Optimum electrode configurations for fast ion separation in microfabricated surface ion traps

For many quantum information implementations with trapped ions, effective shuttling operations are important. Here we discuss the efficient separation and recombination of ions in surface ion trap geometries. The maximum speed of separation and recombination of trapped ions for adiabatic shuttling operations depends on the secular frequencies the trapped ion experiences in the process. Higher secular frequencies during the transportation processes can be achieved by optimising trap geometries. We show how two different arrangements of segmented static potential electrodes in surface ion traps can be optimised for fast ion separation or recombination processes. We also solve the equations of motion for the ion dynamics during the separation process and illustrate important considerations that need to be taken into account to make the process adiabatic

Single channel speech music separation using nonnegative matrix factorization and spectral masks

A single channel speech-music separation algorithm based on nonnegative matrix factorization (NMF) with spectral masks is proposed in this work. The proposed algorithm uses training data of speech and music signals with nonnegative matrix factorization followed by masking to separate the mixed signal. In the training stage, NMF uses the training data to train a set of basis vectors for each source. These bases are trained using NMF in the magnitude spectrum domain. After observing the mixed signal, NMF is used to decompose its magnitude spectra into a linear combination of the trained bases for both sources. The decomposition results are used to build a mask, which explains the contribution of each source in the mixed signal. Experimental results show that using masks after NMF improves the separation process even when calculating NMF with fewer iterations, which yields a faster separation process

Using audio and visual information for single channel speaker separation

This work proposes a method to exploit both audio and vi- sual speech information to extract a target speaker from a mix- ture of competing speakers. The work begins by taking an ef- fective audio-only method of speaker separation, namely the soft mask method, and modifying its operation to allow visual speech information to improve the separation process. The au- dio input is taken from a single channel and includes the mix- ture of speakers, where as a separate set of visual features are extracted from each speaker. This allows modification of the separation process to include not only the audio speech but also visual speech from each speaker in the mixture. Experimen- tal results are presented that compare the proposed audio-visual speaker separation with audio-only and visual-only methods us- ing both speech quality and speech intelligibility metrics

Incipient Separation in Shock Wave Boundary Layer Interactions as Induced by Sharp Fin

The incipient separation induced by the shock wave turbulent boundary layer interaction at the sharp fin is the subject of present study. Existing theories for the prediction of incipient separation, such as those put forward by McCabe (1966) and Dou and Deng (1992), can have thus far only predicting the direction of surface streamline and tend to over-predict the incipient separation condition based on the Stanbrook's criterion. In this paper, the incipient separation is firstly predicted with Dou and Deng (1992)'s theory and then compared with Lu and Settles (1990)' experimental data. The physical mechanism of the incipient separation as induced by the shock wave/turbulent boundary layer interactions at sharp fin is explained via the surface flow pattern analysis. Furthermore, the reason for the observed discrepancy between the predicted and experimental incipient separation conditions is clarified. It is found that when the wall limiting streamlines behind the shock wave becomes\ aligning with one ray from the virtual origin as the strength of shock wave increases, the incipient separation line is formed at which the wall limiting streamline becomes perpendicular to the local pressure gradient. The formation of this incipient separation line is the beginning of the separation process. The effects of Reynolds number and the Mach number on incipient separation are also discussed. Finally, a correlation for the correction of the incipient separation angle as predicted by the theory is also given.Comment: 34 pages; 9 figure

Effect of inter-sample spacing constraint on spectrum estimation with irregular sampling

A practical constraint that comes in the way of spectrum estimation of a continuous time stationary stochastic process is the minimum separation between successively observed samples of the process. When the underlying process is not band-limited, sampling at any uniform rate leads to aliasing, while certain stochastic sampling schemes, including Poisson process sampling, are rendered infeasible by the constraint of minimum separation. It is shown in this paper that, subject to this constraint, no point process sampling scheme is alias-free for the class of all spectra. It turns out that point process sampling under this constraint can be alias-free for band-limited spectra. However, the usual construction of a consistent spectrum estimator does not work in such a case. Simulations indicate that a commonly used estimator, which is consistent in the absence of this constraint, performs poorly when the constraint is present. These results should help practitioners in rationalizing their expectations from point process sampling as far as spectrum estimation is concerned, and motivate researchers to look for appropriate estimators of bandlimited spectra

Effects of ultrasonic waves on enhancement of relative volatilities in methanol-water mixtures

The application of ultrasonic wave in various fields including separation process has increased predominantly. This paper reports the practicability of using ultrasonic wave to enhance separation of binary mixtures by distillation. The binary mixture utilized was methanol-water. The effect of different ultrasonic intensity at 50, 100, 200 and 250 W/A.cm2 with frequency of 40 kHz to vapor-liquid equilibrium (VLE) of methanol-water was investigated to obtain the most suitable operating intensity. Experimental studies were also carried out to investigate the frequency effect (25 and 68 kHz) to VLE data. It was found that the use of ultrasonic wave enhanced the separation process by increasing the relative volatility of components. The highest average relative volatility of methanol-water at 29.413 was obtained from experimental study using intensity 200 W/A.cm2 and frequency of 25 kHz. The changes in relative volatility and VLE were caused by cavitational activities and vacuum effect that occur during transmission of ultrasonic wave in liquid medium. The results from this study proved the practical feasibility of using ultrasonic wave to enhance separation of binary mixtures in distillation column