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. 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.

  3. Current and Future Economics of Parabolic Trough Technology

    SciTech Connect

    Price, H.; Mehos, M.; Kutscher, C.; Blair, N.

    2007-01-01

    Solar energy is the largest energy resource on the planet. Unfortunately, it is largely untapped at present, in part because sunlight is a very diffuse energy source. Concentrating solar power (CSP) systems use low cost reflectors to concentrate the sun's energy to allow it to be used more effectively. Concentrating solar power systems are also well suited for large solar power plants that can be connected into the existing utility infrastructure. These two facts mean that CSP systems can be used to make a meaningful difference in energy supply in a relatively short period. CSP plants are best suited for the arid climates in the Southwestern United States, Northern Mexico, and many desert regions around the globe. A recent Western Governors' Association siting study [1] found that the solar potential in the U.S. Southwest is at least 4 times the total U.S. electric demand even after eliminating urban areas, environmentally sensitive areas, and all regions with a ground slope greater than 1%.While it is currently not practical to power the whole county from the desert southwest, only a small portion of this area is needed to make a substantial contribution to future U.S. electric needs. Many of the best sites are near existing high-voltage transmission lines and close to major power load centers in the Southwest (Los Angeles, Las Vegas, and Phoenix). In addition, the power provided by CSP technologies has strong coincidence with peak electric demand, especially in the Southwest where peak demand corresponds in large part to air conditioning loads. Parabolic troughs currently represent the most cost-effective CSP technology for developing large utility-scale solar electric power systems. These systems are also one of the most mature solar technologies, with commercial utility-scale plants that have been operating for over 20 years. In addition, substantial improvements have been made to the technology in recent years including improved efficiency and the addition of

  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 collectors for industrial and commercial applications

    SciTech Connect

    Gee, R.C.

    1997-06-01

    Industrial Solar Technology Corporation (IST) manufactures and installs parabolic trough solar energy systems for large-scale commercial and industrial applications. Parabolic trough collectors have advanced significantly over the last fifteen years and are the most developed and widely deployed type of solar concentrator. Collector efficiency has increased, installed costs have decreased, and system reliability has improved. These positive trends have moved parabolic trough technology to commercial viability in niche markets where energy costs are high and sunlight is abundant.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  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. 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.

  18. Optical, Energetic and Exergetic Analyses of Parabolic Trough Collectors

    NASA Astrophysics Data System (ADS)

    Murat, Öztürk; Nalan Çiçek, Bezir; Nuri, Özek

    2007-07-01

    Parabolic trough collectors generate thermal energy from solar energy. Especially, they are very convenient for applications in high temperature solar power systems. To determine the design parameters, parabolic trough collectors must be analysed with optical analysis. In addition, thermodynamics (energy and exergy) analysis in the development of an energy efficient system must be achieved. Solar radiation passes through Earth's atmosphere until it reaches on Earth's surface and is focused from the parabolic trough collector to the tube receiver with a transparent insulated envelope. All of them constitute a complex mechanism. We investigate the geometry of parabolic trough reflector and characteristics of solar radiation to the reflecting surface through Earth's atmosphere, and calculate the collecting total energy in the receiver. The parabolic trough collector, of which design parameters are given, is analysed in regard to the energy and exergy analysis considering the meteorological specification in May, June, July and August in Isparta/Turkey, and the results are presented.

  19. Guidelines for reporting parabolic trough solar electric system performance

    SciTech Connect

    Price, H.W.

    1997-06-01

    The purpose of this activity is to develop a generic methodology which can be used to track and compare the performance of parabolic trough power plants. The approach needs to be general enough to work for all existing and future parabolic trough plant designs, provide meaningful comparisons of year to year performance, and allow for comparisons between dissimilar plant designs. The approach presented here uses the net annual system efficiency as the primary metric for evaluating the performance of parabolic trough power plants. However, given the complex nature of large parabolic trough plants, the net annual system efficiency by itself does not adequately characterize the performance of the plant. The approach taken here is to define a number of additional performance metrics which enable a more comprehensive understanding of overall plant performance.

  20. 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.

  1. Second-generation parabolic trough solar energy systems optimization analysis

    NASA Astrophysics Data System (ADS)

    Peters, R. R.

    1982-04-01

    In the near future high-efficiency, low-cost, parabolic trough collectors will probably become available. The economic feasibility of these parabolic trough solar-energy systems is affected by many parameters which include component cost, load shape, fraction of the load supplied by solar energy, average temperature of the collector field and its axis of rotation, and for solar Rankine cogeneration systems, the electrical-to-thermal energy output ratio. The sensitivity of economic feasibility and system design to changes in these and other relevant parameters is discussed. System design and economics generally were found to be sensitive to component cost. They were also found to be quite sensitive to some of the other parameters in restricted ranges.

  2. 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.

  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. 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.

  6. 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.

  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. Novel second-stage solar concentrator for parabolic troughs

    NASA Astrophysics Data System (ADS)

    Collares-Pereira, Manuel; Mendes, Joao F.

    1995-08-01

    Conventional parabolic troughs can be combined with second stage concentrators (SSC), to increase temperature and pressure inside the absorber, making possible the direct production of steam, improving substantially the overall system efficiency and leading to a new generation of distributed solar power plants. To attain this objective, research is needed at the optical, thermodynamic, system control, and engineering levels. In what concerns the receiver of such a system, different practical solutions have been proposed recently and in the past for the geometry of the second stage concentrator: CPC type and others. In this work we discuss these solutions and we propose a new one, 100% efficient in energy collection while reaching a total concentration ratio which is almost 65% of the thermodynamic limit. This SSC has an asymmetric elliptical geometry, rendering possible a smooth solution for the reflectors while maintaining a reasonable size for the receiver.

  9. 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.

  10. 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.

  11. 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

  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. 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.

  14. A Process Heat Application Using Parabolic Trough Collector

    NASA Astrophysics Data System (ADS)

    Yılmaz, İbrahim Halil; Söylemez, Mehmet Sait; Hayta, Hakan; Yumrutaş, Recep

    A pilot study has been performed based on a heat process application that is designed, installed and tested at Gaziantep University to establish the technical and economic feasibility of high temperature solar-assisted cooking process. The system has been designed to be satisfying the process conditions integrated with parabolic trough solar collector (PTSC). It is primarily consists of the PTSC array, auxiliary heater, plate type heat exchanger, cooking system and water heating tanks. In the operation of the process heat application, the energy required to cook wheat (used as cooking material) has been supplied from solar energy which is transferred to heat transfer fluid (HTF) by heat exchanging units and finally discharged to water in order to produce bulgur. The performance parameters of the sub-systems and the process compatibility have been accomplished depending on the system operation. In addition that the system performance of the high temperature solar heat process has been presented and the recommendations on its improvement have been evaluated by performing an experimental study. As a result that the use of solar energy in process heat application has been projected and its contribution to economics view with respect to conventional cooking systems has been conducted.

  15. Heat and Chemical Exergy Analysis of Parabolic Trough Collector

    NASA Astrophysics Data System (ADS)

    Öztürk, M.; Üçgül, I.; Özek, N.

    2007-04-01

    Emissions of greenhouse gases and other pollutants, derived from the combustion of fossil fuels for heat and electricity generation, can be significantly reduced or even completely eliminated by substituting fossil fuels with a clean energy source, e.g. solar energy. However, solar radiation reaching the earth is diluted, intermittent, and, unequally distributed. These disadvantages can be overcome by converting solar energy into chemical energy carriers, i.e. solar fuels, such as solar hydrogen and solar methanol, which can be long-termed stored and long-ranged transported. Since the energy conversion efficiency of thermochemical processes is limited by the Carnot efficiency, the use of concentrated solar radiation as the source of high-temperature process heat provides a thermodynamically efficient path for the conversion of solar energy into chemical fuels. In this study, water-gas shift reaction in parabolic trough collector is evaluated with regarding the heat exergy and chemical exergy analyses and the results are given as tables and graphs.

  16. Sensitivity analysis on the effect of key parameters on the performance of parabolic trough solar collectors

    NASA Astrophysics Data System (ADS)

    Muhlen, Luis S. W.; Najafi, Behzad; Rinaldi, Fabio; Marchesi, Renzo

    2014-04-01

    Solar troughs are amongst the most commonly used technologies for collecting solar thermal energy and any attempt to increase the performance of these systems is welcomed. In the present study a parabolic solar trough is simulated using a one dimensional finite element model in which the energy balances for the fluid, the absorber and the envelope in each element are performed. The developed model is then validated using the available experimental data . A sensitivity analysis is performed in the next step in order to study the effect of changing the type of the working fluid and the corresponding Reynolds number on the overall performance of the system. The potential improvement due to the addition of a shield on the upper half of the annulus and enhancing the convection coefficient of the heat transfer fluid is also studied.

  17. 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.

  18. Nonimaging secondary concentrators for large rim angle parabolic troughs with tubular absorbers

    NASA Astrophysics Data System (ADS)

    Ries, Harald; Spirkl, Wolfgang

    1996-05-01

    For parabolic trough solar collectors with tubular absorbers, we design new tailored secondary concentrators. The design is applicable for any rim angle of a parabolic reflector. With the secondary, the concentration can be increased by a factor of more than 2 with a compact secondary reflector consisting of a single piece, even for the important case of a rim angle of 90 deg. The parabolic reflector can be used without changes; the reduced absorber is still tubular but smaller than the original absorber and slightly displaced toward the primary. concentrators, solar trough collectors, tailored reflectors.

  19. 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.

  20. 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.

  1. 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.

  2. Validation of the FLAGSOL parabolic trough solar power plant performance model

    SciTech Connect

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

    1994-10-01

    This paper describes the results of a validation of the FLAGSOL parabolic trough solar power plant performance model. The validation was accomplished by simulating an operating solar electric generating system (SEGS) parabolic trough solar thermal power plant and comparing the model output results with actual plant operating data. This comparison includes instantaneous, daily, and annual total solar thermal electric output, gross solar electric generation, and solar mode parasitic electric consumption. The results indicate that the FLAGSOL model adequately predicts the gross solar electric output of an operating plant, both on a daily and an annual basis.

  3. SkyFuel Parabolic Trough Optical Efficiency Testing: Cooperative Research and Development Final Report, CRADA Number CRD-08-00266

    SciTech Connect

    Gawlik, K.

    2010-08-01

    Tested parabolic trough products provided by SkyFuel, a manufacturer of parabolic trough systems in the concentrating solar thermal power industry. The testing evaluated the performance of the system at the Optical Efficiency Test Loop at Solar Industrial Mesa Top Area.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Revisiting Parabolic Trough Concentrators for Industrial Process Heat in the United States

    SciTech Connect

    Turchi, Craig S.; Kurup, Parthiv; Zhu, Guangdong

    2016-06-03

    After significant interest in the 1970s, but relatively few deployments, the use of concentrating solar collectors for thermal applications, including enhanced oil recovery, desalination, and industrial process heat (IPH), is again increasing in global interest. In particular, recent advances in collector design and manufacturing have led to reduced cost per square meter of aperture area. In this study, analysis of a modern parabolic trough that is suited for use in small solar IPH (SIPH) applications predicts that the installed solar field cost can be as low as $170/m2. A slightly higher cost of $200/m2 is estimated for facilities typical of a SIPH plant size. Full project costs will include additional costs for contingency, piping and heat exchanger interface, and project indirect costs. The cost for solar-generated heat by SIPH is quantified by defining the levelized cost of heat (LCOH). California offers a favorable environment for SIPH given its good insolation, gas prices typically higher than the national average, and policies promoting solar-thermal deployment. Given historically low gas prices, competing with natural gas remains the primary challenge to deployment. However, this study finds that the solar LCOH for many regions in California is lower than the LCOH from natural gas, using a representative installed solar hardware price and the average price for industrial natural gas in California. Lastly, modification are in progress to the parabolic trough model within NREL's System Advisor Model (SAM) to allow users to more easily predict performance for these steam-generation applications.

  11. 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.

  12. Performance Evaluation of a Nanofluid-Based Direct Absorption Solar Collector with Parabolic Trough Concentrator.

    PubMed

    Xu, Guoying; Chen, Wei; Deng, Shiming; Zhang, Xiaosong; Zhao, Sainan

    2015-12-04

    Application of solar collectors for hot water supply, space heating, and cooling plays a significant role in reducing building energy consumption. For conventional solar collectors, solar radiation is absorbed by spectral selective coating on the collectors' tube/plate wall. The poor durability of the coating can lead to an increased manufacturing cost and unreliability for a solar collector operated at a higher temperature. Therefore, a novel nanofluid-based direct absorption solar collector (NDASC) employing uncoated collector tubes has been proposed, and its operating characteristics for medium-temperature solar collection were theoretically and experimentally studied in this paper. CuO/oil nanofluid was prepared and used as working fluid of the NDASC. The heat-transfer mechanism of the NDASC with parabolic trough concentrator was theoretically evaluated and compared with a conventional indirect absorption solar collector (IASC). The theoretical analysis results suggested that the fluid's temperature distribution in the NDASC was much more uniform than that in the IASC, and an enhanced collection efficiency could be achieved for the NDASC operated within a preferred working temperature range. To demonstrate the feasibility of the proposed NDASC, experimental performances of an NDASC and an IASC with the same parabolic trough concentrator were furthermore evaluated and comparatively discussed.

  13. 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)

  14. 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.

  15. Performance Evaluation of a Nanofluid-Based Direct Absorption Solar Collector with Parabolic Trough Concentrator

    PubMed Central

    Xu, Guoying; Chen, Wei; Deng, Shiming; Zhang, Xiaosong; Zhao, Sainan

    2015-01-01

    Application of solar collectors for hot water supply, space heating, and cooling plays a significant role in reducing building energy consumption. For conventional solar collectors, solar radiation is absorbed by spectral selective coating on the collectors’ tube/plate wall. The poor durability of the coating can lead to an increased manufacturing cost and unreliability for a solar collector operated at a higher temperature. Therefore, a novel nanofluid-based direct absorption solar collector (NDASC) employing uncoated collector tubes has been proposed, and its operating characteristics for medium-temperature solar collection were theoretically and experimentally studied in this paper. CuO/oil nanofluid was prepared and used as working fluid of the NDASC. The heat-transfer mechanism of the NDASC with parabolic trough concentrator was theoretically evaluated and compared with a conventional indirect absorption solar collector (IASC). The theoretical analysis results suggested that the fluid’s temperature distribution in the NDASC was much more uniform than that in the IASC, and an enhanced collection efficiency could be achieved for the NDASC operated within a preferred working temperature range. To demonstrate the feasibility of the proposed NDASC, experimental performances of an NDASC and an IASC with the same parabolic trough concentrator were furthermore evaluated and comparatively discussed. PMID:28347112

  16. 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.

  17. An Optical Characterization Technique for Parabolic Trough Solar Collectors Using Images of the Absorber Reflection

    NASA Astrophysics Data System (ADS)

    Owkes, Jeanmarie Kathleen

    As the concentrating solar power industry competes to develop a less-expensive parabolic trough collector, assurance is needed that new parabolic trough collectors maintain accurate optical alignment. Previous optical characterization techniques are either too slow, ill-suited for field testing, or do not allow the collector to be tested in realistic orientations. The Observer method presented here enables the rapid optical characterization of parabolic trough collectors in any orientation in the field. The Observer method directly measures the combined optical angular errors in the reflector surface shape and the absorber position, which can be separated into its two components: reflector surface slope and absorber misalignment. The data acquisition requires the placement of photogrammetry targets on and around the collector. Multiple photographs of the absorber and its reflection are taken with a digital camera from different angles with respect to the collector. The images are processed to determine the camera location of each image using photogrammetry bundle analysis. The absorber and its reflection are found in the photographs using image-processing techniques. A Monte Carlo uncertainty model was developed to determine the uncertainty in the Observer measurements. The uncertainty was estimated for a wide array of measurement test scenarios to demonstrate the user's control over the measurement uncertainty. To validate the Observer method, the absorber alignment technique was compared to traditional photogrammetry; the absorber position measured with the two methods compared with a root-mean-square difference of 1.5 mm in the transverse direction and 0.86 mm along the optical axis. The reflector surface slope error measurement was compared to both VSHOT and SOFAST, two well-established optical characterization tools, by measuring a single reflector panel in the laboratory. The VSHOT and SOFAST measurements agreed with the Observer with a root

  18. Optical testing of a parabolic trough solar collector by a null screen with stitching

    NASA Astrophysics Data System (ADS)

    Moreno-Oliva, V., I.; Campos-Garcia, M.; Granados-Agustin, F.; Arjona-Pérez, M. J.; Díaz-Uribe, R.; Avendaño-Alejo, M.

    2009-06-01

    In this work we report a method for testing a parabolic trough solar collector (PTSC) based on the null screen principles. For surfaces with symmetry of revolution a cylindrical null screen is used, now, for testing the PTSC we use a flat null screen. The design of the null screen with ellipsoidal spots is described; its image, which is formed by reflection on the test surface, becomes an exact square array of circular spots if the surface is perfect. Any departure from this geometry is indicative of defects on the surface. The flat null screen design and the surface evaluation algorithm are presented. Here the surface is tested in sections and the evaluation of the shape of the surface is performed with stitching method. Results of the evaluation for a square PTSC with 1000 mm by side (F/0.49) are shown.

  19. Analysis of defects on the slopes on a parabolic trough solar collector with null-screens

    NASA Astrophysics Data System (ADS)

    Campos-García, Manuel; Huerta-Carranza, Oliver; Díaz-Uribe, Rufino; Moreno-Oliva, Víctor I.

    2015-09-01

    The null-screen method has been used to test aspheric surfaces, among them the surface of a parabolic trough solar collector (PTSC). This geometrical method measures the slope of the test surface and by a numerical integration procedure the shape of the test surface can be obtained. In this work, through some numerical simulations sinusoidal deformations with different amplitudes and spatial periods are introduced on PTSC surfaces. Then, an analysis of the deformations of the reflected images of a null-screen by the PTSC surface due to defects on the surface is performed. This procedure allows to validate the kind and magnitude of the surface deformations that can be measured with the proposed method. Also, an analysis of the advantages and limitations of the null-screen testing method will be discussed.

  20. Heat transfer enhancement in a parabolic trough solar receiver using longitudinal fins and nanofluids

    NASA Astrophysics Data System (ADS)

    Amina, Benabderrahmane; Miloud, Aminallah; Samir, Laouedj; Abdelylah, Benazza; Solano, J. P.

    2016-10-01

    In this paper, we present a three dimensional numerical investigation of heat transfer in a parabolic trough collector receiver with longitudinal fins using different kinds of nanofluid, with an operational temperature of 573 K and nanoparticle concentration of 1% in volume. The outer surface of the absorber receives a non-uniform heat flux, which is obtained by using the Monte Carlo ray tracing technique. The numerical results are contrasted with empirical results available in the open literature. A significant improvement of heat transfer is derived when the Reynolds number varies in the range 2.57×104 ≤ Re ≤ 2.57×105, the tube-side Nusselt number increases from 1.3 to 1.8 times, also the metallic nanoparticles improve heat transfer greatly than other nanoparticles, combining both mechanisms provides better heat transfer and higher thermo-hydraulic performance.

  1. Freeform lens design to achieve 1000X solar concentration with a parabolic trough reflector

    NASA Astrophysics Data System (ADS)

    Wheelwright, Brian M.; Angel, Roger; Coughenour, Blake

    2014-12-01

    Line-focus parabolic trough mirrors for solar thermal generation cannot produce the high concentration required for concentrating photovoltaic (CPV) systems. We describe a freeform lens array with toroidal symmetry which intercepts the low-concentration line focus to produce a series of elongated, high-concentration foci. The design employs 2D Kӧhler illumination to improve the acceptance angle in one direction. The two-stage concentrator has 1000X average geometric concentration with an acceptance angle of +/-1.49° in the azimuthal direction and +/-0.29° in the elevation direction. Preliminary results of a prototype roll-forming process are shown in thermoplastics and B270 glass.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Effect of porous disc receiver configurations on performance of solar parabolic trough concentrator

    NASA Astrophysics Data System (ADS)

    Ravi Kumar, K.; Reddy, K. S.

    2012-03-01

    In this article, heat transfer enhancement of line focus solar collector with porous disc receiver is studied with water and therminol oil. A three dimensional (3-D) numerical simulation of porous disc enhanced receiver is carried out using commercial CFD software Fluent 6.3 to evolve the optimum configuration. The 3-D numerical model is solved by renormalization-group based k-ɛ turbulent model associated with standard wall function. The effect of porous disc receiver configurations (solid disc at bottom; porous disc at bottom; porous disc at top; and alternative porous disc) on performance of the trough concentrator is investigated. The effect of porous disc geometric parameters (φ, θ, W, H and t) and fluid parameters (Pr and m) on heat transfer enhancement of the receiver is also studied. The numerical simulation results show that the flow pattern around the solid and porous discs are entirely different and it significantly influences the local heat transfer coefficient. The porous disc receiver experiences low pressure drop as compared to that of solid disc receiver due to less obstruction. The optimum configuration of porous disc receiver enhances the heat transfer rate of 221 W m-1 and 13.5% with pumping penalty of 0.014 W m-1 for water and for therminol oil-55, heat transfer rate enhances of 575 W m-1 and 31.4% with pumping penalty of 0.074 W m-1 as compared to that of tubular receiver at the mass flow rate of 0.5 kg s-1. The Nusselt number and friction factor correlations are proposed for porous disc receiver to calculate heat transfer characteristics. The porous disc receiver can be used to increase the performance of solar parabolic trough concentrator.

  7. 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.

  8. Status of the current parabolic dish technology

    NASA Technical Reports Server (NTRS)

    Sumrall, C.

    1981-01-01

    Vu-graphs are presented that show that point focus distributed receiver distributed generation systems are cost competitive with current utilities. System cost caveats and typical power module costs are described. Major problems inhibiting commercialization of the parabolic dish technology were reviewed.

  9. Second law analysis and optimization of a parabolic trough receiver tube for direct steam generation

    NASA Astrophysics Data System (ADS)

    Nolte, H. C.; Bello-Ochende, T.; Meyer, J. P.

    2015-06-01

    Entropy generation in the receiver tube of a parabolic trough solar collector can mainly be attributed to the fluid friction and finite temperature differences. The contribution of each of these components is investigated under different circumstances. Mass flow rates, tube diameters and operating pressures are investigated to obtain good guidelines for receiver tube and plant design. Operating pressures between 3 MPa (saturation temperature of 233.9 °C) and 9 MPa (saturation temperature of 303.3 °C) were investigated. Results show that small diameters can result in excessive fluid friction, especially when the mass flow rates are high. For most cases, tube diameters beyond 20 mm will exclusively be subject to entropy generation due to finite temperature differences, and entropy generation due to fluid friction will be small to negligible. Increasing the concentration ratio will decrease entropy generation, due to a higher heat flux per unit meter. This will ultimately result in shorter receiver tube lengths. From a simulated annealing optimization it was seen that if the diameter is increased, the entropy generation can be lowered, provided that the concentration ratio is kept constant. However, beyond a certain point gains in minimizing the entropy generation become negligible. The optimal operating pressure will generally increase if the mass flow rate is increased. Finally it was seen that higher operating pressures are more advantageous when the entropy generation minimization is considered in conjunction with the work output.

  10. Thermal performance and stress analyses of the cavity receiver tube in the parabolic trough solar collector

    NASA Astrophysics Data System (ADS)

    Cao, F.; Li, Y.; Wang, L.; Zhu, T. Y.

    2016-08-01

    A light ray tracing model and a heat transfer model were built to analyse the heat flux distribution and heat transfer in a 1m cavity receiver tube with Parabolic Trough Collectors as the concentrator. The numerical methods were used to simulate the thermal stress and deformation of the receiver tube. The temperature fields of the receiver tube and the thermal stress distribution in the steel tube at the cross section and along the fluid flowing direction were presented. It is obtained from this study that non-uniform heat flux distribution is absorbed at the receiver tube outer surface due to the structure of the cavity receiver tube. Temperature fields in the steel receiver tube at the inlet and the outlet match well with the incident solar radiation. An eccentric circle temperature gradient is observed at cross section of the outlet fluid. The equivalent stress is a complex result of solar heating flux, energy transfer inside the PTC and the fluid and steel characteristics. Highest deformation is 3.1mm at 0.82m. On increasing the fluid mass flow rate, higher fluid mass flow rate results in higher equivalent stress along the absorber tube.

  11. Design of a single flat null-screen for testing a parabolic trough solar collector

    NASA Astrophysics Data System (ADS)

    Moreno-Oliva, Víctor Iván; Campos-García, Manuel; Román-Hernández, Edwin; Santiago-Alvarado, Agustín

    2014-11-01

    We present a null-screen design for testing the shape quality of the reflecting surface of a parabolic trough solar collector (PTSC). This technique is inexpensive, the whole surface is tested at once, and it is easy to implement. For this, we propose the design of a flat null-screen perpendicular to the optical axis of the PTSC in such a way that it allows testing of the full aperture; we compute the caustic associated with the reflected light rays on the desired surface and analyze the parameters that determine the null-screen dimensions. Additionally, we perform a numerical simulation to analyze the accuracy of the method by introducing random displacement errors into the measured data. Accuracies >0.35 mrad were found to evaluate the quality of surfaces with this method. The errors in the determination of the coordinates of the centroids of the reflected images must be measured with an accuracy >0.5 pixels, and the errors in the coordinates of the spots of the null-screen must be <0.5 mm.

  12. 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.

  13. High concentration two-stage optics for parabolic trough solar collectors with tubular absorber and large rim angle

    SciTech Connect

    Collares-Pereira, M. ); Gordon, J.M. ); Rabl, A. ); Winston, R. )

    1991-01-01

    A new two-stage optical design is proposed for parabolic trough solar collectors with tubular absorbers. It can boost the concentration ratio by a factor of 2.5 relative to the conventional design, while maintaining the large rim angles (i.e., low nominal f-numbers) that are desirable for practical and economical reasons. The second state involves asymmetric nonimaging concentrators of the CPC type, facing segments of the parabolic first stage. The second stage can be accommodated inside an evacuated receiver, allowing the use of first-surface silvered reflectors. The low heat loss of this design opens the possibility of producing steam at temperatures and pressures of conventional power plants, using only one-axis tracking. The improvement in conversion efficiency would be substantial.

  14. An analysis of the technical and economic performance of a parabolic trough concentrator for solar industrial process heat application

    NASA Astrophysics Data System (ADS)

    Clark, J. A.

    1982-09-01

    Design parameters and economic projections of importance to the commercial realization of mass-produced parabolic trough solar concentrators as industrial heat suppliers are presented. Numerical formulas are defined for obtaining a figure of merit for the thermal efficiency of a concentrator, taking into account the reflectivity, the mirror-receiver intercept factor, the end loss factor, tracking and misalignment errors, the absorptivity-transmissivity product at normal incidence of the receiver tube and its glass envelope, and durability. An economic analysis which includes all costs, tax write-offs, comparisons with conventional fuels, inflation rate, time of borrowing, maintenance, profits, and conversion efficiencies is developed. It was determined that the trough systems will become competitive in the U.S. when installed costs are $15.79/sq ft over a 10-yr investment period

  15. 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.

  16. 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

  17. Sensitivity analysis in the test of a parabolic trough solar collector (PTSC) with flat null-screens

    NASA Astrophysics Data System (ADS)

    Campos-García, Manuel; Huerta-Carranza, Oliver; Díaz-Uribe, José Rufino; Moreno-Oliva, Víctor Iván.; Santiago-Alvarado, Agustín.; Peña-Conzueloa, Andrés.

    2016-09-01

    In this work we proposed a flat null-screen method to test parabolic trough solar collectors (PTSC). The null-screen testing method measures the slope of the test surface and by a numerical integration procedure the shape of the test surface can be obtained. In this work, we show that the test can be sensitive to small surface deformations, such as those caused by sinusoidal deformations with different amplitudes and spatial periods introduced on the PTSC surface. These calculations also show that the attainable theoretical slope accuracy in the rms sense is about 0.34 mrad. This value was obtained under the assumption that is possible to achieve a 1-pixel resolution on the measurement of the position departures of the centroids of the targets of the null-screen.

  18. Doubling the concentration of one-axis tracking parabolic trough collectors by a new second-stage design

    NASA Astrophysics Data System (ADS)

    Brunotte, Martin; Goetzberger, Adolf; Blieske, Ulf

    1994-09-01

    Economic operation of high-efficiency concentrator solar cells requires solar concentration ratios which up to now can only be achieved with two-axis tracking. In this paper we present a two-stage concentrator approaching concentration ratios up to 300X while being tracked around only one polar axis. Its principle is as follows: A parabolic trough focusses the direct solar radiation onto a line parallel to the polar tracking axis. The half rim angle of this first concentrating stage is chosen to be equal to the sun's maximum declination of 23.5 degree(s). The second stage consists of a row of dielectric, nonimaging 3D-concentrators, which couple the concentrated light directly into square solar cells. The proposed design makes use of the limited divergence of +/- 23.5 degree(s)) in the NS-direction which still can be concentrated by a factor of n/sin(23.5 degree(s)). The performance of the system depends sensitively on how well the angular acceptance characteristic of the second stage matches with the square-shaped angular irradiance distribution in the focal line of the parabolic trough. A new concentrator profile has been found that exhibits an almost ideal square acceptance characteristic with a very sharp cut-off. It is longer than the standard CPC and its slope is reduced towards the exit of the concentrator. A prototype two-stage concentrator has been constructed with a total geometrical concentration of 214X. In outdoor measurements a total optical efficiency of 77.5% was obtained.

  19. 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.

  20. 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.

  1. 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.

  2. Second Generation Novel High Temperature Commercial Receiver & Low Cost High Performance Mirror Collector for Parabolic Solar Trough

    SciTech Connect

    Stettenheim, Joel

    2016-02-29

    Norwich Technologies (NT) is developing a disruptively superior solar field for trough concentrating solar power (CSP). Troughs are the leading CSP technology (85% of installed capacity), being highly deployable and similar to photovoltaic (PV) systems for siting. NT has developed the SunTrap receiver, a disruptive alternative to vacuum-tube concentrating solar power (CSP) receivers, a market currently dominated by the Schott PTR-70. The SunTrap receiver will (1) operate at higher temperature (T) by using an insulated, recessed radiation-collection system to overcome the energy losses that plague vacuum-tube receivers at high T, (2) decrease acquisition costs via simpler structure, and (3) dramatically increase reliability by eliminating vacuum. It offers comparable optical efficiency with thermal loss reduction from ≥ 26% (at presently standard T) to ≥ 55% (at high T), lower acquisition costs, and near-zero O&M costs.

  3. 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)

  4. Experimental study of heat transfer in parabolic trough solar receiver: Using two different heat transfer fluids

    NASA Astrophysics Data System (ADS)

    Tahtah, Reda; Bouchoucha, Ali; Abid, Cherifa; Kadja, Mahfoud; Benkafada, Fouzia

    2017-02-01

    The sun provides the earth with huge amounts of energy that can be exploited in various forms. Its exploitation can be done by using a parabolic through solar concentrator integrated with thermal storage tank, that we already made, and it is our main study. This study obviously requires special attention to the effect of the parameters of the fluids, in addition to thermal performances of this system. To do this, we studied the thermal behavior of this concentrator, and by choosing the summer period because of its stable illumination (clear sky). Before starting the test, it is necessary to check the flow circuit and the storage tank which completely filled with fluid, started the measures on the morning, the concentrator directed towards the sun until the sunset, we recorded the variation of different temperatures such as Tin, Tout, Tsur, Tfluid and Tamb. We have compared the evaluation of temperatures between water and thermal oil in order to determine the best thermal behavior and the importance of the specific heat of each fluid. The obtained results of this paper show that by using water inside the receiver, we obtained better performance than by using oil. It can be observed that the oil temperature increasing rapidly compared to water, however, water temperature takes long time to cool down compared to the first fluid which will help in the storage of heat.

  5. 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.

  6. Experimental Performance of a Solar Thermoelectric Cogenerator Comprising Thermoelectric Modules and Parabolic Trough Concentrator without Evacuated Tube

    NASA Astrophysics Data System (ADS)

    Miao, L.; Kang, Y. P.; Li, C.; Tanemura, S.; Wan, C. L.; Iwamoto, Y.; Shen, Y.; Lin, H.

    2015-06-01

    A prototype practical solar-thermoelectric cogenerator composed of (1) a primary component of a pile of solar-selective absorber (SSA) slab, thermoelectric (TE) modules, and a depressed water flow tube (multichannel cooling heat sink, MCS), and (2) a parabolic trough concentrator with aperture area of 2m × 2m and east-west focal axis was constructed. Its cogeneration performance under the best climatic and solar insolation conditions in Guangzhou, China was tested. For simplicity, the evacuated glass tube to cover the primary component was eliminated from the system. Six Bi2Te3 TE modules were arranged in series, directly bonded to the rear surface of the solar absorber slab. The hot-side temperature of the TE module reached up to 152°C. The experimentally obtained instantaneous results for the solar to electrical conversion efficiency, heat exchange coefficient of the MCS, and overall system efficiency under the best environmental and solar insolation conditions were about 1.14%, 56.1%, and 49.5%, respectively. To justify these values, an equivalent thermal network diagram based on a single-temperature-node heat transfer model representing the respective system components was used to analyze the thermal transfer and losses of the system. Finally, electrical power of 18° W was generated, with 2 L/min of hot water at 37°C being produced and stored in the insulated container.

  7. 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.

  8. 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.

  9. Solar multiple optimization for a solar-only thermal power plant, using oil as heat transfer fluid in the parabolic trough collectors

    SciTech Connect

    Montes, M.J.

    2009-12-15

    Usual size of parabolic trough solar thermal plants being built at present is approximately 50 MW{sub e}. Most of these plants do not have a thermal storage system for maintaining the power block performance at nominal conditions during long non-insolation periods. Because of that, a proper solar field size, with respect to the electric nominal power, is a fundamental choice. A too large field will be partially useless under high solar irradiance values whereas a small field will mainly make the power block to work at part-load conditions. This paper presents an economic optimization of the solar multiple for a solar-only parabolic trough plant, using neither hybridization nor thermal storage. Five parabolic trough plants have been considered, with the same parameters in the power block but different solar field sizes. Thermal performance for each solar power plant has been featured, both at nominal and part-load conditions. This characterization has been applied to perform a simulation in order to calculate the annual electricity produced by each of these plants. Once annual electric energy generation is known, levelized cost of energy (LCOE) for each plant is calculated, yielding a minimum LCOE value for a certain solar multiple value within the range considered. (author)

  10. 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

  11. 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.

  12. Preliminary study on optimization of pH, oxidant and catalyst dose for high COD content: solar parabolic trough collector.

    PubMed

    Singh, Chandan; Chaudhary, Rubina; Gandhi, Kavita

    2013-01-22

    In the present study, solar photocatalytic oxidation has been investigated through laboratory experiments as an alternative to conventional secondary treatment for the organic content reduction of high COD wastewater. Experiments have been performed on synthetic high COD wastewater for solar photocatalytic oxidation using a parabolic trough reactor. Parameters affecting the oxidation of organics have been investigated.The experimental design followed the sequence of dark adsorption studies of organics, followed by photolytic studies (in absence of catalyst) and finally photocatalytic studies in presence and absence of additional oxidant (H2O2). All the experimental studies have been performed at pH values of 2, 4, 6,8,10 and the initial pH value of the wastewater (normal pH). For photocatalytic studies, TiO2 has been used as a photocatalyst. Optimization of catalyst dose, pH and H2O2 concentration has been done. Maximum reduction of organic content was observed at the normal pH value of the wastewater (pH = 6.8). The reaction rate was significantly enhanced in presence of hydrogen peroxide. The optimum pH other than the Normal was in the alkaline range. Acidic pH was not found to be favourable for organic content reduction. pH was found to be a dominant factor affecting reaction rate even in presence of H2O2 as an additional oxidant. Also, the solar detoxification process was effective in treating a waste with a COD level of more than 7500 mg/L, which is a otherwise a difficult waste to treat. It can therefore be used as a treatment step in the high organic wastewater treatment during the primary stage also as it effectively reduces the COD content by 86%.

  13. Preliminary study on optimization of pH, oxidant and catalyst dose for high COD content: solar parabolic trough collector

    PubMed Central

    2013-01-01

    In the present study, solar photocatalytic oxidation has been investigated through laboratory experiments as an alternative to conventional secondary treatment for the organic content reduction of high COD wastewater. Experiments have been performed on synthetic high COD wastewater for solar photocatalytic oxidation using a parabolic trough reactor. Parameters affecting the oxidation of organics have been investigated. The experimental design followed the sequence of dark adsorption studies of organics, followed by photolytic studies (in absence of catalyst) and finally photocatalytic studies in presence and absence of additional oxidant (H2O2). All the experimental studies have been performed at pH values of 2, 4, 6,8,10 and the initial pH value of the wastewater (normal pH). For photocatalytic studies, TiO2 has been used as a photocatalyst. Optimization of catalyst dose, pH and H2O2 concentration has been done. Maximum reduction of organic content was observed at the normal pH value of the wastewater (pH = 6.8). The reaction rate was significantly enhanced in presence of hydrogen peroxide. The optimum pH other than the Normal was in the alkaline range. Acidic pH was not found to be favourable for organic content reduction. pH was found to be a dominant factor affecting reaction rate even in presence of H2O2 as an additional oxidant. Also, the solar detoxification process was effective in treating a waste with a COD level of more than 7500 mg/L, which is a otherwise a difficult waste to treat. It can therefore be used as a treatment step in the high organic wastewater treatment during the primary stage also as it effectively reduces the COD content by 86%. PMID:23369352

  14. A comparison of prototype compound parabolic collector-reactors (CPC) on the road to SOLARDETOX technology.

    PubMed

    Funken, K H; Sattler, C; Milow, B; De Oliveira, L; Blanco, J; Fernández, P; Malato, S; Brunott, M; Dischinge, N; Tratzky, S; Musci, M; de Oliveira, J C

    2001-01-01

    Solar photocatalytic detoxification of non-biodegradable chlorinated hydrocarbon solvents (NBCS) is carried out in different concentrating and non concentrating devices using TiO2 as a photocatalyst fixed on the inner surface of the reaction tubes or as a slurry catalyst which has to be removed from the treated water. The reaction is most effective using 200 mg/l of TiO2 as a slurry in a non concentrating CPC reactor. The concentrating parabolic trough reactor has a poor activity because of its minor irradiated reactor surface. Catalyst coated glass tubes are less efficient then the used slurry catalyst. Their advantage is that no catalyst has not to be removed from the treated water and there is no loss of activity during treatment. Yet their physical stability is not sufficient to be competitive to the slurry catalyst. Nevertheless the degradation results are very promising and will possibly lead to commercial applications of this technology.

  15. Feasibility Study on the Use of a Solar Thermoelectric Cogenerator Comprising a Thermoelectric Module and Evacuated Tubular Collector with Parabolic Trough Concentrator

    NASA Astrophysics Data System (ADS)

    Miao, L.; Zhang, M.; Tanemura, S.; Tanaka, T.; Kang, Y. P.; Xu, G.

    2012-06-01

    We have designed a new solar thermoelectric cogeneration system consisting of an evacuated tubular solar collector (ETSC) with a parabolic trough concentrator (PTC) and thermoelectric modules (TEMs) to supply both thermal energy and electricity. The main design concepts are (1) the hot side of the TEM is bonded to the solar selective absorber installed in an evacuated glass tube, (2) the cold side of the TEM is also bonded to the heat sink, and (3) the outer circulated water is heated by residual solar energy after TEM generation. We present an example solar thermal simulation based on energy balance and heat transfer as used in solar engineering to predict the electrical conversion efficiency and solar thermal conversion efficiency for different values of parameters such as the solar insolation, concentration ratio, and TEM ZT values.

  16. 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

  17. Optical design of two-axes parabolic trough collector and two-section Fresnel lens for line-to-spot solar concentration.

    PubMed

    Ramírez, Carlos; León, Noel; García, Héctor; Aguayo, Humberto

    2015-06-01

    Solar tracking concentrators are optical systems that collect the solar energy flux either in a line or spot using reflective or refractive surfaces. The main problem with these surfaces is their manufacturing complexity, especially at large scales. In this paper, a line-to-spot solar tracking concentrator is proposed. Its configuration allows for a low-cost solar concentrator system. It consists of a parabolic trough collector (PTC) and a two-section PMMA Fresnel lens (FL), both mounted on a two-axis solar tracker. The function of the PTC is to reflect the incoming solar radiation toward a line. Then, the FL, which is placed near the focus, transforms this line into a spot by refraction. It was found that the system can achieve a concentration ratio of 100x and concentrate an average solar irradiance of 518.857W/m2 with an average transmittance of 0.855, taking into account the effect of the chromatic aberration.

  18. 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.

  19. 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.

  20. Parabolic flight experiments on physiological data acquisition and processing technologies using small jet aircraft (MU300).

    PubMed

    Watanabe, S; Nagaoka, S; Usui, S; Miyamoto, A; Suzuki, H; Hirata, T; Yoshimoto, S; Ueno, T; Kojima, T; Yamagata, M; Ishikura, S

    1994-05-01

    The parabolic aircraft flight provides a short low gravity environment for approximately 20 seconds, which may not be sufficient for a research on the physiological phenomenon induced by actual weightlessness in space. However, the method is still useful to reveal essential and characteristic feature of physiological signs, and is available for testing hardware and also training of crew member during altered gravity. This paper reports the summary of parabolic flight experiments recently conducted as a NASDA program (1990-1992). The program is providing opportunities in low gravity research with small jet aircraft for researchers and agencies. The flight experiments in the life science area have been conducted mostly focused on a physiological changes and basic methodology which may be effective under the altered gravity condition. In this study, the following research team, NASDA, Research Institute of Environmental Medicine, Nagoya University, Toyohashi University of Technology, Tokyo Metropolitan Hospital, Torey Research Center and JSUP were involved and coordinated for the research.

  1. Performance evaluation and simulation of a Compound Parabolic Concentrator (CPC) trough Solar Thermal Power Plant in Puerto Rico under solar transient conditions

    NASA Astrophysics Data System (ADS)

    Feliciano-Cruz, Luisa I.

    The increasing fossil fuel costs as well as the need to move in a somewhat sustainable future has led the world in a quest for exploiting the free and naturally available energy from the Sun to produce electric power, and Puerto Rico is no exception. This thesis proposes the design of a simulation model for the analysis and performance evaluation of a Solar Thermal Power Plant in Puerto Rico and suggests the use of the Compound Parabolic Concentrator as the solar collector of choice. Optical and thermal analysis of such collectors will be made using local solar radiation data for determining the viability of this proposed project in terms of the electric power produced and its cost.

  2. 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.

  3. 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.

  4. Sensitivity of Concentrating Solar Power Trough Performance, Cost and Financing with Solar Advisor Model

    SciTech Connect

    Blair, N.; Mehos, M.; Christensen, C.

    2008-03-01

    A comprehensive solar technology systems analysis model, the Solar Advisor Model (SAM) was developed to support the federal R&D community and the solar industry. This model, developed by staff at NREL and Sandia National Laboratory, is able to model the costs, finances, and performance of concentrating solar power and photovoltaics (PV). Currently, parabolic troughs and concentrating PV are the two concentrating technologies modeled within the SAM environment.

  5. Solar photovoltaic reflective trough collection structure

    DOEpatents

    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.

  6. 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.

  7. State-of-the-Art Review of Low-Cost Collector Technologies

    DTIC Science & Technology

    1981-06-01

    Mobility Low-Cost Parabolic Trough Survivability Light-Weight Thin-Film Reliability Heliostats Polymers Military 20. ABSTRACT (Contine an revers. deo It... heliostats and parabolic dish collectors. In addition several criteria were evaluated with respect to low-cost collector technologies These included...has produced collectors which incorporate sophisticated materials, = Heliostat heavy components, expensive seals and compli- o- (Point Focus) cated

  8. 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.

  9. 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.

  10. OUT Success Stories: Solar Trough Power Plants

    SciTech Connect

    Jones, J.

    2000-08-05

    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.

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

    NASA Astrophysics Data System (ADS)

    Tolbert, W. A.

    1981-06-01

    A brief but concise review is provided of low-cost solar collector technologies and their potential for application within the military. Low-cost, light-weight concepts for flat-plate collectors, parabolic trough collectors, heliostats and parabolic dish collectors are covered. In addition, several criteria are evaluated with respect to low-cost collector technologies. These include reliability, maintainability, survivability, motility/erectibility, environmental impact and economics. Research and development requirements and ongoing activities are also summarized.

  12. 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.

  13. 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.

  14. The Tippy Trough

    ERIC Educational Resources Information Center

    Young, Donald Francis

    2006-01-01

    Consider a trough with a uniform cross section that is bounded by different functions on its two sides, and assume that the trough can be tipped either way. The question explored is this: If the trough is partially filled with water, what angle of tipping will maximize the depth of the water?

  15. The planar parabolic optical antenna.

    PubMed

    Schoen, David T; Coenen, Toon; García de Abajo, F Javier; Brongersma, Mark L; Polman, Albert

    2013-01-09

    One of the simplest and most common structures used for directing light in macroscale applications is the parabolic reflector. Parabolic reflectors are ubiquitous in many technologies, from satellite dishes to hand-held flashlights. Today, there is a growing interest in the use of ultracompact metallic structures for manipulating light on the wavelength scale. Significant progress has been made in scaling radiowave antennas to the nanoscale for operation in the visible range, but similar scaling of parabolic reflectors employing ray-optics concepts has not yet been accomplished because of the difficulty in fabricating nanoscale three-dimensional surfaces. Here, we demonstrate that plasmon physics can be employed to realize a resonant elliptical cavity functioning as an essentially planar nanometallic structure that serves as a broadband unidirectional parabolic antenna at optical frequencies.

  16. Testing the figure of parabolic reflectors for solar concentrators.

    PubMed

    Bodenheimer, J S; Eisenberg, N P; Gur, J

    1982-12-15

    A novel method for testing the optical quality of large parabolic solar concentrators is presented, based on autocollimation. An optical system continuously scans the reflector along a fixed reference axis. At each position along the axis, the spread function is obtained. Analysis of the location, width, and intensity changes of this function gives quantitative information about the reflector's defects. A figure of merit describing the performance of parabolic trough reflectors is proposed.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Modeling Photovoltaic and Concentrating Solar Power Trough Performance, Cost, and Financing with the Solar Advisor Model: Preprint

    SciTech Connect

    Blair, N.; Mehos, M.; Christensen, C.; Cameron, C.

    2008-05-01

    A comprehensive solar technology systems analysis model, the Solar Advisor Model (SAM), has been developed to support the federal R&D community and the solar industry by staff at the National Renewable Energy Laboratory (NREL) and Sandia National Laboratory. This model is able to model the finances, incentives, and performance of flat-plate photovoltaic (PV), concentrating PV, and concentrating solar power (specifically, parabolic troughs). The primary function of the model is to allow users to investigate the impact of variations in performance, cost, and financial parameters to better understand their impact on key figures of merit. Figures of merit related to the cost and performance of these systems include, but aren't limited to, system output, system efficiencies, levelized cost of energy, return on investment, and system capital and O&M costs. There are several models within SAM to model the performance of photovoltaic modules and inverters. This paper presents an overview of each PV and inverter model, introduces a new generic model, and briefly discusses the concentrating solar power (CSP) parabolic trough model. A comparison of results using the different PV and inverter models is also presented.

  4. Development and Testing of a Power Trough System Using a Structurally-Efficient, High-Performance, Large-Aperture Concentrator with Thin Glass Reflector and Focal Point Rotation

    SciTech Connect

    May, E. K.; Forristall, R.

    2005-11-01

    Industrial Solar Technology has assembled a team of experts to develop a large-aperture parabolic trough for the electric power market that moves beyond cost and operating limitations of 1980's designs based on sagged glass reflectors. IST's structurally efficient space frame design will require nearly 50% less material per square meter than a Solel LS-2 concentrator and the new trough will rotate around the focal point. This feature eliminates flexhoses that increase pump power, installation and maintenance costs. IST aims to deliver a concentrator module costing less than $100 per square meter that can produce temperatures up to 400 C. The IST concentrator is ideally suited for application of front surface film reflectors and ensures that US corporations will manufacture major components, except for the high temperature receivers.

  5. Cut By Troughs

    NASA Technical Reports Server (NTRS)

    2005-01-01

    1 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an impact crater cut by troughs which formed after the crater formed. The crater and troughs have large windblown ripples on their floors. The ripples, troughs, craters, and other surfaces in this scene have all been mantled by dust. Dark streaks on slopes indicate areas where avalanches of dry dust have occurred. These features are located on Sacra Mena, a large mesa in the Kasei Valles region.

    Location near: 25.4oN, 66.8oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Autumn

  6. Modeling Photovoltaic and Concentrating Solar Power Trough Performance, Cost, and Financing with Solar Advisor Model

    SciTech Connect

    Blair, N.; Mehos, M.; Christensen, C.; Cameron, C.

    2008-01-01

    A comprehensive solar technology systems analysis model, the Solar Advisor Model (SAM), has been developed to support the federal R&D community and the solar industry by staff at the National Renewable Energy Laboratory (NREL) and Sandia National Laboratory. This model is able to model the finances, incentives, and performance of flat-plate photovoltaic (PV), concentrating PV, and concentrating solar power (specifically, parabolic troughs). The primary function of the model is to allow users to investigate the impact of variations in performance, cost, and financial parameters to better understand their impact on key figures of merit. Figures of merit related to the cost and performance of these systems include, but aren't limited to, system output, system efficiencies, levelized cost of energy, return on investment, and system capital and O&M costs. SAM allows users to do complex system modeling with an intuitive graphical user interface (GUI). In fact, all tables and graphics for this paper are taken directly from the model GUI. This model has the capability to compare different solar technologies within the same interface, making use of similar cost and finance assumptions. Additionally, the ability to do parametric and sensitivity analysis is central to this model. There are several models within SAM to model the performance of photovoltaic modules and inverters. This paper presents an overview of each PV and inverter model, introduces a new generic model, and briefly discusses the concentrating solar power (CSP) parabolic trough model. A comparison of results using the different PV and inverter models is also presented.

  7. 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)

  8. 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.

  9. 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.

  10. Analysis and conceptual design of a lunar radiator parabolic shade

    NASA Technical Reports Server (NTRS)

    Ewert, Michael K.; Clark, Craig S.

    1991-01-01

    On the moon, the available heat sink temperature for a vertical unshaded radiator at the equator is 322 K. A method of reducing this heat sink temperature using a parabolic trough shading device was investigated. A steady state heat balance was performed to predict the available heat sink temperature. The effect of optical surface properties on system performance was investigated. Various geometric configurations were also evaluated. A flexible shade conceptual design is presented which greatly reduces the weight and stowed volume of the system. The concept makes use of the natural catenary shape assumed by a flexible material when supported at two points. The catenary shape is very near parabolic. The lunar radiator parabolic shade design presented integrates the energy collection and rejection of a solar dynamic power cycle with the moderate temperature waste heat rejection of a lunar habitat.

  11. Analysis and conceptual design of a lunar radiator parabolic shade

    NASA Astrophysics Data System (ADS)

    Ewert, Michael K.; Clark, Craig S.

    On the moon, the available heat sink temperature for a vertical unshaded radiator at the equator is 322 K. A method of reducing this heat sink temperature using a parabolic trough shading device was investigated. A steady state heat balance was performed to predict the available heat sink temperature. The effect of optical surface properties on system performance was investigated. Various geometric configurations were also evaluated. A flexible shade conceptual design is presented which greatly reduces the weight and stowed volume of the system. The concept makes use of the natural catenary shape assumed by a flexible material when supported at two points. The catenary shape is very near parabolic. The lunar radiator parabolic shade design presented integrates the energy collection and rejection of a solar dynamic power cycle with the moderate temperature waste heat rejection of a lunar habitat.

  12. 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.

  13. Sirenum Fossae Trough

    NASA Technical Reports Server (NTRS)

    2000-01-01

    [figure removed for brevity, see original site]

    The Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) orbits the red planet twelve times each day. The number of pictures that MOC can take varies from orbit to orbit, depending upon whether the data are being stored in MGS's onboard tape recorder for playback at a later time, or whether the data are being sent directly back to Earth via a real-time radio link. More data can be acquired during orbits with real-time downlink.

    During real-time orbits, the MOC team often will take a few random or semi-random pictures in between the carefully-selected, hand-targeted images. On rare occasions, one of these random pictures will surprise the MOC team. The picture shown here is an excellent example, because the high resolution view (top) is centered so nicely on a trough and an adjacent, shallow crater that it is as if someone very carefully selected the target for MOC. The high-resolution view covers an area only 1.1 km (0.7 mi) wide by 2.3 km (1.4 mi) long. Hitting a target such as this with such a small image is very difficult to do, on purpose, because there are small uncertainties in the predicted orbit, the maps used to select targets, and the minor adjustments of spacecraft pointing at any given moment. Nevertheless, a very impressive image was received.

    The high resolution view crosses one of the troughs of the Sirenum Fossae near 31.2oS, 152.3oW. The context image (above) was acquired at the same time as the high resolution view on July 23, 2000. The small white box shows the location of the high resolution picture. The lines running diagonally across the context image from upper right toward lower left are the Sirenum Fossae troughs, formed by faults that are radial to the volcanic region of Tharsis. Both pictures are illuminated from the upper left. The scene shows part of the martian southern hemisphere nearly autumn.

  14. 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.

  15. Parabolically connected subgroups

    SciTech Connect

    Netai, Igor V

    2011-08-31

    All reductive spherical subgroups of the group SL(n) are found for which the intersections with every parabolic subgroup of SL(n) are connected. This condition guarantees that open equivariant embeddings of the corresponding homogeneous spaces into Moishezon spaces are algebraic. Bibliography: 6 titles.

  16. 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.

  17. 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.

  18. Parabolic solar systems

    NASA Astrophysics Data System (ADS)

    Parsons, W. L., IV; Goetchius, W.

    The further development of parabolic solar collectors to increase their efficiency and simplify their operation was the prime objective of this research project. Three primary objectives were pursued. The first of these was to investigate the simplest and most efficient techniques to build and mass-produce parabolic solar collectors. The second objective was to further develop and simplify absorber tubes used to collect and transfer the solar energy. Absorber tubes represented a significant area of this research project. The third objective was to develop accurate, low cost, and durable tracking systems for solar collectors. Solar tracking systems are covered including several schematic representations of various systems and designs. The testing systems and associated mechanisms for the designs discussed in this report are described.

  19. On maximal parabolic regularity for non-autonomous parabolic operators

    NASA Astrophysics Data System (ADS)

    Disser, Karoline; ter Elst, A. F. M.; Rehberg, Joachim

    2017-02-01

    We consider linear inhomogeneous non-autonomous parabolic problems associated to sesquilinear forms, with discontinuous dependence of time. We show that for these problems, the property of maximal parabolic regularity can be extrapolated to time integrability exponents r ≠ 2. This allows us to prove maximal parabolic Lr-regularity for discontinuous non-autonomous second-order divergence form operators in very general geometric settings and to prove existence results for related quasilinear equations.

  20. 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.

  1. Freeze-thaw tests of trough receivers employing a molten salt working fluid.

    SciTech Connect

    Moss, Timothy A.; Iverson, Brian D.; Siegel, Nathan Phillip; Kolb, Gregory J.; Ho, Clifford Kuofei

    2010-05-01

    Several studies predict an economic benefit of using nitrate-based salts instead of the current synthetic oil within a solar parabolic trough field. However, the expected economic benefit can only be realized if the reliability and optical performance of the salt trough system is comparable to today's oil trough. Of primary concern is whether a salt-freeze accident and subsequent thaw will lead to damage of the heat collection elements (HCEs). This topic was investigated by experiments and analytical analysis. Results to date suggest that damage will not occur if the HCEs are not completely filled with salt. However, if the HCE is completely filled at the time of the freeze, the subsequent thaw can lead to plastic deformation and significant bending of the absorber tube.

  2. 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

  3. Mechatronic Prototype of Parabolic Solar Tracker.

    PubMed

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

    2016-06-15

    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.

  4. 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

  5. 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.

  6. 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

  7. First Middle East Aircraft Parabolic Flights for ISU Participant Experiments

    NASA Astrophysics Data System (ADS)

    Pletser, Vladimir; Frischauf, Norbert; Cohen, Dan; Foster, Matthew; Spannagel, Ruven; Szeszko, Adam; Laufer, Rene

    2017-02-01

    Aircraft parabolic flights are widely used throughout the world to create microgravity environment for scientific and technology research, experiment rehearsal for space missions, and for astronaut training before space flights. As part of the Space Studies Program 2016 of the International Space University summer session at the Technion - Israel Institute of Technology, Haifa, Israel, a series of aircraft parabolic flights were organized with a glider in support of departmental activities on `Artificial and Micro-gravity' within the Space Sciences Department. Five flights were organized with manoeuvres including several parabolas with 5 to 6 s of weightlessness, bank turns with acceleration up to 2 g and disorientation inducing manoeuvres. Four demonstration experiments and two experiments proposed by SSP16 participants were performed during the flights by on board operators. This paper reports on the microgravity experiments conducted during these parabolic flights, the first conducted in the Middle East for science and pedagogical experiments.

  8. 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.

  9. 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.

  10. Solar thermal technology

    NASA Astrophysics Data System (ADS)

    1986-08-01

    This annual evaluation report provides the accomplishments and progress of government-funded activities initiated, renewed, or completed during Fiscal Year 1985 (October 1, 1984 through September 30, 1985). It highlights the program tasks conducted by participating national laboratories and by contracting industrial academic, or other research institutions. The focus of the STT Program is research and development leading to the commercial readiness of four primary solar thermal concepts: (1) central receiver; (2) parabolic dish; (3) parabolic trough; and (4) hemispherical bowl.

  11. 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.

  12. 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…

  13. 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.

  14. 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.

  15. 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.

  16. Tectonic evolution of the northernmost Okinawa Trough

    NASA Astrophysics Data System (ADS)

    Oiwane, H.; Tonai, S.; Nakamura, Y.; Kiyokawa, S.; Tokuyama, H.

    2007-12-01

    Over the last decades, mechanism of backarc opening has been the subject of controversy. Okinawa Trough has been noticed as an incipient continental backarc basin. So far studies on the Okinawa Trough have been conducted mainly in its southern and middle part. Nevertheless, only a few studies have been conducted on the relationship between geologic structures and the tectonic evolution of northernmost Okinawa Trough. Our main object is to consider the tectonic evolution of the Okinawa Trough by means of structural geology, not only in ocean but also land area. We executed seismic reflection survey in northernmost Okinawa trough and investigated fault systems on Koshikijima islands located on northeastern edge of the Okinawa Trough. Then we compared geologic structures on land and sea floor. First of all, we interpreted seismic reflection data acquired by hydraulic department of Japan Coast Guard in northernmost Okinawa Trough in 1975. Furthermore, we executed multi-channel seismic reflection survey in this area (KT06-03, KT07-03 cruise). NNE and ENE trending fault systems were recognized. It is clear that Northernmost Okinawa Trough has been subsided by activation of NNE trending fault system at the east edge of trough basin with several hundred meters of displacement. The ENE trending fault system has displacement in the surface sediment, which means they are active faults. On the other hand, we held on-land field survey in northern part of the Koshikijima Islands. Fault system, which can be related to the Okinawa Trough, is reported in this area (Inoue et al., 1982). So we focused on that NNE trending normal fault system (F2 fault system). On the basis of crosscut relationship and K-Ar dating of fault rocks and dikes, F2 fault system was formed after late Miocene and likely to have been formed in a shallow underground. F2 fault system on Koshikijima islands and NNE trending fault systems in the Okinawa Trough have similar strike, displaced direction and

  17. 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.

  18. From parabolic-trough to metasurface-concentrator: assessing focusing in the wave-optics limit.

    PubMed

    Hsu, Liyi; Dupré, Matthieu; Ndao, Abdoulaye; Kanté, Boubacar

    2017-04-15

    Metasurfaces are promising tools toward novel designs for flat optics applications. As such, their quality and tolerance to fabrication imperfections need to be evaluated with specific tools. However, most such tools rely on the geometrical optics approximation and are not straightforwardly applicable to metasurfaces. In this Letter, we introduce and evaluate for metasurfaces parameters such as intercept factor and slope error usually defined for solar concentrators in the realm of ray-optics. After proposing definitions valid in physical optics, we put forward an approach to calculate them. As examples, we design three different concentrators based on three specific unit cells and assess them numerically. The concept allows for comparison of the efficiency of the metasurfaces and their sensitivities to fabrication imperfections and will be critical for practical systems implementation.

  19. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1983-02-01

    A simplified theory for the bending behavior of a thin flat bilamina panel was 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.

  1. Comparison of performance of flat plate and parabolic trough solar collectors in several US cities

    SciTech Connect

    Stromberg, R.P.; Bush, L.D.

    1981-01-01

    One very common use of the flat plate collector is residential water heating. Concentrating thermal collectors have been developed for much higher temperature uses, based on the knowledge that the upper limit on output from the flat plate collector is roughly at the boiling point of water. Total annual outputs are extensively compared. There is a significant variation in relative performance of flat plate and concentrating collectors in different climates. There is a noticeable variation in relative output from winter to summer. In some parts of the United States the weather conditions of winter favor the use of concentrating collectors over flat plate collectors for residential water heating.

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

    NASA Astrophysics Data System (ADS)

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

    1981-06-01

    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.

  3. 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.

  4. 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.

  5. Low Sidelobe Scanning Beams for Parabolic Reflectors,

    DTIC Science & Technology

    Parabolic antennas, *Sidelobes, *Electronic scanners, Parabolas, Far field, Antenna feeds , Reflectors, Low level, Amplitude, Distortion, Configurations, Secondary, Compensation, Feeding , Symposia, Taper

  6. Climatology of the winter Red Sea Trough

    NASA Astrophysics Data System (ADS)

    Awad, Adel M.; Almazroui, Mansour

    2016-12-01

    In this study, a new and objective method for detecting the Red Sea Trough (RST) was developed using mean sea level pressure (SLP) data from NCEP/NCAR reanalysis dataset from the winters of 1956 to 2015 to identify the Sudan Low and its trough. Approximately 96% of the winter RSTs were generated near two main sources, South Sudan and southeastern Sudan, and approximately 85% of these troughs were in four of the most outer areas surrounding the northern Red Sea. Moreover, from west to east of the Red Sea, the RST was affected by the relationships between the Siberian High and Azores High. The RST was oriented to the west when the strength of the Siberian High increased and to the east when the strength of the Azores High increased. Furthermore, the synoptic features of the upper level of the RST emphasize the impacts of subtropical anticyclones at 850 hPa on the orientation of the RST, the impacts of the northern cyclone trough and the maximum wind at a pressure level of 250 hPa. The average static stability between 1000 hPa and 500 hPa demonstrated that the RST followed the northern areas of low static stability. The results from previous studies were confirmed by a detailed case study of the RST that extended to its central outermost area. The results of a detailed case study of the short RST indicated that the trough becomes shorter with increasing static stability and that the Azores and Siberian high-pressure systems influence the northern region of the trough while the maximum upper wind shifts south of the climate position.

  7. Existence results for quasilinear parabolic hemivariational inequalities

    NASA Astrophysics Data System (ADS)

    Liu, Zhenhai

    This paper is devoted to the periodic problem for quasilinear parabolic hemivariational inequalities at resonance as well as at nonresonance. By use of the theory of multi-valued pseudomonotone operators, the notion of generalized gradient of Clarke and the property of the first eigenfunction, we build a Landesman-Lazer theory in the nonsmooth framework of quasilinear parabolic hemivariational inequalities.

  8. Parabolic Herz Spaces and their Applications

    NASA Astrophysics Data System (ADS)

    Ragusa, Maria Alessandra

    2010-09-01

    The note is a natural continuations of the study started in [7]. In Herz spaces endowed with parabolic metric are proved regularity results of weak solutions to divergence form parabolic equations having discontinuous coefficients, using boundedness of integral operators and commutators generated by VMO functions and Calderón-Zygmund operators.

  9. 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.

  10. Macrobenthos of the Novaya Zemlya Trough

    NASA Astrophysics Data System (ADS)

    Galkin, S. V.; Savilova, T. A.; Moskalev, L. I.; Kucheruk, N. V.

    2010-12-01

    During the 54th cruise of the R/V Akademik Mstislav Keldysh the macrobenthos of the Novaya Zemlya Trough was studied using a Sigsby trawl along the submeridional transect near 75°30'N latitude at a depth range from 68 to 362 m. In total, 140 species of bottom animals were found. The relative role of the taxons was assessed using three indices: the number, biomass, and energy flow. Similarity indices were used for the comparison of the samples. The new material greatly contributes to the data on the composition of the fauna and the structure of the communities of the studied region. It was revealed that small scyphozoid polyps and sipunculoids play an important role in the trough's community. The presence of the community dominated by Ophiocten sericeum (with the important role of small bivalves) was revealed for the first time not only at the eastern by also at the western slope of the Novaya Zemlya Trough. The sharpest changes in the composition and structure of the bottom community were confined to the zone of the transition from the trough floor to the slope. These changes are determined by the specificity of the macrorelief (of the floor and slope), the composition of the ground (soft brown silts abound in rhizopods and dense gray silts with an admixture of pebbles), and possibly by the hydrodynamic processes near the bottom.

  11. Crustal structure of the Mariana Trough

    SciTech Connect

    Ambos, E.L.; Hussong, D.M.

    1982-05-10

    Three seismic refraction profiles were shot in the Mariana Trough in the vicinity of the proposed axial rift spreading center. One long east-west trending line was shot across the axial high region, the elevated portion of the trough associated with the rift zone. The two other lines were shot in a rough north-south orientation subparallel to the trend of the axial rift, on crusts 1 and 5--6 m.y. old. Comparison of the results of the ray-tracing analysis for these two profiles indicated that thinning of layer 2A (velocity of 3.3 km/s) and development of a distinct layer 2B (velocity of 5.3 km/s and development of a distinct layer 2B (velocity of 5.3 km/s) and layer 3A (velocity of 6.7 km/s) takes place with increasing crustal age, implying a process of crustal evolution. The presence of large-scale crustal faults was noted in several instances. In addition, a consistent but low upper mantle seismic velocity of 7.7 km/s was measured for all three lines. These characteristics correlate with those previously observed for other areas of young oceanic crust. When compared with major active spreading centers such as the Mid-Atlantic Ridge and East Pacific Rise, the Mariana Trough appears similar to the former in most respects. Both the Mid-Atlantic Ridge and Mariana Trough are slow spreading (1-2 cm/yr half rate) and are characterized by rough topography, an axial rift, and a thick layer/sup 2/. Like the Mid-Atlantic Ridge, the Mariana Trough also has no low-velocity zone in the crust that could be interpreted as a magma chamber at the spreading center.

  12. Acoustic Impact of Short-Term Ocean Variability in the Okinawa Trough

    DTIC Science & Technology

    2010-01-20

    Florida State University Tallahassee, FL USA P. Spence QinetiQ North America Technology Solutions Group —PSI, Stennis Space Center, MS, USA...analyses and public observations in the Okinawa Trough region over I August - 31 October 2007. MLD(m) ILD(m) SLD (m) BLG ((m/s)/100m) RMS BIAS RMS BIAS RMS

  13. Photovoltaic applications of Compound Parabolic Concentrator (CPC)

    NASA Technical Reports Server (NTRS)

    Winston, R.

    1975-01-01

    The use of a compound parabolic concentrator as field collector, in conjunction with a primary focusing concentrator for photovoltaic applications is studied. The primary focusing concentrator can be a parabolic reflector, an array of Fresnel mirrors, a Fresnel lens or some other lens. Silicon solar cell grid structures are proposed that increase efficiency with concentration up to 10 suns. A ray tracing program has been developed to determine energy distribution at the exit of a compound parabolic concentrator. Projected total cost of a CPC/solar cell system will be between 4 and 5 times lower than for flat plate silicon cell arrays.

  14. 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.

  15. THz Radiation Source Trough Periodically Modulated Structures

    DTIC Science & Technology

    1997-12-04

    Trough Periodically Modulated Structures C 6. AUTHOR(S) N 68171-96-C-9015 E. Gornik, Ch. Rauch, G. Strasser, K. Unterrainer, R. Kersting 7...is used to ,ad M6 probe the transmittance of undoped GaAs/Ga0.7A10 3As superlattices. The measured ofninjecte elnjectron collector current reflects...period superlattice is shown for different collector biases. The black solid line represents the transfer ratio at flat band condition (UBc=0). A clear

  16. Flow dynamics in a trough blowout

    NASA Astrophysics Data System (ADS)

    Hesp, Patrick A.

    1996-02-01

    The dynamics and geomorphological development of a trough blowout located at Fiona Beach in the Myall Lakes National Park in NSW, Australia are examined. Wind velocities and flow structure were measured utilising an array of miniature Rimco cup anemometers, Gill bi-vane and UVW instruments, and wind vanes. Flow measurements indicate that when the wind approaches the trough blowout parallel to the throat orientation, jets occur both in the deflation basin and along the erosional walls, relative flow deceleration and expansion occur up the depositional lobe, jets are formed over the depositional lobe crest accompanied by downwind flow separation on the leeward side of the lobe, and flow separation and the formation of corkscrew vortices occur over the crests of the erosional walls. Maximum erosion and transport occur up the deflation basin and onto the depositional lobe. Trough blowout morphologies are explained as a function of these flow patterns. When the wind approaches the blowout obliquely, the flow is steered considerably within the blowout. The degree and complexity of topographic steering is dependent on the blowout topography. The flow is usually extremely turbulent and large corkscrew vortices are common. The local topography of a blowout can be very important in determining flow patterns, overall sand transport and blowout evolutionary conditions and paths. Estimates of potential sand transport within the blowout may be up to two orders of magnitude lower than actual rates if remote wind data are used.

  17. Lipoxygenase activity during parabolic flights.

    PubMed

    Maccarrone, M; Tacconi, M; Battista, N; Valgattarri, F; Falciani, P; Finazzi-Agro, A

    2001-07-01

    Experiments in Space clearly show that various cellular processes, such as growth rates, signaling pathways and gene expression, are modified when cells are placed under conditions of weightlessness. As yet, there is no coherent explanation for these observations, though recent experiments, showing that microtubule self-organization is gravity-dependent suggest that investigations at the molecular level might fill the gap between observation and understanding of Space effects. Lipoxygenases are a family of dioxygenases which have been implicated in the pathogenesis of several inflammatory conditions, in atherosclerosis, in brain aging and in HIV infection. In plants, lipoxy-genases favour germination, participate in the synthesis of traumatin and jasmonic acid and in the response to abiotic stress. Here, we took advantage of a fibre optics spectrometer developed on purpose, the EMEC (Effect of Microgravity on Enzymatic Catalysis) module, to measure the dioxygenation reaction by pure soybean lipoxygenase-1 (LOX-1) during the 28th parabolic flight campaign of the European Space Agency (ESA). The aim was to ascertain whether microgravity can affect enzyme catalysis.

  18. 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.

  19. 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.

  20. Age and structure of the southern Rockall Trough: New evidence

    NASA Astrophysics Data System (ADS)

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

    1981-01-01

    The Rockall Trough separates the Rockall Plateau microcontinent from the shelf and slope west of the British Isles. The structure and age of the trough has been the source of considerable discussion. Although widely considered to be of oceanic origin, postulated ages for the spreading range from Permian to Cretaceous. New seismic profiles linked to the IPOD sites in the Bay of Biscay and to oceanic anomalies of known age are used to present a new assessment of the age and structure of the southern Rockall Trough. It is concluded that about 120 km of ocean crust is present in the trough and that spreading took place in the Albian-Maastrichtian interval.

  1. Beam diffraction by planar and parabolic reflectors

    NASA Astrophysics Data System (ADS)

    Suedan, Gibreel A.; Jull, Edward V.

    1991-04-01

    In the complex source point (CSP) technique, an omnidirectional source diffraction solution becomes that for a directive beam when the coordinates of the source position are given appropriate complex values. This is applied to include feed directivity in reflector edge diffraction. Solutions and numerical examples for planar strip and parabolic cylinder reflectors are given, including an offset parabolic reflector. The main beams of parabolic reflectors are calculated by aperture integration and the edge diffracted fields by uniform diffraction theory. In both cases, a complex source point feed in the near or far field of the reflector may be used in the pattern calculation, with improvements in accuracy in the lateral and spillover pattern lobes.

  2. Parabolic Ejecta Features on Titan? Probably Not

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.; Melosh, H. J.

    1996-03-01

    Radar mapping of Venus by Magellan indicated a number of dark parabolic features, associated with impact craters. A suggested mechanism for generating such features is that ejecta from the impact event is 'winnowed' by the zonal wind field, with smaller ejecta particles falling out of the atmosphere more slowly, and hence drifting further. What discriminates such features from simple wind streaks is the 'stingray' or parabolic shape. This is due to the ejecta's spatial distribution prior to being winnowed during fallout, and this distribution is generated by the explosion plume of the impact piercing the atmosphere, allowing the ejecta to disperse pseudoballistically before re-entering the atmosphere, decelerating to terminal velocity and then being winnowed. Here we apply this model to Titan, which has a zonal wind field similar to that of Venus. We find that Cassini will probably not find parabolic features, as the winds stretch the deposition so far that ejecta will form streaks or bands instead.

  3. Controllable parabolic-cylinder optical rogue wave.

    PubMed

    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.

  4. 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

  5. Postmidnight ionospheric troughs in summer at high latitudes

    NASA Astrophysics Data System (ADS)

    Voiculescu, M.; Nygrén, T.; Aikio, A. T.; Vanhamäki, H.; Pierrard, V.

    2016-12-01

    In this article we identify possible mechanisms for the formation of postmidnight ionospheric troughs during summer, in sunlit plasma. Four events were identified in measurements of European Incoherent Scatter and ESR radars during CP3 experiments, when the ionosphere was scanned in a meridional plan. The spatial and temporal variation of plasma density, ion, and electron temperatures were analyzed for each of the four events. Super Dual Auroral Radar Network plasma velocity measurements were added, when these were available. For all high-latitude troughs the ion temperatures are high at density minima (within the trough), at places where the convection plasma velocity is eastward and high. There is no significant change in electron temperature inside the trough, regardless of its temporal evolution. We find that troughs in sunlit plasma form in two steps: the trough starts to form when energetic electron precipitation leads to faster recombination in the F region, and it deepens when entering a region with high eastward flow, producing frictional heating and further depleting the plasma. The high-latitude plasma convection plays an important role in formation and evolution of troughs in the postmidnight sector in sunlit plasma. During one event a second trough is identified at midlatitudes, with different characteristics, which is most likely produced by a rapid subauroral ion drift in the premidnight sector.

  6. 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

  7. 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.

  8. Use of water troughs by badgers and cattle.

    PubMed

    O'Mahony, D T

    2014-12-01

    The frequency of visits by badgers and cattle to five water troughs was examined using motion-activated infra-red cameras in a farming landscape in Northern Ireland between May and July 2013. Cattle visit rates varied significantly across troughs, were greatest during daylight periods, and more frequent during dry weather. Badgers were recorded visiting only one of the five water troughs. These visits were recorded on 14 different nights between midnight and 0300 h and were mainly by individual badgers. Water troughs were not used concurrently by badgers and cattle and the minimum period between badger and cattle use was 3 days. Although badgers used water troughs rarely during the study there remains the potential for indirect transmission of a bacterium such as Mycobacterium bovis that may merit further investigation.

  9. Are Vancomycin Trough Concentrations Adequate for Optimal Dosing?

    PubMed Central

    Youn, Gilmer; Jones, Brenda; Jelliffe, Roger W.; Drusano, George L.; Rodvold, Keith A.; Lodise, Thomas P.

    2014-01-01

    The current vancomycin therapeutic guidelines recommend the use of only trough concentrations to manage the dosing of adults with Staphylococcus aureus infections. Both vancomycin efficacy and toxicity are likely to be related to the area under the plasma concentration-time curve (AUC). We assembled richly sampled vancomycin pharmacokinetic data from three studies comprising 47 adults with various levels of renal function. With Pmetrics, the nonparametric population modeling package for R, we compared AUCs estimated from models derived from trough-only and peak-trough depleted versions of the full data set and characterized the relationship between the vancomycin trough concentration and AUC. The trough-only and peak-trough depleted data sets underestimated the true AUCs compared to the full model by a mean (95% confidence interval) of 23% (11 to 33%; P = 0.0001) and 14% (7 to 19%; P < 0.0001), respectively. In contrast, using the full model as a Bayesian prior with trough-only data allowed 97% (93 to 102%; P = 0.23) accurate AUC estimation. On the basis of 5,000 profiles simulated from the full model, among adults with normal renal function and a therapeutic AUC of ≥400 mg · h/liter for an organism for which the vancomycin MIC is 1 mg/liter, approximately 60% are expected to have a trough concentration below the suggested minimum target of 15 mg/liter for serious infections, which could result in needlessly increased doses and a risk of toxicity. Our data indicate that adjustment of vancomycin doses on the basis of trough concentrations without a Bayesian tool results in poor achievement of maximally safe and effective drug exposures in plasma and that many adults can have an adequate vancomycin AUC with a trough concentration of <15 mg/liter. PMID:24165176

  10. Side-by-side comparisons of evacuated compound parabolic concentrator and flat plate solar collector systems

    SciTech Connect

    McGarity, A.E.; Allen, J.W.; Schertz, W.W.

    1983-10-01

    Three liquid-based solar heating systems employing different types of solar collectors were tested side by side near Chicago, Illinois for one year. The three different types of collectors were: a flat plate collector with a black-chrome coated absorber plate and one low-iron glass cover; an evacuated-tube compound parabolic concentrator (CPC) with a concentration ratio of 1.1, oriented with tubes and troughs along a north-south axis; and an evacuated-tube CPC collector with a concentration ratio of 1.3 and one low-iron glass cover, with tubes and troughs oriented along an east-west axis. Results indicate that the flat plate collector system was the most efficient during warm weather, but the CPC systems were more efficient during cold weather, but the CPC systems were more efficient during cold weather, and the CPC systems operated under conditions too adverse for the flat plate collector. The computer simulation model ANSIM was validated by means of the side-by-side tests. The model uses analytical solutions to the storage energy balance. ANSIM is compared with the general simulation TRNSYS. (LEW)

  11. Elevated Vancomycin Trough Concentration: Increased Efficacy and/or Toxicity?

    PubMed Central

    Elyasi, Sepideh; Khalili, Hossein; Dashti-Khavidaki, Simin; Emadi-Koochak, Hamid; Mohammadpour, Amirhooshang; Abdollahi, Alireza

    2014-01-01

    Vancomycin susceptibility of methicillin-resistant Staphylococcus aureus has been changed over time and its average minimum inhibitory concentration increased from 1.5 to 1.75 mg/L.A recently published guideline by the American Society of Health Pharmacist recommended a daily dose of 15-20 mg/Kg every 8 to 12 hours of vancomycin to achieve a trough concentration between 15-20 mg/L for treatment of severe infections. Medical records of 69 patients from infectious ward of Imam Khomeini hospital, with suspected or confirmed gram-positive infection who had at least one trough level of vancomycin, were evaluated regarding vancomycin therapeutic goal; efficacy and renal safety. Most of patients (60.6%) with severe infections did not achieve the recommended vancomycin trough level during treatment course. Time to normalization of the signs and symptoms of infection did not correlate with the patients’ serum vancomycin trough levels. At the end of treatment course, there was no significant correlation between patients’ creatinine clearance and vancomycin trough levels (P=0.32). However, patients’cratinine clearance showed a negatively significant correlation with trough level of vancomycin (P=0.01). Vancomycin induced nephrotoxicity was detected in 4.3% of the patients. These data showed that vancomycin trough level may not necessarily assure treatment success, and also it would not essentially predict the risk of vancomycin induced nephrotoxicity. However, more well designed studies with larger sample size needed for better clinical and practical judgment. PMID:25587313

  12. 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.

  13. Who dares to join a parabolic flight?

    NASA Astrophysics Data System (ADS)

    Montag, Christian; Zander, Tina; Schneider, Stefan

    2016-12-01

    Parabolic flights represent an important tool in space research to investigate zero gravity on airplanes. Research on these flights often target psychological and biological processes in humans to investigate if and how we can adapt to this unique environment. This research is costly, hard to conduct and clearly heavily relies on humans participating in experiments in this (unnatural) situation. The present study investigated N =66 participants and N =66 matched control persons to study if participants in such experimental flights differ in terms of their personality traits from non-parabonauts. The main finding of this study demonstrates that parabonauts score significantly lower on harm avoidance, a trait closely linked to being anxious. As anxious humans differ from non-anxious humans in their biology, the present observations need to be taken into account when aiming at the generalizability of psychobiological research findings conducted in zero gravity on parabolic flights.

  14. Parabolic dish collectors - A solar option

    NASA Astrophysics Data System (ADS)

    Truscello, V. C.

    1981-05-01

    A description is given of several parabolic-dish high temperature solar thermal systems currently undergoing performance trials. A single parabolic dish has the potential for generating 20 to 30 kW of electricity with fluid temperatures from 300 to 1650 C. Each dish is a complete power-producing unit, and may function either independently or as part of a group of linked modules. The two dish designs under consideration are of 11 and 12 meter diameters, yielding receiver operating temperatures of 925 and 815 C, respectively. The receiver designs described include (1) an organic working fluid (toluene) Rankine cycle engine; (2) a Brayton open cycle unit incorporating a hybrid combustion chamber and nozzle and a shaft-coupled permanent magnet alternator; and (3) a modified Stirling cycle device originally designed for automotive use. Also considered are thermal buffer energy storage and thermochemical transport and storage.

  15. Essential Parabolic Structures and Their Infinitesimal Automorphisms

    NASA Astrophysics Data System (ADS)

    Alt, Jesse

    2011-04-01

    Using the theory of Weyl structures, we give a natural generalization of the notion of essential conformal structures and conformal Killing fields to arbitrary parabolic geometries. We show that a parabolic structure is inessential whenever the automorphism group acts properly on the base space. As a corollary of the generalized Ferrand-Obata theorem proved by C. Frances, this proves a generalization of the ''Lichnérowicz conjecture'' for conformal Riemannian, strictly pseudo-convex CR, and quaternionic/octonionic contact manifolds in positive-definite signature. For an infinitesimal automorphism with a singularity, we give a generalization of the dictionary introduced by Frances for conformal Killing fields, which characterizes (local) essentiality via the so-called holonomy associated to a singularity of an infinitesimal automorphism.

  16. Parabolic cylinder functions of large order

    NASA Astrophysics Data System (ADS)

    Jones, D. S.

    2006-06-01

    The asymptotic behaviour of parabolic cylinder functions of large real order is considered. Various expansions in terms of elementary functions are derived. They hold uniformly for the variable in appropriate parts of the complex plane. Some of the expansions are doubly asymptotic with respect to the order and the complex variable which is an advantage for computational purposes. Error bounds are determined for the truncated versions of the asymptotic series.

  17. Improved Parabolization of the Euler Equations

    DTIC Science & Technology

    2013-05-01

    generalization of linear stability theory call the parabolized stability equations ( PSE ).10 PSE can partially capture nonparallel and nonlinear effects...and has been shown to accurately model many convectively unstable flows. In particular, our group has previously shown that linear PSE can produce...mode analysis. The efficiency of PSE is achieved by using a spatial marching technique in the streamwise direction. Initial conditions are specified

  18. The parabolic concentrating collector: A tutorial

    NASA Technical Reports Server (NTRS)

    Truscello, V. C.

    1979-01-01

    A tutorial overview of point-focusing parabolic collectors is presented. Optical and thermal characteristics are discussed. Data representing typical achievable collector efficiencies are presented and the importance of balancing collector cost with concentrator quality is argued through the development of a figure of merit. Various types of two-axis tracking collectors are described. The Department of Energy program to develop these devices is briefly discussed, as are present and projected costs for these collectors.

  19. 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.

  20. 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.

  1. Looking north inside of casthouse no. 6 at iron trough ...

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

    Looking north inside of casthouse no. 6 at iron trough and iron notch of blast furnace no. 6. - U.S. Steel Edgar Thomson Works, Blast Furnace Plant, Along Monongahela River, Braddock, Allegheny County, PA

  2. 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

  3. "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

  4. 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.

  5. The First European Parabolic Flight Campaign with the Airbus A310 ZERO-G

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    Aircraft parabolic flights repetitively provide up to 23 seconds 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 future Chinese Space Station. After 17 years of using the Airbus A300 ZERO-G, the French company Novespace, a subsidiary of the ' Centre National d'Etudes Spatiales' (CNES, French Space Agency), based in Bordeaux, France, purchased a new aircraft, an Airbus A310, to perform parabolic flights for microgravity research in Europe. Since April 2015, the European Space Agency (ESA), CNES and the ` Deutsches Zentrum für Luft- und Raumfahrt e.V.' (DLR, the German Aerospace Center) use this new aircraft, the Airbus A310 ZERO-G, for research experiments in microgravity. The first campaign was a Cooperative campaign shared by the three agencies, followed by respectively a CNES, an ESA and a DLR campaign. This paper presents the new Airbus A310 ZERO-G and its main characteristics and interfaces for scientific experiments. The experiments conducted during the first European campaign are presented.

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

    DOE PAGES

    Gruen, D.; Friedrich, O.; Amara, A.; ...

    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

  7. Basic geochemical characteristics of sediments in the Okinawa trough

    NASA Astrophysics Data System (ADS)

    Zhao, Yiyang; He, Lijuan; Zhang, Xiulian; Jia, Fengmei; Xia, Qing

    1986-09-01

    A total of 21 elements, Si, Al, K, Na, Ca, Mg, Fe, Mn, Ti, P, Cu, Co, Ni, Zn, Pb, Cr, Rb, Sr Ba, Cd and Corg(organic carbon), was determined in the trough. Average contents of most elements were found to be higher in the trough bottom than in the western and eastern slopes. We call these elements the indicator elements because of their “transition” property. This is in keeping with the “intermediate” geographical position of the trough where the continental crust turns to oceanic crust. Though the authigenic fraction of some elements here increases, the detrital fraction of most elements is still dominant, indicating that the influences of terrigenous and volcanic detrital materials on the trough sediments are still dominant. The abundant biogenous component in the trough is characterized by the increase of Ca, Sr, and Corg contents. Ca existes mainly in the form of CaCo3 that is mostly found in various shells. Sr often easily replaces Ca within the shells. A belt-shaped distribution pattern of elements was found in the south and a “block” pattern in the north trough. Such distribution patterns are directly controlled by water depth, topography, current sediment type, and mineral, biological, and volcanic processes.

  8. 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.

  9. 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.

  10. 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.

  11. Nonlinear Parabolic Equations Involving Measures as Initial Conditions.

    DTIC Science & Technology

    1981-09-01

    CHART N N N Afl4Uf’t 1N II Il MRC Technical Summary Report # 2277 0 NONLINEAR PARABOLIC EQUATIONS INVOLVING MEASURES AS INITIAL CONDITIONS I Haim Brezis ...NONLINEAR PARABOLIC EQUATIONS INVOLVING MEASURES AS INITIAL CONDITIONS Haim Brezis and Avner Friedman Technical Summary Report #2277 September 1981...with NRC, and not with the authors of this report. * 𔃾s ’a * ’ 4| NONLINEAR PARABOLIC EQUATIONS INVOLVING MEASURES AS INITIAL CONDITIONS Haim Brezis

  12. Bifurcation and stability for a nonlinear parabolic partial differential equation

    NASA Technical Reports Server (NTRS)

    Chafee, N.

    1973-01-01

    Theorems are developed to support bifurcation and stability of nonlinear parabolic partial differential equations in the solution of the asymptotic behavior of functions with certain specified properties.

  13. 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.

  14. A New Error Bound for Reduced Basis Approximation of Parabolic Partial Differential Equations

    DTIC Science & Technology

    2012-01-26

    AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Massachusetts Institute of...Technology,Department of Mechanical Engineering,Cambridge,MA,02139 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND...croissance exponentielle en eµ1T et qui sont donc inutilisables en pratique . 1. Space-time formulation We first formulate a general linear parabolic

  15. Argon Spill Trough Bellows - Leak Test

    SciTech Connect

    Jaques, A.; /Fermilab

    1990-04-30

    The four argon spill trough bellows were leak tested with helium during the week of March 12, 1990. Three passed without incident, but the fourth was found to have a leak in the weld at one of the ring/clamps. The hole was approximately 1/32-inch in diameter (a likely result of a welding burn through) and located on an inflexible portion of the bellows, the ring/clamp. Frank Juravic, who conducted the tests, suggested using grey structural epoxy to plug the leak. The epoxy is metallic with some inherent flexibility. The epoxy was applied and the bellows retested in the same manner as before. The repair was a success as the bellows proved to be leaktight. The bellows were then put in their original shipping crates and placed in storage at Lab C. Included in this report is the manufacturer's spec sheets on the bellows, a copy of the Quality Control Report form and a sketch of the test setup with an explanation of the procedure. On the bellows data sheet entitled 'Analysis of Stress in Bellows', the analysis output is obtained through a theoretical bellows program that uses quadratic equations to approximate characteristic curves for such data as axial, lateral and angular movement and spring rates. The program is best suited for bellows with a wall thickness of at least 0.015-inch and an operating pressure significantly above atmospheric. Thus EJS Inc. warned that the output data would not be very accurate in some instances. The data given on the EJS Inc. sketch sheet should be taken as accurate, though, for it was taken from the actual bellows delivered. The 72-inch length includes the 64.64-inch of bellows section, the (3) 1/2-inch ring/clamps and the (2) 1-1/2-inch end bands. The remainder of the discrepancy is accounted for by a 2.75-inch factory elongation of the bellows from the original free length. The 40-inch compression capability includes the 2.75-inch of factory elongation, the program determined 31.9-inch of compression from free length and 5.35-inch of

  16. 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

  17. Nonlinear modes in a complex parabolic potential

    SciTech Connect

    Zezyulin, Dmitry A.; Alfimov, Georgy L.; Konotop, Vladimir V.

    2010-01-15

    We report on analysis of the mode structure of a Bose-Einstein condensate loaded in a complex parabolic potential and subjected to a constant pump. Stationary solutions for the positive and negative scattering lengths are addressed. In the case of a positive scattering length and large number of atoms the ground state is described by the Thomas-Fermi distribution, whose properties in the presence of the dissipation are very different from its conservative counterpart. It is shown that for a positive scattering length only the ground state appears to be stable.

  18. Parabolic Refined Invariants and Macdonald Polynomials

    NASA Astrophysics Data System (ADS)

    Chuang, Wu-yen; Diaconescu, Duiliu-Emanuel; Donagi, Ron; Pantev, Tony

    2015-05-01

    A string theoretic derivation is given for the conjecture of Hausel, Letellier and Rodriguez-Villegas on the cohomology of character varieties with marked points. Their formula is identified with a refined BPS expansion in the stable pair theory of a local root stack, generalizing previous work of the first two authors in collaboration with Pan. Haiman's geometric construction for Macdonald polynomials is shown to emerge naturally in this context via geometric engineering. In particular this yields a new conjectural relation between Macdonald polynomials and refined local orbifold curve counting invariants. The string theoretic approach also leads to a new spectral cover construction for parabolic Higgs bundles in terms of holomorphic symplectic orbifolds.

  19. 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.

  20. Chemical characteristics of water masses in the Rockall Trough

    NASA Astrophysics Data System (ADS)

    McGrath, Triona; Nolan, Glenn; McGovern, Evin

    2012-03-01

    Direct observations of physical and chemical data in the Rockall Trough during February of 2008, 2009 and 2010 are presented. Results are compared to a similar WOCE transect, AR24, completed in November/December 1996. Temperature and salinity data have been used to identify the water masses present in the Trough, and have been combined with nutrient (nitrate, nitrite, phosphate, silicate) and oxygen data to produce a table outlining the chemical characteristics of each of the water masses. Eastern North Atlantic Water (ENAW) moving north through the Trough gains nutrients from a branch of the North Atlantic Current (NAC). Mediterranean Water (MW) was identified as a warm saline core, with characteristically low oxygen and low preformed nutrients along the Irish continental shelf break near 53°N. Found at a similar density level at the southern entrance to the Trough, Sub Arctic Intermediate Water (SAIW) has relatively high oxygen and preformed nutrients, likely entrained from the subpolar gyre when it was formed. LSW was identified as a prominent water mass between 1500 and 2000 m deep, with characteristically high oxygen content. Lower silicate, and to a lesser extent preformed nitrate, in 2009 coincide with a freshening of Labrador Sea Water (LSW) relative to other years, and could indicate a stronger influence from the Labrador Current when it was formed. Finally, traces of Antarctic Bottom Water (AABW) were found as far north as 53°N, indicated by a sharp increase in nutrient concentrations, particularly silicate in the deepest parts of the Trough.

  1. 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

  2. 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.

  3. Development of a premidnight trough observed with EISCAT

    NASA Astrophysics Data System (ADS)

    Voiculescu, Mirela; Nygren, Tuomo; Aikio, Anita; Kuula, Ritva

    An EISCAT UHF experiment scanning through 360 in azimuth with a fixed elevation was carried out on 9 November 1987 and observed a F region ionospheric trough in the post-noon and evening sectors. Since the radar rotates with the Earth, beams with different directions from subsequent scans meet in the same MLT-Mlat pixel in non-rotating frame. Measurements were combined to give a single value of electron density and ion/electron temperature in each pixel. The ion velocity full vector could also be calculated, since each measurement in a given bin corresponds to a different beam direction. Such calculations were possible because the geomagnetic conditions during the entire time of the experiment were quiet enough for assuming a quasi-stationary ionosphere. It was found that the trough minimum is due to recombination of F region plasma flowing for a long time within the dusk convection cell beyond the terminator. The northern edge of the trough is associated with particle precipitation and the southern edge is caused by plasma flow from the sunlit part of the F region. The southern edge is steeper than the northern edge. Both ion and electron temperatures have minima within the trough region. Plasma horizontal transport and convection pattern at the time of observations play an important role in maintaining the low density inside the trough.

  4. Focusing parabolic guide for very small samples

    NASA Astrophysics Data System (ADS)

    Hils, T.; Boeni, P.; Stahn, J.

    2004-07-01

    Modern materials can often only be grown in small quantities. Therefore, neutron-scattering experiments are difficult to perform due to the low signal. In order to increase the flux at the sample position, we have developed the concept of a small focusing guide tube with parabolically shaped walls that are coated with supermirror m=3. The major advantage of parabolic focusing is that the flux maximum occurs not at the exit of the tube. It occurs at the focal point that can be several centimeters away from the exit of the tube. We show that an intensity gain of 6 can easily be obtained. Simulations using the software package McStas demonstrate that gain factors up to more than 50 can be realised on a spot size of approximately 1.2 mm diameter. For PGAA we expect flux gains of up to three orders of magnitude if multiplexing is used. We show that elliptic ballistic guides lead to flux gains of more than 6.

  5. The design of parabolic cylindrical antenna with light emitting plasma

    NASA Astrophysics Data System (ADS)

    Zeng, Jie; Shi, Jia-ming; Liu, Yang; Zhang, Ji-kui; Li, Zhi-gang

    2016-11-01

    By using the electromagnetic wave reflection characteristics of the plasma, the plasma can be used to design the reflector antenna. the paper designs a metal parabolic cylindrical antenna and a plasma luminescence parabolic cylindrical antenna, and uses CST software calculating the radiative properties of them, analysising the key parameters of plasma luminescence parabolic cylindrical antenna radiation and scattered radiation resistance. Simulation results show that selecting appropriate plasma column spacing, plasma frequency, collision frequency, the plasma luminescence parabolic cylindrical antenna has the same radiation performance with metal parabolic antenna, at the same time, the RCS of plasma antenna in working and not working are smaller compared with the metal antenna, especially in plasma does not work ,the bistatic RCS reduced to a greater extent than the previous related literature design.

  6. 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.

  7. 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.

  8. Steam engine research for solar parabolic dish

    NASA Astrophysics Data System (ADS)

    Demler, R. L.

    1981-05-01

    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.

  9. 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.

  10. 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.

  11. Nuclear blast resistant parabolic antenna feed means

    SciTech Connect

    Dumas, T. A.; Buchmeyer, S. K.; Vet, M.

    1985-03-19

    The aftermath of a nuclear explosion generates a large amount of heat or infrared energy. When this heat is received by a parabolic reflector type antenna, the level of heat concentrated on the focal area of the feed is very intense. The present invention utilizes a highly heat conductive ceramic plug between the splash plate at the focal area of the feed and the waveguide so that heat can be readily conducted away from the splash plate and thereby minimize operational destruction of this splash plate due to thermal overload. The heat conductor material is a ceramic which is substantially transparent to RF signals being received by, or transmitted from the waveguide of the antenna system.

  12. 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.

  13. 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.

  14. Infant asphyxia, soft mattresses, and the "trough" effect.

    PubMed

    Combrinck, Marais; Byard, Roger W

    2011-09-01

    Although unexpected infant death in a cot has traditionally been attributed to sudden infant death syndrome, careful evaluation of death scenes and sleeping environments has increasingly identified deaths due to accidental asphyxia from so-called sleeping accidents. The case of a 5-month-old infant boy who was found facedown and unresponsive in a wooden portable cot with a sagging canvas base is reported to illustrate another potentially lethal situation. Although the autopsy revealed no specific findings, examination of the cot showed a significant depression caused by the sagging canvas base that was exacerbated by a soft-foam mattress and layers of bedding. Once in the trough, the infant would not have been able to extricate himself. Death was therefore attributed to accidental suffocation due to the infant's position resulting in contact of the mouth and face with soft bedding. In addition to again demonstrating the potential dangers of using old second-hand cots, this case clearly shows the problems that may exist when soft and sagging bedding forms a central trough that may entrap an infant. Death scene investigators should specifically comment on the presence of such troughs and measure of depth of the trough and/or cot base to provide some quantification of the degree of concavity present.

  15. 9 CFR 91.27 - Troughs and hayracks.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... and pens aboard an ocean vessel shall be equipped with proper troughs for feeding and watering animals... the inspector. The feeding of hay to the animals on ocean vessels may be by means of dispensing the hay from racks or nets or by placing the hay on the floor of the pens in which the animals...

  16. 9 CFR 91.27 - Troughs and hayracks.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... and pens aboard an ocean vessel shall be equipped with proper troughs for feeding and watering animals... the inspector. The feeding of hay to the animals on ocean vessels may be by means of dispensing the hay from racks or nets or by placing the hay on the floor of the pens in which the animals...

  17. 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... the inspector. The feeding of hay to the animals on ocean vessels may be by means of dispensing the hay from racks or nets or by placing the hay on the floor of the pens in which the animals...

  18. 9 CFR 91.27 - Troughs and hayracks.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... and pens aboard an ocean vessel shall be equipped with proper troughs for feeding and watering animals... the inspector. The feeding of hay to the animals on ocean vessels may be by means of dispensing the hay from racks or nets or by placing the hay on the floor of the pens in which the animals...

  19. 9 CFR 91.27 - Troughs and hayracks.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... and pens aboard an ocean vessel shall be equipped with proper troughs for feeding and watering animals... the inspector. The feeding of hay to the animals on ocean vessels may be by means of dispensing the hay from racks or nets or by placing the hay on the floor of the pens in which the animals...

  20. 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.

  1. 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...

  2. 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

  3. Microphotonic parabolic light directors fabricated by two-photon lithography

    SciTech Connect

    Atwater, J. H.; Spinelli, P.; Kosten, E.; Parsons, J.; Van Lare, C.; Van de Groep, J.; Garcia de Abajo, J.; Polman, A.; Atwater, H. A.

    2011-10-10

    We have fabricated microphotonic parabolic light directors using two-photon lithography, thin-film processing, and aperture formation by focused ion beam lithography. Optical transmission measurements through upright parabolic directors 22 μm high and 10 μm in diameter exhibit strong beam directivity with a beam divergence of 5.6°, in reasonable agreement with ray-tracing and full-field electromagnetic simulations. The results indicate the suitability of microphotonic parabolic light directors for producing collimated beams for applications in advanced solar cell and light-emitting diode designs.

  4. 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.

  5. Wind loads and local pressure distributions on parabolic dish solar collectors

    NASA Astrophysics Data System (ADS)

    Peterka, J. A.; Derickson, R. G.; Cermak, J. E.

    1990-05-01

    The research and development described in this document was conducted within the U.S. Department of Energy's Solar Thermal Technology Program. The goal of this program is to advance the engineering and scientific understanding of solar thermal technology and the establish the technology base from which private industry can develop solar thermal power production options for introduction into the competitive energy market. This report presents the results of wind-tunnel tests supported through the Solar Energy Research Institute (SERI) by the Office of Solar Thermal Technology of the U.S. Department of Energy as part of the SERI research effort on innovative concentrators. As gravity loads on drive mechanisms are reduced through stretched-membrane technology, the wind-load contribution of the required drive capacity increases in percentage. Reduction of wind loads can provide economy in support structure and collector drive. Wind-tunnel tests have been directed at finding methods to reduce wind loads on parabolic dish collectors. The tests investigated the mean and peak forces, moments and local pressure distributions. A significant increase in the understanding and prediction of peak parabolic dish wind loads and their reduction within a field was achieved.

  6. Finite Time Blowup for Parabolic Systems in Two Dimensions

    NASA Astrophysics Data System (ADS)

    Mooney, Connor

    2017-03-01

    We construct examples of finite time singularity from smooth data for linear uniformly parabolic systems in the plane. We obtain similar examples for quasilinear systems with coefficients that depend only on the solution.

  7. 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

  8. 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

  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. 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.

  11. Comparison of large aperture telescopes with parabolic and spherical primaries

    NASA Technical Reports Server (NTRS)

    Korsch, D.

    1986-01-01

    Quasi-Cassegrain-type four-mirror telescopes are compared to conventional two-mirror Cassegrain telescopes for use as high performance, very large aperture space telescopes. Spherical and parabolic primaries with continuous as well as segmented surfaces are considered. Imaging characteristics and misalignment sensitivities serve as the principal criteria of comparison. The evaluation shows that parabolic primaries yield superior wide-field performance, whereas spherical primaries hold distinct advantages regarding manufacturability and regarding certain alignment aspects in the case of segmentation.

  12. 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.

  13. 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.

  14. 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.

  15. Visually-induced tilt during parabolic flights.

    PubMed

    Cheung, B S; Howard, I P; Money, K E

    1990-01-01

    A helmet-mounted visual display system was used to study visually induced sensations of self-motion (vection) about the roll, pitch and yaw axes under normal gravity condition (1g) and during the microgravity and hypergravity phases of parabolic flights aboard the NASA KC-135 aircraft. Under each gravity condition, the following parameters were investigated: (1) the subject's perceived body vertical with eyes closed and with eyes open gazing at a stationary random dot display; (2) the magnitude of sensations of body tilt with respect to the subjective vertical, while the subject viewed displays rotating about the roll, pitch and yaw axes; (3) the magnitude of vection; (4) latency of vection. All eleven subjects perceived a definite "up and down" orientation throughout the course of the flight. During the microgravity phase, the average magnitudes of perceived body tilt and self-motion increased significantly, and there was no significant difference in vection latency. These results show that there is a rapid onset of increased dependence on visual inputs for perception of self-orientation and self-motion in weightlessness, and a decreased dependence on otolithic and somatosensory graviceptive information. Anti-motion sickness drugs appear not to affect the parameters measured.

  16. The 1D parabolic-parabolic Patlak-Keller-Segel model of chemotaxis: The particular integrable case and soliton solution

    NASA Astrophysics Data System (ADS)

    Shubina, Maria

    2016-09-01

    In this paper, we investigate the one-dimensional parabolic-parabolic Patlak-Keller-Segel model of chemotaxis. For the case when the diffusion coefficient of chemical substance is equal to two, in terms of travelling wave variables the reduced system appears integrable and allows the analytical solution. We obtain the exact soliton solutions, one of which is exactly the one-soliton solution of the Korteweg-de Vries equation.

  17. Coincident observations of ionospheric troughs and the equatorial plasmapause

    NASA Technical Reports Server (NTRS)

    Grebowsky, J. M.; Maynard, N. C.; Tulunay, Y. K.; Lanzerotti, L. J.

    1976-01-01

    Electron-density observations made in the topside ionosphere by the Ariel 4 and Isis 2 satellites are examined in conjunction with results obtained by Explorer 45 when it traversed the near-equatorial plasmapause with one hour (both UT and MLT) of the Ariel and Isis traversals of the same L coordinate. Both dusk and night observations are analyzed, and an attempt is made to show that depressions in ionospheric electron density occur in the vicinity of the plasmapause field line. It is concluded that the electron distributions observed in the electron-density troughs at 550 km near dusk by Ariel and at 1400 km near midnight by Isis do not always parallel variations in the light-ion distribution inferred from the Explorer plasmapause traversals and that there appears to be no specific feature of the main ionospheric trough which can be used to identify the plasmapause field line except in a statistical sense.

  18. 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…

  19. 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

  20. 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.

  1. 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.

  2. The nature of the crust under Cayman Trough from gravity

    USGS Publications Warehouse

    ten Brink, U.S.; Coleman, D.F.; Dillon, William P.

    2002-01-01

    Considerable crustal thickness variations are inferred along Cayman Trough, a slow-spreading ocean basin in the Caribbean Sea, from modeling of the gravity field. The crust to a distance of 50 km from the spreading center is only 2-3 km thick in agreement with dredge and dive results. Crustal thickness increases to ???5.5 km at distances between 100 and 430 km west of the spreading center and to 3.5-6 km at distances between 60 and 370 km east of the spreading center. The increase in thickness is interpreted to represent serpentinization of the uppermost mantle lithosphere, rather than a true increase in the volume of accreted ocean crust. Serpentinized peridotite rocks have indeed been dredged from the base of escarpments of oceanic crust rocks in Cayman Trough. Laboratory-measured density and P-wave speed of peridotite with 40-50% serpentine are similar to the observed speed in published refraction results and to the inferred density from the model. Crustal thickness gradually increases to 7-8 at the far ends of the trough partially in areas where sea floor magnetic anomalies were identified. Basement depth becomes gradually shallower starting 250 km west of the rise and 340 km east of the rise, in contrast to the predicted trend of increasing depth to basement from cooling models of the oceanic lithosphere. The gradual increase in apparent crustal thickness and the shallowing trend of basement depth are interpreted to indicate that the deep distal parts of Cayman Trough are underlain by highly attenuated crust, not by a continuously accreted oceanic crust. Published by Elsevier Science Ltd.

  3. 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.

  4. Laser welding on trough panel: 3D body part

    NASA Astrophysics Data System (ADS)

    Shirai, Masato; Hisano, Hirohiko

    2003-03-01

    Laser welding for automotive bodies has been introduced mainly by European car manufacturers since more than 10 years ago. Their purposes of laser welding introduction were mainly vehicle performance improvement and lightweight. And laser welding was applied to limited portion where shapes of panels are simple and easy to fit welded flanges. Toyota also has introduced laser welding onto 3 dimensional parts named trough panel since 1999. Our purpose of the introduction was common use of equipment. Trough panel has a complex shape and different shapes in each car type. In order to realize common use of welding equipment, we introduced parts locating equipment which had unique, small & simple jigs fo each car type and NC (Numerical Controlled) locators and air-cooled small laser head developed by ourselves to the trough welding process. Laser welding replaced spot welding and was applied linearly like stitches. Length of laser welding was determined according to comparison with statistic tensile strength and fatigue strength of spot welding.

  5. 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.

  6. Airflow and sand transport variations within a backshore parabolic dune plain complex: NE Graham Island, British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Anderson, Jeffrey L.; Walker, Ian J.

    2006-07-01

    Onshore aeolian sand transport beyond the beach and foredune is often overlooked in the morphodynamics and sediment budgets of sandy coastal systems. This study provides detailed measurements of airflow, sand transport (via saltation and modified suspension), vegetation density, and surface elevation changes over an extensive (325 × 30 m) "swath" of a backshore foredune-parabolic dune plain complex. Near-surface (30 cm) wind speeds on the backshore ranged from 4.3 to 7.3 m s - 1 , gusting to 14.0 m s - 1 . Oblique onshore flow is steered alongshore near the incipient foredune then landward into a trough blowout where streamline compression, flow acceleration to 1.8 times the incident speed, and increasing steadiness occur. Highest saltation rates occur in steady, topographically accelerated flow within the blowout. As such, the blowout acts as a conduit to channel flow and sand through the foredune into the foredune plain. Beyond the blowout, flow expands, vegetation roughness increases, and flow decelerates. Over the foredune plain, localized flow steering and acceleration to 1.6 times the incident speed occurs followed by a drop to 40% of incident flow speed in a densely vegetated zone upwind of an active parabolic dune at 250 m from the foredune. Sediment properties reflect variations in near-surface flow and transport processes. Well-sorted, fine skewed backshore sands become more poorly sorted and coarse skewed in the blowout due to winnowing of fines. Sorting improves and sands become fine skewed over the foredune plain toward the parabolic dune due to grainfall of finer sands winnowed from the beach and foredune. During the fall-winter season, significant amounts of sand (up to 110 kg m - 2 ) are transported via modified suspension and deposited as grainfall up to 300 m landward of the foredune. No distinct trend in grainfall was found, although most fell on the depositional lobe of the blowout and at 200 m near an isolated, active parabolic dune. Grainfall

  7. 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.

  8. 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

  9. Results of the parabolic flight tests of the rapunzel deployer

    NASA Astrophysics Data System (ADS)

    Sabath, D.; Krischke, M.; Kast, W.; Kowalczyk, M.; Kruijff, M.; van der Heide, E.

    The tether assisted re-entry of small payloads is a highly interesting tool for space transportation especially for the return of small payloads from Space Station ISSA. The small tether mission Rapunzel was initiated in 1991 by the Institute of Astronautics, TU München and the Kayser-Threde Company, to design a low cost and feasible tether experiment for the verification of the tether assisted re-entry. Together with the Samara State Aerospace University, Russia, a mission concept on a Russian Resurs or Photon capsule was developed. Based on this mission a deployer has been designed, mainly based on technology of the textile industry, which insures high reliability at low cost. Recently a similar configuration is being discussed for the ESA-TSE mission. The main work during the recent time was the development and test of the breadboard model of the deployer system. After successfully completing initial ground tests with the deployer, further tests during the ESA Parabolic Flight campaign in November 1995 were conducted. After a short introduction of the overall mission scenario, the planned configuration in orbit, this paper will present the results of the microgravity test campaign onboard the KC-135 aircraft and compare them with the ground test. The deployer showed a good performance during all tests, including ejection of the end-mass, deployment, and braking. Problems that occurred during the tests will be discussed, and solutions for the detected flaws and the results of the redesign now in progress will be presented. These verifications have shown the feasibility of the concept and will lay the base for the planned development of the flight model of the deployer.

  10. Model Predictive Control for Nonlinear Parabolic Partial Differential Equations

    NASA Astrophysics Data System (ADS)

    Hashimoto, Tomoaki; Yoshioka, Yusuke; Ohtsuka, Toshiyuki

    In this study, the optimal control problem of nonlinear parabolic partial differential equations (PDEs) is investigated. Optimal control of nonlinear PDEs is an open problem with applications that include fluid, thermal, biological, and chemically-reacting systems. Model predictive control with a fast numerical solution method has been well established to solve the optimal control problem of nonlinear systems described by ordinary differential equations. In this study, we develop a design method of the model predictive control for nonlinear systems described by parabolic PDEs. Our approach is a direct infinite dimensional extension of the model predictive control method for finite-dimensional systems. The objective of this paper is to develop an efficient algorithm for numerically solving the model predictive control problem of nonlinear parabolic PDEs. The effectiveness of the proposed method is verified by numerical simulations.

  11. 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.

  12. Organic geothermometry of petroleum from Escanaba Trough, offshore northern California

    USGS Publications Warehouse

    Kvenvolden, K.A.; Rapp, J.B.; Hostettler, F.D.; David, King J.; Claypool, G.E.

    1988-01-01

    We have measured the extent of hopane and sterane isomerization and of monoaromatic-steroid-hydrocarbon aromatization in a sample of hydrothermally derived petroleum from the Escanaba Trough, a sediment-covered, volcanically active ridge axis. The results, along with kinetic parameters, predict the possible time-temperature history of the petrolum-forming process for this sample. The extent of these reactions is consistent with petroleum formation by intense heating (about 300-350??C) if the time period of this heating was as short as about 100 yr. Such a time scale is reasonable for hydrothermal-discharge events associated with ridge-crest volcanism. ?? 1987.

  13. On global solutions for quasilinear one-dimensional parabolic problems with dynamical boundary conditions

    NASA Astrophysics Data System (ADS)

    Gvelesiani, Simon; Lippoth, Friedrich; Walker, Christoph

    2015-12-01

    We provide sufficient and almost optimal conditions for global existence of classical solutions in parabolic Hölder spaces to quasilinear one-dimensional parabolic problems with dynamical boundary conditions.

  14. A Study of Mobile Trough Genesis Over The Yellow Sea-East China Sea Region

    DTIC Science & Technology

    2011-07-21

    Mongolian Plateau. The maximum that extends over the Yellow Sea and East China Sea is the only region of enhanced mobile trough formation which is...Gammon used PTD to further investigate mobile troughs and extratropical cyclones. An investigation of mobile trough formation over the Mongolian Plateau...over the Mongolian plateau. The results from the previous studies provide a measure of confidence for this research. Two case studies were chosen using

  15. 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.

  16. Conceptual design and techno-economic assessment of integrated solar combined cycle system with DSG technology

    SciTech Connect

    Nezammahalleh, H.; Farhadi, F.; Tanhaemami, M.

    2010-09-15

    Direct steam generation (DSG) in parabolic trough collectors causes an increase to competitiveness of solar thermal power plants (STPP) by substitution of oil with direct steam generation that results in lower investment and operating costs. In this study the integrated solar combined cycle system with DSG technology is introduced and techno-economic assessment of this plant is reported compared with two conventional cases. Three considered cases are: an integrated solar combined cycle system with DSG technology (ISCCS-DSG), a solar electric generating system (SEGS), and an integrated solar combined cycle system with HTF (heat transfer fluid) technology (ISCCS-HTF). This study shows that levelized energy cost (LEC) for the ISCCS-DSG is lower than the two other cases due to reducing O and M costs and also due to increasing the heat to electricity net efficiency of the power plant. Among the three STPPs, SEGS has the lowest CO{sub 2} emissions, but it will operate during daytime only. (author)

  17. 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.

  18. Early diagenesis of lead in Laurentian Trough sediments

    NASA Astrophysics Data System (ADS)

    Gobeil, Charles; Silverberg, Norman

    1989-08-01

    The depth distributions of various solid-phase and porewater fractions of Pb, Fe and Cd in boxcores from three stations in the Laurentian Trough demonstrate that Pb is subject to early diagenetic change. High total-Pb concentrations, compared to background levels, indicate that much of the Pb in these cores is of anthropogenic origin. Patterns of mobilization and fixation, and of changes in the chemical reactivity towards extradants, are consistent from core to core. Pb is mobilized both near the sediment surface and at intermediate depth. In these zones dissolved Pb concentrations attain levels of 8-13.5 nM, which are two orders of magnitude greater than in the overlying bottom waters of the Laurentian Trough (0.1 nM). A fraction of Pb, soluble in a pH 5 sodium acetate-acetic acid solution, is produced diagenetically within the sediment. It is most abundant at intermediate depth, where it accounts for as much as 31% of the total Pb. Another fraction, soluble in hydroxylamine hydrochloride-acetic acid solution, decreases in abundance with depth. Flux calculations indicate that significant amounts of Pb are subject to postdepositional transformation. Parallels in the vertical distribution of the various fractions suggest that some Pb, like Cd, is mobilized near the sediment surface during the aerobic degradation of organic matter and that other forms are implicated in the redox-controlled cycles of Fe diagenesis.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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).

  4. On an algorithm for solving parabolic and elliptic equations

    NASA Astrophysics Data System (ADS)

    D'Ascenzo, N.; Saveliev, V. I.; Chetverushkin, B. N.

    2015-08-01

    The present-day rapid growth of computer power, in particular, parallel computing systems of ultrahigh performance requires a new approach to the creation of models and solution algorithms for major problems. An algorithm for solving parabolic and elliptic equations is proposed. The capabilities of the method are demonstrated by solving astrophysical problems on high-performance computer systems with massive parallelism.

  5. The ellipse in parabolic motion: An undergraduate experiment

    NASA Astrophysics Data System (ADS)

    Carrillo-Bernal, M. A.; Mancera-Piña, P. E.; Cerecedo-Núñez, H. H.; Padilla-Sosa, P.; Núñez-Yépez, H. N.; Salas-Brito, A. L.

    2014-04-01

    We present a simple method of experimentally studying the elliptic shape of the joined apices of parabolic projectile trajectories in the undergraduate laboratory. The experimental data agrees well with theoretical results, and we find that this experiment provides an interesting twist to the venerable undergraduate experiment on projectile motion.

  6. Strict parabolicity of the multifractal spectrum at the Anderson transition

    NASA Astrophysics Data System (ADS)

    Suslov, I. M.

    2016-11-01

    Using the well-known "algebra of multifractality," we derive the functional equation for anomalous dimensions Δ q , whose solution Δ = χ q( q-1) corresponds to strict parabolicity of the multifractal spectrum. This result demonstrates clearly that a correspondence of the nonlinear σ-models with the initial disordered systems is not exact.

  7. Proton driven plasma wakefield generation in a parabolic plasma channel

    NASA Astrophysics Data System (ADS)

    Golian, Y.; Dorranian, D.

    2016-11-01

    An analytical model for the interaction of charged particle beams and plasma for a wakefield generation in a parabolic plasma channel is presented. In the suggested model, the plasma density profile has a minimum value on the propagation axis. A Gaussian proton beam is employed to excite the plasma wakefield in the channel. While previous works investigated on the simulation results and on the perturbation techniques in case of laser wakefield accelerations for a parabolic channel, we have carried out an analytical model and solved the accelerating field equation for proton beam in a parabolic plasma channel. The solution is expressed by Whittaker (hypergeometric) functions. Effects of plasma channel radius, proton bunch parameters and plasma parameters on the accelerating processes of proton driven plasma wakefield acceleration are studied. Results show that the higher accelerating fields could be generated in the PWFA scheme with modest reductions in the bunch size. Also, the modest increment in plasma channel radius is needed to obtain maximum accelerating gradient. In addition, the simulations of longitudinal and total radial wakefield in parabolic plasma channel are presented using LCODE. It is observed that the longitudinal wakefield generated by the bunch decreases with the distance behind the bunch while total radial wakefield increases with the distance behind the bunch.

  8. 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.

  9. Low-crosstalk Si arrayed waveguide grating with parabolic tapers.

    PubMed

    Ye, Tong; Fu, Yunfei; Qiao, Lei; Chu, Tao

    2014-12-29

    A silicon arrayed waveguide grating (AWG) with low channel crosstalk was demonstrated by using ultra-short parabolic tapers to connect the AWG's free propagation regions and single-mode waveguides. The tapers satisfied the requirements of low-loss mode conversion and lower channel crosstalk from the coupling of neighboring waveguides in the AWGs. In this work, three different tapers, including parabolic tapers, linear tapers, and exponential tapers, were theoretically analyzed and experimentally investigated for a comparison of their effects when implemented in AWGs. The experimental results showed that the AWG with parabolic tapers had a crosstalk improvement up to 7.1 dB compared with the others. Based on the advantages of parabolic tapers, a 400-GHz 8 × 8 cyclic AWG with 2.4 dB on-chip loss and -17.6~-25.1 dB crosstalk was fabricated using a simple one-step etching process. Its performance was comparable with that of existing AWGs with bi-level tapers, which require complicated two-step etching fabrication processes.

  10. 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.

  11. 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.

  12. 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

  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. IR spectrometer using 90-degree off-axis parabolic mirrors

    NASA Astrophysics Data System (ADS)

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

    2008-08-01

    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 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.

  16. Measurement uncertainty in the profile detection on solar troughs

    NASA Astrophysics Data System (ADS)

    Sansoni, P.; Fontani, D.; Francini, F.; Toccafondi, S.; Messeri, M.; Coraggia, S.; Mercatelli, L.; Jafrancesco, D.; Sani, E.

    2013-04-01

    Surface profile control on solar concentrators is fundamental since the mirror can be imperfectly manufactured. Optical profilometric measurements are generally addressed to detect small localised irregularities. The paper presents an optical profilometer for linear solar collectors, which are typically employed in thermal plants and more recently in concentrating photovoltaic systems. The profilometer includes a source of parallel rays and a target placed at the collector focal distance. It was developed simulating profile measurements on linear parabolic mirrors; then the method was validated by tests on a practical realisation. The device examines the reflector surface operating on a plane transversal to the linear collector axis; then the detection is repeated displacing the optical profilometer along the collector axis. This experimentation allowed to deeply examine and reduce the errors of the measurement procedure.

  17. 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

  18. 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.

  19. 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.

  20. The Daytime F Layer Trough and Its Relation to Ionospheric-Magnetospheric Convection

    DTIC Science & Technology

    1989-12-01

    intervals throughout the mum. The trough, the equatorward boundary of which wasstabe i soar gomanetc cordi t fo man horswas array. continuously throughout...of the trough is limited neither to the locale the quiet day and the curve plus points that of the moderate notohecdiosofFgr2.awllbilurtdfr day. The

  1. 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.

  2. Forearc sedimentation in Terraba Trough, Costa Rica, Central America

    SciTech Connect

    Yuan, P.B.; Lowe, D.R.

    1987-05-01

    Sedimentary rocks of Terraba Trough, Costa Rica, were deposited in a forearc basin developed at an ocean-ocean convergent boundary. The basin developed in the middle to late Eocene when the Farallon plate began its subduction beneath the Caribbean plate. Shallow-water carbonates of the Brito Formation were deposited on shoals of basement blocks. These were surrounded by deeper marine areas in which volcaniclastics and carbonate debris accumulated. The Brito Formation consists of algal-foraminiferal packstone to grainstone, rudstone, and rare wackestone formed in fore-slope, carbonate buildup, and open platform environments in a warm, tropical sea. The Eocene Brito Formation is overlain by rocks of the upper Oligocene Rio Claro Member of the Terraba Formation. It is composed of rhodolite and bioclastic grainstone deposited in shallow water. A combination of little subsidence, mild volcanism, and possible erosion at about 30 Ma during a global drop of sea level may be responsible for the absence of lower Oligocene rocks in the study area. After the deposition of the Rio Claro Member, the area subsided rapidly to become a trough possibly deeper than 2000 m. Sedimentation took place in deep water from sediment gravity flows. In the early to early middle Miocene, coarser sediments and thicker sand units containing coal fragments became more abundant, suggesting that the basin was gradually filled. This study indicates that the timing and degree of subsidence of the fore-arc basin and the vertical variation in lithology are closely related to the variation in convergence rate between lithospheric plates in this part of Central America and the eastern Pacific.

  3. 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.

  4. 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

  5. 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.

  6. Seasonal Variations of Mid-Latitude Ionospheric Trough Structure Observed with DEMETER and COSMIC

    NASA Astrophysics Data System (ADS)

    Matyjasiak, Barbara; Przepiórka, Dorota; Rothkaehl, Hanna

    2016-12-01

    The mid-latitude ionospheric trough is a depleted region of ionospheric plasma observed in the topside ionosphere. Its behavior can provide useful information about the magnetospheric dynamics, since its existence is sensitive to magnetospherically induced motions. Mid-latitude trough is mainly a night-time phenomenon. Both, its general features and detailed characteristics strongly depend on the level of geomagnetic disturbances, time of the day, season, and the solar cycle, among others. Although many studies provide basic information about general characteristics of the main ionospheric trough structure, an accurate prediction of the trough behavior in specific events is still understood poorly. The paper presents the mid-latitude trough characteristics with regard to the geomagnetic longitude and season during a solar activity minimum, as based on the DEMETER in situ satellite measurements and the data retrieved from FORMOSAT-3/COSMIC radio occultation measurements.

  7. 3-D supersonic combustion experiments with hydrogen in V-trough

    NASA Technical Reports Server (NTRS)

    Friedberg, R. A.; Ahmed, A.

    1982-01-01

    Both supersonic blowdown and free jet wind tunnels were used in oil flow visualization and hydrogen gas burning tests of 60- and 90-deg V-shaped trough combustion characteristics. Oil dots showed that mass outflow from the reattachment region at the bottom of the V-trough dominated flow behavior, and occupied the trough's entire length and 10% of its cross-section. Intermingled vortex pairs were also found to superimpose themselves upon the outflow, and hydrogen burning within troughs reduced missile base drag by 25%. The troughs were aligned so that their long dimensions were parallel to the airflow, and the two top edges of the V section were mounted flush with respect to the upstream flat surfaces. Step heights tested ranged from 3.4 mm to 6.25 cm.

  8. Short duration microgravity experiments in physical and life sciences during parabolic flights: the first 30 ESA campaigns.

    PubMed

    Pletser, Vladimir

    2004-11-01

    Aircraft parabolic flights provide repetitively up to 20 s of reduced gravity during ballistic flight manoeuvres. Parabolic flights are used to conduct short microgravity investigations in Physical and Life Sciences, to test instrumentation and to train astronauts before a space flight. The European Space Agency (ESA) has organized since 1984 thirty parabolic flight campaigns for microgravity research experiments utilizing six different airplanes. More than 360 experiments were successfully conducted during more than 2800 parabolas, representing a cumulated weightlessness time of 15 h 30 m. This paper presents the short duration microgravity research programme of ESA. The experiments conducted during these campaigns are summarized, and the different airplanes used by ESA are shortly presented. The technical capabilities of the Airbus A300 'Zero-G' are addressed. Some Physical Science, Technology and Life Science experiments performed during the last ESA campaigns with the Airbus A300 are presented to show the interest of this unique microgravity research tool to complement, support and prepare orbital microgravity investigations.

  9. 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.

  10. 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.

  11. 'Parabolic' trapped modes and steered Dirac cones in platonic crystals.

    PubMed

    McPhedran, R C; Movchan, A B; Movchan, N V; Brun, M; Smith, M J A

    2015-05-08

    This paper discusses the properties of flexural waves governed by the biharmonic operator, and propagating in a thin plate pinned at doubly periodic sets of points. The emphases are on the design of dispersion surfaces having the Dirac cone topology, and on the related topic of trapped modes in plates for a finite set (cluster) of pinned points. The Dirac cone topologies we exhibit have at least two cones touching at a point in the reciprocal lattice, augmented by another band passing through the point. We show that these Dirac cones can be steered along symmetry lines in the Brillouin zone by varying the aspect ratio of rectangular lattices of pins, and that, as the cones are moved, the involved band surfaces tilt. We link Dirac points with a parabolic profile in their neighbourhood, and the characteristic of this parabolic profile decides the direction of propagation of the trapped mode in finite clusters.

  12. 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.

  13. Physiologic Pressure and Flow Changes During Parabolic Flight (Pilot Study)

    NASA Technical Reports Server (NTRS)

    Pantalos, George; Sharp, M. Keith; Mathias, John R.; Hargens, Alan R.; Watenpaugh, Donald E.; Buckey, Jay C.

    1999-01-01

    The objective of this study was to obtain measurement of cutaneous tissue perfusion central and peripheral venous pressure, and esophageal and abdominal pressure in human test subjects during parabolic flight. Hemodynamic data recorded during SLS-I and SLS-2 missions have resulted in the paradoxical finding of increased cardiac stroke volume in the presence of a decreased central venous pressure (CVP) following entry in weightlessness. The investigators have proposed that in the absence of gravity, acceleration-induced peripheral vascular compression is relieved, increasing peripheral vascular capacity and flow while reducing central and peripheral venous pressure, This pilot study seeks to measure blood pressure and flow in human test subjects during parabolic flight for different postures.

  14. 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.

  15. Irrigation market for solar thermal parabolic dish systems

    NASA Astrophysics Data System (ADS)

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

    1981-09-01

    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.

  16. Parabolic dish systems at work - Applying the concepts

    NASA Technical Reports Server (NTRS)

    Marriott, A. T.

    1981-01-01

    An overview is given of parabolic dish solar concentrator application experiments being conducted by the U.S. Department of Energy. The 'engineering experiments' comprise the testing of (1) a small-community powerplant system, in conjunction with a grid-connected utility; (2) stand-alone applications at remote sites such as military installations, radar stations and villages; and (3) dish modules that can deliver heat for direct use in industrial processes. Applicability projections are based on a dish and receiver that use a Brayton engine with an engine/generator efficiency of 25% and a production level of up to 25,000 units per year. Analyses indicate that parabolic-dish power systems can potentially replace small, oil-fired power plants in all regions of the U.S. between 1985 and 1991.

  17. All-fiber ring Raman laser generating parabolic pulses

    SciTech Connect

    Kruglov, V. I.; Mechin, D.; Harvey, J. D.

    2010-02-15

    We present theoretical and numerical results for an all-fiber laser using self-similar parabolic pulses ('similaritons') designed to operate using self-similar propagation regimes. The similariton laser features a frequency filter and a Sagnac loop which operate together to generate an integrated all-fiber mode-locked laser. Numerical studies show that this laser generates parabolic pulses with linear chirp in good agreement with analytical predictions. The period for propagating similariton pulses in stable regimes can vary from one to two round trips for different laser parameters. Two-round-trip-period operation in the mode-locked laser appears at bifurcation points for certain cavity parameters. The stability of the similariton regimes has been confirmed by numerical simulations for large numbers of round trips.

  18. 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.

  19. Evolution of laser pulse shape in a parabolic plasma channel

    NASA Astrophysics Data System (ADS)

    Kaur, M.; Gupta, D. N.; Suk, H.

    2017-01-01

    During high-intensity laser propagation in a plasma, the group velocity of a laser pulse is subjected to change with the laser intensity due to alteration in refractive index associated with the variation of the nonlinear plasma density. The pulse front sharpened while the back of the pulse broadened due to difference in the group velocity at different parts of the laser pulse. Thus the distortion in the shape of the laser pulse is expected. We present 2D particle-in-cell simulations demonstrating the controlling the shape distortion of a Gaussian laser pulse using a parabolic plasma channel. We show the results of the intensity distribution of laser pulse in a plasma with and without a plasma channel. It has been observed that the plasma channel helps in controlling the laser pulse shape distortion. The understanding of evolution of laser pulse shape may be crucial while applying the parabolic plasma channel for guiding the laser pulse in plasma based accelerators.

  20. Propagation equation for tight-focusing by a parabolic mirror.

    PubMed

    Couairon, A; Kosareva, O G; Panov, N A; Shipilo, D E; Andreeva, V A; Jukna, V; Nesa, F

    2015-11-30

    Part of the chain in petawatt laser systems may involve extreme focusing conditions for which nonparaxial and vectorial effects have high impact on the propagation of radiation. We investigate the possibility of using propagation equations to simulate numerically the focal spot under these conditions. We derive a unidirectional propagation equation for the Hertz vector, describing linear and nonlinear propagation under situations where nonparaxial diffraction and vectorial effects become significant. By comparing our simulations to the results of vector diffraction integrals in the case of linear tight-focusing by a parabolic mirror, we establish a practical criterion for the critical f -number below which initializing a propagation equation with a parabolic input phase becomes inaccurate. We propose a method to find suitable input conditions for propagation equations beyond this limit. Extreme focusing conditions are shown to be modeled accurately by means of numerical simulations of the unidirectional Hertz-vector propagation equation initialized with suitable input conditions.

  1. 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.

  2. 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.

  3. The O(+) Density Trough at 5000 km Altitude in the Polar Cap

    NASA Technical Reports Server (NTRS)

    Zeng, W.; Horwitz, J. L.; Craven, P. D.; Rich, F. J.; Moore, T. E.

    2004-01-01

    At altitudes near 5000 km over the southern polar cap region of the terrestrial magnetosphere/ionosphere, the Thermal Ion Dynamics Experiment (TIDE) on board the Polar satellite has observed O(+) ion density trough regions, in which the densities were at least one order of magnitude lower than the surrounding O(+) densities. In the 0" density trough regions, the estimated O+ densities were generally lower than 0.01 per cc. The boundaries between normal density level regions and the trough density regions were usually abrupt transitions. From 1 December 1997 to 30 November 1998, polar cap O(+) troughs in Polar/TIDE observations occurred at a frequency of about 48%. Statistical examination of the Polar perigee observations from 1 December 1997 to 30 November 1998 shows that the Polar perigee passes evenly covered the southern polar cap region, while the O(+) density trough was always located on the nightside portion of the polar cap magnetosphere/ionosphere, and that invariant latitude spans of such troughs could be as large as 23 deg. in extent. The trough occurrence displayed a strong seasonal dependence; in the winter season (e.g., for July in the Southern Hemisphere) the O(+) ion density trough occurrence frequency ranged up to 92%, while in the summer season (e.g., for January in the Southern Hemisphere) it decreased to as low as 15%. Our statistical results show that the trough occurrence was generally anticorrelated with solar wind dynamic pressure in the solar wind dynamic pressure range 0.8 - 2.6 nanopascal. The O(+) ion density trough occurrence appeared relatively independent of the geomagnetic Kp index, IMF Bz, and By conditions. However, as suggested by the seasonal dependence, the O(+) ion density trough occurrence was strongly related to the solar zenith angle (SZA). In the SZA range 50 deg. to 125 deg., the trough occurrence increased monotonically with SZA. In addition, we sought to determine consistent density and velocity signatures at lower

  4. Geochemical features of trace and rare earth elements of pumice in middle Okinawa Trough and its indication of magmatic process

    NASA Astrophysics Data System (ADS)

    Zhai, Shikui; Guo, Kun; Zong, Tong; Yu, Zenghui; Wang, Shujie; Cai, Zongwei; Zhang, Xia

    2017-04-01

    Pumice, the most widely distributed volcanic rock in Okinawa Trough, is loose and porous. Since its formation, it has definitely suffered from the denudation of the sea to different degrees. In order to truly reveal the geochemical features of pumice, we choose the method of mineral separation. Firstly, the phenocryst is separated from glass. Then the phenocryst is divided into light and heavy mineral compositions. By ICP-MS (inductively coupled plasma mass spectrometry) analytical technology, the contents of trace and rare earth elements in the whole pumice, the glass and the heavy and light mineral compositions are determined respectively. By researching the elemental geochemical features, the magma dynamic processes are found. It shows that the initial magma for the pumice in Okinawa Trough came from the depleted mantle, from which the N-MORB (normal type of mid-ocean ridge basalt) is formed, homologous with the local basalts. But they are formed in different periods of magma crystal fractionation. Featured with sufficient crystal fractionation for pumice, it is found that the earlier crystallizing minerals are olivine, plagioclase and pyroxene. The pumice magma, formed from the depleted mantle, was mixed with additional subduction-related materials (components), and contaminated with the mass from upper crust when it rose up into the crust. As the Okinawa Trough is a back-arc basin in its early back-arc spreading stage, its magmatism has a series of its own unique characteristics, different from not only the mid-ocean ridge expansion, but also the mature back-arc basin.

  5. Performance of a blood chemistry analyzer during parabolic flight.

    PubMed

    Spooner, B S; Claassen, D E; Guikema, J A

    1990-01-01

    We have tested the performance of the VISION System Blood Analyzer, produced by Abbott Laboratories, during parabolic flight on a KC-135 aircraft (NASA 930). 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, we 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

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

    PubMed

    Latham, R D; Fanton, J W; White, C D; Vernalis, M 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 conditions. The result is an increase in blood volume in the thoracic and cardiac chambers. This increase in central volume shift should result in an increase in central atrial filling pressures. However, experimental data has been somewhat contradictory and nonconclusive to date. Early investigations of peripheral venous pressure and estimates of central venous pressure (CVP) from these data did not show an increase in CVP in the microgravity condition. However, CVP recorded in human volunteers during the parabolic flight by Norsk revealed an increase in CVP during the microgravity state. On the June 1991 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 subjects had increased CVP recordings and two other subjects had decreased CVP measurements. In April 1991, our laboratory performed parabolic flight studies in several chronic-instrumented baboon subjects. It was again noted that centrally recorded right atrial pressure varied with exposure to microgravity, some animals having an increase and others having a decrease. Thus, data presently available has demonstrated a variable response in the mechanism not clearly defined. In April 1992, we determined a test hypothesis relating the possible mechanism of these variable pressure responses to venous pressure-volume relationships.

  15. 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.

  16. Parabolic similariton Yb-fiber laser with triangular pulse evolution

    NASA Astrophysics Data System (ADS)

    Wang, Sijia; Wang, Lei

    2016-04-01

    We propose a novel mode-locked fiber laser design which features a passive nonlinear triangular pulse formation and self-similar parabolic pulse amplification intra cavity. Attribute to the nonlinear reshaping progress in the passive fiber, a triangular-profiled pulse with negative-chirp is generated and paved the way for rapid and efficient self-similar parabolic evolution in a following short-length high-gain fiber. In the meanwhile, the accompanied significantly compressed narrow spectrum from this passive nonlinear reshaping also gives the promise of pulse stabilization and gain-shaping robustness without strong filtering. The resulting short average intra-cavity pulse duration, low amplified spontaneous emission (ASE) and low intra-cavity power loss are essential for the low-noise operation. Simulations predict this modelocked fiber laser allows for high-energy ultra-short transform-limited pulse generation exceeding the gain bandwidth. The output pulse has a de-chirped duration (full-width at half maximum, FWHM) of 27 fs. In addition to the ultrafast laser applications, the proposed fiber laser scheme can support low-noise parabolic and triangular pulse trains at the same time, which are also attractive in optical pulse shaping, all-optical signal processing and high-speed communication applications.

  17. 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

  18. 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.

  19. A new ESA educational initiative: Euro Space Center class teachers in microgravity during parabolic flights

    NASA Astrophysics Data System (ADS)

    Pletser, Vladimir; Paulis, Pierre Emmanuel; Loosveldt, Edwin; Gering, Dominique; Body, Mireille; Schewijck, Robert

    2005-12-01

    Since 1984, the European Space Agency (ESA) has organized 30 aircraft parabolic flight campaigns in the frame of its Microgravity Programme to perform short duration scientific and technological experiments. On each campaign, ESA invites journalists to report to the general public on the research work conducted in weightlessness. A new initiative was launched in 2000 with the introduction of pedagogical experiments aiming at educating youngsters and the general public on weightlessness effects. In November 2000, four secondary school teachers detached to the Euro Space Center (ESC) participated in the 29th ESA campaign. The ESC in Belgium provides recreational and educational activities for the general public and organizes space classes targeted at primary and secondary school pupils. The four teachers performed simple experiments with gyroscopes, yo-yos, magnetic balls, pendulum and food to explain their different behaviour in weightlessness, to show characteristics and possibilities of the microgravity environment and the difficulties that astronauts encounter in their daily life in orbit.

  20. The recurrence interval of great earthquakes along the Sagami trough

    NASA Astrophysics Data System (ADS)

    Ando, M.

    2003-12-01

    Along the Sagami trough, an oblique subuduction zone between the Philippine Sea and North American plates, great earthquakes occurred in 1923 (M7.9) and1703 (M8.6), about 50 km southwest of the Tokyo. Both events generated strong ground motions and tsunamis. Strong ground motions equivalent to seismic intensities 6 to 7 in JMA scale and 10 to 12 in MM scale struck over southern Kanto. The two earthquakes are similar more or less in the extent of the damage and the crustal deformation, possibly occurring very near each other. The extent of the damage and the crustal deformation on the southern area was greater in the 1703 event, whose tsunami reached and damaged the coast of the Kii peninsula, 300 to 400 km away from the source. The source region of the 1703 earthquake, therefore, is considered to have extended towards the ocean and much larger than that of the 1923 event. Several studies of uplift coastal terraces suggest the events like the 1703 one have occurred possibly every 1,000-2,000 years, while those like the 1923 Kanto earthquake more frequently without leaving geomorphic evidence on the terraces. Before 1703, a possible candidate for a subduction event is the M7.0-7.5 1257 or M7.0 1293 earthquake that caused serious damage to southern Kanto region. However, no other earthquakes have been found in historical documents. Historically, the Kanto area was not well civilized until 13th century and earthquakes are not well documented. In addition most historical documents recorded between 14th and 16th centuries were lost during the age of civil wars. If an average recurrence interval is 200 years, at least 4 to 5 events should have occurred before 1703,since the 9th century when the first earthquake was reported in this area. The incomplete earthquake history may contain at least two recurrence intervals, 200 and 400 years. However, the 400 year interval can be shortened by inserting additional earthquakes. For the purposes of hazard mitigation and study of

  1. Hydrothermal Tar Mounds in Escanaba Trough, Southern Gorda Ridge

    NASA Astrophysics Data System (ADS)

    Koski, R. A.; Clague, D. A.; Rosenbauer, R. A.; Hostettler, F. D.; Kvenvolden, K. A.; Lamothe, P. J.

    2002-12-01

    Mounds of asphaltic petroleum were located and sampled by the submersible ROV Tiburon at two sites on the 3300-m-deep, sediment-covered floor of Escanaba Trough, southern Gorda Ridge. The northern site (41.01°N) consists of several individual mounds up to 1 m across and 25 cm high that occur within 100 m of active hydrothermal vents and polymetallic sulfide deposits. These mounds are not covered by sediment and serve as solid substrates for anemones and sponges. Fragments of a partly-buried tar mound at the southern site (40.69°N) were recovered near a field of inactive sulfide deposits. The mounds have a lobate morphology in which younger lobes with lustrous surfaces drape over older lobes encrusted by mud and faunal debris. In cross section, individual lobes have dense rinds, softer inner walls, and hollow cores. Coupled gas chromatography-mass spectrometry analyses of tar samples show the presence of a mixture of aliphatic and aromatic hydrocarbons. The aliphatic fractions have homologous n-alkane distributions from n-C12 to n-C36 with Cmax = n-C28, and a distinctive even-over-odd C-number predominance. Epimer ratios for hopanes and steranes indicate hydrocarbons that are relatively immature. The polycyclic aromatic hydrocarbons (PAH) are dominated by high-molecular-weight parent molecules such as pyrene and phenanthrene; alkylated derivatives are minor constituents. The aromatic fractions also contain a large unresolved complex mixture (UCM). The presence of high-molecular-weight PAH (e.g., benzo-pyrene, indeno-pyrene) reflects formation at high temperatures compared to conventional petroleum. Microwave digestion followed by inductively coupled plasma-mass spectrometry analyses of the soluble organic fraction from three tar samples reveal the following concentrations: 0.1 to 0.2 wt% S, 1 to 10 ppm Mg, Al, P, Cr, Fe, Ni, Cu, Zn, As, Se, and Ba, 1 to 100 ppb Pd and Pt, and 1 to 10 ppb Au. The insoluble residues separated from these samples, analyzed by scanning

  2. Paleocene Pacific Plate reorganization mirrored in formation of the Suvarov Trough, Manihiki Plateau

    NASA Astrophysics Data System (ADS)

    Pietsch, Ricarda; Uenzelmann-Neben, Gabriele

    2016-10-01

    The Suvarov Trough is a graben structure that deviates from the Danger Islands Troughs within the Manihiki Plateau, a Large Igneous Province (LIP) located in the Central Pacific. New high-resolution seismic reflection data provide evidence that the graben formed in two phases during the Paleocene (65-45 Ma). In a first phase extension occurred in southwestward direction, pulling apart the northern part of the Suvarov Trough and a parallel trending unnamed trough. In a second phase a change of extensional force direction occurred from southwest to west-northwest, forming the southern part of the Suvarov Trough that extends onto the High Plateau. The formation of the Suvarov Trough is accompanied by a series of normal fault systems that apparently formed simultaneously. Comparing the seismic results to existing Pacific paleo strain reconstructions, the timing of increased strain and local deformation direction fits well to our findings. We thus suggest that the multiple strike directions of the Suvarov Trough represent an extensional structure that was caused by the major, stepwise Pacific Plate reorganization during the Paleocene.

  3. 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.

  4. 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.

  5. 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.

  6. The O+ Density Trough at 5000 km Altitude in the Polar Cap

    NASA Technical Reports Server (NTRS)

    Zeng, W.; Horowitz, J. L.; Cravens, P. D.; Rich, F. J.; Moore, T. E.

    2003-01-01

    At altitudes near 5000 km over the Southern polar cap region of the terrestrial magnetospherehonosphere, the Thermal Ion Dynamics Experiment (TIDE) onboard the Polar satellite has observed O+ ion density trough regions, in which the O+ densities were at least one order of magnitude lower than the surrounding O+ densities. In the O+ demify trough regions, the estimated O+ densities were generally lower than 0.01 per cc. The boundaries between normal density level regions and the trough density regions were usually abrupt transitions. From December 1, 1997 to November 30, 1998, polar cap O+ troughs in Polar/TIDE observations occurred at a frequency of about 48%. Statistical examination of the Polar perigee observations from December 1 , 1997 to November 30, 1998 shows that the Polar perigee passes evenly covered the southern polar cap region, while the O+ density trough was always located on the nightside portion of the polar cap magnetospherehonosphere, and that invariant latitude spans of such troughs could be as large as 230 in extent. The trough occurrence displayed strong seasonal dependence; in the winter season (e.g. for July in the southern hemisphere) the O+ ion density trough occurrence frequency ranged up to 92%, while in the summer season (e.g. for January in the southern hemisphere) it decreased to as infrequent as 15%. The O+ ion density trough occurrence appeared relatively independent of the geomagnetic Kp index, and IMF Bz, By conditions. However, as suggested by the seasonal dependence, the O+ ion density trough occurrence was strongly related to the solar zenith angle (SZA). In the SZA range 500 to 1250, the trough occurrence increased monotonically with SZA. Also, case-by-case examinations of near-simultaneous O+ densities and vertical velocities observed by the DMSP satellite group orbiting at 840 km altitude indicate that the O+ density troughs observed at 5000 km altitude exhibit moderate correlation or anti-correlation with topside ionosphere

  7. Weak lensing by galaxy troughs with modified gravity

    NASA Astrophysics Data System (ADS)

    Barreira, Alexandre; Bose, Sownak; Li, Baojiu; Llinares, Claudio

    2017-02-01

    We study the imprints that theories of gravity beyond GR can leave on the lensing signal around line of sight directions that are predominantly halo-underdense (called troughs) and halo-overdense. To carry out our investigations, we consider the normal branch of DGP gravity, as well as a phenomenological variant thereof that directly modifies the lensing potential. The predictions of these models are obtained with N-body simulation and ray-tracing methods using the ECOSMOG and Ray-Ramses codes. We analyse the stacked lensing convergence profiles around the underdense and overdense lines of sight, which exhibit, respectively, a suppression and a boost w.r.t. the mean in the field of view. The modifications to gravity in these models strengthen the signal w.r.t. ΛCDM in a scale-independent way. We find that the size of this effect is the same for both underdense and overdense lines of sight, which implies that the density field along the overdense directions on the sky is not sufficiently evolved to trigger the suppression effects of the screening mechanism. These results are robust to variations in the minimum halo mass and redshift ranges used to identify the lines of sight, as well as to different line of sight aperture sizes and criteria for their underdensity and overdensity thresholds.

  8. 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.

  9. Origin and model of transform faults in the Okinawa Trough

    NASA Astrophysics Data System (ADS)

    Liu, Bo; Li, Sanzhong; Jiang, Suhua; Suo, Yanhui; Guo, Lingli; Wang, Yongming; Zhang, Huixuan

    2017-03-01

    Transform faults in back-arc basins are the key to revealing the opening and development of marginal seas. The Okinawa Trough (OT) represents an incipient and active back-arc or marginal sea basin oriented in a general NE-SW direction. To determine the strikes and spatial distribution of transform faults in the OT, this paper dissects the NW- and NNE-SN-trending fault patterns on the basis of seismic profiles, gravity anomalies and region geological data. There are three main NW-trending transpressional faults in the OT, which are the seaward propagation of NW-trending faults in the East China Continent. The NNE-SN-trending faults with right-stepping distribution behave as right-lateral shearing. The strike-slip pull-apart process or transtensional faulting triggered the back-arc rifting or extension, and these faults evolved into transform faults with the emergence of oceanic crust. Thus, the transform fault patterns are inherited from pre-existing oblique transtensional faults at the offsets between rifting segments. Therefore, the OT performs the oblique spreading mechanism similar to nascent oceans such as the Red Sea and Gulf of Aden.

  10. 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.

  11. Sill genesis in the Paleoproterozoic tectonic evolution of the Onega Trough, Baltic shield

    NASA Astrophysics Data System (ADS)

    Poleshchuk, A. V.

    2011-07-01

    This study considers the role of sill genesis in the tectonic evolution of the Onega Trough during the Middle to Late Paleoproterozoic (Jatulian-Vepsian). The evolution of the Onega Trough is divided into three stages: pre-sill, or preparatory, subsynchronous, and post-sill. Sill magmatism manifested itself most completely at the subsynchronous stage of the evolution of the Onega Trough within the initial, principal, and final phases of sill genesis. Sill formation followed the stage of regional downwarping of the area reaching its maximum during the Early Ludicovian. Paragenesis of sills and high carbon shungite rocks was accompanied by the formation of peperites, while sills influenced the structure of the host rocks. A model reflecting the regular patterns of manifestations of sill genesis identified in the Onega Trough has been proposed.

  12. 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

  13. Evaluation of the relationship between elevated vancomycin trough concentrations and increased efficacy and/or toxicity.

    PubMed

    Ackerman, Bruce H; Guilday, Robert E; Reigart, Cynthia L; Patton, Mary L; Haith, Linwood R

    2013-01-01

    Isolation of Staphylococcus aureus with minimum inhibitory concentrations, 1 to 2 mg/L, suggests increasing vancomycin trough ranges, from 10 to 20 mg/L or even higher. Vancomycin troughs from 604 treatment courses from 560 patients with suspected or actual Gram-positive infection were analyzed with focus on potential toxicity/efficacy. Trough concentrations were required to be drawn within 15 to 45 minutes before the administration of at least the third vancomycin dose. Patients were retrospectively evaluated for their total daily dose and milligrams per kilograms per vancomycin dose. Data on the duration of vancomycin therapy, days to a normal temperature, and white blood cells were obtained. Data were stratified by trough concentration as <5, 5 to 10, and >10 mg/L to determine whether there was any relationship between response and trough concentration. Demographic data were obtained in 560 patients with 604 vancomycin treatment courses. For 361 patients with 379 separate treatment courses of vancomycin therapy no other nephrotoxic antimicrobial agent had been used. The greatest risk of vancomycin nephrotoxicity correlated with the duration of treatment. Using the log time to normal temperature, white blood cell count, heart rate, outcome from vancomycin therapy was assessed and no relationship could be demonstrated for the three vancomycin trough strata using analysis of variance (F < 2.62 for all parameters; p > .05). These data indicate that vancomycin trough elevation may not guarantee treatment success and that there may be no real benefit from higher vancomycin trough concentrations in thermal injury patients with burns <20% TBSA.

  14. 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

  15. 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.

  16. Constraints upon water advection in sediments of the Mariana Trough

    SciTech Connect

    Abbott, D.H.; Menke, W.; Morin, R.

    1983-02-10

    Thermal gradient measurements, consolidation tests, and pore water compositions from the Mariana Trough imply that water is moving through the sediments in areas with less than about 100 m of sediment cover. The maximum advection rates implied by the thermal measurements and consolidation tests may be as high as 10/sup -5/ cm s/sup -1/ but are most commonly in the range of 1 to 5 x 10/sup -6/ cm s/sup -1/. Theoretical calculations of the effect of the highest advection rates upon carbonate dissolution indicate that dissolution may be impeded or enhanced (depending upon the direction of flow) by a factor of 2 to 5 times the rate for diffusion alone. The average percentage of carbonate is consistently higher in two cores from the area with no advection or upward advection than the average percentage of carbonate in three cores from the area with downward advection. This increase in average amount of carbonate in cores with upward moving water or no movement cannot be attributed solely to differences in water depth or in amount of terrigenous dilution. If the sediment column acts as a passive boundary layer, then the water velocities necessary to affect chemical gradients of silica are in the range 10/sup -9/ to 10/sup -10/ cm s/sup -1/. However, if dissolution of silica occurs within the sediment column, then the advection velocities needed to affect chemical gradients are at least 3 x 10/sup -8/ cm s/sup -1/ and may be as high as 3 x 10/sup -6/ cm s/sup -1/. This order of magnitude increase in advection velocities when chemical reactions occur within the sediments is probably applicable to other cations in addition to silica. If so, then the advection velocities needed to affect heat flow (>10/sup -8/ cm s/sup -1/) and pore water chemical gradients are much nearer in magnitude than previously assumed.

  17. Onset and migration of spiral troughs on Mars revealed by orbital radar.

    PubMed

    Smith, Isaac B; Holt, John W

    2010-05-27

    The landscape of the north polar layered deposits of Mars (NPLD) is dominated by a pinwheel array of enigmatic spiral troughs. The troughs have intrigued planetary scientists since the Mariner 9 spacecraft returned the first close-up image in 1972, but conclusive evidence of their origin has remained elusive. Debate continues regarding all aspects of the troughs, including the possibility that they have migrated, their age in relation to the current NPLD surface, and whether they are fundamentally erosional or constructional features. The troughs are probably related to climatic processes, yet the nature of this relationship has remained a mystery. Previous data characterizing only the exposed NLPD surface were insufficient to test these hypotheses. Here we show that the central spiral troughs initiated after deposition of three-quarters of the NPLD, quickly reached a stable morphology and migrated approximately 65 kilometres poleward and 600 metres in altitude over the past two million years or so. Our radar stratigraphy rules out hypotheses of erosional incision post-dating deposition, and instead largely validates an early hypothesis for constructional trough migration with wind transport and atmospheric deposition as dominant processes. These results provide hard constraints for palaeo-climate models and a new context for evaluating imagery, spectral data, and now radar sounding data, the better to understand the link between orbital parameters and climate, the role of climate in shaping the polar ice of Mars, and eventually, the age of the polar deposits themselves.

  18. 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.

  19. 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.

  20. Valles Marineris, Mars: Are pit chains formed by erosion and troughs by tectonism?

    NASA Technical Reports Server (NTRS)

    Lucchitta, Baerbel K.; Balser, R. A.; Bertolini, L. M.

    1991-01-01

    The origin of the Valles Marineris remains controversial. Erosional, tectonic, and hybrid processes have been proposed. To clarify these contradictions, the widths and depths of pit chains and troughs were compared and it was found that the features do not form a continuum. Rather, results are consistent with the hypothesis that pit chains formed by surficial collapse and troughs by deeper seated and coherent failure. All pit chains and linear depressions in the Valles Marineris region were classified by inspection into six morphologic categories: pit chains (linear arrays of small pits); floored chains (arrays of pit chains having flat or hummocky floors); scalloped troughs (wider linear depressions with scalloped wall segments); narrow troughs (depressions of intermediate width with straight wall segments); wide troughs (broad, linear depressions); and chaotic troughs (more irregular depressions displaying some channel morphologies). Topographic profiles were drawn across the classified depressions and the erosional width was determined between plateau margins along with the depth from the surrounding plateau level to the deepest part.

  1. 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.

  2. Decadal variation of the Northern Hemisphere Annular Mode and its influence on the East Asian trough

    NASA Astrophysics Data System (ADS)

    Lu, Chunhui; Zhou, Botao; Ding, Yihui

    2016-06-01

    We analyze the decadal variation of the stratosphere-troposphere coupled system around the year 2000 by using the NCEP reanalysis-2 data. Specifically, the relationship between the Northern Hemisphere Annular Mode (NAM) and the tropospheric East Asian trough is investigated in order to find the effective stratospheric signals during cold air outbreaks in China. Statistical analyses and dynamic diagnoses both indicate that after 2000, increased stratospheric polar vortex disturbances occur and the NAM is mainly in negative phase. The tropospheric polar areas are directly affected by the polar vortex, and in the midlatitudes, the Ural blocking high and East Asian trough are more active, which lead to enhanced cold air activities in eastern and northern China. Further investigation reveals that under this circulation pattern, downward propagations of negative NAM index are closely related to the intensity variation of the East Asian trough. When negative NAM anomalies propagate down to the upper troposphere and reach a certain intensity (standardized NAM index less than-1), they result in apparent reinforcement of the East Asian trough, which reaches its maximum intensity about one week later. The northerly wind behind the trough transports cold air southward and eastward, and the range of influence and the intensity are closely associated with the trough location. Therefore, the NAM index can be used as a measure of the signals from the disturbed stratosphere to give some indication of cold air activities in China.

  3. Error Analysis for Discontinuous Galerkin Method for Parabolic Problems

    NASA Technical Reports Server (NTRS)

    Kaneko, Hideaki

    2004-01-01

    In the proposal, the following three objectives are stated: (1) A p-version of the discontinuous Galerkin method for a one dimensional parabolic problem will be established. It should be recalled that the h-version in space was used for the discontinuous Galerkin method. An a priori error estimate as well as a posteriori estimate of this p-finite element discontinuous Galerkin method will be given. (2) The parameter alpha that describes the behavior double vertical line u(sub t)(t) double vertical line 2 was computed exactly. This was made feasible because of the explicitly specified initial condition. For practical heat transfer problems, the initial condition may have to be approximated. Also, if the parabolic problem is proposed on a multi-dimensional region, the parameter alpha, for most cases, would be difficult to compute exactly even in the case that the initial condition is known exactly. The second objective of this proposed research is to establish a method to estimate this parameter. This will be done by computing two discontinuous Galerkin approximate solutions at two different time steps starting from the initial time and use them to derive alpha. (3) The third objective is to consider the heat transfer problem over a two dimensional thin plate. The technique developed by Vogelius and Babuska will be used to establish a discontinuous Galerkin method in which the p-element will be used for through thickness approximation. This h-p finite element approach, that results in a dimensional reduction method, was used for elliptic problems, but the application appears new for the parabolic problem. The dimension reduction method will be discussed together with the time discretization method.

  4. 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.

  5. 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.

  6. Limits of Femtosecond Fiber Amplification by Parabolic Pre-Shaping

    PubMed Central

    Fu, Walter; Tang, Yuxing; McComb, Timothy S.; Lowder, Tyson L.; Wise, Frank W.

    2017-01-01

    We explore parabolic pre-shaping as a means of generating and amplifying ultrashort pulses. We develop a theoretical framework for modeling the technique and use its conclusions to design a femtosecond fiber amplifier. Starting from 9 ps pulses, we obtain 4.3 μJ, nearly transform-limited pulses 275 fs in duration, simultaneously achieving over 40 dB gain and 33-fold compression. Finally, we show that this amplification scheme is limited by Raman scattering, and outline a method by which the pulse duration and energy may be further improved and tailored for a given application. PMID:28331242

  7. Upper bounds for parabolic equations and the Landau equation

    NASA Astrophysics Data System (ADS)

    Silvestre, Luis

    2017-02-01

    We consider a parabolic equation in nondivergence form, defined in the full space [ 0 , ∞) ×Rd, with a power nonlinearity as the right-hand side. We obtain an upper bound for the solution in terms of a weighted control in Lp. This upper bound is applied to the homogeneous Landau equation with moderately soft potentials. We obtain an estimate in L∞ (Rd) for the solution of the Landau equation, for positive time, which depends only on the mass, energy and entropy of the initial data.

  8. 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.

  9. Parabolized Navier-Stokes methods for hypersonic flows

    NASA Technical Reports Server (NTRS)

    Lawrence, Scott L.

    1991-01-01

    A representative sampling of the techniques used in the integration of the Parabolized Navier-Stokes (PNS) equations is presented. Special atention is given to recent algorithms developed specifically for application to high speed flows, characterized by the presence of strong embedded shock waves and real gas effects. It is shown that PNS solvers are being used in the analysis of sonic boom signatures. Methods for modeling physical effects are discussed, including an overview of commonly used turbulence models and a more detailed discussion of techniques for including equilibrium and finite rate real gas effects.

  10. PE Workshop II. Proceedings of the Second Parabolic Equation Workshop

    DTIC Science & Technology

    1993-01-01

    pp. 21-28. [11 ] M. D. Feit and J. A. Fleck, Jr., "Computation of mode properties in optical fiber waveguides by a propagating beam method," Appl...that are, at best, only typical of that region of the worlds oceans. Ocean bottom properties obtained from historical data bases are usually less...the first term of a geometric- optical series," Comm. Pure and Appl. Math. 4, 105-115. Brock, H. K. (1975). "The AESD parabolic equation model," AESD TN

  11. Dynamics of parabolic problems with memory. Subcritical and critical nonlinearities

    NASA Astrophysics Data System (ADS)

    Li, Xiaojun

    2016-08-01

    In this paper, we study the long-time behavior of the solutions of non-autonomous parabolic equations with memory in cases when the nonlinear term satisfies subcritical and critical growth conditions. In order to do this, we show that the family of processes associated to original systems with heat source f(x, t) being translation bounded in Lloc 2 ( R ; L 2 ( Ω ) ) is dissipative in higher energy space M α , 0 < α ≤ 1, and possesses a compact uniform attractor in M 0 .

  12. Fuzzy control of parabolic antenna with backlash compensation

    NASA Astrophysics Data System (ADS)

    Ahmed, Mohammed; Noor, Samsul Bahari B. Mohd

    2015-05-01

    A fuzzy logic based controller (FLC) was proposed for position control of a parabolic dish antenna system with the major aim of eradicating the effect backlash disturbance which may be present in the system. The disturbance is nonlinear and is capable of generating steady state positional errors. Simulation results obtained using SIMULINK/MATLAB 2012a were compared with those obtained when the controller was proportional-derivative controller (PDC). The fuzzy controller portrays that it has the capability of reducing the noise due to backlash and possibly others more than the proportional-derivative controller.

  13. Galerkin/Runge-Kutta discretizations of nonlinear parabolic equations

    NASA Astrophysics Data System (ADS)

    Hansen, Eskil

    2007-08-01

    Global error bounds are derived for full Galerkin/Runge-Kutta discretizations of nonlinear parabolic problems, including the evolution governed by the p-Laplacian with p[greater-or-equal, slanted]2. The analysis presented here is not based on linearization procedures, but on the fully nonlinear framework of logarithmic Lipschitz constants and an extended B-convergence theory. The global error is bounded in L2 by [Delta]xr/2+[Delta]tq, where r is the convergence order of the Galerkin method applied to the underlying stationary problem and q is the stiff order of the algebraically stable Runge-Kutta method.

  14. Spectral Deferred Corrections for Parabolic Partial Differential Equations

    DTIC Science & Technology

    2015-06-08

    linear differential equation ϕ′(t) = λϕ(t), t ≥ 0 ϕ(0) = 1, (3.31) where λ ∈ C, has exact solution ϕ(t) = eλt. (3.32) Traditionally, for a fixed time step...the second-order differentiation matrix with 16 subintervals and 16 points per subinterval. From Figure 5.2, this matrix approximates the exact ...We describe a new class of algorithms for the solution of parabolic partial differential equa- tions (PDEs). This class of schemes is based on three

  15. Scattering Parabolic Solutions for the Spatial N-Centre Problem

    NASA Astrophysics Data System (ADS)

    Boscaggin, Alberto; Dambrosio, Walter; Terracini, Susanna

    2017-03-01

    For the N-centre problem in the three dimensional space, {ddot{x}} = -sum_{i=1}N m_i (x-c_i)/\\vert x - c_i \\vert^{α+2}, qquad x in R^3 {setminus} {c_1,ldots,c_N}, where {N ≥q 2}, {m_i > 0} and {α in [1,2)}, we prove the existence of entire parabolic trajectories having prescribed asymptotic directions. The proof relies on a variational argument of min-max type. Morse index estimates and regularization techniques are used in order to rule out the possible occurrence of collisions.

  16. Vancomycin AUC/MIC and Corresponding Troughs in a Pediatric Population

    PubMed Central

    Lardieri, Allison B.; Heil, Emily L.; Morgan, Jill A.

    2017-01-01

    OBJECTIVES Adult guidelines suggest an area under the curve/minimum inhibitory concentration (AUC/MIC) > 400 corresponds to a vancomycin trough serum concentration of 15 to 20 mg/L for methicillin-resistant Staphylococcus aureus infections, but obtaining these troughs in children are difficult. The primary objective of this study was to assess the likelihood that 15 mg/kg of vancomycin every 6 hours in a child achieves an AUC/MIC > 400. METHODS This retrospective chart review included pediatric patients >2 months to <18 years with a positive S aureus blood culture and documented MIC who received at least two doses of vancomycin with corresponding trough. Patients were divided into two groups: group 1 initially receiving ≥15 mg/kg every 6 hours, and group 2 initially receiving any other dosing ranges or intervals. AUCs were calculated four times using three pharmacokinetic methods. RESULTS A total of 36 patients with 99 vancomycin trough serum concentrations were assessed. Baseline characteristics were similar between groups. For troughs in group 1 (n = 55), the probability of achieving an AUC/MIC > 400 ranged from 16.4% to 90.9% with a median trough concentration of 11.4 mg/L, while in group 2 (n = 44) the probability of achieving AUC/MIC > 400 ranged from 15.9% to 54.5% with mean trough concentration of 9.2 mg/L. The AUC/MICs were not similar between the different pharmacokinetic methods used; however, a trapezoidal equation (Method A) yielded the highest correlation coefficient (r2 = 0.59). When dosing every 6 hours, an AUC/MIC of 400 correlated to a trough serum concentration of 11 mg/L. CONCLUSIONS The probability of achieving an AUC/MIC > 400 using only a trough serum concentration and an MIC with patients receiving 15 mg/kg every 6 hours is variable based on the method used to calculate the AUC. An AUC/MIC of 400 in children correlated to a trough concentration of 11 mg/L using a trapezoidal Method to calculate AUC.

  17. The Ordovician Sebree Trough: An oceanic passage to the Midcontinent United States

    USGS Publications Warehouse

    Kolata, Dennis R.; Huff, W.D.; Bergstrom, Stig M.

    2001-01-01

    The Sebree Trough is a relatively narrow, shale-filled sedimentary feature extending for several hundred kilometers across the Middle and Late Ordovician carbonate platform of the Midcontinent United States. The dark graptolitic shales within the trough stand in contrast to the coeval bryozoan-brachiopod-echinodermrich limestones on the flanking platforms. We infer from regional stratal patterns, thickness and facies trends, and temporal relations established by biostratigraphy and K-bentonite stratigraphy that the Sebree Trough initially began to develop during late Turinian to early Chatfieldian time (Mohawkian Series) as a linear bathymetric depression situated over the failed late Precambrian-Early Cambrian Reelfoot Rift. Rising sea level and positioning of a subtropical convergence zone along the southern margin of Laurentia caused the rift depression to descend into cool, oxygen-poor, phosphate-rich oceanic waters that entered the southern reaches of the rift from the Iapetus Ocean. The trough apparently formed in a system of epicontinental estuarine circulation marked by a density-stratified water column. Trough formation was accompanied by cessation of carbonate sedimentation, deposition of graptolitic shales, development of hardground omission surfaces, substrate erosion, and local phosphogenesis. The carbonate platforms on either side of the trough are dominated by bryozoan-brachiopod-echinoderm grainstones and packstones that were deposited in zones of mixing where cool, nutrient-rich waters encountered warmer shelf waters. Concurrently, lime mudstone and wackestone were deposited shoreward (northern Illinois, Wisconsin, Iowa, Minnesota, Michigan) in warmer, more tropical shallow seas. Coeval upward growth of the flanking carbonate platforms sustained and enhanced development of the trough shale facies. Five widespread diachronous late Mohawkian and Cincinnatian omission surfaces are present in the carbonate facies of the Midcontinent. These surfaces

  18. 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.

  19. 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.

  20. 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.

  1. Symmetries and pattern formation in hyperbolic versus parabolic models of self-organised aggregation.

    PubMed

    Buono, Pietro-Luciano; Eftimie, Raluca

    2015-10-01

    The study of self-organised collective animal behaviour, such as swarms of insects or schools of fish, has become over the last decade a very active research area in mathematical biology. Parabolic and hyperbolic models have been used intensively to describe the formation and movement of various aggregative behaviours. While both types of models can exhibit aggregation-type patterns, studies on hyperbolic models suggest that these models can display a larger variety of spatial and spatio-temporal patterns compared to their parabolic counterparts. Here we use stability, symmetry and bifurcation theory to investigate this observation more rigorously, an approach not attempted before to compare and contrast aggregation patterns in models for collective animal behaviors. To this end, we consider a class of nonlocal hyperbolic models for self-organised aggregations that incorporate various inter-individual communication mechanisms, and take the formal parabolic limit to transform them into nonlocal parabolic models. We then discuss the symmetry of these nonlocal hyperbolic and parabolic models, and the types of bifurcations present or lost when taking the parabolic limit. We show that the parabolic limit leads to a homogenisation of the inter-individual communication, and to a loss of bifurcation dynamics (in particular loss of Hopf bifurcations). This explains the less rich patterns exhibited by the nonlocal parabolic models. However, for multiple interacting populations, by breaking the population interchange symmetry of the model, one can preserve the Hopf bifurcations that lead to the formation of complex spatio-temporal patterns that describe moving aggregations.

  2. 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),

  3. Altered osteoblast structure and function in parabolic flight

    NASA Astrophysics Data System (ADS)

    Zhong-Quan, Dai; Ying-Hui, Li; Fen, Yang; Bai, Ding; Ying-Jun, Tan

    Introduction Bone loss has a significant impact on astronauts during spaceflight being one of the main obstacles preventing interplanetary missions However the exact mechanism is not well understood In the present study we investigated the effects of acute gravitational changes generated by parabolic flight on the structure and function of osteoblasts ROS17 2 8 carried by airbus A300 Methods The alteration of microfilament cytoskeleton was observed by the Texas red conjugated Phalloidin and Alexa Fluor 488 conjugated DNase I immunofluorescence stain ALP activity and expression COL1A1 expression osteocalcin secrete which presenting the osteoblast function were detected by modified calcium and cobalt method RT-PCR and radioimmunity methods respectively Results The changed gravity induced the reorganization of microfilament cytoskeleton of osteoblast After 3 hours parabolic flight F-actin of osteoblast cytoskeleton became more thickness and directivity whereas G-actin reduced and relatively concentrated at the edge of nucleus observed by confocal fluorescence microscopy This phenomenon is identical with structure alternation observed in hypergravity but the osteoblast function decrease The excretion of osteocalcin the activity and mRNA expression of ALP decrease but the COL1A1 expression has no changes These results were similar to the changes in simulated or real microgravity Conclusion Above results suggest that short time gravity alternative change induce osteoblast structure and function

  4. Experimental testing of the variable rotated elastic parabolic equation.

    PubMed

    Simpson, Harry J; Collis, Jon M; Soukup, Raymond J; Collins, Michael D; Siegmann, William L

    2011-11-01

    A series of laboratory experiments was conducted to obtain high-quality data for acoustic propagation in shallow water waveguides with sloping elastic bottoms. Accurate modeling of transmission loss in these waveguides can be performed with the variable rotated parabolic equation method. Results from an earlier experiment with a flat or sloped slab of polyvinyl chloride (PVC) demonstrated the necessity of accounting for elasticity in the bottom and the ability of the model to produce benchmark-quality agreement with experimental data [J. M. Collis et al., J. Acoust. Soc. Am. 122, 1987-1993 (2007)]. This paper presents results of a second experiment, using two PVC slabs joined at an angle to create a waveguide with variable bottom slope. Acoustic transmissions over the 100-300 kHz band were received on synthetic horizontal arrays for two source positions. The PVC slabs were oriented to produce three different simulated waveguides: flat bottom followed by downslope, upslope followed by flat bottom, and upslope followed by downslope. Parabolic equation solutions for treating variable slopes are benchmarked against the data.

  5. 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.

  6. Innovative design of parabolic reflector light guiding structure

    NASA Astrophysics Data System (ADS)

    Whang, Allen J.; Tso, Chun-Hsien; Chen, Yi-Yung

    2008-02-01

    Due to the idea of everlasting green architecture, it is of increasing importance to guild natural light into indoors. The advantages are multifold - to have better color rendering index, excellent energy savings from environments viewpoints and make humans more healthy, etc. Our search is to design an innovative structure, to convert outdoor sun light impinges on larger surfaces, into near linear light beam sources, later convert this light beam into near point sources which enters the indoor spaces then can be used as lighting sources indoors. We are not involved with the opto-electrical transformation, to the guild light into to the building, to perform the illumination, as well as the imaging function. Because non-imaging optics, well known for apply to the solar concentrators, that can use non-imaging structures to fulfill our needs, which can also be used as energy collectors in solar energy devices. Here, we have designed a pair of large and small parabolic reflector, which can be used to collect daylight and change area from large to small. Then we make a light-guide system that is been designed by us use of this parabolic reflector to guide the collection light, can pick up the performance for large surface source change to near linear source and a larger collection area.

  7. A parabolic velocity-decomposition method for wind turbines

    NASA Astrophysics Data System (ADS)

    Mittal, Anshul; Briley, W. Roger; Sreenivas, Kidambi; Taylor, Lafayette K.

    2017-02-01

    An economical parabolized Navier-Stokes approximation for steady incompressible flow is combined with a compatible wind turbine model to simulate wind turbine flows, both upstream of the turbine and in downstream wake regions. The inviscid parabolizing approximation is based on a Helmholtz decomposition of the secondary velocity vector and physical order-of-magnitude estimates, rather than an axial pressure gradient approximation. The wind turbine is modeled by distributed source-term forces incorporating time-averaged aerodynamic forces generated by a blade-element momentum turbine model. A solution algorithm is given whose dependent variables are streamwise velocity, streamwise vorticity, and pressure, with secondary velocity determined by two-dimensional scalar and vector potentials. In addition to laminar and turbulent boundary-layer test cases, solutions for a streamwise vortex-convection test problem are assessed by mesh refinement and comparison with Navier-Stokes solutions using the same grid. Computed results for a single turbine and a three-turbine array are presented using the NREL offshore 5-MW baseline wind turbine. These are also compared with an unsteady Reynolds-averaged Navier-Stokes solution computed with full rotor resolution. On balance, the agreement in turbine wake predictions for these test cases is very encouraging given the substantial differences in physical modeling fidelity and computer resources required.

  8. Positive solutions of quasilinear parabolic systems with nonlinear boundary conditions

    NASA Astrophysics Data System (ADS)

    Pao, C. V.; Ruan, W. H.

    2007-09-01

    The aim of this paper is to investigate the existence, uniqueness, and asymptotic behavior of solutions for a coupled system of quasilinear parabolic equations under nonlinear boundary conditions, including a system of quasilinear parabolic and ordinary differential equations. Also investigated is the existence of positive maximal and minimal solutions of the corresponding quasilinear elliptic system as well as the uniqueness of a positive steady-state solution. The elliptic operators in both systems are allowed to be degenerate in the sense that the density-dependent diffusion coefficients Di(ui) may have the property Di(0)=0 for some or all i. Our approach to the problem is by the method of upper and lower solutions and its associated monotone iterations. It is shown that the time-dependent solution converges to the maximal solution for one class of initial functions and it converges to the minimal solution for another class of initial functions; and if the maximal and minimal solutions coincide then the steady-state solution is unique and the time-dependent solution converges to the unique solution. Applications of these results are given to three model problems, including a porous medium type of problem, a heat-transfer problem, and a two-component competition model in ecology. These applications illustrate some very interesting distinctive behavior of the time-dependent solutions between density-independent and density-dependent diffusions.

  9. Positive solutions of quasilinear parabolic systems with Dirichlet boundary condition

    NASA Astrophysics Data System (ADS)

    Pao, C. V.; Ruan, W. H.

    Coupled systems for a class of quasilinear parabolic equations and the corresponding elliptic systems, including systems of parabolic and ordinary differential equations are investigated. The aim of this paper is to show the existence, uniqueness, and asymptotic behavior of time-dependent solutions. Also investigated is the existence of positive maximal and minimal solutions of the corresponding quasilinear elliptic system. The elliptic operators in both systems are allowed to be degenerate in the sense that the density-dependent diffusion coefficients D(u) may have the property D(0)=0 for some or all i=1,…,N, and the boundary condition is u=0. Using the method of upper and lower solutions, we show that a unique global classical time-dependent solution exists and converges to the maximal solution for one class of initial functions and it converges to the minimal solution for another class of initial functions; and if the maximal and minimal solutions coincide then the steady-state solution is unique and the time-dependent solution converges to the unique solution. Applications of these results are given to three model problems, including a scalar polynomial growth problem, a coupled system of polynomial growth problem, and a two component competition model in ecology.

  10. Wave variance partitioning in the trough of a barred beach

    NASA Astrophysics Data System (ADS)

    Howd, Peter A.; Oltman-Shay, Joan; Holman, Robert A.

    1991-07-01

    The wave-induced velocity field in the nearshore is composed of contributions from incident wind waves (ƒ > 0.05 Hz), surface infragravity waves (ƒ < 0.05 Hz, |κ| < (σ2/gβ) and shear waves (ƒ < 0.05 Hz, |κ| > σ2/gβ), where ƒ is the frequency, σ = 2πƒ, κ is the radial alongshore wavenumber (2π/L, L being the alongshore wavelength), β is the beach slope, and g is the acceleration due to gravity. Using an alongshore array of current meters located in the trough of a nearshore bar (mean depth ≈ 1.5 m), we investigate the bulk statistical behaviors of these wave bands over a wide range of incident wave conditions. The behavior of each contributing wave type is parameterized in terms of commonly measured or easily predicted variables describing the beach profile, wind waves, and current field. Over the 10-day period, the mean contributions (to the total variance) of the incident, infragravity, and shear wave bands were 71.5%, 14.3% and 13.6% for the alongshore component of flow (mean rms oscillations of 44, 20, and 19 cm s-1, respectively), and 81.9%, 10.9%, and 6.6% for the cross-shore component (mean rms oscillations of 92, 32, and 25 cm s-1, respectively). However, the values varied considerably. The contribution to the alongshore (cross-shore) component of flow ranged from 44.8-88.4% (58.5-95.8%) for the incident band, to 6.2-26.6% (2.5-32.4%) for the infragravity band, and 3.4-33.1% (0.6-14.3%) for the shear wave band. Incident wave oscillations were limited by depth-dependent saturation over the adjacent bar crest and varied only with the tide. The infragravity wave rms oscillations on this barred beach are best parameterized by the offshore wave height, consistent with previous studies on planar beaches. Comparison with data from four other beaches of widely differing geometries shows the shoreline infragravity amplitude to be a near-constant ratio of the offshore wave height. The magnitude of the ratio is found to be dependent on the Iribarren

  11. 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.

  12. 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

  13. Association between vancomycin trough concentration and area under the concentration-time curve in neonates.

    PubMed

    Frymoyer, Adam; Hersh, Adam L; El-Komy, Mohammed H; Gaskari, Shabnam; Su, Felice; Drover, David R; Van Meurs, Krisa

    2014-11-01

    National treatment guidelines for invasive methicillin-resistant Staphylococcus aureus (MRSA) infections recommend targeting a vancomycin 24-h area under the concentration-time curve (AUC0-24)-to-MIC ratio of >400. The range of vancomycin trough concentrations that best predicts an AUC0-24 of >400 in neonates is not known. This understanding would help clarify target trough concentrations in neonates when treating MRSA. A retrospective chart review from a level III neonatal intensive care unit was performed to identify neonates treated with vancomycin over a 5-year period. Vancomycin concentrations and clinical covariates were utilized to develop a one-compartment population pharmacokinetic model and examine the relationships between trough and AUC0-24 in the study neonates. Monte Carlo simulations were performed to examine the effect of dose, postmenstrual age (PMA), and serum creatinine level on trough and AUC0-24 achievement. A total of 1,702 vancomycin concentrations from 249 neonates were available for analysis. The median (interquartile range) PMA was 39 weeks (32 to 42 weeks) and weight was 2.9 kg (1.6 to 3.7 kg). Vancomycin clearance was predicted by weight, PMA, and serum creatinine level. At a trough of 10 mg/liter, 89% of the study neonates had an AUC0-24 of >400. Monte Carlo simulations demonstrated that troughs ranging from 7 to 11 mg/liter were highly predictive of an AUC0-24 of >400 across a range of PMA, serum creatinine levels, and vancomycin doses. However, a trough of ≥10 mg/liter was not readily achieved in most simulated subgroups using routine starting doses. Higher starting doses frequently resulted in troughs of >20 mg/liter. A vancomycin trough of ∼10 mg/liter is likely adequate for most neonates with invasive MRSA infections based on considerations of the AUC0-24. Due to pharmacokinetic and clinical heterogeneity in neonates, consistently achieving this target vancomycin exposure with routine starting doses is difficult. More robust

  14. 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.

  15. 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.

  16. Formation of the equatorial thermosphere anomaly trough: Local time and solar cycle variations

    NASA Astrophysics Data System (ADS)

    Hsu, Vicki W.; Thayer, Jeffrey P.; Lei, Jiuhou; Wang, Wenbin

    2014-12-01

    This paper evaluates the formation and behavior of the equatorial thermosphere anomaly (ETA) trough in neutral temperature and mass density using the National Center for Atmospheric Research thermosphere-ionosphere electrodynamics general circulation model under quiet geomagnetic activity and March equinox conditions. The driving mechanism for the generation of the ETA trough in the model is field-aligned ion drag. In our simulations, during the daytime, field-aligned ion drag on the north-south flanks of the magnetic equator causes a divergence in meridional winds, leading to an upward change in vertical winds, adiabatic cooling, and a reduction in neutral temperature of about 30 K over the magnetic equator near 400 km. This response closely links ETA behavior to variations in the equatorial ionosphere anomaly (EIA) associated with local time and solar cycle. As the EIA begins to disappear in the evening, the processes in the ETA mechanism recede, causing the ETA trough to subside. The ETA trough is not completely eliminated until about after 23:00 LT. In our simulations, the trough becomes more prominent as the solar cycle progresses from low (F10.7=80) to high (F10.7=180), in agreement with observations. The neutral-ion collision frequency (proportional to variations in electron density) controls ETA day-to-night and solar cycle variations, while plasma scale height and gradients in electron number density and plasma temperature produce a secondary structure in ETA local time behavior that varies with solar cycle levels.

  17. Marine sediments in Disko Trough reveal meltwater-influenced sedimentation during ice-stream retreat

    NASA Astrophysics Data System (ADS)

    Hogan, Kelly A.; Cofaigh, Colm Ó.; Jennings, Anne E.; Dowdeswell, Julian A.

    2015-04-01

    Marine geophysical data from middle and outer Disko Trough, West Greenland reveal thick (more than ten metres) acoustically-laminated, fine-grained sediments between subglacial tills at their base and post-glacial marine sediments at the seafloor. These sediments are interpreted as a transitional facies deposited as ice retreated from the trough during deglaciation. New sediment-core records indicate that these units were likely deposited by meltwater plumes emanating from a nearby grounded-ice margin, probably during stillstands in ice retreat. The retreat of ice in the trough may have been stabilised at a narrowing in DiskoTrough on the mid-shelf, as well as at the basalt escarpment south of Disko Island. Such thicknesses of deglacial or "transitional" glacimarine sediments are relatively unusual on high-latitude continental shelves and indicate a significant meltwater production in central West Greenland during deglaciation. This is consistent with the seafloor landforms in the inner and middle parts of the trough that include channels and moats around bedrock protrusions that look to have been eroded by water. IRD counts from the cores indicate that iceberg rafting also occurred during this transitional phase but that this signal was diluted by the fine-grained transitional sediments. Once ice had withdrawn from the area and sedimentation was hemipelagic in nature the IRD signal was less diluted.

  18. Design requirements for interfaces in solar energy conversion technologies

    NASA Astrophysics Data System (ADS)

    Butler, B. L.

    1982-04-01

    Candidate materials for improving the durability and economics of solar energy conversion systems (SECS) are reviewed. A 30-yr lifetime is regarded as necessary for solar collector and concentrator materials in order to offset the high initial costs of SECS in parabolic dish, heliostat, parabolic trough, flat plate collector, OTEC, solar cell, and wind turbine configurations. The materials are required to transfer a maximum amount of intercepted energy without degrading from exposure to UV radiation, wind, water, dust, and temperature cycling. Glass and mirrored surfaces for reflecting or refracting optical subsystems are currently made from soda-lime, boro- and aluminosilicate, and must resist chemicals, abrasion, and permeability, and have good strength, flexibility, coefficient of expansion, and Young's modulus. Additional concerns are present in photochemical, solar cell, and in substrata components and systems.

  19. Technology

    ERIC Educational Resources Information Center

    Isman, Aytekin

    2003-01-01

    This article begins by drawing on literature to examine the various definitions of "technology" and "technique." Following a discussion of the origin of technology in education, the remaining sections of the article focus on the relationships and interaction between: (1) machines and technique; (2) science and technique; (3)…

  20. Technology.

    ERIC Educational Resources Information Center

    Giorgis, Cyndi; Johnson, Nancy J.

    2002-01-01

    Presents annotations of 30 works of children's literature that support the topic of technology and its influences on readers' daily lives. Notes some stories tell about a time when simple tools enabled individuals to accomplish tasks, and others feature visionaries who used technology to create buildings, bridges, roads, and inventions. Considers…

  1. 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.

  2. Performance of a solar-thermal collector

    NASA Technical Reports Server (NTRS)

    Higa, W. H.

    1975-01-01

    Possible means of achieving the technology required for field application of solar thermal power systems are discussed. Simplifications in construction techniques as well as in measurement techniques for parabolic trough collectors are described. Actual measurement data is also given.

  3. 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

  4. Statistical analysis of the mid-latitude trough position during different categories of magnetic storms and different storm intensities

    NASA Astrophysics Data System (ADS)

    Yang, Na; Le, Huijun; Liu, Libo

    2016-11-01

    The ionospheric mid-latitude trough minimum position as a function of geomagnetic storm time is identified and investigated statistically in terms of the category and the intensity of storms. The data of ion density derived from DMSP and DEMETER satellites were used to extract the trough position. The variations of mid-latitude trough in 41 moderate magnetic storms and 88 intense magnetic storms in the 23rd solar cycle were studied. The results show that the trough moves toward the equator as Dst index decreases and toward the pole as Dst index increases. Compared with the ICME, MC and CIR storms, in sheath storms the trough shifts to lower latitude at the end of the main phase, although the average storm intensity is weak. During the storm recovery phase, the rapid recovery of the trough position can be seen at the start of the recovery phase for moderate CIR storms. We also calculated the correlation between the minimum latitude of the trough position and the storm magnitude as well as other related main phase parameters during all storms. We found that the minimum latitude of the trough position exhibits a strong correlation with the storm magnitude during magnetic storms. However, the correlation coefficients between the trough position and other related main phase parameters are very low.[Figure not available: see fulltext.

  5. 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.

  6. 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).

  7. Parabolic approximation method for the mode conversion-tunneling equation

    SciTech Connect

    Phillips, C.K.; Colestock, P.L.; Hwang, D.Q.; Swanson, D.G.

    1987-07-01

    The derivation of the wave equation which governs ICRF wave propagation, absorption, and mode conversion within the kinetic layer in tokamaks has been extended to include diffraction and focussing effects associated with the finite transverse dimensions of the incident wavefronts. The kinetic layer considered consists of a uniform density, uniform temperature slab model in which the equilibrium magnetic field is oriented in the z-direction and varies linearly in the x-direction. An equivalent dielectric tensor as well as a two-dimensional energy conservation equation are derived from the linearized Vlasov-Maxwell system of equations. The generalized form of the mode conversion-tunneling equation is then extracted from the Maxwell equations, using the parabolic approximation method in which transverse variations of the wave fields are assumed to be weak in comparison to the variations in the primary direction of propagation. Methods of solving the generalized wave equation are discussed. 16 refs.

  8. Higher order parabolic approximations of the reduced wave equation

    NASA Technical Reports Server (NTRS)

    Mcaninch, G. L.

    1986-01-01

    Asymptotic solutions of order k to the nth are developed for the reduced wave equation. Here k is a dimensionless wave number and n is the arbitrary order of the approximation. These approximations are an extension of geometric acoustics theory, and provide corrections to that theory in the form of multiplicative functions which satisfy parabolic partial differential equations. These corrections account for the diffraction effects caused by variation of the field normal to the ray path and the interaction of these transverse variations with the variation of the field along the ray. The theory is applied to the example of radiation from a piston, and it is demonstrated that the higher order approximations are more accurate for decreasing values of k.

  9. Shock Analysis of Sentinel-3 SLSTR Parabolic Mirror Assembly

    NASA Astrophysics Data System (ADS)

    Braun, Benjamin; Kiel, Daniel

    2014-06-01

    This paper presents the different steps that have been undertaken to demonstrate the successful shock qualification of the Parabolic Mirror Assembly (PMA) in the frame of the Sentinel-3 SLSTR development. The unit has failed the first qualification shock test in terms of shift of natural frequencies and optical alignment. The objectives of the subsequent analyses are:- to correlate the finite element model with the PMA shock test on unit level,- to determine the interface loads between different parts of the PMA assembly for the PMA shock test on unit level,- to assess the PMA interface loads induced by the instrument level shock test,- to derive a reduced shock input spectrum for the PMA shock test on unit level with respect to a second qualification test.

  10. 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.

  11. Intracranial pressure increases during weightlessness: A parabolic flights study

    NASA Astrophysics Data System (ADS)

    Denise, P.; Normand, H.; Buzer, L.; Duretete, A.; Avan, P.

    2005-08-01

    The fluid shift induced by weightlessness likely induces an elevated intracranial pressure (ICP). This factor may contribute to space adaptation syndrome (SAS). Recently, it has been shown that ICP can be monitored every few seconds non invasively by otoacoustic emissions (OAE). The OAE of 6 subjects were measured along the course of parabolic flights aboard the zero-gravity A300 Airbus. Built-in noise rejection and signal processing techniques enabled valid OAE signals to be collected and analyzed online in 4 of 6 subjects. On average, the phase of 1 kHz- OAE rotated by -41° from 1 to 1.8 g, and by +78.7° at 0 g relative to 1 g. From reference invasive ICP measurements in a control group of neurosurgery patients, it is possible to infer that ICP increased by about 34 mmHg in transient weightlessness.

  12. 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.

  13. Multigrid methods for parabolic distributed optimal control problems

    NASA Astrophysics Data System (ADS)

    Borzì, Alfio

    2003-08-01

    Multigrid schemes that solve parabolic distributed optimality systems discretized by finite differences are investigated. Accuracy properties of finite difference approximation are discussed and validated. Two multigrid methods are considered which are based on a robust relaxation technique and use two different coarsening strategies: semicoarsening and standard coarsening. The resulting multigrid algorithms show robustness with respect to changes of the value of [nu], the weight of the cost of the control, is sufficiently small. Fourier mode analysis is used to investigate the dependence of the linear twogrid convergence factor on [nu] and on the discretization parameters. Results of numerical experiments are reported that demonstrate sharpness of Fourier analysis estimates. A multigrid algorithm that solves optimal control problems with box constraints on the control is considered.

  14. 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.

  15. Three-dimensional rogue waves in nonstationary parabolic potentials.

    PubMed

    Yan, Zhenya; Konotop, V V; Akhmediev, N

    2010-09-01

    Using symmetry analysis we systematically present a higher-dimensional similarity transformation reducing the (3+1) -dimensional inhomogeneous nonlinear Schrödinger (NLS) equation with variable coefficients and parabolic potential to the (1+1) -dimensional NLS equation with constant coefficients. This transformation allows us to relate certain class of localized exact solutions of the (3+1) -dimensional case to the variety of solutions of integrable NLS equation of the (1+1) -dimensional case. As an example, we illustrated our technique using two lowest-order rational solutions of the NLS equation as seeding functions to obtain rogue wavelike solutions localized in three dimensions that have complicated evolution in time including interactions between two time-dependent rogue wave solutions. The obtained three-dimensional rogue wavelike solutions may raise the possibility of relative experiments and potential applications in nonlinear optics and Bose-Einstein condensates.

  16. Three-dimensional rogue waves in nonstationary parabolic potentials

    SciTech Connect

    Yan Zhenya; Konotop, V. V.; Akhmediev, N.

    2010-09-15

    Using symmetry analysis we systematically present a higher-dimensional similarity transformation reducing the (3+1)-dimensional inhomogeneous nonlinear Schroedinger (NLS) equation with variable coefficients and parabolic potential to the (1+1)-dimensional NLS equation with constant coefficients. This transformation allows us to relate certain class of localized exact solutions of the (3+1)-dimensional case to the variety of solutions of integrable NLS equation of the (1+1)-dimensional case. As an example, we illustrated our technique using two lowest-order rational solutions of the NLS equation as seeding functions to obtain rogue wavelike solutions localized in three dimensions that have complicated evolution in time including interactions between two time-dependent rogue wave solutions. The obtained three-dimensional rogue wavelike solutions may raise the possibility of relative experiments and potential applications in nonlinear optics and Bose-Einstein condensates.

  17. 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.

  18. The dynamics and morphology of the Main Ionospheric Trough during storm active periods

    NASA Astrophysics Data System (ADS)

    Przepiórka, Dorota; Matyjasiak, Barbara; Rothkaehl, Hanna

    2015-04-01

    Mid-latitude trough, or Main Ionospheric Trough (MIT) lies on the equatorward edge of the auroral oval and plays a role as a boundary layer between the region of closed and open magnetic field lines. Here the magnetosphere-ionosphere-thermosphere coupling processes can be studied because MIT is controlled by both Earth's magnetic field and the IMF (Interplanetary Magnetic Field). MIT is well known from its magnetic storm phase dependence. With the storm onset the structure moves to lower latitudes. It narrows and deepens with the increase of the storm. During recovery phase the intensification of the electromagnetic emissions and energetic particle precipitation can be observed within the latitudes of MIT, what may explain the high variability of the trough location and shape in that time. Analysed magnetic storms have fallen into solar activity minimum, nevertheless causing strong modifications in Earth's plasma environment.

  19. Analysis of Additional CFT Support at Z=0 for the Silicon Half Trough

    SciTech Connect

    Cease, H.; Lee, A.; /Fermilab

    2000-03-20

    The D-Zero silicon trough is segmented into two half troughs. Loading to the Central Fiber Tracker Barrel 1 is at both ends and near Z = 0. The loading near Z = 0 is thought to be 4 lbs at 4 points. The point locations are at +/-45 degrees for each half trough on each side of Z = O. An additional support at Z = O is required to prevent beam sag and out of round distortions to the CFT Barrel 1. An additional joining washer will be attached between barrels 1 and 2 at Z = 0. Also a support ring will be attached to the inner diameter of barrel 1 to further help in out of round distortions. Details of the washer and loading are modeled using ANSYS.

  20. 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.

  1. Electronic Nose Functionality for Breath Gas Analysis during Parabolic Flight

    NASA Astrophysics Data System (ADS)

    Dolch, Michael E.; Hummel, Thomas; Fetter, Viktor; Helwig, Andreas; Lenic, Joachim; Moukhamedieva, Lana; Tsarkow, Dimitrij; Chouker, Alexander; Schelling, Gustav

    2017-02-01

    The presence of humans in space represents a constant threat for their health and safety. Environmental factors such as living in a closed confinement, as well as exposure to microgravity and radiation, are associated with significant changes in bone metabolism, muscular atrophy, and altered immune response, which has impacts on human performance and possibly results in severe illness. Thus, maintaining and monitoring of crew health status has the highest priority to ensure whole mission success. With manned deep space missions to moon or mars appearing at the horizon where short-term repatriation back to earth is impossible the availability of appropriate diagnostic platforms for crew health status is urgently needed. In response to this need, the present experiment evaluated the functionality and practicability of a metal oxide based sensor system (eNose) together with a newly developed breath gas collecting device under the condition of altering acceleration. Parabolic flights were performed with an Airbus A300 ZeroG at Bordeaux, France. Ambient air and exhaled breath of five healthy volunteers was analyzed during steady state flight and parabolic flight maneuvres. All volunteers completed the study, the breath gas collecting device valves worked appropriately, and breathing through the collecting device was easy and did not induce discomfort. During breath gas measurements, significant changes in metal oxide sensors, mainly sensitive to aromatic and sulphur containing compounds, were observed with alternating conditions of acceleration. Similarly, metal oxide sensors showed significant changes in all sensors during ambient air measurements. The eNose as well as the newly developed breath gas collecting device, showed appropriate functionality and practicability during alternating conditions of acceleration which is a prerequisite for the intended use of the eNose aboard the International Space Station (ISS) for breath gas analysis and crew health status

  2. 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).

  3. Three-dimensional model of plate geometry and velocity model for Nankai Trough seismogenic zone based on results from structural studies

    NASA Astrophysics Data System (ADS)

    Nakanishi, A.; Shimomura, N.; Kodaira, S.; Obana, K.; Takahashi, T.; Yamamoto, Y.; Yamashita, M.; Takahashi, N.; Kaneda, Y.

    2012-12-01

    In the Nankai Trough subduction seismogenic zone, the Nankai and Tonankai earthquakes had often occurred simultaneously, and caused a great event. In order to reduce a great deal of damage to coastal area from both strong ground motion and tsunami generation, it is necessary to understand rupture synchronization and segmentation of the Nankai megathrust earthquake. For a precise estimate of the rupture zone of the Nankai megathrust event based on the knowledge of realistic earthquake cycle and variation of magnitude, it is important to know the geometry and property of the plate boundary of the subduction seismogenic zone. To improve a physical model of the Nankai Trough seismogenic zone, the large-scale high-resolution wide-angle and reflection (MCS) seismic study, and long-term observation has been conducted since 2008. Marine active source seismic data have been acquired along grid two-dimensional profiles having the total length of ~800km every year. A three-dimensional seismic tomography using active and passive seismic data observed both land and ocean bottom stations have been also performed. From those data, we found that several strong lateral variations of the subducting Philippine Sea plate and overriding plate corresponding to margins of coseismic rupture zone of historical large event occurred along the Nankai Trough. Particularly a possible prominent reflector for the forearc Moho is recently imaged in the offshore side in the Kii channel at the depth of ~18km which is shallower than those of other area along the Nankai Trough. Such a drastic variation of the overriding plate might be related to the existence of the segmentation of the Nankai megathrust earthquake. Based on our results derived from seismic studies, we have tried to make a geometrical model of the Philippine Sea plate and a three-dimensional velocity structure model of the Nankai Trough seismogenic zone. In this presentation, we will summarize major results of out seismic studies, and

  4. 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.

  5. 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.

  6. 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.

  7. A compact representation of drawing movements with sequences of parabolic primitives.

    PubMed

    Polyakov, Felix; Drori, Rotem; Ben-Shaul, Yoram; Abeles, Moshe; Flash, Tamar

    2009-07-01

    Some studies suggest that complex arm movements in humans and monkeys may optimize several objective functions, while others claim that arm movements satisfy geometric constraints and are composed of elementary components. However, the ability to unify different constraints has remained an open question. The criterion for a maximally smooth (minimizing jerk) motion is satisfied for parabolic trajectories having constant equi-affine speed, which thus comply with the geometric constraint known as the two-thirds power law. Here we empirically test the hypothesis that parabolic segments provide a compact representation of spontaneous drawing movements. Monkey scribblings performed during a period of practice were recorded. Practiced hand paths could be approximated well by relatively long parabolic segments. Following practice, the orientations and spatial locations of the fitted parabolic segments could be drawn from only 2-4 clusters, and there was less discrepancy between the fitted parabolic segments and the executed paths. This enabled us to show that well-practiced spontaneous scribbling movements can be represented as sequences ("words") of a small number of elementary parabolic primitives ("letters"). A movement primitive can be defined as a movement entity that cannot be intentionally stopped before its completion. We found that in a well-trained monkey a movement was usually decelerated after receiving a reward, but it stopped only after the completion of a sequence composed of several parabolic segments. Piece-wise parabolic segments can be generated by applying affine geometric transformations to a single parabolic template. Thus, complex movements might be constructed by applying sequences of suitable geometric transformations to a few templates. Our findings therefore suggest that the motor system aims at achieving more parsimonious internal representations through practice, that parabolas serve as geometric primitives and that non-Euclidean variables are

  8. 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.

  9. A model of F2 peak electron densities in the main trough region of the ionosphere

    NASA Technical Reports Server (NTRS)

    Halcrow, B. W.; Nisbet, J. S.

    1977-01-01

    An empirical model of the peak electron densities in the region of the northerly main trough in the ionospheric F region is presented. The model was derived from measurements made by the satellites Alouette I and II and is in the form of a multiplicative modification factor to the CCIR peak electron density model. The model is a computer program which, when provided with the location, universal time, day number, sunspot number, and Kp index, provides the modification factor, the CCIR model prediction of Nm F2, and the new prediction including the effect of the trough. The model is expected to be of considerable use for propagation calculations in the affected region.

  10. 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.

  11. 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.

  12. Vortex shedding and galloping of open semi-circular and parabolic cylinders in cross-flow

    NASA Astrophysics Data System (ADS)

    Weaver, D. S.; Veljkovic, I.

    2005-11-01

    An experimental wind-tunnel study was undertaken to investigate the flow-induced vibration behaviour of open semi-circular and parabolic cylinders in cross-flow. The motivation for the research was to investigate the cause of the fatigue failures of a number of parabolic section rotary mixing blades in a large mixing vessel. Results are presented for force coefficients as a function of angle of incidence of the flow, Strouhal number and amplitude response. It is shown that the parabolic cylinder is subject to large amplitude vortex shedding resonance and, when the elastic axis is sufficiently downstream of the section's centre of gravity, galloping instability.

  13. 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

  14. 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.

  15. 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 ...

  16. 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....

  17. 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...

  18. 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...

  19. 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...

  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. Serum-Infliximab Trough Levels in 45 Children with Inflammatory Bowel Disease on  Maintenance Treatment

    PubMed Central

    Rolandsdotter, Helena; Marits, Per; Sundin, Ulf; Wikström, Ann-Charlotte; Fagerberg, Ulrika L.; Finkel, Yigael; Eberhardson, Michael

    2017-01-01

    The role of trough serum infliximab (s-IFX) and antibodies toward IFX (ATI) during maintenance treatment remains unclear in children. The aim of the present study was to investigate trough s-IFX and ATI to identify any correlation with inflammatory activity and clinical response in a pediatric inflammatory bowel disease (IBD) cohort. We investigated the s-IFX trough levels in pediatric IBD patients (n = 45) on maintenance IFX treatment. Ninety-three blood samples were collected and demographics, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and albumin were recorded. The mean s-IFX trough level was 5.2 µg/mL. The mean trough s-IFX level was significantly higher in the samples taken during remission (7.2 µg/mL) compared to active disease (4.5 µg/mL, p < 0.05). The trough s-IFX levels correlated with ESR, CRP, and albumin. S-IFX was undetectable in eight of the patients, all with positive ATI and active disease. Surprisingly, clinical and biochemical remission was observed at only 26 of the 93 visits. The correlation between dose variations and changes in trough s-IFX was not evident. In line with studies in adults, the s-IFX trough levels correlated with response to infliximab. PMID:28272355

  2. Analysis and two years of testing of the vee-trough concentrator/evacuated tube solar collector

    NASA Technical Reports Server (NTRS)

    Selcuk, M. K.; Aghan, A.

    1979-01-01

    The paper summarizes the mathematical analysis and presents the experimental results for a vee-trough/evacuated tube collector (VTETC). Test results reported represent the performance of the VTETC based on an aperture area. The effectiveness of vee-trough reflectors is demonstrated by comparing the useful heat collected by a receiver tube with and without concentrators.

  3. 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,…

  4. On the fractional Fisher information with applications to a hyperbolic-parabolic system of chemotaxis

    NASA Astrophysics Data System (ADS)

    Granero-Belinchón, Rafael

    2017-02-01

    We introduce new lower bounds for the fractional Fisher information. Equipped with these bounds we study a hyperbolic-parabolic model of chemotaxis and prove the global existence of solutions in certain dissipation regimes.

  5. On the Approximate Controllability of Some Semilinear Parabolic Boundary-Value Problems

    SciTech Connect

    Diaz, J. I.; Henry, J.; Ramos, A. M.

    1998-01-15

    We prove the approximate controllability of several nonlinear parabolic boundary-value problems by means of two different methods: the first one can be called a Cancellation method and the second one uses the Kakutani fixed-point theorem.

  6. Numerical analysis of the rescaling method for parabolic problems with blow-up in finite time

    NASA Astrophysics Data System (ADS)

    Nguyen, V. T.

    2017-01-01

    In this work, we study the numerical solution for parabolic equations whose solutions have a common property of blowing up in finite time and the equations are invariant under the following scaling transformation

  7. 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.

  8. 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.

  9. 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

  10. Growth faulting and salt diapirism; their relationship and control in the Carolina Trough, eastern North America

    USGS Publications Warehouse

    Dillon, William P.; Popenoe, Peter; Grow, John A.; Klitgord, Kim D.; Swift, B. Ann; Paull, Charles K.; Cashman, Katharine V.

    1982-01-01

    The Carolina Trough is a long, linear, continental margin basin off eastern North America. Salt domes along the trough's seaward side show evidence of active diapirism and a normal growth fault along its landward side has been continually active at least since the end of the Jurassic. This steep fault extends to a strong reflection event at about 11 km depth that may represent the top of a salt layer. We infer that faulting is caused by seaward flow of salt from the deep part of the trough into domes, thereby removing support for the overlying block of sedimentary rock. Diapirs off eastern North America seem to be concentrated in the Carolina Trough and Scotian Basin, where basement seems to be thinner than in other basins off eastern North America, south of Newfo ndland. Thinner basement, probably due to greater stretching during rifing, may have resulted in earlier subsidence below sea level, a longer life for the salt evaporating pans in these basins, and thus a thicker salt layer, which would be more conducive to diapirism.

  11. 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.

  12. 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

  13. Processes of sedimentation associated with fault-controlled trough across a shelf

    SciTech Connect

    Rees, M.N.

    1985-02-01

    Western North America was a rapidly subsiding, passive continental margin during the Cambrian. During the Middle Cambrian, a belt of carbonate deposition dominated the central shelf. It was bounded by fine-grained terrigenous sediments that accumulated in deep water to the west and in shallow water to the east. Movement along a high-angle fault that extended across the shelf produced a conspicuous embayment into the carbonate belt in Nevada and Utah during the middle Middle Cambrian. This fault movement controlled basin geometry and distribution of carbonate and shale lithofacies on the shelf for at least the next 40 m.y. The embayment was an asymmetrical trough that deepened and widened as it extended some 400 km westward toward the edge of the continent. South of its abrupt southern margin, which marked the position of the fault, shallow subtidal and peritidal sediments accumulated throughout the Middle Cambrian. The northern flank of the embayment was a drowned platform that sloped gently southward into the trough axis. On this ramp, a carbonate platform was rapidly reestablished through vertical accretion and progradation. In the trough axis, which lay near the faulted margin, sediments representing anoxic and deep-water environments accumulated throughout the middle and late Middle Cambrian. Sedimentation rates in this axial region were inadequate to reestablish a shallow-water depositional setting because of reactivation of faulting and because the trough acted as a sediment bypass zone.

  14. 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.

  15. 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.

  16. Micro-origin of no-trough trapping in self-excited nonlinear dust acoustic waves.

    PubMed

    Chang, Mei-Chu; Teng, Lee-Wen; I, Lin

    2012-04-01

    We experimentally investigate the micro-origin of the absence of trough trapping in nonlinear traveling dust acoustic waves self-excited by the downward ion flow in the dissipative dusty plasma. The wave forms of dust density, the drag force from the background neutrals, ions, and dusts, and the effective potential energy for dusts are constructed by tracking dust motion and measuring the velocity and the position-dependent forces. The tilted washboard type potential wave form with a slight phase lead to the dust density wave form is obtained. It provides sufficient kinetic energy to compensate drag dissipation and move dusts from the dust density trough to the crest front. The dusts with sufficient energy overcome the downward pushing by the crest front, climb over the crest, and sustain the oscillatory motion with upward drift. Those dusts with insufficient energy to climb over the potential barrier of the crest are trapped in and move downward with the crest front, until kicked upward by fluctuation. The upward neutral dominated drag force prevents them from sliding down the potential energy hill at the crest front and further oscillating in the trough. It leads to the absence of trough trapping.

  17. Investigation of Marine Magnetic Vector Anomalies in the Southern Ayu Trough, Southern Philippine Sea

    NASA Astrophysics Data System (ADS)

    Kim, S.; Lee, S.

    2001-12-01

    The Ayu Trough is a divergent margin, located at the boundary of the Philippine Sea and the Caroline Plates. Previous attempts to resolve the magnetic lineations of this region using total magnetic field have not been successful because it represents a case of east-west spreading center situated near the magnetic equator. The difficulty is compounded by the fact that the Ayu Trough is an ultra-slow-spreading center, which exhibits a complex history of evolution. As an attempt to get around the inherent ambiguity of total field measurement, a shipboard three-component magnetometer was employed during our recent cruise to the Ayu Trough along with proton precession magnetometer. This study examines the vector magnetic data collected in the south part of the Ayu Trough and compares them with tectonic features identified from other geophysical measurements. First, the magnetic field due to the ship was removed from the measured field. We then subtracted the International Geomagnetic Reference Field and the diurnal variation recorded at Guam observatory from our measurement. The amplitude of the north-south component anomalies is substantially less than that of other anomalies, which suggests that the general strike of magnetic lineations in this region is north-south. The magnetic boundary and their strike were estimated by assuming that the magnetic sources are two-dimensional. On the basis of its tectonic structure and interpretation of the total field anomaly pattern, the Ayu Trough can be divided into two sections with distance from the axis: the exterior (> 100 km from the axis) which shows evidence of rifted margin and the interior (< 100 km from the axis) which exhibits the characteristics of seafloor spreading. The vector magnetic anomaly appears to be useful in determining major boundaries, such as those between the exterior and interior sections in our area. Within the interior section of the Ayu Trough, however, the discrimination of magnetic boundaries was

  18. Parabolic tailored-potential quantum-wires grown in inverted pyramids

    NASA Astrophysics Data System (ADS)

    Lazarev, M.; Szeszko, J.; Rudra, A.; Karlsson, K. F.; Kapon, E.

    2015-03-01

    Quasi-one-dimensional AlGaAs quantum wires (QWRs) with parabolic heterostructure profiles along their axis were fabricated using metallorganic vapor phase epitaxy (MOVPE) on patterned (111)B GaAs substrates. Tailoring of the confined electronic states via modification in the parabolic potential profile is demonstrated using model calculations and photoluminescence spectroscopy. These novel nanostructures are useful for studying the optical properties of systems with dimensionality between zero and one.

  19. Comparison of Fresnel lenses and parabolic mirrors as solar energy concentrators

    SciTech Connect

    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.

  20. 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.

  1. 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.

  2. Comparison of Different Implementation Options for Density Discontinuity in Split Step Fourier Parabolic Equation Models

    DTIC Science & Technology

    2014-03-01

    method to the numerical solution of nonlinear and variable coefficient wave equations ,” SIAM, vol. 15, no. 2, pp. 423, Apr. 1973. [3] D. Lee and S. T...DIFFERENT IMPLEMENTATION OPTIONS FOR DENSITY DISCONTINUITY IN SPLIT– STEP FOURIER PARABOLIC EQUATION MODELS by Matthew D. Owens March 2014...FOR DENSITY DISCONTINUITY IN SPLIT–STEP FOURIER PARABOLIC EQUATION MODELS 5. FUNDING NUMBERS 6. AUTHOR(S) Matthew D. Owens 7. PERFORMING

  3. Dense Ocean Floor Network for Earthquakes and Tsunamis; DONET/ DONET2, Part2 -Development and data application for the mega thrust earthquakes around the Nankai trough-

    NASA Astrophysics Data System (ADS)

    Kaneda, Y.; Kawaguchi, K.; Araki, E.; Matsumoto, H.; Nakamura, T.; Nakano, M.; Kamiya, S.; Ariyoshi, K.; Baba, T.; Ohori, M.; Hori, T.; Takahashi, N.; Kaneko, S.; Donet Research; Development Group

    2010-12-01

    Yoshiyuki Kaneda Katsuyoshi Kawaguchi*, Eiichiro Araki*, Shou Kaneko*, Hiroyuki Matsumoto*, Takeshi Nakamura*, Masaru Nakano*, Shinichirou Kamiya*, Keisuke Ariyoshi*, Toshitaka Baba*, Michihiro Ohori*, Narumi Takakahashi*, and Takane Hori** * Earthquake and Tsunami Research Project for Disaster Prevention, Leading Project , Japan Agency for Marine-Earth Science and Technology (JAMSTEC) **Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) DONET (Dense Ocean Floor Network for Earthquakes and Tsunamis) is the real time monitoring system of the Tonankai seismogenic zones around the Nankai trough southwestern Japan. We were starting to develop DONET to perform real time monitoring of crustal activities over there and the advanced early warning system. DONET will provide important and useful data to understand the Nankai trough maga thrust earthquake seismogenic zones and to improve the accuracy of the earthquake recurrence cycle simulation. Details of DONET concept are as follows. 1) Redundancy, Extendable function and advanced maintenance system using the looped cable system, junction boxes and the ROV/AUV. DONET has 20 observatories and incorporated in a double land stations concept. Also, we are developed ROV for the 10km cable extensions and heavy weight operations. 2) Multi kinds of sensors to observe broad band phenomena such as long period tremors, very low frequency earthquakes and strong motions of mega thrust earthquakes over M8: Therefore, sensors such as a broadband seismometer, an accelerometer, a hydrophone, a precise pressure gauge, a differential pressure gauge and a thermometer are equipped with each observatory in DONET. 3) For speedy detections, evaluations and notifications of earthquakes and tsunamis: DONET system will be deployed around the Tonankai seismogenic zone. 4) Provide data of ocean floor crustal deformations derived from pressure sensors: Simultaneously, the development of data

  4. Novel solar cogeneration trough system based on stretched microstructured mylar film

    NASA Astrophysics Data System (ADS)

    Hejmadi, Vic; Shin, Meimei; Kress, Bernard; Giliberto, Alfredo

    2011-05-01

    Hybrid CSP / CPV (Concentrating Solar Power / Concentration Photovoltaic) systems provide a good alternative to traditional CPV systems or CSP trough architectures. Such systems are often described as solar cogeneration systems. Trough systems use mainly the IR portion of the spectrum in order to heat up a pipe in which water is circulating. CPV systems use only the visible portion of the spectrum to produce the photo-voltaic conversion. Due to the achromatic nature of traditional thermal trough CSP systems, it is very unlikely that a CPV system can be integrated with a CSP system, even a low concentration CPV system (LCPV). We propose a novel technique to implement a low concentration CSP/LCPV system which relies on commercially available solar trough concentrators / trackers that use reflective stretched Mylar membranes. However, here the Mylar is embossed with microstructures that act only on the visible portion of the spectrum, leaving the infrared part of the solar spectrum unperturbed. This architecture has many advantages, such as: the existing Mylar-based thermal trough architecture is left unperturbed for optimal thermal conversion, with linear strips of PV cells located a few inches away from the central water pipe; the infrared radiation is focused on the central pipe, away from the PV cells, which remain relatively cool compared to conventional LCPV designs (only visible light (the PV convertible part of the solar spectrum) is diffracted onto the PV cell strips); and the Mylar sheets can be embossed by conventional roll-to-roll processes, with a one-dimensional symmetric micro-structured pattern. We show how the positive master elements are designed and fabricated over a small area (using traditional IC wafer fabrication techniques), and how the Mylar sheets are embossed by a recombined negative nickel shim. We also show that such a system can efficiently filter the visible spectrum and divert it onto the linear strips of PV cells, while leaving the

  5. 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%.

  6. 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.

  7. 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

  8. Comparison of parabolic filtration methods for 3D filtered back projection in pulsed EPR imaging

    NASA Astrophysics Data System (ADS)

    Qiao, Zhiwei; Redler, Gage; Epel, Boris; Halpern, Howard J.

    2014-11-01

    Pulse electron paramagnetic resonance imaging (Pulse EPRI) is a robust method for noninvasively measuring local oxygen concentrations in vivo. For 3D tomographic EPRI, the most commonly used reconstruction algorithm is filtered back projection (FBP), in which the parabolic filtration process strongly influences image quality. In this work, we designed and compared 7 parabolic filtration methods to reconstruct both simulated and real phantoms. To evaluate these methods, we designed 3 error criteria and 1 spatial resolution criterion. It was determined that the 2 point derivative filtration method and the two-ramp-filter method have unavoidable negative effects resulting in diminished spatial resolution and increased artifacts respectively. For the noiseless phantom the rectangular-window parabolic filtration method and sinc-window parabolic filtration method were found to be optimal, providing high spatial resolution and small errors. In the presence of noise, the 3 point derivative method and Hamming-window parabolic filtration method resulted in the best compromise between low image noise and high spatial resolution. The 3 point derivative method is faster than Hamming-window parabolic filtration method, so we conclude that the 3 point derivative method is optimal for 3D FBP.

  9. 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.

  10. 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.

  11. 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.

  12. A parabolized stability analysis of a trailing vortex wake

    NASA Astrophysics Data System (ADS)

    Edstrand, Adam; Schmid, Peter; Taira, Kunihiko; Cattafesta, Louis

    2016-11-01

    To aid in understanding how best to control a trailing vortex, we perform a parabolized stability analysis on a flow past a wing at a chord-based Reynolds number of 1000. At the upstream position, the wake instability branch dominates, with only a single vortex instability present in the spectrum. With downstream progression, the growth rate of the wake instability decays, but remains unstable 10 chords downstream. With the wake mode being unstable so far downstream, these results imply that the excitation of the wake instability, despite the varying base flow, will continue to see growth and potentially disrupt the trailing vortex. Conversely, the vortex instability in its formative region rapidly decays to the stable half-plane, then at 11 chords downstream becomes unstable again. We hypothesized the renewed instability growth far downstream is developing as a result of vortex instabilities, however the excitation of these instabilities proves to be challenging in the vortex far field. From these results, control near the two-dimensional wake behind the airfoil may better interfere with the trailing vortex formation; however, to determine the optimal disturbances, an adjoint analysis is required and is included in the future work of the project. ONR Grants N00014-10-1-0832 and N00014-15-1-2403.

  13. 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.

  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.

  16. High Speed Analysis Of Free Flights With A Parabolic Thruster

    SciTech Connect

    Scharring, Stefan; Eckel, Hans-Albert; Roeser, Hans-Peter

    2010-05-06

    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.

  17. Approximate controllability of a system of parabolic equations with delay

    NASA Astrophysics Data System (ADS)

    Carrasco, Alexander; Leiva, Hugo

    2008-09-01

    In this paper we give necessary and sufficient conditions for the approximate controllability of the following system of parabolic equations with delay: where [Omega] is a bounded domain in , D is an n×n nondiagonal matrix whose eigenvalues are semi-simple with nonnegative real part, the control and B[set membership, variant]L(U,Z) with , . The standard notation zt(x) defines a function from [-[tau],0] to (with x fixed) by zt(x)(s)=z(t+s,x), -[tau][less-than-or-equals, slant]s[less-than-or-equals, slant]0. Here [tau][greater-or-equal, slanted]0 is the maximum delay, which is supposed to be finite. We assume that the operator is linear and bounded, and [phi]0[set membership, variant]Z, [phi][set membership, variant]L2([-[tau],0];Z). To this end: First, we reformulate this system into a standard first-order delay equation. Secondly, the semigroup associated with the first-order delay equation on an appropriate product space is expressed as a series of strongly continuous semigroups and orthogonal projections related with the eigenvalues of the Laplacian operator (); this representation allows us to reduce the controllability of this partial differential equation with delay to a family of ordinary delay equations. Finally, we use the well-known result on the rank condition for the approximate controllability of delay system to derive our main result.

  18. Motion sickness susceptibility in parabolic flight and velocity storage activity

    NASA Technical Reports Server (NTRS)

    Dizio, Paul; Lackner, James R.

    1991-01-01

    In parabolic flight experiments, postrotary nystagmus is as found to be differentially suppressed in free fall (G) and in a high gravitoinertial force (1.8 G) background relative to 1 G. In addition, the influence of postrotary head movements on nystagmus suppression was found to be contingent on G-dependency of the velocity storage and dumping mechanisms. Here, susceptibility to motion sickness during head movements in 0 G and 1.8 G was rank-correlated with the following: (1) the decay time constant of the slow phase velocity of postrotary nystagmus under 1 G, no head movement, baseline conditions, (2) the extent of time constant reduction elicited in 0 G and 1.8 G; (3) the extent of time constant reduction elicited by head tilts in 1 G; and (4) changes in the extent of time constants reduction in 0 G and 1.8 G over repeated tests. Susceptibility was significantly correlated with the extent to which a head movement reduced the time constant in 1 G, was weakly correlated with the baseline time constant, but was not correlated with the extent of reduction in 0 G or 1.8 G. This pattern suggests a link between mechanisms evoking symptoms of space motion sickness and the mechanisms of velocity storage and dumping. Experimental means of evaluating this link are described.

  19. 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

  20. How much do we understand the structure and evolution of the Salton Trough?

    NASA Astrophysics Data System (ADS)

    Janecke, S. U.; Dorsey, R. J.; Langenheim, V. E.

    2008-12-01

    The Salton Trough, at the northern end of the Gulf of California, likely formed by different processes than the central and southern Gulf due to the weak rheology of its thick quartz-rich sedimentary fill and its proximity to the transpressional Big Bend and the Eastern California shear zone. Many of its key early structures are buried or poorly exposed, so it is unclear whether deep patches of mafic crust were produced by NE-trending mid-ocean-ridge segments, by E-W extension akin to that seen in the Wagner basin, or by some other process. Three distinct tectonic regimes produced the Salton Trough. (1) Late Miocene extension is poorly understood because much of the record is in the subsurface, and existing evidence from thermochronology in the Sierra el Major and Anza Borrego Park suggests extensional exhumation as old as 10-15 Ma, whereas the oldest stratigraphic evidence for extension is ca. 8-6 Ma. (2) Regional-scale, large-magnitude transtensional deformation began in late Miocene or early Pliocene time (ca. 8-6 Ma). The paleo-San Andreas fault took up most of the strain, with additional dextral shear and extension on detachment faults with breakaways in the W, central? and SE Salton Trough. (3) Pleistocene to modern wrench tectonics followed a massive reorganization at about 1.1-1.3 Ma. Detachment faults were cut, folded and largely abandoned, new dextral faults formed SW of the San Andreas fault, and the SE 2/3 of the paleo-San Andreas fault became inactive. The Imperial, Cerro Prieto, San Jacinto, Elsinore, and San Felipe faults and the Brawley seismic zone all date to this latest period of deformation. The Salton Trough has been interpreted to contain a smothered pair of oceanic spreading centers beneath the Salton Sea and Cerro Prieto geothermal field, two regions of high heat flow and latest Pleistocene volcanism. Patches of dense mafic crust at depth beneath 5-10? km of Pliocene to Holocene sediment and metasedimentary rocks produce two principal

  1. 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

  2. 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

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. Hydrocarbon geochemistry of hydrothermally generated petroleum from Escanaba trough, offshore Californi U.S.A.

    USGS Publications Warehouse

    Kvenvolden, K.A.; Rapp, J.B.; Hostettler, F.D.

    1990-01-01

    In 1986, three samples of sulfide-rich sediments, impregnated with hydrothermally derived, asphaltic petroleum, were recovered in a dredge and by submersible from Escanaba Trough, the sediment-covered, southern end of the Gorda Ridge spreading axis, offshore northern California. The molecular distributions of hydrocarbons in the two pyrrhotite-rich samples recovered by submersible are similar and compare well the hydrocarbon composition of the first pyrrhotite-rich samples containing petroleum discovered at a 1985 dredge site about 30 km to the south of the site of the submersible dive. In contrast, the 1986 dredge sample, composed of a polymetallic assemblage of sulfides, containes petroleum in which the distribution of hydrocarbons indicates a slightly higher of maturity relative to the other samples. The observation that petroleum of variable composition occurs with metallic sulfides at two and probably more distinct site indicates that petroleum generation may be a common process in the hydrothermally active Escanaba Trough. ?? 1990.

  8. Fowrward modeeling of the Bureba escarpment (Rioja Trough, N-Spain)

    NASA Astrophysics Data System (ADS)

    Mikeš, Daniel

    2009-12-01

    In this work I use the numerical model TAO to study the evolution of the Bureba escarpment, sitting at the watershed between Duero and Ebro Basins and draining into the Rioja Trough. Facies correlation across this area is troublesome through lack of age-dates and therefore timing of tectonosedimentary events is controversial. Numerical modelling should shed some light on the evolution of this area. To that end I have run homogeneous and heterogeneous models for a range of values of erodability, runoff and elastic thickness. The models demonstrate that the tilting of the NE Duero could have resulted from isostatic compensation to erosion in the Rioja Trough and that the Bureba escarpment is a natural barrier to erosion preventing escarpment retreat for at least the next 1 My.

  9. Forward modelling of the Bureba escarpment (Rioja Trough, N-Spain)

    NASA Astrophysics Data System (ADS)

    Mikeš, Daniel

    2009-12-01

    In this work I use the numerical model TAO to study the evolution of the Bureba escarpment, sitting at the watershed between Duero and Ebro Basins and draining into the Rioja Trough. Facies correlation across this area is troublesome through lack of age-dates and therefore timing of tectonosedimentary events is controversial. Numerical modelling should shed some light on the evolution of this area. To that end I have run homogeneous and heterogeneous models for a range of values of erodability, runoff and elastic thickness. The models demonstrate that the tilting of the NE Duero could have resulted from isostatic compensation to erosion in the Rioja Trough and that the Bureba escarpment is a natural barrier to erosion preventing escarpment retreat for at least the next 1 My.

  10. Studies of sporadic E (Es) associated with the main ionospheric trough

    SciTech Connect

    Rodger, A.S.; Morrell, C.; Dudeney, J.R.

    1983-11-01

    Sporadic E, or E(s) events under the main F region trough have been confirmed on the basis of ionograms from a vertical incidence ionosonde at Halley Bay, Antarctica. Analyses indicate that E(s) is frequently observable under both the equatorward and the poleward edges of the trough, as well as poleward of it. Before magnetic midnight, E(s) layers whose semithickness resembles those of the normal E layer are common, in contrast to layers seen after magnetic midnight which show the characteristics of thin E(s) layers. A possible explanation of the observed change in the E(s) layer characteristics at magnetic midnight is related to differences in the type and spectra of the precipitating particles. It is shown that the redistribution of ionization by the convection electric field may be important. 40 references.

  11. Earthquake swarms driven by aseismic creep in the Salton Trough, California

    NASA Astrophysics Data System (ADS)

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

    2007-04-01

    In late August 2005, a swarm of more than a thousand earthquakes between magnitudes 1 and 5.1 occurred at the Obsidian Buttes, near the southern San Andreas Fault. This swarm provides the best opportunity to date to assess the mechanisms driving seismic swarms along transform plate boundaries. The recorded seismicity can only explain 20% of the geodetically observed deformation, implying that shallow, aseismic fault slip was the primary process driving the Obsidian Buttes swarm. Models of earthquake triggering by aseismic creep can explain both the time history of seismic activity associated with the 2005 swarm and the ˜1 km/h migration velocity exhibited by this and several other Salton Trough earthquake swarms. A combination of earthquake triggering models and denser geodetic data should enable significant improvements in time-dependent forecasts of seismic hazard in the key days to hours before significant earthquakes in the Salton Trough.

  12. Fixed flat plate collector with a reversible vee-trough concentrator

    NASA Technical Reports Server (NTRS)

    Selcuk, M. K.

    1976-01-01

    An asymmetrical-reversible vee-trough concentrator for use both with nonevacuated and evacuated receivers is proposed in order to improve the performance of a fixed flat plate collector. The device is capable of maintaining a year-round concentration factor of about 2 while eliminating the complications of the tilt adjustments of the collector box assembly. Efficiency improvements and cost reductions for temperatures of about 100 and 200 C are offered for the nonvacuum and vacuum tube versions, respectively. A major advantage of the vee-trough is the enhancement of the incident flux, thus extending the collection period. The vacuum collector is suitable for supplying heat to solar Rankine systems, while the nonvacuum version can be used for air conditioning purposes via an absorption air conditioner.

  13. Empirical model of plasma convection at latitudes of the main ionization trough

    NASA Astrophysics Data System (ADS)

    Filippov, V. M.

    1984-06-01

    The proposed empirical model is based on measurements of plasma drift velocity using the short-baseline diversity reception technique at Zhigansk (L = 4) and Iakutsk (L = 3). Results obtained with the model indicate that the principal mechanism for the formation of the main trough is weak plasma convection at subauroral latitudes in conditions of the absence of ionization sources and the 'impoverishment' of F-region plasma due to the usual recombination processes.

  14. Evidence for Recent Liquid Water on Mars: Gullies in Sirenum Fossae Trough

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This mosaic of two Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images shows about 20 different gullies coming down the south-facing wall of a trough in the Sirenum Fossae/Gorgonum Chaos region of the martian southern hemisphere. Each channel and its associated fan--or apron--of debris appears to have started just below the same hard, resistant layer of bedrock located approximately 100 meters (about 325 feet) below the top of the trough wall. The layer beneath this hard, resistant bedrock is interpreted to be permeable, which allows ground water to percolate through it and--at the location of this trough--seep out onto the martian surface. The channels and aprons only occur on the south-facing slope of this valley created by faults on each side of the trough. The depression is approximately 1.4 km (0.9 mi) across.

    The mosaic was constructed from two pictures taken on September 16, 1999, and May 1, 2000. The black line is a gap between the two images that was not covered by MOC. The scene covers an area approximately 5.5 kilometers (3.4 miles) wide by 4.9 km (3.0 mi) high. Sunlight illuminates the area from the upper left. The image is located near 38.5oS, 171.3oW. MOC high resolution images are taken black-and-white (grayscale); the color seen here has been synthesized from the colors of Mars observed by the MOC wide angle cameras and by the Viking Orbiters in the late 1970s.

  15. Deepwater redox changes in the southern Okinawa Trough since the last glacial maximum

    NASA Astrophysics Data System (ADS)

    Dou, Yanguang; Yang, Shouye; Li, Chao; Shi, Xuefa; Liu, Jihua; Bi, Lei

    2015-06-01

    In this study, rare earth element (REE) was treated as a paleo-redox proxy to investigate the changes of depositional environment in the southern Okinawa Trough since the last glacial maximum. The acid-leachable fraction (leachate) of the sediments recovered from the ODP Site 1202B is dominated by biogenic and authigenic components while detrital contamination is minor. The significant enrichment of middle REE suggests a large contribution from authigenic Mn oxyhydroxides and cerium (Ce) anomaly can indicate deepwater redox change. The REE parameters including Ce anomaly in the leachate exhibit remarkable and abrupt changes in the early Holocene (∼9.5 ka) and during LGM (∼20 ka). An increase of Ce anomaly at 28-22 ka implies the suboxic deepwater condition probably caused by increased primary productivity. Weak positive Ce anomalies during the last glacial maximum and deglaciation suggest an oxic depositional environment responding to the enhanced deepwater ventilation with the advection of the North Pacific Intermediate Water and/or South China Sea Intermediate Water into the trough. A decrease of Ce anomaly in the early Holocene might be caused by the intrusion and strengthening of the Kuroshio Current in the trough that enhanced the water stratification and induced a gradual development of suboxic depositional condition. Furthermore, an abrupt change of chemical composition at ca. 4 ka probably indicates a decrease of dissolved oxygen in deepwater and a weakening of ventilation in the Okinawa Trough. This study suggests that REE proxy can provide new insights into the linkage among surface current, deepwater circulation and sediment record in the continental margin where terrigenous input dominates.

  16. Mesozoic evolution of the Valencia trough: Implications for the understanding of the Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Etheve, Nathalie; Frizon de Lamotte, Dominique; Mohn, Geoffroy; Roca, Eduard; Gorini, Christian; Blanpied, Christian

    2014-05-01

    The Western Mediterranean records a multi-stage tectonic evolution characterized by a complex succession of rifting to compressive episodes during the Cenozoic. The Valencia through was formed in this geodynamic framework and is classically interpreted as an aborted Tertiary rift related to back-arc extension. Notably, the Tertiary rifting is superimposed to the Jurassic opening of the Tethys basin, the early Cretaceous opening of the Bay of Biscay-Pyrenees basins and the late Cretaceous-early Tertiary inversion of these basins (e.g. Iberian range, Catalan Coastal range). Since the last twenty years, many studies contributed to the understanding of the Tertiary history of this area, whereas the pre-Tertiary evolution of the Valencia trough remains poorly investigated. Therefore, we initiated a research project in the Valencia trough benefiting from the acquisition of high quality seismic surveys allowing a better imaging of the Mesozoic sequences. This PhD project aims to understand the mechanisms and the role of structural inheritance that controlled the evolution of the Valencia trough and its impact on the sedimentary infilling since the Mesozoic. The relation between the sedimentary infilling, subsidence and crustal thinning mechanisms during the Cenozoic are investigated aiming to unravel critical information on rifting processes. This study will be based on correlations between onshore and offshore observations. Structural and stratigraphic evolution will be defined on land and compared with seismic sections and well data at sea. Eventually, these data will enable us to propose coherent land-sea interpretations of the area, providing a better understanding of the tectono-stratigraphic context. Our poster show preliminary results obtained from fieldwork on the western margin of the Valencia trough coupled with seismic interpretations. Eventually, results of this study may lead to better constrain the kinematic reconstruction of the western Mediterranean

  17. Gafsa trough of central Tunisia: Basin evolution and maturation of hydrocarbons

    SciTech Connect

    Schamel, S.; Reed, J.K. ); Traut, M. ); Hassine, B.K. )

    1991-03-01

    The Gafsa trough of onshore central Tunisia is one of the more interesting and underexplored features of North Africa. It is a 5-12 km deep, east-west-trending depression along the inner edge of the Tunisian-Libyan shelf margin. The basin has had a long and virtually uninterrupted history of subsidence from the late Paleozoic into the early Cenozoic. Subsidence began in the late Carboniferous, soon after the close of the Hercynian orogeny, and resulted in deposition of a 3000+ m succession of Permo-Carboniferous carbonates and shale that pinches out southward onto the Saharan Flexure. The tectonic setting for this earliest phase of subsidence is not clear. The main episode of subsidence, which began in the Middle Triassic, continued through the Jurassic as left-lateral, transtensional rifting along the South Saharan and Maghrebian Shear zones. A set of organic maturation maps for onshore central Tunisia depicts the minimum time of entry into the oil and gas generative windows of the two potential source rocks in the region, the Lower Silurian Tannezufft Formation and Middle-Upper Jurassic basinal shales. Maturation modeling suggests that the Lower Silurian source rocks beneath the deeper portions of the Gafsa trough are overmature, even for generation of dry gas. Everywhere north of the Saharan Flexure potential Paleozoic source rocks are highly mature to overmature. The Middle-Upper Jurassic basinal shales in the deeper, central portions of the Gafsa trough entered the oil generative window as early as mid-cretaceous time and into the gas generative window in the Late Cretaceous - early Tertiary. These possible source rocks are mature to highly mature beneath nearly all of the basin. The Gafsa trough is a probable gas province, with occurrences of condensate possible.

  18. Curvilinear parabolic approximation for surface wave transformation with wave-current interaction

    SciTech Connect

    Shi Fengyan . E-mail: fyshi@coastal.udel.edu; Kirby, James T.

    2005-04-10

    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.

  19. Hydrogeology of the Valley-Fill Aquifer in the Onondaga Trough, Onondaga County, New York

    USGS Publications Warehouse

    Kappel, William M.; Miller, Todd S.

    2005-01-01

    Continuing efforts to improve water quality in Onondaga Lake, New York and its tributaries require an understanding of how the natural, brine-filled aquifer in the Onondaga Trough (valley) affects the freshwater in Onondaga Lake. The city of Syracuse, locally known as 'The Salt City,' was built around the salt springs, which issued from a valley-fill aquifer that contains a highly concentrated brine (up to six times as salty as sea water), but little is known about the source of the brine, its movement within the glacial sediments that partly fill the Onondaga Trough, and the interaction of the aquifer and the lake. This report summarizes initial data-collection and analysis efforts in the 25-mile long Onondaga Trough that extends from near Tully, N.Y., to the outlet of Onondaga Lake and presents results of some initial chemical and geographic analyses that will lead to the development of a mathematical ground-water-flow model of the valley-fill aquifer.

  20. Interactions of the Greater Ontong Java mantle plume component with the Osbourn Trough.

    PubMed

    Zhang, Guo-Liang; Li, Chao

    2016-11-21

    The Ontong Java-Manihiki-Hikurangi plateau (OJMHP) is considered to have originated from a starting mantle plume, and have been rifted apart by two spreading ridges. However, the ages of these spreading ridges and their possible interactions with the presumed mantle plume are unclear. The Manihiki-Hikurangi plateau has been rifted apart by the Osbourn Trough which formed the southwestern Pacific crust to the east of the Tonga-Kermadec trench. Here we report Pb-Hf-Os isotopes of the basaltic crust (Site U1365 of IODP Expedition 329) formed by the Osbourn Trough. Linear regression of Re-Os isotopes results in an age of 103.7 ± 2.3 Ma for Site U1365 basalts, indicating that the Manihiki-Hikurangi plateau was rifted apart by the Osbourn Trough with a spreading rate of ~190 mm/yr. The superfast spreading rate supports the Osbourn as an abandoned segment of the early Pacific spreading ridge, which initially overlapped with the giant starting plume. Moreover, the Pb-Hf isotopes of some of Site U1365 basalts show distinct differences from those of the Pacific mid-ocean ridge basalts, while they are similar to the basalts of the Ontong Java and Manihiki plateaus. We suggest that the OJMHP mantle plume components has been involved by the Osbourn spreading center.