| 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. 11-12). Differential-maximum-bubble-pressure apparatus used for surface tension measurements in air of liquid lubricants to 200 C. |
| 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. 132-136). A new algorithm is developed for estimating system parameters from input-output data. If the noise or uncertainty in the system is small, the algorithm does not require a prior estimate of the unknown parameters and if the noise has a zero mean, the final parameter estimates will not be biased. A method for reducing the computations required to obtain the parameter estimates is also presented. A general canonical realization is developed for multi-input, multioutput, constant-coefficient, linear equations. If the unknown system is modeled in its canonical form, the unknown parameters are uniquely identifiable. An analogy is established between a parameter estimation procedure developed by Shinbrot and the concept of linear observers developed by Luenberger. It is shown that observers of lower order can be designed quite easily using an extension of Shinbrot's method. |
| 出版: | Washington, D.C. : National Aeronautics and Space Administration : [For sale by the Clearinghouse for Federal Scientific and Technical, Springfield, Virginia 20230] |
| 附註: | Includes bibliographical references (p. 23). The characteristics of a parallel, ovcr-and-under. turbojet-ramjet propulsion system installed on an all-body Mach number 6 hypersonic aircraft are estimated, and the effect of variations in propulsion system parameters on payload and on problems of installation are determined. Engine thrust and fuel flow requirements are evaluated throughout acceleration and cruise, and the effects on the weights and dimensions of the propulsion system, including both inlets and engines, are determined. A wraparound turboramjet is also evaluated and comparisons with the parallel turbojet-ramjet system are made. System requirements: Adobe Acrobat Reader. [electronic resource] |
| 出版: | [Washington, D.C.] : U.S. Dept. of the Interior : For sale by the Supt. of Docs., U.S. G.P.O. |
| 附註: | "PB202770"--Cover. "Contract No. 14-01-0001-1810." Includes bibliographical references. Contract no. 14-01-0001-1810 |
| 出版: | [Washington, D.C.] : U.S. Dept. of Interior, Bureau of Mines |
| 附註: | "August 1971"--Cover. 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: | Prepared for Office of Saline Water under contract no. 14-01-0001-2299 Includes bibliographical references. |
| 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." N72-10958 Includes bibliographical references (p. 29-32). The effects of material damping on flutter of stressed rectangular panels are studied within the context of linear thermoelasticity theory. The closed-form expression for the thermoelastic (material) damping coefficient is obtained as a function of frequency, panel temperature and dimensions, and material properties. The solution of the stability boundary-value problem is obtained by use of a generalized Galerkin method in the cross-stream direction which reduces the governing partial differential equations to a system of ordinary differential equations in the streamwise direction. These equations are then solved exactly. Numerical results are given for the thermoelastic damping coefficients and for the flutter speeds of partially and fully clamped panels subjected to midplane stress. |
| 出版: | Washington, D.C. : [Springfield, Va. : National Aeronautics and Space Administration ; For sale by the National Technical Information Service |
| 附註: | Prepared at Lewis Research Center. "February 1971." Cover title. Includes bibliographical references (p. 15). A 27-inch (68.6-cm) long rectangular combustor segment consisting of an array of 48 combustor modules was tested to determine its performance. Each module mixed and swirled fuel with air and stabilized combustion. Test conditions were inlet temperatures of 600 [degree] and 1150 [degree] F (589 and 894 K), a pressure of 3 atmospheres, and reference velocities to 160 ft/sec (48.8 m/sec). Results were combustion efficiencies of 100 percent, a pressure loss of 5.4 percent for an inlet Mach number of 0.25, a heat release rate of 11.86x10 [power of six] Btu/(hr)(ft [power of three] )(atm) for a temperature ratio of 2.5, and pattern factor spans of 0.30 to 0.37 and 0.22 to 0.28 with 600 [degree] and 1150 [degree] F (589 and 894 K) inlet air temperatures, respectively. Altitude blowout and relight data, as well as a comparison of results with a longer combustor, are also included. System requirements: Adobe Acrobat Reader. [electronic resource] |
| 出版: | Washington, D.C. : National Aeronautics and Space Administration : [For sale by the Office of Technical Services, Dept. of Commerce] |
| 附註: | Prepared by Lewis Research Center. "November 1971."--Cover. Major NASA subject terms: Combustion chambers, combustion efficiency, jet engines, vertical takeoff aircraft, combustion control, combustion physics, performance tests. Includes bibliographical references (p. 18). |
| 出版: | Ogden, Utah : Intermountain Forest & Range Experiment Station, Forest Service, U.S. Dept. of Agriculture |
| 出版: | Washington, D.C. : National Aeronautics and Space Administration ; [For sale for Federal Scientific and Technical Information, Springfield, Virginia 22151] |
| 附註: | Includes bibliographical references (p. 8). Random numbers were generated with the aid of a digital computer and transformed such that the probability density function of a discrete random load history composed of these random numbers had one of the following non-Gaussian distributions: Poisson, binomial, log-normal, Weibull, and exponential. The resulting random load histories were analyzed to determine their peak statistics and were compared with cumulative peak maneuver-load distributions for fighter and transport aircraft in flight. |
| 出版: | Washington, D.C. : U.S. Govt. Print. Off. |
| 附註: | Contract no. 14-01-0001-2165 |
| 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. 37). Effect of static stress and edge restraint on vibration of nearly cylindrical shells with circular cross section and slight meridional curvature. |
| 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 Langley Research Center. N71-31435 Cover title. Includes bibliographical references (p. 29-30). Scattering of plane waves from thin rigid porous elliptic cylindrical shells and Mathieu function. |
| 出版: | Washington : National Aeronautics and Space Administration : [For sale by the Clearinghouse for Federal Scientific and Technical Information, Springfield, Va.] |
| 附註: | Prepared at Langley Research Center and Langley Directorate, U.S. Army Air Mobility R & D Laboratory. N 71-34028 Includes bibliographical references (p. 16). A wind-tunnel investigation has been conducted to determine the performance and static stability and control characteristics of an external-flow jet-flap transport configuration having inboard pod-mounted engines and full-span triple-slotted flaps. Tests were made with the engines mounted clustered at 22.0 percent and 30.4 percent semispan to represent double (Siamese) pods and with engines mounted at 22.0 percent and 41.7 percent semispan to represent a more spread arrangement. Tests were also made to evaluate the effectiveness of wing leading-edge blowing as a means of improving the aerodynamic efficiency of the configuration and of eliminating the large engine-out roll asymmetries that , occurred for the configuration when the wing with an engine out stalled first. |
| 出版: | [Washington, D.C.] : U.S. Dept. of Interior, Bureau of Mines |
| 附註: | Bibliography: p. 9 |
| 出版: | Washington : U.S. National Aeronautics and Space Administration |
| 附註: | A search for residual magnetism was made along the damage path of a strong tornado that passed through a residential section of Hazlehurst, Mississippi, on January 23, 1969. Over 3000 gauss-meter readings were taken on nailheads in 24 frame buildings at various points on both sides of the damage path, but no evidence of residual magnetism attributable to the tornado was found. A statistical analysis of the data from seven of the buildings showed that an upper bound on possible axial dc electric current in the tornado was 3900 amperes at touchdown and 6100 amperes during its most intense phase. Residual magnetism measurements also indicated that transient electric currents of about 135 and 300 amperes had occurred in ground wires connected to the electric-meter boxes on two buildings. This finding suggests that residual-magnetism measurements on nails may be useful for detecting possible magnetic fields from ball lightning and other sporadic electrical phenomena, since no prior instrumentation is required. |
| 出版: | Bethesda, Md. : Washington, D.C. : The Institutes ; For sale by the Supt. of Docs., U.S. Govt. Print. Off. |
| 附註: | Bibliography: p. 22 |
| 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). Resonant frequency measurement systems used in conjunction with open-ended microwave cavity to continuously monitor density of liquid hydrogen in flow system. |
| 出版: | Washington, D.C. : National Aeronautics and Space Administration |
| 附註: | N72-13518 Includes bibliographical references (p. 19). An algorithm employing a modified sequential random perturbation, or creeping random search, was applied to the problem of optimizing the parameters of a high-energy beam transport system. The stochastic solution of the mathematical model for first-order magnetic-field expansion allows the inclusion of state-variable constraints, and the inclusion of parameter constraints allowed by the method of algorithm application eliminates the possibility of infeasible solutions. The mathematical model and the algorithm were programmed for a real-time simulation facility; thus, two important features are provided to the beam designer: (1) a strong degree of man-machine communication (even to the extent of bypassing the algorithm and applying analog-matching techniques), and (2) extensive graphics for displaying information concerning both algorithm operation and transport-system behavior. Chromatic aberration was also included in the mathematical model and in the optimization process. Results presented show this method as yielding better solutions (in terms of resolutions) to the particular problem than those of a standard analog program as well as demonstrating flexibility, in terms of elements, constraints, and chromatic aberration, allowed by user interaction with both the algorithm and the stochastic model. Example of slit usage and a limited comparison of predicted results and actual results obtained with a 600 MeV cyclotron are given. |
| 出版: | Washington, D.C. : National Aeronautics and Space Administration ; [For sale for Federal Scientific and Technical Information, Springfield, Virginia 22151] |
| 附註: | Includes bibliographical references (p. 49). A numerical evaluation and an analysis of the effects of environmental disturbance torques on the attitude of a hexagonal cylinder rolling wheel spacecraft were performed. The resulting perturbations caused by five such torques were found to be very small and exhibited linearity such that linearized equations of motion yielded accurate results over short periods and the separate perturbations contributed by each torque were additive in the sense of superposition. Linearity of the torque perturbations was not affected by moderate system design changes and persisted for torque-to-angular momentum ratios up to 100 times the nominal expected value. As these conditions include many possible applications, similar linear behavior might be anticipated for other rolling-wheel spacecraft. |
| 出版: | Portland, Ore. : Pacific Northwest Forest and Range Experiment Station, Forest Service, U.S. Dept. of Agriculture |
| 附註: | "July 1971." Caption title. Includes bibliographical references (p. 8). |
| 出版: | Natick, Mass. : Navy Clothing and Textile Research Unit |
| 出版: | Atlanta, Ga. : [For sale by the Supt. of Docs., U. S. Gov't. Print. Off., Washington] |
| 附註: | "Produced by CDC Training Programs". Cover title. |
| 出版: | Washington, D.C. : National Aeronautics and Space Administration : [For sale by the Office of Technical Services, Dept. of Commerce] |
| 附註: | "November 1971."--Cover. Major NASA subject terms: Ejection, equations of motion, shells (structural forms), sounding rockets, aerodynamic forces, angular velocity, couples, nose cones. Includes bibliographical references (p. 21-22). The equations for the motion, forces, and couples generated by clamshells released from spinning sounding rockets in accordance with a roll-out ejection concept are presented. The application of these equations to a study of a system for the Javelin (i.e., Honest John-Nike-Nike-X248) rocket vehicle is discussed. The roll-out ejection concept advocated requires that each deploying clamshell be pivoted about an axis at its trailing edge located in the system sectioning plane. Clamshell despinning is a consequence of this deployment since the pivotal, i.e., roll-out, rate is in opposition to the rocket vehicle spin. The energy required by the deployment is derived largely from the rotational energy of the clamshell. Thus, the rocket vehicle will not be significantly despun by this kind of clamshell deployment. This ejection concept also permits a system design which makes it possible to limit clamshell angular motion to rotation about that one of its centroidal principal axes which is brought into parallelism with the rocket vehicle longitudinal axis. Also, by equalizing the moments of inertia about the other centroidal principal axes, the rollout motion can be decoupled from any extraneous angular motion about these axes. |
| 出版: | Washington : National Aeronautics and Space Administration |
| 附註: | N71-32415 Prepared by Lewis Research Center. Cover title. Includes bibliographical references (p. 45-46). In order to provide a relatively simple heat-transfer prediction along a nozzle, a differential (similar-solution) analysis for the turbulent boundary layer is developed. This analysis along with a new correlation for the turbulent Prandtl number gives good agreement of the predicted with the measured heat transfer in the throat and supersonic regiono f the nozzle. Also, the boundary-layer variables (heat transfer, etc. ) can be calculated at any arbitrary location in the throat or supersonic region of the nozzle in less than a half minute of computing time (Lewis DCS 7094-7044). |
| 出版: | Washington, D.C. : Springfield, Va. : National Aeronautics and Space Administration ; For sale by the National Technical Information Service |
| 附註: | Part of the information presented in this paper was originally presented in David A. Roberts' thesis (M.S.--George Washington University, 1971) under title: The application of gradient methods to differential games--Cf. p.[1]. "November 1971." "NASA TN D-6502." Cover title. Includes bibliographical references (p. 27). A technique for solving n-dimensional games is developed and applied to two pursuit-evasion games. The first is a two-dimensional game similar to the homicidal chauffeur but modified to resemble an airplane-helicopter engagement. The second is a five-dimensional game of two airplanes at constant altitude and with thrust and turning controls. The performance function to be optimized by the pursuer and evader was the distance between the evader and a given target point in front of the pursuer. The analytic solution to the first game reveals that both unique and nonunique solutions exist. A comparison between the gradient results and the analytic solution shows a dependence on the nominal controls in regions where nonunique solutions exist. In the unique solution region, the results from the two methods agree closely. The results for the five-dimensional two-airplane game are also shown to be dependent on the nominal controls selected and indicate that initial conditions are in a region of nonunique solutions. |
| 出版: | Miami : U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, Atlantic Oceanographic and Meteorological Laboratory |
| 出版: | Monterey, Calif. : Fleet Numerical Weather Central |