32 research outputs found
Real and imaginary chemical potential in 2-color QCD
In this paper we study the finite temperature SU(2) gauge theory with
staggered fermions for non-zero imaginary and real chemical potential. The
method of analytical continuation of Monte Carlo results from imaginary to real
chemical potential is tested by comparison with simulations performed {\em
directly} for real chemical potential. We discuss the applicability of the
method in the different regions of the phase diagram in the temperature --
imaginary chemical potential plane.Comment: 15 pages, 7 figures; a few comments added; version published on Phys.
Rev.
Remarks on the multi-parameter reweighting method for the study of lattice QCD at non-zero temperature and density
We comment on the reweighting method for the study of finite density lattice
QCD. We discuss the applicable parameter range of the reweighting method for
models which have more than one simulation parameter. The applicability range
is determined by the fluctuations of the modification factor of the Boltzmann
weight. In some models having a first order phase transition, the fluctuations
are minimized along the phase transition line if we assume that the pressure in
the hot and the cold phase is balanced at the first order phase transition
point. This suggests that the reweighting method with two parameters is
applicable in a wide range for the purpose of tracing out the phase transition
line in the parameter space. To confirm the usefulness of the reweighting
method for 2 flavor QCD, the fluctuations of the reweighting factor are
measured by numerical simulations for the cases of reweighting in the quark
mass and chemical potential directions. The relation with the phase transition
line is discussed. Moreover, the sign problem caused by the complex phase
fluctuations is studied.Comment: 20 page, 6 figure
The Role of Topoisomerase II in Meiotic Chromosome Condensation and Segregation in Schizosaccharomyces pombe
ResistĂȘncia Ă corrosĂŁo de junta dissimilar soldada pelo processo TIG composta pelos aços inoxidĂĄveis AISI 316L e AISI 444
Corrosion Inhibitors for Sour Oilfield Environment (H2S Corrosion)
Lower-grade steel materials are the most commonly used construction materials for oil and gas wells
due to their low cost and high performance. However, they are susceptible to corrosion when they
come in contact with corrosive environments that are highly acidic. In oil wells, particularly deep oil
wells, hydrogen sulfide (H2S) is commonly found. The dissolution of H2S gas in produced water
makes the fluid corrosive. The use of corrosion inhibitors is perhaps the most practical and costeffective
means of controlling corrosion of low carbon steels in the sour environment. In this chapter,
typical corrosion inhibitors used in oil and gas fields to control the internal corrosion of oilfield
equipment caused by H2S are being examined. The inhibitors found to be effective are polar
functional compounds, with many being based on nitrogen-containing compounds, such as amines,
imidazolines, and quaternary ammonium salts. Drawbacks of these compounds in practical
applications and potentials of future developments are discussed
Development of a knowledge-based system for materials management
In the past, many mistakes have been made in selecting the best materials for a given task. Thus, tools for humans to optimise the selection of materials will be valuable assets, particularly when the field of application is broad, the problem complex, the operating envelope variable, or the environment is aggressive. In this paper, a methodology for construction of a generic computer materials selector is described. A knowledge structure is presented in which materials selection and failure analysis are at opposite ends of a spectrum of materials performance. An example of the selection of a coating for marine use is given. Besides being of great value to designers, the tool is of considerable potential use for general materials information systems and computer-based learning module