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Freeform Fabrication of Ti3SiC2 Structures
This paper introduces a three-stage process to fabricate highly dense Ti3SiC2 structures. The
properties of Ti3SiC2 material, the synthesis of the ceramic powder, the procedure involved in
the 3-stage fabrication process and the preliminary results on fabricating fully dense Ti3SiC2
structures are presented. The characterization and microstructure evaluation of the mechanical,
morphological and structural properties covering the compressive strength, Vickers micro
hardness, damage tolerance, thermal shock, shrinkage and porosity of Ti3SiC2 structures printed
using the 3-stage process are presented.Mechanical Engineerin
Mixed symmetry superconductivity in two-dimensional Fermi liquids
We consider a 2D isotropic Fermi liquid with attraction in both and
channels and examine the possibility of a superconducting state with mixed
and symmetry of the gap function. We show that both in the weak coupling
limit and at strong coupling, a mixed symmetry state is realized in a
certain range of interaction. Phase transitions between the mixed and the pure
symmetry states are second order. We also show that there is no stable mixed
symmetry state at any coupling.Comment: 3 figures attached in uuencoded gzipped file
Demonstration of a 9 LP-mode transmission fiber with low DMD and loss
We experimentally demonstrate a 9 LP-mode (15 spatial modes) fiber with low DMD, confirmed by both time of flight and S2 measurements. Low loss (~0.2dB/km) is verified by OTDR measurement of the individual mode groups
Defect and anisotropic gap induced quasi-one-dimensional modulation of local density of states in YBaCuO
Motivated by recent angle-resolved photoemission spectroscopy (ARPES)
measurement that superconducting YBaCuO (YBCO) exhibits a
-symmetry gap, we show possible quasi-one-dimensional
modulations of local density of states in YBCO. These aniostropic gap and
defect induced stripe structures are most conspicuous at higher biases and
arise due to the nesting effect associated with a Fermi liquid. Observation of
these spectra by scanning tunneling microscopy (STM) would unify the picture
among STM, ARPES, and inelastic neutron scattering for YBCO.Comment: 4 pages, 4 figure
Ce and U speciation in wasteforms for thermal treatment of plutonium bearing wastes, probed by L3 edge XANES
X-ray absorption spectroscopy was applied to understand the speciation of elements relevant to the immobilisation and disposal of radioactive plutonium bearing wastes, utilizing Ce as a Pu surrogate. Ce L3 XANES (X-ray Absorption Near Edge Structure) characterisation of a crystallised glass material produced by cold crucible plasma vitrification, at demonstration scale, evidenced incorporation as Ce3+ within the glass phase, providing an important validation of laboratory scale studies. U and Ce L3 XANES investigation of brannerite ceramics, U0.9Ce0.1Ti2O6, synthesized under oxidizing, neutral and reducing conditions, established the charge compensation mechanism as incorporation of Ce3+ through formation of U5+ and/or U6+ In each of these examples, X-ray Absorption Spectroscopy has provided a pivotal understanding of element speciation in relation to the mechanism of incorporation within the host wasteform intended for geological disposal
Cubic String Field Theory in pp-wave Background and Background Independent Moyal Structure
We study Witten open string field theory in the pp-wave background in the
tensionless limit, and construct the N-string vertex in the basis which
diagonalizes the string perturbative spectrum. We found that the Witten
*-product can be viewed as infinite copies of the Moyal product with the same
noncommutativity parameter . Moreover, we show that this Moyal
structure is universal in the sense that, written in the string bit basis,
Witten's *-product for any background can always be given in terms of the
above-mentioned Moyal structure. We identify some projective operators in this
algebra that we argue to correspond to D-branes of the theory.Comment: Latex, 23 pages, reference adde
The regulation of peripheral metabolism by gut-derived hormones
Enteroendocrine cells lining the gut epithelium constitute the largest endocrine organ in the body and secrete over 20 different hormones in response to cues from ingested foods and changes in nutritional status. Not only do these hormones convey signals from the gut to the brain via the gut-brain axis, they also act directly on metabolically important peripheral targets in a highly concerted fashion to maintain energy balance and glucose homeostasis. Gut-derived hormones released during fasting tend to be orexigenic and have hyperglycaemic potential. Conversely, gut hormones secreted postprandially generally promote satiety and facilitate glucose clearance. Although some of the metabolic benefits conferred by bariatric surgeries have been ascribed to changes in the secretory profiles of various gut hormones, the therapeutic potential of the enteroendocrine system as a viable target against metabolic diseases remain largely underexploited, except for incretin-mimetics. This review provides a brief overview of the physiological importance and highlights the therapeutic potential of the following gut hormones: serotonin, glucose-dependent insulinotropic peptide, glucagon-like peptide 1, oxyntomodulin, peptide YY, insulin-like peptide 5, and ghrelin.Emily W.L. Sun, Alyce M. Martin, Richard L. Young and Damien J. Keatin
Moyal Representation of the String Field Star Product in the Presence of a B-background
In this paper we show that in the presence of an anti-symmetric tensor
-background, Witten's star algebra for open string fields persists to
possess the structure of a direct product of commuting Moyal pairs. The
interplay between the noncommutativity due to three-string overlap and that due
to the -background is our main concern. In each pair of noncommutative
directions parallel to the -background, the Moyal pairs mix string modes in
the two directions and are labeled, in addition to a continuous parameter, by
{\it two} discrete values as well. However, the Moyal parameters are
-dependent only for discrete pairs. We have also demonstrated the large-
contraction of the star algebra, with one of the discrete Moyal pairs dropping
out while the other giving rise to the center-of-mass noncommutative function
algebra.Comment: minor notation chang
Do You See What Eyes See? Implementing Inattentional Blindness
This paper presents a computational model of visual attention incorporating a cognitive imperfection known as inattentional blindness. We begin by presenting four factors that determine successful attention allocation: conspicuity, mental workload, expectation and capacity. We then propose a framework to study the effects of those factors on an unexpected object and conduct an experiment to measure the corresponding subjective awareness level. Finally, we discuss the application of a visual attention model for conversational agents
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