Granulation, solar

Electrodialysis. Electro dialytic membrane process technology is used extensively in Japan to produce granulated—evaporated salt. Filtered seawater is concentrated by membrane electro dialysis and evaporated in multiple-effect evaporators. Seawater can be concentrated to a product brine concentration of 200 g/L at a power consumption of 150 kWh/1 of NaCl (8). Improvements in membrane technology have reduced the power consumption and energy costs so that a high value-added product such as table salt can be produced economically by electro dialysis. However, industrial-grade salt produced in this manner caimot compete economically with the large quantities of low cost solar salt imported into Japan from Austraha and Mexico. 

Figure 6.5 The Swedish Vacuum Solar Telescope on La Palma in the Canary Islands. This device was used to capture the granulation image in figure 6.4. 

A solar granule is about the size of the state of California. 

A solar granule (bubble) is 400 degrees K warmer than the dark intergranular network of lanes that surrounds the granule. 

Solar granules are like bubbles on the top of boiling tomato soup. Heat is supplied from below and carried upward through the process of convection. The cool liquid on top of the soup sinks. 

About 40 percent of the solar granules explode, vomiting their material into the solar atmosphere at speeds of 1,000 miles per hour (or about 500 meters per second). If we could hear sound waves across the vacuum of space that separates us from the Sun, we would hear a thunderous roar accompanying each granulation eruption. 

Dainis Dravins, Luund Observatory, Solar granules the solar photosphere in white light, http //nastol.astro.lu.se/ dainis/HTML/SOLAR.html... 

Solar granule information comes from Amara Graps, Stanford Solar Center, Solar granulation quiz http //solar-center.stanford.edu/cgi-bin/quiz2.pl/granule quiz.html... 

Solar atmospheric models have evolved from one dimension to more complicated 2D and 3D models designed to take into account effects of convection and granulation on radiative transfer in the solar atmosphere. Recent applications of 3D models instead of older ID models leads to lower abundances of several elements, notably oxygen, from previously determined values. Significant reductions of photospheric abundances in other elements (e.g., Na, Al, Si) were also found (see, e.g., [15]). However, different 3D model assumptions lead to different results, see for example the discussion by [29] for silicon. 

Reim, M., Komer, W., Manara, J., Korder, S., Arduini-Schuster, M., Ebert, H.P. and Fricke, J., Silica aerogel granulate material for thermal insulation and dayUghting. Solar Energy, 2005. 79(2) p. 131-139. 

TURON and LENA (1970) have obtained lOy high resolution images of the solar surface, which show the low frequency tail of the granulation at 1-2 arc sec sizes. 

To account for all the properties of the latent image much more complicated assumptions are necessary. These cannot be taken up here, but it is quite possible that a colloidal point of view may be employed for the explanation of solarization and other little understood phenomena. The author would like to call attention to a not widely known experiment of Kogelmann,t by which it is shown that with normally exposed plates developed in acid solution containing iron, the substance of the latent image lies on the surface of the granules, while this substance is in the granules in the case of solarized plates. 

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