True polarization curves for Beta Lyrae.
Beta Lyrae intrinsic polarization amount and phase dependence in visual, blue and UV light observed, analyzing polarization curves
ECLIPSING BINARY STAR↗
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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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The polarization curve and the absolute diameter of Vesta
Photoelectric polarization curve, reflectivity and absolute diameter of Vesta, comparing with Lyot curve
Veverka, J.↗
Analytical methods for computing the polar curves of airplanes
This report presents a method of calculating polar curves which is at least as precise as graphical methods, but it more rapid. Knowing the wind tunnel test of a wing and the performances of an airplane of the same profile, it is easy to verify the characteristic coefficients and, at the same time, the methods determining induced resistances.
LE SUEUR↗
Observations of structure in the interstellar polarization curve Preliminary results
We have measured the wavelength dependence of the interstellar polarization curve with higher wavelength resolution than has generally been used before. Our data show structure which has been previously unknown, and which may have important implications with respect to the composition of the interstellar grains. It is similar in general form to structure predicted on the basis of a theoretical model designed by us to give a detailed match to the extinction structure.
Mavko, G. E.↗
Asteroid reflectivities from polarization curves - Calibration of the 'slope-albedo' relationship.
The relationship between h, the slope of the positive branch of a polarization curve, and A, the normal reflectance of the surface, has been calibrated using a wide range of published data. It is determined that asteroid albedos can be inferred meaningfully by this method without prior knowledge of the detailed mineralogical composition of asteroid surfaces.
Veverka, J.↗
Interpretation of the brightness and polarization curves of the moon
Theoretical models for lunar brightness at small phase angles and polarization of moonlight
POLARIZATION↗
New Method of Determining the Polar Curve of an Airplane in Flight
A fundamental defect of existing methods for the determination of the polar of an airplane in flight is the impossibility of obtaining the thrust or the resistance of the propeller for any type airplane with any type engine. The new method is based on the premise that for zero propeller thrust the mean angle of attack of the blade is approximately the same for all propellers if this angle is reckoned from the aerodynamic chord of the profile section. This angle was determined from flight tests. Knowing the mean angle of the blade setting the angle of attack of the propeller blade at zero thrust can be found and the propeller speed in gliding obtained. The experimental check of the new method carried out on several airplanes gave positive results. The basic assumptions for the construction of the polars and the method of analyzing the flight data are given.
Yegorov, B. N.↗
Stress Corrosion Cracking of titanium alloys - Electrochemical kinetics, SCC studies with Ti-8-1-1, SCC and polarization curves in molten salts, liquid metal embrittlement, and SCC studies with other titanium alloys Quarterly progress report, period ending 31 Dec. 1969
Stress corrosion cracking behavior in titanium, molybdenum, and aluminum alloys, and electrochemical kinetic studies
Beck, T. R.↗
The logarithmic polar curve-it's theory and application to the predetermination of airplane performance
The logarithmic polar curve has for several years been used by the most prominent aerodynamical laboratories as well as by airplane manufacturers in Europe. To show more clearly the practical application of the polar curve, a series of examples are given with suggestions for solution. After a discussion of the theory and the practical application of the polar curve, the following problems are discussed: climbing flight, speed at various altitudes, and the characteristics of two seater observation airplanes of recent design.
Cronstedt, Val↗
Characterization of Encapsulated Corrosion Inhibitors Containing Microparticles for Environmentally Friendly Smart Coatings
This poster presents the results obtained from experiments designed to evaluate the release properties, as well as the corrosion inhibition effectiveness, of several encapsulated corrosion inhibitors. Microencapsulation has been used in the development of environmentally friendly multifunctional smart coatings. This technique enables the incorporation of autonomous corrosion detection, inhibition and self-healing functionalities into many commercially available coating systems. Select environmentally friendly corrosion inhibitors were encapsulated in organic and inorganic pH-sensitive microparticles and their release in basic solutions was studied. The release rate results showed that the encapsulation can be tailored from fast, for immediate corrosion protection, to slow, which will provide continued long-term corrosion protection. The incorporation of several corrosion inhibitor release profiles into a coating provides effective corrosion protection properties. To investigate the corrosion inhibition efficiency of the encapsulated inhibitors, electrochemical techniques were used to obtain corrosion potential, polarization curve and polarization resistance data. These measurements were performed using the free as well as the encapsulated inhibitors singly or in combinations. Results from these electrochemical tests will be compared to those obtained from weight loss and other accelerated corrosion experiments.
Coatings↗
A study of the asymmetric wind of P Cygni
Results of optical linear spectropolarimetric measurements of the hypergiant P Cygni are presented. The data indicate that both the intrinsic polarization and the position angle vary with time. It is found that, prior to removing the interstellar polarization vector, the polarization varies by 0.642 percent, while the position angle takes on values between 27.0 and 39.8 deg. The wavelength dependence of the polarization curve also changes with time, indicating that the intrinsic polarization curve is not always constant with the wavelength. After a model is determined for interstellar polarization, it is found that the amplitude of the intrinsic polarization of P Cyg varies from 0.04 to 0.48 percent, with a change of 0.12 percent on successive nights. It is inferred from this large variation in the polarization on such a short timescale that the scattering material lies close to the star. Several possible geometries to describe the circumstellar material of P Cygni are presented.
Taylor, M.↗
Wing resistance near the ground
In the present treatise, a convenient method will be indicated, which makes it possible to determine the polar curve of an airplane at short distances from the ground by a simple short calculation, when the polar curve is known for flight in unlimited space.
GROUND EFFECT↗
Electrochemical approach for passivating steel and other metals and for the simultaneous production of a biocide to render water potable
Potentiostatic polarization curves indicated that the cathodic reactions in deaerated KI-I2 water solutions were due to iodine reduction and hydrogen evolution. In the presence of oxygen an additional reduction wave appeared. Anodic polarization curves revealed that iodine could be produced in the region of potential from +600 to +1000 nv vs. SCE.
Source record↗
Polarimetric observations of 9 Metis, 15 Eunomia, 89 Julia, and other asteroids.
White-light polarization curves for a number of asteorids are presented. All have well-developed negative branches, suggestive of relatively dark, texturally complex surfaces - possibly regoliths. Geometric albedos, estimated from the positive branch of the polarization curves, show that a significant dispersion in surface albedo exists within the asteroid belt.
Veverka, J.↗
Photopolarimetric observations of the minor planet Flora.
Review of the rotation period, phase coefficients, and polarization curve of the unusual asteroid Flora. It is an almost spherical asteroid whose period of rotation is probably 13.6 h, but may be only one half of this. Its surface layer consists of a dark material resembling lunar surface soil, but since the polarization curves of Flora and the moon, though generally similar, are not identical the surface of Flora must differ somewhat either in composition or in texture from that of the moon.
Veverka, J.↗
Minor planets and related objects. IX - Photometry and polarimetry of /1685/ Toro.
UBV photometry, lightcurves, a polarization-phase relation, and rotational polarization curves of Toro were obtained, June-August 1972. The average colors are B-V = 0.87 and U-B = 0.47 mag, showing some reddening with phase. The geometric albedo of Toro in the B filter is 0.14 which corresponds to an effective mean radius of 2.2 km plus or minus 0.4 (p.e.). The rotational polarization curves indicate that the lightcurves are mostly due to shape, but some albedo variation over the surface is detected as well. The shape is elongated, and probably irregular, with a cross-sectional area ratio of about 3.2, the maximum effective radius is 2.8 km and the minimum, 1.6 km.
Dunlap, J. L.↗
The Interstellar Polarization Feature Associated with the 2175 Angstrom Extinction Bump
The most successful model at fitting the wavelength dependence of interstellar extinction consists of two populations of bare silicate and graphite grains (Mathis, Rumpl & Nordsieck, (MRN)). The graphite grains are needed to fit the strong 2175 A extinction bump, with the silicates providing most of the smooth extinction seen at other wavelengths. From observations of the IR silicate absorption features, it was inferred that the silicate grains, non-spherical and aligned to the Galactic magnetic field, were responsible for the interstellar polarization. Aligned silicate grains make a very good fit to the smooth featureless UV polarization curves that comprise most of the observed sample. The lines of sight showing a UV polarization feature require something different, perhaps a second population of grains as do the fits to the extinction curve. The polarization wavelength dependence of HD 197770 can be fit by a MRN-like mixture of aligned bare silicate and graphite grains. However, none of the popular grain models including MRN envisaged an aligned bump grain population. It has been suggested that the extinction bump is not due to graphite but rather to a population of polycyclic aromatic hydrocarbons (PAHs). If the observed UV polarization features could be associated with the 2175 A bump then it would strengthen the argument that the bump must be due to grains rather than PAHs which are not likely to be aligned to the Galactic Magnetic field. The reality of ultraviolet polarization features has been confirmed by observations with ASTRO-2. The original detection toward HD 197770 has been confirmed and a new feature has been detected toward HD 147933-4. Both features have centroids lying close to 2175 A the location of the UV extinction bump. Two possibilities are considered for the source of the polarization bump, alignment of graphite grains responsible for the extinction bump or changes in the size distribution of the aligned silicate grains responsible for the continuum polarization. It seems the graphite grains are a more likely source of the polarization.
Clayton, Geoffrey C.↗
Airborne infrared polarimetry.
An airborne remote sensing study of cloud particle sizes and shapes, performed with an IR polarimeter is described. Linear polarization for a given wavelength was measured as a function of the phase angle. Liquid water clouds are found to exhibit considerable detail in their polarization curves, including a positive cloudbow near 40-degrees phase angle, and negative polarization at phase angles of less than 20 degrees and greater than (roughly) 100 degrees. A polarization vs phase angle curve obtained for thick tropical cirrus clouds showed negative polarization at large and small phase angles, and positive polarization at angles between 20 and 145 degrees. There is no indication of a cloudbow or other detailed structure.
Coffeen, D. L.↗