Science.gov

Sample records for parabolic trough technology

  1. Federal technology alert. Parabolic-trough solar water heating

    SciTech Connect

    1998-04-01

    Parabolic-trough solar water heating is a well-proven renewable energy technology with considerable potential for application at Federal facilities. For the US, parabolic-trough water-heating systems are most cost effective in the Southwest where direct solar radiation is high. Jails, hospitals, barracks, and other facilities that consistently use large volumes of hot water are particularly good candidates, as are facilities with central plants for district heating. As with any renewable energy or energy efficiency technology requiring significant initial capital investment, the primary condition that will make a parabolic-trough system economically viable is if it is replacing expensive conventional water heating. In combination with absorption cooling systems, parabolic-trough collectors can also be used for air-conditioning. Industrial Solar Technology (IST) of Golden, Colorado, is the sole current manufacturer of parabolic-trough solar water heating systems. IST has an Indefinite Delivery/Indefinite Quantity (IDIQ) contract with the Federal Energy Management Program (FEMP) of the US Department of Energy (DOE) to finance and install parabolic-trough solar water heating on an Energy Savings Performance Contract (ESPC) basis for any Federal facility that requests it and for which it proves viable. For an ESPC project, the facility does not pay for design, capital equipment, or installation. Instead, it pays only for guaranteed energy savings. Preparing and implementing delivery or task orders against the IDIQ is much simpler than the standard procurement process. This Federal Technology Alert (FTA) of the New Technology Demonstration Program is one of a series of guides to renewable energy and new energy-efficient technologies.

  2. Parabolic-Trough Technology Roadmap: A Pathway for Sustained Commercial Development and Deployment of Parabolic-Trough Technology

    SciTech Connect

    Price, H.; Kearney, D.

    1999-01-31

    Technology roadmapping is a needs-driven technology planning process to help identify, select, and develop technology alternatives to satisfy a set of market needs. The DOE's Office of Power Technologies' Concentrating Solar Power (CSP) Program recently sponsored a technology roadmapping workshop for parabolic trough technology. The workshop was attended by an impressive cross section of industry and research experts. The goals of the workshop were to evaluate the market potential for trough power projects, develop a better understanding of the current state of the technology, and to develop a conceptual plan for advancing the state of parabolic trough technology. This report documents and extends the roadmap that was conceptually developed during the workshop.

  3. Test results, Industrial Solar Technology parabolic trough solar collector

    SciTech Connect

    Dudley, V.E.; Evans, L.R.; Matthews, C.W.

    1995-11-01

    Sandia National Laboratories and Industrial Solar Technology are cost-sharing development of advanced parabolic trough technology. As part of this effort, several configurations of an IST solar collector were tested to determine the collector efficiency and thermal losses with black chrome and black nickel receiver selective coatings, combined with aluminized film and silver film reflectors, using standard Pyrex{reg_sign} and anti-reflective coated Pyrex{reg_sign} glass receiver envelopes. The development effort has been successful, producing an advanced collector with 77% optical efficiency, using silver-film reflectors, a black nickel receiver coating, and a solgel anti-reflective glass receiver envelope. For each receiver configuration, performance equations were empirically derived relating collector efficiency and thermal losses to the operating temperature. Finally, equations were derived showing collector performance as a function of input insolation value, incident angle, and operating temperature.

  4. Session: Parabolic Troughs (Presentation)

    SciTech Connect

    Kutscher, C.

    2008-04-01

    The project description is R and D activities at NREL and Sandia aimed at lowering the delivered energy cost of parabolic trough collector systems and FOA awards to support industry in trought development. The primary objectives are: (1) support development of near-term parabolic trought technology for central station power generation; (2) support development of next-generation trought fields; and (3) support expansion of US trough industry. The major FY08 activities were: (1) improving reflector optics; (2) reducing receiver heat loss (including improved receiver coating and mitigating hydrogen accumulation); (3) measuring collector optical efficiency; (4) optimizing plant performance and reducing cost; (5) reducing plant water consumption; and (6) directly supporting industry needs, including FOA support.

  5. Norwich Technologies' Advanced Low-Cost Receivers for Parabolic Troughs

    SciTech Connect

    Stettenheim, Joel; McBride, Troy O.; Brambles, Oliver J.; Cashin, Emil A.

    2013-12-31

    This report summarizes the successful results of our SunShot project, Advanced Low-Cost Receivers for Parabolic Troughs. With a limited budget of $252K and in only 12 months, we have (1) developed validated optical and thermal models and completed rigorous optimization analysis to identify key performance characteristics as part of developing first-generation laboratory prototype designs, (2) built optical and thermal laboratory prototypes and test systems with associated innovative testing protocols, and (3) performed extensive statistically relevant testing. We have produced fully functioning optical and thermal prototypes and accurate, validated models shown to capture important underlying physical mechanisms. The test results from the first-generation prototype establish performance exceeding the FOA requirement of thermal efficiency >90% for a CSP receiver while delivering an exit fluid temperature of > 650 °C and a cost < $150/kWth. Our vacuum-free SunTrap receiver design provides improvements over conventional vacuum-tube collectors, allowing dramatic reductions in thermal losses at high operating temperature.

  6. Parabolic Trough Organic Rankine Cycle Power Plant

    SciTech Connect

    Canada, S.; Cohen, G.; Cable, R.; Brosseau, D.; Price, H.

    2005-01-01

    Arizona Public Service (APS) is required to generate a portion of its electricity from solar resources in order to satisfy its obligation under the Arizona Environmental Portfolio Standard (EPS). In recent years, APS has installed and operates over 4.5 MWe of fixed, tracking, and concentrating photovoltaic systems to help meet the solar portion of this obligation and to develop an understanding of which solar technologies provide the best cost and performance to meet utility needs. During FY04, APS began construction of a 1-MWe parabolic trough concentrating solar power plant. This plant represents the first parabolic trough plant to begin construction since 1991. The plant will also be the first commercial deployment of the Solargenix parabolic trough collector technology developed under contract to the National Renewable Energy Laboratory (NREL). The plant will use an organic Rankine cycle (ORC) power plant, provided by Ormat. The ORC power plant is much simpler than a conventional steam Rankine cycle power plant and allows unattended operation of the facility.

  7. Development of Molten-Salt Heat Transfer Fluid Technology for Parabolic Trough Solar Power Plants - Public Final Technical Report

    SciTech Connect

    Grogan, Dylan C. P.

    2013-08-15

    Executive Summary This Final Report for the "Development of Molten-Salt Heat Transfer Fluid (HTF) Technology for Parabolic Trough Solar Power Plants” describes the overall project accomplishments, results and conclusions. Phase 1 analyzed the feasibility, cost and performance of a parabolic trough solar power plant with a molten salt heat transfer fluid (HTF); researched and/or developed feasible component options, detailed cost estimates and workable operating procedures; and developed hourly performance models. As a result, a molten salt plant with 6 hours of storage was shown to reduce Thermal Energy Storage (TES) cost by 43.2%, solar field cost by 14.8%, and levelized cost of energy (LCOE) by 9.8% - 14.5% relative to a similar state-of-the-art baseline plant. The LCOE savings range met the project’s Go/No Go criteria of 10% LCOE reduction. Another primary focus of Phase 1 and 2 was risk mitigation. The large risk areas associated with a molten salt parabolic trough plant were addressed in both Phases, such as; HTF freeze prevention and recovery, collector components and piping connections, and complex component interactions. Phase 2 analyzed in more detail the technical and economic feasibility of a 140 MWe,gross molten-salt CSP plant with 6 hours of TES. Phase 2 accomplishments included developing technical solutions to the above mentioned risk areas, such as freeze protection/recovery, corrosion effects of applicable molten salts, collector design improvements for molten salt, and developing plant operating strategies for maximized plant performance and freeze risk mitigation. Phase 2 accomplishments also included developing and thoroughly analyzing a molten salt, Parabolic Trough power plant performance model, in order to achieve the project cost and performance targets. The plant performance model and an extensive basic Engineering, Procurement, and Construction (EPC) quote were used to calculate a real levelized cost of energy (LCOE) of 11.50

  8. Parabolic Trough VSHOT Optical Characterization in 2005-2006 (Presentation)

    SciTech Connect

    Wendelin, T.

    2006-02-01

    This presentation regarding parabolic trough VSHOT optical characterization describes trough deployment and operation phases including: development, manufacture/installation, and maintenance/operation.

  9. Adjustment and validation of a simulation tool for CSP plants based on parabolic trough technology

    NASA Astrophysics Data System (ADS)

    García-Barberena, Javier; Ubani, Nora

    2016-05-01

    The present work presents the validation process carried out for a simulation tool especially designed for the energy yield assessment of concentrating solar plants based on parabolic through (PT) technology. The validation has been carried out by comparing the model estimations with real data collected from a commercial CSP plant. In order to adjust the model parameters used for the simulation, 12 different days were selected among one-year of operational data measured at the real plant. The 12 days were simulated and the estimations compared with the measured data, focusing on the most important variables from the simulation point of view: temperatures, pressures and mass flow of the solar field, gross power, parasitic power, and net power delivered by the plant. Based on these 12 days, the key parameters for simulating the model were properly fixed and the simulation of a whole year performed. The results obtained for a complete year simulation showed very good agreement for the gross and net electric total production. The estimations for these magnitudes show a 1.47% and 2.02% BIAS respectively. The results proved that the simulation software describes with great accuracy the real operation of the power plant and correctly reproduces its transient behavior.

  10. Status of APS 1-Mwe Parabolic Trough Project

    SciTech Connect

    Canada, S.; Brosseau, D.; Kolb, G.; Moore, L.; Cable, R.; Price, H.

    2005-11-01

    Arizona Public Service (APS) is currently installing new power facilities to generate a portion of its electricity from solar resources that will satisfy its obligation under the Arizona Environmental Portfolio Standard (EPS). During FY04, APS began construction on a 1-MWe parabolic trough concentrating solar power plant. This plant represents the first parabolic trough plant to begin construction since 1991. Site preparation and construction activities continued throughout much of FY05, and startup activities are planned for Fall 2005 (with completion early in FY06). The plant will be the first commercial deployment of the Solargenix parabolic trough collector technology developed under contract to the National Renewable Energy Laboratory. The plant will use an organic Rankine cycle (ORC) power plant, provided by Ormat. The ORC power plant is much simpler than the conventional steam Rankine cycle plant and allows unattended operation of the facility.

  11. Parabolic trough solar power for competitive U.S. markets

    SciTech Connect

    Price, H.W.; Kistner, R.

    1999-07-01

    Nine parabolic trough power plants located in the California Mojave Desert represent the only commercial development of large-scale solar power plants to date. Although all nine plants continue to operate today, no new solar power plants have been completed since 190. Over the last several years, the parabolic trough industry has focused much of its efforts on international market opportunities. Although the power market in developing countries appears to offer a number of opportunities for parabolic trough technologies due to high growth and the availability of special financial incentives for renewables, these markets are also plagued with many difficulties for developers. In recent years, there has been some renewed interest in the U.S. domestic power market as a results of an emerging green market and green pricing incentives. Unfortunately, many of these market opportunities and incentives focus on smaller, more modular technologies (such as photovoltaics or wind power), and as a result they tend to exclude or are of minimum long-term benefit to large-scale concentrating solar power technologies. This paper looks at what is necessary for large-scale parabolic trough solar power plants to compete with state-of-the-art fossil power technology in a competitive US power market.

  12. Parabolic Trough Solar Power for Competitive U.S. Markets

    SciTech Connect

    Henry W. Price

    1998-11-01

    Nine parabolic trough power plants located in the California Mojave Desert represent the only commercial development of large-scale solar power plants to date. Although all nine plants continue to operate today, no new solar power plants have been completed since 1990. Over the last several years, the parabolic trough industry has focused much of its efforts on international market opportunities. Although the power market in developing countries appears to offer a number of opportunities for parabolic trough technologies due to high growth and the availability of special financial incentives for renewables, these markets are also plagued with many difficulties for developers. In recent years, there has been some renewed interest in the U.S. domestic power market as a result of an emerging green market and green pricing incentives. Unfortunately, many of these market opportunities and incentives focus on smaller, more modular technologies (such as photovoltaics or wind power), and as a result they tend to exclude or are of minimum long-term benefit to large-scale concentrating solar power technologies. This paper looks at what is necessary for large-scale parabolic trough solar power plants to compete with state-of-the-art fossil power technology in a competitive U.S. power market.

  13. Solar Thermal Power Plants with Parabolic-Trough Collectors

    NASA Astrophysics Data System (ADS)

    Zarza, E.; Valenzuela, L.; León, J.

    2004-12-01

    Parabolic-trough collectors (PTC) are solar concentrating devices suitable to work in the 150°C- 400°C temperature range. Power plants based on this type of solar collectors are a very efficient way to produce electricity with solar energy. At present, there are eight commercial solar plants (called SEGS-II, III,.. IX) producing electricity with parabolic-trough collectors and their total output power is 340 MW. Though all SEGS plants currently in operation use thermal oil as a heat transfer fluid between the solar field and the power block, direct steam generation (DSG) in the receiver tubes is a promising option to reduce the cost of electricity produced with parabolic- trough power plants. Most of technical uncertainties associated to the DSG technology were studied and solved in the DISS project and it is expected that this new technology will be commercially available in a short term. In Spain, the Royal Decree No. 436/204 (March 12th , 2004) has defined a premium of 0,18€/kWh for the electricity produced by solar thermal power plants, thus promoting the installation of solar thermal power plants up to a limit of 200 MW. Due to the current legal and financial framework defined in Spain, several projects to install commercial solar power plants with parabolic-trough collectors are currently underway.

  14. Alignment method for parabolic trough solar concentrators

    DOEpatents

    Diver, Richard B.

    2010-02-23

    A Theoretical Overlay Photographic (TOP) alignment method uses the overlay of a theoretical projected image of a perfectly aligned concentrator on a photographic image of the concentrator to align the mirror facets of a parabolic trough solar concentrator. The alignment method is practical and straightforward, and inherently aligns the mirror facets to the receiver. When integrated with clinometer measurements for which gravity and mechanical drag effects have been accounted for and which are made in a manner and location consistent with the alignment method, all of the mirrors on a common drive can be aligned and optimized for any concentrator orientation.

  15. Gas Turbine/Solar Parabolic Trough Hybrid Designs: Preprint

    SciTech Connect

    Turchi, C. S.; Ma, Z.; Erbes, M.

    2011-03-01

    A strength of parabolic trough concentrating solar power (CSP) plants is the ability to provide reliable power by incorporating either thermal energy storage or backup heat from fossil fuels. Yet these benefits have not been fully realized because thermal energy storage remains expensive at trough operating temperatures and gas usage in CSP plants is less efficient than in dedicated combined cycle plants. For example, while a modern combined cycle plant can achieve an overall efficiency in excess of 55%; auxiliary heaters in a parabolic trough plant convert gas to electricity at below 40%. Thus, one can argue the more effective use of natural gas is in a combined cycle plant, not as backup to a CSP plant. Integrated solar combined cycle (ISCC) systems avoid this pitfall by injecting solar steam into the fossil power cycle; however, these designs are limited to about 10% total solar enhancement. Without reliable, cost-effective energy storage or backup power, renewable sources will struggle to achieve a high penetration in the electric grid. This paper describes a novel gas turbine / parabolic trough hybrid design that combines solar contribution of 57% and higher with gas heat rates that rival that for combined cycle natural gas plants. The design integrates proven solar and fossil technologies, thereby offering high reliability and low financial risk while promoting deployment of solar thermal power.

  16. Performance contracting for parabolic trough solar thermal systems

    SciTech Connect

    Brown, H.; Hewett, R.; Walker, A.; Gee, R.; May, K.

    1997-12-31

    Several applications of solar energy have proven viable in the energy marketplace, due to competitive technology and economic performance. One example is the parabolic trough solar collectors, which use focused solar energy to maximize efficiency and reduce material use in construction. Technical improvements are complemented by new business practices to make parabolic trough solar thermal systems technically and economically viable in an ever widening range of applications. Technical developments in materials and fabrication techniques reduce production cost and expand applications from swimming pool heating and service hot water, to higher-temperature applications such as absorption cooling and process steam. Simultaneously, new financing mechanisms such as a recently awarded US Department of Energy (DOE) Federal Energy Management Program (FEMP) indefinite quantity Energy Savings Performance Contract (Super ESPC) facilitate and streamline implementation of the technology in federal facilities such as prisons and military bases.

  17. Development of sheet-metal parabolic-trough reflector panels

    SciTech Connect

    Biester, A.W.

    1982-06-01

    Efforts to develop accurate, durable, and mass producible sheet metal parabolic trough solar collectors and the associated support for the collectors are described. The design considered is similar to an automobile hood, a two-piece sheet metal structure consisting of a formed steel frame or stiffening panel and a smooth contoured skin. The two pieces may be bonded or welded to form a rigid structure, and a reflective surface applied such as a film, glass mirror, or any of the presently utilized materials. The work encompassed material selection, adhesive selection and testing, tool design and fabrication, prototype panel production, and design and development of torque tube assemblies on which the trough is inclined. Appended are results of adhesive bonding studies. It is found that high volume technology can be used to produce accurate and structurally sound reflector panels, and one configuration has been selected for fabrication in suitable quantities for performance testing. (LEW)

  18. Optimal Heat Collection Element Shapes for Parabolic Trough Concentrators

    SciTech Connect

    Bennett, C

    2007-11-15

    For nearly 150 years, the cross section of the heat collection tubes used at the focus of parabolic trough solar concentrators has been circular. This type of tube is obviously simple and easily fabricated, but it is not optimal. It is shown in this article that the optimal shape, assuming a perfect parabolic figure for the concentrating mirror, is instead oblong, and is approximately given by a pair of facing parabolic segments.

  19. Absorber Alignment Measurement Tool for Solar Parabolic Trough Collectors: Preprint

    SciTech Connect

    Stynes, J. K.; Ihas, B.

    2012-04-01

    As we pursue efforts to lower the capital and installation costs of parabolic trough solar collectors, it is essential to maintain high optical performance. While there are many optical tools available to measure the reflector slope errors of parabolic trough solar collectors, there are few tools to measure the absorber alignment. A new method is presented here to measure the absorber alignment in two dimensions to within 0.5 cm. The absorber alignment is measured using a digital camera and four photogrammetric targets. Physical contact with the receiver absorber or glass is not necessary. The alignment of the absorber is measured along its full length so that sagging of the absorber can be quantified with this technique. The resulting absorber alignment measurement provides critical information required to accurately determine the intercept factor of a collector.

  20. A roadmap for parabolic trough progress in large-scale power generation

    SciTech Connect

    Kearney, D.W.; Price, H.W.

    1999-07-01

    In 1998 the US DOE/Sun{sm_bullet}Lab sponsored a workshop to discuss and outline a pathway for sustained deployment of commercial parabolic trough power technology. Including both industry and institutional interests, a plan emerged to move to the next step in trough installations. Backed by over ten years operating experience of 354 MW of trough steam plants in the California Mojave Desert, the plan explored future markets, technology advancements, and improvements in cost-effectiveness. This paper highlights the key conclusions and findings that were subsequently documented in the DOE parabolic trough technology roadmap report. Initially, the cost of trough solar power is expected to be 10--12{cents} kWh, depending on plant configuration. After initial market subsidies by GEF buy-down grants or other special green/renewable financing options, and with the next level of technology development, the cost of trough power should reduce to 6--8{cents} kWh. With further reduction of electricity costs below 6{cents} kWh, projections suggest that achievement of up to 1 gigawatt (GW) installed capacity by 2005 and 5 GW by 2010 are possible.

  1. Reducing the Cost of Energy from Parabolic Trough Solar Power Plants: Preprint

    SciTech Connect

    Price, H.; Kearney, D.

    2003-01-01

    Parabolic trough solar technology is the most proven and lowest cost large-scale solar power technology available today, primarily because of the nine large commercial-scale solar power plants that are operating in the California Mojave Desert. However, no new plants have been built during the past ten years because the cost of power from these plants is more expensive than power from conventional fossil fuel power plants. This paper reviews the current cost of energy and the potential for reducing the cost of energy from parabolic trough solar power plant technology based on the latest technological advancements and projected improvements from industry and sponsored R&D. The paper also looks at the impact of project financing and incentives on the cost of energy.

  2. Development effort of sheet molding compound (SMC) parabolic trough panels

    SciTech Connect

    Kirsch, P.A.; Champion, R.L.

    1982-01-01

    The objectives of the development effort are to: investigate the problems of molding parabolic trough solar reflector panels of sheet molding compound (SMC); develop molding techniques and processes by which silvered glass reflector sheets can be integrally molded into SMC trough panels; provide representative prototype panels for evaluation; and provide information regarding the technical feasibility of molding SMC panels in high volume production. The approach taken to meet the objectives was to design the parabolic panel, fabricate a prototype die, choose an SMC formulation and mold the glass and SMC together into a vertex to rim mirrored panel. The main thrust of the program was to successfully co-mold a mirrored glass sheet with the SMC. Results indicate that mirrored glass sheets, if properly strengthened to withstand the temperature and pressure of the molding process, can be successfully molded with SMC in a single press stroke using standard compression molding techniques. The finalized design of the trough panel is given. The SMC formulation chosen is a low shrink, low profile SMC using 40% by weight one inch chopped glass fibers in a uv stabilized polyester resin matrix. A program to test for the adhesion between mirrored glass sheets and the SMC is discussed briefly. (LEW)

  3. Parabolic Trough Collector Cost Update for the System Advisor Model (SAM)

    SciTech Connect

    Kurup, Parthiv; Turchi, Craig S.

    2015-11-01

    This report updates the baseline cost for parabolic trough solar fields in the United States within NREL's System Advisor Model (SAM). SAM, available at no cost at https://sam.nrel.gov/, is a performance and financial model designed to facilitate decision making for people involved in the renewable energy industry. SAM is the primary tool used by NREL and the U.S. Department of Energy (DOE) for estimating the performance and cost of concentrating solar power (CSP) technologies and projects. The study performed a bottom-up build and cost estimate for two state-of-the-art parabolic trough designs -- the SkyTrough and the Ultimate Trough. The SkyTrough analysis estimated the potential installed cost for a solar field of 1500 SCAs as $170/m2 +/- $6/m2. The investigation found that SkyTrough installed costs were sensitive to factors such as raw aluminum alloy cost and production volume. For example, in the case of the SkyTrough, the installed cost would rise to nearly $210/m2 if the aluminum alloy cost was $1.70/lb instead of $1.03/lb. Accordingly, one must be aware of fluctuations in the relevant commodities markets to track system cost over time. The estimated installed cost for the Ultimate Trough was only slightly higher at $178/m2, which includes an assembly facility of $11.6 million amortized over the required production volume. Considering the size and overall cost of a 700 SCA Ultimate Trough solar field, two parallel production lines in a fully covered assembly facility, each with the specific torque box, module and mirror jigs, would be justified for a full CSP plant.

  4. LCOE reduction for parabolic trough CSP: Innovative solar receiver with improved performance at medium temperature

    NASA Astrophysics Data System (ADS)

    Stollo, A.; Chiarappa, T.; D'Angelo, A.; Maccari, A.; Matino, F.

    2016-05-01

    Concentrated Solar Power (CSP) applications represent an effective possibility to gain energy from the Sun; however, the lasting CSP market crisis compels continuous improvements in terms of cost reduction and performance increase. Focused on parabolic trough technology, this paper describes the innovation studied and realized on solar receivers to gain optimized optical performance while increasing the production versatility, hence boosting the solar plant efficiency and finally reducing the estimated LCOE.

  5. Exergetic analysis of parabolic trough solar thermal power plants

    NASA Astrophysics Data System (ADS)

    Petrakopoulou, F.; Ruperez, B.; San Miguel, G.

    2014-12-01

    A very important component to achieve sustainable development in the energy sector is the improvement of energy efficiency of widely applied thermodynamic processes. Evaluation and optimization methods of energy processes play a crucial role in fulfilling this goal. A suitable method for the evaluation and optimization of energy conversion systems has been proven to be the exergetic analysis. In this work, two parabolic trough solar thermal power plants are simulated in detail using commercial software, and they are further analysed and compared using an exergetic analysis. The first plant uses a thermal fluid to produce the steam required in a steam generator, while the second one produces the steam directly in the solar field. The analysis involves the evaluation of the individual components of the power plants, as well as the performance evaluation of the overall structures. The main goal is to detect thermodynamic inefficiencies of the two different configurations and propose measures to minimize those. We find that the two examined plants have similar main sources of exergy destruction: the solar field (parabolic trough solar collectors), followed by the steam generator. This reveals the importance of an optimal design of these particular components, which could reduce inefficiencies present in the system. The differences in the exergy destruction and exergetic efficiencies of individual components of the two plants are analyzed in detail based on comparable operational conditions.

  6. Simulation of point light concentration with parabolic trough collector

    NASA Astrophysics Data System (ADS)

    Danylyuk, Andriy; Zettl, Marcus; Lynass, Mark

    2010-08-01

    As the amount of solar generated energy usage increases worldwide, researches are turning to more advanced methods to increase collection efficiencies and drive down system costs. In this paper, four different optical system designs for solar concentrator applications are discussed. Each of the designs studied utilizes a parabolic trough optical element. The use of the parabolic trough in conjunction with a secondary optical component eliminates the need for expensive complicated 2-axis tracking, whilst still allowing the precise point focus normally only possible with more complex paraboloid systems. The result is an optical system, which offers all the advantages of a linear focus geometry combined with the possibility to utilize point focus concentration. The results were obtained using photometric geometrical ray tracing methods. Ideal surface simulations were initially used to separate surface from geometrical loss contributions. Later, more realistic simulations, including surface and reflectivity data of typical manufacturing methods and materials, were used to compare optical output power densities and system losses. For the systems studied, the minimum and maximum optical efficiencies obtained were 76.73% and 81% respectively. The AM 1.5 solar spectrum power densities in the absorption plane ranged from 50 to 195.8Wm-2.

  7. Mechanism of Hydrogen Formation in Solar Parabolic Trough Receivers

    SciTech Connect

    Moens, L.; Blake, D. M.

    2008-03-01

    Solar parabolic trough systems for electricity production are receiving renewed attention, and new solar plants are under construction to help meet the growing demands of the power market in the Western United States. The growing solar trough industry will rely on operating experience it has gained over the last two decades. Recently, researchers found that trough plants that use organic heat transfer fluids (HTF) such as Therminol VP-1 are experiencing significant heat losses in the receiver tubes. The cause has been traced back to the accumulation of excess hydrogen gas in the vacuum annulus that surrounds the steel receiver tube, thus compromising the thermal insulation of the receiver. The hydrogen gas is formed during the thermal decomposition of the organic HTF that circulates inside the receiver loop, and the installation of hydrogen getters inside the annulus has proven to be insufficient for controlling the hydrogen build-up over the lifetime of the receivers. This paper will provide an overview of the chemical literature dealing with the thermal decomposition of diphenyl oxide and biphenyl, the two constituents of Therminol VP-1.

  8. Current and Future Costs for Parabolic Trough and Power Tower Systems in the US Market: Preprint

    SciTech Connect

    Turchi, C.; Mehos, M.; Ho, C. K.; Kolb, G. J.

    2010-10-01

    NREL's Solar Advisor Model (SAM) is employed to estimate the current and future costs for parabolic trough and molten salt power towers in the US market. Future troughs are assumed to achieve higher field temperatures via the successful deployment of low melting-point, molten-salt heat transfer fluids by 2015-2020. Similarly, it is assumed that molten salt power towers are successfully deployed at 100MW scale over the same time period, increasing to 200MW by 2025. The levelized cost of electricity for both technologies is predicted to drop below 11 cents/kWh (assuming a 10% investment tax credit and other financial inputs outlined in the paper), making the technologies competitive in the marketplace as benchmarked by the California MPR. Both technologies can be deployed with large amounts of thermal energy storage, yielding capacity factors as high as 65% while maintaining an optimum LCOE.

  9. Modeling of a Parabolic Trough Solar Field for Acceptance Testing: A Case Study

    SciTech Connect

    Wagner, M. J.; Mehos, M. S.; Kearney, D. W.; McMahan, A. C.

    2011-01-01

    As deployment of parabolic trough concentrating solar power (CSP) systems ramps up, the need for reliable and robust performance acceptance test guidelines for the solar field is also amplified. Project owners and/or EPC contractors often require extensive solar field performance testing as part of the plant commissioning process in order to ensure that actual solar field performance satisfies both technical specifications and performance guaranties between the involved parties. Performance test code work is currently underway at the National Renewable Energy Laboratory (NREL) in collaboration with the SolarPACES Task-I activity, and within the ASME PTC-52 committee. One important aspect of acceptance testing is the selection of a robust technology performance model. NREL1 has developed a detailed parabolic trough performance model within the SAM software tool. This model is capable of predicting solar field, sub-system, and component performance. It has further been modified for this work to support calculation at subhourly time steps. This paper presents the methodology and results of a case study comparing actual performance data for a parabolic trough solar field to the predicted results using the modified SAM trough model. Due to data limitations, the methodology is applied to a single collector loop, though it applies to larger subfields and entire solar fields. Special consideration is provided for the model formulation, improvements to the model formulation based on comparison with the collected data, and uncertainty associated with the measured data. Additionally, this paper identifies modeling considerations that are of particular importance in the solar field acceptance testing process and uses the model to provide preliminary recommendations regarding acceptable steady-state testing conditions at the single-loop level.

  10. CSP parabolic trough and power tower performance analysis through the Southern African universities radiometric network (SAURAN) data

    NASA Astrophysics Data System (ADS)

    Pidaparthi, A. S.; Dall, E. P.; Hoffmann, J. E.; Dinter, F.

    2016-05-01

    The objective of this paper is to analyse the performance of parabolic trough and power tower technologies by selecting two radiometric stations in different geographic locations, with approximately equal annual direct normal irradiance (DNI) values, but with different monthly DNI distributions. The two stations chosen for this study are situated at the University of Free State, Bloemfontein, Free State Province and in Vanrhynsdorp, Western Cape Province. The annual measured DNI values for both these locations in South Africa are in the range of 2500-2700 kWh/m2. The comparison between the different monthly DNI distributions of these selected sites includes an assessment of annual hourly data in order to study the performance analysis of the most mature concentrating solar power (CSP) technologies, namely parabolic trough and power tower plants. The weather data has been obtained from the Southern African Universities Radiometric Network (SAURAN). A comparison between the different monthly DNI distributions of these selected sites includes the assessment of hourly data. Selection of these radiometric stations has also been done on the basis that they have been operational for at least one year. The first year that most SAURAN stations have been online for at least one year is 2014, thus data from this year has been considered. The annual performance analysis shows that parabolic trough plants have a higher energy yield in Vanrhynsdorp while power tower plants seem to be more suitable for Bloemfontein. Power tower plants in both the locations have a higher annual energy yield when compared with parabolic trough plants. A parabolic trough power plant in Vanrhynsdorp in the Western Cape Province has very low monthly electricity generation in the winter months of May, June, July and August. This is partly due to the higher cosine losses in the parabolic trough `one-axis' tracking systems and lower DNI values in the winter months. However, a power tower plant in

  11. Coupling flexible solar cell with parabolic trough solar-concentrator-prototype design and performance

    NASA Astrophysics Data System (ADS)

    Panin, Alexander; Bergquist, Jonathon

    2007-10-01

    Solar cells are still too expensive (5-20/watt) to compete with traditional fossil fuel power generating methods (˜1/watt). Parabolic trough solar concentrator has the advantage of modest concentration ratio (10-100) which is well suited for coupling with solar cell. Thus using small area solar cell placed in the focal line of parabolic trough may be economically viable alternative to flat solar panels. We experiment with flexible solar cell (backed by water cooling pipe) placed in the focus of parabolic trough reflector. Another advantage of parabolic trough concentrator is very relaxed tracking requirement. For example, east-west oriented concentrator (aligned with the ecliptic plane) does not even need any tracking during core 4-6 hours around noon (when maximum illumination is available). The design and the performance of the prototype, as well as possible economical benefits of full scale projects are discussed in the presentation.

  12. Wind Tunnel Tests of Parabolic Trough Solar Collectors: March 2001--August 2003

    SciTech Connect

    Hosoya, N.; Peterka, J. A.; Gee, R. C.; Kearney, D.

    2008-05-01

    Conducted extensive wind-tunnel tests on parabolic trough solar collectors to determine practical wind loads applicable to structural design for stress and deformation, and local component design for concentrator reflectors.

  13. Numerical simulation of a parabolic trough solar collector for hot water and steam generation

    NASA Astrophysics Data System (ADS)

    Hachicha, Ahmed Amine

    2016-05-01

    Parabolic trough solar collectors (PTCs) are currently one of the most mature and prominent solar technology for the production of electricity. In order to reduce the electricity cost and improve the overall efficiency, Direct Steam generation (DSG) technology can be used for industrial heat process as well as in the solar fields for electricity production. In the last decades, this technology is experiencing an important development last decades and it is considered as one of the most feasible process for the next generation of power plants using PTCs. A numerical model based on Finite Volume Method (FVM) balance is presented to predict the thermal behavior of a parabolic trough solar collector used for hot water and steam generation. The realistic non-uniform solar flux is calculated in a pre-processing task and inserted to the general model. A numerical-geometrical method based on ray trace and FVM techniques is used to determine the solar flux distribution around the absorber tube with high accuracy.

  14. Parabolic trough collector power plant performance simulation for an interactive solar energy Atlas of Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Ibarra, Mercedes; Frasquet, Miguel; Al Rished, Abdulaziz; Tuomiranta, Arttu; Gasim, Sami; Ghedira, Hosni

    2016-05-01

    The collaboration between the Research Center for Renewable Energy Mapping and Assessment (ReCREMA) at Masdar Institute of Science and Technology and the King Abdullah City for Atomic & Renewable Energy (KACARE) aims to create an interactive web tool integrated in the Renewable Resource Atlas where different solar thermal electricity (STE) utility-scale technologies will be simulated. In this paper, a methodology is presented for sizing and performance simulation of the solar field of parabolic trough collector (PTC) plants. The model is used for a case study analysis of the potential of STE in three sites located in the central, western, and eastern parts of Saudi Arabia. The plant located in the north (Tayma) has the lowest number of collectors with the best production along the year.

  15. The 3D heat flux density distribution on a novel parabolic trough wavy absorber

    NASA Astrophysics Data System (ADS)

    Demagh, Yassine; Kabar, Yassine; Bordja, Lyes; Noui, Samira

    2016-05-01

    The non-uniform concentrated solar flux distribution on the outer surface of the absorber pipe can lead to large circumferential gradient temperature and high concentrated temperature of the absorber pipe wall, which is one of the primary causes of parabolic trough solar receiver breakdown. In this study, a novel shape of the parabolic trough absorber pipe is proposed as a solution to well homogenize the solar flux distribution, as well as, the temperature in the absorber wall. The conventional straight absorber located along the focal line of the parabola is replaced by wavy one (invention patent by Y. Demagh [1]) for which the heat flux density distribution on the outer surface varies in both axial and azimuthal directions (3D) while it varies only in the azimuthal direction on the former (2D). As far as we know, there is not previous study which has used a longitudinally wavy pipe as an absorber into the parabolic trough collector unit.

  16. Gas Turbine/Solar Parabolic Trough Hybrid Design Using Molten Salt Heat Transfer Fluid: Preprint

    SciTech Connect

    Turchi, C. S.; Ma, Z.

    2011-08-01

    Parabolic trough power plants can provide reliable power by incorporating either thermal energy storage (TES) or backup heat from fossil fuels. This paper describes a gas turbine / parabolic trough hybrid design that combines a solar contribution greater than 50% with gas heat rates that rival those of natural gas combined-cycle plants. Previous work illustrated benefits of integrating gas turbines with conventional oil heat-transfer-fluid (HTF) troughs running at 390?C. This work extends that analysis to examine the integration of gas turbines with salt-HTF troughs running at 450 degrees C and including TES. Using gas turbine waste heat to supplement the TES system provides greater operating flexibility while enhancing the efficiency of gas utilization. The analysis indicates that the hybrid plant design produces solar-derived electricity and gas-derived electricity at lower cost than either system operating alone.

  17. Analytical Approach Treating Three-Dimensional Geometrical Effects of Parabolic Trough Collectors: Preprint

    SciTech Connect

    Binotti, M.; Zhu, G.; Gray, A.; Manzollini, G.

    2012-04-01

    An analytical approach, as an extension of one newly developed method -- First-principle OPTical Intercept Calculation (FirstOPTIC) -- is proposed to treat the geometrical impact of three-dimensional (3-D) effects on parabolic trough optical performance. The mathematical steps of this analytical approach are presented and implemented numerically as part of the suite of FirstOPTIC code. In addition, the new code has been carefully validated against ray-tracing simulation results and available numerical solutions. This new analytical approach to treating 3-D effects will facilitate further understanding and analysis of the optical performance of trough collectors as a function of incidence angle.

  18. Parabolic dishes: technology and economics

    SciTech Connect

    Shine, D.J.

    1983-06-01

    The status of parabolic dish technology is described in this paper. The system consists of a dish-shaped concentrator that focuses the sun's rays on a heat transfer fluid. Receivers must be developed to withstand high temperatures. The Brayton engine is recommended by Saunders Associates because it is low cost, has the highest conversion efficiency, uses ordinary atmospheric air, and comes in appropriate sizes. Storage systems can augment periods of solar operation as specified. A true commercial market will not emerge until systems level testing over an extended period has taken place. Federal support of advanced system development is needed.

  19. Slope Error Measurement Tool for Solar Parabolic Trough Collectors: Preprint

    SciTech Connect

    Stynes, J. K.; Ihas, B.

    2012-04-01

    The National Renewable Energy Laboratory (NREL) has developed an optical measurement tool for parabolic solar collectors that measures the combined errors due to absorber misalignment and reflector slope error. The combined absorber alignment and reflector slope errors are measured using a digital camera to photograph the reflected image of the absorber in the collector. Previous work using the image of the reflection of the absorber finds the reflector slope errors from the reflection of the absorber and an independent measurement of the absorber location. The accuracy of the reflector slope error measurement is thus dependent on the accuracy of the absorber location measurement. By measuring the combined reflector-absorber errors, the uncertainty in the absorber location measurement is eliminated. The related performance merit, the intercept factor, depends on the combined effects of the absorber alignment and reflector slope errors. Measuring the combined effect provides a simpler measurement and a more accurate input to the intercept factor estimate. The minimal equipment and setup required for this measurement technique make it ideal for field measurements.

  20. Towards standardization of in-site parabolic trough collector testing in solar thermal power plants

    NASA Astrophysics Data System (ADS)

    Sallaberry, Fabienne; Valenzuela, Loreto; de Jalón, Alberto García; Leon, Javier; Bernad, Ignacio David

    2016-05-01

    This paper presents a summary of the testing procedure and a validation of the methodology of parabolic trough collector in solar thermal power plants. The applied testing methodology is the one proposed within the Spanish standardization sub-committee AEN/CTN 206/SC117 working group WG2 related to the components for solar thermal power plants. This methodology is also proposed within the international committee IEC TC 117 (Standard draft IEC 62862-3-2 Ed. 1.0). This study is done at Plataforma Solar de Almería (PSA) in Almeria within the European project STAGE-STE. This paper presents the results of the optical and thermal efficiency of a large-size parabolic trough collector. The obtained values are similar to the previous analysis on this collector by PSA. The results of the tracking system have a good accuracy compared to the acceptance angle of the concentrator.

  1. Near-term improvements in parabolic troughs: an economic and performance assessment

    SciTech Connect

    Gee, R.; Murphy, L.M.

    1981-08-01

    Improved parabolic-trough concentrating collectors will result from better design, improved fabrication techniques, and the development and utilization of improved materials. This analysis qualifies the performance potential of various parabolic-trough component improvements from a systems viewpoint and uses these performance data to determine the worth of each improvement on an economic basis. The improvements considered are evacuated receivers, silvered-glass reflectors, improved receiver, selective coatings, higher optical accuracy concentrations, and higher transmittance receiver glazings. Upper-bound costs for each improvement are provided as well as estimates of the increased solar system rates of return that are made possible by these improvements. The performance and economic potential of some of these improvements are shown to be substantial, especially at higher collector operating temperatures.

  2. Low-cost small scale parabolic trough collector design for manufacturing and deployment in Africa

    NASA Astrophysics Data System (ADS)

    Orosz, Matthew; Mathaha, Paul; Tsiu, Anadola; Taele, B. M.; Mabea, Lengeta; Ntee, Marcel; Khakanyo, Makoanyane; Teker, Tamer; Stephens, Jordan; Mueller, Amy

    2016-05-01

    Concentrating Solar Power is expanding its deployment on the African subcontinent, highlighting the importance of efforts to indigenize manufacturing of this technology to increase local content and therefore local economic benefits of these projects. In this study a design for manufacturing (DFM) exercise was conducted to create a locally produced parabolic trough collector (the G4 PTC). All parts were sourced or fabricated at a production facility in Lesotho, and several examples of the design were prototyped and tested with collaborators in the Government of Lesotho's Appropriate Technology Services division and the National University of Lesotho. Optical and thermal performance was simulated and experimentally validated, and pedagogical pre-commercial versions of the PTC have been distributed to higher education partners in Lesotho and Europe. The cost to produce the PTC is 180 USD/m2 for a locally manufactured heat collection element (HCE) capable of sustaining 250C operation at ~65% efficiency. A version with an imported evacuated HCE can operate at 300°C with 70% efficiency. Economically relevant applications for this locally produced PTC include industrial process heat and distributed generation scenarios where cogeneration is required.

  3. Archimede solar energy molten salt parabolic trough demo plant: Improvements and second year of operation

    NASA Astrophysics Data System (ADS)

    Maccari, Augusto; Donnola, Sandro; Matino, Francesca; Tamano, Shiro

    2016-05-01

    Since July 2013, the first stand-alone Molten Salt Parabolic Trough (MSPT) demo plant, which was built in collaboration with Archimede Solar Energy and Chiyoda Corporation, is in operation, located adjacent to the Archimede Solar Energy (ASE) manufacturing plant in Massa Martana (Italy). During the two year's operating time frame, the management of the demo plant has shown that MSPT technology is a suitable and reliable option. Several O&M procedures and tests have been performed, as Heat Loss and Minimum Flow Test, with remarkable results confirming that this technology is ready to be extended to standard size CSP plant, if the plant design takes into account molten salt peculiarities. Additionally, the plant has been equipped on fall 2014 with a Steam Generator system by Chiyoda Corporation, in order to test even this important MSPT plant subsystem and to extend the solar field active time, overcoming the previous lack of an adequate thermal load. Here, a description of the plant improvements and the overall plant operation figures will be presented.

  4. Development of Performance Acceptance Test Guidelines for Large Commercial Parabolic Trough Solar Fields: Preprint

    SciTech Connect

    Kearney, D.; Mehos, M.

    2010-12-01

    Prior to commercial operation, large solar systems in utility-size power plants need to pass a performance acceptance test conducted by the EPC contractor or owners. In lieu of the present absence of engineering code developed for this purpose, NREL has undertaken the development of interim guidelines to provide recommendations for test procedures that can yield results of a high level of accuracy consistent with good engineering knowledge and practice. The fundamental differences between acceptance of a solar power plant and a conventional fossil-fired plant are the transient nature of the energy source and the necessity to utilize an analytical performance model in the acceptance process. These factors bring into play the need to establish methods to measure steady state performance, potential impacts of transient processes, comparison to performance model results, and the possible requirement to test, or model, multi-day performance within the scope of the acceptance test procedure. The power block and BOP are not within the boundaries of this guideline. The current guideline is restricted to the solar thermal performance of parabolic trough systems and has been critiqued by a broad range of stakeholders in CSP development and technology.

  5. Structural design for high-power parabolic trough concentrator arrays in space

    NASA Astrophysics Data System (ADS)

    Stern, T. G.; Hayes, E. W.

    The design of a support structure for a space-power photovoltaic concentrator is described. The baseline concentrator uses miniaturized parabolic-trough mirror-radiators to illuminate solar cells at concentration ratios in the range from 10-40 x geometrical. Such a concentrator has unique pointing requirements in that high accuracy (2 degrees) is required in the axis of concentration, while the perpendicular axis allows greater pointing errors (10 degrees or more) with minimal power loss. The array structure was designed with the goal of meeting these pointing requirements under the constraints of given mirror lengths, payload-bay packaging envelopes, and operating disturbances. Structural design parameters included structure weight, array aperture efficiency (packing factor), and packaged volumetric efficiency. The proposed structure uses a rectangular grid of graphite composite beams backed by a rigidized truss to form a triangular cross-section. This design has projected specific mass as low as 1 kg/sq m for the structural fraction of the array, and can result in concentrator specific powers exceeding 60 W/kg using current technology.

  6. Measurement of Hydrogen Purge Rates in Parabolic Trough Receiver Tubes: Preprint

    SciTech Connect

    Glatzmaier, G. C.

    2010-10-01

    The purpose of this research is to investigate and develop methods to remove hydrogen centrally from commercial parabolic trough power plants. A mathematical model was developed that tracks the generation and transport of hydrogen within an operating plant. Modeling results predicted the steady-state partial pressure of hydrogen within the receiver annuli to be ~1 torr. This result agrees with measured values for the hydrogen partial pressure. The model also predicted the rate at which hydrogen must be actively removed from the expansion tank to reduce the partial pressure of hydrogen within the receiver annuli to less than 0.001 torr. Based on these results, mitigation strategies implemented at operating parabolic trough power plants can reduce hydrogen partial pressure to acceptable levels. Transient modeling predicted the time required to reduce the hydrogen partial pressures within receiver annuli to acceptable levels. The times were estimated as a function of bellows temperature, getter quantity, and getter temperature. This work also includes an experimental effort that will determine the time required to purge hydrogen from a receiver annulus with no getter.

  7. Water Use in Parabolic Trough Power Plants: Summary Results from WorleyParsons' Analyses

    SciTech Connect

    Turchi, C. S.; Wagner, M. J.; Kutscher, C. F.

    2010-12-01

    The National Renewable Energy Laboratory (NREL) contracted with WorleyParsons Group, Inc. to examine the effect of switching from evaporative cooling to alternative cooling systems on a nominal 100-MW parabolic trough concentrating solar power (CSP) plant. WorleyParsons analyzed 13 different cases spanning three different geographic locations (Daggett, California; Las Vegas, Nevada; and Alamosa, Colorado) to assess the performance, cost, and water use impacts of switching from wet to dry or hybrid cooling systems. NREL developed matching cases in its Solar Advisor Model (SAM) for each scenario to allow for hourly modeling and provide a comparison to the WorleyParsons results.Our findings indicate that switching from 100% wet to 100% dry cooling will result in levelized cost of electricity (LCOE) increases of approximately 3% to 8% for parabolic trough plants throughout most of the southwestern United States. In cooler, high-altitude areas like Colorado's San Luis Valley, WorleyParsons estimated the increase at only 2.5%, while SAM predicted a 4.4% difference. In all cases, the transition to dry cooling will reduce water consumption by over 90%. Utility time-of-delivery (TOD) schedules had similar impacts for wet- and dry-cooled plants, suggesting that TOD schedules have a relatively minor effect on the dry-cooling penalty.

  8. A review of Andasol 3 and perspective for parabolic trough CSP plants in South Africa

    NASA Astrophysics Data System (ADS)

    Dinter, Frank; Möller, Lucas

    2016-05-01

    Andasol 3 is a 50 MW parabolic trough concentrating solar power plant with thermal energy storage in Andalusia, southern Spain. Having started operating in 2011 as one of the first plants of its kind in Spain it has been followed by more than 50 in the country since. For the reason that CSP plants with storage have the potential to compete against fossil fuel fired plants much better than any other renewable energy source a long-term review of such a plant operating on a commercial scale is needed. With data at hand documenting Andasol 3's operation over the course of one year between July 2013 and June 2014 we intend to provide such a review. We calculated the plants overall efficiency, its capacity factor, the gross energy generation as well as auxiliary powers on a monthly basis to reflect upon its overall performance. It was also looked at the benefits caused by the thermal energy storage and especially how steadily and reliably the plant was able to operate. With basic background information about physical, geographical and meteorological aspects influencing the solar resource, its variation and a CSP plant's performance a qualitative estimation for a parabolic trough plant located in South Africa was made.

  9. An optimized model and test of the China's first high temperature parabolic trough solar receiver

    SciTech Connect

    Gong, Guangjie; Huang, Xinyan; Wang, Jun; Hao, Menglong

    2010-12-15

    The vacuum solar receiver is the key component of a parabolic trough solar plant, which plays a prominent role in the gross system efficiency. Recently, China's first high temperature vacuum receiver, Sanle-3 HCE, has been developed and produced by Southeast University and Sanle Electronic Group. Before being utilized in China's first parabolic trough solar plant, accurately estimating the thermal properties of this new receiver is important. This paper first establishes and optimizes a 1-D theoretical model at Matlab program to compute the receiver's major heat loss through glass envelope, and then systematically analyzes the major influence factors of heat loss. With the laboratorial steady state test stand, the heat losses of both good vacuum and non-vacuum Sanle-3 receivers were surveyed. Comparison shows the original 1-D model agrees with the ends covered test while remarkably deviating from end exposed test. For the purpose of identifying the influence of receiver's end to total heat loss, an additional 3-D model is built by CFD software to further investigate the different heat transfer processes of receiver's end components. The 3-D end model is verified by heating power and IR temperature distribution images in the test. Combining the optimized 1-D model with the new 3-D end model, the comparison with test data shows a good accordance. At the same time the heat loss curve and emittance curve of this new receiver are given and compared with those of several other existing receivers as references. (author)

  10. New Optical Evaluation Approach for Parabolic Trough Collectors: First-Principle OPTical Intercept Calculation

    SciTech Connect

    Zhu, G.; Lewandowski, A.

    2012-11-01

    A new analytical method -- First-principle OPTical Intercept Calculation (FirstOPTIC) -- is presented here for optical evaluation of trough collectors. It employs first-principle optical treatment of collector optical error sources and derives analytical mathematical formulae to calculate the intercept factor of a trough collector. A suite of MATLAB code is developed for FirstOPTIC and validated against theoretical/numerical solutions and ray-tracing results. It is shown that FirstOPTIC can provide fast and accurate calculation of intercept factors of trough collectors. The method makes it possible to carry out fast evaluation of trough collectors for design purposes. The FirstOPTIC techniques and analysis may be naturally extended to other types of CSP technologies such as linear-Fresnel collectors and central-receiver towers.

  11. Cleaning strategies for parabolic-trough solar-collector fields; guidelines for decisions

    SciTech Connect

    Bergeron, K.D.; Freese, J.M.

    1981-06-01

    This report is intended to assist the owner or operator of a parabolic trough solar collector system to decide on a cleaning strategy (equipment, materials, procedures, and schedules). The guidelines are based on information obtained in past research studies, as well as interviews with vendors and users of cleaning and water treatment equipment. The basic procedure recommended utilizes high pressure portable washing equipment. However, since the cleaning problem is so site-specific, no single, detailed approach can be specified. A systematic procedure for evaluating the particular requirements of a site is therefore given. This will allow the solar energy system operator to develop a cleaning strategy which is cost-effective because it is suited to local conditions.

  12. Utility-Scale Parabolic Trough Solar Systems: Performance Acceptance Test Guidelines, April 2009 - December 2010

    SciTech Connect

    Kearney, D.

    2011-05-01

    Prior to commercial operation, large solar systems in utility-size power plants need to pass a performance acceptance test conducted by the engineering, procurement, and construction (EPC) contractor or owners. In lieu of the present absence of ASME or other international test codes developed for this purpose, the National Renewable Energy Laboratory has undertaken the development of interim guidelines to provide recommendations for test procedures that can yield results of a high level of accuracy consistent with good engineering knowledge and practice. The Guidelines contained here are specifically written for parabolic trough collector systems with a heat-transport system using a high-temperature synthetic oil, but the basic principles are relevant to other CSP systems.

  13. Parabolic Trough Reference Plant for Cost Modeling with the Solar Advisor Model (SAM)

    SciTech Connect

    Turchi, C.

    2010-07-01

    This report describes a component-based cost model developed for parabolic trough solar power plants. The cost model was developed by the National Renewable Energy Laboratory (NREL), assisted by WorleyParsons Group Inc., for use with NREL's Solar Advisor Model (SAM). This report includes an overview and explanation of the model, two summary contract reports from WorleyParsons, and an Excel spreadsheet for use with SAM. The cost study uses a reference plant with a 100-MWe capacity and six hours of thermal energy storage. Wet-cooling and dry-cooling configurations are considered. The spreadsheet includes capital and operating cost by component to allow users to estimate the impact of changes in component costs.

  14. Techno-economic analysis of receiver replacement scenarios in a parabolic trough field

    NASA Astrophysics Data System (ADS)

    Röger, Marc; Lüpfert, Eckhard; Caron, Simon; Dieckmann, Simon

    2016-05-01

    The heat loss of an evacuated parabolic trough receiver of solar thermal power plants ranges typically between values below 150 and 200 W/m at 350°C. Defects, such as glass breakage by wind events and coating degradation, anti-reflection coating degradation or hydrogen accumulation in the annulus, decrease the annual electricity production. This study examines the effect of different receiver performance loss scenarios on the energetic and economic output of a modern 150-MWel-parabolic trough plant with 7.5-hours molten-salt storage, located in Ma'an, Jordan over the whole lifetime by modeling it in an extended version of the software greenius. Compared to the reference scenario, a wind event in year 5 (10, 15) causing glass envelope breakage and consequential degradation of the selective coating of 5.6% of the receivers reduces the electricity output by 5.1% (3.8%, 2.5%), the net present value is reduced by 36.5% (23.1%, 13.1%). The payback time of receiver replacement is only 0.7 years and hence this measure is recommended. The highest negative impact on performance and net present value of a project has the hydrogen accumulation scenario (50% of field affected) in event year 5 (10,15) reducing net electric output by 10.7% (8.1%, 5.4%) and the net present value by 77.0% (48.7%, 27.6%). Replacement of the receivers or even better an inexpensive repair solution is an energetically and economically sensible solution. The option of investing in premium receivers with Xe-capsule during the construction phase is a viable option if the surplus cost for premium receivers is lower than 10 to 20 percent.

  15. Simulation analysis of position error of parabolic trough concentrator mirror installation

    NASA Astrophysics Data System (ADS)

    Tian, Guo-liang; Yan, Bi-xi; Dong, Mingli; Wang, Jun; Sun, Peng

    2015-02-01

    The research showed the simulation of position error when assembling a reflective mirror of parabolic trough concentrator. The shape of a reflective mirror is like a parabolic cylinder model, relying on the back of the four-point mounted on a special setup, making it unable to move. Therefore, it is of great importance of the machining precision of special bracket. We need to analyze the influence of reflective mirror`s intercept factor in order to guide the processing precision. It is assumed that each reflective mirror is rigid, we have calculated the intercept factor of reflector with mounting points' random error of different standard deviation, comparing the simulating results with TRACEPRO. As a sequence, we can approve the feasibility of the algorithm, and give the effect of different random errors on the light-gathering efficiency. On the basis, we provide the machining accuracy of bracket. The simulation results show that when the mounting points' standard deviation of position error is less than 0.5 mm, the intercept factor of receiver has reached upwards of 92% with 60 mm diameter for receiver, which can satisfy the design requirements.

  16. Influence of spatiotemporally distributed irradiance data input on temperature evolution in parabolic trough solar field simulations

    NASA Astrophysics Data System (ADS)

    Bubolz, K.; Schenk, H.; Hirsch, T.

    2016-05-01

    Concentrating solar field operation is affected by shadowing through cloud movement. For line focusing systems the impact of varying irradiance has been studied before by several authors with simulations of relevant thermodynamics assuming spatially homogeneous irradiance or using artificial test signals. While today's simulation capabilities allow more and more a higher spatiotemporal resolution of plant processes there are only few studies on influence of spatially distributed irradiance due to lack of available data. Based on recent work on generating real irradiance maps with high spatial resolution this paper demonstrates their influence on solar field thermodynamics. For a case study an irradiance time series is chosen. One solar field section with several loops and collecting header is modeled for simulation purpose of parabolic trough collectors and oil as heat transfer medium. Assuming homogeneous mass flow distribution among all loops we observe spatially varying temperature characteristics. They are analysed without and with mass flow control and their impact on solar field control design is discussed. Finally, the potential of distributed irradiance data is outlined.

  17. Two-stage solar concentrators based on parabolic troughs: asymmetric versus symmetric designs.

    PubMed

    Schmitz, Max; Cooper, Thomas; Ambrosetti, Gianluca; Steinfeld, Aldo

    2015-11-20

    While nonimaging concentrators can approach the thermodynamic limit of concentration, they generally suffer from poor compactness when designed for small acceptance angles, e.g., to capture direct solar irradiation. Symmetric two-stage systems utilizing an image-forming primary parabolic concentrator in tandem with a nonimaging secondary concentrator partially overcome this compactness problem, but their achievable concentration ratio is ultimately limited by the central obstruction caused by the secondary. Significant improvements can be realized by two-stage systems having asymmetric cross-sections, particularly for 2D line-focus trough designs. We therefore present a detailed analysis of two-stage line-focus asymmetric concentrators for flat receiver geometries and compare them to their symmetric counterparts. Exemplary designs are examined in terms of the key optical performance metrics, namely, geometric concentration ratio, acceptance angle, concentration-acceptance product, aspect ratio, active area fraction, and average number of reflections. Notably, we show that asymmetric designs can achieve significantly higher overall concentrations and are always more compact than symmetric systems designed for the same concentration ratio. Using this analysis as a basis, we develop novel asymmetric designs, including two-wing and nested configurations, which surpass the optical performance of two-mirror aplanats and are comparable with the best reported 2D simultaneous multiple surface designs for both hollow and dielectric-filled secondaries. PMID:26836527

  18. Spectrum-splitting hybrid CSP-CPV solar energy system with standalone and parabolic trough plant retrofit applications

    NASA Astrophysics Data System (ADS)

    Orosz, Matthew; Zweibaum, Nicolas; Lance, Tamir; Ruiz, Maritza; Morad, Ratson

    2016-05-01

    Sunlight to electricity efficiencies of Parabolic Trough Collector (PTC) plants are typically on the order of 15%, while commercial solar Photovoltaic (PV) technologies routinely achieve efficiencies of greater than 20%, albeit with much higher conversion efficiencies of photons at the band gap. Hybridizing concentrating solar power and photovoltaic technologies can lead to higher aggregate efficiencies due to the matching of photons to the appropriate converter based on wavelength. This can be accomplished through spectral filtering whereby photons unusable or poorly utilitized by PV (IR and UV) are passed through to a heat collection element, while useful photons (VIS) are reflected onto a concentrating PV (CPV) receiver. The mechanical design and experimental validation of spectral splitting optics is described in conjunction with system level modeling and economic analysis. The implications of this architecture include higher efficiency, lower cost hybrid CSP-PV power systems, as well as the potential to retrofit existing PTC plants to boost their output by ~ 10% at a projected investment cost of less than 1 per additional net Watt and an IRR of 18%, while preserving the dispatchability of the CSP plant's thermal energy storage.

  19. Construction and thermal efficiency test of 145m and 165m SpaceTube large-aperture parabolic trough collector prototypes

    NASA Astrophysics Data System (ADS)

    Rubia, Salvador Valenzuela; Schramm, Markus; Yildiz, Hülya; Marcotte, Patrick; Casero, David Martín; Magee, John Sebastian

    2016-05-01

    During 2013-2014 two prototype SpaceTube® 8.2 parabolic trough collector [1] were built, optically tested, and interconnected into an existing parabolic trough thermal testing loop at Abengoa's Solucar Platform in Spain. After this startup process more than 500 hours of testing at nominal operating conditions (393 °C maximum temperature and 40 bar maximum pressure) were accumulated, allowing verification of the real-world thermal performance against model predictions. Measured performances of both collectors met the optical performance target and no significant optical or assembly deficiency was found, resulting in verification of the collector(s) as ready to commercialize.

  20. Direct steam generation in parabolic trough solar power plants: Numerical investigation of the transients and the control of a once-through system

    SciTech Connect

    Lippke, F.

    1996-02-01

    Direct steam generation (DSG) in parabolic troughs was first studied in the early 1980s by Murphy (1982) and Pederson (1982). Intensive research on DSG then started in 1988, when Luz identified this technology as the desired system for a future generation of its power plants. These R and D activities were not terminated by Luz`s demise in 1991, but have been continued by several institutes and companies in Europe as well as in Israel (Dagan et al., 1991, Mueller et al., 1992a, b, 1993, 1994). This paper concerns the dynamic reaction of the water-steam flow. In order to investigate this, a numerical simulation program of the water-steam flow. In order to investigate this, a numerical simulation program was developed at the ZSW. The numerical approach, its verification, and results of an extended study concerning the reaction and the control (ability) of a once-through DSG system at different weather conditions are presented.

  1. Direct steam generation in parabolic trough solar power plants -- Numerical investigation of the transients and the control of a once-through system

    SciTech Connect

    Lippke, F.

    1995-11-01

    Direct steam generation (DSG) in parabolic troughs was first studied in the early eighties by Murphy (1982) and Pederson (1982). Intensive research on DSG then started in 1988, when Luz identified this technology as the desired system for a future generation of its power plants. These R and D activities were not terminated on Luz`s demise in 1991, but have been continued by several institutes and companies in Europe as well as in Israel (Dagan et al., 1991, Mueller et al., 1992a,b, 1993, 1994). This paper concerns the dynamic reaction of the water-steam flow. In order to investigate this, a numerical simulation program was developed at the ZSW. The numerical approach, its verification, and results of an extended study concerning the reaction and the control(ability) of a once-through DSG system at different weather conditions are presented.

  2. Solar parabolic dish technology evaluation report

    NASA Technical Reports Server (NTRS)

    Lucas, J. W.

    1984-01-01

    The activities of the JPL Solar Thermal Power Systems Parabolic Dish Project for FY 1983 are summarized. Included are discussions on designs of module development including concentrator, receiver, and power conversion subsystems together with a separate discussion of field tests, Small Community Experiment system development, and tests at the Parabolic Dish Test Site.

  3. Solar Parabolic Dish Annual Technology Evaluation Report

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The activities of the JPL Solar Thermal Power Systems Parabolic Dish Project for FY 1982 are summarized. Included are discussions on designs of module development including their concentrator, receiver, and power conversion subsystems. Analyses and test results, along with progress on field tests, Small Community Experiment System development, and tests at the Parabolic Dish Test Site are also included.

  4. Nexant Parabolic Trough Solar Power Plant Systems Analysis; Task 1: Preferred Plant Size, 20 January 2005 - 31 December 2005

    SciTech Connect

    Kelly, B.

    2006-07-01

    The Rankine cycles for commercial parabolic trough solar projects range in capacity from 13.5 MWe at the Solar Electric Generating Station I (SEGS I) plant, to a maximum of 89 MWe at the SEGS VIII/IX plants. The series of SEGS projects showed a consistent reduction in the levelized energy cost due to a combination of improvements in collector field technology and economies of scale in both the Rankine cycle and the operation and maintenance costs. Nonetheless, the question of the optimum Rankine cycle capacity remains an open issue. The capacities of the SEGS VIII/IX plants were limited by Federal Energy Regulatory Commission and Public Utility Regulatory Policy Act requirements to a maximum net output of 80 MWe. Further improvements in the Rankine cycle efficiency, and economies of scale in both the capital and the operating cost, should be available at larger plant sizes. An analysis was conducted to determine the effect of Rankine cycle capacities greater than 80 MWe on the levelized energy cost. The study was conducted through the following steps: (1) Three gross cycle capacities of 88 MWe, 165 MWe, and 220 MWe were selected. (2) Three Rankine cycle models were developed using the GateCycle program. The models were based on single reheat turbine cycles, with main steam conditions of 1,450 lb{sub f}/in{sup 2} and 703 F, and reheat steam conditions of 239 lb{sub f}/in{sup 2} and 703 F. The feedwater heater system consisted of 5 closed heaters and 1 open deaerating heater. The design condenser pressure was 2.5 in. HgA. (3) The optimization function within Excelergy was used to determine the preferred solar multiple for each plant. Two cases were considered for each plant: (a) a solar-only project without thermal storage, and (b) a solar-fossil hybrid project, with 3 hours of thermal storage and a heat transport fluid heater fired by natural gas. (4) For each of the 6 cases, collector field geometries, heat transport fluid pressure losses, and heat transport pump

  5. LCA (Life Cycle Assessment) of Parabolic Trough CSP: Materials Inventory and Embodied GHG Emissions from Two-Tank Indirect and Thermocline Thermal Storage (Presentation)

    SciTech Connect

    Heath, G.; Burkhardt, J.; Turchi, C.; Decker, T.; Kutscher, C.

    2009-07-20

    In the United States, concentrating solar power (CSP) is one of the most promising renewable energy (RE) technologies for reduction of electric sector greenhouse gas (GHG) emissions and for rapid capacity expansion. It is also one of the most price-competitive RE technologies, thanks in large measure to decades of field experience and consistent improvements in design. One of the key design features that makes CSP more attractive than many other RE technologies, like solar photovoltaics and wind, is the potential for including relatively low-cost and efficient thermal energy storage (TES), which can smooth the daily fluctuation of electricity production and extend its duration into the evening peak hours or longer. Because operational environmental burdens are typically small for RE technologies, life cycle assessment (LCA) is recognized as the most appropriate analytical approach for determining their environmental impacts of these technologies, including CSP. An LCA accounts for impacts from all stages in the development, operation, and decommissioning of a CSP plant, including such upstream stages as the extraction of raw materials used in system components, manufacturing of those components, and construction of the plant. The National Renewable Energy Laboratory (NREL) is undertaking an LCA of modern CSP plants, starting with those of parabolic trough design.

  6. Numerical study on coupled fluid flow and heat transfer process in parabolic trough solar collector tube

    SciTech Connect

    Tao, Y.B.; He, Y.L.

    2010-10-15

    A unified two-dimensional numerical model was developed for the coupled heat transfer process in parabolic solar collector tube, which includes nature convection, forced convection, heat conduction and fluid-solid conjugate problem. The effects of Rayleigh number (Ra), tube diameter ratio and thermal conductivity of the tube wall on the heat transfer and fluid flow performance were numerically analyzed. The distributions of flow field, temperature field, local Nu and local temperature gradient were examined. The results show that when Ra is larger than 10{sup 5}, the effects of nature convection must be taken into account. With the increase of tube diameter ratio, the Nusselt number in inner tube (Nu{sub 1}) increases and the Nusselt number in annuli space (Nu{sub 2}) decreases. With the increase of tube wall thermal conductivity, Nu{sub 1} decreases and Nu{sub 2} increases. When thermal conductivity is larger than 200 W/(m K), it would have little effects on Nu and average temperatures. Due to the effect of the nature convection, along the circumferential direction (from top to down), the temperature in the cross-section decreases and the temperature gradient on inner tube surface increases at first. Then, the temperature and temperature gradients would present a converse variation at {theta} near {pi}. The local Nu on inner tube outer surface increases along circumferential direction until it reaches a maximum value then it decreases again. (author)

  7. Reducing the Cost of Thermal Energy Storage for Parabolic Trough Solar Power Plants

    SciTech Connect

    Gawlik, Keith

    2013-06-25

    Thermal energy storage systems using phase change materials were evaluated for trough systems that use oil, steam, and high temperature salts as heat transfer fluids. A variety of eutectic salts and metal alloys were considered as phase change materials in a cascaded arrangement. Literature values of specific heat, latent heat, density, and other thermophysical properties were used in initial analyses. Testing laboratories were contracted to measure properties for candidate materials for comparison to the literature and for updating the models. A TRNSYS model from Phase 1 was further developed for optimizing the system, including a novel control algorithm. A concept for increasing the bulk thermal conductivity of the phase change system was developed using expanded metal sheets. Outside companies were contracted to design and cost systems using platecoil heat exchangers immersed in the phase change material. Laboratory evaluations of the one-dimensional and three-dimensional behavior of expanded metal sheets in a low conductivity medium were used to optimize the amount of thermal conductivity enhancement. The thermal energy storage systems were compared to baseline conventional systems. The best phase change system found in this project, which was for the high temperature plant, had a projected cost of $25.2 per kWhth, The best system also had a cost that was similar to the base case, a direct two-tank molten salt system.

  8. Generation of a Parabolic Trough Collector Efficiency Curve from Separate Measurements of Outdoor Optical Efficiency and Indoor Receiver Heat Loss

    SciTech Connect

    Kutscher, C.; Burkholder, F.; Stynes, J. K.

    2012-02-01

    The thermal efficiency of a parabolic trough collector is a function of both the fraction of direct normal radiation absorbed by the receiver (the optical efficiency) and the heat lost to the environment when the receiver is at operating temperature. The thermal efficiency can be determined by testing the collector under actual operating conditions or by separately measuring these two components. This paper describes how outdoor measurement of the optical efficiency is combined with laboratory measurements of receiver heat loss to obtain the thermal efficiency curve. This paper describes this approach and also makes the case that there are advantages to plotting collector efficiency versus the difference between the operating temperature and the ambient temperature at which the receiver heat loss was measured divided by radiation to a fractional power (on the order of 1/3 but obtained via data regression) - as opposed to the difference between operating and ambient temperatures divided by the radiation. The results are shown to be robust over wide ranges of ambient temperature, sky temperature, and wind speed.

  9. Life Cycle Assessment of a Parabolic Trough Concentrating Solar Power Plant and Impacts of Key Design Alternatives: Preprint

    SciTech Connect

    Heath, G. A.; Burkhardt, J. J.; Turchi, C. S.

    2011-09-01

    Climate change and water scarcity are important issues for today's power sector. To inform capacity expansion decisions, hybrid life cycle assessment is used to evaluate a reference design of a parabolic trough concentrating solar power (CSP) facility located in Daggett, California, along four sustainability metrics: life cycle greenhouse gas (GHG) emissions, water consumption, cumulative energy demand (CED), and energy payback time (EPBT). This wet-cooled, 103 MW plant utilizes mined nitrate salts in its two-tank, thermal energy storage (TES) system. Design alternatives of dry-cooling, a thermocline TES, and synthetically-derived nitrate salt are evaluated. During its life cycle, the reference CSP plant is estimated to emit 26 g CO2eq per kWh, consume 4.7 L/kWh of water, and demand 0.40 MJeq/kWh of energy, resulting in an EPBT of approximately 1 year. The dry-cooled alternative is estimated to reduce life cycle water consumption by 77% but increase life cycle GHG emissions and CED by 8%. Synthetic nitrate salts may increase life cycle GHG emissions by 52% compared to mined. Switching from two-tank to thermocline TES configuration reduces life cycle GHG emissions, most significantly for plants using synthetically-derived nitrate salts. CSP can significantly reduce GHG emissions compared to fossil-fueled generation; however, dry-cooling may be required in many locations to minimize water consumption.

  10. Life cycle assessment of a parabolic trough concentrating solar power plant and the impacts of key design alternatives.

    PubMed

    Burkhardt, John J; Heath, Garvin A; Turchi, Craig S

    2011-03-15

    Climate change and water scarcity are important issues for today's power sector. To inform capacity expansion decisions, hybrid life cycle assessment is used to evaluate a reference design of a parabolic trough concentrating solar power (CSP) facility located in Daggett, CA, along four sustainability metrics: life cycle (LC) greenhouse gas (GHG) emissions, water consumption, cumulative energy demand (CED), and energy payback time (EPBT). This wet-cooled, 103 MW plant utilizes mined nitrates salts in its two-tank, thermal energy storage (TES) system. Design alternatives of dry-cooling, a thermocline TES, and synthetically derived nitrate salt are evaluated. During its LC, the reference CSP plant is estimated to emit 26 g of CO(2eq) per kWh, consume 4.7 L/kWh of water, and demand 0.40 MJ(eq)/kWh of energy, resulting in an EPBT of approximately 1 year. The dry-cooled alternative is estimated to reduce LC water consumption by 77% but increase LC GHG emissions and CED by 8%. Synthetic nitrate salts may increase LC GHG emissions by 52% compared to mined. Switching from two-tank to thermocline TES configuration reduces LC GHG emissions, most significantly for plants using synthetically derived nitrate salts. CSP can significantly reduce GHG emissions compared to fossil-fueled generation; however, dry-cooling may be required in many locations to minimize water consumption. PMID:21391722

  11. Two new methods used to simulate the circumferential solar flux density concentrated on the absorber of a parabolic trough solar collector

    NASA Astrophysics Data System (ADS)

    Guo, Minghuan; Wang, Zhifeng; Sun, Feihu

    2016-05-01

    The optical efficiencies of a solar trough concentrator are important to the whole thermal performance of the solar collector, and the outer surface of the tube absorber is a key interface of energy flux. So it is necessary to simulate and analyze the concentrated solar flux density distributions on the tube absorber of a parabolic trough solar collector for various sun beam incident angles, with main optical errors considered. Since the solar trough concentrators are linear focusing, it is much of interest to investigate the solar flux density distribution on the cross-section profile of the tube absorber, rather than the flux density distribution along the focal line direction. Although a few integral approaches based on the "solar cone" concept were developed to compute the concentrated flux density for some simple trough concentrator geometries, all those integral approaches needed special integration routines, meanwhile, the optical parameters and geometrical properties of collectors also couldn't be changed conveniently. Flexible Monte Carlo ray trace (MCRT) methods are widely used to simulate the more accurate concentrated flux density distribution for compound parabolic solar trough concentrators, while generally they are quite time consuming. In this paper, we first mainly introduce a new backward ray tracing (BRT) method combined with the lumped effective solar cone, to simulate the cross-section flux density on the region of interest of the tube absorber. For BRT, bundles of rays are launched at absorber-surface points of interest, directly go through the glass cover of the absorber, strike on the uniformly sampled mirror segment centers in the close-related surface region of the parabolic reflector, and then direct to the effective solar cone around the incident sun beam direction after the virtual backward reflection. All the optical errors are convoluted into the effective solar cone. The brightness distribution of the effective solar cone is supposed

  12. Testing thermocline filler materials and molten-salt heat transfer fluids for thermal energy storage systems used in parabolic trough solar power plants.

    SciTech Connect

    Kelly, Michael James; Hlava, Paul Frank; Brosseau, Douglas A.

    2004-07-01

    Parabolic trough power systems that utilize concentrated solar energy to generate electricity are a proven technology. Industry and laboratory research efforts are now focusing on integration of thermal energy storage as a viable means to enhance dispatchability of concentrated solar energy. One option to significantly reduce costs is to use thermocline storage systems, low-cost filler materials as the primary thermal storage medium, and molten nitrate salts as the direct heat transfer fluid. Prior thermocline evaluations and thermal cycling tests at the Sandia National Laboratories' National Solar Thermal Test Facility identified quartzite rock and silica sand as potential filler materials. An expanded series of isothermal and thermal cycling experiments were planned and implemented to extend those studies in order to demonstrate the durability of these filler materials in molten nitrate salts over a range of operating temperatures for extended timeframes. Upon test completion, careful analyses of filler material samples, as well as the molten salt, were conducted to assess long-term durability and degradation mechanisms in these test conditions. Analysis results demonstrate that the quartzite rock and silica sand appear able to withstand the molten salt environment quite well. No significant deterioration that would impact the performance or operability of a thermocline thermal energy storage system was evident. Therefore, additional studies of the thermocline concept can continue armed with confidence that appropriate filler materials have been identified for the intended application.

  13. Solar parabolic dish thermal power systems - Technology and applications

    NASA Technical Reports Server (NTRS)

    Lucas, J. W.; Marriott, A. T.

    1979-01-01

    Activities of two projects at JPL in support of DOE's Small Power Systems Program are reported. These two projects are the Point-Focusing Distributed Receiver (PFDR) Technology Project and the Point-Focusing Thermal and Electric Applications (PFTEA) Project. The PFDR Technology Project's major activity is developing the technology of solar concentrators, receivers and power conversion subsystems suitable for parabolic dish or point-focusing distributed receiver power systems. Other PFDR activities include system integration and cost estimation under mass production, as well as the testing of the hardware. The PFTEA Project's first major activity is applications analysis, that is seeking ways to introduce PFDR systems into appropriate user sectors. The second activity is systems engineering and development wherein power plant systems are analyzed for specific applications. The third activity is the installation of a series of engineering experiments in various user environments to obtain actual operating experience

  14. Solar parabolic dish technology annual evaluation report. Fiscal year 1983

    SciTech Connect

    Not Available

    1984-04-15

    This report summarizes the activities of the JPL Solar Thermal Power Systems Parabolic Dish Project for FY 1983. Included are discussions on designs of module development including their concentrator, receiver, and power conversion subsystem together with a separate discussion of concentrator development. Analyses and test results, along with progress on field tests, Small Community Experiment system development, and tests at the Parabolic Dish Test Site are also included.

  15. Solar thermal technology evaluation, fiscal year 1982. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Three primary solar concepts the central receiver, parabolic dish, and parabolic trough are investigated. To a lesser extent, the hemispherical bowl and salt-gradient solar pond are also being studied. Each technology is described.

  16. Optimized molten salt receivers for ultimate trough solar fields

    NASA Astrophysics Data System (ADS)

    Riffelmann, Klaus-J.; Richert, Timo; Kuckelkorn, Thomas

    2016-05-01

    Today parabolic trough collectors are the most successful concentrating solar power (CSP) technology. For the next development step new systems with increased operation temperature and new heat transfer fluids (HTF) are currently developed. Although the first power tower projects have successfully been realized, up to now there is no evidence of an all-dominant economic or technical advantage of power tower or parabolic trough. The development of parabolic trough technology towards higher performance and significant cost reduction have led to significant improvements in competitiveness. The use of molten salt instead of synthetic oil as heat transfer fluid will bring down the levelized costs of electricity (LCOE) even further while providing dispatchable energy with high capacity factors. FLABEG has developed the Ultimate TroughTM (UT) collector, jointly with sbp Sonne GmbH and supported by public funds. Due to its validated high optical accuracy, the collector is very suitable to operate efficiently at elevated temperatures up to 550 °C. SCHOTT will drive the key-innovations by introducing the 4th generation solar receiver that addresses the most significant performance and cost improvement measures. The new receivers have been completely redesigned to provide a product platform that is ready for high temperature operation up to 550 °C. Moreover distinct product features have been introduced to reduce costs and risks in solar field assembly and installation. The increased material and design challenges incurred with the high temperature operation have been reflected in sophisticated qualification and validation procedures.

  17. Parabolic Trouogh Optical Characterization at the National Renewable Energy Laboratory

    SciTech Connect

    Wendelin, T. J.

    2005-01-01

    Solar parabolic trough power plant projects are soon to be implemented in the United States and internationally. In addition to these new projects, parabolic trough power plants totaling approximately 350 MW already exist within the United States and have operated for close to 20 years. As such, the status of the technology exists within several different phases. Theses phases include R&D, manufacturing and installation, and operations and maintenance. One aspect of successful deployment of this technology is achieving and maintaining optical performance. Different optical tools are needed to assist in improving initial designs, provide quality control during manufacture and assembly, and help maintain performance during operation. This paper discusses several such tools developed at SunLab (a joint project of the National Renewable Laboratory and Sandia National Laboratories) for these purposes. Preliminary testing results are presented. Finally, plans for further tool development are discussed.

  18. Summary assessment of solar thermal parabolic dish technology for electrical power generation

    NASA Technical Reports Server (NTRS)

    Penda, P. L.; Fujita, T.; Lucas, J. W.

    1985-01-01

    An assessment is provided of solar thermal parabolic dish technology for electrical power generation. The assessment is based on the development program undertaken by the Jet Propulsion Laboratory for the U.S. Department of Energy and covers the period from the initiation of the program in 1976 through mid-1984. The program was founded on developing components and subsystems that are integrated into parabolic dish power modules for test and evaluation. The status of the project is summarized in terms of results obtained through testing of modules, and the implications of these findings are assessed in terms of techno-economic projections and market potential. The techno-economic projections are based on continuation of an evolutionary technological development program and are related to the accomplishments of the program as of mid-1984. The accomplishments of the development effort are summarized for each major subsystem including concentrators, receivers, and engines. The ramifications of these accomplishments are assessed in the context of developmental objectives and strategies.

  19. Summary assessment of solar thermal parabolic dish technology for electrical power generation

    NASA Astrophysics Data System (ADS)

    Penda, P. L.; Fujita, T.; Lucas, J. W.

    1985-09-01

    An assessment is provided of solar thermal parabolic dish technology for electrical power generation. The assessment is based on the development program undertaken by the Jet Propulsion Laboratory for the U.S. Department of Energy and covers the period from the initiation of the program in 1976 through mid-1984. The program was founded on developing components and subsystems that are integrated into parabolic dish power modules for test and evaluation. The status of the project is summarized in terms of results obtained through testing of modules, and the implications of these findings are assessed in terms of techno-economic projections and market potential. The techno-economic projections are based on continuation of an evolutionary technological development program and are related to the accomplishments of the program as of mid-1984. The accomplishments of the development effort are summarized for each major subsystem including concentrators, receivers, and engines. The ramifications of these accomplishments are assessed in the context of developmental objectives and strategies.

  20. Solar trough systems

    SciTech Connect

    1998-04-01

    Trough systems predominate among today`s commercial solar power plants. All together, nine trough power plants, also called Solar Energy Generating Systems (SEGS), were built in the 1980s in the Mojave Desert near Barstow, California. These plants have a combined capacity of 354 megawatts (MW) and today generate enough electricity to meet the needs of approximately 500,000 people. Trough systems convert the heat from the sun into electricity. Because of their parabolical shape, troughs can focus the sun at 30--60 times its normal intensity on a receiver pipe located along the focal line of the trough. Synthetic oil captures this heat as the oil circulates through the pipe, reaching temperatures as high as 390 C (735 F). The hot oil is pumped to a generating station and routed through a heat exchanger to produce steam. Finally, electricity is produced in a conventional steam turbine. In addition to operating on solar energy the SEGS plants are configured as hybrids to operate on natural gas on cloudy days or after dark. Natural gas provides 25% of the output of the SEGS plants.

  1. The small community solar thermal power experiment. Parabolic dish technology for industrial process heat application

    NASA Technical Reports Server (NTRS)

    Polzien, R. E.; Rodriguez, D.

    1981-01-01

    Aspects of incorporating a thermal energy transport system (ETS) into a field of parabolic dish collectors for industrial process heat (IPH) applications were investigated. Specific objectives are to: (1) verify the mathematical optimization of pipe diameters and insulation thicknesses calculated by a computer code; (2) verify the cost model for pipe network costs using conventional pipe network construction; (3) develop a design and the associated production costs for incorporating risers and downcomers on a low cost concentrator (LCC); (4) investigate the cost reduction of using unconventional pipe construction technology. The pipe network design and costs for a particular IPH application, specifically solar thermally enhanced oil recovery (STEOR) are analyzed. The application involves the hybrid operation of a solar powered steam generator in conjunction with a steam generator using fossil fuels to generate STEOR steam for wells. It is concluded that the STEOR application provides a baseline pipe network geometry used for optimization studies of pipe diameter and insulation thickness, and for development of comparative cost data, and operating parameters for the design of riser/downcomer modifications to the low cost concentrator.

  2. Solar photovoltaic reflective trough collection structure

    SciTech Connect

    Anderson, Benjamin J.; Sweatt, William C.; Okandan, Murat; Nielson, Gregory N.

    2015-11-19

    A photovoltaic (PV) solar concentration structure having at least two troughs encapsulated in a rectangular parallelepiped optical plastic structure, with the troughs filled with an optical plastic material, the troughs each having a reflective internal surface and approximately parabolic geometry, and the troughs each including photovoltaic cells situated so that light impinging on the optical plastic material will be concentrated onto the photovoltaic cells. Multiple structures can be connected to provide a solar photovoltaic collection system that provides portable, efficient, low-cost electrical power.

  3. Detailed Physical Trough Model for NREL's Solar Advisor Model: Preprint

    SciTech Connect

    Wagner, M. J.; Blair, N.; Dobos, A.

    2010-10-01

    Solar Advisor Model (SAM) is a free software package made available by the National Renewable Energy Laboratory (NREL), Sandia National Laboratory, and the US Department of Energy. SAM contains hourly system performance and economic models for concentrating solar power (CSP) systems, photovoltaic, solar hot-water, and generic fuel-use technologies. Versions of SAM prior to 2010 included only the parabolic trough model based on Excelergy. This model uses top-level empirical performance curves to characterize plant behavior, and thus is limited in predictive capability for new technologies or component configurations. To address this and other functionality challenges, a new trough model; derived from physical first principles was commissioned to supplement the Excelergy-based empirical model. This new 'physical model' approaches the task of characterizing the performance of the whole parabolic trough plant by replacing empirical curve-fit relationships with more detailed calculations where practical. The resulting model matches the annual performance of the SAM empirical model (which has been previously verified with plant data) while maintaining run-times compatible with parametric analysis, adding additional flexibility in modeled system configurations, and providing more detailed performance calculations in the solar field, power block, piping, and storage subsystems.

  4. OUT Success Stories: Solar Trough Power Plants

    DOE R&D Accomplishments Database

    Jones, J.

    2000-08-01

    The Solar Electric Generating System (SEGS) plants use parabolic-trough solar collectors to capture the sun's energy and convert it to heat. The SEGS plants range in capacity from 13.8 to 80 MW, and they were constructed to meet Southern California Edison Company's periods of peak power demand.

  5. Commercialization of parabolic dish systems

    NASA Technical Reports Server (NTRS)

    Washom, B.

    1982-01-01

    The impact of recent federal tax and regulatory legislation on the commercialization of parabolic solar reflector technology is assessed. Specific areas in need of technical or economic improvement are noted.

  6. Commercialization of parabolic dish systems

    NASA Astrophysics Data System (ADS)

    Washom, B.

    1982-07-01

    The impact of recent federal tax and regulatory legislation on the commercialization of parabolic solar reflector technology is assessed. Specific areas in need of technical or economic improvement are noted.

  7. Technical Manual for the SAM Physical Trough Model

    SciTech Connect

    Wagner, M. J.; Gilman, P.

    2011-06-01

    NREL, in conjunction with Sandia National Lab and the U.S Department of Energy, developed the System Advisor Model (SAM) analysis tool for renewable energy system performance and economic analysis. This paper documents the technical background and engineering formulation for one of SAM's two parabolic trough system models in SAM. The Physical Trough model calculates performance relationships based on physical first principles where possible, allowing the modeler to predict electricity production for a wider range of component geometries than is possible in the Empirical Trough model. This document describes the major parabolic trough plant subsystems in detail including the solar field, power block, thermal storage, piping, auxiliary heating, and control systems. This model makes use of both existing subsystem performance modeling approaches, and new approaches developed specifically for SAM.

  8. Review of polymer usage in the development of prototype troughs by Sandia National Laboratories, Albuquerque (SNLA)

    NASA Astrophysics Data System (ADS)

    Clark, N. H.; Champion, R. L.

    The use of polymers as structural materials, adhesives, and coatings for parabolic trough reflectors is discussed. Four design concepts for producing panel reflectors are described relative to the role polymers play in them.

  9. Life Cycle Greenhouse Gas Emissions of Trough and Tower Concentrating Solar Power Electricity Generation: Systematic Review and Harmonization

    SciTech Connect

    Burkhardt, J. J.; Heath, G.; Cohen, E.

    2012-04-01

    In reviewing life cycle assessment (LCA) literature of utility-scale concentrating solar power (CSP) systems, this analysis focuses on reducing variability and clarifying the central tendency of published estimates of life cycle greenhouse gas (GHG) emissions through a meta-analytical process called harmonization. From 125 references reviewed, 10 produced 36 independent GHG emissions estimates passing screens for quality and relevance: 19 for parabolic trough (trough) technology and 17 for power tower (tower) technology. The interquartile range (IQR) of published estimates for troughs and towers were 83 and 20 grams of carbon dioxide equivalent per kilowatt-hour (g CO2-eq/kWh),1 respectively; median estimates were 26 and 38 g CO2-eq/kWh for trough and tower, respectively. Two levels of harmonization were applied. Light harmonization reduced variability in published estimates by using consistent values for key parameters pertaining to plant design and performance. The IQR and median were reduced by 87% and 17%, respectively, for troughs. For towers, the IQR and median decreased by 33% and 38%, respectively. Next, five trough LCAs reporting detailed life cycle inventories were identified. The variability and central tendency of their estimates are reduced by 91% and 81%, respectively, after light harmonization. By harmonizing these five estimates to consistent values for global warming intensities of materials and expanding system boundaries to consistently include electricity and auxiliary natural gas combustion, variability is reduced by an additional 32% while central tendency increases by 8%. These harmonized values provide useful starting points for policy makers in evaluating life cycle GHG emissions from CSP projects without the requirement to conduct a full LCA for each new project.

  10. Rinse trough with improved flow

    DOEpatents

    O`Hern, T.J.; Grasser, T.W.

    1998-08-11

    Novel rinse troughs accomplish thorough uniform rinsing. The troughs are suitable for one or more essentially planar objects having substantially the same shape. The troughs ensure that each surface is rinsed uniformly. The new troughs provide uniform rinse fluid flow over the objects` surfaces to accomplish a more thorough rinse than prior art troughs. 5 figs.

  11. Rinse trough with improved flow

    DOEpatents

    O'Hern, Timothy J.; Grasser, Thomas W.

    1998-01-01

    Novel rinse troughs accomplish thorough uniform rinsing. The troughs are suitable for one or more essentially planar objects having substantially the same shape. The troughs ensure that each surface is rinsed uniformly. The new troughs provide uniform rinse fluid flow over the objects' surfaces to accomplish a more thorough rinse than prior art troughs.

  12. The light ion trough.

    NASA Technical Reports Server (NTRS)

    Taylor, H. A., Jr.

    1972-01-01

    A distinct feature of the ion composition results from the OGO-2, 4 and 6 satellites is the light ion trough, wherein the mid-latitude concentrations of H+ and He+ decrease sharply with latitude. In contrast to the 'main trough' in electron density observed primarily as a nightside phenomenon, the light ion trough persists during both day and night. For daytime winter hemisphere conditions and for all seasons during night, the mid-latitude light ion concentration decrease is a pronounced feature. In the dayside summer and equinox hemispheres, the rate of light ion decrease with latitude is comparatively gradual, and the trough boundary is less well defined, particularly for quiet magnetic conditions. In response to magnetic storms, the light ion trough minimum moves equatorward, and deepens, consistent with earlier evidence of the contraction of the plasmasphere in response to storm time enhancements in magnetospheric plasma convection.

  13. Cerberus Fossae Troughs

    NASA Technical Reports Server (NTRS)

    2004-01-01

    11 October 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows portions of two of the Cerberus Fossae troughs, their dark-toned interiors, and dark wind streaks formed from material blowing out of the troughs. The wind streaks indicate winds that blew from the northeast (upper right) toward the southwest (lower left). The crust of Mars expanded and split to form the troughs. These features are located near 6.6oN, 187.2oW. The image covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

  14. Directed flow fluid rinse trough

    DOEpatents

    Kempka, Steven N.; Walters, Robert N.

    1996-01-01

    Novel rinse troughs accomplish thorough uniform rinsing. The tanks are suitable for one or more essentially planar items having substantially the same shape. The troughs ensure that each surface is rinsed uniformly. The new troughs also require less rinse fluid to accomplish a thorough rinse than prior art troughs.

  15. Directed flow fluid rinse trough

    DOEpatents

    Kempka, S.N.; Walters, R.N.

    1996-07-02

    Novel rinse troughs accomplish thorough uniform rinsing. The tanks are suitable for one or more essentially planar items having substantially the same shape. The troughs ensure that each surface is rinsed uniformly. The new troughs also require less rinse fluid to accomplish a thorough rinse than prior art troughs. 9 figs.

  16. Solar Thermal Power Systems parabolic dish project

    NASA Technical Reports Server (NTRS)

    Truscello, V. C.

    1981-01-01

    The status of the Solar Thermal Power Systems Project for FY 1980 is summarized. Included is: a discussion of the project's goals, program structure, and progress in parabolic dish technology. Analyses and test results of concentrators, receivers, and power converters are discussed. Progress toward the objectives of technology feasibility, technology readiness, system feasibility, and system readiness are covered.

  17. State-of-the-art review of low-cost collector technologies

    NASA Astrophysics Data System (ADS)

    Tolbert, W. A.

    1981-06-01

    This report provides a brief but concise review of low-cost solar collector technologies and their potential for application within the military. The report covers low-cost, light-weight concepts for flat-plate collectors, parabolic trough collectors, heliostats and parabolic dish collectors. In addition, several criteria were evaluated with respect to low-cost collector technologies. These included reliability, maintainability, survivability, mobility/erectibility, environmental impact and economics. Research and development requirements and ongoing activities were also summarized. This report documents one of several ongoing state-of-the-art reviews of solar technologies performed by an Air Force liaison office with the Department of Energy.

  18. Student Parabolic Flight Campaign

    NASA Astrophysics Data System (ADS)

    Sentse, N. S. M.; Ockels, W. J.

    2002-01-01

    After the successful Student Parabolic Flight Campaigns held in 1994 and 1995, the European Space Agency resumed their organisation of parabolic flight campaigns, dedicated to students of all ESA member states on an annual basis. The Student Parabolic Flight Campaigns are in order to promote microgravity research among students, tomorrow's scientists, since students can bring new ideas and initiatives to the space industry. Already four parabolic flight campaigns have flown and the 2002 student parabolic flight campaign has just flown in September. Thirty experiments are selected to fly in each campaign using the criteria of originality, demonstration of zero G, technical complexity and outreach performed by the team. Each experiment team consists of four university students. This is the chance for students to have the real weightlessness experience on board of the A300 ZERO-G aircraft. In addition, for one or two of the very best student experiments from each campaign, there will be the possibility to re-fly themselves and their experiment on ESA's Professional Parabolic Flight Campaigns. Eventually, one student experiment will be flying to the International Space Station. Conclusively, students' experiments can get fundamentally new and exciting results!

  19. Photovoltaic concentrator technology development project. Sixth project integration meeting

    SciTech Connect

    1980-10-01

    Thirty-three abstracts and short papers are presented which describe the current status of research, development, and demonstration of concentrator solar cell technology. Solar concentrators discussed include the parabolic trough, linear focus Fresnel lens, point focus Fresnel lens, and the parabolic dish. Solar cells studied include silicon, GaAs, and AlGaAs. Research on multiple junction cells, combined photovoltaic/thermal collectors, back contact solar cells, and beam splitter modules is described. Concentrator solar cell demonstration programs are reported. Contractor status summaries are given for 33 US DOE concentrator solar cell contracts; a description of the project, project status, and key results to date is included. (WHK)

  20. Using Technology (Instead of Calculus) To Derive the Law of Reflection for Parabolic Mirrors from Fermat's Principle of Least Time.

    ERIC Educational Resources Information Center

    Helfgott, Michel; Simonsen, Linda M.

    1998-01-01

    Presents an activity to investigate physico-mathematical concepts and provide mathematics arguments that are very close to a proof with the advent and availability of powerful technology. Demonstrates without using calculus how the law of reflection for parabolas is derived from Fermat's principle of least time. (ASK)

  1. The magnetospheric trough

    SciTech Connect

    Thomsen, M.F.; McComas, D.J.; Elphic, R.C.; Borovsky, J.E.

    1997-03-04

    The authors review the history of the concepts of the magnetospheric cold-ion trough and hot-electron trough and conclude that the two regions are actually essentially the same. The magnetospheric trough may be viewed as a temporal state in the evolution of convecting flux tubes. These flux tubes are in contact with the earth`s upper atmosphere which acts both as a sink for precipitating hot plasma sheet electrons and as a source for the cold ionospheric plasma leading to progressive depletion of the plasma sheet and refilling with cold plasma. Geosynchronous plasma observations show that the rate of loss of plasma-sheet electron energy density is commensurate with the precipitating electron flux at the low-latitude edge of the diffuse aurora. The rate at which geosynchronous flux tubes fill with cold ionospheric plasma is found to be consistent with previous estimates of early-time refilling. Geosynchronous observations further indicate that both Coulomb collisions and wave-particle effects probably play a role in trapping ionospheric material in the magnetosphere.

  2. Antireflection Pyrex envelopes for parabolic solar collectors

    NASA Astrophysics Data System (ADS)

    McCollister, H. L.; Pettit, R. B.

    1983-11-01

    Antireflective (AR) coatings, applied to the glass envelopes used in parabolic trough solar collectors around the receiver tube in order to reduce thermal losses, can increase solar transmittance by 7 percent. An AR surface has been formed on Pyrex by first heat treating the glass to cause a compositional phase separation, removing a surface layer after heat treatment through the use of a preetching solution, and finally etching in a solution that contains hydrofluorosilic and ammonium bifluoride acids. AR-coated samples with solar transmittance values of more than 0.97, by comparison to an untreated sample value of 0.91, have been obtained for the 560-630 C range of heat treatment temperatures. Optimum values have also been determined for the other processing parameters.

  3. Line-focus solar thermal energy technology development. FY 79 annual report for Department 4720

    SciTech Connect

    Bergeron, K D; Champion, R L; Hunke, R W

    1980-04-01

    The primary role of the Solar Energy Projects Department II (4720) is the development, evaluation, and testing of line-focus solar thermal technology. This report of FY 79 progress and accomplishments is divided into two parts: (1) Component and Subsystem Development including the design and analysis of collector modules, their components, and associated materials and processes, and (2) Systems and Applications Development, involving larger configurations of solar thermal line-focus systems. The emphasis is on parabolic troughs, but significant efforts on hemispherical bowls, compound parabolic collectors, and dishes for the Solar Total Energy Project are also described.

  4. Parabolic torus transreflector antenna

    NASA Astrophysics Data System (ADS)

    Diaz, L. M.; Smith, M. S.

    1984-12-01

    The possible scan rate of conventional radar antennas using parabolic dishes is limited to about 60 rev/min. This limitation is related to mechanical rotation requirements. Many radar applications require high data renewal rates, including short-range defense systems and systems for reduction of sea clutter. Faster scan rates can be obtained by using phased arrays and electronic scanning. However, the use of the required equipment introduces considerable complexity and cost. The present investigation is concerned with a novel form of antenna permitting high scan rates, taking into account a parabolic torus transreflector antenna. The feed horn illuminates one side of the radome with polarization parallel to the wires, which therefore reflect the radiation like a dish antenna. In the antenna considered, rotation of the beam is effected by mechanical rotation of the horn feed only, and this provides the potential for high scanning rates.

  5. FASTRACK (TM): Parabolic and Suborbital Experiment Support Facility

    NASA Technical Reports Server (NTRS)

    Richards, Stephanie E. (Compiler); Levine, Howard G.; Romero, V.

    2016-01-01

    FASTRACK was developed by NASA Kennedy Space Center and Space Florida to provide capabilities to conduct frequent, affordable, and responsive flight opportunities for reduced gravity experiments, technology development, and hardware testing on suborbital vehicles and parabolic flights.

  6. Building a parabolic solar concentrator prototype

    NASA Astrophysics Data System (ADS)

    Escobar-Romero, J. F. M.; Montiel, S. Vázquez y.; Granados-Agustín, F.; Cruz-Martínez, V. M.; Rodríguez-Rivera, E.; Martínez-Yáñez, L.

    2011-01-01

    In order to not further degrade the environment, people have been seeking to replace non-renewable natural resources such as fossil fuels by developing technologies that are based on renewable resources. An example of these technologies is solar energy. In this paper, we show the building and test of a solar parabolic concentrator as a prototype for the production of steam that can be coupled to a turbine to generate electricity or a steam engine in any particular industrial process.

  7. Effect of government policy on alternate-energy-technology market penetration

    SciTech Connect

    Mitchiner, J.L.

    1983-01-01

    Federal support for alternate energy technologies has gone through a boom/bust cycle during the Carter and Reagan administrations. To investigate the effects of these policies, I use a system dynamics model of the industrial market penetration of parabolic troughs as a case study. The Reagan policy, a laissez-faire policy, lets free-market forces determine the market penetration. The Carter policy, an active government policy, combines research, development and demonstration with information dissemination and market financial incentives. The optimal policy depends upon future energy prices. If the price of conventional energy remains low, parabolic troughs never become competitive even with significant government support and thus the laissez-faire policy reduces federal expenditures by approx. $60 million with no negative effects. If the price of unconventional energy increases significantly, however, free-market forces do not develop parabolic troughs into a practical energy source without the benefit of an active government program. If this case study is generalizable to other alternate energy technologies, an active government role in alternate energy technology development should be thought as an insurance policy. How much is it worth to the US today to insure future energy price stability.

  8. Gullied Trough Wall

    NASA Technical Reports Server (NTRS)

    2004-01-01

    13 June 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies emergent from beneath erosion-resistant rock layers in a trough south of Atlantis Chaos near 38.9oS, 176.3oW. Gullies such as these are fairly common in depressions at south middle latitudes. Tens of thousands of gullies have been identified in MGS MOC and Mars Odyssey Thermal Emission Imaging System (THEMIS) images. Whether they formed by running liquid water remains a controversial issue. Banked channels, like some shown here, are one form of evidence cited to indicate that a fluid with the properties of liquid water may have been involved. This image covers an area about 3 km (1.9 mi) across. The scene is illuminated by sunlight from the upper left.

  9. Proceedings of the Fifth Parabolic Dish Solar Thermal Power Program

    NASA Technical Reports Server (NTRS)

    Lucas, J. W. (Editor)

    1984-01-01

    The proceedings of the Fifth Parabolic Dish Solar Thermal Power Program Annual Review are presented. The results of activities within the Parabolic Dish Technology and Module/Systems Development element of the Department of Energy's Solar Thermal Energy Systems Program were emphasized. Among the topics discussed were: overall Project and Program aspects, Stirling and Brayton module development, concentrator and engine/receiver development along with associated hardware and test results; distributed systems operating experience; international parabolic dish development activities; and non-DOE-sponsored domestic dish activities. Solar electric generation was also addressed.

  10. Parabolic dish module experiment

    NASA Astrophysics Data System (ADS)

    1986-03-01

    A development test model of the 8-meter Solar Brayton Parabolic Dish Module has been designed, fabricated, and tested. The test model consists of five major subsystems: Sanders ceramic honeycomb solar receiver; LaJet LEC460 solar concentrator; AiRsearch SABC MKIIIA engine, Abacus 8 kW ac inverter; and a Sanders designed and built system controller. Goals of the tests were to integrate subsystem components into a working module, demonstrate the concept, and generate 5 kWe (hybrid) and 4.7 kWe (solar only) input. All subsystem integration goals were successfully achieved, but system performance efficiency was lower than expected. Contributing causes of the lower performance efficiencies have been identified. Modifications needed to restore performance to the required levels and improve the system life cycle cost have been addressed and are the subject of this final report.

  11. Structure of the Mekong trough

    SciTech Connect

    Van Khy, L.

    1986-01-01

    The Mekong trough occupies the shelf of southern Vietnam between the sea coast and the Condao-Cu Lao Tu line of islands and the adjacent area of the onshore Mekong delta. It extends for 400 km from southwest to northeast with a width of 100 km. The Mekong trough is situated on the upper Mesozoic volcanic belt of South Vietnam, which is part of the East Asian volcanogenic belt. It is bounded on the southeast by the Con Son high, on the southwest by the Corat-Ca Mau high, and on the northwest by the Dalat massif. The Mekong trough is considered to have major potential as a new petroleum province. Since 1969, numerous common depth point (CDP) seismic profiles have been run and seven deep wells have been drilled on the shelf in the Mekong trough. This paper is devoted to an analysis of the findings. 9 references, 4 figures.

  12. Mechatronic Prototype of Parabolic Solar Tracker.

    PubMed

    Morón, Carlos; Díaz, Jorge Pablo; Ferrández, Daniel; Ramos, Mari Paz

    2016-01-01

    In the last 30 years numerous attempts have been made to improve the efficiency of the parabolic collectors in the electric power production, although most of the studies have focused on the industrial production of thermoelectric power. This research focuses on the application of this concentrating solar thermal power in the unexplored field of building construction. To that end, a mechatronic prototype of a hybrid paraboloidal and cylindrical-parabolic tracker based on the Arduido technology has been designed. The prototype is able to measure meteorological data autonomously in order to quantify the energy potential of any location. In this way, it is possible to reliably model real commercial equipment behavior before its deployment in buildings and single family houses. PMID:27314359

  13. Mechatronic Prototype of Parabolic Solar Tracker

    PubMed Central

    Morón, Carlos; Díaz, Jorge Pablo; Ferrández, Daniel; Ramos, Mari Paz

    2016-01-01

    In the last 30 years numerous attempts have been made to improve the efficiency of the parabolic collectors in the electric power production, although most of the studies have focused on the industrial production of thermoelectric power. This research focuses on the application of this concentrating solar thermal power in the unexplored field of building construction. To that end, a mechatronic prototype of a hybrid paraboloidal and cylindrical-parabolic tracker based on the Arduido technology has been designed. The prototype is able to measure meteorological data autonomously in order to quantify the energy potential of any location. In this way, it is possible to reliably model real commercial equipment behavior before its deployment in buildings and single family houses. PMID:27314359

  14. Parabolic solar concentrator

    NASA Astrophysics Data System (ADS)

    Tecpoyotl-Torres, M.; Campos-Alvarez, J.; Tellez-Alanis, F.; Sánchez-Mondragón, J.

    2006-08-01

    In this work we present the basis of the solar concentrator design, which has is located at Temixco, Morelos, Mexico. For this purpose, this place is ideal due to its geographic and climatic conditions, and in addition, because it accounts with the greatest constant illumination in Mexico. For the construction of the concentrator we use a recycled parabolic plate of a telecommunications satellite dish (NEC). This plate was totally covered with Aluminum. The opening diameter is of 332 cm, the focal length is of 83 cm and the opening angle is of 90°. The geometry of the plate guaranties that the incident beams, will be collected at the focus. The mechanical treatment of the plate produces an average reflectance of 75% in the visible region of the solar spectrum, and of 92% for wavelengths up to 3μm in the infrared region. We obtain up to 2000°C of temperature concentration with this setup. The reflectance can be greatly improved, but did not consider it as typical practical use. The energy obtained can be applied to conditions that require of those high calorific energies. In order to optimize the operation of the concentrator we use a control circuit designed to track the apparent sun position.

  15. Parabolic aircraft solidification experiments

    NASA Technical Reports Server (NTRS)

    Workman, Gary L. (Principal Investigator); Smith, Guy A.; OBrien, Susan

    1996-01-01

    A number of solidification experiments have been utilized throughout the Materials Processing in Space Program to provide an experimental environment which minimizes variables in solidification experiments. Two techniques of interest are directional solidification and isothermal casting. Because of the wide-spread use of these experimental techniques in space-based research, several MSAD experiments have been manifested for space flight. In addition to the microstructural analysis for interpretation of the experimental results from previous work with parabolic flights, it has become apparent that a better understanding of the phenomena occurring during solidification can be better understood if direct visualization of the solidification interface were possible. Our university has performed in several experimental studies such as this in recent years. The most recent was in visualizing the effect of convective flow phenomena on the KC-135 and prior to that were several successive contracts to perform directional solidification and isothermal casting experiments on the KC-135. Included in this work was the modification and utilization of the Convective Flow Analyzer (CFA), the Aircraft Isothermal Casting Furnace (ICF), and the Three-Zone Directional Solidification Furnace. These studies have contributed heavily to the mission of the Microgravity Science and Applications' Materials Science Program.

  16. Energy and environment. A Sandia technology bulletin

    SciTech Connect

    Parrott, L.; Floyd, H.L.; Goetsch, B.; Doran, L.

    1993-03-01

    This bulletin discusses the following: decontamination of polluted water by using a photocatalyst to convert ultraviolet energy into electrochemical energy capable of destroying organic waste and removing toxic metals; monitoring oil spills with SAR by collecting data in digital form, processing the data, and creating digital images that are recorded for post-mission viewing and processing; revitalization of a solar industrial process heat system which uses parabolic troughs to heat water for foil production of integrated circuits; and an electronic information system, EnviroTRADE (Environmental Technologies for Remedial Actions Data Exchange) for worldwide exchange of environmental restoration and waste management information.

  17. Neotectonics of the Manych Trough

    NASA Astrophysics Data System (ADS)

    Makshaev, R. R.; Svitoch, A. A.

    2012-04-01

    Regional and local neotectonic features of the Manych Trough and regulating role of its tresholds in Caspian water overflows to the Black Sea are examined. Various evidence for neotectonic activity, with the maximums in Early and Late Khazarian epochs, of all the local tectonic rises in the Manych Trough, which were thresholds during the existence of the strait in the past, has been found. The Manych Trough is superimposed on the deep-laid faults of the Scythian Plate and in the sublatitudinal direction, it extends by more than 500 km. Throughout the Cenozoic, the system of narrow longitudinal and transverse structures continued to develop along the faults and some portions of these structures suffered differentiated motions in the Pleistocene as well. The general regional neotectonic Pleistocene character of the Manych Trough is confidently identified on the basis of coincidence with the large trough, which had been developing during Meso-Cenozoic; the non-altered character of modern relief; and the stable paleogeographic regime throughout the Pleistocene, when the Caspian straits repeatedly existed in the lowland parts of the trough. All these facts unambiguously indicate a general downward tectonic regime of the Manych Trough during the Pleistocene up to 100 m in amplitude. The amplitude of neotectonic motions of the trough over long time periods and within the Pleistocene in general were determined by comparative analysis of the modern and initial positions of reference horizons of the marine Pleistocene in the Manych Trough. The subsequent step-by-step comparison between the hypsometry of the bottom positions of the initial straits and the modern level of the corresponding strata allowed us to specify the value of tectonic deformation of the bottom for any concrete time period. The structural differentiation of the trough is clearly expressed in its modern relief and configuration of the river network; the former is en echelon sublatitudinal depressions joined

  18. Weak lensing by galaxy troughs

    NASA Astrophysics Data System (ADS)

    Gruen, Daniel

    2016-06-01

    Galaxy troughs, i.e. underdensities in the projected galaxy field, are a weak lensing probe of the low density Universe with high signal-to-noise ratio. I present measurements of the radial distortion of background galaxy images and the de-magnification of the CMB by troughs constructed from Dark Energy Survey and Sloan Digital Sky Survey galaxy catalogs. With high statistical significance and a relatively robust modeling, these probe gravity in regimes of density and scale difficult to access for conventional statistics.

  19. Parabolized stability equations

    NASA Astrophysics Data System (ADS)

    Herbert, Thorwald

    1994-04-01

    The parabolized stability equations (PSE) are a new approach to analyze the streamwise evolution of single or interacting Fourier modes in weakly nonparallel flows such as boundary layers. The concept rests on the decomposition of every mode into a slowly varying amplitude function and a wave function with slowly varying wave number. The neglect of the small second derivatives of the slowly varying functions with respect to the streamwise variable leads to an initial boundary-value problem that can be solved by numerical marching procedures. The PSE approach is valid in convectively unstable flows. The equations for a single mode are closely related to those of the traditional eigenvalue problems for linear stability analysis. However, the PSE approach does not exploit the homogeneity of the problem and, therefore, can be utilized to analyze forced modes and the nonlinear growth and interaction of an initial disturbance field. In contrast to the traditional patching of local solutions, the PSE provide the spatial evolution of modes with proper account for their history. The PSE approach allows studies of secondary instabilities without the constraints of the Floquet analysis and reproduces the established experimental, theoretical, and computational benchmark results on transition up to the breakdown stage. The method matches or exceeds the demonstrated capabilities of current spatial Navier-Stokes solvers at a small fraction of their computational cost. Recent applications include studies on localized or distributed receptivity and prediction of transition in model environments for realistic engineering problems. This report describes the basis, intricacies, and some applications of the PSE methodology.

  20. A novel portable device to measure the temperature of both the inner and the outer tubes of a parabolic receiver in the field

    NASA Astrophysics Data System (ADS)

    Hermoso, J. L. Navarro; Espinosa-Rueda, Guillermo; Martinez, Noelia; Heras, Carlos; Osta, Marta

    2016-05-01

    The performance of parabolic trough (PT) receiver tubes (RT) has a direct impact on Solar Thermal Energy (STE) plant production. As a result, one major need of operation and maintenance (O&M) in STE plants is to monitor the state of the receiver tube as a key element in the solar field. However the lack of specific devices so far has limited the proper evaluation of operating receiver tubés thermal performance. As a consequence non-accurate approximations have been accepted until now using infrared thermal images of the glass outer tube. In order to fulfill this need, Abengoa has developed a unique portable device for evaluating the thermal performance and vacuum state of parabolic trough receiver tubes placed in the field. The novel device described in this paper, simultaneously provides the temperature of both the inner steel tube and the outer glass tube enabling a check on manufacturers specifications. The on-field evaluation of any receiver tube at any operating temperature has become possible thanks to this new measuring device. The features and usability of this new measurement system as a workable portable device in operating solar fields provide a very useful tool for all companies in the sector contributing to technology progress. The originality of the device, patent pending P201431969, is not limited to the CSP sector, also having scientific significance in the general measuring instruments field. This paper presents the work carried out to develop and validate the device, also detailing its functioning properties and including the excellent results obtained in the laboratory to determine its accuracy and standard deviation. This information was validated with data collected by O&M teams using this instrument in a commercial CSP plant. The relevance of the device has been evidenced by evaluating a wide sample of RT and the results are discussed in this paper. Finally, all the on field collected data is used to demonstrate the high impact that using

  1. The Tricky Tear Trough

    PubMed Central

    Belden, Sarah; Miller, Richard A.

    2015-01-01

    There is a growing demand for noninvasive anti-aging products for which the periorbital region serves as a critical aspect of facial rejuvenation. This article reviews a multitude of cosmeceutical ingredients that have good scientific data, specifically for the periorbital region. Topical treatment options have exponentially grown from extensively studied retinoids, to recently developed technology, such as growth factors and peptides. With a focus on the periorbital anatomy, the authors review the mechanisms of action of topical cosmeceutical ingredients, effectiveness of ingredient penetration through the stratum corneum, and validity of clinical trials. PMID:26430490

  2. Utility-Scale Concentrating Solar Power and Photovoltaic Projects: A Technology and Market Overview

    SciTech Connect

    Mendelsohn, M.; Lowder, T.; Canavan, B.

    2012-04-01

    Over the last several years, solar energy technologies have been, or are in the process of being, deployed at unprecedented levels. A critical recent development, resulting from the massive scale of projects in progress or recently completed, is having the power sold directly to electric utilities. Such 'utility-scale' systems offer the opportunity to deploy solar technologies far faster than the traditional 'behind-the-meter' projects designed to offset retail load. Moreover, these systems have employed significant economies of scale during construction and operation, attracting financial capital, which in turn can reduce the delivered cost of power. This report is a summary of the current U.S. utility-scale solar state-of-the-market and development pipeline. Utility-scale solar energy systems are generally categorized as one of two basic designs: concentrating solar power (CSP) and photovoltaic (PV). CSP systems can be further delineated into four commercially available technologies: parabolic trough, central receiver (CR), parabolic dish, and linear Fresnel reflector. CSP systems can also be categorized as hybrid, which combine a solar-based system (generally parabolic trough, CR, or linear Fresnel) and a fossil fuel energy system to produce electric power or steam.

  3. Shenandoah parabolic dish solar collector

    SciTech Connect

    Kinoshita, G.S.

    1985-01-01

    The objectives of the Shenandoah, Georgia, Solar Total Energy System are to design, construct, test, and operate a solar energy system to obtain experience with large-scale hardware systems for future applications. This report describes the initial design and testing activities conducted to select and develop a collector that would serve the need of such a solar total energy system. The parabolic dish was selected as the collector most likely to maximize energy collection as required by this specific site. The fabrication, testing, and installation of the parabolic dish collector incorporating improvements identified during the development testing phase are described.

  4. Composite isogrid structures for parabolic surfaces

    NASA Technical Reports Server (NTRS)

    Silverman, Edward M. (Inventor); Boyd, Jr., William E. (Inventor); Rhodes, Marvin D. (Inventor); Dyer, Jack E. (Inventor)

    2000-01-01

    The invention relates to high stiffness parabolic structures utilizing integral reinforced grids. The parabolic structures implement the use of isogrid structures which incorporate unique and efficient orthotropic patterns for efficient stiffness and structural stability.

  5. Ridges and Troughs in Sippar Sulcus, Ganymede

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Embayment of ridges and troughs in a portion of the Sippar Sulcus area of Jupiter's moon Ganymede in this image from NASA's Galileo spacecraft is interpreted as evidence that the low-lying area was filled in by flooding with low-viscosity material, such as water or water-ice slush lavas. Bays of the material appeared to have formed in troughs (indicated by arrows) between the ridges.

    The smallest features visible are about 180 meters (590 feet) across. Analysis of such high-resolution images in combination with estimates of the features' relative elevations is helping scientists interpret the roles of volcanism and tectonics in creating the bright terrain on Ganymede.

    This image was prepared by the Lunar and Planetary Institute, Houston, and included in a report by Dr. Paul Schenk et al. in the March 1, 2001, edition of the journal Nature.

    The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C.

    Images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo .

  6. JPL's parabolic dish test site

    NASA Technical Reports Server (NTRS)

    Hagen, T. L.

    1980-01-01

    A parabolic dish test site (PDTS) was established in the California Mojave Desert to carry out work in testing solar point focusing concentrator systems and related hardware. The site was chosen because of its high solar insolation level and year around clear sky conditions. The various facilities and equipment at the PDTS, and the concentrator experiments being performed are described.

  7. Parabolic tapers for overmoded waveguides

    DOEpatents

    Doane, J.L.

    1983-11-25

    A waveguide taper with a parabolic profile, in which the distance along the taper axis varies as the square of the tapered dimension, provides less mode conversion than equal length linear tapers and is easier to fabricate than other non-linear tapers.

  8. Parabolic Dish Solar Thermal Power Annual Program Review Proceedings

    NASA Technical Reports Server (NTRS)

    Lucas, J. W.

    1982-01-01

    The results of activities of the parabolic dish technology and applications development element of DOE's Solar Thermal Energy System Program are presented. Topics include the development and testing of concentrators, receivers, and power conversion units; system design and development for engineering experiments; economic analysis and marketing assessment; and advanced development activities. A panel discussion concerning industrial support sector requirements is also documented.

  9. An Application of Calculus: Optimum Parabolic Path Problem

    ERIC Educational Resources Information Center

    Atasever, Merve; Pakdemirli, Mehmet; Yurtsever, Hasan Ali

    2009-01-01

    A practical and technological application of calculus problem is posed to motivate freshman students or junior high school students. A variable coefficient of friction is used in modelling air friction. The case in which the coefficient of friction is a decreasing function of altitude is considered. The optimum parabolic path for a flying object…

  10. Proceedings: Fourth Parabolic Dish Solar Thermal Power Program Review

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The results of activities within the parabolic dish technology and applications development program are presented. Stirling, organic Rankine and Brayton module technologies, associated hardware and test results to date; concentrator development and progress; economic analyses; and international dish development activities are covered. Two panel discussions, concerning industry issues affecting solar thermal dish development and dish technology from a utility/user perspective, are also included.

  11. Antireflection pyrex envelopes for parabolic solar collectors

    SciTech Connect

    McCollister, H.L.; Pettit, R.B.

    1983-01-01

    Parabolic trough solar collectors utilize glass envelopes around the receiver tube in order to reduce thermal losses. Antireflective (AR) coatings applied to the envelope can potentially increase the solar transmittance by 0.07. An excellent AR surface can be formed on Pyrex (Corning Code 7740 glass) by first heat treating the glass to cause a compositional phase separation. After heat treating, a surface layer is removed using a pre-etch solution of aqueous ammonium bifluoride. Finally the AR layer is formed by etching in a solution containing hydrofluorosilic and ammonium bifluoride acid. Processing parameters studied included the phase separation temperature and heat treatment time, the pre-etch time, and the etching bath temperature and time. AR-coated samples with solar transmittance values >0.97, as compared to a value of 0.91 in untreated samples, were obtained for a range of heat treatment temperatures from 560 to 630/sup 0/C. The phase separation time and temperature interact so that at 630/sup 0/C short times are required (3 hours) while at 560/sup 0/C longer times are necessary (24 hours). Optimum values for the other processing parameters are 12 to 18 minutes in the pre-etching bath, and 5 to 10 minutes in the film forming bath when maintained between 35 and 45/sup 0/C. Application of this process to full scale 3 m long x 6 cm diameter Pyrex envelopes was successful in producing solar transmittance values greater than or equal to 0.97.

  12. Antireflection Pyrex envelopes for parabolic solar collectors

    SciTech Connect

    McCollister, H.L.; Pettit, R.B.

    1983-11-01

    Parabolic trough solar collectors utilize glass envelopes around the receiver tube in order to reduce thermal losses. Antireflective (AR) coatings applied to the envelope can potentially increase the solar transmittance by 7 percent. An excellent AR surface can be formed on Pyrex (Corning Code 7740 glass) by first heat treating the glass to cause a compositional phase separation. After heat treating, a surface layer is removed using a pre-etch solution of aqueous ammonium bifluoride. Finally, the AR layer is formed by etching in a solution containing hydrofluorosilic and ammonium bifluoride acid. Processing parameters studied included the phase separation temperature and heat treatment time, the pre-etch time, and the etching bath temperature and time. AR-coated samples with solar transmittance values > 0.97, as compared to a value of 0.91 in untreated samples, were obtained for a range of heat treatment temperatures from 560-630/sup 0/C. The phase separation time and temperature interact so that at 630/sup 0/C short times are required (3 hrs) while at 560/sup 0/C longer times are necessary (24 hrs). Optimum values for the other processing parameters are 12-18 min in the pre-etching bath, and 5-10 min in the film forming bath when maintained between 35-45/sup 0/C. Application of this process to full scale 3-m-long X 6-cm dia Pyrex envelopes was successful in producing solar transmittance values greater than or equal to 0.97.

  13. Renewable energy technologies for federal facilities: Solar water heating

    SciTech Connect

    1996-05-01

    This sheet presents information on solar water heaters (passive and active), solar collectors (flat plate, evacuated tube, parabolic trough), lists opportunities for use of solar water heating, and describes what is required and the costs. Important terms are defined.

  14. Advanced photovoltaic-trough development

    SciTech Connect

    Spencer, R.; Yasuda, K.; Merson, B.

    1982-04-01

    The scope of the work on photvoltaic troughs includes analytical studies, hardware development, and component testing. Various aspects of the system have been optimized and improvements have been realized, particularly in the receiver and reflecting surface designs. An empirical system performance model has been developed that closely agrees with measured system performance. This in-depth study of single-axis reflecting linear focus photovoltaic concentrators will be very beneficial in the development of improved models for similar systems as well as other phtovoltaic concentrator designs.

  15. Fabrication of trough-shaped solar collectors

    DOEpatents

    Schertz, William W.

    1978-01-01

    There is provided a radiant energy concentration and collection device formed of a one-piece thin-walled plastic substrate including a plurality of nonimaging troughs with certain metallized surfaces of the substrate serving as reflective side walls for each trough. The one-piece plastic substrate is provided with a seating surface at the bottom of each trough which conforms to the shape of an energy receiver to be seated therein.

  16. Acceptance Performance Test Guideline for Utility Scale Parabolic Trough and Other CSP Solar Thermal Systems: Preprint

    SciTech Connect

    Mehos, M. S.; Wagner, M. J.; Kearney, D. W.

    2011-08-01

    Prior to commercial operation, large solar systems in utility-size power plants need to pass a performance acceptance test conducted by the engineering, procurement, and construction (EPC) contractor or owners. In lieu of the present absence of ASME or other international test codes developed for this purpose, the National Renewable Energy Laboratory has undertaken the development of interim guidelines to provide recommendations for test procedures that can yield results of a high level of accuracy consistent with good engineering knowledge and practice. Progress on interim guidelines was presented at SolarPACES 2010. Significant additions and modifications were made to the guidelines since that time, resulting in a final report published by NREL in April 2011. This paper summarizes those changes, which emphasize criteria for assuring thermal equilibrium and steady state conditions within the solar field.

  17. 241-AZ-101 pump removal trough analysis

    SciTech Connect

    Coverdell, B.L.

    1995-10-17

    As part of the current Hanford mission of environmental cleanup, various long length equipment must be removed from highly radioactive waste tanks. The removal of equipment will utilize portions of the Equipment Removal System for Project W320 (ERS-W320), specifically the 50 ton hydraulic trailer system. Because the ERS-W320 system was designed to accommodate much heavier equipment it is adequate to support the dead weight of the trough, carriage and related equipment for 241AZ101 pump removal project. However, the ERS-W320 components when combined with the trough and its` related components must also be analyzed for overturning due to wind loads. Two troughs were designed, one for the 20 in. diameter carriage and one for the 36 in. diameter carriage. A proposed 52 in. trough was not designed and, therefore is not included in this document. In order to fit in the ERS-W320 strongback the troughs were design with the same widths. Structurally, the only difference between the two troughs is that more material was removed from the stiffener plates on the 36 in trough. The reduction in stiffener plate material reduces the allowable load. Therefore, only the 36 in. trough was analyzed.

  18. Parabolic curves in Lie groups

    SciTech Connect

    Pauley, Michael

    2010-05-15

    To interpolate a sequence of points in Euclidean space, parabolic splines can be used. These are curves which are piecewise quadratic. To interpolate between points in a (semi-)Riemannian manifold, we could look for curves such that the second covariant derivative of the velocity is zero. We call such curves Jupp and Kent quadratics or JK-quadratics because they are a special case of the cubic curves advocated by Jupp and Kent. When the manifold is a Lie group with bi-invariant metric, we can relate JK-quadratics to null Lie quadratics which arise from another interpolation problem. We solve JK-quadratics in the Lie groups SO(3) and SO(1,2) and in the sphere and hyperbolic plane, by relating them to the differential equation for a quantum harmonic oscillator00.

  19. Parabolic dish photovoltaic concentrator development

    NASA Astrophysics Data System (ADS)

    Beninga, K.; Davenport, R.; Featherby, M.; Sandubrae, J.; Walcott, K.

    1991-05-01

    Science Applications International Corporation (SAIC) and Tactical Fabs, Inc. (TFI) have fabricated a prototype parabolic dish photovoltaic (PV) concentrator system to demonstrate the functionality of this approach. A 1.5 m diameter parabolic dish was fabricated of a polyester/fiberglass composite, with a silvered polymer reflective surface. An innovative receiver cooling system used outward radial flow of cooling water in a narrow passage. This configuration matches the heat transfer capability of the cooling system to the flux profile on the PV receiver, minimizing temperature variations across the receiver. The photovoltaic cells used in the system were a new, TFI-proprietary design. Interleaved contacts form a bi-polar, rear-contact cell configuration. Because the electrical contacts are made on the rear of the cells, cells can be close-packed to form receiver arrays of arbitrary shape and size. Optical testing of the dish concentrator was performed by SAIC, SERI, and Sandia National Labs. The dish concentrator, designed for solar thermal applications, had a tight focal spot but exhibited flux non-uniformities away from the focal plane. Thermal testing of the receiver cooling system was performed with excellent success. Single PV cells, 4-cell blocks, and 144-cell receiver modules were built and tested. The cells successfully demonstrated the TFI design concept, but due to cell processing problems their efficiency was very low. Sources of the processing problems were identified and solutions were proposed, but funding limitations precluded further cell production. Operation of the complete PV dish system was conducted, and the functionality of the system was demonstrated. However, low cell efficiencies and receiver plane flux non-uniformities caused the system performance to be very low. These problems are not generic to the concept, and solutions to them proposed.

  20. Trough Receiver Heat Loss Testing (Presentation)

    SciTech Connect

    Lewandowski, A.; Feik, C.; Hansen, R.; Phillips, S.; Bingham, C.; Netter, J.; Forristal, R.; Burkholder, F.; Meglan, B.; Wolfrum, E.

    2006-02-01

    This presentation describes the design, fabrication, and qualification of an experimental capability for thermal loss testing of full-size trough receiver elements; and the testing on a variety of receivers.

  1. Preliminary definition and characterization of a solar industrial process heat technology and manufacturing plant for the year 2000

    SciTech Connect

    Prythero, T.; Meyer, R. T.

    1980-09-01

    A solar industrial process heat technology and an associated solar systems manufacturing plant for the year 2000 has been projected, defined, and qualitatively characterized. The technology has been defined for process heat applications requiring temperatures of 300/sup 0/C or lower, with emphasis on the 150/sup 0/ to 300/sup 0/C range. The selected solar collector technology is a parabolic trough collector of the line-focusing class. The design, structure, and material components are based upon existing and anticipated future technological developments in the solar industry. The solar system to be manufactured and assembled within a dedicated manufacturing plant is projected to consist of the collector and the major collector components, including reflector, absorber, parabolic trough structure, support stand, tracking drive mechanism, sun-sensing device and control system, couplings, etc. Major manufacturing processes to be introduced into the year 2000 plant operations are glassmaking, silvering, electroplating and plastic-forming. These operations will generate significant environmental residuals not encountered in present-day solar manufacturing plants. Important residuals include chemical vapors, acids, toxic elements (e.g. arsenic), metallic and chemical sludges, fumes from plastics, etc. The location, design, and operations of these sophisticated solar manufacturing plants will have to provide for the management of the environmental residuals.

  2. Analysis of the Quality of Parabolic Flight

    NASA Technical Reports Server (NTRS)

    Lambot, Thomas; Ord, Stephan F.

    2016-01-01

    Parabolic flights allow researchers to conduct several 20 second micro-gravity experiments in the course of a single day. However, the measurement can have large variations over the course of a single parabola, requiring the knowledge of the actual flight environment as a function of time. The NASA Flight Opportunities program (FO) reviewed the acceleration data of over 400 parabolic flights and investigated the quality of micro-gravity for scientific purposes. It was discovered that a parabolic flight can be segmented into multiple parts of different quality and duration, a fact to be aware of when planning an experiment.

  3. Phase retrieval in situ measurement for large aperture parabolic mirror

    NASA Astrophysics Data System (ADS)

    Ding, Lingyan; Wu, Yulie; Li, Shengyi; Liao, Yang; Shu, Yong

    2010-10-01

    Phase retrieval is a promising method for in-situ metrology and has been applied to spherical mirror surface metrology successfully. To meet the requirement of in-situ measurement in manufacturing large aperture parabolic mirror, a new method using phase retrieval technology is developed. In this method, an approximately parallel beam is used to illuminate the large parabolic mirror. The beam is produced by a point light source far away from the tested mirror. Then, intensity of diffraction patterns near the focus is measured by CCD. The experiment of testing a parabolic mirror with aperture 400mm and radius of curvature at vertex 2789.7mm is described. And some advices of improving the setup are presented. Errors brought by the approximately parallel beam are compensated by an algorithm derived from GS iterative algorithm. Phase retrieval result is consistent with that measured by interferometer sub-aperture stitching in error distribution, PV value and RMS value. The experiment shows that this method features simple optical path, good anti-vibration ability and acceptable accuracy.

  4. How do spiral troughs form on Mars?

    NASA Astrophysics Data System (ADS)

    Pelletier, Jon D.

    2004-04-01

    A three-dimensional model for the coupled evolution of ice-surface temperature and elevation in the Martian polar ice caps is presented. The model includes (1) enhanced heat absorption on steep, dust-exposed scarps, (2) accumulation and ablation, and (3) lateral conduction of heat within the ice cap. The model equations are similar to classic equations for excitable media, including nerve fibers and chemical oscillators. In two dimensions, a small zone of initial melting in the model develops into a train of poleward-migrating troughs with widths similar to those observed on Mars. Starting from random initial conditions, the three-dimensional model reproduces spiral waves very similar to those in the north polar ice cap, including secondary features such as gull-wing shaped troughs, bifurcations, and terminations. These results suggest that eolian processes and ice flow may not control trough morphology.

  5. The integrated compound parabolic concentrator: From development to demonstration

    SciTech Connect

    Winston, R.; O`Gallagher, J.J.; Duff, W.S.; Cavallaro, A.

    1997-12-31

    The authors describe the fabrication, testing and application of the Integrated Compound Parabolic Concentrator (ICPC) to solar cooling. The cooling technology is a double effect absorption cycle chiller operating at 165 C. The design parameters are optimized for this temperature range. The optical and mechanical design of the solar collector is chosen for compatibility with mass production. A project to employ approximately 350 of these collector tubes to drive a 20 ton commercial double effect chiller on an office building in Sacramento, CA has started. The authors expect the system to be operational this year.

  6. Piecewise-Planar Parabolic Reflectarray Antenna

    NASA Technical Reports Server (NTRS)

    Hodges, Richard; Zawadzki, Mark

    2009-01-01

    The figure shows a dual-beam, dualpolarization Ku-band antenna, the reflector of which comprises an assembly of small reflectarrays arranged in a piecewise- planar approximation of a parabolic reflector surface. The specific antenna design is intended to satisfy requirements for a wide-swath spaceborne radar altimeter, but the general principle of piecewise-planar reflectarray approximation of a parabolic reflector also offers advantages for other applications in which there are requirements for wideswath antennas that can be stowed compactly and that perform equally in both horizontal and vertical polarizations. The main advantages of using flat (e.g., reflectarray) antenna surfaces instead of paraboloidal or parabolic surfaces is that the flat ones can be fabricated at lower cost and can be stowed and deployed more easily. Heretofore, reflectarray antennas have typically been designed to reside on single planar surfaces and to emulate the focusing properties of, variously, paraboloidal (dish) or parabolic antennas. In the present case, one approximates the nominal parabolic shape by concatenating several flat pieces, while still exploiting the principles of the planar reflectarray for each piece. Prior to the conception of the present design, the use of a single large reflectarray was considered, but then abandoned when it was found that the directional and gain properties of the antenna would be noticeably different for the horizontal and vertical polarizations.

  7. Tectonic evolution and volcanism of Okinawa Trough

    SciTech Connect

    Sibuet, J.C.; Letouzey, J.; Marsset, B.; Davagnier, M.; Foucher, J.P.; Bougault, H.; Dosso, L.; Maury, R.; Joron, J.L.

    1986-07-01

    The Okinawa Trough is a back-arc basin formed by extension of the east China continental lithosphere behind the Ryukyu Trench system. The age of marine deposits drilled in the northern Okinawa Trough indicates a Miocene age for the splitting of the volcanic arc and the first tensional movements. The POP 1 cruise of the R/V Jean-Charcot (September-October 1984) provided new evidence concerning the two main periods of extension as recognized by Kimura (Marine and Petroleum Geology, 1985). Tilted fault blocks in the northern Okinawa Trough trend north 40/sup 0/-60/sup 0/ and belong to the early Pleistocene phase (2-0.5 Ma). The present-day phase is characterized over the entire basin by normal faults oriented 80/sup 0/N in the north and 90/sup 0/N in the south. In the southern Okinawa Trough, most of the deformation occurs along linear, subparallel, en echelon depressions intruded by volcanic ridges associated with positive magnetic anomalies. The system of volcanic ridges ends northeast of Okinawa Island in a series of parallel volcanic ridges named the VAMP (Volcanic arc-rift migration processes) area, which merges into an active volcanic chain extending north to Japan. Chemical analyses of the vesicular basalts dredged on the back-arc basin display flat to enriched rare-earth patterns. The niobium-tantalum negative anomalies reflect a subduction signature. A good positive correlation between strontium isotopic compositions and concentrations suggests a contamination effect.

  8. Cooling-Trough Condenser for Sublimation Tubes

    NASA Astrophysics Data System (ADS)

    Eisenbraun, E. J.; Lucas, J. M.

    1995-11-01

    A wrap-around, trough condenser for use with large diameter (2.5") sublimation tubes is described. The design permits attachment of the condenser to the sublimation tube without removing the tube from the heater. It also permits the use of a variety of liquid (tap water, Dry Ice, and alcohol or acetone) or solid (ice or Dry Ice) coolants.

  9. Detail of pumps in troughs, detail of truss attachment ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of pumps in troughs, detail of truss - attachment to the wall - as well as the troughs themselves. Interior of the main hatchery building, view to the east. - Prairie Creek Fish Hatchery, Hwy. 101, Orick, Humboldt County, CA

  10. Revisiting trough interactions and tropical cyclone intensity change

    NASA Astrophysics Data System (ADS)

    Peirano, C. M.; Corbosiero, K. L.; Tang, B. H.

    2016-05-01

    An updated climatology of Atlantic basin tropical cyclone (TC) intensity change in the presence of upper tropospheric trough forcing is presented. To control for changes in the background thermodynamic environment, a methodology that normalizes intensity change by the potential intensity of the TC is used to more narrowly focus on the effect of troughs compared to previous studies. Relative to the full sample of Atlantic TCs, troughs are a negative influence on intensification: trough interaction cases are 4% less likely to intensify and 5% more likely to weaken. Troughs are especially detrimental compared to TCs without trough forcing: trough interaction cases are 14% less likely to intensify and 13% more likely to weaken. Additionally, eddy flux convergence of angular momentum, previously shown to positively affect TC intensity change, is shown to be a weak predictor of intensity change compared to vertical wind shear, which is enhanced during a trough interaction.

  11. Critical wind effects on parabolic reflectors

    NASA Astrophysics Data System (ADS)

    Campbell, Marvin F.

    2004-09-01

    For decades designers of dish antennas and radio telescopes have known the aerodynamic properties of parabolic reflectors. However, site planners and end users are not necessarily versed in their properties, and so can place them on sites or use them in such a manner that the wind causes a maximum of disruption of the pointing and tracking performance. Parabolic reflectors make excellent airfoils, and as such act like an airplane wing in many respects. Having some knowledge of sensitive wind directions relative to the Line Of Sight (LOS) can lead a user to change his site selection or operating procedures to achieve the optimum pointing and tracking performance for most observations. This knowledge can also contribute information to help specify the necessary performance characteristics. This paper discusses the aerodynamic properties of parabolic reflectors so the reader can get a ready grasp of the issues.

  12. Parabolic flight as a spaceflight analog.

    PubMed

    Shelhamer, Mark

    2016-06-15

    Ground-based analog facilities have had wide use in mimicking some of the features of spaceflight in a more-controlled and less-expensive manner. One such analog is parabolic flight, in which an aircraft flies repeated parabolic trajectories that provide short-duration periods of free fall (0 g) alternating with high-g pullout or recovery phases. Parabolic flight is unique in being able to provide true 0 g in a ground-based facility. Accordingly, it lends itself well to the investigation of specific areas of human spaceflight that can benefit from this capability, which predominantly includes neurovestibular effects, but also others such as human factors, locomotion, and medical procedures. Applications to research in artificial gravity and to effects likely to occur in upcoming commercial suborbital flights are also possible. PMID:26796759

  13. Controllable parabolic-cylinder optical rogue wave

    NASA Astrophysics Data System (ADS)

    Zhong, Wei-Ping; Chen, Lang; Belić, Milivoj; Petrović, Nikola

    2014-10-01

    We demonstrate controllable parabolic-cylinder optical rogue waves in certain inhomogeneous media. An analytical rogue wave solution of the generalized nonlinear Schrödinger equation with spatially modulated coefficients and an external potential in the form of modulated quadratic potential is obtained by the similarity transformation. Numerical simulations are performed for comparison with the analytical solutions and to confirm the stability of the rogue wave solution obtained. These optical rogue waves are built by the products of parabolic-cylinder functions and the basic rogue wave solution of the standard nonlinear Schrödinger equation. Such rogue waves may appear in different forms, as the hump and paw profiles.

  14. Holomorphic Parabolic Geometries and Calabi-Yau Manifolds

    NASA Astrophysics Data System (ADS)

    McKay, Benjamin

    2011-09-01

    We prove that the only complex parabolic geometries on Calabi-Yau manifolds are the homogeneous geometries on complex tori. We also classify the complex parabolic geometries on homogeneous compact Kähler manifolds.

  15. Discontinuous Mixed Covolume Methods for Parabolic Problems

    PubMed Central

    Zhu, Ailing

    2014-01-01

    We present the semidiscrete and the backward Euler fully discrete discontinuous mixed covolume schemes for parabolic problems on triangular meshes. We give the error analysis of the discontinuous mixed covolume schemes and obtain optimal order error estimates in discontinuous H(div) and first-order error estimate in L2. PMID:24983008

  16. Parabolic Dish Concentrator (PDC-2) Development

    NASA Technical Reports Server (NTRS)

    Rafinejad, D.

    1984-01-01

    The design of the Parabolic Dish Concentrator (PDC-2) is described. The following five subsystems of the concentrator are discussed: (1) reflective surface subsystem, (2) support structure subsystem, (3) foundation, (4) drive subsystem, and (5) electrical and control subsystem. The status of the PDC-2 development project is assessed.

  17. Distributed neural signals on parabolic cylindrical shells

    NASA Astrophysics Data System (ADS)

    Hu, S. D.; Li, H.; Tzou, H. S.

    2013-06-01

    Parabolic cylindrical shells are commonly used as key components in communication antennas, space telescopes, solar collectors, etc. This study focuses on distributed modal neural sensing signals on a flexible simply-supported parabolic cylindrical shell panel. The parabolic cylindrical shell is fully laminated with a piezoelectric layer on its outer surface and the piezoelectric layer is segmented into infinitesimal elements (neurons) to investigate the microscopic distributed neural sensing signals. Since the dominant vibration component of the shell is usually the transverse oscillation, a new transverse mode shape function is defined. Two shell cases, i.e., the ratio of the meridian height to the half span distance of a parabola at 1:4 (shallow) and 1:1 (deep), are studied to reveal the curvature effect to the neural sensing signals. Studies suggest that the membrane signal component dominates for lower natural modes and the bending signal component dominates for higher natural modes. The meridional membrane and bending signal components are mostly concentrated on the high-curvature areas, while the longitudinal bending component is mostly concentrated on the relatively flat areas. The concentration behavior becomes more prominent as the parabolic cylindrical shell deepens, primarily resulting from the enhanced membrane effect due to the increased curvature.

  18. The linear regulator problem for parabolic systems

    NASA Technical Reports Server (NTRS)

    Banks, H. T.; Kunisch, K.

    1983-01-01

    An approximation framework is presented for computation (in finite imensional spaces) of Riccati operators that can be guaranteed to converge to the Riccati operator in feedback controls for abstract evolution systems in a Hilbert space. It is shown how these results may be used in the linear optimal regulator problem for a large class of parabolic systems.

  19. Manufacture of large, lightweight parabolic antennas

    NASA Technical Reports Server (NTRS)

    Hooper, S. W.

    1973-01-01

    Antenna was produced in segments. Parabole sections were built up as aluminum foil sandwich with core bonded by film adhesive; whole structure was oven-cured after assembly. Structure was assembled with special tool for splice-bonding segments into complete dish, and inflatable bladder to apply pressure at joints during cure.

  20. Deformation and Seismicity Within the Salton Trough

    NASA Astrophysics Data System (ADS)

    Lohman, R. B.; McGuire, J. J.

    2005-12-01

    We examine ground deformation and seismicity within the Salton Trough of Southern California with Interferometric Synthetic Aperture Radar (InSAR). The Salton Trough is the landward extension of the spreading centers and transforms within the Gulf of California, and is associated with a higher heat flow than is found further north along the San Andreas system. The Salton Trough region is characterized by seismicity swarms similar to those that are characteristic of fault systems on the East Pacific Rise. Transient episodes of shallow and deep creep occur on the southern San Andreas, Imperial, and Superstition Hills faults, and pronounced afterslip and triggered slip are associated with local and regional earthquakes. Documentation of the temporal and spatial evolution of transient and triggered slip phenomena is vital to development of stress transfer and strain partitioning models explaining the dynamics of interactions within the North America-Pacific plate boundary. We determine the extent to which aseismic fault slip can be observed with SAR data, and perform specific investigations of the time periods surrounding several of the ~10 major earthquake swarms that have occurred within the Salton Trough since 1992. We seek to determine whether seismic swarm activity is associated with aseismic slip transients. Extensive agricultural activity in the region limits the utility of traditional InSAR, so we explore use of the persistent scatterer method to isolate roads, buildings and other features that retain interferometric coherence over time. Because a large number of SAR acquisitions are available (>30), and because of the large spatial and temporal variations in coherence between urban, agricultural, water-covered and desert landscapes within the scene, the Salton trough provides an interesting test scenario for the persistent scatterer method. We use spatially and temporally varying fault slip to model observed activity on the Superstition Hills fault. We explore

  1. Inflammation is associated with voriconazole trough concentrations.

    PubMed

    van Wanrooy, Marjolijn J P; Span, Lambert F R; Rodgers, Michael G G; van den Heuvel, Edwin R; Uges, Donald R A; van der Werf, Tjip S; Kosterink, Jos G W; Alffenaar, Jan-Willem C

    2014-12-01

    Voriconazole concentrations display a large variability, which cannot completely be explained by known factors. Inflammation may be a contributing factor, as inflammatory stimuli can change the activities and expression levels of cytochrome P450 isoenzymes. We explored the correlation between inflammation, reflected by C-reactive protein (CRP) concentrations, and voriconazole trough concentrations. A retrospective chart review of patients with at least one steady-state voriconazole trough concentration and a CRP concentration measured on the same day was performed. A total of 128 patients were included. A significantly (P < 0.001) higher voriconazole trough concentration was observed in patients with severe inflammation (6.2 mg/liter; interquartile range [IQR], 3.4 to 8.7 mg/liter; n = 20) than in patients with moderate inflammation (3.4 mg/liter; IQR, 1.6 to 5.4 mg/liter; n = 60) and in patients with no to mild inflammation (1.6 mg/liter; IQR, 0.8 to 3.0 mg/liter; n = 48). The patients in all three groups received similar voriconazole doses based on mg/kg body weight (P = 0.368). Linear regression analyses, both unadjusted and adjusted for covariates of gender, age, dose, route of administration, liver enzymes, and interacting coadministered medications, showed a significant association between voriconazole and CRP concentration (P < 0.001). For every 1-mg/liter increase in the CRP concentration, the voriconazole trough concentration increased by 0.015 mg/liter (unadjusted 95% confidence interval [CI], 0.011 to 0.020 mg/liter; adjusted 95% CI, 0.011 to 0.019 mg/liter). Inflammation, reflected by the C-reactive protein concentration, is associated with voriconazole trough concentrations. Further research is necessary to assess if taking the inflammatory status of a patient into account is helpful in therapeutic drug monitoring of voriconazole to maintain concentrations in the therapeutic window, thereby possibly preventing suboptimal treatment or adverse events

  2. Prolonging Microgravity on Parabolic Airplane Flights

    NASA Technical Reports Server (NTRS)

    Robinson, David W.

    2003-01-01

    Three techniques have been proposed to prolong the intervals of time available for microgravity experiments aboard airplanes flown along parabolic trajectories. Typically, a pilot strives to keep an airplane on such a trajectory during a nominal time interval as long as 25 seconds, and an experimental apparatus is released to float freely in the airplane cabin to take advantage of the microgravitational environment of the trajectory for as long as possible. It is usually not possible to maintain effective microgravity during the entire nominal time interval because random aerodynamic forces and fluctuations in pilot control inputs cause the airplane to deviate slightly from a perfect parabolic trajectory, such that the freely floating apparatus bumps into the ceiling, floor, or a wall of the airplane before the completion of the parabola.

  3. Nanofocusing Parabolic Refractive X-Ray Lenses

    SciTech Connect

    Schroer, C.G.; Kuhlmann, M.; Hunger, U.T.; Guenzler, T.F.; Kurapova, O.; Feste, S.; Lengeler, B.; Drakopoulos, M.; Somogyi, A.; Simionovici, A. S.; Snigirev, A.; Snigireva, I.

    2004-05-12

    Parabolic refractive x-ray lenses with short focal distance can generate intensive hard x-ray microbeams with lateral extensions in the 100nm range even at short distance from a synchrotron radiation source. We have fabricated planar parabolic lenses made of silicon that have a focal distance in the range of a few millimeters at hard x-ray energies. In a crossed geometry, two lenses were used to generate a microbeam with a lateral size of 330nm by 110nm at 25keV in a distance of 41.8m from the synchrotron radiation source. First microdiffraction and fluorescence microtomography experiments were carried out with these lenses. Using diamond as lens material, microbeams with lateral size down to 20nm and below are conceivable in the energy range from 10 to 100keV.

  4. New Parabolic Flight Platform for Microgravity Experiments

    NASA Astrophysics Data System (ADS)

    Valdatta, M.; Brucas, D.; Tomkus, V.; Ragauskas, U.; Razgunas, M.

    2015-09-01

    Microgravity experiments are important in field of space development; they give the possibility to simulate near-space conditions to test new kind of systems and subsystems for space or to perform biological researches. The existing platforms, to perform reduced gravity experiments, allow achieving the targets of the researches. Otherwise these platforms are either very expensive or of a very short duration. Another important issue is the repeatability of the experiment for some platforms. Fast repeatability platform (ensuring fast turnaround time), can guarantee only few seconds of microgravity time. For these reason there is the need of platforms for microgravity experiments that will cover the needs of all the experiments that cannot fit into required time, cost and repeatability of any other experiment methodology. The paper explains the mission plan and first scientific data of new family of parabolic unmanned planes. Each of these planes can be used to achieve scientific parabolic flight.

  5. Parabolic antennas with a loaded flange

    NASA Astrophysics Data System (ADS)

    Bucci, O. M.; Gennarelli, C.; Palumbo, L.

    1985-07-01

    The radiation characteristics of a parabolic dish with a loaded peripheral flange are examined in detail in order to assess the effectiveness of such a loading in further reducing the backward scattered field. Uniformly valid diffraction coefficients are developed to deal with both isotropic and anisotropic surface impedances. It is shown that substantial improvement of the antenna performance can be obtained in a wide rear angular sector, and the optimal loading conditions are determined.

  6. Simulation of parabolic reflectors for ultraviolet phototherapy.

    PubMed

    Robert Grimes, David

    2016-08-21

    Ultraviolet (UVR) phototherapy is widely used to treat an array of skin conditions, including psoriasis, eczema and vitiligo. For such interventions, a quantified dose is vital if the treatment is to be both biologically effective and to avoid the detrimental effects of over-dosing. As dose is absorbed at surface level, the orientation of patient site with respect to the UVR lamps modulates effective dose. Previous investigations have modelled this behaviour, and examined the impact of shaped anodized aluminium reflectors typically placed around lamps in phototherapy cabins. These mirrors are effective but tend to yield complex patterns of reflection around the cabin which can result in substantial dose inhomogeneity. There has been some speculation over whether using the reflective property of parabolic mirrors might improve dose delivery or homogeneity through the treatment cabin. In this work, the effects of parabolic mirrors are simulated and compared with standard shaped mirrors. Simulation results strongly suggest that parabolic reflectors reduce total irradiance relative to standard shaped reflectors, and have a negligible impact on dose homogeneity. PMID:27445095

  7. Simulation of parabolic reflectors for ultraviolet phototherapy

    NASA Astrophysics Data System (ADS)

    Grimes, David Robert

    2016-08-01

    Ultraviolet (UVR) phototherapy is widely used to treat an array of skin conditions, including psoriasis, eczema and vitiligo. For such interventions, a quantified dose is vital if the treatment is to be both biologically effective and to avoid the detrimental effects of over-dosing. As dose is absorbed at surface level, the orientation of patient site with respect to the UVR lamps modulates effective dose. Previous investigations have modelled this behaviour, and examined the impact of shaped anodized aluminium reflectors typically placed around lamps in phototherapy cabins. These mirrors are effective but tend to yield complex patterns of reflection around the cabin which can result in substantial dose inhomogeneity. There has been some speculation over whether using the reflective property of parabolic mirrors might improve dose delivery or homogeneity through the treatment cabin. In this work, the effects of parabolic mirrors are simulated and compared with standard shaped mirrors. Simulation results strongly suggest that parabolic reflectors reduce total irradiance relative to standard shaped reflectors, and have a negligible impact on dose homogeneity.

  8. Revisiting the Ariel Trough Work for HF Telecommunication Purposes

    NASA Astrophysics Data System (ADS)

    Tulunay, Y.; Stanisławska, I.; Rothkaehl, H.

    2003-07-01

    Muldrew [1] was the pioneer who reported the midlatitude electron density trough at the topside ionosphere. For about ten to fifteen years the trough, its morphology, dynamical behavior, relationship to the equatorial plasmapause, and physical and chemical processes which lead to the trough formation had been extensively investigated. Then, the work on the trough had been slowed down gradually. As the new space systems have become more vulnerable to space weather effects, a need for robust programs and a long track record in space environment sensing and modeling to produce new space environment models and products that would meet high-priority defense and commercial needs arises naturally. In this context, it is intended to go over the reported trough work dating back to the 1970s and some typical findings of later developments briefly. Most of the aspects of the trough studies have been repeated with new data for newer physical models. From this point of view, the Ariel 3 and Ariel 4 satellite trough results are chosen since the work on the Ariel trough had been very original and very extensive quantitatively and qualitatively in the 1970s. The results reviewed here are based on more than 1000 beautiful selected trough cases. Due to the good quality and quantity of the Ariel satellite data, equal coverage in space and time were maintained, which makes the trough results very important. This paper will end with some reference to the trough models, results that establish a link between the topside and the F2 region of the ionosphere. As one typical application, HF radiocommunication is chosen to be the point of interest. In practical applications of the HF radiocommunications any model that does not include the trough is not complete.

  9. The origin and evolution of the Cretaceous Benue Trough (Nigeria)

    NASA Astrophysics Data System (ADS)

    Benkhelil, J.

    The intracontinental Benue Trough was initiated during the Lower Cretaceous in relation with the Atlantic Ocean opening. The first stage of its evolution started in the Aptian, forming isolated basins with continental sedimentation. In the Albian times, a great delta developed in the Upper Benue Trough, while the first marine transgression coming from the opening Gulf of Guinea occurred in the south and reached the Middle Benue. The widespread Turonian transgression made the Atlantic and Tethys waters communicate through the Sahara, Niger basins and the Benue Trough. The tectonic evolution of the Benue Trough was closely controlled by transcurrent faulting through an axial fault system, developing local compressional and tensional regimes and resulting in basins and basement horsts along releasing and restraining bends of the faults. Two major compressional phases occurred: in the Abakaliki area (southern Benue) during the Santonian; and at the end of the Cretaceous in the Upper Benue Trough. In Abakaliki, the sedimentary infilling was severely deformed through folding and flattening, and moderate folding and fracturing occurred in the northeast. The Cretaceous magmatism was restricted to main fault zones in most of the trough but was particularly active in the Abakaliki Trough, where it has alkaline affinities. From Albian to Santonian, the magmatism was accompanied in part of the Abakaliki Trough by a low-grade metamorphism. Geophysical data indicate a crustal thinning beneath the Benue Trough and, at a superficial level, an axial basement high flanked by two elongated deep basins including isolated sub-basins. The model of the tectonic evolution of the trough is based upon a general sinistral wrenching along the trough responsible for the structural arrangement and the geometry of the sub-basins. During the early stages of the Gulf of Guinea opening the Benue Trough was probably the expression on land of the Equatorial Fracture Zones.

  10. Influence of adhesive shear deformation on laminate structural behavior with application to parabolic trough solar collectors. [SHEAR

    SciTech Connect

    Clauss, D.B.; Reuter, R.C. Jr.

    1983-02-01

    A simplified theory for the bending behavior of a thin flat bi-lamina panel is developed which includes the effects of shear deformation in the central adhesive layer. Static equilibrium equations for elastic thermomechanical cylindrical bending of a thin plate are used. A solution form is proposed which greatly facilitates application of this theory to structural panels with numerous discrete property changes in the variable direction. The influence of adhesive shear stiffness parameters upon overall laminate behavior is characterized through numerical examples typifying various thermal and mechanical loading conditions.

  11. Fifth parabolic dish solar thermal power program annual review: proceedings

    SciTech Connect

    1984-03-01

    The primary objective of the Review was to present the results of activities within the Parabolic Dish Technology and Module/Systems Development element of the Department of Energy's Solar Thermal Energy Systems Program. The Review consisted of nine technical sessions covering overall Project and Program aspects, Stirling and Brayton module development, concentrator and engine/receiver development, and associated hardware and test results to date; distributed systems operating experience; international dish development activities; and non-DOE-sponsored domestic dish activities. A panel discussion concerning business views of solar electric generation was held. These Proceedings contain the texts of presentations made at the Review, as submitted by their authors at the beginning of the Review; therefore, they may vary slightly from the actual presentations in the technical sessions.

  12. Eponym of Naso-Jugal Fold and Tear Trough.

    PubMed

    Hwang, Kun

    2016-07-01

    The aim of this study is to find out the eponym of the naso-jugal fold and tear trough and to make a suggestion to standardize the terminology.In a PubMed search, the search terms (naso-jugal) and (fold OR groove); (tear trough) and (anatomy) were used, which resulted in 48 and 37 titles, respectively. Eliminating duplicated titles, 80 abstracts were reviewed. Among them, 18 full papers were reviewed. Two papers were excluded and 3 mined papers were added. Finally, 19 papers were reviewed.In a paper published by an ophthalmologist Dr David Miller, "tear trough" was first used for designating the circular trough carved into a scleral contact in 1969. In the remaining 18 papers including 1 conference presentation, 6 terms were used for the same structure; naso-jugal fold (4), naso-jugal groove (4), naso-jugal ditch (1), tear trough (5), tear trough deformity (6), and tear trough depression (1). Whitnall first used "naso-jugal" and 10 other papers stated "naso-jugal." Eight papers cited Whitnall (2), Duke-Elder (2), and Loeb (4) in the origin of the term "naso-jugal." Flowers adapted "tear trough" for the cheek groove and 12 other papers wrote "tear trough." Eleven papers cited Flowers (9), Le Louarn (1), Mendelson (1) when referring to the origin of the term "tear trough."The name of the structure should contain "naso-jugal" rather than "tear trough" because "naso-jugal" was coined earlier and expresses the location of the structure. The recommended term should be "the deepened naso-jugal groove" since it deepens with age. PMID:27315310

  13. Numerical Schemes for Rough Parabolic Equations

    SciTech Connect

    Deya, Aurelien

    2012-04-15

    This paper is devoted to the study of numerical approximation schemes for a class of parabolic equations on (0,1) perturbed by a non-linear rough signal. It is the continuation of Deya (Electron. J. Probab. 16:1489-1518, 2011) and Deya et al. (Probab. Theory Relat. Fields, to appear), where the existence and uniqueness of a solution has been established. The approach combines rough paths methods with standard considerations on discretizing stochastic PDEs. The results apply to a geometric 2-rough path, which covers the case of the multidimensional fractional Brownian motion with Hurst index H>1/3.

  14. On the parallel solution of parabolic equations

    NASA Technical Reports Server (NTRS)

    Gallopoulos, E.; Saad, Youcef

    1989-01-01

    Parallel algorithms for the solution of linear parabolic problems are proposed. The first of these methods is based on using polynomial approximation to the exponential. It does not require solving any linear systems and is highly parallelizable. The two other methods proposed are based on Pade and Chebyshev approximations to the matrix exponential. The parallelization of these methods is achieved by using partial fraction decomposition techniques to solve the resulting systems and thus offers the potential for increased time parallelism in time dependent problems. Experimental results from the Alliant FX/8 and the Cray Y-MP/832 vector multiprocessors are also presented.

  15. Sedimentation and tectonics of the Sylhet trough, Bangladesh

    USGS Publications Warehouse

    Johnson, S.Y.; Nur Alam, A.M.

    1991-01-01

    The Sylhet trough, a sub-basin of the Bengal Basin in northeastern Bangladesh, contains a thick fill (12 to 16 km) of late Mesozoic and Cenozoic strata that record its tectonic evolution. Stratigraphic, sedimentologic, and petrographic data collected from outcrops, cores, well logs, and seismic lines are used to reconstruct the history of this trough. -from Authors

  16. 9 CFR 91.27 - Troughs and hayracks.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... and pens aboard an ocean vessel shall be equipped with proper troughs for feeding and watering animals... hay from racks or nets or by placing the hay on the floor of the pens in which the animals are... animals. (b) Sheep, goats, and swine. Pens for these animals shall have feed troughs not less than...

  17. Microgravity Active Vibration Isolation System on Parabolic Flights

    NASA Astrophysics Data System (ADS)

    Dong, Wenbo; Pletser, Vladimir; Yang, Yang

    2016-07-01

    The Microgravity Active Vibration Isolation System (MAIS) aims at reducing on-orbit vibrations, providing a better controlled lower gravity environment for microgravity physical science experiments. The MAIS will be launched on Tianzhou-1, the first cargo ship of the China Manned Space Program. The principle of the MAIS is to suspend with electro-magnetic actuators a scientific payload, isolating it from the vibrating stator. The MAIS's vibration isolation capability is frequency-dependent and a decrease of vibration of about 40dB can be attained. The MAIS can accommodate 20kg of scientific payload or sample unit, and provide 30W of power and 1Mbps of data transmission. The MAIS is developed to support microgravity scientific experiments on manned platforms in low earth orbit, in order to meet the scientific requirements for fluid physics, materials science, and fundamental physics investigations, which usually need a very quiet environment, increasing their chances of success and their scientific outcomes. The results of scientific experiments and technology tests obtained with the MAIS will be used to improve future space based research. As the suspension force acting on the payload is very small, the MAIS can only be operative and tested in a weightless environment. The 'Deutsches Zentrum für Luft- und Raumfahrt e.V.' (DLR, German Aerospace Centre) granted a flight opportunity to the MAIS experiment to be tested during its 27th parabolic flight campaign of September 2015 performed on the A310 ZERO-G aircraft managed by the French company Novespace, a subsidiary of the 'Centre National d'Etudes Spatiales' (CNES, French Space Agency). The experiment results confirmed that the 6 degrees of freedom motion control technique was effective, and that the vibration isolation performance fulfilled perfectly the expectations based on theoretical analyses and simulations. This paper will present the design of the MAIS and the experiment results obtained during the

  18. Heat and electricity from the sun using parabolic dish collector systems

    NASA Technical Reports Server (NTRS)

    Truscello, V. C.; Williams, A. N.

    1979-01-01

    The paper investigates point focus distributed receiver (PFDR) solar thermal technology for the production of electric power and of industrial process heat. Attention is given to a thermal systems project conducted by JPL under DOE sponsorship. It is reported that project emphasis is on the development of cost-effective systems which will accelerate the commercialization and industrialization of plants up to 10 MWe, using parabolic dish collectors. Also discussed are the characteristics of PFDR systems, the cost targets for major systems hardware, and markets for this technology. Finally, the present system status of the technology development effort is discussed.

  19. Characterisation of a large aperture steep concave parabolic mirror using SASI based on auto-collimation theory

    NASA Astrophysics Data System (ADS)

    Liu, Bingcai; Li, Bing; Tian, Ailing; Yang, Haoyu; Gao, Fen; Chen, Lei

    2015-01-01

    To characterise a large aperture steep concave parabolic mirror, a new sub-aperture stitching interferometry measurement technology (SASI) based on auto-collimation is proposed. The principle of the stitching process is analysed, and the sub-aperture partitioning for a full aperture of a paraboloid is discussed. Next, the overlapped sampled points between sub-apertures are rectified through sampled points realigned in mesh grids. Finally, two experiments, the SASI based on auto-collimation and the full aperture test, were implemented for a parabolic mirror. The stitching result exhibits good agreement with the full-aperture result.

  20. Parabolic flight - Loss of sense of orientation

    NASA Technical Reports Server (NTRS)

    Lackner, J. R.; Graybiel, A.

    1979-01-01

    On the earth, or in level flight, a blindfolded subject being rotated at constant velocity about his recumbent long body axis experiences illusory orbital motion of his body in the opposite direction. By contrast, during comparable rotation in the free-fall phase of parabolic flight, no body motion is perceived and all sense of external orientation may be lost; when touch and pressure stimulation is applied to the body surface, a sense of orientation is reestablished immediately. The increased gravitoinertial force period of a parabola produces an exaggeration of the orbital motion experienced in level flight. These observations reveal an important influence of touch, pressure, and kinesthetic information on spatial orientation and provide a basis for understanding many of the postural illusions reported by astronauts in space flight.

  1. Steam engine research for solar parabolic dish

    NASA Technical Reports Server (NTRS)

    Demler, R. L.

    1981-01-01

    The parabolic dish solar concentrator provides an opportunity to generate high grade energy in a modular system. Most of the capital is projected to be in the dish and its installation. Assurance of a high production demand of a standard dish could lead to dramatic cost reductions. High production volume in turn depends upon maximum application flexibility by providing energy output options, e.g., heat, electricity, chemicals and combinations thereof. Subsets of these options include energy storage and combustion assist. A steam engine design and experimental program is described which investigate the efficiency potential of a small 25 kW compound reheat cycle piston engine. An engine efficiency of 35 percent is estimated for a 700 C steam temperature from the solar receiver.

  2. Parabolic dish module experiment. Final test report

    SciTech Connect

    Not Available

    1986-03-01

    A development test model of the 8-meter Solar Brayton Parabolic Dish Module has been designed, fabricated, and tested. The test model consists of five major subsystems: Sanders ceramic honeycomb solar receiver; LaJet LEC460 solar concentrator; AiRsearch SABC MKIIIA engine, Abacus 8 kW ac inverter; and a Sanders designed and built system controller. Goals of the tests were to integrate subsystem components into a working module, demonstrate the concept, and generate 5 kWe (hybrid) and 4.7 kWe (solar only) input. All subsystem integration goals were successfully achieved, but system performance efficiency was lower than expected. Contributing causes of the lower performance efficiencies have been identified. Modifications needed to restore performance to the required levels and improve the system life cycle cost have been addressed and are the subject of this final report.

  3. Nonuniform depth grids in parabolic equation solutions.

    PubMed

    Sanders, William M; Collins, Michael D

    2013-04-01

    The parabolic wave equation is solved using a finite-difference solution in depth that involves a nonuniform grid. The depth operator is discretized using Galerkin's method with asymmetric hat functions. Examples are presented to illustrate that this approach can be used to improve efficiency for problems in ocean acoustics and seismo-acoustics. For shallow water problems, accuracy is sensitive to the precise placement of the ocean bottom interface. This issue is often addressed with the inefficient approach of using a fine grid spacing over all depth. Efficiency may be improved by using a relatively coarse grid with nonuniform sampling to precisely position the interface. Efficiency may also be improved by reducing the sampling in the sediment and in an absorbing layer that is used to truncate the computational domain. Nonuniform sampling may also be used to improve the implementation of a single-scattering approximation for sloping fluid-solid interfaces. PMID:23556565

  4. Analysis of the Quality of Parabolic Flight

    NASA Technical Reports Server (NTRS)

    Lambot, Thomas; Ord, Stephan F.

    2016-01-01

    Parabolic flight allows researchers to conduct several micro-gravity experiments, each with up to 20 seconds of micro-gravity, in the course of a single day. However, the quality of the flight environment can vary greatly over the course of a single parabola, thus affecting the experimental results. Researchers therefore require knowledge of the actual flight environment as a function of time. The NASA Flight Opportunities program (FO) has reviewed the acceleration data for over 400 parabolas and investigated the level of micro-gravity quality. It was discovered that a typical parabola can be segmented into multiple phases with different qualities and durations. The knowledge of the microgravity characteristics within the parabola will prove useful when planning an experiment.

  5. Global existence of weak solutions to quasilinear degenerate Keller-Segel systems of parabolic-parabolic type with small data

    NASA Astrophysics Data System (ADS)

    Ishida, Sachiko; Yokota, Tomomi

    This paper deals with the quasilinear degenerate Keller-Segel system (KS) of "parabolic-parabolic" type. The global existence of weak solutions to (KS) with small initial data is established when q⩾m+2/N ( m denotes the intensity of diffusion and q denotes the nonlinearity). In the system of "parabolic-elliptic" type, Sugiyama and Kunii (2006) [13, Theorem 3] and Sugiyama (2007) [12, Theorem 2] state the similar result; note that q=m+2/N corresponds to generalized Fujita's critical exponent. However, the super-critical case where q⩾m+2/N has been unsolved for "parabolic-parabolic" type. Therefore this paper gives an answer to the unsolved problem.

  6. Graviresponses of Paramecium biaurelia during parabolic flights.

    PubMed

    Krause, Martin; Bräucker, Richard; Hemmersbach, Ruth

    2006-12-01

    The thresholds of graviorientation and gravikinesis in Paramecium biaurelia were investigated during the 5th DLR (German Aerospace Center) parabolic-flight campaign at Bordeaux in June 2003. Parabolic flights are a useful tool for the investigation of swimming behaviour in protists at different accelerations. At normal gravity (1 g) and hypergravity (1 g to 1.8 g), precision of orientation and locomotion rates depend linearly on the applied acceleration as seen in earlier centrifuge experiments. After transition from hypergravity to decreased gravity (minimal residual acceleration of <10(-2) g), graviorientation as well as gravikinesis show a full relaxation with different kinetics. The use of twelve independent cell samples per flight guarantees high data numbers and secures the statistical significance of the obtained data. The relatively slow change of acceleration between periods of microgravity and hypergravity (0.4 g/s) enabled us to determine the thresholds of graviorientation at 0.6 g and of gravikinesis at 0.4 g. The gravity-unrelated propulsion rate of the sample was found to be 874 microm/s, exceeding the locomotion rate of horizontally swimming cells (855 microm/s). The measured thresholds of graviresponses were compared with data obtained from earlier centrifuge experiments on the sounding rocket Maxus-2. Measured thresholds of gravireactions indicate that small energies, close to the thermal noise level, are sufficient for the gravitransduction process. Data from earlier hypergravity experiments demonstrate that mechanosensitive ion channels are functioning over a relative wide range of acceleration. From this, we may speculate that gravireceptor channels derive from mechanoreceptor channels. PMID:17180491

  7. Cobbles in Troughs Between Meridiani Ripples

    NASA Technical Reports Server (NTRS)

    2006-01-01

    As NASA's Mars Exploration Rover Opportunity continues to traverse from 'Erebus Crater' toward 'Victoria Crater,' the rover navigates along exposures of bedrock between large, wind-blown ripples. Along the way, scientists have been studying fields of cobbles that sometimes appear on trough floors between ripples. They have also been studying the banding patterns seen in large ripples.

    This view, obtained by Opportunity's panoramic camera on the rover's 802nd Martian day (sol) of exploration (April 27, 2006), is a mosaic spanning about 30 degrees. It shows a field of cobbles nestled among wind-driven ripples that are about 20 centimeters (8 inches) high.

    The origin of cobble fields like this one is unknown. The cobbles may be a lag of coarser material left behind from one or more soil deposits whose finer particles have blown away. The cobbles may be eroded fragments of meteoritic material, secondary ejecta of Mars rock thrown here from craters elsewhere on the surface, weathering remnants of locally-derived bedrock, or a mixture of these. Scientists will use the panoramic camera's multiple filters to study the rock types, variability and origins of the cobbles.

    This is an approximately true-color rendering that combines separate images taken through the panoramic camera's 753-nanometer, 535-nanometer and 432-nanometer filters.

  8. Interior trough deposits on Mars: Subice volcanoes?

    USGS Publications Warehouse

    Chapman, M.G.; Tanaka, K.L.

    2001-01-01

    Widespread, several-kilometer-thick successions of layered deposits occur as mounds that partly fill the troughs or chasmata that compose the Valles Marineris on Mars. Like terrestrial subice volcanoes, the layered deposits occur in a volcano-tectonic setting within basins that may have held ponded water or ice. On the basis of their dimensions, morphologies, and associated catastrophic floods and other geologic events as shown in Viking and new Mars Global Surveyor (MGS) data sets, we suggest that the interior deposits are volcanic in origin and possibly generated by subice eruptions. A tuya origin for the mounds can explain the lack of external sediment, mound heights that can rival the plateau, local flat-topped mesas, morphologically distinct mounds of different ages, horizontal to steep dips, fine-grained materials, indications of rare volcanic vents and lava flows, and spectral composition. The extremely diverse layering of west Candor Chasma and possible volcanic cones in Melas may have formed by related subaerial eruptions. Consistent with the suggestion that interior deposits are eroding out of the wall rock, some deposits could have been erupted from sites along the walls.

  9. GPS/acoustic Seafloor Geodetic Observations Near the Nankai Trough Axis

    NASA Astrophysics Data System (ADS)

    Tadokoro, K.; Yasuda, K.; Fujii, C.; Watanabe, T.; Nagai, S.

    2013-12-01

    installed a new seafloor benchmark in the vicinity of the Nankai Trough axis, about 15 km landward from the trough axis, on July 16, 2013. In addition, we plan to install another new benchmark on the other side of the Nankai Trough in August of this year, to directly measure the motion of the subducting Philippine Sea Plate. The coupling ratio is calculated from slip deficit divided by convergence rate. We can directly 'measure' the coupling ratio from crustal deformation at the newly-installed station on the Philippine Sea Plate, without using global plate motion models. Acknowledgments: We are grateful to the captain and crews of R/V "Asama" of Mie Prefecture Fisheries Research Institute, Japan. This study has been partly promoted by Ministry of Education, Culture, Sports, Science and Technology, Japanese Government.

  10. DETAIL VIEW OF CLASSIFIER, TAILINGS LAUNDER TROUGH, LINESHAFTS, AND CONCENTRATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF CLASSIFIER, TAILINGS LAUNDER TROUGH, LINESHAFTS, AND CONCENTRATION TABLES WITH SIX FOOT SCALE, LOOKING SOUTHWEST. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

  11. "Cheese" room in halfcellar showing stone trough, later fireplace supports, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    "Cheese" room in half-cellar showing stone trough, later fireplace supports, stairs inserted in original relieving arch. - Scheetz Farm, House, 7161 Camp Hill Road, Fort Washington, Montgomery County, PA

  12. Troughs under threshold modeling of minimum flows in perennial streams

    NASA Astrophysics Data System (ADS)

    Önöz, B.; Bayazit, M.

    2002-02-01

    Troughs under threshold analysis has so far found little application in the modeling of minimum streamflows. In this study, all the troughs under a certain threshold level are considered in deriving the probability distribution of annual minima through the total probability theorem. For the occurrence of minima under the threshold, Poissonian, binomial or negative binomial processes are assumed. The magnitude of minima follows the generalized Pareto, exponential or power distribution. It is shown that asymptotic extreme value distributions for minima or the two-parameter Weibull distribution is obtained for the annual minima, depending on which models are assumed for the occurrence and magnitude of troughs under the threshold. Derived distributions can be used for modeling the minimum flows in streams which do not have zero flows. Expressions for the T-year annual minimum flow are obtained. An example illustrates the application of the troughs under threshold model to the minimum flows observed in a stream.

  13. Detail view of concrete trough and metal stanchions at east ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail view of concrete trough and metal stanchions at east side of middle level, with scale stick - St. Elizabeths Hospital, Cow Barn, 2700 Martin Luther King Jr Avenue SE, Washington, District of Columbia, DC

  14. 6. VIEW SOUTHWEST, COOLING TROUGH REMAINS Imperial Carbon Black ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW SOUTHWEST, COOLING TROUGH REMAINS - Imperial Carbon Black Plant (Ruin), North side of North Fork of Hughes River along Bunnell Run Road just over 0.5 mile from its intersection with State Route 16, Harrisville, Ritchie County, WV

  15. Comparison of Non-Parabolic Hydrodynamic Simulations for Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Smith, A. W.; Brennan, K. F.

    1996-01-01

    Parabolic drift-diffusion simulators are common engineering level design tools for semiconductor devices. Hydrodynamic simulators, based on the parabolic band approximation, are becoming more prevalent as device dimensions shrink and energy transport effects begin to dominate device characteristic. However, band structure effects present in state-of-the-art devices necessitate relaxing the parabolic band approximation. This paper presents simulations of ballistic diodes, a benchmark device, of Si and GaAs using two different non-parabolic hydrodynamic formulations. The first formulation uses the Kane dispersion relationship in the derivation of the conservation equations. The second model uses a power law dispersion relation {(hk)(exp 2)/2m = xW(exp Y)}. Current-voltage relations show that for the ballistic diodes considered. the non-parabolic formulations predict less current than the parabolic case. Explanations of this will be provided by examination of velocity and energy profiles. At low bias, the simulations based on the Kane formulation predict greater current flow than the power law formulation. As the bias is increased this trend changes and the power law predicts greater current than the Kane formulation. It will be shown that the non-parabolicity and energy range of the hydrodynamic model based on the Kane dispersion relation are limited due to the binomial approximation which was utilized in the derivation.

  16. What is the intrapatient variability of mycophenolic acid trough levels?

    PubMed

    Todorova, Ekaterina K; Huang, Shih-Han S; Kobrzynski, Marta C; Filler, Guido

    2015-11-01

    TDM of MPA, the active compound of MMF, is rarely used despite its substantial intra- and interpatient variability. Little is known about the utility of long-term MPA TDM. Data are expressed as mean (one standard deviation). All available data from 27 renal transplant recipients (mean age at transplantation: 7.7 [5.0] yr) with an average follow-up of 9.3 (4.6) yr were analyzed. MPA levels were measured using the EMIT. GFR was measured using cystatin C and eGFR was calculated using the Filler formula. Intrapatient CV of the trough level was calculated as the ratio of the mean divided by one standard deviation. Mean cystatin C eGFR was 56.9 (24.4) mL/min/1.73 m(2) . There was a weak but significant correlation between the MPA trough level and the AUC (Spearman r = 0.6592, p < 0.0001). A total of 1964 MPA trough levels (73 [45]/patient) were measured, as compared to 3462 Tac trough levels (144 [71]/patient). The average MPA trough level was 3.01 (1.26) mg/L and the average trough Tac level was 7.3 (1.8) ng/mL. Intrapatient CV was statistically higher (p = 0.00093) for MPA at 0.68 (0.29) when compared to Tac with a CV of 0.46 (0.12). CV did not correlate with eGFR. Intrapatient MPA trough level CV is significantly higher than for Tac, while CV for both MPA and Tac was high. MPA trough level monitoring may be a feasible monitoring option to improve patient exposure and possibly outcomes. PMID:26201386

  17. A study on optical aberrations in parabolic neutron guides

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Wang, Hongli; Liu, Yuntao; Zu, Yong; He, Linfeng; Wei, Guohai; Sun, Kai; Han, Songbai; Chen, Dongfeng

    2015-06-01

    It is widely believed that a neutron beam can be focused to a small spot using a parabolic guide, which will significantly improve the flux. However, researchers have also noted challenges for the neutron inhomogeneous phase space distribution in parabolic focusing guide systems. In this paper, the sources of most prominent optical aberrations, such as an inhomogeneous phase space distribution and irregular divergence distribution, are discussed, and an optimization solution is also proposed. We indicate that optimizing the parabolic guide geometrical configuration removes almost all of the aberrations and yields a considerable intensity gain factor.

  18. Weak lensing by galaxy troughs in DES Science Verification data

    DOE PAGESBeta

    Gruen, D.; Friedrich, O.; Amara, A.; Bacon, D.; Bonnett, C.; Hartley, W.; Jain, B.; M. Jarvis; Kavprzak, T.; Krause, E.; et al

    2015-11-29

    In this study, we measure the weak lensing shear around galaxy troughs, i.e. the radial alignment of background galaxies relative to underdensities in projections of the foreground galaxy field over a wide range of redshift in Science Verification data from the Dark Energy Survey. Our detection of the shear signal is highly significant (10σ–15σ for the smallest angular scales) for troughs with the redshift range z ϵ [0.2, 0.5] of the projected galaxy field and angular diameters of 10 arcmin…1°. These measurements probe the connection between the galaxy, matter density, and convergence fields. By assuming galaxies are biased tracers ofmore » the matter density with Poissonian noise, we find agreement of our measurements with predictions in a fiducial Λ cold dark matter model. The prediction for the lensing signal on large trough scales is virtually independent of the details of the underlying model for the connection of galaxies and matter. Our comparison of the shear around troughs with that around cylinders with large galaxy counts is consistent with a symmetry between galaxy and matter over- and underdensities. In addition, we measure the two-point angular correlation of troughs with galaxies which, in contrast to the lensing signal, is sensitive to galaxy bias on all scales. The lensing signal of troughs and their clustering with galaxies is therefore a promising probe of the statistical properties of matter underdensities and their connection to the galaxy field.« less

  19. Weak Lensing by Galaxy Troughs in DES Science Verification Data

    SciTech Connect

    Gruen, D.

    2015-09-29

    We measure the weak lensing shear around galaxy troughs, i.e. the radial alignment of background galaxies relative to underdensities in projections of the foreground galaxy field over a wide range of redshift in Science Verification data from the Dark Energy Survey. Our detection of the shear signal is highly significant (10σ–15σ for the smallest angular scales) for troughs with the redshift range z ϵ [0.2, 0.5] of the projected galaxy field and angular diameters of 10 arcmin…1°. These measurements probe the connection between the galaxy, matter density, and convergence fields. By assuming galaxies are biased tracers of the matter density with Poissonian noise, we find agreement of our measurements with predictions in a fiducial Λ cold dark matter model. Furthermore, the prediction for the lensing signal on large trough scales is virtually independent of the details of the underlying model for the connection of galaxies and matter. Our comparison of the shear around troughs with that around cylinders with large galaxy counts is consistent with a symmetry between galaxy and matter over- and underdensities. In addition, we measure the two-point angular correlation of troughs with galaxies which, in contrast to the lensing signal, is sensitive to galaxy bias on all scales. Finally, the lensing signal of troughs and their clustering with galaxies is therefore a promising probe of the statistical properties of matter underdensities and their connection to the galaxy field.

  20. Weak lensing by galaxy troughs in DES Science Verification data

    NASA Astrophysics Data System (ADS)

    Gruen, D.; Friedrich, O.; Amara, A.; Bacon, D.; Bonnett, C.; Hartley, W.; Jain, B.; Jarvis, M.; Kacprzak, T.; Krause, E.; Mana, A.; Rozo, E.; Rykoff, E. S.; Seitz, S.; Sheldon, E.; Troxel, M. A.; Vikram, V.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Armstrong, R.; Banerji, M.; Bauer, A. H.; Becker, M. R.; Benoit-Lévy, A.; Bernstein, G. M.; Bernstein, R. A.; Bertin, E.; Bridle, S. L.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Neto, A. Fausti; Fernandez, E.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gerdes, D. W.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; Maia, M. A. G.; March, M.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nord, B.; Ogando, R.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Thomas, D.; Walker, A. R.; Wechsler, R. H.; Weller, J.; Zhang, Y.; Zuntz, J.

    2016-01-01

    We measure the weak lensing shear around galaxy troughs, i.e. the radial alignment of background galaxies relative to underdensities in projections of the foreground galaxy field over a wide range of redshift in Science Verification data from the Dark Energy Survey. Our detection of the shear signal is highly significant (10σ-15σ for the smallest angular scales) for troughs with the redshift range z ∈ [0.2, 0.5] of the projected galaxy field and angular diameters of 10 arcmin…1°. These measurements probe the connection between the galaxy, matter density, and convergence fields. By assuming galaxies are biased tracers of the matter density with Poissonian noise, we find agreement of our measurements with predictions in a fiducial Λ cold dark matter model. The prediction for the lensing signal on large trough scales is virtually independent of the details of the underlying model for the connection of galaxies and matter. Our comparison of the shear around troughs with that around cylinders with large galaxy counts is consistent with a symmetry between galaxy and matter over- and underdensities. In addition, we measure the two-point angular correlation of troughs with galaxies which, in contrast to the lensing signal, is sensitive to galaxy bias on all scales. The lensing signal of troughs and their clustering with galaxies is therefore a promising probe of the statistical properties of matter underdensities and their connection to the galaxy field.

  1. Weak lensing by galaxy troughs in DES Science Verification data

    SciTech Connect

    Gruen, D.; Friedrich, O.; Amara, A.; Bacon, D.; Bonnett, C.; Hartley, W.; Jain, B.; M. Jarvis; Kavprzak, T.; Krause, E.; Mana, A.; Rozo, E.; Rykoff, E. S.; Seitz, S.; Sheldon, E.; Troxel, M. A.; Vikram, V.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Armstrong, R.; Banerji, M.; Bauer, A. H.; Becker, M. R.; Benoit-Levy, A.; Bernstein, G. M.; Bernstein, R. A.; Bertin, E.; Bridle, S. L.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Rosell, A. Carnero; Carretero, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Neto, A. Fausti; Fernandez, E.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gerdes, D. W.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; Maia, M. A. G.; March, M.; Martini, P.; Melchior, P.; Miller, C. J.; Miguel, R.; Mohr, J. J.; Nord, B.; Orgando, R.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Thomas, D.; Walker, A. R.; Wechsler, R. H.; Weller, J.; Zhang, Y.; Zuntz, J.

    2015-11-29

    In this study, we measure the weak lensing shear around galaxy troughs, i.e. the radial alignment of background galaxies relative to underdensities in projections of the foreground galaxy field over a wide range of redshift in Science Verification data from the Dark Energy Survey. Our detection of the shear signal is highly significant (10σ–15σ for the smallest angular scales) for troughs with the redshift range z ϵ [0.2, 0.5] of the projected galaxy field and angular diameters of 10 arcmin…1°. These measurements probe the connection between the galaxy, matter density, and convergence fields. By assuming galaxies are biased tracers of the matter density with Poissonian noise, we find agreement of our measurements with predictions in a fiducial Λ cold dark matter model. The prediction for the lensing signal on large trough scales is virtually independent of the details of the underlying model for the connection of galaxies and matter. Our comparison of the shear around troughs with that around cylinders with large galaxy counts is consistent with a symmetry between galaxy and matter over- and underdensities. In addition, we measure the two-point angular correlation of troughs with galaxies which, in contrast to the lensing signal, is sensitive to galaxy bias on all scales. The lensing signal of troughs and their clustering with galaxies is therefore a promising probe of the statistical properties of matter underdensities and their connection to the galaxy field.

  2. Correction of Tear Trough Deformity With a Cohesive Polydensified Matrix Hyaluronic Acid: A Case Series.

    PubMed

    Huber-Vorländer, Jürgen; Kürten, Martin

    2015-01-01

    The tear trough or infraorbital hollow is a challenging area to treat, and only a few fillers are suitable for this delicate area. We report on a European case series of six subjects with mild to severe tear troughs who received treatment with cohesive polydensified matrix (CPM®) technology hyaluronic acid gel (Belotero® Balance). The product was injected as small depots (up to ten small boli 0.2 mL maximum each per side) at the supraperiosteal level along or below the orbital rim. Follow-up visits took place at 1, 3, 6, and 9 months after injection for independent evaluation of the clinical effect using the Merz Aesthetics Scale™ for infraorbital hollows and the Global Aesthetic Improvement Scale. Adverse events were also recorded. Mean hollowness scores were considerably improved compared with baseline in all subjects. In all women, the improvements remained throughout the 9-month study, with none reverting to their baseline score. Subjects' satisfaction with treatment was very high throughout the study, and all women stated that they would repeat treatment with the same product. The CPM hyaluronic acid gel was well tolerated. CPM hyaluronic acid gel is a safe and effective treatment for the tear trough area. PMID:26605822

  3. Correction of tear trough deformity with a cohesive polydensified matrix hyaluronic acid: a case series.

    PubMed

    Huber-Vorländer, Jürgen; Kürten, Martin

    2015-01-01

    The tear trough or infraorbital hollow is a challenging area to treat, and only a few fillers are suitable for this delicate area. We report on a European case series of six subjects with mild to severe tear troughs who received treatment with cohesive polydensified matrix (CPM(®)) technology hyaluronic acid gel (Belotero(®) Balance). The product was injected as small depots (up to ten small boli 0.2 mL maximum each per side) at the supraperiosteal level along or below the orbital rim. Follow-up visits took place at 1, 3, 6, and 9 months after injection for independent evaluation of the clinical effect using the Merz Aesthetics Scale™ for infraorbital hollows and the Global Aesthetic Improvement Scale. Adverse events were also recorded. Mean hollowness scores were considerably improved compared with baseline in all subjects. In all women, the improvements remained throughout the 9-month study, with none reverting to their baseline score. Subjects' satisfaction with treatment was very high throughout the study, and all women stated that they would repeat treatment with the same product. The CPM hyaluronic acid gel was well tolerated. CPM hyaluronic acid gel is a safe and effective treatment for the tear trough area. PMID:26170706

  4. Correction of tear trough deformity with a cohesive polydensified matrix hyaluronic acid: a case series

    PubMed Central

    Huber-Vorländer, Jürgen; Kürten, Martin

    2015-01-01

    The tear trough or infraorbital hollow is a challenging area to treat, and only a few fillers are suitable for this delicate area. We report on a European case series of six subjects with mild to severe tear troughs who received treatment with cohesive polydensified matrix (CPM®) technology hyaluronic acid gel (Belotero® Balance). The product was injected as small depots (up to ten small boli 0.2 mL maximum each per side) at the supraperiosteal level along or below the orbital rim. Follow-up visits took place at 1, 3, 6, and 9 months after injection for independent evaluation of the clinical effect using the Merz Aesthetics Scale™ for infraorbital hollows and the Global Aesthetic Improvement Scale. Adverse events were also recorded. Mean hollowness scores were considerably improved compared with baseline in all subjects. In all women, the improvements remained throughout the 9-month study, with none reverting to their baseline score. Subjects’ satisfaction with treatment was very high throughout the study, and all women stated that they would repeat treatment with the same product. The CPM hyaluronic acid gel was well tolerated. CPM hyaluronic acid gel is a safe and effective treatment for the tear trough area. PMID:26170706

  5. On two parabolic systems: Convergence and blowup

    NASA Astrophysics Data System (ADS)

    Huang, Yamin

    1998-12-01

    This dissertation studies two parabolic systems. It consists of two parts. In part one (chapter one), we prove a convergence result, namely, the solution (AK,/ BK) of a system of chemical diffusion-reaction equations (with reaction rate K) converges to the solution (A, B) of a diffusion- instantaneous-reaction equation. To prove our main result, we use some L1 and L2 'energy' estimates and a compactness result due to Aubin (1). As a by-product we also prove that as K approaches infinity, the limit solution exhibits phase separation between A and B. In part two (chapter two), we study the blowup rate for a system of heat equations ut=/Delta u,/ vt=/Delta v in a bounded domain Ωtimes(0,T) coupled in the nonlinear Neumann boundary conditions [/partial u/over/partial n]=vp,/ [/partial v/over/partial n]=uq on ∂Omega×[ 0,T), where p>0,/ q>0,/ pq>1 and n is the exterior normal vector on ∂Omega. Under certain assumptions, we establish exact blowup rate which generalizes the corresponding results of some authors' recent work including Deng (2), Deng-Fila-Levine (3) and Hu-Yin (4). ftn (1) J. P. A scUBIN, Un theoreme de compacite, C. R. Acad. Sci., 256(1963), pp. 5042-5044. (2) K. D scENG, Blow-up rates for parabolic systems, Z. Angew. Math. Phys., 47(1996), No. 1, pp. 132-143. (3) K. D scENG, M. F scILA AND H. A. L scEVINE, On critical exponents for a system of heat equations coupled in the boundary conditions, Acta Math. Univ. Comenian. (N.S.), 36(1994), No. 2, pp. 169-192. (4) B. H scU scAND H. M. Y scIN, The profile near blowup time for solutions of the heat equation with a nonlinear boundary condition, Trans. Amer. Math. Soc., 346(1994), pp. 117-135.

  6. Offset semi-parabolic nanoantenna made of a photonic crystal parabolic mirror and a plasmonic bow-tie antenna.

    PubMed

    Hattori, Haroldo T

    2014-10-10

    In a parabolic mirror, light coming parallel to the antenna passes through its focal point. In this work, a waveguide feeds a semi-parabolic photonic crystal mirror and the emerging beam feeds a bow-tie antenna placed at the mirror's focal point-it is shown that the antenna system can not only feed a bow-tie antenna (producing a localized moderately high electric field) but also produces a directional radiation beam. The semi-parabolic mirror is also modified to reduce reflection back to the feeding waveguide. PMID:25322381

  7. Monitoring of Seafloor Crustal Deformation Along the Suruga-Nankai Trough, Japan

    NASA Astrophysics Data System (ADS)

    Tadokoro, K.; Watanabe, T.; Nagai, S.; Okuda, T.; Ikuta, R.; Eto, S.; Yasuda, K.; Sakata, T.; Sayanagi, K.

    2011-12-01

    \\ \\ \\ The Suruga-Nankai Trough is one of the active plate boundaries in the world. The Philippine Sea plate subducts beneath the Amurian (Eurasian) plate along the Suruga-Nankai Trough, causing major subduction earthquakes. The subduction earthquakes, Nankai and Tonankai earthquakes, have repeatedly occurred with intervals of about 100-150 years. Headquarters for Earthquake Research Promotion, Japanese Government [2011] estimates the 30-years probabilities of the next major earthquakes at 60-70 %. It is necessary to monitor crustal deformation above the source regions of the major earthquakes. The source regions are located beneath the seafloor, and we developed a system for monitoring seafloor crustal deformation [Tadokoro et al., 2006, GRL; Ikuta et al., 2008, JGR]. The system is composed of the precise acoustic ranging with ultrasonic waves and kinematic GPS positioning techniques. \\ \\ \\ We monitor seafloor crustal deformation at five sites altogether along the Suruga-Nankai Trough, three in the Kumano region and two in the Suruga region, with the use of this system. We have repeatedly measured the coordinate of seafloor benchmark installed beforehand every about 2-3 months on the average. The monitoring results, the horizontal site velocities with relative to the Amurian Plate, as of 2010 are approximately 3-4 cm/yr in the direction of N70W at the three sites in the Kumano region, and approximately 2-4 cm/yr in the direction of N85-100W at the two sites in the Suruga region. The observed horizontal seafloor crustal deformations are consistent to the plate convergence along the Suruga-Nankai Trough, showing strain accumulation before the next major subduction earthquakes. Acknowledgments: We are grateful to the captain and crews of R/Vs "Hokuto," Tokai University and "Asama," Mie Prefecture Fisheries Research Institute, Japan. This study has been promoted by Ministry of Education, Culture, Sports, Science and Technology, Japanese Government.

  8. Transparent boundary conditions for iterative high-order parabolic equations

    NASA Astrophysics Data System (ADS)

    Petrov, P. S.; Ehrhardt, M.

    2016-05-01

    Recently a new approach to the construction of high-order parabolic approximations for the Helmholtz equation was developed. These approximations have the form of the system of iterative parabolic equations, where the solution of the n-th equation is used as an input term for the (n + 1)-th equation. In this study the transparent boundary conditions for such systems of coupled parabolic equations are derived. The existence and uniqueness of the solution of the initial boundary value problem for the system of iterative parabolic equations with the derived boundary conditions are proved. The well-posedness of this problem is also established and an unconditionally stable finite difference scheme for its solution is proposed.

  9. The French thermo-helio-electricity-KW parabolic dish program

    NASA Technical Reports Server (NTRS)

    Audibert, M.; Peri, G.

    1982-01-01

    The testing and development of parabolic dish solar thermal power plants to produce, thermal mechanical, or electrical energy are discussed. The design, construction, and experiments of prototype collectors to prove the feasibility of such collectors is described.

  10. Generalization of the rotated parabolic equation to variable slopes.

    PubMed

    Outing, Donald A; Siegmann, William L; Collins, Michael D; Westwood, Evan K

    2006-12-01

    The rotated parabolic equation [J. Acoust. Soc. Am. 87, 1035-1037 (1990)] is generalized to problems involving ocean-sediment interfaces of variable slope. The approach is based on approximating a variable slope in terms of a series of constant slope regions. The original rotated parabolic equation algorithm is used to march the field through each region. An interpolation-extrapolation approach is used to generate a starting field at the beginning of each region beyond the one containing the source. For the elastic case, a series of operators is applied to rotate the dependent variable vector along with the coordinate system. The variable rotated parabolic equation should provide accurate solutions to a large class of range-dependent seismo-acoustics problems. For the fluid case, the accuracy of the approach is confirmed through comparisons with reference solutions. For the elastic case, variable rotated parabolic equation solutions are compared with energy-conserving and mapping solutions. PMID:17225384

  11. Detail, external parabolic antenna (later addition). Note how waveguide was ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail, external parabolic antenna (later addition). Note how waveguide was cut to remove active portion of antenna. - Western Union Telegraph Company, Jennerstown Relay, Laurel Summit Road off U.S. 30, Laughlintown, Westmoreland County, PA

  12. Antenna cab interior showing waveguide from external parabolic antenna (later ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Antenna cab interior showing waveguide from external parabolic antenna (later addition), looking north. - Western Union Telegraph Company, Jennerstown Relay, Laurel Summit Road off U.S. 30, Laughlintown, Westmoreland County, PA

  13. 33. July 1958 PARABOLIC BRICK VAULT IN SERVICE MAGAZINE UNDER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. July 1958 PARABOLIC BRICK VAULT IN SERVICE MAGAZINE UNDER RAVELIN (CIVIL WAR PERIOD) - Fort McHenry National Monument & Historic Shrine, East Fort Avenue at Whetstone Point, Baltimore, Independent City, MD

  14. An X-band parabolic antenna based on gradient metasurface

    NASA Astrophysics Data System (ADS)

    Yao, Wang; Yang, Helin; Huang, Xiaojun; Tian, Ying; Guo, Linyan

    2016-07-01

    We present a novel parabolic antenna by employing reflection gradient metasurface which is composed of a series of circle patches on a grounded dielectric substrate. Similar to the traditional parabolic antenna, the proposed antenna take the metasurface as a "parabolic reflector" and a patch antenna was placed at the focal point of the metasurface as a feed source, then the quasi-spherical wave emitted by the source is reflected and transformed to plane wave with high efficiency. Due to the focus effect of reflection, the beam width of the antenna has been decreased from 85.9° to 13° and the gain has been increased from 6.5 dB to 20.8 dB. Simulation and measurement results of both near and far-field plots demonstrate good focusing properties of the proposed parabolic antenna.

  15. Parabolic dish test site: History and operating experience

    NASA Technical Reports Server (NTRS)

    Selcuk, M. K. (Compiler)

    1985-01-01

    The parabolic dish test site (PDTS) was established for testing point-focusing solar concentrator systems operating at temperatures approaching 1650 C. Among tests run were evaluation and performance characterization of parabolic dish concentrators, receivers, power conversion units, and solar/fossil-fuel hybrid systems. The PDTS was fully operational until its closure in June, 1984. The evolution of the test program, a chronological listing of the experiments run, and data summaries for most of the tests conducted are presented.

  16. Daytime F layer trough observed on a macroscopic scale

    SciTech Connect

    Whalen, J.A. )

    1987-03-01

    This paper reports a new technique of observing the high-latitude ionospheric trough which defines its continuity in space and time on a macroscopic scale not previously possible. Vertical ionospheric soundings provide the observations in the midday to evening sector where the signature of the trough is found to be a bite-out' of a factor of 3-10 in the diurnal distribution of the solar produced electron density at the F layer maximum. The data base employed is that produced by the extensive array of ionospheric sounders operating at high latitudes in the northern hemisphere during the International Geophysical Year period of December 1958, hence at solar maximum. The worldwide extent, high density, simultaneity, and continuity of these measurements make possible the description of the trough for the first time as an integral, spatially continuous entity in its entire daytime extent and UT duration. The technique is demonstrated in studies of 4 days which span the range of activity for the month. On the most disturbed day the daytime trough is continuous in magnetic latitude, magnetic local time between (75{degree}, 1030) and (51{degree}, 1630) and remains nearly stationary in this frame of reference for a duration of 14.5 hours UT. A snapshot' constructed from multiple simultaneous observations on this day shows the trough to have a continuous length of 6 {times} 10{sup 3} km and an area of > 4 {times} 10{sup 6} km{sup 2}. The trough, which is also stable for similar durations on the other 3 days, is found to rotate clockwise to earlier magnetic local time by 5.5. hours and to expand equatorward in magnetic latitude by 20{degree} as activity increases from quiet to disturbed. Activity dependence and morphology are consistent with other observations that the trough locates rapid westward convection within the dusk convection cell.

  17. Errors in trough: peak ratio determinations induced by patient behaviour.

    PubMed

    Dutrey-Dupagne; Vaur; Genès; Mallion; Meredith; Elkik

    1996-06-01

    BACKGROUND: Trough: peak ratio is often used to evaluate the duration of antihypertensive action. Whatever the method of measurement chosen, trough effect has to be measured 24 h after the last drug intake for a once daily regimen. Peak effect is usually measured 4-6 h after drug intake. If patients' compliance to therapeutic instructions is perfect, then the 'intrinsic' trough: peak ratio of the drug is equal to the measured trough: peak ratio. Some patients do not follow these instructions, leading to biases in the evaluation of the ratio. For trough evaluation, all patients (N) are supposed to take the last dose of the drug the day before blood pressure measurement. However, if some patients (n1) wrongly take the drug in the morning of the visit, they will be evaluated at peak (type A error). For peak evaluation, all patients (N) are supposed to take the drug a few hours before blood pressure measurement. If some patients (n2) miss their morning dose, they will be evaluated at trough (type B error). METHODS: In the MACH 1 study, the use of an electronic pill count monitor allowed us to quantify n1/N and n2/N. A total of 452 hypertensive patients were randomly assigned to two groups. Patients in group 1 received written instructions to take their last dose during the morning of the day before the visit, whereas patients of group 2 had to take their last dose on the morning of the visit. RESULTS: Electronic pill-box recording revealed that 32.9%: of patients in group 1 committed type A error, whereas 27.7% of patients in group 2 committed type B error. The resulting 'pill-box corrected' trough: peak ratio was lower (87.5% for diastolic blood pressure and 93.1% for systolic blood pressure) than the uncorrected trough: peak ratio (95.2% for diastolic blood pressure and 96.0% for systolic blood pressure) of the population. CONCLUSION: The random behaviour of patients, with respect to treatment compliance, results in a systematic overestimation of the measured trough

  18. Tear trough deformity: review of anatomy and treatment options.

    PubMed

    Stutman, Ross L; Codner, Mark A

    2012-05-01

    The lower eyelid can be a challenging area in facial rejuvenation. While lower eyelid bags are commonly the reason that patients present for lower eyelid rejuvenation, a separate entity known as a tear trough deformity may occur in conjunction with lower eyelid bags or alone. In this article, the authors outline the current understanding of the tear trough anatomy; describe multiple classification systems, which provide an objective means of evaluating the deformity and aid the surgeon in choosing appropriate treatment options; and review surgical and nonsurgical techniques for correcting the tear trough deformity. Treatment options include hyaluronic acid filler, fat grafting, skeletal implants, and fat transposition. Each procedure is associated with advantages and disadvantages, and each should be considered more complex than traditional lower blepharoplasty alone. While lower blepharoplasty removes excess fat and may tighten the anterior lamella, tear trough procedures require the addition of volume to the underlying depression. These procedures requiring release of the ligamentous structures and orbicularis (of which the tear trough is composed), as well as fat transposition or fat grafting, are associated with additional complications, which are also reviewed. PMID:22523096

  19. Tear trough deformity: different types of anatomy and treatment options

    PubMed Central

    Jiang, Jindou; Wang, Xuekun; Chen, Rongrong; Xia, Xueying; Sun, Sai

    2016-01-01

    Aim To explore the efficacy of tear trough deformity treatment with the use of hyaluronic acid gel or autologous fat for soft tissue augmentation and fat repositioning via arcus marginalis release. Material and methods Seventy-eight patients with the tear trough were divided into three groups. Class I has tear trough without bulging orbital fat or excess of the lower eyelid skin. Class II is associated with mild to moderate orbital fat bulging, without excess of the lower eyelid skin. Class III is associated with severe orbital fat bulging and excess of the lower eyelid skin. Class I or II was treated using hyaluronic acid gel or autologous fat injections. Class III was treated with fat repositioning via arcus marginalis release. The patients with a deep nasojugal groove of class III were treated with injecting autologous fat into the tear trough during fat repositioning lower blepharoplasty as a way of supplementing the volume added by the repositioned fat. Results Seventy-eight patients with tear trough deformity were confirmed from photographs taken before and after surgery. There were some complications, but all had complete resolution. Conclusions Patients with mild to moderate peri-orbital volume loss without severe orbital fat bulging may be good candidates for hyaluronic acid filler or fat grafting alone. However, patients with more pronounced deformities, severe orbital fat bulging and excess of the lower eyelid skin are often better served by fat repositioning via arcus marginalis release and fat grafting. PMID:27605904

  20. Aeolian Sediment Transport Pathways and Aerodynamics at Troughs on Mars

    NASA Technical Reports Server (NTRS)

    Bourke, Mary C.; Bullard, Joanna E.; Barnouin-Jha, Olivier S.

    2004-01-01

    Interaction between wind regimes and topography can give rise to complex suites of aeolian landforms. This paper considers aeolian sediment associated wit11 troughs on Mars and identifies a wider range of deposit types than has previously been documented. These include wind streaks, falling dunes, "lateral" dunes, barchan dunes, linear dunes, transverse ridges, sand ramps, climbing dunes, sand streamers, and sand patches. The sediment incorporated into these deposits is supplied by wind streaks and ambient Planitia sources as well as originating within the trough itself, notably from the trough walls and floor. There is also transmission of sediment between dneTsh. e flow dynamics which account for the distribution of aeolian sediment have been modeled using two-dimensional computational fluid dynamics. The model predicts flow separation on the upwind side of the trough followed by reattachment and acceleration at the downwind margin. The inferred patterns of sediment transport compare well with the distribution of aeolian forms. Model data indicate an increase of wind velocity by approx. 30 % at the downwind trough margin. This suggests that the threshold wind speed necessary for sand mobilization on Mars will be more freqentmlye t in these inclined locations.

  1. Parabolic Mirror: Focusing on Science, Technology, Engineering, and Math

    ERIC Educational Resources Information Center

    Smith, Karianne; Hughes, William

    2013-01-01

    In the fall of 2011, Park Forest Middle School (PFMS) students approached the STEM faculty with numerous questions regarding the popular television show Myth Busters, which detailed Greek mathematician, physicist, engineer, and inventor, Archimedes. Two episodes featured attempts to test historical accounts that Archimedes developed a death ray…

  2. Tectonic evolution of the Tobago Trough forearc basin

    NASA Technical Reports Server (NTRS)

    Speed, R.; Torrini, R., Jr.; Smith, P. L.

    1989-01-01

    The histories of configurational changes and sedimentation in the Tobago Trough, which is a modern bathymetric forearc basin of the Lesser Antilles island arc, were investigated using marine seismic data from the Tobago Trough. Special attention is given to two tectonic problems. The first is the evolution of the southeastern corner of the Caribbean as related to the finding that the early forearc basins had substantially different configurations from that of the modern forearc basin. The second is the interaction between the forearc basin and the accretionary prism within the Lesser Antilles system. It is pointed out that Miocene and younger features of the Tobago Trough might reflect a superposition of tectonism associated with the development of the Neogene Lesser Antilles arc on an older arc system.

  3. Ancient buried submarine trough, northwest Gulf of Mexico

    USGS Publications Warehouse

    Berryhill, H.L., Jr.

    1981-01-01

    A large buried submarine trough crosses the seaward margin of the continental shelf off the southwest coast of Louisiana. Original length was about 90 km, and width at the shelf edge was 16 km. Maximum eroded depth may have been as much as 305 m. Seismic characteristics of the prograded fill indicate cyclically repeated sequences of retrogressive deltaic and partly slumped sediments overlain by well-layered transgressive deposits. Slumping was increasingly prevalent toward the shelf edge. The cyclic sequences indicate that the trough was a passageway for large volumes of sediment onto the continental slope during several stages of lowered sea level. ?? 1981 A.M. Dowden, Inc.

  4. Stable parabolic Higgs bundles as asymptotically stable decorated swamps

    NASA Astrophysics Data System (ADS)

    Beck, Nikolai

    2016-06-01

    Parabolic Higgs bundles can be described in terms of decorated swamps, which we studied in a recent paper. This description induces a notion of stability of parabolic Higgs bundles depending on a parameter, and we construct their moduli space inside the moduli space of decorated swamps. We then introduce asymptotic stability of decorated swamps in order to study the behaviour of the stability condition as one parameter approaches infinity. The main result is the existence of a constant, such that stability with respect to parameters greater than this constant is equivalent to asymptotic stability. This implies boundedness of all decorated swamps which are semistable with respect to some parameter. Finally, we recover the usual stability condition of parabolic Higgs bundles as asymptotic stability.

  5. Localized spin wave modes in parabolic field wells

    NASA Astrophysics Data System (ADS)

    McMichael, Robert; Tartakovskaya, Elena; Pardavi-Horvath, Martha

    We describe spin wave modes trapped in parabolic-profile field wells. Trapped spin waves can be used as local probes of magnetic properties with resolution down to 100 nm in ferromagnetic resonance force microscopy. Localized modes have been shown to form around field minima from a number of sources, including stray fields from magnetic probe tips and inhomogeneous magnetostatic fields near film edges. Here, we address the most basic trap, which is a parabolic minimum in the applied field. The magnetic eigenmodes in this trap are tractable enough to serve as approximations in more realistic situations. For a parabolic field, we select basis mode profiles proportional to Hermite functions because they are eigenfuctions of the applied field and exchange parts of the equations of motion. Additionally, we find that these Hermite modes are approximate eigenfunctions of magnetostatic interactions, showing good agreement with micromagnetic calculations. More precise agreement is achieved by diagonalizing the equations of motion using only a few modes.

  6. Anisotropic electromagnetic wave propagation modeling using parabolic approximations

    NASA Astrophysics Data System (ADS)

    Brent, R. I.; Siegmann, W. L.; Jacobson, M. J.; Jacyna, G. M.

    1990-12-01

    A new method for the investigation of anisotropic electromagnetic wave propagation in the atmosphere is developed using parabolic approximations. Model equations for the electric field components are formulated which include the effects of both the inhomogeneous atmosphere and the static magnetic field of the earth. Application of parabolic-type approximations produces different systems of coupled parabolic equations. Each is valid for different relative magnitudes of components of the electric field. All admissible cases are then synthesized into one system which can be numerically examined, yielding solutions without a priori knowledge of electric field ratios. A specific example is presented and examined to understand static magnetic field effects on electromagnetic wave propagation. The influences of the earth's magnetic field are discussed and displayed in terms of electric components and the Poynting vector. Results demonstrate that the geomagnetic field can significantly influence HF atmospheric propagation.

  7. Deep-water hydrocarbon potential of Georges Bank Trough

    SciTech Connect

    Levie, D.S. Jr.

    1985-02-01

    Characterization of the petroleum potential for Georges Bank Trough has been based primarily on limited organic geochemical data that indicate the area of recent drilling activity behind the paleoshelf edge to be poor in organic carbon and C/sub 15/ + extract values, with predominantly terrestrial kerogen types. Maturation data also suggest an inadequate thermal history for hydrocarbon generation in the area. It is possible that the effects of heat flow from the New England Seamount Chain may contribute to hydrocarbon generation in the Georges Bank Trough - a relationship that may also exist between the Newfoundland Seamount Chain and the Hibernia area of the Grand Banks. Also, comparisons can be drawn between the Atlantic Fracture Zone bordering the Georges Bank Trough and the Romanche-St. Paul Fracture Zone off the Ivory Coast. In the latter region, restricted anoxic environments with sediments rich in marine kerogen types have been identified, as have both structural and stratigraphic trapping mechanisms. Within this rhombochasm configuration, reservoir lithologies of sandstone and carbonate turbidites, fractured deep-water chalks, and reefal limestones should occur. The relationships of seamount to fracture zone, as applied to the rhombochasm model for the Georges Bank Trough, should enhance the hydrocarbon potential of the lower Mesozoic sediments seaward of the paleoshelf edge and thus classify this area as a future major hydrocarbon province.

  8. Electrodynamic structure of the morning high-latitude trough region

    NASA Astrophysics Data System (ADS)

    Vanhamäki, H.; Aikio, A.; Voiculescu, M.; Juusola, L.; Nygrén, T.; Kuula, R.

    2016-03-01

    We describe the electrodynamics of a postmidnight, high-latitude ionospheric trough, observed with the European Incoherent Scatter radar in northern Scandinavia on 24-25 June 2003 around 22:00-02:30 UT during quiet conditions. The UHF radar made meridian scans with a 30 min cadence resulting in nine cross sections of ionospheric parameters. The F region electric field was also determined with the tristatic system. Ionospheric equivalent currents, calculated from ground magnetometer data, mostly show an electrojet-like current that is reasonably uniform in the longitudinal direction. Combined analysis of the conductances and equivalent current with a local Kamide-Richmond-Matsushita (KRM) method yields the ionospheric electric field and field-aligned current (FAC) in a 2-D (latitude-longitude) area around the radar. We conclude that the most likely scenario is one where the trough is initially created poleward of the auroral oval by downward FAC that evacuates the F region, but as the trough moves to lower latitudes during the early morning hours, it becomes colocated with the westward electrojet. There the electron density further decreases due to increased recombination caused by enhanced ion temperature, which in turn is brought about by a larger convection speed. Later in the morning the convection speed decreases and the trough is filled by increasing photoionization.

  9. Identification of Risk Factors for Elevated Neonatal Gentamicin Trough Concentrations

    PubMed Central

    Ahern, John; Noyes, Elizabeth; Corriveau, Michele; Mercier, Charles

    2016-01-01

    OBJECTIVES: The objective of this study was to identify neonatal and maternal characteristics that may be associated with elevated neonatal gentamicin trough concentrations despite application of a previously published gentamicin dosage strategy. METHODS: Retrospective cohort study of all neonates admitted to University of Vermont Medical Center (562-bed academic teaching hospital, Burlington, VT) receiving gentamicin between June 1, 2009, and August 31, 2013. A total of 205 neonates were included, with 41 cases and 164 controls. RESULTS: Postmenstrual age (PMA, gestational age plus chronological age) and small-for–gestational age (SGA) status were independently associated with elevated neonatal gentamicin trough concentrations. No maternal risk factor evaluated remained significantly associated in the multivariate analysis. CONCLUSIONS: The probability of an elevated gentamicin trough concentration increases with lower PMA and is further accentuated in neonates with SGA status. In contrast, the presence of maternal risk factors did not increase the likelihood of elevated gentamicin trough concentrations. Neonates with lower PMA and SGA status may require an individualized dosage and monitoring strategy. PMID:27199620

  10. Strawberry Production in Soilless Substrate Troughs – Plant Growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soilless substrates made of peat moss, coconut coir, perlite, rockwool or bark are pathogen free and they have been used in strawberry production in Europe in troughs or containers. Open field strawberry production in soilless substrate is new to California growers. The objective of this study was t...

  11. 3. WOODLINED TROUGH WITH AQUEDUCT WASTE GATES IN THE OPEN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. WOOD-LINED TROUGH WITH AQUEDUCT WASTE GATES IN THE OPEN POSITION, LOOKING NORTH. TRANSVERSE GIRDERS HAVE BEEN ADDED TO HELP STABILIZE THE AQUEDUCT. - Ohio & Erie Canal, Tinker's Creek Aqueduct, Canal Road, South Tinkers Creek Road, Valley View, Cuyahoga County, OH

  12. Parabolic approximation method for fast magnetosonic wave propagation in tokamaks

    SciTech Connect

    Phillips, C.K.; Perkins, F.W.; Hwang, D.Q.

    1985-07-01

    Fast magnetosonic wave propagation in a cylindrical tokamak model is studied using a parabolic approximation method in which poloidal variations of the wave field are considered weak in comparison to the radial variations. Diffraction effects, which are ignored by ray tracing mthods, are included self-consistently using the parabolic method since continuous representations for the wave electromagnetic fields are computed directly. Numerical results are presented which illustrate the cylindrical convergence of the launched waves into a diffraction-limited focal spot on the cyclotron absorption layer near the magnetic axis for a wide range of plasma confinement parameters.

  13. Focusing of Intense Laser via Parabolic Plasma Concave Surface

    NASA Astrophysics Data System (ADS)

    Zhou, Weimin; Gu, Yuqiu; Wu, Fengjuan; Zhang, Zhimeng; Shan, Lianqiang; Cao, Leifeng; Zhang, Baohan

    2015-12-01

    Since laser intensity plays an important role in laser plasma interactions, a method of increasing laser intensity - focusing of an intense laser via a parabolic plasma concave surface - is proposed and investigated by three-dimensional particle-in-cell simulations. The geometric focusing via a parabolic concave surface and the temporal compression of high harmonics increased the peak intensity of the laser pulse by about two orders of magnitude. Compared with the improvement via laser optics approaches, this scheme is much more economic and appropriate for most femtosecond laser facilities. supported by National Natural Science Foundation of China (Nos. 11174259, 11175165), and the Dual Hundred Foundation of China Academy of Engineering Physics

  14. Extension of Euler’s method to parabolic equations

    NASA Astrophysics Data System (ADS)

    Ibragimov, N. H.

    2009-04-01

    Euler generalized d'Alembert's solution to a wide class of linear hyperbolic equations with two independent variables. He introduced in 1769 the quantities that were rediscovered by Laplace in 1773 and became known as the Laplace invariants. The present paper is devoted to an extension of Euler's method to linear parabolic equations with two independent variables. The new method allows one to derive an explicit formula for the general solution of a wide class of parabolic equations. In particular, the general solution of the Black-Scholes equation is obtained.

  15. European parabolic flight campaigns with Airbus ZERO-G: Looking back at the A300 and looking forward to the A310

    NASA Astrophysics Data System (ADS)

    Pletser, Vladimir; Rouquette, Sebastien; Friedrich, Ulrike; Clervoy, Jean-Francois; Gharib, Thierry; Gai, Frederic; Mora, Christophe

    2015-09-01

    Aircraft parabolic flights repetitively provide up to 23 s of reduced gravity during ballistic flight manoeuvres. Parabolic flights are used to conduct short microgravity investigations in Physical and Life Sciences and in Technology, to test instrumentation prior to space flights and to train astronauts before a space mission. The use of parabolic flights is complementary to other microgravity carriers (drop towers, sounding rockets), and preparatory to manned space missions on board the International Space Station and other manned spacecraft, such as Shenzhou and the Chinese Space Station CSS. The European Space Agency (ESA), the 'Centre National d'Etudes Spatiales' (CNES, French Space Agency) and the 'Deutsches Zentrum für Luft- und Raumfahrt e.V.' (DLR, the German Aerospace Centre) have used the Airbus A300 ZERO-G for research experiments in microgravity, and at Moon and Mars gravity levels, from 1997 until October 2014. The French company Novespace, a subsidiary of CNES, based in Bordeaux, France, is in charge of the organisation of Airbus A300 ZERO-G flights. A total of 104 parabolic flight campaigns have been organised by ESA, CNES and DLR since 1997, including 38 ESA, 34 CNES and 23 DLR microgravity campaigns, two Joint European ESA-CNES-DLR Partial-g Parabolic Flight Campaigns, and seven ESA Student campaigns. After 17 years of good and loyal services, this European workhorse for microgravity research in parabolic flights has been retired. The successor aircraft, the Airbus A310 ZERO-G, is being prepared for a first ESA-CNES-DLR cooperative campaign in Spring 2015. This paper looks back over 17 years of microgravity research in parabolic flights with the A300 ZERO-G, and introduces the new A310 ZERO-G that will be used from 2015 onwards.

  16. Global existence of weak solutions to quasilinear degenerate Keller-Segel systems of parabolic-parabolic type

    NASA Astrophysics Data System (ADS)

    Ishida, Sachiko; Yokota, Tomomi

    This paper deals with the quasilinear degenerate Keller-Segel system (KS) of parabolic-parabolic type. The global existence of weak solutions to (KS) is established when q

  17. A long-term strategic plan for development of solar thermal electric technology

    SciTech Connect

    Williams, T.A.; Burch, G.D.; Chavez, J.M.; Mancini, T.R.; Tyner, C.E.

    1997-06-01

    Solar thermal electric (STE) technologies--parabolic troughs, power towers, and dish/engine systems--can convert sunlight into electricity efficiently and with minimum effect on the environment. These technologies currently range from developmental to early commercial stages of maturity. This paper summarizes the results of a recent strategic planning effort conducted by the US Department of Energy (DOE) to develop a long-term strategy for the development of STE technologies (DOE, 1996). The planning team led by DOE included representatives from the solar thermal industry, domestic utilities, state energy offices, and Sun-Lab (the cooperative Sandia National Laboratories/National Renewable Energy Laboratory partnership that supports the STE Program) as well as project developers. The plan was aimed at identifying specific activities necessary to achieve the DOE vision of 20 gigawatts of installed STE capacity by the year 2020. The planning team developed five strategies that both build on the strengths of, and opportunities for, STE technology and address weaknesses and threats. These strategies are to support future commercial opportunities for STE technologies; demonstrate improved performance and reliability of STE components and systems; reduce STE energy costs; develop advanced STE systems and applications; and address nontechnical barriers and champion STE power. The details of each of these strategies are discussed.

  18. A long-term strategic plan for development of solar thermal electric technology

    SciTech Connect

    Williams, T.A.; Burch, G.; Chavez, J.M.; Mancini, T.R.; Tyner, C.E.

    1997-06-01

    Solar thermal electric (STE) technologies--parabolic troughs, power towers, and dish/engine systems--can convert sunlight into electricity efficiently and with minimum effect on the environment. These technologies currently range from developmental to early commercial stages of maturity. This paper summarizes the results of a recent strategic planning effort conducted by the US department of Energy (DOE) to develop a long-term strategy for the development of STE technologies. The planning team led by DOE included representatives from the solar thermal industry, domestic utilities, state energy offices, and Sun{center_dot}Lab (the cooperative Sandia National laboratories/National Renewable Energy Laboratory partnership that supports the STE Program) as well as project developers. The plan was aimed at identifying specific activities necessary to achieve the DOE vision of 20 gigawatts of installed STE capability by the year 2020. The planning team developed five strategies that both build on the strengths of, and opportunities for, STE technology and address weaknesses and threats. These strategies are to: support future commercial opportunities for STE technologies; demonstrate improved performance and reliability of STE components and systems; reduce STE energy costs; develop advanced STE systems and applications; and address nontechnical barriers and champion STE power. The details of each of these strategies are discussed.

  19. Orthostatic intolerance and motion sickness after parabolic flight

    NASA Technical Reports Server (NTRS)

    Schlegel, T. T.; Brown, T. E.; Wood, S. J.; Benavides, E. W.; Bondar, R. L.; Stein, F.; Moradshahi, P.; Harm, D. L.; Fritsch-Yelle, J. M.; Low, P. A.

    2001-01-01

    Because it is not clear that the induction of orthostatic intolerance in returning astronauts always requires prolonged exposure to microgravity, we investigated orthostatic tolerance and autonomic cardiovascular function in 16 healthy subjects before and after the brief micro- and hypergravity of parabolic flight. Concomitantly, we investigated the effect of parabolic flight-induced vomiting on orthostatic tolerance, R-wave-R-wave interval and arterial pressure power spectra, and carotid-cardiac baroreflex and Valsalva responses. After parabolic flight 1) 8 of 16 subjects could not tolerate 30 min of upright tilt (compared to 2 of 16 before flight); 2) 6 of 16 subjects vomited; 3) new intolerance to upright tilt was associated with exaggerated falls in total peripheral resistance, whereas vomiting was associated with increased R-wave-R-wave interval variability and carotid-cardiac baroreflex responsiveness; and 4) the proximate mode of new orthostatic failure differed in subjects who did and did not vomit, with vomiters experiencing comparatively isolated upright hypocapnia and cerebral vasoconstriction and nonvomiters experiencing signs and symptoms reminiscent of the clinical postural tachycardia syndrome. Results suggest, first, that syndromes of orthostatic intolerance resembling those developing after space flight can develop after a brief (i.e., 2-h) parabolic flight and, second, that recent vomiting can influence the results of tests of autonomic cardiovascular function commonly utilized in returning astronauts.

  20. The dynamics of parabolic flight: flight characteristics and passenger percepts.

    PubMed

    Karmali, Faisal; Shelhamer, Mark

    2008-09-01

    Flying a parabolic trajectory in an aircraft is one of the few ways to create freefall on Earth, which is important for astronaut training and scientific research. Here we review the physics underlying parabolic flight, explain the resulting flight dynamics, and describe several counterintuitive findings, which we corroborate using experimental data. Typically, the aircraft flies parabolic arcs that produce approximately 25 seconds of freefall (0 g) followed by 40 seconds of enhanced force (1.8 g), repeated 30-60 times. Although passengers perceive gravity to be zero, in actuality acceleration, and not gravity, has changed, and thus we caution against the terms "microgravity" and "zero gravity. " Despite the aircraft trajectory including large (45°) pitch-up and pitch-down attitudes, the occupants experience a net force perpendicular to the floor of the aircraft. This is because the aircraft generates appropriate lift and thrust to produce the desired vertical and longitudinal accelerations, respectively, although we measured moderate (0.2 g) aft-ward accelerations during certain parts of these trajectories. Aircraft pitch rotation (average 3°/s) is barely detectable by the vestibular system, but could influence some physics experiments. Investigators should consider such details in the planning, analysis, and interpretation of parabolic-flight experiments. PMID:19727328

  1. The dynamics of parabolic flight: Flight characteristics and passenger percepts

    NASA Astrophysics Data System (ADS)

    Karmali, Faisal; Shelhamer, Mark

    2008-09-01

    Flying a parabolic trajectory in an aircraft is one of the few ways to create freefall on Earth, which is important for astronaut training and scientific research. Here we review the physics underlying parabolic flight, explain the resulting flight dynamics, and describe several counterintuitive findings, which we corroborate using experimental data. Typically, the aircraft flies parabolic arcs that produce approximately 25 s of freefall (0 g) followed by 40 s of enhanced force (1.8 g), repeated 30-60 times. Although passengers perceive gravity to be zero, in actuality acceleration, and not gravity, has changed, and thus we caution against the terms "microgravity" and "zero gravity." Despite the aircraft trajectory including large (45°) pitch-up and pitch-down attitudes, the occupants experience a net force perpendicular to the floor of the aircraft. This is because the aircraft generates appropriate lift and thrust to produce the desired vertical and longitudinal accelerations, respectively, although we measured moderate (0.2 g) aft-ward accelerations during certain parts of these trajectories. Aircraft pitch rotation (average 3°/s) is barely detectable by the vestibular system, but could influence some physics experiments. Investigators should consider such details in the planning, analysis, and interpretation of parabolic-flight experiments.

  2. Anisotropic uniqueness classes for a degenerate parabolic equation

    SciTech Connect

    Vil'danova, V F; Mukminov, F Kh

    2013-11-30

    Anisotropic uniqueness classes of Tacklind type are identified for a degenerate linear parabolic equation of the second order in an unbounded domain. The Cauchy problem and mixed problems with boundary conditions of the first and third type are considered. Bibliography: 18 titles.

  3. Lateral migration of a capsule in a parabolic flow.

    PubMed

    Nix, S; Imai, Y; Ishikawa, T

    2016-07-26

    Red blood cells migrate to the center of the blood vessel in a process called axial migration, while other blood cells, such as white blood cells and platelets, are disproportionately found near the blood vessel wall. However, much is still unknown concerning the lateral migration of cells in the blood; the specific effect of hydrodynamic factors such as a wall or a shear gradient is still unclear. In this study, we investigate the lateral migration of a capsule using the boundary integral method, in order to compute exactly an infinite computational domain for an unbounded parabolic flow and a semi-infinite computational domain for a near-wall parabolic flow in the limit of Stokes flow. We show that the capsule lift velocity in an unbounded parabolic flow is linear with respect to the shear gradient, while the lift velocity in a near-wall parabolic flow is dependent on the distance to the wall. Then, using these relations, we give an estimation of the relative effect of the shear gradient as a function of channel width and distance between the capsule and the wall. This estimation can be used to determine cases in which the effect of the shear gradient or wall can be neglected; for example, the formation of the cell-free layer in blood vessels is determined to be unaffected by the magnitude of the shear gradient. PMID:26674473

  4. Orthostatic intolerance and motion sickness after parabolic flight.

    PubMed

    Schlegel, T T; Brown, T E; Wood, S J; Benavides, E W; Bondar, R L; Stein, F; Moradshahi, P; Harm, D L; Fritsch-Yelle, J M; Low, P A

    2001-01-01

    Because it is not clear that the induction of orthostatic intolerance in returning astronauts always requires prolonged exposure to microgravity, we investigated orthostatic tolerance and autonomic cardiovascular function in 16 healthy subjects before and after the brief micro- and hypergravity of parabolic flight. Concomitantly, we investigated the effect of parabolic flight-induced vomiting on orthostatic tolerance, R-wave-R-wave interval and arterial pressure power spectra, and carotid-cardiac baroreflex and Valsalva responses. After parabolic flight 1) 8 of 16 subjects could not tolerate 30 min of upright tilt (compared to 2 of 16 before flight); 2) 6 of 16 subjects vomited; 3) new intolerance to upright tilt was associated with exaggerated falls in total peripheral resistance, whereas vomiting was associated with increased R-wave-R-wave interval variability and carotid-cardiac baroreflex responsiveness; and 4) the proximate mode of new orthostatic failure differed in subjects who did and did not vomit, with vomiters experiencing comparatively isolated upright hypocapnia and cerebral vasoconstriction and nonvomiters experiencing signs and symptoms reminiscent of the clinical postural tachycardia syndrome. Results suggest, first, that syndromes of orthostatic intolerance resembling those developing after space flight can develop after a brief (i.e., 2-h) parabolic flight and, second, that recent vomiting can influence the results of tests of autonomic cardiovascular function commonly utilized in returning astronauts. PMID:11133895

  5. Finite-difference methods for solving loaded parabolic equations

    NASA Astrophysics Data System (ADS)

    Abdullayev, V. M.; Aida-zade, K. R.

    2016-01-01

    Loaded partial differential equations are solved numerically. For illustrative purposes, a boundary value problem for a parabolic equation with various point loads is considered. By applying difference approximations, the problems are reduced to systems of algebraic equations of special structure, which are solved using a parametric representation involving solutions of auxiliary linear systems with tridiagonal matrices. Numerical results are presented and analyzed.

  6. Compound parabolic concentrator with cavity for tubular absorbers

    DOEpatents

    Winston, Roland

    1983-01-01

    A compond parabolic concentrator with a V-shaped cavity is provided in which an optical receiver is emplaced. The cavity redirects all energy entering between the receiver and the cavity structure onto the receiver, if the optical receiver is emplaced a distance from the cavity not greater than 0.27 r (where r is the radius of the receiver).

  7. The dynamics of parabolic flight: flight characteristics and passenger percepts

    PubMed Central

    Karmali, Faisal; Shelhamer, Mark

    2008-01-01

    Flying a parabolic trajectory in an aircraft is one of the few ways to create freefall on Earth, which is important for astronaut training and scientific research. Here we review the physics underlying parabolic flight, explain the resulting flight dynamics, and describe several counterintuitive findings, which we corroborate using experimental data. Typically, the aircraft flies parabolic arcs that produce approximately 25 seconds of freefall (0 g) followed by 40 seconds of enhanced force (1.8 g), repeated 30–60 times. Although passengers perceive gravity to be zero, in actuality acceleration, and not gravity, has changed, and thus we caution against the terms "microgravity" and "zero gravity. " Despite the aircraft trajectory including large (45°) pitch-up and pitch-down attitudes, the occupants experience a net force perpendicular to the floor of the aircraft. This is because the aircraft generates appropriate lift and thrust to produce the desired vertical and longitudinal accelerations, respectively, although we measured moderate (0.2 g) aft-ward accelerations during certain parts of these trajectories. Aircraft pitch rotation (average 3°/s) is barely detectable by the vestibular system, but could influence some physics experiments. Investigators should consider such details in the planning, analysis, and interpretation of parabolic-flight experiments. PMID:19727328

  8. Boundary control of parabolic systems - Finite-element approximation

    NASA Technical Reports Server (NTRS)

    Lasiecka, I.

    1980-01-01

    The finite element approximation of a Dirichlet type boundary control problem for parabolic systems is considered. An approach based on the direct approximation of an input-output semigroup formula is applied. Error estimates are derived for optimal state and optimal control, and it is noted that these estimates are actually optimal with respect to the approximation theoretic properties.

  9. Spherical harmonics approach to parabolic partial differential equations

    NASA Astrophysics Data System (ADS)

    SenGupta, Indranil; Mariani, Maria C.

    2012-12-01

    This paper is devoted to extend the spherical harmonics technique to the solution of parabolic differential equations and to integro-differential equations. The heat equation and the Black-Scholes equation are solved by using the method of spherical harmonics.

  10. Orthostatic Intolerance and Motion Sickness After Parabolic Flight

    NASA Technical Reports Server (NTRS)

    Schlegel, Todd T.; Brown, Troy E.; Wood, Scott J.; Benavides, Edgar W.; Bondar, Roberta L.; Stein, Flo; Moradshahi, Peyman; Harm, Deborah L.; Low, Phillip A.

    1999-01-01

    Orthostatic intolerance is common in astronauts after prolonged space flight. However, the "push-pull effect" in military aviators suggests that brief exposures to transitions between hypo- and hypergravity are sufficient to induce untoward autonomic cardiovascular physiology in susceptible individuals. We therefore investigated orthostatic tolerance and autonomic cardiovascular function in 16 healthy test subjects before and after a seated 2-hr parabolic flight. At the same time, we also investigated relationships between parabolic flight-induced vomiting and changes in orthostatic and autonomic cardiovascular function. After parabolic flight, 8 of 16 subjects could not tolerate a 30-min upright tilt test, compared to 2 of 16 before flight. Whereas new intolerance in non-Vomiters resembled the clinical postural tachycardia syndrome (POTS), new intolerance in Vomiters was characterized by comparatively isolated upright hypocapnia and cerebral vasoconstriction. As a group, Vomiters also had evidence for increased postflight fluctuations in efferent vagal-cardiac nerve traffic occurring independently of any superimposed change in respiration. Results suggest that syndromes of orthostatic intolerance resembling those occurring after space flight can occur after a brief (i.e., 2-hr) parabolic flight.

  11. A Parabolic Problem with a Fractional Time Derivative

    NASA Astrophysics Data System (ADS)

    Allen, Mark; Caffarelli, Luis; Vasseur, Alexis

    2016-08-01

    We study regularity for a parabolic problem with fractional diffusion in space and a fractional time derivative. Our main result is a De Giorgi-Nash-Moser Hölder regularity theorem for solutions in a divergence form equation. We also prove results regarding existence, uniqueness, and higher regularity in time.

  12. 3X compound parabolic concentrating (CPC) solar energy collector. Final technical report

    SciTech Connect

    Ballheim, R.W.

    1980-04-25

    Chamberlain engineers designed a 3X compound parabolic concentrating (CPC) collector for the subject contract. The collector is a completely housed, 105.75 x 44.75 x 10.23-inch, 240-pound unit with six each evacuated receiver assemblies, a center manifold and a one-piece glass cover. A truncated version of a CPC trough reflector system and the General Electric Company tubular evacuated receiver have been integrated with a mass producible collector design suitable for operation at 250 to 450/sup 0/F. The key criterion for optimization of the design was minimization of the cost per Btu collected annually at an operating temperature of 400/sup 0/F. The reflector is a 4.1X design truncated to a total height of 8.0 inches with a resulting actual concentration ratio of 2.6 to 1. The manifold is an insulated area housing the fluid lines which connect the six receivers in series with inlet and outlet tubes extending from one side of the collector at the center. The reflectors are polished, anodized aluminum which are shaped by the roll form process. The housing is painted, galvanized steel, and the cover glass is 3/16-inch thick tempered, low iron glass. The collector requires four slope adjustments per year for optimum effectiveness. Chamberlain produced ten 3X CPC collectors for the subject contract. Two collectors were used to evaluate assembly procedures, six were sent to the project officer in Albuquerque, New Mexico, one was sent to Argonne National Laboratory for performance testing and one remained with the Company. A manufacturing cost study was conducted to estimate limited mass production costs, explore cost reduction ideas and define tooling requirements. The final effort discussed shows the preliminary design for application of a 3X CPC solar collector system for use in the Iowa State Capitol complex.

  13. IR Spectrometer Using 90-Degree Off-Axis Parabolic Mirrors

    SciTech Connect

    Robert M. Malone, Ian J. McKenna

    2008-03-01

    A gated spectrometer has been designed for real-time, pulsed infrared (IR) studies at the National Synchrotron Light Source at the Brookhaven National Laboratory. A pair of 90-degree, off-axis parabolic mirrors are used to relay the light from an entrance slit to an output recording camera. With an initial wavelength range of 1500–4500 nm required, gratings could not be used in the spectrometer because grating orders would overlap. A magnesium oxide prism, placed between these parabolic mirrors, serves as the dispersion element. The spectrometer is doubly telecentric. With proper choice of the air spacing between the prism and the second parabolic mirror, any spectral region of interest within the InSb camera array’s sensitivity region can be recorded. The wavelengths leaving the second parabolic mirror are collimated, thereby relaxing the camera positioning tolerance. To set up the instrument, two different wavelength (visible) lasers are introduced at the entrance slit and made collinear with the optical axis via flip mirrors. After dispersion by the prism, these two laser beams are directed to tick marks located on the outside housing of the gated IR camera. This provides first-order wavelength calibration for the instrument. Light that is reflected off the front prism face is coupled into a high-speed detector to verify steady radiance during the gated spectral imaging. Alignment features include tick marks on the prism and parabolic mirrors. This instrument was designed to complement single-point pyrometry, which provides continuous time histories of a small collection of spots from shock-heated targets.

  14. IR Spectrometer Using 90-degree Off-axis Parabolic Mirrors

    SciTech Connect

    Robert M. Malone, Richard, G. Hacking, Ian J. McKenna, and Daniel H. Dolan

    2008-09-02

    A gated spectrometer has been designed for real-time, pulsed infrared (IR) studies at the National Synchrotron Light ource at the Brookhaven National Laboratory. A pair of 90-degree, off-axis parabolic mirrors are used to relay the light from an entrance slit to an output IR recording camera. With an initial wavelength range of 1500–4500 nm required, gratings could not be used in the spectrometer because grating orders would overlap. A magnesium oxide prism, placed between these parabolic mirrors, serves as the dispersion element. The spectrometer is doubly telecentric. With proper choice of the air spacing between the prism and the second parabolic mirror, any spectral region of interest within the InSb camera array’s sensitivity region can be recorded. The wavelengths leaving the second parabolic mirror are collimated, thereby relaxing the camera positioning tolerance. To set up the instrument, two different wavelength (visible) lasers are introduced at the entrance slit and made collinear with the optical axis via flip mirrors. After dispersion by the prism, these two laser beams are directed to tick marks located on the outside housing of the gated IR camera. This provides first-order wavelength calibration for the instrument. Light that is reflected off the front prism face is coupled into a high-speed detector to verify steady radiance during the gated spectral imaging. Alignment features include tick marks on the prism and parabolic mirrors. This instrument was designed to complement singlepoint pyrometry, which provides continuous time histories of a small collection of spots from shock-heated targets.

  15. The Rome trough and evolution of the Iapetean margin

    SciTech Connect

    Walker, D.; Hamilton-Smith, T.; Drahovzal, J.A. )

    1991-08-01

    Recent structural mapping of the Rome trough suggests a complex structure very different from the symmetrical and laterally continuous graben commonly depicted. Early and Middle Cambrian extension in the Rome trough of eastern Kentucky and adjacent areas resulted in a series of alternately facing half-grabens with variable displacement. These half-grabens are bounded by southwest-northeast-trending normal faults (e.g., Kentucky River and Warfield faults), which are laterally continuous only on the order to tens of kilometers. The Rome trough is laterally segmented by north-south-trending faults (e.g., Lexington fault) commonly expressed as flexures in younger rocks (e.g., Burning Springs anticline and Floyd County channel). Many of these north-south-trending faults have significant left-lateral displacement, and probably represent reactivated thrust faults of the Grenville tectonic front. The Rome trough and the associated Mississippi Valley, Rough Creek, and Birmingham fault systems were initiated during an Early Cambrian shift in sea-floor spreading from the Blue Ridge-Pine Mountain rift to the Ouachita rift along the Alabama-Oklahoma transform fault. These fault systems have been proposed as having originated from extensional stress propagated northward from the Ouachita rift across the transform fault. In the alternate model proposed here, faulting was brittle, extensional failure resulting form subsidence and flexure of the continental margin to the east. Following initiation of sea-floor spreading at the Blue Ridge-Pine Mountain rift in the latest Proterozoic, margin subsidence in the presence of the Alabama-Oklahoma transform boundary and the inherited Grenville tectonic front resulted in this interior cratonic fault system.

  16. Detecting Strain Transients in the Salton Trough (Invited)

    NASA Astrophysics Data System (ADS)

    McGuire, J. J.; Segall, P.; Herring, T.

    2009-12-01

    The Salton Trough region routinely experiences fault creep transients with time-scales of days to weeks, and previous studies have documented a temporal relationship between these aseimsic transients and earthquake swarms. The Plate Boundary Observatory has greatly increased the density of continuous geodetic data available in the Salton Trough, and we are analyzing this dataset to detect time periods when aseismic transients occurred in the Salton Trough. We are searching the daily GPS solutions for the time period from 2005-2009 for transients using Kalman Filter based detection algorithm called the Network Strain Filter [Ohtani, McGuire, and Segall, 2009]. The NSF solves for estimates of the secular velocity field and a time-vary transient displacement field that are expanded in basis functions. We utilize two dimensional wavelets as the basis functions. Spatial smoothing of the transient and secular velocity field are achieved by weighting the prior covariance matrix elements based on the scale of the individual wavelet basis. Site specific colored noise (seasonal terms, etc) is estimated as an random walk for each component. The vast majority of the Salton Trough GPS records are well explained by a combination of secular velocity and seasonal terms. However, we do find two spatially coherent transient episodes visible at multiple stations in the GPS data. The largest occurs near the southern extension of the Superstition Hills fault (Weinert Fault) during the second half of 2007. About 1 cm of extra motion to the northwest is observed at station P494, P496, and P497. The time scale of this transient is a few months. A second, smaller more abrupt transient is observed at stations P500 and P744 at the time of the February 2008 earthquake swarm at Cerro Prieto. We are investigating whether these two transients can be explained by slip on the Superstition Hills and Imperial faults respectively.

  17. DETAIL VIEW OF CLASSIFIER, TAILINGS LAUNDER TROUGH, LINE SHAFTS, AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF CLASSIFIER, TAILINGS LAUNDER TROUGH, LINE SHAFTS, AND CONCENTRATION TABLES, LOOKING SOUTHWEST. SLURRY EXITING THE BALL MILL WAS COLLECTED IN AN AMALGAMATION BOX (MISSING) FROM THE END OF THE MILL, AND INTRODUCED INTO THE CLASSIFIER. THE TAILINGS LAUDER IS ON THE GROUND AT LOWER RIGHT. THE LINE SHAFTING ABOVE PROVIDED POWER TO THE CONCENTRATION TABLES BELOW AT CENTER RIGHT. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

  18. Concept of Methane Hydrate System in the eastern Nankai Trough

    NASA Astrophysics Data System (ADS)

    Nagakubo, S.; Fujii, T.; Noguchi, S.; Kawasaki, T.

    2008-12-01

    By the study of the Phase 1 (FY2001-2008) of the Research Consortium for Methane Hydrate Resources in Japan (MH21 Research Consortium), MH21 Research Consortium showed that methane hydrates pore-filled in sandy sediments had a potential to develop in the future. It is important to clarify the accumulation mechanism and processes of methane hydrates pore-filled in sandy sediment because it would contribute to explore new methane hydrate field to develop other than the eastern Nankai Trough in the future. Therefore Japan Oil, Gas and Metals National Corporation (JOGMEC), as a member of MH21 Research Consortium, has been constructing a concept of Methane Hydrate System (methane generation and migration, MH formation and dissociation) with methane hydrates pore-filled in sandy sediment. We extracted critical elements and executed processes to summarize Methane Hydrate System in the eastern Nankai Trough by reviewing past geochemical analysis, well logs and core analyses, seismic interpretations, and laboratory studies for the eastern Nankai Trough. We also conducted case studies using 1D and 2D numerical simulators developed for the clarification of methane hydrate accumulation mechanism. It was determined that there are still many unsolved issues as listed below though we try to construct a concept of Methane Hydrate System in the eastern Nankai Trough. 1.Methane source and migration -methane-dominant generation depth -methane generation rate. -driving forces of methane migration 2.Occurrences and distribution -occurrences and distribution of methane hydrates other than methane hydrates pore-filled in sandy sediment. -methane-bearing fluid condition (properties, distribution) below methane hydrate bearing zones. 3.Relation between seafloor phenomena and methane hydrate occurences. 4.Impact of geohistory and sea level (water depth) change to methane hydrate accumulation. New investigation surveys (drilling and geological/geochemical surveys on seafloor) are required to

  19. Grounding zone wedges, Kveithola Trough (NW Barents Sea)

    NASA Astrophysics Data System (ADS)

    Rebesco, Michele; Urgeles, Roger; Özmaral, Asli; Hanebuth, Till; Caburlotto, Andrea; Hörner, Tanja; Lantzsch, Hendrik; LLopart, Juame; Lucchi, Renata; Skøtt Nicolaisen, Line; Giacomo, Osti; Sabbatini, Anna; Camerlenghi, Angelo

    2014-05-01

    Swath bathymetry within Kveithola Trough (NW Barents Sea) shows a seafloor characterized by E-W trending megascale glacial lineations (MSGLs) overprinted by transverse Grounding Zone Wedges (GZWs), which give the trough a stair profile (Rebesco et al., 2011). GZWs are formed by deposition of subglacial till at temporarily stable ice-stream fronts in between successive episodic retreats (Rüther et al., 2012; Bjarnadóttir et al., 2012). Sub-bottom data show that present-day morphology is largely inherited from palaeo-seafloor topography of GZWs, which is draped by a deglacial to early Holocene glaciomarine sediments (about 15 m thick). The ice stream that produced such subglacial morphology was flowing from East to West inside Kveithola Trough during Last Glacial Maximum. Its rapid retreat was likely associated with progressive lift-offs, and successive rapid melting of the grounded ice, induced by the eustatic sea-level rise (Lucchi et al., 2013). References: Bjarnadóttir, L.R., Rüther, D.C., Winsborrow, M.C.M., Andreassen, K., 2012. Grounding-line dynamics during the last deglaciation of Kveithola, W Barents Sea, as revealed by seabed geomorphology and shallow seismic stratigraphy. Boreas, 42, 84-107. Lucchi R.G., et al. 2013. Postglacial sedimentary processes on the Storfjorden and Kveithola TMFs: impact of extreme glacimarine sedimentation. Global and Planetary Change, 111, 309-326. Rebesco, M., et al. 2011. Deglaciation of the Barents Sea Ice Sheet - a swath bathymetric and subbottom seismic study from the Kveitehola Trough. Marine Geology, 279, 141-14. Rüther, D.C., Bjarnadóttir, L.R., Junttila, J., Husum, K., Rasmussen, T.L., Lucchi, R.G., Andreassen, K., 2012. Pattern and timing of the north-western Barents Sea Ice Sheet deglaciation and indications of episodic Holocene deposition. Boreas 41, 494-512.

  20. Microbial Community in the Hydrothermal System at Southern Mariana Trough

    NASA Astrophysics Data System (ADS)

    Kato, S.; Itahashi, S.; Kakegawa, T.; Utsumi, M.; Maruyama, A.; Ishibashi, J.; Marumo, K.; Urabe, T.; Yamagishi, A.

    2004-12-01

    There is unique ecosystem around deep-sea hydrothermal area. Living organisms are supported by chemical free energy provided by the hydrothermal water. The ecosystem is expected to be similar to those in early stage of life history on the earth, when photosynthetic organisms have not emerged. In this study, we have analyzed the microbial diversity in the hydrothermal area at southern Mariana trough. In the "Archaean Park Project" supported by special Coordination Fund, four holes were bored and cased by titanium pipes near hydrothermal vents in the southern Mariana trough in 2004. Hydrothermal fluids were collected from these cased holes and natural vents in this area. Microbial cells were collected by filtering the hydrothermal fluid in situ or in the mother sip. Filters were stored at -80C and used for DNA extraction. Chimneys at this area was also collected and stored at -80C. The filters and chimney samples were crushed and DNA was extracted. DNA samples were used for amplification of 16S rDNA fragments by PCR using archaea specific primers and universal primers. The PCR fragments were cloned and sequenced. These PCR clones of different samples will be compared. We will extend our knowledge about microbiological diversity at Southern Mariana trough to compare the results obtained at other area.

  1. Low cost vee-trough evacuated tube collector module

    NASA Technical Reports Server (NTRS)

    Selcuk, M. K.

    1979-01-01

    A low cost solar collector capable of operating at 150-200 C is described. An evacuated tube receiver is combined with asymmetric vee-trough concentrators. Peak efficiencies of about 40% at 120 C and 30% at 180 C are expected. Predicted future collector cost is $70/sq m which yields an energy cost of $4.20/GJ at 120 C. During the development of the vee trough/evacuated tube collector both mathematical models to predict thermal and optical performance were developed and tests run to verify theory. The asymmetric vee trough concentrator increases the solar flux intensity for an average value of 2 for year-round performance. Optimized collector module has reflector angles of 55 deg/85 deg. The aperture plane is tilted to the latitude. The reflector is made of electropolished aluminum. The supporting frame is formed by bending sheet metal. Evacuated tube receivers are Pyrex, 15 cm diam and 2.4 m long. The module has 12 tubes on right and left sides altogether. Attainable operation at temperatures on the order of 150-200 C are suitable for absorption refrigeration and power generation via Rankine engines.

  2. Pregnancy After Kidney Transplantation: Outcomes, Tacrolimus Doses, and Trough Levels.

    PubMed

    Aktürk, S; Çelebi, Z K; Erdoğmuş, Ş; Kanmaz, A G; Yüce, T; Şengül, Ş; Keven, K

    2015-06-01

    Although pregnancy after kidney transplantation has been considered as high risk for maternal and fetal complications, it can be successful in properly selected patients. It is well known that pregnancy can induce changes in the plasma concentrations of some drugs; however, there has been very limited information about tacrolimus pharmacokinetics during pregnancy. In this study, we evaluated the tacrolimus doses, blood levels, and the outcomes of pregnancies in kidney allograft recipients. From 2004 to 2014, we found 16 pregnancies in 12 kidney allograft recipients at our center. We reviewed the files and data reports including fetal outcomes, graft function, complications, tacrolimus trough levels, and doses. We analyzed the tacrolimus trough levels and doses before pregnancy, during pregnancy (monthly), and in the postpartum period. Throughout the pregnancy, we aimed to achieve tacrolimus trough levels between 4 and 7 ng/mL. All patients were on triple immunosuppression, including tacrolimus, azathioprine, and prednisolone. In total, 11 of 16 (68.7%) pregnancies were successful, with a mean weight gain of 12.5 ± 1.66 kg. One patient developed gestational diabetes mellitus and 2 had preeclampsia. Although 5 of 11 babies were found to have low birth weight, 4 of these were premature. Two patients lost their grafts, 1 due to acute rejection and the second due to progression of chronic allograft dysfunction. We have shown that tacrolimus doses need to be significantly increased to keep appropriate trough levels during pregnancy (the doses: before, 3.20 ± 0.9 mg/day; first trimester, 5.03 ± 1.5; second trimester, 6.50 ± 1.8; third trimester, 7.30 ± 2.3; post-partum, 3.5 ± 0.9). In conclusion, the dose of tacrolimus needs to be increased to provide safe and stable tacrolimus trough levels during pregnancy. Although pregnancy can be successful in most cases, it should be kept in mind that there is an increased risk of maternal and fetal complications, including

  3. Deep drivers of mesoscale circulation in the central Rockall Trough

    NASA Astrophysics Data System (ADS)

    Sherwin, T. J.; Alyenik, D.; Dumont, E.; Inall, M.

    2014-11-01

    Mesoscale variability in the central Rockall Trough between about 56 and 58° N has been investigated using a combination of ship-borne, underwater glider and gridded satellite altimeter measurements. Altimeter observations show that mesoscale features such as eddies and large scale circulation cells are ubiquitous phenomena. They have horizontal length scales of order 100 km with vertical scales of over 1000 m and are associated with mean current speeds (over the upper 1000 m) of 15 ± 7 cm s-1. Monthly area averaged surface Eddy Kinetic Energy (EKE) has substantial inter-annual variability, which at times can dominate a mean seasonal signal that varies from a maximum in May (74 cm2 s-2) to a minimum in October (52 cm2 s-2) and has increased gradually since 1992 at about 1.1 cm2 s-2 per year. A five month glider mission in the Trough showed that much of this energy comes from features that are located over 1000 m below the surface in the deep cold waters of the Trough (possibly from eddies associated the North Atlantic Current). The surface currents from altimeters had similar magnitude to the drift currents averaged over 1000 m from the glider in the stratified autumn, but were half the deep water speed during late winter. Although the mesoscale features move in an apparent random manner they may also be quasi-trapped by submarine topography such as seamounts. Occasionally anti-cyclonic and cyclonic cells combine to cause a coherent westward deflection of the European slope current that warms the Rockall side of the Trough. Such deflections contribute to the inter-annual variability in the observed temperature and salinity that are monitored in the upper 800 m of the Trough. By combining glider and altimeter measurements it is shown that altimeter measurements fail to observe a 15 cm s-1 northward flowing slope current on the eastern side and a small persistent southward current on the western side. There is much to be gained from the synergy between satellite

  4. Parabolic Flight Evaluation of Bacterial Adhesion on Multiple Antimicrobial Surface Treatments

    NASA Technical Reports Server (NTRS)

    Birmele, Michele

    2011-01-01

    This report describes the development of a test method and the evaluation of the effectiveness of antimicrobial technologies in reduced gravity based on parabolic flight experiments. Microbial growth is a common occurrence on fully immersed wetted surfaces in spacecraft environmental control and life support systems despite the use of chemical and/or physical \\disinfection. Many materials and surface treatments with antimicrobial properties are commercially available but none have been vetted for spaceflight applications. Herein a test method is explained that included ground and reduced gravity parabolic flight experiments with a standard microorganism recovered from spacecraft, Pseudomonas aeruginosa, added at a concentration of 1 x 10(exp 5) cells per milliliter (mL) onto challenge material coupon surfaces. Several experimental materials were observed to slightly reduce microbial attachment in reduced gravity flight experiments, but none were capable of eliminating all challenge bacteria. Lunar gravity had an increased antimicrobial effect in 28 out of 36 test coupons compared to microgravity when provided otherwise identical conditions for growth, suggesting trace .amounts of gravity may be required for maximum antimicrobial performance. Bacterial cells exposed to variable gravity had more than twice as ,much intracellular adenosine triphosphate (ATP) when compared to control cells exposed only to Earth gravity due to a short duration response to environmental stress. An ATP luminescence assay was the method most amenable to development of an in-flight microbial monitoring assay

  5. Electromagnetic Casimir forces of parabolic cylinder and knife-edge geometries

    SciTech Connect

    Graham, Noah; Shpunt, Alexander; Kardar, Mehran; Emig, Thorsten; Rahi, Sahand Jamal; Jaffe, Robert L.

    2011-06-15

    An exact calculation of electromagnetic scattering from a perfectly conducting parabolic cylinder is employed to compute Casimir forces in several configurations. These include interactions between a parabolic cylinder and a plane, two parabolic cylinders, and a parabolic cylinder and an ordinary cylinder. To elucidate the effect of boundaries, special attention is focused on the 'knife-edge' limit in which the parabolic cylinder becomes a half-plane. Geometrical effects are illustrated by considering arbitrary rotations of a parabolic cylinder around its focal axis, and arbitrary translations perpendicular to this axis. A quite different geometrical arrangement is explored for the case of an ordinary cylinder placed in the interior of a parabolic cylinder. All of these results extend simply to nonzero temperatures.

  6. A Review of Psycho-Physiological Responses to Parabolic Flight

    NASA Astrophysics Data System (ADS)

    Brummer, Vera; Schneider, Stefan; Guardiera, Simon; Struder, Heiko K.

    2008-06-01

    This review combines and correlates data of several studies conducted in the recent years where we were able to show an increase in stress hormone concentrations, EEG activity and a decrease in mood during parabolic flights. The aim of these studies was to consider whether previous results showing a decrease in mental and perceptual motor performance during weightlessness were solely due to the changes in gravity itself or were also, at least partly, explainable by an increase of stress and/or arousal during parabolic flights. A correlation between stress hormones and mood but not between EEG activity and mood nor between stress hormones and EEG activity could be found. We propose two different stressors: First an activation of the adrenomedullary system, secondly a general increase of cortical arousal. Whereas the first one is perceived by subjects, this is not the case for the second one.

  7. Shock wave convergence in water with parabolic wall boundaries

    SciTech Connect

    Yanuka, D.; Shafer, D.; Krasik, Ya.

    2015-04-28

    The convergence of shock waves in water, where the cross section of the boundaries between which the shock wave propagates is either straight or parabolic, was studied. The shock wave was generated by underwater electrical explosions of planar Cu wire arrays using a high-current generator with a peak output current of ∼45 kA and rise time of ∼80 ns. The boundaries of the walls between which the shock wave propagates were symmetric along the z axis, which is defined by the direction of the exploding wires. It was shown that with walls having a parabolic cross section, the shock waves converge faster and the pressure in the vicinity of the line of convergence, calculated by two-dimensional hydrodynamic simulations coupled with the equations of state of water and copper, is also larger.

  8. Accuracy-based time step criteria for solving parabolic equations

    SciTech Connect

    Mohtar, R.; Segerlind, L.

    1995-12-31

    Parabolic equations govern many transient engineering problems. Space integration using finite element or finite difference methods changes the parabolic partial differential equation into an ordinary differential equation. Time integration schemes are needed to solve the later equation. In order to accurately perform the later integration a proper time step must be provided. Time step estimates based on a stability criteria have been prescribed in the literature. The following paper presents time step estimates that satisfy stability as well as accuracy criteria. These estimates were correlated to the Froude and Courant Numbers. The later criteria were found to be overly conservative for some integration schemes. Suggestions as to which time integration scheme is the best to use are also presented.

  9. Irrigation market for solar thermal parabolic dish systems

    NASA Technical Reports Server (NTRS)

    Habib-Agahi, H.; Jones, S. C.

    1981-01-01

    The potential size of the onfarm-pumped irrigation market for solar thermal parabolic dish systems in seven high-insolation states is estimated. The study is restricted to the displacement of three specific fuels: gasoline, diesel and natural gas. The model was developed to estimate the optimal number of parabolic dish modules per farm based on the minimum cost mix of conventional and solar thermal energy required to meet irrigation needs. The study concludes that the potential market size for onfarm-pumped irrigation applications ranges from 101,000 modules when a 14 percent real discount rate is assumed to 220,000 modules when the real discount rate drops to 8 percent. Arizona, Kansas, Nebraska, New Mexico and Texas account for 98 percent of the total demand for this application, with the natural gas replacement market accounting for the largest segment (71 percent) of the total market.

  10. Water Cooled TJ Dense Array Modules for Parabolic Dishes

    NASA Astrophysics Data System (ADS)

    Löckenhoff, Rüdiger; Kubera, Tim; Rasch, Klaus Dieter

    2010-10-01

    AZUR SPACE Solar Power GmbH has developed a novel type of dense array module for use in parabolic dishes. Such dishes never produce a perfectly homogeneous, rectangular light spot but an inhomogeneous light distribution. A regular module would use this light distribution very inefficiently. Therefore AZUR SPACE developed a dense array module concept which can be adapted to inhomogeneous light spots. It is populated with state of the art triple junction solar cells. The modules are designed for light intensities in the range of 50-100 W/cm2 and are actively water cooled. Prototypes are installed in 11 m2 parabolic dishes produced by Zenith Solar. A peak output of 2.3 kW electrical and 5.5 kW thermal power could be demonstrated. The thermal power may be used for solar heating, solar cooling or warm water.

  11. Development and testing of Parabolic Dish Concentrator No. 1

    NASA Technical Reports Server (NTRS)

    Dennison, E. W.; Thostesen, T. O.

    1984-01-01

    Parabolic Dish Concentrator No. 1 (PDC-1) is a 12-m-diameter prototype concentrator with low life-cycle costs for use with thermal-to-electric energy conversion devices. The concentrator assembly features panels made of a resin transfer molded balsa core/fiberglass sandwich with plastic reflective film as the reflective surface and a ribbed framework to hold the panels in place. The concentrator assembly tracks in azimuth and elevation on a base frame riding on a circular track. It is shown that the panels do not exhibit the proper parabolic contour. However, thermal gradients were discovered in the panels with daily temperature changes. The PDC-1 has sufficient optical quality to operate satisfactorily in a dish-electric system. The PDC-1 development provides the impetus for creating innovative optical testing methods and valuable information for use in designing and fabricating concentrators of future dish-electric systems.

  12. Parabolic discounting of monetary rewards by physical effort.

    PubMed

    Hartmann, Matthias N; Hager, Oliver M; Tobler, Philippe N; Kaiser, Stefan

    2013-11-01

    When humans and other animals make decisions in their natural environments prospective rewards have to be weighed against costs. It is well established that increasing costs lead to devaluation or discounting of reward. While our knowledge about discount functions for time and probability costs is quite advanced, little is known about how physical effort discounts reward. In the present study we compared three different models in a binary choice task in which human participants had to squeeze a handgrip to earn monetary rewards: a linear, a hyperbolic, and a parabolic model. On the group as well as the individual level, the concave parabolic model explained most variance of the choice data, thus contrasting with the typical hyperbolic discounting of reward value by delay. Research on effort discounting is not only important to basic science but also holds the potential to quantify aberrant motivational states in neuropsychiatric disorders. PMID:24140077

  13. Electron trapping and acceleration across a parabolic plasma density profile.

    PubMed

    Kim, J U; Hafz, N; Suk, H

    2004-02-01

    It is known that as a laser wakefield passes through a downward density transition in a plasma some portion of the background electrons are trapped in the laser wakefield and the trapped electrons are accelerated to relativistic high energies over a very short distance. In this study, by using a two-dimensional (2D) particle-in-cell (PIC) simulation, we suggest an experimental scheme that can manipulate electron trapping and acceleration across a parabolic plasma density channel, which is easier to produce and more feasible to apply to the laser wakefield acceleration experiments. In this study, 2D PIC simulation results for the physical characteristics of the electron bunches that are emitted from the parabolic density plasma channel are reported in great detail. PMID:14995568

  14. Configuration selection study for isolated loads using parabolic dish modules

    NASA Technical Reports Server (NTRS)

    Revere, W.; Bowyer, J.; Fujita, T.; Awaya, H.

    1981-01-01

    A configuration tradeoff study has been conducted to determine optimum solar thermal parabolic dish power systems for isolated load applications. The specific application of an essentially constant power demand as required for MX missile shelters is treated. Supplying a continuous level of power with high reliability is shown to require a power system comprising modular parabolic dish power units where the heat engines of the modular power units can be driven by fossil fuels as well as solar-derived heat. Since constraints on reliability result in the provision of a power generating capability that exceeds the constant demand level, efficient utilization of the power system requires battery storage. Tradeoffs regarding the optimum size of storage are investigated as a function of the number of power modules and the cost of the fossil fuel which is used to meet the demand when insolation is unavailable and storage is depleted.

  15. Configuration selection study for isolated loads using parabolic dish modules

    NASA Technical Reports Server (NTRS)

    Revere, W.; Bowyer, J.; Fujita, T.; Awaya, H.

    1982-01-01

    A configuration tradeoff study was conducted to determine optimum solar thermal parabolic dish power systems for isolated load applications. The specific application of an essentially constant power demand as required for MX missile shelters is treated. Supplying a continuous level of power with high reliability is shown to require a power system comprising modular parabolic dish power units where the heat engines of the modular power units can be driven by fossil fuels as well as solar-derived heat. Since constraints on reliability result in the provision of a power generating capability that exceeds the constant demand level, efficient utilization of the power system requires battery storage. Tradeoffs regarding the optimum size of storage are investigated as a function of the number of power modules and the cost of the fossil fuel.

  16. Treatment of motion sickness in parabolic flight with buccal scopolamine

    NASA Technical Reports Server (NTRS)

    Norfleet, William T.; Degioanni, Joseph J.; Reschke, Millard F.; Bungo, Michael W.; Kutyna, Frank A.; Homick, Jerry L.; Calkins, D. S.

    1992-01-01

    Treatment of acute motion sickness induced by parabolic flight with a preparation of scopolamine placed in the buccal pouch was investigated. Twenty-one subjects flew aboard a KC-135 aircraft operated by NASA which performed parabolic maneuvers resulting in periods of 0-g, 1-g, and 1.8-g. Each subject flew once with a tablet containing scopolamine and once with a placebo in a random order, crossover design. Signs and symptoms of motion sickness were systematically recorded during each parabola by an investigator who was blind to the content of the tablet. Compared with flights using placebo, flights with buccal scopolamine resulted in significantly lower scores for nausea (31-35 percent reduction) and vomiting (50 percent reduction in number of parabolas with vomiting). Side effects of the drug during flight were negligible. It is concluded that buccal scopolamine is more effective than a placebo in treating ongoing motion sickness.

  17. Magnetosphere-Ionosphere Coupling Processes in the Ionospheric Trough Region During Substorms

    NASA Astrophysics Data System (ADS)

    Zou, S.; Moldwin, M.; Nicolls, M. J.; Ridley, A. J.; Coster, A. J.; Yizengaw, E.; Lyons, L. R.; Donovan, E.

    2013-12-01

    The ionospheric troughs are regions of remarkable electron density depression at the subauroral and auroral latitudes, and are categorized into the mid-latitude trough or high-latitude trough, depending on their relative location to the auroral oval. Substorms are one fundamental element of geomagnetic activity, during which structured field-aligned currents (FACs) and convection flows develop in the subauroral and auroral ionosphere. The auroral/trough region is expected to experience severe electron density variations during substorms. Accurate specification of the trough dynamics during substorms and understanding its relationship with the structured FACs and convection flows are of important practical purpose, including providing observational foundations for assessing the attendant impact on navigation and communication. In addition, troughs are important since they map to magnetospheric boundaries allowing the remote sensing of magnetosphere-ionosphere coupling processes. In this talk, we discuss the dynamics of the mid-latitude and high-latitude troughs during substorms based on multi-instrument observations. Using GPS total electron content (TEC) data, we characterize the location and width of the mid-latitude trough through the substorm lifecycle and compare them with existing trough empirical models. Using a combination of incoherent scattering radar (ISR), GPS TEC, auroral imager and a data assimilative model, we investigate the relationship between the high-latitude trough and FACs as well as convection flows. The high-latitude trough is found to be collocated with a counter-clockwise convection flow vortex east of the Harang reversal region, and downward FACs as part of the substorm current system are suggested to be responsible for the high-latitude trough formation. In addition, complex ionospheric electron temperature within the high-latitude trough is found, i.e., increase in the E region while decrease in the F region. We discuss possible

  18. Synergies between optical and physical variables in intercepting parabolic targets

    PubMed Central

    Gómez, José; López-Moliner, Joan

    2013-01-01

    Interception requires precise estimation of time-to-contact (TTC) information. A long-standing view posits that all relevant information for extracting TTC is available in the angular variables, which result from the projection of distal objects onto the retina. The different timing models rooted in this tradition have consequently relied on combining visual angle and its rate of expansion in different ways with tau being the most well-known solution for TTC. The generalization of these models to timing parabolic trajectories is not straightforward. For example, these different combinations rely on isotropic expansion and usually assume first-order information only, neglecting acceleration. As a consequence no optical formulations have been put forward so far to specify TTC of parabolic targets with enough accuracy. It is only recently that context-dependent physical variables have been shown to play an important role in TTC estimation. Known physical size and gravity can adequately explain observed data of linear and free-falling trajectories, respectively. Yet, a full timing model for specifying parabolic TTC has remained elusive. We here derive two formulations that specify TTC for parabolic ball trajectories. The first specification extends previous models in which known size is combined with thresholding visual angle or its rate of expansion to the case of fly balls. To efficiently use this model, observers need to recover the 3D radial velocity component of the trajectory which conveys the isotropic expansion. The second one uses knowledge of size and gravity combined with ball visual angle and elevation angle. Taking into account the noise due to sensory measurements, we simulate the expected performance of these models in terms of accuracy and precision. While the model that combines expansion information and size knowledge is more efficient during the late trajectory, the second one is shown to be efficient along all the flight. PMID:23720614

  19. Sea urchin fertilization during a KC-135 parabolic flight.

    PubMed

    Schatten, H; Zoran, S; Levine, H G; Anderson, K; Chakrabarti, A

    1999-07-01

    For long-term exposure to space it is crucial to understand the underlying mechanisms for altered physiological functions. We have chosen the sea urchin system to study the effects of microgravity on various cellular processes visible during fertilization and subsequent development. We report here on experiments performed on NASA's KC-135 during parabolic flight trajectories to validate procedures to be implemented as part of the first Aquatic Research Facility Space Shuttle experiment on STS-77. PMID:11543042

  20. Criteria for evaluation of reflective surface for parabolic dish concentrators

    NASA Technical Reports Server (NTRS)

    Bouquet, F.

    1980-01-01

    Commercial, second surface glass mirror are emphasized, but aluminum and metallized polymeric films are also included. Criteria for sealing solar mirrors in order to prevent environmental degradation and criteria for bonding sagged or bent mirrors to substrate materials are described. An overview of the technical areas involved in evaluating small mirror samples, sections, and entire large gores is presented. A basis for mirror criteria was established that eventually may become part of inspection and evaluation techniques for three dimensional parabolic reflective surfaces.

  1. Singular parabolic equations of second order on manifolds with singularities

    NASA Astrophysics Data System (ADS)

    Shao, Yuanzhen

    2016-01-01

    The main aim of this article is to establish an Lp-theory for elliptic operators on manifolds with singularities. The particular class of differential operators discussed herein may exhibit degenerate or singular behavior near the singular ends of the manifolds. Such a theory is of importance for the study of elliptic and parabolic equations on non-compact, or even incomplete manifolds, with or without boundary.

  2. Radiative Heat Transfer During Atmosphere Entry at Parabolic Velocity

    NASA Technical Reports Server (NTRS)

    Yoshikawa, Kenneth K.; Wick, Bradford H.

    1961-01-01

    Stagnation point radiative heating rates for manned vehicles entering the earth's atmosphere at parabolic velocity are presented and compared with corresponding laminar convective heating rates. The calculations were made for both nonlifting and lifting entry trajectories for vehicles of varying nose radius, weight-to-area ratio, and drag. It is concluded from the results presented that radiative heating will be important for the entry conditions considered.

  3. Discontinuous Galerkin Finite Element Method for Parabolic Problems

    NASA Technical Reports Server (NTRS)

    Kaneko, Hideaki; Bey, Kim S.; Hou, Gene J. W.

    2004-01-01

    In this paper, we develop a time and its corresponding spatial discretization scheme, based upon the assumption of a certain weak singularity of parallel ut(t) parallel Lz(omega) = parallel ut parallel2, for the discontinuous Galerkin finite element method for one-dimensional parabolic problems. Optimal convergence rates in both time and spatial variables are obtained. A discussion of automatic time-step control method is also included.

  4. Optimal feedback control infinite dimensional parabolic evolution systems: Approximation techniques

    NASA Technical Reports Server (NTRS)

    Banks, H. T.; Wang, C.

    1989-01-01

    A general approximation framework is discussed for computation of optimal feedback controls in linear quadratic regular problems for nonautonomous parabolic distributed parameter systems. This is done in the context of a theoretical framework using general evolution systems in infinite dimensional Hilbert spaces. Conditions are discussed for preservation under approximation of stabilizability and detectability hypotheses on the infinite dimensional system. The special case of periodic systems is also treated.

  5. Galerkin/Runge-Kutta discretizations for semilinear parabolic equations

    NASA Technical Reports Server (NTRS)

    Keeling, Stephen L.

    1987-01-01

    A new class of fully discrete Galerkin/Runge-Kutta methods is constructed and analyzed for semilinear parabolic initial boundary value problems. Unlike any classical counterpart, this class offers arbitrarily high, optimal order convergence. In support of this claim, error estimates are proved, and computational results are presented. Furthermore, it is noted that special Runge-Kutta methods allow computations to be performed in parallel so that the final execution time can be reduced to that of a low order method.

  6. Asymptotic behaviour of solutions of semilinear parabolic equations

    SciTech Connect

    Egorov, Yu V; Kondratiev, V A

    2008-04-30

    The asymptotic behaviour of solutions of a second-order semilinear parabolic equation is analyzed in a cylindrical domain that is bounded in the space variables. The dominant term of the asymptotic expansion of the solution as t{yields}+{infinity} is found. It is shown that the solution of this problem is asymptotically equivalent to the solution of a certain non-linear ordinary differential equation. Bibliography: 8 titles.

  7. Performance of a blood chemistry analyzer during parabolic flight

    NASA Technical Reports Server (NTRS)

    Spooner, Brian S.; Claassen, Dale E.; Guikema, James A.

    1990-01-01

    The performance of the Vision System Blood Analyzer during parabolic flight on a KC-135 aircraft (NASA 930) has been tested. This fully automated instrument performed flawlessly in these trials, demonstrating its potential for efficient, reliable use in a microgravity environment. In addition to instrument capability, it is demonstrated that investigators could readily fill specially modified test packs with fluid during zero gravity, and that filled test packs could be easily loaded into VISION during an episode of microgravity.

  8. A stability analysis for a semilinear parabolic partial differential equation

    NASA Technical Reports Server (NTRS)

    Chafee, N.

    1973-01-01

    The parabolic partial differential equation considered is u sub t = u sub xx + f(u), where minus infinity x plus infinity and o t plus infinity. Under suitable hypotheses pertaining to f, a class of initial data is exhibited: phi(x), minus infinity x plus infinity, for which the corresponding solutions u(x,t) appraoch zero as t approaches the limit of plus infinity. This convergence is uniform with respect to x on any compact subinterval of the real axis.

  9. Real-time optical laboratory solution of parabolic differential equations

    NASA Technical Reports Server (NTRS)

    Casasent, David; Jackson, James

    1988-01-01

    An optical laboratory matrix-vector processor is used to solve parabolic differential equations (the transient diffusion equation with two space variables and time) by an explicit algorithm. This includes optical matrix-vector nonbase-2 encoded laboratory data, the combination of nonbase-2 and frequency-multiplexed data on such processors, a high-accuracy optical laboratory solution of a partial differential equation, new data partitioning techniques, and a discussion of a multiprocessor optical matrix-vector architecture.

  10. Local density of states in parabolic quantum corrals

    NASA Astrophysics Data System (ADS)

    Trallero-Giner, C.; Ulloa, S. E.; López-Richard, V.

    2004-03-01

    Atomic manipulation and scanning tunnel microscope experiments on metal surfaces have shown that electronic states in a “quantum corral” can be locally monitored and used to analyze the nonlocal effects of perturbations. We study new corral geometries defined by families of confocal parabolas. General solutions of the Schrödinger equation for the interior problem with Dirichlet (hard wall) boundary conditions are found exactly in terms of zeroes of hypergeometric functions. We show that the Hilbert space of solutions is separated in subspaces with odd and even symmetry. We perform numerical evaluation of the zeroes and study the effects of the parabolic curvatures on the eigenvalues and eigenfunctions of the parabolic quantum corral. The evolution of the local density of states with energy as a function of parabolic corral geometry is also analyzed. We find that under suitable conditions, the distribution of state antinodes can be described as directed intensity beams, which could be used as “quantum beacons” in future generations of “quantum mirage” experiments or optical and acoustic analogs of quantum corrals for the state node distribution.

  11. Circulatory filling pressures during transient microgravity induced by parabolic flight

    NASA Technical Reports Server (NTRS)

    Latham, Ricky D.; Fanton, John W.; White, C. D.; Vernalis, Mariana N.; Crisman, R. P.; Koenig, S. C.

    1993-01-01

    Theoretical concepts hold that blood in the gravity dependent portion of the body would relocate to more cephalad compartments under microgravity. The result is an increase in blood volume in the thoraic and cardiac chambers. However, experimental data has been somewhat contradictory and nonconclusive. Early studies of peripheral venous pressure and estimates of central venous pressure (CVP) from these data did not show an increase in CVP under microgravity. However, CVP recorded in human volunteers during a parabolic flight revealed an increase in CVP during the microgravity state. On the STS 40 shuttle mission, a payload specialist wore a fluid line that recorded CVP during the first few hours of orbital insertion. These data revealed decreased CVP. When this CVP catheter was tested during parabolic flight in four subjects, two had increased CVP recordings and two had decreased CVP measurements. In 1991, our laboratory performed parabolic flight studies in several chronic-instrumented baboons. It was again noted that centrally recorded right atrial pressure varied with exposure to microgravity, some animals having an increase, and others a decrease.

  12. Application of parabolic reflector on Raman analysis of gas samples

    NASA Astrophysics Data System (ADS)

    Yu, Anlan; Zuo, Duluo; Gao, Jun; Li, Bin; Wang, Xingbing

    2016-05-01

    Studies on the application of a parabolic reflector in spontaneous Raman scattering for low background Raman analysis of gas samples are reported. As an effective signal enhancing sample cell, photonic bandgap fiber (HC-PBF) or metallined capillary normally result in a strong continuous background in spectra caused by the strong Raman/fluorescence signal from the silica wall and the polymer protective film. In order to obtain enhanced signal with low background, a specially designed sample cell with double-pass and large collecting solid angle constructed by a parabolic reflector and a planar reflector was applied, of which the optical surfaces had been processed by diamond turning and coated by silver film and protective film of high-purity alumina. The influences of optical structure, polarization characteristic, collecting solid-angle and collecting efficiency of the sample cell on light propagation and signal enhancement were studied. A Raman spectrum of ambient air with signal to background ratio of 94 was acquired with an exposure time of 1 sec by an imaging spectrograph. Besides, the 3σ limits of detection (LOD) of 7 ppm for H2, 8 ppm for CO2 and 12 ppm for CO were also obtained. The sample cell mainly based on parabolic reflector will be helpful for compact and high-sensitive Raman system.

  13. Convergence of shock waves between conical and parabolic boundaries

    NASA Astrophysics Data System (ADS)

    Yanuka, D.; Zinowits, H. E.; Antonov, O.; Efimov, S.; Virozub, A.; Krasik, Ya. E.

    2016-07-01

    Convergence of shock waves, generated by underwater electrical explosions of cylindrical wire arrays, between either parabolic or conical bounding walls is investigated. A high-current pulse with a peak of ˜550 kA and rise time of ˜300 ns was applied for the wire array explosion. Strong self-emission from an optical fiber placed at the origin of the implosion was used for estimating the time of flight of the shock wave. 2D hydrodynamic simulations coupled with the equations of state of water and copper showed that the pressure obtained in the vicinity of the implosion is ˜7 times higher in the case of parabolic walls. However, comparison with a spherical wire array explosion showed that the pressure in the implosion vicinity in that case is higher than the pressure in the current experiment with parabolic bounding walls because of strong shock wave reflections from the walls. It is shown that this drawback of the bounding walls can be significantly minimized by optimization of the wire array geometry.

  14. H-measures and variants applied to parabolic equations

    NASA Astrophysics Data System (ADS)

    Antonic, Nenad; Lazar, Martin

    2008-07-01

    Since their introduction H-measures have been mostly used in problems related to propagation effects for hyperbolic equations and systems. In this study we give an attempt to apply the H-measure theory to other types of equations. Through a number of examples we present how do the differences between parabolic and hyperbolic equations reflect in the properties of H-measures corresponding to the solutions. Secondly, we apply the H-measures to the Schrödinger equation, where we succeed in proving a propagation property. However, our conclusion is that a variant of H-measures should be sought which would be better suited to parabolic problems. We propose such a variant, show some fundamental properties and illustrate its applicability by some examples. In particular, we show that the variant provides new information in a number of situations where the original H-measures did not. Finally, we describe how the new variant can be used in small amplitude homogenisation of parabolic equations.

  15. Three-dimensional distribution of random velocity inhomogeneities at the Nankai trough seismogenic zone

    NASA Astrophysics Data System (ADS)

    Takahashi, T.; Obana, K.; Yamamoto, Y.; Nakanishi, A.; Kaiho, Y.; Kodaira, S.; Kaneda, Y.

    2012-12-01

    The Nankai trough in southwestern Japan is a convergent margin where the Philippine sea plate is subducted beneath the Eurasian plate. There are major faults segments of huge earthquakes that are called Tokai, Tonankai and Nankai earthquakes. According to the earthquake occurrence history over the past hundreds years, we must expect various rupture patters such as simultaneous or nearly continuous ruptures of plural fault segments. Japan Agency for Marine-Earth Science and Technology (JAMSTEC) conducted seismic surveys at Nankai trough in order to clarify mutual relations between seismic structures and fault segments, as a part of "Research concerning Interaction Between the Tokai, Tonankai and Nankai Earthquakes" funded by Ministry of Education, Culture, Sports, Science and Technology, Japan. This study evaluated the spatial distribution of random velocity inhomogeneities from Hyuga-nada to Kii-channel by using velocity seismograms of small and moderate sized earthquakes. Random velocity inhomogeneities are estimated by the peak delay time analysis of S-wave envelopes (e.g., Takahashi et al. 2009). Peak delay time is defined as the time lag from the S-wave onset to its maximal amplitude arrival. This quantity mainly reflects the accumulated multiple forward scattering effect due to random inhomogeneities, and is quite insensitive to the inelastic attenuation. Peak delay times are measured from the rms envelopes of horizontal components at 4-8Hz, 8-16Hz and 16-32Hz. This study used the velocity seismograms that are recorded by 495 ocean bottom seismographs and 378 onshore seismic stations. Onshore stations are composed of the F-net and Hi-net stations that are maintained by National Research Institute for Earth Science and Disaster Prevention (NIED) of Japan. It is assumed that the random inhomogeneities are represented by the von Karman type PSDF. Preliminary result of inversion analysis shows that spectral gradient of PSDF (i.e., scale dependence of

  16. Nested parabolic reflective optics for laser plasmas

    SciTech Connect

    O`Hara, D.

    1995-12-31

    Applications for laboratory soft-x-ray/VuV sources would benefit from the ability to collect a large energy bandwidth of radiation emanating from the very small source and redirect it into a well collimated beam without losing most of the incident radiation. Such optics would be beneficial to x-ray spectroscopy, x-ray lithography, diffractometry and other applications. The author has been working to apply technology originally developed for astronomical x-ray telescopes to production of low cost replicated collimation optics for such x-ray/VuV instruments. Most of the steps in the production of these optics have previously been accomplished with the larger astronomical optics but the author wants to reduce the size of these optics by at least an order of magnitude which introduces problems. In addition, very few copies of an x-ray telescope are made while he wants to make hundreds of copies of the optics. This paper briefly discusses the design and fabrication of these small collimation optics and is a report on work in progress.

  17. Dense-array concentrator photovoltaic system using non-imaging dish concentrator and crossed compound parabolic concentrator

    NASA Astrophysics Data System (ADS)

    Chong, Kok-Keong; Yew, Tiong-Keat; Wong, Chee-Woon; Tan, Ming-Hui; Tan, Woei-Chong; Lai, An-Chow; Lim, Boon-Han; Lau, Sing-Liong; Rahman, Faidz Abdul

    2015-04-01

    Solar concentrating device plays an important role by making use of optical technology in the design, which can be either reflector or lens to deliver high flux of sunlight onto the Concentrator Photovoltaic (CPV) module receiver ranging from hundreds to thousand suns. To be more competitive compared with fossil fuel, the current CPV systems using Fresnel lens and Parabolic dish as solar concentrator that are widely deployed in United States, Australia and Europe are facing great challenge to produce uniformly focused sunlight on the solar cells as to reduce the cost of electrical power generation. The concept of non-imaging optics is not new, but it has not fully explored by the researchers over the world especially in solving the problem of high concentration solar energy, which application is only limited to be a secondary focusing device or low concentration device using Compound Parabolic Concentrator. With the current advancement in the computer processing power, we has successfully invented the non-imaging dish concentrator (NIDC) using numerical simulation method to replace the current parabolic dish as primary focusing device with high solar concentration ratio (more than 400 suns) and large collective area (from 25 to 125 m2). In this paper, we disclose our research and development on dense array CPV system based on non-imaging optics. The geometry of the NIDC is determined using a special computational method. In addition, an array of secondary concentrators, namely crossed compound parabolic concentrators, is also proposed to further focus the concentrated sunlight by the NIDC onto active area of solar cells of the concentrator photovoltaic receiver. The invention maximizes the absorption of concentrated sunlight for the electric power generation system.

  18. On uniqueness theorem on weak solutions to the parabolic-parabolic Keller-Segel system of degenerate and singular types

    NASA Astrophysics Data System (ADS)

    Miura, Masanari; Sugiyama, Yoshie

    2014-12-01

    The uniqueness of weak solutions to the parabolic-parabolic Keller-Segel systems (KS)m below with m>max⁡{1/2 >-1n,0} is proved in the class of Hölder continuous functions for any space dimension n. Since Hölder continuity is an optimal regularity for weak solutions of the porous medium equation, it seems to be reasonable to investigate its uniqueness in such a class of solutions. Our proof is based on the standard duality argument coupled with vanishing viscosity method which recovers degeneracy for m>1, and which removes singularities for 0

  19. On the complex structures of the Biswas-Milovic equation for power, parabolic and dual parabolic law nonlinearities

    NASA Astrophysics Data System (ADS)

    Manafian, Jalil

    2015-12-01

    We apply the Exp-function method (EFM) to the Biswas-Milovic equation and derive the exact solutions. This paper studies the Biswas-Milovic equation with power law, parabolic law and dual parabolic law nonlinearities by the aid of the Exp-function method. The obtained solutions not only constitute a novel analytical viewpoint in nonlinear complex phenomena, but they also form a new stand alone basis from which physical applications in this arena can be comprehended further, and, moreover, investigated. Furthermore, to concretely enrich this research production, we explain all cases, namely m=1 and m≥ 2. This method is developed for searching exact travelling-wave solutions of nonlinear partial differential equations. It is shown that this methods, with the help of symbolic computation, provides a straightforward and powerful mathematical tool for solving nonlinear partial differential equations in mathematical physics.

  20. Tufts submarine fan: turbidity-current gateway to Escanaba Trough

    USGS Publications Warehouse

    Reid, Jane A.; Normark, William R.

    2003-01-01

    Turbidity-current overflow from Cascadia Channel near its western exit from the Blanco Fracture Zone has formed the Tufts submarine fan, which extends more than 350 km south on the Pacific Plate to the Mendocino Fracture Zone. For this study, available 3.5-kHz high-resolution and airgun seismic-reflection data, long-range side-scan sonar images, and sediment core data are used to define the growth pattern of the fan. Tufts fan deposits have smoothed and filled in the linear ridge-and-valley relief over an area exceeding 23,000 km2 on the west flank of the Gorda Ridge. The southernmost part of the fan is represented by a thick (as much as 500 m) sequence of turbidite deposits ponded along more than 100 km of the northern flank of the Mendocino Fracture Zone. Growth of the Tufts fan now permits turbidity-current overflow from Cascadia Channel to reach the Escanaba Trough, a deep rift valley along the southern axis of the Gorda Ridge. Scientific drilling during both the Deep Sea Drilling Project (DSDP) and the Ocean Drilling Program (ODP) provided evidence that the 500-m-thick sediment fill of Escanaba Trough is dominantly sandy turbidites. Radiocarbon dating of the sediment at ODP Site 1037 showed that deposition of most of the upper 120 m of fill was coincident with Lake Missoula floods and that the provenance of the fill is from the eastern Columbia River drainage basin. The Lake Missoula flood discharge with its entrained sediment continued flowing downslope upon reaching the ocean as hyperpycnally generated turbidity currents. These huge turbidity currents followed the Cascadia Channel to reach the Pacific Plate, where overbank flow provided a significant volume of sediment on Tufts fan and in Escanaba Trough. Tufts fan and Tufts Abyssal Plain to the west probably received turbidite sediment from the Cascadia margin during much of the Pleistocene.

  1. Lupus-anticoagulant testing at NOAC trough levels.

    PubMed

    Ratzinger, Franz; Lang, Mona; Belik, Sabine; Jilma-Stohlawetz, Petra; Schmetterer, Klaus G; Haslacher, Helmuth; Perkmann, Thomas; Quehenberger, Peter

    2016-08-01

    Non-vitamin K antagonist oral anticoagulants (NOAC), including rivaroxaban, apixaban or dabigatran, regularly show relevant effects on coagulation tests, making the interpretation of results difficult. The aim of this study was to evaluate possible interferences of NOACs in trough level concentrations in lupus anticoagulant (LA) testing. Citrate plasma specimens of 30 healthy volunteers were spiked with rivaroxaban, apixaban or dabigatran in four plasma concentration levels at or below trough NOAC levels. The NOAC concentration was measured using dedicated surrogate concentration tests and a stepwise diagnostic procedure for LA-testing was applied using screening, mixing and confirmatory testing. Results were compared to NOAC-free specimens. Starting with a plasma concentration of 12.5 ng/ml, dabigatran-spiked specimens showed significant prolongations in the lupus anticoagulant-sensitive activated partial thromboplastin time (aPTT-LA) as well as in the Dilute Russell viper venom time (dRVVT), leading to 43.3 % false positives in confirmatory testing in the dRVVT. In contrast, rivaroxaban, beginning with 7.5 ng/ml, exclusively affected dRVVT-based tests. In confirmatory tests, 30.0 % of rivaroxaban-spiked specimens showed false positive results. Starting with 18.75 ng/ml apixaban, a significant prolongation of the dRVVT and up to 20.7 % false positives in confirmatory tests were found. In contrast to other NOACs tested, apixaban did not present with a dose-dependent increase of the dRVVT ratio. In conclusion, the rate of false positive results in LA-testing is unacceptably high at expected trough levels of NOACs. Even at plasma concentrations below the LLOQ of commercially available surrogate tests, LA testing is best avoided in patients with NOAC therapy. PMID:27075441

  2. Lateral Meniscal Allograft Transplantation: The Bone Trough Technique.

    PubMed

    Chahla, Jorge; Olivetto, Javier; Dean, Chase S; Serra Cruz, Raphael; LaPrade, Robert F

    2016-04-01

    The lateral meniscus plays a critical role in the stability and health of the knee. Treating patients who have undergone a total lateral meniscectomy or functional equivalent is challenging, especially young and active patients. Current literature regarding meniscal tears supports that repair should be the first surgical option. Moreover, it is recommended to preserve as much meniscal tissue as possible. In cases in which a total or functional meniscectomy is a pre-existing condition, a lateral meniscal allograft transplantation is a possible option. The purpose of this surgical technique description was to detail the method of lateral meniscal allograft transplantation using a bone trough. PMID:27462536

  3. Deep drivers of mesoscale circulation in the central Rockall Trough

    NASA Astrophysics Data System (ADS)

    Sherwin, T. J.; Aleynik, D.; Dumont, E.; Inall, M. E.

    2015-05-01

    Mesoscale variability in the central Rockall Trough, immediately west of the British Isles, has been investigated using a combination of ship-borne, underwater glider and gridded satellite altimeter measurements. Altimeter observations show that eddies and large-scale circulation cells are ubiquitous phenomena. They have horizontal length scales of order 100 km with vertical scales of over 1000 m and are associated with mean current speeds (over the upper 1000 m) of 15 ± 7 cm s-1. Monthly area averaged surface eddy kinetic energy (EKE) has substantial inter-annual variability, which at times can dominate a mean seasonal signal that varies from a maximum in May (74 cm2 s-2) to a minimum in October (52 cm2 s-2) and has increased gradually since 1992 at about 1.1 cm2 s-2 per year. This increase may be related to the retreat of the sub-polar gyre (SPG). A 5 month glider mission in the trough showed that the cyclonic component of EKE came from cold water features that are located over 1000 m below the surface. The surface currents from altimeters had similar magnitude to the drift currents averaged over 1000 m from the glider in the stratified autumn, but were half the deep water speed during late winter. Although the mesoscale features move in an apparent random manner, they seem to be constrained by submarine topography such as seamounts. Occasionally anti-cyclonic and cyclonic cells combine to cause a coherent westward deflection of the European slope current that warms the Rockall side of the trough. Such deflections contribute to the inter-annual variability in the observed temperature and salinity that are monitored in the upper 800 m of the trough. By combining glider and altimeter measurements it is shown that altimeter measurements fail to observe a 15 cm s-1 northward flowing slope current on the eastern side as well as a small persistent southward current on the western side. There is much to be gained from the synergy between satellite altimetry and in situ

  4. Scintillation near the F-layer trough over Northern Europe

    SciTech Connect

    Kersley, L.; Pryse, S.E.; Russell, C.D.

    1990-05-03

    Results are presented of scintillation observations made during a two and a half year period at Lerwick in the Shetland Islands using more than 19000 passes of NNSS satellites. Examples of scintillation morphology, in the region near the scintillation boundary and the F-layer trough, for both amplitude and phase are discussed using exceedence levels for the S sub 4 and sigma sub psi indices respectively. The equatorwards advancement of the scintillation boundary in response to enhanced solar activity during the increasing phase of the solar cycle is shown to be a dominant feature in the observations.

  5. Parabolic solar cooker: Cooking with heat pipe vs direct spiral copper tubes

    NASA Astrophysics Data System (ADS)

    Craig, Omotoyosi O.; Dobson, Robert T.

    2016-05-01

    Cooking with solar energy has been seen by many researchers as a solution to the challenges of poverty and hunger in the world. This is no exception in Africa, as solar coking is viewed as an avenue to eliminate the problem of food insecurity, insufficient energy supply for household and industrial cooking. There are several types of solar cookers that have been manufactured and highlighted in literature. The parabolic types of solar cookers are known to reach higher temperatures and therefore cook faster. These cookers are currently being developed for indoor cooking. This technology has however suffered low cooking efficiency and thus leads to underutilization of the high heat energy captured from the sun in the cooking. This has made parabolic solar cookers unable to compete with other conventional types of cookers. Several methods to maximize heat from the sun for indirect cooking has been developed, and the need to improve on them of utmost urgency. This paper investigates how to optimize the heat collected from the concentrating types of cookers by proposing and comparing two types of cooking sections: the spiral hot plate copper tube and the heat pipe plate. The system uses the concentrating solar parabolic dish technology to focus the sun on a conical cavity of copper tubes and the heat is stored inside an insulated tank which acts both as storage and cooking plate. The use of heat pipes to transfer heat between the oil storage and the cooking pot was compared to the use of a direct natural syphon principle which is achieved using copper tubes in spiral form like electric stove. An accurate theoretical analysis for the heat pipe cooker was achieved by solving the boiling and vaporization in the evaporator side and then balancing it with the condensation and liquid-vapour interaction in the condenser part while correct heat transfer, pressure and height balancing was calculated in the second experiment. The results show and compare the cooking time, boiling

  6. Application and Operations Concepts of Large Transmit Phased Array of Parabolic Reflectors

    NASA Technical Reports Server (NTRS)

    Amoozegar, Farid

    2006-01-01

    The primary motive for large transmit array of parabolic reflectors, also known as Uplink Array, was to explore alternate methods in order to replace the large 70m antennas of Deep Space Network (DSN) such that the core capability for emergency support to a troubled spacecraft in deep space is preserved. Given that the Uplink Array is a new technology, the focus has always been on its feasibility and phase calibration techniques, which by itself is quite a challenge. It would be interesting to examine, however, what else could be accomplished by the Uplink Array capability other than the emergency support to a troubled spacecraft in deep space. ... The objective of this paper is to discuss a few application scenarios and the corresponding operation concepts, such as lunar positioning system, high EIRP uplink and the synergies with solar radar, and high power RF beams.

  7. Double troughs in broad absorption line quasars and Ly-alpha-N V line-locking

    NASA Technical Reports Server (NTRS)

    Korista, Kirk T.; Voit, G. M.; Morris, Simon L.; Weymann, Ray J.

    1993-01-01

    It was investigated whether the double trough (DT) structure in the mean C IV BAL trough reported by Weymann et al. (1991) is real or due to statistical fluctuations of BAL troughs over random outflow velocities in a limited sample. A sample of 72 BAL QSOs with C IV BAL troughs was analyzed. It is found that only 22 percent of the sample explicitly exhibits the DT feature; when present the DTs are deep. A Monte Carlo simulation of the mean C IV BAL suggests that the DT feature is real at only the 95-98 percent level.

  8. The 1946 Nankai earthquake and segmentation of the Nankai Trough

    NASA Astrophysics Data System (ADS)

    Cummins, Phil R.; Baba, Toshitaka; Kodaira, Shuichi; Kaneda, Yoshiyuki

    2002-09-01

    We perform a simple subevent analysis of seismic P-waveforms from historical records of the 1946 Nankai earthquake. The results of this analysis establish that the earthquake rupture consisted of two main subevents, one lying within the 1-day aftershock area off the Kii Peninsula, while the other lies much farther to the west in the area of pronounced crustal deformation of western Shikoku. These conform to two segments of the Nankai Trough which have long been referred to in studies of historical earthquakes and geology of the Nankai Trough, but to our knowledge have not previously been established as having distinct megathrust rupture behavior. We show that these two subevents are bounded by pronounced features in the geometry of the subducting Philippine Sea Plate (PSP): a tear in the plate to the east beneath the Kii Peninsula, and a subducting seamount farther to the west. We speculate that these features may be associated with low-strength parts of the upper and/or lower plates that may be susceptible to permanent, anelastic deformation which prevents the accumulation of the elastic strain energy necessary to sustain seismic rupture.

  9. Geodetic investigation into the deformation of the Salton Trough

    NASA Astrophysics Data System (ADS)

    Crowell, Brendan W.; Bock, Yehuda; Sandwell, David T.; Fialko, Yuri

    2013-09-01

    Salton Trough represents a complex transition between the spreading center in Baja California and the strike-slip San Andreas fault system and is one of the most active zones of deformation and seismicity in California. We present a high-resolution interseismic velocity field for the Salton Trough derived from 74 continuous GPS sites and 109 benchmarks surveyed in three GPS campaigns during 2008-2009 and previous surveys between 2000 and 2005. We also investigate small-scale deformation by removing the regional velocity field predicted by an elastic block model for Southern California from the observed velocities. We find a total extension rate of 11 mm/yr from the Mesquite Basin to the southern edge of the San Andreas Fault, coupled with 15 mm/yr of left-lateral shear, the majority of which is concentrated in the southern Salton Sea and Obsidian Buttes and is equivalent to 17 mm/yr oriented in the direction of the San Andreas Fault. Differential shear strain is exclusively localized in the Brawley Seismic Zone, and dilatation rate indicates widespread extension throughout the zone. In addition, we infer clockwise rotation of 10°/Ma, consistent with northwestward propagation of the Brawley Seismic Zone over geologic time.

  10. Scroll wave drift along steps, troughs, and corners

    NASA Astrophysics Data System (ADS)

    Ke, Hua; Zhang, Zhihui; Steinbock, Oliver

    2015-06-01

    Three-dimensional excitable systems can create nonlinear scroll waves that rotate around one-dimensional phase singularities. Recent theoretical work predicts that these filaments drift along step-like height variations. Here, we test this prediction using experiments with thin layers of the Belousov-Zhabotinsky reaction. We observe that over short distances scroll waves are attracted towards the step and then rapidly commence a steady drift along the step line. The translating filaments always reside on the shallow side of the step near the edge. Accordingly, filaments in the deep domain initially collide with and shorten at the step wall. The drift speeds obey the predicted proportional dependence on the logarithm of the height ratio and the direction depends on the vortex chirality. We also observe drift along the perimeter of rectangular plateaus and find that the filaments perform sharp turns at the corners. In addition, we investigate rectangular troughs for which vortices of equal chirality can drift in different directions. The latter two effects are reproduced in numerical simulations with the Barkley model. The simulations show that narrow troughs instigate scroll wave encounters that induce repulsive interaction and symmetry breaking. Similar phenomena could exist in the geometrically complicated ventricles of the human heart where reentrant vortex waves cause tachycardia and fibrillation.

  11. Observations of mesoscale variability in the Rockall Trough

    NASA Astrophysics Data System (ADS)

    Ullgren, J. E.; White, M.

    2012-06-01

    The Rockall Trough west of Ireland displays a high level of mesoscale activity for an eastern ocean boundary region. Eddies off the continental slope at 50-56°N have been studied using a combination of in situ observations of current velocity and hydrography from two deep-sea moorings at the southern entrance to the Trough, and data from satellite altimetry and Argo floats. South of Rockall-Hatton Plateau, where a branch of the NAC enters the region from the west, more cyclonic eddies are found, while anticyclonic eddies dominate along the path of the Slope Current in the east. Temperature-salinity profiles from the perimeters of a cyclone and an anticyclone, respectively, show large differences on isopycnals both at the level of the subsurface salinity maximum and at intermediate depths. Anticyclonic eddies likely formed by instabilities of the Slope Current can include a parcel of salty Mediterranean Water (MW) at the intermediate level, contributing to the patchy distribution of MW in the region.

  12. Ouachita trough: Part of a Cambrian failed rift system

    NASA Astrophysics Data System (ADS)

    Lowe, Donald R.

    1985-11-01

    Pre-flysch (Cambrian-Mississippian) strata of the Ouachita Mountains of Arkansas and Oklahoma include two main sandstone lithofacies: (1) a craton-derived lithofacies made up largely of mature medium- to coarse-grained quartzose and carbonate detritus and, in some units, sediment eroded from exposed basement rocks and (2) an orogen-derived facies made up mainly of fine-grained quartzose sedimentary and metasedimentary debris and possibly, in lower units, a volcaniclastic component. Paleocurrent and distribution patterns indicate that detritus of facies I in the Benton uplift was derived from north and detritus of facies II throughout the Ouachitas was derived from south and east of the depositional basin. Overall sedimentological results suggest that the Ouachita trough was a relatively narrow, two-sided basin throughout most and probably all of its existence and never formed the southern margin of the North American craton. Regional comparisons suggest that it was one of several basins, including the Southern Oklahoma aulacogen, Reelfoot Rift, Illinois Basin, and Rome trough, that formed as a Cambrian failed rift system 150 to 250 m.y. after initial rifting along the Appalachian margin of the North American craton.

  13. Numerical simulations for parabolic pulse shaping in non-linear media

    NASA Astrophysics Data System (ADS)

    Nora, R. C.; Durfee, C. G.; Carr, L. D.

    2007-03-01

    Pulses with parabolic temporal profiles have the property that they can propagate through non-linear media in a self similar manner. Parabolic pulses have been generated experimentally in fiber amplifiers. Input pulses develop into parabolic pulses by the combined action of group velocity dispersion, non-linear refractive index, and gain. In this work, we are exploring the feasibility of generating ultrafast parabolic pulses in laser resonators. We have successfully numerically simulated the generation of parabolic pulses in fiber amplifiers using two different algorithms, the Cayley method, and fourth order Runge-Kutta, to solve the Nonlinear Schrodinger equation with gain and periodic boundary conditions. In contrast to fiber amplifiers, pulses in laser resonators must maintain a stable pulse shape on each round trip through the optical cavity. We are exploring the prediction that a time dependent saturable gain will stabilize the pulse in the oscillator and yield parabolic pulses.

  14. Periodic-parabolic eigenvalue problems with a large parameter and degeneration

    NASA Astrophysics Data System (ADS)

    Daners, Daniel; Thornett, Christopher

    2016-07-01

    We consider a periodic-parabolic eigenvalue problem with a non-negative potential λm vanishing on a non-cylindrical domain Dm satisfying conditions similar to those for the parabolic maximum principle. We show that the limit as λ → ∞ leads to a periodic-parabolic problem on Dm having a periodic-parabolic principal eigenvalue and eigenfunction which are unique in some sense. We substantially improve a result from [Du and Peng, Trans. Amer. Math. Soc. 364 (2012), p. 6039-6070]. At the same time we offer a different approach based on a periodic-parabolic initial boundary value problem. The results are motivated by an analysis of the asymptotic behaviour of positive solutions to semilinear logistic periodic-parabolic problems with temporal and spacial degeneracies.

  15. Seafloor glacial geomorphology in a cross shelf trough: insights into the deglaciation of the Melville Bay Ice Stream

    NASA Astrophysics Data System (ADS)

    Newton, Andrew; Huuse, Mads

    2016-04-01

    Compared to other glaciated margins such as offshore mid-Norway and Svalbard, the Greenland continental shelf has, until recently, been the subject of only a limited amount of academic and industry research. This has been mainly due to the difficulty and expense of obtaining data in such harsh and operationally complex settings. Climate amelioration and technological advance has, particularly in recent years, allowed both academics and industry to substantially increase data collection across the many glaciated continental shelves in the Northern Hemisphere. Baffin Bay has been one of the primary regions of interest for the hydrocarbon industry which has sought to operate in the frontier basins offshore Greenland. As a result of these industry operations, a large database of geophysical and geological data has been collected. Some of this data has been made available to glacial scientists and provides a unique opportunity to investigate the seafloor geomorphology for regions where the majority of previous work has been hypothetical rather than grounded in geological evidence. In the work presented here we present a landform record offshore NW Greenland in the Melville Bay cross-shelf trough. This is one of the largest troughs on the entire Greenland shelf and measures up to 140 km in width. Shallow-marine cores collected in the coastal part of the trough show bedrock of Miocene age and indicate that a significant cover has likely been removed from the shelf by ice streams operating through the Late Cenozoic. This material has then been deposited at the shelf edge as a trough mouth fan. Using multibeam and seismic reflection data a large number of glacial landforms are observed and mapped in the trough. These include mega-scale glacial lineations, grounding-zone wedges, iceberg scours, and iceberg grounding pits. These landforms are used to reconstruct the ice dynamics of the Melville Bugt Ice Stream at the last glacial maximum and during its deglaciation. The

  16. The ABCD matrix for parabolic reflectors and its application to astigmatism free four-mirror cavities

    NASA Astrophysics Data System (ADS)

    Dupraz, K.; Cassou, K.; Martens, A.; Zomer, F.

    2015-10-01

    The ABCD matrix for parabolic reflectors is derived for any incident angles. It is used in numerical studies of four-mirror cavities composed of two flat and two parabolic mirrors. Constraints related to laser beam injection efficiency, optical stability, cavity-mode, beam-waist size and high stacking power are satisfied. A dedicated alignment procedure leading to stigmatic cavity-modes is employed to overcome issues related to the optical alignment of parabolic reflectors.

  17. Moon and Mars gravity environment during parabolic flights: a new European approach to prepare for planetary exploration

    NASA Astrophysics Data System (ADS)

    Pletser, Vladimir; Clervoy, Jean-Fran; Gharib, Thierry; Gai, Frederic; Mora, Christophe; Rosier, Patrice

    Aircraft parabolic flights provide repetitively up to 20 seconds of reduced gravity during ballis-tic flight manoeuvres. Parabolic flights are used to conduct short microgravity investigations in Physical and Life Sciences and in Technology, to test instrumentation prior to space flights and to train astronauts before a space mission. The European Space Agency (ESA) has organized since 1984 more than fifty parabolic flight campaigns for microgravity research experiments utilizing six different airplanes. More than 600 experiments were conducted spanning several fields in Physical Sciences and Life Sciences, namely Fluid Physics, Combustion Physics, Ma-terial Sciences, fundamental Physics and Technology tests, Human Physiology, cell and animal Biology, and technical tests of Life Sciences instrumentation. Since 1997, ESA uses the Airbus A300 'Zero G', the largest airplane in the world used for this type of experimental research flight and managed by the French company Novespace, a subsidiary of the French space agency CNES. From 2010 onwards, ESA and Novespace will offer the possibility of flying Martian and Moon parabolas during which reduced gravity levels equivalent to those on the Moon and Mars will be achieved repetitively for periods of more than 20 seconds. Scientists are invited to submit experiment proposals to be conducted at these partial gravity levels. This paper presents the technical capabilities of the Airbus A300 Zero-G aircraft used by ESA to support and conduct investigations at Moon-, Mars-and micro-gravity levels to prepare research and exploration during space flights and future planetary exploration missions. Some Physiology and Technology experiments performed during past ESA campaigns at 0, 1/6 an 1/3 g are presented to show the interest of this unique research tool for microgravity and partial gravity investigations.

  18. Carbonate system at Iheya North in Okinawa Trough~IODP drilling and post drilling environment~

    NASA Astrophysics Data System (ADS)

    Noguchi, T.; Hatta, M.; Sunamura, M.; Fukuba, T.; Suzue, T.; Kimoto, H.; Okamura, K.

    2012-12-01

    The Iheya North hydrothermal field in middle Okinawa Trough is covered with thick hemipelagic and volcanic sediment. Geochemical characteristics of Okinawa Trough is to provide abundant of CO2, CH4, NH4, H2, and H2S which originated from magmatic gases, sedimentary organic matters. On this hydrothermal field, a scientific drilling by Integrated Ocean Drilling Program (IODP) Expedition 331 was conducted to investigate metabolically diverse subseafloor microbial ecosystem and their physical and chemical settings. To clarify the spatial distribution of physical condition beneath seafloor around the hydrothermal filed, we focus on the carbonate species analysis to reconstruct in-situ pH, which regulate the diversities of microbial community and mineral composition. We developed the small sample volume dissolved total inorganic carbon (DIC) analyzer and conducted the onboard analysis for the interstitial water during IODP Exp.331. Total alkalinity, boron, phosphate, and ammonium also analyzed for thermodynamic calculation. In this presentation, we represent the spatial distribution of pH beneath the Iheya North hydrothermal field. In addition, we developed a 128 bottles multiple water sampler (ANEMONE) for post drilling environmental monitoring. ANEMONE sampler was deployed on the manned submersible Shinkai 6500 with other chemical sensors (CTD, turbidity, pH, ORP, and H2S), and collected the hydrothermal plume samples every 5 minutes during YK12-05 cruise by R/V Yokosuka (Japan Agency for Marine-Earth Science and Technology, JAMSTEC). DIC concentration of plume samples collected by ANEMONE sampler were analyzed just after submersible retrieve, and nutrients, manganese, density, and total cell counts determination were conducted onshore analysis. Based on these results, we describe the spatial distribution of DIC and carbonate system on Iheya North hydrothermal field (interstitial water, hydrothermal fluid, and hydrothermal plume).

  19. Dexterous Manipulation in Microgravity in Parabolic Flights and on ISS

    NASA Astrophysics Data System (ADS)

    Pletser, V.; Sundblad, P.; Thonnard, J.-L.; Lefevre, P.; McIntyre, J.; Kassel, R.; Derkinderen, W.; Penta, M.; Andre, T.

    It has been shown that during exposure to microgravity in parabolic flights the control of interaction forces when manipulating an object adapts partially to the lack of gravity, yet evidence indicates that anticipation of gravity's effects persists in the short term. The motivation for these experiments to be performed in long-duration space flight is to understand how the central nervous system adapts to an environment without gravity and what will be the consequences of long-term adaptation when an individual returns to a normal (Earth) or partial (Moon or Mars) gravitational field. The experiment “Dexterous Manipulation in Microgravity” (DEX) will target specific questions about the effects of gravity on dexterous manipulation, questions that cannot be addressed in the normal terrestrial environment. Some of the scientific questions have already been studied since nearly ten years and will continue to be addressed in experiments conducted in parabolic flights, during which it will be examined how the nervous system copes with repeated transitions between different gravitational environments. Results from these experiments provide initial data about short-term adaptation to 0g. The experiments proposed for ISS draw from these short-term precursor experiments, but will emphasize long-term adaptation of sensorimotor processes to 0g and re-adaptation to 1g. A first conceptual definition phase of a DEX instrument has been completed under an ESA contract and is now ready to enter into the design and development phase in view of a launch on ISS in the 2013-2014 timeframe. In this paper, the science background will be recalled and several experiments performed during parabolic flights will be presented, showing how these early breadboards testing in microgravity have helped to refine the DEX conceptual design and how it could be used on ISS.

  20. Processing of data from innovative parabolic strip telescope.

    NASA Astrophysics Data System (ADS)

    Kosejk, Vladislav; Novy, J.; Chadzitaskos, Goce

    2015-12-01

    This paper presents an innovative telescope design based on the usage of a parabolic strip fulfilling the function of an objective. Isaac Newton was the first to solve the problem of chromatic aberration, which is caused by a difference in the refractive index of lenses. This problem was solved by a new kind of telescope with a mirror used as an objective. There are many different kinds of telescopes. The most basic one is the lens telescope. This type of a telescope uses a set of lenses. Another type is the mirror telescope, which employs the concave mirror, spherical parabolic mirror or hyperbolically shaped mirror as its objective. The lens speed depends directly on the surface of a mirror. Both types can be combined to form a telescope composed of at least two mirrors and a set of lenses. The light is reflected from the primary mirror to the secondary one and then to the lens system. This type is smaller-sized, with a respectively reduced lens speed. The telescope design presented in this paper uses a parabolic strip fulfilling the function of an objective. Observed objects are projected as lines in a picture plane. Each of the lines of a size equal to the size of the strip corresponds to the sum of intensities of the light coming perpendicular to the objective from an observed object. A series of pictures taken with a different rotation and processed by a special reconstruction algorithm is needed to get 2D pictures. The telescope can also be used for fast detection of objects. In this mode, the rotation and multiple pictures are not needed, just one picture in the focus of a mirror is required to be taken.

  1. Piecewise-parabolic methods for astrophysical fluid dynamics

    SciTech Connect

    Woodward, P.R.

    1983-11-01

    A general description of some modern numerical techniques for the simulation of astrophysical fluid flow is presented. The methods are introduced with a thorough discussion of the especially simple case of advection. Attention is focused on the piecewise-parabolic method (PPM). A description of the SLIC method for treating multifluid problems is also given. The discussion is illustrated by a number of advection and hydrodynamics test problems. Finally, a study of Kelvin-Helmholtz instability of supersonic jets using PPM with SLIC fluid interfaces is presented.

  2. Impurity binding energies in quantum dots with parabolic confinement

    NASA Astrophysics Data System (ADS)

    Abramov, Arnold

    2015-03-01

    We present an effective numerical procedure to calculate the binding energies and wave functions of the hydrogen-like impurity states in a quantum dot (QD) with parabolic confinement. The unknown wave function was expressed as an expansion over one-dimensional harmonic oscillator states, which describes the electron's movement along the defined z-axis. Green's function technique used to obtain the solution of Schredinger equation for electronic states in a transverse plane. Binding energy of impurity states is defined as poles of the wave function. The dependences of the binding energy on the position of an impurity, the size of the QD and the magnetic field strength are presented and discussed.

  3. Overview of software development at the parabolic dish test site

    NASA Technical Reports Server (NTRS)

    Miyazono, C. K.

    1985-01-01

    The development history of the data acquisition and data analysis software is discussed. The software development occurred between 1978 and 1984 in support of solar energy module testing at the Jet Propulsion Laboratory's Parabolic Dish Test Site, located within Edwards Test Station. The development went through incremental stages, starting with a simple single-user BASIC set of programs, and progressing to the relative complex multi-user FORTRAN system that was used until the termination of the project. Additional software in support of testing is discussed including software in support of a meteorological subsystem and the Test Bed Concentrator Control Console interface. Conclusions and recommendations for further development are discussed.

  4. Cauchy problems of pseudo-parabolic equations with inhomogeneous terms

    NASA Astrophysics Data System (ADS)

    Li, Zhongping; Du, Wanjuan

    2015-12-01

    This paper deals with Cauchy problems of pseudo-parabolic equations with inhomogeneous terms. The aim of the paper is to study the influence of the inhomogeneous term on the asymptotic behavior of solutions. We at first determine the critical Fujita exponent and then give the secondary critical exponent on the decay asymptotic behavior of an initial value at infinity. Furthermore, the precise estimate of life span for the blow-up solution is obtained. Our results show that the asymptotic behavior of solutions is seriously affected by the inhomogeneous term.

  5. Space–time isogeometric analysis of parabolic evolution problems

    NASA Astrophysics Data System (ADS)

    Langer, Ulrich; Moore, Stephen E.; Neumüller, Martin

    2016-07-01

    We present and analyze a new stable space-time Isogeometric Analysis (IgA) method for the numerical solution of parabolic evolution equations in fixed and moving spatial computational domains. The discrete bilinear form is elliptic on the IgA space with respect to a discrete energy norm. This property together with a corresponding boundedness property, consistency and approximation results for the IgA spaces yields an a priori discretization error estimate with respect to the discrete norm. The theoretical results are confirmed by several numerical experiments with low- and high-order IgA spaces.

  6. High versus low vancomycin serum trough regimen for Gram-positive infections: a meta-analysis.

    PubMed

    Meng, Long; Fang, Yun; Chen, Yongfei; Zhu, Huaijun; Long, Rui

    2015-08-01

    This study aimed to evaluate the impact of high vancomycin serum trough concentrations (≧15 mg/l) on clinical outcomes and nephrotoxicity among adult subjects. We searched MEDLINE, Cochrane Library, and CNKI systematically. A total of 17 studies were included. Meta-analysis found that high trough group showed no significant difference comparing to low trough group in treatment failure [relative risk (RR) 0·91, 95% confidence interval (CI) 0·67-1·24; P = 0·57] and all-cause mortality (RR 1·14, 95% CI 0·81-1·59; P = 0·46). However, the high trough concentrations were associated with lower treatment failure in bacteremia subgroup (RR 0·72, 95% CI 0·59-0·88; P = 0·001). High trough concentrations were associated with an increased risk of vancomycin-induced nephrotoxicity (RR 2·06, 95% CI 1·52-2·79; P<0·00001). Our meta-analysis indicates that high trough concentrations were not significantly superior to low trough concentrations in lowering treatment failure and mortality. Moreover, high trough concentrations significantly increased the risk of nephrotoxicity. PMID:24641266

  7. Survival of Mycobacterium avium subsp. paratuberculosis in biofilms on livestock watering trough materials.

    PubMed

    Cook, Kimberly L; Britt, Jenks S; Bolster, Carl H

    2010-02-24

    Mycobacterium avium subsp. paratuberculosis (Map) is the causative agent of Johne's disease, a chronic enteric infection that affects ruminants. Despite the ubiquitous occurrence of Mycobacterium sp. in nature and the fact that Johne's disease has been reported worldwide, little research has been done to assess its survival in agricultural environments. The goal of this 365-day study was to evaluate the ability of Map to persist in mixed-community biofilms on materials commonly used to construct livestock watering troughs. Map was inoculated into 32l of trough water containing either concrete, plastic, galvanized or stainless steel trough materials. The concentration of Map was determined by using quantitative, real-time PCR to target the IS900 sequence in DNA extracts. High concentrations of Map were detected on all trough materials after 3 days (around 1 x 10(5)cells cm(-2)). Based on the best-fit slopes, the time required for a 99% reduction (t(99)) in biofilm-associated Map cells was 144 and 115 days for plastic and stainless steel trough materials, respectively. Map concentrations did not decrease on concrete and galvanized steel trough materials. These results suggest that Map survives well in biofilms present on livestock watering trough materials. To inhibit spread of this organism and exposure of susceptible animals to Map on infected farms, best management practices aimed at maintaining biofilm-free trough surfaces should be included in any Johne's control plan. PMID:19717251

  8. Recent Observational Results of Seafloor Crustal Deformation Along the Suruga-Nankai Trough, Japan

    NASA Astrophysics Data System (ADS)

    Tadokoro, K.; Sugimoto, S.; Watanabe, T.; Muto, D.; Kimoto, A.; Okuda, T.; Ikuta, R.; Sayanagi, K.; Kuno, M.

    2008-12-01

    The Suruga-Nankai Trough is one of the active plate boundaries in the world. The Philippine Sea plate is subducting beneath the Amurian (Eurasian) plate along the tough, and major subduction earthquakes, Nankai and Tonankai earthquakes, have repeatedly occurred with intervals of about 100-150 years. The 1944 Tonankai and 1946 Nankai earthquakes are the most recent significant earthquakes along the trough. Therefore, the 50-years probabilities of the next major earthquakes are estimated at 80-90% by Headquarters for Earthquake Research Promotion, Japanese Government. It is, therefore, necessary to start monitoring crustal deformation above the source regions of the major earthquakes where in the ocean area. We developed a new system composed of the precise acoustic ranging and kinematic GPS positioning techniques for monitoring of seafloor crustal deformation [Tadokoro et al., 2006, GRL; Ikuta et al., 2008, JGR]. We had installed seven seafloor benchmarks for acoustic ranging at the Suruga-Nankai Trough region between 2002 and 2004. The water depths at the benchmarks are about 800 to 2000 m. We installed a new seafloor benchmark at the eastern margin of the Kumano Basin on June 23, 2008. Three seafloor benchmarks had been aligned perpendicular to the trough axis. In contrast, the new benchmark was installed eastward relative to the pre-installed benchmarks, and we can monitor lateral variations in crustal deformation at the region. We started the repeated measurements at four benchmarkes (two at the Kumano Basin named KMN and KMS, and the other two at the Suruga Bay named SNW and SNE) in 2005. The number of times we have measured are seven, eleven, three and nine times at KMN, KMS, SNW and SNE, respectively. Recent results of the repeated measurements show the following horizontal velocities with relative to the Amurian Plate: 6.4 cm/yr, N86W at KMN; 5.3 cm/yr, N71W at KMS; 3.3 cm/yr, N57W at SNE. The errors of the horizontal velocities are 1-3 cm/yr. Unfortunately

  9. Strain Accumulation Estimated from Seafloor Crustal Deformation at the Nankai Trough, Japan

    NASA Astrophysics Data System (ADS)

    Tadokoro, K.; Watanabe, T.; Nagai, S.; Ikuta, R.; Okuda, T.; Kenji, Y.; Sakata, T.

    2012-12-01

    the oblique subduction of the Philippine Sea Plate. We started monitoring of seafloor crustal deformation at a new site, KMC, in this year. This site is located between KMN and KMS. The monitoring at KMC enable us to depict dense (with a span of 10 km) crustal deformation profile that is related to strain accumulation, in the direction perpendicular to the trough axis. We plan to measure the position at KMC twice by the end of this year. We also continue to measure the position at KMS and KME. The number of measurements at KME is extremely few compared to the other sites in particular, and it is important to continue the measurement for obtaining stable site velocity. We report the results of monitoring preformed in this year. Acknowledgments: We are grateful to the captain and crews of R/V "Asama" of Mie Prefecture Fisheries Research Institute, Japan. This study has been partly promoted by Ministry of Education, Culture, Sports, Science and Technology, Japanese Government.

  10. The magnetisation of Rosemary Bank Seamount, Rockall Trough, northeast Atlantic

    NASA Astrophysics Data System (ADS)

    Miles, P. R.; Roberts, D. G.

    1981-08-01

    Rosemary Bank is a non-uniformly magnetised seamount in the northern Rockall Trough. The reversely magnetised major component of the anomaly field was simulated by a numerical method and modelled using the Talwani three-dimensional magnetics program. The results suggest a higher Koenigsberger ratio than earlier reported for Rosemary Bank and a remanent magnetisation vector compatible with post-Jurassic formation and probably of a Late Cretaceous to Tertiary age. The limited depth to the base of the model implies that Rosemary Bank post-dates the underlying basement in agreement with a volcanic origin. The residual of the observed anomaly field is interpreted as being caused by normally magnetised bodies within and on top of the bank. This suggests subsequent volcanic activity during an interval of normal polarity.

  11. Monitoring of seafloor crustal deformation using GPS/Acoustic technique along the Nankai Trough, Japan

    NASA Astrophysics Data System (ADS)

    Yasuda, K.; Tadokoro, K.; Ikuta, R.; Watanabe, T.; Fujii, C.; Matsuhiro, K.; Sayanagi, K.

    2014-12-01

    Seafloor crustal deformation is crucial for estimating the interplate locking at the shallow subduction zone and has been carried out at subduction margins in Japan, e.g., Japan Trench and Nankai Trough [Sato et al., 2011; Tadokoro et al., 2012]. Iinuma et al. [2012] derived slip distributions during the 2011 Tohoku-Oki earthquake using GPS/Acoustic data and on-land GPS data. The result showed that maximum slip is more than 85 m near the trench axis. The focal area along the Nankai trough extended to the trough axis affected this earthquake by cabinet office, government of Japan.  We monitored seafloor crustal deformation along the Nankai trough, Japan. Observation regions are at the eastern end of Nankai trough (named Suruga trough) and at the central Nankai trough. We established and monitored by two sites across the trough at each region. In the Suruga trough region, we repeatedly observed from 2005 to 2013. We observed 13 and 14 times at a foot wall side (SNE) and at a hanging wall side (SNW), respectively. We estimated the displacement velocities with relative to the Amurian plate from the result of repeated observation. The estimated displacement velocity vectors at SNE and SNW are 42±8 mm/y to N94±3˚W direction and 39±11 mm/y to N84±9˚W direction, respectively. The directions are the same as those measured at the on-land GPS stations. The magnitudes of velocity vector indicate significant shortening by approximately 4 mm/y between SNW and on-land GPS stations at hanging wall side of the Suruga Trough. This result shows that the plate interface at the northernmost Suruga trough is strongly locked. In the central Nankai trough region, we established new two stations across the central Nankai trough (Both stations are about 15km distance from trough) and observed only three times, August 2013, January 2014, and June 2014. We report the results of monitoring performed in this year.

  12. Control system for Parabolic Dish Concentrator No. 1

    SciTech Connect

    Stallkamp, J.A.

    1985-03-15

    This report is a description and discussion of the control system for Parabolic Dish Concentrator No. 1 (PDC-1) as used at the JPL Parabolic Dish Test Site (PDTS). The tracking action is a discontinuous, start/stop motion with sun sensors for primary control and a computed sun ephemeris for a simultaneous check and cloud passage. Project background, functional requirements, and hardware description are presented in brief form. System operation is described in considerable detail and includes the precise message exchange protocol between the module and remote control station, the initialization process, the command list, and the basic control logic used in the local microprocessor. System installation and performance items are given; the unit operated very satisfactorily for the brief period of time before it was moved to Sandia National Laboratories at Albuquerque, New Mexico. It was operated at a 0.05-deg deadband for optical characterization of the reflecting surfaces and mirror geometry. The last section includes significant presentations and discussions of (1) protection against burn by the sun in the case of failure to continue to track and (2) other equipment and personnel safety items. Operation of PDC-1 at the test site was man-attended; for extension to man-unattended operation a number of additional requirements and constraints must be identified and a full implementation of the capabilities of the design performed.

  13. Thermal storage requirements for parabolic dish solar power plants

    NASA Technical Reports Server (NTRS)

    Wen, L.; Steele, H.

    1980-01-01

    The cost effectiveness of a high temperature thermal storage system is investigated for a representative parabolic dish solar power plant. The plant supplies electrical power in accordance with a specific, seasonally varying demand profile. The solar power received by the plant is supplemented by power from fuel combustion. The cost of electricity generated by the solar power plant is calculated, using the cost of mass-producible subsystems (specifically, parabolic dishes, receivers, and power conversion units) now being designed for this type of solar plant. The trade-off between fuel and thermal storage is derived in terms of storage effectiveness, the cost of storage devices, and the cost of fuel. Thermal storage requirements, such as storage capacity, storage effectiveness, and storage cost are established based on the cost of fuel and the overall objective of minimizing the cost of the electricity produced by the system. As the cost of fuel increases at a rate faster than general inflation, thermal storage systems in the $40 to $70/kWthr range could become cost effective in the near future.

  14. Electron density profiles in the plasmasphere and trough

    NASA Astrophysics Data System (ADS)

    Laakso, H.; Masson, A.

    The plasmasphere is a manifestation of an ionospheric ion outflow that corotates with the Earth's magnetic field. This region has been studied for several decades but we still have lack of good empirical model for it. Since year 1996, the Polar satellite has passed through the inner magnetosphere more than 5,000 times, crossing the plasmapause region more than 15,000 times (sometimes four times per 18-hr orbit). Using the electron densities provided by the EFI experiment, we study statistically the density variation at L = 3-12 shells. With a power law fitting, we determine the plasmapause (PP) location and thickness, and the power law index of density slope in the plasmasphere and trough region. All characteristics reveal strong and interesting variations with MLT and Kp. The average PP location moves from L = 5 to L = 3.5 with increasing Kp. For any Kp, however, the MLT dependence is clear; both dawn- and duskside show particularly interesting activity. The PP thickness decreases with increasing Kp from 0.7 L to 0.1 L. Particularly on the nightside the plasmapause becomes very steep during increasing geomagnetic activity. On the dayside the PP thickness tends to remain always quite large (0.4-0.8 L). The trough power law index k (density is proportional to L-k) shows strong behavior with both MLT and Kp; for instance, in the post-midnight sector k decreases from 5 to 3 with increasing Kp whereas in the pre-midnight sector the change occurs between 4 and 3. Near noon k is 2.5 for all Kp conditions.

  15. Oil and gas potential of the west Kamchatka trough

    SciTech Connect

    Savostin, L.; Kusnetsov, N. )

    1993-09-01

    The west Kamchatka trough (WKT) is a region with a two-stage structural pattern (i.e., Cenozoic cover and pre-Cenozoic basement). The composition of hydrocarbons in local accumulations in the trough, and the present-day and paleotemperature distributions suggest that the hydrocarbons have a complex history. The WKT basement complexes, which have been penetrated by wells, are exposed in uplifts in the southern Median-Kamchatka ridge (MKR), where it is possible to study their composition and structure. The nappe structure of the MKR comprises various sedimentary and volcanoclastic complexes, including some highly carbonaceous Mesozoic clastics. Geodynamic analysis of the MKR rocks shows that during the Mesozoic, two separate island-arc terrances evolved in this part of the northwest Pacific, behind which a back-arc basin developed. In the Paleogene, rocks of this basin were overridden by nappes and metamorphosed. New understanding of the structure and evolution of the older complexes suggest that hydrocarbon accumulations may exist in underthrust zones in the WKT basement, which contains both reservoirs and source rocks. Subsequent evolution of the region was accompanied by the formation of zones of anomalously high formation pressure. Hydrocarbons drained upwards along faults and accumulated in structures in the cover, in places reaching the surface. Existing drilling and seismic data do not help with the interpretation of the basement structure because these operations were aimed at discovering local structural traps in the Cenozoic cover. Future oil exploration surveys in the region will require remote sensing methods that have much deeper penetration.

  16. The solvability of the first initial-boundary problem for parabolic and degenerate parabolic equations in domains with a conical point

    SciTech Connect

    Degtyarev, Sergey P

    2010-09-02

    The first initial-boundary problem for second-order parabolic and degenerate parabolic equations is investigated in a domain with a conical or angular point. The means of attack is already known and uses weighted classes of smooth or integrable functions. Sufficient conditions for a unique solution to exist and for coercive estimates for the solution to be obtained are formulated in terms of the angular measure of the solid angle and the exponent of the weight. It is also shown that if these conditions fail to hold, then the parabolic problem has elliptic properties, that is, it can have a nonzero kernel or can be nonsolvable, and, in the latter case, it is not even a Fredholm problem. A parabolic equation and an equation with some degeneracy or a singularity at a conical point are considered. Bibliography: 49 titles.

  17. Non-parabolic hydrodynamic formulations for the simulation of inhomogeneous semiconductor devices

    NASA Technical Reports Server (NTRS)

    Smith, Arlynn W.; Brennan, Kevin F.

    1995-01-01

    Hydrodynamic models are becoming prevalent design tools for small scale devices and other devices in which high energy effects can dominate transport. Most current hydrodynamic models use a parabolic band approximation to obtain fairly simple conservation equations. Interest in accounting for band structure effects in hydrodynamic device simulation has begun to grow since parabolic models can not fully describe the transport in state of the art devices due to the distribution populating non-parabolic states within the band. This paper presents two different non-parabolic formulations of the hydrodynamic model suitable for the simulation of inhomogeneous semiconductor devices. The first formulation uses the Kane dispersion relationship (hk)(exp 2)/2m = W(1 + alpha(W)). The second formulation makes use of a power law ((hk)(exp 2)/2m = xW(sup y)) for the dispersion relation. Hydrodynamic models which use the first formulation rely on the binomial expansion to obtain moment equations with closed form coefficients. This limits the energy range over which the model is valid. The power law formulation readily produces closed form coefficients similar to those obtained using the parabolic band approximation. However, the fitting parameters (x,y) are only valid over a limited energy range. The physical significance of the band non-parabolicity is discussed as well as the advantages/disadvantages and approximations of the two non-parabolic models. A companion paper describes device simulations based on the three dispersion relationships: parabolic, Kane dispersion, and power low dispersion.

  18. Non-Parabolic Hydrodynamic Formulations for the Simulation of Inhomogeneous Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Smith, A. W.; Brennan, K. F.

    1996-01-01

    Hydrodynamic models are becoming prevalent design tools for small scale devices and other devices in which high energy effects can dominate transport. Most current hydrodynamic models use a parabolic band approximation to obtain fairly simple conservation equations. Interest in accounting for band structure effects in hydrodynamic device simulation has begun to grow since parabolic models cannot fully describe the transport in state of the art devices due to the distribution populating non-parabolic states within the band. This paper presents two different non-parabolic formulations or the hydrodynamic model suitable for the simulation of inhomogeneous semiconductor devices. The first formulation uses the Kane dispersion relationship ((hk)(exp 2)/2m = W(1 + alphaW). The second formulation makes use of a power law ((hk)(exp 2)/2m = xW(exp y)) for the dispersion relation. Hydrodynamic models which use the first formulation rely on the binomial expansion to obtain moment equations with closed form coefficients. This limits the energy range over which the model is valid. The power law formulation readily produces closed form coefficients similar to those obtained using the parabolic band approximation. However, the fitting parameters (x,y) are only valid over a limited energy range. The physical significance of the band non-parabolicity is discussed as well as the advantages/disadvantages and approximations of the two non-parabolic models. A companion paper describes device simulations based on the three dispersion relationships; parabolic, Kane dispersion and power law dispersion.

  19. Classification of Invariant Differential Operators for Non-Compact Lie Algebras via Parabolic Relations

    NASA Astrophysics Data System (ADS)

    Dobrev, V. K.

    2014-05-01

    In the present paper we review the progress of the project of classification and construction of invariant differential operators for non-compact semisimple Lie groups. Our starting points is the class of algebras, which we called earlier 'conformal Lie algebras' (CLA), which have very similar properties to the conformal algebras of Minkowski space-time, though our aim is to go beyond this class in a natural way. For this we introduced recently the new notion of parabolic relation between two non-compact semisimple Lie algebras G and G' that have the same complexification and possess maximal parabolic subalgebras with the same complexification. Thus, we consider the exceptional algebra E7(7) which is parabolically related to the CLA E7(-25). Other interesting examples are the orthogonal algebras so(p, q) all of which are parabolically related to the conformal algebra so(n, 2) with p + q = n + 2, the parabolic subalgebras including the Lorentz subalgebra so(n - 1,1) and its analogs so(p - 1, q - 1). Further we consider the algebras sl(2n, Bbb R) and for n = 2k the algebras su* (4k) which are parabolically related to the CLA su(n,n). Further we consider the algebras sp(r,r) which are parabolically related to the CLA sp(2r, Bbb R). We consider also E6(6) and E6(2) which are parabolically related to the hermitian symmetric case E6(-14),

  20. Variation of the orbital elements for parabolic trajectories due to a small impulse using Gauss equations

    NASA Astrophysics Data System (ADS)

    Kamel, Osman M.; Ammar, M. K.

    2006-12-01

    Firstly we derive Gauss' perturbation equation for parabolic motion using Murray-Dermott and Kovalevsky procedures. Secondly, we easily deduce the variations of the orbital elements for the parabolic trajectories due to a small impulse at any point along the path and at the vertex of the parabola.

  1. 2008 Solar Technologies Market Report

    SciTech Connect

    Price, S.; Margolis, R.; Barbose, G.; Bartlett, J.; Cory, K.; Couture, T.; DeCesaro, J.; Denholm, P.; Drury, E.; Frickel, M.; Hemmeline, C.; Mendelsohn, T.; Ong, S.; Pak, A.; Poole, L.; Peterman, C.; Schwabe, P.; Soni, A.; Speer, B.; Wiser, R.; Zuboy, J.; James, T.

    2010-01-01

    ) Globally, about 13 GW of CSP was announced or proposed through 2015, based on forecasts made in mid-2009. Regional market shares for the 13 GW are about 51% in the United States, 33% in Spain, 8% in the Middle East and North Africa, and 8% in Australasia, Europe, and South Africa. Of the 6.5-GW project pipeline in the United States, 4.3 GW have power purchase agreements (PPAs). The PPAs comprise 41% parabolic trough, 40% power tower, and 19% dish-engine systems.

  2. Development status of the PDC-1 Parabolic Dish Concentrator

    NASA Technical Reports Server (NTRS)

    Thostesen, T.; Soczak, I. F.; Pons, R. L.

    1982-01-01

    The status of development of the 12 m diameter parabolic dish concentrator which is planned for use with the Small Community Solar Thermal Power System. The PDC-1 unit features the use of plastic reflector film bonded to structural plastic gores supported by front-bracing steel ribs. An elevation-over-azimuth mount arrangement is employed, with a conventional wheel-and-track arrangement; outboard trunnions permit the dish to be stored in the face down position, with the added advantage of easy access to the power conversion assembly. The control system is comprised of a central computer (LSI 1123), a manual control panel, a concentrator control unit, two motor controllers, a Sun sensor, and two angular position resolvers. The system is designed for the simultaneous control of several concentrators. The optical testing of reflective panels is described.

  3. A semilinear parabolic system with a free boundary

    NASA Astrophysics Data System (ADS)

    Wang, Mingxin; Zhao, Yonggang

    2015-12-01

    This paper deals with a semilinear parabolic system with reaction terms {v^p, u^q} and a free boundary {x = s(t)} in one space dimension, where {s(t)} evolves according to the free boundary condition {s'(t) = -μ(u_x + ρ v_x)}. The main aim of this paper was to study the existence, uniqueness, regularity and long-time behavior of positive solution (maximal positive solution). Firstly, we prove that this problem has a unique positive solution when {p, q ≥ 1}, and a (unique) maximal positive solution when {p < 1} or {q < 1}. Then, we study the regularity of {(u,v)} and {s}. At last, we discuss the global existence, finite-time blowup of the unique positive solution (maximal positive solution) and long-time behavior of bounded global solution.

  4. Close encounters of nearly parabolic comets and planets

    NASA Astrophysics Data System (ADS)

    Tomanov, V. P.

    2016-03-01

    An overview is given of close encounters of nearly parabolic comets (NPCs; with periods of P > 200 years and perihelion distances of q > 0.1 AU; the number of the comets is N = 1041) with planets. The minimum distances Δmin between the cometary and planetary orbits are calculated to select comets whose Δmin are less than the radius of the planet's sphere of influence. Close encounters of these comets with planets are identified by numerical integration of the comets' equations of motion over an interval of ±50 years from the time of passing the perihelion. Close encounters of NPCs with Jupiter in 1663-2011 are reported for seven comets. An encounter with Saturn is reported for comet 2004 F2 (in 2001).

  5. Optical analysis of point focus parabolic radiation concentrators

    SciTech Connect

    Bendt, P.; Rabl, A.

    1980-04-01

    A simple formalism is developed for analyzing the optical performance of point focus parabolic radiation concentrators. To account for off-axis aberrations of the parabola, an angular acceptance function is defined as that fraction of a beam of parallel radiation incident on the aperture which would reach the receiver if the optics were perfect. The radiation intercepted by the receiver of a real concentrator is obtained as a convolution of angular acceptance function, of optical error distribution, and of angular brightness distribution of the radiation source. Losses resulting from absorption in the reflector or reflection at the receiver are treated by a multiplicative factor rho ..cap alpha.. where rho = reflectance of the reflector and ..cap alpha.. = absorptance of the receiver. For numerical calculations, this method is more accurate and less time-consuming than the ray-tracing method. In many cases, there are acceptable approximations whereby the results can be obtained by reading a graph or evaluating a simple curve fit.

  6. Hypersonic flows generated by parabolic and paraboloidal shock waves

    NASA Technical Reports Server (NTRS)

    Schwartz, L. W.

    1974-01-01

    A computer algorithm has been developed to determine the blunt-body flowfields supporting symmetric parabolic and paraboloidal shock waves at infinite free-stream Mach number. Solutions are expressed in an analytic form as high-order power series, in the coordinate normal to the shock, whose coefficients can be determined exactly. Analytic continuation is provided by the use of Pade approximations. Test cases provide solutions of very high accuracy. In the axisymmetric case for gamma equals 715 the solution has been found far downstream, where it agrees with the modified blast-wave results. For plane flow, on the other hand, a limit line appears within the shock layer, a short distance past the sonic line, suggesting the presence of an imbedded shock. Local solutions in the downstream limit are discussed.

  7. Context-specific adaptation of saccade gain in parabolic flight

    NASA Technical Reports Server (NTRS)

    Shelhamer, Mark; Clendaniel, Richard A.; Roberts, Dale C.

    2002-01-01

    Previous studies established that vestibular reflexes can have two adapted states (e.g., gains) simultaneously, and that a context cue (e.g., vertical eye position) can switch between the two states. Our earlier work demonstrated this phenomenon of context-specific adaptation for saccadic eye movements: we asked for gain decrease in one context state and gain increase in another context state, and then determined if a change in the context state would invoke switching between the adapted states. Horizontal and vertical eye position and head orientation could serve, to varying degrees, as cues for switching between two different saccade gains. In the present study, we asked whether gravity magnitude could serve as a context cue: saccade adaptation was performed during parabolic flight, which provides alternating levels of gravitoinertial force (0 g and 1.8 g). Results were less robust than those from ground experiments, but established that different saccade magnitudes could be associated with different gravity levels.

  8. Two-level parabolic model with phase-jump coupling

    NASA Astrophysics Data System (ADS)

    Lehto, J. M. S.; Suominen, K.-A.

    2016-07-01

    We study the coherent dynamics of a two-level parabolic model and ways to enhance population transfer and even to obtain complete population inversion in such models. Motivated by the complete population inversion effect of zero-area pulses found in [Phys. Rev. A 73, 023416 (2006), 10.1103/PhysRevA.73.023416], we consider a scheme where a given coupling function is transformed to a zero-area coupling by performing a phase jump in the middle of the evolution. With a phase-jump coupling, complete population inversion can be achieved with relatively small coupling. In the case of Zener tunneling, complete population inversion is obtained for strong-enough coupling regardless of the height of the tunneling barrier. We also derive a universal formula for the effect of the phase jump.

  9. Parabolic dish Stirling module development and test results

    SciTech Connect

    Washom, B.

    1984-08-01

    Private industry and the U.S. Department of Energy are presently cost sharing the design, manufacture and test of a 25 Kwe parabolic dish Stirling module, known as Vanguard. The Vanguard module achieved a world's record sunlight to electric conversion efficiency of 31.6% in February 1984 at the Rancho Mirage, California test site. The module is presently operating daily in sunrise to sunset tests to determine the long term performance and O and M requirements of this distributed receiver system. Each module can be easily integrated into a larger field of modules to provide power generation opportunities from a single 25 Kwe unit for isolated loads to 30 Mwe systems for integrated utility power generation.

  10. Large Phased Array Radar Using Networked Small Parabolic Reflectors

    NASA Technical Reports Server (NTRS)

    Amoozegar, Farid

    2006-01-01

    Multifunction phased array systems with radar, telecom, and imaging applications have already been established for flat plate phased arrays of dipoles, or waveguides. In this paper the design trades and candidate options for combining the radar and telecom functions of the Deep Space Network (DSN) into a single large transmit array of small parabolic reflectors will be discussed. In particular the effect of combing the radar and telecom functions on the sizes of individual antenna apertures and the corresponding spacing between the antenna elements of the array will be analyzed. A heterogeneous architecture for the DSN large transmit array is proposed to meet the radar and telecom requirements while considering the budget, scheduling, and strategic planning constrains.

  11. Generic parabolic points are isolated in positive characteristic

    NASA Astrophysics Data System (ADS)

    Lindahl, Karl-Olof; Rivera-Letelier, Juan

    2016-05-01

    We study analytic germs in one variable with a parabolic fixed point at the origin, over an ultrametric ground field of positive characteristic. It is conjectured that for such a germ the origin is isolated as a periodic point. Our main result is an affirmative solution of this conjecture in the case of a generic germ with a prescribed multiplier. The genericity condition is explicit: the power series is minimally ramified, i.e. the degree of the first nonlinear term of each of its iterates is as small as possible. Our main technical result is a computation of the first significant terms of a minimally ramified power series. From this we obtain a lower bound for the norm of nonzero periodic points, from which we deduce our main result. As a by-product we give a new and self-contained proof of a characterization of minimally ramified power series in terms of the iterative residue.

  12. Generation of entangled matter qubits in two opposing parabolic mirrors

    NASA Astrophysics Data System (ADS)

    Trautmann, N.; Bernád, J. Z.; Sondermann, M.; Alber, G.; Sánchez-Soto, L. L.; Leuchs, G.

    2014-12-01

    We propose a scheme for the remote preparation of entangled matter qubits in free space. For this purpose, a setup of two opposing parabolic mirrors is considered, each one with a single ion trapped at its focus. To get the required entanglement in this extreme multimode scenario, we take advantage of the spontaneous decay, which is usually considered as an apparent nuisance. Using semiclassical methods, we derive an efficient photon-path representation to deal with this problem. We also present a thorough examination of the experimental feasibility of the scheme. The vulnerabilities arising in realistic implementations reduce the success probability, but leave the fidelity of the generated state unaltered. Our proposal thus allows for the generation of high-fidelity entangled matter qubits with high rate.

  13. Development status of the PDC-1 Parabolic Dish Concentrator

    NASA Astrophysics Data System (ADS)

    Thostesen, T.; Soczak, I. F.; Pons, R. L.

    1982-07-01

    The status of development of the 12 m diameter parabolic dish concentrator which is planned for use with the Small Community Solar Thermal Power System. The PDC-1 unit features the use of plastic reflector film bonded to structural plastic gores supported by front-bracing steel ribs. An elevation-over-azimuth mount arrangement is employed, with a conventional wheel-and-track arrangement; outboard trunnions permit the dish to be stored in the face down position, with the added advantage of easy access to the power conversion assembly. The control system is comprised of a central computer (LSI 1123), a manual control panel, a concentrator control unit, two motor controllers, a Sun sensor, and two angular position resolvers. The system is designed for the simultaneous control of several concentrators. The optical testing of reflective panels is described.

  14. Plasmaspheric Density Troughs: Global IMAGE EUV Observations and Analysis via Global Core Plasma Modeling

    NASA Technical Reports Server (NTRS)

    Adrian, M. L.; Gallagher, D. L.; Green, J. L.; Sandel, B. R.; Six, N. Frank (Technical Monitor)

    2002-01-01

    To date, the IMAGE EUV camera has observed several plasmaspheric density trough features inside the plasmapause under a wide range of geomagnetic activity. From the perspective of EUV, a density trough feature appears as a channel of diminished pixel counts which spans a width of L-shell (DELTA L) and magnetic local time (MLT) inside the plasmapause. Plasmaspheric density troughs are found to be morphologically complex possessing considerable spatial and temporal variability. We present an analysis of the evolution of trough DELTA L and MLT extent as functions of associated D (sub ST) and K (sub p) history. Trough features range in size from 0.16 less than or equal to DELTA L less than or equal to 1.2 with azimuthal extent from 1500 less than or equal to MLT less than or equal to 1200. All cases of plasmaspheric density troughs studied to date appear to have evolved as a result of the inner edge of the afternoon/evening plasma drainage plume being wrapped around through the nightside plasmasphere. The structure of plasmaspheric density trough features is further probed by analyzing simulated EUV images produced by forward modeling artificially introduced regions of depleted density into both static and dynamic global core plasmaspheric models. Forward modeling suggests that (1) L-shell refilling of density troughs during storm recovery can be modeled as filling from the ionosphere toward the equator (i.e., bottom-up refilling), and (2) that an erosion process is operating within flux tubes beyond the outer L-shell wall of the observed density troughs.

  15. Cerebral vasoconstriction precedes orthostatic intolerance after parabolic flight

    NASA Technical Reports Server (NTRS)

    Serrador, J. M.; Shoemaker, J. K.; Brown, T. E.; Kassam, M. S.; Bondar, R. L.; Schlegel, T. T.

    2000-01-01

    The effects of brief but repeated bouts of micro- and hypergravity on cerebrovascular responses to head-up tilt (HUT) were examined in 13 individuals after (compared to before) parabolic flight. Middle cerebral artery mean flow velocity (MCA MFV; transcranial Doppler ultrasound), eye level blood pressure (BP) and end tidal CO(2) (P(ET)CO(2)) were measured while supine and during 80 degrees HUT for 30 min or until presyncope. In the postflight tests subjects were classified as being orthostatically tolerant (OT) (n = 7) or intolerant (OI) (n = 6). BP was diminished with HUT in the OT group in both tests (p < 0.05) whereas postflight BP was not different from supine in the OI group. Postflight compared to preflight, the reduction in P(ET)CO(2) with HUT (p < 0.05) increased in both groups, although significantly so only in the OI group (p < 0.05). The OI group also had a significant decrease in supine MCA MFV postflight (p < 0.05) that was unaccompanied by a change in supine P(ET)CO(2). The decrease in MCA MFV that occurred during HUT in both groups preflight (p < 0.05) was accentuated only in the OI group postflight, particularly during the final 30 s of HUT (p < 0.05). However, this accentuated decrease in MCA MFV was not correlated to the greater decrease in P(ET)CO(2) during the same period (R = 0.20, p = 0.42). Although cerebral vascular resistance (CVR) also increased in the OI group during the last 30 s of HUT postflight (p < 0.05), the dynamic autoregulatory gain was not simultaneously changed. Therefore, we conclude that in the OI individuals, parabolic flight was associated with cerebral hypoperfusion following a paradoxical augmentation of CVR by a mechanism that was not related to changes in autoregulation nor strictly to changes in P(ET)CO(2).

  16. Relationship between trough plasma and epithelial lining fluid concentrations of voriconazole in lung transplant recipients.

    PubMed

    Heng, Siow-Chin; Snell, Gregory I; Levvey, Bronwyn; Keating, Dominic; Westall, Glen P; Williams, Trevor J; Whitford, Helen; Nation, Roger L; Slavin, Monica A; Morrissey, Orla; Kong, David C M

    2013-09-01

    Trough (predose) voriconazole concentrations in plasma and pulmonary epithelial lining fluid (ELF) of lung transplant recipients receiving oral voriconazole preemptive treatment were determined. The mean (± standard deviation [SD]) ELF/plasma ratio was 12.5 ± 6.3. A strong positive linear relationship was noted between trough plasma and ELF voriconazole concentrations (r(2) = 0.87), suggesting the feasibility of using trough plasma voriconazole concentration as a surrogate to estimate the corresponding concentration in ELF of lung transplant recipients. PMID:23817382

  17. Venus trough-and-ridge tessera - Analog to earth oceanic crust formed at spreading centers?

    NASA Technical Reports Server (NTRS)

    Head, James W.

    1990-01-01

    The similarity between the morphologies of Venus trough-and-ridge tessera and the earth's ocean floor is discussed. The hypothesis that tessera texture might be related to a crustal fabric produced at spreading centers is examined. It is suggested that the proccesses that produce the ocean floor fabric on earth are good candidates for the origin and production of the trough-and-ridge tessera. To support this hypothesis, the characteristics of the trough-and-ridge terrain in Laima Tessera are described and compared to the seafloor at spreading centers.

  18. Heat and electricity from the Sun using parabolic dish collector systems

    NASA Technical Reports Server (NTRS)

    Truscello, V. C.; Williams, A. N.

    1980-01-01

    Point focus distributed receiver solar thermal technology for the production of electric power and of industrial process heat is addressed. The thermal power systems project which emphasizes the development of cost effective systems which will accelerate the commercialization and industrialization of plants up to 10 MWe, using parabolic dish collectors is described. The projected size of the isolated load market in the 1990-2000 time period is 300 to 1000 MW/year. Although this market is small in comparison to the grid connected utility market, it is indicated that by assuming only a 20 percent market penetration, up to 10,000 power modules per year would be required to meet this need. At a production rate of 25,000 units/year and assuming no energy storage, levelized bus bar energy costs of 75 mills/kWeh are projected. These numbers are based on what is believed to be a conservative estimate regarding engine-generator conversion efficiency (40 percent) for the 1990 time period. With a more optimistic estimate of efficiency (i.e., 45 percent), the bus bar cost decreases to about 67 mills/kWeh. At very large production rates (400,000 modules/years), the costs decrease to 58 mills/kWeh. Finally, the present status of the technology development effort is discussed.

  19. Amplitude versus offset analysis to marine seismic data acquired in Nankai Trough, offshore Japan where methane hydrate exists

    NASA Astrophysics Data System (ADS)

    Hato, M.; Inamori, T.; Matsuoka, T.; Shimizu, S.

    2003-04-01

    Occurrence of methane hydrates in the Nankai Trough, located off the south-eastern coast of Japan, was confirmed by the exploratory test well drilling conducted by Japan’s Ministry of International Trade and Industry in 1999. Confirmation of methane hydrate has given so big impact to the Japan's future energy strategy and scientific and technological interest was derived from the information of the coring and logging results at the well. Following the above results, Japan National Oil Corporation (JNOC) launched the national project, named as MH21, for establishing the technology of methane hydrate exploration and related technologies such as production and development. As one of the research project for evaluating the total amount of the methane hydrate, Amplitude versus Offset (AVO) was applied to the seismic data acquired in the Nankai Trough area. The main purpose of the AVO application is to evaluate the validity of delineation of methane hydrate-bearing zones. Since methane hydrate is thought to accompany with free-gas in general just below the methane hydrate-bearing zones, the AVO has a possibility of describing the presence of free-gas. The free-gas is thought to be located just below the base of methane hydrate stability zone which is characterized by the Bottom Simulating Reflectors (BSRs) on the seismic section. In this sense, AVO technology, which was developed as gas delineation tools, can be utilized for methane hydrate exploration. The result of AVO analysis clearly shows gas-related anomaly below the BSRs. Appearance of the AVO anomaly has so wide variety. Some of the anomalies might not correspond to the free-gas existence, however, some of them may show free-gas. We are now going to develop methodology to clearly discriminate free-gas from non-gas zone by integrating various types of seismic methods such as seismic inversion and seismic attribute analysis.

  20. Cobbles in Troughs Between Meridiani Ripples (False Color)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    As NASA's Mars Exploration Rover Opportunity continues to traverse from 'Erebus Crater' toward 'Victoria Crater,' the rover navigates along exposures of bedrock between large, wind-blown ripples. Along the way, scientists have been studying fields of cobbles that sometimes appear on trough floors between ripples. They have also been studying the banding patterns seen in large ripples.

    This view, obtained by Opportunity's panoramic camera on the rover's 802nd Martian day (sol) of exploration (April 27, 2006), is a mosaic spanning about 30 degrees. It shows a field of cobbles nestled among wind-driven ripples that are about 20 centimeters (8 inches) high.

    The origin of cobble fields like this one is unknown. The cobbles may be a lag of coarser material left behind from one or more soil deposits whose finer particles have blown away. The cobbles may be eroded fragments of meteoritic material, secondary ejecta of Mars rock thrown here from craters elsewhere on the surface, weathering remnants of locally-derived bedrock, or a mixture of these. Scientists will use the panoramic camera's multiple filters to study the rock types, variability and origins of the cobbles.

    This is a false-color rendering that combines separate images taken through the panoramic camera's 753-nanometer, 535-nanometer and 432-nanometer filters. The false color is used to enhance differences between types of materials in the rocks and soil.

  1. Load on Trough Bellows Following an Argon Spill

    SciTech Connect

    Chess, K.; /Fermilab

    1988-07-12

    In the case of a gross argon spill from the DO detector, the liquid argon is caught in three plenums. These plenums are to be connected by bellows to make a horizontal trough open at one end for removing the argon. The design of these bellows is dependent on the maximum argon load they must carry. Bellows to connect the three argon-catching plenums in the DO detector must be able to carry at least 92 lbs of argon when closed and 231 lbs when open, plus the load due to argon in the convolutions. Examples of such loads and the method for their calculations are contained in the Discussion. It should be noted that a set of assumptions was used in these calculations. First, we considered a uniform channel and uniform flow. Second, we used a value for Manning's n meant for a similar, but not exactly the same, case. Finally, we were forced to define an average depth, d, to be used to state the hydraulic radius, R, and area of flow, A. These facts may warrant consideration in future calculations.

  2. Wouthuysen-Field absorption trough in cosmic string wakes

    NASA Astrophysics Data System (ADS)

    Hernández, Oscar F.

    2014-12-01

    The baryon density enhancement in cosmic string wakes leads to a stronger coupling of the spin temperature to the gas kinetic temperate inside these string wakes than in the intergalactic medium (IGM). The Wouthuysen-Field (WF) effect has the potential to enhance this coupling to such an extent that it may result in the strongest and cleanest cosmic string signature in the currently planned radio telescope projects. Here we consider this enhancement under the assumption that x-ray heating is not significant. We show that the size of this effect in a cosmic string wake leads to a brightness temperature at least two times more negative than in the surrounding IGM. If the SCI-HI [T. C. Voytek et al., Astrophys. J. 782, L9 (2014), J. B. Peterson et al., arXiv:1409.2774] or EDGES [J. D. Bowman and A. E. E. Rogers Nature (London) 468, 796 (2010), J. D. Bowman et al., Astrophys. J. 676, 1 (2008)] experiments confirm a WF absorption trough in the cosmic gas, then cosmic string wakes should appear clearly in 21 cm redshift surveys of z =10 to 30.

  3. Lower Permian Dry Mountain trough, eastern Nevada: preliminary basin analysis

    SciTech Connect

    Schwarz, D.L.; Snyder, W.S.; Spinosa, C.

    1987-08-01

    The Lower Permian Dry Mountain trough (DMT) is one of several basins that developed during the Late Pennsylvanian to Permian along the western edge of the North American continent. A tectonic mechanism has been suggested for the subsidence of the DMT, possibly due to reactivation of the Antler orogenic belt during the waning stages of Ancestral Rocky Mountain deformation. The DMT records marked subsidence with the appearance during the Artinskian (latest Wolfcampian) of a deeper water facies that consists of thin-bedded silty micrites and micritic mudstones rich in radiolarians and sponge spicules, characterized by a relative abundance of ammonoids, and rarer conodonts and Nereites ichnofacies trace fossils. Taxa recovered from a distinctive concretionary horizon at various locations provide an Artinskian datum on which to palinspastically reconstruct the DMT paleogeography. These taxa include ammonoids: Uraloceras, Medlicottia, Marathonites, Crimites, Metalegoceras, properrinitids; and conodonts: Neogondolella bisselli, Sweetognathus whitei, S. behnkeni, and Diplognathodus stevensi. The western margin facies of the DMT consists of Permian Carbon Ridge/Garden Valley Formations. Here, lowermost black Artinskianage euxinic micrites, considered a potential source rock for petroleum generation, are overlain by base-of-slope carbonate apron deposits, which, in turn, are overlain by base-of-slope carbonate apron deposits, which, in turn, are overlain by a thick, eastwardly prograding conglomerate wedge. Seismic profiles across Diamond Valley indicate a 3.0-4.6-km thick Tertiary sequence above the Paleozoic strata.

  4. Propagation of hypergeometric laser beams in a medium with a parabolic refractive index

    NASA Astrophysics Data System (ADS)

    Kotlyar, V. V.; Kovalev, A. A.; Nalimov, A. G.

    2013-12-01

    An expression to describe the complex amplitude of a family of paraxial hypergeometric laser beams propagating in a parabolic-index fiber is proposed. A particular case of a Gaussian optical vortex propagating in a parabolic-index fiber is studied. Under definite parameters, the Gaussian optical vortices become the modes of the medium. This is a new family of paraxial modes derived for the parabolic-index medium. A wide class of solutions of nonparaxial Helmholtz equations that describe modes in a parabolic refractive index medium is derived in the cylindrical coordinate system. As the solutions derived are proportional to Kummer’s functions, only those of them which are coincident with the nonparaxial Laguerre-Gaussian modes possess a finite energy, meaning that they are physically implementable. A definite length of the graded-index fiber is treated as a parabolic lens, and expressions for the numerical aperture and the focal spot size are deduced. An explicit expression for the radii of the rings of a binary lens approximating a parabolic-index lens is derived. Finite-difference time-domain simulation has shown that using a binary parabolic-index microlens with a refractive index of 1.5, a linearly polarized Gaussian beam can be focused into an elliptic focal spot which is almost devoid of side-lobes and has a smaller full width at half maximum diameter of 0.45 of the incident wavelength.

  5. Boundedness and global existence in the higher-dimensional parabolic-parabolic chemotaxis system with/without growth source

    NASA Astrophysics Data System (ADS)

    Xiang, Tian

    2015-06-01

    In this paper, we are concerned with a general class of quasilinear parabolic-parabolic chemotaxis systems with/without growth source, under homogeneous Neumann boundary conditions in a smooth bounded domain Ω ⊂Rn with n ≥ 2. It is recently known that blowup is possible even in the presence of superlinear growth restrictions. Here, we derive new and interesting characterizations on the growth versus the boundedness. We show that the hard task of proving the L∞-boundedness of the cell density can be reduced to proving its Lr-boundedness. In other words, we show that the Lr-boundedness of the cell density can successfully guarantee its L∞-boundedness and hence its global boundedness, where r = n + ɛ or n/2 + ɛ depending on whether the growth restriction is essentially linear (including no growth) or superlinear. Hence, a blowup solution also blows up in Lp-norm for any suitably large p. More detailed information on how the growth source affects the boundedness of the solution is derived. These results reveal deep understandings of blowup mechanism for chemotaxis models. Then we use these criteria to establish uniform boundedness and hence global existence of the underlying models: logistic source in 2-D, cubic source as initially proposed by Mimura and Tsujikawa in 3-D, [ (n - 1) + ɛ ]st source in n-D with n ≥ 4. As a consequence, in a chemotaxis-growth model, blowup is impossible if the growth effect is suitably strong. Finally, we underline that our results remove the commonly assumed convexity on the domain Ω.

  6. Invariant differential operators for non-compact Lie algebras parabolically related to conformal Lie algebras

    NASA Astrophysics Data System (ADS)

    Dobrev, V. K.

    2013-02-01

    In the present paper we continue the project of systematic construction of invariant differential operators for non-compact semisimple Lie groups. Our starting points is the class of algebras, which we call 'conformal Lie algebras' (CLA), which have very similar properties to the conformal algebras of Minkowski space-time, though our aim is to go beyond this class in a natural way. For this we introduce the new notion of parabolic relation between two non-compact semisimple Lie algebras G and G ' that have the same complexification and possess maximal parabolic subalgebras with the same complexification. Thus, we consider the exceptional algebra E 7(7) which is parabolically related to the CLA E 7(-25) , the parabolic subalgebras including E 6(6) and E 6(-26). Other interesting examples are the orthogonal algebras so(p, q) all of which are parabolically related to the conformal algebra so( n, 2) with p + q = n + 2, the parabolic subalgebras including the Lorentz subalgebra so( n - 1, 1) and its analogs so( p - 1, q - 1). We consider also E6(6) and E6(2) which are parabolically related to the hermitian symmetric case E6(-14) , the parabolic subalgebras including real forms of sl(6). We also give a formula for the number of representations in the main multiplets valid for CLAs and all algebras that are parabolically related to them. In all considered cases we give the main multiplets of indecomposable elementary representations including the necessary data for all relevant invariant differential operators. In the case of so( p, q) we give also the reduced multiplets. We should stress that the multiplets are given in the most economic way in pairs of shadow fields. Furthermore we should stress that the classification of all invariant differential operators includes as special cases all possible conservation laws and conserved currents, unitary or not.

  7. Overview of Holocene Tsunami Deposits along the Nankai, Suruga, and Sagami Troughs, Southwest Japan

    NASA Astrophysics Data System (ADS)

    Komatsubara, Junko; Fujiwara, Osamu

    2007-03-01

    Tsunami deposits provide a basis for reconstructing Holocene histories of great earthquakes and tsunamis on the Pacific Coast of southwest Japan. The deposits have been found in the past 15 years at lakes, lagoons, outcrops, and archaeological excavations. The inferred tsunami histories span 3000 years for the Nankai and Suruga Troughs and nearly 10,000 years for the Sagami Trough. The inferred histories contain recurrence intervals of variable length. The shortest of these —100 200 years for the Nankai Trough, 150 300 years for the Sagami Trough — resemble those known from written history of the past 1000 1500 years. Longer intervals inferred from the tsunami deposits probably reflect variability in rupture mode, incompleteness of geologic records, and insufficient research. The region's tsunami history could be clarified by improving the geologic distinction between tsunami and storm, dating the inferred tsunamis more accurately and precisely, and using the deposits to help quantify the source areas and sizes of the parent earthquakes.

  8. A Parabolic Equation Approach to Modeling Acousto-Gravity Waves for Local Helioseismology

    NASA Astrophysics Data System (ADS)

    Del Bene, Kevin; Lingevitch, Joseph; Doschek, George

    2016-08-01

    A wide-angle parabolic-wave-equation algorithm is developed and validated for local-helioseismic wave propagation. The parabolic equation is derived from a factorization of the linearized acousto-gravity wave equation. We apply the parabolic-wave equation to modeling acoustic propagation in a plane-parallel waveguide with physical properties derived from helioseismic data. The wavenumber power spectrum and wave-packet arrival-time structure for receivers in the photosphere with separation up to 30° is computed, and good agreement is demonstrated with measured values and a reference spectral model.

  9. A Parabolic Equation Approach to Modeling Acousto-Gravity Waves for Local Helioseismology

    NASA Astrophysics Data System (ADS)

    Del Bene, Kevin; Lingevitch, Joseph; Doschek, George

    2016-07-01

    A wide-angle parabolic-wave-equation algorithm is developed and validated for local-helioseismic wave propagation. The parabolic equation is derived from a factorization of the linearized acousto-gravity wave equation. We apply the parabolic-wave equation to modeling acoustic propagation in a plane-parallel waveguide with physical properties derived from helioseismic data. The wavenumber power spectrum and wave-packet arrival-time structure for receivers in the photosphere with separation up to 30° is computed, and good agreement is demonstrated with measured values and a reference spectral model.

  10. Calibration Shots Recorded for the Salton Seismic Imaging Project, Salton Trough, California

    NASA Astrophysics Data System (ADS)

    Murphy, J. M.; Rymer, M. J.; Fuis, G. S.; Stock, J. M.; Goldman, M.; Sickler, R. R.; Miller, S. A.; Criley, C. J.; Ricketts, J. W.; Hole, J. A.

    2009-12-01

    The Salton Seismic Imaging Project (SSIP) is a collaborative venture between the U.S. Geological Survey, California Institute of Technology, and Virginia Polytechnic Institute and State University, to acquire seismic reflection/wide angle refraction data, and currently is scheduled for data acquisition in 2010. The purpose of the project is to get a detailed subsurface 3-D image of the structure of the Salton Trough (including both the Coachella and Imperial Valleys) that can be used for earthquake hazards analysis, geothermal studies, and studies of the transition from ocean-ocean to continent-continent plate-boundary. In June 2009, a series of calibration shots were detonated in the southern Imperial Valley with specific goals in mind. First, these shots were used to measure peak particle velocity and acceleration at various distances from the shots. Second, the shots were used to calibrate the propagation of energy through sediments of the Imperial Valley. Third, the shots were used to test the effects of seismic energy on buried clay drainage pipes, which are abundant throughout the irrigated parts of the Salton Trough. Fourth, we tested the ODEX drilling technique, which uses a down-hole casing hammer for a tight casing fit. Information obtained from the calibration shots will be used for final planning of the main project. The shots were located in an unused field adjacent to Hwy 7, about 6 km north of the U.S. /Mexican border (about 18 km southeast of El Centro). Three closely spaced shot points (16 meters apart) were aligned N-S and drilled to 21-m, 23.5-m, and 27-m depth. The holes were filled with 23-kg, 68-kg, and 123-kg of ammonium-nitrate explosive, respectively. Four instrument types were used to record the seismic energy - six RefTek RT130 6-channel recorders with a 3-component accelerometer and a 3-component 2-Hz velocity sensor, seven RefTek RT130 3-channel recorders with a 3-component 4.5-Hz velocity sensor, 35 Texans with a vertical component 4

  11. The spiral troughs of Mars North Polar Layered Deposits as Cyclic Steps

    NASA Astrophysics Data System (ADS)

    Smith, Isaac; Spiga, Aymeric; Holt, John

    2014-05-01

    The spiral troughs of Mars North Polar Layered Deposits [NPLD] are intriguing features that dominate the polar landscape. Because the stratigraphy of the NPLD is related to deposition of ice and dust, the layers of the NPLD act as a geologic record to recent Martian climate, potentially useful for understanding global processes and validating Global Circulation Models [GCMs]. Stratigraphy related to the spiral troughs is exceptionally rich and offers more variability than lower, subhorizontal layers, so determining the processes controlling trough formation and evolution is an important step in understanding the history of ice and climate on Mars. However, the mechanism behind trough initiation has remained a puzzle. Recent studies of subsurface stratigraphy and low altitude clouds have indicated that the troughs formation and evolution is intricately tied to atmospheric processes, especially katabatic winds and asymmetric ice accumulation. We utilize stratigraphy collected by the Shallow Radar instrument (SHARAD) on Mars Reconnaissance Orbiter to examine accumulation of layers that record trough evolution and constrain lateral transport of ice. We then employ simulated wind fields from the Laboratoire de Météorologie Dynamique GCM and mesoscale models to calculate Froude numbers associated with katabatic flow. These simulations predict flows that experience katabatic jumps at numerous spiral troughs. Katabatic jumps are the aeolian counterpart of hydraulic jumps in open channel flow and are prominent on Mars near the poles. Next, we present visible images from the Thermal Emission Imaging System (THEMIS) and other optical spectrum instruments to observe low altitude clouds that we interpret as visible indications of katabatic jumps. These clouds potentially serve as mechanisms of deposition. Finally, we devise a theoretical framework for understanding the origin of the spiral troughs in a Froude supercritical cyclic step model. Cyclic steps are quasi

  12. Volcanism and massive sulfide formation at a sedimented spreading center, Escanaba Trough, Gorda Ridge, northeast Pacific.

    USGS Publications Warehouse

    Morton, J.L.; Holmes, M.L.; Koski, R.A.

    1987-01-01

    Seismic-reflection profiles over the sediment-filled Escanaba Trough at the southern Gorda Ridge reveal a series of volcanic centers that pierce the sediment. The volcanic edifices are 3 to 6 km in diameter and are spaced at 15 to 20 km intervals along the axis of the trough. Composition and form of sulfide samples obtained from the bank suggest significant interaction between hydrothermal fluids and sediment at depth, and deposition of sulfide within the sediment pile.-from Authors

  13. Biosignal alterations generated by parabolic flights of small aerobatic aircrafts

    NASA Astrophysics Data System (ADS)

    Simon, M. Jose; Perez-Poch, Antoni; Ruiz, Xavier; Gavalda, Fina; Saez, Nuria

    Since the pioneering works of Prof. Strughold in 1948, the aerospace medicine aimed to characterize the modifications induced in the human body by changes in the gravity level. In this respect, it is nowadays well known that one of the most serious problems of these kind of environments is the fluid shift. If this effect is enough severe and persistent, serious changes in the hemodynamic of the brain (cerebral blood flow and blood oxigenation level) appear which could be detected as alterations in the electroencephalogram, EEG [1]. Also, this fluid redistribution, together with the relocation of the heart in the thorax, induces detectable changes in the electrocardiogram, ECG [2]. Other kind of important problems are related with vestibular instability, kinetosis and illusory sensations. In particular since the seventies [3,4] it is known that in parabolic flights and due to eye movements triggered by the changing input from the otholith system, fixed real targets appeared to have moved downward while visual afterimages appeared to have moved upward (oculogravic illusions). In order to cover all the above-mentioned potential alterations, the present work, together with the gravity level, continuously monitors the electroencephalogram, EEG, the electrocardiogram, ECG and the electrooculogram, EOG of a normal subject trying to detect correlations between the different alterations observed in these signals and the changes of gravity during parabolic flights. The small aerobatic aircraft used is a CAP10B and during the flight the subject is located near the pilot. To properly cover all the range of accelerations we have used two sensitive triaxial accelerometers covering the high and low ranges of acceleration. Biosignals have been gathered using a Biopac data unit together with the Acknowledge software package (from BionicÔ). It is important to finally remark that, due to the obvious difference between the power of the different engines, the accelerometric

  14. Gravity Inversion with Geological Modeling Constraint and Its Application in the Okinawa Trough

    NASA Astrophysics Data System (ADS)

    Zhang, S.

    2014-12-01

    The satellite altimetry gravity data is used to recover the 3D distribution of oceanic lithosphere density in the Okinawa Trough and its neighbor region. It's difficult to use only gravity data to invert complex geological structure and density distribution by 3D gravity Inversion method. In order to improve the vertical resolution of the density inversion result, 3D geological modeling method is used to build structural model for the inversion, prior constraint conditions can be applied to solve the non-unique problem. In the Okinawa Trough, it is proved by earthquake data that the Philippine plate dives beneath the Okinawa Trough, which result in the upwelling of mantel material and decrease of the crust thickness. The Benioff zone clearly shows the plate's subduction parameter, such as direction, dip, transformation. Therefore, a structural subduction model is created by geological modeling method and works as the initial model and as constraint condition in gravity inversion. The 3D gravity inversion result and seismology CMT data are both used to explain the oceanic lithosphere structure in the Okinawa Trough. The inversion result illustrates high density anomaly under the Okinawa Trough. Affected by small scale mantle convections, the continental lithosphere is separated, which result in the spreading of back-arc basin and the formation of the Okinawa Trough.

  15. Modeling the double-trough structure observed in broad absorption line QSOs using radiative acceleration

    NASA Technical Reports Server (NTRS)

    Arav, Nahum; Begelman, Mitchell C.

    1994-01-01

    We present a model explaining the double trough, separated by delta v approximately = 5900 km/s, observed in the C IV lambda-1549 broad absorption line (BAL) in a number of BALQSOs. The model is based on radiative acceleration of the BAL outflow, and the troughs result from modulations in the radiative force. Specifically, where the strong flux from the Lyman-alpha lambda-1215 broad emission line is redshifted to the frequency of the N V lambda-1240 resonance line, in the rest frame of the accelerating N V ions, the acceleration increases and the absorption is reduced. At higher velocities the Lyman-alpha emission is redshifted out of the resonance and the N V ions experience a declining flux which causes the second absorption trough. A strongly nonlinear relationship between changes in the flux and the optical depth in the lines is shown to amplify the expected effect. This model produces double troughs for which the shallowest absorption between the two troughs occurs at v approximately = 5900 km/s. Indeed, we find that a substantial number of the observed objects show this feature. A prediction of the model is that all BALQSOs that show a double-trough signature will be found to have an intrinsic sharp drop in their spectra shortward of approximately 1200 A.

  16. Temporal variations in the dawn and dusk midlatitude trough position-modeled and measured (Ariel 3)

    NASA Technical Reports Server (NTRS)

    Grebowsky, J. M.; Tulunay, Y. K.; Chen, A. J.

    1973-01-01

    The temporal development of the latitudinal position of the 600 km midlatitude electron density trough at dawn and dusk during the period 25-27 May 1967, which encompassed a large magnetic storm, was measured by the RF capacitive probe on the polar orbiting Ariel 3 satellite. The substorm-related changes in the L coordinate of the trough minimum and the point of most rapid change of density gradient on the low latitude side of the trough are similar. Oscillations of the trough position at dusk are in phase with substorm activity whereas movement of the trough at dawn is only apparent with the onset of the large storm. Near dusk there is evidence of structure in the form of a tail-like extension of the plasmasphere at the peak of the storm. Detailed model calculations assuming a spatially invariant equatorial convection E field which varies in step with K sub p index reproduces much of the observed behavior, particularly at dusk, and shows that more than one plasmapause-type transition may be identifiable in the trough region.

  17. Pennsylvanian-Permian tectonism in the Great Basin: The Dry Mountain trough and related basins

    SciTech Connect

    Snyder, W.S.; Spinosa, C.; Gallegos, D.M. )

    1991-02-01

    Pennsylvanian-Permian tectonism affected the continental margin of western North America from the Yukon to the Mojave Desert. Specific signatures of this tectonism include local angular unconformities, regional disconformities, renewed outpouring of clastic debris from a reactivated Antler and related highlands, and development of deeper water basins with anoxic sediments deposited below wave base. The basins formed include Ishbel trough (Canada), the Wood River basin (Idaho), Cassia basin, Ferguson trough, Dry Mountain trough (all Nevada), and unnamed basins in Death Valley-Mojave Desert region. The Dry Mountain trough (DMT) was initiated during early Wolfcampian and received up to 1,200 m of sediment by the late Leonardian. The lower contact is a regional unconformity with the Ely Limestone, or locally with the Diamond Peak or Vinini formations. Thus, following a period of localized regional uplift that destroyed the Ely basin, portions of the uplifted and exposed shelf subsided creating the Dry Mountain trough. Evidence suggesting a tectonic origin for the DMT includes (1) high subsidence rates (60-140 m/m.y.); (2) renewed influx of coarse clastic debris from the Antler highlands: (3) possible pre-Early Permian folding, thrusting, and tilting within the highlands; and (4) differential subsidence within the Dry Mountain trough, suggesting the existence of independent fault blocks.

  18. Microearthquakes and Crustal Structures in the Southern Okinawa Trough

    NASA Astrophysics Data System (ADS)

    Lin, J.; Sibuet, J.; Lee, C.; Hsu, S.; Klingelhoefer, F.; Auffret, Y.; Pelleau, P.; Crozon, J.

    2004-12-01

    Located east of Taiwan, the southern Okinawa Trough (SOT) is a portion of a young continental backarc basin, which is still in the rifting stage. Based on seismicity data, a slab tear was identified along 123.3°E. In order to better understand the nature and role of tectonic features in this region, a passive seismic Ocean Bottom Seismometer (OBS) experiment was conducted from November 19 to December 1, 2003. 15 OBSs were deployed in a 130 x 90 km area including the Ryukyu slab tear and the Cross Backarc Volcanic Trail (CBVT). OBSs with three 4.5 Hz component geophones and an hydrophone recorded about 4000 microearthquakes. Most of them (about 94%) are crustal earthquakes (0-20 km) which occured in the SOT central graben. Just a few earthquakes were recorded from the upper slope of the northern SOT and from the Ryukyu forearc. Most of the earthquake local magnitudes (ML) range from 1 to 2, even if the whole range of magnitudes spans from 0.9 to 4. Three clusters of high microearthquake activity are observed in : (1) the CBVT area (24.7-25°N; 122.5-123°E); (2) the southern central graben area (24.65-24.85°N;123-123.3°E); and (3) the northern central graben area (24.9-25.2°N ;123.2-123.65°E). The southern central graben cluster is also identified by the Japan Meteorological Agency (JMA). The earthquakes determined by the JMA in the northern central graben present larger magnitudes than ours, but are globally located 10-km south of our cluster. The CBVT cluster is not recorded in JMA data probably because the shallow (O-5 km) volcanic activity only involved small earthquakes which are too far from the JMA's network. Based on swath bathymetric and seismic data, most of the epicenters lie along already identified normal faults. Thus, except the volcanic activity, which occurs in the CBVT area, the main factor controlling the SOT tectonic activity is normal faulting. On the northern and southern slopes of the central graben, hypocenters occur along normal fauls

  19. Nonlocal operators, parabolic-type equations, and ultrametric random walks

    SciTech Connect

    Chacón-Cortes, L. F. Zúñiga-Galindo, W. A.

    2013-11-15

    In this article, we introduce a new type of nonlocal operators and study the Cauchy problem for certain parabolic-type pseudodifferential equations naturally associated to these operators. Some of these equations are the p-adic master equations of certain models of complex systems introduced by Avetisov, V. A. and Bikulov, A. Kh., “On the ultrametricity of the fluctuation dynamicmobility of protein molecules,” Proc. Steklov Inst. Math. 265(1), 75–81 (2009) [Tr. Mat. Inst. Steklova 265, 82–89 (2009) (Izbrannye Voprosy Matematicheskoy Fiziki i p-adicheskogo Analiza) (in Russian)]; Avetisov, V. A., Bikulov, A. Kh., and Zubarev, A. P., “First passage time distribution and the number of returns for ultrametric random walks,” J. Phys. A 42(8), 085003 (2009); Avetisov, V. A., Bikulov, A. Kh., and Osipov, V. A., “p-adic models of ultrametric diffusion in the conformational dynamics of macromolecules,” Proc. Steklov Inst. Math. 245(2), 48–57 (2004) [Tr. Mat. Inst. Steklova 245, 55–64 (2004) (Izbrannye Voprosy Matematicheskoy Fiziki i p-adicheskogo Analiza) (in Russian)]; Avetisov, V. A., Bikulov, A. Kh., and Osipov, V. A., “p-adic description of characteristic relaxation in complex systems,” J. Phys. A 36(15), 4239–4246 (2003); Avetisov, V. A., Bikulov, A. H., Kozyrev, S. V., and Osipov, V. A., “p-adic models of ultrametric diffusion constrained by hierarchical energy landscapes,” J. Phys. A 35(2), 177–189 (2002); Avetisov, V. A., Bikulov, A. Kh., and Kozyrev, S. V., “Description of logarithmic relaxation by a model of a hierarchical random walk,” Dokl. Akad. Nauk 368(2), 164–167 (1999) (in Russian). The fundamental solutions of these parabolic-type equations are transition functions of random walks on the n-dimensional vector space over the field of p-adic numbers. We study some properties of these random walks, including the first passage time.

  20. Seismic Reflectivity of the Crust in the Northern Salton Trough

    NASA Astrophysics Data System (ADS)

    Bauer, K.; Fuis, G. S.; Goldman, M.; Persaud, P.; Ryberg, T.; Langenheim, V. E.; Scheirer, D. S.; Rymer, M. J.; Hole, J. A.; Stock, J. M.; Catchings, R.

    2015-12-01

    The Salton Trough in southern California is a tectonically active pull-apart basin that was formed by migrating step-overs between strike-slip faults, of which the San Andreas Fault (SAF) and the Imperial Fault are the current, northernmost examples. The Salton Seismic Imaging Project (SSIP) was undertaken to improve our knowledge of fault geometry and seismic velocities within the sedimentary basins and underlying crystalline crust around the SAF. Such data are useful as input for modeling scenarios of strong ground shaking in the surrounding high-population areas. We used pre-stack depth migration of line segments from shot gathers in several seismic profiles that were acquired in the northern part of the SSIP study area (Lines 4 - 7). Our migration approach can be considered as an infinite-frequency approximation of the Fresnel volume pre-stack depth migration method. We use line segments instead of the original waveform data. We demonstrate the method using synthetic data and analyze real data from Lines 4 - 7 to illustrate the relationship between distinct phases in the time domain and their resulting image at depth. We show both normal-moveout reflections from sub-horizontal interfaces and reverse-moveout reflections from steep interfaces, such as faults. Migrated images of dipping faults, such as the SAF and the Pinto Mountain Fault, are presented in this way. The SAF is imaged along Line 4, through the Mecca Hills, as a number of steeply dipping fault segments that collectively form a flower structure, above 5 km depth, that sole into a moderately NE-dipping fault below that depth. The individual migrated reflection packages correlate with mapped surface fault traces in the Mecca Hills. A similar geometry is seen on Line 6, from Palm Springs through Yucca Valley, where fault splays sole or project into a moderately dipping SAF below 10-km depth. We also show and discuss the reflectivity pattern of the middle and lower crust for Lines 4 - 7.

  1. Modeling the tor-dotted crests, bedrock edges, and parabolic profiles of high alpine surfaces of the Wind River Range, Wyoming

    NASA Astrophysics Data System (ADS)

    Anderson, Robert S.

    2002-07-01

    particular, the steeper the initial landscape, the more likely tors are to develop, as the high curvature disallows accumulation of regolith. These tors, in turn, limit the lowering rate of the crest, and the landscape retains significant local relief. Low relief initial conditions more likely lead to parabolic surfaces that lack tors. That tors are more likely on the crests reflects the high initial curvature at the crest. Tors on the side slopes are eliminated. The present high surfaces in the Laramide ranges of the western USA imply operation of periglacial surface processes over millions of years. The occasional tors imply a steeper rather than flatter initial landscape. The strong decoupling of surfaces from glacial troughs justifies their use as local geomorphic markers that allow calculation of relief production since glacial incision was initiated. On the other hand, their present low curvature does not require a landscape history in which these surfaces were once joined as an initially widespread erosion surface.

  2. On a regular problem for an elliptic-parabolic equation with a potential boundary condition

    NASA Astrophysics Data System (ADS)

    Arepova, Gauhar

    2016-08-01

    In this paper, we construct a lateral boundary condition for an elliptic-parabolic equation in a finite domain. Theorem on existence and uniqueness of a solution of the considered problem is proved by method of theory potential.

  3. A position transducer for studying parabolic motion and rolling down a grooved track

    NASA Astrophysics Data System (ADS)

    Basta, M.; Di Gennaro, M.; Picciarelli, V.

    1994-09-01

    We describe a computerized system based on a position transducer on-line and discuss its applications in two experiments (parabolic motion and rolling down a grooved track) performed in an introductory physics laboratory course.

  4. Hormonal responses of metoclopramide-treated subjects experiencing nausea or emesis during parabolic flight

    NASA Technical Reports Server (NTRS)

    Kohl, Randall L.

    1987-01-01

    The concentrations of adrenocorticotropic hormone (ACTH), vasopressin (AVP), epinephrine (EPI), and norepinephrine (NE) in 22 subjects administered 10 to 20 mg of metoclopramide prior to parabolic flight are measured. The effect of metoclopramide on motion sickness is examined. It is observed that metoclopramide is ineffective in the modulation of motion sickness due to stressful linear and angular acceleration and orbital flight, and it does not affect serum hormones prior to parabolic flight. It is detected that the serum level of AVP declines following emesis induced by parabolic flight and stressful angular acceleration; the serum levels of ACTH and EPI are elevated by parabolic flight and stressful angular acceleration; and serum NE is significantly elevated immediately following emesis. The possible roles of these hormones in the etiology of space motion sickness are discussed.

  5. Generalized Directional Gradients, Backward Stochastic Differential Equations and Mild Solutions of Semilinear Parabolic Equations

    SciTech Connect

    Fuhrman, Marco Tessitore, Gianmario

    2005-05-15

    We study a forward-backward system of stochastic differential equations in an infinite-dimensional framework and its relationships with a semilinear parabolic differential equation on a Hilbert space, in the spirit of the approach of Pardoux-Peng. We prove that the stochastic system allows us to construct a unique solution of the parabolic equation in a suitable class of locally Lipschitz real functions. The parabolic equation is understood in a mild sense which requires the notion of a generalized directional gradient, that we introduce by a probabilistic approach and prove to exist for locally Lipschitz functions.The use of the generalized directional gradient allows us to cover various applications to option pricing problems and to optimal stochastic control problems (including control of delay equations and reaction-diffusion equations),where the lack of differentiability of the coefficients precludes differentiability of solutions to the associated parabolic equations of Black-Scholes or Hamilton-Jacobi-Bellman type.

  6. Protocol versus Nonprotocol Dosing of Vancomycin in Neonates: A Single Center Evaluation of Steady State Trough Levels.

    PubMed

    Schwartz, Megan L; Wrobel, Joanna; Huntley, Jamalee; Zeilmann, Carla

    2016-06-01

    Objective This study aims to assess the need for modification of the current vancomycin dosing protocol at a single institution by conducting a comparison of dosing per protocol versus off protocol and the resulting first troughs in neonates. Secondary outcomes include comparison of time to first therapeutic steady-state trough, dose at first therapeutic steady-state trough, and success of the consult-to-pharmacy service. Study Design This single center retrospective chart review analyzed patients at a level-IIIb neonatal intensive care unit who received vancomycin and had at least one appropriately drawn trough level documented from 2013 to 2014. Effectiveness of each dosing strategy was evaluated by assessing troughs. Results Approximately 30% of first vancomycin trough levels obtained are within the desired range of 15 to 20 µg/mL and patients achieve therapeutic steady-state trough levels after 3.6 days, regardless of the initial dosing strategy. The current protocol reflects the therapeutic steady state dosing only 22% of the time. The vancomycin consult-to-pharmacy service improves the achievement of goal trough ranges. Conclusion An assessment of doses that achieved a goal vancomycin trough of 15 to 20 µg/mL revealed that a dose of 12.5 mg/kg at the same intervals and age ranges specified in the current protocol would enable the achievement of this higher goal trough. PMID:26862722

  7. High Speed Analysis Of Free Flights With A Parabolic Thruster

    NASA Astrophysics Data System (ADS)

    Scharring, Stefan; Eckel, Hans-Albert; Röser, Hans-Peter

    2010-05-01

    A laser-based rangefinder with high temporal resolution, synchronized with a laser burst, is employed for fast on-site analysis of pulsed free flights. Additional high speed recordings from two different angles of view allow for full 3D-reconstruction of the trajectory and calibration of the rangefinder data. This reveals the whole dynamics of the flyer including the lateral and angular impulse coupling components as well as information on the detonation process. The employment of an ignition pin enhances the reproducibility of the momentum coupling due to a more reliable plasma ignition during the flight. The impact of initial lateral offset is studied and shows beam-riding properties of the parabolic craft within a small range. Back-driving forces are derived and compared with the theoretical model. The flight stability is evaluated with respect to the minimization and compensation of the lateral and angular momentum in a hovering experiment. Stable laser acceleration ranges up to 3 m altitude. Ballistic free flights close to the laboratory ceiling at 7.8 m are reported.

  8. Three-dimensional parabolic equation modeling of mesoscale eddy deflection.

    PubMed

    Heaney, Kevin D; Campbell, Richard L

    2016-02-01

    The impact of mesoscale oceanography, including ocean fronts and eddies, on global scale low-frequency acoustics is examined using a fully three-dimensional parabolic equation model. The narrowband acoustic signal, for frequencies from 2 to 16 Hz, is simulated from a seismic event on the Kerguellen Plateau in the South Indian Ocean to an array of receivers south of Ascension Island in the South Atlantic, a distance of 9100 km. The path was chosen for its relevance to seismic detections from the HA10 Ascension Island station of the International Monitoring System, for its lack of bathymetric interaction, and for the dynamic oceanography encountered as the sound passes the Cape of Good Hope. The acoustic field was propagated through two years (1992 and 1993) of the eddy-permitting ocean state estimation ECCO2 (Estimating the Circulation and Climate of the Ocean, Phase II) system. The range of deflection of the back-azimuth was 1.8° with a root-mean-square of 0.34°. The refraction due to mesoscale oceanography could therefore have significant impacts upon localization of distant low-frequency sources, such as seismic or nuclear test events. PMID:26936572

  9. Thermo-electronic solar power conversion with a parabolic concentrator

    NASA Astrophysics Data System (ADS)

    Olukunle, Olawole C.; De, Dilip K.

    2016-02-01

    We consider the energy dynamics of the power generation from the sun when the solar energy is concentrated on to the emitter of a thermo-electronic converter with the help of a parabolic mirror. We use the modified Richardson-Dushman equation. The emitter cross section is assumed to be exactly equal to the focused area at a height h from the base of the mirror to prevent loss of efficiency. We report the variation of output power with solar insolation, height h, reflectivity of the mirror, and anode temperature, initially assuming that there is no space charge effect. Our methodology allows us to predict the temperature at which the anode must be cooled in order to prevent loss of efficiency of power conversion. Novel ways of tackling the space charge problem have been discussed. The space charge effect is modeled through the introduction of a parameter f (0 < f < 1) in the thermos-electron emission equation. We find that the efficiency of the power conversion depends on solar insolation, height h, apart from radii R of the concentrator aperture and emitter, and the collector material properties. We have also considered solar thermos electronic power conversion by using single atom-layer graphene as an emitter.

  10. Recent Solar Measurements Results at the Parabolic Dish Test Site

    NASA Technical Reports Server (NTRS)

    Ross, D. L.

    1984-01-01

    After the Mexican volcanic eruptions of March 28, April 3 and 4, 1982, the question of its effect on insolation levels at the Parabolic Dish Test Site (PDTS) naturally arose. Clearly, the answer to the original question is that the Mexican volcanic explosion had a significant impact on energy and insolation levels at the PDTS and, furthermore, it has been quite long lasting. The first really significant decrease in energy and insolation levels occurred in June 1982 when the energy level decreased by 19.7% while the peak insolation levels went down by 4.0%. June of 1982 was also the first month (of 13 consecutive months) when peak insolation levels did not equal or exceed 1,000 W/sq m. Signs of a recovery from the effects of the volcanic explosion began to appear in May of 1983, when the energy level exceeded that of May 1981 as well as May 1982. It would appear that energy and insolation levels are improving at the PDTS, but have not quite reached normal or pre-volcanic levels. At this time the data would seem to suggest a return to normal energy and insolation levels will occur in the very near future.

  11. Improved algorithm for solving nonlinear parabolized stability equations

    NASA Astrophysics Data System (ADS)

    Zhao, Lei; Zhang, Cun-bo; Liu, Jian-xin; Luo, Ji-sheng

    2016-08-01

    Due to its high computational efficiency and ability to consider nonparallel and nonlinear effects, nonlinear parabolized stability equations (NPSE) approach has been widely used to study the stability and transition mechanisms. However, it often diverges in hypersonic boundary layers when the amplitude of disturbance reaches a certain level. In this study, an improved algorithm for solving NPSE is developed. In this algorithm, the mean flow distortion is included into the linear operator instead of into the nonlinear forcing terms in NPSE. An under-relaxation factor for computing the nonlinear terms is introduced during the iteration process to guarantee the robustness of the algorithm. Two case studies, the nonlinear development of stationary crossflow vortices and the fundamental resonance of the second mode disturbance in hypersonic boundary layers, are presented to validate the proposed algorithm for NPSE. Results from direct numerical simulation (DNS) are regarded as the baseline for comparison. Good agreement can be found between the proposed algorithm and DNS, which indicates the great potential of the proposed method on studying the crossflow and streamwise instability in hypersonic boundary layers. Project supported by the National Natural Science Foundation of China (Grant Nos. 11332007 and 11402167).

  12. Efficient solution of parabolic equations by Krylov approximation methods

    NASA Technical Reports Server (NTRS)

    Gallopoulos, E.; Saad, Y.

    1990-01-01

    Numerical techniques for solving parabolic equations by the method of lines is addressed. The main motivation for the proposed approach is the possibility of exploiting a high degree of parallelism in a simple manner. The basic idea of the method is to approximate the action of the evolution operator on a given state vector by means of a projection process onto a Krylov subspace. Thus, the resulting approximation consists of applying an evolution operator of a very small dimension to a known vector which is, in turn, computed accurately by exploiting well-known rational approximations to the exponential. Because the rational approximation is only applied to a small matrix, the only operations required with the original large matrix are matrix-by-vector multiplications, and as a result the algorithm can easily be parallelized and vectorized. Some relevant approximation and stability issues are discussed. We present some numerical experiments with the method and compare its performance with a few explicit and implicit algorithms.

  13. Piracetam and fish orientation during parabolic aircraft flight

    NASA Technical Reports Server (NTRS)

    Hoffman, R. B.; Salinas, G. A.; Homick, J. L.

    1980-01-01

    Goldfish were flown in parabolic Keplerian trajectories in a KC-135 aircraft to assay both the effectiveness of piracetam as an antimotion sickness drug and the effectiveness of state-dependent training during periods of oscillating gravity levels. Single-frame analyses of infrared films were performed for two classes of responses - role rates in hypogravity or hypogravity orienting responses (LGR) and climbing responses in hypergravity or hypergravity orienting responses (HGR). In Experiment I, preflight training with the vestibular stressor facilitated suppression of LGR by the 10th parabola. An inverse correlation was found between the magnitudes of LGR and HGR. Piracetam was not effective in a state-dependent design, but the drug did significantly increase HGR when injected into trained fish shortly before flight. In Experiment II, injections of saline, piracetam, and modifiers of gamma-aminobutyric acid - aminooxyacetic acid (AOAA) and isonicotinic acid did not modify LGR. AOAA did significantly increase HGR. Thus, the preflight training has a beneficial effect in reducing disorientation in the fish in weightlessness, but the drugs employed were ineffective.

  14. Evaluation of aerosolized medications during parabolic flight maneuvers

    NASA Technical Reports Server (NTRS)

    Lloyd, Charles W.; Martin, William J.; Gosbee, John

    1991-01-01

    The goal was to visually evaluate the effect gravity has on delivery of medications by the use of various aerosol devices. During parabolic flight the same four aerosols were retested as performed in studio ground tests. It appears that the Cetacaine spray and the Ventolin inhaler function without failure during all test. The pump spray (Nostril) appeared to function normally when the container was full, however it appeared to begin to fail to deliver a full mist with larger droplet size when the container was nearly empty. The simple hand spray bottle appeared to work when the container was full and performed progressively worse as the container was emptied. During Apollo flights, it was reported that standard spray bottles did not work well, however, they did not indicate why. It appears that we would also conclude that standard spray bottles do not function as well in zero gravity by failing to produce a normal mist spray. The standard spray bottle allowed the fluid to come out in a narrow fluid stream when held with the nozzle either level or slightly tilted upward.

  15. Perception of Egocentric Distance during Gravitational Changes in Parabolic Flight.

    PubMed

    Clément, Gilles; Loureiro, Nuno; Sousa, Duarte; Zandvliet, Andre

    2016-01-01

    We explored the effect of gravity on the perceived representation of the absolute distance of objects to the observers within the range from 1.5-6 m. Experiments were performed on board the CNES Airbus Zero-G during parabolic flights eliciting repeated exposures to short periods of microgravity (0 g), hypergravity (1.8 g), and normal gravity (1 g). Two methods for obtaining estimates of perceived egocentric distance were used: verbal reports and visually directed motion toward a memorized visual target. For the latter method, because normal walking is not possible in 0 g, blindfolded subjects translated toward the visual target by pulling on a rope with their arms. The results showed that distance estimates using both verbal reports and blind pulling were significantly different between normal gravity, microgravity, and hypergravity. Compared to the 1 g measurements, the estimates of perceived distance using blind pulling were shorter for all distances in 1.8 g, whereas in 0 g they were longer for distances up to 4 m and shorter for distances beyond. These findings suggest that gravity plays a role in both the sensorimotor system and the perceptual/cognitive system for estimating egocentric distance. PMID:27463106

  16. Parabolic heavy ion flow in the polar magnetosphere

    NASA Technical Reports Server (NTRS)

    Horwitz, J. L.

    1987-01-01

    Recent observations by the Dynamics Explorer 1 satellite over the dayside polar cap magnetosphere have indicated downward flows of heavy ions such as O(+), O(2+), N(+), and N(2+) with flow velocities of the order 1 km/s (Lockwood et al., 1985). These downward flows were interpreted as the result of 'parabolic' flow of these heavy ionospheric ions from a source region associated with the polar cleft topside ionosphere. Here, a two-dimensional kinetic model is utilized to elicit features of the transport of very low energy O(+) ions from the cleft ionosphere. Bulk parameter (density, flux, thermal energies, etc.) distributions in the noon-midnight meridian plane illustrate the effects of varying convection electric fields and source energies. The results illustrate that, particularly under conditions of weak convection electric fields and weak ion heating in the cleft region, much of the intermediate altitude polar cap magnetosphere may be populated by downward flowing heavy ions. It is further shown how two-dimensional transport effects may alter the characteristic vertical profiles of densities and fluxes from ordinary profiles computed in one-dimensional steady-state models.

  17. Perception of Egocentric Distance during Gravitational Changes in Parabolic Flight

    PubMed Central

    Clément, Gilles; Loureiro, Nuno; Sousa, Duarte; Zandvliet, Andre

    2016-01-01

    We explored the effect of gravity on the perceived representation of the absolute distance of objects to the observers within the range from 1.5–6 m. Experiments were performed on board the CNES Airbus Zero-G during parabolic flights eliciting repeated exposures to short periods of microgravity (0 g), hypergravity (1.8 g), and normal gravity (1 g). Two methods for obtaining estimates of perceived egocentric distance were used: verbal reports and visually directed motion toward a memorized visual target. For the latter method, because normal walking is not possible in 0 g, blindfolded subjects translated toward the visual target by pulling on a rope with their arms. The results showed that distance estimates using both verbal reports and blind pulling were significantly different between normal gravity, microgravity, and hypergravity. Compared to the 1 g measurements, the estimates of perceived distance using blind pulling were shorter for all distances in 1.8 g, whereas in 0 g they were longer for distances up to 4 m and shorter for distances beyond. These findings suggest that gravity plays a role in both the sensorimotor system and the perceptual/cognitive system for estimating egocentric distance. PMID:27463106

  18. Numerical Modeling of Year-Round Performance of a Solar Parabolic Dish Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Muthu, G.; Shanmugam, S.; Veerappan, AR.

    2015-08-01

    This paper presents the year-round performance of a solar parabolic dish thermoelectric generator under different values of operating parameters such as ambient temperature, wind velocity, direct normal irradiation, and water inlet temperature to the heat sink. The solar thermoelectric generator (TEG) is examined for an Indian location of Tiruchirappalli. The electrical power output and TEG efficiency are maximum during the months of April and August, while they are minimum during the month of December. It is found that the monthly average hot-side temperature of the TEG varies from 556.53 K to 592.68 K and the cold-side temperature of the TEG varies from 413.21 K to 438.91 K. When the hot-side temperature reaches the optimum value, the conversion efficiency is reduced, although the power increases. A TEG model is useful to find the temperature of the junctions for different operating parameter values and predict the performance of the TEG at any time. A small standalone power-generating system using this technology is a promising option.

  19. Comparison of Fresnel lenses and parabolic mirrors as solar energy concentrators.

    PubMed

    Lorenzo, E; Luque, A

    1982-05-15

    This paper compares the gain that can be achieved with a one- or two-stage concentrator, when the first stage is a Fresnel lens or a parabolic mirror, as a function of the luminosity of the concentrator. The results show that the achievable gain using a parabolic mirror is greater than that obtained using a flat or roof lens but is lower than that obtained using a curved lens. PMID:20389950

  20. Iterative Methods for Solving Nonlinear Parabolic Problem in Pension Saving Management

    NASA Astrophysics Data System (ADS)

    Koleva, M. N.

    2011-11-01

    In this work we consider a nonlinear parabolic equation, obtained from Riccati like transformation of the Hamilton-Jacobi-Bellman equation, arising in pension saving management. We discuss two numerical iterative methods for solving the model problem—fully implicit Picard method and mixed Picard-Newton method, which preserves the parabolic characteristics of the differential problem. Numerical experiments for comparison the accuracy and effectiveness of the algorithms are discussed. Finally, observations are given.

  1. Combined optical solitons with parabolic law nonlinearity and spatio-temporal dispersion

    NASA Astrophysics Data System (ADS)

    Zhou, Qin; Zhu, Qiuping

    2015-03-01

    In this work, combined optical solitons are constructed in a weakly nonlocal nonlinear medium. The spatio-temporal dispersion (STD), parabolic law nonlinearity, detuning, nonlinear dispersion as well as inter-modal dispersion are taken into account. The integration tool that is applied is the complex envelope function ansatz. The influences of different parameters on dynamical behavior of combined optical solitons are discussed. The results are useful in describing the propagation of combined optical solitons with STD and parabolic law nonlinearity.

  2. A parabolic function to modify Thornthwaite estimates of potential evapotranspiration for the eastern United States

    USGS Publications Warehouse

    McCabe, G.J., Jr.

    1989-01-01

    Errors of the Thornthwaite model can be analyzed using adjusted pan evaporation as an index of potential evapotranspiration. An examination of ratios of adjusted pan evaporation to Thornthwaite potential evapotranspiration indicates that the ratios are highest in the winter and lowest during summer months. This trend suggests a parabolic pattern. In this study a parabolic function is used to adjust Thornthwaite estimates of potential evapotranspiration. Forty locations east of the Rocky Mountains are analyzed. -from Author

  3. Stability in terms of two measures for a class of semilinear impulsive parabolic equations

    SciTech Connect

    Dvirnyj, Aleksandr I; Slyn'ko, Vitalij I

    2013-04-30

    The problem of stability in terms of two measures is considered for semilinear impulsive parabolic equations. A new version of the comparison method is proposed, and sufficient conditions for stability in terms of two measures are obtained on this basis. An example of a hybrid impulsive system formed by a system of ordinary differential equations coupled with a partial differential equation of parabolic type is given. The efficiency of the described approaches is demonstrated. Bibliography: 24 titles.

  4. Explicit Nonlinear Finite Element Geometric Analysis of Parabolic Leaf Springs under Various Loads

    PubMed Central

    Kong, Y. S.; Omar, M. Z.; Chua, L. B.; Abdullah, S.

    2013-01-01

    This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE) method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability. PMID:24298209

  5. On the coupling of hyperbolic and parabolic systems: Analytical and numerical approach

    NASA Technical Reports Server (NTRS)

    Gastaldi, Fabio; Quarteroni, Alfio

    1988-01-01

    The coupling of hyperbolic and parabolic systems is discussed in a domain Omega divided into two distinct subdomains omega(+) and omega(-). The main concern is to find the proper interface conditions to be fulfilled at the surface separating the two domains. Next, they are used in the numerical approximation of the problem. The justification of the interface conditions is based on a singular perturbation analysis, i.e., the hyperbolic system is rendered parabolic by adding a small artifical viscosity. As this goes to zero, the coupled parabolic-parabolic problem degenerates into the original one, yielding some conditions at the interface. These are taken as interface conditions for the hyperbolic-parabolic problem. Actually, two alternative sets of interface conditions are discussed according to whether the regularization procedure is variational or nonvariational. It is shown how these conditions can be used in the frame of a numerical approximation to the given problem. Furthermore, a method of resolution is discussed which alternates the resolution of the hyperbolic problem within omega(-) and of the parabolic one within omega(+). The spectral collocation method is proposed, as an example of space discretization (different methods could be used as well); both explicit and implicit time-advancing schemes are considered. The present study is a preliminary step toward the analysis of the coupling between Euler and Navier-Stokes equations for compressible flows.

  6. Seismicity and active tectonic processes in the ultra-slow spreading Lena Trough, Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Läderach, C.; Schlindwein, V.; Schenke, H.-W.; Jokat, W.

    2011-03-01

    With its remote location in the ice-covered Fram Strait, Lena Trough is a poorly known segment of the global mid-ocean ridge system. It is a prominent member of the ultra-slow spreading mid-ocean ridges but its spreading mechanisms are not well understood. We relocalized teleseismically recorded earthquakes from the past five decades to identify tectonic processes in Lena Trough and the adjacent Spitsbergen Fracture Zone (FZ). During two cruises with RV Polarstern in 2008 and 2009 we deployed seismic arrays on ice floes to record the local seismicity of Lena Trough. We could identify and localize microseismic events which we assume to be present in the entire rift valley. In contrast, our relocalization of teleseismically recorded earthquakes shows an asymmetric epicentre distribution along Lena Trough with earthquakes occurring predominately along the western valley flanks of Lena Trough. In 2009 February/March, several high-magnitude earthquakes peaking in an Mb 6.6 event occurred in an outside-corner setting of the Spitsbergen FZ. This is the strongest earthquake which has ever been recorded in Fram Strait and its location at the outside-corner high of the ultra-slow spreading ridge is exceptional. Comparing the seismicity with the magnetic anomalies and high-resolution multibeam bathymetry, we divide Lena Trough in a symmetrically spreading northern part and an asymmetrically spreading southern part south of the South Lena FZ. We propose that a complex interaction between the former De Geer Megashear zone, which separated Greenland from Svalbard starting at Late Mesozoic/Early Cenozoic times, and the developing rift in the southern Lena Trough resulted an increasing eastward dislocation towards the Spitsbergen FZ between older spreading axes and the recent active spreading axis which we believe to be located west of the bathymetric rift valley flanks in a wide extensional plain.

  7. Structural and tectonic evolution of the eastern Cayman Trough (Caribbean Sea) from seismic reflection data

    SciTech Connect

    Leroy, S.; Mauffret, A.; Pubellier, M.

    1996-02-01

    The eastern Cayman Trough preserves a record of the Late Cretaceous to Paleogene Caribbean history that is largely affected by Neogene strike-slip tectonics of the current plate boundary. We conducted an analysis of seismic data within the eastern Cayman Trough, based upon single and multi-channel seismic reflection profiles collected during the Seacarib II cruise in 1987 and the Casis cruise in 1992. These data show that the basement of the eastern Cayman Trough can be divided into four domains from east to west, with distinct morphologic and sedimentary character and inferred older to younger ages: (1) a province of rifted Mesozoic continental crust exhibiting seven parallel horst blocks striking northeast-southwest; (2) a continent-ocean transition between provinces 1 and 3 that exhibits seamounts, small hills, and sedimentary basins; (3) an Eocene oceanic crust with rough basement but smoother relief than the rifted crust; basement trends are roughly north-south and oblique to the northwest trend in domain 1, and (4) the northern Jamaica slope, which forms an east-west-trending slope, with northward-dipping strata that flank the three deeper water domains of the Cayman Trough. The domains are interpreted to be the product of the Eocene east-west opening of the Cayman Trough as a pull-apart basin in a left-lateral strike-slip setting. Closure of the 1100 km of Eocene and younger oceanic crust of the Cayman Trough places the fault-block province adjacent to the Belize margin of Central America. A Neogene phase of transpression has reactivated structures in the four domains, along with on-land structures described by previous authors in Jamaica. The proximity of the eastern margin of the Cayman Trough to petroliferous, continental rocks in Central America suggests an improved possibility of hydrocarbon potential. Unfortunately, sediment thicknesses of less than 1 km probably are not conducive to hydrocarbon formation.

  8. Parabolic Anderson Model in a Dynamic Random Environment: Random Conductances

    NASA Astrophysics Data System (ADS)

    Erhard, D.; den Hollander, F.; Maillard, G.

    2016-06-01

    The parabolic Anderson model is defined as the partial differential equation ∂ u( x, t)/ ∂ t = κ Δ u( x, t) + ξ( x, t) u( x, t), x ∈ ℤ d , t ≥ 0, where κ ∈ [0, ∞) is the diffusion constant, Δ is the discrete Laplacian, and ξ is a dynamic random environment that drives the equation. The initial condition u( x, 0) = u 0( x), x ∈ ℤ d , is typically taken to be non-negative and bounded. The solution of the parabolic Anderson equation describes the evolution of a field of particles performing independent simple random walks with binary branching: particles jump at rate 2 d κ, split into two at rate ξ ∨ 0, and die at rate (- ξ) ∨ 0. In earlier work we looked at the Lyapunov exponents λ p(κ ) = limlimits _{tto ∞} 1/t log {E} ([u(0,t)]p)^{1/p}, quad p in {N} , qquad λ 0(κ ) = limlimits _{tto ∞} 1/2 log u(0,t). For the former we derived quantitative results on the κ-dependence for four choices of ξ : space-time white noise, independent simple random walks, the exclusion process and the voter model. For the latter we obtained qualitative results under certain space-time mixing conditions on ξ. In the present paper we investigate what happens when κΔ is replaced by Δ𝓚, where 𝓚 = {𝓚( x, y) : x, y ∈ ℤ d , x ˜ y} is a collection of random conductances between neighbouring sites replacing the constant conductances κ in the homogeneous model. We show that the associated annealed Lyapunov exponents λ p (𝓚), p ∈ ℕ, are given by the formula λ p({K} ) = {sup} {λ p(κ ) : κ in {Supp} ({K} )}, where, for a fixed realisation of 𝓚, Supp(𝓚) is the set of values taken by the 𝓚-field. We also show that for the associated quenched Lyapunov exponent λ 0(𝓚) this formula only provides a lower bound, and we conjecture that an upper bound holds when Supp(𝓚) is replaced by its convex hull. Our proof is valid for three classes of reversible ξ, and for all 𝓚

  9. Crustal and upper mantle velocity structure of the Salton Trough, southeast California

    USGS Publications Warehouse

    Parsons, T.; McCarthy, J.

    1996-01-01

    This paper presents data and modelling results from a crustal and upper mantle wide-angle seismic transect across the Salton Trough region in southeast California. The Salton Trough is a unique part of the Basin and Range province where mid-ocean ridge/transform spreading in the Gulf of California has evolved northward into the continent. In 1992, the U.S. Geological Survey (USGS) conducted the final leg of the Pacific to Arizona Crustal Experiment (PACE). Two perpendicular models of the crust and upper mantle were fit to wide-angle reflection and refraction travel times, seismic amplitudes, and Bouguer gravity anomalies. The first profile crossed the Salton Trough from the southwest to the northeast, and the second was a strike line that paralleled the Salton Sea along its western edge. We found thin crust (???21-22 km thick) beneath the axis of the Salton Trough (Imperial Valley) and locally thicker crust (???27 km) beneath the Chocolate Mountains to the northeast. We modelled a slight thinning of the crust further to the northeast beneath the Colorado River (???24 km) and subsequent thickening beneath the metamorphic core complex belt northeast of the Colorado River. There is a deep, apparently young basin (???5-6 km unmetamorphosed sediments) beneath the Imperial Valley and a shallower (???2-3 km) basin beneath the Colorado River. A regional 6.9-km/s layer (between ???15-km depth and the Moho) underlies the Salton Trough as well as the Chocolate Mountains where it pinches out at the Moho. This lower crustal layer is spatially associated with a low-velocity (7.6-7.7 km/s) upper mantle. We found that our crustal model is locally compatible with the previously suggested notion that the crust of the Salton Trough has formed almost entirely from magmatism in the lower crust and sedimentation in the upper crust. However, we observe an apparently magmatically emplaced lower crust to the northeast, outside of the Salton Trough, and propose that this layer in part

  10. Cluster eye camera using microlenses on parabolic surface

    NASA Astrophysics Data System (ADS)

    Shen, Hui-Kai; Su, Guo-Dung J.

    2013-10-01

    There are two main types of imaging systems that exist in nature: the single aperture eye and the compound eye. Usually, cameras and most of artificial imaging systems are similar to the single aperture eye. But compound lenses can be more compact than single lenses. Our design is based on insect compound eyes, which also have a wide field of view (FOV). With the rise of micro-optical techniques, fabricating compound lenses has become easier. The simplest form of a curved microlens array is a parabolic surface. In this paper, we proposed a multi-channel imaging system, which combines the principles of the insect compound eye and the human eye. The optical system enables the reduction of track length of the imaging optics to achieve miniaturization. With the aid of optical engineering software ZEMAX, the multi-channel structure is simulated by a curved microlens array, and we use a Hypergon lens as the main lens to simulate the human eye, which can achieve the purpose of the wide FOV. With this architecture, each microlens of a microlens array transmits a segment of the overall FOV. The partial images that are separately recorded in different channels are stitched together to form the final image of the whole FOV by software processing. A 2.74 mm thin imaging system with 59 channels and 90° FOV is optimized using ZEMAX sequential ray tracing software on a 6.16 mm × 4.62 mm image plane. Finally, we will discuss the simulation results of this system and compare it with the optical cluster eye system and a mobile phone patent.

  11. Macrobenthos of the southern part of St. Anna trough and the adjacent Kara Sea shelf

    NASA Astrophysics Data System (ADS)

    Galkin, S. V.; Vedenin, A. A.; Minin, K. V.; Rogacheva, A. V.; Molodtsova, T. N.; Rajskiy, A. K.; Kucheruk, N. V.

    2015-07-01

    Taxonomic composition and ecological structure of benthic communities of the southern part of St. Anna Trough were investigated during the 54th and 59th cruises of RV Akademik Mstislav Keldysh. Material was collected using Sigsbee trawl at 10 stations arranged in two transects (depth range 57-554 m). It was shown that benthic communities of the western arm of the St. Anna Trough differ considerably from the communities of the eastern arm. The western arm communities develop under the influence of active near-bottom hydrodynamics in conditions of rugged topography and a coarse-grained sediment or hard substrate. The wastern arm of the trough is characterized by the predomination of the soft sediment, smooth topography, and weak currents. In the western arm of the trough the influence of the Barents Sea fauna is traced down to the edge of the internal shelf (about 150 m depth). The community of the eastern arm of the trough situated out from the direct influence of the Barents Sea waters represents a continuation of the Ophiocten sericeum community, typical for external Kara Sea shelf. With increasing depth, Ophiopleura borealis becomes the dominant species of the community. In the greatest explored depths some deep-water High-Arctic species, such as echinoids Pourtalesia jeffreysi, were observed. The major factors determining the distribution of benthic communities in the investigated area are the microrelief pattern, the sediment structure, and near-bottom hydrodynamics.

  12. The structure and subsidence of Rockall Trough from two-ship seismic experiments

    SciTech Connect

    Joppen, M.; White, R.S. )

    1990-11-10

    Coincident multichannel seismic reflection and refraction profiles acquired northwest of Britain during a two-ship seismic experiment in the southern Rockall Trough provide evidence for a thin (6 km) syn-rift crust below Rockall Trough. The variation of seismic velocity with depth is consistent with either oceanic crust similar to that found in other parts of the North Atlantic or with thinned continental crust heavily intruded by syn-rift igneous rocks. The syn-rift crust beneath Rockall Trough is now buried by nearly 5 km of sediments that are intruded by Tertiary volcanics varying in extent from isolated sills to a large sill complex extending 100 km laterally. The basement imaged on seismic profiles exhibits a band of subhorizontal reflectors that extend laterally over distances of up to 40 km which they interpret as sediments intercalated with submarine lava flow generated during the opening of the Trough. Estimates of stretching from crustal thinning and from subsidence indicate that Rockall Trough has undergone extensive rifting ({beta} > 6). Upwelling asthenosphere beneath the thinned lithosphere generated at least 1-3 km thickness of melt as it decompressed. The molten rock rose upward from the mantle until it was in part extruded as lava flows and in part intruded into the crust.

  13. The noon and midnight mid-latitude trough as seen by Ariel 4

    NASA Technical Reports Server (NTRS)

    Tulunay, Y. K.; Grebowsky, J. M.

    1978-01-01

    The electron density data returned by the polar orbiting satellites Ariel 3 and Ariel 4 revealed that the midlatitude trough is one of the distinct large-scale features of the ionosphere at about 550 km. Recent work (e.g., Tulunay and Grebowsky, 1975) on the data included the investigation of the temporal development of the latitudinal position of the midlatitude electron density trough at dawn and dusk during the large magnetic storms of May 1967 and May 1972. Model calculations which assumed that the equatorial convection E-field varies in step with the Kp index reproduced on the average the observed behavior. In the present paper, trough observations made at noon and midnight during the period, 12-21 December 1971 which encompassed a relatively large magnetic storm are discussed. In this context, model calculations have been employed as a guide of average approximations of the actual situation in predicting the plasmapause location. It is also shown that the trough observed on the noon passes is not generally plasmapause-related as the nightside troughs are expected to be.

  14. Crustal structure of the NE Rockall Trough from wide-angle seismic data modeling

    NASA Astrophysics Data System (ADS)

    KlingelhöFer, F.; Edwards, R. A.; Hobbs, R. W.; England, R. W.

    2005-11-01

    Two wide-angle seismic lines located in the northern Rockall Trough were acquired in May 2000. One line (line E) crosses the trough from the continental shelf off Lewis to normal oceanic crust west of Lousy Bank in NW-SE direction. The other line (line D) intersects with line E, crosses the Wyville-Thomson Ridge in a SW-NE direction and ends in the Faeroe-Shetland Basin. Sonobuoy data and expanding spread profiles acquired in the same area have been remodeled. Analysis of the seismic data using travel times and amplitudes reveals an up to 5 km thick sedimentary basin including an up to 1.5 km thick basaltic layer which is present in most of the trough. Further conclusions of this study are that the Rockall Trough is underlain by highly stretched continental crust of ˜13 km thickness. The crust thickens to ˜24 km beneath Lousy Bank, which is interpreted to be of continental nature. Beneath the Hebrides continental shelf a three-layer continental crust of 26 km is modeled. An up to 12 km thick high-velocity layer is observed underneath the ocean-continent boundary and is interpreted as magmatic underplating resulting from excess volcanism during rifting. No evidence for an underplate layer could be distinguished beneath the trough area. Modeling of the structure of the Wyville-Thomson Ridge revealed no existing igneous core of the ridge confirming existing theories, that it is a compressional structure.

  15. Precipitation of authigenic uranium in suboxic continental margin sediments from the Okinawa Trough

    NASA Astrophysics Data System (ADS)

    Yamada, Masatoshi; Wang, Zhong-Liang; Kato, Yoshihisa

    2006-02-01

    Concentrations of U and Th isotopes in Okinawa Trough and East China Sea sediment cores were determined by isotope dilution inductively coupled plasma-mass spectrometry (ID-ICP-MS) to investigate the behavior of redox sensitive uranium in suboxic hemipelagic sediments and determine their significance in oceanic uranium balance. 238U concentrations and 238U/ 232Th activity ratios in the East China Sea sediments showed no remarkable variation with depth. However, 238U and 238U/ 232Th ratios in the Okinawa Trough sediments were low in the surface oxidizing layer but increased where the suboxic condition was encountered. The distribution profiles of 230Th and 232Th concentrations were relatively constant with depth in both the Okinawa Trough and East China Sea sediment cores. These results suggested that there has been post-depositional precipitation of authigenic uranium within the suboxic Okinawa Trough sediment column. The post-depositional precipitation rates of authigenic uranium were estimated to be 47 ± 5 to >62 ± 8 ng cm -2 yr -1; these rates were comparable to those previously reported for several anoxic sediments. A mechanism controlling precipitation of uranium may be the downward diffusion of uranium U(VI), reduction to U(IV) and finally precipitation onto the solid phase. The accumulation rate of uranium for the Okinawa Trough sediments was approximately eight times higher than the world average rate reported for suboxic sediments. This removal of uranium in the oceanic budget increases the importance of the suboxic sediment sink.

  16. Altitude Variation of the Plasmapause Signature in the Main Ionospheric Trough

    NASA Technical Reports Server (NTRS)

    Grebowsky, Joseph M.; Benson, Robert F.; Webb, Phillip A.; Truhlik, Vladimir; Bilitza, Dieter

    2009-01-01

    The projection of the plasmapause magnetic-field lines to low altitudes, where the light-ion chemistry is dominated by O(+), tends to occur near the minimum electron density in the main (midlatitude) electron density trough at night. With increasing attitude in the trough, where H(+) emerges as the dominant iota on the low-latitude boundary, we have found cases where the plasmapause field lines are located on the sharp low-Latitude side of the trough as expected if this topside ionosphere H(+) distribution varies in step with the plasmapause gradient in the distant plasmasphere. These conclusions are based on near-equatorial crossings of the plasmapause (corresponding to the steep gradient in the dominant species H(+) by the Explorer-45 satellite as determined from electric-field measurements by Maynard and Cauffman in the early 1970s and ISIS-2 ionospheric topside-sounder measurements. The former data have now been converted to digital form and made available at http://nssdcftp.gsfc.nasa.gov. The latter provide samples of nearly coincident observations of ionospheric main trough crossings near the same magnetic-field lines of the Explorer 45-determined equatorial plasmapause. The ISIS-2 vertical electron density profiles are used to infer where the F-region transitions from an O(+) to a H(+) dominated plasma through the main trough boundaries.

  17. Fault and fluid interaction in the Bradano Trough, southern Italy

    NASA Astrophysics Data System (ADS)

    Sinisi, Rosa; Vita Petrullo, Angela; Agosta, Fabrizio; Paternoster, Michele; Belviso, Claudia; Grassa, Fausto

    2015-04-01

    We report the preliminary results of a multidisciplinary study directed toward a better understanding of the fault and fluid interaction in the Bradano Trough, the foredeep basin of the southern Apennines fold-and-thrust belt, Italy. The work focuses on fresh tuff deposits located along high-angle faults, which crosscut the foredeep basin infill and the Middle Pleistocene Vulture pyroclastic rocks. Two sites have been studied in detail by mean of integrated field and laboratory analyses. The field survey aimed at deciphering both fault architecture (nature, distribution, and relative timing of formation of the various structural elements) and stratigraphy of the fresh tuff deposits. Laboratory investigation of representative samples of both fresh tuff deposits and mineralized fault-related structural elements (e.g, veins and fluid pipe conduits) targeted their textural, mineralogical and stable isotope compositions. The fresh tuff deposits consist of a few m-thick, either well-layered or massive, carbonates that include fossils and syn-depositional calcite veins. These deposits grew primarily by lateral progradation. Optical microscopy analysis is consistent with seven main fresh tuff lithofacies, which all show the following similarities: (i) cement-supported textures; (ii) presence of peloids, phyto- and bio-clasts, imprints of gastropods, bivalves, and plants; (iii) occurrence of shrinkage pores, micropores, and fenestrae that are either partially or totally filled by secondary calcite. XRPD analysis of representative powders showed that calcite is the sole mineral phase except for quartz and feldspar, which are detected in trace in a few samples. Similarly, the mineralogical composition of the fault-related structural elements also shows minor amounts of quartz. Both nature and origin of the quartz mineral will be investigated in a future work. 13C and 18O signatures of representative fresh tuff powders are consistent with a pronounced different isotope

  18. Thermal Studies at the Middle America Trench Offshore Costa Rica and Nankai Trough, Japan

    NASA Astrophysics Data System (ADS)

    Harris, R. N.; Solomon, E. A.; Spinelli, G. A.; Scientific Team of IODP Drilling Expedition 334

    2011-12-01

    Knowledge of the temperature distribution at convergent margins is important to understanding physical and chemical processes such as fluid flow, diagenesis, and faulting mechanics in the forearc region. Seafloor probe measurements offer an economical method for obtaining transects of heat flow across the forearc and along strike. Because these measurements only prick the seafloor they are sensitive to near seafloor processes such as bottom water temperature variations, deformation, and shallow fluid circulation and, although important in their own right, can obfuscate thermal inferences at depth. Ocean drilling provides access to deeper environments where downhole tools, acoustic measurements, and logging technologies can provide important scientific insight. We review recent heat flow results from the Costa Rica and Nankai convergent margins emphasizing ocean drilling transects where measurements of heat flow are available from seafloor probe and ocean drilling. Heat flow measurements offshore the erosive Costa Rican margin show strong along strike variations that reflect different styles of fluid flow and have important impacts on forearc processes. Along both the Nicoya and CRISP drilling transects, heat flow from seafloor probes and ocean drilling are consistent and indicate hydrothermal circulation prior to and after subduction. Fluid flow advects heat from deeper along the subduction thrust and deposits it near the seafloor cooling and warming these regions, respectively. The accretionary Nankai trough also shows important along strike changes in heat flow related to the age of oceanic crust at the trench. Heat flow and geochemical results are consistent with basement fluid flow at the Muroto transect but are more ambiguous at the NanTroSEIZE transect.

  19. ESA Parabolic Flight, Drop Tower and Centrifuge Opportunities for University Students

    NASA Astrophysics Data System (ADS)

    Callens, Natacha; Ventura-Traveset, Javier; Zornoza Garcia-Andrade, Eduardo; Gomez-Calero, Carlos; van Loon, Jack J. W. A.; Pletser, Vladimir; Kufner, Ewald; Krause, Jutta; Lindner, Robert; Gai, Frederic; Eigenbrod, Christian

    The European Space Agency (ESA) Education Office was established in 1998 with the purpose of motivating young people to study science, engineering and technology subjects and to ensure a qualified workforce for ESA and the European space sector in the future. To this end the ESA Education Office is supporting several hands-on activities including small student satellites and student experiments on sounding rockets, high altitude balloons as well as microgravity and hypergravity platforms. This paper is intended to introduce three new ESA Education Office hands-on activities called "Fly Your Thesis!", "Drop Your Thesis!" and "Spin Your Thesis!". These activities give re-spectively access to aircraft parabolic flight, drop tower and centrifuge campaigns to European students. These educational programmes offer university students the unique opportunity to design, build, and eventually perform, in microgravity or hypergravity, a scientific or techno-logical experiment which is linked to their syllabus. During the "Fly Your Thesis!" campaigns, the students accompany their experiments onboard the A300 Zero-G aircraft, operated by the company Novespace, based in Bordeaux, France, for a series of three flights of 30 parabolas each, with each parabola providing about 20s of microgravity [1]. "Drop Your Thesis!" campaigns are held in the ZARM Drop Tower, in Bremen, Germany. The installation delivers 4.74s of microgravity in dropping mode and 9.3s in the catapulting mode [2]. Research topics such as fluid physics, fundamental physics, combustion, biology, material sciences, heat transfer, astrophysics, chemistry or biochemistry can greatly benefit from using microgravity platforms. "Spin Your Thesis!" campaigns take place in the Large Diameter Centrifuge (LDC) facility, at ESTEC, Noordwijk, in the Netherlands. This facility offers an acceleration from 1 to 20 times Earth's gravity [3]. The use of hypergravity allows completing the scientific picture of how gravity has an

  20. Paleoenvironmental Assessment and Deglacial Chronology of the Onondaga Trough, Onondaga County, New York

    USGS Publications Warehouse

    Kappel, William M.; Teece, Mark A.

    2007-01-01

    Introduction The U.S. Geological Survey, in cooperation with the Onondaga Lake Partnership and Onondaga Environmental Institute, has been studying the hydrogeology of the Onondaga Trough since 2002 to determine the movement and concentration of naturally occurring brine in the glacial valley-fill aquifer. Numerous shallow and deep test holes have been drilled to determine the glacial and water-quality stratigraphy in the Onondaga Trough. Organic materials were recovered from the Onondaga Creek, Ninemile Creek, and Harbor Brook valleys, and from lakebed sediments in Onondaga Lake (fig. 1) and age-dated with carbon-isotope analysis techniques. This report summarizes the carbon-isotope data collected from 1996 through 2006 in the Onondaga Trough. The results of these analyses provide a means to understand the deglaciation of the watershed and the development of the watershed from barren glacial sediment to a forested ecosystem.

  1. Stratigraphic framework and petroleum potential of Northeastern Baltimore Canyon Trough, Mid-Atlantic Outer Continental Shelf

    SciTech Connect

    Libby-French, J.

    1984-01-01

    Geologic data from 29 wells in the Baltimore Canyon Trough were released to the public as of 1982, and provide sufficient information for establishing Upper Jurassic through Cenozoic rock-stratigraphic units. The oldest rocks penetrated by exploratory wells are of Late Jurassic age and are correlative to the Scotian Shelf Mohawk, Mic Mac, and Abenaki Formations. The Mohawk(.) sandstone and Mic Mac shale equivalents in the Baltimore Canyon Trough represent lower delta plain to predominantly prodelta environments, and the Abenaki-equivalent limestone represents a shelfmargin carbonate buildup. A destructional phase of the delta is represented by the Naskapi equivalents a calcareous shale. Stratigraphic traps may be present in the Baltimore Canyon Trough Upper Jurassic and Lower Cretaceous deltaic sandstones and shelf-margin carbonates. The deltaic units contain channel and distributary-mouth-bar sandstones, which may be potential reservoirs. The Abenaki stratigraphic-reef trend provides another potential target.

  2. A vacuum tube vee-trough collector for solar heating and air conditioning applications

    NASA Technical Reports Server (NTRS)

    Selcuk, M. K.

    1978-01-01

    An analysis is conducted of the performance of a vee-trough vacuum tube collector proposed for use in solar heating and cooling applications. The vee-trough reflector is a triangular sectioned, flat surfaced reflector, whose axis is laid in the East-West direction. A vacuum tube receiver placed at the bottom of the vee-trough collects solar heat most efficiently since convection is completely eliminated. Radiation losses are reduced by use of selective coatings on the absorber. Owing to its high temperature capabilities (300-400 F), the proposed scheme could also be used for power generation applications in combination with an organic Rankine conversion system. It is especially recommended for unattended pumping stations since the reflectors only require reversal once every six months.

  3. The origin of polygonal troughs on the northern plains of Mars

    NASA Technical Reports Server (NTRS)

    Pechmann, J. C.

    1980-01-01

    The morphology, distribution, geologic environment and relative age of large-scale polygonal trough systems on Mars are examined. The troughs are steep-walled, flat-floored, sinuous depressions typically 200-800 m wide, 20-120 m deep and spaced 5-10 km apart. The mechanics of formation of tension cracks is reviewed to identify the factors controlling the scale of tension crack systems; special emphasis is placed on thermal cracking in permafrost. It is shown that because of the extremely large scale of the Martian fracture systems, they could not have formed by thermal cracking in permafrost, dessication cracking in sediments or contraction cracking in cooling lava. On the basis of photogeologic evidence and analog studies, it is proposed that polygonal troughs on the northern plains of Mars are grabens.

  4. Crustal deformation at the Nankai Trough estimated from seafloor geodetic observations

    NASA Astrophysics Data System (ADS)

    Watanabe, T.; Tadokoro, K.; Ikuta, R.; Okuda, T.; Nagai, S.; Kuno, M.

    2012-12-01

    The Philippine Sea plate subducts beneath the southwest Japan along the Nankai Trough with a rate of about 4-6 cm/yr, where megathrust earthquakes have repeatedly occurred every 100-150 years. Because the region expected to be the hypocentral area of next Nankai and Tonankai earthquakes is almost located in offshore area, it is important to know the spatio-temporal variation of crustal deformation accompanied with plate interaction in high precision. For this issue, we have conducted seafloor geodetic observation at the Nankai Trough using a GPS/Acoustic technique since 2004. In this system, we estimate the position of a surveying vessel by Kinematic GPS analysis and measure the distance between the vessel and the benchmark on the seafloor by Acoustic measurements. Next we determine the location of the benchmark. For the repeatability of this observation, the location of benchmark is determined within a precision of 2-3 cm at horizontal components. Several seafloor benchmarks are located at the Nankai Trough, which are individually operated by Japan Coast Guard, Tohoku University, and Nagoya University. In the Kumano Basin, we have three seafloor benchmarks located about 60-80 km away from the deformation front of the Nankai Trough. The observations from 2005 to 2011 have illustrated that those benchmarks are moving at rates of about 4 cm/yr toward west-northwest with velocity uncertainties of about 2 cm/yr relative to the Amurian plate. In this study, to explain the crustal deformation derived from seafloor geodetic observations especially at the shallower part of the Nankai Trough, we conduct numerical simulations using finite element method and then discuss the interplate coupling at the Nankai Trough.

  5. Tectonics of the Dalrymple Trough and uplift of the Murray Ridge (NW Indian Ocean)

    NASA Astrophysics Data System (ADS)

    Rodriguez, Mathieu; Chamot-Rooke, Nicolas; Huchon, Philippe; Fournier, Marc; Lallemant, Siegfried; Delescluse, Matthias; Zaragosi, Sébastien; Mouchot, Nicolas

    2014-12-01

    The Dalrymple Trough is a 150-km-long, 30-km-wide basin located at the northern termination of the Owen Fracture Zone (OFZ), which is the present-day active India-Arabia plate boundary. The Dalrymple Trough is closely associated with the Murray Ridge, a complex of prominent bathymetric highs located on its eastern flank. Recent multibeam mapping of the connection between the Dalrymple Trough and the OFZ revealed a horsetail structure, which suggests a close relationship between geological histories of both structures. However, the 3-6 Ma age of initiation of the OFZ contrasts with the commonly accepted Early Miocene emplacement of the Dalrymple Trough. Recent seismic lines document a new tectonic history of the Dalrymple Trough, involving two major episodes of deformation along the India-Arabia plate boundary at ~ 8-10 Ma and ~ 1.9 ± 0.9 Ma. The 8-10 Ma episode is marked by a system of folds linked to the main uplift of the southern Murray Ridge and the first uplift of the northern Murray Ridge. This episode is related to a global plate reorganization event in the Late Miocene, well expressed by intraplate deformation in the Central Indian Ocean. The Dalrymple Trough opened at ~ 1.9 ± 0.9 Ma subsequently to the formation of a stepover at the India-Arabia plate boundary, coeval with the regional M-unconformity in the Oman abyssal plain, which marks a structural reorganization of the Makran accretionary wedge, and the last uplift of the northern Murray Ridge.

  6. New Results and Future IPY Investigations in Hektoria Trough, Inner Larsen-B Embayment, Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Brachfeld, S.; Domack, E. W.; Leventer, A.; Willmott, V.; Ishman, S.

    2007-12-01

    We present new results from a sediment core collected in the inner Larsen-B embayment, Antarctic Peninsula. The 2002 break-up of the Larsen-B Ice Shelf enabled access to the termini of glaciers that formerly fed into the ice shelf. United States Antarctic Program cruise LMG05-02 discovered and mapped an 800-m deep glacial trough off Hektoria Glacier at the northern end of the Larsen-B embayment. Sub-bottom profiling reveals the presence of at least 20-m of unconsolidated sediment in the trough, which varies in character between acoustically laminated, and packages with weak, discontinuous reflectors. A 2.5-m kasten core was recovered from the Hektoria trough during cruise LMG05-02. The sediment consists of silty clay with a minor component of very fine sand, and is laminated in the uppermost meter. Downcore magnetic and geochemical parameters were used to investigate the terrigenous sediment supplied to Hektoria Trough. Bulk sediment geochemistry suggests a constant sediment source that is chemically consistent with upper continental crust. Magnetic parameters reveal several intervals in which the magnetic material supplied to the trough varies in abundance and particle size. We observe shifts at approximately 850, 5900, and 7900 14C yr B.P., based on a preliminary age model. Superimposed on these shifts are periodic pulses of coarser material into the trough, which may be related to fluctuations in the location of the grounding line with respect to the core site. Our preliminary age model indicates an average sedimentation rate of 21 cm/kyr, which suggests that the basin fill extends back to perhaps 100,000 yr B.P., a rare archive of the late Pleistocene in an ice proximal site.

  7. Controls of bioclastic turbidite deposition in eastern Muertos Trough northeast Caribbean Sea

    SciTech Connect

    Forsthoff, G.M.; Holcombe, T.L.

    1985-02-01

    A study of seismic-reflection profiles and sediment cores establishes regional bathymetric and source area control over the composition, transport, and distribution of turbidites in the eastern Muertos Trough, Bioclastic (carbonate) turbidites dominate the eastern portion of the trough. Analyses of carbon content and sand-sized components suggest that the bioclastic turbidites (characterized by planktonic foraminifera, pteropods, and sponge spicules) are reworked pelagic oozes originally deposited on the outer-shelf and upper-slope areas south of St. Croix and eastern Puerto Rico. The presence of several intrashelf and upper-slope basins prohibits shallow-water carbonate sediments from entering the Muertos Trough. Volcanic rock fragments derived from Puerto Rico are transported to the trough via the Guayanilla Canyon system. Mixing of the volcanic fragments with outer-shelf and upper-slope lutites results in mixed bioclastic-terrigenous turbidites south of central and western Puerto Rico. The paucity of shallow-water carbonate sediments in the trough suggests that the submarine canyons are effective conduits for the rapid transport of volcaniclastic sands across the shelf and thereby prevent extensive mixing with inner- and middle-shelf carbonate sediments. Sediment transport within the trough is primarily axial in an east-west direction. Outer trench-wall fault scarps, south of Guayanilla Canyon, limit the southerly progradation of the trench-wedge facies and deflect incoming gravity flows in a down-axis (westward) direction. Where no faults exist, the trench wedge progrades southward and interfingers with the pelagic sediments of the northern Venezuelan basin.

  8. Interband magneto-spectroscopy in InSb square and parabolic quantum wells

    SciTech Connect

    Kasturiarachchi, T.; Edirisooriya, M.; Mishima, T. D.; Doezema, R. E.; Santos, M. B.; Saha, D.; Pan, X.; Sanders, G. D.; Stanton, C. J.

    2015-06-07

    We measure the magneto-optical absorption due to intersubband optical transitions between conduction and valence subband Landau levels in InSb square and parabolic quantum wells. InSb has the narrowest band gap (0.24 eV at low temperature) of the III–V semiconductors leading to a small effective mass (0.014 m{sub 0}) and a large g–factor (−51). As a result, the Landau level spacing is large at relatively small magnetic fields (<8 T), and one can observe spin-splitting of the Landau levels. We examine two structures: (i) a multiple-square-well structure and (ii) a structure containing multiple parabolic wells. The energies and intensities of the strongest features are well explained by a modified Pidgeon-Brown model based on an 8-band k•p model that explicitly incorporates pseudomorphic strain. The strain is essential for obtaining agreement between theory and experiment. While modeling the square well is relatively straight-forward, the parabolic well consists of 43 different layers of various thickness to approximate a parabolic potential. Agreement between theory and experiment for the parabolic well validates the applicability of the model to complicated structures, which demonstrates the robustness of our model and confirms its relevance for developing electronic and spintronic devices that seek to exploit the properties of the InSb band structure.

  9. Curvilinear parabolic approximation for surface wave transformation with wave current interaction

    NASA Astrophysics Data System (ADS)

    Shi, Fengyan; Kirby, James T.

    2005-04-01

    The direct coordinate transformation method, which only transforms independent variables and retains Cartesian dependent variables, may not be an appropriate method for the purpose of simplifying the curvilinear parabolic approximation of the vector form of the wave-current equation given by Kirby [Higher-order approximations in the parabolic equation method for water waves, J. Geophys. Res. 91 (1986) 933-952]. In this paper, the covariant-contravariant tensor method is used for the curvilinear parabolic approximation. We use the covariant components of the wave number vector and contravariant components of the current velocity vector so that the derivation of the curvilinear equation closely follows the higher-order approximation in rectangular Cartesian coordinates in Kirby [Higher-order approximations in the parabolic equation method for water waves, J. Geophys. Res. 91 (1986) 933-952]. The resulting curvilinear equation can be easily implemented using the existing model structure and numerical schemes adopted in the Cartesian parabolic wave model [J.T. Kirby, R.A. Dalrymple, F. Shi, Combined Refraction/Diffraction Model REF/DIF 1, Version 2.6. Documentation and User's Manual, Research Report, Center for Applied Coastal Research, Department of Civil and Environmental Engineering, University of Delaware, Newark, 2004]. Several examples of wave simulations in curvilinear coordinate systems, including a case with wave-current interaction, are shown with comparisons to theoretical solutions or measurement data.

  10. Stratigraphic framework of Cambrian and Ordovician rocks across Rome Trough, central Appalachian basin

    SciTech Connect

    Ryder, R.T.

    1987-09-01

    Restored stratigraphic cross sections drawn primarily through the subsurface of parts of Pennsylvania, Ohio, West Virginia, Kentucky, and Tennessee provide new detailed information to further the understanding of Cambrian and Ordovician sedimentation and tectonics associated with the Rome trough sector of the Appalachian basin. Drilled thickness of the Cambrian and Ordovician sequence ranges from a maximum of about 14,500 ft (4.5 km) along the axis of the trough to a minimum of about 3500 ft (1 km) on the western flank.

  11. Carbon isotope systematics of individual hydrocarbons in hydrothermal petroleum from Escanaba Trough, Northeastern Pacific Ocean

    USGS Publications Warehouse

    Simoneit, B.R.T.; Schoell, M.; Kvenvolden, K.A.

    1997-01-01

    We submitted individual aliphatic and polycyclic aromatic hydrocarbons in samples of hydrothermal petroleum from Escanaba trough to compound specific isotope analysis to trace their origins. The carbon isotope compositions of the alkanes and polycyclic aromatic hydrocarbons (means -27.5 and -24.7%, respectively) reflect a primarily terrestrial organic matter source.We submitted individual aliphatic and polycyclic aromatic hydrocarbons in samples of hydrothermal petroleum from Escanaba Trough to compound specific isotope analysis to trace their origins. The carbon isotope compositions of the alkanes and polycyclic aromatic hydrocarbons (means -27.5 and -24.7 per mill, respectively) reflect a primarily terrestrial organic matter source.

  12. New Insights into the Spiral Troughs of the Northern Polar Layered Deposits, Mars from SHARAD Observations

    NASA Astrophysics Data System (ADS)

    Smith, I.; Holt, J. W.; Phillips, R. J.

    2009-12-01

    The SHAllow RADar (SHARAD) instrument on Mars Reconnaissance Orbiter greatly expands our ability to study the Polar Layered Deposits (PLDs) by resolving internal layers and structure with a theoretical vertical resolution in ice of ~ 8 m and horizontal resolution of 0.3-1 km (along track) x 3-6 km (cross track). This complements high-resolution optical imagery, which has been used for decades as the basis for studying surface features and developing hypotheses linking them to known processes. Spiral trough and scarp migration in the northern PLD (NPLD) has been a topic of debate since the idea was first proposed (Howard, Icarus 34/3, pp. 581-599, 1978). Layers observed on the equator-facing slopes of the troughs are generally truncated at the surface, while no layers are generally seen on the pole-facing slopes. Scenarios involving wind erosion, solar ablation, and atmospheric deposition in relative amounts have been hypothesized to explain this stratigraphy. Other studies indicate that the troughs have not migrated, instead being recently eroded into the NPLD. The advent of high-resolution radar sounding provides the first opportunity to address this debate through the analysis of subsurface stratigraphy. SHARAD data reveal stratigraphic discontinuities indicating that most troughs initiated ~ 500 m below the present surface, persisted throughout subsequent deposition, and have indeed migrated (Smith et al., LPSC 40, Abstract 1423, 2009). We have conducted additional analyses at various NPLD localities showing that the migration takes multiple stratigraphic forms, some of which do not include discontinuities. The longest troughs of the NPLD, in the 0-90°E quadrant north of Gemini Lingula, have stratigraphy with layer thickness variations that correlate well to those predicted by wind-driven migration. Troughs nearer the NPLD margin at ~90°E show a different structure corresponding more to insolation-dominated ablation. Between these locations and at other places

  13. Environmental Controls and Eco-geomorphic Interactions of the Barchan-to-parabolic Dune Stabilisation and the Parabolic-to-barchan Dune Reactivation

    NASA Astrophysics Data System (ADS)

    Yan, Na; Baas, Andreas

    2015-04-01

    Parabolic dunes are one of a few common aeolian landforms which are highly controlled by eco-geomorphic interactions. Parabolic dunes, on the one hand, can be developed from highly mobile dune landforms, barchans for instance, in an ameliorated vegetation condition; or on the other hand, they can be reactivated and transformed back into mobile dunes due to vegetation deterioration. The fundamental mechanisms and eco-geomorphic interactions controlling both dune transformations remain poorly understood. To bridge the gap between complex processes involved in dune transformations on a relatively long temporal scale and real world monitoring records on a very limited temporal scale, this research has extended the DECAL model to incorporate 'dynamic' growth functions and the different 'growth' of perennial shrubs between growing and non-growing seasons, informed by field measurements and remote sensing analysis, to explore environmental controls and eco-geomorphic interactions of both types of dune transformation. A non-dimensional 'dune stabilising index' is proposed to capture the interactions between environmental controls (i.e. the capabilities of vegetation to withstand wind erosion and sand burial, the sandy substratum thickness, the height of the initial dune, and the sand transport potential), and establish the linkage between these controls and the geometry of a stabilising dune. An example demonstrates how to use the power-law relationship between the dune stabilising index and the normalised migration distance to assist in extrapolating the historical trajectories of transforming dunes. The modelling results also show that a slight increase in vegetation cover of an initial parabolic dune can significantly increase the reactivation threshold of climatic impact (both drought stress and wind strength) required to reactivate a stabilising parabolic dune into a barchan. Four eco-geomorphic interaction zones that govern a barchan-to-parabolic dune transformation

  14. Environmental risks of the gas hydrate field development in the Eastern Nankai Trough

    NASA Astrophysics Data System (ADS)

    Yamamoto, K.; Nagakubo, S.

    2009-12-01

    To establish any kinds of new energy resources, environmental impacts of the technology should be well understood before full industrial implementation. Methane hydrate (MH), a relatively clean fossil energy with low CO2 and no SOx emission, is not an exception. Because methane gas itself has strong greenhouse gas effect, and methane hydrate is not stable under the atmospheric pressure and room temperature, public image of MH field development is very risky game and potentially disastrous to the global climate. However, the real physics of the MH bearing sediments is far different from such images. MH21 Research Consortium in Japan has studied about the resource assessment and production techniques to develop MH since 2001. As the results, we found several gas hydrate concentrated zones with pore filling type hydrate in sandy layers of turbidite sediment in the Eastern Nankai Trough area off coasts of the Central Japan. The depressurization technique, in the other word, in-situ MH dissociation by water production and natural heat supply from surrounding formation, will be used as the basic method to produce methane gas from MH. Under the conditions, we have evaluated realistic environmental risk of the MH production. Because the most MH found in the Eastern Nankai Trough are composed of biogenic and almost pure methane, there is no concern of sea water contamination by oil releases that is the most common environmental disaster caused by misconducts of the oil industry. Also MH reservoirs there are not pressurized, and blowout of wells during drilling is very unlikely. Endothermic MH dissociation process decreases formation temperature with depressurization, and give negative feedback, then, there is no chance of chain reaction. Heat supply from surrounding formations is necessary for continuous dissociation, but heat transfer in the formations is relatively slow, and the dissociation rate is limited. Once the operation to pump water in boreholes for

  15. Technology.

    ERIC Educational Resources Information Center

    Online-Offline, 1998

    1998-01-01

    Focuses on technology, on advances in such areas as aeronautics, electronics, physics, the space sciences, as well as computers and the attendant progress in medicine, robotics, and artificial intelligence. Describes educational resources for elementary and middle school students, including Web sites, CD-ROMs and software, videotapes, books,…

  16. Porous media matric potential and water content measurements during parabolic flight.

    PubMed

    Norikane, Joey H; Jones, Scott B; Steinberg, Susan L; Levine, Howard G; Or, Dani

    2005-01-01

    Control of water and air in the root zone of plants remains a challenge in the microgravity environment of space. Due to limited flight opportunities, research aimed at resolving microgravity porous media fluid dynamics must often be conducted on Earth. The NASA KC-135 reduced gravity flight program offers an opportunity for Earth-based researchers to study physical processes in a variable gravity environment. The objectives of this study were to obtain measurements of water content and matric potential during the parabolic profile flown by the KC-135 aircraft. The flight profile provided 20-25 s of microgravity at the top of the parabola, while pulling 1.8 g at the bottom. The soil moisture sensors (Temperature and Moisture Acquisition System: Orbital Technologies, Madison, WI) used a heat-pulse method to indirectly estimate water content from heat dissipation. Tensiometers were constructed using a stainless steel porous cup with a pressure transducer and were used to measure the matric potential of the medium. The two types of sensors were placed at different depths in a substrate compartment filled with 1-2 mm Turface (calcined clay). The ability of the heat-pulse sensors to monitor overall changes in water content in the substrate compartment decreased with water content. Differences in measured water content data recorded at 0, 1, and 1.8 g were not significant. Tensiometer readings tracked pressure differences due to the hydrostatic force changes with variable gravity. The readings may have been affected by changes in cabin air pressure that occurred during each parabola. Tensiometer porous membrane conductivity (function of pore size) and fluid volume both influence response time. Porous media sample height and water content influence time-to-equilibrium, where shorter samples and higher water content achieve faster equilibrium. Further testing is needed to develop these sensors for space flight applications. PMID:15751144

  17. Porous media matric potential and water content measurements during parabolic flight

    NASA Technical Reports Server (NTRS)

    Norikane, Joey H.; Jones, Scott B.; Steinberg, Susan L.; Levine, Howard G.; Or, Dani

    2005-01-01

    Control of water and air in the root zone of plants remains a challenge in the microgravity environment of space. Due to limited flight opportunities, research aimed at resolving microgravity porous media fluid dynamics must often be conducted on Earth. The NASA KC-135 reduced gravity flight program offers an opportunity for Earth-based researchers to study physical processes in a variable gravity environment. The objectives of this study were to obtain measurements of water content and matric potential during the parabolic profile flown by the KC-135 aircraft. The flight profile provided 20-25 s of microgravity at the top of the parabola, while pulling 1.8 g at the bottom. The soil moisture sensors (Temperature and Moisture Acquisition System: Orbital Technologies, Madison, WI) used a heat-pulse method to indirectly estimate water content from heat dissipation. Tensiometers were constructed using a stainless steel porous cup with a pressure transducer and were used to measure the matric potential of the medium. The two types of sensors were placed at different depths in a substrate compartment filled with 1-2 mm Turface (calcined clay). The ability of the heat-pulse sensors to monitor overall changes in water content in the substrate compartment decreased with water content. Differences in measured water content data recorded at 0, 1, and 1.8 g were not significant. Tensiometer readings tracked pressure differences due to the hydrostatic force changes with variable gravity. The readings may have been affected by changes in cabin air pressure that occurred during each parabola. Tensiometer porous membrane conductivity (function of pore size) and fluid volume both influence response time. Porous media sample height and water content influence time-to-equilibrium, where shorter samples and higher water content achieve faster equilibrium. Further testing is needed to develop these sensors for space flight applications.

  18. Survival of the causative agent of Johne’s disease (Mycobacterium avium subsp paratuberculosis) in biofilms on trough materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Livestock watering troughs are frequented by all animals on a farm, they provide a moist, nutrient rich environment for bacterial survival and the trough basin provides a surface for bacterial adhesion (i.e., biofilm formation). MAP has been shown to have a very hydrophic cell wall structure (as do ...

  19. 9 CFR 82.21 - Vehicles, cages, coops, containers, troughs, and other equipment used for infected poultry.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., troughs, and other equipment used for infected poultry. 82.21 Section 82.21 Animals and Animal Products... ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS NEWCASTLE DISEASE AND CHLAMYDIOSIS Chlamydiosis in Poultry § 82.21 Vehicles, cages, coops, containers, troughs, and other equipment used for infected poultry....

  20. 9 CFR 82.21 - Vehicles, cages, coops, containers, troughs, and other equipment used for infected poultry.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., troughs, and other equipment used for infected poultry. 82.21 Section 82.21 Animals and Animal Products... ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS EXOTIC NEWCASTLE DISEASE (END) AND CHLAMYDI-OSIS Chlamydiosis in Poultry § 82.21 Vehicles, cages, coops, containers, troughs, and other equipment used...

  1. 9 CFR 82.21 - Vehicles, cages, coops, containers, troughs, and other equipment used for infected poultry.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., troughs, and other equipment used for infected poultry. 82.21 Section 82.21 Animals and Animal Products... ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS EXOTIC NEWCASTLE DIS- EASE (END) AND CHLAMYDIOSIS Chlamydiosis in Poultry § 82.21 Vehicles, cages, coops, containers, troughs, and other equipment used...

  2. 9 CFR 82.21 - Vehicles, cages, coops, containers, troughs, and other equipment used for infected poultry.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., troughs, and other equipment used for infected poultry. 82.21 Section 82.21 Animals and Animal Products... ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS EXOTIC NEWCASTLE DISEASE (END) AND CHLAMYDI-OSIS Chlamydiosis in Poultry § 82.21 Vehicles, cages, coops, containers, troughs, and other equipment used...

  3. 9 CFR 82.21 - Vehicles, cages, coops, containers, troughs, and other equipment used for infected poultry.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., troughs, and other equipment used for infected poultry. 82.21 Section 82.21 Animals and Animal Products... ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS EXOTIC NEWCASTLE DIS- EASE (END) AND CHLAMYDIOSIS Chlamydiosis in Poultry § 82.21 Vehicles, cages, coops, containers, troughs, and other equipment used...

  4. Transition from self tilt to object tilt during maintained lateral tilt in parabolic flight

    NASA Astrophysics Data System (ADS)

    Wetzig, Joachim; Reiser, Michaela; von Baumgarten, Rudolf J.

    19 young healthy subjects were subjected to parabolic rollercoaster flight. A horizontal luminous line was seen by the subjects in a headfixed goggle device. During the hypergravic phases of parabolic flight the luminous line seemed to rotate into and during the hypogravic phase against the direction of static head tilt. Ocular counter rotation and activity of the neck position receptors cannot explain these subjective rotations. We conclude that information from the otolith system, converging with visual information within the brain, dislocated the headfixed visual target line. While the retinal image of the luminous line remains unchanged, loading and unloading the otoliths in parabolic flight changes the sensation of self tilt into object tilt, hereby subjectively rotating visual targets such as the luminous line.

  5. Two parabolic equations for propagation in layered poro-elastic media.

    PubMed

    Metzler, Adam M; Siegmann, William L; Collins, Michael D; Collis, Jon M

    2013-07-01

    Parabolic equation methods for fluid and elastic media are extended to layered poro-elastic media, including some shallow-water sediments. A previous parabolic equation solution for one model of range-independent poro-elastic media [Collins et al., J. Acoust. Soc. Am. 98, 1645-1656 (1995)] does not produce accurate solutions for environments with multiple poro-elastic layers. First, a dependent-variable formulation for parabolic equations used with elastic media is generalized to layered poro-elastic media. An improvement in accuracy is obtained using a second dependent-variable formulation that conserves dependent variables across interfaces between horizontally stratified layers. Furthermore, this formulation expresses conditions at interfaces using no depth derivatives higher than first order. This feature should aid in treating range dependence because convenient matching across interfaces is possible with discretized derivatives of first order in contrast to second order. PMID:23862802

  6. Parabolic equation solution of seismo-acoustics problems involving variations in bathymetry and sediment thickness.

    PubMed

    Collis, Jon M; Siegmann, William L; Jensen, Finn B; Zampolli, Mario; Küsel, Elizabeth T; Collins, Michael D

    2008-01-01

    Recent improvements in the parabolic equation method are combined to extend this approach to a larger class of seismo-acoustics problems. The variable rotated parabolic equation [J. Acoust. Soc. Am. 120, 3534-3538 (2006)] handles a sloping fluid-solid interface at the ocean bottom. The single-scattering solution [J. Acoust. Soc. Am. 121, 808-813 (2007)] handles range dependence within elastic sediment layers. When these methods are implemented together, the parabolic equation method can be applied to problems involving variations in bathymetry and the thickness of sediment layers. The accuracy of the approach is demonstrated by comparing with finite-element solutions. The approach is applied to a complex scenario in a realistic environment. PMID:18177137

  7. Existence of eigenvalues of problem with shift for an equation of parabolic-hyperbolic type

    NASA Astrophysics Data System (ADS)

    Tengayeva, Aizhan; Dildabek, Gulnar

    2016-08-01

    In the present paper, a spectral problem for an operator of parabolic-hyperbolic type of I kind with non-classical boundary conditions is considered. The problem is considered in a standard domain. The parabolic part of the space is a rectangle. And the hyperbolic part of the space coincides with a characteristic triangle. We consider a problem with the local boundary condition in the domain of parabolicity and with the boundary condition with displacement in the domain of hyperbolicity. We prove the strong solvability of the considered problem. The main aim of the paper is the research of spectral properties of the problem. The existence of eigenvalues of the problem is proved.

  8. Tailored dispersion profile in controlling optical solitons in a tapered parabolic index fiber

    NASA Astrophysics Data System (ADS)

    Prakash, S. Arun; Malathi, V.; Mani Rajan, M. S.

    2016-03-01

    We investigate the soliton dynamics in tapered parabolic index fibers via symbolic computation for a variety of dispersion profiles to inspect how a specific dispersion profile controls the optical soliton. By means of AKNS procedure, Lax pair is constructed for nonlinear Schrödinger equation with variable coefficients. Using obtained Lax pair, multi-soliton solutions are generated via Darboux transformation technique. Using multi-soliton solutions, soliton dynamics in tapered parabolic index fiber with the hyperbolic, Gaussian, exponential, and linear profiles are discussed. Results obtained in this study will be of certain potential application on construction of the nonlinear optical devices by soliton control. Results obtained in this study will be of certain value to the studies on the propagation and application of the soliton in the tapered parabolic index fiber and dispersion-managed fiber system.

  9. A method for the spatial discretization of parabolic equations in one space variable

    SciTech Connect

    Skeel, R.D.; Berzins, M.

    1987-02-01

    The aim of this paper is to describe and analyze a new spatial discretization method for parabolic equations in one space variable: Ordinary and parabolic partial differential equations in one space variable x often have a singularity due to the use of polar cylindrical or spherical coordinates. The method we propose is a simple piecewise nonlinear Galerkin/Petrov-Galerkin method which is second order accurate in space. (It supersedes the method proposed by Skeel). The case m = 1 involves the use of the logarithm function, which is probably the only accurate way to model the logarithmic singularity present in the solution. A code based on a variant of the proposed method has already been included as part of the SPRINT package of Berzins, Dew, and Furzeland. The method that we propose here will be distributed in the next release of the D03P (parabolic equations) section of the NAG Library. 18 refs.

  10. A parabolic analogue of the higher-order comparison theorem of De Silva and Savin

    NASA Astrophysics Data System (ADS)

    Banerjee, Agnid; Garofalo, Nicola

    2016-01-01

    We show that the quotient of two caloric functions which vanish on a portion of the lateral boundary of a H k + α domain is H k + α up to the boundary for k ≥ 2. In the case k = 1, we show that the quotient is in H 1 + α if the domain is assumed to be space-time C 1, α regular. This can be thought of as a parabolic analogue of a recent important result in [8], and we closely follow the ideas in that paper. We also give counterexamples to the fact that analogous results are not true at points on the parabolic boundary which are not on the lateral boundary, i.e., points which are at the corner and base of the parabolic boundary.

  11. UPC BarcelonaTech Platform. Innovative aerobatic parabolic flights for life sciences experiments.

    NASA Astrophysics Data System (ADS)

    Perez-Poch, Antoni; Gonzalez, Daniel

    We present an innovative method of performing parabolic flights with aerobatic single-engine planes. A parabolic platform has been established in Sabadell Airport (Barcelona, Spain) to provide an infraestructure ready to allow Life Sciences reduced gravity experiments to be conducted in parabolic flights. Test flights have demonstrated that up to 8 seconds of reduced gravity can be achieved by using a two-seat CAP10B aircraft, with a gravity range between 0.1 and 0.01g in the three axis. A parabolic flight campaign may be implemented with a significant reduction in budget compared to conventional parabolic flight campaigns, and with a very short time-to-access to the platform. Operational skills and proficiency of the pilot controling the aircraft during the maneuvre, sensitivity to wind gusts, and aircraft balance are the key issues that make a parabola successful. Efforts are focused on improving the total “zero-g” time and the quality of reduced gravity achieved, as well as providing more space for experiments. We report results of test flights that have been conducted in order to optimize the quality and total microgravity time. A computer sofware has been developed and implemented to help the pilot optimize his or her performance. Finally, we summarize the life science experiments that have been conducted in this platform. Specific focus is given to the very successful 'Barcelona ZeroG Challenge', this year in its third edition. This educational contest gives undergraduate and graduate students worldwide the opportunity to design their research within our platform and test it on flight, thus becoming real researchers. We conclude that aerobatic parabolic flights have proven to be a safe, unexpensive and reliable way to conduct life sciences reduced gravity experiments.

  12. Parabolic replicator dynamics and the principle of minimum Tsallis information gain

    PubMed Central

    2013-01-01

    Background Non-linear, parabolic (sub-exponential) and hyperbolic (super-exponential) models of prebiological evolution of molecular replicators have been proposed and extensively studied. The parabolic models appear to be the most realistic approximations of real-life replicator systems due primarily to product inhibition. Unlike the more traditional exponential models, the distribution of individual frequencies in an evolving parabolic population is not described by the Maximum Entropy (MaxEnt) Principle in its traditional form, whereby the distribution with the maximum Shannon entropy is chosen among all the distributions that are possible under the given constraints. We sought to identify a more general form of the MaxEnt principle that would be applicable to parabolic growth. Results We consider a model of a population that reproduces according to the parabolic growth law and show that the frequencies of individuals in the population minimize the Tsallis relative entropy (non-additive information gain) at each time moment. Next, we consider a model of a parabolically growing population that maintains a constant total size and provide an “implicit” solution for this system. We show that in this case, the frequencies of the individuals in the population also minimize the Tsallis information gain at each moment of the ‘internal time” of the population. Conclusions The results of this analysis show that the general MaxEnt principle is the underlying law for the evolution of a broad class of replicator systems including not only exponential but also parabolic and hyperbolic systems. The choice of the appropriate entropy (information) function depends on the growth dynamics of a particular class of systems. The Tsallis entropy is non-additive for independent subsystems, i.e. the information on the subsystems is insufficient to describe the system as a whole. In the context of prebiotic evolution, this “non-reductionist” nature of parabolic replicator

  13. Numerical solution of the stochastic parabolic equation with the dependent operator coefficient

    SciTech Connect

    Ashyralyev, Allaberen; Okur, Ulker

    2015-09-18

    In the present paper, a single step implicit difference scheme for the numerical solution of the stochastic parabolic equation with the dependent operator coefficient is presented. Theorem on convergence estimates for the solution of this difference scheme is established. In applications, this abstract result permits us to obtain the convergence estimates for the solution of difference schemes for the numerical solution of initial boundary value problems for parabolic equations. The theoretical statements for the solution of this difference scheme are supported by the results of numerical experiments.

  14. Generation and tooth contact analysis of spiral bevel gears with predesigned parabolic functions of transmission errors

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Lee, Hong-Tao

    1989-01-01

    A new approach for determination of machine-tool settings for spiral bevel gears is proposed. The proposed settings provide a predesigned parabolic function of transmission errors and the desired location and orientation of the bearing contact. The predesigned parabolic function of transmission errors is able to absorb piece-wise linear functions of transmission errors that are caused by the gear misalignment and reduce gear noise. The gears are face-milled by head cutters with conical surfaces or surfaces of revolution. A computer program for simulation of meshing, bearing contact and determination of transmission errors for misaligned gear has been developed.

  15. Transesophageal echocardiographic evaluation of baboons during microgravity induced by parabolic flight

    NASA Technical Reports Server (NTRS)

    Vernalis, Marina N.; Latham, Ricky D.; Fanton, John W.; Geffney, F. Andrew

    1993-01-01

    Transthoracic echocardiography (TTE) is a feasible method to noninvasively examine cardiac anatomy during parabolic flight. However, transducer placement on the chest wall is very difficult to maintain during transition to microgravity. In addition, TTE requires the use of low frequency transponders which limit resolution. Transesophical echocardiography (TEE) is an established imaging technique which obtains echocardiographic information from the esophagus. It is a safe procedure and provides higher quality images of cardiac structure than obtained with TTE. This study is designed to determine whether TEE was feasible to perform during parabolic flight and to determine whether acute central volume responses occur in acute transition to zero gravity by direct visualization of the cardiac chambers.

  16. Two-electron states and state exchange time control in parabolic quantum dot

    NASA Astrophysics Data System (ADS)

    Baghdasaryan, D. A.; Kazaryan, E. M.; Sarkisyan, H. A.

    2014-04-01

    Using the Heisenberg uncertainty relationship and the stationary perturbation theory we consider two-electron states in a spherically symmetric parabolic quantum dot (parabolic helium atom). The dependence of ground-state energy on the QD size is studied. The energy of two-electron system monotonically decreases with QD radius increase. The problem of the state exchange time control in QD is discussed, taking into account the spins of the electrons in the Russell-Saunders approximation. With the increase of the QD radius the state exchange time increases.

  17. The poleward edge of the mid-latitude trough - Its formation, orientation and dynamics

    NASA Astrophysics Data System (ADS)

    Rodger, A. S.; Brace, L. H.; Hoegy, W. R.; Winningham, J. D.

    1986-08-01

    Data from the Advanced Ionospheric Sounder (AIS) deployed at Halley, Antarctica (76-deg S, 27-deg W; L = 4.2) and the Dynamics Explorer-2 spacecraft (DE-2) are used to investigate several aspects of the formation processes and dynamics of the poleward edge of the midlatitude electron density trough. These include a study of the flux and energy of charged particles precipitating into the F-region as a function of Magnetic Local Time. It is found that local energetic electron precipitation is a major source of ionization of the poleward edge in the evening sector, but only after magnetic midnight transport processes become more important. Occasionally a significant increase in the flux of conjugate photoelectrons is colocated with the poleward edge of the trough in the morning sector. The combination of AIS and DE-2 data has allowed identification of significant longitudinal structure on the poleward edge of the trough that may be the result of substorm activity. It is found that the orientation of the poleward edge of the trough and the locus of the plasmapause predicted from the 'tear-drop' model vary in rather a similar manner with local time, though no close physical link between the two features is inferred from this coincidence.

  18. The poleward edge of the mid-latitude trough - Its formation, orientation and dynamics

    NASA Technical Reports Server (NTRS)

    Rodger, A. S.; Brace, L. H.; Hoegy, W. R.; Winningham, J. D.

    1986-01-01

    Data from the Advanced Ionospheric Sounder (AIS) deployed at Halley, Antarctica (76-deg S, 27-deg W; L = 4.2) and the Dynamics Explorer-2 spacecraft (DE-2) are used to investigate several aspects of the formation processes and dynamics of the poleward edge of the midlatitude electron density trough. These include a study of the flux and energy of charged particles precipitating into the F-region as a function of Magnetic Local Time. It is found that local energetic electron precipitation is a major source of ionization of the poleward edge in the evening sector, but only after magnetic midnight transport processes become more important. Occasionally a significant increase in the flux of conjugate photoelectrons is colocated with the poleward edge of the trough in the morning sector. The combination of AIS and DE-2 data has allowed identification of significant longitudinal structure on the poleward edge of the trough that may be the result of substorm activity. It is found that the orientation of the poleward edge of the trough and the locus of the plasmapause predicted from the 'tear-drop' model vary in rather a similar manner with local time, though no close physical link between the two features is inferred from this coincidence.

  19. Electromagnetic emissions and fine structures observed near main ionospheric trough during geomagnetic storms and their interactions

    NASA Astrophysics Data System (ADS)

    Przepiórka, Dorota; Marek, Michał; Matyjasiak, Barbara; Rothkaehl, Hanna

    2016-04-01

    Geomagnetic conditions triggered by the solar activity affect the ionosphere, its fine and global structures. Very intense magnetic storms substantially change the plasma density, concentration and circulation. Especially sensitive region is located near auroral oval, where most energy is deposited during geomagnetic storms. In this region and just below it, where the main ionospheric trough is located, we observe enhanced electromagnetic emissions in different frequency ranges. In particular the AKR-like (Auroral Kilometric Radiation) emissions are seen at frequencies of the order of hundreds of kHz in the ionosphere, just below the auroral oval. Analyzing spectrograms from DEMETER mission and comparing them with electron density measurements from DEMETER, we found that AKR-like emissions are seen near poleward wall of the main ionospheric trough, during geomagnetic storms. Main ionospheric trough is known as a turbulent region which properties change as the geomagnetic storm evolves. This work is an attempt to determine how the presence of the different emissions affect main ionospheric trough parameters such as location, width and depth. Data used in this study come from DEMETER and RELEC missions. This work was partly supported by NCN grant Rezonans 2012/07/B/ST9/04414.

  20. Vertical tectonics in northern Escanaba Trough as recorded by thick late Quaternary turbidites

    USGS Publications Warehouse

    Normark, W.R.; Serra, F.

    2001-01-01

    Escanaba Trough, the southernmost segment of the Gorda Ridge, is filled by as much as 500 m of late Quaternary turbidite and hemipelagic sediment. Coring at Deep Sea Drilling Project Site 35 and Ocean Drilling Program (ODP) Sites 1037 and 1038 together with 4.5-kHz deep-tow and 3.5-kHz surface-ship seismic reflection profiles enable a distinct pattern of reflections to be mapped throughout Escanaba Trough in the upper part of this sediment fill. The uppermost 80 m of turbidite sediment, which includes at least 11 turbidity current events, were deposited in 3200 m. The turbidity currents were trapped upon entering Escanaba Trough, resulting in all of the sediment in suspension in the flows being deposited. The thickness of the turbidite layers reflects both the flow thickness and the vertical grain concentration within the flow that deposited the layer. Variations in the turbidite thickness with respect to water depth can be used to estimate the degree of relative vertical movement within the floor of Escanaba Trough. In the area of hydrothermal activity near ODP Site 1038, uplift of as much as 140 m has occurred over the past 8 kyr. Copyright 2001 by the American Geophysical Union.

  1. Drilling investigations of crustal rifting processes in the Salton Trough, California. Revision 1

    SciTech Connect

    Kasameyer, P.W.; Younker, L.W.; Newmark, R.L.; Duba, A.G.

    1986-01-01

    The results of CSDP activities in the Salton Sea Geothermal Field (SSGF) are briefly described, concentrating on a shallow heat flow survey, but also discussing preliminary results from the Salton Sea Scientific Drilling Program (SSSDP). The hypothesis that localized thermal zones are the source of all the heat in the Salton Trough is examined. (ACR)

  2. Effect of Watering Trough Chlorination on Persistence of Mycobacterium avium subsp. Paratuberculosi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The continued global increase in the number of cases of Johne’s disease suggests that more information is needed to understand the mechanisms by which the causative agent Mycobacterium avium subsp. paratuberculosis (MAP) is spread among livestock on the farm site. Livestock watering troughs are freq...

  3. Drilling investigations of crustal rifting processes in the Salton Trough, California

    SciTech Connect

    Kasameyer, P.W.; Younker, L.W.; Newmark, R.L.; Duba, A.G.

    1986-01-01

    The paper describes the results of CSDP activities in the Salton Sea Geothermal Field (SSGF), concentrating on a shallow heat-flow survey, but also considering preliminary results from the Salton Sea Scientific Drilling Program (SSSDP). Whether the heat input rate to localized systems is high enough to account for the overall thermal budget of the Salton Trough is examined. (ACR)

  4. Molecular Cytogenetics in Trough Shells (Mactridae, Bivalvia): Divergent GC-Rich Heterochromatin Content.

    PubMed

    García-Souto, Daniel; Pérez-García, Concepción; Kendall, Jack; Pasantes, Juan J

    2016-01-01

    The family Mactridae is composed of a diverse group of marine organisms, commonly known as trough shells or surf clams, which illustrate a global distribution. Although this family includes some of the most fished and cultured bivalve species, their chromosomes are poorly studied. In this work, we analyzed the chromosomes of Spisula solida, Spisula subtruncata and Mactra stultorum by means of fluorochrome staining, C-banding and fluorescent in situ hybridization using 28S ribosomal DNA (rDNA), 5S rDNA, H3 histone gene and telomeric probes. All three trough shells presented 2n = 38 chromosomes but different karyotype compositions. As happens in most bivalves, GC-rich regions were limited to the nucleolus organizing regions in Spisula solida. In contrast, many GC-rich heterochromatic bands were detected in both Spisula subtruncata and Mactra stultorum. Although the three trough shells presented single 5S rDNA and H3 histone gene clusters, their chromosomal locations differed. Regarding major rDNA clusters, while Spisula subtruncata presented a single cluster, both Spisula solida and Mactra stultorum showed two. No evidence of intercalary telomeric signals was detected in these species. The molecular cytogenetic characterization of these taxa will contribute to understanding the role played by chromosome changes in the evolution of trough shells. PMID:27537915

  5. Vertical structure, physical properties, and energy exchange of the East Asian trough in boreal winter

    NASA Astrophysics Data System (ADS)

    Leung, Marco Yu-Ting; Zhou, Wen

    2015-09-01

    The relation between the intensity of the East Asian trough and the strength of the East Asian winter monsoon is documented. A prominent dipole of the available potential energy of the zonal mean flow can be observed over the midlatitudes and polar regions and is related to temperature anomalies. Variation in the intensity of the East Asian trough is caused by variation in the energy conversion from the available potential energy of the zonal mean flow to the East Asian trough. The in-phase relation between the intensities of the East Asian jet and East Asian trough is illustrated by the relation between the potential energy and kinetic energy of stationary eddies. The dipole of height anomalies over the midlatitude and polar regions develops in late autumn and decays in early spring. We investigate the effect of both stationary and transient eddy forcing on the evolution of the dipole. The combined forcing of the two types of eddy makes an important contribution to the development, maintenance, and decay of the dipole.

  6. Superplumes and ridge interactions between Ontong Java and Manihiki Plateaus and the Nova-Canton Trough

    NASA Astrophysics Data System (ADS)

    Larson, Roger L.

    1997-09-01

    The initial pulse of volcanism on the Ontong Java and Manihiki Plateaus began prior to 123 124 Ma and had largely ceased by about 122 Ma, whereas the intervening Pacific-Phoenix spreading ridge probably was disrupted between 120 and 115 Ma by formation of the Nova-Canton Trough rift system. Plateau formation may have resulted from a large plume head that rose beneath each of the two plateau sites. During the plateau eruption phase, these two plumes spread beyond the plateaus and within the asthenosphere. They eventually coalesced beneath the intervening spreading ridge, where the Nova-Canton Trough rift system is now located, at about the time volcanism ceased on the plateaus. The two plumes combined to form the Nova-Canton Trough rift system by reheating the nascent lithosphere near the ridge crest and widening the plate boundary from the usual 1 10 km to a much broader region. The present rift system is a maximum of 500 km wide, and much of this area may have formed by normal faulting and crustal accretion across the broadened plate boundary as plate divergence continued. Eventually, coherent spreading resumed somewhere south of the Nova-Canton Trough rift system.

  7. Molecular Cytogenetics in Trough Shells (Mactridae, Bivalvia): Divergent GC-Rich Heterochromatin Content

    PubMed Central

    García-Souto, Daniel; Pérez-García, Concepción; Kendall, Jack; Pasantes, Juan J.

    2016-01-01

    The family Mactridae is composed of a diverse group of marine organisms, commonly known as trough shells or surf clams, which illustrate a global distribution. Although this family includes some of the most fished and cultured bivalve species, their chromosomes are poorly studied. In this work, we analyzed the chromosomes of Spisula solida, Spisula subtruncata and Mactra stultorum by means of fluorochrome staining, C-banding and fluorescent in situ hybridization using 28S ribosomal DNA (rDNA), 5S rDNA, H3 histone gene and telomeric probes. All three trough shells presented 2n = 38 chromosomes but different karyotype compositions. As happens in most bivalves, GC-rich regions were limited to the nucleolus organizing regions in Spisula solida. In contrast, many GC-rich heterochromatic bands were detected in both Spisula subtruncata and Mactra stultorum. Although the three trough shells presented single 5S rDNA and H3 histone gene clusters, their chromosomal locations differed. Regarding major rDNA clusters, while Spisula subtruncata presented a single cluster, both Spisula solida and Mactra stultorum showed two. No evidence of intercalary telomeric signals was detected in these species. The molecular cytogenetic characterization of these taxa will contribute to understanding the role played by chromosome changes in the evolution of trough shells. PMID:27537915

  8. Carbon isotope systematics of individual hydrocarbons in hydrothermal petroleum from Escanaba Trough, northeastern Pacific Ocean.

    PubMed

    Simoneit, B R; Schoell, M; Kvenvolden, K A

    1997-01-01

    We submitted individual aliphatic and polycyclic aromatic hydrocarbons in samples of hydrothermal petroleum from Escanaba Trough to compound specific isotope analysis to trace their origins. The carbon isotope compositions of the alkanes and polycyclic aromatic hydrocarbons (means -27.5 and -24.7%, respectively) reflect a primarily terrestrial organic matter source. PMID:11541391

  9. The measurement of cold ion densities in the plasma trough. [in magnetosphere

    NASA Technical Reports Server (NTRS)

    Harris, K. K.

    1974-01-01

    The cold ion density in the plasma trough region is an important fundamental parameter in the currently proposed mechanisms to describe magnetospheric dynamics. Direct in situ measurements of the cold ion density are generally difficult owing to uncertainties in vehicle potentials and ion temperatures. It is shown that the light ion mass spectrometer from Ogo 5 was very successful in acquiring these data and that vehicle potentials appear not to have been a prohibitive factor. The cold ion plasma trough data show a great deal of variability, indicating a strong dependence on the state of the convection electric field; consequently, average values of cold ion densities in the plasma trough may be significantly different from the actual time-dependent values. The local time plot of plasma trough densities at L = 7 for data acquired over a 1-year period shows the anticipated increase in cold ion density during the daytime and the expected decrease in cold ion density during dusk and early nighttime.

  10. Lena Trough (Arctic Ocean): Active mantle exhumation on a continental rifted margin

    NASA Astrophysics Data System (ADS)

    Snow, J. E.; Hellebrand, E.; von der Handt, A.; Nauret, F.

    2004-12-01

    Lena Trough is the northern continuation of the Mid-Atlantic Ridge through Fram Strait and into the Arctic Ocean. The rifting of Lena Trough began in the Miocene, and significantly, is the final and the most recent event in the separation of the North American from the Eurasian continent. Lena Trough was mapped in 1999, 2001 and 2004 by PFS Polarstern (Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany), revealing sea floor structures that are inconsistent with any normally conceived mid-ocean ridge spreading, and instead indicative of late continental rifting. Lena Trough is shown to be a deep, fault-bounded basin with depths of 3800-4200m, and irregular, steep valley sides that are oblique to the spreading direction. Basement horst structures that outcrop as sigmoidal ridges with steeply dipping sides project out of the valley floor. These basement ridges are roughly parallel along flow lines to the valley walls on either side. Ridge-orthogonal topography is simply absent (ie no segments trending parallel nor fracture zones perpendicular to Gakkel Ridge). Most faults trend approximately SSE-NNW, an obliquity with respect to Gakkel Ridge (SW-NE) of about 55°. The basement ridges are composed nearly entirely of fertile mantle peridotite, as are the valley walls. Only at the northern and southern extremities of Lena Trough do basalts appear at all. The peridotites compositions are consistent with either continental or oceanic (asthenospheric) mantle. They show evidence of low-degree mantle melting, followed by high-level stagnation in a thick lithosphere. This evidence (veining, impregnation) is more evident where little or no basaltic cover is present, while peridotites dredged in the vicinity of basalts tend to be more residual. This may indicate some degree of magmatic focusing in the absence of a basaltic crust per se. Lena Trough contains rare, highly alkaline basalts that are unlike any compositions dredged from mid-ocean ridges

  11. Lena Trough (Arctic Ocean): Active mantle exhumation on a continental rifted margin

    NASA Astrophysics Data System (ADS)

    Snow, J. E.; Hellebrand, E.; von der Handt, A.; Nauret, F.

    2007-12-01

    Lena Trough is the northern continuation of the Mid-Atlantic Ridge through Fram Strait and into the Arctic Ocean. The rifting of Lena Trough began in the Miocene, and significantly, is the final and the most recent event in the separation of the North American from the Eurasian continent. Lena Trough was mapped in 1999, 2001 and 2004 by PFS Polarstern (Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany), revealing sea floor structures that are inconsistent with any normally conceived mid-ocean ridge spreading, and instead indicative of late continental rifting. Lena Trough is shown to be a deep, fault-bounded basin with depths of 3800-4200m, and irregular, steep valley sides that are oblique to the spreading direction. Basement horst structures that outcrop as sigmoidal ridges with steeply dipping sides project out of the valley floor. These basement ridges are roughly parallel along flow lines to the valley walls on either side. Ridge-orthogonal topography is simply absent (ie no segments trending parallel nor fracture zones perpendicular to Gakkel Ridge). Most faults trend approximately SSE-NNW, an obliquity with respect to Gakkel Ridge (SW-NE) of about 55°. The basement ridges are composed nearly entirely of fertile mantle peridotite, as are the valley walls. Only at the northern and southern extremities of Lena Trough do basalts appear at all. The peridotites compositions are consistent with either continental or oceanic (asthenospheric) mantle. They show evidence of low-degree mantle melting, followed by high-level stagnation in a thick lithosphere. This evidence (veining, impregnation) is more evident where little or no basaltic cover is present, while peridotites dredged in the vicinity of basalts tend to be more residual. This may indicate some degree of magmatic focusing in the absence of a basaltic crust per se. Lena Trough contains rare, highly alkaline basalts that are unlike any compositions dredged from mid-ocean ridges

  12. Rare gases in lavas from the ultraslow spreading Lena Trough, Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Nauret, F.; Moreira, M.; Snow, J. E.

    2010-06-01

    Mid-ocean ridge basalts (MORB) from the Arctic Ocean have been much less studied than those from the Indian, Atlantic, and Pacific due to the difficulty of access related to ice cover. In 2001 and 2004 the Arctic ridges (Gakkel Ridge and Lena Trough) were intensively sampled. In this study we present the first helium, neon, and argon concentrations and isotopic ratios in a suite of samples from the ultraslow spreading Lena Trough (˜0.75 cm/yr effective full rate). Central Lena Trough (CLT) lavas display 4He/3He between 89,710 and 97,530 (R/Ra between 7.4 and 8.1), similar to the mean MORB ratio of 90,000 ± 10,000 (R/Ra = 8 ± 1). In a three neon isotope diagram, the samples fall on the MORB line, without showing any excess of nucleogenic 21Ne. The 40Ar/36Ar ratios vary from 349 to 6964. CLT samples have a typical MORB He and Ne isotopic composition. Rare gases do not indicate any mantle heterogeneities or contribution of subcontinental lithospheric mantle, although this has been suggested previously on the basis of the Sr-Nd and Pb isotopic systems. Based on noble gas systematics, a DUPAL-like anomaly is not observed in the Arctic Ocean. We propose two possible models which reconcile the rare gases with these previous studies. The first is that the Lena Trough mantle has a marble cake structure with small-scale heterogeneities (<1 km), allowing rapid diffusion and homogenization of rare gases compared to elements such as Sr, Nd, and Pb. The second model proposes that the recycled component identified by other isotopic systems was fully degassed at a recent date. It would therefore have a negligible mass budget of rare gases compared to other isotopic systems. This would suggest that the mantle enrichment beneath Lena Trough was generated by rift-forming processes and not by recycling.

  13. Gas potential of the Rome Trough in Kentucky: Results of recent Cambrian exploration

    SciTech Connect

    Harris, D.C.; Drahovzal, J.A.

    1996-09-01

    A recent gas discovery in the Rome Trough suggests the need to re-evaluate the deep Cambrian potential of eastern Kentucky. A new phase of Cambrian exploration began in mid-1994 with a new pool discovery by the Carson Associates No. 1 Kazee well in Elliott County, Ky. This well blew out and initially flowed 11 MMcfd of gas from the upper Conasauga Group/Rome Formation at 6,258 to 6,270 feet. After this discovery, a second exploratory well (the Blue Ridge No. 1Greene) was drilled on a separate structure in Elliott County in late 1995. The Blue Ridge well was temporarily abandoned, but had shows of gas and condensate. In early 1996, Carson Associates offset their initial discovery well with the No. 33 Lawson Heirs well. This activity follows a frustrating exploration history in the Rome Trough that is marked by numerous gas and oil shows, but rare commercial production. Only three single-well pools have produced commercial gas from the trough, including the recent Kazee well. Stratigraphic units below the Cambrian-Ordovician Knox Group in the Rome Trough are dramatically thicker than their equivalents on the shelf to the north. The interval in the trough is thought to include rocks as old as Early Cambrian, consisting of a basal sandstone, equivalents of the Shady/Tomstown Dolomite, the Rome Formation, and the Conasauga Formation. Sandstones and fractured shales have been responsible for most of the production to date, but dolostone intervals may also have potential. Limited seismic data indicate possible fan-delta and basin-floor fan deposits that may have reservoir potential.

  14. Optical analysis of a photovoltaic V-trough system installed in western India.

    PubMed

    Maiti, Subarna; Sarmah, Nabin; Bapat, Pratap; Mallick, Tapas K

    2012-12-20

    The low concentrating photovoltaic (PV) system such as a 2× V-trough system can be a promising choice for enhancing the power output from conventional PV panels with the inclusion of thermal management. This system is more attractive when the reflectors are retrofitted to the stationary PV panels installed in a high aspect ratio in the north-south direction and are tracked 12 times a year manually according to preset angles, thus eliminating the need of diurnal expensive tracking. In the present analysis, a V-trough system facing exactly the south direction is considered, where the tilt angle of the PV panels' row is kept constant at 18.34°. The system is installed on the terrace of CSIR-Central Salt and Marine Chemicals Research Institute in Bhavnagar, Gujarat, India (21.47 N, 71.15 E). The dimension of the entire PV system is 9.64 m×0.55 m. The V-troughs made of anodized aluminum reflectors (70% specular reflectivity) had the same dimensions. An in-house developed; experimentally validated Monte Carlo ray-trace model was used to study the effect of the angular variation of the reflectors throughout a year for the present assembly. Results of the ray trace for the optimized angles showed the maximum simulated optical efficiency to be 85.9%. The spatial distribution of solar intensity over the 0.55 m dimension of the PV panel due to the V-trough reflectors was also studied for the optimized days in periods that included solstices and equinoxes. The measured solar intensity profiles with and without the V-trough system were used to calculate the actual optical efficiencies for several sunny days in the year, and results were validated with the simulated efficiencies within an average error limit of 10%. PMID:23262601

  15. Parabolic flight experience is related to increased release of stress hormones.

    PubMed

    Schneider, Stefan; Brümmer, Vera; Göbel, Simon; Carnahan, Heather; Dubrowski, Adam; Strüder, Heiko K

    2007-06-01

    Numerous studies have shown significant effects of weightlessness on adaptational processes of the CNS, cardiovascular and/or muscular system. Most of these studies have been carried out during parabolic flights, using the recurring 20 s of weightlessness at each parabola. Although some of these studies reported on potential influences not only of weightlessness but also of the stressful situation within a parabolic flight, especially provoked by the ongoing changes between 1.8, 1 and 0 G, so far there seems to be only marginal information about objective parameters of stress evoked by parabolic flights. By collecting blood samples from a permanent venous catheter several times during parabolic flights, we were able to show an increase of prolactin, cortisol and ACTH in the course of a 120 min flight. We conclude, therefore, that previous reported effects of weightlessness on adaptational processes may be affected not only by weightlessness but also by the exposure to other stressors experienced within the environment of a Zero-G airbus. PMID:17351784

  16. Quasilinear parabolic variational inequalities with multi-valued lower-order terms

    NASA Astrophysics Data System (ADS)

    Carl, Siegfried; Le, Vy K.

    2014-10-01

    In this paper, we provide an analytical frame work for the following multi-valued parabolic variational inequality in a cylindrical domain : Find and an such that where is some closed and convex subset, A is a time-dependent quasilinear elliptic operator, and the multi-valued function is assumed to be upper semicontinuous only, so that Clarke's generalized gradient is included as a special case. Thus, parabolic variational-hemivariational inequalities are special cases of the problem considered here. The extension of parabolic variational-hemivariational inequalities to the general class of multi-valued problems considered in this paper is not only of disciplinary interest, but is motivated by the need in applications. The main goals are as follows. First, we provide an existence theory for the above-stated problem under coercivity assumptions. Second, in the noncoercive case, we establish an appropriate sub-supersolution method that allows us to get existence, comparison, and enclosure results. Third, the order structure of the solution set enclosed by sub-supersolutions is revealed. In particular, it is shown that the solution set within the sector of sub-supersolutions is a directed set. As an application, a multi-valued parabolic obstacle problem is treated.

  17. Estimation of discontinuous coefficients in parabolic systems: Applications to reservoir simulation

    NASA Technical Reports Server (NTRS)

    Lamm, P. D.

    1984-01-01

    Spline based techniques for estimating spatially varying parameters that appear in parabolic distributed systems (typical of those found in reservoir simulation problems) are presented. The problem of determining discontinuous coefficients, estimating both the functional shape and points of discontinuity for such parameters is discussed. Convergence results and a summary of numerical performance of the resulting algorithms are given.

  18. Simple Verification of the Parabolic Shape of a Rotating Liquid and a Boat on Its Surface

    ERIC Educational Resources Information Center

    Sabatka, Z.; Dvorak, L.

    2010-01-01

    This article describes a simple and inexpensive way to create and to verify the parabolic surface of a rotating liquid. The liquid is water. The second part of the article deals with the problem of a boat on the surface of a rotating liquid. (Contains 1 table, 10 figures and 5 footnotes.)

  19. Stability of shock waves for multi-dimensional hyperbolic-parabolic conservation laws

    NASA Astrophysics Data System (ADS)

    Li, Dening

    1988-01-01

    The uniform linear stability of shock waves is considerd for quasilinear hyperbolic-parabolic coupled conservation laws in multi-dimensional space. As an example, the stability condition and its dynamic meaning for isothermal shock wave in radiative hydrodynamics are analyzed.

  20. Ex Vivo Assessment of a Parabolic-Tip Inflow Cannula for Pediatric Continuous-Flow VADs.

    PubMed

    Griffin, Michael T; Grzywinski, Matthew F; Voorhees, Hannah J; Kameneva, Marina V; Olia, Salim E

    2016-01-01

    To address the challenge of unloading the left ventricle during pediatric mechanical circulatory support using next-generation rotary blood pumps, a novel inflow cannula was developed. This unique inflow cannula for pediatric, continuous-flow, left ventricular assist devices (VADs) with a parabolic-shaped inlet entrance was evaluated alongside a bevel-tip and fenestrated-tip cannula via an ex vivo, isolated-heart experimental setup. Performance was characterized using two clinical scenarios of over-pumping and hypovolemia, created by varying pump speed and filling preload pressure, respectively, at ideal and off-axis cannula placement to assess ventricular unloading and positional sensitivity. Quantitative and qualitative assessments were performed on the resultant hemodynamics and intra-ventricular boroscopic images to classify conditions of nonsuction, partial, gradual or severe entrainment, and ventricular collapse. The parabolic-tip cannula was found to be significantly less sensitive to placement position (p < 0.001) than the bevel-tip cannula under all conditions, while not statistically different from the fenestrated cannula. Visual analysis of the parabolic-tip cannula showed complete resistance to entrainment, whereas the fenestrated-tip had partial entrainment in 90% and 87% of the over-pumping and hypovolemic studies, respectively. We conclude that future pediatric VAD designs may benefit from incorporating the parabolic-tip inflow cannula design to maximize unloading of the left ventricle in ideal and nonoptimal conditions. PMID:27442862

  1. Analysis of the linear stability of compressible boundary layers using the PSE. [parabolic stability equations

    NASA Technical Reports Server (NTRS)

    Bertolotti, F. P.; Herbert, TH.

    1991-01-01

    The application of linearized parabolic stability equations (PSE) to compressible flow is considered. The effect of mean-flow nonparallelism is found to be weak on 2D waves and strong on 3D waves. Results for a single choice of free-stream parameters that corresponds to the atmospheric conditions at 15,000 m above sea level are presented.

  2. Time-parallel iterative methods for parabolic PDES: Multigrid waveform relaxation and time-parallel multigrid

    SciTech Connect

    Vandewalle, S.

    1994-12-31

    Time-stepping methods for parabolic partial differential equations are essentially sequential. This prohibits the use of massively parallel computers unless the problem on each time-level is very large. This observation has led to the development of algorithms that operate on more than one time-level simultaneously; that is to say, on grids extending in space and in time. The so-called parabolic multigrid methods solve the time-dependent parabolic PDE as if it were a stationary PDE discretized on a space-time grid. The author has investigated the use of multigrid waveform relaxation, an algorithm developed by Lubich and Ostermann. The algorithm is based on a multigrid acceleration of waveform relaxation, a highly concurrent technique for solving large systems of ordinary differential equations. Another method of this class is the time-parallel multigrid method. This method was developed by Hackbusch and was recently subject of further study by Horton. It extends the elliptic multigrid idea to the set of equations that is derived by discretizing a parabolic problem in space and in time.

  3. Fast Time and Space Parallel Algorithms for Solution of Parabolic Partial Differential Equations

    NASA Technical Reports Server (NTRS)

    Fijany, Amir

    1993-01-01

    In this paper, fast time- and Space -Parallel agorithms for solution of linear parabolic PDEs are developed. It is shown that the seemingly strictly serial iterations of the time-stepping procedure for solution of the problem can be completed decoupled.

  4. Microbial diversity in the deep-sea sediments of Iheya North and Iheya Ridge, Okinawa Trough.

    PubMed

    Zhang, Jian; Sun, Qing-lei; Zeng, Zhi-gang; Chen, Shuai; Sun, Li

    2015-08-01

    In this study, we analyzed the bacterial and archaeal diversities of the deep-sea sediments in Iheya North and Iheya Ridge, Okinawa Trough, using the high-throughput sequencing technology of Illumina MiSeq 2500 platform. Four samples (IN1, IN2, IR1 and IR2) were used in this study, of which IN1 and IN2 were located at regions close to and distant, respectively, from the active hydrothermal vents in Iheya North, while IR1 and IR2 were located at regions close to and distant, respectively, from the active hydrothermal vents in Iheya Ridge. The four samples were rich in different metal elements. Sequence analysis based on the V3-V4 regions of 16S rDNA gene obtained 170,363 taxon tags, including 122,920 bacterial tags and 47,433 archaeal tags, which cover 31 phyla, 50 classes, 59 orders, 87 families, and 138 genera. Overall, the microbial communities in all samples were dominated by bacteria, in which Proteobacteria was the largest phylum, followed by Chloroflexi, Firmicutes, Acidobacteria, Actinobacteria, Gemmatimonadetes, and Nitrospirae, which together accounted for 64.6% of the total taxon tags. In contrast to the high bacterial diversities, the archaeal diversity was low and dominated by Thaumarchaeota, which accounted for 22.9% of the total taxon tags. Comparative analysis showed that (i) IN2 and IR2 exhibited more microbial richness than IN1 and IR1, (ii) IR1 and IR2 exhibited higher microbial diversities than IN1 and IN2, (iii) samples from Iheya Ridge and Iheya North fell into two groups based on principle component analysis. Furthermore, microbes potentially involved in sulfur, nitrogen, and metal metabolism and cycling were detected in all samples. These results provide for the first time a comparative picture of the microbial diversities in the sediments of Iheya North and Iheya Ridge and indicate that geological features and distance from active hydrothermal vents likely play important roles in the shaping of microbial community structure. PMID:26211965

  5. Electrodynamics of the high-latitude trough: Its relationship with convection flows and field-aligned currents

    NASA Astrophysics Data System (ADS)

    Zou, Shasha; Moldwin, Mark B.; Nicolls, Michael J.; Ridley, Aaron J.; Coster, Anthea J.; Yizengaw, Endawoke; Lyons, Larry R.; Donovan, Eric F.

    2013-05-01

    We present a detailed case study of the electrodynamics of a high-latitude trough observed at ~ 12 UT (~1 MLT) on 8 March 2008 using multiple instruments, including incoherent scattering radar (ISR), GPS total electron content (TEC), magnetometers, and auroral imager. The electron density within the trough dropped as much as 80% within 6 minutes. This trough was collocated with a counterclockwise convection flow vortex, indicating divergent horizontal electric fields and currents. Together with a collocated dark area shown in auroral images, the observations provide strong evidence for an existence of downward field-aligned currents (FACs) collocated with the high-latitude trough. This is further supported by assimilative mapping of ionospheric electrodynamics results. In addition, the downward FACs formed at about the same time as a substorm onset and east of the Harang reversal, suggesting it is part of the substorm current wedge. It has long been a puzzle why this type of high-latitude trough predominantly occurs just east of the Harang reversal in the postmidnight sector. We suggest that the high-latitude trough is associated with the formation of downward FACs of the substorm current system, which usually occur just east of the Harang reversal. In addition, we find that the ionospheric electron temperature within the high latitude trough decreases in the F region while increasing in the E region. We discuss possible mechanisms responsible for the complex change in electron temperature, such as ion composition change and/or presence of downward FACs.

  6. Electrodynamics of the high-latitude trough: Its relationship with convection flows and field-aligned currents

    NASA Astrophysics Data System (ADS)

    Zou, S.; Moldwin, M.; Nicolls, M. J.; Ridley, A. J.; Coster, A. J.; Yizengaw, E.; Lyons, L. R.; Donovan, E.

    2012-12-01

    The ionospheric troughs are regions of remarkable electron density depression at subauroral and auroral latitudes, and significant electron density gradients exist at their boundaries. The high-latitude trough is defined as the low-density region present within the auroral oval or the polar cap. We present a detailed case study of the electrodynamics of a high-latitude trough observed at ~ 12 UT (~1 MLT) on March 8, 2008 using multiple instruments, including incoherent scattering radar (ISR), GPS total electron content (TEC), magnetometers and auroral imager. The electron density within the trough dropped as much as 80% within 6 minutes. This trough was collocated with a counter-clockwise convection flow vortex, indicating divergent horizontal electric fields and currents. Together with a collocated dark area shown in auroral images, the observations provide strong evidence for an existence of downward field-aligned currents (FACs) collocated with the high-latitude trough. This is further supported by Assimilative Mapping of Ionospheric Electrodynamics (AMIE) results. In addition, the downward FACs formed at about the same time as a substorm onset and east of the Harang reversal, suggesting it is part of the substorm current wedge. It has long been a puzzle why this type of high-latitude trough predominantly occurs just east of the Harang reversal in the post-midnight sector. We suggest that the high-latitude trough is associated with the formation of downward FACs of the substorm current system, which usually occur just east of the Harang reversal. In addition, we find that the ionospheric electron temperature within the high latitude trough decreases in the F region while increasing in the E region. We discuss possible processes responsible for the complex change in electron temperature, such as ion composition change and/or presence of downward FACs.

  7. Parabolic Dish Solar Thermal Power Annual Program Review Proceedings

    NASA Technical Reports Server (NTRS)

    Holbeck, H. J.

    1981-01-01

    The development and testing of concentrators, receivers, and power conversion units are reported. System design and development for engineering experiments are described. Economic analysis and market assessments for advanced development activities are discussed. Technology development issues and application/user needs are highlighted.

  8. Using parabolic mirrors for complete imaging of apple surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Automated imaging systems offer the potential to inspect the quality and safety of fruits consumed by the public. One problem that has hindered adoption of automated technologies has been the inability to image 100% of the surface of an individual fruit. A particular problem is that both the stem a...

  9. Implications of Plume-Trench Interaction Models for the Formation of Niue Trough

    NASA Astrophysics Data System (ADS)

    Pockalny, R. A.; Druken, K. A.; Kincaid, C. R.; Kelley, K. A.; Graham, D. W.

    2009-12-01

    The enigmatic Niue Trough is a 400-km long, 5000-m deep, scissor-shaped bathymetric depression (~500 m of local relief) located near the northern terminus of the Tonga Trench. Regional geophysical data and seafloor morphology suggest recent tectonic and volcanic activity along the trough. Reasonable explanations for this recent activity and morphology include: rifting associated with uplift along the peripheral bulge, tearing of the lithosphere due to differential subduction velocities, or reactivation of an existing rift. Recent laboratory models of the Tonga Trench - Samoa Hotspot system, however, provide new observations that indicate the Niue Trough may be the result of plume-trench interactions. Modeling results indicate an ascending plume head (e.g., Samoa Hotspot) would be drawn toward the subduction zone and would segregate into three parts. The majority of the plume head would be subducted with the down-going lithosphere, with one part located below the slab and a second part wrapping around the slab edge into the mantle wedge. Notably, the third part continues to rise and move laterally with plate motion until it impacts the base of the lithosphere (e.g., Pacific Plate) extending over a region corresponding to the northern third of the Tonga Trench. The coincidence between the location of the Niue Trough and the persistent plume head material at the base of the lithosphere from the laboratory models suggest a possible causal relationship. To test the plume head origin of the Niue Trough, we have performed 2D and 3D gravity models of the region. Our results indicate that the possibility of a 5-km thick, 30-km wide melt body (~20% melt) may be present along the length of the trough to account for the 50 mGal anomaly. Although the gravity models are equivocal and may be explained by crustal and sediment thickness variations, the melt anomaly scenario is the most consistent with available data and observations. This interpretation is also consistent with a

  10. Observations of the Fawn Trough Current over the Kerguelen Plateau from instrumented elephant seals

    NASA Astrophysics Data System (ADS)

    Roquet, Fabien; Park, Young-Hyang; Guinet, Christophe; Bailleul, Frédéric; Charrassin, Jean-Benoît

    2009-10-01

    Due to its great meridional extent and relatively shallow depths, the Kerguelen Plateau constitutes a major barrier to the eastward flowing Antarctic Circumpolar Current in the Indian sector of the Southern Ocean. While most of the Antarctic Circumpolar Current transport is deflected north of the Kerguelen Islands, the remainder (˜ 50 Sv, 1 Sv = 10 6 m 3 s - 1 ) must pass south of the islands, most probably through the Fawn and Princess Elizabeth Troughs. However, the paucity of finely resolved quasi-synoptic hydrographic data in this remote and infrequently sampled area has limited the progress in our knowledge of the regional circulation. Since 2004, a new approach using elephant seals from the Kerguelen Islands as autonomous oceanographic profilers has provided new information on the hydrography over the Kerguelen Plateau, covering the entire Antarctic Zone between the Polar Front and Antarctica, with a mean along-track resolution of about 25 km. These finely resolved bio-logged data revealed details of a strong northeastward current found across the Fawn Trough (sill depth: 2600 m; 56°S, 78°E). This so-called Fawn Trough Current transports cold Antarctic waters found mostly south of the Elan Bank, between the Ice Limit (58°S) and the Antarctic Divergence (64°S) in the eastern Enderby Basin, toward the Australian-Antarctic Basin. Our analysis also demonstrates that the Deep Western Boundary Current, which carries cold Antarctic water along the eastern flank of the southern Kerguelen Plateau collides with Fawn Trough Current at the outlet of the Fawn Trough sill. In other words, the Fawn Trough constitutes a veritable bottleneck, channelling the quasi-totality of the Antarctic Circumpolar flow found south of the Polar Front. Thanks to the unprecedented fine resolution of seal-borne data, a branch of flow centered at the Winter Water isotherm of 1 °C is also revealed along the northern escarpment of the Elan Bank, and then along the southern edge of Heard

  11. 3D Porosity Estimation of the Nankai Trough Sediments from Core-log-seismic Integration

    NASA Astrophysics Data System (ADS)

    Park, J. O.

    2015-12-01

    The Nankai Trough off southwest Japan is one of the best subduction-zone to study megathrust earthquake fault. Historic, great megathrust earthquakes with a recurrence interval of 100-200 yr have generated strong motion and large tsunamis along the Nankai Trough subduction zone. At the Nankai Trough margin, the Philippine Sea Plate (PSP) is being subducted beneath the Eurasian Plate to the northwest at a convergence rate ~4 cm/yr. The Shikoku Basin, the northern part of the PSP, is estimated to have opened between 25 and 15 Ma by backarc spreading of the Izu-Bonin arc. The >100-km-wide Nankai accretionary wedge, which has developed landward of the trench since the Miocene, mainly consists of offscraped and underplated materials from the trough-fill turbidites and the Shikoku Basin hemipelagic sediments. Particularly, physical properties of the incoming hemipelagic sediments may be critical for seismogenic behavior of the megathrust fault. We have carried out core-log-seismic integration (CLSI) to estimate 3D acoustic impedance and porosity for the incoming sediments in the Nankai Trough. For the CLSI, we used 3D seismic reflection data, P-wave velocity and density data obtained during IODP (Integrated Ocean Drilling Program) Expeditions 322 and 333. We computed acoustic impedance depth profiles for the IODP drilling sites from P-wave velocity and density data. We constructed seismic convolution models with the acoustic impedance profiles and a source wavelet which is extracted from the seismic data, adjusting the seismic models to observed seismic traces with inversion method. As a result, we obtained 3D acoustic impedance volume and then converted it to 3D porosity volume. In general, the 3D porosities show decrease with depth. We found a porosity anomaly zone with alteration of high and low porosities seaward of the trough axis. In this talk, we will show detailed 3D porosity of the incoming sediments, and present implications of the porosity anomaly zone for the

  12. Some Inferences on the Spreading Rate of the Ayu Trough, Equatorial Western Pacific

    NASA Astrophysics Data System (ADS)

    Lee, S.; Kim, S.; Choi, H.; Park, S.

    2012-12-01

    The Ayu Trough, located in the equatorial western Pacific, is the only divergent boundary surrounding the Philippine Sea plate. It has long been thought that detailed magnetic anomaly studies at the Ayu Trough may provide an important constraint on the past motion of the Philippine Sea plate with respect to the Caroline plate and subsequently with the Pacific plate. However, because the region lies near the magnetic equator and has spread more or less in the east-west direction, the determination of the relative motion using traditional method of matching total magnetic anomalies across the spreading axis has not been possible. Instead to estimate the spreading rate, the average increase in sediment thickness obtained from multi-channel seismic profiles has been used, which suggests that it opened at a half-spreading rate of 4.1 mm/yr during the last 25 Ma. This result places the Ayu Trough in the category of ultraslow-spreading mid-ocean ridge. However, there is a great uncertainty in this estimation because the sedimentation rate that was used in previous studies comes from a considerable distance away from the Ayu Trough, that is, from the middle of the Caroline plate where the sediment supply and transport conditions may be quite different. During the last decade, high-resolution bathymetric mapping and analyses of rocks dredged from more than 10 ultraslow-spreading ridges. As a result, a new picture of ultraslow-spreading ridges has emerged which differs from normal slow and fast spreading ridges. According to the new finding, the former are clearly more enriched in Rare Earth Elements (REE) than the latter. However, dredged rock samples from the Ayu Trough do not exhibit such signature, putting the earlier notion into question. Although it is difficult to determine the exact spreading rate, the geochemistry of rock samples obtained from the Ayu Trough suggests that the spreading occurred much more rapidly and over a shorter period of time than previously

  13. Chaotic motion of comets in near-parabolic orbit: Mapping aproaches

    NASA Astrophysics Data System (ADS)

    Liu, Jie; Sun, Yi-Sui

    1994-09-01

    There exist many comets with near-parabolic orbits in the solar system. Among various theories proposed to explain their origin, the Oort cloud hypothesis seems to be the most reasonable. The theory assumes that there is a cometary cloud at a distance 103 to 107 from the sun and that perturbing forces from planets or stars make orbits of some of these comets become the near-parabolic type. Concerning the evolution of these orbits under planetary perturbations, we can raise the question: Will they stay in the solar system forever or will they escape from it? This is an attractive dynamical problem. If we go ahead by directly solving the dynamical differential equations, we may encounter the difficulty of long-time computation. For the orbits of these comets are near-parabolic and their periods are too long to study on their long-term evolution. With mapping approaches the difficulty will be overcome. In another aspect, the study of this model has special meaning for chaotic dynamics. We know that in the neighborhood of any separatrix i.e. the trajectory with zero frequency of the uperturbed motion of a Hamiltonian system, some chaotic motions have to be expected. Actually, the simplest example of separatrix is the parabolic trajectory of the two-body problem which separates the bounded and unbounded motion. From this point of view, the dynamical study of near-parabolic motion is very important. Petrosky's elegant but more abstract deduction gives a Kepler mapping which describes the dynamics of the cometary motion. In this paper we derive a similar mapping directly and discuss its dynamical characters.

  14. Spike-adding in parabolic bursters: The role of folded-saddle canards

    NASA Astrophysics Data System (ADS)

    Desroches, Mathieu; Krupa, Martin; Rodrigues, Serafim

    2016-09-01

    The present work develops a new approach to studying parabolic bursting, and also proposes a novel four-dimensional canonical and polynomial-based parabolic burster. In addition to this new polynomial system, we also consider the conductance-based model of the Aplysia R15 neuron known as the Plant model, and a reduction of this prototypical biophysical parabolic burster to three variables, including one phase variable, namely the Baer-Rinzel-Carillo (BRC) phase model. Revisiting these models from the perspective of slow-fast dynamics reveals that the number of spikes per burst may vary upon parameter changes, however the spike-adding process occurs in an explosive fashion that involves special solutions called canards. This spike-adding canard explosion phenomenon is analysed by using tools from geometric singular perturbation theory in tandem with numerical bifurcation techniques. We find that the bifurcation structure persists across all considered systems, that is, spikes within the burst are incremented via the crossing of an excitability threshold given by a particular type of canard orbit, namely the true canard of a folded-saddle singularity. However there can be a difference in the spike-adding transitions in parameter space from one case to another, according to whether the process is continuous or discontinuous, which depends upon the geometry of the folded-saddle canard. Using these findings, we construct a new polynomial approximation of the Plant model, which retains all the key elements for parabolic bursting, including the spike-adding transitions mediated by folded-saddle canards. Finally, we briefly investigate the presence of spike-adding via canards in planar phase models of parabolic bursting, namely the theta model by Ermentrout and Kopell.

  15. Design of a Thermal Imaging Diagnostic Using 90-Degree, Off-Axis, Parabolic Mirrors

    SciTech Connect

    Malone, Robert M.; Becker, Steven A.; Dolan, Daniel H.; Hacking, Richard G.; Hickman, Randy J.; Kaufman, Morris I.; Stevens, Gerald D.; Turley, William D.

    2006-09-01

    Thermal imaging is an important, though challenging, diagnostic for shockwave experiments. Shock-compressed materials undergo transient temperature changes that cannot be recorded with standard (greater than ms response time) infrared detectors. A further complication arises when optical elements near the experiment are destroyed. We have designed a thermal-imaging system for studying shock temperatures produced inside a gas gun at Sandia National Laboratories. Inexpensive, diamond-turned, parabolic mirrors relay an image of the shocked target to the exterior of the gas gun chamber through a sapphire vacuum port. The 3000–5000-nm portion of this image is directed to an infrared camera which acquires a snapshot of the target with a minimum exposure time of 150 ns. A special mask is inserted at the last intermediate image plane, to provide dynamic thermal background recording during the event. Other wavelength bands of this image are split into high-speed detectors operating at 900–1700 nm, and at 1700–3000 nm for timeresolved pyrometry measurements. This system incorporates 90-degree, off-axis parabolic mirrors, which can collect low f/# light over a broad spectral range, for high-speed imaging. Matched mirror pairs must be used so that aberrations cancel. To eliminate image plane tilt, proper tip-to-tip orientation of the parabolic mirrors is required. If one parabolic mirror is rotated 180 degrees about the optical axis connecting the pair of parabolic mirrors, the resulting image is tilted by 60 degrees. Different focal-length mirrors cannot be used to magnify the image without substantially sacrificing image quality. This paper analyzes performance and aberrations of this imaging diagnostic.

  16. Activation of vegetated parabolic dunes into mobile barchans under potential environmental change scenarios

    NASA Astrophysics Data System (ADS)

    Yan, Na; Baas, Andreas C. W.

    2016-04-01

    Parabolic dunes are a quintessential example of the co-evolution of soil, landform, and vegetation, and they are found around the world, on coasts, river valleys, lake shores, and margins of deserts and steppes. These areas are often sensitive to changes in natural and anthropogenic forcings and socio-economic activities. Some studies have indicated parabolic dunes can lose vegetation and transform into barchan and transverse dunes by environmental change such as decreased precipitation or lowered water table, as well as anthropogenic stress such as increased burning and grazing. These transformations and shifts between states of eco-geomorphic systems may have significant implications on land management and social-economic development. This study utilises the Extended-DECAL - parameterised by field measurements of dune topography and vegetation characteristics combined with remote sensing - to explore how increases in drought stress, wind strength, and grazing stress may lead to the activation of stabilised parabolic dunes into highly mobile barchans. The modelling results show that the mobility of an initial parabolic dune at the outset of perturbations determines to a large extent the capacity of a system to absorb the environmental change, and a slight increase in vegetation cover of an initial parabolic dune can increase the activation threshold significantly. Plants with a higher deposition tolerance increase the activation threshold for the climatic impact and sand transport rate, whereas the erosion tolerance of plants influences the patterns of resulting barchans. The change in the characteristics of eco-geomorphic interaction zones may indirectly reflect the dune stability and predict an ongoing transformation, whilst the activation angle may be potentially used as a proxy of environmental stresses. In contrast to the natural environmental changes which tend to affect relatively weak and young plants, grazing stress can exert a broader impact on all

  17. 75 FR 20377 - Notice of Availability of the Draft Environmental Impact Statement for the Proposed Sonoran Solar...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-19

    ... use parabolic trough solar thermal technology to produce electrical power using steam turbine... and infrastructure, including power blocks and solar trough arrays (2,300 acres), evaporation ponds... County, Arizona, was published in the Federal Register on July 8, 2009 (74 FR 32641). The BLM held...

  18. Effect of electron-density gradients on propagation of radio waves in the mid-latitude trough. Master's thesis

    SciTech Connect

    Citrone, P.J.

    1991-01-01

    Partial contents of this thesis include: (1) Radio-wave propagation and the mid-latitude trough; (2) Ionospheric measurements; (3) Modification of time-dependent ionospheric model output with latitudinal electron-density profiles from digisonde trough depictions; (4) Ray-tracing simulations to examine ground range; and (5) Effects of three-dimensional gradients in electron density on radio-wave propagation in the trough region. Data is tabulated for geophysical conditions, solar activity level, geomagnetic activity level, conditions for vertical ray refraction to surface, and ray-tracing fixed-input conditions.

  19. Test and Analysis of an Inflatable Parabolic Dish Antenna

    NASA Technical Reports Server (NTRS)

    Gaspar, james L.; Sreekantamurthy, Tham; Mann, Troy; Behun, Vaughn; Romanofsky, Robert; Lambert, Kevin; Pearson, James

    2006-01-01

    NASA is developing ultra-lightweight structures technology for large communication antennas for application to space missions. With these goals in mind, SRS Technologies has been funded by NASA Glenn Research Center (GRC) to undertake the development of a subscale ultra-thin membrane inflatable antenna for deep-space applications. One of the research goals is to develop approaches for prediction of the radio frequency and structural characteristics of inflatable and rigidizable membrane antenna structures. GRC has teamed with NASA Langley Research Center (LaRC) to evaluate inflatable and rigidizable antenna concepts for potential space missions. GRC has completed tests to evaluate RF performance, while LaRC completed structural tests and analysis to evaluate the static shape and structural dynamic responses of a laboratory model of a 0.3 meter antenna. This paper presents the details of the tests and analysis completed to evaluate the radio frequency and structural characteristics of the antenna.

  20. Seismic imaging in laboratory trough laser Doppler vibrometry

    NASA Astrophysics Data System (ADS)

    Brito, Daniel; Poydenot, Valier; Garambois, Stéphane; Diaz, Julien; Bordes, Clarisse; Rolando, Jean-Paul

    2016-04-01

    Mimic near-surface seismic field measurements at a small scale, in the laboratory, under a well-controlled environment, may lead to a better understanding of wave propagation in complex media such as in geological materials. Laboratory experiments can help in particular to constrain and refine theoretical and numerical modelling of physical phenomena occurring during seismic propagation, in order to make a better use of the complete set of measurements recorded in the field. We have developed a laser Doppler vibrometer (laser interferometry) platform designed to measure non-contact seismic displacements (or velocities) of a surface. This technology enables to measure displacements as small as a tenth of a nanometer on a wide range of frequencies, from a few tenths to a few megahertz. Our experimental set-up is particularly suited to provide high-density spatial and temporal records of displacements on the edge of any vibrating material. We will show in particular a study of MHz wave propagation (excited by piezoelectric transducers) in cylindrical cores of typical diameter size around 10 cm. The laser vibrometer measurements will be first validated in homogeneous materials cylinders by comparing the measurements to a direct numerical simulation. Special attention will be given to the comparison of experimental versus numerical amplitudes of displacements. In a second step, we will conduct the same type of study through heterogeneous carbonate cores, possibly fractured. Tomographic images of velocity in 2D slices of the carbonate core will be derived based upon on the time of first arrival. Preliminary attempts of tomographic attenuation maps will also be presented based on the amplitudes of first arrivals. Experimental records will be confronted to direct numerical simulations and tomographic images will be compared to x-ray scanner imaging of the cylindrical cores.