281 research outputs found
Green River Adjudication v. United States, 404 P.2d 251 (Utah 1965)
Green River Adjudication v. United State
Hardware, Software, and Low-Level Control Scheme Development for a Real-Time Autonomous Rover
The objective of this research is to develop a low-cost autonomous rover platform for experiments in autonomous navigation. This thesis describes the design, development, and testing of an autonomous rover platform, based on the commercial, off-the-shelf Tamiya TXT-1 radio controlled vehicle. This vehicle is outfitted with an onboard computer based on the Mini-ITX architecture and an array of sensors for localization and obstacle avoidance, and programmed with Matlab/SimulinkRTM Real-Time Workshop (RTW) utilizing the Linux Real-Time Application Interface (RTAI) operating system.;First, a kinematic model is developed and verified for the rover. Then a proportional-integral-derivative (PID) feedback controller is developed for translational and rotational velocity regulation. Finally, a hybrid navigation controller is developed combining a potential field controller and an obstacle avoidance controller for waypoint tracking.;Experiments are performed to verify the functionality of the kinematic model and the PID velocity controller, and to demonstrate the capabilities of the hybrid navigation controller. These experiments prove that the rover is capable of successfully navigating in an unknown indoor environment. Suggestions for future research include the integration of additional sensors for localization and creation of multiple platforms for autonomous coordination experiments
State-of-the-Art Review of Bibliographic Control of Higher Education in Canada
During the last two decades the quantity and variety of materials providing information on higher education in Canada have increased greatly. Nevertheless, researchers, administrators, instructors and students find it difficult to identify and locate relevant items. The following article reports on a survey of Canadian agencies and institutions collecting higher education materials; identifies four problem areas - definitions, collection policies, accessibility, and collection co- ordination; and recommends further information exchange and the compilation of a more complete directory of collections in higher education.Au cours des deux derniĂšres dĂ©cennies on a assistĂ© Ă une augmentation consi-dĂ©rable de la quantitĂ© et de la variĂ©tĂ© de l'information ayant trait Ă l'enseigne-ment supĂ©rieur au Canada. Cependant, l'identification et la localisation de ces documents ne sont pas pour autant sans poser des problĂšmes aux chercheurs, administrateurs, enseignants, et Ă©tudiants. L'article suivant signale les rĂ©sultats d'une enquĂȘte portant sur les organismes et Ă©tablissements canadiens qui recueil-lent des documents relatifs Ă l'enseignement supĂ©rieur. Il identifie quatre catĂ©-gories de problĂšmes - dĂ©finitions, politiques de dĂ©veloppement des fonds, acces-sibilitĂ© des documents, et coordination des collections â et recommande l'inten-sification des Ă©changes d'information ainsi que la compilation d'un rĂ©pertoire plus complet pour donner accĂšs Ă ces collections
Capacitance mass sensing of boiling propellants
Capacitance mass sensing of boiling propellant
Neutron Beam Effects on Spin Exchange Polarized He-3
We have observed depolarization effects when high intensity cold neutron
beams are incident on alkali-metal-spin-exchange polarized He-3 cells used as
neutron spin filters. This was first observed as a reduction of the maximum
attainable He-3 polarization and was attributed to a decrease of alkali-metal
polarization, which led us to directly measure alkali-metal polarization and
spin relaxation over a range of neutron fluxes at LANSCE and ILL. The data
reveal a new alkali-metal spin-relaxation mechanism that approximately scales
as the square root of the neutron capture-flux density incident on the cell.
This is consistent with an effect proportional to the recombination-limited ion
concentration, but is much larger than expected from earlier work.Comment: submitted to Physical Review Letter
New measurement of the scattering cross section of slow neutrons on liquid parahydrogen from neutron transmission
Liquid hydrogen is a dense Bose fluid whose equilibrium properties are both
calculable from first principles using various theoretical approaches and of
interest for the understanding of a wide range of questions in many body
physics. Unfortunately, the pair correlation function inferred from
neutron scattering measurements of the differential cross section from different measurements reported in the literature are
inconsistent. We have measured the energy dependence of the total cross section
and the scattering cross section for slow neutrons with energies between
0.43~meV and 16.1~meV on liquid hydrogen at 15.6~K (which is dominated by the
parahydrogen component) using neutron transmission measurements on the hydrogen
target of the NPDGamma collaboration at the Spallation Neutron Source at Oak
Ridge National Laboratory. The relationship between the neutron transmission
measurement we perform and the total cross section is unambiguous, and the
energy range accesses length scales where the pair correlation function is
rapidly varying. At 1~meV our measurement is a factor of 3 below the data from
previous work. We present evidence that these previous measurements of the
hydrogen cross section, which assumed that the equilibrium value for the ratio
of orthohydrogen and parahydrogen has been reached in the target liquid, were
in fact contaminated with an extra non-equilibrium component of orthohydrogen.
Liquid parahydrogen is also a widely-used neutron moderator medium, and an
accurate knowledge of its slow neutron cross section is essential for the
design and optimization of intense slow neutron sources. We describe our
measurements and compare them with previous work.Comment: Edited for submission to Physical Review
Adverse Childhood Experiences and Mental Health Conditions Among Multiracial Adolescents
The relationships between adverse childhood experiences (ACEs) and mental health conditions have received much attention in the literature. A particularly well-documented type of ACE is household dysfunction. However, compared to monoracial youth, little is known about the relationship between this type of ACE and mental health outcomes among multiracial adolescents.
Objective
The objective of this study was to verify the factor structure of the household dysfunction type of ACE using data from the National Survey of Childrenâs Health (NSCH), and then examine whether household dysfunction (measured as a latent construct) was associated with mental health conditions among multiracial adolescents.
Design
We used cross-sectional data collected in 2016 from caregivers who completed the NSCH and analyzed data from a subpopulation of adolescents (12â17) who reported more than one race (nâ=â1,231). Mplus 8.4 was used to conduct confirmatory factor analysis and probit models from a structural equation modeling framework.
Results
Results from this study indicated that the household dysfunction type of ACE, as a latent construct, had good model fit and was significantly associated with depression [standardized coefficient [B]â=â.50, 95% confidence interval [CI] .36, .65], anxiety [Bâ=â.61, 95% CI .48, .73], behavior problems [Bâ=â.58, 95% CI .44, .72], and ADHD [Bâ=â.54, 95% CI .38, .69] for multiracial adolescents.
Conclusions
Household dysfunction may result in adolescents being separated (physically or emotionally) from their caregivers, which may hinder adolescentsâ ability to establish or maintain one of the most important relationships needed to promote racial/ethnic identity development and mental health. Implications for advancements in theory and NSCH are presented
Neutron Beta Decay Studies with Nab
Precision measurements in neutron beta decay serve to determine the coupling
constants of beta decay and allow for several stringent tests of the standard
model. This paper discusses the design and the expected performance of the Nab
spectrometer.Comment: Submitted to Proceedings of the Conference CIPANP12, St.Petersburg,
Florida, May 201
Qweak: A Precision Measurement of the Proton's Weak Charge
The Qweak experiment at Jefferson Lab aims to make a 4% measurement of the
parity-violating asymmetry in elastic scattering at very low of a
longitudinally polarized electron beam on a proton target. The experiment will
measure the weak charge of the proton, and thus the weak mixing angle at low
energy scale, providing a precision test of the Standard Model. Since the value
of the weak mixing angle is approximately 1/4, the weak charge of the proton
is suppressed in the Standard Model, making it
especially sensitive to the value of the mixing angle and also to possible new
physics. The experiment is approved to run at JLab, and the construction plan
calls for the hardware to be ready to install in Hall C in 2007. The
theoretical context of the experiment and the status of its design are
discussed.Comment: 5 pages, 2 figures, LaTeX2e, to be published in CIPANP 2003
proceeding
The Nab Experiment: A Precision Measurement of Unpolarized Neutron Beta Decay
Neutron beta decay is one of the most fundamental processes in nuclear
physics and provides sensitive means to uncover the details of the weak
interaction. Neutron beta decay can evaluate the ratio of axial-vector to
vector coupling constants in the standard model, , through
multiple decay correlations. The Nab experiment will carry out measurements of
the electron-neutrino correlation parameter with a precision of and the Fierz interference term to
in unpolarized free neutron beta decay. These results, along with a more
precise measurement of the neutron lifetime, aim to deliver an independent
determination of the ratio with a precision of that will allow an evaluation of and sensitively
test CKM unitarity, independent of nuclear models. Nab utilizes a novel, long
asymmetric spectrometer that guides the decay electron and proton to two large
area silicon detectors in order to precisely determine the electron energy and
an estimation of the proton momentum from the proton time of flight. The Nab
spectrometer is being commissioned at the Fundamental Neutron Physics Beamline
at the Spallation Neutron Source at Oak Ridge National Lab. We present an
overview of the Nab experiment and recent updates on the spectrometer,
analysis, and systematic effects.Comment: Presented at PPNS201
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