Technische Universität Bergakademie Freiberg: Qucosa
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Wärmeübergang bei der Tropfenkondensation aus feuchter Luft
Get PDFIn dieser Arbeit wird der Wärmeübergang bei der Tropfenkondensation aus feuchter, turbulent strömender Luft experimentell untersucht. Die Versuchsstrecke besteht aus einem horizontalen Kanal in den Abmessungen (12 × 32 × 750) mm . Die Kondensation findet auf einem mit Kunststoff beschichteten Wärmestromsensor statt, der in einer der vertikalen Kanalwände bündig eingelassen ist. Experimentell erfasst werden der Wärmedurchgangswiderstand der Kondensatschicht durch Anwendung eines theromografischen Verfahrens sowie der in den Sensor eindringende Wärmestrom. Messergebnisse werden für verschiedene Strömungsgeschwindigkeiten, Luftfeuchten und -temperaturen, sowie für variierende Temperaturen der Sensoroberfläche gewonnen. Die Messergebnisse werden mit den Vorhersagen eines aus dem Kontext der Filmkondensation entlehnten Modells verglichen. Systematische Abweichungen konnten mit der Größe der Tropfen auf der Oberfläche korreliert werden. Die ermittelten Korrelationsgleichungen werden angegeben. Die Übertragbarkeit des hier entwickelten Ansatzes auf andere Geometrien und Randbedingungen konnte durch seine Anwendung auf externe Messdaten gezeigt werden
Untersuchungen zum Freisetzungsverhalten von Störkomponenten aus Energierohstoffen unter reduzierenden und oxidierenden Bedingungen
Get PDFDie vorliegende Dissertationsschrift beschreibt Experimente zur Weiterentwicklung der Methode der elektrothermischen Verdampfung mit induktiv gekoppeltem Plasma und optischer Emissionsspektroskopie (ETV-ICP OES). Ziel ist die Analyse der Mobilisierung einzelner Elemente in Verbrennungsgasatmosphären, um so das Verschmutzungs- und Verschlackungspotential von Energierohstoffen abschätzen zu können. Zur Simulation der Atmosphäre wird Sauerstoff zum Argon-Gasstrom der Verdampfungseinheit in verschiedenen Verhältnissen zugesetzt, weshalb einige Bauteile der ETV und alle Methodenparameter angepasst werden müssen. Der Einfluss der Gasatmosphäre sowie des Temperaturprogrammes auf die Freisetzung der Elemente wird anhand von drei Kohlen unterschiedlicher Inkohlung und Mineralstoffanteile untersucht und die Analysenmethode dementsprechend optimiert. Im Anschluss erfolgt die Anwendung der entwickelten Methode auf acht Argonne Premium Kohlen sowie auf verschiedene Biomassen und Klärschlämme.:1 Motivation und Aufgabenstellung 12
2 Stand der Technik 15
2.1 Energierohstoffe 15
2.2 Ansatzbildung und Korrosion im Kraftwerk 17
2.2.1 Ansatzbildungsmechanismen 17
2.2.2 Korrosion 20
2.2.3 Freisetzung von Störkomponenten 21
2.2.3.1 Schwefel 21
2.2.3.2 Chlor 21
2.2.3.3 Alkalien 22
2.2.4 Analysemethoden zur Ermittlung der Freisetzung von Störkomponenten 23
3 Eingesetzte Methoden und Parameter 27
3.1 ETV-ICP OES 27
3.2 Thermodynamische Gleichgewichtsberechnungen 31
4 Methodenentwicklung modifizierte ETV-ICP OES 33
4.1 Anpassung des ETV-Systems an simulierte Prozessbedingungen 34
4.1.1 Auswahl der Gasatmosphären 36
4.1.2 Vergleich Standardrohr und SiC-beschichtetes Rohr 38
4.1.3 Einfluss der Beschichtung der Probentiegel 39
4.1.4 Fazit 42
4.2 Temperaturprogramm 43
4.3 Linienauswahl 44
4.4 Kalibration für quantitative Analysen 46
4.5 Datenbearbeitung 49
4.5.1 Korrekturfaktor für Massenbilanz 50
4.5.2 Argon-Korrektur 51
4.5.3 Intensität und Freisetzungsverlauf 53
4.5.4 Zusammenfassung notwendiger Datenbearbeitung 56
4.6 Einfluss der modifizierten Methode auf die Kohlematrix 56
4.6.1 Probenauswahl und Charakterisierung 57
4.6.1.1 Bestimmung der Bindungsformen von Kalium und Natrium 59
4.6.2 Elementfreisetzungsverhalten – Analyse der Kohleproben 64
4.6.2.1 Mineralreiche Kohle – 4419 64
4.6.2.2 Mineralarme Braunkohle – 3922 73
4.6.2.3 Steinkohlestandard – 1632d 81
4.6.2.4 Sonderfall Chlor 87
4.7 Fehlerbetrachtung 89
4.8 Zusammenfassung der Methodenentwicklung 92
5 Anwendung der Methode 96
5.1 Argonne Premium Kohlen 96
5.1.1 Kalium 98
5.1.2 Natrium 101
5.1.3 Schwefel 103
5.1.4 Zusammenfassung der Analysen an den APCs 106
5.2 Klärschlamm 106
5.2.1 Probenauswahl 107
5.2.2 Kalium 108
5.2.3 Natrium 111
5.2.4 Schwefel 113
5.2.5 Phosphor 115
5.2.6 Zusammenfassung der Klärschlammanalysen 118
5.3 Biomasse 118
5.3.1 Probencharakterisierung 119
5.3.2 Freisetzungsverhalten der Elemente 120
5.3.3 Zusammenfassung der Analysen an den Biomassen 123
5.4 Rückschlüsse der Ergebnisse auf reale Prozesse 124
6 Zusammenfassung und Ausblick 126
7 Anhang 130
7.1 Analysenmethoden zur Probencharakterisierung 130
7.1.1 Brennstoffanalyse 130
7.1.2 Röntgenfluoreszenzspektroskopie 131
7.1.3 Röntgendiffraktometrie 132
7.1.4 Thermische Analysen 134
7.1.5 Weitere Parameter für die FactSageTM-Berechnungen 135
7.2 Zusatzinformationen zur Methodenentwicklung 136
7.2.1 Methodenparameter 136
7.2.2 Probencharakterisierung 140
7.3 Zusatzinformationen zur Anwendung der modifizierten Methode 147
7.3.1 APC 147
7.3.2 Klärschlämme 148
8 Referenzen 150
9 Veröffentlichungsliste 160
10 Verzeichnisse 161
10.1 Abbildungsverzeichnis 161
10.2 Tabellenverzeichnis 166
10.3 Abkürzungsverzeichnis 168This dissertation describes the development of a method to analyze the mobilization of individual elements in combustion gas atmospheres with the help of electrothermal evaporation in combination with inductively coupled plasma optical emission spectros-copy (ETV-ICP OES) to estimate the pollution and slagging potential of energy feed-stocks. To simulate the atmosphere, oxygen is added to the argon gas stream of the evaporation unit in different ratios. To that end, some components of the ETV unit and all method parameters have to be adjusted. The influence of the gas atmosphere as well as the temperature program on the release of the elements is investigated on the basis of three coals of different degree of carbonization and mineral content and the analysis method is optimized accordingly. Subsequently, the method is applied to analyze eight Argonne Premium coals as well as various biomasses and sewage sludges.:1 Motivation und Aufgabenstellung 12
2 Stand der Technik 15
2.1 Energierohstoffe 15
2.2 Ansatzbildung und Korrosion im Kraftwerk 17
2.2.1 Ansatzbildungsmechanismen 17
2.2.2 Korrosion 20
2.2.3 Freisetzung von Störkomponenten 21
2.2.3.1 Schwefel 21
2.2.3.2 Chlor 21
2.2.3.3 Alkalien 22
2.2.4 Analysemethoden zur Ermittlung der Freisetzung von Störkomponenten 23
3 Eingesetzte Methoden und Parameter 27
3.1 ETV-ICP OES 27
3.2 Thermodynamische Gleichgewichtsberechnungen 31
4 Methodenentwicklung modifizierte ETV-ICP OES 33
4.1 Anpassung des ETV-Systems an simulierte Prozessbedingungen 34
4.1.1 Auswahl der Gasatmosphären 36
4.1.2 Vergleich Standardrohr und SiC-beschichtetes Rohr 38
4.1.3 Einfluss der Beschichtung der Probentiegel 39
4.1.4 Fazit 42
4.2 Temperaturprogramm 43
4.3 Linienauswahl 44
4.4 Kalibration für quantitative Analysen 46
4.5 Datenbearbeitung 49
4.5.1 Korrekturfaktor für Massenbilanz 50
4.5.2 Argon-Korrektur 51
4.5.3 Intensität und Freisetzungsverlauf 53
4.5.4 Zusammenfassung notwendiger Datenbearbeitung 56
4.6 Einfluss der modifizierten Methode auf die Kohlematrix 56
4.6.1 Probenauswahl und Charakterisierung 57
4.6.1.1 Bestimmung der Bindungsformen von Kalium und Natrium 59
4.6.2 Elementfreisetzungsverhalten – Analyse der Kohleproben 64
4.6.2.1 Mineralreiche Kohle – 4419 64
4.6.2.2 Mineralarme Braunkohle – 3922 73
4.6.2.3 Steinkohlestandard – 1632d 81
4.6.2.4 Sonderfall Chlor 87
4.7 Fehlerbetrachtung 89
4.8 Zusammenfassung der Methodenentwicklung 92
5 Anwendung der Methode 96
5.1 Argonne Premium Kohlen 96
5.1.1 Kalium 98
5.1.2 Natrium 101
5.1.3 Schwefel 103
5.1.4 Zusammenfassung der Analysen an den APCs 106
5.2 Klärschlamm 106
5.2.1 Probenauswahl 107
5.2.2 Kalium 108
5.2.3 Natrium 111
5.2.4 Schwefel 113
5.2.5 Phosphor 115
5.2.6 Zusammenfassung der Klärschlammanalysen 118
5.3 Biomasse 118
5.3.1 Probencharakterisierung 119
5.3.2 Freisetzungsverhalten der Elemente 120
5.3.3 Zusammenfassung der Analysen an den Biomassen 123
5.4 Rückschlüsse der Ergebnisse auf reale Prozesse 124
6 Zusammenfassung und Ausblick 126
7 Anhang 130
7.1 Analysenmethoden zur Probencharakterisierung 130
7.1.1 Brennstoffanalyse 130
7.1.2 Röntgenfluoreszenzspektroskopie 131
7.1.3 Röntgendiffraktometrie 132
7.1.4 Thermische Analysen 134
7.1.5 Weitere Parameter für die FactSageTM-Berechnungen 135
7.2 Zusatzinformationen zur Methodenentwicklung 136
7.2.1 Methodenparameter 136
7.2.2 Probencharakterisierung 140
7.3 Zusatzinformationen zur Anwendung der modifizierten Methode 147
7.3.1 APC 147
7.3.2 Klärschlämme 148
8 Referenzen 150
9 Veröffentlichungsliste 160
10 Verzeichnisse 161
10.1 Abbildungsverzeichnis 161
10.2 Tabellenverzeichnis 166
10.3 Abkürzungsverzeichnis 16
EBSD characterization of the eutectic microstructure in hypoeutectic Fe-C and Fe-C-Si alloys
Get PDFHypoeutectic Fe-C and Fe-C-Si model alloys were produced at different solidification conditions. Copper mold casting yields low cooling rates promoting the formation of a eutectic microstructure characterized by two morphologies: elongated cementite plates and a rod structure growing perpendicular to the plates, i.e. austenite rods in a cementite matrix. Electron beam surface remelting generates a mainly plate-like eutectic due to rapid solidification. The microstructures were characterized by light-optical microscopy and electron backscatter diffraction (EBSD). The latter allows for a spatially resolved investigation of the growth crystallography of the eutectic phases. Thereby, a possible existence of crystallographic orientations relationships between cementite and austenite within the plate-like eutectic was assessed experimentally. The eutectic phases were found to grow largely crystallographically independently. Moreover, ferrite and eutectic cementite within the decomposed eutectic microstructure comply frequently with the Bagaryatsky or the Pitsch-Petch orientation relationship. Complementary X-ray diffraction (XRD) analysis reveals a pronounced cementite {002} texture in the microstructure produced by mold casting. Characteristic changes in the lattice parameters indicate that as-cast cementite is non-stoichiometric
Wärmeleitung durch Schlackenschichten
Get PDFThe study demonstrates the systematic investigation of thermophysical properties of synthetic slags and commercial mold fluxes in a wide temperature range. Focal points of the work are (i) the development and the construction of the transient hot-wire method for the thermal conductivity measurement of solid and molten slags and (ii) the investigation of the thermal conductivity of all layers of casting powders being in the mold. The work includes viscosity, density and surface tension measurements as well as the investigation of characteristic temperatures. The crystallization behavior of mold fluxes was characterized using a SHTT/DHTT (single hot and double hot thermocouple technique). The study discusses the temperature dependence, the influence of the basicity and the non-bridging oxygen per tetrahedra (NBO/T) on the slag properties. The novelty of the work is the systematic characterization of properties of two commercial mold fluxes and the thermal conductivity measurement in the glass transition temperature range
Numerical Modeling of High-Pressure Partial Oxidation of Natural Gas
Get PDFHigh-Pressure Partial Oxidation (HP-POX) of natural gas is one of the techniques in the synthesis gas production by non-catalytic reforming. On the path to emissions reduction, all operating facilities must be optimized to satisfy environmental regulations. In a rapidly changing economic and political environment, technological development from lab-scale to demo-scale, and industrial-scale is no longer feasible. Therefore, new research and design methods must be applied. One of such methods commonly used in science and industry is numerical modeling, which utilizes Computational Fluid Dynamics (CFD), Reduce Order Models (ROMs), kinetic, and equilibrium models.
The CFD models provide details about flow field, temperature distribution, and species conversion. However, the computational effort required to conduct such calculations is significant. The computationally expensive CFD models cannot be effectively used in the reactor optimization. Herewith, other modeling techniques utilizing kinetic and equilibrium models do not provide necessary details for process optimization and can only be used for adjustments of boundary conditions, investigation of specific processes occurring in the reactor, or development of sub-models for CFD.
A numerical investigation was conducted to validate existing CFD models against benchmark experiments. The results reveled that the CFD model is sensitive to modeling parameters, when simulating complex flows where turbulence-chemistry interaction occurs. Moreover, it was shown that the results sensitivity increases along with the oxidizer/fuel inlet velocities ratio. Based on the conducted experiments, the CFD model validation resulted in definition of the modeling parameters suitable for modeling of HP-POX of natural gas.
Based on the validated CFD model, a ROM for HP-POX of natural gas was developed. The model assumes that the reactor consists of several zones characterized by specific conversion processes. Moreover, the model considers inlet streams dissipation upon the injection, and includes several optimization stages that allows model adjustments for any reactor geometry and boundary conditions. It was shown that the developed ROM can reproduce global reactor characteristics at non-equilibrium conditions unlike other ROMs, kinetic, or equilibrium models. Moreover, the validation against CFD results showed that the ROM can correctly account for the \gls{rtd} in the reactors of different geometries and volumes without extensive additional optimization.
Finally, new experiments were designed and conduced at semi-industrial HP-POX facility at TU Bergakademie Freiberg. The experiments aimed to study the influence of different oxidizer/fuel velocities ratios on the reactants mixing and process characteristics at high operating pressures. The high velocity difference between oxidizer and fuel was achieved by injection of High-Velocity Oxidizer (HVO). The experiments showed no significant influence of the HVO on the global reactor characteristics and overall species conversion process. However, the numerical analysis of the experimental results demonstrated that the oxidation zone is affected by the oxidizer inlet velocity, and becomes less efficient in the fuel conversion when the oxidizer/fuel inlet velocities ratio is increased.
In summary, a sophisticated numerical model validation was conducted and sensitivity of the numerical results to the modeling parameters was carefully studied. The novel natural gas conversion technique was experimentally studied. Based on the conducted experiments and numerical evaluation a ROM was developed. The ROM is capable of producing high accuracy results and greatly decreases the computational effort and time needed for reactor development and optimization
Mineralogy and microfabric as foundation for a new particle-based modelling approach for industrial mineral separation
Get PDFMining will remain indispensable for the foreseeable future. For millennia, our society has been exploring and exploiting mineral deposits. Consequently, most of the easily exploitable high-grade deposits, which were of primary interest given their obvious technical and economic advantages, have already been depleted. For the future, the mining sector will have to efficiently produce metals and minerals from low-grade orebodies with complex mineralogical and microstructural properties -- these are generally referred to as complex orebodies. The exploitation of such complex orebodies carries significant technical risks. However, these risks may be reduced by applying modelling tools that are reliable and robust.
In a broad sense, modelling techniques are already applied to estimate the resources and reserves contained in a deposit, and to evaluate the potential recovery (i.e., behaviour in comminution and separation processes) of these materials. This thesis focusses on the modelling of recovery processes, more specifically mineral separation processes, suited to complex ores.
Despite recent developments in the fields of process mineralogy and geometallurgy, current mineral separation modelling methods do not fully incorporate the available information on ore complexity. While it is well known that the mineralogical and microstructural properties of individual particles control their process behaviour, currently widely applied modelling methods consider only distributions of bulk particle properties, which oftentimes require much simplification of the particle data available. Moreover, many of the methods used in industrial plant design and process modelling are based on the chemical composition of the samples, which is only a proxy for the mineralogical composition of the ores.
A modelling method for mineral separation processes suited to complex ores should be particle-based, taking into consideration all quantifiable particle properties, and capable of estimating uncertainties. Moreover, to achieve a method generalizable to diverse mineral separation units (e.g., magnetic separation or flotation) with minimal human bias, strategies to independently weight the importance of different particle properties for the process(es) under investigation should be incorporated.
This dissertation introduces a novel particle-based separation modelling method which fulfills these requirements. The core of the method consists of a least absolute shrinkage and selection operator-regularized (multinomial) logistic regression model trained with a balanced particle dataset. The required particle data are collected with scanning electron microscopy-based automated mineralogy systems. Ultimately, the method can quantify the recovery probability of individual particles, with minimal human input, considering the joint influence of particle shape, size, and modal and surface compositions, for any separation process.
Three different case studies were modelled successfully using this new method, without the need for case-specific modifications: 1) the industrial recovery of pyrochlore from a carbonatite deposit with three froth flotation and one magnetic separation units, 2) the laboratory-scale magnetic separation of a complex skarn ore, and 3) the laboratory-scale separation of apatite from a sedimentary ore rich in carbonate minerals by flotation. Moreover, the generalization potential of the method was tested by predicting the process outcome of samples which had not been used in the model training phase, but came from the same geometallurgical domain of a specific ore deposit. In each of these cases, the method obtained high predictive accuracy.
In addition to its predictive power, the new particle-based separation modelling method provides detailed insights into the influence of specific particle properties on processing behaviour. To name a couple, the influence of size on the recovery of different carbonate minerals by flotation in an industrial operation; and a comparison to traditional methodologies demonstrated the limitation of only considering particle liberation in process mineralogy studies -- the associated minerals should be evaluated, too. Finally, the potential application of the method to minimize the volume of test work required in metallurgical tests was showcased with a complex ore.
The approach developed here provides a foundation for future developments, which can be used to optimize mineral separation processes based on particle properties. The opportunity exists to develop a similar approach to model the comminution of single particles and ultimately allow for the full prediction of the recovery potential of complex ores.:1 Introduction 1
1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.3 State-of-the-art in particle-based separation models . . . . . . . . . . . 11
1.4 Moving forward . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.4.1 Particle data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.4.2 Mathematical tools required for the particle-based separation
model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
1.4.3 Workflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
1.5 Structure of the thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2 The method and its application to industrial operations 23
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2.1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2.2 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.2.1 Assumptions and limitations . . . . . . . . . . . . . . . . . . . . 26
2.2.2 Data structure and required pre-treatment . . . . . . . . . . . . 27
2.2.3 Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.3 Demonstration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.3.1 Artificial test cases . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.3.2 Real case study . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
2.4 Discussion and final considerations . . . . . . . . . . . . . . . . . . . . 39
3 The robustness of the method towards compositional variations of new
feed samples 45
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
3.2 Generalization potential of current Particle-based Separation Model
(PSM) methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
3.3 Case study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.3.1 Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.3.2 Dry magnetic separation tests . . . . . . . . . . . . . . . . . . . 53
3.3.3 Sample characterization . . . . . . . . . . . . . . . . . . . . . . 53
3.3.4 Particle-based separation models . . . . . . . . . . . . . . . . . 54
3.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3.5 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
3.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
4 Flotation kinetics of individual particles 67
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.2 Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
4.2.1 Data collection . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
4.2.2 Cumulative recovery probability . . . . . . . . . . . . . . . . . . 72
4.2.3 Particle-based kinetic flotation model . . . . . . . . . . . . . . . 74
4.3 Demonstration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
4.3.1 Materials and methods . . . . . . . . . . . . . . . . . . . . . . . 75
4.3.2 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
4.4 Discussion and final thoughts . . . . . . . . . . . . . . . . . . . . . . . 80
5 Conclusions and outlook 85
5.1 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
5.2 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Bibliography 8
The influence of physico-chemical surface properties and morphological and topological pore space properties on trapping (CCS) and recovery efficiency (EOR): a micromodel visualization study
Get PDFWe theoretically and experimentally investigate the impact of pore space structure, wettability, and surface roughness on the displacement front, trapping, and sweeping efficiency at low capillary numbers. The microstructure of (i) 2D geologically-realistic media (2D natural sand and sandstone), (ii) a topological 3D-2D-transformation (2D sand analog), and (iii) geometrically representative media (Delaunay Triangulation) were studied over a wide range of wettability from water-wet to oil-wet systems provided by using various fluid-pairs. We observed the transition (compact to fractal) in the displacement front caused by local instabilities identified by Cieplak and Robbins. The trapping efficiency of 2D natural microstructures showed a non-monotonous dependency on wettability, whereas a crossover from no trapping to maximal trapping was observed in 2D patterns of circular grains. For the first time, we compared identical experimental microstructures with simulation, capturing the key elements of the invasion process. We demonstrated that corner flows occur particularly in low-porosity media, where the smaller grain-grain distance hindered the corner-flow bridging. These insights could improve the CO2 geological storage and Enhanced Oil Recovery processes
Analysis of glass beads from the “Roten Schmelzzimmer” in Arnstadt and glass tableware from the Grafschaft Schwarzburg-Sondershausen dating from the 17th and 18th century
Get PDFThis study investigates various glass objects from the 17th and 18th centuries in Thuringia to gain insight into their manufacturing techniques. The objects include glass beads from the Roten Schmelzzimmer and diverse glass objects from the Schwarzburg-Sondershausen collection. The analytical methods include optical microscopy, CT, SEM-EDX, LA-ICP-MS and Raman spectroscopy. The glass beads from the Roten Schmelzzimmer were identified as soda-lime- and high-lead-silicate glasses, which were made using highly pure sands and halophytic plant ashes as a fluxing agent. These recipes are characteristic from the Mediterranean region. The beads were coloured in 11 different colours with copper, cobalt, manganese, iron, and were possibly opacified with salt and tartrate. The analysed glass objects from the Schwarzburg collection were made using different recipes based on potash-lime-silicate glass with high amounts of potash and calcium, and calcinated-bone ashes as a white opacifier, characteristic of central Europe
Reproducible geoscientific modelling with hypergraphs
Get PDFReproducing the construction of a geoscientific model is a hard task. It requires the availability of all required data and an exact description how the construction was performed. In practice data availability and the exactness of the description is often lacking. As part of this thesis I introduce a conceptual framework how geoscientific model constructions can be described as directed acyclic hypergraphs, how such recorded construction graphs can be used to reconstruct the model, and how repetitive constructions can be used to verify the reproducibility of a geoscientific model construction process. In addition I present a software prototype, implementing these concepts. The prototype is tested with three different case studies, including a geophysical measurement analysis, a subsurface model construction and the calculation of a hydrological balance model.:1. Introduction
1.1. Survey on Reproducibility and Automation for Geoscientific Model Construction
1.2. Motivating Example
1.3. Previous Work
1.4. Problem Description
1.5. Structure of this Thesis
1.6. Results Accomplished by this Thesis
2. Terms, Definitions and Requirements
2.1. Terms and Definitions
2.1.1. Geoscientific model
2.1.2. Reproducibility
2.1.3. Realisation
2.2. Requirements
3. Related Work
3.1. Overview
3.2. Geoscientific Data Storage Systems
3.2.1. PostGIS and Similar Systems
3.2.2. Geoscience in Space and Time (GST)
3.3. Geoscientific Modelling Software
3.3.1. gOcad
3.3.2. GemPy
3.4. Experimentation Management Software
3.4.1. DataLad
3.4.2. Data Version Control (DVC)
3.5. Reproducible Software Builds
3.6. Summarised Releated Work
4. Concept
4.1. Construction Hypergraphs
4.1.1. Reproducibility Based on Construction Hypergraphs
4.1.2. Equality definitions
4.1.3. Design Constraints
4.2. Data Handling
5. Design
5.1. Application Structure
5.1.1. Choice of Application Architecture for GeoHub
5.2. Extension Mechanisms
5.2.1. Overview
5.2.2. A Shared Library Based Extension System
5.2.3. Inter-Process Communication Based Extension System
5.2.4. An Extension System Based on a Scripting Language
5.2.5. An Extension System Based on a WebAssembly Interface
5.2.6. Comparison
5.3. Data Storage
5.3.1. Overview
5.3.2. Stored Data
5.3.3. Potential Solutions
5.3.4. Model Versioning
5.3.5. Transactional security
6. Implementation
6.1. General Application Structure
6.2. Data Storage
6.2.1. Database
6.2.2. User-provided Data-processing Extensions
6.3. Operation Executor
6.3.1. Construction Step Descriptions
6.3.2. Construction Step Scheduling
6.3.3. Construction Step Execution
7. Case Studies
7.1. Overview
7.2. Geophysical Model of the BHMZ block
7.2.1. Provided Data and Initial Situation
7.2.2. Construction Process Description
7.2.3. Reproducibility
7.2.4. Identified Problems and Construction Process Improvements
7.2.5. Recommendations
7.3. Three-Dimensional Subsurface Model of the Kolhberg Region
7.3.1. Provided Data and Initial Situation
7.3.2. Construction Process Description
7.3.3. Reproducibility
7.3.4. Identified Problems and Construction Process Improvements
7.3.5. Recommendations
7.4. Hydrologic Balance Model of a Saxonian Stream
7.4.1. Provided Data and Initial Situation
7.4.2. Construction Process Description
7.4.3. Reproducibility
7.4.4. Identified Problems and Construction Process Improvements
7.4.5. Recommendations
7.5. Lessons Learned
8. Conclusions
8.1. Summary
8.2. Outlook
8.2.1. Parametric Model Construction Process
8.2.2. Pull and Push Nodes
8.2.3. Parallelize Single Construction Steps
8.2.4. Provable Model Construction Process Attestation
References
Appendi
Integrierte Bewertung altbergbaulicher Risikoobjekte des Steinkohlenbergbaus der RAG Aktiengesellschaft
Get PDFAktuelle Risikomanagementsysteme verfolgen primär das Ziel, die Vielzahl notwendiger Maßnahmen zur Verwahrung altbergbaulicher Risikoobjekte objektiv und eindeutig zu priorisieren. Unterschiedliche Objektarten werden in separaten Systemen behandelt, auch wenn sich deren Auswirkungen an der Tagesoberfläche regelmäßig überlagen. In der Praxis zeigt sich dies, wenn in großflächigen Maßnahmen viele Objekte gemeinsam bearbeitet werden. Die Limitierung vorhandener interner und externer Ressourcen und die daraus resultierende lange Dauer bis zur Verwahrung aller Risikoobjekte ist der Grund für die Vorgehensweise. Auch wenn die operative Verwahrung schon wegen des Aufwands prioritär erscheint, ist das Ziel die maximale Reduzierung des Gesamtrisikos bei optimaler Nutzung vorhandener Ressourcen. In diesem Beitrag wird eine ganzheitliche Behandlung der altbergbaulichen Risiken vorgestellt. Die Einführung einer linearen Superposition ermöglicht eine modulare Vorgehensweise zur Integration unterschiedlicher Sachverhalte und Objekte in einem System. Neue Erkenntnisse können eingeführt werden, auch wenn sie nur einzelne Risikosachverhalte betreffen. Dabei reichen oft wenige geometrische Parameter, die aus dem markscheiderischen Risswerk oder Sanierungsmaßnahmen abgeleitet werden können. Eine rasterbasierte Berechnung des Risikos aus dem übertägigen Gefährdungspotenzial (= Stärke des Ereignisses) und der Sensibilität der Oberfläche (= Schadensausmaß) ermöglicht es, sinnvolle Bearbeitungsbereiche abzugrenzen. Dabei berücksichtigt eine normalverteilte Nachbarschaftsfunktion die Mobilität der Menschen, um deren Schutz es ja letztlich geht. Die flächennormierte Risikozahl wird zentraler Parameter für eine stets eindeutige Priorisierung. Die im vorliegenden Beitrag vorgestellte Lösung zur ganzheitlichen Bearbeitung altbergbaulicher Risiken wurde ausführlich in der Dissertation (S. Hager, 2022: Integrierte Bewertung altbergbaulicher Risikoobjekte des Steinkohlenbergbaus der RAG AG, TU Freiberg) beschrieben und war Gegenstand eines Vortrags beim Altbergbaukolloquium 2022 in Freiberg