Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (p. 130-136).

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (p. 219-228).

The application of the dynamical baffles in the mechanical systems, when the sources of stimulation are impossible to abolish, is one of the ways to fight against the harmful vibrations. The model of a dynamic baffle was applied for suppression of oscillations of the nonlinear mechanical systems. With the help of the baffle the system parameters were determined with the smallest possible amplitudes.

Underwater (phreatic) caves are a ubiquitous landform on coastal karst terrain, but the marine geological processes operating in these systems are largely unknown. This dissertation redresses the problem by asking if Bermudian phreatic cave sediments archive sea-level and climate information? An important premise is that coastal cave environments are not identical. They can be categorized based on whether they are terrestrially-influenced (anchialine), completely flooded by saline groundwater (submarine), positioned at sea level (littoral) or in the vadose zone (vadose). For the first time the boundary between modern anchialine and submarine cave environments has been distinguished in Green Bay Cave using a multi-proxy approach (benthic foraminifera, sedimentary organic matter content and carbon isotopic composition - ?13Corg, and grain-size analysis). Twelve push cores were extracted from Green Bay Cave and dated with twenty 14C dates, recovering the first underwater cave succession spanning the Holocene (13 ka to present). Green Bay Cave transitioned through all major cave environments during Holocene sea-level rise (vadose, littoral, anchialine, and submarine), providing a sedimentary model for global cave successions. These relationships provide a novel means to solve Quaternary sea-level and climate problems. For sea level, two examples indicate that the littoral cave can be used as a sea-level indicator, distinguished stratigraphically by microfossil or sedimentary proxies. First, the elevation and timing of when Green Bay Cave was a littoral environment indicates Bermuda experienced an abrupt ~6.4 m sea-level rise at 7.7 ka, coinciding with final collapse of the Labrador sector of the Laurentide Ice Sheet. Second, microfossils preserved in elevated caves at +21 m above modern sea level and dated to marine isotope stage 11 (U-series, amino acid racemization) are consistent with modern Bermudian caves and co-stratigraphic sea level. For climate problems, annual temperature monitoring in Walsingham Cave indicates that cave water is thermally comparable to regional oceanographic conditions in the Sargasso Sea. Three sediment cores dated with sixteen radiocarbon dates indicate that Bermuda’s coldest and stormiest conditions of the last 3.2 ka occurred during the Little Ice Age (proxies: ?18Oc, grain size, bulk organic matter).

The first two empirical orthogonal functions of the winter (DJF) surface air temperature (SAT) over North America are associated with the North Atlantic Oscillation (NAO) and the Pacific/North American (PNA) pattern in the NCEP reanalysis. Lagged correlations between the North American SAT structures and the sea surface temperature (SST) were computed. There is a small lag between the tri-pole SST anomaly pattern of the North Atlantic Ocean and the first SAT mode. The second SAT mode lags the eastern Tropical Pacific SST anomaly by two months, associated with ENSO through the winter. A similar analysis is conducted on the seasonal forecasts to see if the forecast models capture the above links. GCM3 captures the ENSO forcing and has the PNA response. GEM captures the link between the SAT and the tripole SST anomaly pattern in North Atlantic. Although GEM captures the ENSO signal, it cannot form the PNA to further this tropical forcing into North America.

Mechanical ventilation saves lives, but it is an intervention fraught with the potential for serious complications. Prevention of these complications has become the focus of research and critical care in the last twenty years. This thesis presents the first use, or the application under new conditions, of three technologies that could contribute to optimization of mechanical ventilation. Optoelectronic plethysmography was used in Papers I and II for continuous assessment of changes in chest wall volume, configuration, and motion in the perioperative period. A forced oscillation technique (FOT) was used in Paper III to evaluate a novel positive end-expiratory pressure (PEEP) optimization strategy. Finally, in Paper IV, FOT in conjunction with an optical sensor based on a self-mixing laser interferometer (LIR) was used to study the oscillatory mechanics of the respiratory system and to measure the chest wall displacement. In Paper I, propofol anesthesia decreased end-expiratory chest wall volume (VeeCW) during induction, with a more pronounced effect on the abdominal compartment than on the rib cage. The main novel findings were an increased relative contribution of the rib cage to ventilation after induction of anesthesia, and the fact that the rib cage initiates post-apneic ventilation. In Paper II, a combination of recruitment maneuvers, PEEP, and reduced fraction of inspired oxygen, was found to preserve lung volume during and after anesthesia. Furthermore, the decrease in VeeCW during emergence from anesthesia, associated with activation of the expiratory muscles, suggested that active expiration may contribute to decreased functional residual capacity, during emergence from anesthesia. In the lavage model of lung injury studied in Paper III, a PEEP optimization strategy based on maximizing oscillatory reactance measured by FOT resulted in improved lung mechanics, increased oxygenation, and reduced histopathologic evidence of ventilator-induced lung injury. Paper IV showed that it is possible to apply both FOT and LIR simultaneously in various conditions ranging from awake quiet breathing to general anesthesia with controlled mechanical ventilation. In the case of LIR, an impedance map representing different regions of the chest wall showed reproducible changes during the different stages that suggested a high sensitivity of the LIR-based measurements.

It is astonishing both how little and how much we know about neutrinos. On one hand, the neutrino is the second most abundant particle in our Universe. Neutrinos may be created in the Sun, core collapse supernovae, cosmic rays, geological background radiation, supernova remnants and in the Big Bang. On the other hand, they have unimaginably small masses and are unwilling to react with their surroundings. Because of their abundance and their inclination to show us physics beyond the standard model of particle physics, neutrinos are hoped to carry yet unknown information of the Universe. However, it will take some effort and time to persuade the neutrinos to tell us what they know. Among the things we do not yet know of the neutrinos, is the -phase in the neutrino mixing matrix. If is in fact non-zero, neutrino flavour oscillations violate CP-symmetry. Also, if neutrino masses are introduced in the standard model through the See-Saw mechanism and if leptogenesis is a valid theory, CP-violation in neutrino oscillations could help explain why our Universe has no antimatter even though equal amounts of matter and antimatter should have been created at the Big Bang. In this thesis, we investigate the flavour evolution of supernova neutrinos. We present the full Hamiltonian in the flavour basis for our system and identify how the different contributions affect the evolution and in which environment. We also present a theoretical motivation from [1, 2] as to how a non-zero -phase affects the flavour evolution and the final energy spectra. The analytical conclusion is that it has no impact under the assumptions made in our analysis. Thus, the -phase may not be measurable from supernova neutrinos.

Parkinson’s disease (PD) is accompanied by a significant amount of beta β-band (11Hz-30Hz) neuronal and local field potential (LFP) oscillatory activity in the subthalamic nucleus (STN). The aim of this study was to measure the spatial extent of β coherent activity in the STN and coherence between STN-SNr in PD patients OFF levodopa by systematically varying the vertical distance between two microelectrodes. We found significant β-LFP coherence across the dorsoventral extent of STN. Spatially extended beta LFP was positively correlated with the mUPDRS scores of the PD patients in the OFF state. Additionally, a significant coherence was found between β-LFPs in dorsal STN and dorsal SNr. These data suggest that the whole STN may be entrained within the β band in PD patients OFF meds. The finding of coherence between STN and SNr suggests that β oscillations synchronize both the input and output nuclei of the basal ganglia.

Parkinson’s disease (PD) is accompanied by a significant amount of beta β-band (11Hz-30Hz) neuronal and local field potential (LFP) oscillatory activity in the subthalamic nucleus (STN). The aim of this study was to measure the spatial extent of β coherent activity in the STN and coherence between STN-SNr in PD patients OFF levodopa by systematically varying the vertical distance between two microelectrodes. We found significant β-LFP coherence across the dorsoventral extent of STN. Spatially extended beta LFP was positively correlated with the mUPDRS scores of the PD patients in the OFF state. Additionally, a significant coherence was found between β-LFPs in dorsal STN and dorsal SNr. These data suggest that the whole STN may be entrained within the β band in PD patients OFF meds. The finding of coherence between STN and SNr suggests that β oscillations synchronize both the input and output nuclei of the basal ganglia.

The subject of this experimental investigation is to measure the dynamic stability derivatives in roll plane for an oscillating combat aircraft model by using forced oscillation technique. In forced oscillation technique the model is forced to oscillate around the center of gravity according to a harmonic motion of small amplitude and low frequency. The aerodynamic reactions are measured by an internal balance placed inside the model. The thesis presents a brief description of the test rig and the measurement system. The theory of dynamic stability derivatives and forced oscillation technique are also explained. The data is collected and analyzed by using a data acquisition system written with under the Labview programming language. Systematic analysis of the static and dynamic tests results and effect of various parameters (angle of attack, sideslip angle, oscillation frequency and amplitude, wind velocity) on these results are presented. Comparison of the present results with previous results obtained in other test facilities is also given. Design and manufacture process of a new angle of attack mechanism is also given in this thesis.