Element abundances

Element Abundance Element Abundance Element Abundance... 

Element Abundance, % Amount in 3.5 km of cmst, t Element Abundance, % Amount in 3.5 km of cmst, t... 

Titanium is the ninth most abundant element ia the earth s cmst, at approximately 0.62%, and the fourth most abundant stmctural element. Its elemental abundance is about five times less than iron and 100 times greater than copper, yet for stmctural appHcations titanium s aimual use is ca 200 times less than copper and 2000 times less than iron. Metal production began in 1948 its principal use was in military aircraft. Gradually the appHcations spread to commercial aircraft, the chemical industry, and, more recently, consumer goods. 

Taken from W. S. Fyfe, Geochemistry, Oxford University Press, 1974, with some modifications and additions to incorporate later data. The detailed numbers are subject to various assumptions in the models of the global distribution of the various rock types within the crust, but they are broadly acceptable as an indication of elemental abundances. See also Table 1 in C. K. J0RGENSEN, Comments Astrophys. 17, 49-101 (1993). 

Abundance of elements in earth s crust, see Elements, abundance in earth s crust Acetaldehyde structure, 332 Acetamide, 338 Acetanilide, 344 Acetic acid in biochemistry, 428 structure, 333 Acetone... 

Element Abundance Cross Section, barns Nuclide Half-Life y-photopeak, MeV... 

The examples discussed above suggest useful directions for future research involving trace element analysis of bones. Specifically, the effects of developmental age and other factors (e.g., porosity, mineralization) that may lead to differences in surface area of specimens should be considered. Diage-netic effects should be monitored by analysis of a suite of elements whose abundances are not controlled by dietary abundances (e.g., Mn, Zr, etc.). Finally, although alkaline elements such as Sr and Ba are most likely to reflect the Sr/Ca and Ba/Ca levels of the diet, omnivores such as humans are likely to obtain the majority of these elements from plants rather than from animals. Therefore for accmate diet reconstruction it is necessary to determine the total abundance of Ca as and the Sr/Ca and Ba/Ca ratios of the plant and animal resources that were potential dietary staples. The effects of culinary practices on elemental abundances (Burton and Wright 1995 Katzenberg et al. this volume) must also be evaluated. 

We see that the total element abundance on the continental crust of Earth today (see Figures 1.4 and 1.5), is poorly reflected in the availability of the elements in the sea. Two major reactions affected the availability of the non-metals and the metals apart from abundances both concern solubility of salts ... 

In this paper I discuss overall metallicity, a measure of the overall heavy-element abundance in the star, and direct determination of elemental abundances and abundance ratios of Fe, O, the a-elements Mg, Si, Ca, and Ti, and also the light elements Na and Al. 

Ultimately, however, one seeks abundances from high-resolution spectroscopy, and a full elemental abundance analysis. Data on a broad range of elemental abundances in open clusters have been limited until recently. Fortunately, this situation is beginning to change. 

Only recently have large numbers of open clusters become the subject of elemental abundance determinations other than those of the lightest elements (Li, C). A survey of the literature (not guaranteed to be complete), including some unpublished data kindly made available for this contribution, revealed [Fe/H] determinations for 45 open clusters. Of these, 33 have determinations of at least some of the a-elements, and these are collected in Table 1. There are very few clusters in common between studies, so it is not possible to investigate systematic differences between studies, nor to bring these measures to a common system. 

Abstract. The Milky Way harbours two disks that appear distinct concerning scale-heights, kinematics, and elemental abundance patterns. Recent years have seen a surge of studies of the elemental abundance trends in the disks using high resolution spectroscopy. Here I will review and discuss the currently available data. Special focus will also be put on how we define stars to be members of either disk, and how current models of galaxy formation favour that thick disks are formed from several accreted bodies. The ability for the stellar abundance trends to test such predictions are discussed. 

Based on currently available elemental abundance data and age determinations, the thick disk could have formed either through a violent, heating merger or through accretion of (substantial) satellites in a hierarchical galaxy formation scenario. The fast monolithic-like collapse is getting more and more problematic as data are gathered. It would be especially crucial to establish if there is an age-metallicity relation in the thick disk or not as in that case the thick disk could not have formed in that way (since the models indicate that the formation time-scale for the stars in the thick disk would be very short, see [7]). 

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... 

Elemental abundances were determined by spectral synthesis of individual lines, compared to observed spectra obtained with the FEROS spectrograph at the ESO-1.5m telescope. 

Light- and Heavy-Element Abundances from Mid-UV and Optical Spectral Syntheses... 

Elemental Abundances in 10 Dwarfs of the Galactic Thick Disk... 

Abstract. The most recently discovered Galactic component - thick disk - still needs high-resolution spectral investigations since its origin and evolution is not understood enough. Elemental abundance ratios in the metallicity range —0.68 < [Fe/H] < —0.10 were determined in a sample of 10 thick-disk dwarfs and compared with results of other stars investigated as well as with models of thin disk chemical evolution. 

Recent surveys of metal-deficient stars have discovered a large number of carbon-rich objects, with a marked increase in their frequency at [Fe/H] < —2.5. In order to constrain the origin(s) of their carbon excesses, we have performed elemental abundance analyses for 40 objects selected from candidate metal-poor stars with strong CH G bands identified in the HK and Hamburg/ESO surveys. High-resolution spectroscopy has been obtained with AAT/UCLES and Subaru/HDS a portion of these studies have already been published [1—3]. 

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