Gas Sensing Properties of Metal Oxide Nanostructured Heterojunctions

Engineering: 2nd Place (The Ohio State University Denman Undergraduate Research Forum)Titanium dioxide (TiO2) has demonstrated great potential for resistive-type gas sensors used to detect hydrocarbons and volatile organic compounds (VOC). Two parameters which affect the sensitivity of gas sensors is the surface area of the sensing material and interfacial potentials. This experiment is exploring the VOC selectivity and gas-sensing ability of TiO2 aerogel, the highest surface area TiO2 – based material, and metal oxide powders (MOX) containing single crystalline TiO2 nanorods. Nanorods are high surface area structures which alter the potential at surface interfaces. The nanorod structures are hydrothermally grown directly onto the powders with the use of a microwave synthesis system. These hybrid powders are then used to fabricate sensors which are tested in ethanol and acetone saturated air. Thus far, commercial grade TiO2, SnO2, NiO, and CoO powders and TiO2 aerogel have been used for sensor fabrication. Initial results indicate that the response of aerogel-based sensors is highly dependent upon the quality of the aerogel. Preliminary tests have also shown that the presence of nanorods appreciably increases the response of the sensors to ethanol and acetone saturated air. The SnO2 hybrid (containing nanorods) and CoO hybrid sensors show promise for be selective towards ethanol. Selectivity towards ethanol or acetone would allow the sensor to be used as a tool for preemptive diagnoses of diseases, such as diabetes. It has been found that patients with certain diseases possess elevated concentrations of specific VOC’s in their breath. There has only been limited success in developing a sensor which is sensitive to either acetone or ethanol, two of the main VOC’s used for diagnosis. The relationship between a sensor’s response, selectivity, and surface interface composition is being analyzed. Future work includes analyzing the relationship between temperature and response and fabricating sensors made of mixed MOX powders, instead of hydrothermal compositing.The Ohio State University, Department of Materials Science and EngineeringAcademic Major: Materials Science and Engineerin

Dark-matter electric and magnetic dipole moments

We consider the consequences of a neutral dark-matter particle with a nonzero electric and/or magnetic dipole moment. Theoretical constraints, as well as constraints from direct searches, precision tests of the standard-model, the cosmic microwave background and matter power spectra, and cosmic gamma rays, are included. We find that a relatively light particle with mass between an MeV and a few GeV and an electric or magnetic dipole as large as ~3 x 10 to the -16 e cm (roughly 1.6 x 10 to the -5 μB) satisfies all experimental and observational bounds. Some of the remaining parameter space may be probed with forthcoming more sensitive direct searches and with the Gamma-Ray Large Area Space Telescope

Towards wide-bandwidth ultra-flat FOPAs

Fibre optical parametric amplifiers (FOPAs) offer the potential for high gain and >100 nm bandwidth at arbitrary wavelengths for increased transmission capacity. We will cover the main principles of the FOPA and discuss our approach to obtaining broad flat gain and performance improvement via simultaneous Raman amplification

Raman-Generated Pump and Its Use for Parametric Amplification and Phase Conjugation

We demonstrate the use of high gain Raman amplification for generating a high power pump for use within a fibre optical parametric amplifier and an optical phase conjugator showing potential for application across the entire low loss fibre transmission window

G254 undergraduate experiment

This paper describes the experiments on payload G254. Each experiment is accommodated in a spacepak and six experiments fly in a full canister. One of the experiments will be housed in a new Isospacepak structure, which will be described briefly. Five of the six experiments have dedicated controllers. The objective of each experiment is discussed. In addition, the operational scenario is provided

1THz-bandwidth polarization-diverse optical phase conjugation of 10x114Gb/s DP-QPSK WDM signals

Polarization diverse optical phase conjugation of a 1THz spectral-band 1.14Tb/s DP-QPSK WDM multiplex is demonstrated for the first time, showing a worst case Q2 penalty of 0.9dB over all conjugate wavelengths, polarizations and OSNR

Reduction of Nonlinear Intersubcarrier Intermixing in Coherent Optical OFDM by a Fast Newton-Based Support Vector Machine Nonlinear Equalizer

A fast Newton-based support vector machine (N-SVM) nonlinear equalizer (NLE) is experimentally demonstrated, for the first time, in 40 Gb/s 16-quadrature amplitude modulated coherent optical orthogonal frequency division multiplexing at 2000 km of transmission. It is shown that N-SVM-NLE extends the optimum launched optical power by 2 dB compared to the benchmark Volterra-based NLE. The performance improvement by N-SVM is due to its ability of tackling both deterministic fiber-induced nonlinear effects and the interaction between nonlinearities and stochastic noises (e.g., polarization-mode dispersion). An N-SVM is more tolerant to intersubcarrier nonlinear crosstalk effects than Volterra-based NLE, especially when applied across all subcarriers simultaneously. In contrast to the conventional SVM, the proposed algorithm is of reduced classifier complexity offering lower computational load and execution time. For a low C-parameter of 4 (a penalty parameter related to complexity), an execution time of 1.6 s is required for N-SVM to effectively mitigate nonlinearities. Compared to conventional SVM, the computational load of N-SVM is ∼6 times lower

Experimental demonstration of data-dependent pilot-aided phase noise estimation for CO-OFDM

We demonstrate a novel phase noise estimation scheme for CO-OFDM, in which pilot subcarriers are deliberately correlated to the data subcarriers. This technique reduces the overhead by a factor of 2

A recursive microfluidic platform to explore the emergence of chemical evolution

We propose that a chemically agnostic approach to explore the origin of life, using an automated recursive platform based on droplet microfluidics, could be used to induce artificial chemical evolution by iterations of growth, speciation, selection, and propagation. To explore this, we set about designing an open source prototype of a fully automated evolution machine, comprising seven modules. These modules are a droplet generator, droplet transfer, passive and active size sorting, splitter, incubation chamber, reservoir, and injectors, all run together via a LabVIEW(TM) program integration system. Together we aim for the system to be used to drive cycles of droplet birth, selection, fusion, and propagation. As a proof of principle, in addition to the working individual modules, we present data showing the osmotic exchange of glycylglycine containing and pure aqueous droplets, showing that the fittest droplets exhibit higher osomolarity relative to their neighbours, and increase in size compared to their neighbours. This demonstrates the ability of our platform to explore some different physicochemical conditions, combining the efficiency and unbiased nature of automation with our ability to select droplets as functional units based on simple criteria

Exceeding the nonlinear-shannon limit using Raman laser based amplification and optical phase conjugation

We demonstrate that a combination of Raman laser based amplification and optical phase conjugation enables transmission beyond the nonlinear-Shannon limit. We show nonlinear compensation of 7x114Gbit/s DP-QPSK channels, increasing system reach by 30%