1,383 research outputs found
Aplicación del modelo modergis en el uso sostenible en la dendroenergía y los biocombustibles para países en vía de desarrollo- caso Colombia.
Numerosos países en vía de desarrollo caso Colombia, contienen un enorme potencial de recursos en energías
renovables como la dendroenergía incluidos los biocombustibles, pero no se utilizan en gran magnitud ni se
han incorporado al Mix Energético Nacional debido a la falta de herramientas que las evalué e integre de
manera armónico y con criterio sostenible. En tal sentido la Universidad Nacional de Colombia y el Centro de
Investigaciones Energéticas Medioambientales y Tecnológicas - CIEMAT de España, han desarrollado
conjuntamente una herramienta de planificación energética sostenible denominada - MODERGIS - que tiene
como objeto la incorporación, evaluación y análisis de energías renovables con énfasis a la dendroenergía y los
biocombustibles utilizando las técnicas de los Sistemas de Información Geográfica - SIG, como instrumento
alternativo de planificación y uso sostenible ambiental, social, económico y cultural del uso del suelo. El
modelo esta conformado por tres componentes: ENERDEM modelo de demanda- oferta de energía, ENERSIG:
espacialización e integración de energías renovables mediante los Sistemas de Información Geográfica - SIG
y ENERSOS modelo basado en métodos de análisis multiobjetivo tendientes a optimizar las dimensiones de la
sostenibilidad de las fuentes energética, incorporando el análisis de ciclo de vida.
Los resultados preliminares del modelo presentan 6.8 Millones de hectáreas factibles en el uso de la
Dendroenergía, el cual significaría un potencial de 4400 MW instalables si se dedicara en la producción de
energía eléctrica. En biocombustibles el Biodiesel de palma de aceite arroja un potencial de 1017 millones de
barriles y 54 millones de barriles de etanol de caña de azúcar, el cual justificaría proporciones de
abastecimiento interno con las mezclas de E10 y B5, quedando un gran potencial para interferir el mercado
internacional, lo cual con la metodología de ModerGIS tiene incluido los criterios de sostenibilidad que son
necesarios para ingresar a estos mercados.An essential element to reach sustainable development is an appropriate and reliable energy supply. This
helps to eradicate poverty, improve human welfare, and to raise quality of life in the population. However, many
regions in the world do not have a reliable supply, and its use exceeds economic limits, creating a dichotomy
between growth and sustainability. World institutons such as United Nations and its organization UNESCO,
have demonstrated that current energy production and consumption models are not sustainable in a medium
term.
Many countries, especially those that are in development such as Colombia, have a great potential of
renewable energy resources that have not been used or incorporated into the energy mix due to the lack of
tools to evaluate and to integrate them with a sustainability criteria. Then, “Universidad Nacional de Colombia”
(Colombia) and “Centro de Investigaciones Energéticas Medioambientales y Tecnológicas – CIEMAT” (Spain)
have jointly developed an integrated energy planning tool named MODERGIS. Its objective is to incorporate,
evaluate and analyze renewable resources such as wood energy including biofuels. This model comprises
three constitutive elements: an energy supply-demand model (ENERDEM), an integration and space definition
of renewable energy through geographic information systems (ENERSIG), and a multi-objectiveanalysis to
optimize sustainability dimensions of energy sources (ENERSOS).
The current paper shows some of the preliminary results of this model, and discusses on the methodological
issues faced during its development. Further and more expanded results are expected to be published in the
near future
Null Fields Realizations of from and Algebras
We consider the nonlinear algebras and
and find their realizations in terms of currents spanning conformal linearizing
algebras. The specific structure of these algebras, allows us to construct
realizations modulo null fields of the algebra that lies in the cosets
and . Such realizations exist for
the following values of the algebra central charge:
. The first two values are listed for the first time,
whereas for the remaining values we get the new realizations in terms of an
arbitrary stress tensor and affine currents.Comment: Submitted to Phys. Lett. B; PACS-no 11.30.L
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A case of atypical disseminated herpes simplex virus 1 with hepatitis in a liver transplant recipient: the need for dermatologic evaluation
Disseminated herpes simplex virus (HSV) is mainly seen in immunocompromised individuals. Atypical lesions can be present in both primary infection and reactivation disease. Compared with the general population, inmunocompromised hosts are at greater risk of increased persistency and severity of clinical manifestations, including severe systemic involvement such as esophagitis, meningitis, and hepatitis. Herein, we report the case of a liver transplant recipient with atypical disseminated herpes simplex virus-1 complicated by HSV-related hepatitis. Dermatological consultation and histological assessment were crucial for a correct diagnosis and treatment
The W(sl(N+3),sl(3)) algebras and their contractions to W3
We construct the nonlinear algebras and find the spectrum
of values of the central charge that gives rise, by contracting the
algebras, to a algebra belonging to the coset
. Part of the spectrum was conjectured
before, but part of it is given here for the first time. Using the tool of
embedding the algebras into linearizing algebras, we
construct new realizations of modulo null fields. The possibility to
predict, within the conformal linearization framework, the central charge
spectrum for minimal models of the nonlinear algebras is
discussed at the end.Comment: 12 pages, 2 tables, LaTeX, minor typos corrected on pages 4 and
Variable Intrinsic Absorption in Mrk 279
We examine the variability in the intrinsic absorption in the Seyfert 1
galaxy Mrk 279 using three epochs of observations from the Far Ultraviolet
Spectroscopic Explorer (FUSE) and two epochs of observations with the Space
Telescope Imaging Spectrograph on the Hubble Space Telescope. Rather than
finding simple photoionization responses of the absorbing gas to changes in the
underlying continuum, the observed changes in the absorption profiles can be
understood more clearly if the effective covering fraction of the gas in all
emission components, continuum and broad and intermediate velocity width
emission lines, is accounted for. While we do not uniquely solve for all of
these separate covering fractions and the ionic column densities using the
spectral data, we examine the parameter space using previously well-constrained
solutions for continuum and single emission component covering fractions.
Assuming full coverage of the continuum, we find that of the two velocity
components of the Mrk 279 absorption most likely associated with its outflow,
one likely has zero coverage of the intermediate line region while the other
does not. For each component, however, the broad line region is more fully
covered than the intermediate line region. Changes in the O VI column densities
are unconstrained due to saturation, but we show that small changes in the
nonsaturated C IV and N V column densities are consistent with the outflow gas
having zero or partial covering of the intermediate line region and an
ionization parameter changing from ~0.01 to ~0.1 from 2002 to 2003 as the UV
continuum flux increased by a factor of ~8. The absence of a change in the C
III absorbing column density is attributed to this species arising outside the
Mrk 279 outflow.Comment: 36 pages, 18 figures, accepted to Ap
Optimization of multichip RFID tag antenna with genetic algorithm and method of moments
A specific procedure is implemented for the optimization of passive part of multichip RFID tag antenna, based on the performance parameter in terms of newly developed concepts. Examples are given and significant improvements have been observed comparing with previous results, which verifies the approach
Intrinsic Absorption in the Spectrum of NGC 7469: Simultaneous Chandra, FUSE, and STIS Observations
We present simultaneous X-ray, far-ultraviolet, and near-ultraviolet spectra
of the Seyfert 1 galaxy NGC 7469 obtained with the Chandra X-Ray Observatory,
the Far Ultraviolet Spectroscopic Explorer, and the Space Telescope Imaging
Spectrograph on the Hubble Space Telescope. Previous non-simultaneous
observations of this galaxy found two distinct UV absorption components, at
-560 and -1900 km/s, with the former as the likely counterpart of the X-ray
absorber. We confirm these two absorption components in our new UV
observations, in which we detect prominent O VI, Ly alpha, N V, and C IV
absorption. In our Chandra spectrum we detect O VIII emission, but no
significant O VIII or O VII absorption. We also detect a prominent Fe K alpha
emission line in the Chandra spectrum, as well as absorption due to
hydrogen-like and helium-like neon, magnesium, and silicon at velocities
consistent with the -560 km/s UV absorber. The FUSE and STIS data reveal that
the H I and C IV column densities in this UV- and X-ray- absorbing component
have increased over time, as the UV continuum flux decreased. We use measured H
I, N V, C IV, and O VI column densities to model the photoionization state of
both absorbers self-consistently. We confirm the general physical picture of
the outflow in which the low velocity component is a highly ionized, high
density absorber with a total column density of 10^20 cm^-2, located near the
broad emission line region, although due to measurable columns of N V and C IV,
we assign it a somewhat smaller ionization parameter than found previously,
U~1. The high velocity UV component is of lower density, log N=18.6, and likely
resides farther from the central engine as we find its ionization parameter to
be U=0.08.Comment: Minor correction to abstract; STScI eprint #1683; 50 pages, incl. 19
figures, 4 tables; Accepted to Ap
Images and Spectral Performance of WFC3 Interference Filters
The Wide Field Camera 3 (WFC3) is a panchromatic imager that will be deployed in the Hubble Space Telescope (HST). The mission of the WFC3 is to enhance HST1s imaging capability in the ultraviolet, visible and near-infrared spectral regions. Together with a wavelength coverage spanning 2000A to 1.7 micron, the WFC3 high sensitivity, high spatial resolution, and large field-of-view provide the astronomer with an unprecedented set of tools for exploring all types of exciting astrophysical terrain and for addressing many key questions in astronomy today. The filter compliment, which includes broad, medium, and narrow band filters, naturally reflects the diversity of astronomical programs to be targeted with WFC3. The WFC3 holds 61 UVIS filters elements, 14 IR filters, and 3 dispersive elements. During ground testing, the majority of the UVIS filters were found to exhibit excellent performance consistent with or exceeding expectations; however, a subset of filters showed considerable ghost images; some with relative intensity as high as 10-15%. Replacement filters with band-defining coatings that substantially reduce these ghost images were designed and procured. A state-of-the-art characterization setup was developed to measured the intensity of ghost images, focal shift, wedge direction , transmitted uniformity and surface feature of filters that could effect uniform flat field images. We will report on this new filter characterization methods, as well as the spectral performance measurements of the in-band transmittance and blocking
FTIR-ATR Spectroscopy Combined with Multivariate Regression Modeling as a Preliminary Approach for Carotenoids Determination in Cucurbita spp
Quantitative analysis of carotenoids has been extensively reported using UV\u2010Vis
spectrophotometry and chromatography, instrumental techniques that require complex extraction
protocols with organic solvents. Fourier transform infrared spectroscopy (FTIR) is a potential
alternative for simplifying the analysis of food constituents. In this work, the application of FTIR
with attenuated total reflectance (ATR) was evaluated for the determination of total carotenoid
content (TCC) in Cucurbita spp. samples. Sixty\u2010three samples, belonging to different cultivars of
butternut squash (C. moschata) and pumpkin (C. maxima), were selected and analyzed with
FTIR\u2010 ATR (attenuated total reflectance). Three different preparation protocols for samples were
followed: homogenization (A), freeze\u2010drying (B), and solvent extraction (C). The recorded spectra
were used to develop regression models by Partial Least Squares (PLS), using data from TCC,
determined by UV\u2010Vis spectrophotometry. The PLS regression model obtained with the FTIR data
from the freeze\u2010dried samples, using the spectral range 920\u20133000 cm 121, had the best figures of merit
(R2CAL of 0.95, R2PRED of 0.93 and RPD of 3.78), being reliable for future application in agriculture. This
approach for carotenoid determination in pumpkin and squash avoids the use of organic solvents.
Moreover, these results are a rationale for further exploring this technique for the assessment of
specific carotenoids in food matrices
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