3,189 research outputs found
Performance of a 1380-foot-per-second-tip-speed axial-flow compressor rotor with a blade tip solidity of 1.3
Aerodynamic design parameters are presented along the overall and blade element performance, of an axial flow compressor rotor designed to study the effects of blade solidity on efficiency and stall margin. At design speed the peak efficiency was 0.844 and occurred at an equivalent weight flow of 63.5 lb/sec with a total pressure ratio of 1.801. Design efficiency, pressure ratio, and weight flow 0.814, 1.65, and 65.3(41.1 lb/sec/sq ft of annulus area), respectively. Stall margin for design speed was 6.4 percent based on the weight flow and pressure ratio values at peak efficiency and just prior to stall
Internal conversion coefficients for superheavy elements
The internal conversion coefficients (ICC) were calculated for all atomic
subshells of the elements with 104<=Z<=126, the E1...E4, M1...M4
multipolarities and the transition energies between 10 and 1000 keV. The atomic
screening was treated in the relativistic Hartree-Fock-Slater model. The Tables
comprising almost 90000 subshell and total ICC were recently deposited at LANL
preprint server.Comment: 6 pages including 3 figures, needs files myown.sty and epsfig.sty
(both included
Examining a Neural Measure of Attentional Bias to Emotional Faces in Social Anxiety and Depression
Cognitive theories suggest that attentional biases may contribute to both social anxiety and depression, such that attention may be biased to focus on or away from certain information (e.g., rejecting or sad images; Clark & McManus, 2002; Lemoult & Gotlib, 2019). Although research is mixed, recent studies using a neural measure called the N2pc (an event-related potential) has indicated attentional biases in social anxiety. However, little N2pc research has examined depression or co-occurring depression and social anxiety.
The current study used electroencephalography to measure the N2pc during a dot-probe task in which images of faces with emotional or neutral expressions competed for attention. Undergraduates (N = 102) completed the task and self-report measures of social anxiety and depression. Hierarchical linear regressions examined the hypotheses that social anxiety would be associated with attentional biases toward both angry and disgust faces and that depression would be associated with biases away from happy faces and toward sad faces.
Social anxiety was associated with a more negative N2pc for (i.e. greater bias toward) happy faces (β = -.32, p \u3c .01) when holding depression constant. Depression was only marginally associated with bias toward sad faces (β = -.20, p = .09), given average social anxiety, and the interaction of depression and social anxiety marginally predicted less bias toward sad faces (β = .21, p = .08).
The social anxiety bias toward happy faces supports the fear of positive evaluation theory (Weeks et al., 2008). Individuals with social anxiety may rapidly attend to positive evaluation because it signals being pulled further into an anxious situation. The depression bias toward sad faces was marginal but provides some support for the cognitive perspective that attentional vigilance for depressive content influences negative thoughts and mood. This research informs interventions such as attentional bias modification and cognitive-behavioral therapy.https://digitalcommons.odu.edu/gradposters2022_sciences/1006/thumbnail.jp
Constant-time solution to the Global Optimization Problem using Bruschweiler's ensemble search algorithm
A constant-time solution of the continuous Global Optimization Problem (GOP)
is obtained by using an ensemble algorithm. We show that under certain
assumptions, the solution can be guaranteed by mapping the GOP onto a discrete
unsorted search problem, whereupon Bruschweiler's ensemble search algorithm is
applied. For adequate sensitivities of the measurement technique, the query
complexity of the ensemble search algorithm depends linearly on the size of the
function's domain. Advantages and limitations of an eventual NMR implementation
are discussed.Comment: 14 pages, 0 figure
Flow properties of driven-diffusive lattice gases: theory and computer simulation
We develop n-cluster mean-field theories (0 < n < 5) for calculating the flow
properties of the non-equilibrium steady-states of the Katz-Lebowitz-Spohn
model of the driven diffusive lattice gas, with attractive and repulsive
inter-particle interactions, in both one and two dimensions for arbitrary
particle densities, temperature as well as the driving field. We compare our
theoretical results with the corresponding numerical data we have obtained from
the computer simulations to demonstrate the level of accuracy of our
theoretical predictions. We also compare our results with those for some other
prototype models, notably particle-hopping models of vehicular traffic, to
demonstrate the novel qualitative features we have observed in the
Katz-Lebowitz-Spohn model, emphasizing, in particular, the consequences of
repulsive inter-particle interactions.Comment: 12 RevTex page
Neoclassical transport of tungsten ion bundles in total-f neoclassical gyrokinetic simulations of a whole-volume JET-like plasma
Neoclassical gyrokinetic simulations including tungsten impurities are
carried out using multiple gyrokinetic bundles to model the many charge states
of tungsten ions present in the whole-volume of a model H-mode plasma in JET
geometry. A gyrokinetic bundle regroups tungsten ions of similar charge
together in order to decrease the computational cost. The initial radial shape
of the bundles and their individual charges are deduced from a coronal
approximation and from quasi-neutrality of the plasma. Low-Z tungsten ions move
radially inward from SOL into the core region, whereas high-Z tungsten ions
move radially outwardly from the core and inwardly from the separatrix. These
fluxes lead to an accumulation of tungsten in the pedestal top of our test
case. This organization of the fluxes cannot be captured by a single
tungsten-ion simulation. Large up/down poloidal asymmetries of tungsten form in
the pedestal and strongly influence the direction of these neoclassical fluxes.
Future implementation of atomic interactions between bundles is discussed.Comment: 11 pages, 11 figure
Sex chromosome positions in human interphase nuclei as studied by in situ hybridization with chromosome specific DNA probes
Two cloned repetitive DNA probes, pXBR and CY1, which bind preferentially to specific regions of the human X and Y chromosome, respectively, were used to study the distribution of the sex chromosomes in human lymphocyte nuclei by in situ hybridization experiments. Our data indicate a large variability of the distances between the sex chromosomes in male and female interphase nuclei. However, the mean distance observed between the X and Y chromosome was significantly smaller than the mean distance observed between the two X-chromosomes. The distribution of distances determined experimentally is compared with three model distributions of distances, and the question of a non-random distribution of sex chromosomes is discussed. Mathematical details of these model distributions are provided in an Appendix to this paper. In the case of a human translocation chromosome (XqterXp22.2::Yq11Y qter) contained in the Chinese hamster x human hybrid cell line 445 x 393, the binding sites of pXBR and CY1 were found close to each other in most interphase nuclei. These data demonstrate the potential use of chromosome-specific repetitive DNA probes to study the problem of interphase chromosome topography
A review of High Performance Computing foundations for scientists
The increase of existing computational capabilities has made simulation
emerge as a third discipline of Science, lying midway between experimental and
purely theoretical branches [1, 2]. Simulation enables the evaluation of
quantities which otherwise would not be accessible, helps to improve
experiments and provides new insights on systems which are analysed [3-6].
Knowing the fundamentals of computation can be very useful for scientists, for
it can help them to improve the performance of their theoretical models and
simulations. This review includes some technical essentials that can be useful
to this end, and it is devised as a complement for researchers whose education
is focused on scientific issues and not on technological respects. In this
document we attempt to discuss the fundamentals of High Performance Computing
(HPC) [7] in a way which is easy to understand without much previous
background. We sketch the way standard computers and supercomputers work, as
well as discuss distributed computing and discuss essential aspects to take
into account when running scientific calculations in computers.Comment: 33 page
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