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Search Results: 1 - 10 of 189972 matches for " G. Anglada "
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VLA observations of disks and jets in young close binaries
G. Anglada
Revista mexicana de astronomía y astrofísica , 2004,
Abstract: Presentamos resultados observacionales de alta resoluci on angular de las fuentes SVS 13, NGC1333 VLA2 y L723 VLA2 obtenidos con el VLA. Nuestros resultados indican que estas fuentes son sistemas binarios compactos (con una separaci on de 25-75 AU) y muy j ovenes, y sugieren que el proceso de desarrollo de discos y chorros puede ocurrir de modo distinto para cada componente del sistema binario.
Influencia de la fase sigma en la laminación en frío de los aceros inoxidables dúplex
Fargas, G.,Mateo, A.,Anglada, M.
Boletín de la Sociedad Espa?ola de Cerámica y Vidrio , 2004,
Abstract: One of the steps in the industrial rolling process of duplex stainless steels is the annealing heat treatment after hot rolling. If this annealing is performed in a temperature range that favours the precipitation of intermetallic phases, the mechanical properties can be modified considerably. The formation of these precipitates has a detrimental effect on the DSS ductility and toughness, so it will be a drawback for further cold rolling. In the present investigation, the effect of the sigma phase during cold rolling of a duplex stainless steel type EN 1.4462 has been studied. To simulate this process, compression tests up to a thickness reduction similar to that performed at industrial level have been done. The testing samples were studied by optical microscopy, SEM (scanning electronic microscopy) and TEM (transmission electronic microscopy). Afterwards, some of the annealing conditions were selected in order to carry out cold rolling, using a laboratory scale machine, with the aim to observe if they offered a similar behaviour as that experienced in the compression tests. The results show that only the annealing condition at 975oC during 10 minutes allows to produce sheets without rolling defects. Una de las etapas en el proceso de fabricación industrial de los aceros inoxidables dúplex laminados es el tratamiento térmico de recocido posterior a la laminación en caliente. Si dicho recocido se efectúa en un rango de temperaturas que favorezca la formación de fases intermetálicas, las propiedades mecánicas del material pueden modificarse notablemente. La presencia en la microestructura bifásica de dichos precipitados provoca efectos muy perjudiciales sobre la ductilidad y la tenacidad del material, pudiendo llegar a hacer inviable la posterior etapa de laminación en frío. En el presente trabajo se ha estudiado el efecto sobre el proceso de laminación en frío de la presencia de fase sigma en un acero dúplex tipo E.N. 1.4462. Para simular dicho proceso se han realizado ensayos de compresión sobre probetas con diferentes porcentajes de fase sigma aplicando reducciones de espesor similares a las desarrolladas en la industria. Las probetas ensayadas fueron estudiadas por microscopía óptica, MEB (microscopía electrónica de barrido) y por MET (microscopía electrónica de transmisión). Posteriormente se laminaron a escala de laboratorio algunos de los aceros tratados térmicamente con el fin de corroborar si ofrecían un comportamiento similar al de los ensayos de compresión. Los resultados obtenidos muestran que únicamente el recocido a 975oC durante 10 minutos
Perspective acceleration and gravitational redshift. Measuring masses of individual white dwarfs using Gaia + SIM astrometry
G. Anglada-Escude,J. H. Debes
Physics , 2009, DOI: 10.1017/S1743921309990627
Abstract: According to current plans, the SIM/NASA mission will be launched just after the end of operations for the Gaia/ESA mission. This is a new situation which enables long term astrometric projects that could not be achieved by either mission alone. Using the well-known perspective acceleration effect on astrometric measurements, the true heliocentric radial velocity of a nearby star can be measured with great precision if the time baseline of the astrometric measurements is long enough. Since white dwarfs are compact objects, the gravitational redshift can be quite large (40-80 km/s), and is the predominant source of any shift in wavelength. The mismatch of the true radial velocity with the spectroscopic shift thus leads to a direct measure of the Mass--Radius relation for such objects. Using available catalog information about the known nearby white dwarfs, we estimate how many masses/gravitational redshift measurements can be obtained with an accuracy better than 2%. Nearby white dwarfs are relatively faint objects (10 < V < 15), which can be easily observed by both missions. We also briefly discuss how the presence of a long period planet can mask the astrometric signal of perspective acceleration.
Influencia de los tratamientos térmicos en la deformación en frío de los aceros inoxidables dúplex
Fargas, G.,Manero, J. M.,Anglada, M.,Mateo, A.
Revista de Metalurgia , 2004,
Abstract: The purpose of this paper is to study the compression behavior of a duplex stainless steel after several annealing conditions, in order to simulate the response during cold rolling in the industrial process. For each studied condition, stress-strain curves present serrations in the flow zone due to austenite and ferrite twinning and the austenite phase transformation to martensite. At the same time, it is shown that sigma phase increases the strength and diminish the cold deformation capacity of the steel. Se realizó un estudio del comportamiento a compresión de un acero inoxidable dúplex sometido a distintos tratamientos térmicos de recocido, con el fin de simular su respuesta durante la laminación en frío que tiene lugar en el proceso industrial. Para todas las condiciones estudiadas, las curvas esfuerzo-deformación presentan inestabilidades en la zona plástica, provocadas por el maclado de ambas fases y la transformación de la austenita a martensita. Al mismo tiempo, puede observarse cómo la presencia de fase sigma endurece el acero y limita su capacidad de deformación.
VLA Detection of the Exciting Sources of the Molecular Outflows Associated with L1448 IRS2, IRAS 05327+3404, L43, IRAS 22142+5206, L1211, and IRAS 23545+6508
G. Anglada,Luis F. Rodru00EDguez
Revista mexicana de astronomía y astrofísica , 2002,
Abstract: Presentamos observaciones sensitivas hechas con el Very Large Array" a 3.6 cm hacia nueve campos conteniendo flujos moleculares. Detectamos candidatos para las fuentes excitadoras de flujos moleculares en seis de los campos: L1448 IRS2, IRAS 05327+3404, L43, IRAS 22142+5206, L1211, e IRAS 23545+6508. Discutimos los parámetros de estas fuentes, así como su relación con fuentes detectadas a otras longitudes de onda.
Modeling the Dust and Ammonia Emission in the G 31.41 + 0.31 Hot Molecular Core
M. Osorio,G. Anglada,S. Lizano,P. D`Alessio
Revista mexicana de astronomía y astrofísica , 2003,
Abstract:
Flat-relative optimal extraction. A quick and efficient algorithm for stabilised spectrographs
M. Zechmeister,G. Anglada-Escudé,A. Reiners
Physics , 2013, DOI: 10.1051/0004-6361/201322746
Abstract: Optimal extraction is a key step in processing the raw images of spectra as registered by two-dimensional detector arrays to a one-dimensional format. Previously reported algorithms reconstruct models for a mean one-dimensional spatial profile to assist a properly weighted extraction. We outline a simple optimal extraction algorithm including error propagation, which is very suitable for stabilised, fibre-fed spectrographs and does not model the spatial profile shape. A high signal-to-noise, master-flat image serves as reference image and is directly used as an extraction profile mask. Each extracted spectral value is the scaling factor relative to the cross-section of the unnormalised master-flat which contains all information about the spatial profile as well as pixel-to-pixel variations, fringing, and blaze. The extracted spectrum is measured relative to the flat spectrum. Using echelle spectra of the HARPS spectrograph we demonstrate a competitive extraction performance in terms of signal-to-noise and show that extracted spectra can be used for high precision radial velocity measurement. Pre- or post-flat-fielding of the data is not necessary, since all spectrograph inefficiencies inherent to the extraction mask are automatically accounted for. Also the reconstruction of the mean spatial profile by models is not needed, thereby reducing the number of operations to extract spectra. Flat-relative optimal extraction is a simple, efficient, and robust method that can be applied easily to stabilised, fibre-fed spectrographs.
Low-mass protostars and dense cores in different evolutionary stages in IRAS 00213+6530
G. Busquet,Aina Palau,R. Estalella,J. M. Girart,G. Anglada,I. Sepúlveda
Physics , 2009, DOI: 10.1051/0004-6361/200911845
Abstract: We aim at studying with high angular resolution a dense core associated with a low-luminosity IRAS source, IRAS 00213+6530, in order to investigate whether low mass star formation is really taking place in isolation. We performed observations at 1.2mm with the IRAM 30m telescope, VLA observations at 6cm, 3.6cm, 1.3cm, 7mm, and H2O maser and NH3 lines, and observations with the NASA 70m antenna in CCS and H2O maser. The cm and mm continuum emission, together with the near infrared data from the 2MASS allowed us to identify 3 YSOs, IRS1, VLA8A, and VLA8B, with different radio and infrared properties, and which seem to be in different evolutionary stages. The NH3 emission consists of three clouds. Two of these, MM1 and MM2, are associated with dust emission, while the southern cloud is only detected in NH3. The YSOs are embedded in MM1, where we found evidence of line broadening and temperature enhancements. On the other hand, the southern cloud and MM2 appear to be quiescent and starless. We modeled the radial intensity profile at 1.2mm of MM1. The model fits reasonably well the data, but it underestimates the intensity at small projected distances from the 1.2mm peak, probably due to the presence of multiple YSOs embedded in the envelope. There is a differentiation in the relative NH3 abundance with low values, ~2x10^-8, toward MM1, and high values, up to 10^-6, toward the southern cloud and MM2, suggesting that these clouds could be in a young evolutionary stage. IRAS 00213+6530 is harboring a multiple system of low-mass protostars, indicating that star formation in this cloud is taking place in groups, rather than in isolation. The low-mass YSOs found in IRAS 00213+6530 are in different evolutionary stages suggesting that star formation is taking place in different episodes.
Water maser kinematics in massive star-forming regions: Cepheus A and W75N
J. M. Torrelles,N. A. Patel,S. Curiel,J. F. Gómez,G. Anglada,R. Estalella
Physics , 2012,
Abstract: VLBI multi-epoch water maser observations are a powerful tool to study the dense, warm shocked gas very close to massive protostars. The very high-angular resolution of these observations allow us to measure the proper motions of the masers in a few weeks, and together with the radial velocity, to determine their full kinematics. In this paper we present a summary of the main observational results obtained toward the massive star-forming regions of Cepheus A and W75N, among them: (i) the identification of different centers of high-mass star formation activity at scales of 100 AU; (ii) the discovery of new phenomena associated with the early stages of high-mass protostellar evolution (e.g., isotropic gas ejections); and (iii) the identification of the simultaneous presence of a wide-angle outflow and a highly collimated jet in the massive object Cep A HW2, similar to what is observed in some low-mass protostars. Some of the implications of these results in the study of high-mass star formation are discussed.
Radio Observations of Disks and Jets in Young, Close Binary Systems
G. Anglada,L. F. Rodru00EDguez,J. M. Torrelles,R. Estalella
Revista mexicana de astronomía y astrofísica , 2003,
Abstract:
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