Normaliz: Algorithms for Affine Monoids and Rational Cones

Normaliz is a program for solving linear systems of inequalities. In this paper we present the algorithms implemented in the program, starting with version 2.0

ASSESSING THE EFFECTIVENESS OF COMPETITION POLICY IN ROMANIA USING CLUSTERS AND DISTANCES METHODS

For European competition policy, assessing the effectiveness of its enforcements turned out to be a problematic issue. Thus, it has proved to be difficult to assess whether the objectives are properly defined and subsequently the extent that these were achieved, whether the institutional and legal framework are well chosen and ultimately whether the actions of competition authorities produce the desired outcome as long as the performances of these institutions are not quantified in one way or another. Based upon clusters and distances methods this paper highlights the main disparities between Romania and other Member States regarding the perceived effectiveness of competition policy enforcement. Which seems to be obvious for Romania is the fact that it has the legal and also the institutional framework required to ensure a normal competitive environment, but unfortunately it is not credible and therefore is not considered as an improving competitive environment factor as long as its effects on the market are elusive for companies and consumers.competition policy, effectiveness, clusters, distances

On toric face rings

Following a construction of Stanley we consider toric face rings associated to rational pointed fans. This class of rings is a common generalization of the concepts of Stanley--Reisner and affine monoid algebras. The main goal of this article is to unify parts of the theories of Stanley--Reisner- and affine monoid algebras. We consider (non-pure) shellable fan's and the Cohen--Macaulay property. Moreover, we study the local cohomology, the canonical module and the Gorenstein property of a toric face ring.Comment: 22 pages; Revised version of the pape

Estimation of cement thermal properties through the three-phase model with application to geothermal wells

Geothermal energy has been used by mankind since ancient times. Given the limited geographical distribution of the most favorable resources, exploration efforts have more recently focused on unconventional geothermal systems targeting greater depths to reach sufficient temperatures. In these systems, geothermal well performance relies on efficient heat transfer between the working fluid, which is pumped from surface, and the underground rock. Most of the wells designed for such environments require that the casing strings used throughout the well construction process be cemented in place. The overall heat transfer around the wellbore may be optimized through accurate selection of cement recipes. This paper presents the application of a three-phase analytical model to estimate the cement thermal properties. The results show that cement recipes can be designed to enhance or minimize heat transfer around wellbore, extending the application of geothermal exploitation