819 research outputs found
Fourth virial coefficients of asymmetric nonadditive hard-disc mixtures
The fourth virial coefficient of asymmetric nonadditive binary mixtures of
hard disks is computed with a standard Monte Carlo method. Wide ranges of size
ratio () and nonadditivity () are
covered. A comparison is made between the numerical results and those that
follow from some theoretical developments. The possible use of these data in
the derivation of new equations of state for these mixtures is illustrated by
considering a rescaled virial expansion truncated to fourth order. The
numerical results obtained using this equation of state are compared with Monte
Carlo simulation data in the case of a size ratio and two
nonadditivities .Comment: 9 pages, 7 figures; v2: section on equation of state added; tables
moved to supplementary material
(http://jcp.aip.org/resource/1/jcpsa6/v136/i18/p184505_s1#artObjSF
Los Papiros de Herculano en la España de finales del siglo XVIII y comienzos del XIX
The aim of this article is to explore the interest aroused by the Herculaneum papyri among Spanish intellectuals in the 18th and 19th centuries. For this purpose, the authors draw on the testimony of travellers, scholars and prominent writers like Francisco Pérez Báyer, Nicolás de Azara, Esteban de Arteaga, Leandro Fernández de Moratín, Pedro Antonio de Alarcón, Pedro Montengón and Juan Andrés y Morell. While the first five writers reflect upon the topic in a general manner, Montegón and Andrés do deal with it in greater detail
Experiencies in obtaining polymeric composites reinforced with natural fiber from Ecuador
Esta revisión presenta los reportes de las investigaciones
relacionadas con el desarrollo de nuevos materiales
compuestos poliméricos reforzados con fibras
naturales y desechos agroindustriales provenientes del
Ecuador. Se analizan las fibras vegetales con potencial
para ser empleadas como reforzante en compuestos
poliméricos. Se sintetizan los resultados relevantes
de las diferentes investigaciones analizadas. Aspectos
como el tipo de matriz, la morfología de las fibras, los
tratamientos superficiales y las propiedades mecánicas
son presentados.This review presents the research reports related to
the development of new polymeric composites reinforced
with natural fibers and agro-industrial wastes
from Ecuador. Vegetable fibers with potential are
analyzed to be used as reinforcement in polymeric
composites. It summarizes the relevant results from
the different investigations analyzed. Aspects such
as the type of matrix, the fiber morphology, surface
treatment and mechanical properties are presented
Reparación del cartílago articular con injerto libre de pericondrio estudio experimental
Ante la incapacidad de regeneración espontánea de lesiones profundas y amplias
del cartílago articular, estudiamos la reparación cartilaginosa con plastias de pericondrio
tomadas de la región condro-costal e implantándolas con su cara condrogénica sobre una lesión
osteocondral realizada en la superficie articular rotuliana. Macroscópica e histológicamente,
a la octava semana, el neocartílago formado tenía igual apariencia que el cartílago hialino
normal, no existiendo separación entre el cartílago remanente y el neoformado a partir de la
plastia. Estos resultados corroboran el gran potencial condrogénico del pericondrioFaced with the incapacity of spontaneous regeneration of deep and extensive
lesions of the articular cartilage we studied the cartilaginous repair with pericondrium grafts taken
from the chondro-costal region. Grafts were implanted with their condrogenic face over an
osteochondral defect located at the surface of the patella. At the 8th week, the neocartilage formed
had macroscopically and histologically, the same appearance as the normal hyaline cartilage,
with no separation between the remaining cartilage and the neocartilage induced by the
graft. These results corroborate the high chondrogenic potential of the perichondrium
Virial series for fluids of hard hyperspheres in odd dimensions
A recently derived method [R. D. Rohrmann and A. Santos, Phys. Rev. E. {\bf
76}, 051202 (2007)] to obtain the exact solution of the Percus-Yevick equation
for a fluid of hard spheres in (odd) dimensions is used to investigate the
convergence properties of the resulting virial series. This is done both for
the virial and compressibility routes, in which the virial coefficients
are expressed in terms of the solution of a set of coupled algebraic
equations which become nonlinear for . Results have been derived up
to . A confirmation of the alternating character of the series for , due to the existence of a branch point on the negative real axis, is found
and the radius of convergence is explicitly determined for each dimension. The
resulting scaled density per dimension , where is the
packing fraction, is wholly consistent with the limiting value of 1 for . Finally, the values for predicted by the virial and
compressibility routes in the Percus-Yevick approximation are compared with the
known exact values [N. Clisby and B. M. McCoy, J. Stat. Phys. {\bf 122}, 15
(2006)]Comment: 9 pages, 6 figure
Structural and magnetic properties of Ni0.8Fe0.2/Ti nanoscale multilayers
The influence of the thickness of the Ni0.8Fe0.2 (Permalloy, Py) layers on the structural and magnetic properties of magnetron sputtered Py/Ti multilayers was studied. The thickness of the Py layers was varied in the interval of 8 to 30 Å. X-ray reflectivity scans evidence the existence of a well-defined layered structure in all the samples considered, but also the presence of a complex intermixed interface. The shape of both the temperature dependence of magnetization and the hysteresis loops of the multilayered structures depends strongly on Py thickness. Magnetic and reflectivity measurements were comparatively analyzed in order to better understand the structure of the samples, and specifically, their interfaces. In particular, the presence of small superparamagnetic Py at the interfaces of the samples, especially evident in the samples with the thinnest Py layers, seems confirmed by the magnetic measurements, agreeing well with the reflectivity results. © 2018 by the authors.1 Instituto Regional de Investigación Científica Aplicada (IRICA) and Departamento de Física Aplicada, Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain; [email protected] (J.A.G.); [email protected] (J.P.A.) 2 Department of Solid State Magnetism, Institute of Natural Sciences and Mathematics, Ural Federal University, 620002 Ekaterinburg, Russia; [email protected] (A.V.S.); [email protected] (G.V.K.) 3 Departamento de Electricidad y Electrónica, Universidad del País Vasco (UPV/EHU), 48080 Bilbao, SpainFunding: The research was supported by the Ministry of Education and Science of the Russian Federation (Agreement no. 02.A03.21.0006) and by the Spanish projects MAT2014-58034-R (MINECO/AEI/FEDER, EU) and PEII-2014-042-P (JCCM/FEDER, EU)
Modeling the acquisition front-end in high resolution gamma-ray imaging
The availability of synthetic realistic data eases design optimization, algorithm evaluation and verification of any digital system where a significant amount of digital signal processing is performed. The evolution of positron emission tomography cameras towards continuous sampling of individual position-sensitive photomultiplier anodes with processing algorithms implemented on digital programmable logic devices creates a new framework where new approaches to the γ-event detection are possible. We have developed a system model of the acquisition chain, including multi-layer phoswich, photomultiplier, front-end analog electronics, data acquisition and digital processing. This processing includes estimation algorithms for the most relevant event parameters: energy, layer-of-interaction, time picking-off and event location. The selected simulation platform couples gently to digital hardware simulation tools, in such a way that implemented models may generate real-like stimuli for the digital system under development. The modeling of the whole front-end electronics enables deeper understanding and tuning of different system trade-offs and provides a rapid and soft transition between specification and hardware developmentPublicad
La Villa de los Papiros de Herculano en el siglo XXI: actualización científica y estado de la cuestión (2000-2016)
Nuestro propósito es valorar qué aporta al Humanismo el legado que, oculto durante veinte siglos, apareció en uno de los recintos arqueológicos más interesantes que se conocen en la actualidad, la Villa de los Papiros de Herculano, sepultada por la lava del Vesubio en el año 79 d.C. A partir de 1750, empezó a ser excavada, lo que permitió que se descubriera una lujosa mansión que, además de otras piezas de gran valor, contenía la única biblioteca que ha llegado hasta nosotros desde la Antigüedad. Estos fondos están constituidos por casi dos mil rollos de papiro escritos en griego y atribuidos a un autor oriundo de Siria llamado Filodemo de Gádara. Hace XXI siglos, congregó a los simpatizantes de una escuela cuyo objetivo fundamental era búsqueda de la felicidad. Estamos convencidos de que el mensaje de alegría de vivir, serenidad y tolerancia de Epicuro está más vivo que nunca. Nuestro fin es poner al alcance de un buen número de personas, no sólo de los interesados en el pensamiento, la literatura, la historia y la arqueología helenística e imperial, sino de cualquier persona culta con inquietudes humanísticas todo este rico y complejo legado.Our purpose is to assess the contribution to the Humanism of the legacy hidden for twenty centuries and appeared in one of the most interesting archaeological sites that we know now, the Villa dei Papiri at Herculaneum, buried by lava from Vesuvius in 79 AD. Since 1750, it began to be excavated and it has allowed us to discover a luxurious mansion, great value articles and the only library that has come down to us from Antiquity. This content is made up by almost two thousand rolls of papyrus written in Greek and attributed to an author born in Gadara –Syria- called Philodemus. Twenty centuries ago it brought together the followers of the school, whose main objective was the pursuit of happiness. We are convinced that the message of serenity, zest for life and tolerance of Epicurus is more alive than ever. Our aim is to make available to a great number of people, not just to those interested in Philosophy, Literature, History and Archeology of Hellenistic and Imperial Periods, but also any educated person with humanistic concerns this rich and complex legacy
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