5,886 research outputs found
Numerical study on run-up heights of solitary wave with hydrodynamic pressure model
For many shallow water flows, it is sufficient to consider the depth-averaged equations, referred as the shallow water equations, which are two-dimensional in the horizontal plane, since the length scale of the vertical direction is much smaller than that of the horizontal directions. Assuming that the pressure distribution is hydrostatic, the mathematical formulation and its numerical implementation are considerably simplified. In this study, a numerical model is newly developed to investigate various free surface fl ow problems. The governing equations are the Navier???Stokes equations with the pressure decomposed into the sum of a hydrostatic and a hydrodynamic components. The equation for the free surface movement is a depth???averaged continuity equation which is a free surface equation. These governing equations are simultaneously solved by using a finite difference method with a semi???implicit method and fractional step method. At the first step, the vertical momentum equations are discretized by using an implicit method over the vertical direction. In the second step, the discrete horizontal momentum equations are projected on to the free surface equation. Finally, the hydrodynamic pressure and final velocity field are calculated. To verify the accuracy and stability, the present numerical model is applied to move practical problems such as the run???up process of solitary waves attacking a circular island. The numerically obtained maximum run???up heights around a circular island are compared with available laboratory measurements. A very reasonable agreement is observed
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Biocompatibility of SLS-Formed Calcium Phosphate Implants
A method for fabricating artificial calcium phosphate bone implants by the Selective Laser
Sintering (SLS) process has been developed that can fabricate complex and delicate
calcium phosphate bone facsimiles from a variety of data inputs including Computed
Tomography(CT) files (1). This paper discusses two in vivo biocompatibility studies of
SLS-formed calcium phosphate implants in both rabbits and dogs. Histologic analysis
shows a high degree of biocompatibility and bone ingrowth in both studies.Mechanical Engineerin
Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK
Subglacial drainage systems exert a major control on basal-sliding rates and glacier dynamics. However, comparatively few studies have examined the sedimentary record of subglacial drainage. This is due to the paucity of modern analogues, the limited recognition and preservation of upper flow regime deposits within the geological record, and the difficulty of distinguishing subglacial meltwater deposits from other meltwater sediments (e.g. glacier outburst flood deposits). Within this study, the sedimentological and structural evolution of a subglacial to subaerial (ice-marginal/proglacial) drainage system is examined. Particular emphasis is placed upon the genetic development and preservation of upper flow regime bedforms and specifically recognising them within a subglacial meltwater context. Facies are attributed to subglacial meltwater activity and record sedimentation within a confined, but progressively enlargening, subglacial channel system produced under dune to upper flow regime conditions. Bedforms include rare large-scale sinusoidal bedding with syn-depositional deformation produced by current-induced traction and shearing within the channel margins. Subglacial sedimentation culminated with the abrupt change to a more ephemeral drainage regime indicating channel-abandonment or a seasonal drainage regime. Retreat of the ice margin, led to the establishment of subaerial drainage with phases of sheet-flow punctuated by channel incision and anastomosing channel development under diurnal, ablation-related, seasonal discharge. The presence of extensive hydrofracture networks demonstrate that proglacial groundwater-levels fluctuated markedly and this may have influenced later overriding of the site by an ice stream
Owl and Lizard: Patterns of Head Pose and Eye Pose in Driver Gaze Classification
Accurate, robust, inexpensive gaze tracking in the car can help keep a driver
safe by facilitating the more effective study of how to improve (1) vehicle
interfaces and (2) the design of future Advanced Driver Assistance Systems. In
this paper, we estimate head pose and eye pose from monocular video using
methods developed extensively in prior work and ask two new interesting
questions. First, how much better can we classify driver gaze using head and
eye pose versus just using head pose? Second, are there individual-specific
gaze strategies that strongly correlate with how much gaze classification
improves with the addition of eye pose information? We answer these questions
by evaluating data drawn from an on-road study of 40 drivers. The main insight
of the paper is conveyed through the analogy of an "owl" and "lizard" which
describes the degree to which the eyes and the head move when shifting gaze.
When the head moves a lot ("owl"), not much classification improvement is
attained by estimating eye pose on top of head pose. On the other hand, when
the head stays still and only the eyes move ("lizard"), classification accuracy
increases significantly from adding in eye pose. We characterize how that
accuracy varies between people, gaze strategies, and gaze regions.Comment: Accepted for Publication in IET Computer Vision. arXiv admin note:
text overlap with arXiv:1507.0476
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