Reusable Cryogenic Tank VHM Using Fiber Optic Distributed Sensing Technology

The reusable oxygen and hydrogen tanks are key systems for both the X-33 (sub-scale, sub-orbital technology demonstrator) and the commercial Reusable Launch Vehicle (RLV). The backbone of the X-33 Reusable Cryogenic Tank Vehicle Health Management (VHM) system lies in the optical network of distributed strain temperature and hydrogen sensors. This network of fiber sensors will create a global strain and temperature map for monitoring the health of the tank structure, cryogenic insulation, and Thermal Protection System. Lockheed Martin (Sanders and LMMSS) and NASA Langley have developed this sensor technology for the X-33 and have addressed several technical issues such as fiber bonding and laser performance in this harsh environment

Dark matter and Modified Newtonian Dynamics in a sample of high-redshift galaxy clusters observed with Chandra

We compare the measurement of the gravitational mass of 38 high-redshift galaxy clusters observed by Chandra using Modified Newtonian Dynamics (MOND) and standard Newtonian gravity. Our analysis confirms earlier findings that MOND cannot explain the difference between the baryonic mass and the total mass inferred from the assumption of hydrostatic equilibrium. We also find that the baryon fraction at $r_{2500}$ using MOND is consistent with the Wilkinson Microwave Anisotropy Probe (WMAP) value of $\Omega_{B}/\Omega_{M}$Comment: New Astronomy in pres

Materials for engine applications above 3000 deg F: An overview

Materials for future generations of aeropropulsion systems will be required to perform at ever-increasing temperatures and have properties superior to the current state of the art. Improved engine efficiency can reduce specific fuel consumption and thus increase range and reduce operating costs. The ultimate payoff gain is expected to come when materials are developed which can perform without cooling at gas temperatures to 2200 C (4000 F). An overview is presented of materials for applications above 1650 C (3000 F), some pertinent physical property data, and the rationale used: (1) to arrive at recommendations of material systems that qualify for further investigation, and (2) to develop a proposed plan of research. From an analysis of available thermochemical data it was included that such materials systems must be composed of oxide ceramics. The required structural integrity will be achieved by developing these materials into fiber-reinforced ceramic composites

Skill uncertainty, skill accumulation, and occupational choice.

Abstract Workers entering the labor market are uncertain about their skill set. Standard human capital theory assumes workers have perfect information about their skills. In this paper, I argue that skill uncertainty can explain one type of worker moves that standard human capital theory cannot: moves between jobs where they perform different kinds of tasks. I consider workers who have a multi-dimensional bundle of labor market skills and begin their careers uncertain about their skill levels. I construct a model that links learning about skills to the tasks performed in jobs: the more intensely a job uses a particular skill, the more the workers learn about their true level of that skill. The model also contains a skill accumulation motive: as workers use a skill they gain additional amounts of it. A simplified version of the model suggests that if skill uncertainty were the dominant force workers would switch between jobs that use skills in different ratios but similar total levels. On the other hand, if skill accumulation were the dominant force they would switch between jobs that use similar ratios of skills but higher total levels. Linking data on workers from the National Longitudinal Study of Youth 1979 with occupational characteristics from the US Department of Labor O*NET database, I show that worker mobility across different task mixes is common and I estimate the model parameters. The current results indicate that skill uncertainty explains approximately 30% of worker mobility across different task ratios.

The Ursinus Weekly, November 12, 1962

Curtain Club\u27s Mr. & Mrs. North scheduled to open Friday evening • Founders Day salutes college • Debaters score in recent matches • Hinduism topic of IRC speaker tonight • Color film to highlight Bible study meeting • Chamberlin views Christian faith • Junior class dance • Lesley Frost to discuss poetry Wednesday in Forum appearance • Reed and Hendrixson elected to MSGA • Science groups begin tutoring service • Ursinus hockeywomen distinguished with all-college team honors • Larry Coon declared winner in semester\u27s cigarette contest • Zucker defeated in bid for state senate • Editorial: Congratulations, hockey team; Up with the drug! • Vice-president Wagner discusses publicity policy of the college • Humor, informality mark Kirkpatrick • Letters to the editor • Mohammed tells Weekly of summer experiences • Football team downed 20-12 in Lebanon Valley mud bath • Ups & downs of the soccermen • Brothers Brackin soccer standouts • Hockey squad finishes season with perfect record of 6 winshttps://digitalcommons.ursinus.edu/weekly/1280/thumbnail.jp