386 research outputs found

    Shape invariant model approach for functional data analysis in uncertainty and sensitivity studies

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    Dynamic simulators model systems evolving over time. Often, it operates iteratively over fixed number of time-steps. The output of such simulator can be considered as time series or discrete functional outputs. Metamodeling is an e ective method to approximate demanding computer codes. Numerous metamodeling techniques are developed for simulators with a single output. Standard approach to model a dynamic simulator uses the same method also for multi-time series outputs: the metamodel is evaluated independently at every time step. This can be computationally demanding in case of large number of time steps. In some cases, simulator outputs for di erent combinations of input parameters have quite similar behaviour. In this paper, we propose an application of shape invariant model approach to model dynamic simulators. This model assumes a common pattern shape curve and curve-specific di erences in amplitude and timing are modelled with linear transformations. We provide an e cient algorithm of transformation parameters estimation and subsequent prediction algorithm. The method was tested with a CO2 storage reservoir case using an industrial commercial simulator and compared with a standard single step approach. The method provides satisfactory predictivity and it does not depend on the number of involved time steps

    Performance and Carcass Traits of Market Beef Cattle Supplemented Self-Fed Byproducts on Pasture: Final Report

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    Over a two year period (2007 and 2008), 162 head of beef steers were finished with self-fed byproducts on cool season grass pastures. Yearling steers were continuously grazed at the Neely-Kinyon Farm in southwest Iowa on cool season grasses that were predominantly fescue at a stocking density of 2.25 head/acre. Half of the cattle were implanted (with Synovex®-S) or half were not. Cattle received a diet of either soyhulls-dried distillers grain with solubles (DDGS) or ground corn-dried distillers grains with solubles that was offered through self-feeders. The rations were mixed at a 1:1 ratio with a mineral balancer added which included Rumensin®. Live cattle performance and carcass traits were not affected by diet. Implanted cattle outgained non-implanted over the entire finishing period (3.52 lbs/d vs. 3.17 lbs/d). This led to implanted cattle coming off test heavier (1324 lbs vs. 1277 lbs) and railing with heavier carcasses (826 lbs vs. 800 lbs). Ribeye areas were greater (13.1 in2 vs. 12.7 in2) for implanted cattle; which was probably due to the heavier carcass weights. Non-implanted cattle had superior quality grades (55% vs. 40%) of low choice or better. Fatty acid profiles from the first year were analyzed and showed that raw beef samples from cattle on the soyhulls diet had significantly higher C18:2 In conclusion, pasture rearing cattle, when given access to self-fed by-products, provides for excellent performance on both live performance and carcass traits. Some considerations should be made by the feeder in regards to time of year when marketing cattle and the cattle’s genetics. This system is an alternative to high-grain conventional beef finishing production in feedlots

    Exergy storage of compressed air in cavern and cavern volume estimation of the large-scale compressed air energy storage system

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    Accurate estimation of the energy storage capacity of a cavern with a defined storage volume and type is the very first step in planning and engineering a Compressed Air Energy Storage (CAES) plant. The challenges in obtaining a reliable estimation arise in the complexity associated with the thermodynamics of the internal air compression and expansion processes and the coupled heat transfer with surroundings. This study developed the methodology for estimating the exergy storage capacity with a known cavern volume, as well as the cavern volume required for a defined exergy storage capacity with different operation and heat transfer conditions. The work started by developing the mathematical models of the thermodynamic responses of air in a cavern subject to cavern operation in isochoric uncompensated or isobaric compensated modes, and heat transfer conditions including isothermal, convective heat transfer (CHT) and adiabatic wall conditions. The simulated transient air pressure and temperature were verified with the operational data of the Huntorf CAES plant. The study of the Huntorf CAES cavern confirmed the importance of the heat transfer influence on the energy conversion performance. The increase of mass storage due to the reduced temperature variation leads to an enhanced total exergy storage of the cavern. According to our simulations, within the operating range of the Huntorf plant, 34.77% more exergy after the charging and 37.98% more exergy after throttling can be stored in the cavern with isothermal wall condition than those in the cavern with adiabatic wall condition. Also, the nearly isothermal behaviour and high operating pressure in the compensated isobaric cavern resulted in the high effectiveness of exergy storage per unit cavern volume. The required cavern volume of the assumed isobaric cavern operation can be reduced to only 35% of the current cavern volume at the Huntorf plant. Finally, cavern volumes for an operational gas storage facility were used to demonstrate the methodology in estimating the exergy storage capacity, which provided an initial assessment of the storage capacity in the UK

    Measurement of optical response of a detuned resonant sideband extraction gravitational wave detector

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    We report on the optical response of a suspended-mass detuned resonant sideband extraction (RSE) interferometer with power recycling. The purpose of the detuned RSE configuration is to manipulate and optimize the optical response of the interferometer to differential displacements (induced by gravitational waves) as a function of frequency, independently of other parameters of the interferometer. The design of our interferometer results in an optical gain with two peaks: an RSE optical resonance at around 4 kHz and a radiation pressure induced optical spring at around 41 Hz. We have developed a reliable procedure for acquiring lock and establishing the desired optical configuration. In this configuration, we have measured the optical response to differential displacement and found good agreement with predictions at both resonances and all other relevant frequencies. These results build confidence in both the theory and practical implementation of the more complex optical configuration being planned for Advanced LIGO

    Finishing Beef Cattle on Grass with Self-Fed By-Products

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    There has been increasing interest by consumers in beef from cattle that are finished or fattened “on grass” rather than in a conventional feedlot. Also recently, Iowa has had a proliferation of plants that produce ethanol from corn. The byproduct of this process is distillers dried grains with solubles (DDGS). The objective of this study was to feed beef cattle to market weight by grazing cool-season grass supplemented with self-fed by-product pellets

    Measurement of Optical Response of a Detuned Resonant Sideband Extraction Interferometer

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    We report on the optical response of a suspended-mass detuned resonant sideband extraction (RSE) interferometer with power recycling. The purpose of the detuned RSE configuration is to manipulate and optimize the optical response of the interferometer to differential displacements (induced by gravitational waves) as a function of frequency, independently of other parameters of the interferometer. The design of our interferometer results in an optical gain with two peaks: an RSE optical resonance at around 4 kHz and a radiation pressure induced optical spring at around 41 Hz. We have developed a reliable procedure for acquiring lock and establishing the desired optical configuration. In this configuration, we have measured the optical response to differential displacement and found good agreement with predictions at both resonances and all other relevant frequencies. These results build confidence in both the theory and practical implementation of the more complex optical configuration being planned for Advanced LIGO.Comment: 6 pages, 4 figures, for submission to Phys Rev Letter
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