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Background information on neutron flux for an advanced high-flux reactor
This paper assumes a large D/sub 2/O reflector equipped with cold source(s), a hot source, and with a peak thermal flux in the reflector of phi/sub 0/ = 5 x 10/sup 15/ ncm/sup -2/ sec/sup -1/. The flux distributions for thermal, cold, and hot beams are estimated. The equations required to calculate neutron intensities delivered by beam tubes and guides are summarized and some expected intensities are given for the assumed 5 x 10/sup 15/ reactor. In addition, the equations needed to calculate monochromatic intensities delivered to the sample by a crystal monochromator are given
Electric Charge in Interaction with Magnetically Charged Black Holes
We examine the angular momentum of an electric charge e placed at rest
outside a dilaton black hole with magnetic charge Q. The electromagnetic
angular momentum which is stored in the electromagnetic field outside the black
hole shows several common features regardless of the dilaton coupling strength,
though the dilaton black holes are drastically different in their spacetime
structure depending on it. First, the electromagnetic angular momentum depends
on the separation distance between the two objects and changes monotonically
from eQ to 0 as the charge goes down from infinity to the horizon, if
rotational effects of the black hole are discarded. Next, as the black hole
approaches extremality, however, the electromagnetic angular momentum tends to
be independent of the distance between the two objects. It is then precisely
as in the electric charge and monopole system in flat spacetime. We
discuss why these effects are exhibited and argue that the above features are
to hold in widely generic settings including black hole solutions in theories
with more complicated field contents, by addressing the no hair theorem for
black holes and the phenomenon of field expulsion exhibited by extremal black
holes.Comment: 26 pages, 4 figures ; Typos are corrected and a reference is adde
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Neutron scattering evidence on Lifshitz behavior in MnP
The variation of q..-->.. in the fan phase of MnP was measured in order to test whether the para-ferro-fan triple point is a Lifshitz point. Along the para-fan phase boundary, q..-->.. continuously decreases as the triple point is approached, extrapolating to zero at a temperature in good agreement with other measurements of the triple point. The temperature dependence of q..-->.. along this phase boundary is in approximate agreement with theoretical expectations for Lifshitz point behavior. These data support the conclusion that the triple point is a Lifshitz point
Effects of bearing clearance on the chatter stability of milling process
In the present study, the influences of the bearing clearance, which is a common fault for machines, to the chatter stability of milling process are examined by using numerical simulation method. The results reveal that the presence of bearing clearance could make the milling process easier to enter the status of chatter instability and can shift the chatter frequency. In addition, the spectra analysis to vibration signals obtained under the instable milling processes show that the presence of bearing clearance could introduce more frequency components to the vibration responses but, however, under both the stable and instable milling processes, the generated frequency components will not violate the ideal spectra structures of the vibration responses of the milling process, which are usually characterized by the tooth passing frequency and its associated higher harmonics for the stable milling process and by the complex coupling of the tooth passing frequency and the chatter frequency for the instable milling process. This implies that, even under the case with bearing clearance fault, the stability of the milling process can still be determined by viewing the frequency spectra of the vibration responses. Moreover, the phenomena of the chatter frequency shift and the generation of more components provide potential ways to detect the bearing clearance in machines. (C) 2010 Elsevier Ltd. All rights reserved
Are Wikis and Weblogs an Appropriate Approach to Foster Collaboration, Reflection and Students’ Motivation?
Spin Fidelity for Three-qubit Greenberger-Horne-Zeilinger and W States Under Lorentz Transformations
Constructing the reduced density matrix for a system of three massive
spin particles described by a wave packet with Gaussian momentum
distribution and a spin part in the form of GHZ or W state, the fidelity for
the spin part of the system is investigated from the viewpoint of moving
observers in the jargon of special relativity. Using a numerical approach, it
turns out that by increasing the boost speed, the spin fidelity decreases and
reaches to a non-zero asymptotic value that depends on the momentum
distribution and the amount of momentum entanglement.Comment: 12pages, 2 figure
Development of a graphical user interface for automatic separation of human voice from Doppler ultrasound audio in diving experiments
Doppler ultrasound (DU) is used in decompression research to detect venous gas emboli in the precordium or subclavian vein, as a marker of decompression stress. This is of relevance to scuba divers, compressed air workers and astronauts to prevent decompression sickness (DCS) that can be caused by these bubbles upon or after a sudden reduction in ambient pressure. Doppler ultrasound data is graded by expert raters on the Kisman-Masurel or Spencer scales that are associated to DCS risk. Meta-analyses, as well as efforts to computer-automate DU grading, both necessitate access to large databases of well-curated and graded data. Leveraging previously collected data is especially important due to the difficulty of repeating large-scale extreme military pressure exposures that were conducted in the 70-90s in austere environments. Historically, DU data (Non-speech) were often captured on cassettes in one-channel audio with superimposed human speech describing the experiment (Speech). Digitizing and separating these audio files is currently a lengthy, manual task. In this paper, we develop a graphical user interface (GUI) to perform automatic speech recognition and aid in Non-speech and Speech separation. This constitutes the first study incorporating speech processing technology in the field of diving research. If successful, it has the potential to significantly accelerate the reuse of previously-acquired datasets. The recognition task incorporates the Google speech recognizer to detect the presence of human voice activity together with corresponding timestamps. The detected human speech is then separated from the audio Doppler ultrasound within the developed GUI. Several experiments were conducted on recently digitized audio Doppler recordings to corroborate the effectiveness of the developed GUI in recognition and separations tasks, and these are compared to manual labels for Speech timestamps. The following metrics are used to evaluate performance: the average absolute differences between the reference and detected Speech starting points, as well as the percentage of detected
Magnetic Order in YBaCuO Superconductors
Polarized and unpolarized neutron diffraction has been used to search for
magnetic order in YBaCuO superconductors. Most of the
measurements were made on a high quality crystal of YBaCuO. It
is shown that this crystal has highly ordered ortho-II chain order, and a sharp
superconducting transition. Inelastic scattering measurements display a very
clean spin-gap and pseudogap with any intensity at 10 meV being 50 times
smaller than the resonance intensity. The crystal shows a complicated magnetic
order that appears to have three components. A magnetic phase is found at high
temperatures that seems to stem from an impurity with a moment that is in the
- plane, but disordered on the crystal lattice. A second ordering occurs
near the pseudogap temperature that has a shorter correlation length than the
high temperature phase and a moment direction that is at least partly along the
c-axis of the crystal. Its moment direction, temperature dependence, and Bragg
intensities suggest that it may stem from orbital ordering of the -density
wave (DDW) type. An additional intensity increase occurs below the
superconducting transition. The magnetic intensity in these phases does not
change noticeably in a 7 Tesla magnetic field aligned approximately along the
c-axis. Searches for magnetic order in YBaCuO show no signal
while a small magnetic intensity is found in YBaCuO that is
consistent with c-axis directed magnetic order. The results are contrasted with
other recent neutron measurements.Comment: 11 pages with 10 figure
Non-parametric inference of impurity transport coefficients in the ASDEX Upgrade tokamak
We present a non-parametric inference of impurity transport coefficients by using charge exchange recombination spectroscopy measurements of Ne X, Ne VIII, O VIII, and C VI lines. Due to their close atomic numbers, neon, oxygen and carbon impurity ions are assumed to have the same diffusion coefficient D and convection velocity v. Unlike conventional techniques that modulate or perturb the impurity contents, we employ a quasi-stationary plasma with static impurity profiles. Since the ratio of v to D only describes the equilibrated profile of the sum of all impurity charge states, steady-state measurements can still decouple D and v if different charge states are simultaneously observed. We have formulated a non-parametric analysis framework based on the Bayesian probability theory and conducted transport coefficient measurements for a Type III ELMy H-mode plasma at ASDEX Upgrade. The charge exchange reactions with the background neutrals, which are known to affect the impurity charge state balance, are taken into account by introducing additional free parameters. While D at the pedestal is close to the neoclassical level ( < 1 m s-2), a large diffusion coefficient and a strong outward convection are inferred right inside the pedestal top.This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 and 2019–2020 under Grant Agreement No. 633053
Effect of dietary changes on the bacteriophage population in the rumen of sheep
Item does not contain fulltext4th Symposium on Gut Microbiology, 21 juni 200
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