Ionosphere
Ionospheric dynamics and properties, structure of D and F regions, global wind circulation, and radio wave absorption
RADIO WAVE↗
SEARCH · Engineering Papers
Results for “Structural properties”
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.
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An electron microscopy and X-ray study of the recovery on annealing of cold-worked, dispersion-strengthened alloys.
X-ray diffraction-Fourier series analysis and electron microscopy analysis of annealing effects on structural properties of cold worked dispersion-strengthened alloys
ELECTRON MICROSCOPY↗
Development of improved structural adhesives Annual summary report, 27 Jul. 1966 - 30 Jul. 1967
Structure-property study of polyurethane, epoxy, polyisocyanurate, and polyoxazolidone adhesives
Follett, A. E.↗
Review of beryllium technology for spacecraft applications
Joining, working, and structural properties of beryllium and beryllium alloys for spacecraft applications
Moss, R. G.↗
Materials research Semiannual progress report, 1 Mar. - 31 Aug. 1968
Solid state reactions, structural properties, and characterizations of polymers and other materials
Source record↗
The structure of shear-dependent turbulence in a stably stratified medium.
Shear dependent turbulence in stably stratified medium, discussing structural properties, isotropic and axisymmetric forms and Reynolds stress
Justus, C. G.↗
Nature of the electrical transition in Ti sub 2 O sub 3.
Electrical, optical, magnetic and structural properties of titanium oxide, stressing transition difference with vanadium oxide
Honig, J. M.↗
Flame-resistant thin panels of glass fabric-polyimide resin laminates
With a cured polyimide resin content of less than about 20 percent by weight of the finished part, glass fabric laminates which have good structural properties and are self-extinguishing in a pure oxygen atmosphere can be prepared in the thickness range of 0.035 to 0.08 inch.
Kaumeyer, R. A.↗
On the invertibility of finite state machines
Structural properties of finite state machines invertible with delay L
Olson, R. R.↗
Concatenation of convolutional and block codes Final report
Comparison of concatenated and sequential decoding systems and convolutional code structural properties
Odenwalder, J. P.↗
Lunar bytownite from sample 12032,44
Optical, chemical and structural properties of lunar bytownite twin from U stage, microprobe and X ray measurements
Nord, G. L.↗
Thermal Skin fabrication technology
Advanced fabrication techniques applicable to Thermal Skin structures were investigated, including: (1) chemical machining; (2) braze bonding; (3) diffusion bonding; and (4) electron beam welding. Materials investigated were nickel and nickel alloys. Sample Thermal Skin panels were manufactured using the advanced fabrication techniques studied and were structurally tested. Results of the program included: (1) development of improved chemical machining processes for nickel and several nickel alloys; (2) identification of design geometry limits; (3) identification of diffusion bonding requirements; (4) development of a unique diffusion bonding tool; (5) identification of electron beam welding limits; and (6) identification of structural properties of Thermal Skin material.
Milam, T. B.↗
Stiffness and mass matrices for shells of revolution (SAMMSOR II)
Utilizing element properties, structural stiffness and mass matrices are generated for as many as twenty harmonics and stored on magnetic tape. Matrices generated constitute input data to be used by other stiffness of revolution programs. Variety of boundary and loading conditions can be employed without having to create new mass and stiffness matrices for each case.
Tillerson, J. R.↗
Bistatic-radar investigation
The purpose of the reported experiment was to determine the principal electromagnetic and structural properties of the lunar surface from the observation of command and service module (CSM) radio transmissions that were reflected from the lunar surface and received on earth. These transmissions emanate from the CSM communication systems at wavelengths of 13 cm (S-band) and 116 cm (very high frequency (VHF)). Lunar crustal properties such as dielectric constant, average slope and slope probability, density, small-scale surface roughness, and embedded rocks to a depth of 20 m may be determined. The results are proving to be most useful in understanding the processes that have produced and modified the crust and in distingushing between adjacent and subjacent geological units. The experimental observations are also of intrinsic interest in the study of electromagnetic scattering.
Howard, H. T.↗
A possible step in the origin of the genetic code.
It is suggested that the earliest coding polynucleotides contained a high proportion of alternating sequences of purines and pyrimidines, and that these sequences coded for polypeptides in which hydrophobic and hydrophylic amino acids alternated. Structural properties of such alternating polypeptides are discussed.
Orgel, L. E.↗
Thermally stable macromolecules.
Man-made polymers are compared with certain naturally occurring polymers which have long been used at elevated temperatures. The pyrolysis of model compounds is discussed together with aspects of thermogravimetric analysis, torsional braid analysis, and questions of chemical and radiation stability. Some structure-property relationships are examined, giving attention to asbestos, mica, graphite, and diamond. Questions of bond strengths are investigated along with the stability of ladder polymers and some fundamental concepts in the synthesis of aromatic and heteroaromatic polymers. The substances considered include aromatic single-strand polymers, heteroaromatic polymers, polymers obtained by addition polymerizations, and nonhydrogen-containing polymers. Future trends are also explored.
Pezdirtz, G. F.↗
Solid Propellant Grain Structural Integrity Analysis
The structural properties of solid propellant rocket grains were studied to determine the propellant resistance to stresses. Grain geometry, thermal properties, mechanical properties, and failure modes are discussed along with design criteria and recommended practices.
Source record↗
Connective stability of nonlinear matrix systems
Consideration of stability under structural perturbations of free dynamic systems described by the differential equation dx/dt = A(t,x)x, where the matrix A(t,x) has time-varying nonlinear elements. The concept of 'connective stability' is introduced to study the structural properties of competitive-cooperative nonlinear matrix systems. It is shown that stability reliability in such systems is high and that they remain stable despite time-varying (including 'on-off') interaction among individual agents present in the system. The results obtained can be used to study stability aspects of mathematical models arising in as diverse fields as economics, biology, arms races, and transistor circuits.
Siljak, D. D.↗