25,384 research outputs found
Analysis of non-premixed turbulent reacting flows
Studies of chemical reactions occurring in turbulent flows are important in the understanding of combustion and other applications. Current numerical methods are limited in their applications due to the numerical resolution required to completely capture all length scales, but, despite the fact that realistic combustion cannot be solved completely, numerical simulations can be used to give insight into the interaction between the processes of turbulence and chemical reaction. The objective was to investigate the effects of turbulent motion on the effects of chemical reaction to gain some insight on the interaction of turbulence, molecular diffusion, and chemical reaction to support modeling efforts. A direct turbulence simulation spectral code was modified to include the effects of chemical reaction and applied to an initial value problem of chemical reaction between non-premixed species. The influence of hydrodynamics on the instantaneous structure of the reaction was investigated. The local scalar dissipation rates and the local reaction rates were examined to determine the influence of vorticity or rate of strain on the reaction and the structure of the scalar field
N-body Monte Carlo simulation of specific lunar orbiter missions
N-body Monte Carlo simulation of specific lunar orbiter mission
A slip model for micro/nano gas flows induced by body forces
A slip model for gas flows in micro/nano-channels induced by external body
forces is derived based on Maxwell's collision theory between gas molecules and
the wall. The model modifies the relationship between slip velocity and
velocity gradient at the walls by introducing a new parameter in addition to
the classic Tangential Momentum Accommodation Coefficient. Three-dimensional
Molecular Dynamics simulations of helium gas flows under uniform body force
field between copper flat walls with different channel height are used to
validate the model and to determine this new parameter
Upsilon Production In pp Collisions For Forward Rapidities At LHC
This is a continuation of recent studies of production at the
LHC in pp collisions. Our previous studies were for rapidity y=-1 to 1 for the
CMS detector, while the present study is for y=2.5 to 4.0 at the LHC.Comment: 5 pages, 2 figure
An Introduction to Alcohol Use Disorder and Motivational Interviewing at Henry Abbott Technical High School in Danbury, CT
We presented to high school students interested in careers in health about alcohol use and motivational interviewing. We demonstrated effective motivational interviewing skills including asking open ended questions, using non-judgmental language and eliciting change talk from patients. Finally we facilitated breakout sessions which allowed students to practice identifying at risk behaviors and to practice motivational interviewing.https://scholarworks.uvm.edu/fmclerk/1137/thumbnail.jp
Preliminary Results from the Caltech Core-Collapse Project (CCCP)
We present preliminary results from the Caltech Core-Collapse Project (CCCP),
a large observational program focused on the study of core-collapse SNe.
Uniform, high-quality NIR and optical photometry and multi-epoch optical
spectroscopy have been obtained using the 200'' Hale and robotic 60''
telescopes at Palomar, for a sample of 50 nearby core-collapse SNe. The
combination of both well-sampled optical light curves and multi-epoch
spectroscopy will enable spectroscopically and photometrically based subtype
definitions to be disentangled from each other. Multi-epoch spectroscopy is
crucial to identify transition events that evolve among subtypes with time. The
CCCP SN sample includes every core-collapse SN discovered between July 2004 and
September 2005 that was visible from Palomar, found shortly (< 30 days) after
explosion (based on available pre-explosion photometry), and closer than ~120
Mpc. This complete sample allows, for the first time, a study of core-collapse
SNe as a population, rather than as individual events. Here, we present the
full CCCP SN sample and show exemplary data collected. We analyze available
data for the first ~1/3 of the sample and determine the subtypes of 13 SNe II
based on both light curve shapes and spectroscopy. We discuss the relative SN
II subtype fractions in the context of associating SN subtypes with specific
progenitor stars.Comment: To appear in the proceedings of the meeting "The Multicoloured
Landscape of Compact Objects and their Explosive Origins", Cefalu, Italy,
June 2006, to be published by AIP, Eds. L. Burderi et a
A novel laser ranging system for measurement of ground-to-satellite distances
A technique was developed for improving the precision of laser ranging measurements of ground-to-satellite distances. The method employs a mode-locked laser transmitter and utilizes an image converter tube equipped with deflection plates in measuring the time of flight of the laser pulse to a distant retroreflector and back. Samples of the outgoing and returning light pulses are focussed on the photocathode of the image converter tube, whose deflection plates are driven by a high-voltage 120 MHz sine wave derived from a very stable oscillator. From the relative positions of the images produced at the output phosphor by the two light pulses, it is possible to make a precise determination of the fractional amount by which the time of flight exceeds some large integral multiple of the period of the deflection sinusoid
A Spectropolarimetric Comparison of the Type II-Plateau Supernovae SN 2008bk and SN 2004dj
The Type II-Plateau supernova (SN II-P) SN 2004dj was the first SN II-P for
which spectropolarimetry data were obtained with fine temporal sampling before,
during, and after the fall off of the photometric plateau -- the point that
marks the transition from the photospheric to the nebular phase in SNe II-P.
Unpolarized during the plateau, SN 2004dj showed a dramatic spike in
polarization during the descent off of the plateau, and then exhibited a smooth
polarization decline over the next two hundred days. This behavior was
interpreted by Leonard et al. (2006) as evidence for a strongly non-spherical
explosion mechanism that had imprinted asphericity only in the innermost
ejecta. In this brief report, we compare nine similarly well-sampled epochs of
spectropolarimetry of the Type II-P SN 2008bk to those of SN 2004dj. In
contrast to SN 2004dj, SN 2008bk became polarized well before the end of the
plateau and also retained a nearly constant level of polarization through the
early nebular phase. Curiously, although the onset and persistence of
polarization differ between the two objects, the detailed spectropolarimetric
characteristics at the epochs of recorded maximum polarization for the two
objects are extremely similar, feature by feature. We briefly interpret the
data in light of non-Local-Thermodynamic Equilibrium, time-dependent
radiative-transfer simulations specifically crafted for SN II-P ejecta.Comment: 4 pages, 1 figure, to appear in AIP conference proceedings: Stellar
Polarimetry, From Birth to Death, eds. J. Hoffman, B. Whitney, and J.
Bjorkma
Symbol synchronization in convolutionally coded systems
Alternate symbol inversion is sometimes applied to the output of convolutional encoders to guarantee sufficient richness of symbol transition for the receiver symbol synchronizer. A bound is given for the length of the transition-free symbol stream in such systems, and those convolutional codes are characterized in which arbitrarily long transition free runs occur
- …
