An Analysis of the Full-Floating Journal Bearing

An Analysis of the Full-Floating Journal Bearing

Date: January 28, 1947
Creator: Shaw, M.C. & Nussdorfer, T.J.
Description: An analysis of the operating characteristics of a full-floating bearing - a bearing in which a floating sleeve is located between the journal and bearing surfaces - is presented together with charts - from which the performance of such bearings may be predicted. Examples are presented to illustrate the use of these charts and a limited number of experiments conducted upon a glass full-floating bearing to verify some results of the analysis are reported. The floating sleeve can operate over a wide range of speeds for a given shaft speed, the exact value depending principally upon the ratio of clearances and upon the ratio of radii of the bearing. Lower operating temperatures at high rotative speeds are to be expected by using a full-floating bearing. This lower operating temperature would be obtained at the expense of the load-carrying capacity of the bearing if, for comparison, the clearances remain the same in both bearings. A full-floating bearing having the same load capacity as a conventional journal bearing may be designed if decreased clearances are allowable.
Contributing Partner: UNT Libraries Government Documents Department
Performance of Compressor of XJ-41-V Turbojet Engine II - Static-Pressure Ratios and Limitation of Maximum Flow at Equivalent Compressor Speed of 8000 rpm

Performance of Compressor of XJ-41-V Turbojet Engine II - Static-Pressure Ratios and Limitation of Maximum Flow at Equivalent Compressor Speed of 8000 rpm

Date: January 1, 1948
Creator: Dildine, Dean M. & Arthur, W. Lewis
Description: At the request of the Air Material Command, Army Air Forces, an investigation was conducted by the NACA Cleveland laboratory to determine the performance characteristics of the compressor of the XJ-41-V turbojet engine. This report is the second in a series presenting the compressor performance and analysis of flow conditions in the compressor. The static-pressure variation in the direction of flow through the compressor and the location and the cause of the maximum flow restriction at an equivalent speed of 8000 rpm are presented. After the initial runs were reported, the leading edges of the impeller blades and the diffuser surfaces were found to have been roughened by steel particles from a minor failure of auxiliary equipment. The leading edges of the impeller blades were refinished and all high spots resulting from scratches in the diffuser and the accessible parts of the vaned collector passages were removed. The initial overall performance and that obtained with the refinished blades are presented.
Contributing Partner: UNT Libraries Government Documents Department
Performance of Compressor XJ-41-V Turbojet Engine I - Preliminary Investigation at Equivalent Compressor Speed of 8000 RPM

Performance of Compressor XJ-41-V Turbojet Engine I - Preliminary Investigation at Equivalent Compressor Speed of 8000 RPM

Date: January 1, 1948
Creator: Ginsburg, Ambrose & Creagh, John W.R.
Description: At the request of the Air Material Command, Arm Air Forces, an investigation was conducted at the NACA Cleveland laboratory to determine the performance characteristics of the XJ-41-V turbojet-engine compressor. The complete compressor was mounted on a collecting chamber having an annular air-flow passage simulating the burner annulus of the engine and was driven by an electric motor. The compressor was extensively instrumented to determine the overall performance of the compressor, the characteristic performance of each of the compressor components, the state of the air stream in the simulated burner annulus, and the operation of the compressor bearings. An initial investigation at an equivalent compressor speed of 8000 rpm was made to determine the performance of the compressor and the collecting chamber and to determine the similarity of the air stream at the entrance to the simulated burner annulus. The mechanical performance of the compressor over a range of actual compressors speeds from 3300 to 8000 rpm is reported.
Contributing Partner: UNT Libraries Government Documents Department
Astrophysical Equation of State and Opacity

Astrophysical Equation of State and Opacity

Date: August 31, 1998
Creator: Dappen, W. & Guzik, J.A.
Description: No abstract prepared.
Contributing Partner: UNT Libraries Government Documents Department
Real-Time Risk and Fault Management in the Mission Evaluation Room for the International Space Station

Real-Time Risk and Fault Management in the Mission Evaluation Room for the International Space Station

Date: May 30, 2003
Creator: Nelson, W.R. & Novack, S.D.
Description: Effective anomaly resolution in the Mission Evaluation Room (MER) of the International Space Station (ISS) requires consideration of risk in the process of identifying faults and developing corrective actions. Risk models such as fault trees from the ISS Probabilistic Risk Assessment (PRA) can be used to support anomaly resolution, but the functionality required goes significantly beyond what the PRA could provide. Methods and tools are needed that can systematically guide the identification of root causes for on-orbit anomalies, and to develop effective corrective actions that address the event and its consequences without undue risk to the crew or the mission. In addition, an overall information management framework is needed so that risk can be systematically incorporated in the process, and effectively communicated across all the disciplines and levels of management within the space station program. The commercial nuclear power industry developed such a decision making framework, known as the critical safety function approach, to guide emergency response following the accident at Three Mile Island in 1979. This report identifies new methods, tools, and decision processes that can be used to enhance anomaly resolution in the ISS Mission Evaluation Room. Current anomaly resolution processes were reviewed to identify requirements for effective ...
Contributing Partner: UNT Libraries Government Documents Department
Long Term Oxidation of Model and Engineering TiAl Alloys

Long Term Oxidation of Model and Engineering TiAl Alloys

Date: August 24, 2001
Creator: Locci, IE
Description: The purpose of this research was to characterize the oxidation behavior of several model (TiAl, TiAl-Nb, TiAl-Cr, TiAl-Cr-Nb) and engineering alloys (XD, K5, Alloy 7, WMS) after long-term isothermal exposure ({approx}7000 h) at 704 C, and after shorter time exposure ({approx}1000 h) at 800 C in air. High-resolution field emission and microprobe scanning electron microscopy were used to characterize the scales formed on these alloys. Similarities and differences observed in the scales are correlated with the various ternary and quaternary microalloying additions.
Contributing Partner: UNT Libraries Government Documents Department
An evaluation of the 1997 JPL Summer Teacher Enhancement Program

An evaluation of the 1997 JPL Summer Teacher Enhancement Program

Date: October 20, 1997
Creator: Slovacek, Simeon P. & Doyle-Nichols, Adelaide R.
Description: There were two major components in the Jet Propulsion Laboratory (JPL) Summer Teacher Enhancement Project (STEP). First, the Summer Institute was structured as a four-week, 4-credit-unit University course for middle school science teachers, and consisted of workshops, lectures, labs, and tours as activities. The second component consists of follow-up activities related to the summer institute's contents, and again is structured as a University credit-bearing course for participants to reinforce their summer training. Considerable information from the comments and course ratings as given by the participants is included.
Contributing Partner: UNT Libraries Government Documents Department
Proton radiation damage in P-channel CCDs fabricated on high-resistivity silicon

Proton radiation damage in P-channel CCDs fabricated on high-resistivity silicon

Date: July 28, 2002
Creator: Bebek, C.; Groom, D.; Holland, S.; Karcher, A.; Kolbe, W.; Lee, J. et al.
Description: P-channel, backside illuminated silicon CCDs were developed and fabricated on high-resistivity n-type silicon. Devices have been exposed up to 1x1011 protons/cm2 at 12 MeV. The charge transfer efficiency and dark current were measured as a function of radiation dose. These CCDs were found to be significantly more radiation tolerant than conventional n-channel devices. This could prove to be a major benefit for long duration space missions.
Contributing Partner: UNT Libraries Government Documents Department
Proton radiation damage in high-resistivity n-type silicon CCDs

Proton radiation damage in high-resistivity n-type silicon CCDs

Date: December 20, 2001
Creator: Bebek, C.J.; Groom, D.E.; Holland, S.E.; Karcher, A.; Kolbe, W.F.; Lee, J. et al.
Description: A new type of p-channel CCD constructed on high-resistivity n-type silicon was exposed to 12 MeV protons at doses up to 1x1011 protons/cm2. The charge transfer efficiency was measured as a function of radiation dose and temperature. We previously reported that these CCDs are significantly more tolerant to radiation damage than conventional n-channel devices. In the work reported here, we used pocket pumping techniques and charge transfer efficiency measurements to determine the identity and concentrations of radiation induced traps present in the damaged devices.
Contributing Partner: UNT Libraries Government Documents Department
The response of a spherical tissue-equivalent proportional counter to different ions having similar LET.

The response of a spherical tissue-equivalent proportional counter to different ions having similar LET.

Date: September 8, 2003
Creator: Guetersloh, S.; Borak, T.; Taddei, P.; Zeitlin, C.; Heilbronn, L.; Miller, J. et al.
Description: No abstract prepared.
Contributing Partner: UNT Libraries Government Documents Department
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