| 出版: | Washington, D.C. : [Springfield, Va. : National Aeronautics and Space Administration ; For sale by the National Technical Information Service] |
| 附註: | Prepared at Langley Research Center. N71-34164 Cover title. Includes bibliographical references (p. 19). |
| 出版: | Washington, D.C. : National Aeronautics and Space Administration : [For sale by the Office of Technical Services, Dept. of Commerce] |
| 附註: | Prepared at Langley Research Center. "September 1971."--Cover. Major NASA subject terms: Control simulation, real time operation, space stations, airborne/spaceborne computers, computer programs, control moment gyroscopes, digital computers, systems analysis. Includes bibliographical references (p. 32). A real-time computer-hardware simulation for the investigation of space station dynamics and control problems is described. The simulation utilizes full-scale control moment gyro (CMG) hardware mounted on a moving base simulator, a manual console, and a Control Data (CDC) 6600 digital computer to represent a space station and its control system. The digital computer software is programed in modular form by using separate subroutines or modules to represent the simulated spacecraft, onboard control computer, isolated experiment packages, and other disturbance or dynamics functions associated with space station operation. A complete functional and operational description of the major elements of the space station simulation is included. |
| 出版: | Washington, D.C. : Springfield, Va. : National Aeronautics and Space Administration ; For sale by the Clearinghouse for Federal Scientific and Technical Information |
| 附註: | Prepared at Lewis Research Center. "December 1971." Includes bibliographical references (p. 14-15). An analysis of time-mean-turbulent boundary layer velocity profiles measured in a rapidly accelerating flow suggests that the outer region of the velocity profiles consists of essentially inviscid, rotational flow. The extent of this inviscid outer region was observed in some cases to exceed 90 percent of what is ordinarily thought of as the turbulent boundary layer thickness. On the other hand, the inner frictional region of these velocity profiles appears to have turbulent characteristics similar to those of more conventional turbulent boundary layers. Hence, the outer edge boundary condition for this inner region is more properly the external rotational flow region than the free stream. |
| 出版: | Washington, D.C. : Springfield, VA : National Aeronautics and Space Administration ; For sale by the Clearinghouse for Federal Scientific and Technical Information |
| 附註: | Includes bibliographical references (p. 27-28). Qualitative comparison of oxidation resistance of nickel-aluminum alloys with additions of chromium, silicon, and titanium at high temperatures. |
| 出版: | Washington, D.C. : [For sale by the Clearinghouse for Federal Scientific and Technical, Springfield, Virginia 22151] : National Aeronautics and Space Administration |
| 附註: | Includes bibliographical references (p. 30). A FORTRAN V digital-computer program, capable of determining the nonlinear motion of two six-degree-of-freedom rigid bodies connected by shock struts and subjected to ground impact, is presented in this report. A sample problem is included to provide a correlation between computer results and actual test results. |
| 出版: | Washington, D.C. : National Aeronautics and Space Administration : [For sale by the Clearinghouse for Federal Scientific and Technical, Springfield, Virginia 22151] |
| 附註: | Includes bibliographical references (p. 24-25). This paper reports an experimental and analytical vibration study of free-free isotropic elliptical cylindrical shells of constant mass ranging in cross-sectional eccentricity from zero (circular shell) to 0.916. Experimental resonant frequencies, nodal patterns, and mode shapes were obtained by use of an air-jet shaker or an electrodynamic shaker with a noncontact inductance probe that could be moved over most of the shell surface. Experimental frequencies were in generally good agreement with analytical frequencies calculated by means of a Rayleigh-Ritz type of analysis featuring multiterm longitudinal and circumferential modal expansions. Frequencies for shells with eccentricity of 0.916 were as much as 40 percent below the corresponding circular-shell frequencies. As eccentricity increased, analytical and experimental mode shapes indicated considerable longitudinal and circumferential modal coupling. |
| 出版: | Washington, D.C. : National Aeronautics and Space Administration : [For sale by the Clearinghouse for Federal Scientific and Technical, Springfield, Virginia 22151] |
| 附註: | Includes bibliographical references (p. 29). Structural-efficiency analyses are used to determine the minimum-mass proportions of some panel configurations loaded in uniaxial compression. Five panel constructions, four of which incorporate circular-arc elements and the other a beaded-web corrugation, are shown to have improved structural efficiencies over conventional configurations. In addition to the structural-efficiency equations, which give the mass equivalent flat-plate thickness of the panel necessary to carry a given load, related design equations for calculating the cross-sectional dimensions of these minimum-mass panels are presented. The upper and lower limits of loading, where the design constraints of minimum gage or material yield strength become the dominant design conditions, are established and the corresponding design equations which are applicable outside these limits are also presented. |
| 出版: | Washington, D.C. : National Aeronautics and Space Administration |
| 附註: | Prepared by Lewis Research Center. N72-13270 Includes bibliographical references (p. 30). The usual boundary-layer equations describing the steady-state mixing of parallel jets are supplemented by the momentum equation in the direction normal to the flow. This allows detailed computation of the flow field in the mixing region and simultaneous computation of the outer inviscid flow. An explicit and an implicit finite difference scheme have been developed and applied in several illustrative examples. The examples include mixing of planar and axisymmetric supersonic jets of different composition with both matched and unmatched static pressures. Numerical results were compared with available experimental data obtained for the unmatched pressure case. |
| 出版: | Washington, D.C. : U.S. Dept. of the Interior, Office of Saline Water |
| 附註: | "Contract 14-30-2849." "Int-OSW-RDPR-71-733." "December 1971." |
| 出版: | Washington, D.C. : National Aeronautics and Space Administration : [For sale by the Clearinghouse for Federal Scientific and Technical, Springfield, Virginia 22151] |
| 附註: | Includes bibliographical references (p. 31). A discrete steepest ascent method which allows controls which are not piecewise constant (for example, it allows all continuous piecewise linear controls) is derived for the solution of optimal programing problems. This method is based on the continuous steepest ascent method of Bryson and Denham and new concepts introduced by Kelley and Denham in their development of "compatible" adjoints for taking into account the effects of numerical integration. The method is a generalization of the algorithm suggested by Canon, Cullum, and Polak with the details of the gradient computation given. The discrete method is compared with the continuous method for an aerodynamics problem for which an analytic solution is given by Pontryagin's maximum principle, and numerical results are presented. The discrete method converges more rapidly than the continuous method at first, but then for some undetermined reason, loses its exponential convergence rate. A comparison is also made for the algorithm of Canon, Cullum, and Polak using piecewise constant controls. This algorithm is very competitive with the continuous algorithm. |
| 出版: | Washington, D.C. : Springfield, Va. : National Aeronautics and Space Administration ; For sale by the National Technical Information Service [distributor] |
| 附註: | "NASA CR-1766." Performing organization report no.: FTU Report No. 5501 "July 1971." Cover title. Includes bibliographical references (p. 31) This report investigates the minimum weight design of axially compressed ring and stringer stiffened cylindrical shells. Also available online from the NASA Technical Reports Server (http://ntrs.nasa.gov/). Address as of 01/27/06: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710020642%5f1971020642.pdf. Prepared by Florida Technological University, Orlando, Fla. for Langley Research CenterNGR 10-019-002;722-02-10-05 |
| 出版: | Washington, D.C. : Agricultural Research Service, U.S. Dept. of Agriculture |
| 出版: | [Washington, D.C.] : U.S. Dept. of the Interior, Office of Saline Water |
| 附註: | "December, 1971." Contract No. 14-01-0001-2248 |
| 出版: | Washington, D.C. : National Aeronautics and Space Administration : [For sale by the Clearinghouse for Federal Scientific and Technical, Springfield, Virginia 22151] |
| 附註: | Includes bibliographical references (p. 31). Any prior information an experimenter has should be incorporated into the design of further experiments. Assume such information is expressed as probabilities that each parameter of the full factorial model is nonzero. This report develops optimal design procedures by posing the experimental design problem as a finite decision problem. Bays and mini-max design strategies are then derived and their application illustrated. The major computational step is the evaluation of all possible matchings of physical variables to the abstract variables of all potential designs. The technique of telescoping sequences of blocks permits the consideration of experiments to be performed in stages. |
| 出版: | Washington, D.C. : Springfield, Va. : National Aeronautics and Space Administration ; For sale by the Clearinghouse for Federal Scientific and Technical Information |
| 附註: | Prepared by Langley Research Center. "November 1971." N72-10964 Includes bibliographical references (p. 46). Simplified dynamic models were applied in a study of vibration in a high-speed railroad car. The mathematical models used were a four-degree-of-freedom model for vertical responses to vertical rail inputs and a ten-degree-of-freedom model for lateral response to lateral or rolling (cross-level) inputs from the rails. Elastic properties of the passenger car body were represented by bending and torsion of a uniform beam. Rail-to-car (truck) suspensions were modeled as spring-mass-dashpot oscillators. Lateral spring nonlinearities approximating certain complicated truck mechanisms were introduced. The models were excited by displacement and, in some cases, velocity inputs from the rails by both deterministic (including sinusoidal) and random input functions. Results were obtained both in the frequency and time domains. Solutions in the time domain for the lateral model were obtained for a wide variety of transient and random inputs generated on-line by an analog computer. Variations in one of the damping properties of the lateral car suspension gave large fluctuations in response over a range of car speeds for a given input. This damping coefficient was significant in reducing lateral car responses that were higher for nonlinear springs for three different inputs. |
| 出版: | Washington, D.C. : U.S. Dept. of Commerce, National Bureau of Standards |
| 附註: | Includes bibliographical references (p. 65-67, 77). Sponsored by Naval Air Engineering CenterProject Order 9-8029 |
| 出版: | Washington, D.C. : Defense Mapping Agency, Hydrographic/Topographic Center |
| 附註: | Issued by: United States. Naval Oceanographic Office, 1971; Defense Mapping Agency. Hydrographic Center, 1972- ?; Defense Mapping Agency. Hydrographic/Topographic Center, 1991?- Issued in conjunction with Sailing directions (enroute) for the Western Mediterranean; Sailing directions (enroute) for the Eastern Mediterranean. |
| 出版: | Washington : U.S. Govt. Print. Off. |
| 附註: | Includes bibliographical references. |
| 出版: | [New York] : Arno Press |
| ISBN: | 0405028296 |
| 出版: | White Oak : |
| 附註: | Caption title. no. 1. Aerodynamic design. |
| 出版: | Washington : U.S. Govt. Print. Off. |
| 附註: | Includes index. "NAVPERS 10120-F" Cover title. |
| 出版: | Washington, D.C. : U.S. Environmental Protection Agency |
| 附註: | Thesis (M.S.)--The University of Michigan, 1971 |
| 出版: | Washington : |
| 出版: | Washington, D.C. : National Aeronautics and Space Administration |
| 附註: | Prepared at Marshall Space Flight Center. Cover title. "N72-10360." Includes bibliographical references (p. 30-31). High resolution accelerometer measurements in the altitude region 140 to 300 km from a satellite in a near-polar orbit during a period of extremely high geomagnetic activity indicate that Joule heating is the primary source of energy for atmospheric heating associated with geomagnetic activity. This conclusion is supported by the following observational evidence: (1) There is an atmospheric response in the auroral zone which is nearly simulataneous with the onset of geomagnetic activity, with no significant response in the equatorial region until several hours later; (2) The maximum heating occurs at geographic locations near the maximum current of the auroral electrojet; and (3) There is evidence of atmospheric waves originating near the auroral zone at altitudes where Joule heating would be expected to occur. An analysis of atmospheric response time to this heat shows time delays are apparently independent of altitude but are strongly dependent upon geomagnetic latitude. |
| 出版: | Washington, D.C. : National Aeronautics and Space Administration |
| 附註: | Prepared by AVCO Corporation, Systems Division, for Langley Research Center. N72-10401 Includes bibliographical references (p. 249-250). |
| 出版: | Washington, D.C. : Springfield, VA : National Aeronautics and Space Administration ; For sale by the Clearinghouse for Federal Scientific and Technical Information |
| 附註: | Prepared at Flight Research Center. N71-36672 Includes bibliographical references (p. 35). In the validation of the general purpose airborne simulator, certain motion and visual cues could not be duplicated because the airborne simulator could not be independently controlled in six degrees of freedom. According to pilot opinion (NASA TN D-6431), however, the XB-70 airplane at two flight conditions had been simulated satisfactorily. Because of the dependence of simulation results on simulator configuration, two areas were investigated after the validation program was completed. The first was the effect of mismatched cues on observed handling qualities. Experiments which varied lateral acceleration at the pilot's location and yaw rate, while keeping constant the lateral-directional dynamics displayed on the pilot's instruments, showed pilot sensitivity to directional motion cues to be different for the simulation of two XB-70 flight conditions. A technique for allowing consecutive evaluations of moving- and fixed-base configurations in flight was used successfully to determine motion cue effects. The second area investigated was the measurement and description of simulation fidelity. In-flight frequency-response measurements of the model-following system were taken to examine model-following fidelity for directly matched variables such as sideslip and roll rate as well as uncontrolled parameters such as lateral acceleration. |
| 出版: | Washington, D.C. : [Springfield, Va. : National Aeronautics and Space Administration ; For sale by the National Technical Information Service] |
| 附註: | Research prepared at Lewis Research Center. Cover title. Bibliography: p. 8-9 Mechanical contacts with polytetrafluoroethylene (PTFE) and polyimide polymer (PI) contacting tungsten field ion microscope emitter tips were conducted in vacuum. The metal polymer interface was examined on an atomic scale by helium field ion microscopy. Mechanical transfer was observed upon simple touch contact of the polymer materials to tungsten. The transferred polymers were stable even at the high field necessary for helium ionization, thus implying a strong chemical bonding to the metal surface. The mechanical contact stresses orient the transferred material on the tungsten surface in a radial manner from the center of contact. With sufficient load the PTFE and PI cause deformation of the tungsten. On the tungsten (110) plane, individual molecular clusters can be resolved. |
| 出版: | [Washington, D.C.] : U.S. Dept. of the Interior, Bureau of Mines |
| 附註: | Bibliography: p. 11 |
| 出版: | Washington, DC : U.S. G.P.O. |
| 出版: | Lehre : New York : J. Cramer ; Stechert-Hafner Service Agency |
| 附註: | Reprint. Originally published: Philadelphia : C. Sherman, 1862, 1874 Includes indexes. "An edition of the Musci, by W. S. Sullivant, occupying the pages 1-112 of this volume, was separately issued by the author ... Pages 113-204 ... were printed in the year 1862"--Note. Musci / by William S. Sullivant -- Lichenes / by Edward Tuckerman -- Algae / by J.W. Bailey and W.H. Harvey -- Fungi / by M.A. Curtis and M.J. Berkeley -- Phanerogamia of Pacific North America / by John Torrey [edited by Asa Gray]. |
| 出版: | Washington, DC : U.S. G.P.O. |
| 附註: | "Prepared for Advanced Research Projects Agency." Includes bibliographical references (leaves 563-566, v. 2) Photocopy.[Alexandria, Va.? :Defense Documentation Center, Defense Logistics Agency?,1971?]28 cm. |
| 出版: | Ann Arbor : |
| 附註: | "This publication is largely identical with the Survey Research Center report on a pilot study of residents in model neighborhoods which was submitted to the Urban Institute and to the Model Cities Administration in June 1970." Includes bibliographical references. |
| 出版: | Washington, D.C. : U.S. Dept. of the Interior ; For sale by the Supt. of Docs., U.S. Govt. Print. Off. |
| 附註: | "October 1971." "Contract No. 14-30-2724." Includes bibliographical references. |
| 出版: | [Washington, D.C.] : U.S. Dept. of Agriculture, [1971] |
| 附註: | Chiefly tables. |
| 出版: | [Washington : Dept. of the Army, Office of the Chief of Engineers |
| 附註: | Appendices issued separately. Cover title. |
| 出版: | Washington, D.C. : U.S. Dept. of the Interior |
| 附註: | Contract nos. 14-01-0001-1466, 14-01-0001-1684, 14-30-2591 "Int-OSW-RDPR-71-728." "May 1971." No longer available for sale by the Supt. of Docs. Bibliography: p. 86-87 |
| 出版: | Washington, D.C. : Economic Research Service, U.S. Dept. of Agriculture |
| 附註: | Prepared in cooperation with South Carolina Agricultural Experiment Station, Clemson University. Cover title. Bibliography: p. 70 |
| 出版: | [Rockville, Md.] : U.S. Solid Waste Management Office; [for sale by the Supt. of Docs., U.S. Govt. Print. Off., Washington] |
| 附註: | "Solid waste management series (SW-19c)" Prepared for the Solid Waste Management Office under contract no. PH 86-68-203 Includes bibliographical references. |
| 出版: | Washington : U.S. Dept. of Agriculture |
| 附註: | Cover title. Bibliography: p. 32-33 |
| 出版: | Portland, Ore. : Pacific Northwest Forest and Range Experiment Station, Forest Service, U.S. Dept. of Agriculture |
| 附註: | "May 1971." Caption title. Includes bibliographical references (p. 6). |
| 出版: | Washington, D.C. : Office, Chief of Engineers, Corps of Engineers |
| 出版: | [Washington] : Environmental Protection Agency |
| 附註: | Cover title. |
| 出版: | [S.l.] : Dept. of the Army, Corps of Engineers, North Central Division |
| 附註: | Cover title: Great Lakes Region inventory report : national shoreline study. |
| 出版: | [S.l.] : Dept. of the Army, Corps of Engineers, North Central Division |
| 附註: | Cover title: Great Lakes Region inventory report : national shoreline study. |
| 出版: | [Washington, D.C.] : Dept. of Transportation, Coast Guard |
| 附註: | Earlier eds. have titles: Recreational boating guide, and, Official U.S. Coast Guard recreational boating guide. "CG-340." Cover title. |
| 出版: | Norfolk, Va. : Navy Weather Research Facility |
| 出版: | Washington, D.C. : U.S. National Aeronautics and Space Administratration |
| 附註: | Includes bibliographical references. "August 1971." Nonlinear systems for matching input-output of mathematical model to physical system. |