A rotating molecular disk toward IRAS 18162-2048, the exciting source of HH 80-81

We present several molecular line emission arcsec and subarcsec observations obtained with the Submillimeter Array (SMA) in the direction of the massive protostar IRAS 18162-2048, the exciting source of HH 80-81. The data clearly indicates the presence of a compact (radius~425-850 AU) SO2 structure, enveloping the more compact (radius~150 AU) 1.4 millimeter dust emission (reported in a previous paper). The emission spatially coincides with the position of the prominent thermal radio jet which terminates at the HH 80-81 and HH 80N Herbig-Haro objects. Furthermore, the molecular emission is elongated in the direction perpendicular to the axis of the thermal radio jet, suggesting a disk-like structure. We derive a total dynamic mass (disk-like structure and protostar) of 11-15 msun. The SO2 spectral line data also allow us to constrain the structure temperature between 120-160 K and the volume density > 2x10^9 cm-3. We also find that such a rotating flattened system could be unstable due to gravitational disturbances. The data from C17O line emission show a dense core within this star-forming region. Additionally, the H2CO and the SO emissions appear clumpy and trace the disk-like structure, a possible interaction between a molecular core and the outflows, and in part, the cavity walls excavated by the thermal radio jet.Comment: 13 pages,11 figures. Accepted in the AJ, 07-15-201

CARMA Large Area Star Formation Survey: Observational Analysis of Filaments in the Serpens South Molecular Cloud

We present the N2H+(J=1-0) map of the Serpens South molecular cloud obtained as part of the CARMA Large Area Star Formation Survey (CLASSy). The observations cover 250 square arcminutes and fully sample structures from 3000 AU to 3 pc with a velocity resolution of 0.16 km/s, and they can be used to constrain the origin and evolution of molecular cloud filaments. The spatial distribution of the N2H+ emission is characterized by long filaments that resemble those observed in the dust continuum emission by Herschel. However, the gas filaments are typically narrower such that, in some cases, two or three quasi-parallel N2H+ filaments comprise a single observed dust continuum filament. The difference between the dust and gas filament widths casts doubt on Herschel ability to resolve the Serpens South filaments. Some molecular filaments show velocity gradients along their major axis, and two are characterized by a steep velocity gradient in the direction perpendicular to the filament axis. The observed velocity gradient along one of these filaments was previously postulated as evidence for mass infall toward the central cluster, but these kind of gradients can be interpreted as projection of large-scale turbulence.Comment: 12 pages, 4 figures, published in ApJL (July 2014

Performance characterization of a PCM storage tank

This paper presents the experimental results of a versatile latent heat storage tank capable of working with organic phase-change materials within a temperature range from -10 °C to 100 °C. The tank contains a paraffin with a phase-change temperature between 3 °C and 8 °C. Firstly, this study focuses on explaining the design criteria which were followed to build the tank. Secondly, a full experimental characterization of the performance has been carried out. The enthalpy temperature curve, the specific heat and density have been measured for the tested paraffin. The performance of the tank has been analyzed in terms of the vertical stratification within the PCM, the effectiveness, the reacted fraction and the total heat transfer of the tank. The results indicate that up to 78% of the maximum capacity is reached within 4 h. The performance is mainly controlled by the supply temperature and the effect of the mass flow rate is almost negligible given that all the tests are in laminar flow.The authors from the Polytechnic University of Valencia gratefully acknowledge ACCIONA Infraestructuras for the funding of the LHTS installation. The authors from University of Zaragoza would like to thank the Spanish Government for the partial funding of this work within the framework of research projects ENE2008-06687-C02-02 and ENE2011-28269-C03-01.López Navarro, A.; Biosca Taronger, J.; Corberán Salvador, JM.; Peñalosa, C.; Lázaro, A.; Dolado, P.; Payá Herrero, J. (2014). Performance characterization of a PCM storage tank. Applied Energy. 119:151-162. doi:10.1016/j.apenergy.2013.12.041S15116211

Infrared and optical polarimetry around the low-mass star-forming region NGC 1333 IRAS 4A

We performed J- and R-band linear polarimetry with the 4.2 m William Herschel Telescope at the Observatorio del Roque de los Muchachos and with the 1.6 m telescope at the Observat\'orio do Pico dos Dias, respectively, to derive the magnetic field geometry of the diffuse molecular cloud surrounding the embedded protostellar system NGC 1333 IRAS 4A. We obtained interstellar polarization data for about two dozen stars. The distribution of polarization position angles has low dispersion and suggests the existence of an ordered magnetic field component at physical scales larger than the protostar. Some of the observed stars present intrinsic polarization and evidence of being young stellar objects. The estimated mean orientation of the interstellar magnetic field as derived from these data is almost perpendicular to the main direction of the magnetic field associated with the dense molecular envelope around IRAS 4A. Since the distribution of the CO emission in NGC 1333 indicates that the diffuse molecular gas has a multi-layered structure, we suggest that the observed polarization position angles are caused by the superposed projection along the line of sight of different magnetic field components.Comment: 37 pages, 9 figures, 5 tables, accepted for publication in A

CARMA Large Area Star Formation Survey: Project Overview with Analysis of Dense Gas Structure and Kinematics in Barnard 1

We present details of the CARMA Large Area Star Formation Survey (CLASSy), while focusing on observations of Barnard 1. CLASSy is a CARMA Key Project that spectrally imaged N2H+, HCO+, and HCN (J=1-0 transitions) across over 800 square arcminutes of the Perseus and Serpens Molecular Clouds. The observations have angular resolution near 7" and spectral resolution near 0.16 km/s. We imaged ~150 square arcminutes of Barnard 1, focusing on the main core, and the B1 Ridge and clumps to its southwest. N2H+ shows the strongest emission, with morphology similar to cool dust in the region, while HCO+ and HCN trace several molecular outflows from a collection of protostars in the main core. We identify a range of kinematic complexity, with N2H+ velocity dispersions ranging from ~0.05-0.50 km/s across the field. Simultaneous continuum mapping at 3 mm reveals six compact object detections, three of which are new detections. A new non-binary dendrogram algorithm is used to analyze dense gas structures in the N2H+ position-position-velocity (PPV) cube. The projected sizes of dendrogram-identified structures range from about 0.01-0.34 pc. Size-linewidth relations using those structures show that non-thermal line-of-sight velocity dispersion varies weakly with projected size, while rms variation in the centroid velocity rises steeply with projected size. Comparing these relations, we propose that all dense gas structures in Barnard 1 have comparable depths into the sky, around 0.1-0.2 pc; this suggests that over-dense, parsec-scale regions within molecular clouds are better described as flattened structures rather than spherical collections of gas. Science-ready PPV cubes for Barnard 1 molecular emission are available for download.Comment: Accepted to The Astrophysical Journal (ApJ), 51 pages, 27 figures (some with reduced resolution in this preprint); Project website is at http://carma.astro.umd.edu/class

Arquitectura genérica de una red en chip de enrutamiento unidireccional en FPGA

El constante aumento de los componentes que contiene un sistema on-chip ha incrementado la complejidad de comunicación entre los elementos de procesamiento (EPs) del sistema. Un recurso utilizado para disminuir la complejidad es el diseño de enrutamiento de conexiones (cableado), el cual ha sido suficiente para interconectar algunos EPs, dicho diseño se conoce como redes en chip o por sus siglas en inglés NoC (Network on Chip), de manera alternativa, enrutar paquetes permite una mayor escalabilidad de las redes, tener una latencia aceptable y una utilización moderada de área. Sin embargo, las redes en chip (NoC) suelen ser implementadas en tecnologías rígidas y deterministas como los ASIC (Circuito Integrado de Aplicación Específica), limitando la flexibilidad, arquitectura y modularidad que ofrece una NoC de enrutamiento de paquetes. Este trabajo propone una arquitectura de una red en chip de switcheo o enrutamiento unidireccional utilizando un router genérico para topología de mariposa, de enrutamiento de paquetes, implementado en una FPGA de la familia Xilinx. Donde el diseño permite enviar paquetes desde 16 puntos de origen, hacia 16 puntos de destino, así como la flexibilidad de enviar paquetes de diferentes tamaños, divididos enflits. Este diseño tiene como resultado una arquitectura compacta, permitiendo dejar el mayor espacio posible para los EPs.Palabra(s) Clave(s): arquitectura de router, control de flujo, FPGA, NoC, redes en chip

Influencia del proceso de elaboración en el deterioro y conservación de materiales cerámicos: ejemplo en el Antiguo Hospital de Jornaleros de Maudes, Madrid (España)

Consejo Superior de Investigaciones Científicas (CSIC-UCM)Comunidad de MadridUnión europea. Fondo Social Europeo. El Fondo Social Europeo invierte en tu futuro.Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Twisted Tensor Products of Kn with Km

We find three families of twisting maps of Km with Kn, where K is a field, and we make a detailed study of its properties. One of them is related to truncated quiver algebras, the second one consists of deformations of the first and the third one requires m = n and yields algebras isomorphic to Mn(K).Fil: Arce, Jack. Pontificia Universidad Católica del Perú. Sección Matemáticas; PerúFil: Guccione, Jorge Alberto. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Investigaciones Matemáticas "Luis A. Santaló". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Matemáticas "Luis A. Santaló"; ArgentinaFil: Guccione, Juan Jose. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Valqui, Christian. Pontificia Universidad Católica del Perú. Sección Matemáticas; Perú. Instituto de Matemática y Ciencias Afines; Per

Handmade clay bricks: chemical, physical and mechanical properties

The clay brick masonry that is much used in historical structures often is in a rather poor state of conservation. In order to intervene correctly in these buildings, it is convenient to characterize the old material. For this purpose, a large sample of clay brick specimens from the 12th to 19th century were collected from six Portuguese monasteries, and were characterized chemically, physically and mechanically. A large variability of the properties was found. Additionally, a sample of handmade new bricks, which are commonly used as replacing material, was also analysed. The results were compared to the old bricks and could be possibly adequate as substitution bricks. Still, significant differences were found in chemical composition, and in water absorption and porosity, which are much lower in modern handmade bricks. With respect to mechanical properties, the range of values found in old bricks was rather high and the degree of deterioration exhibited a large scatter, meaning that a conclusion is hardly possible.The authors gratefully acknowledge the Instituto de Gestao do Patrimonio Arquitectonico e Arqueologico (IGESPAR) for providing the old clay bricks used in the present work. The first author acknowledges the partial funding of this work by the FCT through the following scholarships POCTI SFRH/BD/6409/2001 and POCTI SFRH/BPD/26706/2005