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Rapid Prototyping of Functional Three-Dimensional Microsolenoids and Electromagnets by High-Pressure Laser Chemical Vapor Deposition
Three-dimensional laser chemical vapor deposition (3D-LCVD) is an emerging process
which bridges the gap between various macro-scale rapid prototyping (RP) systems and microfabrication technologies. With the ability to deposit both metals and dielectrics 3D-LCVD
may be used to prototype integrated electromechanical components from sub-micron to centimeter scales. This technological niche is increasingly important with the ever-decreasing size
and sophistication of consumer and industrial products.
The objective of this work was the development of functional microsolenoids and electromagnets, using 3D-LCVD as the primary fabrication tool. High-aspect-ratio microsolenoids
have the potential to generate much greater magnetic-field densities than their thin-film counterparts,l and have many advantages when used as actuators in microelectromechanical systems (MEMS).2 3D-LCVD provides a means of fabricating such helical structures, with an
ease unparalleled by any lithographic or rapid prototyping process.Mechanical Engineerin
The first gamma-ray detection of the narrow-line Seyfert 1 FBQS J1644+2619
We report the discovery of gamma-ray emission from the narrow-line Seyfert 1
(NLSy1) galaxy FBQS J1644+2619 by the Large Area Telescope on board the Fermi
satellite. The Third Fermi LAT Source catalogue reports an unidentified
gamma-ray source, detected over the first four years of Fermi operation, 0.23
deg from the radio position of the NLSy1. Analysing 76 months of gamma-ray data
(2008 August 4 - 2014 December 31) we are able to better constrain the
localization of the gamma-ray source. The new position of the gamma-ray source
is 0.05 deg from FBQS J1644+2619, suggesting a spatial association with the
NLSy1. This is the sixth NLSy1 detected at high significance by Fermi-LAT so
far. Notably, a significant increase of activity was observed in gamma-rays
from FBQS J1644+2619 during 2012 July-October, and an increase of activity in
V-band was detected by the Catalina Real-Time Sky Survey in the same period.Comment: 6 pages, 2 figures. accepted for publication in Monthly Notices of
the Royal Astronomical Societ
Bipedal steps in the development of rhythmic behavior in humans
We contrast two related hypotheses of the evolution of dance: H1: Maternal bipedal walking influenced the fetal experience of sound and associated movement patterns; H2: The human transition to bipedal gait produced more isochronous/predictable locomotion sound resulting in early music-like behavior associated with the acoustic advantages conferred by moving bipedally in pace. The cadence of walking is around 120 beats per minute, similar to the tempo of dance and music. Human walking displays long-term constancies. Dyads often subconsciously synchronize steps. The major amplitude component of the step is a distinctly produced beat. Human locomotion influences, and interacts with, emotions, and passive listening to music activates brain motor areas. Across dance-genres the footwork is most often performed in time to the musical beat. Brain development is largely shaped by early sensory experience, with hearing developed from week 18 of gestation. Newborns reacts to sounds, melodies, and rhythmic poems to which they have been exposed in utero. If the sound and vibrations produced by footfalls of a walking mother are transmitted to the fetus in coordination with the cadence of the motion, a connection between isochronous sound and rhythmical movement may be developed. Rhythmical sounds of the human mother locomotion differ substantially from that of nonhuman primates, while the maternal heartbeat heard is likely to have a similar isochronous character across primates, suggesting a relatively more influential role of footfall in the development of rhythmic/musical abilities in humans. Associations of gait, music, and dance are numerous. The apparent absence of musical and rhythmic abilities in nonhuman primates, which display little bipedal locomotion, corroborates that bipedal gait may be linked to the development of rhythmic abilities in humans. Bipedal stimuli in utero may primarily boost the ontogenetic development. The acoustical advantage hypothesis proposes a mechanism in the phylogenetic development
Effects of a nonadiabatic wall on supersonic shock/boundary-layer interactions
Direct numerical simulations are employed to investigate a shock wave impinging on a turbulent boundary layer at free-stream Mach number M=2.28 with different wall thermal conditions, including adiabatic, cooled, and heated, for a wide range of deflection angles. It is found that the thermal boundary condition at the wall has a large effect on the size of the interaction region and on the level of pressure fluctuations. The distribution of the Stanton number shows a good agreement with prior experimental studies and confirms the strong heat transfer and complex pattern within the interaction region. An effort was also made to describe the unsteady features of the flow by means of wall pressure and heat flux spectra. Numerical results indicate that the changes in the interaction length due to the wall thermal condition are mainly linked to the incoming boundary layer, which is in agreement with previous experimental studies
Lateral coherence properties of broad-area semiconductor quantum well lasers
The lateral coherence of broad-area lasers fabricated from a GaAs/GaAlAs graded index waveguide separate confinement and single quantum well heterostructure grown by molecular-beam epitaxy was investigated. These lasers exhibit a high degree of coherence along the junction plane, thus producing a stable and very narrow far field intensity distribution
An M-theory solution generating technique and SL(2,R)
In this paper we generalize the O(p+1,p+1) solution generating technique
(this is a method used to deform Dp-branes by turning on a NS-NS B-field) to
M-theory, in order to be able to deform M5-brane supergravity solutions
directly in eleven dimensions, by turning on a non zero three form A. We find
that deforming the M5-brane, in some cases, corresponds to performing certain
SL(2,R) transformations of the Kahler structure parameter for the three-torus,
on which the M5-brane has been compactified. We show that this new M-theory
solution generating technique can be reduced to the O(p+1,p+1) solution
generating technique with p=4. Further, we find that it implies that the open
membrane metric and generalized noncommutativity parameter are manifestly
deformation independent for electric and light-like deformations. We also
generalize the O(p+1,p+1) method to the type IIA/B NS5-brane in order to be
able to deform NS5-branes with RR three and two forms, respectively. In the
type IIA case we use the newly obtained solution generating technique and
deformation independence to derive a covariant expression for an open D2-brane
coupling, relevant for OD2-theory.Comment: 24 pages, Latex. v2:Sections 3.2 and 3.3 improved. v3:Some
clarifications added. Version published in JHE
Estimates of rates for dissociative recombination of NO + e via various mechanisms
We estimate rates for the dissociative recombination (DR) of NO +
e. Although accurate excited state potential energy curves for the excited
states of the neutral are not available, we estimate that the 1 {\Phi}
and the 1 {\Pi} states of the neutral may intersect the ground state
cation potential energy surface near its equilibrium geometry. Using fixed
nuclei scattering calculations we estimate the rate for direct DR via these
states and find it to be significant. We also perform approximate calculations
of DR triggered by the indirect mechanism, which suggest that the indirect DR
rate for NO is insignificant compared to the direct rate.Comment: Submitted to Phys Rev
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