A six-parameter space to describe galaxy diversification

Galaxy diversification proceeds by transforming events like accretion, interaction or mergers. These explain the formation and evolution of galaxies that can now be described with many observables. Multivariate analyses are the obvious tools to tackle the datasets and understand the differences between different kinds of objects. However, depending on the method used, redundancies, incompatibilities or subjective choices of the parameters can void the usefulness of such analyses. The behaviour of the available parameters should be analysed before an objective reduction of dimensionality and subsequent clustering analyses can be undertaken, especially in an evolutionary context. We study a sample of 424 early-type galaxies described by 25 parameters, ten of which are Lick indices, to identify the most structuring parameters and determine an evolutionary classification of these objects. Four independent statistical methods are used to investigate the discriminant properties of the observables and the partitioning of the 424 galaxies: Principal Component Analysis, K-means cluster analysis, Minimum Contradiction Analysis and Cladistics. (abridged)Comment: Accepted for publicationin A\&

The Magnetic Fraction of Coal Fly Ash: Its Separation, Properties, and Utilization

A laboratory-size electromagnetic device has been built to separate the high-iron magnetic fraction from coal fly ash. Fly ash, the fine particulate matter produced when pulverized coal is burned, contains an average of 18 wt. percent iron expressed as Fe2O3 found in a distinctive fraction of finely divided, dense, largely spheroidal particles of high magnetic susceptibility. Seventy to eighty percent of the iron in bituminous coal fly ash is found in this fraction which represents about 20 weight percent or 10 volume percent of the fly ash. In this work the iron-rich fraction has been characterized as to particle size, composition, and density. It appears to have a market potential as a material for preparation of high-density media used in coal washing and other mineral dressing processes. Dense-media material, which costs about $100 per metric ton, is being utilized in increasingly large quantities as the demand for washed coal expands. The magnetic fraction also appears to have potential as a source of iron. If further processing can reduce the silica level found in the fraction as it is separated from the ash, pellets with a composition similar to taconite can be prepared for use as blast furnace feed. Separation and use of this fraction of the coal ash could be profitable for utility companies and could be the beginning of the utilization of the large amount of ash which now constitutes a waste disposal problem

Recovery of Alumina From Coal Fly Ash By High Temperature Chlorination

The recovery of metals from low value sources will help reduce our national demand for foreign resources. The ash from bituminous type coals contains about 20 percent aluminum oxide and 20 percent iron oxides by weight. Recovery of these metals would provide an alternate source to the ores now used. The iron and aluminum materials in fly ash are recoverable by high temperature chlorination. Passing dry chlorine gas through a bed of nonmagnetic fly ash maintained at 850 to 900 degrees C. chlorinates the iron and aluminum constituents forming volatile compounds which are carried from the bed by the exit gas stream. In exploratory runs, 55 percent of the aluminum has been recovered as aluminum chloride in a nearly silica-free state

Optical and Radio Polarimetry of the M87 Jet at 0.2" Resolution

We discuss optical (HST/WFPC2 F555W) and radio (15 GHz VLA) polarimetry observations of the M87 jet taken during 1994-1995. Many knot regions are very highly polarized ($\sim 40-50$, approaching the theoretical maximum for optically thin synchrotron radiation), suggesting highly ordered magnetic fields. High degrees of polarization are also observed in interknot regions. While the optical and radio polarization maps share many similarities, we observe significant differences between the radio and optical polarized structures, particularly for bright knots in the inner jet, giving us important insight into the jet's radial structure. Unlike in the radio, the optical magnetic field position angle becomes perpendicular to the jet at the upstream ends of knots HST-1, D, E and F. Moreover, the optical polarization decreases markedly at the position of the flux maxima in these knots. In contrast, the magnetic field position angle observed in the radio remains parallel to the jet in most of these regions, and the decreases in radio polarization are smaller. More minor differences are seen in other jet regions. Many of the differences between optical and radio polarimetry results can be explained in terms of a model whereby shocks occur in the jet interior, where higher-energy electrons are concentrated and dominate both polarized and unpolarized emissions in the optical, while the radio maps show strong contributions from lower-energy electrons in regions with {\bf B} parallel, near the jet surface.Comment: 28 pages, 7 figures; accepted for publication in AJ (May 1999