Thermally stable low current consuming gallium and germanium chalcogenides for consumer and automotive memory applications

The phase change technology behind rewritable optical disks and the latest generation of electronic memories has provided clear commercial and technological advances for the field of data storage, by virtue of the many well known attributes, in particular scaling, cycling endurance and speed, that chalcogenide materials offer. While the switching power and current consumption of established germanium antimony telluride based memory cells are a major factor in chip design in real world applications, often the thermal stability of the device can be a major obstacle in the path to the full commercialisation. In this work we describe our research in material discovery and characterization for the purpose of identifying more thermally stable chalcogenides for applications in PCRAM

Young Corn Ear Addition Improves Some Nutrients and Lowering Glycemic Index of Chiffon Cake

The effects of partial replacement of wheat flour with young corn ear (YCE) on sensory properties and glycemic index (GI) of chiffon cake were investigated. Dried YCE was processed into powdered form and added in chiffon cake formulations to replace wheat flour partially at concentrations of 0 (control), 10%, 20% and 30%. Protein, ash and dietary fibre contents of chiffon cake added with YCE powder were increased in line with the levels of YCE used. Even though protein content of YCE-based cakes increased in line (13.3% to 15.7%) with the levels of YCE (10% to 30%), but there was no significant difference compared to control. Sensory evaluation results indicate that partial replacement of wheat flour with up to 10% is satisfactory as compared to other levels of wheat flour replacement. Interestingly, addition of YCE at 10% to partially replace wheat flour resulted in reduction of postprandial blood glucose response. The GI value for chiffon cake added with YCE was 49 lower than control cake which recorded GI value at 60. In conclusion, novel food ingredient of YCE can be incorporated in selected bakery products to enhance nutritional composition while at the same time help in reducing the GI value. Further investigation on the addition of YCE into other bakery products in relation to nutrition and glycemic response effects can also be explored

Regulation of menaquinone production in Desulfovibrio vulgaris Hildenborough and Desulfovibrio desulfuricans strain G20 [abstract]

Abstract only availableMenaquinones are cytoplasmic membrane components that have important roles in electron transport for energy generation in anaerobic bacteria. A simple and sensitive protocol for the purification and quantification of menaquinones from the sulfate-reducing anaerobes Desulfovibrio vulgaris Hildenborough and Desulfovibrio desulfuricans strain G20 has been established. This method was used to determine whether differences occurred in menaquinone production in cells grown by fermentation when compared with those grown by respiration. Purified menaquinone extracts from both species were analyzed using thin-layer chromatography, UV absorption spectroscopy, and high-performance liquid chromatography. It was observed that each species possesses the same two menaquinones but the ratio between the two menaquinones differed in each species. The effects of alternate growth modes on the menaquinone content of the cells is being explored. Methods to further characterize and identify the two menaquinones is currently in progress

Acoustic properties of biodegradable composite micro-perforated panel (BC-MPP) made from kenaf fibre and polylactic acid (PLA)

This paper investigates the sound absorption of biodegradable composite micro-perforated panel (BC-MPP) made from kenaf fibre and biodegradable polymer known as polylactic acid (PLA). BC-MPP samples were made through conventional machining method such as mixing, drilling, and hot pressing process. Sound absorption of BC-MPP samples were measured by using impedance tube. The porosity and tensile strength of BC-MPP samples were determined by using porosity tester and universal testing machine respectively. The effects of material composition and air gap thickness behind the panel towards the sound absorption coefficient of BC-MPP samples along with the porosity and tensile strength of BC-MPP samples will be presented in this paper. Results indicate that the sound absorption coefficient of BC-MPP samples could be affected by the difference of composition percentage of kenaf fibre and PLA. The porosity of BC-MPP sample increases along with the increment of kenaf fibre composition. However, the increment of kenaf fibre composition causes the reduction of tensile strength of BC-MPP sample. As the air gap thickness behind the panel increases, the peak absorption of BC-MPP sample shifts nearer to lower frequency range. The maximum sound absorption coefficient of BC-MPP sample can be varied as well by altering the air gap thickness behind the panel

WSPEC: A waveguide filter-bank focal plane array spectrometer for millimeter wave astronomy and cosmology

Imaging and spectroscopy at (sub-)millimeter wavelengths are key frontiers in astronomy and cosmology. Large area spectral surveys with moderate spectral resolution (R=50-200) will be used to characterize large scale structure and star formation through intensity mapping surveys in emission lines such as the CO rotational transitions. Such surveys will also be used to study the SZ effect, and will detect the emission lines and continuum spectrum of individual objects. WSPEC is an instrument proposed to target these science goals. It is a channelizing spectrometer realized in rectangular waveguide, fabricated using conventional high-precision metal machining. Each spectrometer is coupled to free space with a machined feed horn, and the devices are tiled into a 2D array to fill the focal plane of the telescope. The detectors will be aluminum Lumped-Element Kinetic Inductance Detectors (LEKIDs). To target the CO lines and SZ effect, we will have bands at 135-175 GHz and 190-250 GHz, each Nyquist-sampled at R~200 resolution. Here we discuss the instrument concept and design, and successful initial testing of a WR10 (i.e. 90 GHz) prototype spectrometer. We recently tested a WR5 (180 GHz) prototype to verify that the concept works at higher frequencies, and also designed a resonant backshort structure that may further increase the optical efficiency. We are making progress towards integrating a spectrometer with a LEKID array and deploying a prototype device to a telescope for first light.Comment: 7 pages, 4 figures, submitted to Journal of Low Temperature Physic

Graphene-based fiber polarizer with PVB-enhanced light interaction

Graphene is a two-dimensional material which, as a result of its excellent photonic properties, has been investigated for a wide range of optical applications. In this paper, we propose and fabricate a commercial grade broadband graphene-based fiber polarizer using a low loss side-polished optical fiber platform. A high index polyvinyl butyral layer is used to enhance the light-graphene interaction of the evanescent field of the core guided mode to simultaneously obtain a high extinction ratio ~37.5 dB with a low device loss ~1 dB. Characterization of the optical properties reveals that the polarizer retains low transmission losses and high extinction ratios across an extended telecoms band. The results demonstrate that side-polished fibers are a useful platform for leveraging the unique properties of low-dimensional materials in a robust and compact device geometry