1,728 research outputs found
Sand Transport Studies in Monterey Bay, California: Annual Report, Part 5, 1973
(PDF contains 71 pages
NANTEN 12CO (J=1-0) observations around the star WR 55
Context: A complete study of the molecular and ionized gas in the environs of
the nebula RCW 78 around WR 55 is presented. Aims: The aim of this work is to
investigate the spatial distribution, physical characteristics, and kinematical
properties of the molecular gas linked to the galactic nebula RCW 78 to achieve
a better understanding of its interaction with the star and with the ionized
gas. Methods: This study was based on 12CO(1-0) fully sampled observations of a
region of ~0.45{\deg} in size around the star WR 55 and the nebula RCW 78
obtained with the 4-m NANTEN telescope, radio continuum archival data at 1.4
and 4.85 GHz, obtained from SGPS and PMNRAO Southern Radio Survey,
respectively, and available infrared MIPSGAL images at 24 microns. Results: A
molecular gas component in the velocity range from ~ -58 to -45 km s-1,
compatible with the velocity of the ionized gas, was found to be associated
with the optical nebula. Adopting a distance of ~ 5 kpc, the mass of this
molecular component is about 3.4 x 10^4 Msun. The analysis of the molecular
data revealed the presence of a velocity gradient, in agreement with the Halpha
line. New radiocontinuum flux density determinations confirm the thermal nature
of RCW 78. This indicates that the ionized gas in RCW 78 arises from
photoionization of the molecular gas component in the velocity range from -58
km s-1 to -45 km s-1. A molecular concentration at a velocity of -56.1 km s-1
(identified as C1) is very likely associated with the star HD 117797 and with a
collection of candidate YSOs, lying at a distance of 3.9 kpc, while the rest of
the molecular gas at velocities between -56 and -46 km s-1 constitute an
incomplete ring-like structure which expands around WR 55 at a velocity of
about ~ 5 km s-1. Mechanical energy and time requirements indicate that WR 55
is very capable of sustaining the expansion of the nebula.Comment: 14 pages, 10 figures.Accepted for publication in A&
Environmental Studies of Monterey Bay and the Central California Coastal Zone : Progress Report: First Half of 2nd Year of Operation--July 1971-February 1972
PDF contains 94 pages
Triggered star formation in a molecular shell created by a SNR?
We present a study of a new molecular shell, G126.1-0.8-14, using available
multiwavelegth Galactic plane surveys and optical Gemini observations. A well
defined shell-like structure is observed in the CO(1--0) line emission at (l,b)
= (126.1, -0.8), in the velocity range --10.5 to --15.5 km/s. The HI, emission
shows a region of low emissivity inside G126.1-0.8-14, while radio continuum
observations reveal faint non-thermal emission possibly related to this shell.
Optical spectra obtained with Gemini South show the existence of B-type stars
likely to be associated with G126.1-0.8-14. An estimate of the stellar wind
energy injected by these stars show that they alone can not be able to create
such a structure. On the other hand, one supernova explosion would provide
enough energy to generate the shell. Using the MSX, IRAS, and WISE Point Source
Catalogues we have found about 30 young stellar objects candidates, whose birth
could have been triggered by the expansion of G126.1-0.8-14. In this context,
Sh2-187 could be a consequence of the action on its surroundings of the most
massive (and thus most evolve) of the stars formed by the expanding molecular
shell.Comment: 13 pages, 10 figures, accepted in MNRA
The infrared and molecular environment surrounding the Wolf-Rayet star WR130
We present a study of the molecular CO gas and mid/far infrared radiation
arising from the environment surrounding the Wolf-Rayet (W-R) star 130. We use
the multi-wavelength data to analyze the properties of the dense gas and dust,
and its possible spatial correlation with that of Young Stellar Objects (YSOs).
We use CO J=1-0 data from the FCRAO survey as tracer of the molecular gas, and
mid/far infrared data from the recent WISE and Herschel space surveys to study
the dust continuum radiation and to identify a population of associated
candidate YSOs. The spatial distribution of the molecular gas shows a ring-like
structure very similar to that observed in the HI gas, and over the same
velocity interval. The relative spatial distribution of the HI and CO
components is consistent with a photo-dissociation region. We have identified
and characterized four main and distinct molecular clouds that create this
structure. Cold dust is coincident with the dense gas shown in the CO
measurements. We have found several cYSOs that lie along the regions with the
highest gas column density, and suggest that they are spatially correlated with
the shell. These are indicative of regions of star formation induced by the
strong wind and ionization of the WR star.Comment: 15 pages, 12 figures, 6 Tables. Accepted for publication in MNRA
The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
We present the final data release of observations of lambda 21-cm emission
from Galactic neutral hydrogen over the entire sky, merging the
Leiden/Dwingeloo Survey (LDS: Hartmann & Burton, 1997) of the sky north of
delta = -30 deg with the Instituto Argentino de Radioastronomia Survey (IAR:
Arnal et al., 2000, and Bajaja et al., 2005) of the sky south of delta = -25
deg. The angular resolution of the combined material is HPBW ~ 0.6 deg. The LSR
velocity coverage spans the interval -450 km/s to +400 km/s, at a resolution of
1.3 km/s. The data were corrected for stray radiation at the Institute for
Radioastronomy of the University of Bonn, refining the original correction
applied to the LDS. The rms brightness-temperature noise of the merged database
is 0.07 - 0.09 K. Residual errors in the profile wings due to defects in the
correction for stray radiation are for most of the data below a level of 20 -
40 mK. It would be necessary to construct a telescope with a main beam
efficiency of eta_{MB} > 99% to achieve the same accuracy. The merged and
refined material entering the LAB Survey of Galactic HI is intended to be a
general resource useful to a wide range of studies of the physical and
structural characteristices of the Galactic interstellar environment. The LAB
Survey is the most sensitive Milky Way HI survey to date, with the most
extensive coverage both spatially and kinematically.Comment: 9 pages, 5 figures, accepted for publication by Astronomy &
Astrophysic
Analysis of the application of Socrative as a tool for the learning improvement in a subject of Experimentation in Chemical Engineering
[EN] Experimentation in Chemical Engineering III is a compulsory subject of the third course, semester B of the Chemical Engineering Degree at the Universitat Politècnica de València. It is the last experimental subject of the degree, and the methodology applied is "Project Oriented Learning" (POL). Students carry out experimental sessions, obtaining data that they later use to design an industrial installation based on the laboratory equipment but at a large scale. The course is assesed through the design project and a laboratory report of each experimental session, which is corrected by the teacher and then used as study material for the exam.
Although the development of the subject is satisfactory, the teachers do not know the level that the students have about the experiment to be developed at the beginning of the experimental session and, in most of the cases, mistakes or errors of interpretation that they have had during the practice are detected during correction of the report. Therefore, last year teachers decided to introduce the use of the Socrative tool to conduct surveys to students at the beginning and the end of each session, in order to have real-time feedback on the points that should be most emphasized during the practice, as well as the degree of improvement achieved after the session. Socrative allows to carry out surveys in a simple way through the mobile phone, and to know at the same time the results of the assessment. Thus, students know their mistakes in the test before starting the experimental session, which also is useful to them to assess their level about the topic to develop and pay attention to find out those questions asked in the test in which they have obtained worse results.
This work describes the implementation of this teaching innovation in the laboratory, as well as the results obtained and the degree of improvement achieved by comparing the results at the beginning and end of each experimental session. Finally, it is analysed the usefulness of the innovation, as well as the necessary improvements to continue its application in the future academic courses.GarcĂa-Fayos, B.; Sancho, M.; Arnal Arnal, JM.; Zuriaga Agusti, E.; LĂłpez-Hernández, I. (2021). Analysis of the application of Socrative as a tool for the learning improvement in a subject of Experimentation in Chemical Engineering. IATED. 3727-3733. https://doi.org/10.21125/inted.2021.0773S3727373
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