BACKGROUND Recent revisions to the Sonsela Member of the Chinle Formation in Petrified Forest National Park have presented a three-part lithostratigraphic model based on unconventional correlations of sandstone beds. As a vertebrate faunal transition is recorded within this stratigraphic interval, these correlations, and the purported existence of a depositional hiatus (the Tr-4 unconformity) a...

When an object is dropped into a bed of fine, loosely packed sand, a surprisingly energetic jet shoots out of the bed. In this work we study the effect that boundaries have on the granular jet formation. We did this by (i) decreasing the depth of the sand bed and (ii) reducing the container diameter to only a few ball diameters. These confinements change the behavior of the ball inside the bed,...

A sample mission sequence is defined for a low earth orbit demonstration of Precision Formation Flying (PFF). Various guidance navigation and control strategies are discussed for use in the PFF experiment phases. A sample PFF experiment is implemented and tested in a realistic Hardware-in-the-Loop (HWIL) simulation using the Formation Flying Test Bed (FFTB) at NASA’s Goddard Space Flight Center.

A linear stability analysis of sediment transport by wind or water over an erodible bed shows that perturbations in a narrow range of wavenumbers are ampli ed, leading to the formation of ripples with a wavelength dependent on the roughness length of the bed. The roughness length is proportional to the grain size of the sand and the square of the excess shear velocity at the bed. We propose tha...

OBJECTIVE To share four Canadian cities' experiences with bed bug infestations and to explore public health roles in managing them. METHODS We summarize presentations from a workshop at the 2010 Canadian Public Health Association Conference which examined the re-emergence of bed bugs in Canada and compared management approaches of municipal and public health authorities in four large Canadian...

Surface roughness of laser powder bed fusion (L-PBF) printed overhang regions is a major contributor to deteriorated shape accuracy/surface quality. This study investigates the mechanisms behind evolution surface (Ra) in regions. The morphology result combination border track contour, adhesion, warp deformation, and dross formation, which strongly related angle (?). When 0° ? ? 15°, does not af...

The dynamics of river bed evolution are known to be notoriously complex affected by near-bed turbulence, the collective motion of clusters of particles of different sizes, and the formation of bedforms and other large-scale features. In this paper, we present the results of a study aiming to quantify the inherent nonlinearity and complexity in gravel bed dynamics. The data analyzed are bed elev...

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Liquid injection in fluidized beds is used to add reactants or improve the heat management reactor. This will increase complexity of reactor due formation agglomerates. In this work effect on particle temperature distribution a bed porous particles determined experimentally using image velocimetry and infra-red thermography. The main property influencing specific surface area. addition, porosit...