Showing papers by "Bruce E. Gnade published in 2016"

Analysis of the Multichannel WDM-VLC Communication System

Abstract: Visible light communication (VLC) systems can achieve a higher data rate by increasing the number of channels using wavelength division multiplexing (WDM) technology. In this paper, we investigate the maximum number of channels and possible data rate in a WDM-VLC system based on light emitting diode (LED). Channel crosstalk from the spectral overlap of LEDs is analyzed by modeling LED spectra and the formula for crosstalk is derived from VLC link, including optical filter transmittance and detector spectral response. An experimental setup with different wavelength of LEDs is used to confirm the validity of the crosstalk analysis. The number of channels and data rate are determined by the SNR, including signal power, channel crosstalk, and detector noise. The results indicate that for indoor illumination standard with on – off keying modulation and 33 nm channel spacing to achieve a BER of $10^{- 6}$ , the maximum and optimal numbers of channels are 12 and 10, respectively. Additionally, the achievable data rate is 5.1 Gb/s which is about 9.3 times than that of the single channel system.

Novel disposable microelectrode array for cultured neuronal network recording exhibiting equivalent performance to commercially available arrays

Abstract: Microelectrode arrays (MEAs) enable non-invasive recording of supra-threshold signals, i.e. action potentials or spikes, from a variety of cultured electrically active cells. While this label-free technology has been shown to be useful for pharmacological and toxicological studies, a major limitation has been the reliance on expensive recording substrates that have been manufactured with the intent of re-use. Prior work by our group has demonstrated an approach for fabricating MEAs using conventional liquid crystal display manufacturing techniques. Here, we describe and characterize the UT Dallas planar MEA which is fabricated with low cost materials and processes. We compare the performance of the UT Dallas MEAs, which consist of exposed gold microelectrodes with patterned parylene insulation over traces, with well-established commercially available MEAs using cultured murine cortical networks. Detailed electrophysiological comparisons show virtually identical performance between MEA types with respect to network metrics including recording yield across the array, network spike rate and burst rate, and virtually identical pharmacological responses to a diverse set of neuropharmacological agents.

Thin film CdTe based neutron detectors with high thermal neutron efficiency and gamma rejection for security applications

Abstract: Solid-state neutron detectors offer an alternative to 3He based detectors, but suffer from limited neutron efficiencies that make their use in security applications impractical. Solid-state neutron detectors based on single crystal silicon also have relatively high gamma-ray efficiencies that lead to false positives. Thin film polycrystalline CdTe based detectors require less complex processing with significantly lower gamma-ray efficiencies. Advanced geometries can also be implemented to achieve high thermal neutron efficiencies competitive with silicon based technology. This study evaluates these strategies by simulation and experimentation and demonstrates an approach to achieve >10% intrinsic efficiency with <10−6 gamma-ray efficiency.