Radiation Damage and Recovery Properties of Common Plastics PEN (Polyethylene Naphthalate) and PET (Polyethylene Terephthalate) Using a 137Cs Gamma Ray Source Up To 1 MRad and 10 MRad

Polyethylene naphthalate (PEN) and polyethylene teraphthalate (PET) are cheap and common polyester plastics used throughout the world in the manufacturing of bottled drinks, containers for foodstuffs, and fibers used in clothing. These plastics are also known organic scintillators with very good scintillation properties. As particle physics experiments increase in energy and particle flux density, so does radiation exposure to detector materials. It is therefore important that scintillators be tested for radiation tolerance at these generally unheard of doses. We tested samples of PEN and PET using laser stimulated emission on separate tiles exposed to 1 MRad and 10 MRad gamma rays with a 137Cs source. PEN exposed to 1 MRad and 10 MRad emit 71.4% and 46.7% of the light of an undamaged tile, respectively, and maximally recover to 85.9% and 79.5% after 5 and 9 days, respectively. PET exposed to 1 MRad and 10 MRad emit 35.0% and 12.2% light, respectively, and maximally recover to 93.5% and 80.0% after 22 and 60 days, respectively

The relationship between risk and the respondent\u27s level of socialization in the military

The following thesis deals with a sensitive issue, namely the examination of risk-taking behaviors in a military context. Generally, it is agreed that certain decisions made by the military are considerably more vast and important (in terms of the sociopolitical, and moral ramifications) than decisions reached by non-military groups. In light of this agreement, any analysis of risk-taking behavior could be interpreted as threatening to the image of the military. Understanding the sensitivity of the central theme of the following thesis demands an understanding of the assumptions of the investigation. The two major assumptions of this work are: a) the military is not a mindless, thrill-seeking entity lacking in rational restraint, but the military socialization process does seem to elicit risk y behaviors from its members; and b) the military risk ethic is not necessarily any more dramatic than the civilian risk ethic, even though this relationship has not been tested in the literature of group behaviors. I am not, in other words, launching an attack on the rationality of military decision-making. With the above mentioned assumptions in mind, the analysis of socialization and risk in a military context will be developed throughout the following thesis

Biological and toxicological investigations of Chicago area navigation projects

unpublishednot peer reviewe

Conceptual designs study for a Personnel Launch System (PLS)

A series of conceptual designs for a manned, Earth to Low Earth Orbit transportation system was developed. Non-winged, low L/D vehicle shapes are discussed. System and subsystem trades emphasized safety, operability, and affordability using near-term technology. The resultant conceptual design includes lessons learned from commercial aviation that result in a safe, routine, operationally efficient system. The primary mission for this Personnel Launch System (PLS) would be crew rotation to the SSF; other missions, including satellite servicing, orbital sortie, and space rescue were also explored

High Performance Green LEDs by Homoepitaxial

This work's objective was the development of processes to double or triple the light output power from green and deep green (525 - 555 nm) AlGaInN light emitting diode (LED) dies within 3 years in reference to the Lumileds Luxeon II. The project paid particular effort to all aspects of the internal generation efficiency of light. LEDs in this spectral region show the highest potential for significant performance boosts and enable the realization of phosphor-free white LEDs comprised by red-green-blue LED modules. Such modules will perform at and outperform the efficacy target projections for white-light LED systems in the Department of Energy's accelerated roadmap of the SSL initiative