Although a considerable amount of research exists on geometrical aspects of 5-axis flank milling, the dynamics of this efficient milling operation have not yet been given proper attention. In particular, investigating machining chatter in 5-axis flank milling remains as an open problem in the literature. The axial depth of cut in this operation is typically quite large, which makes it prone to machining chatter. In this thesis, chatter in 5-axis flank milling is studied by developing analytical methods of examining vibration stability, generating numerical simulations of the process, and conducting experimental investigations. The typical application of 5-axis milling includes the machining of thermal resistant steel alloys at low cutting speeds, where the process damping dominates the machining vibration. The results of experimental study in this thesis showed that the effect of process damping is even stronger in flank milling due to the long axial engagement. Accordingly, the first part of the thesis is devoted to studying process damping, and in the second part, the modeling of chatter in flank milling is presented. Linear and nonlinear models have been reported in the literature that account for process damping. Although linear models are easier to implement in predicting stability limits, they could lead to misinterpretation of the actual status of the cut. On the other hand, nonlinear damping models are difficult to implement for stability estimation analytically, yet they allow the prediction of “finite amplitude stability” from time domain simulations. This phenomenon of “finite amplitude stability” has been demonstrated in the literature using numerical simulations. In this thesis, that phenomenon is investigated experimentally. The experimental work focuses on uninterrupted cutting, in particular plunge turning, to avoid unduly complications associated with transient vibration. The experiments confirm that, because of the nonlinearity of the process damping, the transition from fully stable to fully unstable cutting occurs gradually over a range of width of cut. The experimental investigation is followed by developing a new formulation for process damping based on the indentation force model. Then, the presented formulation is used to compute the stability lobes in plunge turning, taking into account the effect of nonlinear process damping. The developed lobes could be established for different amplitudes of vibration. This is a departure from the traditional notion that the stability lobes represent a single boundary between fully stable and fully unstable cutting conditions. Moreover, the process damping model is integrated into the Multi-Frequency Solution and the Semi Discretization Method to establish the stability lobes in milling. The basic formulations are presented along with comparisons between the two approaches, using examples from the literature. A non-shallow cut is employed in the comparisons. Assessing the performance of the two methods is conducted using time domain simulations. It is shown that the Semi Discretization Method provides accurate results over the whole tested range of cutting speed, whereas higher harmonics are required to achieve the same accuracy when applying the Multi Frequency Solution at low speeds. Semi Discretization method is modified further to calculate the stability lobes in flank milling with tools with helical teeth. In addition to the tool helix angle and long axial immersion, the effect of instantaneous chip thickness on the cutting force coefficients is considered in the modified formulation of Semi Discretization as well. Considering the effect of chip thickness variation on the cutting force coefficients is even more important in the modeling of 5-axis flank milling, where the feedrate, and consequently the chip thickness, varies at each cutter location. It also varies along the tool axis due to the additional rotary and tilt axis. In addition to the feedrate, the tool and workpiece engagement geometry varies at each cutter location as well. The actual feedrate at each cutter location is calculated by the dynamic processing of the toolpath. The tool and workpiece engagement geometry is calculated analytically using the parametric formulation of grazing surface at the previous and current passes. After calculating the instantaneous chip thickness and tool/workpiece engagement geometry, they are integrated into the Semi Discretization Method in 5-axis flank milling to examine the stability of vibration at each cutter location. While the presented chatter analysis results in establishing stability lobes in 3-axis flank milling, it results in developing a novel approach in presenting the stability of the cut in 5-axis flank milling. The new approach, namely “stability maps”, determines the unstable cutter locations of the toolpath at each spindle speed. The accuracy of established 3-axis flank milling stability lobes and 5-axis stability maps is verified by conducting a set of cutting experiments and numerical simulations.

This study includes examination of the machinability characteristics of two medium carbon steel types (SAE 1040 and SAE 1050) as a result of spherodizing treatment. Both steel types were handled into four categories according to their spherodizing treatment parameters (temperature and time). Microstructural investigation, hardness and ultrasonic sound velocity measurement (with both longitudinal and transverse waves) of these steels were performed, and effect of applied heat treatments on microstructure, hardness and ultrasonic sound velocity was investigated. Pulse-echo method has been used for ultrasonic sound velocity measurements, and measurements were performed with 5 and 10 MHz longitudinal and 5 MHz transverse wave probes. Tool life criterion was used for determining the machinability characteristics of the steels. For this purpose, flank wear land measurements were performed on the cutting tools. Results have showed that, by appliying heat treatment it is possible to change the microstructure, hardness, ultrasonic sound velocity and machinability characteristics of a steel.

Banana holes are a common karst feature of The Bahamas and several theories have been presented to explain their origin. The current model for banana hole formation places their dissolution at the mixing zone at the top of the fresh water lens. This theory is based on the observation that banana holes are often found in the interior of islands, far from the dissolutionally aggressive fresh water lens margin. This study proposes that banana holes form at the lens margin as it follows a prograding strandplain. Spatial observations show that banana holes appear to be associated with low inland ridges and their orientation appears to correlate with features found on modern shorelines. Bedding features such as herringbone cross beds and back-beach rubble found in banana hole wall rock point to a progradational environment of deposition for banana hole host rock.

A geodatabase and a data management program have been created to store and manipulate cave and karst feature data from the Bahamas. A geographic information system was used to recognize any spatial patterns in the cave and karst data from San Salvador Island. Elevation data for banana holes, vadose pits and flank margin caves were obtained from a digital elevation model and are consistent with values predicted by the Carbonate Island Karst Model. The slope and aspect of the hill on which a flank margin cave is found showed no relationship to cave sizes and shapes, emphasizing the hypogenic nature of flank margin caves. The digital elevation model further demonstrated the position of lakes on San Salvador Island during the last interglacial (OIS 5e) highstand, and the lack of flank margin caves along the shores of these lakes provides evidence for a paleoclimate on San Salvador Island similar to today?s.

Rota Island, the southernmost island in the Commonwealth of the Northern Mariana Islands in the western Pacific, has the types of caves previously documented on the other limestone mantled islands in the Mariana Arc that have been investigated for caves: Aguijan, Guam, Tinian and Saipan. Caves developed at the edge of the fresh-water lens by zones of enhanced carbonate dissolution produced by fresh-water/salt-water mixing are most common. Among these mixing zone caves, flank margin caves dominate. Flank margin caves were found singly and in extensive horizons representing significant sea-level still stands. However, another type of mixing zone cave was found on Rota in numbers not documented on neighboring islands. Mixing zone fracture caves, apparently formed as zones of enhanced dissolution, produced fresh-water discharging from the lens along fractures, migrated vertically as sea-level changed. Some mixing zone fracture caves on Rota are developed in clusters from two to four caves. The mixing zone caves of Rota reflect the interaction of eogenetic limestone, glacioeustasy, local tectonics and enhanced carbonate dissolution via mixing of disparate waters. The development of mixing zone caves on Rota is in agreement with the Carbonate Island Karst Model (CIKM). Rota has a few caves developed along the contact between limestone and the insoluble volcanic rock that makes up the core of the island. The most important of these is Water Cave, a large spring that is the source for most of the municipal water on Rota. Rota also two extensive zones of vertical fissures developed along bedrock fractures; Fissure City and As Mundo Fissure Zone. In addition, Rota has one cave apparently developed along a fault; Gagani Cave. Some of the caves documented on Rota are difficult to classify and warrant further investigation.

Abaco Island is located on Little Bahama Bank at the northwestern extent of the Bahamian Archipelago. Karst features on Abaco include: flank margin caves, karren, blue holes, pit caves, banana holes, and cone karst. As part of this study all known flank margin caves on Abaco were GPS located and surveyed. The presence and locations of the other karst features were recorded as part of the karst inventory of Abaco. The cone karst is of particular interest because cone karst has not been documented on other Bahamian islands. These cones form from the dissection of an eolianite ridge due to karst, fire, and vegetative processes. Tafoni-like recesses, originally believed to be high flank margin caves, were formed during cliffing of an eolianite ridge during the OIS 5e highstand. The geologic evolution of representative depositional sequences on Abaco fits within the accepted Bahamian stratigraphy.

Im Zuge eines Forschungsprojektes werden Möglichkeiten untersucht, die Schallemissionen eines Bühnenpodiums unter einen für Zuschauer wahrnehmbaren Schalldruckegel zu reduzieren. Daraus ergibt sich u.a. die Motivation, die Schalleistung für spezifische Antriebe zu bestimmen um bühnen- und antriebsspezifische Lösungskonzepte zur Schallemissionsreduzierung zu entwickeln. Zur Ermittlung entsprechender Lösungen werden an erster Stelle die Geometrien der antriebsspezifischen Zahnradpaarungen in einem CAD-Modell dargestellt. Erlauben die Flankengeometrien die Abbildung eines Überrollvorganges mit ununterbrochenem Zahnflankenkontakt, können die Zahnradmodelle weiterführend in einer nichtlinearen FEM-Simulation verwendet werden. Ziel dieser nichtlinearen Simulation ist die Bestimmung der aus dem Überrollvorgang resultierenden Erregerkräfte im Zeitbereich. Anschließend ist die Übertragung dieser Kräfte in den Frequenzbereich möglich, was nachfolgend eine harmonische Simulation sowie final die Feststellung der antriebsspezifischen Schallleistung erlaubt.

På Kanarieön La Palma finns sprickzonen och vulkanen Cumbre Vieja. Under ett vulkanutbrott år 1949 bildades ett förkastningssystem längs vulkanens västra sida som skulle kunna vara ett förstadium till en framtida kollaps av vulkanen. Denna kollaps skulle kunna leda till bildandet av en tsunami när kollapsmaterial rasar ner i havet likt ett jordskred. Tsunamin kan komma att spridas över stora delar av Atlanten och i olika grad påverka de omkringliggande kontinenterna. Det finns olika teorier om hur stort jordskredet kommer att bli och om det kommer att ske successivt eller kollapsa som en enda enhet. I detta arbete studeras fyra kollapsscenarier med volymer av 20 km3, 40 km3, 80 km3 och 450 km3 närmare. Utifrån dessa volymer skapas riskanalyskartor i GIS över ön Teneriffa och New Yorks storstadsområde som visar hur långt över land tsunamin når vid de olika kollapsscenarierna. Dessa kartor jämförs sedan med markanvändningskartor över Teneriffa och New Yorks storstadsområde. Trots att tsunamivågen kan bli mycket hög vid Teneriffas kust kommer stora delar av ön att undkomma tsunamin, vilket bl.a. beror på öns höga höjd över havet. Då de flesta byggnader är belägna vid kusten innebär det att många människor ändå riskerar att drabbas. New Yorks storstadsområde är istället lågt beläget, vilket bidrar till att många kustnära områden kommer att drabbas trots att våghöjden har avtagit väsentligt. Då detta område är mycket tätbefolkat kan en tsunami därför leda till en stor påverkan. / On the Canary Island La Palma there is a volcanic ridge called Cumbre Vieja. During an eruption in 1949 a fault system was formed along the western flank of the volcano that can be an early stage of a future flank collapse of Cumbre Vieja. During this collapse a large volume of rock material will fall into the ocean like a landslide, which could lead to the formation of a tsunami. The tsunami could spread over large parts of the Atlantic Ocean and to varying extent affect the surrounding continents. There are different theories of how big the landslide will be and if it will collapse gradually or as a coherent block. In this study four collapse scenarios with different volumes, 20 km3, 40 km3, 80 km3 and 450 km3, are studied more closely. Based on these volumes, vulnerability maps are created in GIS covering the island Tenerife and the New York metropolitan area. The maps show the land reach of the tsunami for each of the collapse scenarios. These maps are thereafter compared with land use maps over Tenerife and the New York metropolitan area. Despite the high amplitude of the tsunami wave at the coast of Tenerife, large parts of the island will remain unaffected by the tsunami. This is due to, among other things, the high altitude of the island. However, most buildings are located along the coast, which means that many people are at risk. The New York metropolitan area has, on the other hand, low altitude which is one explanation why many coastal areas will be affected despite the significant decrease in tsunami wave height. A tsunami would have a major impact due to these areas being densely populated.

This thesis offers a comparative historical analysis of sub-state violent contention in Quebec and Corsica. It focuses specifically on the Front de Libération du Québec (FLQ) and the Fronte di Liberazione Naziunale Corsu (FLNC), in 1963 to 1971 and 1976 to 1990, respectively. The thesis argues that the FLQ and the FLNC sought to extend radical ideological space to promote independence in order to achieve revolutionary social and economic change through campaigns of violence and kidnappings. Theoretically, the thesis draws on the contentious politics and social movements literatures, which it notably combines with Radical Flank Effect (RFE). RFEs are interactive processes that aim to map the beneficial and/or detrimental impact of radical group action on moderate groups. Whilst commonly used to understand the political outcomes of social movements, RFE is used in this thesis in conjunction with social movement literature to compare the relationship between these violent movements and their more moderate opponents. To understand the internal dynamics of these movements, I have identified four key elements of contrast: membership, ideology, network structure and strategy. I draw on, for example, McAdam, Tarrow and Tilly's (2001) mobilization method, which aids an understanding of membership and ideology by framing the interaction amongst challengers, their opponents and the media. This thesis seeks to understand FLQ and FLNC mobilization in light of the aim to shape and develop radical ideological space in the sub-states of Quebec and Corsica. It draws on an extensive study of archival data that includes police reports that have only recently been made available in Canada, transcripts of court cases, newspapers, and an interview with a former member of the FLNC, as well as secondary sources. The central orienting question is: what explains the contrasting patterns of sub-state violent contention in Quebec and Corsica? More specifically, why did the FLQ dissolve in 1971, yet the FLNC continued its violent trajectory, albeit less political and nationalist, until 2014? The FLQ and the FLNC differently subscribed to Marxism and postcolonialism. The FLQ was committed to a Marxist program of revolutionary change, and this commitment was shared by the FLNC until the collapse of communism in central and Eastern Europe in 1989. FLQ members considered themselves 'urban revolutionaries' and employed Marxism to understand the economic disparity in industrial Montreal. Early Corsican violent contention, in contrast, included Maoist influences, in particular, through their demand for agrarian reform. The two groups viewed the relationship between their sub-states (Quebec and Corsica) and central states (Canada and France) through a colonial lens, and understood their mobilization against these states and elite minorities (the Anglophone elite in Quebec and the pieds noirs in Corsica) in this light. Both violent movements targeted this colonial relationship. Both the FLQ and FLNC manifestos were economically and politically focused, land and culture were additionally highlighted by the FLNC. This thesis found that sub-state violent contention in the very different contexts of Quebec and Corsica shared an overall pattern, an arc of violent mobilization. The initial mobilization developed from a frustration with moderate political groups; radicalization grew and new tactics were embraced; until turning points that included the assassination of Pierre Laporte by the FLQ and the division of the FLNC into competitive factions, and then a decline of activity, mobilization and recruitment. Although the FLQ and the FLNC contrasted greatly in terms of membership, ideology, organization and strategy, both groups attempted to extend radical space through the use of violent contention in these two very different nations. Ultimately, however, while the FLQ and the FLNC were able to extend or maintain radical space at times, yet they failed to sustain the extension of ideological radical space on the basis on their revolutionary manifestos.

Durch neue, hochflexible Fertigungsverfahren wie das Freiformfräsen eröffnet sich für Kegelradverzahnungen ein großes geometrisches Optimierungspotenzial. Diese Arbeit widmet sich daher der Ermittlung einer optimalen Makro-, Mikro- und Zahnfußgeometrie für bogenverzahnte Kegelräder. Neben dem Zahnprofil und der Zahnfußkurve wird besonderes Augenmerk auf die Ermittlung topologischer Flankenmodifikationen zur Maximierung der Tragfähigkeit gelegt. Gleichzeitig bietet der gezeigte Optimierungsalgorithmus die Möglichkeit zur Minimierung der Geräuschanregung, wodurch der bisher existierende Zielkonflikt zwischen diesen beiden Aspekten aufgehoben werden kann.