Abstract. We construct several families of Artin-Schelter regular algebras of global dimension four using double Ore extension and then prove that all these algebras are strongly noetherian, Auslander regular, Koszul and CohenMacaulay domains. Many regular algebras constructed in the paper are new and are not isomorphic to either a normal extension or an Ore extension of an Artin-Schelter regul...

Introduction This paper seeks to define a new method for representing and managing description of archival collections using OAI-ORE. This new method has two advantages. Firstly, it adapts traditional archival description methods for the contemporary reality that digital collections, unlike collections of physical materials, are not best described by physical location. Secondly, it takes advant...

Necessary and sufficient conditions for an Ore extension S = R[x;σ, δ] to be a PI ring are given in the case σ is an injective endomorphism of a semiprime ring R satisfying the ACC on annihilators. Also, for an arbitrary endomorphism τ of R, a characterization of Ore extensions R[x; τ ] which are PI rings is given, provided the coefficient ring R is noetherian.

in this study, the isothermal reduction of iron oxide pellets, made of iranian chadormalo, gole-gohar, and sangan iron ores, was investigated in the temperature range of 900-1100°c. tabas, pabdana, babnizoo, karmozd, and shahrood domestic coals were used as reductants. parametric studies were performed and the effects of such factors as temperature, average particle size of iron ore and coal fi...

Iron ore concentrate is enriched by flotation prior to form iron ore green pellets in order to reduce phosphorus content in the ore concentrate. A flotation reagent is used in this process and it is known to incorporate air bubbles and eventually deteriorate the strength of the pellets. These bubbles were therefore characterized both qualitatively and quantitatively by cryogenic scanning electr...

Recent theories of concepts have raised the issue of how people combine simple concepts (like engine and repalr) to form complex concepts (like engine repalr). This article approaches this issue by asking how people comprehend modified noun phrases of this sort. One explanation of how complex concepts are understood (the feature weighting model) provides a simple mechanism in which the primary ...

Since 2010, Nigerian state and federal governments and the international community have been responding to an outbreak of lead poisoning caused by the processing of lead-containing gold ore in Zamfara State, Nigeria, that resulted in the deaths of approximately 400 children aged ≤ 5 years. Widespread education, surveys of high-risk villages, testing of blood lead levels (BLLs), medical treatmen...

We show that the computation of the Popov form of Ore polynomial matrices can be formulated as a problem of computing the left nullspace of such matrices. While this technique is already known for polynomial matrices, the extension to Ore polynomial matrices is not immediate because multiplication of the matrix entries is not commutative. A number of results for polynomial matrices are extended...

Recent research on BIF-related high-grade iron ore mineralization has resulted in new genetic models that emphasize the structurally controlled hypogene alteration and upgrade of BIF to high-grade (>65% Fe) iron ore. Conventional structural and stratigraphic mapping and reconstructions of the tectonic history of iron districts, in combination with high-tech geochemical analyses such as laser IC...