Mathematical Modeling Of Pre And Post Combustion Processes In Coal Power Plant

Coal is a brownish-black sedimentary rock with organic and inorganic constituents. It has been a vital energy resource for humans for millennia. Coal accounts for approximately one quarter of the world’s energy consumption, with 65% of this is energy utilized by residential consumers, and 35% by industrial consumers. Coal operated power stations provide 42% of U.S. electricity supply. The United States hold 96% of coal reserves in North America region, out of which 26% are known for commercial usage. The coal combusted in these power generating facilities requires certain pre-combustion processing, while by-products of coal combustion go through certain post-combustion processing. The application of hydrometallurgical extraction of Rare Earth Elements (REE) from North Dakota Lignite coal feedstock can assist coal value amplification. Extraction of REE from lignite coals liberates REEs and CMs that are vital to electronics, power storage, aviation, and magnets industries. The REE extraction process also reduces the sulfur content of ND lignite coal, along with ash components that foul heat exchange surfaces and can have benefits for post-combustion scrubbing units. When coal is combusted, the exhaust gasses contain carbon dioxide (CO2), sulfur dioxide (SO2), oxides of nitrogen (NOx), water (H2O) and nitrogen (N2). Carbon dioxide comprises approximately 8-10 vol% of the flue gas and is reported to contribute to the greenhouse effect, a primary reason for climate change. Carbon Capture and Storage (CCS) involves of CO2 by use of liquid or solid absorbents to separate CO2 from combustion flue gas. Little data is available on gas-liquid interfacial area correlations in the literature for use of second generation solvents, such as MonoEthanolAmine (MEA), in structured packing absorber columns consisting of thin corrugated metal plates or gauzes, designed to force fluids on complicated paths. While mathematical model development for existing post-combustion carbon capture (PCCC) technologies, such as carbon capture simulations using computational fluid dynamics (CFD) for prediction of mass transfer coefficients is well developed, models describing the behavior of third generation solvents is lacking. Two main research opportunities exist: (i) due to the complex chemistry of coal, there is a requirement for a modeling tool that can account for the coal composition and complex hydrometallurgical extraction processes to assist in designing and sizing pre-combustion REE extraction plants; and (ii) CFD models are required that can capture the mass transfer coefficients of third generation CO2 solvents using structured packing. Two primary hypotheses have been developed to address the research opportunities: (1.) Process modeling of hydrometallurgical extraction of REE provides some theory-based understanding that is complementary to experimental validation and, with the help of chemical kinetics and percentage carboxylation existing in feedstocks, can forecast the efficiency and leachability of other feedstocks, and (2.) A detailed Volume of Fluid (VOF) simulation of coupled mass and momentum transfer problems in small intricate regions of corrugated structured and packed panels placed at 45° angle can be used to predict mass transfer coefficients for third generation solvents by using open-source numerical C/C++ based framework called Open Fields-Operations-And-Manipulations (OpenFOAM). The hydrometallurgical process modeling is developed using METSIM, a leading hydrometallurgical process modeling software tool. The steady state process model provides an overview of REE production along with equipment inventory sizing. The model also has functions to define percentage of organic carboxylic acid bonds present in coal, since, the prior research has identified that the primary association of REE in lignite coal is as weakly-bonded complexes of carboxyl groups, which are targets of the extraction technology. The CFD modeling work is expected to determine critical mass transfer coefficients for CO2 capture using structured packing columns. Further, the developed CFD model and its validity will be tested against experimental data from various industrial and literature sources

Underwater Vehicles

For the latest twenty to thirty years, a significant number of AUVs has been created for the solving of wide spectrum of scientific and applied tasks of ocean development and research. For the short time period the AUVs have shown the efficiency at performance of complex search and inspection works and opened a number of new important applications. Initially the information about AUVs had mainly review-advertising character but now more attention is paid to practical achievements, problems and systems technologies. AUVs are losing their prototype status and have become a fully operational, reliable and effective tool and modern multi-purpose AUVs represent the new class of underwater robotic objects with inherent tasks and practical applications, particular features of technology, systems structure and functional properties

Using MapReduce Streaming for Distributed Life Simulation on the Cloud

Distributed software simulations are indispensable in the study of large-scale life models but often require the use of technically complex lower-level distributed computing frameworks, such as MPI. We propose to overcome the complexity challenge by applying the emerging MapReduce (MR) model to distributed life simulations and by running such simulations on the cloud. Technically, we design optimized MR streaming algorithms for discrete and continuous versions of Conway’s life according to a general MR streaming pattern. We chose life because it is simple enough as a testbed for MR’s applicability to a-life simulations and general enough to make our results applicable to various lattice-based a-life models. We implement and empirically evaluate our algorithms’ performance on Amazon’s Elastic MR cloud. Our experiments demonstrate that a single MR optimization technique called strip partitioning can reduce the execution time of continuous life simulations by 64%. To the best of our knowledge, we are the first to propose and evaluate MR streaming algorithms for lattice-based simulations. Our algorithms can serve as prototypes in the development of novel MR simulation algorithms for large-scale lattice-based a-life models.https://digitalcommons.chapman.edu/scs_books/1014/thumbnail.jp

Globally Optimal Catalysts: Computerbasierte Optimierung von abstrakten katalytischen Einbettungen für beliebige chemische Reaktionen

In the context of inverse design of molecules with desired optimal properties, the long-term goal of this Thesis is to develop a general framework which tackles the design of molecular systems for an optimal catalytic effect onto arbitrary chemical reactions. For any given reaction, an arrangement of an additional molecular framework around this reaction center is sought such that the energetic reaction barrier is lowered as much as possible. As necessary abstraction layer, the so-called globally optimal catalyst (GOCAT) model is introduced, and, furthermore, evolutionary algorithms (EAs) are harnessed as implemented in our global optimization suite for chemical problems, ogolem, which was highly extended to allow for these catalysis optimizations. Starting with a maximally reductionistic approach for studying the non-bonding interactions, electrostatic GOCATs are introduced that consist of arbitrary numbers, distributions and strengths of partial point charges around reacting molecules, mostly surrounding these on a common exposed surface. In the end, two reactions are studied in detail within the general topic of electrostatic catalysis. Some of the initially present model approximations are already sufficiently lifted, still-existing ones are critically assessed and further future extensions to the framework are discussed. Moreover, many method development matters are addressed: They range from optimal shared-memory parallelization, exemplified for global parameter optimization of the reactive force field, ReaxFF, via diversity control parameters for the EAs, applied to a cluster structure optimization problem, to EA operator benchmarks and optimizations of abstract electrostatics.Im Kontext von inversem Design von Molekülen mit optimalen Eigenschaften versucht die vorliegende Arbeit als Langzeitziel eine passende Plattform zu entwickeln, welche das generelle Design molekularer Systeme für einen optimalen Katalyseeffekt auf beliebige chemische Reaktionen projektiert. Für eine gegeben Reaktion soll eine hinzukommende chemische Umgebung komponiert werden, welche die Reaktionsenergiebarriere so weit wie möglich vermindert. Als notwendige Abstraktionsschicht wird das sogenannte Modell des globally optimal catalyst (GOCAT) eingeführt und außerdem kommen Evolutionäre Algorithmen (EAs) zur Anwendung, wie sie bereits in unserem Programmpaket zur Lösung allgemeiner globaler Optimierungsprobleme der Chemie, ogolem, bereitgestellt werden, welches jedoch deutlich für diese Katalyseoptimierungen ergänzt wurde. Angefangen in einem maximal-reduktionistischen Ansatz werden elektrostatische GOCATs erarbeitet, die aus einer beliebigen Anzahl, Verteilung und Stärke von Partialladungen bestehen und rund um die reagierenden Moleküle drapiert werden, meist auf einer gemeinsamen exponierten Oberfläche. Insgesamt werden zwei Reaktionen detailliert untersucht im generellen Kontext von elektrostatischer Katalyse. Einige eingangs vorhandene Modellannahmen werden bereits systematisch verbessert, noch vorhandene kritisch beleuchtet und künftige Erweiterungen auseinandergesetzt. Weiterhin werden unterschiedliche Methodenentwicklungsaspekte angesprochen: Diese reichen von verbesserter Parallelisierung in Mehrprozessorarchitekturen, beispielhaft gezeigt anhand einer globalen Parameteroptimierung des reaktiven Kraftfeldes ReaxFF, über Diversitätskontrollparameter des EAs, illustriert mittels eines Clusterstrukturoptimierungsproblems, bis hin zu EA-Operator-Testevaluationen und allgemeinen abstrakten Elektrostatikoptimierungen

Spectral and High Order Methods for Partial Differential Equations ICOSAHOM 2018

This open access book features a selection of high-quality papers from the presentations at the International Conference on Spectral and High-Order Methods 2018, offering an overview of the depth and breadth of the activities within this important research area. The carefully reviewed papers provide a snapshot of the state of the art, while the extensive bibliography helps initiate new research directions

Physics of Curvature Sensing in Septin Assemblies

Cells rely on their ability to sense and communicate their shape for various functions. While we have gained insights into how cells generate complex shapes, our understanding of how they detect and respond to geometric cues is limited. Septins, GTP-binding proteins that localize to sites of micron-scale membrane curvature, play a crucial role in this process. Through experimental investigations of septin binding at different curvatures and bulk concentrations, we discovered that their preference for curvature is not absolute. Instead, septins exhibit sensitivity to the combinations of membrane curvatures present, suggesting competition between different curvatures for binding. To explain these observations, we developed a kinetic model that connects septin self-assembly and curvature sensing properties. Our results indicate that curvature-sensitive assembly arises from cooperative associations of septin oligomers in solution with bound septins. Therefore, septin curvature sensing is an emergent property resulting from the multi-step, multi-scale assembly of membrane-bound septins. We highlight how curvature preference can be modulated by adjusting physicochemical and geometric parameters involved in septin assembly, such as bulk concentration and available membrane curvatures. While intrinsic material properties typically guide geometry-sensitive assembly in biology, we demonstrate the importance of multi-scale polymer assembly in curvature sensing. Septin assembly is a chemomechanical process that spans several length and time scales. Multi-scale mechanical modeling is required to study the relationship between the molecular structure of the membrane and septin oligomer and the emergent assembly and curvature sensing. Septin assembly in filament scale is in part determined by its hydrodynamic drag. Thus, as a first step towards developing a mechanical model of septin assembly, we consider the simple problem of a single filament moving in a spherical membrane. Using a slender-body formulation, we calculate the translational and rotational resistance of a filament in a membrane surrounded by fluids with different viscosities. For filaments with minimum curvature, we observe confinement effects due to spherical geometry, which become stronger as the filament length-to-membrane radius ratio increases. These confinement flows mildly increase the resistance along the filament's axis and its rotational resistance. However, in the perpendicular direction, the drag increases superlinearly with filament length, ultimately tending to infinity as the length-to-radius ratio approaches $\pi$. Additionally, we find that the filament's curvature affects its parallel motion, inducing asymmetric flow and coupling between parallel and rotational dynamics. This coupling becomes more pronounced with increasing filament length and curvature.Next, we extend the investigation to supported lipid bilayers, specifically a spherical rigid bead coated with lipid bilayers. Using slender body theory, we determine the translational and rotational resistance of a single filament embedded in the outer layer of the supported bilayer membrane and surrounded by Newtonian fluids. We focus on the strong inter-leaflet coupling limit and observe that the resistance in the parallel direction grows linearly with filament length and quadratically with the length for perpendicular and rotational resistance. Scaling arguments and analysis of the velocity fields around the filament support these findings. As inter-leaflet friction decreases, the resistance in all three directions approaches the values observed in bilayer vesicles surrounded by 3D fluid domains on both sides.Doctor of Philosoph

Rock slope instability in alpine geomorphic systems, Switzerland

Faced with the hazard potential and geomorphic importance of rock slopes adjusting to glacier retreat and current climate warming, the motivation of this dissertation is to increase our systemic and process understanding of rock slope instability in alpine geomorphic systems. It is hypothesised that a deeper understanding of rock slope instability can be achieved by thinking and working across scales and accounting for the emergence of non-linear, complex rock slope systems. For this reason, a novel hierarchical methodological approach has been developed. The methodology integrates multivariate modelling and geomorphic field mapping at the valley-scale, rockwall-scale geotechnical, geomorphological and sedimentological field surveys in the Turtmann Valley and Swiss National Park as well as numerical frost cracking modelling and laboratory weathering simulations at the intact rock scale. By means of this multi-method and, most importantly, multiscale systems approach, some progress was made towards current research debates about (i) the key controls of rock slope instability in areas affected by glacier retreat, (ii) associated paraglacial and short-term rockfall activity and (iii) their geomorphic consequences for alpine sediment cascade systems.Felsinstabilitäten in alpinen geomorphologischen Systemen, Schweiz Die Instabilität von Felswänden ist ein komplexes Phänomen das in Zeit und Magnitude variiert. Vor allem in Hochgebirgsregionen sind Felsinstabilitäten von großer Relevanz für die langzeitliche Relieferosion und Landschaftsentwicklung, sowie für die Sedimentproduktion und Effizienz von alpinen Sedimentflüssen. Die damit verbundene Disposition von Sturzereignissen stellt zudem ein ernstzunehmendes Naturgefahrenpotenzial für Mensch und Infrastruktur dar. Untersuchungen zeigen weltweit, und speziell für die Schweizer Alpen, eine Zunahme von Felsinstabilitäten unterschiedlicher Magnituden in den letzten Jahrzehnten. Das komplexe Zusammenspiel von topoklimatischen, kryosphärischen und felsmechanischen Kontrollfaktoren, insbesondere in von Gletscherrückzug betroffenen alpinen Tälern, ist jedoch noch unzureichend verstanden. Folglich stehen nur begrenzt Informationen über die kurz- und langzeitlichen Konsequenzen von Felsinstabilitäten bezüglich Magnituden, Intensitäten und Frequenzen von Sturzprozessen in alpinen Kaskadensystem zur Verfügung. Angesichts dieser Wissenslücken hat diese Doktorarbeit zum Ziel unser System- und Prozessverständnis von alpinen Felsinstabilitäten auf unterschiedlichen Zeit- und Raumskalen zu vertiefen. Ein neuer multiskaliger methodologischer Ansatz wird entwickelt, welcher erlaubt die Skalenabhängigkeit und Emergenz von Felssystemen zu adressieren. Die Arbeit umfasst fünf empirische Studien auf unterschiedlichen räumlichen und zeitlichen Skalen mit Untersuchungsgebieten im Turtmanntal (Schweizer Waliser Alpen) und Schweizer National Park. Auf der größten und längsten Skale untersucht diese Arbeit Hauptkontrollfaktoren für die raumzeitliche Aktivität von Felsinstabilitäten in alpinen Tälern seit dem letzten Glazialen Maximum. Zum ersten Mal in der Sturzprozessforschung wird ein Random Forest Klassifikationsalgorithmus angewandt und durch die Kombination mit einem Hauptkomponenten-basierten, logistischen Regressionsmodell weiter entwickelt. Die Modellkombination zeigt auf, dass Permafrostdegradation im Laufe des Gletscherrückzugs einer der wichtigsten Kontrollfaktoren für die Instabilität entgletscherter Felswände darstellt. Mit Hilfe eines ergodischen Ansatzes werden drei Szenarien paraglazialer Felsanpassung entwickelt, welches nichtlineare tektonische und strukturelle Konditionierungen von Permafrostwänden berücksichtigt. Die Arbeit liefert zudem quantitative und qualitative Beweise für die geomorphologische Signifikanz von Felsinstabilitäten für Sedimentkaskaden in alpinen Einzugsgebieten. Die Kombination aus einem GIS-basierten Konnektivitätsmodell und einer detaillierten geomorphologischen Feldkartierung ermöglicht es Sedimentflüsse von instabilen Felswänden zum fluvialen System zu identifiziert und im Hinblick auf ihre Effizienz zu bewerten. Die feld- und modellierungsbasierten Beobachtungen zeigen eine Dominanz von Sturzprozesse kleiner bis mittlerer Magnitude. Allerdings wird deutlich, dass aktuell ein Drittel des gespeicherten Sturzmaterials aufgrund der glazialen Talmorphometrie vom Hauptkaskadensystem entkoppelt ist. Auf der Skale individueller Felswände analysiert diese Arbeit die Ursache-Wirkung Beziehung zwischen Felsverwitterung, Felsinstabilität sowie Materialspeicherung auf Schutthalden in drei vergletscherten Hängetälern. Ein neuer holistischer Ansatz wird vorgestellt, welcher abduktive Schutthaldenuntersuchungen mit deduktiven geotechnischen Kartierungen an Felswänden, einem zweijährigen Felstemperaturmonitoring und numerischer Frostverwitterungsmodellierung integriert. Dieser integrative Ansatz zeigt auf, dass die Komplexität aus Kluftabstand, der vorgegebenen Kinematik aus Haupttrennflächen sowie der tiefenvariierenden Intensität saisonaler Eissegregation wesentlich das jährlich-dekadische Frequenz-Magnituden Spektrum von Sturzprozessen steuert sowie, in Kombination mit Permafrostdegradation, die langzeitliche Variabilität von Sedimentproduktion und Formeigenschaften von Schutthalden kontrolliert. Auf der Skale des intakten Fels widmet sich diese Arbeit der Frage nach der individuellen und synergetischen Verwitterungseffizienz hochfrequenter thermaler Zyklen und täglicher Eiskristallisation in Glimmerschiefer geringer Porosität. Ein neuartiges zweiphasiges Laborexperiment liefert Evidenzen für mikroskalige, strukturabhängige Felsermüdung in Folge wiederholter Frostzyklen, insbesondere in Felsproben, welche zuvor einer Phase thermalen Stresses ausgesetzt waren. Die Langzeitmessungen zeigen sowohl positive als auch negative Feedbackeffekte im Laufe verändernder mechanischer Felseigenschaften. Diese Beobachtungen haben Implikationen für aktuelle Forschungsdebatte über die Rolle subkrtitischer Verwitterungsmechanismen für oberflächennahe Felsinstabilitäten. Diese Arbeit hebt hervor, dass geomorphologische Forschung dringend mehr Aufmerksamkeit auf die Quellgebiete in alpinen Systemen, also Felswände und ihre inhärenten Systemeigenschaften, richten muss. Zudem zeigen die Befunde dieser Arbeit auf, dass die Instabilität von Felswänden eine Skalenfrage ist. Jede räumliche und zeitliche Skale ist mit unterschiedlichen Kausalzusammenhängen und Erklärungen verbunden hinsichtlich Hauptkontrollfaktoren, raumzeitlicher Sturzprozessaktivität und geomorphologischen Effekten für Sedimentkaskaden. Um diese Skalenabhängigkeit und Nichtlinearität von Felssystemen zu adressieren, liefert diese Arbeit verschiedene praktische und philosophische Lösungsansätze für zukünftige Forschung

Globalistics and Globalization Studies: Global Transformations and Global Future

The present volume is the fifth in the series of yearbooks with the title Globalistics and Globalization Studies. The subtitle of the present volume is Global Transformations and Global Future. We become more and more accustomed to think globally and to see global processes. And our future can all means be global. However, is this statement justified? Indeed, in recent years, many have begun to claim that globalization has stalled, that we are rather dealing with the process of anti-globalization. Will not we find ourselves at some point again in an edifice spanning across the globe, but divided into national apartments, separated by walls of high tariffs and mutual suspicion? Of course, some setbacks are always possible, because the process of globalization cannot develop smoothly. It is a process which is itself emerging from contradictions and is shaped by a new contradiction. They often go much further than underlying systemic changes allow. They break forward, as the vanguard of a victorious army, and then often meet resistance of various social and political forces and may suddenly start to roll back just at the moment when everyone expects their further offensive. We believe that this is what is happening with globalization at present. The yearbook will be interesting to a wide range of researchers, teachers, students and all those who are concerned about global issues