1,759 research outputs found
GAMER with out-of-core computation
GAMER is a GPU-accelerated Adaptive-MEsh-Refinement code for astrophysical
simulations. In this work, two further extensions of the code are reported.
First, we have implemented the MUSCL-Hancock method with the Roe's Riemann
solver for the hydrodynamic evolution, by which the accuracy, overall
performance and the GPU versus CPU speed-up factor are improved. Second, we
have implemented the out-of-core computation, which utilizes the large storage
space of multiple hard disks as the additional run-time virtual memory and
permits an extremely large problem to be solved in a relatively small-size GPU
cluster. The communication overhead associated with the data transfer between
the parallel hard disks and the main memory is carefully reduced by overlapping
it with the CPU/GPU computations.Comment: 4 pages, 4 figures, conference proceedings of IAU Symposium 270 (eds.
Alves, Elmegreen, Girart, Trimble
Parylene-HT-based electret rotor generator
A new micro power generator with parylene HT electret rotor is made. This generator uses parylene HT as a new electret material with a much superior charge density compared to teflon and CYTOP. The highest surface potential observed is 204.58 V/mum, equivalent to a surface charge density of 3.69 mC/m^2. The generator uses an electret rotor. The rotor is a piece of PEEK insulator block coated with a layer of corona-charged parylene HT. Both output electrodes are on the stator. The generator produces 17.98 ĀµW with 80MĪ© load at 50Hz and 7.77 ĀµW with an 800MĪ© load at 10Hz
Parylene-based electret power generators
n electret power generator is developed using a new electret made of a charged parylene HTĀ® thin-film polymer. Here, parylene HTĀ® is a room-temperature chemical-vapor-deposited thin-film polymer that is MEMS and CMOS compatible. With corona charge implantation, the surface charge density of parylene HTĀ® is measured as high as 3.69 mC m^ā2. Moreover, it is found that, with annealing at 400 Ā°C for 1 h before charge implantation, both the long-term stability and the high-temperature reliability of the electret are improved. For the generator, a new design of the stator/rotor is also developed. The new micro electret generator does not require any sophisticated gap-controlling structure such as tethers. With the conformal coating capability of parylene HTĀ®, it is also feasible to have the electret on the rotors, which is made of either a piece of metal or an insulator. The maximum power output, 17.98 ĀµW, is obtained at 50 Hz with an external load of 80 MĪ©. For low frequencies, the generator can harvest 7.7 ĀµW at 10 Hz and 8.23 ĀµW at 20 Hz
Vortex Turbulence in Linear Schroedinger Wave Mechanics
Quantum turbulence that exhibits vortex creation, annihilation and
interactions is demonstrated as an exact solution of the time-dependent,
free-particle Schr\"odinger equation evolved from a smooth random-phased
initial condition. Relaxed quantum turbulence in 2D and 3D exhibits universal
scaling in the steady-state energy spectrum as k-1 in small scales. Due to the
lack of dissipation, no evidence of the Kolmogorov-type forward energy cascade
in 3D or the inverse energy cascade in 2D is found, but the rotational and
potential flow components do approach equi-partition in the scaling regime. In
addition, the 3D vortex line-line correlation exhibits universal behaviour,
scaled as \Deltar^-2, where \Deltar is the separation between any two vortex
line elements, in fully developed turbulence. We also show that the quantum
vortex is not frozen to the matter, nor is the vortex motion induced by other
vortices via Biot-Savart's law. Thus, the quantum vortex is actually a
nonlinear wave, propagating at a speed very different from a classical vortex.Comment: 9 pages, 14 figure
A New Perspective for Shuttlecock Hitting Event Detection
This article introduces a novel approach to shuttlecock hitting event
detection. Instead of depending on generic methods, we capture the hitting
action of players by reasoning over a sequence of images. To learn the features
of hitting events in a video clip, we specifically utilize a deep learning
model known as SwingNet. This model is designed to capture the relevant
characteristics and patterns associated with the act of hitting in badminton.
By training SwingNet on the provided video clips, we aim to enable the model to
accurately recognize and identify the instances of hitting events based on
their distinctive features. Furthermore, we apply the specific video processing
technique to extract the prior features from the video, which significantly
reduces the learning difficulty for the model. The proposed method not only
provides an intuitive and user-friendly approach but also presents a fresh
perspective on the task of detecting badminton hitting events. The source code
will be available at
https://github.com/TW-yuhsi/A-New-Perspective-for-Shuttlecock-Hitting-Event-Detection
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