87 search hits
-
Organization of Paramagnetic and Nonmagnetic Colloidal Particles in Ferrofluid
(2012)
-
Ayan Ray
- In this thesis, I have studied magnetic dipolar interactions between paramagnetic and nonmagnetic colloidal particles immersed in a magnetic fluid under the influence of an external time dependent magnetic field. These interactions play an important role in colloidal self-assembly. As a result, of these interactions different forms of anisotropic superstructures evolve in 2-Dimension and 3-Dimension during the self-assembly process. The time dependent external magnetic field is an important controlling parameter for the self-assembly process. The interactions leads to a specific equilibrium positions of the paramagnetic and nonmagnetic particles with specific orientations of the magnetic moments. Three different colloidal systems immersed in ferrofluid with external time dependent magnetic field have been investigated. In each of them the effect of inter dipolar interactions on the particles is discussed. Three systems are arranged and discussed in three separate chapters. In chapter 3, an attempt has been made to study the diffusion of particles in a colloidal flower system and compare the diffusion of the petals of the flower with other single file diffusion in 1-dimension. Beside the long-range interactions, in chapter 4, we have studied the strength of the systems and order of phase transition taking place due to core size effects of self-assembled flower shaped magnetic colloidal clusters and diamagnetic clusters in a precessing magnetic field. In chapter 5, different anisotropic assemblies and colloidal phases are studies as a function of the composition mixture of paramagnetic and diamagnetic particles in an external time dependent magnetic field.
-
Copper exposure of freshwater mussels (Anodonta anatina): Some physiological effects
(2012)
-
Andhika Puspito Nugroho
- Copper (Cu), a transition metal, has the tendency to increase in its concentration in freshwater ecosystems over natural levels, due to industrial and other anthropogenic sources. In water, copper can exist in dissolved form or associated with suspended food particles. Freshwater mussels living at the interface of the free-flowing water and the sediment phase can take up copper directly from the water or by consumption of lower trophic level organisms laden with copper. For mussels, copper is essential at low concentration as cofactor of metalloenzymes involved in growth regulation and development, but it may be toxic at higher levels by disturbing calcium (Ca) homeostasis. The duck mussel Anodonta anatina is a freshwater species found in abundance in limnic and lotic European ecosystems and is used as test organism in ecotoxicological studies. The potential involvement of Cu in the general decline of many European freshwater mussel species is the major motivation for this work. This research aims to study the relevance of Cu exposure pathways on its uptake, distribution, bioaccumulation, and elimination in the freshwater mussel A. anatina and its various potential physiological impacts. The work is started with raising Cu-loaded algae using the stable isotope 63Cu as marker for feeding of mussels without affecting the nutritional value of the algal food. In these latter experiments, mussels are exposed to 63Cu via water or via food to investigate the relative importance of Cu uptake to its distribution and accumulation among the mussel’s organs. Its consequences on calcium homeostasis, soluble carbohydrate and protein levels in various tissues, metallothionein induction, glutathione levels, activities of antioxidative enzymes and glutathione reductase, and on lipid peroxidation are examined. In the algal experiment, Parachlorella kessleri is grown at six 63Cu concentrations (0, 5.9, 11.7, 23.5, 47, and 94 µmol L-1) for 4 days, starting from day 3. When exposed to Cu at a level of up to 6 µmol L-1, P. kessleri is largely unchanged in its nutritional values; so this concentration is used to grow 63Cu-carrying food for mussel experiment. Concentrations above 6 µmol L-1 decrease significantly in the algal growth and alter the other physiological parameters. Three groups of 21 mussels each are used, one as control and two for exposure, receiving copper as the stable isotope 63Cu via the water at 0.3 µmol L-1 or via the food (1.5 mg L-1 freeze-dried Cu-loaded algae, equivalent to 0.06 µmol L-1 Cu) for 24 days, followed by 12 days of depuration. For analysis, three mussels each are taken randomly from every group at days 0, 6, 12, 18, 24, 30, and 36. The mussels are anaesthetized and hemolymph and extrapallial fluid are sampled before the mussels are dissected into gills, mantle, kidney, digestive gland, foot, adductors, intestines, and the remainder (gonads, heart, and labial palps). During copper exposure, the levels of exogenous copper (63Cu) and total Cu increase in all body compartments. Uptake via the water leads to higher Cu levels than via the food, but in relative terms food uptake is more efficient taking the five-fold lower nominal concentration of copper into consideration. Upon exposure via the water, the metal is compartmentalized mainly in the mantle, the gills, and the digestive gland, upon exposure via the food the major recipients are the digestive gland and the intestines. Upon depuration for two weeks, copper is quickly but not completely eliminated. Simultaneously with increasing Cu levels, Ca levels are increased in all body compartments, accompanied by decreases in soluble carbohydrates and proteins in the gills, mantle, digestive gland, and kidney. At the same time, Cu exposure results in increases in malondialdehyde levels, decreases in glutathione levels, strong increases in metallothionein levels, and changes in the activities of the antioxidative enzymes superoxide dismutase, catalase, and glutathione peroxidise, and of glutathione reductase in the gills, mantle, digestive gland, and kidney. During depuration, most parameters tend to normalize but do not return to control values. In conclusion, the overall pictures suggest that the considerable physiological stress elicited by low-level copper exposure may contribute to the factors involved in the decline of many European freshwater mussels.
-
Structure and Reactivity of Terrestrial and Extraterrestrial Pyrrhotite
(2012)
-
Dennis Harries
- Pyrrhotite (Fe1-xS) is a non-stoichiometric iron monosulfide common in terrestrial rocks, ore deposits, and many extraterrestrial materials. The non-stoichiometry due to metal vacancies relates to a variety of composition-dependent crystallographic superstructures, but little of the existing structural and microstructural complexity has been explored yet. This thesis investigates the occurrences and nature of pyrrhotite superstructures, examines the related nano- and microstructural phenomena, and explores their effects on chemical reactivity. The goal is to comprehend the relations of the nanoscale real structure of pyrrhotite to its physicochemical properties. A central tool in these studies is analytical transmission electron microscopy (TEM), which has been extensively used to study terrestrial and extraterrestrial samples. In three studies, published or submitted as scientific research articles, it is shown that structural complexity of pyrrhotites is a widespread feature in terrestrial and extraterrestrial materials and is strongly interrelated with its physicochemical properties and environments of formation and alteration. A new model based on translation interface modulation is being introduced to provide a realistic description of the structural state of natural NC-pyrrhotites. Novel insights into the thermodynamically stable phase assemblages in the Fe-S system at ambient temperatures are presented and the crystallography and connected thermochemistry of pyrrhotites are deployed to reach new conclusions about the petrogenetic history of chondritic meteorites and the alteration processes they were involved in. Finally, an experimental alteration study reveals for the fist time quantitatively that the vacancy superstructures and anisotropy of pyrrhotites have tremendous effects on their kinetic behaviors during dissolution under acidic and oxidizing conditions. Intrinsic reactivity differences between 4C- and NC-pyrrhotite are clearly resolved and discusses in the framework of the newly established structure model.
-
Kinetics and Reaction Engineering Aspects of Syngas Production by the Heterogeneously Catalysed Reverse Water Gas Shift Reaction
(2012)
-
Rajabhau Bajirao Unde
- As a contribution to the development of a process for CO2 utilisation and/or syngas production, the catalytic hydrogenation of CO2 using commercial Ni/Al12O19 and Al2O3 catalysts was studied. The experiments were performed in a down-flow fixed bed quartz reactor at atmospheric pressure. The reverse water gas shift (RWGS) reaction was examined in both the forward and reverse direction. In addition to these experiments, the consecutive reaction of CO to CH4 was also studied. The results indicate that the Ni/Al12O19 and the Al2O3 catalyst used are suitable to convert CO2 with H2 to CO and H2O at temperatures higher than 800 °C where no CH4 formation was observed. Kinetic data was obtained by systematic variation of the reaction conditions. These data were used to develop a model which explains the intrinsic and the effective kinetics (influence of internal and external diffusion) of the respective reaction. Based on the kinetic data of the RWGS reaction over the Ni/Al12O19 and the Al2O3 catalysts, technical fixed-bed reactors were simulated for the production of syngas, using a one-dimensional reactor model. The model takes into account the intrinsic kinetics, the internal and external mass transfer and the concentration and temperature gradients only in axial but not in radial direction. Two cases were considered as attractive for a technical RWGS process, isothermal and adiabatic operation in a fixed-bed tubular reactor. The differential equations for mass and heat transfer were solved by using the program Berkeley Madonna. The simulated temperature and conversion profiles within the reactor are presented. Pressure drop as well as reactor size required in a technical adiabatic fixed bed RWGS reactors were also estimated for both catalysts.
-
Die doppelte Triade: Wotan - Loge - Erda/Wagner - Freud - Butler
(2012)
-
Simone Fohr-Manthey
- Dieser Aufsatz unterzieht Richard Wagners Rheingold einer Relektüre, die sich auf die darin enthaltenen Momente moderner Konzepte hin-sichtlich Inhalt und Handhabung der gesanglichen Disposition konzentriert. Diese sind, erstens, die Destabilisierung des Ich-Begriffes und, zweitens, Freuds Konzept der drei Instanzen (Ich, Es und Über-Ich) die das Selbst beherrschen. Einen dritten Schwerpunkt macht Wagners Idee eines androgynen Systems jenseits des Dualismus von Männlichkeit/Weiblichkeit aus, wie es von Judith Butler beschrieben wird. Eine Analyse der dramatischen Funktion und Gesangspartien – in Hinblick auf die oben genannten Prämissen – der Charaktere Wotan, Loge und Erda soll dabei aufzeigen, ob und wie Richard Wagner, ein Musikdramatiker des 19. Jahrhunderts, als Protomodernist und somit als Wegbereiter der Moderne gewertet werden kann.
-
Richard Wagner, Louis de Fourcaud, and a Path for French Opera in the 1880s
(2012)
-
Marie-Hélène Benoit-Otis
- In a much-quoted interview with Richard Wagner conducted by the French critic Louis de Fourcaud in 1879, and published in different versions in 1880, 1884, and 1886, the composer allegedly advised the French to write operas drawing on their own legendary sources. Contemporary works such as d’Indy’s Fervaal, Chausson’s Le Roi Arthus, and Massenet’s Esclarmonde suggest that Fourcaud’s interview did indeed have a profound impact on the Wagnerian movement in France. However, a close examination of the sources reveals that his text owes much less to Wagner than scholars have previously assumed: in fact, evidence suggests that the most important part of the interview (that is, the advice to French composers) was added by Fourcaud himself after Wagner’s death.
-
Der Fliegende Holländer in der Inszenierung von Christoph Schlingensief, Manaus 2007. Eine Annäherung anhand von Dokumenten, Aufzeichnungen und Gesprächen mit Mitarbeitern
(2012)
-
Anna-Catharina Gebbers
- Folgende Betrachtung von Christoph Schlingensiefs Inszenierung von Der Fliegende Holländer 2007 in Manaus basiert sowohl auf der Sichtung einer filmischen Dokumentation der Aufführung und filmischen und textbasierten Zusatzmaterialien als auch auf Interviews mit direkt beteiligten Mitgliedern aus dem Team von Christoph Schlingensief. Damit wird einerseits der grundsätzlichen Problematik von Aufführungsanalysen und zum anderen Schlingensiefs vielschichtigem Vorgehen Rechnung getragen. Diese Herangehensweise kommt, so meine These, der Christoph Schlingensiefs Arbeitsweise näher als der Versuch einer kongruenten Nacherzählung, die alle Unterschiede zum Wohle einer zusammenführenden Betrachtung verschleift: Auch Schlingensiefs Inszenierungen waren auf eine Zersplitterung der Perspektive angelegt – ermöglicht durch ein oftmals sehr präzises Skript, das verschiedenste Inszenierungselemente und ortspezifische Charakteristika gleichwertig zum Einsatz brachte.
-
Michael Haverkamp, Synästhetisches Design. Kreative Produktentwicklung für alle Sinne, München, Wien: Hanser 2009
(2012)
-
Stefan Strötgen
- Angesichts des Titels mag eine Vorstellung dieses Buches hier zunächst etwas deplatziert anmuten, scheint es doch vor allem für Produktdesigner verfasst zu sein. Tatsächlich ist dies auch die primäre Zielgruppe der Publikation von Haverkamp, der selbst Ingenieur und im Automobildesign der Ford-Werke in Köln tätig ist. Die Relevanz für den Fachbereich Musik und Performance, der Musik als Teil einer mit allen Sinnen erlebten Welt betrachtet, erschließt sich jedoch recht schnell angesichts des erklärten und recht ambitionierten Ziels, "alle Möglichkeiten der Verknüpfung von Sinnesempfindungen zusammenzustellen".
-
Zur so genannten gegengeschlechtlichen Besetzungspraxis. Nebst einer Besprechung der aktuellen Publikationen von Knaus sowie Beghelli und Talmelli
(2012)
-
Saskia Maria Woyke
- Das Thema der Singstimmen beschäftigt die Musikwissenschaft spätestens seit dem so genannten "performative turn" der Geisteswissenschaften vor nunmehr fast zwei Jahrzehnten intensiver denn je. Positiverweise aber verlagert sich das Interesse auf die Stimmen, die Vokalprofile selbst, in Verbindung mit den Rollenprofilen, ebenso wie auf die Frage der Geschlechterbilder, die in ihnen übertragen werden, statt in vornehmlich biographisch orientierten Angaben über die Sängerinnen und Sänger zu verharren. Diese eher späte Entwicklung hat mit der Schwierigkeit der allgemeinen wie wissenschaftlichen Beschreibung einer aufgezeichneten oder gar verklungenen Stimme zu tun. Gleichzeitig sind die Geschlechterdiskurse im Umfeld der Stimmaufführungen verschiedener Epochen, Jahrzehnte und Orte, jedenfalls bis ca. 1750 trotz bemerkenswerter Ansätze seitens der Geschlechterforschung noch nicht gänzlich aufgearbeitet, was zur Folge hat, dass die Stimmforschung, die die Kategorie des Geschlechts einbeziehen will, hier oft nicht nur mit einer, sondern zwei nahezu Unbekannten operieren muss. Eine Aufzählung der entsprechenden neuesten Literatur zum Thema wird im Folgenden unterlassen, würde sie doch den Raum überschreiten oder aber als exemplarische Auswahl Wertvolles auslassen.
-
Editorial 2012/3: Über Wagner
(2012)
-
Anno Mungen
- Das Jahr 2013 wird musikalisch ganz im Zeichen Richard Wagners stehen. Die Klassikbranche, die Feuilletons und die Wissenschaft feiern dann den 200. Geburtstag des Bayreuther Meisters. Unser vorliegendes Heft dürfte eine der ersten Publikationen sein, die sich mit Wagner im Kontext dieses Jubiläums beschäftigt. Viele weitere werden folgen. Dieses Heft ist Teil der Initiative www2013:(WagnerWorldWide 2013), die von Thurnau ihren Ausgang nahm: Mit der Ringvorlesung, die an der Universität Bayreuth im Wintersemester 2011/2012 stattgefunden hat, wird die Stafette im Juni über Shanghai (China) nach Bern (Schweiz), dann zur University of South Carolina in Columbia (South Carolina, USA) und schließlich, im Dezember 2013, wieder zurück nach Thurnau weitergereicht.
