Online support groups: an overlooked resource for patients

Online support groups: history, research, and source

Automatic recognition and characterisation of supergranular cells from photospheric velocity fields

We have developed an exceptionally noise resistant method for accurate and automatic identification of supergranular cell boundaries from velocity measurements. Due to its high noise tolerance the algorithm can produce reliable cell patterns with only very small amounts of smoothing of the source data in comparison to conventional methods. In this paper we describe the method and test it with simulated data. We then apply it to the analysis of velocity fields derived from high-resolution continuum data from MDI (Michelson Doppler Imager) on SOHO. From this, we can identify certain basic properties of supergranulation cells, such as their characteristic sizes, the flow speeds within cells and their dependence on cell areas at high resolution. The effect of the noise and smoothing on the derived cell boundaries is investigated and quantified using simulated data. We show in detail the evolution of supergranular cells over their lifetime, including observations of emerging, splitting, and coalescing cells. A key result of our analysis of cell internal velocities is that there is a simple linear relation between cell size and cell internal velocity, rather than the power law usually suggested

A Comparison of Coated Paper Surfaces by Photomicrography

Five different types of coated papers were photomicrographed, namely cast coated, roll coated, trailing blade coated, air brush coated, and brush coated grades. All cast coated papers were found to be extremely smooth and essentially free of pattern. Roll coated papers displayed a microscopic pattern which resembled the magnified surface of an orange peel. Trailing blade coated papers displayed sharp-edged pits and, in some cases, scuffed surfaces. Air brush coated papers had a microscopic pattern which resembled the non-magnified surface of a pie crust. Brush coated papers closely resembled air brush coated papers microscopically, however, they also carried a macroscopic pattern of brush marks which distinguished them from the air brush coated grades. It was concluded that various types of coating processes leave typical patterns which may be used in conjunction with other characteristics of the paper to identify the particular coating process used

Evidence of photospheric vortex flows at supergranular junctions observed by FG/SOT (Hinode)

Twisting motions of different nature are observed in several layers of the solar atmosphere. Chromospheric sunspot whorls and rotation of sunspots or even higher up in the lower corona sigmoids are examples of the large scale twisted topology of many solar features. Nevertheless, their occurrence at large scale in the quiet photosphere has not been investigated. The present study reveals the existence of vortex flows located at the supergranular junctions of the quiet Sun. We use a 1-hour and a 5-hour time series of the granulation in Blue continuum and G-band images from FG/SOT to derive the photospheric flows. A feature tracking technique called Balltracking is performed to track the granules and reveal the underlying flow fields. In both time series we identify long-lasting vortex flow located at supergranular junctions. The first vortex flow lasts at least 1 hour and is ~20-arcsec-wide (~15.5 Mm). The second vortex flow lasts more than 2 hours and is ~27-arcsec-wide (~21 Mm).Comment: 4 pages, 10 figure

Saturated hydrocarbon polymeric binder for advanced solid propellant hybrid solid grain Quarterly report, May 1 - Jul. 31, 1967

Glass transition temperature measurement - telomer preparation and reaction