12,817 research outputs found
The Inhomogeneous Hall's Ray
We show that the inhomogenous approximation spectrum, associated to an
irrational number \alpha\ always has a Hall's Ray; that is, there is an
\epsilon>0 such that [0,\epsilon) is a subset of the spectrum. In the case when
\alpha\ has unbounded partial quotients we show that the spectrum is just a
ray.Comment: Fixed typos in bibliograph
Spectra of Maser Radiation from a Turbulent, Circumnuclear Accretion Disk. III. Circular polarization
Calculations are performed for the circular polarization of maser radiation
from a turbulent, Keplerian disk that is intended to represent the sub-parsec
disk at the nucleus of the galaxy NGC4258. The polarization in the calculations
is a result of the Zeeman effect in the regime in which the Zeeman splitting is
much less than the spectral linebreadth. Plausible configurations for turbulent
magnetic and velocity fields in the disk are created by statistical methods.
This turbulence, along with the Keplerian velocity gradients and the blending
of the three hyperfine components to form the masing
transition of water, are key ingredients in determining the appearance of the
polarized spectra that are calculated. These spectra are quite different from
the polarized spectra that would be expected for a two-level transition where
there is no hyperfine structure. The effect of the hyperfine structure on the
polarization is most striking in the calculations for the maser emission that
represents the central (or systemic) features of NGC4258. Information about
magnetic fields is inferred from observations for polarized maser radiation and
bears on the structure of accretion disks.Comment: Latex, uses aastex, eucal, to be published in the Astrophysical
Journa
Performance of the Colorado wind-profiling network, part 1.5A
The Wave Propagation Laboratory (WPL) has operated a network of radar wind Profilers in Colorado for about 1 year. The network consists of four VHF (50-MHz) radars and a UHF (915-MHz) radar. The Platteville VHF radar was developed by the Aeronomy Laboratory (AL) and has been operated jointly by WPL and AL for several years. The other radars were installed between February and May 1983. Experiences with these radars and some general aspects of tropospheric wind measurements with Doppler radar are discussed
Detection of solvents using a distributed fibre optic sensor
A fibre optic sensor that is capable of distributed detection of liquid solvents is presented. Sensor interrogation using optical time domain reflectometry (OTDR) provides the capability of locating solvent spills to a precision of ±2 m over a total sensor length that may extend to 20 km
Flow of nitrogen-pressurized Halon 1301 in fire extinguishing systems
Halon 1301 which is a halocarbon fire extinguishing agent (CBrF3) used by the U.S. Army for vehicle fire suppression is discussed. Halon 1301 is discharged under nitrogen pressure, and the Halon-nitrogen mixture is a two phase, two component mixture that obeys compressible fluid laws and exhibits choking effects. A computer model was developed to analyze the discharge of Halon and nitrogen from a storage bottle through pipes and nozzles. The model agrees well with data from Halon 1301 discharge tests. The discharge time depends mainly on nozzle area and pipe volume, for given initial conditions. Graphs were developed for estimating discharge times. A nozzle employing multiple concentric converging/diverging nozzles was developed which gave hemispherical coverage
Comment on “Dosimetric evaluations of the interplay effect in respiratory‐gated intensity‐modulated radiation therapy” [Med. Phys. 36, 893–903 (2009)]
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134968/1/mp2483.pd
Sun-Sized Water Vapor Masers in Cepheus A
We present the first VLBI observations of a Galactic water maser (in Chepeus
A) made with a very long baseline interferometric array involving the
RadioAstron Earth-orbiting satellite station as one of its elements. We
detected two distinct components at -16.9 and 0.6 km/s with a fringe spacing of
66 microarcseconds. In total power, the 0.6 km/s component appears to be a
single Gaussian component of strength 580 Jy and width of 0.7 km/s.
Single-telescope monitoring showed that its lifetime was only 8~months. The
absence of a Zeeman pattern implies the longitudinal magnetic field component
is weaker than 120 mG. The space-Earth cross power spectrum shows two
unresolved components smaller than 15 microarcseconds, corresponding to a
linear scale of 1.6 x 10^11 cm, about the diameter of the Sun, for a distance
of 700 pc, separated by 0.54 km/s in velocity and by 160 +/-35 microarcseconds
in angle. This is the smallest angular structure ever observed in a Galactic
maser. The brightness temperatures are greater than 2 x 10^14K, and the line
widths are 0.5 km/s. Most of the flux (about 87%) is contained in a halo of
angular size of 400 +/- 150 microarcseconds. This structure is associated with
the compact HII region HW3diii. We have probably picked up the most prominent
peaks in the angular size range of our interferometer. We discuss three
dynamical models: (1) Keplerian motion around a central object, (2) two chance
overlapping clouds, and (3) vortices caused by flow around an obstacle (i.e.,
von Karman vortex street) with Strouhal number of about~0.3.Comment: 15 pages, 9 figures. Accepted for publication in ApJ, February 16,
201
The Effect of Fermented Organic Feed Usage On The Health Status of Kampong Chicken
This research aims to determine the effect of the use of fermented organic feed to the health status of Kampong chickens based on the number of bacteria in the intestine and their blood profile. The experiment method with Completely Randomized Design (CRD) was utilized in this study. There were four treatments, T0 = organic feed without fermentation, T1 = organic feed with fermented rice bran, T2 = organic feed with fermented corn and T3
= a combination of fermented rice bran and corn. The fermentation was done using yeast, Saccharomyces
cerevisiae, each of these treatments consisted of ten chickens. The parameters measured were the colony
number of Escherichia coli, Salmonella sp. in the intestine, the number of erythrocytes, leukocyte, level of hemoglobin and hematocrit, atotal of plasma protein and blood glucose. The data were analyzed by quantitative descriptive analysis. The results show that the fermented rice bran provides the best growth inhibitory effect of E. coli, at 232.6 x 10 cfu/ml, towards Salmonella sp. has been reached by the combination of fermented rice
bran and corn, at 794 x 103
cfu/ml. The number of erythrocytes, leukocytes, hematocrit level and a total of plasma protein of blood samples obtained good results by the standard of the literature. The hemoglobin level in
rice bran and corn fermented according to the standard level, although in control and the combination of fermented rice bran and corn were less than standard, 6.82 g/dl and 6.30 g/dl respectively.
- …