255 research outputs found

    Design for Sustainability at Seaside

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    Text by Gary Coates. Drawings by Atul Kukreja, Murali Ramaswami, Jay De Shelter, Doaa Passyalia, Diane Fox The most significant fact about our advanced industrial society is that it is not sustainable. Over the past one hundred years we have created a pattern of human settlements entirely dependent upon constantly increasing supplies of fossil fuels and mineral resources that are certain to be nearly exhausted during the lifetime of someone born today..

    Advances in lightweight nickel electrode technology

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    Studies are currently underway to further the development of lightweight nickel electrode technology. Work is focused primarily on the space nickel-hydrogen system and nickel-iron system but is also applicable to the nickel-cadmium and nickel-zinc systems. The goal is to reduce electrode weight while maintaining or improving performance, thereby increasing electrode energy density. Two basic electrode structures are being investigated. The first is the traditional nickel sponge produced from sintered nickel-carbonyl powder. The second is a new material for this application which consists of a non-woven mat of nickel fiber. Electrodes are being manufactured, tested, and evaluated at the electrode and cell level

    Planning and the Paradox of Conscious Purpose

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    Since the discovery of fire, and in the past 7,000-10,000 years with the development of agriculture and the establishment of fixed settlements, the evolution of human culture has been the reverse of that of organic systems

    Gas chromatographic-electron capture analysis of disinfection byproducts from the chlorination of swimming pools and lake water

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    Trihalomethanes are a class of compounds that are restricted by the Environmental Protection Agency for drinking water. Water sources that contain a high amount of water life increase the amount of trihalomethanes produced when the water is chlorinated. Following the methods utilized by the Metropolitan Water District of Southern California, lake water from the Overton Arm of Lake Mead was sampled, chlorinated, extracted, and analyzed by a gas chromatograph equipped with an electron capture detector; Analysis of the data showed that the Boulder Basin of Lake Mead produced the highest concentrations of trihalomethanes. The lake\u27s Overton Arm showed more bromoform production and areas from Lake Mohave resembled the Boulder Basin; An extraction method was modified to isolate another group of halogenated compounds, known as haloacetic acids. Results showed that the methylation performed well however, the diazomethane methylated many compounds that were not being studied which interfered with the compounds that were being studied; The final portion of this research dealt with the levels of trihalomethanes produced by the chlorination of swimming pools in the Las Vegas Valley. Results of these samples showed that the public swimming pools produced more trihalomethanes, specifically chloroform, than the private swimming pools

    Toward a Phenomenology of Place and Place-Making: Interpreting Landscape, Lifeworld and Aesthetics

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    Places and place-making are two significant notions in current environmental and architectural literature. Phenomenological research, which is concerned with the essential nature of human experience and consciousness, indicates that the notion of place crystallizes and focuses one essential aspect of human existence - the inescapable requirement to always be somewhere..

    LES of high speed jet flow from convergent-divergent rectangular S-bend ducts using synthetic inlet conditions

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    The effect of upstream duct curvature on the exhaust plume of a jet engine is further studied. Using synthetically created turbulence, improvements are made to the flow through out the S-bend validation case previously studied. The effect of a contracting 70° S-bend duct on the over-expanded exhaust plume emanating from a rectangular nozzle of aspect ratio 5.8:1 at a nozzle pressure ratio of 2.5 and Reynolds number of 7.61×105 is then studied. A modified version of the synthetic eddy method for creating artificial turbulence is initially validated. The validation of the Hydra CFD code is then expanded upon for an S-bend duct including both RANS and LES methodologies. For the combined S-bend and nozzle cases the total pressure gradients that were previously observed at the nozzle exit plane for k-ε RANS are also similarly observed using LES with synthetically created in flow turbulence thus confirming the existence of such features. The calculations were carried out using an unstructured, median-dual CFD solver with predominantly hexahedral elements containing approximately 175 million nodes

    CFD based study of unconventional aeroengine exhaust systems

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    The effect of upstream duct curvature on the exhaust plume of a jet engine is cur- rently undocumented. Here, three different upstream curvatures are simulated using CFD to investigate the effect of upstream duct curvature on the over-expanded exhaust plume emanating from a rectangular nozzle of aspect ratio 5.8:1 at a nozzle pressure ratio of 2.5 and Reynolds number of 7.61 × 105. Due to the lack of available experimental data for curved ducts connected to high speed jets, the initial work was to validate the methodol- ogy for separate S-bend and rectangular nozzle high speed jet cases. These showed that RANS methods were poor for predicting secondary flows in the S-bend and for predicting mixing and potential core length in the rectangular jet. However, LES did show signifi- cant improvements for the rectangular jet and correctly predicts the shear layer mixing. Calculations were carried out using an unstructured, median-dual CFD solver with pre- dominantly hexahedral elements containing approximately 65.5−67.5 million nodes. For the combined S-bend and nozzle cases it was seen that increasing upstream duct curvature re- duces the potential core length and increases losses in the upstream duct. Transverse total pressure gradients were also observed at the nozzle exit plane in both k-ǫ and WALE LES turbulence models, however to a significantly smaller degree in the latter. The upstream duct curvature was also seen to have an impact on the shock cell development, altering both number and location

    Advances in lightweight nickel electrode technology

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    Studies are currently underway to further the development of lightweight nickel electrode technology. Work is focused primarily on the space nickel-hydrogen system and nickel-iron system but is also applicable to the nickel-cadmium and nickel-zinc systems. The goal is to reduce electrode weight while maintaining or improving performance thereby increasing electrode energy density. Two basic electrode structures are being investigated. The first is the traditional nickel sponge produced from sintered nickel-carbonyl powder and the second is a new material for this application which consists of a non-woven mat of nickel fiber. Electrodes are being manufactured, tested and evaluated at the electrode and cell level

    Resonance Broadening Induced Nonlinear Saturation of Kinetic Alfven Turbulence in the Interplanetary Plasma

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    The saturation of ion cyclotron Alfven turbulence excited by beam particles is investigated using resonance broadening theory. The stochastic scattering which decorrelates particles, includes both random acceleration by electric fields and a turbulent magnetic mirroring effect. Turbulent mirroring is shown to yield non-Gaussian corrections to the orbits even if the random electric and magnetic fields are Gaussian. The predicted steady-state turbulence level exhibits a peaked anglular distribution, with a maximum near Theta ~ 60 degrees.Comment: 5 pages (including 2 figures

    Hybrid simulations of positively and negatively charged pickup ions and cyclotron wave generation at Europa

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    In the vicinity of Europa, Galileo observed bursty Alfvén-cyclotron wave power at thegyrofrequencies of a number of species including K+,O+2,Na+, and Cl+, indicating the localized pickupof these species. Additional evidence for the presence of chlorine was the occurrence of both left-hand(LH) and right-hand (RH) polarized transverse wave power near the Cl+gyrofrequency, thought to bedue to the pickup of both Cl+and the easily formed chlorine anion, Cl−. To test this hypothesis, we useone-dimensional hybrid (kinetic ion, massless fluid electron) simulations for both positive and negativepickup ions and self-consistently reproduce the growth of both LH and RH Alfvén-cyclotron waves inagreement with linear theory. We show how the simultaneous generation of LH and RH waves can result innongyrotropic ion distributions and increased wave amplitudes, and how even trace quantities of negativepickup ions are able to generate an observable RH signal. Through comparing simulated and observed waveamplitudes, we are able to place the first constraints on the densities of Chlorine pickup ions in localizedregions at Europa
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