Stars classes

Silicon is present in the sun and stars and is a principal component of a class of meteorites known as aerolites. It is also a component of tektites, a natural glass of uncertain origin. 

Iron is a relatively abundant element in the universe. It is found in the sun and many types of stars in considerable quantity. Its nuclei are very stable. Iron is a principal component of a meteorite class known as siderites and is a minor constituent of the other two meteorite classes. The core of the earth — 2150 miles in radius — is thought to be largely composed of iron with about 10 percent occluded hydrogen. The metal is the fourth most abundant element, by weight that makes up the crust of the earth. 

Anionic polymerisation techniques aie one of many ways to synthesise a special class of block copolymers, lefeiied to as star block copolymers (eq. 25) (33). Specifically, a "living" SB block is coupled with a silyl haUde coupling agent. The term living polymerisation refers to a chain polymerisation that proceeds in the absence of termination or transfer reactions. 

Numerous analyses of data routinely collected in the United States have been performed by the U.S. National Climatic Center, results of these analyses are available at reasonable cost. The joint frequency of Pasquill stability class, wind direction class (primarily to 16 compass points), and wind speed class (in six classes) has been determined for various periods of record for over 200 observation stations in the United States from either hourly or 3-hourly data. A computer program called STAR (STability ARray) estimates the Pasquill class from the elevation of the sun (approximated from the hour and time of year), wind speed, cloud cover, and ceiling height. STAR output for seasons and the entire period of record can be obtained from the Center. Table 21-2 is similar in format to the standard output. This table gives the frequencies for D stability, based on a total of 100 for all stabilities. 

Now take another example from the service industry accommodation. There are various categories, such as rented, leased, and purchased. In the rented category there are hotels, inns, guest houses, apartments, etc. It would be inappropriate to compare hotels with guest houses or apartments with inns. They are each in a different class. Hotels are a class of accommodation within which are grades such as 5 star, 4 star, 3 star, etc., indicating the facilities offered. 

Mr. DeGroff is teaching a cocktail college at the Marriott Marquis on Broadway, one class a month on categories of drinks. Last month s class, the first, was on the martini. I called Mr. DeGroff and asked him if he had had a star pupil and he said yes without hesitation. 

Star polymers are a class of polymers with interesting rheological and physical properties. The tetra-functionalized adamantane cores (adamantyls) have been employed as initiators in the atom transfer radical polymerization (ATRP) method applied to styrene and various acrylate monomers (see Fig. 21). 

Unlike prisms, in this class of bodies uniqueness requires knowledge of the density. This theorem was proved by P. Novikov. The simplest example of starshaped bodies is a spherical mass. Of course, prisms are also star-shaped bodies but due to their special form, that causes field singularities at corners, the inverse problem is unique even without knowledge of the density. It is obvious that these two classes of bodies include a wide range of density distributions besides it is very possible that there are other classes of bodies for which the solution of the inverse problem is unique. It seems that this information is already sufficient to think that non-uniqueness is not obvious but rather a paradox. 

MHI possess at least two different polymerization initiating sites. The identical sites are selective for a particular class of monomers, and thus the resulting ji-star consists of chemically different arms. In order to obtain well-defined //-stars, these identical active sites should have equal reactivity and furthermore, initiation should be faster than propagation. It is not always possible to achieve these requirements since differentiation in the topology of... 

Nowadays it is widely accepted that the 13C(a, n)160 reaction is the main source or neutrons of the s-process in AGB stars. Comparison between the s-element abundance patterns found in AGB stars of different classes and metallicity with theoretical predictions show a nice agreement (see e.g. Busso et al. 2001 and references therein). This comparison would indicate also that, at a given stellar metallicity, a dispersion in the quantity of 13C burnt may exists as one would expect, on the other hand. In fact, s-element patterns for individual stars can be fitted assuming that the amount of 13C burnt ranges from 10 7 to almost 10-5 Mq. However, the large error bar in the abundances precludes to put more... 

According to the Fig. 1, Ba is more overabundant than La in Barium stars relative to normal stars with similar metallicities. No dependence on luminosity classes was found in the s/r behavior among those Barium stars. 

The drawback of this kind of studies is that no reliable indicator of the O abundance is available moreover, informations on the Na abundances are difficult to obtain. However, thanks to the new generation of efficient spectrographs mounted at 8-10m class telescopes, high resolution spectra for unevolved stars in GCs are feasible. 

Two classes of stars are presently suggested, IM-AGB stars and RGB stars slightly more massive than the present turn-off mass ([12]). Both are able to provide the ON and NeNa cycles in H burning (in shell in RGB stars and at the base of the convective envelope in AGB) and a mechanism to bring to the surface and then eject the matter, polluting other stars. 

High resolution and high S/N spectra of 32 metal poor stars observed with various 4-m class telescopes (Israelian et al. 1998, 2001, Bihain et al. 2004) have been used to analyse N/O and C/O ratios from near-UV molecular lines of CH, NH and OH. We have carried out an independent study of the (N/O) ratio using the NH band at 3360 A and the OH lines employed by Israelian et al. (1998, 2001). Details of the analysis and stellar parameters are provided in Israelian et al. (2004). 

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