scholarly journals Asteroid Polarimetry: A Progress Report

1971 ◽  
Vol 12 ◽  
pp. 91-94
Author(s):  
J. Veverka
Keyword(s):  
Present Status ◽  
Progress Report ◽  
Polarization Curves ◽  
Photographic Method ◽  
Polarization Measurements ◽  
Partial Data ◽  
Low Sensitivity ◽  
Photoelectric Measurements

This is a brief report on the present status of asteroid polarimetry. A detailed paper is in preparation jointly with T. Gehrels.The first polarization measurements of asteroids were made by Lyot (1934), who photographically determined the polarization curves of Ceres and Vesta. These curves are reproduced by Dollfus (1961). Unfortunately, because of the low sensitivity of the photographic method, they do not agree very well with recent photoelectric measurements.The first photoelectric polarization measurements of asteroids were made by Provin (1955) (details of this work are given by Dollfus, 1961), and in recent years this work has been extended by Gehrels (unpublished) and by Veverka (1970). To date, fairly complete polarization curves for about a dozen asteroids have been obtained, and at least partial data are available for twice that number.

Corrosion Inhibition of Sodium Hexametaphosphate for Carbon Steel in KCl Solution

2014 ◽  
Vol 886 ◽  
pp. 12-15
Author(s):  
Bin Huang ◽  
Kang Quan Qiao ◽  
Yi Shun Cui
Keyword(s):  
Weight Loss ◽  
Electron Microscope ◽  
Carbon Steel ◽  
Corrosion Inhibition ◽  
Potentiodynamic Polarization ◽  
Polarization Curves ◽  
Sodium Hexametaphosphate ◽  
Anodic Process ◽  
Polarization Measurements ◽  
Potentiodynamic Polarization Curves

The influence of sodium hexametaPhosphate on the corrosion of carbon steel in 0.5 mol•L-1 KCl solution at 25 °C was investigated using weight loss measurements, potentiodynamic polarization curves and Scan electron microscope (SEM). The obtained results show that sodium hexametaPhosphate is an excellent inhibitor and the inhibition efficiencies exceed 87 %. The polarization measurements reveal that sodium hexametaPhosphate is an inhibitor mainly controlled by anodic process.

Improved Data Recording for Automatic Potentiodynamic Polarization Measurements

CORROSION ◽  
1968 ◽  
Vol 24 (9) ◽  
pp. 298-300 ◽  
Author(s):  
W. D. FRANCE ◽  
R. W. LIETZ
Keyword(s):  
Potentiodynamic Polarization ◽  
Polarization Curves ◽  
Electrical Noise ◽  
Data Recording ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Polarization Measurements ◽  
Potentiodynamic Polarization Curves ◽  
Low Pass ◽  
Logarithmic Converter

Abstract Improvements in instrumentation for automatically plotting potentiodynamic polarization curves by using a scanning potentiostat, a logarithmic converter, and an X-Y recorder are described. An accessory circuit permits uninterrupted recording of polarization currents from 10−2 to 107 μa and virtually eliminates operator attention. In addition, a low-pass filter reduces extraneous electrical noise in the electrochemical circuit and thereby provides smooth experimental curves.

scholarly journals Common continuum polarization properties: a possible link between proto-planetary nebulae and Type Ia Supernova progenitors

2017 ◽  
Vol 471 (2) ◽  
pp. 2111-2116 ◽  
Author(s):  
Aleksandar Cikota ◽  
Ferdinando Patat ◽  
Stefan Cikota ◽  
Jason Spyromilio ◽  
Gioia Rau
Keyword(s):  
Planetary Nebulae ◽  
Asymptotic Giant Branch ◽  
Polarization Curves ◽  
Circumstellar Dust ◽  
Agb Stars ◽  
Polarization Measurements ◽  
The Core ◽  
Type Ia Supernova ◽  
Type Ia

Abstract The lines of sight to highly reddened SNe Ia show peculiar continuum polarization curves, growing towards blue wavelengths and peaking at $\lambda _{\text{max}} \lesssim 0.4 \,\mu \mathrm{m}$, like no other sightline to any normal Galactic star. We examined continuum polarization measurements of a sample of asymptotic giant branch (AGB) and post-AGB stars from the literature, finding that some proto-planetary nebulae (PPNe) have polarization curves similar to those observed along SN Ia sightlines. These polarization curves are produced by scattering on circumstellar dust. We discuss the similarity and the possibility that at least some SNe Ia might explode during the post-AGB phase of their binary companion. Furthermore, we speculate that the peculiar SN Ia polarization curves might provide observational support to the core-degenerate progenitor model.

Spectrophotometric measurements of objective-prism spectra

1966 ◽  
Vol 24 ◽  
pp. 118-119
Author(s):  
Th. Schmidt-Kaler
Keyword(s):  
Progress Report ◽  
Two Dimensional ◽  
Objective Prism ◽  
Made In

I should like to give you a very condensed progress report on some spectrophotometric measurements of objective-prism spectra made in collaboration with H. Leicher at Bonn. The procedure used is almost completely automatic. The measurements are made with the help of a semi-automatic fully digitized registering microphotometer constructed by Hög-Hamburg. The reductions are carried out with the aid of a number of interconnected programmes written for the computer IBM 7090, beginning with the output of the photometer in the form of punched cards and ending with the printing-out of the final two-dimensional classifications.

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