251 research outputs found
Fatty Acid Methyl Esters as Biosolvents of Epoxy Resins: A Physicochemical Study
The C8 to C18 fatty acid methyl esters (FAME) have been compared as solvents for two epoxy resin pre-polymers, bisphenol A diglycidyl ether (DGEBA) and triglycidyl paminophenol ether (TGPA). It was found that the solubilization limits vary according to the ester and that methyl caprylate is the best solvent of both resins. To explain these solubility performances, physical and chemical properties of FAME were studied, such as the Hansen parameters, viscosity, binary diffusion coefficient and vaporization enthalpy. Determination of the physicochemical parameters of FAME was carried out by laboratory experimentations and by calculation from bibliographic data. The Hansen parameters of FAME and epoxy resins pre-polymers were theoretically and experimentally determined. The FAME chain length showed a long dependence on the binary diffusion parameters and kinematic viscosity, which are mass and momentum transport properties. Moreover, the vaporization enthalpy of these compounds was directly correlated with the solubilization limits
Search for an annual modulation of dark-matter signals with a germanium spectrometer at the Sierra Grande Laboratory
Data collected during three years with a germanium spectrometer at the Sierra
Grande underground laboratory have been analyzed for distinctive features of
annual modulation of the signal induced by WIMP dark matter candidates. The
main motivation for this analysis was the recent suggestion by the DAMA/NaI
Collaboration that a yearly modulation signal could not be rejected at the 90%
confidence level when analyzing data obtained with a high-mass low-background
scintillator detector. We performed two different analyses of the data: First,
the statistical distribution of modulation-significance variables (expected
from an experiment running under the conditions of Sierra Grande) was compared
with the same variables obtained from the data. Second, the data were analyzed
in energy bins as an independent check of the first result and to allow for the
possibility of a crossover in the expected signal. In both cases no
statistically significant deviation from the null result was found, which could
support the hypothesis that the data contain a modulated component. A plot is
also presented to enable the comparison of these results to those of the DAMA
collaboration.Comment: New version accepted by Astroparticle Physics. Changes suggested by
the referee about the theoretical prediction of rates are included.
Conclusions remain unaffected. 14 pages, LaTeX, 7 figures. Uses epsfig macr
'I didn't want to pass that onto my child, being afraid to go to the dentist': Making sense of oral health through narratives of connectedness over the life course
While previous sociological research on oral health has identified the relevance of personal relationships, there is more scope to analyse the mouth through a lens of connectedness. Recent qualitative interviews with 43 older people (65+) in England and Scotland found that participants constructed relational narratives to make sense of their oral health practices. By drawing on ideas of family practices, family display and personal life, we illustrate how the mouth can be understood relationally. Participants presented their own embodied experiences as connected to the actions of their parents. Narratives also reflected how, as parents and grandparents themselves, participants tried to shape the experiences of others. In this way, oral health practices were conceptualised as being about family. This can be seen in self‐narratives that demonstrated how participants located themselves as embedded in webs of ongoing relationships. We highlight the importance of narrated practices of thinking and feeling, whereby participants imagined doing oral health, and indeed family, in different ways. We thereby demonstrate how oral health practices are constituted through family connectedness and at the same time how these practices contribute to the constitution of family. Policy should therefore pay attention to family relations when promoting improvements in oral health practices
Fusion and Binary-Decay Mechanisms in the Cl+Mg System at E/A 8 MeV/Nucleon
Compound-nucleus fusion and binary-reaction mechanisms have been investigated
for the Cl+Mg system at an incident beam energy of E= 282
MeV. Charge distributions, inclusive energy spectra, and angular distributions
have been obtained for the evaporation residues and the binary fragments.
Angle-integrated cross sections have been determined for evaporation residues
from both the complete and incomplete fusion mechanisms. Energy spectra for
binary fragment channels near to the entrance-channel mass partition are
characterized by an inelastic contribution that is in addition to a fully
energy damped component. The fully damped component which is observed in all
the binary mass channels can be associated with decay times that are comparable
to, or longer than the rotation period. The observed mass-dependent cross
sections for the fully damped component are well reproduced by the fission
transition-state model, suggesting a fusion followed by fission origin. The
present data cannot, however, rule out the possibility that a long-lived
orbiting mechanism accounts for part or all of this yield.Comment: 41 pages standard REVTeX file, 14 Figures available upon request -
How important is the context of an adolescent's first alcoholic drink? Evidence that parental provision may reduce later heavy episodic drinking
Objective: This study examined the extent to which a retrospective measure of parental provision of the first alcoholic beverage was related to current heavy episodic drinking and current responsible drinking practices. Sample: 608 14- to 17-year-olds from the 2007 Australian National Drug Strategy Household Survey. Measures: Source of first alcoholic beverage (friends/parents/others), source of current alcohol, age of onset of alcohol use, current responsible drinking practices, and proportion of current friends who drink. Results: Binary logistic and multiple regression procedures revealed that parental provision of an adolescent's first alcoholic beverage predicted lower current heavy episodic drinking, and responsible drinking mediated this association. Discussion: The results suggested that for adolescents who become alcohol users, parental provision of the first drink may reduce subsequent alcohol-related risks compared to introduction to alcohol by friends and other sources. Alcohol-related risks remain significant for adolescents who consume alcohol, independent of who is the provider. Copyright (C) 2012 S. Karger AG, Base
Wave-Particle Studies in the Ion Cyclotron and Lower Hybrid Range of Frequencies in Alcator C-Mod
Setting a baseline for global urban virome surveillance in sewage
The rapid development of megacities, and their growing connectedness across the world is becoming a distinct driver for emerging disease outbreaks. Early detection of unusual disease emergence and spread should therefore include such cities as part of risk-based surveillance. A catch-all metagenomic sequencing approach of urban sewage could potentially provide an unbiased insight into the dynamics of viral pathogens circulating in a community irrespective of access to care, a potential which already has been proven for the surveillance of poliovirus. Here, we present a detailed characterization of sewage viromes from a snapshot of 81 high density urban areas across the globe, including in-depth assessment of potential biases, as a proof of concept for catch-all viral pathogen surveillance. We show the ability to detect a wide range of viruses and geographical and seasonal differences for specific viral groups. Our findings offer a cross-sectional baseline for further research in viral surveillance from urban sewage samples and place previous studies in a global perspective
The Sudbury Neutrino Observatory
The Sudbury Neutrino Observatory is a second generation water Cherenkov
detector designed to determine whether the currently observed solar neutrino
deficit is a result of neutrino oscillations. The detector is unique in its use
of D2O as a detection medium, permitting it to make a solar model-independent
test of the neutrino oscillation hypothesis by comparison of the charged- and
neutral-current interaction rates. In this paper the physical properties,
construction, and preliminary operation of the Sudbury Neutrino Observatory are
described. Data and predicted operating parameters are provided whenever
possible.Comment: 58 pages, 12 figures, submitted to Nucl. Inst. Meth. Uses elsart and
epsf style files. For additional information about SNO see
http://www.sno.phy.queensu.ca . This version has some new reference
A search for the decay
We search for the rare flavor-changing neutral-current decay in a data sample of 82 fb collected with the {\sl BABAR}
detector at the PEP-II B-factory. Signal events are selected by examining the
properties of the system recoiling against either a reconstructed hadronic or
semileptonic charged-B decay. Using these two independent samples we obtain a
combined limit of
at the 90% confidence level. In addition, by selecting for pions rather than
kaons, we obtain a limit of using only the hadronic B reconstruction method.Comment: 7 pages, 8 postscript figures, submitted to Phys. Rev. Let
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