1,445 research outputs found
VLF/AC Withstand Testing at NEETRAC
Presented at IEEE PES Insulated Conductors Committee, Spring 2008 Meeting , St. Petersburg, Florida, March 9-12, 2008. Copyright GTRC 2008.This material is based upon work supported by the Department of Energy under Award No DE-FC02-04CH1237
The Role of Degassing in XLPE Power Cable Manufacture
This paper appears in: Electrical Insulation Magazine, IEEE. ©2006 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.This article focuses on a range of elements critical to this process; form the fundamental chemistry, through computational and measurement techniques to the solutions that are in use today. Degassing contributes greatly to the quality of power cables by improving the certainty in electrical testing and improving the dielectric properties. To ensure that the degassing process delivers the expected benefits, it is important to measure and model the process by which the crosslinking byproducts are desorbed from the cable polymers. Weight loss and HPLC have shown themselves to be the most effective and practical measurement techniques
A concentration of centimeter-sized grains in the Oph IRS 48 dust trap
Azimuthally asymmetric dust distributions observed with ALMA in transition
disks have been interpreted as dust traps. We present VLA Ka band (34 GHz or
0.9 cm) and ALMA Cycle 2 Band 9 (680 GHz or 0.45 mm) observations at 0.2"
resolution of the Oph IRS 48 disk, which suggest that larger particles could be
more azimuthally concentrated than smaller dust grains, assuming an
axisymmetric temperature field or optically thin 680 GHz emission. Fitting an
intensity model to both data demonstrates that the azimuthal extent of the
millimeter emission is 2.3 times as wide as the centimeter emission,
marginally consistent with the particle trapping mechanism under the above
assumptions. The 34 GHz continuum image also reveals evidence for ionized gas
emission from the star. Both the morphology and the spectral index variations
are consistent with an increase of large particles in the center of the trap,
but uncertainties remain due to the continuum optical depth at 680 GHz.
Particle trapping has been proposed in planet formation models to allow dust
particles to grow beyond millimeter sizes in the outer regions of
protoplanetary disks. The new observations in the Oph IRS 48 disk provide
support for the dust trapping mechanism for centimeter-sized grains, although
additional data is required for definitive confirmation.Comment: Language editing and addition reference ALMA dat
Unlock your insight:employing a gamified app to engage manufacturers with servitization
This paper discusses the creation and dissemination of the gamified software application Unlock Your Insight. The app is based on an original workshop activity designed to engage representatives from the manufacturing industry with research into servitization. Both the workshop activity and the app encourage participants and users to reflect upon their organization’s competitive strategy; comparing their current and future visions in relation to the competitiveness of their product, price or package that they offer their customers. We argue that the gamification and digitalization of the activity allowed servitization research to be disseminated further and more quickly than previously possible
Patterns of neural response in scene-selective regions of the human brain are affected by low-level manipulations of spatial frequency
Neuroimaging studies have found distinct patterns of response to different categories of scenes. However, the relative importance of low-level image properties in generating these response patterns is not fully understood. To address this issue, we directly manipulated the low level properties of scenes in a way that preserved the ability to perceive the category. We then measured the effect of these manipulations on category-selective patterns of fMRI response in the PPA, RSC and OPA. In Experiment 1, a horizontal-pass or vertical-pass orientation filter was applied to images of indoor and natural scenes. The image filter did not have a large effect on the patterns of response. For example, vertical- and horizontal-pass filtered indoor images generated similar patterns of response. Similarly, vertical- and horizontal-pass filtered natural scenes generated similar patterns of response. In Experiment 2, low-pass or high-pass spatial frequency filters were applied to the images. We found that image filter had a marked effect on the patterns of response in scene-selective regions. For example, low-pass indoor images generated similar patterns of response to low-pass natural images. The effect of filter varied across different scene-selective regions, suggesting differences in the way that scenes are represented in these regions. These results indicate that patterns of response in scene-selective regions are sensitive to the low-level properties of the image, particularly the spatial frequency content
Resolved gas cavities in transitional disks inferred from CO isotopologues with ALMA
Transitional disks around young stars are promising candidates to look for
recently formed, embedded planets. Planet-disk interaction models predict that
planets clear a gap in the gas while trapping dust at larger radii. Other
physical mechanisms could be responsible for cavities as well. Previous
observations have revealed that gas is still present inside these cavities, but
the spatial distribution of this gas remains uncertain. We present high spatial
resolution observations with the Atacama Large Millimeter/submillimeter Array
(ALMA) of 13CO and C18O lines of four well-studied transitional disks. The
observations are used to set constraints on the gas surface density,
specifically cavity size and density drop inside the cavity. The
physical-chemical model DALI is used to analyze the gas images of SR21,
HD135344B, DoAr44 and IRS48. The main parameters of interest are the size,
depth and shape of the gas cavity. CO isotope-selective photodissociation is
included to properly constrain the surface density in the outer disk from C18O
emission. The gas cavities are up to 3 times smaller than those of the dust in
all four disks. Model fits indicate that the surface density inside the gas
cavities decreases by a factor of 100-10000 compared with the surface density
profile derived from the outer disk. A comparison with an analytical model of
gap depths by planet-disk interaction shows that the disk viscosities are
likely low, with a<1E-3 for planet masses <10 MJup. The resolved measurements
of the gas and dust in transition disk cavities support the predictions of
models that describe how planet-disk interactions sculpt gas disk structures
and influence the evolution of dust grains. These observed structures strongly
suggest the presence of giant planetary companions in transition disk cavities,
although at smaller orbital radii than is typically indicated from the dust
cavity radii alone.Comment: Accepted by A&A; version after language-editin
Connectopic mapping techniques do not reflect functional gradients in the brain
Functional gradients, in which response properties change gradually across a brain region, have been proposed as a key organising principle of the brain. Recent studies using both resting-state and natural viewing paradigms have indicated that these gradients may be reconstructed from functional connectivity patterns via “connectopic mapping” analyses. However, local connectivity patterns may be confounded by spatial autocorrelations artificially introduced during data analysis, for instance by spatial smoothing or interpolation between coordinate spaces. Here, we investigate whether such confounds can produce illusory connectopic gradients. We generated datasets comprising random white noise in subjects’ functional volume spaces, then optionally applied spatial smoothing and/or interpolated the data to a different volume or surface space. Both smoothing and interpolation induced spatial autocorrelations sufficient for connectopic mapping to produce both volume- and surface-based local gradients in numerous brain regions. Furthermore, these gradients appeared highly similar to those obtained from real natural viewing data, although gradients generated from real and random data were statistically different in certain scenarios. We also reconstructed global gradients across the whole-brain – while these appeared less susceptible to artificial spatial autocorrelations, the ability to reproduce previously reported gradients was closely linked to specific features of the analysis pipeline. These results indicate that previously reported gradients identified by connectopic mapping techniques may be confounded by artificial spatial autocorrelations introduced during the analysis, and in some cases may reproduce poorly across different analysis pipelines. These findings imply that connectopic gradients need to be interpreted with caution
- …