Cross-waves induced by the vertical oscillation of a fully immersed vertical plate

Capillary waves excited by the vertical oscillations of a thin elongated plate below an air-water interface are analyzed using time-resolved measurements of the surface topography. A parametric instability is observed above a well defined acceleration threshold, resulting in a so-called cross-wave, a staggered wave pattern localized near the wavemaker and oscillating at half the forcing frequency. This cross-wave, which is stationary along the wavemaker but propagative away from it, is described as the superposition of two almost anti-parallel propagating parametric waves making a small angle of the order of $20^\mathrm{o}$ with the wavemaker edge. This contrasts with the classical Faraday parametric waves, which are exactly stationnary because of the homogeneity of the forcing. Our observations suggest that the selection of the cross-wave angle results from a resonant mechanism between the two parametric waves and a characteristic length of the surface deformation above the wavemaker.Comment: to appear in Physics of Fluid

Sparse Reconstruction-based Detection of Spatial Dimension Holes in Cognitive Radio Networks

In this paper, we investigate a spectrum sensing algorithm for detecting spatial dimension holes in Multiple Inputs Multiple Outputs (MIMO) transmissions for OFDM systems using Compressive Sensing (CS) tools. This extends the energy detector to allow for detecting transmission opportunities even if the band is already energy filled. We show that the task described above is not performed efficiently by regular MIMO decoders (such as MMSE decoder) due to possible sparsity in the transmit signal. Since CS reconstruction tools take into account the sparsity order of the signal, they are more efficient in detecting the activity of the users. Building on successful activity detection by the CS detector, we show that the use of a CS-aided MMSE decoders yields better performance rather than using either CS-based or MMSE decoders separately. Simulations are conducted to verify the gains from using CS detector for Primary user activity detection and the performance gain in using CS-aided MMSE decoders for decoding the PU information for future relaying.Comment: accepted for PIMRC 201

The Possibility of Determining the Level of Performance in the Faculty of Education at Kuwait University Using the ‘Balanced Scorecard’ from the Perspective of Faculty Members

This study aimed to identify the possibility of determining the level of performance in the Faculty of Education at Kuwait University using the ‘Balanced Scorecard’ from the point of view of faculty members. The study used the descriptive methodology through a tool which was applied to (98) faculty members in the College of Education at Kuwait University. The results showed that the ‘vision and action strategies’ have obtained an average performance, while the rest of the dimensions were of poor performance. There were statistically significant differences due to educational degree in favor of professors, and years of experience in favor of 21 years and above. The level of performance about the vision and action strategies can be predicted in the College of Education based on the level of performance using the ‘Balanced Scorecard’. The effect of the domain ‘the internal operations’ was statistically insignificant and was less influential on the ‘vision and action strategies’; while ‘the financial management’ was the highest in impact. In conclusion, the study proposed some important recommendations and suggestions

K-feldspar Sand Grain Rounding in Eolian and Subaqueous Transportation

This project’s aim is to compare the rounding of K-feldspar grains in eolian and subaqueous conditions. It was hypothesized that K-feldspar grains in a subaqueous environment are cushioned enough by surrounding water to prevent the rounding observed in eolian environments. The experiment was conducted by use of eolian and subaqueous simulations originally developed by Calvin Anderson for comparing muscovite flakes in these respective environments. It was expected that an eolian environment will produce rounded grains within a few weeks, and an aqueous environment will take a minimum of months to produce fully rounded grains. The resulting data from this project will shed some light on the depositional environments of K-feldspar-rich sandstones

Geologic Analysis of Ice Age Simulation Results

Ice ages are believed to have occurred at least 5 times in the past, with each glacial period lasting tens of thousands of years and interglacial periods lasting up to 400,000 years. It is hypothesized, however, that the Genesis Flood would have provided the conditions necessary to trigger an ice age within a few hundred years, that could account for the glacial deposits we find worldwide. This research project compared the output data from a 360-year ModelE2.1.2 run of an ice age simulation, to the geologic record of the last glacial maximum (LGM). The simulation was inputted with conditions based on Michael Oard’s proposed model for the flood causing the ice age

Temperature stability of intersubband transitions in AlN/GaN quantum wells

Temperature dependence of intersubband transitions in AlN/GaN multiple quantum wells grown with molecular beam epitaxy is investigated both by absorption studies at different temperatures and modeling of conduction-band electrons. For the absorption study, the sample is heated in increments up to $400^\circ$C. The self-consistent Schr\"odinger-Poisson modeling includes temperature effects of the band-gap and the influence of thermal expansion on the piezoelectric field. We find that the intersubband absorption energy decreases only by $\sim 6$ meV at $400^\circ$C relative to its room temperature value