a scenario, the emissions increased almost proportionally

Modellberechnungen für treibhausgasrelevante Emissionen und Senken in landwirtschaftlichen Betrieben Ost-Österreichs

Landwirtschaftliche Nutzungssysteme sind in unterschiedlicher Weise an der Emission und Speicherung von klimarelevanten Gasen (CO2, CH4 und N2O) beteiligt. Die wesentlichen Projektziel sind die Bereitstellung von Daten- und Berechnungsgrundlagen für eine umfassende Darstellung von Profilen treibhausgasrelevanter Emissionen und Senken landwirtschaftlicher Betriebe in den acht Hauptproduktionsgebieten Österreichs. In jeder Region werden die beiden vorherrschenden Betriebstypen mit dem Programm REPRO modelliert, da es die Analyse der C-, N- und Energieflüsse im System Boden-Pflanze-Tier-Umwelt kombiniert. Als Beispiel werden die Ergebnisse des Hauptproduktionsgebietes "Nordöstliches Flach- und Hügelland" im Anschluss präsentiert

Nicht-harmonische Schwingungen am Huygens-Raebiger Pendel

In der Lehramtsausbildung haben im physikalischen Praktikum zunehmend computergestützte Versuche ihren Platz gefunden. Hierbei ist nicht nur die computergestützte Messwertaufnahme von Vorteil. Die Studierenden haben auch bei der Auswertung die Möglichkeit sich mit vergleichsweise geringem Aufwand mit mathematischen Modellierungen von physikalischen Sachverhalten zu beschäftigen. Aus einer Reihe entwickelter Versuche für das physikalische Praktikum an der Pädagogischen Hochschule Freiburg beschäftigt sich ein Versuch mit den Unterschieden zwischen einer harmonischen Schwingung und einer nicht-harmonischen Schwingung. Es soll mit diesem Versuch gezeigt werden, dass für große Winkel ein physikalisches Pendel keine harmonische Schwingung vollzieht und dass dieser Effekt bei längeren Pendeln größer ist als bei kürzeren. In diesem Zusammenhang werden die Grenzen einer mathematischen Modellierung mit Hilfe eines CAS veranschaulicht. Als physikalisches Pendel wird das Huygens-Raebiger Pendel verwendet – ein Pendel das sowohl gekoppelt als ein Pendel schwingen kann, als auch entkoppelt als sieben „kleine“, sich durch die Länge der Stange unterscheidende, Pendel. Im Folgenden werden der Versuch und die Modellierung der Messergebnisse vorgestellt

Nicht-harmonische Schwingungen am Huygens-Raebiger Pendel

In der Lehramtsausbildung haben im physikalischen Praktikum zunehmend computergestützte Versuche ihren Platz gefunden. Hierbei ist nicht nur die computergestützte Messwertaufnahme von Vorteil. Die Studierenden haben auch bei der Auswertung die Möglichkeit sich mit vergleichsweise geringem Aufwand mit mathematischen Modellierungen von physikalischen Sachverhalten zu beschäftigen. Aus einer Reihe entwickelter Versuche für das physikalische Praktikum an der Pädagogischen Hochschule Freiburg beschäftigt sich ein Versuch mit den Unterschieden zwischen einer harmonischen Schwingung und einer nicht-harmonischen Schwingung. Es soll mit diesem Versuch gezeigt werden, dass für große Winkel ein physikalisches Pendel keine harmonische Schwingung vollzieht und dass dieser Effekt bei längeren Pendeln größer ist als bei kürzeren. In diesem Zusammenhang werden die Grenzen einer mathematischen Modellierung mit Hilfe eines CAS veranschaulicht. Als physikalisches Pendel wird das Huygens-Raebiger Pendel verwendet – ein Pendel das sowohl gekoppelt als ein Pendel schwingen kann, als auch entkoppelt als sieben „kleine“, sich durch die Länge der Stange unterscheidende, Pendel. Im Folgenden werden der Versuch und die Modellierung der Messergebnisse vorgestellt

Liquid-Based Multijunction Molecular Solar Thermal Energy Collection Device

Photoswitchable molecules-based solar thermal energy storage system (MOST) can potentially be a route to store solar energy for future use. Herein, the use of a multijunction MOST device that combines various photoswitches with different onsets of absorption to push the efficiency limit on solar energy collection and storage is explored. With a parametric model calculation, it is shown that the efficiency limit of MOST concept can be improved from 13.0% to 18.2% with a double-junction system and to 20.5% with a triple-junction system containing ideal, red-shifted MOST candidates. As a proof-of-concept, the use of a three-layered MOST device is experimentally demonstrated. The device uses different photoswitches including a norbornadiene derivative, a dihydroazulene derivative, and an azobenzene derivative in liquid state with different MOSTproperties, to increase the energy capture and storage behavior. This conceptional device introduces a new way of thinking and designing optimal molecular candidates for MOST, as much improvement can be made by tailoring molecules to efficiently store solar energy at specific wavelengths

Projektvorstellung: C - Speicherung in Böden landwirtschaftlicher Betriebssysteme Österreichs

Die Projektziele bestehen im Wesentlichen in der Optimierung und Bereitstellung der Daten- und Berechnungsgrundlagen im Bereich Pflanzenbau und Humusgehalte im Boden, um die Profile der treibhausgas-relevanten Emissionen und Senken in landwirtschaftlichen Betrieben Österreichs darzustellen, sowie in der Modellierung treibhausgasrelevanter Emissionen und Senken der wichtigsten landwirtschaft-lichen Betriebstypen Österreichs (Martkfrucht-, Futterbau-, Veredelungs-, Dauerkultur-, Kombinations-, und landwirtschaftliche Gemischtbetriebe) in den Hauptproduktionsgebieten

Click chemistry-based tracking reveals putative cell wall-located auxin binding sites in expanding cells

Abstract Auxin is a key plant regulatory molecule, which acts upon a plethora of cellular processes, including those related to cell differentiation and elongation. Despite the stunning progress in all disciplines of auxin research, the mechanisms of auxin-mediated rapid promotion of cell expansion and underlying rearrangement of cell wall components are poorly understood. This is partly due to the limitations of current methodologies for probing auxin. Here we describe a click chemistry-based approach, using an azido derivative of indole-3-propionic acid. This compound is as an active auxin analogue, which can be tagged in situ. Using this new tool, we demonstrate the existence of putative auxin binding sites in the cell walls of expanding/elongating cells. These binding sites are of protein nature but are distinct from those provided by the extensively studied AUXIN BINDING PROTEIN 1 (ABP1). Using immunohistochemistry, we have shown the apoplastic presence of endogenous auxin epitopes recognised by an anti-IAA antibody. Our results are intriguingly in line with previous observations suggesting some transcription-independent (non-genomic) activity of auxin in cell elongation

Automatic Optimization of Lipid Models in the Martini Force Field Using SwarmCG.

After two decades of continued development of the Martini coarse-grained force field (CG FF), further refinment of the already rather accurate Martini lipid models has become a demanding task that could benefit from integrative data-driven methods. Automatic approaches are increasingly used in the development of accurate molecular models, but they typically make use of specifically designed interaction potentials that transfer poorly to molecular systems or conditions different than those used for model calibration. As a proof of concept, here, we employ SwarmCG, an automatic multiobjective optimization approach facilitating the development of lipid force fields, to refine specifically the bonded interaction parameters in building blocks of lipid models within the framework of the general Martini CG FF. As targets of the optimization procedure, we employ both experimental observables (top-down references: area per lipid and bilayer thickness) and all-atom molecular dynamics simulations (bottom-up reference), which respectively inform on the supra-molecular structure of the lipid bilayer systems and on their submolecular dynamics. In our training sets, we simulate at different temperatures in the liquid and gel phases up to 11 homogeneous lamellar bilayers composed of phosphatidylcholine lipids spanning various tail lengths and degrees of (un)saturation. We explore different CG representations of the molecules and evaluate improvements a posteriori using additional simulation temperatures and a portion of the phase diagram of a DOPC/DPPC mixture. Successfully optimizing up to ∼80 model parameters within still limited computational budgets, we show that this protocol allows the obtainment of improved transferable Martini lipid models. In particular, the results of this study demonstrate how a fine-tuning of the representation and parameters of the models may improve their accuracy and how automatic approaches, such as SwarmCG, may be very useful to this end. </p