Flight comparison of several techniques for determining the minimum flying speed for a large, subsonic jet transport
Flight comparison of techniques for determining minimum flying speed for large, subsonic jet transport
Kier, D. A.↗
SEARCH · Search NASA
Results for “transport techniques”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Vapor phase growth of group 3, 4, and 5 compounds by HCl transport of elements
Technique has been devised for vapor-phase epitaxial growth of group 3, 4, and 5 binary, ternary, or quaternary compounds by HCl transport of the constituent elements or dopants. Technique uses all the constituents of the alloy system in their elemental form. Transport of these elements by an HCl + H2 carrier gas facilitates their transport as subchlorides.
Tyagi, R. C.↗
Vortex-state Complex Hall Conductivity of Superconducting YBa(sub 2)Cu(sub 3)O(sub 7-delta) Epitaxial Films at Radio Frequencies
The vortex-state complex Hall conductivity (o(sub xy)) of superconducting YBa(sub 2)Cu(sub 3)O(sub 7) epitaxial films is investigated from DC to radio frequencies (up to 7 x 10(sup 6) Hz), using a direct transport measurement technique.
superconductors transport properties↗
CRACK PROPAGATION PREDICTION AND CRACK STOPPER TECHNIQUES FOR STIFFENED CYLINDERS IN A SUPERSONIC TRANSPORT ENVIRONMENT
Crack propagation prediction and crack stopper techniques for stiffened cylinders in a supersonic transport environment
SUPERSONIC TRANSPORT↗
Transportation environmental measurement and recording system
Systems design of unattended system for automatic measurement and digital recording of critical transportation environmental parameters
ENVIRONMENT↗
Techniques for the determination of mass properties of earth-to-orbit transportation systems
One estimating technique involves trending whereby projections of overall mass properties of vehicles are determined with few inputs. The second technique involves trending of individual subsystems using equations of the form KXN to the nth power or KX. Some constants and exponentials are provided for sample subsystems. Mass properties are reported in a format recommended by mil spec - 38310.
Macconochie, I. O.↗
A model-based technique for predicting pilot opinion ratings for large commercial transports
A model-based technique for predicting pilot opinion ratings is described. Features of this procedure, which is based on the optimal-control model for pilot/vehicle systems, include (1) capability to treat 'unconventional' aircraft dynamics, (2) a relatively free-form pilot model, (3) a simple scalar metric for attentional workload, and (4) a straightforward manner of proceeding from descriptions of the flight task environment and requirements to a prediction of pilot opinion rating. The method is able to provide a good match to a set of pilot opinion ratings obtained in a manned simulation study of large commercial aircraft in landing approach.
Levison, W. H.↗
A model-based technique for predicting pilot opinion ratings for large commercial transports
A model-based technique for predicting pilot opinion ratings is described. Features of this procedure, which is based on the optimal-control model for pilot/vehicle systems, include (1) capability to treat "unconventional" aircraft dynamics, (2) a relatively free-form pilot model, (3) a simple scalar metric for attentional workload, and (4) a straightforward manner of proceeding from descriptions of the flight task environment and requirements to a prediction of pilot opinion rating. The method was able to provide a good match to a set of pilot opinion ratings obtained in a manned simulation study of large commercial aircraft in landing approach.
Levison, W. H.↗
Numerical modeling of pollutant transport using a Lagrangian marker particle technique
A derivation and code were developed for the three-dimensional mass transport equation, using a particle-in-cell solution technique, to solve coastal zone waste discharge problems where particles are a major component of the waste. Improvements in the particle movement techniques are suggested and typical examples illustrated. Preliminary model comparisons with analytic solutions for an instantaneous point release in a uniform flow show good results in resolving the waste motion. The findings to date indicate that this computational model will provide a useful technique to study the motion of sediment, dredged spoils, and other particulate waste commonly deposited in coastal waters.
Spaulding, M.↗
Process modelling for materials preparation experiments
The main goals of the research under this grant consist of the development of mathematical tools and measurement techniques for transport properties necessary for high fidelity modelling of crystal growth from the melt and solution. Of the tasks described in detail in the original proposal, two remain to be worked on: development of a spectral code for moving boundary problems, and development of an expedient diffusivity measurement technique for concentrated and supersaturated solutions. We have focused on developing a code to solve for interface shape, heat and species transport during directional solidification. The work involved the computation of heat, mass and momentum transfer during Bridgman-Stockbarger solidification of compound semiconductors. Domain decomposition techniques and preconditioning methods were used in conjunction with Chebyshev spectral methods to accelerate convergence while retaining the high-order spectral accuracy. During the report period we have further improved our experimental setup. These improvements include: temperature control of the measurement cell to 0.1 C between 10 and 60 C; enclosure of the optical measurement path outside the ZYGO interferometer in a metal housing that is temperature controlled to the same temperature setting as the measurement cell; simultaneous dispensing and partial removal of the lower concentration (lighter) solution above the higher concentration (heavier) solution through independently motor-driven syringes; three-fold increase in data resolution by orientation of the interferometer with respect to diffusion direction; and increase of the optical path length in the solution cell to 12 mm.
Rosenberger, Franz↗
An example of requirements for Advanced Subsonic Civil Transport (ASCT) flight control system using structured techniques
The requirements are presented for an Advanced Subsonic Civil Transport (ASCT) flight control system generated using structured techniques. The requirements definition starts from initially performing a mission analysis to identify the high level control system requirements and functions necessary to satisfy the mission flight. The result of the study is an example set of control system requirements partially represented using a derivative of Yourdon's structured techniques. Also provided is a research focus for studying structured design methodologies and in particular design-for-validation philosophies.
Mclees, Robert E.↗
Adaptive wall technology for three-dimensional models at high subsonic speeds and aerofoil testing through the speed of sound
Adaptive wall research at the University of Southampton has been directed towards the development of testing techniques for use in nonporous test sections where two flexible walls are profiled in single curvature. This paper highlights the recent advances that have been made in the testing of 2D airfoils through the speed of sound and the testing of 3D models at high subsonic speeds. Techniques have been developed to accommodate the variety of flow regimes encountered in near sonic airfoil tests. The experimental evidence to date suggests that the new techniques coupled with established procedures allow airfoil data, free from top and bottom wall interference, to be gathered from adaptive flexible walled test sections throughout the entire subsonic, transonic and supersonic speed ranges. Techniques applicable to the testing of 3D models have evolved primarily from experience gained by testing sidewall mounted half-wings. Emphasis has been placed upon models with planforms similar to those of current transport wings. Techniques for high subsonic speeds have now been developed to the point where the residual levels of interference are low.
Lewis, M. C.↗
CRACK PROPAGATION PREDICTION AND CRACKSTOPPER TECHNIQUES FOR STIFFENED CYLINDERS IN A SUPERSONIC TRANSPORT ENVIRONMENT FIRST QUARTERLY LITERATURE SUMMARY
Crack propagation prediction and prevention techniques for stiffened cylinders in supersonic transport environment
SUPERSONIC TRANSPORT↗
In-Situ Partial Pressure Measurements and Visual Observation during Crystal Growth of ZnSe by Seeded Physical Vapor Transport
An in-situ monitoring furnace was constructed with side windows to perform partial pressure measurements by optical absorption and visual observation of the growing crystal. A fused silica -rowth ampoule with a 4.5 cm long square tube between the source and the seed was prepared for the optical absorption measurements. A ZnSe crystal was grown by the seeded physical vapor transport (PVT) technique in the horizontal configuration. The growth temperature was 1120 C and the furnace translation rate was 3nmVday. Partial pressures of Se2, P(sub Se2), at three locations along the length of the growth ampoule were measured at 90 min intervals during the growth process. The measured P (sub Se2) were in the range of 2.0 to 6.5 x 10(exp -3) atm. The P(sub Se2) results indicated that the partial pressure profile was inconsistent with the results of the one-dimensional diffusion mass transport model and that the source composition shifted toward Se-rich during the run, i.e. the grown crystal was more Zn-rich than the source. The visual observation showed that the seed crystal first etched back, with greater thermal etching occurring along the edges of the seed crystal. Once the growth started, the crystal crew in a predominately contactless mode and facets were evident during growth. The crystal did not grow symmetrically which is believed to be due to the unintentional asymmetry of the radial thermal profile in the furnace.
Su, Ching-Hua↗
A new dynamical atmospheric ionizing radiation (AIR) model for epidemiological studies
A new Atmospheric Ionizing Radiation (AIR) model is currently being developed for use in radiation dose evaluation in epidemiological studies targeted to atmospheric flight personnel such as civilian airlines crewmembers. The model will allow computing values for biologically relevant parameters, e.g. dose equivalent and effective dose, for individual flights from 1945. Each flight is described by its actual three dimensional flight profile, i.e. geographic coordinates and altitudes varying with time. Solar modulated primary particles are filtered with a new analytical fully angular dependent geomagnetic cut off rigidity model, as a function of latitude, longitude, arrival direction, altitude and time. The particle transport results have been obtained with a technique based on the three-dimensional Monte Carlo transport code FLUKA, with a special procedure to deal with HZE particles. Particle fluxes are transformed into dose-related quantities and then integrated all along the flight path to obtain the overall flight dose. Preliminary validations of the particle transport technique using data from the AIR Project ER-2 flight campaign of measurements are encouraging. Future efforts will deal with modeling of the effects of the aircraft structure as well as inclusion of solar particle events. Published by Elsevier Ltd on behalf of COSPAR.
Aviation↗
Electron transport from a cosine law source
Cosine law source electron transport calculation technique
Wuller, C. E., Jr.↗
Parametric study of STOL short-haul transport engine cycles and operational techniques to minimize community noise impact
The effect of aircraft operational techniques in the terminal area on community noise impact of future short haul aircraft was investigated. Aircraft equipped with mechanical flap (MF) and aircraft with externally blown flap (EBF) were used to study the noise impact at four U.S. airports. The four airports were: (1) Hanscom Field (Boston), (2) Washington National (D.C.), (3) Midway (Chicago) and (4) Orange County (California). With the exception of Washington National (D.C.), the study showed that a reduction of approximately 40 percent in the number of people highly annoyed can be obtained by using the recommended operational techniques. The evaluation procedures and methodology developed in the study represent an advance in acoustical state-of-the-art and provide an effective and useful tool for determining aircraft noise impact on the airport community.
Source record↗
Growth of single crystals by vapor transport in zero-gravity environment, ground-based experiments
Mass and heat transfer phenomena associated with the growth of single crystals by chemical vapor transport reactions were investigated. In this technique, a gaseous transport agent reacts with the solid source material to form exclusively gaseous products. The gas phase species migrate from the source to the condensation zone of the closed reaction ampoule where the reverse reaction occurs with formation of single crystals. The necessary concentration gradient is achieved by means of a temperature gradient.
Wiedemeier, H.↗