208 research outputs found
Ingress observations of the 1980 eclipse of the symbiotic star CI Cyngni
One of the major results from the IUE may prove to be the knowledge gained by studies of the ultraviolet spectra of symbiotic stars. Symbiotics combine spectral features of a cool M giant like photosphere with strong high excitation emission lines of nebular origin, superposed. The UV spectra are dominated by intense permitted and semiforbidden emission lines and weak continua indicative of hot compact objects and accretion disks. Two symbiotics, AR Pav and CI Cyg are thought to be eclipsing binaries and IUE observations during the 1980 eclipse of CI Cygni are discussed
UV chromospheric and circumstellar diagnostic features among F supergiant stars
A survey of F supergiant stars to evaluate the extension of chromospheric and circumstellar characteristics commonly observed in the slightly cooler G, K, and M supergiant is discussed. An ultraviolet survey was elected since UV features of Mg II and Fe II might persist in revealing outer atmosphere phenomena even among F supergiants. The encompassed spectral types F0 to G0, and luminosity classes Ib, Ia, and Ia-0. In addition, the usefulness of the emission line width-to-luminosity correlation for the G-M stars in both the Ca II and Mg II lines is examined
2D Monte-Carlo Radiative transfer modeling of the disk shaped secondary of Epsilon Aurigae
We present two dimensional Monte-Carlo radiative transfer models for the disk
of the eclipsing binary Aur by fitting its spectral energy
distribution from optical to the far-IR wavelengths. We also report new
observations of Aur made by AKARI in its five mid and far-IR
photometric bands and were used to construct our SED. The disk is optically
thick and has flared disk geometry containing gas and dust with a gas to dust
mass ratio of 100. We have taken the primary of the binary to be a F0Iae-type
post-AGB star and the disk is heated by a B5V hot star with a temperature of
15,000 K at the center of the disk. We take the radius of the disk to be 3.8 AU
for our models as constrained from the IR interferometric imaging observations
of the eclipsing disk. Our models imply that the disk contains grains which are
much bigger than the ISM grains (grain sizes 10 to 100). The grain
chemistry of the disk is carbonaceous and our models show that silicate and ISM
dust chemistry do not reproduce the slope of the observed SED in the mid-IR to
far-IR regions. This implies that the formation of the disk shaped secondary in
Aur system could be the result of accretion of matter and or mass
transfer from the primary which is now a F0Iae post-AGB star. It is not a
proto-planetary disk. The disk is seen nearly edge on with an inclination angle
larger than 85. We propose from our radiative transfer modeling that the
disk is not solid and have a void of 2AU radius at the center within which no
grains are present making the region nearly transparent. The disk is not
massive, its mass is derived to be less than 0.005M.Comment: 27 pages, 5 figures, 2 table
Process for Removing Sulfur and Producing Enhanced Quality and Environmentally Acceptable Products for Energy Production from Coal
A process for producing enhanced quality adsorbent carbons and environmentally acceptable materials for energy production from coal includes an initial step of physically cleaning the coal to remove organic sulfur and mineral tailings. Next, a coal slurry of feedstock and water is prepared. Phosphoric acid is then mixed into the water of the coal slurry to provide by volume 15-85% and more preferably 50-85% phosphoric acid. The slurry is then heated and held in a temperature range between 85° and 230° C. for a period of at least five minutes to allow the phosphoric acid to penetrate deeply into the coal. Then the coal slurry is carbonized at a temperature of between 200°-700° C. for at least five to sixty minutes. The processing produces unique products including a low ash content, low sulfur content carbon solid, a tar with a sulfur content of less than 0.05% of the original feedstock and a gas product having a hydrogen to methane ratio of at least 4:1
Particle Separation/Purification System, Diffuser and Related Methods
A separator and related separation methods are for intended use in separating particles having a selected charge from a particle mixture entrained in or carried by a fluid flow. The separator comprises a tubular, elongated body for receiving the fluid flow. At least one and preferably a pair of electrodes may be provided to create an electric field in at least a portion of the body through which the fluid flow passes, and at least one partition defines first and second channels for receiving the flow downstream of the portion of the body including the electric field. In one embodiment, the electrode is oriented such that a direction of gravity acting on particles having a selected charge passing through the electric field directs the selectively charged particles towards the first or second electrode. A system may incorporate the separator, along with a diffuser
Particle Separation/Purification System, Diffuser and Related Methods
A separator for intended use in separating particles having a selected charge from a particle mixture entrained in or carried by a fluid flow is disclosed. The separator comprises a tubular, elongated body for receiving the fluid flow. At least one and preferably a pair of electrodes may be provided to create an electric field in at least a portion of the body through which the fluid flow passes, and at least one partition defines first and second channels for receiving the flow downstream of the portion of the body including the electric field. In one embodiment, the electrode is oriented such that a direction of an electrical field force acting on particles having a selected charge passing through the electric field is not perpendicular to a direction of gravity. A system incorporating the separator is disclosed, along with a diffuser and related methods
Ultraviolet and X-ray detection of the 56 Peg system (KO 2p + WD)
Both IUE short and long wavelength exposures of the 56 Peg system are discussed. This mild barium star has an X-ray luminosity of 3 x 10 to the 31st power ergs/1, comparable to the rapidly rotating RS CVn binary systems, yet lies in a region of the HR diagram where stellar X-rays are generally not observed. This cool, bright giant is not a rapid rotator and the key to understanding its emission lies in the recent discovery of its white dwarf companion. Accretion onto the white dwarf of approximately 0.1% of the stellar wind of the primary is sufficient to power an X-ray source of the observed luminosity. Reprocessing of the X-rays in the cool dense stellar wind explains the origin of the UV emission line spectrum, and may explain the time varying asymmetry of the Mg 2 kappa line profile that is observed. Graphs which show observed fluxes and wavelengths are discussed
Recommended from our members
Pulverization Induced Charge: In-Line Dry Coal Cleaning
The technical feasibility of separating mineral matter and pyrite from coal as it is transported from pulverizers to burners in pulverized coal combustion units will be examined. The charge imparted on coal during pulverization and transport to pulverized coal (PC) burners in a utility boiler will be quantified. In addition to field charge measurements, an existing computational model will be extended to numerically simulate charged particle motion in a turbulent gas through an electric field. Results from the field tests and numerical modeling will be employed in design and construction of a laboratory scale pulverizer/classifier. This laboratory unit will be used to quantify the magnitude and differential charge imparted on bituminous and subbituminous coals during pulverization and classification at temperatures and with gaseous constituents typical to utility PC units. An electrostatic separator, designed for in-line operation between pulverizers and PC boilers, will be used to clean prepulverized coals. Theoretical and experimental data are to be used in preparing a preliminary design for a full-scale, (15 ton/hr) in-line, electrostatic coal cleaning device. Finally, the economic potential for application to PC units will be assessed
Method and Apparatus for Triboelectric-Centrifugal Separation
A method for separating two species of particles present in raw feedstock includes electrically charging at least one of the species of particles being separated. Next is the subjecting of the particles to both centrifugal and electrostatic forces. This is done in a manner so as to provide an additive effect and thereby achieve enhanced separation of the two particle species. An apparatus for processing the raw feedstock in accordance with the method is also disclosed
Multi-wavelength observations of the peculiar red giant HR 3126
Ultraviolet observations of the red giant HR 3126 are combined with multi-wavelength data in order to provide a firmer basis for explaining the arc-minute sized nebula surrounding the object. Possibilities as to the location of HR 3126 on the Hertzsprung-Russel diagram, and to the formation mechanisms of the reflection nebula IC 2220 associated with it, are summarized
- …