1,382 research outputs found
Effects of commercially available colored lenses on color perception in a normal population
Effects upon color perception were studied using the Corning Medical Optics CPF lenses and the Younger Optics PLS lenses. Measurements were obtained using the Farnsworth 15-hue (D-15) color test. Color perception errors associated with the respective lenses were statistically analyzed. Comparisons of these individual lens errors were then made among all the lenses included in the study. All the lenses significantly altered color perception in some or all of the visible spectrum. In all cases, the Corning CPF lenses had either equal or lesser effects upon color perception errors than did the Younger PLS lenses
Ab initio nucleon-nucleus elastic scattering with chiral effective field theory uncertainties
Background: Effective interactions for nucleon-nucleus () elastic
scattering from first principles require the use of the same nucleon-nucleon
() interaction in the structure and reaction calculations, and a consistent
treatment of the relevant operators at each order.
Purpose: Truncation uncertainties of chiral forces have been studied for
scattering observables in few-body systems and for bound state properties of
light nuclei. We extend this to elastic scattering.
Methods: With the spectator expansion of multiple scattering theory and the
no-core shell model, we use a chiral interaction from the LENPIC collaboration
to consistently calculate the leading order effective interaction up to
third chiral order (N2LO) and extract elastic scattering observables. We
quantify the chiral truncation error using pointwise and correlated methods.
Results: We analyze proton-O and neutron-C elastic scattering
observables between 65 and 185 MeV projectile kinetic energy. We find
qualitatively similar results for the chiral truncation uncertainties as in
few-body systems, which we assess using similar diagnostic tools. The
order-by-order convergence of the scattering observables for O and
C is reasonable near 100 MeV, but for higher energies the expansion
parameter becomes too large to converge. We find a near-perfect correlation
between the neutron differential cross section and the Wolfenstein
amplitudes for small momentum transfers.
Conclusions: The tools used to study the convergence of a chiral
interaction in few-body systems can be applied to scattering with minor
changes. The interaction used here gives a good description of O
and C scattering observables as low as 65 MeV. The very forward
direction of the neutron differential cross section mirrors the behavior of the
interaction amazingly well.Comment: 17 pages, 13 figures, 1 tabl
Significant issues in proof testing: A critical appraisal
Issues which impact on the interpretation and quantification of proof test benefits are reviewed. The importance of each issue in contributing to the extra quality assurance conferred by proof testing components is discussed, particularly with respect to the application of advanced fracture mechanics concepts to enhance the flaw screening capability of a proof test analysis. Items covered include the role in proof testing of elastic-plastic fracture mechanics, ductile instability analysis, deterministic versus probabilistic analysis, single versus multiple cycle proof testing, and non-destructive examination (NDE). The effects of proof testing on subsequent service life are reviewed, particularly with regard to stress redistribution and changes in fracture behavior resulting from the overload. The importance of proof test conditions are also addressed, covering aspects related to test temperature, simulation of service environments, test media and the application of real-time NDE. The role of each issue in a proof test methodology is assessed with respect to its ability to: promote proof test practice to a state-of-the-art; aid optimization of proof test design; and increase awareness and understanding of outstanding issues
Strain Rate Dependence and Short-Term Relaxation Behavior of a Thermoset Polymer at Elevated Temperature: Experiment and Modeling,"
The inelastic deformation behavior of polymerization of monomeri
Circulating endothelial cells are elevated in patients with type 2 diabetes mellitus independently of HbA1c
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Guidelines for Proof Test Analysis
These guidelines integrate state-of-the-art elastic-plastic fracture mechanics (EPFM) and proof test implementation issues into a comprehensive proof test analysis procedure in the form of a road map which identifies the types of data, fracture mechanics based parameters, and calculations needed to perform flaw screening and minimum proof load analyses of fracture critical components. Worked examples are presented to illustrate the application of the road map to proof test analysis. The state-of-the art fracture technology employed in these guidelines is based on the EPFM parameter, J, and a pictorial representation of a J fracture analysis, called the failure assessment diagram (FAD) approach. The recommended fracture technology is validated using finite element J results, and laboratory and hardware fracture test results on the nickel-based superalloy Inconel 718, the aluminum alloy 2024-T3511, and ferritic pressure vessel steels. In all cases the laboratory specimens and hardware failed by ductile mechanisms. Advanced proof test analyses involving probability analysis and multiple-cycle proof testing (MCPT) are addressed. Finally, recommendations are provided on how to account for the effects of the proof test overload on subsequent service fatigue and fracture behaviors
NASA Contractor Report: Guidelines for Proof Test Analysis
These Guidelines integrate state-of-the-art Elastic-Plastic Fracture Mechanics (EPFM) and proof test implementation issues into a comprehensive proof test analysis procedure in the form of a Road Map which identifies the types of data, fracture mechanics based parameters, and calculations needed to perform flaw screening and minimum proof load analyses of fracture critical components. Worked examples are presented to illustrate the application of the Road Map to proof test analysis. The state-of-the-art fracture technology employed in these Guidelines is based on the EPFM parameter, J, and a pictorial representation of a J fracture analysis, called the Failure Assessment Diagram (FAD) approach. The recommended fracture technology is validated using finite element J results, and laboratory and hardware fracture test results on the nickel-based superalloy IN-718, the aluminum alloy 2024-T351 1, and ferritic pressure vessel steels. In all cases the laboratory specimens and hardware failed by ductile mechanisms. Advanced proof test analyses involving probability analysis and Multiple Cycle Proof Testing (MCPT) are addressed. Finally, recommendations are provided on to how to account for the effects of the proof test overload on subsequent service fatigue and fracture behaviors
Efficacy and safety of a novel delayed-release risedronate 35Â mg once-a-week tablet
Dosing regimens of oral bisphosphonates are inconvenient and contribute to poor compliance. The bone mineral density response to a once weekly delayed-release formulation of risedronate given before or following breakfast was non-inferior to traditional immediate-release risedronate given daily before breakfast. Delayed-release risedronate is a convenient regimen for oral bisphosphonate therapy
Differential Regulation of the Period Genes in Striatal Regions following Cocaine Exposure
Several studies have suggested that disruptions in circadian rhythms contribute to the pathophysiology of multiple psychiatric diseases, including drug addiction. In fact, a number of the genes involved in the regulation of circadian rhythms are also involved in modulating the reward value for drugs of abuse, like cocaine. Thus, we wanted to determine the effects of chronic cocaine on the expression of several circadian genes in the Nucleus Accumbens (NAc) and Caudate Putamen (CP), regions of the brain known to be involved in the behavioral responses to drugs of abuse. Moreover, we wanted to explore the mechanism by which these genes are regulated following cocaine exposure. Here we find that after repeated cocaine exposure, expression of the Period (Per) genes and Neuronal PAS Domain Protein 2 (Npas2) are elevated, in a somewhat regionally selective fashion. Moreover, NPAS2 (but not CLOCK (Circadian Locomotor Output Cycles Kaput)) protein binding at Per gene promoters was enhanced following cocaine treatment. Mice lacking a functional Npas2 gene failed to exhibit any induction of Per gene expression after cocaine, suggesting that NPAS2 is necessary for this cocaine-induced regulation. Examination of Per gene and Npas2 expression over twenty-four hours identified changes in diurnal rhythmicity of these genes following chronic cocaine, which were regionally specific. Taken together, these studies point to selective disruptions in Per gene rhythmicity in striatial regions following chronic cocaine treatment, which are mediated primarily by NPAS2. © 2013 Falcon et al
Integrated fiber-mirror ion trap for strong ion-cavity coupling
We present and characterize fiber mirrors and a miniaturized ion-trap design developed to integrate a fiber-based Fabry-Perot cavity (FFPC) with a linear Paul trap for use in cavity-QED experiments with trapped ions. Our fiber-mirror fabrication process not only enables the construction of FFPCs with small mode volumes, but also allows us to minimize the influence of the dielectric fiber mirrors on the trapped-ion pseudopotential. We discuss the effect of clipping losses for long FFPCs and the effect of angular and lateral displacements on the coupling efficiencies between cavity and fiber. Optical profilometry allows us to determine the radii of curvature and ellipticities of the fiber mirrors. From finesse measurements, we infer a single-atom cooperativity of up to 12 for FFPCs longer than 200 μm in length; comparison to cavities constructed with reference substrate mirrors produced in the same coating run indicates that our FFPCs have similar scattering losses. We characterize the birefringence of our fiber mirrors, finding that careful fiber-mirror selection enables us to construct FFPCs with degenerate polarization modes. As FFPCs are novel devices, we describe procedures developed for handling, aligning, and cleaning them. We discuss experiments to anneal fiber mirrors and explore the influence of the atmosphere under which annealing occurs on coating losses, finding that annealing under vacuum increases the losses for our reference substrate mirrors. X-ray photoelectron spectroscopy measurements indicate that these losses may be attributable to oxygen depletion in the mirror coating. Special design considerations enable us to introduce a FFPC into a trapped ion setup. Our unique linear Paul trap design provides clearance for such a cavity and is miniaturized to shield trapped ions from the dielectric fiber mirrors. We numerically calculate the trap potential in the absence of fibers. In the experiment additional electrodes can be used to compensate distortions of the potential due to the fibers. Home-built fiber feedthroughs connect the FFPC to external optics, and an integrated nanopositioning system affords the possibility of retracting or realigning the cavity without breaking vacuum
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