The Platinum Loop Group

Platinum and the Metals of the Platinum Group.

WHAT promises to be the most complete and authoritative work on platinum and platinum deposits is about to be published in Geneva, Switzerland. The author, Louis Duparc, is professor of chemistry and petrology in the University of Geneva; the name of Marguerite N. Tikonovitch is announced as that of the associate author.' Professor Duparc has long been known as the writer of many papers on the ...

Accumulation of Platinum Group Elements

Accumulation of Platinum Group Elements by the Marine Microalga, Chlorella stigmatophora Leyla Shams Very little information exists on the marine biogeochemistry of Rh, Pd and Pt, or the platinum group elements (PGE), an emerging group of contaminants whose priiicipal emissions are associated with the abrasion of the catalytic converter in motor vehicles and chemotherapy drugs discharged in hos...

Promotion of the Cupellation Method for Accurate Determination of Gold Alloy’s Karat Containing Platinum-Group Metals

The main standard method for gold karat determination is the cupellation method. However, this method is not sufficiently accurate to determine gold karat in the presence of insoluble Platinum–Group Metals (PGMs), such as Ir, Ru, and Rh. In this study, for the first time, a complementary method that can be used coupled with the reference cupellation method is presented for the high...

The Loop Group and the Cobar Construction

We prove that for any 1-reduced simplicial set X, Adams’ cobar construction ΩCX on the normalised chain complex of X is naturally a strong deformation retract of the normalised chains CGX on the Kan loop group GX. In order to prove this result, we extend the definition of the cobar construction and actually obtain the existence of such a strong deformation retract for all 0-reduced simplicial s...

Chromite – Platinum-Group Element Magmatic Deposits