The Determination of the Helium Saturation Level of Monomethylhydrazine and MON-3 Nitrogen Tetroxide

No abstract availabl

Mathematical and computer modeling of electro-optic systems using a generic modeling approach

The conventional approach to modelling electro-optic sensor systems is to develop separate models for individual systems or classes of system, depending on the detector technology employed in the sensor and the application. However, this ignores commonality in design and in components of these systems. A generic approach is presented for modelling a variety of sensor systems operating in the infrared waveband that also allows systems to be modelled with different levels of detail and at different stages of the product lifecycle. The provision of different model types (parametric and image-flow descriptions) within the generic framework can allow valuable insights to be gained

Evidence for Two Distinct Morphological Classes of Gamma-Ray Bursts from their Short Timescale Variability

We have analyzed the 241 bursts for which peak counts \C exist in the publicly available Burst and Transient Source Experiment (BATSE) catalog. Introducing peak counts in 1024 ms as a measure of burst brightness \B and the ratio of peak counts in 64 and 1024 ms as a measure of short timescale variability \V, we find a statistically significant correlation between the brightness and the short timescale variability of \g-ray bursts. The bursts which are smoother on short timescales are both faint and bright, while the bursts which are variable on short timescales are faint only, suggesting the existence of two distinct morphological classes of bursts.Comment: 9 pages + 2 Postscript figures available upon request; LATEX v. 2.0

Theoretical Interpretation of the Measurements of the Secondary Eclipses of TrES-1 and HD209458b

We calculate the planet-star flux-density ratios as a function of wavelength from 0.5 microns to 25 microns for the transiting extrasolar giant planets TrES-1 and HD209458b and compare them with the recent Spitzer/IRAC-MIPS secondary eclipse data in the 4.5, 8.0, and 24 micron bands. With only three data points and generic calibration issues, detailed conclusions are difficult, but inferences regarding atmospheric composition, temperature, and global circulation can be made. Our models reproduce the observations reasonably well, but not perfectly, and we speculate on the theoretical consequences of variations around our baseline models. One preliminary conclusion is that we may be seeing in the data indications that the day side of a close-in extrasolar giant planet is brighter in the mid-infrared than its night side, unlike Jupiter and Saturn. This correspondence will be further tested when the data anticipated in other Spitzer bands are acquired, and we make predictions for what those data may show.Comment: 15 pages, including 3 color figures, submitted to the Astrophysical Journa

What is the Value of Home? NOT FOR SALE - West End Interventions

Many Australians today are image consumers. We fail to question the importance of lifestyle imagery created and promoted by Real Estate Agencies whom have no actual part in the physical creation of house, or indeed the intimate making of "home" through our experiences of place. Real Estate Markets dictate how, where, when and what we buy. Re-sale values, profit-making, and value-adding interfere with the crafting of a home over time as a tangible, individual, collaborative, and rich lived experience of dwelling. The "NOT FOR SALE" project is a response and critique of the dominance of real estate forces in West End within the context and unshakable presence of a booming inner-city property market. This proposal originated from an experimental dwelling in Avebury St., West End. This project has been fashioned over a period of several years primarily from recycled local materials, interconnected with the changing needs and spatial requirements of the occupants and project participants. The influence of property markets is of little concern in this home "making". The "NOT FOR SALE" project attempts to question and critique the purely financial value that we as a society place upon our homes. By appropriating and re-coding the Real Estate Signage typologies, we aim to provoke social commentary on the dominance of real estate forces in the West End suburb. There is a strong and rich tradition of anti-consumerist activist graffiti in West End. Activists re-code signs and property with political commentary and critique. The "NOT FOR SALE" project draws upon this tradition through our RRESign (Recodified Real Estate Signs): we aim to redress the dominant commercial forces associated with the single house/property. Collectively, at the scale of the street, these RRESigns will reflect a critique of street scale, amenity, and character. Finally, at the scale of the suburb, the network of RRESigns will reflect a critique of the idea of place making. Collectively, the aim of the "NOT FOR SALE" RRESign interventions is to highlight the idea of making and the material characteristics of dwelling that challenges the cultural value of commodified property, re-defining and prioritising the idea of "home". Conventional Real Estate signs use images and text to sell an idea of home: our proposed interventions sell nothing, and are rather celebrations of the joy of making tactile, handcrafted objects, and by extension, the making and crafting of home. The intimate and experiential understanding of home will be harnessed through the engagement of local residents. Community groups within West End such as Local Push can further disseminate the RRESign interventions. The signs will be constructed West End-specific materials (old signs purchased from inexpensive second-hand material merchant Reverse Garbage in Montague Rd.): turning post-consumer waste into objects of material beauty and social critique. Residents and community groups will be encouraged to place their RRESigns outside their properties and adjacent real estate signs, frustrating and recoding the existing For-Sale signs that currently dominate the West End street scape. The project is dependent on the support of the local residents, extending from a few signs in Avebury St. to a network of RRESigns throughout West End. A commentary on people's responses to the project will be linked to the www.apbv.com.au website. What is the value of home

Coupled quantum wires

We study a set of crossed 1D systems, which are coupled with each other via tunnelling at the crossings. We begin with the simplest case with no electron-electron interactions and find that besides the expected level splitting, bound states can emerge. Next, we include an external potential and electron-electron interactions, which are treated within the Hartree approximation. Then, we write down a formal general solution to the problem, giving additional details for the case of a symmetric external potential. Concentrating on the case of a single crossing, we were able to explain recent experinents on crossed metallic and semiconducting nanotubes [J. W. Janssen, S. G. Lemay, L. P. Kouwenhoven, and C. Dekker, Phys. Rev. B 65, 115423 (2002)], which showed the presence of localized states in the region of crossing.Comment: 11 pages, 10 figure

Simultaneous Observations of GRS 1758-258 in 1997 by VLA, IRAM, SEST, RXTE and OSSE: Spectroscopy and Timing

We report the results of our multi-wavelength observations of GRS 1758-258 made in August 1997. The energy bands include radio, millimeter, X-ray, and gamma-ray. The observations enable us to obtain a complete spectrum of the source over an energy range of 2 - 500 keV. The spectrum shows that GRS 1758-258 was in its hard state. It is well fitted by the Sunyaev-Titarchuk (ST) Compton scattering model. The spectrum is also fit by a power law with an exponential cutoff (PLE) plus a soft black-body component. The temperature of the soft component is about 1.2 keV, and the energy flux is less than 1.5% of the total X- and gamma-ray flux. The deduced hydrogen column density is in the range of (0.93 - 2.0) 10^{22} cm^{-2}. No significant iron lines are detected. The radio emission has a flat energy spectrum. The daily radio, X-ray and gamma-ray light curves show that GRS 1758-258 was stable during the observation period, but was highly variable on smaller time scales in X- and gamma-rays. The power density spectra are typical for the low-state, but we find the photon flux for the 5 to 10 keV band to be more variable than that in the other two energy bands (2 - 5 keV and 10 - 40 keV). Harmonically spaced quasi-periodic oscillations (QPOs) are observed in the power spectra. The phase lags between the hard photons and the soft photons have a flat distribution over a wide range of frequencies. A high coherence of about 1.0 (0.01 - 1 Hz) between the hard photons and the soft photons is also obtained in our observations. We compare these results with two variation models. Our millimeter observations did not reveal any conclusive signatures of an interaction between the jet from GRS 1758-258 and the molecular cloud that lies in the direction of GRS 1758-258.Comment: 32 pages, 13 figures, to appear in ApJ, 2000, V.533, no. 1, Apr. 10. For better figure resolution, please directly download the paper from http://spacsun.rice.edu/~lin/publication.htm