A Formal Theory of Substances, Qualities, and Universals

One of the tasks of ontology in information science is to support the classification of entities according to their kinds and qualities. We hold that to realize this task as far as entities such as material objects are concerned we need to distinguish four kinds of entities: substance particulars, quality particulars, substance universals, and quality universals. These form, so to speak, an ontological square. We present a formal theory of classification based on this idea, including both a semantics for the theory and a provably sound axiomatization

Anisotropic Outflows and IGM Enrichment

We have designed an analytical model for the evolution of anisotropic galactic outflows. These outflows follow the path of least resistance, and thus travel preferentially into low-density regions, away from cosmological structures where galaxies form. We show that anisotropic outflows can significantly enrich low-density systems with metals.Comment: Proceedings of Chemodynamics 2006, Lyon, 2 pages, 1 figure, style file include

Transforming the Einstein static Universe into physically acceptable static fluid spheres II: A two - fold infinity of exact solutions

Following a solution generating technique introduced recently by one of us, we transform the Einstein static Universe into a two - fold infinity class of physically acceptable exact perfect fluid solutions of Einstein's equations. Whereas the entire class of solutions can be considered as generalizations of the familiar Tolman IV solution, no member of the class can be written explicitly in isotropic coordinates. Further, except for a set of measure zero, no member of the class can be written explicitly in curvature coordinates either.Comment: 6 pages, 6 figures, revtex4,improved figures. To appear in Phys. Rev.

Unsteady effects of a control surface in two dimensional subsonic and transonic flow

The experimental results of steady and unsteady pressure measurements, carried out in subsonic and transonic flow on a 16 percent relative thickness supercritical aerofoil, equipped with a trailing edge flap involving 25 percent of the chord, in a sinusoidal motion are given. These experimental results are compared with those obtained by various methods of steady and unsteady inviscid flow calculations. Some calculation results in which viscous effects have been taken into account, for both steady and unsteady flows, are also presented

World oil resources: their assessment and potential for the twenty-first century.

Summarizes the various assessments of world conventional oil resources and unconventional (eg tar sands, heavy crude, oil shales). Outlines the three factors that fostered the still-rising oil costs: the shift to smaller fields; the move to offshore fields; and the shift to exploiting unconventional sources

Long Term Energy Strategies

Because-of the long lead times in the energy sector and long market penetration periods, decision making must be prepared early. But uncertainties, and especially the uncertainty of future energy demand, make it a difficult task. Among possible methods of comparing energy options, the WELMM approach has been developed, and is introduced

World Oil Resources Assessment and Potential for the 21st Century

Over the last thirty there have been about two dozen estimates made for world oil resources. Few of them are really independent or new estimates. Moreover, most of them disclose neither the method of assessment which was used nor the data on which the estimates rely. The situation is worse still for unconventional world oil resources such as heavy oil, tar sands, and oil shales. This is the reason why IIASA has launched an up-dating survey of past (and sometimes very old) estimates. This paper summarizes the efforts of the Resources Group to better understand both world oil (conventional and unconventional) estimates and also some technological and/or economic factors affecting the future availability of liquid fuel