A Study of Proton Induced Effects on Reflective Surfaces of Space Mirrors

Proton radiation effects at synchronous earth orbits on telescope mirror reflective surfaces and substrate

Plasma cleaning device

High vacuum cleaning of contaminated surfaces such as hydrocarbon containment films can be accomplished by a plasma cleaning device which includes a plasma discharge housing to permit generation of a plasma in an environment having a higher pressure than the surface which is to be cleaned. A ground electrode and a radio frequency electrode partially surround a quartz plasma tube, for the introduction of an ionizable gas. These electrodes ionize the gas and help generate the plasma. This plasma flows through a non-constrictive aperture, through the plasma discharge housing and then on to the contaminated surface

If at first you don't succeed: an experimental investigation of the impact of repetition options on corporate takeovers

This paper models, and experimentally simulates, the free-rider problem in a takeover when the raider has the option to “resolicit,” that is, to make a new offer after an offer has been rejected. In theory, the option to resolicit, by lowering offer credibility, increases the dissipative losses associated with free riding. In practice, the outcomes of our experiment, while quite closely tracking theory in the effective absence of an option to resolicit, differed dramatically from theory when a significant probability of resolicitation was introduced: The option to resolicit reduced the costs of free riding fairly substantially. Both the raider offers and the shareholder tendering responses generally exceeded equilibrium predictions.Corporations - Finance ; Game theory

Active cleaning technique for removing contamination from optical surfaces in space

Plasma cleaning experiments were completed on hydrocarbon contaminant films, experiments were initiated to determine a satisfactory technique for depositing contaminant films, and an experiment was conducted to determine whether specimens are being thermally cleaned rather than plasma cleaned. Results of plasma cleaning experiments on hydrocarbon contaminant films showed that the optical properties of mirrors and gratings could be satisfactorily restored. Results on fused silica optical flats were inconclusive because of the insensitivity of measurement techniques to the contaminant films. White thermal control surfaces, degraded by the hydrocarbon contaminant film, could not be restored by oxygen plasma exposure. The reflectance of silvered FEP Teflon thermal control surfaces could be restored by plasma cleaning. Experiments with a silicone contaminant indicated that it could not be easily polymerized onto surfaces with ultraviolet radiation. Results of the thermal cleaning experiment showed that the polymerized hydrocarbon contaminant film could not be removed by heating in vacuum to a temperature in excess of that expected during plasma cleaning

Fabrication of lightweight parabolic concentrators from a glass master Final report

Forming of optical lightweight solar concentrator on glass master - spray technique for resin substrate layer

Laboratory demonstration model: Active cleaning technique device

The technique which utilizes exposure to a plasma to remove contaminants from a surface was incorporated into a laboratory model which demonstrates active cleaning by both plasma cleaning and ion sputtering modes of operation. The development phase is reported and includes discussion of the plasma tube configuration, device design, and performance tests. A general description of the active cleaning device is provided which includes information on the main power/plasma discharge sensors, and the power, gas supply, and ion accelerator systems. Development of the active cleaning species at high vacuum conditions is described and results indicate that plasma cleaning occurs in the region of a visible plume which extends from the end of the plasma tube. Recommendations are made for research to determine the plasma cleaning mechanism and the plasma species responsible for the cleaning, as well limitations on the type of contaminants that can be removed

The Best is the Enemy of the Good

When I began my residency, I wanted to deepen my clinical expertise so I could better serve the growing population of older adults. I thought my perfectionism would be an asset in this process and help me be successful. As a high achiever, I focused on meeting internal and external expectations, not on growth. What I did not think of was how to better myself as a person—or that I even needed to do so. I did not know that perfectionism can be a weakness that affects not only me but also those around me. I am not alone in my perfectionism as a healthcare professional. Research shows that perfectionism can lead to depression in nurses; negative feelings including guilt, fear, and shame in emergency medicine physicians after a medical error; and difficulty in receiving feedback and challenges in interpersonal relationships among physicians. Just as muscles require an overload stimulus to increase strength, I needed the pressure of residency to make changes in myself that bettered me as a person—and in turn benefited my roles as a physical therapist, coworker, spouse, teacher, and researcher

Cooperating to Resist Coercion: An Experimental Study

This study sheds light on the difficulties people face in cooperating to resist coercion. We adapt a threshold public goods game to investigate whether people are able to cooperate to resist coercion despite individual incentives to free-ride. Behavior in this resistance game is similar to that observed in multi-period public goods games. Specifically, we observe "out-of-equilibrium" outcomes and a decrease in successful resistance in later periods of a session compared to earlier ones. Nevertheless, cooperation remains relatively high even in the later periods. Finally, we find that increasing the resistance threshold has a substantial negative effect on the probability of successful resistance.

Active cleaning technique for removing contamination from optical surfaces in space

An active cleaning technique for removing contaminants from optical surfaces in space was investigated with emphasis on the feasibility of using plasma exposure as a means of in-situ cleaning. The major work accomplished includes: (1) development of an in-situ reflectometer for use in conjunction with the contaminant film deposition/cleaning facility; (2) completion of Apollo Telescope Mount (ATM) filter treatment experiments to assess the effects of plasma exposure on the UV transmittance; (3) attempts to correlate the atomic oxygen flux with cleaning rate; (4) completion of in-situ butadien contamination/plasma cleaning/UV reflectance measurement experiments; (5) carbon cleaning experiments using various gases; (6) completion of silicone contamination/cleaning experiments; and (7) experiments conducted at low chamber pressures to determine cleaning rate distribution and contamination of surfaces adjacent to those being cleaned

Trading institutions and price discovery: the cash and futures markets for crude oil

We provide substantial evidence that the futures market for West Texas Intermediate crude oil increased the short-term volatility of the cash price of crude oil. We show that the variability of prices increased using both published posted prices and transaction prices for producers. This increased volatility in the price of crude oil may reflect information aggregated into the price, an increase the variance of shocks to the price of crude oil, or noise in the futures price that affects the cash price. We present evidence from experiments consistent with the interpretation that information aggregation not feasible in a posted-price market can explain at least part of the increase in variance. This evidence supports the proposition that information not previously aggregated into the cash price for crude oil is at least part of the reason for the greater variability of the cash price after the opening of the futures market and provides at least one example in which a futures market increased the volatility of the cash market, and prices became more efficient.