Analysis of hypersonic pressure and heat transfer tests on a flat plate with a flap and a delta wing with body, elevons, fins, and rudders Final report

Hypersonic boundary layer separation and flow field interference analysis during Dyna-Soar space glider testin

Surge motion of an ice floe in waves: comparison of theoretical and experimental models

A theoretical model and an experimental model of surge motions of an ice floe due to regular waves are presented. The theoretical model is a modified version of Morrison's equation, valid for small floating bodies. The experimental model is implemented in a wave basin at scale 1:100, using a thin plastic disk to model the floe. The processed experimental data displays a regime change in surge amplitude when the incident wavelength is approximately twice the floe diameter. It is shown that the theoretical model is accurate in the large wavelength regime, but highly inaccurate for the small wavelength regime.Comment: 11 pages, 10 figure

Graduate Recital: Thomas Giles

Kemp Recital HallApril 15, 2012Sunday Evening6:30 p.m

Antipodean American literary studies : An interview with Paul Giles [Interview]

Paul Giles is Challis Professor of English at the University of Sydney, Australia. He is the author of many books discussing English, American, and Australian literature from transnational perspectives, including American Catholic Arts and Fictions: Culture, Ideology, Aesthetics (Cambridge University Press, 1992), Virtual Americas: Transnational Fictions and the Transatlantic Imaginary (Duke University Press, 2002), The Global Remapping of American Literature (Princeton University Press, 2011), Antipodean America: Australasia and the Constitution of U.S. Literature (Oxford University Press, 2013). He was previously President of the International American Studies Association (2005-2007) and Director of the Rothermere American Institute at Oxford University (2003-2008). He is currently serving as president of the International Association of University Professors of English and completing a trilogy of books on cultural representations of antipodean time, of which the first two volumes have recently been published: Backgazing: Reverse Time in Modernist Culture (Oxford University Press, 2019) and The Planetary Clock: Antipodean Time and Spherical Postmodern Fictions (Oxford University Press, 2021)

Docking control of an autonomous underwater vehicle using reinforcement learning

To achieve persistent systems in the future, autonomous underwater vehicles (AUVs) will need to autonomously dock onto a charging station. Here, reinforcement learning strategies were applied for the first time to control the docking of an AUV onto a fixed platform in a simulation environment. Two reinforcement learning schemes were investigated: one with continuous state and action spaces, deep deterministic policy gradient (DDPG), and one with continuous state but discrete action spaces, deep Q network (DQN). For DQN, the discrete actions were selected as step changes in the control input signals. The performance of the reinforcement learning strategies was compared with classical and optimal control techniques. The control actions selected by DDPG suffer from chattering effects due to a hyperbolic tangent layer in the actor. Conversely, DQN presents the best compromise between short docking time and low control effort, whilst meeting the docking requirements. Whereas the reinforcement learning algorithms present a very high computational cost at training time, they are five orders of magnitude faster than optimal control at deployment time, thus enabling an on-line implementation. Therefore, reinforcement learning achieves a performance similar to optimal control at a much lower computational cost at deployment, whilst also presenting a more general framework

The dynamism of salt crust patterns on playas

Playas are common in arid environments and can be major sources of mineral dust that can influence global climate. These landforms typically form crusts that limit evaporation and dust emission, modify surface erosivity and erodibility, and can lead to over prediction or under prediction of (1) dust-emission potential and (2) water and heat fluxes in energy balance modeling. Through terrestrial laser scanning measurements of part of the Makgadikgadi Pans of Botswana (a Southern Hemisphere playa that emits significant amounts of dust), we show that over weeks, months, and a year, the shapes of these surfaces change considerably (ridge thrusting of >30 mm/week) and can switch among continuous, ridged, and degraded patterns. Ridged pattern development changes the measured aerodynamic roughness of the surface (as much as 3 mm/week). The dynamic nature of these crusted surfaces must be accounted for in dust entrainment and moisture balance formulae to improve regional and global climate models

Concert recording 2015-03-05

[Track 01]. Three contrapuncti from The art of fugue BWV 1080. Contrapunctus I ; [Track 02]. Contrapunctus IV ; [Track 03]. Contrapunctus IX / Johann Sebastian Bach -- [Track 04]. Premier quatuor op. 53. Adagio-allegro ; [Track 05]. Adagio sostenuto ; [Track 06]. Allegro vivace ; [Track 07]. Allegretto / Jean Baptiste Singelee -- [Track 08]. Saxophone quartet. Molto moderato ; [Track 09]. Andantio giovale ; [Track 10]. Adagio-allegro molto ; [Track 11]. Recitatives ; Presto meccanico / Stephen Dankner