Introductory comments

Vibroacoustic and thermal environment data gathered from the first three flights of the space shuttle are presented. The characterization of the particulate, gaseous, and electromagnetic emissions associated with the shuttle flight is emphasized. Measurements of vehicle glow light emissions and material effects (mass loss) due to the low Earth environment interactions with the shuttle vehicle are presented

Shuttle on-orbit contamination and environmental effects

Ensuring the compatibility of the space shuttle system with payloads and payload measurements is discussed. An extensive set of quantitative requirements and goals was developed and implemented by the space shuttle program management. The performance of the Shuttle system as measured by these requirements and goals was assessed partly through the use of the induced environment contamination monitor on Shuttle flights 2, 3, and 4. Contamination levels are low and generally within the requirements and goals established. Additional data from near-term payloads and already planned contamination measurements will complete the environment definition and allow for the development of contamination avoidance procedures as necessary for any payload

Contamination of spacecraft by recontact of dumped liquids

Liquids partially freeze when dumped from spacecraft producing particles which are released into free space at various velocities. Recontact of these particles with the spacecraft is possible for specific particle sizes and velocities and, therefore, can become contamination for experiments within the spacecraft or released experiments as a result of waste and potable water dumped from Space Shuttle. An examination of dump characteristics was conducted on STS-29 using both on-board video records and ground based measurements. A preliminary analysis of data from this flight indicates particle velocities are in the range of 30 to 75 ft/sec and recontact is possible for limited particle sizes

Alien Registration- Leger, Mary C E. (Auburn, Androscoggin County)

https://digitalmaine.com/alien_docs/31157/thumbnail.jp

Spectral signatures of photosynthesis II: coevolution with other stars and the atmosphere on extrasolar worlds

As photosynthesis on Earth produces the primary signatures of life that can be detected astronomically at the global scale, a strong focus of the search for extrasolar life will be photosynthesis, particularly photosynthesis that has evolved with a different parent star. We take planetary atmospheric compositions simulated by Segura, et al. (2003, 2005) for Earth-like planets around observed F2V and K2V stars, modeled M1V and M5V stars, and around the active M4.5V star AD Leo; our scenarios use Earth's atmospheric composition as well as very low O2 content in case anoxygenic photosynthesis dominates. We calculate the incident spectral photon flux densities at the surface of the planet and under water. We identify bands of available photosynthetically relevant radiation and find that photosynthetic pigments on planets around F2V stars may peak in absorbance in the blue, K2V in the red-orange, and M stars in the NIR, in bands at 0.93-1.1 microns, 1.1-1.4 microns, 1.5-1.8 microns, and 1.8-2.5 microns. In addition, we calculate wavelength restrictions for underwater organisms and depths of water at which they would be protected from UV flares in the early life of M stars. We estimate the potential productivity for both surface and underwater photosynthesis, for both oxygenic and anoxygenic photosynthesis, and for hypothetical photosynthesis in which longer wavelength, multi-photosystem series are used.Comment: 59 pages, 4 figures, 4 tables, forthcoming in Astrobiology ~March 200

On chopper effects in discrete-time ΣΔ modulators

Analog-to-digital converters based on ΣΔ modulators are used in a wide variety of applications. Due to their inherent monotonous behavior, high linearity, and large dynamic range, they are often the preferred option for sensor and instrumentation. Offset and flicker noise are usual concerns for this type of applications, and one way to minimize their effects is to use a chopper in the front-end integrator of the modulator. Due to its simple operation principle, the action of the chopper in the integrator is often overlooked. In this paper, we provide an analytical study of the static effects in ΣΔ modulators, which shows that the introduction of chopper is not transparent to the modulator operation and should thus be designed with care.This work has been partially funded by the Spanish Government project TEC-2007-68072 and the CSIC project 200850I213.Peer reviewe

A Committee to Manage Innovative Learning Spaces: Balancing Committee Size, Cross-Campus Representation, and Decision-Making Power

The growth in active learning classrooms represents a major shift in the pedagogy and built environment of higher education. While a robust literature exists to discuss the development, use, and evaluation of these innovative learning spaces, the practical considerations of managing innovative learning spaces has not received the same level of attention. This article describes the management model at _____ University, outlining key workflow considerations: committee size, cross-campus representation, and decision-making power. The conclusion sets out future research opportunities related to the institutional dynamics of innovative learning space management

Infrared Spectroscopy of the Diffuse Ionized Halo of NGC 891

We present infrared spectroscopy from the Spitzer Space Telescope at one disk position and two positions at a height of 1 kpc from the disk in the edge-on spiral NGC 891, with the primary goal of studying halo ionization. Our main result is that the [Ne III]/[Ne II] ratio, which provides a measure of the hardness of the ionizing spectrum free from the major problems plaguing optical line ratios, is enhanced in the extraplanar pointings relative to the disk pointing. Using a 2D Monte Carlo-based photo-ionization code which accounts for the effects of radiation field hardening, we find that this trend cannot be reproduced by any plausible photo-ionization model, and that a secondary source of ionization must therefore operate in gaseous halos. We also present the first spectroscopic detections of extraplanar PAH features in an external normal galaxy. If they are in an exponential layer, very rough emission scale-heights of 330-530 pc are implied for the various features. Extinction may be non-negligible in the midplane and reduce these scale-heights significantly. There is little significant variation in the relative emission from the various features between disk and extraplanar environment. Only the 17.4 micron feature is significantly enhanced in the extraplanar gas compared to the other features, possibly indicating a preference for larger PAHs in the halo.Comment: 35 pages in ApJ preprint format, 8 figures, accepted for publication in ApJ. Minor change to Introduction to give appropriate credit to earlier, related wor

High intensity 5 eV O-atom exposure facility for material degradation studies

An atomic oxygen exposure facility was developed for studies of material degradation. The goal of these studies is to provide design criteria and information for the manufacture of long life (20 to 30 years) construction materials for use in low Earth orbit. The studies that are being undertaken will provide: (1) absolute reaction cross sections for the engineering design problems, (2) formulations of reaction mechanisms for use in the selection of suitable existing materials and the design of new more resistant ones, and (3) the calibration of flight hardware (mass spectrometers, etc.) in order to directly relate experiments performed in low Earth orbit to ground based investigations. The facility consists of a CW laser sustained discharge source of O-atoms, an atomic beam formation and diagnostics system, a spinning rotor viscometer, and provision for using the system for calibration of actual flight instruments