2,660 research outputs found
Investigating Social Perceptions Associated with Water Quality in Morgantown, West Virginia
This dissertation investigates public perceptions of water quality in Morgantown, West Virginia. In recent years, water has become an increasingly critical issue in terms of quantity worldwide, and also in terms of quality. In developed countries such as the United States, water quality is often taken for granted by the general public. Nonetheless, recent water crises in Flint, Michigan and Charleston, West Virginia, are examples showing there are environmental risks associated with human activities. This dissertation explores the context of West Virginia, with coal mining that is decreasing and non-conventional oil and gas drilling that is increasing in the Appalachia region. The main focus of this dissertation is the understanding of tap water quality perceptions and drinking behaviors. The dissertation is divided in five chapters: introduction of the dissertation, context of West Virginia and risk perceptions, modeling drinking behaviors, model building with Structural Equation Modeling (SEM), and proximity analysis. Utilizing an online survey and a mailing survey, we contacted 5492 residents in Morgantown and surrounding areas in Monongalia County to ask them to take part in a research survey about water quality. With a total effective response rate of 11.3%, 603 persons completed the survey (88% residing within Morgantown). The main results of the dissertation are: (1) there exist potential risks of chemical spills in West Virginia, due to the impacts of human activities; (2) most residents are not aware of the quality of their water and do not have strong feelings about their water; (3) bottled water consumption is linked to lower education, lower environmental concern but to higher risks perceptions from drinking from the tap, as well as lower perceptions of organoleptic perceptions from the water (taste, odor, color); (4) using a water filter is mainly linked to higher incomes, low organoleptic perceptions and younger populations; (5) SEM was a useful technique to depict relationships between the different water quality perceptions; (6) SEM found evidence that the construct Perceived Water Quality has multicollinearity issues; (7) Proximity to horizontal wells affect water quality perceptions, but the effect size is rather small. The main implications of these results and this dissertation are the lack of communications from industries and governments to the public. There is a gap between what consumers should know and understand about their water quality. Better information from scientists and local decision-makers should be available to the general public in order to make the right choices for water management and environmental protection. Last but not least, this dissertation argues that education is an important issue for West Virginia water quality and the Appalachia Region in general
A boundary integral formalism for stochastic ray tracing in billiards
Determining the flow of rays or non-interacting particles driven by a force or velocity field is fundamental to modelling many physical processes. These include particle flows arising in fluid mechanics and ray flows arising in the geometrical optics limit of linear wave equations. In many practical applications, the driving field is not known exactly and the dynamics are determined only up to a degree of uncertainty. This paper presents a boundary integral framework for propagating flows including uncertainties, which is shown to systematically interpolate between a deterministic and a completely random description of the trajectory propagation. A simple but efficient discretisation approach is applied to model uncertain billiard dynamics in an integrable rectangular domain
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Mount Baker-Snoqualmie National Forest Winter Aalternative Transportation Study
Reflectance spectra and dielectric functions for Ag in the region of interband transitions
New measurements have been made of the reflectances of single crystals of Ag and of Ag films in the (3.5-30)-eV range. The data were analyzed with the Kramers-Kronig method and the resultant dielectric functions were compared with those in the literature and with recent calculations. We find all structures previously seen, and a new weak peak at 11.5 eV. Our magnitudes for ε2 are in considerably better agreement with those of the calculated spectra than are those in the literature. Second-derivative spectra of the absorption coefficient have been calculated and compared with previously measured thermotransmission spectra, showing the latter to arise primarily by temperature-dependent broadening
Finite difference lattice Boltzmann model with flux limiters for liquid-vapor systems
In this paper we apply a finite difference lattice Boltzmann model to study
the phase separation in a two-dimensional liquid-vapor system. Spurious
numerical effects in macroscopic equations are discussed and an appropriate
numerical scheme involving flux limiter techniques is proposed to minimize them
and guarantee a better numerical stability at very low viscosity. The phase
separation kinetics is investigated and we find evidence of two different
growth regimes depending on the value of the fluid viscosity as well as on the
liquid-vapor ratio.Comment: 10 pages, 10 figures, to be published in Phys. Rev.
Consistent thermodynamic derivative estimates for tabular equations of state
Numerical simulations of compressible fluid flows require an equation of
state (EOS) to relate the thermodynamic variables of density, internal energy,
temperature, and pressure. A valid EOS must satisfy the thermodynamic
conditions of consistency (derivation from a free energy) and stability
(positive sound speed squared). When phase transitions are significant, the EOS
is complicated and can only be specified in a table. For tabular EOS's such as
SESAME from Los Alamos National Laboratory, the consistency and stability
conditions take the form of a differential equation relating the derivatives of
pressure and energy as functions of temperature and density, along with
positivity constraints. Typical software interfaces to such tables based on
polynomial or rational interpolants compute derivatives of pressure and energy
and may enforce the stability conditions, but do not enforce the consistency
condition and its derivatives. We describe a new type of table interface based
on a constrained local least squares regression technique. It is applied to
several SESAME EOS's showing how the consistency condition can be satisfied to
round-off while computing first and second derivatives with demonstrated
second-order convergence. An improvement of 14 orders of magnitude over
conventional derivatives is demonstrated, although the new method is apparently
two orders of magnitude slower, due to the fact that every evaluation requires
solving an 11-dimensional nonlinear system.Comment: 29 pages, 9 figures, 16 references, submitted to Phys Rev
An objective rationale for the choice of regularisation parameter with application to global multiple-frequency S -wave tomography
In a linear ill-posed inverse problem, the regularisation parameter (damping) controls the balance between minimising both the residual data misfit and the model norm. Poor knowledge of data uncertainties often makes the selection of damping rather arbit
Evolution of clouds in radio galaxy cocoons
This letter presents a numerical study of the evolution of an emission line
cloud of initial density 10 cm, temperature K, and size 200 pc,
being overtaken by a strong shock wave. Whereas previous simple models proposed
that such a cloud would either be completely destroyed, or simply shrink in
size, our results show a different and more complex behaviour: due to rapid
cooling, the cloud breaks up into many small and dense fragments, which can
survive for a long time. We show that such rapid cooling behaviour is in fact
expected for a wide range of cloud and shock properties. This process applies
to the evolution of emission line clouds being overtaken by the cocoon of a
radio jet. The resulting small clouds would be Jeans unstable, and form stars.
Our results thus give theoretical credibility to the process of jet induced
star formation, one of the explanations for the alignment of the optical/UV and
radio axis observed in high redshift radio galaxies.Comment: 4 pages, 2 figures, movies available at
http://www.strw.leidenuniv.nl/TheoryGroup/IG-Cloud.htm
A model for shock wave chaos
We propose the following model equation:
that predicts chaotic shock waves.
It is given on the half-line and the shock is located at for any
. Here is the shock state and the source term is assumed
to satisfy certain integrability constraints as explained in the main text. We
demonstrate that this simple equation reproduces many of the properties of
detonations in gaseous mixtures, which one finds by solving the reactive Euler
equations: existence of steady traveling-wave solutions and their instability,
a cascade of period-doubling bifurcations, onset of chaos, and shock formation
in the reaction zone.Comment: 4 pages, 4 figure
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