V/STOL wind-tunnel testing

Factors influencing effective program planning for V/STOL wind-tunnel testing are discussed. The planning sequence itself, which includes a short checklist of considerations that could enhance the value of the tests, is also described. Each of the considerations, choice of wind tunnel, type of model installation, model development and test operations, is discussed, and examples of appropriate past and current V/STOL test programs are provided. A short survey of the moderate to large subsonic wind tunnels is followed by a review of several model installations, from two-dimensional to large-scale models of complete aircraft configurations. Model sizing, power simulation, and planning are treated, including three areas is test operations: data-acquisition systems, acoustic measurements in wind tunnels, and flow surveying

The Second ICASE/LaRC Industry Roundtable: Session Proceedings

The second ICASE/LaRC Industry Roundtable was held October 7-9, 1996 at the Williamsburg Hospitality House, Williamsburg, Virginia. Like the first roundtable in 1994, this meeting had two objectives: (1) to expose ICASE and LaRC scientists to industrial research agendas; and (2) to acquaint industry with the capabilities and technology available at ICASE, LaRC and academic partners of ICASE. Nineteen sessions were held in three parallel tracks. Of the 170 participants, over one third were affiliated with various industries. Proceedings from the different sessions are summarized in this report

Biophysical and computational studies of biomacromolecular systems

The binding of mono- and dinuclear platinum(II) complexes with both double-stranded and G-quadruplex DNA (QDNA) was explored using a combination of spectroscopic and computational techniques. The stabilising effects on G-quadruplex DNA were assessed and structure-activity relationships developed to guide the future development of QDNA selective complexes. Additionally, two pieces of software were developed, each able to process spectroscopic information. The first application calculates binding constants from various spectroscopic data including circular dichroism and fluorescence. The second program, SOMSpec, uses a machine learning approach to elucidate biomacromolecular structure from circular dichroism and infrared spectra

Mapping Beyond Cartography: the Experimental Maps of Artists Working with Locative Media

The experimental maps produced by artists working with locative media both bear witness to and participate in a radical reworking of the way in which space is conceived and encountered that destabilizes longstanding assumptions about the nature of representation, knowledge, and power. These mapmaking practices, it is argued, operate at the juncture of a cartographic tradition that entails distinctively modern ways of seeing, knowing, and acting in the world, and digital technologies and software operations that propose alternative ways of linking the world up. The thesis charts how these art maps engage in a critique of cartography, the extent to which they remain indebted to it, but also their use of coded operations to pioneer novel apprehensions of space that mark a decisive ‘break’ with a modern worldview. The map works of locative media are accordingly positioned in relation to what is seen as a paradigmatic shift from Cartographic Space to Code Space, and the analysis of case studies supplies a means of comprehending this ongoing transformation, demonstrating that mapping survives beyond cartography but entails a tearing apart of the cartographic surface and the representational epistemology that accompanies it. Gone are the compass, scale and fix-points by which, for centuries, a sense of place was anchored and the world made knowable, yet to be set adrift in this way is not to be left ‘all at sea’. Working with the novel intuitions, forms and geometries that arise from the operations of software code, post-cartographical mapping practices continue to supply a sense of orientation. However, they also pioneer novel forms of territory, and power over territory, that call for new strategies of counter-mapping and, with it, a ‘post-cartographical’ reframing of the study of locative media. Now pictured as a site of contestation between antithetical spatial paradigms, locative media is rehabilitated as a vital force, operating at a pivotal moment, in a broadly epoch-defining reshaping of space and spatial representation

Mass transfer and structural analysis of microfluidic sensors

Thesis (Ph. D.)--Massachusetts Institute of Technology, Biological Engineering Division, February 2006.Includes bibliographical references (leaves 181-191).Surface-based sensors take advantage of the natural high surface-to-volume ratios in microfluidic devices, low reagent consumption and high potential for integration in more complex micro total analysis systems (microTAS or pTAS). This thesis studies the fundamental limits of on-chip integrated microfluidic sensors. More specifically, it focuses on detection methods involving surface interaction in channels with thicknesses on the order of a few microns or less. Through mass transfer analysis, we demonstrate that, for thin enough channels, sample detection is limited by the convective transport of analytes, and neither by diffusion nor reaction. The results provided extend the validity of transport models to include transport in the absence of mass transfer boundary layer. All existing analytic solutions to the Graetz problem are described and compiled. The analysis, complemented by finite element simulations, successfully predicts experimental observations made for on-chip immunoassays in micron-thick fluidic channels. Subsequently, our study of on chip detection systems is carried on with emphasis on resonating cantilever sensors. In order to interpret the output signal from these devices, we develop a dynamic cantilever model to link spatially and temporally dependent mass adsorption with resonance frequency change.(cont.) The mass adsorption is then directly related to the sensors' operating conditions via the mass transfer models previously developed. We then develop a 2D finite-element model capable of predicting the devices response and of extracting bimolecular rate constants. Finally, since hydraulic resistance severely increases as channels get shallower, we provide a structural analysis of polymer-based microsystems. Through scaling and numerical simulations we demonstrate the effect of channel deformation on the flow conditions inside the device and vice versa. Finally, channel deformation is experimentally quantified using optical methods and compared with the models developed. Throughout this thesis, the approach to physical modeling has been to use mathematical and numerical analysis as predictive tools in the design of integrated lab-on-a-chip systems. Whenever possible, scaling and analytic solutions are developed, since they provide a direct relationship between experimental observations, geometry and the multiple dependent variables in the system, and can be readily used as design criteria by the experimentalist.by Thomas Gervais.Ph.D

Streaking and splashing: design of a grazing incidence x-ray streak camera and time-resolved measurements of the structure of water

The performance of cesium iodide photocathodes has been characterized for use with grazing incidence soft x-rays. The total electron yield and pulsed quantum efficiency has been measured in a reflection geometry as a function of photon energy (100 eV to 1 keV), angle of incidence, and the electric field between the anode and photocathode. The total electron yield and pulsed quantum efficiency increase as the x-ray penetration depth approaches the secondary electron escape depth Unit quantum efficiency in a grazing incidence geometry is demonstrated. A weak electnc-field dependence is observed for the total yield measurements, while no significant dependence is found for the pulsed quantum efficiency. The effect of the pulse height distribution on the detective quantum efficiency is discussed Theoretical predictions agree accurately with expenment. Demonstrated unit quantum efficiency in a reflection geometry motivated the development of a grazing incidence x-ray streak camera for the Ultrafast X-ray Science beamline, under construction at the Advanced Light Source, Lawrence Berkeley National Laboratory, USA Design considerations particular to synchrotron radiation sources are discussed. An analytical model and particle simulation for a camera incorporating magnetostatic imaging and meander sweep plates is presented. The camera is characterised with the third harmonic from a titanium-sapphire based laser system, 70 ps intrinsic and 150 fs “sliced” x-ray photon pulses from a synchrotron bend magnet source. A grazing incidence x-ray streak camera with an instrument temporal response of 6 ps is demonstrated. Dynamical changes in the structure factor of liquid water are measured using time-resolved x-ray diffraction techniques with 100 ps resolution. On short time scales, before the system has had time to expand following femtosecond optical excitation, temperatureinduced changes associated with rearrangements of the hydrogen-bonded structure at constant volume are observed. Transient changes in the pair correlation function associated with isochonc heating effects are extracted and interpreted in terms of a decrease in the local tetrahedral ordering in the liquid

Working Papers: Astronomy and Astrophysics Panel Reports

The papers of the panels appointed by the Astronomy and Astrophysics survey Committee are compiled. These papers were advisory to the survey committee and represent the opinions of the members of each panel in the context of their individual charges. The following subject areas are covered: radio astronomy, infrared astronomy, optical/IR from ground, UV-optical from space, interferometry, high energy from space, particle astrophysics, theory and laboratory astrophysics, solar astronomy, planetary astronomy, computing and data processing, policy opportunities, benefits to the nation from astronomy and astrophysics, status of the profession, and science opportunities