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This dissertation uses a case study of 2600: The Hacker Quarterly to consider how the practices of a hacker public might be theorized as a rhetorical activity. The project is contextualized within a history of hacking (building from a narrative that centers on Levy's 1984 book Hackers) and within the arc of recent copyright legislation, specifically the Digital Millennium Copyright Act (DMCA) and the 2011-12 Stop Online Piracy Act (SOPA) debates. Within this framework, the dissertation examines how specific patterns and cases within 2600 might further our understanding of the rhetorical canons of memory and delivery and of dissent in digital spaces. Specifically, the project presents three practices of memory at work in 2600: Aggregating, Fingerprinting, and Narrating. Drawing on the work of Collin Gifford Brooke and Mary Carruthers, among others, the dissertation examines how texts printed in 2600 present memory not as an inert technology but rather as a practice and a pedagogy—a response to the increasing commercialization of technology. The dissertation then uses Jim Porter's techne of digital delivery to analyze three specific moments in 2600's history (the 1985 U.S. Government raid on New Jersey hackers, the E911 lawsuit, and the DeCSS narrative), illustrating how our spaces of textual production have become increasingly regulated and commercialized and considering how that regulation/commercialization affects our understanding of ownership, circulation, and the public sphere. Building on Michel de Cereteau's concept of strategies and tactics and Michael Warner's theory of (counter)publics, the dissertation ultimately argues that a history of hacker publics offers one way to reconceptualize and reintegrate theories and technologies of digital circulation into our scholarly work and curricular goals. / Ph. D.

This thesis presents the results of two 2-D computational studies of a circulation control Inlet Guide Vane (IGV) that takes advantage of the Coanda effect for flow vectoring. The IGV in this thesis is an uncambered airfoil that alters circulation around itself by means of a Coanda jet that exhausts along the IGV's trailing edge surface. The IGV is designed for an axial inlet flow at a Mach number of 0.54 and an exit flow angle of 11 degrees. These conditions were selected to match the operating conditions of the 90% span section of the IGV of the TESCOM compressor rig at the Compressor Aero Research Laboratory (CARL) located at Wright-Patterson AFB. Furthermore, using the nominal chord (length from leading edge of the IGV to the jet exit) for the length scale, the Reynolds number for the circulation control IGV in this region was 5e⁵. The first study was a code and turbulence model comparison, while the second study was an optimization study which determined optimal results for parameters that affected circulation around the IGV. Individual abstracts for the two studies are provided below. To determine the effect of different turbulence models on the prediction of turning angles from the circulation control IGV, the commercial code GASP was employed using three turbulence models. Furthermore, to show that the results from the optimization study were code independent a code comparison was completed between ADPAC and GASP using the Spalart-Allmaras turbulence model. Turbulence models employed by GASP included: two isotropic turbulence models, the one equation Spalart-Allmaras and the two-equation Wilcox 1998 k-ω. The isotropic models were then compared to the non-isotropic stress transport model Wilcox 1998 Stress-ω. The results show good comparison between turning angle trends and pressure loss trends for a range of blowing rates studied at a constant trailing edge radius size. When the three turbulence models are compared for a range of trailing edge radii, the models were in good agreement when the trailing edge is sufficiently large. However, at the smallest radius, isotropic models predict the greatest amount of circulation around the IGV that may be caused by the prediction of transonic flow above the Coanda surface. The optimization study employed the CFD code ADPAC in conjunction with the Spalart-Allmaras turbulence model to determine the optimal jet height, trailing edge radius, and supply pressure that would meet the design criteria of the TESCOM (TESt COMpressor) rig while minimizing the mass flow rate and pressure losses. The optimal geometry that was able to meet the design requirements had a jet height of h/C_n = 0.0057 and a trailing edge Radius R/C_n = 0.16. This geometry needed a jet to inflow total pressure ratio of 1.8 to meet the exit turning angle requirement. At this supply pressure ratio the mass flow rate required by the flow control system was 0.71 percent of the total mass flow rate through the engine. The optimal circulation control IGV had slightly lower pressure losses when compared to the cambered IGV in the TESCOM rig. / Master of Science

Perception of movement within and between designed spaces starts with the uniquely human ability to relate ourselves to our surroundings, followed by a relationship to the sequential experience of our movement throughout. Architecture is simply a building without the life and movement of the people who use the design, yet individuals may experience and relate to the same design differently. Habitual routes and repetitive paths of movement dull our experience of these spaces while moving towards or within a new space can allow our perception to expand as we take in a new environment, creating excitement but also tension within us. At our center, there is a phenomenological connection between a preceding space and personal orientation with a future space, helping us understand the new space in relation to ourselves, no matter the mode of transportation for arrival. Transportation hubs are intersections of time, connecting people in motion and guiding both habitual and unfamiliar subjects along their continuous journey. Studying the movement within the Washington metropolitan area, the New Carrollton Station in Maryland perforates the Capital Beltway as a gateway to the region. This thesis aims to understand how people interact with path-connected spaces and connect each subject's mode of arrival, goal, and choice of movement between a newly designed station. / Master of Architecture / With the uniquely human ability to relate ourselves to our surroundings, the way we experience moving through architectural and urban designs is impacted by the way we perceive the changing surrounding space. Architecture is simply a building without the life and movement of the people who use the building, yet individuals may experience and relate to the same building differently. Habitual routes, such as commutes that we do daily, may dull our experience of these spaces, while moving towards or being within a new building can open our senses and perception, taking in the new environment and creating excitement but also anxiety within us. At a psychological and phenomenological level, we can mentally connect the space where we just were with the new space we are in; our sense of direction works with our personal orientation of front and back, left and right. This is still the case if we arrive at a new place by bus or train: our orientation is in relation to the direction we are facing and what is in front of us when we get off. Transportation hubs/stations are designed to connect people in motion, guiding both habitual and unfamiliar riders along their continuous journey to a new place or mode of transportation. Studying the urban movement within the Washington metropolitan area, the New Carrollton Station in Maryland is located along the edge of the region, the Capital Beltway, and welcomes people to the region. This thesis aims to understand how people interact with architecture as they move throughout their daily lives and connect people as they move throughout a newly designed station.

Reproduction de : Thèse d'exercice : Médecine : Nancy 1 : 2006. / Titre provenant de l'écran-titre.

Satellite data have shown that east-west oriented cloud bands, known as Intertropical convergence zone (ITCZ), propagate eastwards along the equator throughout the year and northwards during boreal summer on intraseasonal time scales. The northward propagations over Bay of Bengal have important connection with onset of south Asian monsoon and active-break cycles of the Indian monsoon. Some studies on mean structure of ITCZ have concluded that preferred location of ITCZ is governed by meridional variation of sea surface temperature (SST) while other studies have stressed the importance of heating in the free atmosphere. Studies on the migration of ITCZ have shown that northward migration of maximum convergence zone is due to generation of positive barotropic vorticity north of the convection in the boundary layer due to internal dynamics of the atmosphere. In the present study mean and transient structure of northward migration of ITCZ over Bay of Bengal is simulated with the help of a general circulation model (GCM). The mean ITCZ is found not to occur at SST maximum or SST gradient maxima. A new simple model for the mean state of ITCZ based on moisture budget, linear friction and hydrostatic assumption is proposed. It highlights the relative importance of SST and atmospheric effects in generation of maximum convergence. The large cancellation between the effect of SST on boundary layer and thermodynamic effects in free troposphere is shown to control convergence. The model also shows that latitude and time independent linear friction parameterization in a simple model is able to predict monthly mean location of ITCZ in a GCM. The results give a quantitative understanding about the relative role of surface effects and atmospheric effects in determining location of the mean ITCZ. A simple linear model for understanding the mechanism of instability that governs the northward migration of ITCZ is proposed. Vertical shear in mean winds couples the barotrpic and baroclinic modes in free troposphere in this model. The model is able to predict the correct scale with standard values of friction and diffusion parameters. The mechanism of instability is found to be due to internal dynamics of troposphere. It is shown that direction of propagation is decided by vertical shear in zonal as well as meridional mean winds. This is contrary to the previous studies which conclude that either vertical shear in zonal winds or vertical shear in meridional winds control the direction of propagation.

The middle atmosphere transport is mostly controlled by a large-scale meridional circulation, namely the Brewer-Dobson circulation. In this thesis, climatology and variability of the Brewer-Dobson circulation and the middle atmosphere has been analysed using the Canadian Middle Atmosphere Model (CMAM30-Ext). A number of key variables are used including the age of air, residual velocities, residual stream function, temperature and zonal wind. The analysis of the climatology of the age of air shows, in particular, that young air gets generated near the tropical tropopause, which then travels poleward. The residual stream function shows that the Brewer-Dobson circulation dominates the winter hemispheres around the solstices and becomes nearly symmetrical, with respect to the equator, around the equinoxes. The empirical orthogonal function analysis is applied to explore the modes of variability in the middle atmosphere. The analysis identifies, in particular, the semi-annual oscillation, the quasi-biennial oscillation with moderate explained variance compared to the variance explained by the annual cycle. In addition, the analysis also reveals the emergence of the solar cycle. Powered by TCPDF (www.tcpdf.org)

Experiments have been conducted with a two-dimensional timedependent, numerical model of the general circulation of the atmosphere up to the mesopause. A scheme for the calculation of cooling rates due to the 15(mu)m band of carbon dioxide is developed. It uses the Curtis matrix approach which incorporates cooling-to-space, transfer of radiation between atmospheric layers and non-equilibrium effects in the upper mesosphere. The sensitivity of the cooling rate calculations to the choice of collisional relaxation time is investigated. An 'almost exact' scheme to calculate heating rates due to the absorption of solar radiation by ozone and molecular oxygen is presented. Use of both new radiation schemes enables the diabatic heating rate to be calculated to the upper boundary of the model. Other heat sources in the region of the mesopause are discussed. Incorporation of the new schemes considerably improves the modelled temperature structure of:the stratosphere and lower mesosphere. The upper mesosphere is not well reproduced with no indication of the observed cold summer mesopause. The heat and momentum budgets of the mesosphere are studied. Eddy momentum fluxes derived from satellite observations of planetary waves are found to be significant for the circulation and transport properties of the stratosphere but incapable of producing the required distribution of angular momentum in the mesosphere. A Rayleigh friction parameterisation is included in the mesosphere to reproduce the observed zonal wind and temperature structure. Momentum deposition by tides and gravity waves is discussed. Curtis matrices are calculated with higher mixing ratios of carbon dioxide and the effects of increased atmospheric CO2 on stratospheric temperatures and ozone is investigated. Temperature decreases of up to about 10K are predicted with increases in ozone concentration in the upper stratosphere. In the lower stratosphere the ozone increases are restricted to high latitudes and a decrease shown in equatorial regions. The latitudinal variations are reflected in the ozone column density. An experiment is conducted in which chlorofluorocarbons are released into the model atmosphere and the effects on stratospheric ozone are in exactly the opposite sense to those predicted for the CO2 case. A run in which CO2 and CFCs are introduced simultaneously shows that the two effects are not linearly additive. A simple photochemical theory is used to investigate the temperature dependence of ozone and to explain the non-linearity of the coupled experiment.

Oxy-Pherol-ET (OP-ET) is an artificial blood substitute composed of perfluoro~ributylamine (FC-43) emulsified with pluronic (FC-68) and hydroxyethyl starch as a plasma expander. This blood substitute is quite unique in that it has a high oxygen and carbon dioxide carrying capacity and is inert. In order for OP-ET to work, it must co-exist in circulation with blood components. This research project has been an investigation of the effect of OP-ET on the circulation regulatory agents (hormonal, etc). The aorta and vena cava were examined to assess the influence of OPET on the structural components of circulation. Since the kidney plays an important role in the overall regulation of circulation, the influence of the OP-ET on its function and structure were examined also. Stimulation of the renin-angiotensin system by hemorrhage, low sodium diet (LSD), and reduced renal perfusion pressure resulted in an increased release of renin in animals treated with OP-ET. Animals previously exchange-transfused with OP-ET were subsequently monitored daily for changes in weight, water intake, and urinary salt and water output. In OP-ET treated animals weight increase was when slow compared to control animals. The water intake of the animals exchange-transfused animals was substantially greater than control animals for the same time period. Animals prepared with indwelling catheters and exchange-transfused with OP-ET were monitored for their ability to respond to pharmacological concentrations of catecholamines and angiotensin II. Under these conditions animals showed no significant difference in blood pressure response when compared to control animals that were exchange-transfused with donor animals' RBCs and treated similarly with angiotensin and catecholamines. Previously transfused animals were monitored to determine the effect of OP-ET on the kidney. Under these conditions there was a diuretic-induced immediate increase in urinary sodium excretion and a gradual increase in urinary potassium. These were expected responses for this diuretic agent. Scanning electron microscopy (SEM) of exchange-transfused animals did not reveal observable differences within the endothelium of the aorta. The vena caval endothelium of the exchange-transfused animals showed no significant changes. There were no observable alterations in the glomerular capillaries by 7 days post-transfusion. The data warrant the conclusion that mechanisms which normally regulate the circulation still function in the presence of the blood substitutes used in this study. The use of OP-ET has great potential in emergency medicine and remote areas of the world where whole blood would be difficult to maintain.

In the pulmonary circulation, alveolar hypoxia contributes to blood flow regulation. Hypoxic pulmonary vasoconstriction (HPV) involves both pulmonary arteries and veins, but little is known of the contractile mechanisms specific to the veins. The aim of these studies was to examine the hypoxic response in small porcine intrapulmonary veins in relation to the arterial response, and investigate the effects of hypoxia on ion conductances in single myocytes from intrapulmonary veins. In wire myography experiments, intrapulmonary veins contracted more than sizematched arteries in response to hypoxia and agonists KCl and PGF2α. Venous contractions were inhibited by removal of extracellular Ca2+ or in the presence of Clchannel blocker NFA, effects not seen in the arteries. To examine the mechanisms of venous contraction at cellular level, single pulmonary vein smooth muscle cells (PVSMC) were freshly isolated and characterised morphologically and electrophysiologically for the first time. In patch-clamp studies, hypoxia reversibly inhibited a whole-cell outward current in the presence of BKCa channel antagonist Penitrem A. By subtracting currents recorded in normoxia and hypoxia, a novel hypoxia-sensitive K+ current (IK(H)) was revealed in PVSMC. IK(H) was a rapidly activating, partially inactivating current and was sensitive to KV channel blocker 4-AP. The biophysical properties of IK(H) revealed the voltage window of current availability with a peak near the resting membrane potential of PVSMC. In conclusion, these findings highlight differences between the contractile properties of veins and arteries and reveal a significant contribution of Ca2+ influx and an NFA-sensitive conductance during venous contraction to agonists and hypoxia. Furthermore, the results suggest that a novel hypoxia-sensitive KV current contributes to membrane potential under resting conditions in PVSMC and its inhibition by hypoxia may contribute to the initiation of HPV in porcine intrapulmonary veins.