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  • Other Sources  (2,410)
  • AERODYNAMICS  (1,256)
  • GENERAL  (1,154)
  • 1970-1974  (2,410)
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  • 1
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    In:  CASI
    Publication Date: 2006-01-11
    Description: It is stipulated that all of mankind owns the moon and that lunar exploration must be exclusively for peaceful purposes. In addition to the right to build stations on the moon, every country has the right to utilize the moon's natural resources. This includes: exploration, extraction, and processing of minerals and other natural resources, and their utilization and processing for local needs and possible also for export to earth.
    Keywords: GENERAL
    Type: Inhabited Space, Pt. 2 (NASA-TT-F-820); p 177-184
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  • 2
    Publication Date: 2011-08-16
    Description: An unsteady lifting-surface theory is developed for the calculation of the airload on a semi-infinite-span thin wing in a compressible flow due to interaction with an oblique gust. By using the solutions obtained for a two-dimensional wing, the problem is formulated so that the unknown is taken to be the difference between the airload on the semi-infinite wing and that on a two-dimensional wing under the same gust conditions. Since this airload difference is nonzero only near the wing tip, the control points need be distributed in the tip region only; this significantly simplifies the numerical procedure. Results are presented for a wing with rectangular tip. The implication for noise and unsteady loads due to blade-vortex interaction for helicopter rotors is discussed.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Dec. 197
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  • 3
    Publication Date: 2011-08-16
    Description: Limitations concerning the possibility to simulate all the significant flow and thermal phenomena occurring during the entry of a space vehicle into a planetary atmosphere make it necessary to rely on computational analyses to obtain the required data for the design of the spacecraft needed for the NASA missions planned for the next two decades. 'Benchmark' computer programs concerned with complete, detailed, and accurate computational solutions of entry problems are considered along with programs representing engineering approximations for cases in which the accuracy provided by the benchmark programs is not needed. The information obtainable by computational analysis has to be supplemented by actual flight experience in order to meet the goals of the NASA entry-technology program. The individual space missions planned for the coming years are examined together with the possibilities for obtaining the data needed to satisfy the entry requirements in each case.
    Keywords: AERODYNAMICS
    Type: Astronautics and Aeronautics; 12; Dec. 197
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  • 4
    Publication Date: 2011-08-16
    Description: The analysis of sound fields from arbitrary source distributions in terms of Legendre and spherical Hankel functions is well known. The purpose of this paper is to extend this classical method of analysis to environments such as jet flows where flow and flow gradients are inherently present. The wave-equation governing the radiation of sound in such an environment is derived. The steady state flow and flow gradients in the axial and transverse directions appear as coefficients in the terms of the wave-equation. A semi-numerical method is used to solve the wave-equation in terms of modified spherical harmonics yielding the phase velocities and the directivities of an infinite set of modes. The directivity of each mode is obtained in terms of modified Legendre functions by numerical integration. Some results of these directivity and phase-velocity calculations are presented for a limited number of frequency and flow parameters. Both convective and shear refraction are shown to be important.
    Keywords: AERODYNAMICS
    Type: Journal of Sound and Vibration; 36; Sept. 8
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  • 5
    Publication Date: 2011-08-16
    Description: A general equation governing aerodynamic sound generation in the presence of solid boundaries is derived. It is shown that all the theories in the literature appear as special cases of this general equation. Derived special equations for propeller and fan noise are likewise shown to be more general than the conventional equations in that they make allowance for variation in retarded time over the blade surfaces.
    Keywords: AERODYNAMICS
    Type: Acoustical Society of America; vol. 56
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  • 6
    Publication Date: 2011-08-16
    Description: A method for automatic numerical generation of a general curvilinear coordinate system with coordinate lines coincident with all boundaries of a general multi-connected region containing any number of arbitrarily shaped bodies is presented. With this procedure the numerical solution of a partial differential system may be done on a fixed rectangular field with a square mesh with no interpolation required regardless of the shape of the physical boundaries, regardless of the spacing of the curvilinear coordinate lines in the physical field, and regardless of the movement of the coordinate system. Numerical solutions for the lifting and nonlifting potential flow about Joukowski and Karman-Trefftz airfoils using this coordinate system generation show excellent comparison with the analytic solutions. The application to fields with multiple bodies is illustrated by a potential flow solution for multiple airfoils.
    Keywords: AERODYNAMICS
    Type: Journal of Computational Physics; 15; July 197
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  • 7
    Publication Date: 2011-08-16
    Description: The propagation of waves of acoustic frequencies in curved ducts of rectangular cross section is studied for the first four modes. The analysis makes use of Bessel functions of the order (n + 1/2) to construct curves of wavenumber in the duct versus imposed wavenumber and to determine the profile of vibrational velocities. A wide range of duct widths and unrestricted radii of curvature have been considered. The characteristics of motion in a bend are compared with propagation of waves in a straight duct, and important differences in the behavior of waves are noted.
    Keywords: AERODYNAMICS
    Type: Acoustical Society of America; vol. 56
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  • 8
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    Publication Date: 2011-08-16
    Description: A scanning laser Doppler velocimeter was used to measure the axial velocity defect in the cores of trailing vortices behind a lifting airfoil of rectangular planform. Data were obtained at several different angles of attack and downstream distances ranging from 30 to 1000 chord lengths. The test was designed to obtain continuous data from the near field into the far field while removing uncertainties associated with the interpretation of data obtained by the hydrogen bubble technique. The measured velocities of V sub x/U sub infinity are compared with those predicted. The agreement is remarkably good over the entire range of downstream distances, which supports the credibility of calculating axial velocities using the results of Moore and Saffman (1973).
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Aug. 197
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  • 9
    Publication Date: 2011-08-16
    Description: A backscatter laser Doppler velocimeter which simultaneously senses the axial and the tangential components of the velocity has been used to measure the velocity distributions in the near wake of a swept wing semispan transport model in a wind tunnel. The model configuration included nacelles, pylons, antishock bodies, and wing flaps which could be deflected 27 deg. Typical wake vortex velocity profiles are presented for the flaps-retracted and the flaps-deployed 27 deg configurations, respectively.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 11; June 197
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  • 10
    Publication Date: 2011-08-16
    Description: The Mariner Venus/Mercury '73 project kept within its originally established goals for schedule, performance, and cost. Underlying this development success was the availability of the Mariner technology. But meeting the goals demanded management determination, planning, and discipline to make optimum use of state-of-the-art technology. The present work points out management approaches and techniques that kept schedules and controlled costs, the intent being to stimulate thought about how to do the same with future spacecraft and payloads.
    Keywords: GENERAL
    Type: Astronautics and Aeronautics; 12; June 197
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  • 11
    Publication Date: 2011-08-16
    Description: A primary factor governing hypersonic flowfield characteristics of blunt vehicles entering planetary atmospheres is the normal shock density ratio. Hence, a means of duplicating or simulating the high density ratios experienced during planetary entry is needed. One facility having the capability of generating a range of hypersonic-hypervelocity flow conditions in arbitrary test gases is the expansion tube. Preliminary shock shape results obtained in the Langley 6-in. expansion tube at hypersonic conditions are presented. Normal shock density ratios from approximately 4 to 19 were generated using helium, air, and CO2 test gases at freestream velocities from 5 to 7 km/sec. Test models were a flat-faced cylinder and the Viking aeroshell.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Mar. 197
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  • 12
    Publication Date: 2011-08-16
    Description: Some results are described for a lifting rectangular wing centrally located on a circular-cylindrical body. This simple configuration has been utilized in order to assess the merits of a mapping technique for wing-body configurations. The procedure employed makes use of a coordinate transformation to simplify specification of the surface boundary condition in the computation of the flow about the wing. The method can be extended to incorporate wing sweep, finite length body of noncircular cross section, and arbitrary wing placement; however, these extensions involve a considerable increase in complexity of the problem.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 11; Apr. 197
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  • 13
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    Publication Date: 2011-08-16
    Description: A mathematical model of the vortex flow over a slender sharp-edged delta wing is proposed, and is shown to provide good agreement with the experiment. Although the technique requires experimental data in the form of the vortex core locations, it does account for the previously ignored mass entrainment of the vortex core.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Jan. 197
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  • 14
    Publication Date: 2011-08-16
    Description: Results are presented of a procedure for estimating stability and control parameters from flight data, by using maximum likelihood methods employing an interactive computer system, which was established at the NASA Langley Research Center. Problems encountered are discussed.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 49-76
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  • 15
    Publication Date: 2011-08-16
    Description: A maximum likelihood estimator for a linear system with state and observation noise is developed to determine stability and control derivatives from flight data obtained in the presence of turbulence. The formulation for the longitudinal short-period mode is presented briefly, including a special case that greatly simplifies the problem if the measurement noise on one signal is negligible. The effectiveness and accuracy of the technique are assessed by applying it first to simulated flight data, in which the true parameter values and state noise are known, then to actual flight data obtained in turbulence. The results are compared with data obtained in smooth air and with wind-tunnel data. The complete maximum likelihood estimator, which accounts for both state and observation noise, is shown to give the most accurate estimate of the stability and control derivatives from flight data obtained in turbulence. It is superior to the techniques that ignores state noise and to the simplified method that neglects the measurement noise on the angle-of-attack signal.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 77-114
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  • 16
    Publication Date: 2011-08-16
    Description: Two methods for extracting stability derivatives from flight data are compared. A modified Newton-Raphson quasilinearization minimization technique and a digital-analog (hybrid) matching technique were used to analyze the same data maneuvers obtained from two aircraft. About 70 maneuvers from an F-111E aircraft were analyzed over a Mach number range of 0.3 to 2.0 and an angle of attack range of 3 to 19 degrees. About 20 maneuvers were analyzed for the X-24A lifting body at Mach numbers of 0.5, 0.8, and 0.9, and an angle of attack range of 4 to 13 degrees. Stability derivatives were extracted from these maneuvers and the results from the two techniques, along with wind tunnel results, were compared.
    Keywords: AERODYNAMICS
    Type: NASA. Flight Res. Center Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 43-48
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  • 17
    Publication Date: 2011-08-16
    Description: Description of a correlation, derived from water tank measurements in the wake of wings towed under water, that makes it possible to predict the downstream distance behind an aircraft in flight where its trailing vortex will begin to decay. Comparisons of measured and predicted data are discussed.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 11; Nov. 197
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  • 18
    Publication Date: 2011-08-16
    Description: The artificial viscosity method of Kuwahara and Takami (1973) is used to calculate the roll-up of trailing vortices behind a number of practical aerodynamic configurations. Where possible, the results are compared for core location with available experimental data.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 11; Nov. 197
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  • 19
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    In:  Other Sources
    Publication Date: 2011-08-16
    Keywords: GENERAL
    Type: APL Bull. of the 20th Interagency Solid Propulsion Meeting, Vol. 4; p 427-437
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  • 20
    Publication Date: 2011-08-16
    Description: Electron density profiles which include the effect of an ablated sodium impurity were computed for the boundary layer on a blunt-nosed body re-entering the atmosphere at 7.62 km/sec. Profiles are computed from the nose to a distance of four diameters along the RAM C-payload. A finite-difference, laminar, nonequilibrium chemistry boundary-layer program was used. Comparison of theory with S-band diagnostic antenna results, electron concentration deduced from X- and C-band attenuation data, and Langmuir probe data at several different aft body locations show that agreement is good at high altitude. At the lower altitudes there is disagreement between theory and S-band antenna data where the apparent discrepancy is attributed to the three-body recombination rate constant used for deionization of sodium coupled with the effect of angle of attack.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; June 197
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  • 21
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    Publication Date: 2011-08-16
    Description: The methods of development, designation and application of the charts under multitopic conditions are considered.
    Keywords: GENERAL
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 15-20
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  • 22
    Publication Date: 2011-08-16
    Description: One of the basic conditions of high quality manufacture of instruments is the error free developed design documentation. A procedure is described for organizing the design check of the drawings.
    Keywords: GENERAL
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 21-24
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  • 23
    Publication Date: 2011-08-16
    Description: The basic principles of constructing the models and rules for their application in the development of PERT charts are discussed.
    Keywords: GENERAL
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 11-14
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  • 24
    Publication Date: 2011-08-16
    Description: The difficulties in obtaining exact calculation data for the labor input and estimated cost are noted. The method of calculating the labor cost of the design work using the provisional normative indexes with respect to individual forms of operations is proposed. Values of certain coefficients recommended for use in the practical calculations of the labor input for the development of new scientific equipment for space research are presented.
    Keywords: GENERAL
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 3-10
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  • 25
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    Publication Date: 2011-08-16
    Description: The Government-Industry Data Exchange Program (GIDEP) was originated in 1959 by the Army, Navy, and Air Force Ballistic Missile Agencies. Known at that time as IDEP--Interservice Data Exchange Program--its intent was to eliminate duplicate testing of parts and components by disseminating pertinent test data among Department of Defense contractors and various government agencies. In 1966 both the National Aeronautics and Space Administration and the Canadian Military Electronics Standards Agency (CAMESA) recognized the value of the data provided by the program and became participants. Today, GIDEP provides the interchange of specialized technical data to all the military services, participating government contractors and numerous government agencies such as the Atomic Energy Commission, Federal Aviation Administration, Defense Supply Agency, and the Small Business Administration.
    Keywords: GENERAL
    Type: NBS The Role of Cavitation in Mech. Failures; p 166-170
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  • 26
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    Publication Date: 2011-08-16
    Description: The growth of the field of system identification is discussed along with changes in methodology which have taken place in recent years. The similarity between pattern recognition and system identification is pointed out, involving the modelling in the latter and the feature selection problem in the former. It is stated that once a model is formulated, including the disturbances and measurement errors, the parameter finding can be formulated as a statistical estimation problem. The various techniques and their application are discussed.
    Keywords: AERODYNAMICS
    Type: NASA. Flight Res. Center Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 381-385
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  • 27
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    Publication Date: 2011-08-16
    Description: A state-of-the-arts review is given for the field of system identification. Progress in the field is traced from the early models of dynamic systems by Sir Isaac Newton up to the present day use of advanced techniques for numerous applications.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 375-379
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  • 28
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    Publication Date: 2011-08-16
    Description: The criterion that is proposed is an expected value of the mean square response error as an alternative to testing a model against new data. Modeling with respect to this new criterion does not change the estimate for a given model format from a maximum likelihood estimate or mean square response error estimate. The new criterion does, however, provide a means of comparing models with different formats and varying complexity. A numerical example is used to illustrate the application of the proposed criteria and the problem of searching for the best model. For all but the most trivial system identification problems, it is shown that a prohibitive number of combinations of terms of the model must be investigated to ensure the final model is best.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 291-313
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  • 29
    Publication Date: 2011-08-16
    Description: An error analysis program based on an output error estimation method was used to evaluate the effects of sensor and instrumentation errors on the estimation of aircraft stability and control derivatives. A Monte Carlo analysis was performed using simulated flight data for a high performance military aircraft, a large commercial transport, and a small general aviation aircraft for typical cruise flight conditions. The effects of varying the input sequence and combinations of the sensor and instrumentation errors were investigated. The results indicate that both the parameter accuracy and the corresponding measurement trajectory fit error can be significantly affected. Of the error sources considered, instrumentation lags and control measurement errors were found to be most significant.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 261-280
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  • 30
    Publication Date: 2011-08-16
    Description: The parameter identification scheme being used is a differential correction least squares procedure (Gauss-Newton method). The position, orientation, and derivatives of these quantities with respect to the parameters of interest (i.e., sensitivity coefficients) are determined by digital integration of the equations of motion and the parametric differential equations. The application of this technique to three vastly different sets of data is used to illustrate the versatility of the method and to indicate some of the problems that still remain.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 191-195
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  • 31
    Publication Date: 2011-08-16
    Keywords: GENERAL
    Type: AF Inst. of Technol. Proc. of the 10th Ann. Conf. on Manual Control; p 677-703
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  • 32
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    Publication Date: 2011-08-16
    Keywords: GENERAL
    Type: AF Inst. of Technol. Proc. of the 10th Ann. Conf. on Manual Control; p 477-501
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  • 33
    Publication Date: 2011-08-16
    Keywords: GENERAL
    Type: AF Inst. of Technol. Proc. of the 10th Ann. Conf. on Manual Control; p 439-465
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  • 34
    Publication Date: 2011-08-16
    Keywords: GENERAL
    Type: AF Inst. of Technol. Proc. of the 10th Ann. Conf. on Manual Control; p 1-38
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  • 35
    Publication Date: 2011-08-16
    Keywords: GENERAL
    Type: AF Inst. of Technol. Proc. of the 10th Ann. Conf. on Manual Control; p 397-426
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  • 36
    Publication Date: 2011-08-16
    Keywords: GENERAL
    Type: Shock and Vibration Inform. Center The Shock and Vibration Bull. No. 44, Part 3; p 1-5
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  • 37
    Publication Date: 2012-05-22
    Description: The aerodynamic effectiveness of various propulsive lift concepts to provide for the low speed performance and control required for short takeoff and landing aircraft is discussed. The importance of the interrelationship between the propulsion system and aerodynamic components of the aircraft is stressed. The relative effectiveness of different lift concepts was evaluated through static and wind tunnel tests of various aerodynamic models and propulsion components, simulations of aircraft, and in some cases, flight testing of research aircraft incorporating the concepts under study. Results of large scale tests of lift augmentation devices are presented. The results of flight tests of STOL research aircraft with augmented jet flaps and rotating cylinder flaps are presented to show the steeper approach flight paths at low forward speeds.
    Keywords: AERODYNAMICS
    Type: AGARD V/STOL Aerodyn.; 6 p
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  • 38
    Publication Date: 2011-08-16
    Description: A numerical generalized-capacity-matrix technique is developed for application to aerodynamic flow computations. This technique allows the very fast direct (noniterative) numerical elliptic solvers to be used in problems with arbitrary internal boundaries and with a wide class of boundary conditions, including numerical application of the Kutta condition on an airfoil without iteration. Accuracy, speed, and usefulness of the technique are demonstrated with linear problems for potential flows over airfoil shapes. The method's main advantages, however, can be exploited within iterative procedures for a variety of complex flow problems governed by systems of equations not necessarily elliptic or linear.
    Keywords: AERODYNAMICS
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  • 39
    Publication Date: 2011-08-16
    Description: A fast direct (noniterative) 'Cauchy-Riemann Solver' is developed for solving the finite-difference equations representing systems of first-order elliptic partial differential equations in the form of the nonhomogeneous Cauchy-Riemann equations. The method is second-order accurate and requires approximately the same computer time as a fast cyclic-reduction Poisson solver. The accuracy and efficiency of the direct solver are demonstrated in an application to solving an example problem in aerodynamics: subsonic inviscid flow over a biconvex airfoil. The analytical small-perturbation solution contains singularities, which are captured well by the computational technique. The algorithm is expected to be useful in nonlinear subsonic and transonic aerodynamics.
    Keywords: AERODYNAMICS
    Type: Journal of Computational Physics; 15; May 1974
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  • 40
    Publication Date: 2011-08-16
    Description: Some recent experience at Ames Research Center in the estimation of aerodynamic coefficients for the Lear-Jet and the Augmentor Wing Jet STOL Research Aircraft is reviewed. The coefficients estimated from flight data are compared with values based on large-scale wind-tunnel tests. The results obtained by the regression and quasilinearization identification techniques are also compared. The regression method generally provides the lower standard deviation in the coefficient estimates and provides the better fit to the wind-tunnel values. The addition of nonlinear terms in the aerodynamic equations decreases the difference between the estimated and measured time histories but also increases the standard deviation in the estimated coefficient values.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 125-148
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  • 41
    Publication Date: 2011-08-16
    Description: Discussion of the local heating effect on the lee-side control flaps of supersonic configurations due to the interaction between vortices and leeward control surfaces at an angle of attack. Considerations are given for an appropriate positioning of control flaps to alleviate such interactions and the resulting thermal effect. Tests are carried out on a sharp right circular cone with two types of flap configurations in a study of oil flow patterns about the cone at selected angles of attack. Splitting of flaps and moving them to positions away from the symmetry plane did reduce the heating but also reduced the average flap pressure and increased flow complexity.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 11; Mar. 197
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  • 42
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    Publication Date: 2011-08-16
    Description: A new static probe design is described in which the static holes are located much closer to the tip than in conventional probes. The new probe shows promise for use in some situations where conventional probes become highly inaccurate. An additional advantage of the new design is that, when used in static pressure survey rakes, the probes can be located much closer together than in conventional designs and still ensure that disturbances from neighboring probe tips do not affect the static readings.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Apr. 197
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  • 43
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    Publication Date: 2011-08-16
    Description: Presented data on vortex-induced heating in a cone-cylinder body at Mach 6 show that the most severe heating need not occur as a result of the interaction of the primary vortices with the lee surface, even though this interaction produces a large, well-defined featherline oil smear. It is pointed out that the severity of vortex-induced heating is extremely sensitive to Reynolds number and geometry and that there exists a 'threshold Reynolds number' below which vortex-induced heating decreases abruptly.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 11; Feb. 197
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  • 44
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    Publication Date: 2011-08-16
    Description: Description of a procedure for optimal selection of research experiments to be performed aboard the Space Shuttle. The procedure is designed to provide the study team with a credible approach to their task. The procedure is characterized as methodologically sound and based on assumptions which reasonably approximate the real conditions. The data-gathering techniques proposed are accepted by scientifically trained personnel.
    Keywords: GENERAL
    Type: IEEE Transactions on Engineering Management; EM-21; Feb. 197
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  • 45
    Publication Date: 2011-08-16
    Description: The changes in aerodynamic characteristics due to real-gas effects associated with high speed flight (characterized by large shock density ratios) are primarily the result of changes in surface pressures acting on the forebody. The surface pressures are affected by a change in shock density ratio (real-gas effects) in two ways. First, the level of pressure at the stagnation point relative to freestream dynamic pressure is changed, and second, the distribution of surface pressure relative to stagnation-point pressure is changed. The density-ratio effect on the stagnation point pressure level can be estimated by considering the flow of a perfect gas about a blunt body.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 11; Jan. 197
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  • 46
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    Publication Date: 2012-05-22
    Description: An analysis of the development and technological applications of V/STOL aircraft is presented. The use of V/STOL aircraft to overcome the limitations of conventional aircraft is discussed. The aspects of V/STOL aircraft which are considered are: (1) economic penalties of propulsive lift, (2) advantages of propulsive lift, (3) potential improvements in V/STOL aircraft, (4) the aerodynamics of V/STOL aircraft, and (5) proposals for additional research in V/STOL development.
    Keywords: AERODYNAMICS
    Type: AGARD V/STOL Aerodyn.; 13 p
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  • 47
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    In:  CASI
    Publication Date: 2016-06-07
    Description: The development of a three axis stabilized balloon platform capable of being operated in three modes of increasing accuracy is discussed. The system relies on angular motion sensing for primary feedback with linear accelerometers, magnetometers, and a star sensor for positional information. When under primary control the system will acquire and stabilize on any accessible part of the celestial sphere. A video verification system is included to provide pointing confirmation. Under improved accuracy control, the star sensor is used to lock onto a target star.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 284-293
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  • 48
    Publication Date: 2016-06-07
    Description: The establishment and functions of the AFCRL balloon operations facility are discussed. The types of research work conducted by the facility are defined. The facilities which support the balloon programs are described. The free balloon and tethered balloon capabilities are analyzed.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 160-164
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  • 49
    Publication Date: 2016-06-07
    Description: A configuration has been developed for a long-life balloon platform to carry pointing telescopes weighing as much as 80 pounds (36 kg) to point at selected celestial targets. A platform of this configuration weighs about 375 pounds (170 kg) gross and can be suspended from a high altitude super pressure balloon for a lifetime of several months. The balloon platform contains a solar array and storage batteries for electrical power, up and down link communications equipment, and navigational and attitude control systems for orienting the scientific instrument. A biaxial controller maintains the telescope attitude in response to look-angle data stored in an on-board computer memory which is updated periodically by ground command. Gimbal angles are computed by using location data derived by an on-board navigational receiver.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 136-144
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  • 50
    Publication Date: 2016-06-07
    Description: A system capable of pointing a balloon-borne telescope at selected celestial objects to an accuracy of approximately 10 arc minutes for an extended period (weeks to months) without reliance on telemetry is described. A unique combination of a sun/star tracker, an on-board computer, and a gyrocompass is utilized for navigation, source acquisition and tracking, and data compression and recording. The possibilities for intelligent activities by the computer are also discussed.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 71-80
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  • 51
    Publication Date: 2016-06-07
    Description: An overview of an experimental and analytical research program underway for studying the aeroelastic and dynamic characteristics of tilt-rotor VTOL aircraft is presented. Selected results from several investigations of scaled models in the transonic dynamics tunnel, as well as some results from a test of a flight-worthy proprotor in the full-scale wind tunnel are shown and discussed with a view toward delineating various aspects of dynamic behavior peculiar to proprotor aircraft. Included are such items as proprotor/pylon stability, whirl flutter, gust response, and blade flapping. Theoretical predictions are shown to be in agreement with the measured stability and response behavior.
    Keywords: AERODYNAMICS
    Type: Its Rotorcraft Dyn.; p 171-184
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  • 52
    Publication Date: 2016-06-07
    Description: A nine degrees-of-freedom theoretical model was developed for investigations of the dynamics of a proprotor operating in high inflow axial flight on a cantilever wing. The theory is described, and the results of the analysis are presented for two proprotor configurations: a gimballed, stiff-inplane rotor, and a hingeless, soft-inplane rotor. The influence of various elements of the theory are discussed, including the modeling used for the blade and wing aerodynamics, and the influence of the rotor lag degree of freedom. The results from full-scale tests of the two proprotors are presented and compared with the theoretical results.
    Keywords: AERODYNAMICS
    Type: Its Rotorcraft Dyn.; p 159-169
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  • 53
    Publication Date: 2019-06-28
    Description: A lifting airfoil theoretically designed for shockless supercritical flow utilizing a complex hodograph method has been evaluated in the Langley 8-foot transonic pressure tunnel at design and off-design conditions. The experimental results are presented and compared with those of an experimentally designed supercritical airfoil which were obtained in the same tunnel.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-3082 , L-9548 , NAS 1.15:X-3082
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  • 54
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    In:  CASI
    Publication Date: 2019-06-27
    Keywords: GENERAL
    Type: NASA-CR-150043 , SR-S-30
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  • 55
    Publication Date: 2019-06-27
    Description: Concepts from the theory of functionals are used to develop nonlinear formulations of the aerodynamic force and moment systems acting on bodies in large-amplitude, arbitrary motions. The analysis, which proceeds formally once the functional dependence of the aerodynamic reactions upon the motion variables is established, ensures the inclusion, within the resulting formulation, of pertinent aerodynamic terms that normally are excluded in the classical treatment. Applied to the large-amplitude, slowly varying, nonplanar motion of a body, the formulation suggests that the aerodynamic moment can be compounded of the moments acting on the body in four basic motions: steady angle of attack, pitch oscillations, either roll or yaw oscillations, and coning motion. Coning, where the nose of the body describes a circle around the velocity vector, characterizes the nonplanar nature of the general motion.
    Keywords: AERODYNAMICS
    Type: NASA-TR-R-421 , A-5057
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  • 56
    Publication Date: 2019-06-27
    Description: Two methods for determining the virtual origin of turbulent boundary layers in hypersonic flow are evaluated. The results of the analyses are restricted to wind-tunnel models having sharp-edged surfaces with zero or small pressure gradients. Virtual origin and skin friction estimates from these two methods are compared with values from a base method for which the virtual origin is calculated from the measured momentum thickness at a station downstream of boundary layer transition.
    Keywords: AERODYNAMICS
    Type: ASME PAPER 74-APM-V
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  • 57
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    In:  CASI
    Publication Date: 2019-06-27
    Description: A one man inflatable life raft is described. The raft has an inflatable tube perimetrically bounding the occupant receiving space with a flexible floor member. A zippered opening in the floor allows entry and facilitates the use of a constant diameter tube. An airtight fabric bulkhead divides the peripheral tube longitudinally into inflatable tube sections, where if either tube section were punctured, the bulkhead would move into the punctured section to substitute for the punctured wall portion and maintain the inflatable volume of the tube. The floor member is attached to the central portion of the tube wall so that either side of the raft can be the up side.
    Keywords: GENERAL
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  • 58
    facet.materialart.
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    In:  CASI
    Publication Date: 2019-06-27
    Description: A method is described of making rolling elements by forming low mass cores having either hollow centers or being of a low mass material. The low mass cores are plated and heat treated to provide hard surfaces on the rolling elements. After grinding to the proper diameter the rolling elements are assembled between races to form a hearing.
    Keywords: GENERAL
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  • 59
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    In:  CASI
    Publication Date: 2019-06-27
    Description: A circuit which maintains the inertial element of a gyroscope or accelerometer at a constant position by delivering pulses to a rebalancing motor is discussed. The circuit compensates for temperature changes by using a temperature sensor that varies the threshold of inertial element movement required to generate a rebalance pulse which reacts to changes in viscosity of the flotation fluid. The output of the temperature sensor also varies the output level of the current source to compensate for changes in the strength of the magnets of the rebalancing motor. The sensor also provides a small signal to the rebalance motor to provide a temperature dependent compensation for fixed drift or fixed bias.
    Keywords: GENERAL
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  • 60
    Publication Date: 2019-06-27
    Description: A general guide is presented for performing system safety analyses of hardware, software, operations and human elements of an aerospace program. The guide describes a progression of activities that can be effectively applied to identify hazards to personnel and equipment during all periods of system development. The general process of performing safety analyses is described; setting forth in a logical order the information and data requirements, the analytical steps, and the results. These analyses are the technical basis of a system safety program. Although the guidance established by this document cannot replace human experience and judgement, it does provide a methodical approach to the identification of hazards and evaluation of risks to the system.
    Keywords: GENERAL
    Type: NASA-TM-X-64799
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  • 61
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    In:  CASI
    Publication Date: 2019-06-27
    Description: A computer system is reported that uses adaptive voting to tolerate failures and operates in a fail-operational, fail-safe manner. Each of four computers is individually connected to one of four external input/output (I/O) busses which interface with external subsystems. Each computer is connected to receive input data and commands from the other three computers and to furnish output data commands to the other three computers. An adaptive control apparatus including a voter-comparator-switch (VCS) is provided for each computer to receive signals from each of the computers and permits adaptive voting among the computers to permit the fail-operational, fail-safe operation.
    Keywords: GENERAL
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  • 62
    Publication Date: 2019-06-27
    Description: A general overview is given of the National Space Science Data Center (NSSDC) Standard Information Retrieval System. A description, in general terms, the information system that contains the data files and the software system that processes and manipulates the files maintained at the Data Center. Emphasis is placed on providing users with an overview of the capabilities and uses of the NSSDC Standard Information Retrieval System (SIRS). Examples given are taken from the files at the Data Center. Detailed information about NSSDC data files is documented in a set of File Users Guides, with one user's guide prepared for each file processed by SIRS. Detailed information about SIRS is presented in the SIRS Users Guide.
    Keywords: GENERAL
    Type: NASA-TM-X-69903 , NSSDC-74-09
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  • 63
    Publication Date: 2019-06-27
    Description: The role of nuclear fission reactors in becoming an important power source in the world is discussed. The supply of fissile nuclear fuel will be severely depleted by the year 2000. With breeder reactors the world supply of uranium could last thousands of years. However, breeder reactors have problems of a large radioactive inventory and an accident potential which could present an unacceptable hazard. Although breeder reactors afford a possible solution to the energy shortage, their ultimate role will depend on demonstrated safety and acceptable risks and environmental effects. Fusion power would also be a long range, essentially permanent, solution to the world's energy problem. Fusion appears to compare favorably with breeders in safety and environmental effects. Research comparing a controlled fusion reactor with the breeder reactor in solving our long range energy needs is discussed.
    Keywords: GENERAL
    Type: NASA-CR-138117
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  • 64
    Publication Date: 2019-06-27
    Description: Five classes of publications are included in this bibliography: (1) Technical Reports in which the information is complete for a specific accomplishment and is intended for a wide audience. (2) Articles from the bimonthly Deep Space Network Progress Report. Each volume's collection of articles presents a periodical survey of current accomplishments by the Deep Space Network. (3) Technical Memorandums, in which the information is complete for a specific accomplishment but is intended for a limited audience to satisfy unique requirements. (4) Articles from the JPL Quarterly Technical Review. Each article summarizes a recent important development, interim or final results, or an advancement in the state of the art in a scientific or engineering endeavor, This publication has been discontinued, and the issues indexed in this bibliography are the last to be published. (5) Articles published in the open literature. The publications are indexed by: (1) author, (2) subject, and (3) publication type and number. A descriptive entry appears under the name of each author of each publication; an abstract is included with the entry for the primary (first-listed) author.
    Keywords: GENERAL
    Type: NASA-CR-138171 , JPL-BIBL-39-15
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  • 65
    Publication Date: 2019-06-27
    Description: The results of an experimental investigation to increase the stable airflow operating range of a supersonic mixed-compression inlet are presented. Two forward-slanted slot stability-bypass entrance configurations were tested. In terms of diffuser-exit corrected airflow, a large inlet stable airflow range of 18.5 percent was obtained with the superior configuration if a constant pressure was maintained in the bypass plenum. Limited unstart angle-of-attack data are presented.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-2973 , E-7706
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  • 66
    Publication Date: 2019-06-27
    Description: An experimental investigation was made to determine the effects of screen-induced total-pressure distortions on two J85-GE-13 turbojet engines. Results were compared to those from a previous program run with a third engine. All compressors were found to be sensitive to a critical angle of circumferential distortion equal to 60 deg., and they all adhered closely to the parallel compressor model. The sensitivity of compressor exit pressure to virtually any type of distortion pattern can be determined by defining stall lines for undistorted, hub radial distorted, and tip radial distorted inflows. The effect of multiple sectors of circumferential distortion is defined.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-3017 , E-7792
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  • 67
    Publication Date: 2019-06-27
    Description: The documents available from the National Space Science Data Center and the World Data Center A for Rockets and Satellites are described. The availability, costs, ordering procedures for documents presently available, and the procedures for obtaining future documents are given.
    Keywords: GENERAL
    Type: NASA-TM-X-69904 , NSSDC/WDC-A-R/S-74-10
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  • 68
    Publication Date: 2019-06-27
    Description: Air pollution resulting from the use of fossil fuels is discussed. Phenomena relating to the emission of CO2 such as the greenhouse effect and multiplier effect are explored. Particulate release is also discussed. The following recommendations are made for the elimination of fossil fuel combustion products in the United States: development of nuclear breeder reactors, use of solar energy systems, exploration of energy alternatives such as geothermal and fusion, and the substitution of coal for gas and oil use.
    Keywords: GENERAL
    Type: NASA-CR-138183
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  • 69
    Publication Date: 2019-06-27
    Description: The conversion of fossil-fired power plants now burning oil or gas to burn coal is discussed along with the relaxation of air quality standards and the development of coal gasification processes to insure a continued supply of gas from coal. The location of oil fields, refining areas, natural gas fields, and pipelines in the U.S. is shown. The technologies of modern fossil-fired boilers and gas turbines are defined along with the new technologies of fluid-bed boilers and MHD generators.
    Keywords: GENERAL
    Type: NASA-CR-138188
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  • 70
    Publication Date: 2019-06-27
    Description: This publication represents a relisting of the Skylab-2, PTD Handheld Photography Catalog. The purpose of this publication is to provide imagery researchers a supplement to the PTD Catalog by alphabetically sorting together all similar major and minor features. Some cross-referencing of feature names was accomplished where the authors deemed necessary; however, no attempt was made to exhaust all possible means of cross-referencing. An example of the cross-referencing which was done: Kuril Islands may be found under the major feature column and also as a minor feature of Islands.
    Keywords: GENERAL
    Type: NASA-CR-134245 , LEC-2059
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  • 71
    Publication Date: 2019-06-27
    Description: A combined quadrupole-dipole model has been developed for the noise generated by inlet flow distortion in a subsonic fan. A formula is derived for the total upstream-radiated acoustic power in each tone as a function of the design parameters of the fan and the properties of the inlet flow distortion. Numerical results are obtained for values of the parameters corresponding to various quiet fans. The analysis is compared with noise measurements taken on a 51-cm (20-in.) diameter research fan as well as with those taken on a number of full-scale fan stages. Fairly good agreement was obtained. It should therefore be possible to use this model to study the noise-reduction potential of the various fan design parameters.
    Keywords: AERODYNAMICS
    Type: NASA-TN-D-7676 , E-7881
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  • 72
    Publication Date: 2019-06-27
    Description: An investigation was conducted in a low-turbulence pressure tunnel to determine the two-dimensional lift and pitching-moment characteristics of an NACA 6716 and an NACA 4416 airfoil with 35-percent-chord single-slotted flaps. Both models were tested with flaps deflected from 0 deg to 45 deg, at angles of attack from minus 6 deg to several degrees past stall, at Reynolds numbers from 3.0 million to 13.8 million, and primarily at a Mach number of 0.23. Tests were also made to determine the effect of several slot entry shapes on performance.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-2623 , L-8410
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  • 73
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    In:  CASI
    Publication Date: 2019-06-27
    Description: A target for dispensing high energy protons or neutrons or ionized atoms or ionized molecules is provided which comprises a container for the target gas, which is at atmospheric or higher pressure. The container material can release the target gas in the spot where the container is heated above a predetermined temperature by the impact of an ion beam where protons or neutrons are desired, or by electrons where ionized atoms or molecules are desired. On the outside of the container, except for the region where the beam is to impact, there is deposited a layer of a metal which is imperious to gaseous diffusion. A further protective coating of a material is placed over the layer of metal, except at the region of the ion impact area in order to adsorb any unreacted gas in the vacuum in which the target is placed, to thereby prevent reduction of the high vacuum, as well as contamination of the interior of the vacuum chamber.
    Keywords: GENERAL
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  • 74
    Publication Date: 2019-06-27
    Description: An optical system monitors the angular position of a rotating scanning mirror to indicate the effective start and end of each scan. At a certain angular position, a ray of energy transmitted to the mirror is reflected a plurality of times between the reflectors associated with the optical system and the line on the mirror parallel to the axis, and then to a detector to sense that angular position. A single optical system may be arranged to sense a plurality of different angular positions for each revolution of the mirror.
    Keywords: GENERAL
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  • 75
    Publication Date: 2019-06-27
    Description: A contoured boattail nozzle typical of those used on a twin-engine fighter was tested on an underwing nacelle mounted on an F-106B aircraft. The gas generator was a J85-GE-13 turbojet engine. The effects of Reynolds number, Mach number, and angle of attack on boattail drag and boattail pressure profiles were investigated. Increasing Reynolds number caused a slight reduction in boattail drag at both Mach 0.7 and 0.9. The nozzle had relatively low boattail drag even though the flow was separated over a large portion of the boattail.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-3053 , E-7818
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  • 76
    Publication Date: 2019-06-27
    Description: A description and analysis of selected State and Federal laws relating to land use inventories, monitoring, and evaluation is presented. Legal requirements and information systems for land use in the following states are reviewed: Colorado, Delaware, Florida, Hawaii, Indiana, Kansas, Maine, Mississippi, Missouri, Oklahoma, Pennsylvania, Tennessee, Utah, Vermont, and West Virginia.
    Keywords: GENERAL
    Type: NASA-CR-137332
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  • 77
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    In:  CASI
    Publication Date: 2019-06-27
    Description: The aerodynamic interaction between the wing and an inviscid jet with Mach number nonuniformity is formulated by using a two-vortex-sheet model for the jet. One of the vortex sheets accounts for the induced jet flow and the other the induced outer flow. No additional source distribution is needed for the jet at an angle of attack. The above problem is solved by satisfying the jet and wing tangency and the jet pressure-continuity conditions and using a quasi vortex lattice method for computing the induced flow field. The latter method is derived through theoretical consideration by properly accounting for singularities present in the equations and possesses the same simplicity and generality as the conventional vortex lattice method but has a better rate of numerical convergence. The resulting system of algebraic equations is solved by Purcell's vector method. The numerical formulation is first applied to the wing-slipstream interaction problem. Results for one centered-jet configuration are compared with those predicted by some existing theories.
    Keywords: AERODYNAMICS
    Type: NASA-CR-138140 , CRINC-FRL-74-001
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  • 78
    Publication Date: 2019-06-27
    Description: The effects of active controls on the suppression of flutter and gust alleviation of two different types of subsonic aircraft (the Arava, twin turboprop STOL transport, and the Westwind twin-jet business transport) are investigated. The active controls are introduced in pairs which include, in any chosen wing strip, a leading-edge (LE) control and a trailing-edge (TE) control. Each control surface is allowed to be driven by a combined linear-rotational sensor system, located on the activated strip. The control law, which translates the sensor signals into control surface rotations, is based on the concept of aerodynamic energy. The results indicate the extreme effectiveness of the active systems in controlling flutter. A single system spanning 10% of the wing semispan made the Arava flutter-free, and a similar active system, for the Westwind aircraft, yielded a reduction of 75% in the maximum bending moment of the wing and a reduction of 90% in the acceleration of the cg of the aircraft. Results for simultaneous activation of several LE - TE systems are presented. Further work needed to bring the investigation to completion is also discussed.
    Keywords: AERODYNAMICS
    Type: NASA-CR-138658 , TAE-198
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  • 79
    Publication Date: 2019-06-27
    Description: An approximate solution is reported for the unsteady aerodynamic response of an infinite swept wing encountering a vertical oblique gust in a compressible stream. The approximate expressions are of closed form and do not require excessive computer storage or computation time, and further, they are in good agreement with the results of exact theory. This analysis is used to predict the unsteady aerodynamic response of a helicopter rotor blade encountering the trailing vortex from a previous blade. Significant effects of three dimensionality and compressibility are evident in the results obtained. In addition, an approximate solution for the unsteady aerodynamic forces associated with the pitching or plunging motion of a two dimensional airfoil in a subsonic stream is presented. The mathematical form of this solution approaches the incompressible solution as the Mach number vanishes, the linear transonic solution as the Mach number approaches one, and the solution predicted by piston theory as the reduced frequency becomes large.
    Keywords: AERODYNAMICS
    Type: NASA-CR-2395
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  • 80
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    In:  CASI
    Publication Date: 2019-06-27
    Description: This report presents the derivation, description, and operating instructions for a computer program (TEKVAL) which measures the economic value of advanced technology features applied to long range commercial passenger aircraft. The program consists of three modules; and airplane sizing routine, a direct operating cost routine, and an airline return-on-investment routine. These modules are linked such that they may be operated sequentially or individually, with one routine generating the input for the next or with the option of externally specifying the input for either of the economic routines. A very simple airplane sizing technique was previously developed, based on the Brequet range equation. For this program, that sizing technique has been greatly expanded and combined with the formerly separate DOC and ROI programs to produce TEKVAL.
    Keywords: GENERAL
    Type: NASA-CR-132382
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  • 81
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    In:  CASI
    Publication Date: 2019-06-27
    Description: A shutter element is described which is formed by a loop of an electrically conductive ribbon disposed adjacent to the end of a passageway to be shuttered. The shuttered end of the passageway is cut at an acute angle. The two leg portions of the ribbon loop are closely spaced to each other and disposed in a plane parallel to the axis of the passageway. A pulse of high current is switched through the loop to cause the current flowing in opposite directions through adjacent leg portions of the ribbon. This produces a magnetically induced pressure on one of the legs of the ribbon forcing the leg over the end of the passageway in gas tight sealing engagement, and thereby blocking passageway.
    Keywords: GENERAL
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  • 82
    Publication Date: 2019-06-27
    Description: Three sting-mounted winged-body models with tunnel blockages of 0.1, 1.0, and 2.0 percent were tested in the Lewis Research Center's 8- by 6- Foot Supersonic Wind Tunnel. Fuselage pressures were obtained over a Mach number range of 0.6 to 1.0 at angles of attack from 0 deg to 4 deg. Two other types of model support were investigated, which included simulated wing-tip and fuselage support-strut mountings. The effects of tunnel porosity and sidewall geometry were also investigated. Model blockage effects were small up to M sub 0 = 0.95. At higher speeds the major blockage effect observed was a displacement of the local transonic terminal shocks on the model. The effects of the wing-tip type of model support were small up to M sub 0 = 0.95, but disturbances were observed on the fuselage at higher speeds. Changes in local tunnel porosity were effective in reducing the disturbances up to M sub 0 = 0.975, but a change in sidewall geometry was not.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-3011 , E-7596
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  • 83
    Publication Date: 2019-06-27
    Description: An experimental program was carried out in the NASA-Langley 4 ft x 4 ft supersonic pressure tunnel to investigate the validity of the heat-field concept for sonic boom alleviation. The concept involves heating the flow about a supersonic aircraft in such a manner as to obtain an increase in effective aircraft length and yield an effective aircraft shape that will result in a shock-free pressure signature on the ground. First, a basic body-of-revolution representing an SST configuration with its lift equivalence in volume was tested to provide a baseline pressure signature. Second, a model having a 5/2-power area distribution which, according to theory, should yield a linear pressure rise with no front shock wave was tested. Third, the concept of providing the 5/2-power area distribution by using an off-axis slender fin below the basic body was investigated. Then a substantial portion (approximately 40 percent) of the solid fin was replaced by a heat field generated by passing heated nitrogen through the rear of the fin.
    Keywords: AERODYNAMICS
    Type: NASA-CR-2381 , ATR-74(7218)-1
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  • 84
    facet.materialart.
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    In:  CASI
    Publication Date: 2019-06-27
    Description: A heat transfer device is characterized by an hermetically sealed tubular housing including a tubular shell terminating in spaced end plates, and a tubular mesh wick concentrically arranged and operatively supported within said housing. The invention provides an improved wicking restraint formed as an elongated and radially expanded tubular helix concentrically related to the wick and adapted to be axially foreshortened and radially expanded into engagement with the wick in response to an axially applied compressive load. The wick is continuously supported in a contiguous relationship with the internal surfaces of the shell.
    Keywords: GENERAL
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  • 85
    Publication Date: 2019-06-27
    Description: A gasket or seal resistant to ionizing radiation and liquid hydrogen temperatures is made up of a laminated polyquinoxaline resin-fiberglass cloth body portion and a molded polyquinoxaline encapsulating film. The laminated body is prepared by stacking thin sheets of the resin alternately with fiberglass cloth and heating the assembly under pressure with the temperature, pressure and resin film thickness being controlled so that only partial impregnation of the fiberglass cloth is produced. The encapsulating resin film is preheated at about 300 f and applied to the laminate body by molding at a temperature of about 625 F. The molded gasket is then deflashed and post-cured by heating at 675 to 700 F.
    Keywords: GENERAL
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  • 86
    Publication Date: 2019-06-27
    Description: An infrared radiation detector including a cadmium sulfide platelet having a cathode formed on one of its ends and an anode formed on its other end is presented. The platelet is suitably doped such that stationary high-field domains are formed adjacent the cathode when based in the negative differential conductivity region. A negative potential is applied to the cathode such that a high-field domain is formed adjacent to the cathode. A potential measuring probe is located between the cathode and the anode at the edge of the high-field domain and means are provided for measuring the potential at the probe whereby this measurement is indicative of the infrared radiation striking the platelet.
    Keywords: GENERAL
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  • 87
    Publication Date: 2019-06-27
    Description: Apparatus for remote handling of materials are described. A closed housing is provided with first and second containers and first and second reservoirs for holding materials to be mixed. The materials are transferable from the reservoirs to the first container where they are mixed. The mixed materials are then conveyed from the first container to the second container preferably by dumping the mixed materials into a funnel positioned over the second container. The second container is then moved to a second position for analysis of the mixed materials. For example, the materials may be ignited and the flame analyzed. Access, such as a sight port, is provided in the housing at the analysis position. The device provides a simple and inexpensive apparatus for safely mixing a pyrophoric material and an oxidizer which together form a thermite type mixture that burns to produce a large quantity of heat and light.
    Keywords: GENERAL
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  • 88
    Publication Date: 2019-06-27
    Description: A failure detector which detects the failure of a dc to ac inverter is disclosed. The inverter under failureless conditions is characterized by a known linear relationship of its input and output voltages and by a known linear relationship of its input and output currents. The detector includes circuitry which is responsive to the detector's input and output voltages and which provides a failure-indicating signal only when the monitored output voltage is less by a selected factor, than the expected output voltage for the monitored input voltage, based on the known voltages' relationship. Similarly, the detector includes circuitry which is responsive to the input and output currents and provides a failure-indicating signal only when the input current exceeds by a selected factor the expected input current for the monitored output current based on the known currents' relationship.
    Keywords: GENERAL
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  • 89
    Publication Date: 2019-06-27
    Description: Development of a method of estimating deviation angles by analytical procedures was begun. Solutions for inviscid, irrotational flow in the blade-to-blade plane were obtained with a finite-difference calculation method. Deviation angles for a plane cascade with a rounded trailing edge were estimated by using the inviscid-flow solutions and three trailing-edge hypotheses. The estimated deviation angles were compared with existing experimental data over a range of incidence angles at inlet flow angles of 30 deg and 60 deg. The results indicate that deviation angles can be estimated accurately (within 1 deg) by using one of the three trailing-edge hypotheses, but only when pressure losses are low. A new trailing-edge hypotheses is presented which is suitable (for the cascade considered) for both low- and high-loss operating points.
    Keywords: AERODYNAMICS
    Type: NASA-TN-D-7549 , E-7453
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  • 90
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-06-27
    Description: The concept of a 'system' is defined, and the 'systems approach' is discussed. Four contemporary examples of the systems approach are presented: an operations research project, the planning-programming-budgeting system, an information processing system, and aerospace programs.
    Keywords: GENERAL
    Type: NASA-CR-136833 , JPL-TM-33-667
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  • 91
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-06-27
    Description: An illustrative embodiment of the invention includes apparatus which simultaneously produces both direct delta modulation and pulse code modulation. An input signal, after amplification, is supplied to a window comparator which supplies a polarity control signal to gate the output of a clock to the appropriate input of a binary up-down counter. The control signals provide direct delta modulation while the up-down counter output provides pulse code modulation.
    Keywords: GENERAL
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  • 92
    Publication Date: 2019-06-27
    Description: A description of and users manual are presented for a U.S.A. FORTRAN 4 computer program which evaluates spanwise and chordwise loading distributions, lift coefficient, pitching moment coefficient, and other stability derivatives for thin wings in linearized, steady, subsonic flow. The program is based on a kernel function method lifting surface theory and is applicable to a large class of planforms including asymmetrical ones and ones with mixed straight and curved edges.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-62326
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  • 93
    Publication Date: 2019-06-27
    Description: Trailing-edge slot configurations were investigated in a two-dimensional cascade of turbine stator blades. The trailing-edge slots were incorporated into blades with round trailing edges. The five blade configurations investigated included blades with two different trailing-edge thicknesses and four different slot widths. The results of the investigation showed that there was, in general, a significant increase in primary-air efficiency due to the coolant flow, the increase varying with slot configuration. For the five configurations tested, the average percent change in primary-air efficiency per percent coolant flow varied almost linearly from zero to about 1.4 percent over a range of coolant- to primary-air exit-velocity ratios between 0 and 1.2. However, for different configurations there was considerable deviation from the average values in the lower range of exit velocity ratios.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-3000 , E-7743
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  • 94
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-06-27
    Description: Solid state welding a butt joint by fusion welding the peripheral surfaces to form a seal is described along with, autogenetically cleaning the faying or mating surfaces of the joint by heating the abutting surfaces to 1,200 C and heating to the diffusion welding temperature in air.
    Keywords: GENERAL
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  • 95
    Publication Date: 2019-06-27
    Description: A numerical solution is presented for the incompressible flow over thin planar and axisymmetric profiles at an angle of attack of 0 degrees. The method uses a finite-difference field solution to the governing equation with a Gauss-Seidel successive overrelaxation scheme. However, the use of a simple Cartesian grid system restricts this method to slender profiles. Results are presented for a cambered airfoil, airfoil in wall effect (two-dimensional flowthrough inlet), body of revolution, and flowthrough nacelle. A computer program is presented which can be used for any of the previously mentioned cases with simple input changes. Results for compressible flow are available with the use of the appropriate two-dimensional or axisymmetric compressibility corrections. Computational time for a typical field calculation of 3000 grid points and 200 cycles through the field is less than 1 minute with less than 50,000 octal storage on the Control Data Corporation 6600 computing system.
    Keywords: AERODYNAMICS
    Type: NASA-TN-D-7410 , L-8904
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  • 96
    Publication Date: 2019-06-27
    Description: An analytical procedure based on the Navier-Stokes equations was developed for analyzing and representing properties of unsteady viscous flow around oscillating obstacles. A variational formulation of the vorticity transport equation was discretized in finite element form and integrated numerically. At each time step of the numerical integration, the velocity field around the obstacle was determined for the instantaneous vorticity distribution from the finite element solution of Poisson's equation. The time-dependent boundary conditions around the oscillating obstacle were introduced as external constraints, using the Lagrangian Multiplier Technique, at each time step of the numerical integration. The procedure was then applied for determining pressures around obstacles oscillating in unsteady flow. The obtained results for a cylinder and an airfoil were illustrated in the form of streamlines and vorticity and pressure distributions.
    Keywords: AERODYNAMICS
    Type: NASA-CR-2368
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  • 97
    Publication Date: 2019-06-27
    Description: A description of and user's manual are presented for one of a group of FORTRAN programs which, together, can be used for the analysis and design of wings in steady, subsonic flow according to a kernel function method lifting surface theory. This particular program is the one which solves the sets of simultaneous, linear, algebraic equations arising from the thin wing analysis. This program has the capability of striking out rows and columns of the aerodynamic influence matrix and rows of the associated boundary condition vectors (right hand sides). This capability significantly enhances the effectiveness of the kernel function method of lifting surface theory because studies of the convergence of solutions with the number of control points can be done with the calculation of only a single influence matrix.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-62325
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  • 98
    Publication Date: 2019-06-27
    Description: A solid, half-scale model of a 50.8-cm (20-in) research turbine designed for a high temperature core engine application was investigated over a range of speeds and pressure ratios. The results of this test are presented. The effect of rotor blade twist was also investigated. At the design equivalent speed and specific work output, the total efficiency of the turbine with untwisted rotor blades was 87.1 percent; at the same pressure ratio the efficiency of the turbine with twisted rotor blades was 88.0 percent.
    Keywords: AERODYNAMICS
    Type: NASA-TN-D-7557 , E-7592
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  • 99
    Publication Date: 2019-06-27
    Description: A pair feeding method and apparatus are provided for experimental animals wherein the amount of food consumed is immediately delivered to a normal or control animal so that there is a qualitative, quantitative and chronological correctness in the pair feeding of the two animals. This feeding mechanism delivers precisely measured amounts of food to a feeder. Circuitry is provided between master and slave feeders so that there is virtually no chance of a malfunction of the feeding apparatus, causing erratic results. Recording equipment is also provided so that an hourly record is kept of food delivery.
    Keywords: GENERAL
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  • 100
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-06-27
    Description: A dual measurement ablation sensor for measuring both char-interface and surface recession at a point in an ablating material is described. The sensor permits measurement of the thickness of the char layer. Char-interface recession is indicated by a drop in the resistance to a current passed through the ablation material. Surface recession is indicated by the closing of an electrical circuit when melting causes the release of a spring switch.
    Keywords: GENERAL
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