418 research outputs found
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Mulsemedia: State of the art, perspectives, and challenges
Mulsemedia-multiple sensorial media-captures a wide variety of research efforts and applications. This article presents a historic perspective on mulsemedia work and reviews current developments in the area. These take place across the traditional multimedia spectrum-from virtual reality applications to computer games-as well as efforts in the arts, gastronomy, and therapy, to mention a few. We also describe standardization efforts, via the MPEG-V standard, and identify future developments and exciting challenges the community needs to overcome
Virtual Shaping on NACA 0015 by Means of a High Momentum Coefficient Synthetic Jet
Results concerning flow control on a NACA 0015 airfoil using high power synthetic jets are presented for low incidences and for Reynolds numbers ranging from 132000 to 425000. The forcing was operated through a spanwise slit positioned near the leading edge at x/c=1.25% or at x/c=10% on the upper surface. Static pressure distribution measurements around the airfoil, wake surveys and smoke flow visualizations were performed. Pressure distributions were significantly modified around the injection location, showing an area of intense suction which increased the lift and strongly affected the drag. Flow visualizations highlighted that the intense suction was due to a virtual shaping effect caused by the formation of a recirculation bubble capable of displacing the streamlines. Low momentum deficits in the wake velocity distributions and, in certain conditions, jet-like flow was observed for the forced cases. Finally, a scaling law relating the bubble size to the forcing intensity is propose
Hairs on the cosmological horizon
We investigate the possibility of having hairs on the cosmological horizon.
The cosmological horizon shares similar properties of black hole horizons in
the aspect of having hairs on the horizons. For those theories admitting haired
black hole solutions, the nontrivial matter fields may reach and extend beyond
the cosmological horizon. For Q-stars and boson stars, the matter fields cannot
reach the cosmological horizon. The no short hair conjecture keeps valid,
despite the asymptotic behavior (de Sitter or anti-de Sitter) of black hole
solutions. We prove the no scalar hair theorem for anti-de Sitter black holes.
Using the Bekenstein's identity method, we also prove the no scalar hair
theorem for the de Sitter space and de Sitter black holes if the scalar
potential is convex.Comment: Revtex, no figures, 16 page
Modelling of friction stir welding of DH36 steel
A 3-D computational fluid dynamics (CFD) model
was developed to simulate the friction stir welding of 6-mm
plates of DH36 steel in an Eulerian steady-state framework.
The viscosity of steel plate was represented as a non-
Newtonian fluid using a flow stress function. The PCBN-WRe
hybrid tool was modelled in a fully sticking condition with the cooling system effectively represented as a negative heat flux. The model predicted the temperature distribution in the stirred zone (SZ) for six welding speeds including low, intermediate and
high welding speeds. The results showed higher asymmetry in
temperature for high welding speeds. Thermocouple data for the
high welding speed sample showed good agreement with the
CFD model result. The CFD model results were also validated
and compared against previous work carried out on the same
steel grade. The CFD model also predicted defects such as
wormholes and voids which occurred mainly on the advancing
side and are originated due to the local pressure distribution
between the advancing and retreating sides. These defects were
found to be mainly coming from the lack in material flow which
resulted from a stagnant zone formation especially at high tra-
verse speeds. Shear stress on the tool surface was found to in-
crease with increasing tool traverse speed. To produce a âsoundâ
weld, the model showed that the welding speed should remain
between 100 and 350 mm/min. Moreover, to prevent local melt-
ing, the maximum toolâs rotational speed should not exceed
550 RPM
Extensive marine-terminating ice sheets in Europe from 2.5 million years ago
Geometries of Early Pleistocene [2.58 to 0.78 million years (Ma) ago] ice sheets in northwest Europe are poorly constrained but are required to improve our understanding of past ocean-atmosphere-cryosphere coupling. Ice sheets are believed to have changed in their response to orbital forcing, becoming, from about 1.2 Ma ago, volumetrically larger and longer-lived. We present a multiproxy data set for the North Sea, extending to over a kilometer below the present-day seafloor, which demonstrates spatially extensive glaciation of the basin from the earliest Pleistocene. Ice sheets repeatedly entered the North Sea, south of 60°N, in water depths of up to ~250 m from 2.53 Ma ago and subsequently grounded in the center of the basin, in deeper water, from 1.87 Ma ago. Despite lower global ice volumes, these ice sheets were near comparable in spatial extent to those of the Middle and Late Pleistocene but possibly thinner and moving over slippery (low basal resistance) beds
Properties of a Yeast Cytochrome P-450-Containing Enzyme System which Catalyzes the Hydroxylation of Fatty Acids, Alkanes, and Drugs
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65977/1/j.1432-1033.1973.tb02948.x.pd
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