7,435 research outputs found
Market Power in Mixed Hydro-Thermal Electric Systems
This paper shows that, unlike what has been found in other papers, a hydro reservoir is an effective tool to exercise market power. Its appealing as a tool is enhanced by the fact that there is no need to constrain total hydro production - a practice too easy to detect -; it suffices to distort the intertemporal allocation of hydro production over time. A hydro-producer may increase his profits by exploiting differences in price elasticity of demand across periods, allocating too little supply to less elastic periods and too much to more elastic periods. Differences in price elasticity across periods may result from the combination of a fluctuating market demand and capacity or transmission constraints that bind intermitently. This hydro scheduling decision is only available to hydro producers as thermal generators are not able to "store electric power" and decide when to sell it. It is also shown that total hydro production is not a sufficient indicator of market power being exercised as hydro producers may exercise market power even when all the water available in the\reservoir is used. The real indicator of market power being exercised is the hydro scheduling strategy usedUtilities; Market Power; Scheduling of Hydro-Reservoirs.
Reaction cross sections for proton scattering from stable and unstable nuclei based on a microscopic approach
Microscopic optical model potential results for reaction cross sections of
proton elastic scattering are presented. The applications cover the 10-1000 MeV
energy range and consider both stable and unstable nuclei. The study is based
on in-medium g-matrix full-folding optical model approach with the appropriate
relativistic kinematic corrections needed for the higher energy applications.
The effective interactions are based on realistic NN potentials supplemented
with a separable non-Hermitian term to allow optimum agreement with current NN
phase-shift analyzes, particularly the inelasticities above pion production
threshold. The target ground-state densities are obtained from
Hartree-Fock-Bogoliubov calculations based on the finite range, density
dependent Gogny force. The evaluated reaction cross sections for proton
scattering are compared with measurements and their systematics is analyzed. A
simple function of the total cross sections in terms of the atomic mass number
is observed at high energies. At low energies, however, discrepancies with the
available data are observed, being more pronounced in the lighter systems.Comment: 11 pages, 4 figures, submitted to Phys. Rev.
Sensitivity of nucleon-nucleus scattering to the off-shell behavior of on-shell equivalent NN potentials
The sensitivity of nucleon-nucleus elastic scattering to the off-shell
behavior of realistic nucleon-nucleon interactions is investigated when
on-shell equivalent nucleon-nucleon potentials are used. The study is based on
applications of the full-folding optical model potential for an explicit
treatment of the off-shell behavior of the nucleon-nucleon effective
interaction. Applications were made at beam energies between 40 and 500 MeV for
proton scattering from 40Ca and 208Pb. We use the momentum-dependent Paris
potential and its local on-shell equivalent as obtained with the
Gelfand-Levitan and Marchenko inversion formalism for the two nucleon
Schroedinger equation. Full-folding calculations for nucleon-nucleus scattering
show small fluctuations in the corresponding observables. This implies that
off-shell features of the NN interaction cannot be unambiguously identified
with these processes. Inversion potentials were also constructed directly from
NN phase-shift data (SM94) in the 0-1.3 GeV energy range. Their use in
proton-nucleus scattering above 200 MeV provide a superior description of the
observables relative to those obtained from current realistic NN potentials.
Limitations and scope of our findings are presented and discussed.Comment: 17 pages tightened REVTeX, 8 .ps figures, submitted to Phys. Rev.
Modelo de cuantificación del consumo energético en edificación
The research conducted in this paper focuses on the generation
of a model for the quantification of energy consumption
in building. This is to be done through one of
the most relevant environmental impact indicators associated
with weight per m2 of construction, as well as the
energy consumption resulting from the manufacturing
process of materials used in building construction.
The practical application of the proposed model on different
buildings typologies in Seville, will provide information
regarding the building materials, the subsystems
and the most relevant construction elements. Hence, we
will be able to observe the impact the built surface has
on the environment.
The results obtained aim to reference the scientific community,
providing quantitative data comparable to other
types of buildings and geographical areas. Furthermore,
it may also allow the analysis and the characterization of
feasible solutions to reduce the environmental impact
generated by the different materials, subsystems and
construction elements commonly used in the different
building types defined in this study.La investigación realizada en el presente trabajo plantea
la generación de un modelo de cuantificación del consumo
energético en edificación, a través de uno de los indicadores
de impacto ambiental más relevantes asociados
al peso por m2 de construcción, el consumo energético
derivado del proceso de fabricación de los materiales de
construcción empleados en edificación.
La aplicación práctica del modelo propuesto sobre diferentes
tipologías edificatorias en Sevilla aportará información
respecto a los materiales de construcción, subsistemas
y elementos constructivos más impactantes,
permitiendo visualizar la influencia que presenta la superficie
construida en cuanto al impacto ambiental generado.
Los resultados obtenidos pretenden servir de referencia
a la comunidad científica, aportando datos numéricos
que podrán ser comparados en otras tipologías y ámbitos
geográficos, a la vez que permitirán analizar y precisar
mejoras en cuanto al impacto ambiental generado
por los diferentes materiales, subsistemas y elementos
constructivos habitualmente utilizados en las tipologías
edificatorias definidas
Non-Gaussian Geostatistical Modeling using (skew) t Processes
We propose a new model for regression and dependence analysis when addressing
spatial data with possibly heavy tails and an asymmetric marginal distribution.
We first propose a stationary process with marginals obtained through scale
mixing of a Gaussian process with an inverse square root process with Gamma
marginals. We then generalize this construction by considering a skew-Gaussian
process, thus obtaining a process with skew-t marginal distributions. For the
proposed (skew) process we study the second-order and geometrical
properties and in the case, we provide analytic expressions for the
bivariate distribution. In an extensive simulation study, we investigate the
use of the weighted pairwise likelihood as a method of estimation for the
process. Moreover we compare the performance of the optimal linear predictor of
the process versus the optimal Gaussian predictor. Finally, the
effectiveness of our methodology is illustrated by analyzing a georeferenced
dataset on maximum temperatures in Australi
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