6,636 research outputs found
Precision die-punch for trimming the conductors of flat conductor cable
Operation trims conductor to width of 0.004 in. and consistently leaves 0.035 in. spaces between adjacent conductors, adapting cable for termination with standard plug
Local molecular field theory for effective attractions between like charged objects in systems with strong Coulomb interactions
Strong short ranged positional correlations involving counterions can induce
a net attractive force between negatively charged strands of DNA, and lead to
the formation of ion pairs in dilute ionic solutions. But the long range of the
Coulomb interactions impedes the development of a simple local picture. We
address this general problem by mapping the properties of a nonuniform system
with Coulomb interactions onto those of a simpler system with short ranged
intermolecular interactions in an effective external field that accounts for
the averaged effects of appropriately chosen long ranged and slowly varying
components of the Coulomb interactions. The remaining short ranged components
combine with the other molecular core interactions and strongly affect pair
correlations in dense or strongly coupled systems. We show that pair
correlation functions in the effective short ranged system closely resemble
those in the uniform primitive model of ionic solutions, and illustrate the
formation of ion pairs and clusters at low densities. The theory accurately
describes detailed features of the effective attraction between two equally
charged walls at strong coupling and intermediate separations of the walls. New
analytical results for the minimal coupling strength needed to get any
attraction and for the separation where the attractive force is a maximum are
presented.Comment: 8 pages, 5 figures. To be published in PNA
Implications for welfare, productivity and sustainability of the variation in reported levels of mortality for laying hen flocks kept in different housing systems: A meta-analysis of ten studies
Data from ten sources comprising 3,851 flocks were modelled to identify variation in levels
of mortality in laying hens. The predicted increase with age was curvilinear with significant
variation between the seven breed categories. Mortality was higher in loose housing systems
than in cages and variable within system, confirming previous reports. Cumulative
mortality (CM) was higher in flocks with intact beaks (χ2 = 6.03; df 1; p = 0.014) than in
those with trimmed beaks. Most data were available for free-range systems (2,823 flocks),
where producer recorded CM at 60–80 weeks of age averaged 10% but with a range from
0% to 69.3%. Life cycle assessment showed that the main effect of increased levels of hen
mortality is to increase the relative contribution of breeding overheads, so increasing environmental
burdens per unit of production. Reducing CM to levels currently achieved by the
1st quartile could reduce flock greenhouse gas emissions by as much as 25%. Concurrently
this would enhance hen welfare and better meet the expectation of egg consumers. More
research to understand the genetic x environment interaction and detailed records of the
causes of mortality is required so that improved genotypes can be developed for different
systems and different breeds can be better managed within systems
Density fluctuations and the structure of a nonuniform hard sphere fluid
We derive an exact equation for density changes induced by a general external
field that corrects the hydrostatic approximation where the local value of the
field is adsorbed into a modified chemical potential. Using linear response
theory to relate density changes self-consistently in different regions of
space, we arrive at an integral equation for a hard sphere fluid that is exact
in the limit of a slowly varying field or at low density and reduces to the
accurate Percus-Yevick equation for a hard core field. This and related
equations give accurate results for a wide variety of fields
Molecular oxygen densities from rocket measurements of Lyman-alpha absorption profiles
Molecular oxygen density measurements in upper atmosphere by absorption spectroscopy using solar Lyman alpha radiatio
Multiedge slitter for FCC
Tool cuts multiple slits up to 3 in. long between conductors of flat conductor cables up to 3 in. wide to prepare them for termination on terminal boards or in multipin connectors
Robust Growth Determinants
This paper investigates the robustness of determinants of economic growth in the presence of model uncertainty, parameter heterogeneity and outliers. The robust model averaging approach introduced in the paper uses a flexible and parsimonious mixture modeling that allows for fat-tailed errors compared to the normal benchmark case. Applying robust model averaging to growth determinants, the paper finds that eight of eighteen variables found to be significantly related to economic growth by Sala-i-Martin et al. (2004) are sensitive to deviations from benchmark model averaging. For example, the GDP shares of mining or government consumption, are no longer robust or economically significant once deviations from the normal benchmark assumptions are allowed. The paper identifies outlying observations - most notably Botswana - in explaining economic growth in a cross-section of countries
Investigation of the D and E region during the IQSY Final report, 1964 - 1965
Nike-Apache rocket measurements of lower ionosphere during International Quiet Sun Yea
Local elastic response measured near the colloidal glass transition
We examine the response of a dense colloidal suspension to a local force
applied by a small magnetic bead. For small forces, we find a linear
relationship between the force and the displacement, suggesting the medium is
elastic, even though our colloidal samples macroscopically behave as fluids. We
interpret this as a measure of the strength of colloidal caging, reflecting the
proximity of the samples' volume fractions to the colloidal glass transition.
The strain field of the colloidal particles surrounding the magnetic probe
appears similar to that of an isotropic homogeneous elastic medium. When the
applied force is removed, the strain relaxes as a stretched exponential in
time. We introduce a model that suggests this behavior is due to the diffusive
relaxation of strain in the colloidal sample.Comment: long-delayed followup paper to Habdas et al., EPL 67, 477-483 (2004
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