73,102 research outputs found
The -string spectrum
We study the spectrum of strings. In particular, we show that for
appropriately chosen space-time signature, one of the scalar fields is singled
out by the spin-3 constraint and is ``frozen'': no creation operators from it
can appear in physical states and the corresponding momentum must assume a
specific fixed value. The remaining theory is unitary and resembles an ordinary
string theory in with anomalies cancelled by appropriate background
charges. In the case of the string, however, the spin-two ``graviton'' is
massive.Comment: 14 Page
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Plethodon yonahlossee
Number of Pages: 2Place of Publication: Kensington, MarylandIntegrative BiologyGeological Science
Pope Pius XII to the Guild of St. Luke
EDITOR\u27S NOTE: The address of Pope Pius XII, given November 12, 1944, to the Italian Guild of St. Luke, was perhaps the most comprehensive of all of his talks on medical morality. Moreover, it seems to have been the first of his many discourses to the medical profession; and it contained in germ many of the subsequent and very important addresses. We believe that all Catholic doctors should be familiar with its content; hence, we are presenting here a very complete digest of the Pope\u27s words. This has been made possible through the generous cooperation of Daniel T. Costello, S.J.; Mario Jaccarini, S.J.; and Richard J. McPartlin, S.J
A synopsis of the weather problems facing today's general aviation pilots
Concentration on weather to data has primarily been at the point of observation. There have been efforts to obtain and disseminate en route weather through pilot reports (PIREPS), but the efforts have been meager. What is needed is the cooperative efforts on the application of technology to the acquisition and dissemination of the en route weather data for those pilots in the air as well as those who are flight planning on the ground. A comprehensive three-dimensional computer storage system is proposed that receives weather information from all aircraft on IFR flight plans and stores this information by altitude and geographic coordinates. Also, a report on the Federal Aviation Administration's Research Engineering and Development Aviation Weather Program from the aspect of past, present and future is given
A Message to the Sick: His Holiness Pope Pius XII: Radio Message on the Day of the Sick, February 14 the Marian Year
Happy 21st birthday sport education: Where are we now?
The article focuses on the pros and cons of the Sport Education Curriculum (SEM) that is used in New Zealand. Comments made by former professional rugby player Chris Laidlaw show how important sport is to New Zealanders. Educator Daryl Siedentop believed that sport education was necessary and his play theory is analyzed
Areas of Seal R/D at GE
About four years ago, work was completed on a 36 inch diameter gas to gas carbon ring seal used to buffer low pressure turbine air at the rim of the forward outer flowpath on the GE36 unducted fan (UDF) engine. At about the same time, we were developing a long life counter-rotating intershaft air-oil seal of approximately 7.6 inch diameter for operation at 800 fps, 800 F, and 50 psid. Although we were successful in meeting most program goals with a split ring seal of the axial bushing type, the seal with the greatest payoff in life and air leakage rates, bearing many features in common with the GE36 seal, could not be successfully tested because of the structural weakness of the primary seal ring carbon material. This was a split ring seal using a hybrid combination of orifice compensated hydrostatic and shrouded hydrodynamic gas bearings. We are presently working to develop this design in conjunction with high strength materials being developed by Pure Carbon Co. In the area of engine secondary gas flow path-sealing for performance improvement, we are currently working with carbon and all metal face seals. A 15 inch diameter all metal 'aspirating' face seal, using self-acting hydrostatic bearings, was successfully tested to 700 fps, 100 psid, and 1000 F, demonstrating long life at flow reduction of 86 percent compared to a 'best' labyrinth. This seal will be developed through 1400 F, 900 fps, and 350 psid. The seal 'aspirates' closed at about idle speed pressure during engine start and reopens at engine shutdown. A hydraulic thrust balance seal, currently using orifice compensated hydrostatics, is under development. Other aspects of these projects are briefly covered
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