40,433 research outputs found
Second-generation bioethanol from industrial wood waste of South American species
There is a global interest in replacing fossil fuels with renewable sources of energy. The present review evaluates the significance of South-American wood industrial wastes for bioethanol production. Four countries have been chosen for this review, i.e., Argentina, Brazil, Chile, and Uruguay, based on their current or potential forestry industry. It should be noted that although Brazil has a global bioethanol market share of 25%, its production is mainly first-generation bioethanol from sugarcane. The situation in the other countries is even worse, in spite of the fact that they have regulatory frameworks in place already allowing the substitution of a percentage of gasoline by ethanol. Pines and eucalyptus are the usually forested plants in these countries, and their industrial wastes, as chips and sawdust, could serve as promising raw materials to produce second-generation bioethanol in the context of a forest biorefinery. The process to convert woody biomass involves three stages: pretreatment, enzymatic saccharification, and fermentation. The operational conditions of the pretreatment method used are generally defined according to the physical and chemical characteristics of the raw materials and subsequently determine the characteristics of the treated substrates. This article also reviews and discusses the available pretreatment technologies for eucalyptus and pines applicable to South-American industrial wood wastes, their enzymatic hydrolysis yields, and the feasibility of implementing such processes in the mentioned countries in the frame of a biorefinery.Fil: Vallejos, MarĂa Evangelina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas QuĂmicas y Naturales. Instituto de Materiales de Misiones; ArgentinaFil: Kruyeniski, Julia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas QuĂmicas y Naturales. Instituto de Materiales de Misiones; ArgentinaFil: Area, Maria Cristina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas QuĂmicas y Naturales. Instituto de Materiales de Misiones; Argentin
Cognitive Approaches to Phenomenal Consciousness
The most promising approaches to understanding phenomenal consciousness are what I’ll call cognitive approaches, the most notable exemplars of which are the theories of consciousness articulated by David Rosenthal and Daniel Dennett. The aim of the present contribution is to review the core similarities and differences of these exemplars, as well as to outline the main strengths and remaining challenges to this general sort of approach
Results from the Commissioning of the ATLAS Pixel Detector with Cosmic data
The ATLAS pixel detector is the innermost detector of the ATLAS experiment at
the Large Hadron Collider at CERN. With approximately 80 million readout
channels, the ATLAS silicon pixel detector is a high-acceptance,
high-resolution, low-noise tracking device. Providing the desired refinement in
charged track pattern recognition capability in order to meet the stringent
track reconstruction requirements, the pixel detector largely defines the
ability of ATLAS to effectively resolve primary and secondary vertices and
perform efficient flavor tagging essential for discovery of new physics.
Being the last sub-system installed in ATLAS by July 2007, the pixel detector
was successfully connected, commissioned, and tested in situ while meeting an
extremely tight schedule, and was ready to take data upon the projected turn-on
of the LHC. Since fall 2008, the pixel detector has been included in the
combined ATLAS detector operation, collecting cosmic muon data. Details from
the pixel detector installation and commissioning, as well as details on
calibration procedures and the results obtained with collected cosmic data, are
presented along with a summary of the detector status.Comment: To be published in the proceedings of DPF-2009, Detroit, MI, July
2009, eConf C090726. Contents: 9 pages, 13 figures, 9 reference
HST Imaging in the Chandra Deep Field South: II. WFPC2 Observations of an X-Ray Flux-Limited Sample from the 1 Msec Chandra Catalog
We present HST/WFPC2 observations of a well-defined sample of 40 X-ray
sources with X-ray fluxes above the detection threshold of the full 1 Msec
Chandra Deep Field South (CDFS). The sensitivity and spatial resolution of our
HST observations are sufficient to detect the optical counterparts of 37 of the
X-ray sources, yielding information on their morphologies and environments. In
this paper we extend the results obtained in our previous study on the 300 ks
CDFS X-ray data (Schreier et al. 2001, Paper I). Specifically, we show that the
optical counterparts to the X-ray sources are divided into two distinct
populations: 1) an optically faint group with relatively blue colors, similar
to the faint blue field galaxy population, and 2) an optically brighter group,
including resolved galaxies with average colors significantly redder than the
corresponding bright field galaxy population. The brighter objects comprise a
wide range of types, including early and late type galaxies, starbursts, and
AGN. By contrast, we show that the faint blue X-ray population are most
consistent with being predominantly Type 2 AGN of low to moderate luminosity,
located at higher redshifts (z ~ 1 - 2). This conclusion is supported by
luminosity function models of the various classes of objects. Hence, the
combination of deep X-ray data with the high spatial resolution of HST are for
the first time allowing us to probe the faint end of the AGN luminosity
function at cosmologically interesting redshifts.Comment: AASTEX-Latex, 25 pages, 4 postscript figures, 9 jpg figures. Accepted
by the Astrophysical Journal. Full-size postscript images and figures,
included in the preprint, are available from:
http://www.stsci.edu/~koekemoe/papers/cdfs-hst
Potential Food and Nonfood Utilization of Potatoes and Related Byproducts in North Dakota
Demand and Price Analysis,
The "UV-route" to search for Blue Straggler Stars in Globular Clusters: first results from the HST UV Legacy Survey
We used data from the HST UV Legacy Survey of Galactic Globular Clusters to
select the Blue Straggler Star (BSS) population in four intermediate/high
density systems (namely NGC 2808, NGC 6388, NGC 6541 and NGC 7078) through a
"UV-guided search". This procedure consists in using the F275W images in each
cluster to construct the master list of detected sources, and then force it to
the images acquired in the other filters. Such an approach optimizes the
detection of relatively hot stars and allows the detection of complete sample
of BSSs even in the central region of high-density clusters, because the light
from the bright cool giants, which dominates the optical emission in old
stellar systems, is sensibly reduced at UV wavelengths. Our UV-guided
selections of BSSs have been compared to the samples obtained in previous,
optical-driven surveys, clearly demonstrating the efficiency of the UV
approach. In each cluster we also measured the parameter A+, defined as the
area enclosed between the cumulative radial distribution of BSSs and that of a
reference population, which traces the level of BSS central segregation and the
level of dynamical evolution suffered by the system. The values measured for
the four clusters studied in this paper nicely fall along the dynamical
sequence recently presented for a sample of 25 clusters.Comment: 30 pages, 9 figures, 4 tables; accepted for publication in Ap
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