WorldWideScience

Sample records for hybrid parabolic dish

  1. Parabolic Dish Stirling Module

    Science.gov (United States)

    Washom, B.

    1984-01-01

    The design, manufacture, and assembly of a commercially designed parabolic dish Stirling 25 kWe module is examined. The cost, expected performance, design uniquenesses, and future commercial potential of this module, which is regarded as the most technically advanced in the parabolic dish industry is discussed.

  2. Optical design and optimization of parabolic dish solar concentrator with a cavity hybrid receiver

    Science.gov (United States)

    Blázquez, R.; Carballo, J.; Silva, M.

    2016-05-01

    One of the main goals of the BIOSTIRLING-4SKA project, funded by the European Commission, is the development of a hybrid Dish-Stirling system based on a hybrid solar-gas receiver, which has been designed by the Swedish company Cleanergy. A ray tracing study, which is part of the design of this parabolic dish system, is presented in this paper. The study pursues the optimization of the concentrator and receiver cavity geometry according to the requirements of flux distribution on the receiver walls set by the designer of the hybrid receiver. The ray-tracing analysis has been performed with the open source software Tonatiuh, a ray-tracing tool specifically oriented to the modeling of solar concentrators.

  3. Shenandoah parabolic dish solar collector

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, G.S.

    1985-01-01

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

  4. Shenandoah parabolic dish solar collector

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Parabolic dish collectors - A solar option

    Science.gov (United States)

    Truscello, V. C.

    1981-01-01

    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.

  6. Commercialization of parabolic dish systems

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  9. The JPL parabolic dish project. [solar collectors technology development

    Science.gov (United States)

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

    1980-01-01

    The parabolic dish solar collector is a highly versatile concentrating collector system that can produce heat for many thermal processes and electricity by coupling the collector to a suitable heat engine. This paper discusses a project for the development of these collector systems and summarizes contracts with industry for developing the dish subsystems which include concentrator, receiver, and heat engine. An early market for dishes is the dispersed small community market which depends heavily on oil to operate diesel or steam turbine plants in order to generate electricity. The present contracts with industry for conducting engineering experiments using the developed dish hardware to demonstrate the technology in these early opportunity markets is also discussed.

  10. Irrigation market for solar thermal parabolic dish systems

    Science.gov (United States)

    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.

  11. Mechanical design of a low cost parabolic solar dish concentrator

    Directory of Open Access Journals (Sweden)

    Hamza Hijazi

    2016-03-01

    Full Text Available The objective of this research was to design a low cost parabolic solar dish concentrator with small-to moderate size for direct electricity generation. Such model can be installed in rural areas which are not connected to governmental grid. Three diameters of the dish; 5, 10 and 20 m are investigated and the focal point to dish diameter ratio is set to be 0.3 in all studied cases. Special attention is given to the selection of the appropriate dimensions of the reflecting surfaces to be cut from the available sheets in the market aiming to reduce both cutting cost and sheets cost. The dimensions of the ribs and rings which support the reflecting surface are optimized in order to minimize the entire weight of the dish while providing the minimum possible total deflection and stresses in the beams. The study applies full stress analysis of the frame of the dish using Autodesk Inventor. The study recommends to use landscape orientation for the reflective facets and increase the ribs angle and the distance between the connecting rings. The methodology presented is robust and can be extended to larger dish diameters.

  12. Parabolic dish reflectors for solar applications approximated by simple surfaces

    OpenAIRE

    Broman, Lars; Broman, Arne

    1996-01-01

    Two different concentrating mirrors have been constructed that resemble parabolic dish reflectors. Both mirrors are made of slightly curved strips of flat, bendable material. The strips of the most simplified mirror have only large-radius circles and straight lines as boundaries. The necessary equations for making the mirrors have been derived. Also a simple way to make a stiff, lightweight frame and support for the mirror strips has been developed. Models of the mirrors have been built and s...

  13. Irrigation market for solar-thermal parabolic-dish systems

    Energy Technology Data Exchange (ETDEWEB)

    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. A 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. Results indicate that the near-term market for such systems depends not only on the type of crop and method of irrigation, but also on the optimal utilization of each added module, which in turn depends on the price of conventional fuel, real discount rate, marginal cost of the solar thermal power system, local insolation level and parabolic dish system efficiency. The study concludes that the potential market size for onfarm-pumped irrigation applications ranges from 101,000 modules when a 14% real discount rate is assumed to 220,000 modules when the real discount rate drops to 8%. Arizona, Kansas, Nebraska, New Mexico and Texas account for 98% of the total demand for this application, with the natural gas replacement market accounting for the largest segment (71%) of the total market.

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

    Energy Technology Data Exchange (ETDEWEB)

    None

    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.

  15. Secondary concentrators for parabolic dish solar thermal power systems

    Science.gov (United States)

    Jaffe, L. D.; Poon, P. T.

    1981-01-01

    A variety of different concepts are currently being studied with the objective to lower the cost of parabolic mirrors and to provide alternatives. One of the considered approaches involves the use of compound concentrators. A compound solar concentrator is a concentrator in which the sunlight is reflected or refracted more than once. It consists of a primary mirror or lens, whose aperture determines the amount of sunlight gathered, and a smaller secondary mirror or lens. Additional small optical elements may also be incorporated. The possibilities and problems regarding a use of compound concentrators in parabolic dish systems are discussed. Attention is given to concentrating secondary lenses, secondary imaging and concentrating mirrors, conical secondary mirrors, compound elliptic secondary concentrating mirrors, and hyperbolic trumpet secondary concentrating mirrors.

  16. Test results on parabolic dish concentrators for solar thermal power systems

    Science.gov (United States)

    Jaffe, Leonard D.

    1989-01-01

    This paper presents results of development testing of various solar thermal parabolic dish concentrators. The concentrators were mostly designed for the production of electric power using dish-mounted Rankine, Brayton or Stirling cycle engines, intended to be produced at low cost. Measured performance for various dishes included optical efficiencies ranging from 0.32 to 0.86 at a geometric concentration ratio of 500, and from about 0.09 to 0.85 at a geometric concentration ratio of 3000. Some malfunctions were observed. The tests should provide operating information of value in developing concentrators with improved performance and reduced maintenance.

  17. Test results on parabolic dish concentrators for solar thermal power systems

    Science.gov (United States)

    Jaffe, Leonard D.

    1989-01-01

    This paper presents results of development testing of various solar thermal parabolic dish concentrators. The concentrators were mostly designed for the production of electric power using dish-mounted Rankine, Brayton or Stirling cycle engines, intended to be produced at low cost. Measured performance for various dishes included optical efficiencies ranging from 0.32 to 0.86 at a geometric concentration ratio of 500, and from about 0.09 to 0.85 at a geometric concentration ratio of 3000. Some malfunctions were observed. The tests should provide operating information of value in developing concentrators with improved performance and reduced maintenance.

  18. Thermal buffering of receivers for parabolic dish solar thermal power plants

    Science.gov (United States)

    Manvi, R.; Fujita, T.; Gajanana, B. C.; Marcus, C. J.

    1980-01-01

    A parabolic dish solar thermal power plant comprises a field of parabolic dish power modules where each module is composed of a two-axis tracking parabolic dish concentrator which reflects sunlight (insolation) into the aperture of a cavity receiver at the focal point of the dish. The heat generated by the solar flux entering the receiver is removed by a heat transfer fluid. In the dish power module, this heat is used to drive a small heat engine/generator assembly which is directly connected to the cavity receiver at the focal point. A computer analysis is performed to assess the thermal buffering characteristics of receivers containing sensible and latent heat thermal energy storage. Parametric variations of the thermal inertia of the integrated receiver-buffer storage systems coupled with different fluid flow rate control strategies are carried out to delineate the effect of buffer storage, the transient response of the receiver-storage systems and corresponding fluid outlet temperature. It is concluded that addition of phase change buffer storage will substantially improve system operational characteristics during periods of rapidly fluctuating insolation due to cloud passage.

  19. Optical analysis and performance evaluation of a solar parabolic dish concentrator

    Directory of Open Access Journals (Sweden)

    Pavlović Saša R.

    2016-01-01

    Full Text Available In this study, the optical design of a solar parabolic dish concentrator is presented. The parabolic dish concentrator consists from 11 curvilinear trapezoidal reflective petals made of polymethyl methacrylate with special reflective coating. The dish diameter is equal to 3.8 m and the theoretical focal point distance is 2.26 m. Numerical simulations are made with the commercial software TracePro from Lambda Research, USA, and the final optimum position between absorber and reflector was calculated to 2.075 m; lower than focus distance. This paper presents results for the optimum position and the optimum diameter of the receiver. The decision for selecting these parameters is based on the calculation of the total flux over the flat and corrugated pipe receiver surface; in its central region and in the peripheral region. The simulation results could be useful reference for designing and optimizing of solar parabolic dish concentrators as for as for CFD analysis, heat transfer and fluid flow analysis in corrugated spiral heat absorbers. [Projekat Ministarstva nauke Republike Srbije, br. III42006: Research and development of energy and environmentally highly effective polygeneration systems based on renewable energy resources i br. III45016: Fabrication and characterization of nanophotonic functional structures in biomedicine and informatics

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

    Science.gov (United States)

    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.

  1. Design and Fabrication of a Two Axis Parabolic Solar Dish Collector

    Directory of Open Access Journals (Sweden)

    Prof. Sonal C Yogi

    2014-11-01

    Full Text Available The work consists of the design of the chain drive system and the fabrication of the two axis parabolic solar dish. It is a model study of the two axis parabolic dish which worked by the automatic circuit that was developed. Ready made parabolic solar dish is taken and fabricated. The circular iron ring provides the two axis motion of the dish. A compound chain drive system was developed for the smooth movement of the dish. An electromechanical system which tracks the sun on both axes and which is controlled via a programmable logic control (PLC was designed and implemented. In this a theoretical study was done. A C program was made which gave the required result for the graphical representation of the recorded radiation. Programmable Logic Controls (PLC was used instead of photo sensors, which are widely used for tracking the sun. The azimuthal angle of the sun from sunrise to sunset times was calculated for each day of the year at 23.59 Lat & 72.38Longitude in the Northern hemisphere, the location of the city Mehsana. According to this azimuth angle, the required analog signal was taken from the PLC analog module and sent to the power window motor, which controlled the position of the panel to ensure that the rays fall vertically on the panel. After the mechanical control of the system was started, the performance measurements of the solar panel were carried out. The values obtained from the measurements were compared and the necessary evaluations were conducted.

  2. Slope Measurements of Parabolic Dish Concentrators Using Color-Coded Targets

    Energy Technology Data Exchange (ETDEWEB)

    Ulmer, S.; Heller, P.; Reinalter, W.

    2006-07-01

    A new short, yet highly accurate method for measuring the slope errors of parabolic dish concentrators has been developed. This method uses a flat target with colored stripes that is placed close to the focal plane and a digital camera located at an observation point on the optical axis at some distance from it. A specially developed image analysis algorithm detects the different colors in the images of the reflection of the target in the concentrator and assigns them their known position on the color target. This information, along with the geometric relationship between the components of the measurement setup and the theoretical parabolic shape of the concentrator, is used to calculate the normal vectors of the concentrator surface. From these normal vectors the radial and tangential slopes can be calculated and compared to the design values of the concentrator. The resulting slope errors not only give the total concentrator error for general characterization of the dish, but also indicate systematic errors in fabrication and mounting with high spatial resolution. In order to verify the quality of the results obtained, a ray-tracing code was developed that calculates the flux distribution on planes perpendicular to the optical axis. Measured slope errors of a DISTAL-2 dish concentrator are presented and the calculated flux distributions are compared to measured flux distributions. The comparison shows excellent agreement in the flux distribution on the absorber plane. This verifies the promising potential of this method for fast, highly precise measurement of imperfections in dish concentrator shape. (Author)

  3. Cost/performance of solar reflective surfaces for parabolic dish concentrators

    Science.gov (United States)

    Bouquet, F.

    1980-01-01

    Materials for highly reflective surfaces for use in parabolic dish solar concentrators are discussed. Some important factors concerning performance of the mirrors are summarized, and typical costs are treated briefly. Capital investment cost/performance ratios for various materials are computed specifically for the double curvature parabolic concentrators using a mathematical model. The results are given in terms of initial investment cost for reflective surfaces per thermal kilowatt delivered to the receiver cavity for various operating temperatures from 400 to 1400 C. Although second surface glass mirrors are emphasized, first surface, chemically brightened and anodized aluminum surfaces as well as second surface, metallized polymeric films are treated. Conventional glass mirrors have the lowest cost/performance ratios, followed closely by aluminum reflectors. Ranges in the data due to uncertainties in cost and mirror reflectance factors are given.

  4. Analysis of solar water heater with parabolic dish concentrator and conical absorber

    Science.gov (United States)

    Rajamohan, G.; Kumar, P.; Anwar, M.; Mohanraj, T.

    2017-06-01

    This research focuses on developing novel technique for a solar water heating system. The novel solar system comprises a parabolic dish concentrator, conical absorber and water heater. In this system, the conical absorber tube directly absorbs solar radiation from the sun and the parabolic dish concentrator reflects the solar radiations towards the conical absorber tube from all directions, therefore both radiations would significantly improve the thermal collector efficiency. The working fluid water is stored at the bottom of the absorber tubes. The absorber tubes get heated and increases the temperature of the working fluid inside of the absorber tube and causes the working fluid to partially evaporate. The partially vaporized working fluid moves in the upward direction due to buoyancy effect and enters the heat exchanger. When fresh water passes through the heat exchanger, temperature of the vapour decreases through heat exchange. This leads to condensation of the vapour and forms liquid phase. The working fluid returns to the bottom of the collector absorber tube by gravity. Hence, this will continue as a cyclic process inside the system. The proposed investigation shows an improvement of collector efficiency, enhanced heat transfer and a quality water heating system.

  5. Large Parabolic Dish collectors with small gas-turbine, Stirling engine or photovoltaic power conversion systems

    Energy Technology Data Exchange (ETDEWEB)

    Gehlisch, K.; Heikal, H.; Mobarak, A.; Simon, M.

    1982-08-01

    A comparison for different solar thermal power plants is presented and demonstrates that the large parabolic dish in association with a gas turbine or a Sterling engine could be a competitive system design in the net power range of 50-1000KW. The important advantages of the Large Parabolic Dish concept compared to the Farm and Tower concept are discussed: concentration ratios up to 5000 and uniform heat flux distribution throughout the day which allow very high receiver temperatures and therefor high receiver efficiency to operate effectively Stirling motors or small gas turbines in the mentioned power range with an overall efficiency of 20 to 30%. The high focal plane concentration leads to the efficient use of ceramic materials for receivers of the next generation, applicable in temperature ranges up to 1,300 /sup 0/C for energy converters. Besides the production of electricity, the system can supply process heat in the temperature range of 100 to 400 /sup 0/C as waste heat from the gas turbo converter and heat at temperature levels from 500 to 900 /sup 0/C (1300 /sup 0/C) directly out of the receiver.

  6. A review of test results on parabolic dish solar thermal power modules with dish-mounted Rankine engines and for production of process steam

    Science.gov (United States)

    Jaffe, Leonard D.

    1988-01-01

    This paper presents results of development testing of various solar thermal parabolic dish modules and assemblies. Most of the tests were at modules and assemblies that used a dish-mounted, organic Rankine cycle turbine for production of electric power. Some tests were also run on equipment for production of process steam or for production of electricity using dish-mounted reciprocating steam engines. These tests indicate that early modules achieve efficiencies of about 18 percent in converting sunlight to electricity (excluding the inverter but including parasitics). A number of malfunctions occurred. The performance measurements, as well as the malfunctions and other operating experience, provided information that should be of value in developing systems with improved performance and reduced maintenance.

  7. Solar reforming of methane in a direct absorption catalytic reactor on a parabolic dish

    Energy Technology Data Exchange (ETDEWEB)

    Muir, J.F.; Hogan, R.E. Jr.; Skocypec, R.D. (Sandia National Labs., Albuquerque, NM (USA)); Buck, R. (Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Stuttgart (Germany, F.R.). Inst. fuer Technische Thermodynamik)

    1990-01-01

    The concept of solar driven chemical reactions in a commercial-scale volumetric receiver/reactor on a parabolic concentrator was successfully demonstrated in the CAtalytically Enhanced Solar Absorption Receiver (CAESAR) test. Solar reforming of methane (CH{sub 4}) with carbon dioxide (CO{sub 2}) was achieved in a 64-cm diameter direct absorption reactor on a parabolic dish capable of 150 kW solar power. The reactor was a catalytic volumetric absorber consisting of a multi-layered, porous alumina foam disk coated with rhodium (Rh) catalyst. The system was operated during both steady-state and solar transient (cloud passage) conditions. The total solar power absorbed reached values up to 97 kW and the maximum methane conversion was 70%. Receiver thermal efficiencies ranged up to 85% and chemical efficiencies peaked at 54%. The absorber performed satisfactorily in promoting the reforming reaction during the tests without carbon formation. However, problems of cracking and degradation of the porous matrix, nonuniform dispersion of the Rh through the absorber, and catalyst deactivation due to sintering and possible encapsulation, must be resolved to achieve long-term operation and eventual commercialization. 17 refs., 11 figs., 1 tab.

  8. Prediction and optimization of the performance of parabolic solar dish concentrator with sphere receiver using analytical function

    CERN Document Server

    Huang, Weidong; Hu, Peng; Chen, Zeshao

    2011-01-01

    Parabolic solar dish concentrator with sphere receiver is less studied. We present an analytic function to calculate the intercept factor of the system with real sun bright distribution and Gaussian distribution, the results indicate that the intercept factor is related to the rim angle of reflector and the ratio of open angle of receiver at the top of reflector to optical error when the optical error is larger than or equal to 5 mrad, but is related to the rim angle, open angle and optical error in less than 5 mrad optical error. Furthermore we propose a quick process to optimize the system to provide the maximum solar energy to net heat efficiency for different optical error under typical condition. The results indicate that the parabolic solar dish concentrator with sphere receiver has rather high solar energy to net heat efficiency which is 20% more than solar trough and tower system including higher cosine factor and lower heat loss of the receiver.

  9. Comparison of advanced thermal and electrical storage for parabolic dish solar thermal power systems

    Science.gov (United States)

    Fujita, T.; Birur, G. C.; Schredder, J. M.; Bowyer, J. M.; Awaya, H. I.

    1982-01-01

    Parabolic dish solar concentrator cluster concepts are explored, with attention given to thermal storage systems coupled to Stirling and Brayton cycle power conversion devices. Sensible heat storage involving molten salt (NaOH), liquid sodium, and solid cordierite bricks are considered for 1500 F thermal storage systems. Latent heat storage with NaF-MgF2 phase change materials are explored in terms of passive, active, and direct contact designs. Comparisons are made of the effectiveness of thermal storage relative to redox, Na-S, Zn-Cl, and Zn-Br battery storage systems. Molten lead trickling down through a phase change eutectic, the NaF-MgF2, formed the direct contact system. Heat transport in all systems is effected through Inconel pipes. Using a cost goal of 120-150 mills/kWh as the controlling parameter, sensible heat systems with molten salts transport with either Stirling or Brayton engines, or latent heat systems with Stirling engines, and latent heat-Brayton engine with direct contact were favored in the analyses. Battery storage systems, however, offered the most flexibility of applications.

  10. Charging studies of heat packs using parabolic dish solar energy concentrator for extreme conditions

    Science.gov (United States)

    Kumar, Rohitash; Vyas, Sumita; Kumar, Ravindra; Dixit, Ambesh

    2016-05-01

    Parabolic dish solar energy concentrator with aperture diameter 1.4 m and focal length 0.32 m is designed and fabricated to charge and store solar thermal energy in phase change material (PCM) based heat packs. Overall heat loss factor, heat duty, over all thermal efficiency, and optical efficiency factor are calculated using water sensible heating and cooling tests and values are 16.11 W m-2 K-1, 546.9 W, 49.2% and 0.62 respectively. The performance characteristic curve is generated using these parameters to understand its performance at different ambient temperatures and solar insolation. The fabricated concentrator has been used to charge 16 PCM heat packs with 150 g PCM in each heat pack, which took about 35 minutes for complete charging of PCM heat packs at average ambient temperature 39 °C and solar radiation flux density 715 W m-2 K-1. The charged heat packs are subjected to discharge studies at average ambient temperature about - 7 °C and observed heat release in the temperature range of 48 to 40 °C for 50 minutes, suggesting its applications for comfort and therapeutic applications in high altitude areas.

  11. Secondary and compound concentrators for parabolic dish solar thermal power systems

    Science.gov (United States)

    Jaffe, L. D.; Poon, P. T.

    1981-01-01

    A secondary optical element may be added to a parabolic dish solar concentrator to increase the geometric concentration ratio attainable at a given intercept factor. This secondary may be a Fresnel lens or a mirror, such as a compound elliptic concentrator or a hyperbolic trumpet. At a fixed intercept factor, higher overall geometric concentration may be obtainable with a long focal length primary and a suitable secondary matched to it. Use of a secondary to increase the geometric concentration ratio is more likely to e worthwhile if the receiver temperature is high and if errors in the primary are large. Folding the optical path with a secondary may reduce cost by locating the receiver and power conversion equipment closer to the ground and by eliminating the heavy structure needed to support this equipment at the primary focus. Promising folded-path configurations include the Ritchey-Chretien and perhaps some three element geometries. Folding the optical path may be most useful in systems that provide process heat.

  12. Comparison of advanced thermal and electrical storage for parabolic dish solar thermal power systems

    Science.gov (United States)

    Fujita, T.; Birur, G. C.; Schredder, J. M.; Bowyer, J. M.; Awaya, H. I.

    Parabolic dish solar concentrator cluster concepts are explored, with attention given to thermal storage systems coupled to Stirling and Brayton cycle power conversion devices. Sensible heat storage involving molten salt (NaOH), liquid sodium, and solid cordierite bricks are considered for 1500 F thermal storage systems. Latent heat storage with NaF-MgF2 phase change materials are explored in terms of passive, active, and direct contact designs. Comparisons are made of the effectiveness of thermal storage relative to redox, Na-S, Zn-Cl, and Zn-Br battery storage systems. Molten lead trickling down through a phase change eutectic, the NaF-MgF2, formed the direct contact system. Heat transport in all systems is effected through Inconel pipes. Using a cost goal of 120-150 mills/kWh as the controlling parameter, sensible heat systems with molten salts transport with either Stirling or Brayton engines, or latent heat systems with Stirling engines, and latent heat-Brayton engine with direct contact were favored in the analyses. Battery storage systems, however, offered the most flexibility of applications.

  13. Secondary and compound concentrators for parabolic-dish solar-thermal power systems

    Energy Technology Data Exchange (ETDEWEB)

    Jaffe, L.D.; Poon, P.T.

    1981-04-15

    A secondary optical element may be added to a parabolic dish solar concentrator to increase the geometric concentration ratio attainable at a given intercept factor. This secondary may be a Fresnel lens or a mirror, such as a compound elliptic concentrator or a hyperbolic trumpet. At a fixed intercept factor, higher overall geometric concentration may be obtainable with a long focal length primary and a suitable secondary matched to it. Use of a secondary to increase the geometric concentration ratio is more likely to be worthwhile if the receiver temperature is high and if errors in the primary are large. Folding the optical path with a secondary may reduce cost by locating the receiver and power conversion equipment closer to the ground and by eliminating the heavy structure needed to support this equipment at the primary focus. Promising folded-path configurations include the Ritchey-Chretien and perhaps some three-element geometries. Folding the optical path may be most useful in systems that provide process heat.

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

    Science.gov (United States)

    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.

  15. Dish/stirling hybrid-receiver

    Science.gov (United States)

    Mehos, Mark S.; Anselmo, Kenneth M.; Moreno, James B.; Andraka, Charles E.; Rawlinson, K. Scott; Corey, John; Bohn, Mark S.

    2002-01-01

    A hybrid high-temperature solar receiver is provided which comprises a solar heat-pipe-receiver including a front dome having a solar absorber surface for receiving concentrated solar energy, a heat pipe wick, a rear dome, a sidewall joining the front and the rear dome, and a vapor and a return liquid tube connecting to an engine, and a fossil fuel fired combustion system in radial integration with the sidewall for simultaneous operation with the solar heat pipe receiver, the combustion system comprising an air and fuel pre-mixer, an outer cooling jacket for tangentially introducing and cooling the mixture, a recuperator for preheating the mixture, a burner plenum having an inner and an outer wall, a porous cylindrical metal matrix burner firing radially inward facing a sodium vapor sink, the mixture ignited downstream of the matrix forming combustion products, an exhaust plenum, a fossil-fuel heat-input surface having an outer surface covered with a pin-fin array, the combustion products flowing through the array to give up additional heat to the receiver, and an inner surface covered with an extension of the heat-pipe wick, a pin-fin shroud sealed to the burner and exhaust plenums, an end seal, a flue-gas diversion tube and a flue-gas valve for use at off-design conditions to limit the temperature of the pre-heated air and fuel mixture, preventing pre-ignition.

  16. Performance tests and efficiency analysis of Solar Invictus 53S - A parabolic dish solar collector for direct steam generation

    Science.gov (United States)

    Jamil, Umer; Ali, Wajahat

    2016-05-01

    This paper presents the results of performance tests conducted on Solar Invictus 53S `system'; an economically effective solar steam generation solution designed and developed by ZED Solar Ltd. The system consists of a dual axis tracking parabolic solar dish and bespoke cavity type receiver, which works as a Once Through Solar Steam Generator `OTSSG' mounted at the focal point of the dish. The overall performance and efficiency of the system depends primarily on the optical efficiency of the solar dish and thermal efficiency of the OTSSG. Optical testing performed include `on sun' tests using CCD camera images and `burn plate' testing to evaluate the sunspot for size and quality. The intercept factor was calculated using a colour look-back method to determine the percentage of solar rays focused into the receiver. Solar dish tracking stability tests were carried out at different times of day to account for varying dish elevation angles and positions, movement of the sunspot centroid was recorded and logged using a CCD camera. Finally the overall performance and net solar to steam efficiency of the system was calculated by experimentally measuring the output steam parameters at varying Direct Normal Insolation (DNI) levels at ZED Solar's test facility in Lahore, Pakistan. Thermal losses from OTSSG were calculated using the known optical efficiency and measured changes in output steam enthalpy.

  17. Comparison of advanced engines for parabolic dish solar thermal power plants

    Science.gov (United States)

    Fujita, T.; Bowyer, J. M.; Gajanana, B. C.

    1980-01-01

    A paraboloidal dish solar thermal power plant produces electrical energy by a two-step conversion process. The collector subsystem is composed of a two-axis tracking paraboloidal concentrator and a cavity receiver. The concentrator focuses intercepted sunlight (direct, normal insolation) into a cavity receiver whose aperture encircles the focal point of the concentrator. At the internal wall of the receiver the electromagnetic radiation is converted to thermal energy. A heat engine/generator assembly then converts the thermal energy captured by the receiver to electricity. Developmental activity has been concentrated on small power modules which employ 11- to 12-meter diameter dishes to generate nominal power levels of approximately 20 kWe. A comparison of advanced heat engines for the dish power module is presented in terms of the performance potential of each engine with its requirements for advanced technology development. Three advanced engine possibilities are the Brayton (gas turbine), Brayton/Rankine combined cycle, and Stirling engines.

  18. Optical analysis of parabolic dish concentrators for solar dynamic power systems in space

    Science.gov (United States)

    Jefferies, K. S.

    1985-01-01

    An optical analysis of a parabolic solar collection system operating in Earth orbit was performed using ray tracing techniques. The analysis included the effects of: (1) solar limb darkening, (2) parametric variation of mirror surface error, (3) parametric variation of mirror rim angle, and (4) parametric variation of alignment and pointing error. This ray tracing technique used numerical integration to combine the effects of rays emanating from different parts of the sun at different intensities with the effects of normally distributed mirror-surface errors to compute the angular intensity distribution of rays leaving the mirror surface. A second numerical integration was then performed over the surface of the parabolic mirror to compute the radial distribution of brightness at the mirror focus. Major results of the analysis included: (1) solar energy can be collected at high temperatures with high efficiency, (2) higher absorber temperatures can be achieved at lower efficiencies, or higher efficiencies can be achieved at lower temperatures, and (3) collection efficiency is near its maximum level across a broad plateau of rim angles from 40 deg to 70 deg.

  19. Manufacturing cost analysis of a parabolic dish concentrator (General Electric design) for solar thermal electric power systems in selected production volumes

    Science.gov (United States)

    1981-01-01

    The manufacturing cost of a General Electric 12 meter diameter concentrator was estimated. This parabolic dish concentrator for solar thermal system was costed in annual production volumes of 100 - 1,000 - 5,000 - 10,000 - 50,000 100,000 - 400,000 and 1,000,000 units. Presented for each volume are the costs of direct labor, material, burden, tooling, capital equipment and buildings. Also presented is the direct labor personnel and factory space requirements. All costs are based on early 1981 economics.

  20. Solar-parabolic dish-Stirling-engine-system module. Task 1: Topical report, market assessment/conceptual design

    Energy Technology Data Exchange (ETDEWEB)

    1982-11-30

    The major activities reported are: a market study to identify an early market for a dish-Stirling module and assess its commercial potential; preparation of a conceptual system and subsystem design to address this market; and preparation of an early sales implementation plan. A study of the reliability of protection from the effects of walk-off, wherein the sun's image leaves the receiver if the dish is not tracking, is appended, along with an optical analysis and structural analysis. Also appended are the relationship between PURPA and solar thermal energy development and electric utility pricing rationale. (LEW)

  1. Solar-parabolic dish-Stirling-engine-system module. Task 1: Topical report, market assessment/conceptual design

    Energy Technology Data Exchange (ETDEWEB)

    1982-11-30

    The major activities reported are: a market study to identify an early market for a dish-Stirling module and assess its commercial potential; preparation of a conceptual system and subsystem design to address this market; and preparation of an early sales implementation plan. A study of the reliability of protection from the effects of walk-off, wherein the sun's image leaves the receiver if the dish is not tracking, is appended, along with an optical analysis and structural analysis. Also appended are the relationship between PURPA and solar thermal energy development and electric utility pricing rationale. (LEW)

  2. The CAESAR project: Experimental and modeling investigations of methane reforming in a CAtalytically Enhanced Solar Absorption Receiver on a parabolic dish

    Energy Technology Data Exchange (ETDEWEB)

    Muir, J.F.; Hogan, R.E. Jr.; Skocypec, R.D. [Sandia National Labs., Albuquerque, NM (US); Buck, R. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt, Stuttgart (DE). Inst. of Technical Thermodynamics

    1993-07-01

    A joint US/Federal Republic of Germany (FRG) project has successfully tested a unique solar-driven chemical reactor in the CAtalytically Enhanced Solar Absorption Receiver (CAESAR) experiment. The CAESAR test was a {open_quotes}proof-of-concept{close_quotes} demonstration of carbon-dioxide reforming of methane in a commercial-scale, solar, volumetric receiver/reactor on a parabolic dish concentrator. The CAESAR design; test facility and instrumentation; thermal and chemical tests; and analysis of test results are presented in detail. Numerical models for the absorber and the receiver are developed and predicted performance is compared with test data. Post test analyses to assess the structural condition of the absorber and the effectiveness of the rhodium catalyst are presented. Unresolved technical issues are identified and future development efforts are recommended.

  3. Distillate yield improvement using a parabolic dish reflector coupled single slope basin solar still with thermal energy storage using beeswax

    Directory of Open Access Journals (Sweden)

    Aondoyila KUHE

    2016-07-01

    Full Text Available A single slope solar still, integrated with latent heat thermal energy storage system coupled to a parabolic concentrator was designed with the aim of improving productivity. 14 kg of beeswax was used as phase change material (PCM between the absorber plate and the bottom of the still to keep the operating temperature of the still high enough to produce distilled water even during the sunset hours. The bottom of the still is covered by 0.2 m aluminum sheet painted black on the side facing the parabolic concentrator to help in absorbing solar radiation reflected from the parabolic concentrator and conducting same to the PCM. To determine the effect of PCM, a solar still without PCM was used to compare with the solar still with PCM. The temperature of water, air temperature, inner surface glass temperature and outer surface glass temperature were measured. Experimental results show that the effect of thermal storage in the parabolic concentrator-coupled single slope solar still increased the productivity by 62%.

  4. Accelerated parabolic Radon domain 2D adaptive multiple subtraction with fast iterative shrinkage thresholding algorithm and its application in parabolic Radon domain hybrid demultiple method

    Science.gov (United States)

    Li, Zhong-xiao; Li, Zhen-chun

    2017-08-01

    Adaptive multiple subtraction is an important step for successfully conducting surface-related multiple elimination in marine seismic exploration. 2D adaptive multiple subtraction conducted in the parabolic Radon domain has been proposed to better separate primaries and multiples than 2D adaptive multiple subtraction conducted in the time-offset domain. Additionally, the parabolic Radon domain hybrid demultiple method combining parabolic Radon filtering and parabolic Radon domain 2D adaptive multiple subtraction can better remove multiples than the cascaded demultiple method using time-offset domain 2D adaptive multiple subtraction and the parabolic Radon transform method sequentially. To solve the matching filter in the optimization problem with L1 norm minimization constraint of primaries, traditional parabolic Radon domain 2D adaptive multiple subtraction uses the iterative reweighted least squares (IRLS) algorithm, which is computationally expensive for solving a weighted LS inversion in each iteration. In this paper we introduce the fast iterative shrinkage thresholding algorithm (FISTA) as a faster alternative to the IRLS algorithm for parabolic Radon domain 2D adaptive multiple subtraction. FISTA uses the shrinkage-thresholding operator to promote the sparsity of estimated primaries and solves the 2D matching filter with iterative steps. FISTA based parabolic Radon domain 2D adaptive multiple subtraction reduces the computation time effectively while achieving similar accuracy compared with IRLS based parabolic Radon domain 2D adaptive multiple subtraction. Additionally, the provided examples show that FISTA based parabolic Radon domain 2D adaptive multiple subtraction can better separate primaries and multiples than FISTA based time-offset domain 2D adaptive multiple subtraction. Furthermore, we introduce FISTA based parabolic Radon domain 2D adaptive multiple subtraction into the parabolic Radon domain hybrid demultiple method to improve its computation

  5. Efficient parabolic evaluation of coupling terms in hybrid quantum/classical simulations

    Energy Technology Data Exchange (ETDEWEB)

    Bastida, Adolfo, E-mail: bastida@um.es [Departamento de Quimica Fisica, Facultad de Quimica, Universidad de Murcia, 30100 Murcia (Spain); Soler, Miguel Angel; Zuniga, Jose; Requena, Alberto [Departamento de Quimica Fisica, Facultad de Quimica, Universidad de Murcia, 30100 Murcia (Spain); Miguel, Beatriz [Departamento de Ingenieria Quimica y Ambiental, Universidad Politecnica de Cartagena, 30203 Cartagena (Spain)

    2009-03-30

    A parabolic interpolation function of time is proposed to evaluate the non-adiabatic coupling matrix elements and the adiabatic energies at intermediate times within the classical time integration interval in hybrid quantum/classical simulations. The accuracy and the computational efficiency of this parabolic approximation are illustrated by carrying out a numerical application to the well-studied vibrational relaxation of I{sub 2} in liquid xenon.

  6. Self-similar evolutions of parabolic, Hermite-Gaussian, and hybrid optical pulses: Universality and diversity.

    Science.gov (United States)

    Chen, Shihua; Yi, Lin; Guo, Dong-Sheng; Lu, Peixiang

    2005-07-01

    Three novel types of self-similar solutions, termed parabolic, Hermite-Gaussian, and hybrid pulses, of the generalized nonlinear Schrödinger equation with varying dispersion, nonlinearity, and gain or absorption are obtained. The properties of the self-similar evolutions in various nonlinear media are confirmed by numerical simulations. Despite the diversity of their formations, these self-similar pulses exhibit many universal features which can facilitate significantly the achievement of well-defined linearly chirped output pulses from an optical fiber, an amplifier, or an absorption medium, under certain parametric conditions. The other intrinsic characteristics of each type of self-similar pulses are also discussed.

  7. Parabolic-like maps

    CERN Document Server

    Lomonaco, Luciana Luna Anna

    2011-01-01

    In this paper we introduce the notion of parabolic-like mapping, which is an object similar to a polynomial-like mapping, but with a parabolic external class, i.e. an external map with a parabolic fixed point. We prove a straightening theorem for parabolic-like maps, which states that any parabolic-like map of degree 2 is hybrid conjugate to a member of the family Per_1(1), and this member is unique (up to holomorphic conjugacy) if the filled Julia set of the parabolic-like map is connected.

  8. Optimization of woven jute/glass fibre-reinforced polyester hybrid composite solar parabolic trough collector

    Science.gov (United States)

    Reddy, K. S.; Singla, Hitesh

    2017-07-01

    In the present work, structural analysis of 5.77m × 4m woven jute (J)/glass (G) fibre-reinforced polyester hybrid composite solar parabolic trough is carried out based on trough parameters to obtain the minimum RMS local slope deviation, termed as SDx value under gravity loading. The optimization is done by varying parameters viz. direction and size of reinforced conduits, stacking number and sequence of hybrid trough laminate at fibre orientation of Δθ=45° and Δθ=60° amongst the layers at 0° collector angle. The analysis revealed that the configuration in which the conduits are placed in both X and Y directions is preferred over other configurations to scale down the effect of wind loads. Furthermore it has been observed that laminate of the order [0°G/45°G/-45°J/90°J]s undergoes minimum surface deformation amongst all the other configurations at conduit reinforcement in both X and Y directions for a conduit thickness of 0.75 mm and radius of 10 mm and obtains the overall SDx value of 1.3492 mrad. The results shows that proposed trough model is very promising and evolves a cost effective system.

  9. Fish Dishes.

    Science.gov (United States)

    Derby, Marie

    2003-01-01

    Describes an art project that was inspired by Greek pottery, specifically dishes shaped as fish. Explains that fourth-grade students drew a fish shape that was later used to create their clay version of the fish. Discusses how the students examined the pottery to make decisions about color and design. (CMK)

  10. Fuse Protects Parabolic-Dish Solar Collector

    Science.gov (United States)

    Selcuk, M. K.

    1983-01-01

    Sliding barrel and shutter protect against overheating. Downward movement of shutter initiated by melting of fuse wire that suspends it. Shutter lowered or raised under operator's control by depressuring or pressurizing hydraulic cylinder.

  11. Annual measured and simulated thermal performance analysis of a hybrid solar district heating plant with flat plate collectors and parabolic trough collectors in series

    DEFF Research Database (Denmark)

    Tian, Zhiyong; Perers, Bengt; Furbo, Simon

    2017-01-01

    in large solar heating plants for a district heating network, a hybrid solar collector field with 5960 m2 flat plate collectors and 4039 m2 parabolic trough collectors in series was constructed in Taars, Denmark. The design principle is that the flat plate collectors preheat the return water from...... for this type of hybrid solar district heating plants with flat plate collectors and parabolic trough collectors in the Nordic region, but also introduce a novel design concept of solar district heating plants to other high solar radiation areas.......Flat plate collectors have relatively low efficiency at the typical supply temperatures of district heating networks (70–95 °C). Parabolic trough collectors retain their high efficiency at these temperatures. To maximize the advantages of flat plate collectors and parabolic trough collectors...

  12. Research on beam characteristics in a large-Fresnel-number unstable-waveguide hybrid resonator with parabolic mirrors.

    Science.gov (United States)

    Wang, Wei; Qin, Yingxiong; Xiao, Yu; Zhong, Lijing; Wu, Chao; Wang, Zhen; Wan, Wen; Tang, Xiahui

    2016-07-20

    Large-Fresnel-number unstable-waveguide hybrid resonators employing spherical resonator mirrors suffer from spherical aberration, which adversely affects beam quality and alignment sensitivity. In this paper, we present experimental and numerical wave-optics simulations of the beam characteristics of a negative-branch hybrid resonator having parabolic mirrors with a large equivalent Fresnel number in the unstable direction. These results are compared with a resonator using spherical mirrors. Using parabolic mirrors, the output beam has a smaller beam spot size and higher power density at the focal plane. We found that the power extraction efficiency is 3.5% higher when compared with a resonator using spherical mirrors as the cavity length was varied between -1 and 1 mm from the ideal confocal resonator. In addition, the power extraction efficiency is 5.6% higher for mirror tilt angles varied between -6 and 6 mrad. Furthermore, the output propagating field is similar to a converging wave for a spherical mirror resonator and the output beam direction deviates 3.5 mrad from the optical axis. The simulation results are in good agreement with the experimental results.

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

    Science.gov (United States)

    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.

  14. Activity and accomplishments of dish/Stirling electric power system development

    Science.gov (United States)

    Livingston, F. R.

    1985-01-01

    The development of the solar parabolic-dish/Stirling-engine electricity generating plant known as the dish/Stirling electric power system is described. The dish/Stirling electric power system converts sunlight to electricity more efficiently than any known existing solar electric power system. The fabrication and characterization of the test bed concentrators that were used for Stirling module testing and of the development of parabolic dish concentrator No. 2, an advanced solar concentrator unit considered for use with the Stirling power conversion unit is discussed.

  15. Rigid collapsible dish structure

    Science.gov (United States)

    Palmer, William B. (Inventor); Giebler, Martin M. (Inventor)

    1982-01-01

    A collapsible dish structure composed of a plurality of rows of rigid radial petal assemblies concentric with the axis of the dish. The petal assemblies consist of a center petal and two side petals, the center petal hinged on an axis tangent to a circle concentric with the axis of the dish and the side petals hinged to the center petal at their mating edge. The center petal is foldable inwardly and the side petals rotate about their hinges such that the collapsed dish structure occupies a much smaller volume than the deployed dish. Means of controlling the shape of the dish to compensate for differential expansion of the deployed dish are also provided.

  16. The planar parabolic optical antenna.

    Science.gov (United States)

    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.

  17. Parabolic Flight Investigation for Advanced Exercise Concept Hardware Hybrid Ultimate Lifting Kit (HULK)

    Science.gov (United States)

    Weaver, A. S.; Funk, J. H.; Funk, N. W.; Sheehan, C. C.; Humphreys, B. T.; Perusek, G. P.

    2015-01-01

    Long-duration space flight poses many hazards to the health of the crew. Among those hazards is the physiological deconditioning of the musculoskeletal and cardiovascular systems due to prolonged exposure to microgravity. To combat this erosion of physical condition space flight may take on the crew, the Human Research Program (HRP) is charged with developing Advanced Exercise Concepts to maintain astronaut health and fitness during long-term missions, while keeping device mass, power, and volume to a minimum. The goal of this effort is to preserve the physical capability of the crew to perform mission critical tasks in transit and during planetary surface operations. The HULK is a pneumatic-based exercise system, which provides both resistive and aerobic modes to protect against human deconditioning in microgravity. Its design targeted the International Space Station (ISS) Advanced Resistive Exercise Device (ARED) high level performance characteristics and provides up to 600 foot pounds resitive loading with the capability to allow for eccentric to concentric (E:C) ratios of higher than 1:1 through a DC motor assist component. The device's rowing mode allows for high cadence aerobic activity. The HULK parabolic flight campaign, conducted through the NASA Flight Opportunities Program at Ellington Field, resulted in the creation of device specific data sets including low fidelity motion capture, accelerometry and both inline and ground reaction forces. These data provide a critical link in understanding how to vibration isolate the device in both ISS and space transit applications. Secondarily, the study of human exercise and associated body kinematics in microgravity allows for more complete understanding of human to machine interface designs to allow for maximum functionality of the device in microgravity.

  18. Optimization of dish solar collectors

    Science.gov (United States)

    Jaffe, L. D.

    1983-01-01

    Methods for optimizing parabolic dish solar collectors and the consequent effects of various optical, thermal, mechanical, and cost variables are examined. The most important performance optimization is adjusting the receiver aperture to maximize collector efficiency. Other parameters that can be adjusted to optimize efficiency include focal length, and, if a heat engine is used, the receiver temperature. The efficiency maxima associated with focal length and receiver temperature are relatively broad; it may, accordingly, be desirable to design somewhat away from the maxima. Performance optimization is sensitive to the slope and specularity errors of the concentrator. Other optical and thermal variables affecting optimization are the reflectance and blocking factor of the concentrator, the absorptance and losses of the receiver, and, if a heat engine is used, the shape of the engine efficiency versus temperature curve. Performance may sometimes be improved by use of an additional optical element (a secondary concentrator) or a receiver window if the errors of the primary concentrator are large or the receiver temperature is high. Previously announced in STAR as N83-19224

  19. Test and Analysis of an Inflatable Parabolic Dish Antenna

    Science.gov (United States)

    Gaspar, james L.; Sreekantamurthy, Tham; Mann, Troy; Behun, Vaughn; Romanofsky, Robert; Lambert, Kevin; Pearson, James

    2006-01-01

    NASA is developing ultra-lightweight structures technology for large communication antennas for application to space missions. With these goals in mind, SRS Technologies has been funded by NASA Glenn Research Center (GRC) to undertake the development of a subscale ultra-thin membrane inflatable antenna for deep-space applications. One of the research goals is to develop approaches for prediction of the radio frequency and structural characteristics of inflatable and rigidizable membrane antenna structures. GRC has teamed with NASA Langley Research Center (LaRC) to evaluate inflatable and rigidizable antenna concepts for potential space missions. GRC has completed tests to evaluate RF performance, while LaRC completed structural tests and analysis to evaluate the static shape and structural dynamic responses of a laboratory model of a 0.3 meter antenna. This paper presents the details of the tests and analysis completed to evaluate the radio frequency and structural characteristics of the antenna.

  20. The HERA Dish II: Electromagnetic Simulations and Science Implications

    CERN Document Server

    Ewall-Wice, Aaron; DeBoer, David; Hewitt, Jacqueline; Parsons, Aaron; Aguirre, James; Ali, Zaki S; Bowman, Judd; Cheng, Carina; Neben, Abraham R; Patra, Nipanjana; Thyagarajan, Nithyanandan; Venter, Mariet; Acedo, Eloy de Lera; Dillon, Joshua S; Doolittle, Roger; Egan, Dennis; Hendrick, Mike; Klima, Patricia; Kohn, Saul; Schaffner, Patrick; Shelton, John; Saliwanchik, Benjamin; Tegmark, Max; Taylor, H A; Taylor, Rusty; Wirt, Butch

    2016-01-01

    We use time-domain electromagnetic simulations to assess the spectral characteristics of the dish antenna for the Hydrogen Epoch of Reionization Array (HERA). These simulations are part of a multi-faceted campaign to determine the effectiveness of the dish's design for obtaining a detection of redshifted 21 cm emission from the epoch of reionization. Our simulations show the existence of reflections between HERA's suspended feed and its parabolic dish reflector, at certain frequencies, with an amplitude of roughly $ -35$dB at 100 ns which can lead to some loss of measurable modes and a modest reduction in sensitivity. Even in the presence of this structure, we find that the spectral response of the dish is sufficiently smooth for delay filtering, a proven foreground isolation technique, to contain foreground emission at line-of-sight wave numbers below $k_\\parallel \\lesssim 0.2h$Mpc$^{-1}$, in the region where the current PAPER experiment operates. Incorporating these results into a Fisher Matrix analysis, we...

  1. Piecewise-Planar Parabolic Reflectarray Antenna

    Science.gov (United States)

    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.

  2. MODELLING OF AN INEXPENSIVE 9M SATELLITE DISH FROM 3D POINT CLOUDS CAPTURED BY TERRESTRIAL LASER SCANNERS

    Directory of Open Access Journals (Sweden)

    D. Belton

    2012-09-01

    Full Text Available This paper presents the use of Terrestrial laser scanners (TLS to model the surface of satellite dish. In this case, the dish was an inexpensive 9m parabolic satellite dish with a mesh surface, and was to be utilised in radio astronomy. The aim of the modelling process was to determine the deviation of the surface away from its true parabolic shape, in order to estimate the surface efficiency with respect to its principal receiving frequency. The main mathematical problems were the optimal and unbiased estimation the orientation of the dish and the fitting of a parabola to the local orientation or coordinate system, which were done by both orthogonal and algebraic minimization using the least-squares method. Due to the mesh structure of the dish, a classification method was also applied to filter out erroneous points being influenced by the supporting structure behind the dish. Finally, a comparison is performed between the ideal parabolic shape, and the data collected from three different temporal intervals.

  3. Parabolic scaling beams.

    Science.gov (United States)

    Gao, Nan; Xie, Changqing

    2014-06-15

    We generalize the concept of diffraction free beams to parabolic scaling beams (PSBs), whose normalized intensity scales parabolically during propagation. These beams are nondiffracting in the circular parabolic coordinate systems, and all the diffraction free beams of Durnin's type have counterparts as PSBs. Parabolic scaling Bessel beams with Gaussian apodization are investigated in detail, their nonparaxial extrapolations are derived, and experimental results agree well with theoretical predictions.

  4. Parabolic trough systems; Parabolrinnensysteme

    Energy Technology Data Exchange (ETDEWEB)

    Geyer, M. [Flabeg Solar International GmbH (Germany); Lerchenmueller, H.; Wittwer, V. [Fraunhofer ISE, Freiburg (Germany); Haeberle, A. [PSE GmbH (Germany); Luepfert, E.; Hennecke, K. [DLR, Koeln (Germany); Schiel, W. [SBP (Germany); Brakmann, G. [Fichtner Solar GmbH (Germany)

    2002-07-01

    The technology of parabolic trough power plants is presented: History, comparative assessment of different types of parabolic trough collectors, fresnel collectors, solar tracking systems, thermal efficiency, further research, performance of the SEGS parabolic trough power station in California. [German] Die Technik von Parabolrinnen-Kraftwerken wird vorgestellt: Entwicklungsgeschichte, Vergleich verschiedener Parabolrinnenkollektoren, fresnel kollektoren, Nachfuehrsysteme, thermischer Wirkungsgrad, weiterer Forschungsbedarf und Betriebserfahrung mit dem SEGS Parabolrinnenkraftwerk in Kalifornien. (uke)

  5. Dish Stirling solar receiver program

    Science.gov (United States)

    Haglund, R. A.

    1980-01-01

    A technology demonstration of a Dish Stirling solar thermal electric system can be accomplished earlier and at a much lower cost than previous planning had indicated by employing technical solutions that allow already existing hardware, with minimum modifications, to be integrated into a total system with a minimum of development. The DSSR operates with a modified United Stirling p-40 engine/alternator and the JPL Test Bed Concentrator as a completely integrated solar thermal electric system having a design output of 25 kWe. The system is augmented by fossil fuel combustion which ensures a continuous electrical output under all environmental conditions. Technical and economic studies by government and industry in the United States and abroad identify the Dish Stirling solar electric system as the most appropriate, efficient and economical method for conversion of solar energy to electricity in applications when the electrical demand is 10 MWe and less.

  6. Design, Analysis and Optimization of a Solar Dish/Stirling System

    Directory of Open Access Journals (Sweden)

    Seyyed Danial Nazemi

    2016-02-01

    Full Text Available In this paper, a mathematical model by which the thermal and physical behavior of a solar dish/Stirling system was investigated, then the system was designed, analysed and optimized. In this regard, all of heat losses in a dish/Stirling system were calculated, then, the output net-work of the Stirling engine was computed, and accordingly, the system efficiency was worked out. These heat losses include convection and conduction heat losses, radiation heat losses by emission in the cavity receiver, reflection heat losses of solar energy in the parabolic dish, internal and external conduction heat losses, energy dissipation by pressure drops, and energy losses by shuttle effect in displacer piston in the Stirling engine. All of these heat losses in the parabolic dish, cavity receiver and Stirling engine were calculated using mathematical modeling in MatlabTM software. For validation of the proposed model, a 10 kW solar dish/Stirling system was designed and the simulation results were compared with the Eurodish system data with a reasonable degree of agreement. This model is used to investigate the effect of geometric and thermodynamic parameters including the aperture diameter of the parabolic dish and the cavity receiver, and the pressure of the compression space of the Stirling engine, on the system performance. By using the PSO method, which is an intelligent optimization technique, the total design was optimized and the optimal values of decision-making parameters were determined. The optimization has been done in two scenarios. In the first scenario, the optimal value of each designed parameter has been changed when the other parameters are equal to the designed case study parameters. In the second scenario, all of parameters were assumed in their optimal values. By optimization of the modeled dish/Stirling system, the total efficiency of the system improved to 0.60% in the first scenario and it increased from 21.69% to 22.62% in the second

  7. Manufacturing parabolic mirrors

    CERN Multimedia

    CERN PhotoLab

    1975-01-01

    The photo shows the construction of a vertical centrifuge mounted on an air cushion, with a precision of 1/10000 during rotation, used for the manufacture of very high=precision parabolic mirrors. (See Annual Report 1974.)

  8. A review of test results on solar thermal power modules with dish-mounted Stirling and Brayton cycle engines

    Science.gov (United States)

    Jaffe, Leonard D.

    1988-01-01

    This paper presents results of development tests of various solar thermal parabolic dish modules and assemblies that used dish-mounted Brayton or Stirling cycle engines for production of electric power. These tests indicate that early modules achieve net efficiencies up to 29 percent in converting sunlight to electricity, as delivered to the grid. Various equipment deficiencies were observed and a number of malfunctions occurred. The performance measurements, as well as the malfunctions and other test experience, provided information that should be of value in developing systems with improved performance and reduced maintenance.

  9. Hangzhou People and Bamboo Shoots Dish

    Institute of Scientific and Technical Information of China (English)

    LINDA; LEE

    1995-01-01

    SOON we’ll celebrate the new year. According to Hangzhou tradition, every family will cook a hot dish for this feast which will include shredded winter bamboo shoots, hotbed chives, shredded meat and smoked bean curd. In addition, some families will also cook a dish of "braised

  10. Parabolic Strip Telescope

    CERN Document Server

    Chadzitaskos, Goce

    2013-01-01

    We present a proposal of a new type of telescopes using a rotating parabolic strip as the primary mirror. It is the most principal modification of the design of telescopes from the times of Galileo and Newton. In order to demonstrate the basic idea, the image of an artificial constellation observed by this kind of telescope was reconstructed using the techniques described in this article. As a working model of this new telescope, we have used an assembly of the primary mirror---a strip of acrylic glass parabolic mirror 40 cm long and 10 cm wid shaped as a parabolic cylinder of focal length 1 m---and an artificial constellation, a set of 5 apertures in a distance of 5 m illuminated from behind. In order to reconstruct the image, we made a series of snaps, each after a rotation of the constellation by 15 degrees. Using Matlab we reconstructed the image of the artificial constellation.

  11. A Hybrid Power Generation System Combined Parabolic Trough Solar Collectors and Chemical Heat Pump%槽式太阳能集热与化学热泵耦合的复合发电系统

    Institute of Scientific and Technical Information of China (English)

    王艳娟; 刘启斌; 金红光

    2014-01-01

    A hybrid power generation system combined parabolic trough solar collectors and chemical heat pump is proposed in the paper.The thermodynamic performance of the proposed system and the effects of the key operating parameters on the performances of the system were investigated.The relationship between the direct normal irradiation (DNI) and the performance of the proposed system was disclosed.When the DNI was larger than the design condition,variation of the mass flow rate of CaO for solar energy storage with the DNI was analyzed.In the design conditions,the output work of the system is 335.7 MW the thermal efficiency of the proposed system is 30.4%,and the solar-to-electric efficiency of the proposed system can reach 23.6%.The hybrid power system proposed can improve the thermal efficiency significantly by increasing the steam parameters compared to the conventional solar parabolic trough power generating system.%本文提出了一种抛物槽式太阳能集热与化学热泵耦合的复合发电系统,对其热力性能进行了分析,并研究了反应器中反应蒸汽温度、镜场加热给水温度等关键运行参数对系统性能的影响.研究了太阳能特征参数对系统性能的影响规律,分析了太阳直射辐照强度(DNI)高于设计工况时,储能材料氧化钙的量与DNI的关系.设计工况下,系统输出功335.7 MW,热效率为30.4%,发电效率23.6%.所提出的系统,为解决槽式太阳能单独热发电系统蒸汽参数低导致动力循环热效率低的难题提供了新途径.

  12. Parabolic k-ample bundles

    CERN Document Server

    Biswas, Indranil

    2011-01-01

    We construct projectivization of a parabolic vector bundle and a tautological line bundle over it. It is shown that a parabolic vector bundle is ample if and only if the tautological line bundle is ample. This allows us to generalize the notion of a k-ample bundle, introduced by Sommese, to the context of parabolic bundles. A parabolic vector bundle $E_*$ is defined to be k-ample if the tautological line bundle ${\\mathcal O}_{{\\mathbb P}(E_*)}(1)$ is $k$--ample. We establish some properties of parabolic k-ample bundles.

  13. The Translation of Chinese Dish Names

    Institute of Scientific and Technical Information of China (English)

    龚佳文

    2015-01-01

    The traditional food of a nation reflects its historical and cultural characteristics This thesis begins with an introduction to the translation situation of Chinese dish names and its existing problem nowadays, and proceeds to the translation principles and tactics for English translation of the names of Chinese dishes, based on Eugene A. Nida’ s Functional Equivalence, with an aim to improve translation efficiency and promote cross-cultural communication, and promoting Chinese food culture throughout the globe.

  14. Mechatronic Prototype of Parabolic Solar Tracker.

    Science.gov (United States)

    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.

  15. Mechatronic Prototype of Parabolic Solar Tracker

    Directory of Open Access Journals (Sweden)

    Carlos Morón

    2016-06-01

    Full Text Available 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.

  16. Session: Parabolic Troughs (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Parabolic Stein Manifolds

    CERN Document Server

    Aytuna, Aydin

    2011-01-01

    An open Riemann surface is called parabolic in case every bounded subharmonic function on it reduces to a constant. Several authors introduced seemingly different analogs of this notion for Stein manifolds of arbitrary dimension. In the first part of this note we compile these notions of parabolicity and give some immediate relations among them. In section 3 we relate some of these notions to the linear topological type of the Fr\\'echet space of analytic functions on the given manifold. In sections 4 and 5 we look at some examples and show, for example, that the complement of the zero set of a Weierstrass polynomial possesses a continuous plurisubharmonic exhaustion function that is maximal off a compact subset.

  18. Mahonians and parabolic quotients

    CERN Document Server

    Caselli, Fabrizio

    2011-01-01

    We study the distribution of the major index with sign on some parabolic quotients of the symmetric group, extending and generalizing simultaneously results of Panova [G. Panova, Bijective enumeration of permutations starting with a longest increasing subsequence, Discrete Math. Theor. Comput. Sci. Proc. AN (2010), 841--850], Gessel-Simion [M. Wachs, An involution for signed Eulerian numbers, Discrete Math. 99 (1992), 59--62] and Adin-Gessel-Roichman [R. Adin, I. Gessel and Y. Roichman, Signed Mahonians, J. Combin. Theory Ser. A 109 (2005), 25--43]. We further consider and compute the distribution of the flag-major index on some parabolic quotients of wreath products and other related groups. All these distributions turn out to have very simple factorization formulas.

  19. Optimization of Dish Solar Collectors with and without Secondary Concentrators

    Science.gov (United States)

    Jaffe, L. D.

    1982-01-01

    Methods for optimizing parabolic dish solar collectors and the consequent effects of various optical, thermal, mechanical, and cost variables are examined. The most important performance optimization is adjusting the receiver aperture to maximize collector efficiency. Other parameters that can be adjusted to optimize efficiency include focal length, and, if a heat engine is used, the receiver temperature. The efficiency maxima associated with focal length and receiver temperature are relatively broad; it may, accordingly, be desirable to design somewhat away from the maxima. Performance optimization is sensitive to the slope and specularity errors of the concentrator. Other optical and thermal variables affecting optimization are the reflectance and blocking factor of the concentrator, the absorptance and losses of the receiver, and, if a heat engine is used, the shape of the engine efficiency versus temperature curve. Performance may sometimes be improved by use of an additional optical element (a secondary concentrator) or a receiver window if the errors of the primary concentrator are large or the receiver temperature is high.

  20. Courant Algebroids in Parabolic Geometry

    CERN Document Server

    Armstrong, Stuart

    2011-01-01

    To a smooth manifold $M$, a parabolic geometry associates a principal bundle, which has a parabolic subgroup of a semisimple Lie group as its structure group, and a Cartan connection. We show that the adjoint tractor bundle of a regular normal parabolic geometry can be endowed with the structure of a Courant algebroid. This gives a class of examples of transitive Courant algebroids that are not exact.

  1. Operational data and thermodynamic modeling of a Stirling-dish demonstration installation in desert conditions

    Science.gov (United States)

    Nilsson, Martin; Jamot, Jakob; Malm, Tommy

    2017-06-01

    To field test its Stirling-dish unit, Cleanergy AB of Sweden in Q1 2015 built a ten unit demo park in Dubai. The first STE (Solar Thermal Energy) generation of its Stirling genset, the C11S, had at its core an 11 kWel Stirling engine/generator combination. The genset was mated with a parabolic concentrator developed for the genset by a supplier. Local weather conditions in Dubai provide opportunities to test performance in an environment with high insolation and high ambient temperature. In addition, the conditions in Dubai are windy, salty, humid and dusty, historically challenging for solar technologies [1]. In Q1 2016 one of the C11S Stirling-dish units was replaced by the first prototype of Cleanergy's second generation Stirling genset, the Sunbox, and an in-house developed parabolic concentrator. Operational data from field testing during the spring of 2016 are presented and discussed and show the large performance improvement achieved with the Sunbox unit.

  2. Design, simulation and optimization of a solar dish collector with spiral-coil thermal absorber

    Directory of Open Access Journals (Sweden)

    Pavlović Saša R.

    2016-01-01

    Full Text Available The efficient conversion of solar radiation into heat at high temperature levels requires the use of concentrating solar collectors. The goal of this paper is to present the optical and the thermal analysis of a parabolic dish concentrator with a spiral coil receiver. The parabolic dish reflector consists of 11 curvilinear trapezoidal reflective petals constructed by PMMA with silvered mirror layer and has a diameter of 3.8 m, while its focal distance is 2.26m. This collector is designed with commercial software SolidWorks and simulated, optically and thermally in its Flow Simulation Studio. The optical analysis proved that the ideal position of the absorber is at 2.1m from the reflector in order to maximize the optical efficiency and to create a relative uniform heat flux over the absorber. In thermal part of the analysis, the energetic efficiency was calculated approximately 65%, while the exergetic efficiency is varied from 4% to 15% according to the water inlet temperature. Moreover, other important parameters as the heat flux and temperature distribution over the absorber are presented. The pressure drop of the absorber coil is calculated at 0.07bar, an acceptable value.

  3. Two new designs of parabolic solar collectors

    Directory of Open Access Journals (Sweden)

    Karimi Sadaghiyani Omid

    2014-01-01

    Full Text Available In this work, two new compound parabolic trough and dish solar collectors are presented with their working principles. First, the curves of mirrors are defined and the mathematical formulation as one analytical method is used to trace the sun rays and recognize the focus point. As a result of the ray tracing, the distribution of heat flux around the inner wall can be reached. Next, the heat fluxes are calculated versus several absorption coefficients. These heat flux distributions around absorber tube are functions of angle in polar coordinate system. Considering, the achieved heat flux distribution are used as a thermal boundary condition. After that, Finite Volume Methods (FVM are applied for simulation of absorber tube. The validation of solving method is done by comparing with Dudley's results at Sandia National Research Laboratory. Also, in order to have a good comparison between LS-2 and two new designed collectors, some of their parameters are considered equal with together. These parameters are consist of: the aperture area, the measures of tube geometry, the thermal properties of absorber tube, the working fluid, the solar radiation intensity and the mass flow rate of LS-2 collector are applied for simulation of the new presented collectors. After the validation of the used numerical models, this method is applied to simulation of the new designed models. Finally, the outlet results of new designed collector are compared with LS-2 classic collector. Obviously, the obtained results from the comparison show the improving of the new designed parabolic collectors efficiency. In the best case-study, the improving of efficiency are about 10% and 20% for linear and convoluted models respectively.

  4. Dish-mounted latent heat buffer storage

    Science.gov (United States)

    Manvi, R.

    1981-01-01

    Dish-mounted latent heat storage subsystems for Rankine, Brayton, and Stirling engines operating at 427 C, 816 C, and 816 C respectively are discussed. Storage requirements definition, conceptual design, media stability and compatibility tests, and thermal performance analyses are considered.

  5. Effects of pointing errors on receiver performance for parabolic dish solar concentrators

    Science.gov (United States)

    Hughes, R. O.

    1978-01-01

    The effects of dynamic (moving) pointing errors on the performance of solar thermal receivers is investigated. Only point focusing types of solar collectors are considered. The key element in the study is the analytical derivation of the intercept factor that relates pointing errors to captured energy at the receiver. A detailed example using typical parameter values is modeled on the digital computer and demonstrates the theory and the dynamic nature of the problem.

  6. Commercialization of dish-Stirling solar terrestrial systems

    Science.gov (United States)

    Ross, Brad; Penswick, Barry; White, Maury; Cooper, Martin; Farbman, Gerald

    1990-01-01

    The requirements for dish-Stirling commercialization are described. The requirements for practical terrestrial power systems, both technical and economic, are described. Solar energy availability, with seasonal and regional variations, is discussed. The advantages and disadvantages of hybrid operation are listed. The two systems described use either a 25-kW free-piston Stirling hydraulic engine or a 5-kW kinematic Stirling engine. Both engines feature long-life characteristics that result from the use of welded metal bellows as hermetic seals between the working gas and the crankcase fluid. The advantages of the systems, the state of the technology, and the challenges that remain are discussed. Technology transfer between solar terrestrial Stirling applications and other Stirling applications is predicted to be important and synergistic.

  7. Commercialization of dish-Stirling solar terrestrial systems

    Science.gov (United States)

    Ross, Brad; Penswick, Barry; White, Maury; Cooper, Martin; Farbman, Gerald

    1990-01-01

    The requirements for dish-Stirling commercialization are described. The requirements for practical terrestrial power systems, both technical and economic, are described. Solar energy availability, with seasonal and regional variations, is discussed. The advantages and disadvantages of hybrid operation are listed. The two systems described use either a 25-kW free-piston Stirling hydraulic engine or a 5-kW kinematic Stirling engine. Both engines feature long-life characteristics that result from the use of welded metal bellows as hermetic seals between the working gas and the crankcase fluid. The advantages of the systems, the state of the technology, and the challenges that remain are discussed. Technology transfer between solar terrestrial Stirling applications and other Stirling applications is predicted to be important and synergistic.

  8. Modeling the small-scale dish-mounted solar thermal Brayton cycle

    Science.gov (United States)

    Le Roux, Willem G.; Meyer, Josua P.

    2016-05-01

    The small-scale dish-mounted solar thermal Brayton cycle (STBC) makes use of a sun-tracking dish reflector, solar receiver, recuperator and micro-turbine to generate power in the range of 1-20 kW. The modeling of such a system, using a turbocharger as micro-turbine, is required so that optimisation and further development of an experimental setup can be done. As a validation, an analytical model of the small-scale STBC in Matlab, where the net power output is determined from an exergy analysis, is compared with Flownex, an integrated systems CFD code. A 4.8 m diameter parabolic dish with open-cavity tubular receiver and plate-type counterflow recuperator is considered, based on previous work. A dish optical error of 10 mrad, a tracking error of 1° and a receiver aperture area of 0.25 m × 0.25 m are considered. Since the recuperator operates at a very high average temperature, the recuperator is modeled using an updated ɛ-NTU method which takes heat loss to the environment into consideration. Compressor and turbine maps from standard off-the-shelf Garrett turbochargers are used. The results show that for the calculation of the steady-state temperatures and pressures, there is good comparison between the Matlab and Flownex results (within 8%) except for the recuperator outlet temperature, which is due to the use of different ɛ-NTU methods. With the use of Matlab and Flownex, it is shown that the small-scale open STBC with an existing off-the-shelf turbocharger could generate a positive net power output with solar-to-mechanical efficiency of up to 12%, with much room for improvement.

  9. The Existing Problems in the Translation of Chinese Dish Names

    Institute of Scientific and Technical Information of China (English)

    易高燕

    2009-01-01

    China has a long rich history of dietary culture, and with the increasing communication with other countries and cultures, it is of great significance to translate the Chinese dish names and food with accuracy and efficiency. In this easy, the writer discusses some existing problems in the translation of Chinese dish names, and put forward several useful methods in translating Chinese dish names.

  10. Invariant foliations for parabolic equations

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    It is proved for parabolic equations that under certain conditions the weak (un-)stable manifolds possess invariant foliations, called strongly (un-)stable foliations. The relevant results on center manifolds are generalized to weak hyperbolic manifolds.

  11. Parabolic sheaves on logarithmic schemes

    OpenAIRE

    Borne, Niels; Vistoli, Angelo

    2010-01-01

    We show how the natural context for the definition of parabolic sheaves on a scheme is that of logarithmic geometry. The key point is a reformulation of the concept of logarithmic structure in the language of symmetric monoidal categories, which might be of independent interest. Our main result states that parabolic sheaves can be interpreted as quasi-coherent sheaves on certain stacks of roots.

  12. Parabolic metamaterials and Dirac bridges

    Science.gov (United States)

    Colquitt, D. J.; Movchan, N. V.; Movchan, A. B.

    2016-10-01

    A new class of multi-scale structures, referred to as `parabolic metamaterials' is introduced and studied in this paper. For an elastic two-dimensional triangular lattice, we identify dynamic regimes, which corresponds to so-called `Dirac Bridges' on the dispersion surfaces. Such regimes lead to a highly localised and focussed unidirectional beam when the lattice is excited. We also show that the flexural rigidities of elastic ligaments are essential in establishing the `parabolic metamaterial' regimes.

  13. A compendium of solar dish/Stirling technology

    Energy Technology Data Exchange (ETDEWEB)

    Stine, W.B. [California State Polytechnic Univ., Pomona, CA (United States). Dept. of Mechanical Engineering; Diver, R.B. [Sandia National Labs., Albuquerque, NM (United States)

    1994-01-01

    This report surveys the emerging dish/Stirling technology. It documents -- using consistent terminology the design characteristics of dish concentrators, receivers, and Stirling engines applicable to solar electric power generation. Development status and operating experience for each system and an overview of dish/Stirling technology are also presented. This report enables comparisons of concentrator, receiver, and engine technologies. Specifications and performance data are presented on systems and on components that are in use or that could be used in dish/Stirling systems. This report is organized into two parts: The first part (Chapters 1 through 4) provides an overview of dish/Stirling technology -- the dish/ Stirling components (concentrator, receiver, and engine/alternator), current technology, basic theory, and technology development. The second part (Chapters 5 through 7) provides a detailed survey of the existing dish/Stirling concentrators, receivers, and engine/alternators.

  14. Parabolic aircraft solidification experiments

    Science.gov (United States)

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

    1996-01-01

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

  15. Optical Design of a Solar Dish Concentrator Based on Triangular Membrane Facets

    Directory of Open Access Journals (Sweden)

    Hongcai Ma

    2012-01-01

    Full Text Available The design of a solar dish concentrator is proposed based on triangular membrane facets for space power applications. The facet concentrator approximates a parabolic surface supported by a deployable perimeter truss structure, which originates from a large aperture space antenna. For optimizing the number of facets rows and focal-diameter ratio of the concentrator, Monte Carlo ray-tracing method is utilized to determine optical performance of the concentrator, and the system root-mean-square (RMS deviation is considered in this design procedure. A 600-facet concentrator with focal-diameter ratio of 1.1 will achieve 83.63% of radiative collection efficiency over a 15 cm radius disk located in the focal plane, with a mean solar concentration ratio exceeding 300. The study in this paper is helpful for the development of the membrane facet concentrator.

  16. Engineering parabolic beams with dynamic intensity profiles.

    Science.gov (United States)

    Ruelas, Adrian; Lopez-Aguayo, Servando; Gutiérrez-Vega, Julio C

    2013-08-01

    We present optical fields formed by superposing nondiffracting parabolic beams with distinct longitudinal wave-vector components, generating light profiles that display intensity fluxes following parabolic paths in the transverse plane. Their propagation dynamics vary depending on the physical mechanism originating interference, where the possibilities include constructive and destructive interference between traveling parabolic beams, interference between stationary parabolic modes, and combinations of these. The dark parabolic region exhibited by parabolic beams permits a straightforward superposition of intensity fluxes, allowing formation of a variety of profiles, which can exhibit circular, elliptic, and other symmetries.

  17. An Automatic High Efficient Method for Dish Concentrator Alignment

    OpenAIRE

    Yong Wang; Song Li; Jinshan Xu; Yijiang Wang; Xu Cheng; Changgui Gu; Shengyong Chen; Bin Wan

    2014-01-01

    Alignment of dish concentrator is a key factor to the performance of solar energy system. We propose a new method for the alignment of faceted solar dish concentrator. The isosceles triangle configuration of facet’s footholds determines a fixed relation between light spot displacements and foothold movements, which allows an automatic determination of the amount of adjustments. Tests on a 25 kW Stirling Energy System dish concentrator verify the feasibility, accuracy, and efficiency of our...

  18. Facet development for a faceted stretched-membrane dish by Solar Kinetics, Inc

    Energy Technology Data Exchange (ETDEWEB)

    Schertz, P.T.; Brown, D.C.; Konnerth, A. III (Solar Kinetics, Inc., Dallas, TX (United States))

    1991-07-01

    A 3.6-meter diameter stretched-membrane optical facet for a parabolic dish has been successfully designed and demonstrated under contract with Sandia National Laboratories. Twelve facets identical to them will be used to make the lightweight reflector of the dish. The project goal of 2.5-mrad surface accuracy was met with each of the two full-sized prototypes, and accuracies of as low as 1.1 mrad were achieved. The facet weight is 11.7 kg/m{sup 2} (2.4lbs/ft{sup 2}). The facet is similar in construction to the successful stretched-membrane heliostat; it has two thin metal membranes attached to a ring. However, the front membrane for this facet is plastically formed at the factor in order to achieve a shorter facet f/D (approximately 3.0). A passive tether restrains the from membrane when not in operation, that is, when the stabilizing vacuum is off. The optical surface is achieved with a silvered-acrylic film laminated to the metal membrane. The facet is expected to cost $55.40/m{sup 2} at a production rate of 10,000 facets per year and $115, 000/m{sup 2}-at a production rate of 500 facets a year. Several key issues have been resolved. Stress concentrations due to seams in the reflective laminate did not cause membrane rupture during forming as they have for dishes with lower focal length-to-diameter ratios. The laminate survived the forming process and simulated operation without deterioration. The optical effect of the tether on the membrane was tested and found to be very small. Most important, highly accurate shapes were obtained using a simple forming procedure. Additional tests are needed to demonstrate process repeatablility and facet performance in typical operating conditions. 18 refs., 36 figs., 11 tabs.

  19. Facet development for a faceted stretched-membrane dish by Solar Kinetics, Inc.

    Science.gov (United States)

    Schertz, P. T.; Brown, D. C.; Konnerth, A., III

    1991-07-01

    A 3.6-meter diameter stretched-membrane optical facet for a parabolic dish has been successfully designed and demonstrated under contract with Sandia National Laboratories. Twelve facets identical to them will be used to make the lightweight reflector of the dish. The project goal of 2.5-mrad surface accuracy was met with each of the two full-sized prototypes, and accuracies of as low as 1.1 mrad were achieved. The facet weight is 11.7 kg/sq m (2.4 lbs/sq ft). The facet is similar in construction to the successful stretched-membrane heliostat; it has two thin metal membranes attached to a ring. However, the front membrane for this facet is plastically formed at the factor in order to achieve a shorter facet f/D (approximately 3.0). A passive tether restrains the front membrane when not in operation, that is, when the stabilizing vacuum is off. The optical surface is achieved with a silvered-acrylic film laminated to the metal membrane. The facet is expected to cost $55.40/sq m at a production rate of 10,000 facets per year and $115,000/sq m at a production rate of 500 facets a year. Several key issues have been resolved. Stress concentrations due to seams in the reflective laminate did not cause membrane rupture during forming as they have for dishes with lower focal length-to-diameter ratios. The laminate survived the forming process and simulated operation without deterioration. The optical effect of the tether on the membrane was tested and found to be very small. Most important, highly accurate shapes were obtained using a simple forming procedure. Additional tests are needed to demonstrate process repeatability and facet performance in typical operating conditions.

  20. OPTIMAL CONTROL PROBLEM FOR PARABOLIC VARIATIONAL INEQUALITIES

    Institute of Scientific and Technical Information of China (English)

    汪更生

    2001-01-01

    This paper deals with the optimal control problems of systems governed by a parabolic variational inequality coupled with a semilinear parabolic differential equations.The maximum principle and some kind of approximate controllability are studied.

  1. On purpose simulation model for molten salt CSP parabolic trough

    Science.gov (United States)

    Caranese, Carlo; Matino, Francesca; Maccari, Augusto

    2017-06-01

    The utilization of computer codes and simulation software is one of the fundamental aspects for the development of any kind of technology and, in particular, in CSP sector for researchers, energy institutions, EPC and others stakeholders. In that extent, several models for the simulation of CSP plant have been developed with different main objectives (dynamic simulation, productivity analysis, techno economic optimization, etc.), each of which has shown its own validity and suitability. Some of those models have been designed to study several plant configurations taking into account different CSP plant technologies (Parabolic trough, Linear Fresnel, Solar Tower or Dish) and different settings for the heat transfer fluid, the thermal storage systems and for the overall plant operating logic. Due to a lack of direct experience of Molten Salt Parabolic Trough (MSPT) commercial plant operation, most of the simulation tools do not foresee a suitable management of the thermal energy storage logic and of the solar field freeze protection system, but follow standard schemes. ASSALT, Ase Software for SALT csp plants, has been developed to improve MSPT plant's simulations, by exploiting the most correct operational strategies in order to provide more accurate technical and economical results. In particular, ASSALT applies MSPT specific control logics for the electric energy production and delivery strategy as well as the operation modes of the Solar Field in off-normal sunshine condition. With this approach, the estimated plant efficiency is increased and the electricity consumptions required for the plant operation and management is drastically reduced. Here we present a first comparative study on a real case 55 MWe Molten Salt Parabolic Trough CSP plant placed in the Tibetan highlands, using ASSALT and SAM (System Advisor Model), which is a commercially available simulation tool.

  2. Parabolic troughs to increase the geothermal wells flow enthalpy

    Energy Technology Data Exchange (ETDEWEB)

    Lentz, Alvaro; Almanza, Rafael [Engineering Institute, National Autonomous University of Mexico, Building 12, Cuidad Universitaria, Mexico D.F., A.P. 70-472, C.P. 04510 (Mexico)

    2006-10-15

    This work investigates the feasibility of using parabolic trough solar field to increase the enthalpy from geothermal wells' flow in order to increase the steam tons; in addition, it is possible to prevent silica deposition in the geothermal process. The high levels of irradiance in Northwestern Mexico make it possible to integrate a solar-geothermal hybrid system that uses two energy resources to provide steam for the geothermal cycle, like the Cerro Prieto geothermal field. The plant consists of a geothermal well, a parabolic trough solar field in series, flash separator, steam turbine and condenser. Well '408' of Cerro Prieto IV has enthalpy of 1566kJ/kg and its quality must be increased by 10 points, which requires a {delta}h of 194.4kJ/kg. Under these considerations the parabolic troughs area required will be 9250m{sup 2}, with a flow of 92.4tons per hour (25.67kg/s). The solar field orientation is a N-S parabolic trough concentrator. The silica content in the Cerro Prieto geothermal brine causes problems for scaling at the power facility, so scale controls must be considered. (author)

  3. OPTICAL MODEL AND NUMERICAL SIMULATION OF THE NEW OFFSET TYPE PARABOLIC CONCENTRATOR WITH TWO TYPES OF SOLAR RECEIVERS

    Directory of Open Access Journals (Sweden)

    Saša Pavlović

    2015-08-01

    Full Text Available The paper presents a physical and mathematical model of the new offset type parabolic concentrator and a numerical procedure for predicting its optical performances. Also presented is the process of design and optical ray tracing analysis of a low cost solar concentrator for medium temperature applications. This study develops and applies a new mathematical model for estimating the intercept factor of the solar concentrator based on its geometrical and optical behavior. The solar concentrating system consists of three offset parabolic dish reflectors and a solar thermal absorber at the focus. Two types of absorbers are discussed. One is a flat plate circular absorber and the other a spiral smooth pipe absorber. The simulation results could serve as a useful reference for design and optimization of offset parabolic concentrators.

  4. Self-similar parabolic plasmonic beams.

    Science.gov (United States)

    Davoyan, Arthur R; Turitsyn, Sergei K; Kivshar, Yuri S

    2013-02-15

    We demonstrate that an interplay between diffraction and defocusing nonlinearity can support stable self-similar plasmonic waves with a parabolic profile. Simplicity of a parabolic shape combined with the corresponding parabolic spatial phase distribution creates opportunities for controllable manipulation of plasmons through a combined action of diffraction and nonlinearity.

  5. Plane and parabolic solar panels

    CERN Document Server

    Sales, J H O

    2009-01-01

    We present a plane and parabolic collector that absorbs radiant energy and transforms it in heat. Therefore we have a panel to heat water. We study how to increment this capture of solar beams onto the panel in order to increase its efficiency in heating water.

  6. Parabolic tapers for overmoded waveguides

    Science.gov (United States)

    Doane, J.L.

    1983-11-25

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

  7. Low Power Thermodynamic Solar Energy Conversion: Coupling of a Parabolic Trough Concentrator and an Ericsson Engine

    Directory of Open Access Journals (Sweden)

    Pascal Stouffs

    2007-03-01

    Full Text Available This paper considers thermodynamic conversion of solar energy into electric energy (up to maximum 50 kWe, presenting a very brief review of the possible systems: the ‘Dish/Stirling’ technology, which relies on high temperature Stirling engines and requires high solar energy; low temperature differential thermal engine using direct solar energy without any concentration but with very low power per unit volume or unit mass of the system; and the intermediate solar energy concentration ratio.A theoretical investigation on the coupling of a two-stage parabolic trough concentrator with a reciprocating Joule cycle air engine (i.e. an Ericsson hot air engine in open cycle is presented. It is shown that there is an optimal operating point that maximises the mechanical power produced by the thermal engine. The interest of coupling a simple, low cost parabolic trough and a simple, low technology, mid-DT Ericsson engine is confirmed.

  8. Dish/Stirling for Department of Defense applications final report

    Energy Technology Data Exchange (ETDEWEB)

    Diver, R.B.; Menicucci, D.F. [Sandia National Labs., Albuquerque, NM (United States). Energy and Environment Div.

    1997-03-01

    This report describes a Strategic Environmental Research and Development Program (SERDP) project to field a dish/Stirling system at a southwestern US military facility. This project entitled ``Dish/Stirling for DoD Applications`` was started in August 1993 and was completed in September 1996. The project`s objective was to assist military facilities to field and evaluate emerging environmentally sound and potentially economical dish/Stirling technology. Dish/Stirling technology has the potential to produce electricity at competitive costs while at the same time providing a secure and environmentally benign source of power. In accordance with the SERDP charter, this project leveraged a US Department of Energy (DOE) cost-shared project between Sandia National Laboratories and Cummins Power Generation, Inc. (CPG). CPG is a wholly owned subsidiary of Cummins Engine Company, a leading manufacturer of diesel engines. To accomplish this objective, the project called for the installation of a dish/Stirling system at a military facility to establish first-hand experience in the operation of a dish/Stirling system. To scope the potential DoD market for dish/Stirling technology and to identify the site for the demonstration, a survey of southwestern US military facilities was also conducted. This report describes the project history, the Cummins dish/Stirling system, results from the military market survey, and the field test results.

  9. An Automatic High Efficient Method for Dish Concentrator Alignment

    Directory of Open Access Journals (Sweden)

    Yong Wang

    2014-01-01

    for the alignment of faceted solar dish concentrator. The isosceles triangle configuration of facet’s footholds determines a fixed relation between light spot displacements and foothold movements, which allows an automatic determination of the amount of adjustments. Tests on a 25 kW Stirling Energy System dish concentrator verify the feasibility, accuracy, and efficiency of our method.

  10. Dish-based CPV-T for rooftop generation

    Science.gov (United States)

    Davila-Peralta, Christian; Hyatt, Justin; Alfred, Dan; Struble, Morgan; Sodari, Frank; Angel, Roger

    2017-09-01

    Hybrid CPV-T with combined electrical and thermal output is well suited to solar generation from fixed limited areas, such as on the roof of an industrial or commercial facility with need for heat. This application will become especially attractive once overall electrical conversion efficiency of 40% is reached, as is projected for REhnu CPV systems using multijunction cells of 50% efficiency, anticipated in a few years. We outline here a configuration of dish- based CPV trackers optimized for close packing on a flat roof in a triangular grid, with a mirror area-to-ground area ratio of 50%. When the geometry of shadowing averaged over a year is taken into account, 80% of all the sunlight that would strike the rooftop is directed into the receivers. Such an array on a given area of flat roof will generate more electrical energy than would be possible with conventional PV panels, even if covering the entire rooftop, because of silicon's relative inefficiency. For example, in Tucson, the annual average global flux of 5.7 kWh/m2/day on a horizontal surface covered with 22% silicon modules will yield 1.25 kWh/m2/day. We show that a CPV system collecting 80% of all the direct sunlight of 7.0 kWh/m2 and converting it with 40% efficiency will yield 2.24 kWh/m2/day of rooftop area, nearly twice as much4. Thermal power will double again the total energy yield. A dual axis CPV-T tracker designed specifically very close spacing has been built to carry a single dish mirror of the standard type used in REhnu's M-8 generator, described by Stalcup et al in these proceedings1,2. Sunlight is collected and focused by a single square paraboloidal mirror, 1.65 × 1.65 m with focal length of 1.5 m. For closest possible packing without mechanical interference, and for broad distribution of load on a rooftop, the mirror and receiver are mounted to a C-ring structure, configured such that the elevation and azimuth axes intersect at a virtual pivot, at the center of the sphere that just

  11. El ídish en el teatro argentino

    Directory of Open Access Journals (Sweden)

    David William Foster

    2009-10-01

    Full Text Available Analise de tres instancias de teatro en ídish en Buenos Aires. La primera, un teatro hablado en ídish que surge de los contextos de la inmigración, que tiene que ver con la vida milenaria de los judíos, de los recuerdos del shetl, de los pogroms. La segunda es el teatro de las vivencias en territorio argentino, en el ámbito de la narrativa, ya en ídish, ya en castellano. La tercera ejemplifica el comienzo de la desaparición del ídish, con espectadores de otras ascendencias inmigratorias, que no van a entender el ídish, con la creciente debilidad del ídish en la colectividad, o por efecto de la asimilación o por el trágico hecho de que el ídish había emprendido la enorme decadencia impuestas por el nazismo, que desembocará eventualmente en la muerte del idioma que, en la Argentina y en muchos otros lugares, más se identificaba con los judíos.

  12. Dish stirling solar receiver combustor test program

    Science.gov (United States)

    Bankston, C. P.; Back, L. H.

    1981-01-01

    The operational and energy transfer characteristics of the Dish Stirling Solar Receiver (DSSR) combustor/heat exchanger system was evaluated. The DSSR is designed to operate with fossil fuel augmentation utilizing a swirl combustor and cross flow heat exchanger consisting of a single row of 4 closely spaced tubes that are curved into a conical shape. The performance of the combustor/heat exchanger system without a Stirling engine was studied over a range of operating conditions and output levels using water as the working fluid. Results show that the combustor may be started under cold conditions, controlled safety, and operated at a constant air/fuel ratio (10 percent excess air) over the required range of firing rates. Furthermore, nondimensional heat transfer coefficients based on total heat transfer are plotted versus Reynolds number and compared with literature data taken for single rows of closely spaced tubes perpendicular to cross flow. The data show enhanced heat transfer for the present geometry and test conditions. Analysis of the results shows that the present system meets specified thermal requirements, thus verifying the feasibility of the DSSR combustor design for final prototype fabrication.

  13. Prototype dish testing and analysis at Sandia National Laboratories

    Science.gov (United States)

    Grossman, J. W.; Houser, R. M.; Erdman, W. W.

    1991-12-01

    During the past year, Sandia National Laboratories performed on-sun testing of several dish concentrator concepts. These tests were undertaken at the National Solar Thermal Test Facility (NSTTF). Two of the tests were performed in support of the DOE Concentrator Receiver Development Program. The first was on-sun testing of the single-element stretched-membrane dish; this 7-meter diameter dish uses a single preformed metal membrane with an aluminized polyester optical surface and shows potential for future dish-Stirling systems. The next involved two prototype facets from the Faceted Stretched-Membrane Dish Program. These facets, representing competitive design concepts, are closest to commercialization. Five 1-meter triangular facets were tested on-sun as part of the development program for a solar dynamic system on Space Station Freedom. While unique in character, all the tests utilized the Beam Characterization System (BCS) as the main measurement tool and all were analyzed using the Sandia-developed CIRCE2 computer code. The BCS is used to capture and digitize an image of the reflected concentrator beam that is incident on a target surface. The CIRCE2 program provides a computational tool, which when given the geometry of the concentrator and target as well as other design parameters will predict the flux distribution of the reflected beam. One of these parameters, slope error, is the variable that has a major effect in determining the quality of the reflected beam. The methodology used to combine these two tools to predict uniform slope errors for the dishes is discussed in this document. As the Concentrator Development Programs continue, Sandia will test and evaluate two prototype dish systems. The first, the faceted stretched-membrane dish, is expected to be tested in 1992, followed by the full-scale single-element stretched-membrane dish in 1993. These tests will use the tools and methodology discussed in this document.

  14. Parabolic trough Project in Cerro Prieto, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lentz, A.; Cadenas, R.; Almanza, R.; Martinez, I.; Ruiz, V.

    2006-07-01

    Federal Electricity Commission (CFE), the most important electricity Company in Mexico wants to install a parabolic trough row in the Cerro Prieto Geothermal field. Cerro Prieto (CP) is the most important geothermal field in Mexico; this area has the highest levels of irradiance in the country. The levels of irradiance make it feasible to set up a solar collector field in the geothermal field to build a hybrid system in order to increase the steam and electricity production. There are several alternative in the hybrid system, depending where the solar field place is located. Two new options are presented in this paper. The first one uses water from the condenser in DSG with the solar field and steam is separated in the first separator. The second option (DSG), the steam produced is separated in an expansion vessel; the water is reinjected in the solar field and the steam goes to the turbine. This project plans to install an experimental facility to research and learning about the technology, CFE main objective will be the electricity generation; using steam from solar collectors using the existing turbines in CPIV; the second objective is to instruct the workers in the operation of the real facility. The third objective is to study the geothermal flow in the absorbers in Direct Steam Generation (DSG), which has salt and silica dissolved, and look for a possible solution for steam generation. The geothermal facilities have considerable experience using the brine flow, so it is not considered an impediment in the solar-geothermal hybrid system. (Author)

  15. Analysis and Design of a Dish/Stirling System for Solar Electric Generation with a 2.7 kW Air-Cooled Engine

    OpenAIRE

    Beltrán-Chacón R.; Velázquez-Limón N.; Sauceda-Carvajal D.

    2012-01-01

    This paper presents a mathematical modeling, simulation and design of a solar power system of a parabolic dish with an air-cooled Stirling engine of 2.7 kW. The model used for the solar concentrator, the cavity and the Stirling engine were successfully validated against experimental data. Based on a parametric study, the design of the components of the engine is carried out. The study shows that as system capacity increases, the overall efficiency is limited by the power required by the fan, ...

  16. Performance of the Southern California Edison Company Stirling dish

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, C.W. [Southern California Edison Co., Rosemead, CA (United States); Stone, K.W. [Mako Enterprises, Huntington Beach, CA (United States)

    1993-10-01

    McDonnell Douglas Astronautics Company (MDAC) and United Stirling AB of Sweden (USAB) formed a joint venture in 1982 to develop and produce a Stirling dish solar generating system. In this report, the six year development and testing program continued by the Southern California Edison Company (SCE) is described. Each Stirling dish module consists of a sun tracking dish concentrator developed by the MDAC and a Stirling engine driven power conversion unit (PCU) developed by USAB. The Stirling dish system demonstrated twice the peak and daily solar-to-electric conversion efficiency of any other system then under development. This system continues to set the performance standard for solar to electric systems being developed in the early 1990`s. Test data are presented and used to estimate the performance of a commercial system.

  17. Shanghai Dishes at the Beijing Asia Jinjiang Hotel

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    THE Beijing Asia Jinjiang Hotel in east Beijing is neither magnificent nor luxuriant, but the Shanghai cuisine served there makes it popular. The unforgettable dishes are the weapon that this hotel uses to compete with bigger hotels in the neighborhood.

  18. Modelling of Steam Generating Paraboloidal dish Solar Thermal Power System

    Energy Technology Data Exchange (ETDEWEB)

    Siangsukone, P.; Lovegrove, K.

    2006-07-01

    The Australian National University (ANU) has a 400m2 Paraboloidal dish solar concentrator system, informally named the Big Dish that produces superheated steam via a receiver mounted monotube boiler connected to 50kWe steam engine for electricity generation. This paper describes an investigation of the system and its components modelled using the TRNYSYS transient system simulation package. The system was modelled in the context of performance assessment for multiple dishes, central generation Rankine cycle power plants. Five new custom components; paraboloidal dish collector, steam cavity receiver, steam line or feedwater line, steam engine, and pressure drop calculator, were developed for the TRNSYS deck file constructed for this study. Validation tests were performed by comparing with the latest experimental results measured with a 1-minute time step and good agreement, with errors less than 10%, has been found. (Author)

  19. A special dish from traditional Turkish Cuisine: Stuffed lamb ribs

    Directory of Open Access Journals (Sweden)

    Emel Memis Kocaman

    2015-11-01

    Full Text Available Turkish people, who have a long historical background, have a rich culture in terms of cuisine. “Dolma” (meal made by stuffing/wrapping is one of the most important dishes of the Turkish Cuisine. Turks produced very different types of meals made by stuffing or wrapping and by combining herbals, meat and offals products. Stuffed Lamb Ribs (in Turkish; Kaburga Dolması or Sura is a special dish that is known in many regions of Turkey. Since it is a dish whose preparation is hard and requires virtuosity, it is generally cooked as a feast meal on religious holidays, and commonly cooked on the Feast of Sacrifice for Muslims. This study aims to present how “Stuffed Lamb Ribs” are prepared, which is one of the traditional dishes of Turkish Cuisine and is one stuffed dish that has started to become forgotten. In this study, the data was collected by personal interviews with source people who are over 60 years old, live in different provinces of Turkey, and traditionally cook this dish. This study ensures the promotion of a very special taste, which has begun to be forgotten and is not known widely even in Turkey, at an international level.

  20. Nonlinear elliptic-parabolic problems

    CERN Document Server

    Kim, Inwon C

    2012-01-01

    We introduce a notion of viscosity solutions for a general class of elliptic-parabolic phase transition problems. These include the Richards equation, which is a classical model in filtration theory. Existence and uniqueness results are proved via the comparison principle. In particular, we show existence and stability properties of maximal and minimal viscosity solutions for a general class of initial data. These results are new even in the linear case, where we also show that viscosity solutions coincide with the regular weak solutions introduced in [Alt&Luckhaus 1983].

  1. Experimental simulation of latent heat thermal energy storage and heat pipe thermal transport for dish concentrator solar receiver

    Science.gov (United States)

    Narayanan, R.; Zimmerman, W. F.; Poon, P. T. Y.

    1981-01-01

    Test results on a modular simulation of the thermal transport and heat storage characteristics of a heat pipe solar receiver (HPSR) with thermal energy storage (TES) are presented. The HPSR features a 15-25 kWe Stirling engine power conversion system at the focal point of a parabolic dish concentrator operating at 827 C. The system collects and retrieves solar heat with sodium pipes and stores the heat in NaF-MgF2 latent heat storage material. The trials were run with a single full scale heat pipe, three full scale TES containers, and an air-cooled heat extraction coil to replace the Stirling engine heat exchanger. Charging and discharging, constant temperature operation, mixed mode operation, thermal inertial, etc. were studied. The heat pipe performance was verified, as were the thermal energy storage and discharge rates and isothermal discharges.

  2. [Typical dishes consumed in Sonora: regionalization and nutrient contribution].

    Science.gov (United States)

    Jardines, R P; Bermúdez, M C; Wong, P; León, G

    1985-12-01

    This study deals with the development of a method to identify typical food dishes, successfully applied in the State of Sonora, Mexico. The State was divided into six regions considering the size of the territory and existence of different physical, economic and sociocultural conditions, and how they influence the consumption patterns. A list of 66 regional food dishes was prepared by interviewing housewives from different parts of Sonora who now lived in the city of Hermosillo. From this list, 47 dishes were identified as regionally consumed, and a State-wide survey was performed to determine their frequency of consumption. Based on the categories of "very frequently", "frequently" and "less frequently", a group of 15 dishes (2 per region, plus 3 dishes throughout the State) was selected. A questionnaire was used to obtain the different ways they had of preparing them. The "typical recipe" for each dish was also determined, using the mode as statistical parameter. Samples of these food dishes were prepared at the laboratory following the selected home recipes for proximal analysis and determination of their vitamin A, thiamine, riboflavin, niacin, calcium, phosphorus and iron content. The results showed that a portion of "gallina pinta" contributed more than 25% of the daily recommended intake established by the National Institute of Nutrition "Salvador Zubirán" (INNSZ) for an adult man for energy, protein, iron, niacin and 24.3% thiamine and 21.0% calcium. The "chivichangas de queso", for example, contributed 45.2% of the calcium requirement, and the "tamales de carne", 36% iron.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Absorber Tube with Internal Pin-Fins for Solar Parabolic Trough Collector

    Directory of Open Access Journals (Sweden)

    Kalidasan B.

    2016-01-01

    Full Text Available Solar parabolic trough collectors exploit solar energy for power generation in solar thermal power stations. These systems require long arrays of reflective troughs with absorber tube running along the axis of parabolic dish. A successful attempt to reduce the length of arrays was accomplished by experimentally analysing the modifications done in absorber tube. Two out of three tubes were fabricated and they were employed to obtain the performance parameters through experimentation conducted at VIT University, Vellore, India. Distilled water was used as the working fluid. Maximum efficiency of 39.12% was obtained at 451.6 W/m2 of direct normal irradiance (DNI for absorber tube with internal pin-fins and without glass tube (AFWGt compared to 8.15% obtained at same value of DNI and other conditions for simple absorber tube without glass cover (AWGt. Cylindrical parabolic trough available at the university was utilized, providing the basis for designing and fabrication of the tubes. Plots for varying mass flow rate at interval of 10 minutes were made against instantaneous thermal efficiency and heat utilized, for direct normal irradiance vs. temperature difference across the tubes and instantaneous thermal efficiency. Through the experimentation conducted, better performance was procured compared to earlier works. Thus, the proposal infers that absorber tube with internal fins has good scope for its application, both domestically as well as industrially. It also calls for further research and development of proposed techniques so as to achieve better performance curves.

  4. Solar tests of aperture plate materials for solar thermal dish collectors

    Science.gov (United States)

    Jaffe, L. D.

    1984-11-01

    If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the sun, motion of the concentrator may stop. As the sun moves relative to the earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fail apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.

  5. Performance and cost of energy transport and storage systems for dish applications using reversible chemical reactions

    Science.gov (United States)

    Schredder, J. M.; Fujita, T.

    1984-01-01

    The use of reversible chemical reactions for energy transport and storage for parabolic dish networks is considered. Performance and cost characteristics are estimated for systems using three reactions (sulfur-trioxide decomposition, steam reforming of methane, and carbon-dioxide reforming of methane). Systems are considered with and without storage, and in several energy-delivery configurations that give different profiles of energy delivered versus temperature. Cost estimates are derived assuming the use of metal components and of advanced ceramics. (The latter reduces the costs by three- to five-fold). The process that led to the selection of the three reactions is described, and the effects of varying temperatures, pressures, and heat exchanger sizes are addressed. A state-of-the-art survey was performed as part of this study. As a result of this survey, it appears that formidable technical risks exist for any attempt to implement the systems analyzed in this study, especially in the area of reactor design and performance. The behavior of all components and complete systems under thermal energy transients is very poorly understood. This study indicates that thermochemical storage systems that store reactants as liquids have efficiencies below 60%, which is in agreement with the findings of earlier investigators.

  6. Solar tests of aperture plate materials for solar thermal dish collectors

    Science.gov (United States)

    Jaffe, L. D.

    1984-01-01

    If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the sun, motion of the concentrator may stop. As the sun moves relative to the earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fail apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.

  7. Identifying Initial Condition in Degenerate Parabolic Equation with Singular Potential

    Directory of Open Access Journals (Sweden)

    K. Atifi

    2017-01-01

    Full Text Available A hybrid algorithm and regularization method are proposed, for the first time, to solve the one-dimensional degenerate inverse heat conduction problem to estimate the initial temperature distribution from point measurements. The evolution of the heat is given by a degenerate parabolic equation with singular potential. This problem can be formulated in a least-squares framework, an iterative procedure which minimizes the difference between the given measurements and the value at sensor locations of a reconstructed field. The mathematical model leads to a nonconvex minimization problem. To solve it, we prove the existence of at least one solution of problem and we propose two approaches: the first is based on a Tikhonov regularization, while the second approach is based on a hybrid genetic algorithm (married genetic with descent method type gradient. Some numerical experiments are given.

  8. Numerical Solution of Parabolic Equations

    DEFF Research Database (Denmark)

    Østerby, Ole

    These lecture notes are designed for a one-semester course on finite-difference methods for parabolic equations. These equations which traditionally are used for describing diffusion and heat-conduction problems in Geology, Physics, and Chemistry have recently found applications in Finance Theory....... Among the special features of this book can be mentioned the presentation of a practical approach to reliable estimates of the global error, including warning signals if the reliability is questionable. The technique is generally applicable for estimating the discretization error in numerical...... approximations which depend on a step size, such as numerical integration and solution of ordinary and partial differential equations. An integral part of the error estimation is the estimation of the order of the method and can thus satisfy the inquisitive mind: Is the order what we expect it to be from theopry...

  9. Technical status of the Dish/Stirling Joint Venture Program

    Science.gov (United States)

    Bean, John R.; Diver, Richard B.

    Initiated in 1991; the Dish/Stirling Joint Venture Program (DSJVP) is a 5-year, $17.2 million joint venture which is funded by Cummins Power Generation, Inc. (CPG) of Columbus, Indiana and the United States Department of Energy's (DOE) Solar Thermal and Biomass Power Division. Sandia National Laboratories administers and provides technical management for this contract on the DOE's behalf. In January, 1995; CPG advanced to Phase 3 of this three-phase contract. The objective of the DSJVP is to develop and commercialize a 7-kW. Dish/Stirling System for remote power markets by 1997. In this paper, the technical status of the major subsystems which comprise the CPG 7-kW(sub e) Dish/Stirling System is presented. These subsystems include the solar concentrator, heat pipe receiver, engine/alternator, power conditioning, and automatic controls.

  10. Experiments on the dish verification antenna china for the SKA

    Science.gov (United States)

    Chai, Xiaoming; Liu, Bin; Yu, Lei; Yu, Shenghua; Wu, Di; Liu, Lijia

    2016-12-01

    The Square Kilometre Array (SKA) is expected to become the world's most powerful radio telescope at meter and centimeter wavelength in the coming decades. The construction of SKA will be divided into two phases. The first phase (SKA1), scheduled for completion in 2023, will construct 10 % of the whole collecting area. The second phase (SKA2) will build the rest 90 % collecting area. The SKA1 consists of several types of arrays including SKA1-low and SKA1-mid. The latter is a dish array consisting of 200 medium-size antennas. The integrated dish array in SKA2 will expand to 2500 dishes, spreading 3000 kilometers across the southern part of Africa. The demanding specifications and enormous number of the SKA dish raise challenges in the dish development such as mass production with high performance at low cost, quick installation and high reliability. Dish Verification Antenna China (DVA-C) was built as one of three initial prototypes. A novel single-piece panel reflector made of carbon fiber reinforced polymer (CFRP) was adopted. In this study, an L-band receiver is installed to make DVA-C a complete system for experiments on antenna performance test and preliminary observations. The performance of DVA-C including the system noise temperature, pointing accuracy, antenna pattern, and aperture efficiency has been tested. Preliminary observations such as pulsars and HI are then conducted, which indicates that the DVA-C can not only serve as an educational instrument and key technology test bed, but also be applied for scientific work such as pulsar timing, all-sky HI survey, multi-frequency monitoring of variable sources etc.

  11. Experiments on the dish verification antenna china for the SKA

    Science.gov (United States)

    Chai, Xiaoming; Liu, Bin; Yu, Lei; Yu, Shenghua; Wu, Di; Liu, Lijia

    2016-09-01

    The Square Kilometre Array (SKA) is expected to become the world's most powerful radio telescope at meter and centimeter wavelength in the coming decades. The construction of SKA will be divided into two phases. The first phase (SKA1), scheduled for completion in 2023, will construct 10 % of the whole collecting area. The second phase (SKA2) will build the rest 90 % collecting area. The SKA1 consists of several types of arrays including SKA1-low and SKA1-mid. The latter is a dish array consisting of ~200 medium-size antennas. The integrated dish array in SKA2 will expand to 2500 dishes, spreading 3000 kilometers across the southern part of Africa. The demanding specifications and enormous number of the SKA dish raise challenges in the dish development such as mass production with high performance at low cost, quick installation and high reliability. Dish Verification Antenna China (DVA-C) was built as one of three initial prototypes. A novel single-piece panel reflector made of carbon fiber reinforced polymer (CFRP) was adopted. In this study, an L-band receiver is installed to make DVA-C a complete system for experiments on antenna performance test and preliminary observations. The performance of DVA-C including the system noise temperature, pointing accuracy, antenna pattern, and aperture efficiency has been tested. Preliminary observations such as pulsars and HI are then conducted, which indicates that the DVA-C can not only serve as an educational instrument and key technology test bed, but also be applied for scientific work such as pulsar timing, all-sky HI survey, multi-frequency monitoring of variable sources etc.

  12. First results of connected parabolic collector to the grid with Stirling motor in the Seville Engineering School; Primeros resultados de la conexion a red de un disco parabolico con motor stirling, en la escuela superior de ingenieros de Sevilla

    Energy Technology Data Exchange (ETDEWEB)

    Silva Perez, M. A.; Lilio Bravo, I.; Ruiz Hernandez, V.; Larraneta Gomez-Caminero, C.

    2004-07-01

    A Parabolic Dish System has been installed and is operating since March 2004 at the Seville Engineering School (Escuela Superior de Ingenieros). The system is integrated in a wider project, called EnviroDish, that includes the installation of several units in different countries with the aim to gather reliable data on system performance and installation and O and M costs. The system is connected to the grid and the electricity generated is sold to the regional utility with the benefits of the Special Regime. In the present paper we describe the installation and present an advance of the firs operating results. (Author)

  13. International Workshop on Elliptic and Parabolic Equations

    CERN Document Server

    Schrohe, Elmar; Seiler, Jörg; Walker, Christoph

    2015-01-01

    This volume covers the latest research on elliptic and parabolic equations and originates from the international Workshop on Elliptic and Parabolic Equations, held September 10-12, 2013 at the Leibniz Universität Hannover. It represents a collection of refereed research papers and survey articles written by eminent scientist on advances in different fields of elliptic and parabolic partial differential equations, including singular Riemannian manifolds, spectral analysis on manifolds, nonlinear dispersive equations, Brownian motion and kernel estimates, Euler equations, porous medium type equations, pseudodifferential calculus, free boundary problems, and bifurcation analysis.

  14. Analysis of the Quality of Parabolic Flight

    Science.gov (United States)

    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. CPV semi-dense array design for dish and tower collectors

    Science.gov (United States)

    Hayden, Herb; Thomas, Paul; Fette, Nicholas; Farkas, Zoltan; Bading, Michael; Stone, Bradley; Miner, Mark; Stickroth, Oliver; Bagewadi, Nakul; Romero, Memo; Sonuparlak, Birol; Eichholz, Rainer; Ziegler, Michael; Pawlowski, Edgar

    2012-10-01

    SST is developing a new Dish CPV dense array system that overcomes the flux uniformity requirement of previous designs. The ability to operate without flux uniformity relaxes the precision requirements of primary collector optics and eliminates homogenizing optics previously required for dense array CPV. Array design can be configured for dish and tower/heliostat systems developed for thermal CSP applications. The design uses industry standard CPV cells and manufacturing materials and methods for minimum cost and high reliability. Nominal input flux to the array for full power is about 250 suns. Internal array optics increase flux to the cells to about 1200 suns. Linear optics provide additional concentration, permit novel use of commercial glass production methods and facilitate power collection design that is integrated with dynamic power conversion and maximum power point tracking (MPPT). Efficient power hybrid packaging methods are used along with advanced liquid cooling "cold-plate" thermal management. Byproduct "waste heat" can be provided for on-site CHP use. We report on the design approach and status of development with the beginning of on-sun alpha testing of the first of 50 kW of CPV modules being produced.

  16. Homogenization of a nonlinear degenerate parabolic equation

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The homogenization of one kind of nonlinear parabolic equation is studied. The weak convergence and corrector results are obtained by combining carefully the compactness method and two-scale convergence method in the homogenization theory.

  17. Reflective Properties of a Parabolic Mirror.

    Science.gov (United States)

    Ramsey, Gordon P.

    1991-01-01

    An incident light ray parallel to the optical axis of a parabolic mirror will be reflected at the focal point and vice versa. Presents a mathematical proof that uses calculus, algebra, and geometry to prove this reflective property. (MDH)

  18. POSITIVE EQUILIBRIUM SOLUTIONS OF SEMILINEAR PARABOLIC EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The author studies semilinear parabolic equations with initial and periodic boundary value conditions. In the presence of non-well-ordered sub- and super-solutions:"subsolution (≤) supersolution", the existence and stability/instability of equilibrium solutions are obtained.

  19. Partial differential equations of parabolic type

    CERN Document Server

    Friedman, Avner

    2008-01-01

    This accessible and self-contained treatment provides even readers previously unacquainted with parabolic and elliptic equations with sufficient background to understand research literature. Author Avner Friedman - Director of the Mathematical Biosciences Institute at The Ohio State University - offers a systematic and thorough approach that begins with the main facts of the general theory of second order linear parabolic equations. Subsequent chapters explore asymptotic behavior of solutions, semi-linear equations and free boundary problems, and the extension of results concerning fundamenta

  20. Steadily translating parabolic dissolution fingers

    CERN Document Server

    Kondratiuk, Paweł

    2015-01-01

    Dissolution fingers (or wormholes) are formed during the dissolution of a porous rock as a result of nonlinear feedbacks between the flow, transport and chemical reactions at pore surfaces. We analyze the shapes and growth velocities of such fingers within the thin-front approximation, in which the reaction is assumed to take place instantaneously with the reactants fully consumed at the dissolution front. We concentrate on the case when the main flow is driven by the constant pressure gradient far from the finger, and the permeability contrast between the inside and the outside of the finger is finite. Using Ivantsov ansatz and conformal transformations we find the family of steadily translating fingers characterized by a parabolic shape. We derive the reactant concentration field and the pressure field inside and outside of the fingers and show that the flow within them is uniform. The advancement velocity of the finger is shown to be inversely proportional to its radius of curvature in the small P\\'{e}clet...

  1. A 32 m Parabolic Antenna in Peru At 3,370m of Altitude

    CERN Document Server

    Ishitsuka, J; Kaifu, N; Miyama, S; Inoue, M; Tsuboi, M; Ohishi, M; Fujisawa, K; Kasuga, T; Miyazawa, K; Horiuchi, S

    2005-01-01

    At the altitude of 3,370 m on the Peruvian Andes, a 32m antenna owned by the telecommunications company Telefonica del Peru will be transformed to a Radio Telescope, it would be transferred to the Geophysical Institute of Peru (IGP). The parabolic antenna was constructed in 1984 by Nippon Electric Co. (NEC) and worked as an INTELSAT station until 2000. A team of the National Observatory of Japan (NAOJ) evaluated the antenna in 2003 and reported its availability to be used as a Radio Telescope. In collaboration of the NAOJ a 6.7 GHz receiver is under construction and will be installed within this year. Initially the telescope as a single dish will monitor and survey Methanol Maser of YSO, higher frequencies equipment and VLBI instruments will be considered. The antenna will be managed by the IGP and used by universities in Peru, becoming a VLBI station will be a grate contribution to astronomy and geodetic community.

  2. Combined Heat & Power Using the Infinia Concentrated Solar - CHP PowerDish System

    Science.gov (United States)

    2013-08-01

    installed cost as the PowerDish CHP system). The solar thermal system selected and installed will be a low or medium-temperature collector system...implementing the PowerDish CHP. ...................................... 29 Table 8. Important costs for implementing the PowerDish CHP versus PV- solar thermal ...capabilities of the Infinia PowerDish CHP technology to generate clean solar electricity as well as thermal energy for domestic hot water and space

  3. Large mass self-similar solutions of the parabolic-parabolic Keller-Segel model of chemotaxis.

    Science.gov (United States)

    Biler, Piotr; Corrias, Lucilla; Dolbeault, Jean

    2011-07-01

    In two space dimensions, the parabolic-parabolic Keller-Segel system shares many properties with the parabolic-elliptic Keller-Segel system. In particular, solutions globally exist in both cases as long as their mass is less than a critical threshold M(c). However, this threshold is not as clear in the parabolic-parabolic case as it is in the parabolic-elliptic case, in which solutions with mass above M(c) always blow up. Here we study forward self-similar solutions of the parabolic-parabolic Keller-Segel system and prove that, in some cases, such solutions globally exist even if their total mass is above M(c), which is forbidden in the parabolic-elliptic case.

  4. Mineral resource analysis by parabolic fractals

    Institute of Scientific and Technical Information of China (English)

    XIE Shu-yun; YANG Yong-guo; BAO Zheng-yu; KE Xian-zhong; LIU Xiao-long

    2009-01-01

    Elemental concentration distributions in space have been analyzed using different approaches. These analyses are of great significance for the quantitative characterization of various kinds of distribution patterns. Fractal and multi-fiactal methods have been extensively applied to this topic. Traditionally, approximately linear-fractal laws have been regarded as useful tools for characterizing the self-similarities of element concentrations. But, in nature, it is not always easy to fred perfect linear fractal laws. In this paper the parabolic fractal model is used. First a two dimensional multiplicative multi-fractal cascade model is used to study the concentration patterns. The results show the parabolic fractal (PF) properties of the concentrations and the validity of non-linear fractal analysis. By dividing the studied area into four sub-areas it was possible to show that each part follows a non-linear para-bolic fractal law and that the dispersion within each part varies. The ratio of the polynomial coefficients of the fitted parabolic curves can reflect, to some degree, the relative concentration and dispersal distribution patterns. This can provide new insight into the ore-forming potential in space. The parabolic fractal evaluations of ore-forming potential for the four subareas are in good agreement with field investigation work and geochemical mapping results based on analysis of the original data.

  5. Dish concentrators for solar thermal energy - Status and technology development

    Science.gov (United States)

    Jaffe, L. D.

    1981-01-01

    Comparisons are presented of point-focusing, or 'dish' solar concentrator system features, development status, and performance levels demonstrated to date. In addition to the requirements of good optical efficiency and high geometric concentration ratios, the most important future consideration in solar thermal energy dish concentrator design will be the reduction of installed and lifetime costs, as well as the materials and labor costs of production. It is determined that technology development initiatives are needed in such areas as optical materials, design wind speeds and wind loads, structural configuration and materials resistance to prolonged exposure, and the maintenance of optical surfaces. The testing of complete concentrator systems, with energy-converting receivers and controls, is also necessary. Both reflector and Fresnel lens concentrator systems are considered.

  6. FPGA applications for single dish activity at Medicina radio telescopes

    Science.gov (United States)

    Bartolin, M.; Nald, G.; Mattan, A.; Maccaferr, A.; De Biagg, M.

    FPGA technologies are gaining major attention in the recent years in the field of radio astronomy. At Medicina radio telescopes, FPGAs have been used in the last ten years for a number of purposes and in this article we will take into exam the applications developed and installed for the Medicina Single Dish 32m Antenna: these range from high performance digital signal processing to instrument control developed on top of smaller FPGAs.

  7. Thermal Model of a Dish Stirling Cavity-Receiver

    OpenAIRE

    Rubén Gil; Carlos Monné; Nuria Bernal; Mariano Muñoz; Francisco Moreno

    2015-01-01

    This paper presents a thermal model for a dish Stirling cavity based on the finite differences method. This model is a theoretical tool to optimize the cavity in terms of thermal efficiency. One of the main outcomes of this work is the evaluation of radiative exchange using the radiosity method; for that purpose, the view factors of all surfaces involved have been accurately calculated. Moreover, this model enables the variation of the cavity and receiver dimensions and the materials to deter...

  8. Searching for WISPy cold dark matter with a dish antenna

    Energy Technology Data Exchange (ETDEWEB)

    Horns, Dieter [Hamburg Univ. (Germany). Inst. fuer Experimentalphysik; Jaeckel, Joerg [Heidelberg Univ. (Germany). Inst. fuer Theoretische Physik; Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Lindner, Axel; Ringwald, Andreas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Lobanov, Andrei [Max-Planck-Institut fuer Radioastronomie, Bonn (Germany); Redondo, Javier [Muenchen Univ. (Germany). Arnold Sommerfeld Center; Max-Planck-Institut fuer Physik, Muenchen (Germany)

    2012-12-15

    The cold dark matter of the Universe may be comprised of very light and very weakly interacting particles, so-called WISPs. Two prominent examples are hidden photons and axion-like particles. In this note we propose a new technique to sensitively search for this type of dark matter with dish antennas. The technique is broadband and allows to explore a whole range of masses in a single measurement.

  9. Searching for WISPy Cold Dark Matter with a Dish Antenna

    CERN Document Server

    Horns, Dieter; Lindner, Axel; Lobanov, Andrei; Redondo, Javier; Ringwald, Andreas

    2012-01-01

    The cold dark matter of the Universe may be comprised of very light and very weakly interacting particles, so-called WISPs. Two prominent examples are hidden photons and axion-like particles. In this note we propose a new technique to sensitively search for this type of dark matter with dish antennas. The technique is broadband and allows to explore a whole range of masses in a single measurement.

  10. Random perturbations of nonlinear parabolic systems

    CERN Document Server

    Beck, Lisa

    2011-01-01

    Several aspects of regularity theory for parabolic systems are investigated under the effect of random perturbations. The deterministic theory, when strict parabolicity is assumed, presents both classes of systems where all weak solutions are in fact more regular, and examples of systems with weak solutions which develop singularities in finite time. Our main result is the extension of a regularity result due to Kalita to the stochastic case. Concerning the examples with singular solutions (outside the setting of Kalita's regularity result), we do not know whether stochastic noise may prevent the emergence of singularities, as it happens for easier PDEs. We can only prove that, for a linear stochastic parabolic system with coefficients outside the previous regularity theory, the expected value of the solution is not singular.

  11. Parabolic flight as a spaceflight analog.

    Science.gov (United States)

    Shelhamer, Mark

    2016-06-15

    Ground-based analog facilities have had wide use in mimicking some of the features of spaceflight in a more-controlled and less-expensive manner. One such analog is parabolic flight, in which an aircraft flies repeated parabolic trajectories that provide short-duration periods of free fall (0 g) alternating with high-g pullout or recovery phases. Parabolic flight is unique in being able to provide true 0 g in a ground-based facility. Accordingly, it lends itself well to the investigation of specific areas of human spaceflight that can benefit from this capability, which predominantly includes neurovestibular effects, but also others such as human factors, locomotion, and medical procedures. Applications to research in artificial gravity and to effects likely to occur in upcoming commercial suborbital flights are also possible. Copyright © 2016 the American Physiological Society.

  12. Parabolic non-diffracting beams: geometrical approach

    Science.gov (United States)

    Sosa-Sánchez, Citlalli Teresa; Silva-Ortigoza, Gilberto; Alejandro Juárez-Reyes, Salvador; de Jesús Cabrera-Rosas, Omar; Espíndola-Ramos, Ernesto; Julián-Macías, Israel; Ortega-Vidals, Paula

    2017-08-01

    The aim of this work is to present a geometrical characterization of parabolic non-diffracting beams. To this end, we compute the corresponding angular spectrum of the separable non-diffracting parabolic beams in order to determine the one-parameter family of solutions of the eikonal equation associated with this type of beam. Using this information, we compute the corresponding wavefronts and caustic, and find that qualitatively the caustic corresponds to the maximum of the intensity pattern and the wavefronts are deformations of conical surfaces.

  13. Controllable parabolic-cylinder optical rogue wave.

    Science.gov (United States)

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

    2014-10-01

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

  14. Fluorescence microscopy imaging of cells with a plasmonic dish integrally molded

    Science.gov (United States)

    Tawa, Keiko; Sasakawa, Chisato; Fujita, Tsuyoshi; Kiyosue, Kazuyuki; Hosokawa, Chie; Nishii, Junji; Oike, Makoto; Kakinuma, Norihiro

    2016-03-01

    A plastic dish with a wavelength-scale periodic structure at a bottom panel was integrally molded and coated with thin metal films. The integrally molded dish called plasmonic dish was applied to bioimaging under a fluorescence microscope. On the plasmonic substrate, the enhanced electric field based on a grating-coupled surface plasmon resonance (GC-SPR) can provide an enhanced fluorescence. In this study, two kinds of cells, human embryonic kidney (HEK) cells and neuronal cells, were observed in our plasmonic dish. Fluorescence images of HEK cells were above 10 times brighter than those obtained on a conventional glass-bottomed dish. Neuronal cells were successfully cultured for 10 d on the plasmonic dish integrally molded, and in fluorescence images with transmitted light, a higher contrast was obtained than in epifluorescence images. The plasmonic dish integrally molded, as well as that fabricated by the UV nanoimprint method, was also found to be useful for sensitive bioimaging.

  15. Asymptotical Properties for Parabolic Systems of Neutral Type

    Institute of Scientific and Technical Information of China (English)

    CUI Bao-tong; HAN Mao-an

    2005-01-01

    Asymptotical properties for the solutions of neutral parabolic systems with Robin boundary conditions were analyzed by using the inequality analysis. The oscillations problems for the neutral parabolic systems were considered and some oscillation criteria for the systems were established.

  16. A NEWTON MULTIGRID METHOD FOR QUASILINEAR PARABOLIC EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    YU Xijun

    2005-01-01

    A combination of the classical Newton Method and the multigrid method, i.e.,a Newton multigrid method is given for solving quasilinear parabolic equations discretized by finite elements. The convergence of the algorithm is obtained for only one step Newton iteration per level. The asymptotically computational cost for quasilinear parabolic problems is O(NNk) similar to multigrid method for linear parabolic problems.

  17. Chernoff's distribution and parabolic partial differential equations

    NARCIS (Netherlands)

    P. Groeneboom; S.P. Lalley; N.M. Temme (Nico)

    2013-01-01

    textabstractWe give an alternative route to the derivation of the distribution of the maximum and the location of the maximum of one-sided and two-sided Brownian motion with a negative parabolic drift, using the Feynman-Kac formula with stopping times. The derivation also uses an interesting

  18. Orbit Connections in a Parabolic Equation.

    Science.gov (United States)

    1983-04-01

    Departamento de Matematica , 13560, Slo Carlos, S.P. Brasil. This research has been supported in part by CAPES-qoordena~io de Aperfeiqoamento de Pessoal...de Nivel Superior , Brasilia, D.F., Brasil under contract Proc. #3056/78. 1k ORBIT CONNECTIONS IN A PARABOLIC EQUATION by Jack K. Hale and Arnaldo S

  19. Stokes' theorem, volume growth and parabolicity

    CERN Document Server

    Valtorta, Daniele

    2010-01-01

    We present some new Stokes'type theorems on complete non-compact manifolds that extend, in different directions, previous work by Gaffney and Karp and also the so called Kelvin-Nevanlinna-Royden criterion for (p-)parabolicity. Applications to comparison and uniqueness results involving the p-Laplacian are deduced.

  20. CONTINUOUS DEPENDENCE FOR A BACKWARD PARABOLIC PROBLEM

    Institute of Scientific and Technical Information of China (English)

    刘继军

    2003-01-01

    We consider a backward parabolic problem arising in the description of the behavior of the toroidal part of the magenetic field in a dynamo problem. In our backward time problem, the media parameters are spatial distributed and the boundary conditions are of the Robin type. For this ill-posed problem, we prove that the solution depends continuously on the initial-time geometry.

  1. Discontinuous mixed covolume methods for parabolic problems.

    Science.gov (United States)

    Zhu, Ailing; Jiang, Ziwen

    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 L(2).

  2. An Approximation of Ultra-Parabolic Equations

    Directory of Open Access Journals (Sweden)

    Allaberen Ashyralyev

    2012-01-01

    Full Text Available The first and second order of accuracy difference schemes for the approximate solution of the initial boundary value problem for ultra-parabolic equations are presented. Stability of these difference schemes is established. Theoretical results are supported by the result of numerical examples.

  3. ANISOTROPIC PARABOLIC EQUATIONS WITH MEASURE DATA

    Institute of Scientific and Technical Information of China (English)

    Li Fengquan; Zhao Huixiu

    2001-01-01

    In this paper, we prove the existence of solutions to anisotropic parabolic equations with right hand side term in the bounded Radon measure M(Q) and the initial condition in M(Ω) or in Lm space (with m "small").

  4. Chernoff's distribution and parabolic partial differential equations

    NARCIS (Netherlands)

    P. Groeneboom; S.P. Lalley; N.M. Temme (Nico)

    2013-01-01

    textabstractWe give an alternative route to the derivation of the distribution of the maximum and the location of the maximum of one-sided and two-sided Brownian motion with a negative parabolic drift, using the Feynman-Kac formula with stopping times. The derivation also uses an interesting relatio

  5. Dish Stirling system integration and test progress report

    Science.gov (United States)

    Haglund, R. A.

    1982-01-01

    The integration and check-out of a complete Dish Solar Stirling Thermal Power System is described. The preliminary results of the tests conducted thus far are presented. The results are very encouraging and show promise of high performance and efficiency. The outstanding performance and durability of the 4-95 Stirling engine was the highlight of this 6 month integration and test activity. Exposure to severe heat, dust, sand and wind during the summer months and heavy rains, high winds, including sand storms and freezing cold in recent months did affected the engine or the receiver in any noticable manner.

  6. Gods, Germs, and Petri Dishes: Toward a Nonsecular Medical Anthropology.

    Science.gov (United States)

    Roberts, Elizabeth F S

    2016-01-01

    This commentary calls on medical anthropology to become programmatically non-secular. Despite recent anthropological critiques of secularity, within and outside of anthropology, most contemporary medical anthropologists continue to leave deities and religiosity out of their examinations of healing practices, especially in their accounts of biomedicine. Through a critical, relational constructionist lens, which traces how all entities are both constructed and real, a non-secular medical anthropology would insist that when deities are part of medical practice, they are integral to analysis. Importantly then, within the symmetrical nature of this same constructionist lens, biomedical entities like germs and petri dishes need to be accounted for just as much as deities.

  7. Spondyloarthritis, diffuse idiopathic skeletal hyperostosis (DISH) and chondrocalcinosis.

    Science.gov (United States)

    Armas, Jácome Brugues; Couto, Ana Rita; Bettencourt, Bruno Filipe

    2009-01-01

    The authors describe the main clinical and radiological findings of common enthesopathic disorders-spondylarthritis (SpA), chondrocalcinosis/calcium pyrophosphate dehydrate crystal deposition disease (CPPD CDD) and diffuse idiopathic skeletal hyperostosis (DISH), stressing similarities and differences which may help in the differential diagnosis. They emphasize the clinical presentation of the "pseudoankylosing spondylitis" forms of CPPD CDD. They also review the most relevant genes and molecular mechanisms associated with these conditions and with another enthesopathic disorder with high prevalence in the Japanese population-ossification of the posterior longitudinal ligament (OPLL).

  8. An analysis on Translation Strategies of Chinese Dishes

    Institute of Scientific and Technical Information of China (English)

    高慧妍

    2013-01-01

    Cuisine culture occupies a pivotal position in nation’s culture especially in China. Chinese cooking has become a link between Chinese people and people from other countries and an important window for them to know Chinese culture. Hence, to translate those Chinese dish names has been put outstandingly to us, not only because this is the need to promote the comity and understanding between them and us, but also the key job to spread our tradition culture to the world. This thesis attempts to have a brief study of Chinese cuisine naming and put forward some translation methods, such as transliteration, domestication, and so on. Without neglecting some related obstacles.

  9. Diffuse idiopathic skeletal hyperostosis (D.I.S.H.

    Directory of Open Access Journals (Sweden)

    F. De Leonardis

    2011-09-01

    Full Text Available Diffuse idiopathic skeletal hyperostosis (D.I.S.H. is a common disorder of unknown aetiology characterized by exuberant hyperostosis of the antero-lateral aspect of the spinal column, that sometimes leads to bone ankilosis, and by ossification of extra-spinal entheses. This condition is often associated with the metabolic derangement of type 2 diabetes. Primary hypertension, its cardiovascular aftereffects and lithiasis are also often present in these patients. D.I.S.H. has to be distinguished from osteoarthritis, althought they often coexist in the same patient. The mean difference lies in the anatomical target of the pathological process, that is represented by articular cartilage in osteoarthritis and by entheses in diffuse idiopathic skeletal hyperostosis. The enthesopathy leads to the ossification of the anterior longitudinal ligament of the spine and causes the formation of flowing osteophytes, while intervertebral disc space is quite preserved in early phases of the disease. Symptoms of spine involvement are not typical of the disease and consist of pain and stiffness, usually worsened by inaction and damp. It has also been described the ossification of posterior longitudinal ligament which can lead to medullary canal stenosis. Appendicular skeleton is symmetrically involved in early phases of the disease, the most distinctive affected sites being feet, olecranus and patella. Hip involvement is also frequent and may lead to severe disability and represents an important cause of invalidity. The purpose of the present review is to remark on aetiopathogenetic and clinical aspects of diffuse idiopathic skeletal hyperostosis.

  10. AZ-TH, 80 KWE Solar Dish-Stirling Facility

    Energy Technology Data Exchange (ETDEWEB)

    Osuna, R.; Enrile, J.; Sanchez, M.; Fernandez-Quero, V.; Barragan, J.; Ruiz, V.; Silva, M.; Bas, F.; Lopez-Lara, G.; Fernandez-Liebre, F.

    2006-07-01

    Ing. Jose Barragan, Solucar R and D, Avda. Buhaira 2, E-41018 Sevilla, Spain, Tel: +34 95 4937111; Fax: +34 95 4937008; jose.barragan@solucarrd.abengoa.com Abstract. An initiative to promote a 80kWe dish-stirling facility is being carried out by Solucar, an Abengoa company working on solar energy, with the support of the Renewable Energies Program of Andalusia Government TROUGH the Agencia de Innovacion (IDEA), and the Agencia Andaluza de la Energia (AAE). The plant consists of 7 stirling dishes of 11,2kWe unitary power, that will generate 104MWh of electricity in a year, and will sell it to the grid in a commercial basis under the frame of solar thermal renewable energy production regulations in Spain, that consider up to 0,18/kWh over pool market price for electricity. To achieve the feasibility of the project, a new concentrator based on single spherical 0,5 m2 curved mirrors has been proposed. It has been developed following the schemes of the traditional pedestal/arms heliostats. Foreseen cost for concentrator reaches 450/m2 when completely installed and in operation. The facility will be installed in the area of PS10 and Sevilla PV plants, in the solar park that Abengoa is promoting in Sanlucar la Mayor, in order to share maintenance, supervision, vigilance and operation costs with other bigger plants. (Author)

  11. A detailed radiation heat transfer study of a dish-Stirling receiver: The impact of cavity wall radiation properties and cavity shapes

    Science.gov (United States)

    Garrido, Jorge; Wang, Wujun; Nilsson, Martin; Laumert, Björn

    2016-05-01

    A detailed 3-D radiation analysis of a dish-Stirling cavity receiver is carried out to estimate the cavity steady-state temperatures in order to assess the receiver integrity, lifetime and efficiency performance. For this purpose, a parabolic dish was modeled with 5.2 m focal length, 8.85 m aperture diameter and 2 mrad surface error. Three generic cavity shapes (cylindrical, diamond-shaped and reverse-conical) with three different emissivities (0.2, 0.4 and 0.7) are studied. Worst-case scenario heat generations (total absorbed radiation), maximum steady-state temperatures and energy balances of the cavities are calculated to evaluate the receiver performance. The results show that reverse-conical cavities can significantly reduce cavity wall peak temperatures (by 40-120 K), improve the temperature evenness and decrease the radiation losses by 4-5%. Regarding radiation properties, low reflectivities present lower steady-state temperatures even for low/moderate direct solar fluxes. Due to the lower temperatures, lower total thermal losses are also expected.

  12. Combined Heat & Power Using the Infinia Concentrated Solar CHP PowerDish System

    Science.gov (United States)

    2013-08-01

    FINAL REPORT Combined Heat & Power Using the Infinia Concentrated Solar CHP PowerDish System ESTCP Project EW-201145 AUGUST 2013...Combined Heat & Power Using the Infinia Concentrated Solar CHP PowerDish System 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...demonstrated the capabilities of the Infinia PowerDish? CHP technology to generate clean solar thermal and electric energy compatible with domestic and

  13. The Nonlinear Instability Modes of Dished Shallow Shells under Circular Line Loads

    OpenAIRE

    Liu Chang-Jiang; Zheng Zhou-Lian; Huang Cong-Bing; He Xiao-Ting; Sun Jun-Yi; Chen Shan-Lin

    2011-01-01

    This paper investigated the nonlinear stability problem of dished shallow shells under circular line loads. We derived the dimensionless governing differential equations of dished shallow shell under circular line loads according to the nonlinear theory of plates and shells and solved the governing differential equations by combing the free-parameter perturbation method (FPPM) with spline function method (SFM) to analyze the nonlinear instability modes of dished shallow shell under circular l...

  14. Regional food dishes in the Brazilian National School Food Program: Acceptability and nutritional composition

    Directory of Open Access Journals (Sweden)

    Diogo thimoteo da Cunha

    2014-08-01

    Full Text Available Objective: the objective of this study was to evaluate the nutritional composition and describe the acceptability of regional culinary dishes served to students from public schools of rural and urban areas. Methods: Ten Brazilian regional dishes were evaluated for acceptability and nutritional composition. the survey was conducted in schools located in rural and urban areas of two cities in the state of São Paulo. Dish acceptability was evaluated using leftover analysis and a 5-point facial hedonic scale. the adherence index was calculated and used as an indirect measure of acceptance, and the nutritional composition was calculated based on the technical files of each dish. Results: A total of 2,384 students from 20 schools participated in the study and 1,174 tasted and evaluated the dishes. the test using the 5-point facial hedonic scale demonstrated that five dishes (Caldo verde soup, persimmon jelly, chicken with okra, puréed cornmeal with spinach, and arugula pizza had an acceptability rate above 85.0%. the mean adherence indices were 57.3% and 55.6% in urban and rural environments, respectively. Analysis of the nutritional composition of regional dishes indicates that these dishes can partially meet macronutrient recommendations. Conclusion: the tested dishes can become part of school menus as they were accepted or partly accepted by the students regardless of school location, whether rural or urban. the cultural heritage is an important resource for the food sovereignty of a country and should be constantly encouraged.

  15. Who dares to join a parabolic flight?

    Science.gov (United States)

    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.

  16. Antiperiodic Problems for Nonautonomous Parabolic Evolution Equations

    Directory of Open Access Journals (Sweden)

    R. N. Wang

    2014-01-01

    Full Text Available This work focuses on the antiperiodic problem of nonautonomous semilinear parabolic evolution equation in the form u′(t=A(tu(t+f(t,u(t, t∈R, u(t+T=-u(t, t∈R, where (Att∈R (possibly unbounded, depending on time, is a family of closed and densely defined linear operators on a Banach space X. Upon making some suitable assumptions such as the Acquistapace and Terreni conditions and exponential dichotomy on (Att∈R, we obtain the existence results of antiperiodic mild solutions to such problem. The antiperiodic problem of nonautonomous semilinear parabolic evolution equation of neutral type is also considered. As sample of application, these results are applied to, at the end of the paper, an antiperiodic problem for partial differential equation, whose operators in the linear part generate an evolution family of exponential stability.

  17. Moving interfaces and quasilinear parabolic evolution equations

    CERN Document Server

    Prüss, Jan

    2016-01-01

    In this monograph, the authors develop a comprehensive approach for the mathematical analysis of a wide array of problems involving moving interfaces. It includes an in-depth study of abstract quasilinear parabolic evolution equations, elliptic and parabolic boundary value problems, transmission problems, one- and two-phase Stokes problems, and the equations of incompressible viscous one- and two-phase fluid flows. The theory of maximal regularity, an essential element, is also fully developed. The authors present a modern approach based on powerful tools in classical analysis, functional analysis, and vector-valued harmonic analysis. The theory is applied to problems in two-phase fluid dynamics and phase transitions, one-phase generalized Newtonian fluids, nematic liquid crystal flows, Maxwell-Stefan diffusion, and a variety of geometric evolution equations. The book also includes a discussion of the underlying physical and thermodynamic principles governing the equations of fluid flows and phase transitions...

  18. A short proof of increased parabolic regularity

    Directory of Open Access Journals (Sweden)

    Stephen Pankavich

    2015-08-01

    Full Text Available We present a short proof of the increased regularity obtained by solutions to uniformly parabolic partial differential equations. Though this setting is fairly introductory, our new method of proof, which uses a priori estimates and an inductive method, can be extended to prove analogous results for problems with time-dependent coefficients, advection-diffusion or reaction diffusion equations, and nonlinear PDEs even when other tools, such as semigroup methods or the use of explicit fundamental solutions, are unavailable.

  19. Building a parabolic solar concentrator prototype

    Energy Technology Data Exchange (ETDEWEB)

    Escobar-Romero, J F M; Montiel, S Vazquez y; Granados-AgustIn, F; Rodriguez-Rivera, E; Martinez-Yanez, L [INAOE, Luis Enrique Erro 1, Tonantzintla, Pue., 72840 (Mexico); Cruz-Martinez, V M, E-mail: jfmescobar@yahoo.com [Universidad Tecnologica de la Mixteca, Camino a Acatilma Km 2.5, Huajuapan de Leon, Oax., 69000 (Mexico)

    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.

  20. Parabolic cylinder functions of large order

    Science.gov (United States)

    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.

  1. INVERSE COEFFICIENT PROBLEMS FOR PARABOLIC HEMIVARIATIONAL INEQUALITIES

    Institute of Scientific and Technical Information of China (English)

    Liu Zhenhai; I.Szántó

    2011-01-01

    This paper is devoted to the class of inverse problems for a nonlinear parabolic hemivariational inequality.The unknown coefficient of the operator depends on the gradient of the solution and belongs to a set of admissible coefficients.It is proved that the convergence of solutions for the corresponding direct problems continuously depends on the coefficient convergence.Based on this result the existence of a quasisolution of the inverse problem is obtained.

  2. Study on a Cross Diffusion Parabolic System

    Institute of Scientific and Technical Information of China (English)

    Li Chen; Ling Hsiao; Gerald Warnecke

    2007-01-01

    This paper considers a kind of strongly coupled cross diffusion parabolic system, which can be used as the multi-dimensional Lyumkis energy transport model in semiconductor science. The global existence and large time behavior are obtained for smooth solution to the initial boundary value problem. When the initial data are a small perturbation of an isothermal stationary solution, the smooth solution of the problem under the insulating boundary condition, converges to that stationary solution exponentially fast as time goes to infinity.

  3. Controllability of nonlinear degenerate parabolic cascade systems

    Directory of Open Access Journals (Sweden)

    Mamadou Birba

    2016-08-01

    Full Text Available This article studies of null controllability property of nonlinear coupled one dimensional degenerate parabolic equations. These equations form a cascade system, that is, the solution of the first equation acts as a control in the second equation and the control function acts only directly on the first equation. We prove positive null controllability results when the control and a coupling set have nonempty intersection.

  4. Parabolic resection for mitral valve repair.

    Science.gov (United States)

    Drake, Daniel H; Drake, Charles G; Recchia, Dino

    2010-02-01

    Parabolic resection, named for the shape of the cut edges of the excised tissue, expands on a common 'trick' used by experienced mitral surgeons to preserve tissue and increase the probability of successful repair. Our objective was to describe and clinically analyze this simple modification of conventional resection. Thirty-six patients with mitral regurgitation underwent valve repair using parabolic resection in combination with other techniques. Institution specific mitral data, Society of Thoracic Surgeons data and preoperative, post-cardiopulmonary bypass (PCPB) and postoperative echocardiography data were collected and analyzed. Preoperative echocardiography demonstrated mitral regurgitation ranging from moderate to severe. PCPB transesophageal echocardiography demonstrated no regurgitation or mild regurgitation in all patients. Thirty-day surgical mortality was 2.8%. Serial echocardiograms demonstrated excellent repair stability. One patient (2.9%) with rheumatic disease progressed to moderate regurgitation 33 months following surgery. Echocardiography on all others demonstrated no or mild regurgitation at a mean follow-up of 22.8+/-12.8 months. No patient required mitral reintervention. Longitudinal analysis demonstrated 80% freedom from cardiac death, reintervention and greater than moderate regurgitation at four years following repair. Parabolic resection is a simple technique that can be very useful during complex mitral reconstruction. Early and intermediate echocardiographic studies demonstrate excellent results.

  5. Simulation of parabolic reflectors for ultraviolet phototherapy

    Science.gov (United States)

    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.

  6. Simulation of parabolic reflectors for ultraviolet phototherapy.

    Science.gov (United States)

    Robert Grimes, David

    2016-08-21

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

  7. The dish-Rankine SCSTPE program (Engineering Experiment no. 1). [systems engineering and economic analysis for a small community solar thermal electric system

    Science.gov (United States)

    Pons, R. L.; Grigsby, C. E.

    1980-01-01

    Activities planned for phase 2 Of the Small Community Solar Thermal Power Experiment (PFDR) program are summarized with emphasis on a dish-Rankine point focusing distributed receiver solar thermal electric system. Major design efforts include: (1) development of an advanced concept indirect-heated receiver;(2) development of hardware and software for a totally unmanned power plant control system; (3) implementation of a hybrid digital simulator which will validate plant operation prior to field testing; and (4) the acquisition of an efficient organic Rankine cycle power conversion unit. Preliminary performance analyses indicate that a mass-produced dish-Rankine PFDR system is potentially capable of producing electricity at a levelized busbar energy cost of 60 to 70 mills per KWh and with a capital cost of about $1300 per KW.

  8. Status of the Boeing Dish Engine Critical Component Project

    Energy Technology Data Exchange (ETDEWEB)

    Brau, H.W.; Diver, R.B.; Nelving, H.; Stone, K.W.

    1999-01-08

    The Boeing Company's Dish Engine Critical Component (DECC) project started in April of 1998. It is a continuation of a solar energy program started by McDonnell Douglas (now Boeing) and United Stirling of Sweden in the mid 1980s. The overall objectives, schedule, and status of this project are presented in this paper. The hardware test configuration, hardware background, operation, and test plans are also discussed. A summary is given of the test data, which includes the daily power performance, generated energy, working-gas usage, mirror reflectivity, solar insolation, on-sun track time, generating time, and system availability. The system performance based upon the present test data is compared to test data from the 1984/88 McDonnell Douglas/United Stirling AB/Southem California Edison test program. The test data shows that the present power, energy, and mirror performance is comparable to when the hardware was first manufactured 14 years ago.

  9. Dishing up the Data: A Decade of Space Missions

    CERN Document Server

    Sarkissian, John

    2012-01-01

    The past decade has seen Parkes once again involved in a wide range of space tracking activities that have added to its illustrious legacy. This contribution is a personal recollection of those tracking efforts - both real and celluloid. We begin in a light-hearted vein with some behind-the-scenes views of the popular film, "The DISH", and then turn to more serious contributions; discussing the vital role of the telescope in alleviating the great "traffic jam" at Mars in 2003/04 and salvaging the Doppler Wind Experiment as the Huygens probe descended though the atmosphere of Saturn's largest moon, Titan, in mid-decade. We cap off the decade with a discussion of the search for the missing Apollo 11 slow-scan TV tapes.

  10. Analysis Groove Characteristics of Friction Dishes in Wet Speeding Clutch

    Institute of Scientific and Technical Information of China (English)

    HongYue; LiuJin; JinShiliang

    2004-01-01

    The impacts of different groove shapes, numbers, and angle of friction dish on transmitting torque, speed, push pressure in wet speeding clutch are discussed in this paper. Since the wet speeed governing clutch works within hydrodynamic lubrication mixture lubrication. boundary, lubrication and contact situation, the oils combining with a-hydrocarbon or polyester are getting widely used as lubricant.The power-law fluid model with Patir-Cheng average flow model, GT asperity contact model and oil film inertia are applied for average Reynolds equation setting, In order to investigate the relationship between average push pressure within hydrodynamic lubrication and mixture lubrication, average transmitting torque and output speed, the numeral calculation and analysis are presented. According to calculation, it is found that the groove shape, groove angle and groove numbers affect the average transfer torque and push pressure with the speed rate.

  11. Simulations for single-dish intensity mapping experiments

    CERN Document Server

    Bigot-Sazy, M -A; Battye, R A; Browne, I W A; Ma, Y -Z; Maffei, B; Noviello, F; Remazeilles, M; Wilkinson, P N

    2015-01-01

    HI intensity mapping is an emerging tool to probe dark energy. Observations of the redshifted HI signal will be contaminated by instrumental noise, atmospheric and Galactic foregrounds. The latter is expected to be four orders of magnitude brighter than the HI emission we wish to detect. We present a simulation of single-dish observations including an instrumental noise model with 1/f and white noise, and sky emission with a diffuse Galactic foreground and HI emission. We consider two foreground cleaning methods: spectral parametric fitting and principal component analysis. For a smooth frequency spectrum of the foreground and instrumental effects, we find that the parametric fitting method provides residuals that are still contaminated by foreground and 1/f noise, but the principal component analysis can remove this contamination down to the thermal noise level. This method is robust for a range of different models of foreground and noise, and so constitutes a promising way to recover the HI signal from the ...

  12. Thermal Model of a Dish Stirling Cavity-Receiver

    Directory of Open Access Journals (Sweden)

    Rubén Gil

    2015-01-01

    Full Text Available This paper presents a thermal model for a dish Stirling cavity based on the finite differences method. This model is a theoretical tool to optimize the cavity in terms of thermal efficiency. One of the main outcomes of this work is the evaluation of radiative exchange using the radiosity method; for that purpose, the view factors of all surfaces involved have been accurately calculated. Moreover, this model enables the variation of the cavity and receiver dimensions and the materials to determine the optimal cavity design. The tool has been used to study the cavity optimization regarding geometry parameters and material properties. Receiver absorptivity has been identified as the most influential property of the materials. The optimal aperture height depends on the minimum focal space.

  13. Femtosecond parabolic pulse shaping in normally dispersive optical fibers.

    Science.gov (United States)

    Sukhoivanov, Igor A; Iakushev, Sergii O; Shulika, Oleksiy V; Díez, Antonio; Andrés, Miguel

    2013-07-29

    Formation of parabolic pulses at femtosecond time scale by means of passive nonlinear reshaping in normally dispersive optical fibers is analyzed. Two approaches are examined and compared: the parabolic waveform formation in transient propagation regime and parabolic waveform formation in the steady-state propagation regime. It is found that both approaches could produce parabolic pulses as short as few hundred femtoseconds applying commercially available fibers, specially designed all-normal dispersion photonic crystal fiber and modern femtosecond lasers for pumping. The ranges of parameters providing parabolic pulse formation at the femtosecond time scale are found depending on the initial pulse duration, chirp and energy. Applicability of different fibers for femtosecond pulse shaping is analyzed. Recommendation for shortest parabolic pulse formation is made based on the analysis presented.

  14. Dependency of dishing on polish time and slurry chemistry in Cu CMP

    NARCIS (Netherlands)

    Nguyen Hoang, V.; van Kranenburg, H.; Woerlee, P.H.

    2000-01-01

    In this paper the influences of slurry chemistry and thickness of the copper layer on dishing will be discussed. The dishing is studied for different patterns and variable polishing times. We found that the concentration of the oxidiser and the thickness of copper layer have a strong impact on

  15. On Approaches to C-E Translation of Chinese Dish Names

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zi-shun

    2015-01-01

    Literal translation and free translation are the most common methods of translation. It may be accepted that either the two methods or one, or neither on account of the different understandings of the two methods. The author tries to probe into some approaches to C-E translation of Chinese dish names according to the contrastive studies between Chinese and English dish names.

  16. Dish Stirling High Performance Thermal Storage FY14Q3 Quad Chart.

    Energy Technology Data Exchange (ETDEWEB)

    Andraka, Charles E. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2014-07-01

    The project goals are: demonstrate the feasibility of significant thermal storage for dish Stirling systems to leverage their existing high performance to greater capacity; demonstrate key components of a latent storage and transport system enabling on-dish storage with low exergy losses; an provide technology path to a 25kWe system with 6 hours of storage.

  17. Dependency of dishing on polish time and slurry chemistry in Cu CMP

    NARCIS (Netherlands)

    Nguyen, V.; Kranenburg, van H.; Woerlee, P.

    2000-01-01

    In this paper the influences of slurry chemistry and thickness of the copper layer on dishing will be discussed. The dishing is studied for different patterns and variable polishing times. We found that the concentration of the oxidiser and the thickness of copper layer have a strong impact on dishi

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

    Science.gov (United States)

    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.

  19. Measurement of Liquid Viscosities in Tapered or Parabolic Capillaries.

    Science.gov (United States)

    Ershov; Zorin; Starov

    1999-08-01

    The possibility of using tapered or parabolic capillaries for measurement of liquid viscosities is investigated both experimentally and theoretically. It is demonstrated that even small deviations in capillary radius from a constant value may substantially affect measurement results. Equations are derived which allow correct analysis of the measurement results in tapered or parabolic capillaries. The following cases are analyzed: a water imbibition into a tapered or parabolic capillary and displacement of one liquid by another immiscible liquid in tapered or parabolic capillaries. Two possibilities are considered: (a) the narrow end of the capillary as capillary inlet and (b) the wide end of the capillary as capillary inlet. Copyright 1999 Academic Press.

  20. Solar-geothermal hybrid system

    Energy Technology Data Exchange (ETDEWEB)

    Lentz, Alvaro; Almanza, Rafael [Instituto de Ingenieria, UNAM, Ciudad Universitaria, Edificio 12, 04510 Mexico DF (Mexico)

    2006-10-15

    The Cerro Prieto Geothermal Power Plant is located in the northwest of Mexico, lat. 32{sup o}39', long. 115{sup o}21' in the northern hemisphere. A solar-geothermal hybrid system is proposed in order to increase the steam flow during the present geothermal cycle, adding a solar field of parabolic trough concentrators. Energy is supplied to the geothermal flow from wells in order to increase the steam generation rate. This configuration will increase the capacity factor of the system by generating additional steam during the peak demand hours. The parabolic trough solar field is evaluated in North-South and East-West orientation collector alignments. A proposal to obtain an increase of 10% in steam flow is evaluated, as the increase in flow is limited by the content of dissolved salts, so as to avoid a liquid phase with high salt concentrations. The size of the parabolic troughs field was obtained. (author)

  1. Space Debris Radar Experiments at the Medicina VLBI Dish

    Science.gov (United States)

    Pupillo, G.; Montebugnoli, S.; Di Martino, M.; Salerno, E.; Bartolini, M.; Pluchino, S.; Schilliro, F.; Anselmo, L.; Portelli, C.; Konovalenko, A.; Nabatov, A.

    2009-03-01

    In 2007 three space debris detection tests were performed in the framework of a monitoring program carried out by the Istituto Nazionale di Astrofisica - INAF - in collaboration with the Italian Space Agency - ASI. The observations were made by using the bistatic radar technique. The INAF 32 m radiotelescope located at Medicina (Bologna, Italy) was used as receiver whereas the Ukrainian 70 m parabolic antenna located at Evpatoria was utilized as transmitter. The aim of the experiment was to test the sensitivity of the Medicina-Evpatoria radar system in space debris detection, and to validate and optimize the hardware setup. Measurements were mainly carried out on inactive satellites and catalogued space debris. However the search for new fragments in LEO was also performed during the campaign. This paper reports on results of these observations.

  2. Comparison of resonant tunneling in AlGaAs/GaAs parabolic and diffusion modified quantum wells

    Indian Academy of Sciences (India)

    Sudhira Panda; B K Panda; S Fung

    2003-07-01

    Double barrier resonant tunneling diode using annealing induced diffusion modified quantum well is proposed as a viable alternative to that using parabolic quantum well which requires complex techniques to fabricate it. The transmission coefficients are calculated using the hybrid incremental airy function plane wave approach. The room temperature current–voltage characteristics have been calculated using transmission coefficients. The current–voltage characteristics are found to be similar in both diodes.

  3. Diffuse Idiopathic Skeletal Hyperostosis (DISH) and Impaired Physical Function: The Rancho Bernardo Study.

    Science.gov (United States)

    Katzman, Wendy B; Huang, Mei-Hua; Kritz-Silverstein, Donna; Barrett-Connor, Elizabeth; Kado, Deborah M

    2017-07-01

    Investigate associations of diffuse idiopathic skeletal hyperostosis (DISH) with self-reported and measured physical function in older adults. Cross-sectional analyses of data collected in 1992-96 from a longitudinal cohort. Research clinic within a community. Community-dwelling men (n = 630) and women (n = 961), mean age 71.5 years (SD = 10.8), from the Rancho Bernardo Study. DISH assessed from lateral thoracic and lumbar spine radiographs; self-reported difficulty bending over to the floor, walking 2-3 level blocks, or climbing 1 flight of stairs; performance-based measures of grip strength and chair-stand testing (ability to stand up and sit down in a chair 5 times without using chair arms). DISH was present in 25.6% of men and 5.5% of women. In age and sex-adjusted models, those with DISH had 1.72-fold increased odds (95% CI: 1.13, 2.62) of self-reported difficulty bending; this remained significant after further adjustment for Cobb angle, weight, stroke, arthritis, and exercise, OR = 1.69, (95% CI: 1.07, 2.66). In fully adjusted multivariate models, those with DISH had worse grip strength, -1.08 kg, P = .01, but did not differ from those without DISH on walking or climbing stairs. In sex-stratified, fully adjusted models, among men only, those with DISH were 2.17-times (95% CI: 1.04, 4.52) more likely to be unable to complete 5 chair stands without using their arms. DISH was less prevalent in women but affected almost one-quarter of older white men. People with DISH are more likely to experience physical functional impairment, suggesting that DISH has clinical correlations and is not an incidental radiographic finding. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

  4. Optimal Wentzell Boundary Control of Parabolic Equations

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Yousong, E-mail: yousong.luo@rmit.edu.au [RMIT University, School of Mathematical and Geospatial Sciences (Australia)

    2017-04-15

    This paper deals with a class of optimal control problems governed by an initial-boundary value problem of a parabolic equation. The case of semi-linear boundary control is studied where the control is applied to the system via the Wentzell boundary condition. The differentiability of the state variable with respect to the control is established and hence a necessary condition is derived for the optimal solution in the case of both unconstrained and constrained problems. The condition is also sufficient for the unconstrained convex problems. A second order condition is also derived.

  5. Linear Parabolic Maps on the Torus

    CERN Document Server

    Zyczkowski, K; Zyczkowski, Karol; Nishikawa, Takashi

    1999-01-01

    We investigate linear parabolic maps on the torus. In a generic case these maps are non-invertible and discontinuous. Although the metric entropy of these systems is equal to zero, their dynamics is non-trivial due to folding of the image of the unit square into the torus. We study the structure of the maximal invariant set, and in a generic case we prove the sensitive dependence on the initial conditions. We study the decay of correlations and the diffusion in the corresponding system on the plane. We also demonstrate how the rationality of the real numbers defining the map influences the dynamical properties of the system.

  6. Surface roughness estimation of a parabolic reflector

    CERN Document Server

    Casco, Nicolás A

    2010-01-01

    Random surface deviations in a reflector antenna reduce the aperture efficiency. This communication presents a method for estimating the mean surface deviation of a parabolic reflector from a set of measured points. The proposed method takes into account systematic measurement errors, such as the offset between the origin of reference frame and the vertex of the surface, and the misalignment between the surface rotation axis and the measurement axis. The results will be applied to perform corrections to the surface of one of the 30 m diameter radiotelescopes at the Instituto Argentino de Radioastronom\\'ia (IAR).

  7. Parabolic dunes in north-eastern Brazil

    CERN Document Server

    Duran, O; Bezerra, L J C; Herrmann, H J; Maia, L P

    2007-01-01

    In this work we present measurements of vegetation cover over parabolic dunes with different degree of activation along the north-eastern Brazilian coast. We are able to extend the local values of the vegetation cover density to the whole dune by correlating measurements with the gray-scale levels of a high resolution satellite image of the dune field. The empirical vegetation distribution is finally used to validate the results of a recent continuous model of dune motion coupling sand erosion and vegetation growth.

  8. Alignment method for parabolic trough solar concentrators

    Science.gov (United States)

    Diver, Richard B [Albuquerque, NM

    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.

  9. Routine operation of a parabolic disc with motor Stirling connected to network, in the Technical School Superior of Engineers of Seville; Operacion rutinaria de un disco parabolico con motor stirling conectado a red, en la Escuela Tecnica Superior de Ingenieros de Sevilla

    Energy Technology Data Exchange (ETDEWEB)

    Silva Perez, M. A.; Gavilan Morales, A.; Larraneta Gomez-Caminero, C.; Gonalez Cuenca, I.; Lillo Bravo, I.; Ruiz Hernandez, V.

    2008-07-01

    A 10 kWe Parabolic dish- Stirling engine system was installed at the Seville Engineering School in early 2004. This system is one of the country Reference Units of the EnviroDish project, consisting in the installation and operation of several units, based on the EuroDish system, in different countries aimed to gathering reliable O and M data that help to improve and fine-tune the technology. The Seville Country Reference Unit is connected to the gird. The Seville country Reference Unit has been in operation since March 2004, accumulating 1915 operation hours and 9,7 MWh of electricity production until October 2007. This paper summarizes the results of 32 months of routine operation, with emphasis on O and M aspects and lessons learned during this period. (Author)

  10. SURFACE FINITE ELEMENTS FOR PARABOLIC EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    G. Dziuk; C.M. Elliott

    2007-01-01

    In this article we define a surface finite element method (SFEM) for the numerical solution of parabolic partial differential equations on hypersurfaces Γ in (R)n+1. The key idea is based on the approximation of Γ by a polyhedral surface Γh consisting of a union of simplices (triangles for n = 2, intervals for n = 1) with vertices on Γ. A finite element space of functions is then defined by taking the continuous functions on Γh which are linear affine on each simplex of the polygonal surface. We use surface gradients to define weak forms of elliptic operators and naturally generate weak formulations of elliptic and parabolic equations on Γ. Our finite element method is applied to weak forms of the equations. The computation of the mass and element stiffness matrices are simple and straightforward.We give an example of error bounds in the case of semi-discretization in space for a fourth order linear problem. Numerical experiments are described for several linear and nonlinear partial differential equations. In particular the power of the method is demonstrated by employing it to solve highly nonlinear second and fourth order problems such as surface Allen-Cahn and Cahn-Hilliard equations and surface level set equations for geodesic mean curvature flow.

  11. Focusing parabolic guide for very small samples

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-15

    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.

  12. Focusing parabolic guide for very small samples

    Science.gov (United States)

    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.

  13. A nonlocal parabolic system with application to a thermoelastic problem

    Directory of Open Access Journals (Sweden)

    Y. Lin

    1999-01-01

    problem is first transformed into an equivalent nonlocal parabolic systems using a transformation, and then the existence and uniqueness of the solutions are demonstrated via the theoretical potential representation theory of the parabolic equations. Finally some realistic situations in the applications are discussed using the results obtained in this paper.

  14. Almost Periodic Viscosity Solutions of Nonlinear Parabolic Equations

    Directory of Open Access Journals (Sweden)

    Zhang Shilin

    2009-01-01

    Full Text Available We generalize the comparison result 2007 on Hamilton-Jacobi equations to nonlinear parabolic equations, then by using Perron's method to study the existence and uniqueness of time almost periodic viscosity solutions of nonlinear parabolic equations under usual hypotheses.

  15. Carleman Estimates for Parabolic Equations with Nonhomogeneous Boundary Conditions

    Institute of Scientific and Technical Information of China (English)

    Oleg Yu IMANUVILOV; Jean Pierre PUEL; Masahiro YAMAMOTO

    2009-01-01

    The authors prove a new Carleman estimate for general linear second order parabolic equation with nonhomogeneous boundary conditions.On the basis of this estimate,improved Carleman estimates for the Stokes system and for a system of parabolic equations with a penalty term are obtained.This system can be viewed as an approximation of the Stokes system.

  16. Flux form Semi-Lagrangian methods for parabolic problems

    CERN Document Server

    Bonaventura, Luca

    2015-01-01

    A semi-Lagrangian method for parabolic problems is proposed, that extends previous work by the authors to achieve a fully conservative, flux-form discretization of linear and nonlinear diffusion equations. A basic consistency and convergence analysis are proposed. Numerical examples validate the proposed method and display its potential for consistent semi-Lagrangian discretization of advection--diffusion and nonlinear parabolic problems.

  17. A numerical study of mixed parabolic-gradient systems

    NARCIS (Netherlands)

    Verwer, J.G.; Sommeijer, B.P.

    2000-01-01

    This paper is concerned with the numerical solution of parabolic equations coupled to gradient equations. The gradient equations are ordinary differential equations whose solutions define positions of particles in the spatial domain of the parabolic equations. The vector field of the gradient equati

  18. The parabolic equation method for outdoor sound propagation

    DEFF Research Database (Denmark)

    Arranz, Marta Galindo

    The parabolic equation method is a versatile tool for outdoor sound propagation. The present study has focused on the Cranck-Nicolson type Parabolic Equation method (CNPE). Three different applications of the CNPE method have been investigated. The first two applications study variations...

  19. STABILITY OF A PARABOLIC FIXED POINT OF REVERSIBLE MAPPINGS

    Institute of Scientific and Technical Information of China (English)

    LIUBIN; YOUJIANGONG

    1994-01-01

    KAM theorem of reversible system is used to provide a sufficient condition which guarantees the stability of a parabolic fixed point of reversible mappings, The main idea is to discuss when the parabolic fixed point is surrounded by closed invariant carves and thus exhibits stable behaviour.

  20. On the dynamics of a mixed parabolic-gradient system

    NARCIS (Netherlands)

    J.K. Krottje (Johannes)

    2002-01-01

    textabstractIn the current paper the dynamics of a mixed parabolic-gradient system is examined. Thesystem, which is a coupled system of parabolic equations and gradient equations, acts as a first model for the outgrowth of axons in a developing nervous system. For modeling considerations it is relev

  1. Manipulation of dielectric particles with nondiffracting parabolic beams.

    Science.gov (United States)

    Ortiz-Ambriz, Antonio; Gutiérrez-Vega, Julio C; Petrov, Dmitri

    2014-12-01

    The trapping and manipulation of microscopic particles embedded in the structure of nondiffracting parabolic beams is reported. The particles acquire orbital angular momentum and exhibit an open trajectory following the parabolic fringes of the beam. We observe an asymmetry in the terminal velocity of the particles caused by the counteracting gradient and scattering forces.

  2. Surface plasmon polariton beam focusing with parabolic nanoparticle chains

    DEFF Research Database (Denmark)

    Radko, Ilya P.; Bozhevolnyi, Sergey I.; Evlyukhin, Andrey B.

    2007-01-01

    We report on the focusing of surface plasmon polariton (SPP) beams with parabolic chains of gold nanoparticles fabricated on thin gold films. SPP focusing with different parabolic chains is investigated in the wavelength range of 700–860 nm, both experimentally and theoretically. Mapping of SPP...

  3. Testing of the SAIC facets on the stretched-membrane dish

    Science.gov (United States)

    Grossman, J. W.; Erdman, W. W.; Houser, R. M.; Davenport, R.

    1994-04-01

    A dish structure sized for a 25 kW electric dish/generator system has been installed at the National Solar Thermal Test Facility (NSTTF). The dish is used as an optical test bed for prototype stretched-membrane facets. Sandia procured twelve (12) stretched-membrane facets from Science Applications International Corporation (SAIC) for installation on the dish structure. Individual facet optical performance was measured using the 2f test method under development at Sandia. Four facets were tested on-sun using the test truss at the NSTTF prior to installation on the dish structure. During the final stages of the structure assembly, the facets were installed for testing. A distant light source alignment technique was used to align the facets to a 9 meter focal length. The alignment and focus were optimized with on-sun measurements of individual facet characteristics. On-sun flux maps of the image were made using the Beam Characterization System. Calorimetry tests were performed using a cold water calorimeter. This data was used to create a power intercept curve and predict the power inside apertures of different sizes. The focal plane was moved to 9.95 meters and the alignment, optimization, and on-sun tests repeated. This paper presents the results of the testing on the individual facets as well as the results of testing the dish system. The effects of the change in focal length on the optical performance of the dish are shown in the results.

  4. Polaron Energy and Effective Mass in Parabolic Quantum Wells

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi-Ping; LIANG Xi-Xia

    2005-01-01

    @@ The energy and effective mass of a polaron in a parabolic quantum well are studied theoretically by using LLP-like transformations and a variational approach. Numerical results are presented for the polaron energy and effective mass in the GaAs/Al0.3Ga0.7As parabolic quantum well. The results show that the energy and the effective mass of the polaron both have their maxima in the finite parabolic quantum well but decrease monotonously in the infinite parabolic quantum well with the increasing well width. It is verified that the bulk longitudinal optical phonon mode approximation is an adequate formulation for the electron-phonon coupling in parabolic quantum well structures.

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

    Institute of Scientific and Technical Information of China (English)

    (O)ZT(U)RK Murat; (C)(I)(C)EK BEZ(I)R Nalan; (O)ZEK Nuri

    2007-01-01

    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.

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

    Science.gov (United States)

    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

  7. The Comparison of Photovoltaic with Small Solar Dish Stirling for Solar Home System 50 W{sub p} in Thailand, Medium Insolation Nature

    Energy Technology Data Exchange (ETDEWEB)

    Snidvongs, E. S.; Jindaruj, S.

    2006-07-01

    The Thai government initiated a project entitled Solar Home System which involved the provision of standalone Photovoltaic 50 Wp for houses without transmission lines in remote areas, 300,000 units. These units are provided at a low price with the government supporting half of the cost and the rest paid by the owners in installments. So far, more than 150,000 units have been installed and it is expected that the whole project would be completed by the end of the year 2005. A purpose of this research is to compare the original Thai government's Solar Home PV System with the new 50 Wp Small Solar Thermal Dish Stirling System in terms of their advantages and disadvantages for Thailand. The result of this would serve as a guide for the users to select the most suitable system in terms of price, maintenance, cost, economy, performance, reliability, and efficiency. Such comparison will be presented in the form of descriptive, photographs, statistics, and tables. As for the data involved, part of this is based on active fact such as construction cost, material cost, labor cost, rate of inflation, rate of interest. While some of these derives from the experience of researcher as well as facts and figures from Thai governments publications such as operation and maintenance cost. In addition to that some data are taken from basic experiments conducted either by the various universities and the researcher own laboratory. These include solar insolation, PV data and Stirling engine test with electric heater. And, of course, some data are based on simple estimation and prediction. Thailand is a country of 550 w/m2 with high humidity, soft-land and medium insolation. It locates near the equator at latitude 5 12 N, longitude 96 106 E. By using a parabolic shape satellite dish with solar tracker and a 60 W Four Cylinders gamma type Stirling engine with sinusoidal gear linear link, low offset space, and solid thermal storage to act as buffer between the solar energy and the

  8. A 32 m Parabolic Antenna in Peru at 3,370 m of Altitude

    Science.gov (United States)

    Ishitsuka, J.; Ishitsuka, M.; Kaifu, N.; Miyama, S.; Inoue, M.; Tsuboi, M.; Ohishi, M.; Fujisawa, K.; Kasuga, T.; Miyazawa, K.; Horiuchi, S.

    At the altitude of 3,370 m on the Peruvian Andes, a 32m antenna owned by the telecommunications company Telefónica del Perú will be transformed to a Radio Telescope, it would be transferred to the Geophysical Institute of Peru (IGP). The parabolic antenna was constructed in 1984 by Nippon Electric Co. (NEC) and worked as an INTELSAT station until 2000. A team of the National Observatory of Japan (NAOJ) evaluated the antenna in 2003 and reported its availability to be used as a Radio Telescope. In collaboration of the NAOJ a 6.7 GHz receiver is under construction and will be installed within this year. Initially the telescope as a single dish will monitor and survey Methanol Maser of YSO, higher frequencies equipment and VLBI instruments will be considered. The antenna will be managed by the IGP and used by universities in Peru, becoming a VLBI station will be a grate contribution to astronomy and geodetic community. (astro-ph/0501035)

  9. Concentration phenomena in the semilinear parabolic equation

    Institute of Scientific and Technical Information of China (English)

    TAN; Zhong

    2001-01-01

    [1]Fujita, H., On the blowing up of solutions of the Chauch problem for u=Δu+u1+α, J. Fac. Sci. Univ. Tokyo Sect. I, 966, 3: 09.[2]Ni, W. -M., Sacks, P. E., Tavantzis, J., On the asymptotic behavior of solutions of certain quasilinear equations of parabolic type, J. Differential Equations, 984, 54: 97.[3]Cazenave, T., Lions, P. L., Solutions globales d'equations de la chaleur semilineaires, Comm. in Partial Differential Equations, 984, 9(0): 955.[4]Giga, Y., A bound for global solutions of semilinear heat equations, Commun. Math. Phys., 986, 03: 45.[5]Galaktionov, V., Vazquez, J. L., Continuation of blow-up solutions of nonlinear heat equations in several space dimensions, Comm. Pure Appl. Math., 997, 50: .[6]Rey, O., The role of the Green's function in a nonlinear elliptic equation involving the critical Sobolev exponent, J. Func. Anal., 990, 89: .[7]Wei Juncheng, Asymptotic behavior of least energy solution to a semilinear Dirichlet problem near the critical exponent, J. Math. Soc. Japan, 998, 50(): 39.[8]Lions, P. L., The concentration-compactness principle in the calculus of variations, The limit case ,2, Rev. Mat. Iberoamerioana, 985, : 45, 45.[9]Brezis, H., Elliptic equations with limiting Sobolev exponents——the impact of topology, Commun. Pure and Appl. Math., 986, XXXXIX: S7.[10]Sacks, J., Uhlenbeck, K., The existence of minimal immersions of 2-spheres, Ann. Math., 98, 3: .[11]Zhu Xiping, Nontrivial solutions of quasilinear elliptic equation involving critical growth, Science in China (in Chinese), Ser. A, 988, (3): 225.[12]Pohozaev, S. I., Eigenfunctions of the equation -Δu+λf(u)=0, Soviet. Math. Dold., 965, 6: 408.[13]Gidas, B., Ni, W. -M., Nirenberg, L., Symmetry and related properties via the maximum principle, Comm. Math. Phys., 979, 68: 209.[14]Ni, W. -M., Sacks, P. E., Singular behaviour in nonlinear parabolic equations, Tran. of the AMS, 985, 287(2): 657.[15]Ni, W. -M., Sacks, P. E

  10. Parabolic refined invariants and Macdonald polynomials

    CERN Document Server

    Chuang, Wu-yen; Donagi, Ron; Pantev, Tony

    2013-01-01

    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 G. 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.

  11. Antireflection Pyrex envelopes for parabolic solar collectors

    Science.gov (United States)

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

    1983-11-01

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

  12. Photon-Atom Coupling with Parabolic Mirrors

    CERN Document Server

    Sondermann, Markus

    2014-01-01

    Efficient coupling of light to single atomic systems has gained considerable attention over the past decades. This development is driven by the continuous growth of quantum technologies. The efficient coupling of light and matter is an enabling technology for quantum information processing and quantum communication. And indeed, in recent years much progress has been made in this direction. But applications aside, the interaction of photons and atoms is a fundamental physics problem. There are various possibilities for making this interaction more efficient, among them the apparently 'natural' attempt of mode-matching the light field to the free-space emission pattern of the atomic system of interest. Here we will describe the necessary steps of implementing this mode-matching with the ultimate aim of reaching unit coupling efficiency. We describe the use of deep parabolic mirrors as the central optical element of a free-space coupling scheme, covering the preparation of suitable modes of the field incident on...

  13. Analysis of the Quality of Parabolic Flight

    Science.gov (United States)

    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.

  14. New method to solve electromagnetic parabolic equation

    Institute of Scientific and Technical Information of China (English)

    赵小峰; 黄思训; 康林春

    2013-01-01

    This paper puts forward a new method to solve the electromagnetic parabolic equation (EMPE) by taking the vertically-layered inhomogeneous characteristics of the atmospheric refractive index into account. First, the Fourier transform and the convo-lution theorem are employed, and the second-order partial differential equation, i.e., the EMPE, in the height space is transformed into first-order constant coefficient differential equations in the frequency space. Then, by use of the lower triangular characteristics of the coefficient matrix, the numerical solutions are designed. Through constructing ana-lytical solutions to the EMPE, the feasibility of the new method is validated. Finally, the numerical solutions to the new method are compared with those of the commonly used split-step Fourier algorithm.

  15. Metagenomic data of fungal internal transcribed spacer from serofluid dish, a traditional Chinese fermented food

    Directory of Open Access Journals (Sweden)

    Peng Chen

    2016-03-01

    Full Text Available Serofluid dish (or Jiangshui, in Chinese, a traditional food in the Chinese culture for thousands of years, is made from vegetables by fermentation. In this work, microorganism community of the fermented serofluid dish was investigated by the culture-independent method. The metagenomic data in this article contains the sequences of fungal internal transcribed spacer (ITS regions of rRNA genes from 12 different serofluid dish samples. The metagenome comprised of 50,865 average raw reads with an average of 8,958,220 bp and G + C content is 45.62%. This is the first report on metagenomic data of fungal ITS from serofluid dish employing Illumina platform to profile the fungal communities of this little known fermented food from Gansu Province, China. The Metagenomic data of fungal internal transcribed spacer can be accessed at NCBI, SRA database accession no. SRP067411.

  16. Metagenomic data of fungal internal transcribed spacer from serofluid dish, a traditional Chinese fermented food.

    Science.gov (United States)

    Chen, Peng; Zhao, Yang; Wu, Zhengrong; Liu, Ronghui; Xu, Ruixiang; Yan, Lei; Li, Hongyu

    2016-03-01

    Serofluid dish (or Jiangshui, in Chinese), a traditional food in the Chinese culture for thousands of years, is made from vegetables by fermentation. In this work, microorganism community of the fermented serofluid dish was investigated by the culture-independent method. The metagenomic data in this article contains the sequences of fungal internal transcribed spacer (ITS) regions of rRNA genes from 12 different serofluid dish samples. The metagenome comprised of 50,865 average raw reads with an average of 8,958,220 bp and G + C content is 45.62%. This is the first report on metagenomic data of fungal ITS from serofluid dish employing Illumina platform to profile the fungal communities of this little known fermented food from Gansu Province, China. The Metagenomic data of fungal internal transcribed spacer can be accessed at NCBI, SRA database accession no. SRP067411.

  17. Regional food dishes in the Brazilian National School Food Program: Acceptability and nutritional composition

    National Research Council Canada - National Science Library

    Cunha, Diogo thimoteo da; Gonçalves, Hélida Ventura Barbosa; Lima, Aline Fátima Andrade de; Martins, Paula Andrea; Rosso, Veridiana Vera de; Stedefeldt, Elke

    2014-01-01

    Objective: the objective of this study was to evaluate the nutritional composition and describe the acceptability of regional culinary dishes served to students from public schools of rural and urban areas.Methods...

  18. Temperature gradients drive radial fluid flow in Petri dishes and multiwell plates.

    Science.gov (United States)

    Lindsay, Stephen M; Yin, John

    2016-06-01

    Liquid in a Petri dish spontaneously circulates in a radial pattern, even when the dish is at rest. These fluid flows have been observed and utilized for biological research, but their origins have not been well-studied. Here we used particle-tracking to measure velocities of radial fluid flows, which are shown to be linked to evaporation. Infrared thermal imaging was used to identify thermal gradients at the air-liquid interface and at the bottom of the dish. Two-color ratiometric fluorescence confocal imaging was used to measure thermal gradients in the vertical direction within the fluid. A finite-element model of the fluid, incorporating the measured temperature profiles, shows that buoyancy forces are sufficient to produce flows consistent with the measured particle velocity results. Such flows may arise in other dish or plate formats, and may impact biological research in positive or negative ways.

  19. Sener Parabolic trough Collector Design and Testing

    Energy Technology Data Exchange (ETDEWEB)

    Castaneda, N.; Vazquez, J.; Domingo, M.

    2006-07-01

    Parabolic trough technology is nowadays the most extended solar system for electricity production or steam generation for industrial processes. It is basically composed of a collector field which converts solar irradiation into thermal energy- and a conventional thermal-toelectric conversion Rankine cycle. In these plants, a storage system can be implemented in order to increase plant production. Collector field represents more than half the total plant cost. Therefore, SENER has made an effort to improve current state of the art of parabolic trough collector (PTC from now on) design in order to reduce plant costs. Main characteristic of SENER design lies on the use of a torque tube as the central body of the collector. This tube is made of steel sheet, with a thickness depending on wind load requirements on the collector. This concept is very cost-effective, since the man-power needed to manufacture the tube has been minimized. Continuous cylindrical shape of the torque tube provides a high torsional stiffness, which is one of the main parameters affecting collector optical efficiency. Cantilever arms connect the mirrors to the central torque tube. These components are usually made of welded tube profiles. In SENER's new design, these cantilever arms are made using metal sheet stamping techniques (SENER patent), thus reducing manufacturing and mounting costs. SENER PTC module (called SENERTROUGH) is 12 meters long and has an aperture width of 5,76 m. HCE and curved mirrors existing in the market - as well as new products from different manufacturers - can be easily attached to collector structure. Two prototype modules of SENERTROUGH have been mounted and tested at the CIEMAT-PSA facilities. Several performance tests were performed in order to assure the validity of the concept. (Author)

  20. Technical Status of the Dish/Stirling Joint Venture Program

    Science.gov (United States)

    1995-01-01

    heliostats as the heat input source. Through another NREL program; Thermacore has designed built, and tested a prototype hybrid heat pipe receiver...These subsystems include the solar concentrator, heat pipe receiver, engine/alternator, power conditioning, and automatic controls. 14. SUBJECT...include the solar concentrator, heat pipe receiver, engine/altemator, power conditioning, and automatic controls. INTRODUCTION Initiated in 1991; the

  1. Design, Analysis and Optimization of a Solar Dish/Stirling System

    OpenAIRE

    Seyyed Danial Nazemi; Mehrdad Boroushaki

    2016-01-01

    In this paper, a mathematical model by which the thermal and physical behavior of a solar dish/Stirling system was investigated, then the system was designed, analysed and optimized. In this regard, all of heat losses in a dish/Stirling system were calculated, then, the output net-work of the Stirling engine was computed, and accordingly, the system efficiency was worked out. These heat losses include convection and conduction heat losses, radiation heat losses by emission in the cavity recei...

  2. DISH STIRLING SYSTEM POTENTIAL ASSESSMENT FOR EIGHT MAIN SITES IN MADAGASCAR

    OpenAIRE

    Praene, Jean-Philippe; Radanielina, Harimisa; Rakotondramiarana, Hery Tiana

    2016-01-01

    International audience; Solar energy is a green and attractive renewable energy source that can be converted for power generation. The objective of this work is to evaluate the potential of dish Stirling systems if they are used in the fourth worldwide largest island of Madagascar. For that purpose, a theoretical model of the dish Stirling system based on the geometrical configuration and heat transfer was developed and coded on Matlab. Simulations were run to investigate the energy efficienc...

  3. Faults Analysis and Diagnosis of DR J-460 Dish Centrifugal Separator's Helical Gear

    Institute of Scientific and Technical Information of China (English)

    MA Xiao-jian; GAN Xue-hui

    2004-01-01

    The main faults of dish centrifugal separator's helical gear are described in this paper. In order to diagnose the DR J-460 dish centrifugal separator correctly, the vibration is tested with a helical gear under both normal and abnormal conditions. After comparing several general methods of the gear's fault feature extraction, a new convenient and effective method is presented on the basis of analyzing the vibration spectrum under different rotary velocities.

  4. Dish Stirling High Performance Thermal Storage FY14Q4 Quad Chart

    Energy Technology Data Exchange (ETDEWEB)

    Andraka, Charles E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-10-01

    The goals of this project are to demonstrate the feasibility of significant thermal storage for dish stirling systems to leverage their existing high performance to greater capacity; demonstrate key components of a latent storage and transport system enabling on-dish storage with low energy losses; and provide a technology path to a 25kWe system with 6 hours of storage.

  5. Sterile polystyrene culture dishes induce transformation of polyps into medusae in Aurelia aurita (Scyphozoa, Cnidaria).

    Science.gov (United States)

    Herrmann, Klaus; Siefker, Barbara; Berking, Stefan

    2003-01-01

    Polyps of Aurelia aurita produce medusae once a year. Under laboratory conditions this process, termed strobilation, can be induced by lowering the incubation temperature for about two weeks. Here we report a fast induction of strobilation by sterile polystyrene culture dishes. The effect is abolished when the culture dishes are washed twice with hot water prior to the experiment. We recommend that polystyrene cultureware should be pre-washed whenever there is an indication of unusual effects.

  6. Parabolic features and the erosion rate on Venus

    Science.gov (United States)

    Strom, Robert G.

    1993-01-01

    The impact cratering record on Venus consists of 919 craters covering 98 percent of the surface. These craters are remarkably well preserved, and most show pristine structures including fresh ejecta blankets. Only 35 craters (3.8 percent) have had their ejecta blankets embayed by lava and most of these occur in the Atla-Beta Regio region; an area thought to be recently active. parabolic features are associated with 66 of the 919 craters. These craters range in size from 6 to 105 km diameter. The parabolic features are thought to be the result of the deposition of fine-grained ejecta by winds in the dense venusian atmosphere. The deposits cover about 9 percent of the surface and none appear to be embayed by younger volcanic materials. However, there appears to be a paucity of these deposits in the Atla-Beta Regio region, and this may be due to the more recent volcanism in this area of Venus. Since parabolic features are probably fine-grain, wind-deposited ejecta, then all impact craters on Venus probably had these deposits at some time in the past. The older deposits have probably been either eroded or buried by eolian processes. Therefore, the present population of these features is probably associated with the most recent impact craters on the planet. Furthermore, the size/frequency distribution of craters with parabolic features is virtually identical to that of the total crater population. This suggests that there has been little loss of small parabolic features compared to large ones, otherwise there should be a significant and systematic paucity of craters with parabolic features with decreasing size compared to the total crater population. Whatever is erasing the parabolic features apparently does so uniformly regardless of the areal extent of the deposit. The lifetime of parabolic features and the eolian erosion rate on Venus can be estimated from the average age of the surface and the present population of parabolic features.

  7. Parabolic features and the erosion rate on Venus

    Science.gov (United States)

    Strom, Robert G.

    1993-01-01

    The impact cratering record on Venus consists of 919 craters covering 98 percent of the surface. These craters are remarkably well preserved, and most show pristine structures including fresh ejecta blankets. Only 35 craters (3.8 percent) have had their ejecta blankets embayed by lava and most of these occur in the Atla-Beta Regio region; an area thought to be recently active. parabolic features are associated with 66 of the 919 craters. These craters range in size from 6 to 105 km diameter. The parabolic features are thought to be the result of the deposition of fine-grained ejecta by winds in the dense venusian atmosphere. The deposits cover about 9 percent of the surface and none appear to be embayed by younger volcanic materials. However, there appears to be a paucity of these deposits in the Atla-Beta Regio region, and this may be due to the more recent volcanism in this area of Venus. Since parabolic features are probably fine-grain, wind-deposited ejecta, then all impact craters on Venus probably had these deposits at some time in the past. The older deposits have probably been either eroded or buried by eolian processes. Therefore, the present population of these features is probably associated with the most recent impact craters on the planet. Furthermore, the size/frequency distribution of craters with parabolic features is virtually identical to that of the total crater population. This suggests that there has been little loss of small parabolic features compared to large ones, otherwise there should be a significant and systematic paucity of craters with parabolic features with decreasing size compared to the total crater population. Whatever is erasing the parabolic features apparently does so uniformly regardless of the areal extent of the deposit. The lifetime of parabolic features and the eolian erosion rate on Venus can be estimated from the average age of the surface and the present population of parabolic features.

  8. Parabolic Bundles on Algebraic Surfaces I -- The Donaldson-Uhlenbeck Compactification

    Indian Academy of Sciences (India)

    V Balaji; A Dey; R Parthasarathi

    2008-02-01

    The aim of this paper is to construct the parabolic version of the Donaldson-Uhlenbeck compactification for the moduli space of parabolic stable bundles on an algebraic surface with parabolic structures along a divisor with normal crossing singularities. We prove the non-emptiness of the moduli space of parabolic stable bundles of rank 2.

  9. A Microscopic Convexity Principle for Spacetime Convex Solutions of Fully Nonlinear Parabolic Equations

    Institute of Scientific and Technical Information of China (English)

    Chuan Qiang CHEN; Bo Wen HU

    2013-01-01

    We study microscopic spacetime convexity properties of fully nonlinear parabolic partial differential equations.Under certain general structure condition,we establish a constant rank theorem for the spacetime convex solutions of fully nonlinear parabolic equations.At last,we consider the parabolic convexity of solutions to parabolic equations and the convexity of the spacetime second fundamental form of geometric flows.

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

    Science.gov (United States)

    Hattori, Haroldo T

    2014-10-10

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

  11. Pseudo almost periodic solutions to parabolic boundary value inverse problems

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    We first define the pseudo almost periodic functions in a more general setting.Then we show the existence,uniqueness and stability of pseudo almost periodic solutions of parabolic inverse problems for a type of boundary value problems.

  12. OSCILLATION OF NONLINEAR IMPULSIVE PARABOLIC DIFFERENTIAL EQUATIONS WITH SEVERAL DELAYS

    Institute of Scientific and Technical Information of China (English)

    CuiChenpei; ZouMin; LiuAnping; XiaoLi

    2005-01-01

    In this paper, oscillatory properties for solutions of certain nonlinear impulsive parabolic equations with several delays are investigated and a series of new sufficient conditions for oscillations of the equation are established.

  13. A Note about Parabolic Systems and Analytic Semigroups

    Institute of Scientific and Technical Information of China (English)

    STR?HMER Gerhard

    2011-01-01

    We investigate the question whether certain parabolic systems in the sense of Petrovskii fulfill the resolvent estimate required for the generation of an analytic semigroup and apply the result to a problem concerning the diffusion of gases.

  14. A SINGLE STEP SCHEME WITH HIGH ACCURACY FOR PARABOLIC PROBLEM

    Institute of Scientific and Technical Information of China (English)

    陈传淼; 胡志刚

    2001-01-01

    A single step scheme with high accuracy for solving parabolic problem is proposed. It is shown that this scheme possesses good stability and fourth order accuracy with respect to both time and space variables, which are superconvergent.

  15. Parabolic Equations in Musielak-Orlicz-Sobolev Spaces

    Directory of Open Access Journals (Sweden)

    M.L. Ahmed Oubeid

    2013-11-01

    Full Text Available We prove in this paper the existence of solutions of nonlinear parabolic problems in Musielak-Orlicz-Sobolev spaces. An approximation and a trace results in inhomogeneous Musielak-Orlicz-Sobolev spaces have also been provided.

  16. HYPERBOLIC-PARABOLIC CHEMOTAXIS SYSTEM WITH NONLINEAR PRODUCT TERMS

    Institute of Scientific and Technical Information of China (English)

    Chen Hua; Wu Shaohua

    2008-01-01

    We prove the local existence and uniqueness of week solution of the hyperbolic-parabolic Chemotaxis system with some nonlinear product terms. For one dimensional case, we prove also the global existence and uniqueness of the solution for the problem.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Wang; Yang, Helin, E-mail: emyang@mail.ccnu.edu.cn; Tian, Ying; Guo, Linyan [College of Physical Science and Technology, Central China Normal University, Wuhan 430079 (China); Huang, Xiaojun [College of Physical Science and Technology, Central China Normal University, Wuhan 430079 (China); College of physics and electrical engineering, Kashgar University, Kashgar, 844000 (China)

    2016-07-15

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

  18. On Doubly Degenerate Quasilinear Parabolic Equations of Higher Order

    Institute of Scientific and Technical Information of China (English)

    Zhen Hai LIU

    2005-01-01

    We deal with the existence of periodic solutions for doubly degenerate quasilinear parabolic equations of higher order, which can degenerate, on a part of the boundary, on a segment in the interior of the domain and in time.

  19. Homogenization of attractors for a class of nonlinear parabolic equations

    Institute of Scientific and Technical Information of China (English)

    WANG Guo-lian; ZHANG Xing-you

    2004-01-01

    The relation between the global attractors Aε for a calss of quasilinear parabolic equations and the global attractor A0for the homogenized equation is discussed, and an explicit error estimate between Aε and A0 is given.

  20. The homogenization of a class of degenerate quasilinear parabolic equations

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xingyou; HUANG Yong

    2003-01-01

    The homogenization of a class of degenerate quasilinear parabolic equations is studied. The Ap weight theory and the classical compensated compactness method are incorporated to obtain the homogenized equation.

  1. IDENTIFICATION OF PARAMETERS IN PARABOLIC EQUATIONS WITH NONLINEARITY

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper, we consider the identification of parameters in parabolic equations with nonlinearity. Some approximation processes for the identification problem are given. Our results improve and generalize the previous results.

  2. Classification of conformal representations induced from the maximal cuspidal parabolic

    Energy Technology Data Exchange (ETDEWEB)

    Dobrev, V. K., E-mail: dobrev@inrne.bas.bg [Scuola Internazionale Superiore di Studi Avanzati (Italy)

    2017-03-15

    In the present paper we continue the project of systematic construction of invariant differential operators on the example of representations of the conformal algebra induced from the maximal cuspidal parabolic.

  3. Differentiability at lateral boundary for fully nonlinear parabolic equations

    Science.gov (United States)

    Ma, Feiyao; Moreira, Diego R.; Wang, Lihe

    2017-09-01

    For fully nonlinear uniformly parabolic equations, the first derivatives regularity of viscosity solutions at lateral boundary is studied under new Dini type conditions for the boundary, which is called Reifenberg Dini conditions and is weaker than usual Dini conditions.

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

    Science.gov (United States)

    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.

  5. Quasiconformal mappings and degenerate elliptic and parabolic equations

    Directory of Open Access Journals (Sweden)

    Filippo Chiarenza

    1987-11-01

    Full Text Available In this paper two Harnak inequalities are proved concerning a degenerate elliptic and a degenerate parabolic equation. In both cases the weight giving the degeneracy is a power of the jacobian of a quasiconformal mapping.

  6. Flux form Semi-Lagrangian methods for parabolic problems

    Directory of Open Access Journals (Sweden)

    Bonaventura Luca

    2016-09-01

    Full Text Available A semi-Lagrangian method for parabolic problems is proposed, that extends previous work by the authors to achieve a fully conservative, flux-form discretization of linear and nonlinear diffusion equations. A basic consistency and stability analysis is proposed. Numerical examples validate the proposed method and display its potential for consistent semi-Lagrangian discretization of advection diffusion and nonlinear parabolic problems.

  7. MAXIMUM PRINCIPLES FOR SECOND-ORDER PARABOLIC EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    Antonio Vitolo

    2004-01-01

    This paper is the parabolic counterpart of previous ones about elliptic operators in unbounded domains. Maximum principles for second-order linear parabolic equations are established showing a variant of the ABP-Krylov-Tso estimate, based lower bound for super-solutions due to Krylov and Safonov. The results imply the uniqueness for the Cauchy-Dirichlet problem in a large class of infinite cylindrical and non-cylindrical domains.

  8. The parabolic trigonometric functions and the Chebyshev radicals

    OpenAIRE

    Dattoli, G.; Migliorati, M.; Ricci, P. E.

    2011-01-01

    The parabolic trigonometric functions have recently been introduced as an intermediate step between circular and hyperbolic functions. They have been shown to be expressible in terms of irrational functions, linked to the solution of third degree algebraic equations. We show the link of the parabolic trigonometric functions with the Chebyshev radicals and also prove that further generalized forms of trigonometric functions, providing the natural solutions of the quintic algebraic equation, ca...

  9. Comparison principle for parabolic equations in the Heisenberg group

    Directory of Open Access Journals (Sweden)

    Thomas Bieske

    2005-09-01

    Full Text Available We define two notions of viscosity solutions to parabolic equations in the Heisenberg group, depending on whether the test functions concern only the past or both the past and the future. We then exploit the Heisenberg geometry to prove a comparison principle for a class of parabolic equations and show the sufficiency of considering the test functions that concern only the past.

  10. Null controllability for a parabolic-elliptic coupled system

    CERN Document Server

    Fernández-Cara, E; de Menezes, S B

    2012-01-01

    In this paper, we prove the null controllability of some parabolic-elliptic systems. The control is distributed, locally supported in space and appears only in one PDE. The arguments rely on fixed-point reformulation and suitable Carleman estimates for the solutions to the adjoint system. Under appropriate assumptions, we also prove that the solution can be obtained as the asymptotic limit of some similar parabolic systems.

  11. Three-dimensional nonparaxial beams in parabolic rotational coordinates.

    Science.gov (United States)

    Deng, Dongmei; Gao, Yuanmei; Zhao, Juanying; Zhang, Peng; Chen, Zhigang

    2013-10-01

    We introduce a class of three-dimensional nonparaxial optical beams found in a parabolic rotational coordinate system. These beams, representing exact solutions of the nonparaxial Helmholtz equation, have inherent parabolic symmetries. Assisted with a computer-generated holography, we experimentally demonstrate the generation of different modes of these beams. The observed transverse beam patterns along the propagation direction agree well with those from our theoretical predication.

  12. Fabrication and characterization of non-linear parabolic microporous membranes.

    Science.gov (United States)

    Rajasekaran, Pradeep Ramiah; Sharifi, Payam; Wolff, Justin; Kohli, Punit

    2015-01-01

    Large scale fabrication of non-linear microporous membranes is of technological importance in many applications ranging from separation to microfluidics. However, their fabrication using traditional techniques is limited in scope. We report on fabrication and characterization of non-linear parabolic micropores (PMS) in polymer membranes by utilizing flow properties of fluids. The shape of the fabricated PMS corroborated well with simplified Navier-Stokes equation describing parabolic relationship of the form L - t(1/2). Here, L is a measure of the diameter of the fabricated micropores during flow time (t). The surface of PMS is smooth due to fluid surface tension at fluid-air interface. We demonstrate fabrication of PMS using curable polydimethylsiloxane (PDMS). The parabolic shape of micropores was a result of interplay between horizontal and vertical fluid movements due to capillary, viscoelastic, and gravitational forces. We also demonstrate fabrication of asymmetric "off-centered PMS" and an array of PMS membranes using this simple fabrication technique. PMS containing membranes with nanoscale dimensions are also possible by controlling the experimental conditions. The present method provides a simple, easy to adopt, and energy efficient way for fabricating non-linear parabolic shape pores at microscale. The prepared parabolic membranes may find applications in many areas including separation, parabolic optics, micro-nozzles / -valves / -pumps, and microfluidic and microelectronic delivery systems.

  13. Thermodynamics and the segmented compound parabolic concentrator

    Science.gov (United States)

    Widyolar, Bennett; Jiang, Lun; Winston, Roland

    2017-04-01

    Compound parabolic concentrator (CPC) reflector profiles are complex and can be difficult to manufacture using traditional methods. Computer numeric control machines, however, can approximate complex profiles by bending a series of small flat segments. We investigate the relationship between the number of segments and the optical transmission of a CPC approximated by equal length segments whose start and end points lie along the CPC profile. We also investigate a separate method for generating CPC-like profiles by adjusting the angle of each segment to satisfy the edge-ray principle. Three variations of this method are examined where the edge-ray condition is taken from the start, mid, and end points of each segment. A flux efficiency (FE) to compare concentrators, which combines the concentration ratio and optical efficiency, is introduced and directly relates to the maximum achievable flux on the absorber. We demonstrate that the FE defined is another way to look at the compromises one makes for a geometric concentrator designed under real-world constraints.

  14. Parabolic Trough Receiver Heat Loss Testing (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Price, H.; Netter, J.; Bingham, C.; Kutscher, C.; Burkholder, F.; Brandemuehl, M.

    2007-03-01

    Parabolic trough receivers, or heat collection elements (HCEs), absorb sunlight focused by the mirrors and transfer that thermal energy to a fluid flowing within them. Thje absorbing tube of these receivers typically operates around 400 C (752 F). HCE manufacturers prevent thermal loss from the absorbing tube to the environment by using sputtered selective Cermet coatings on the absorber and by surrounding the absorber with a glass-enclosed evacuated annulus. This work quantifies the heat loss of the Solel UVAC2 and Schott PTR70 HCEs. At 400 C, the HCEs perform similarly, losing about 400 W/m of HCE length. To put this in perspective, the incident beam radiation on a 5 m mirror aperture is about 4500 W/m, with about 75% of that energy ({approx} 3400 W/m) reaching the absorber surface. Of the 3400 W/m on the absorber, about 3000 W/m is absorbed into the working fluid while 400 W/m is lost to the environment.

  15. Parabolic Trough Solar Collector Initial Trials

    Directory of Open Access Journals (Sweden)

    Ghalya Pikra

    2012-03-01

    Full Text Available This paper discusses initial trials of parabolic trough solar collector (PTSC in Bandung. PTSC model consists of concentrator, absorber and tracking system. Concentrator designs are made with 2m aperture width, 6m length and 0.75m focal distance. The design is equipped with an automatic tracking system which is driven using 12V and 24Watt DC motor with 0.0125rpm rotational speed. Absorber/receiver is designed with evacuated tube type, with 1 inch core diameter and tube made of AISI304 and coated with black oxide, the outer tube is borosilicate glass with a 70 mm diameter and 1.5 m length. Working fluid stored in single type of thermal storage tank, a single phase with 37.7 liter volume. PTSC model testing carried out for 2 hours and 10 minutes produces heat output and input of 11.5 kW and 0.64 kW respectively. 

  16. Affective states and adaptation to parabolic flights

    Science.gov (United States)

    Collado, Aurélie; Langlet, Cécile; Tzanova, Tzvetomira; Hainaut, Jean-Philippe; Monfort, Vincent; Bolmont, Benoît

    2017-05-01

    This exploratory study investigates (i) inter-individual variations of affective states before a parabolic flight (i.e., PF) on the basis of quality of adaptation to physical demands, and (ii) intra-individual variations of affective states during a PF. Mood-states, state-anxiety and salivary cortisol were assessed in two groups with a different quality of adaptation (an Adaptive Group, i.e., AG, and a Maladaptive Group, i.e., MG) before and during a PF. Before PF, MG scored higher on mood states (Anger-Hostility, Fatigue-Inertia) than AG. During the flight, while AG seemed to present ;normal; affective responses to the demanding environment (e.g., increase in salivary cortisol), MG presented increases in mood states such as Confusion-Bewilderment or Tension-Anxiety. The findings suggest that the psychological states of MG could have disturbed their ability to integrate sensory information from an unusual environment, which led to difficulties in coping with the physical demands of PF.

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

    Science.gov (United States)

    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.

  18. It is Time for a Change:Petri Dishes Weaken Cells

    Institute of Scientific and Technical Information of China (English)

    Andrei P.Sommer; Mike Kh.Haddad; Hans-Joerg Fecht

    2012-01-01

    We wish to draw the attention to a potential deficiency in the biocompatibility of polystyrene cell culturc dishes which is caused by a softening of the material under relevant culture conditions.The finding confirms the central hypothesis of our previous model study.In it we assumed a local increase in pH at the interface between the hydrophilic polymer and liquid.The finding is of considerable biological interest.Polystyrene tissue culture dishes are now in use for 50 years.To the best of our knowledge their biocompatibility has never been challenged.Here we report the first experimental proof that exposure to water softens the surface of polystyrene Petri dishes.We expect that our results will stimulate the development ofa new generation of cell culture devices,including Petri dishes and culture flasks,and the establishment of improved biomimetic settings for tissuc engineering and stem cell research.New non-swelling biomaterials or nanocoatings designed to reduce the swelling of polymer culture dishes could improve cell performance.The need for further study is clear.

  19. Cultured articular chondrocytes sheets for partial thickness cartilage defects utilizing temperature-responsive culture dishes

    Directory of Open Access Journals (Sweden)

    N Kaneshiro

    2007-05-01

    Full Text Available The extracellular matrix (ECM of articular cartilage has several functions that are unique to joints. Although a technique for transplanting cultured chondrocytes has already been introduced, it is difficult to collect intact ECM when using enzymes to harvest samples. Temperature-responsive culture dishes have already been clinically applied in the fields of myocardial and corneal transplantation. Earlier studies have shown that a sheet of cultured cells with intact ECM and adhesive factors can be harvested using such culture dishes, which allow the surface properties of the dish to be reversibly altered by changing the temperature. Human chondrocytes were subjected to enzymatic digestion and then were seeded in temperature-responsive culture dishes. A sheet of chondrocytes was harvested by only reducing the temperature after the cultured cells reached confluency. A real-time PCR analysis of the chondrocyte sheets confirmed that type II collagen, aggrecan, and fibronectin were present. These results suggested that, although chondrocytes undergo dedifferentiation in a monolayer culture, multilayer chondrocyte sheets grown in a similar environment to that of three-dimensional culture may be able to maintain a normal phenotype. A histological examination suggested that multilayer chondrocyte sheets could thus prevent the loss of proteoglycans because the area covered by the sheets was well stained by safranin-O. The present experiments suggested that temperature-responsive culture dishes are useful for obtaining cultured chondrocytes, which may then be clinically employed as a substitute for periosteal patches because such sheets can be applied without a scaffold.

  20. Dorsal vertebral column abnormalities in dogs with disseminated idiopathic skeletal hyperostosis (DISH).

    Science.gov (United States)

    Decker, S De; Volk, H A

    2014-06-21

    Although disseminated idiopathic skeletal hyperostosis (DISH) most often affects the ventral aspect of the vertebral column, this study evaluated the occurrence, nature and clinical relevance of dorsal vertebral column abnormalities in 10 dogs with DISH for which CT or MRI and a complete neurological examination were available. Dorsal vertebral column abnormalities were present in eight dogs and included articular process hypertrophy (n=7 dogs), periarticular new bone formation (n=1), pseudoarthrosis between spinous processes (n=4) and thickening of the dorsal lamina (n=4). These dorsal vertebral abnormalities caused clinically relevant vertebral canal stenosis in six dogs and were the only cause of clinical signs in four of these dogs. Although the lumbosacral joint was not affected by DISH, these six dogs demonstrated lumbosacral vertebral canal stenosis and clinical signs of cauda equina compression, which included paraparesis (n=5 dogs), lumbosacral pain (n=4), urinary incontinence (n=4), faecal incontinence (n=1) and urinary and faecal incontinence (n=1). There is a possible association between DISH and hypertrophy of dorsal vertebral structures, potentially resulting in vertebral canal stenosis. Although these changes occurred at segments fused by DISH, they predominantly affected adjacent non-affected segments.

  1. Analysis and Design of a Dish/Stirling System for Solar Electric Generation with a 2.7 kW Air-Cooled Engine

    Directory of Open Access Journals (Sweden)

    Beltrán-Chacón R.

    2012-01-01

    Full Text Available This paper presents a mathematical modeling, simulation and design of a solar power system of a parabolic dish with an air-cooled Stirling engine of 2.7 kW. The model used for the solar concentrator, the cavity and the Stirling engine were successfully validated against experimental data. Based on a parametric study, the design of the components of the engine is carried out. The study shows that as system capacity increases, the overall efficiency is limited by the power required by the fan, since the design of the cooler needs greater amounts of heat removal by increasing the air flow without affecting the internal conditions of the process (mass flow of working gas and internal dimensions of the same. The system was optimized and achieves an overall efficiency of solar to electric energy conversion of 26.7%. This study shows that the use of an air-cooled Stirling engine is potentially attractive for power generation at low capacities.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. The Nonlinear Instability Modes of Dished Shallow Shells under Circular Line Loads

    Directory of Open Access Journals (Sweden)

    Liu Chang-Jiang

    2011-01-01

    Full Text Available This paper investigated the nonlinear stability problem of dished shallow shells under circular line loads. We derived the dimensionless governing differential equations of dished shallow shell under circular line loads according to the nonlinear theory of plates and shells and solved the governing differential equations by combing the free-parameter perturbation method (FPPM with spline function method (SFM to analyze the nonlinear instability modes of dished shallow shell under circular line loads. By analyzing the nonlinear instability modes and combining with concrete computational examples, we obtained the variation rules of the maximum deflection area of initial instability with different geometric parameters and loading action positions and discussed the relationship between the initial instability area and the maximum deflection area of initial instability. The results obtained from this paper provide some theoretical basis for engineering design and instability prediction and control of shallow-shell structures.

  4. Sky reconstruction from transit visibilities: PAON-4 and Tianlai Dish Array

    CERN Document Server

    Zhang, Jiao; Chen, Xuelei; Campagne, Jean-Eric; Magneville, Christophe; Wu, Fengquan

    2016-01-01

    The spherical harmonics $m$-mode decomposition is a powerful sky map reconstruction method suitable for radio interferometers operating in transit mode. It can be applied to various configurations, including dish arrays and cylinders. We describe the computation of the instrument response function, the point spread function (PSF), transfer function, the noise covariance matrix and noise power spectrum. The analysis in this paper is focused on dish arrays operating in transit mode. We show that arrays with regular spacing have more pronounced side lobes as well as structures in their noise power spectrum, compared to arrays with irregular spacing, specially in the north-south direction. A good knowledge of the noise power spectrum $C^{\\mathrm{noise}}(\\ell)$ is essential for intensity mapping experiments as non uniform $C^{\\mathrm{noise}}(\\ell)$ is a potential problem for the measurement of the HI power spectrum. Different configurations have been studied to optimise the PAON-4 and Tianlai dish array layouts. W...

  5. Performance Simulation Comparison for Parabolic Trough Solar Collectors in China

    Directory of Open Access Journals (Sweden)

    Jinping Wang

    2016-01-01

    Full Text Available Parabolic trough systems are the most used concentrated solar power technology. The operating performance and optical efficiency of the parabolic trough solar collectors (PTCs are different in different regions and different seasons. To determine the optimum design and operation of the parabolic trough solar collector throughout the year, an accurate estimation of the daily performance is needed. In this study, a mathematical model for the optical efficiency of the parabolic trough solar collector was established and three typical regions of solar thermal utilization in China were selected. The performance characteristics of cosine effect, shadowing effect, end loss effect, and optical efficiency were calculated and simulated during a whole year in these three areas by using the mathematical model. The simulation results show that the optical efficiency of PTCs changes from 0.4 to 0.8 in a whole year. The highest optical efficiency of PTCs is in June and the lowest is in December. The optical efficiency of PTCs is mainly influenced by the solar incidence angle. The model is validated by comparing the test results in parabolic trough power plant, with relative error range of 1% to about 5%.

  6. A Contribution for the Construction of Parabolic Mirrors

    CERN Document Server

    de Paula, L A N; Assis, A K T

    2008-01-01

    We present a new procedure for the construction of parabolic mirrors using low cost materials. We build a spinning system composed of nylon threads, fish hooks and a plastic bucket. We pour liquid plaster into the bucket and set it in constant rotational motion relative to the earth. A liquid substance assumes a parabolic profile when spinning at constant angular velocity relative to an inertial frame under the influence of an uniform vertical gravitational field. By keeping the bucket under rotation for a long time, the plaster solidifies into a parabolic format. We utilize this solidified plaster paraboloid as a model to construct a counter-mould of glass fibre and resin. Over this counter-mould it is placed stretched laminated foil and then it is poured thick plaster over it. In this way it is obtained a parabolic mirror made of laminated foil and plaster. Our only objective here is to present a new method for the construction of parabolic mirror using low cost materials. This allows further exploration of...

  7. Fabrication, Designing & Performance Analysis of Solar Parabolic Trough

    Directory of Open Access Journals (Sweden)

    Mayur G. Tayade,

    2014-07-01

    Full Text Available A parabolic trough solar collector uses a parabolic cylinder to reflect and concentrate sun radiations towards a receiver tube located at the focus line of the parabolic cylinder. The receiver absorbs the incoming radiations and transforms them into thermal energy, the latter being transported and collected by a fluid medium circulating within the receiver tube.This method of concentrated solar collection has the advantage of high efficiency and low cost, and can be used either for thermal energy collection, for generating electricity or for both, This paper focused on the fabrication and designing of solar parabolic trough, The designing of trough is depend upon the following parameters : Aperture of the concentrator , Inner diameter of absorber tube, Outer diameter of absorber tube, Inner diameter of glass tube, Outer diameter of glass tube, Length of parabolic trough, Concentration ratio, Collector aperture area, Specular reflectivity of concentrator, Glass cover transitivity for solar radiation, Absorber tube emissivity/emissivity, Intercept factor, Emissivity of absorber tube surface and Emissivity of glass. The performance analysis will be based on the Experimental data collection and calculations with reference to: Thermal performance calculations, Overall loss coefficient and heat correlations. Heat transfer coefficient on the inside surface of the absorber tube and Heat transfer coefficient between the absorber tube and the Cover.

  8. Internal jugular pressure increases during parabolic flight.

    Science.gov (United States)

    Martin, David S; Lee, Stuart M C; Matz, Timothy P; Westby, Christian M; Scott, Jessica M; Stenger, Michael B; Platts, Steven H

    2016-12-01

    One hypothesized contributor to vision changes experienced by >75% of International Space Station astronauts is elevated intracranial pressure (ICP). While no definitive data yet exist, elevated ICP might be secondary to the microgravity-induced cephalad fluid shift, resulting in venous congestion (overfilling and distension) and inhibition of cerebrospinal and lymphatic fluid drainage from the skull. The objective of this study was to measure internal jugular venous pressure (IJVP) during normo- and hypo-gravity as an index of venous congestion. IJVP was measured noninvasively using compression sonography at rest during end-expiration in 11 normal, healthy subjects (3 M, 8 F) during normal gravity (1G; supine) and weightlessness (0G; seated) produced by parabolic flight. IJVP also was measured in two subjects during parabolas approximating Lunar (1/6G) and Martian gravity (1/3G). Finally, IJVP was measured during increased intrathoracic pressure produced using controlled Valsalva maneuvers. IJVP was higher in 0G than 1G (23.9 ± 5.6 vs. 9.9 ± 5.1 mmHg, mean ± SD P < 0.001) in all subjects, and IJVP increased as gravity levels decreased in two subjects. Finally, IJVP was greater in 0G than 1G at all expiration pressures (P < 0.01). Taken together, these data suggest that IJVP is elevated during acute exposure to reduced gravity and may be elevated further by conditions that increase intrathoracic pressure, a strong modulator of central venous pressure and IJVP However, whether elevated IJVP, and perhaps consequent venous congestion, observed during acute microgravity exposure contribute to vision changes during long-duration spaceflight is yet to be determined. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  9. Molten salt parabolic trough system with synthetic oil preheating

    Science.gov (United States)

    Yuasa, Minoru; Hino, Koichi

    2017-06-01

    Molten salt parabolic trough system (MSPT), which can heat the heat transfer fluid (HTF) to 550 °C has a better performance than a synthetic oil parabolic trough system (SOPT), which can heat the HTF to 400 °C or less. The utilization of HTF at higher temperature in the parabolic trough system is able to realize the design of a smaller size of storage tank and higher heat to electricity conversion efficiency. However, with MSPT there is a great amount of heat loss at night so it is necessary to circulate the HTF at a high temperature of about 290 °C in order to prevent solidification. A new MSPT concept with SOPT preheating (MSSOPT) has been developed to reduce the heat loss at night. In this paper, the MSSOPT system, its performance by steady state analysis and annual performance analysis are introduced.

  10. Interaction Potential between Parabolic Rotator and an Outside Particle

    Directory of Open Access Journals (Sweden)

    Dan Wang

    2014-01-01

    Full Text Available At micro/nanoscale, the interaction potential between parabolic rotator and a particle located outside the rotator is studied on the basis of the negative exponential pair potential 1/Rn between particles. Similar to two-dimensional curved surfaces, we confirm that the potential of the three-dimensional parabolic rotator and outside particle can also be expressed as a unified form of curvatures; that is, it can be written as the function of curvatures. Furthermore, we verify that the driving forces acting on the particle may be induced by the highly curved micro/nano-parabolic rotator. Curvatures and the gradient of curvatures are the essential elements forming the driving forces. Through the idealized numerical experiments, the accuracy of the curvature-based potential is preliminarily proved.

  11. Decomposition method for solving parabolic equations in finite domains

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This paper presents a comparison among Adomian decomposition method (ADM), Wavelet-Galerkin method (WGM),the fully explicit (1,7) finite difference technique (FTCS), the fully implicit (7,1) finite difference method (BTCS), (7,7)Crank-Nicholson type finite difference formula (C-N), the fully explicit method (1,13) and 9-point finite difference method, for solving parabolic differential equations with arbitrary boundary conditions and based on weak form functionals in finite domains.The problem is solved rapidly, easily and elegantly by ADM. The numerical results on a 2D transient heat conducting problem and 3D diffusion problem are used to validate the proposed ADM as an effective numerical method for solving finite domain parabolic equations. The numerical results showed that our present method is less time consuming and is easier to use than other methods. In addition, we prove the convergence of this method when it is applied to the nonlinear parabolic equation.

  12. Graphene Nanoribbon Conductance Model in Parabolic Band Structure

    Directory of Open Access Journals (Sweden)

    Mohammad Taghi Ahmadi

    2010-01-01

    Full Text Available Many experimental measurements have been done on GNR conductance. In this paper, analytical model of GNR conductance is presented. Moreover, comparison with published data which illustrates good agreement between them is studied. Conductance of GNR as a one-dimensional device channel with parabolic band structures near the charge neutrality point is improved. Based on quantum confinement effect, the conductance of GNR in parabolic part of the band structure, also the temperature-dependent conductance which displays minimum conductance near the charge neutrality point are calculated. Graphene nanoribbon (GNR with parabolic band structure near the minimum band energy terminates Fermi-Dirac integral base method on band structure study. While band structure is parabola, semiconducting GNRs conductance is a function of Fermi-Dirac integral which is based on Maxwell approximation in nondegenerate limit especially for a long channel.

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

    Science.gov (United States)

    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.

  14. In-plane elastic stability of fixed parabolic shallow arches

    Institute of Scientific and Technical Information of China (English)

    CAI JianGuo; FENG Jian; CHEN Yao; HUANG LiFeng

    2009-01-01

    The nonlinear behavior of fixed parabolic shallow arches subjected to a vertical uniform load is inves-tigated to evaluate the in-plane buckling load. The virtual work principle method is used to establish the non-linear equilibrium and buckling equations. Analytical solutions for the non-linear in-plane sym-metric snap-through and antisymmetric bifurcation buckling loads are obtained. Based on the least square method, an approximation for the symmetric buckling load of fixed parabolic arch is proposedto simplify the solution process. And the relation between modified slenderness and buckling modes are discussed. Comparisons with the results of finite element analysis demonstrate that the solutions are accurate. A cable-arch structure is presented to improve the in-plane stability of parabolic arches. The comparison of buckling loads between cable-arch systems and arches only show that the effect of cables becomes more evident with the increase of arch's modified slenderness.

  15. In-plane elastic stability of fixed parabolic shallow arches

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The nonlinear behavior of fixed parabolic shallow arches subjected to a vertical uniform load is inves- tigated to evaluate the in-plane buckling load. The virtual work principle method is used to establish the non-linear equilibrium and buckling equations. Analytical solutions for the non-linear in-plane sym- metric snap-through and antisymmetric bifurcation buckling loads are obtained. Based on the least square method, an approximation for the symmetric buckling load of fixed parabolic arch is proposed to simplify the solution process. And the relation between modified slenderness and buckling modes are discussed. Comparisons with the results of finite element analysis demonstrate that the solutions are accurate. A cable-arch structure is presented to improve the in-plane stability of parabolic arches. The comparison of buckling loads between cable-arch systems and arches only show that the effect of cables becomes more evident with the increase of arch’s modified slenderness.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2017-06-01

    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.

  18. Real Parabolic Vector Bundles over a Real Curve

    Indian Academy of Sciences (India)

    Sanjay Amrutiya

    2014-02-01

    We define real parabolic structures on real vector bundles over a real curve. Let $(X, _X)$ be a real curve, and let $S\\subset X$ be a non-empty finite subset of such that $_X(S) = S$. Let ≥ 2 be an integer. We construct an -fold cyclic cover : $Y→ X$ in the category of real curves, ramified precisely over each point of , and with the property that for any element of the Galois group , and any $y\\in Y$, one has $_Y(gy) = g^{-1}_Y(y)$. We established an equivalence between the category of real parabolic vector bundles on $(X,_X)$ with real parabolic structure over , all of whose weights are integral multiples of 1/, and the category of real -equivariant vector bundles on $(Y, _Y)$.

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    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.

  20. 9 CFR 381.167 - Other poultry dishes and specialty items.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Other poultry dishes and specialty..., DEPARTMENT OF AGRICULTURE AGENCY ORGANIZATION AND TERMINOLOGY; MANDATORY MEAT AND POULTRY PRODUCTS INSPECTION AND VOLUNTARY INSPECTION AND CERTIFICATION POULTRY PRODUCTS INSPECTION REGULATIONS Definitions...

  1. A small scale cell culture system to analyze mechanobiology using reporter gene constructs and polyurethane dishes

    DEFF Research Database (Denmark)

    Seefried, Lothar; Mueller-Deubert, Sigrid; Wentzer, Thomas Schwarz

    2010-01-01

    of mechanotransduction and its crosstalk with biochemically induced signal transduction, AP1 and SP1 luciferase reporter gene constructs were cloned and transfected into various cell lines and primary cells. A newly developed bioreactor and small-scale 24-well polyurethane dishes were used to apply cyclic stretching...

  2. THE MICROGARDENING COOKBOOK, DIRECTIONS FOR PREPARING DISHES AND TUBES OF STERILE NUTRIENT AGAR.

    Science.gov (United States)

    CHANDLER, MARION N.

    THIS BOOKLET WAS PREPARED FOR TEACHER USE IN ASSOCIATION WITH THE ELEMENTARY SCIENCE STUDY UNIT "MICROGARDENING." IT CONTAINS DIRECTIONS FOR PREPARING CULTURE DISHES AND TUBES OF NUTRIENT STERILE AGAR FOR FUNGAL AND/OR BACTERIAL GROWTH. IT INCLUDES (1) LISTS OF NEEDED SUPPLIES AND EQUIPMENT, (2) DIRECTIONS FOR THE PREPARATION AND…

  3. Stamped Petri dishes for 3D cell culture and drug testing

    NARCIS (Netherlands)

    Sridhar, Adithya; de Boer, Hans L.; van den Berg, Albert; le Gac, Severine

    2013-01-01

    We report here an experimentation platform directly made in a commercially available Petri dish for large-scale production of uniformly sized microtissues and their in situ characterization using both conventional microscopy and a scanning probe technique. The platform is realized by hot embossing m

  4. THE MICROGARDENING COOKBOOK, DIRECTIONS FOR PREPARING DISHES AND TUBES OF STERILE NUTRIENT AGAR.

    Science.gov (United States)

    CHANDLER, MARION N.

    THIS BOOKLET WAS PREPARED FOR TEACHER USE IN ASSOCIATION WITH THE ELEMENTARY SCIENCE STUDY UNIT "MICROGARDENING." IT CONTAINS DIRECTIONS FOR PREPARING CULTURE DISHES AND TUBES OF NUTRIENT STERILE AGAR FOR FUNGAL AND/OR BACTERIAL GROWTH. IT INCLUDES (1) LISTS OF NEEDED SUPPLIES AND EQUIPMENT, (2) DIRECTIONS FOR THE PREPARATION AND…

  5. Modelling dishes and exploring culinary 'precisions': the two issues of molecular gastronomy.

    Science.gov (United States)

    This, Hervé

    2005-04-01

    The scientific strategy of molecular gastronomy includes modelling 'culinary definitions' and experimental explorations of 'culinary precisions'. A formalism that describes complex dispersed systems leads to a physical classification of classical sauces, as well as to the invention of an infinite number of new dishes.

  6. Mobile Satellite Reception with a Virtual Satellite Dish based on a Reconfigurable Multi-Processor Architecture

    NARCIS (Netherlands)

    Burgwal, van de M.D.; Rovers, K.C.; Blom, K.C.H.; Kokkeler, A.B.J.; Smit, G.J.M.

    2011-01-01

    Traditionally, mechanically steered dishes or analog phased array beamforming systems have been used for radio frequency receivers, where strong directivity and high performance were much more important than low-cost requirements. Real-time controlled digital phased array beamforming could not be re

  7. Membrane dish analysis: A summary of structural and optical analysis capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Steele, C.R.; Balch, C.D.; Jorgensen, G.J.; Wendelin, T.; Lewandowski, A.

    1991-11-01

    Research at SERI within the Department of Energy's Solar Thermal Technology Program has focused on the development of membrane dish concentrators for space and terrestrial power applications. As potentially lightweight, inexpensive, high-performance structures, they are excellent candidates for space-deployable energy sources as well as cost-effective terrestrial energy concepts. A thorough engineering research treatment of these types of structures consists primarily of two parts: (1) structural mechanics of the membrane and ring support and (2) analysis and characterization of the concentrator optical performance. It is important to understand the effects of the membrane's structure and support system on the optical performance of the concentrator. This requires an interface between appropriate structural and optical models. Until recently, such models and the required interface have not existed. This report documents research that has been conducted at SERI in this area. It is a compilation of several papers describing structural models of membrane dish structures and optical models used to predict dish concentrator optical and thermal performance. The structural models were developed under SERI subcontract by Dr. Steele and Dr. Balch of Stanford University. The optical model was developed in-house by SERI staff. In addition, the interface between the models is described. It allows easy and thorough characterization of membrane dish systems from the mechanics to the resulting optical performance. The models described herein have been and continue to be extremely useful to SERI, industry, and universities involved with the modeling and analysis of lightweight membrane concentrators for solar thermal applications.

  8. Regularity for solutions of non local parabolic equations

    CERN Document Server

    Lara, Héctor A Chang

    2011-01-01

    We study the regularity of solutions of parabolic fully nonlinear nonlocal equations. We proof $C^\\a$ regularity in space and time and for translation invariant equations and under different assumptions on the kernels $C^{1,\\a}$ in space and time regularity. The proofs rely on a weak parabolic ABP inspired in recent work done by L. Silvestre and the classic ideas of K. Tso and L. Wang. Our results remain uniform as $\\s\\to2$ allowing us to understand the non local theory as an extension to the classical one.

  9. NEW ALTERNATING DIRECTION FINITE ELEMENT SCHEME FOR NONLINEAR PARABOLIC EQUATION

    Institute of Scientific and Technical Information of China (English)

    崔霞

    2002-01-01

    A new alternating direction (AD) finite element (FE) scheme for 3-dimensional nonlinear parabolic equation and parabolic integro-differential equation is studied. By using AD,the 3-dimensional problem is reduced to a family of single space variable problems, calculation work is simplified; by using FE, high accuracy is kept; by using various techniques for priori estimate for differential equations such as inductive hypothesis reasoning, the difficulty arising from the nonlinearity is treated. For both FE and ADFE schemes, the convergence properties are rigorously demonstrated, the optimal H1- and L2-norm space estimates and the O((△t)2) estimate for time variable are obtained.

  10. Focusing of Intense Laser via Parabolic Plasma Concave Surface

    Science.gov (United States)

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

    2015-12-01

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

  11. General difference schemes with intrinsic parallelism for nonlinear parabolic systems

    Institute of Scientific and Technical Information of China (English)

    周毓麟; 袁光伟

    1997-01-01

    The boundary value problem for nonlinear parabolic system is solved by the finite difference method with intrinsic parallelism. The existence of the discrete vector solution for the general finite difference schemes with intrinsic parallelism is proved by the fixed-point technique in finite-dimensional Euclidean space. The convergence and stability theorems of the discrete vector solutions of the nonlinear difference system with intrinsic parallelism are proved. The limitation vector function is just the unique generalized solution of the original problem for the parabolic system.

  12. Nonlinear Parabolic Equations with Singularities in Colombeau Vector Spaces

    Institute of Scientific and Technical Information of China (English)

    Mirjana STOJANOVI(C)

    2006-01-01

    We consider nonlinear parabolic equations with nonlinear non-Lipschitz's term and singular initial data like Dirac measure, its derivatives and powers. We prove existence-uniqueness theorems in Colombeau vector space gC1,w2,2([O,T),Rn),n ≤ 3. Due to high singularity in a case of parabolic equation with nonlinear conservative term we employ the regularized derivative for the conservative term, in order to obtain the global existence-uniqueness result in Colombeau vector space gC1,L2([O,T),Rn),n ≤ 3.

  13. Some remarks on singular solutions of nonlinear elliptic equations. III: viscosity solutions, including parabolic operators

    CERN Document Server

    Caffarelli, Luis; Nirenberg, Louis

    2011-01-01

    The paper concerns singular solutions of nonlinear elliptic equations, which include removable singularities for viscosity solutions, a strengthening of the Hopf Lemma including parabolic equations, Strong maximum principle and Hopf Lemma for viscosity solutions including also parabolic equations.

  14. Well-posedness of nonlocal parabolic differential problems with dependent operators.

    Science.gov (United States)

    Ashyralyev, Allaberen; Hanalyev, Asker

    2014-01-01

    The nonlocal boundary value problem for the parabolic differential equation v'(t) + A(t)v(t) = f(t) (0 ≤ t ≤ T), v(0) = v(λ) + φ, 0 parabolic equations with dependent coefficients are established.

  15. On the regularity of optimal control for a parabolic system of order 2m

    Directory of Open Access Journals (Sweden)

    Ornella Fiodo

    1992-05-01

    Full Text Available An optimal control problem for a parabolic operator of order 2m with the boundary conditions containing the control is considered. A regularity theorem for the parabolic problem and the regularity of the optimal control is proved.

  16. Nutritional assessment of the most frequently consumed dishes in a slum in Iquitos, Peruvian Amazon

    Directory of Open Access Journals (Sweden)

    Guillermo Molina Recio

    Full Text Available Introduction: Large nutritional surveys in Peru have identified the magnitude and location of the different types of malnutrition. The chronic type is the most prevalent one. However, although rates may be considered as alarming (even more in rural areas, only one of these studies contains information about intake characteristics, using 24-hour recalls (R24. That is, it lacks some other systems, adapted to the gastronomical characteristics of their regions and to the bioavailability of food in each area, in order to locate the origin of this situation and, thus, propose truly effective and efficient solutions. Aim: To determine the nutritional value of the main dishes consumed by the residents of a slum in Peruvian Amazon. Methods: Ninety-eight participants completed three 24-h recalls. Based on these data, we selected the 25 most commonly eaten dishes and evaluated their nutritional composition. We took note of the homemade recipes, weights and measures. In addition, we observed preparation and cooking. The mean nutritional composition of each dish was calculated per 100 g using the Nutriplato 4.6. software. We also calculated gains or losses resulting from culinary treatments. Results: Within those which include milk, the highest energy density is the mingado de arroz. In the group of fish, the most energetic is pescado frito, while within meat-based recipes tallarín con pollo, res asada and chancho frito are the most energetic ones. Regarding prepared dishes, the juane is the highest energy density of all recipes. Inside garnish, using bananas as the main ingredient, plátano frito and madurito are the most energetic. Fats are higher in fried dishes and those which contribute most fat ratio. The same thing happens with garnish as 100 grams of plátano frito or madurito contain more than 70% of the RDA. Res asada and juane present the highest sodium level. Conclusions: If we wish to offer healthier dishes, it is necessary to change their

  17. Ray analysis of a class of hybrid cylindrical aircraft wings

    OpenAIRE

    Jha, RM; Bokhari, SA; Sudhakan, V; Mahapatra, PR

    1988-01-01

    A new approach to the modelling of aircraft wings, based on the combination of hybrid quadric (parabolic and circular) cylinders, has been presented for electromagnetic applications. Closed-form expressions have been obtained for ray parameters required in the high-frequency mutual coupling computation of antenna pairs located arbitrarily on an aircraft wing.

  18. Ka-Band Parabolic Deployable Antenna (KaPDA) Enabling High Speed Data Communication for CubeSats

    Science.gov (United States)

    Sauder, Jonathan F.; Chahat, Nacer; Hodges, Richard; Thomson, Mark W.; Rahmat-Samii, Yahya

    2015-01-01

    CubeSats are at a very exciting point as their mission capabilities and launch opportunities are increasing. But as instruments become more advanced and operational distances between CubeSats and earth increase communication data rate becomes a mission-limiting factor. Improving data rate has become critical enough for NASA to sponsor the Cube Quest Centennial Challenge when: one of the key metrics is transmitting as much data as possible from the moon and beyond Currently, many CubeSats communicate on UHF bands and those that have high data rate abilities use S-band or X-band patch antennas. The CubeSat Aneas, which was launched in September 2012, pushed the envelope with a half-meter S-band dish which could achieve 100x the data rate of patch antennas. A half-meter parabolic antenna operating at Ka-band would increase data rates by over 100x that of the AMOS antenM and 10,000 that of X-band patch antennas.

  19. A parabolic singular perturbation problem with an internal layer

    NARCIS (Netherlands)

    Grasman, J.; Shih, S.D.

    2004-01-01

    A method is presented to approximate with singular perturbation methods a parabolic differential equation for the quarter plane with a discontinuity at the corner. This discontinuity gives rise to an internal layer. It is necessary to match the local solution in this layer with the one in a corner l

  20. Long-term average performance benefits of parabolic trough improvements

    Energy Technology Data Exchange (ETDEWEB)

    Gee, R.; Gaul, H.W.; Kearney, D.; Rabl, A.

    1980-03-01

    Improved parabolic trough concentrating collectors will result from better design, improved fabrication techniques, and the development and utilization of improved materials. The difficulty of achieving these improvements varies as does their potential for increasing parabolic trough performance. The purpose of this analysis is to quantify the relative merit of various technology advancements in improving the long-term average performance of parabolic trough concentrating collectors. The performance benefits of improvements are determined as a function of operating temperature for north-south, east-west, and polar mounted parabolic troughs. The results are presented graphically to allow a quick determination of the performance merits of particular improvements. Substantial annual energy gains are shown to be attainable. Of the improvements evaluated, the development of stable back-silvered glass reflective surfaces offers the largest performance gain for operating temperatures below 150/sup 0/C. Above 150/sup 0/C, the development of trough receivers that can maintain a vacuum is the most significant potential improvement. The reduction of concentrator slope errors also has a substantial performance benefit at high operating temperatures.

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

    Science.gov (United States)

    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.

  2. Viscosity solutions of fully nonlinear functional parabolic PDE

    Directory of Open Access Journals (Sweden)

    Liu Wei-an

    2005-01-01

    Full Text Available By the technique of coupled solutions, the notion of viscosity solutions is extended to fully nonlinear retarded parabolic equations. Such equations involve many models arising from optimal control theory, economy and finance, biology, and so forth. The comparison principle is shown. Then the existence and uniqueness are established by the fixed point theory.

  3. Almost periodic solutions to systems of parabolic equations

    Directory of Open Access Journals (Sweden)

    Janpou Nee

    1994-01-01

    Full Text Available In this paper we show that the second-order differential solution is 2-almost periodic, provided it is 2-bounded, and the growth of the components of a non-linear function of a system of parabolic equation is bounded by any pair of con-secutive eigenvalues of the associated Dirichlet boundary value problems.

  4. Improved Green's function parabolic equation method for atmospheric sound propagation

    NARCIS (Netherlands)

    Salomons, E.M.

    1998-01-01

    The numerical implementation of the Green's function parabolic equation (GFPE) method for atmospheric sound propagation is discussed. Four types of numerical errors are distinguished: (i) errors in the forward Fourier transform; (ii) errors in the inverse Fourier transform; (iii) errors in the refra

  5. Stability test for a parabolic partial differential equation

    NARCIS (Netherlands)

    Vajta, Miklos

    2001-01-01

    The paper describes a stability test applied to coupled parabolic partial differential equations. The PDE's describe the temperature distribution of composite structures with linear inner heat sources. The distributed transfer functions are developed based on the transmission matrix of each layer.

  6. Nyquist stability test for a parabolic partial differential equation

    NARCIS (Netherlands)

    Vajta, Miklos; Hamza, M.H.

    2000-01-01

    The paper describes a Nyquist stability test applied to a parabolic partial differential equation. The PDE describes the temperature distribution of composite structures with linear inner heat source. The distributed transfer functions have been developed by the transmission matrix method. To

  7. The ellipse in parabolic motion: An undergraduate experiment

    Science.gov (United States)

    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.

  8. On some perturbation techniques for quasi-linear parabolic equations

    Directory of Open Access Journals (Sweden)

    Igor Malyshev

    1990-01-01

    Full Text Available We study a nonhomogeneous quasi-linear parabolic equation and introduce a method that allows us to find the solution of a nonlinear boundary value problem in “explicit” form. This task is accomplished by perturbing the original equation with a source function, which is then found as a solution of some nonlinear operator equation.

  9. MULTIGRID FOR THE MORTAR FINITE ELEMENT FOR PARABOLIC PROBLEM

    Institute of Scientific and Technical Information of China (English)

    Xue-jun Xu; Jin-ru Chen

    2003-01-01

    In this paper, a mortar finite element method for parabolic problem is presented. Multigrid method is used for solving the resulting discrete system. It is shown that the multigrid method is optimal, I.e, the convergence rate is independent of the mesh size L and the time step parameter т.

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

    Science.gov (United States)

    Lasiecka, I.

    1980-01-01

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

  11. Parabolic vortex equations and instantons of infinite energy

    Science.gov (United States)

    Biquard, Olivier; García-Prada, Oscar

    1997-02-01

    We study the vortex equations on parabolic bundles over a Riemann surface and prove a Hitchin-Kobayashi-type correspondence relating the existence of solutions to a certain stability condition. This is achieved by translating our problem into a four-dimensional one, via dimensional reduction arguments. In return we obtain examples of instantons of infinite energy.

  12. Negative Trions Trapped by a Spherical Parabolic Quantum Dot

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, a negatively charged exciton trapped by a spherical parabolic quantum dot has been investigated. The energy spectra of low-lying states are calculated by means of matrix diagonalization. The important feature of the low-lying states of the negatively charged excitons in a spherical quantum dot is obtained via an analysis of the energy spectra.

  13. On an algorithm for solving parabolic and elliptic equations

    Science.gov (United States)

    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.

  14. Compactness of the commutators of parabolic singular integrals

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper,the authors prove that the commutator [b,T] of the parabolic singular integrals is a compact operator on Lp(Rn)(1 < p < ∞) if and only if b ∈ VMO(Rn,ρ).The result is substantial improvement and extension of some known results.

  15. Null controllability for a fourth order parabolic equation

    Institute of Scientific and Technical Information of China (English)

    YU Hang

    2009-01-01

    In the paper,the null interior controllability for a fourth order parabolic equation is obtained.The method Is based on Lebeau-Rabbiano inequality which is a quantitative unique continuation property for the sum of eigenfunctions of the Laplacian.

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

    Science.gov (United States)

    Karmali, Faisal; Shelhamer, Mark

    2008-09-01

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

  17. The fundamental solutions for fractional evolution equations of parabolic type

    Directory of Open Access Journals (Sweden)

    Mahmoud M. El-Borai

    2004-01-01

    Full Text Available The fundamental solutions for linear fractional evolution equations are obtained. The coefficients of these equations are a family of linear closed operators in the Banach space. Also, the continuous dependence of solutions on the initial conditions is studied. A mixed problem of general parabolic partial differential equations with fractional order is given as an application.

  18. Numerical and asymptotic aspects of parabolic cylinder functions

    NARCIS (Netherlands)

    Temme, N.M.

    2000-01-01

    Several uniform asymptotics expansions of the Weber parabolic cylinder functions are considered, one group in terms of elementary functions, another group in terms of Airy functions. Starting point for the discussion are asymptotic expansions given earlier by F.W.J. Olver. Some of his results are

  19. Integral representations for computing real parabolic cylinder functions

    NARCIS (Netherlands)

    Gil, A.; Segura, J.; Temme, N.M.

    2005-01-01

    Integral representations are derived for the parabolic cylinder functions U(a,x), V(a,x) and W(a,x) and their derivatives. The new integrals will be used in numerical algorithms based on quadrature. They follow from contour integrals in the complex plane, by using methods from asymptotic analysis (s

  20. SOLVING ∂¯b ON PARABOLIC LAMINATIONS

    Institute of Scientific and Technical Information of China (English)

    王刚

    2014-01-01

    Let X be a compact set which is laminated by parabolic Riemiann surfaces. For the CR positive line bundle L, there exists an integer N ∈ N such that for any s > N and any continuous v∈V(0,1) X N LN s, there exists a continuous u∈LN s solving ∂¯bu=v.

  1. Parabolic stable Higgs bundles over complete noncompact Riemann surfaces

    Institute of Scientific and Technical Information of China (English)

    李嘉禹; 王友德

    1999-01-01

    Let M be an open Riemann surface with a finite set of punctures, a complete Poincar(?)-like metric is introduced near the punctures and the equivalence between the stability of an indecomposable parabolic Higgs bundle, and the existence of a Hermitian-Einstein metric on the bundle is established.

  2. Polarization properties of linearly polarized parabolic scaling Bessel beams

    Science.gov (United States)

    Guo, Mengwen; Zhao, Daomu

    2016-10-01

    The intensity profiles for the dominant polarization, cross polarization, and longitudinal components of modified parabolic scaling Bessel beams with linear polarization are investigated theoretically. The transverse intensity distributions of the three electric components are intimately connected to the topological charge. In particular, the intensity patterns of the cross polarization and longitudinal components near the apodization plane reflect the sign of the topological charge.

  3. An Application of Calculus: Optimum Parabolic Path Problem

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    Nix, S; Imai, Y; Ishikawa, T

    2016-07-26

    Red blood cells migrate to the center of the blood vessel in a process called axial migration, while other blood cells, such as white blood cells and platelets, are disproportionately found near the blood vessel wall. However, much is still unknown concerning the lateral migration of cells in the blood; the specific effect of hydrodynamic factors such as a wall or a shear gradient is still unclear. In this study, we investigate the lateral migration of a capsule using the boundary integral method, in order to compute exactly an infinite computational domain for an unbounded parabolic flow and a semi-infinite computational domain for a near-wall parabolic flow in the limit of Stokes flow. We show that the capsule lift velocity in an unbounded parabolic flow is linear with respect to the shear gradient, while the lift velocity in a near-wall parabolic flow is dependent on the distance to the wall. Then, using these relations, we give an estimation of the relative effect of the shear gradient as a function of channel width and distance between the capsule and the wall. This estimation can be used to determine cases in which the effect of the shear gradient or wall can be neglected; for example, the formation of the cell-free layer in blood vessels is determined to be unaffected by the magnitude of the shear gradient. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. An Application of Calculus: Optimum Parabolic Path Problem

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Karmali, Faisal; Shelhamer, Mark

    2008-01-01

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

  8. Compound parabolic concentrator with cavity for tubular absorbers

    Science.gov (United States)

    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).

  9. Nonlinear Hyperbolic-Parabolic System Modeling Some Biological Phenomena

    Institute of Scientific and Technical Information of China (English)

    WU Shaohua; CHEN Hua

    2011-01-01

    In this paper, we study a nonlinear hyperbolic-parabolic system modeling some biological phenomena. By semigroup theory and Leray-Schauder fixed point argument, the local existence and uniqueness of the weak solutions for this system are proved. For the spatial dimension N = 1, the global existence of the weak solution will be established by the bootstrap argument.

  10. Anisotropic uniqueness classes for a degenerate parabolic equation

    Energy Technology Data Exchange (ETDEWEB)

    Vil' danova, V F [Bashkir State Pedagogical University, Ufa (Russian Federation); Mukminov, F Kh [Bashkir State University, Ufa (Russian Federation)

    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. Electromagnetic Casimir Forces of Parabolic Cylinder and Knife-Edge Geometries

    CERN Document Server

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

    2011-01-01

    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.

  12. Cultivation-independent comprehensive investigations on bacterial communities in serofluid dish, a traditional Chinese fermented food.

    Science.gov (United States)

    Chen, Peng; Wu, Zhengrong; Zhao, Yang; Wei, Yan; Xu, Ruixiang; Yan, Lei; Li, Hongyu

    2016-03-01

    Serofluid dish (or Jiangshui, in Chinese), a traditional food in the Chinese culture, is made from vegetables by fermentation. In this study, bacterial community of the fermented serofluid dish was assessed by Illumina amplicon sequencing. The metagenome comprised of 49,589 average raw reads with an average 11,497,917 bp and G + C content is 52.46%. This is the first report on V4 hyper-variable region of the 16S rRNA metagenome sequence employing Illumina platform to profile the microbial community of this little known fermented food from Gansu Province, China. The metagenome sequence can be accessed at NCBI, SRA database accession no. SRP065370.

  13. Cultivation-independent comprehensive investigations on bacterial communities in serofluid dish, a traditional Chinese fermented food

    Directory of Open Access Journals (Sweden)

    Peng Chen

    2016-03-01

    Full Text Available Serofluid dish (or Jiangshui, in Chinese, a traditional food in the Chinese culture, is made from vegetables by fermentation. In this study, bacterial community of the fermented serofluid dish was assessed by Illumina amplicon sequencing. The metagenome comprised of 49,589 average raw reads with an average 11,497,917 bp and G+C content is 52.46%. This is the first report on V4 hyper-variable region of the 16S rRNA metagenome sequence employing Illumina platform to profile the microbial community of this little known fermented food from Gansu Province, China. The metagenome sequence can be accessed at NCBI, SRA database accession no. SRP065370.

  14. Acrylamide in a fried potato dish (rösti) from restaurants in Zurich, Switzerland.

    Science.gov (United States)

    McCombie, Gregor; Biedermann, Maurus; Biedermann-Brem, Sandra; Suter, Gaby; Eicher, Angela; Pfefferle, Anton

    2016-01-01

    Rösti, a fried potato product, is a large contributor to acrylamide exposure locally in Switzerland. A survey of 55 dishes prepared by 51 restaurants in the city of Zurich showed that the average rösti contained 702 µg/kg acrylamide. By analysing the content of reducing sugars in the potatoes used for frying, it is shown that with simple measures, the exposure to acrylamide could easily be reduced by factor 2 or more, while even improving the culinary experience. Though rösti is a typical dish in the German-speaking areas in Switzerland, the result may be of general interest for fried potato products which are popular in large areas of Central Europe.

  15. Dish washing detergent market%中国洗洁精市场概况

    Institute of Scientific and Technical Information of China (English)

    谷俊

    2011-01-01

    this paper points out the phenomenon of concentration highly and homogeneity seriously in dish washing detergent market,analyzes factors in the main sale channels,approach as well as influence for consumers purchase.Finally,it introduces the strategy in dish washing detergent market.%探讨了洗洁精市场集中度高和同质化严重的现象。分析了主要销售渠道、销售手段以及影响消费者购买洗洁精的因素。最后,介绍了洗洁精行业的市场竞争战略。

  16. Membrane dish analysis: A summary of structural and optical analysis capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Steele, C.R.; Balch, C.D.; Jorgensen, G.J.; Wendelin, T.; Lewandowski, A.

    1991-11-01

    Research at SERI within the Department of Energy`s Solar Thermal Technology Program has focused on the development of membrane dish concentrators for space and terrestrial power applications. As potentially lightweight, inexpensive, high-performance structures, they are excellent candidates for space-deployable energy sources as well as cost-effective terrestrial energy concepts. A thorough engineering research treatment of these types of structures consists primarily of two parts: (1) structural mechanics of the membrane and ring support and (2) analysis and characterization of the concentrator optical performance. It is important to understand the effects of the membrane`s structure and support system on the optical performance of the concentrator. This requires an interface between appropriate structural and optical models. Until recently, such models and the required interface have not existed. This report documents research that has been conducted at SERI in this area. It is a compilation of several papers describing structural models of membrane dish structures and optical models used to predict dish concentrator optical and thermal performance. The structural models were developed under SERI subcontract by Dr. Steele and Dr. Balch of Stanford University. The optical model was developed in-house by SERI staff. In addition, the interface between the models is described. It allows easy and thorough characterization of membrane dish systems from the mechanics to the resulting optical performance. The models described herein have been and continue to be extremely useful to SERI, industry, and universities involved with the modeling and analysis of lightweight membrane concentrators for solar thermal applications.

  17. AIPS++ and the GBT: a layered approach to processing and analysis of single-dish data

    Science.gov (United States)

    Braatz, James; McMullin, Joseph; Garwood, Robert; Kemball, Athol

    2002-12-01

    The Green Bank Telescope (GBT) is a new 100-m diameter antenna with an unblocked aperture and an active surface. It is designed to observe at frequencies from 300 MHz to 100 GHz, and includes state of the art continuum and spectral backends. The GBT is also capable of pulsar work and recording as a VLB station, and array receivers are being developed as well. AIPS++ is the integral software package for analysis of GBT data both for scientific analysis as well as for control and engineering analysis of the component systems. In this paper we will give an overview of how the AIPS++ system is used with the GBT, with special consideration to the development of spectral analysis software. AIPS++ allows a layered approach to software development, and the spectral analysis capability gives a strong example of the usefulness of the layered approach. At the heart of AIPS++ is a suite of tools which are capable of astronomy-specific calculations as well as general purpose mathematical analysis, data visualization, GUI development, and scripting. A tool for analyzing single-dish data, DISH, is developed on this platform. DISH includes a number of modern features such as bulk processing of datasets and versatile GUI interaction. A simplified package using a familiar CLI, known as UNI-jr, is built on DISH and is available as an easy to learn path for processing scan-based data. Finally, the Interim Automated Reduction and Display System (IARDS) is built on UNI-jr and provides an automated reduction package and pseudo real-time display.

  18. Pork in good company? Exploratory analysis of side dishes, beverages, foodscapes and individual characteristics.

    Science.gov (United States)

    Verbeke, Wim; Perez-Cueto, Federico J A; de Barcellos, Marcia Dutra; Grunert, Klaus G

    2013-11-01

    The objective of this study is to explore the association between pork as the main meal component and the choice for side dishes and beverages depending on foodscape and individual characteristics, including overweight and obesity among fresh pork consumers (n=2156) in five European countries (Belgium, Denmark, Germany, Greece and Poland). Males were found to combine pork more with caloric drinking (odds ratio=1.32) and low levels of vegetable intake (odds ratio=1.32) compared to females. Younger consumers were more likely to combine pork with low levels of vegetable intake but less likely to combine pork with sauces or condiments. Heavy users of pork were more likely (odds ratio=1.43) to combine pork with sauces or condiments. The study also found an association between being overweight or obese and higher consumption of carbohydrate rich staple foods (odds ratio=1.30) and caloric drinks (odds ratio=1.30) as side dishes to pork meat. Substantial cross-cultural differences were revealed in line with typical pork consumption and meal composition habits in the respective countries. Finally, this study found that the company of family plays a significant role when choosing side dishes for pork as meal center, thus constituting a relevant venue for the positioning and marketing of pork, as well as for future public health information about meals with pork as main meal component.

  19. Primary Beam and Dish Surface Characterization at the Allen Telescope Array by Radio Holography

    CERN Document Server

    Atkinson, Shannon; Backus, P R; Barott, William; Bauermeister, Amber; Blitz, Leo; Bock, D C -J; Bower, Geoffrey C; Bradford, Tucker; Cheng, Calvin; Croft, Steve; Dexter, Matt; Dreher, John; Engargiola, Greg; Fields, Ed; Heiles, Carl; Helfer, Tamara; Jordan, Jane; Jorgensen, Susan; Kilsdonk, Tom; Gutierrez-Kraybill, Colby; Keating, Garrett; Law, Casey; Lugten, John; MacMahon, D H E; McMahon, Peter; Milgrome, Oren; Siemion, Andrew; Smolek, Ken; Thornton, Douglas; Pierson, Tom; Randall, Karen; Ross, John; Shostak, Seth; Tarter, J C; Urry, Lynn; Werthimer, Dan; Williams, Peter K G; Whysong, David; Harp, G R; Ackermann, R F; Nadler, Z J; Blair, Samantha K; Davis, M M; Wright, M C H; Forster, J R; DeBoer, D R; Welch, W J

    2012-01-01

    The Allen Telescope Array (ATA) is a cm-wave interferometer in California, comprising 42 antenna elements with 6-m diameter dishes. We characterize the antenna optical accuracy using two-antenna interferometry and radio holography. The distortion of each telescope relative to the average is small, with RMS differences of 1 percent of beam peak value. Holography provides images of dish illumination pattern, allowing characterization of as-built mirror surfaces. The ATA dishes can experience mm-scale distortions across -2 meter lengths due to mounting stresses or solar radiation. Experimental RMS errors are 0.7 mm at night and 3 mm under worst case solar illumination. For frequencies 4, 10, and 15 GHz, the nighttime values indicate sensitivity losses of 1, 10 and 20 percent, respectively. The ATA.s exceptional wide-bandwidth permits observations over a continuous range 0.5 to 11.2 GHz, and future retrofits may increase this range to 15 GHz. Beam patterns show a slowly varying focus frequency dependence. We prob...

  20. Finite time thermodynamic analysis and optimization of solar-dish Stirling heat engine with regenerative losses

    Directory of Open Access Journals (Sweden)

    Sharma Arjun

    2011-01-01

    Full Text Available The present study investigates the performance of the solar-driven Stirling engine system to maximize the power output and thermal efficiency using the non-linearized heat loss model of the solar dish collector and the irreversible cycle model of the Stirling engine. Finite time thermodynamic analysis has been done for combined system to calculate the finite-rate heat transfer, internal heat losses in the regenerator, conductive thermal bridging losses and finite regeneration process time. The results indicate that exergy efficiency of dish system increases as the effectiveness of regenerator increases but decreases with increase in regenerative time coefficient. It is also found that optimal range of collector temperature and corresponding concentrating ratio are 1000 K~1400 K and 1100~1400, respectively in order to get maximum value of exergy efficiency. It is reported that the exergy efficiency of this dish system can reach the maximum value when operating temperature and concentrating ratio are 1150 K and 1300, respectively.

  1. Method of manufacturing large dish reflectors for a solar concentrator apparatus

    Science.gov (United States)

    Angel, Roger P; Olbert, Blain H

    2011-12-27

    A method of manufacturing monolithic glass reflectors for concentrating sunlight in a solar energy system is disclosed. The method of manufacturing allows large monolithic glass reflectors to be made from float glass in order to realize significant cost savings on the total system cost for a solar energy system. The method of manufacture includes steps of heating a sheet of float glass positioned over a concave mold until the sheet of glass sags and stretches to conform to the shape of the mold. The edges of the dish-shaped glass are rolled for structural stiffening around the periphery. The dish-shaped glass is then silvered to create a dish-shaped mirror that reflects solar radiation to a focus. The surface of the mold that contacts the float glass preferably has a grooved surface profile comprising a plurality of cusps and concave valleys. This grooved profile minimizes the contact area and marring of the specular glass surface, reduces parasitic heat transfer into the mold and increases mold lifetime. The disclosed method of manufacture is capable of high production rates sufficiently fast to accommodate the output of a conventional float glass production line so that monolithic glass reflectors can be produced as quickly as a float glass production can make sheets of float glass to be used in the process.

  2. Nano Petri dishes: a new polystyrene platform for studying cell-nanoengineered surface interactions

    Science.gov (United States)

    Cha, Kyoung Je; Na, Moon-Hee; Kim, Hyung Woo; Kim, Dong Sung

    2014-05-01

    In this study, we fabricated and fully characterized a new type of polystyrene (PS) cell-culture platform containing nanoengineered surfaces (NES), referred to as a nano Petri dish, which can be used at the transition stage of basic cell-NES interaction studies for clinical applications. Nano-injection molding in this study was used for the mass production of the nano Petri dish having nanopore arrays. The effects of processing parameters of the injection molding on the replication quality of the nanopore arrays were quantitatively evaluated by means of design of experiments based on the Taguchi method. This allowed efficient and reliable cell culture studies by providing large numbers of the same dishes, in addition to removing the fixation step of the NES plates inside the cell-culture container. Physical, chemical and mechanical properties of the NES, as well as cell behavior including attachment and proliferation of human osteosarcoma MG-63 cells on the NES, were then characterized, with and without the oxygen plasma surface treatment.

  3. An Axi-Symmetric Segmented Composite SKA Dish Design: Performance and Production Analysis

    CERN Document Server

    Ivashina, M V; de Vaate, J G bij; Iupikov, O A; Arts, M; Dekker, J; van Ardenne, A

    2011-01-01

    A concept of an axi-symmetric dish as antenna reflector for the next generation radio telescope - the Square Kilometre Array (SKA) - is presented. The reflector is based on the use of novel thermoplastic composite material (reinforced with carbon fibre) in the context of the telescope design with wide band single pixel feeds. The baseline of this design represents an array of 100's to 1000's reflector antennas of 15-m diameter and covers frequencies from <1 to 10 GHz. The purpose of our study is the analysis of the production cost of the dish and its performance in combination with a realistic wideband feed (such as the 'Eleven Antenna' feed) over a wide frequency band and a range of elevation angles. The presented initial simulation results inidicate the potential of the proposed dish concept for low-cost and mass production and demonstrate sensitivity comparable to that of the presently considered off-set Gregorian reflector antenna with the same projected aperture area. We expect this observation to be ...

  4. The Hydrogen Epoch of Reionization Array Dish I: Beam Pattern Measurements and Science Implications

    CERN Document Server

    Neben, Abraham R; Hewitt, Jacqueline N; DeBoer, David R; Parsons, Aaron R; Aguirre, James E; Ali, Zaki S; Cheng, Carina; Ewall-Wice, Aaron; Patra, Nipanjana; Thyagarajan, Nithyanandan; Bowman, Judd; Dickenson, Roger; Dillon, Joshua S; Doolittle, Phillip; Egan, Dennis; Hedrick, Mike; Jacobs, Daniel C; Kohn, Saul A; Klima, Patricia J; Moodley, Kavilan; Saliwanchik, Benjamin R B; Schaffner, Patrick; Shelton, John; Taylor, H A; Taylor, Rusty; Tegmark, Max; Wirt, Butch; Zheng, Haoxuan

    2016-01-01

    The Hydrogen Epoch of Reionization Array (HERA) is a radio interferometer aiming to detect the power spectrum of 21cm fluctuations from neutral hydrogen from the Epoch of Reionization (EOR). Drawing on lessons from the Murchison Widefield Array (MWA) and the Precision Array for Probing the Epoch of Reionization (PAPER), HERA is a hexagonal array of large (14m diameter) dishes with suspended dipole feeds. Not only does the dish determine overall sensitivity, it affects the observed frequency structure of foregrounds in the interferometer. This is the first of a series of four papers characterizing the frequency and angular response of the dish with simulations and measurements. We focus in this paper on the angular response (i.e., power pattern), which sets the relative weighting between sky regions of high and low delay, and thus, apparent source frequency structure. We measure the angular response at 137MHz using the ORBCOMM beam mapping system of Neben et al. We measure a collecting area of 93m^2 in the opt...

  5. Theory of Parabolic Arcs in Interstellar Scintillation Spectra

    CERN Document Server

    Cordes, J M; Stinebring, D R; Coles, W A; Cordes, James M.; Rickett, Barney J.; Stinebring, Daniel R.; Coles, William A.

    2004-01-01

    Our theory relates the secondary spectrum, the 2D power spectrum of the radio dynamic spectrum, to the scattered pulsar image in a thin scattering screen geometry. Recently discovered parabolic arcs in secondary spectra are generic features for media that scatter radiation at angles much larger than the rms scattering angle. Each point in the secondary spectrum maps particular values of differential arrival-time delay and fringe rate (or differential Doppler frequency) between pairs of components in the scattered image. Arcs correspond to a parabolic relation between these quantities through their common dependence on the angle of arrival of scattered components. Arcs appear even without consideration of the dispersive nature of the plasma. Arcs are more prominent in media with negligible inner scale and with shallow wavenumber spectra, such as the Kolmogorov spectrum, and when the scattered image is elongated along the velocity direction. The arc phenomenon can be used, therefore, to constrain the inner scal...

  6. Polarization properties of linearly polarized parabolic scaling Bessel beams

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Mengwen; Zhao, Daomu, E-mail: zhaodaomu@yahoo.com

    2016-10-07

    The intensity profiles for the dominant polarization, cross polarization, and longitudinal components of modified parabolic scaling Bessel beams with linear polarization are investigated theoretically. The transverse intensity distributions of the three electric components are intimately connected to the topological charge. In particular, the intensity patterns of the cross polarization and longitudinal components near the apodization plane reflect the sign of the topological charge. - Highlights: • We investigated the polarization properties of modified parabolic scaling Bessel beams with linear polarization. • We studied the evolution of transverse intensity profiles for the three components of these beams. • The intensity patterns of the cross polarization and longitudinal components can reflect the sign of the topological charge.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Parabolic discounting of monetary rewards by physical effort.

    Science.gov (United States)

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

    2013-11-01

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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. Inverse Coefficient Problems for Nonlinear Parabolic Differential Equations

    Institute of Scientific and Technical Information of China (English)

    Yun Hua OU; Alemdar HASANOV; Zhen Hai LIU

    2008-01-01

    This paper is devoted to a class of inverse problems for a nonlinear parabolic differential equation.The unknown coefficient of the equation depends on the gradient of the solution and belongs to a set of admissible coefficients.It is proved that the convergence of solutions for the corresponding direct problems continuously depends on the coefficient convergence.Based on this result the existence of a quasisolution of the inverse problem is obtained in the appropriate class of admissible coefficients.

  13. Local H\\"older continuity for doubly nonlinear parabolic equations

    CERN Document Server

    Kuusi, Tuomo; Urbano, José Miguel

    2010-01-01

    We give a proof of the H\\"older continuity of weak solutions of certain degenerate doubly nonlinear parabolic equations in measure spaces. We only assume the measure to be a doubling non-trivial Borel measure which supports a Poincar\\'e inequality. The proof discriminates between large scales, for which a Harnack inequality is used, and small scales, that require intrinsic scaling methods.

  14. Regularity problem for quasilinear elliptic and parabolic systems

    CERN Document Server

    Koshelev, Alexander

    1995-01-01

    The smoothness of solutions for quasilinear systems is one of the most important problems in modern mathematical physics. This book deals with regular or strong solutions for general quasilinear second-order elliptic and parabolic systems. Applications in solid mechanics, hydrodynamics, elasticity and plasticity are described. The results presented are based on two main ideas: the universal iterative method, and explicit, sometimes sharp, coercivity estimates in weighted spaces. Readers are assumed to have a standard background in analysis and PDEs.

  15. Quantum product and parabolic orbits in homogeneous spaces

    CERN Document Server

    Pech, Clélia

    2012-01-01

    Chaput, Manivel and Perrin proved a formula describing the quantum product by Schubert classes associated to cominuscule weights in a rational projective homogeneous space X. In the case where X has Picard rank one, we link this formula to the stratification of X by P-orbits, where P is the parabolic subgroup associated to the cominuscule weight. We deduce a decomposition of the Hasse diagram of X, i.e the diagram describing the cup-product with the hyperplane class.

  16. Long term behaviour of singularly perturbed parabolic degenerated equation

    Directory of Open Access Journals (Sweden)

    Ibrahima Faye

    2016-12-01

    Full Text Available In this paper we consider models built in [4] for short-term, mean-term and long-term morphodynamics of dunes and megariples. We give an existence and uniqueness result for long term dynamics of dunes. This result is based on a periodic-in-time-and-space solution existence result for degenerated parabolic equation that we set out. Finally the mean-term and long-term models are homogenized.

  17. Stability and Boundedness of Solutions to Nonautonomous Parabolic Integrodifferential Equations

    Directory of Open Access Journals (Sweden)

    Michael Gil'

    2016-01-01

    Full Text Available We consider a class of linear nonautonomous parabolic integrodifferential equations. We will assume that the coefficients are slowly varying in time. Conditions for the boundedness and stability of solutions to the considered equations are suggested. Our results are based on a combined usage of the recent norm estimates for operator functions and theory of equations on the tensor product of Hilbert spaces.

  18. Performance of a blood chemistry analyzer during parabolic flight

    Science.gov (United States)

    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.

  19. Parabolic-trough solar collectors and their applications

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Garcia, A.; Zarza, E.; Valenzuela, L. [CIEMAT-Plataforma Solar de Almeria, Ctra. Senes, km. 4, Tabernas (Almeria) 04200 (Spain); Perez, M. [Departamento de Fisica Aplicada, Universidad de Almeria, Almeria 04120 (Spain)

    2010-09-15

    This paper presents an overview of the parabolic-trough collectors that have been built and marketed during the past century, as well as the prototypes currently under development. It also presents a survey of systems which could incorporate this type of concentrating solar system to supply thermal energy up to 400 C, especially steam power cycles for electricity generation, including examples of each application. (author)

  20. APPROXIMATE CONTROLLABILITY OF A CLASS OF QUASILINEAR PARABOLIC EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    Wang Chunpeng; Yin Jingxue; Huang Xingbo

    2002-01-01

    In this paper we study the approximate controllability of a class ofquasilinear parabolic equations in a bounded spacial domain Ω RN when the controlacts on any open and nonempty subset of Ω. The approximate controllability inLp(Ω)for N + 2 ≤ p < +∞ is proved. The proof combines a variational approach to thecontrollability problem for linear equations and a fixed point method.

  1. Tropospheric Refraction Modeling Using Ray-Tracing and Parabolic Equation

    Directory of Open Access Journals (Sweden)

    P. Pechac

    2005-12-01

    Full Text Available Refraction phenomena that occur in the lower atmospheresignificantly influence the performance of wireless communicationsystems. This paper provides an overview of corresponding computationalmethods. Basic properties of the lower atmosphere are mentioned.Practical guidelines for radiowave propagation modeling in the loweratmosphere using ray-tracing and parabolic equation methods are given.In addition, a calculation of angle-of-arrival spectra is introducedfor multipath propagation simulations.

  2. Null controllability for linear parabolic cascade systems with interior degeneracy

    Directory of Open Access Journals (Sweden)

    Idriss Boutaayamou

    2016-11-01

    Full Text Available We study the null controllability problem for linear degenerate parabolic systems with one control force through Carleman estimates for the associated adjoint problem. The novelty of this article is that for the first time it is considered a problem with an interior degeneracy and a control set that only requires to contain an interval lying on one side of the degeneracy points. The obtained result improves and complements a number of earlier works. As a consequence, observability inequalities are established.

  3. Abacus models for parabolic quotients of affine Weyl groups

    CERN Document Server

    Hanusa, Christopher R H

    2011-01-01

    We introduce abacus diagrams that describe minimal length coset representatives in affine Weyl groups of types B, C, and D. These abacus diagrams use a realization of the affine Weyl group of type C due to Eriksson to generalize a construction of James for the symmetric group. We also describe several combinatorial models for these parabolic quotients that generalize classical results in affine type A related to core partitions.

  4. Schauder estimates for parabolic equation of bi-harmonic type

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Global Schauder estimates for the initial-value parabolic problem of the bi-harmonic type are proved, and the existence and uniqueness of the solutions in the suitable space are obtained. Similarly to the second-order case, first a formal expression of solutions by the Fourier transform is obtained, and then the regularity, uniqueness and existence of solutions using the potential theory and approximation argument are got.out approach is simple and straightforward.

  5. Adaptive Mixed Finite Element Methods for Parabolic Optimal Control Problems

    OpenAIRE

    Zuliang Lu

    2011-01-01

    We will investigate the adaptive mixed finite element methods for parabolic optimal control problems. The state and the costate are approximated by the lowest-order Raviart-Thomas mixed finite element spaces, and the control is approximated by piecewise constant elements. We derive a posteriori error estimates of the mixed finite element solutions for optimal control problems. Such a posteriori error estimates can be used to construct more efficient and reliable adaptive mixed finite element ...

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

    Science.gov (United States)

    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.

  7. Thermal distortion analysis of a deployable parabolic reflector

    Science.gov (United States)

    Bruck, L. R.; Honeycutt, G. H.

    1973-01-01

    A thermal distortion analysis of the ATS-6 Satellite parabolic reflector was performed using NASTRAN level 15.1. The same NASTRAN finite element method was used to conduct a one g static load analysis and a dynamic analysis of the reflector. In addition, a parametric study was made to determine which parameters had the greatest effect on the thermal distortions. The method used to model the construction of the reflector is described and the results of the analyses are presented.

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

    Science.gov (United States)

    Chafee, N.

    1973-01-01

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

  9. Gradient estimates for parabolic and elliptic systems from linear laminates

    CERN Document Server

    Dong, Hongjie

    2012-01-01

    We establish several gradient estimates for second-order divergence type parabolic and elliptic systems. The coefficients and data are assumed to be H\\"older or Dini continuous in the time variable and all but one spatial variables. This type of systems arises from the problems of linearly elastic laminates and composite materials. For the proof, we use Campanato's approach in a novel way. Non-divergence type equations under a similar condition are also discussed.

  10. Long term behaviour of singularly perturbed parabolic degenerated equation

    CERN Document Server

    Faye, Ibrahima; Seck, Diaraf

    2011-01-01

    In this paper we consider models for short-term, mean-term and long-term morphodynamics of dunes and megariples. We give an existence and uniqueness result for long term dynamics of dunes. This result is based on a time-space periodic solution existence result for degenerated parabolic equation that we set out. Finally the mean-term and long-term models are homogenized.

  11. Discontinuous Mixed Covolume Methods for Linear Parabolic Integrodifferential Problems

    Directory of Open Access Journals (Sweden)

    Ailing Zhu

    2014-01-01

    Full Text Available The semidiscrete and fully discrete discontinuous mixed covolume schemes for the linear parabolic integrodifferential problems on triangular meshes are proposed. The error analysis of the semidiscrete and fully discrete discontinuous mixed covolume scheme is presented and the optimal order error estimate in discontinuous H(div and first-order error estimate in L2 are obtained with the lowest order Raviart-Thomas mixed element space.

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

    Science.gov (United States)

    Gómez, José; López-Moliner, Joan

    2013-01-01

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

  13. Monte Carlo method for solving a parabolic problem

    Directory of Open Access Journals (Sweden)

    Tian Yi

    2016-01-01

    Full Text Available In this paper, we present a numerical method based on random sampling for a parabolic problem. This method combines use of the Crank-Nicolson method and Monte Carlo method. In the numerical algorithm, we first discretize governing equations by Crank-Nicolson method, and obtain a large sparse system of linear algebraic equations, then use Monte Carlo method to solve the linear algebraic equations. To illustrate the usefulness of this technique, we apply it to some test problems.

  14. Theoretical analysis of a parabolic torus reflector antenna with multibeam

    Institute of Scientific and Technical Information of China (English)

    杜彪; 杨可忠; 钟顺时

    1995-01-01

    The parametric equations and the formulas of unit normal vector and surface element for aparabolic torus reflector antenna are derived and the mechanism of producing multibeam is proposed, Based on physical optics, the radiation pattern formulas for the antenna are given, with which the effects of geometric parameters on the antenna are studied. The good agreement between the calculated patterns and the measured ones shows that the theory is helpful for designing parabolic torus antennas.

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

    Directory of Open Access Journals (Sweden)

    José eGómez

    2013-05-01

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

  16. Cabbage Dish

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    Ingredients: 500 grams of cabbage, 40 grams of winter bamboo shoots, 40 grams of rehydrated winter mushrooms, 20 grams of green pepper, 20 grams of red pepper, 30 grams of scallions, 10 grams of ginger, 20-40 grams of chili pepper, 50 grams of salt, 50

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

    Science.gov (United States)

    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.

  18. Asymptotic analysis of a coupled nonlinear parabolic system

    Institute of Scientific and Technical Information of China (English)

    Lan QIAO; Sining ZHENG

    2008-01-01

    This paper deals with asymptotic analysis of a parabolic system with inner absorptions and coupled nonlinear boundary fluxes. Three simultaneous blow-up rates are established under different dominations of nonlinearities, and simply represented in a characteristic algebraic system introduced for the problem. In particular, it is observed that two of the multiple blow-up rates are absorption-related. This is substantially different from those for nonlinear parabolic problems with absorptions in all the previous literature, where the blow-up rates were known as absorption-independent. The results of the paper rely on the scaling method with a complete classification for the nonlinear parameters of the model. The first example of absorption-related blow-up rates was recently proposed by the authors for a coupled parabolic system with mixed type nonlinearities. The present paper shows that the newly observed phenomena of absorption-related blow-up rates should be due to the coupling mechanism, rather than the mixed type nonlinearities.

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

    Science.gov (United States)

    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.

  20. Convergence of shock waves between conical and parabolic boundaries

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2016-05-01

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

  2. Personality traits of people attracted by parabolic flight.

    Science.gov (United States)

    Collado, Aurélie; Monfort, Vincent; Hainaut, Jean-Philippe; Rosnet, Elisabeth; Bolmont, Benoît

    2014-01-01

    Studies have shown that members of expeditions in extreme environments differed on the basis of personality factors (e.g., they were highly competitive, higher on Extraversion and Conscientiousness) compared to the control population. In order to identify individuals who are likely to participate in extreme environments, the aim of the present study using parabolic flights was to compare the personality traits of voluntary participants (VP) in a weightlessness experiment with those of the general population (GP) (French norms). The personalities of 57 voluntary participants in a parabolic flights experiment were assessed using NEO-PI-R and Trait-Anxiety. Our results show significant differences with the general population: (1) in Trait-Anxiety (GP = 42.25 +/- 11.44 vs. VP = 34.56 +/- 6.24) and in 3 out of 5 personality domains (Neuroticism GP = 90.04 +/- 22.68 vs. VP = 78.70 +/- 17.44, +/- 18.87 vs. VP = 123.81 +/- 15.41, and Conscientiousness GP = 109.23 +/- 22.30 vs. VP = 124.47 + 19.03); and (2) in 14 out of 30 NEO-PI-R facets. These findings indicate a specific personality profile for voluntary participants in parabolic flights and confirm that participants attracted to extreme environments differ compared to the normative population.

  3. 碟式斯特林发电系统性能分析模型与仿真%Dish-Stifling power generation system performance prediction model and simulation analysis

    Institute of Scientific and Technical Information of China (English)

    李明震; 董金钟

    2013-01-01

    基于传热学、热力学、动力学、电学理论以及系统控制模型,建立了可用于碟式斯特林发电系统分析、设计、优化和控制的性能分析模型.模型包括太阳能聚光器、接收器、斯特林循环热力学、斯特林发动机机构动力学、起动/发电机等各子系统及相互作用关系,可分析系统从起动到全功率状态时的稳态性能和动态特性.使用该模型对碟式斯特林系统进行了仿真分析,结果表明,在发动机热端温度不变的控制条件下,系统一天内的输出电功率表现出与太阳直射强度类似的抛物形变化,系统效率变化较平稳;系统充气过程压力突增,在太阳直射强度不变的情况下,发动机热端温度下降,发电功率先增加一点,后随温度下降而下降.%A solar dish-Stirling system model was developed for design, optimization, control, and systems development of dish-Stirling systems. It modeled the energy transfer in parabolic concentrator and receiver, cycle thermodynamics and mechanical dynamics in Stirling engine and so on. The model's scope extends from the solar energy to thermal, mechanical, and electrical energy out, helping to study complex system interactions among subsystems. It can be used to simulate the entire range of system operation from start-up to full power conditions. The model details were discussed and the simulation results were given for steady and dynamic phenomena. According to the constant hot-end temperature control strategy, the system output power changes parabolicly with the direct normal insolation and the system efficiency changes slightly in a day. During the feeding process which causing a pressure jump, the hot-end temperature decreases in case of engine speed unchanged, and the output power increases firstly and then decreases to a steady value.

  4. Studies on the Second-Order Nonlinear Optical Properties of Parabolic and Semi-parabolic Quantum Wells with Applied Electric Fields

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li; XIE Hong-Jing

    2004-01-01

    Within the framework of compact density matrix approach and iterative procedure, a detailed procedure for the calculation of the second-harmonic generation (SHG)susceptibility tensor is given in the electric-field-biased parabolic and semi-parabolic quantum wells (QWs). The simple analytical formula for the SHG susceptibility in the systems is also deduced. Numerical results on typical AlGaAs/GaAs materials show that, for the same effective width,the SHG susceptibility in semi-parabolic QW is larger than that in parabolic QW due to the self-asymmetry of the semiparabolic QW, and the applied electric field can make the SHG susceptibilities in both systems enhance remarkably.Moreover, the SHG susceptibility is also related to the parabolic confinement frequency and the relaxation rate of the systems.

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

    Science.gov (United States)

    Daners, Daniel; Thornett, Christopher

    2016-07-01

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

  6. Asymptotic Properties of Solutions of Parabolic Equations Arising from Transient Diffusions

    Institute of Scientific and Technical Information of China (English)

    A.M. Il'in; R.Z. Khasminskii; G. Yin

    2002-01-01

    This work is concerned with asymptotic properties of a class of parabolic systems arising from singularly perturbed diffusions. The underlying system has a fast varying component and a slowly changing component. One of the distinct features is that the fast varying diffusion is transient. Under such a setup, this paper presents an asymptotic analysis of the solutions of such parabolic equations. Asymptotic expansions of functional satisfying the parabolic system are obtained. Error bounds are derived.

  7. The design of the local monitor and control system of SKA dishes

    Science.gov (United States)

    Schillirò, F.; Baldini, V.; Becciani, U.; Cirami, R.; Costa, A.; Ingallinera, A.; Marassi, A.; Nicotra, G.; Nocita, C.; Riggi, S.; Trigilio, C.

    2016-08-01

    The Square Kilometer Array (SKA) project aims at building the world's largest radio observatory to observe the sky with unprecedented sensitivity and collecting area. In the first phase of the project (SKA1), an array of dishes, SKA1-MID, will be built in South Africa. It will consist of 133 15m-dishes, which will include the MeerKAT array, for the 0.350-20 GHz frequency band observations. Each antenna will be provided with a local monitor and control system (LMC), enabling operations both to the Telescope Manager remote system, and to the engineers and maintenance staff; it provides different environment for the telescope control (positioning, pointing, observational bands), metadata collection for monitoring and database storaging, operational modes and functional states management for all the telescope capabilities. In this paper we present the LMC software architecture designed for the detailed design phase (DD), where we describe functional and physical interfaces with monitored and controlled sub-elements, and highlight the data flow between each LMC modules and its sub-element controllers from one side, and Telescope Manager on the other side. We also describe the complete Product Breakdown Structure (PBS) created in order to optimize resources allocation in terms of calculus and memory, able to perform required task for each element according to the proper requirements. Among them, time response and system reliability are the most important, considering the complexity of SKA dish network and its isolated placement. Performances obtained by software implementation using TANGO framework will be discussed, matching them with technical requirements derived by SKA science drivers.

  8. Available Energy and Cumulative Frequency Curves for Parabolic Trough Concentrators with Alignment North–South, in the Northwest of Mexico

    Directory of Open Access Journals (Sweden)

    Álvaro Lentz–Herrea

    2009-04-01

    Full Text Available The Northwest of Mexico is a well known region with the highest ambient temperatures along the summer and the highest levels of irradiance, which make it feasible to install solar field concentrators. This work provides beam irradiance data that can be used to design a solar north–south parabolic trough system. The variation between the value of beam solar irradiance estimated by a pyranometer and the direct irradiance received by the aperture area of a parabolic trough concentrator (PTC is well–known as cosθ. This variation was evaluated every day of the year, obtaining values of average irradiance for Cerro Prieto (CP lat. 32°39', long. 115° 21', and San Luis Rio Colorado (SLR lat. 32°30', long. 114°46', with which they were elaborated the available energy and cumulative frequency curves (CFC. These are useful to know the number of hours of field solar concentrators which can operate at different levels of energy, as well as the steam production of a solar–geothermal hybrid system to produce electricity.

  9. The kinematic Stirling engine as an energy conversion subsystem for paraboloidal dish solar thermal plants

    Science.gov (United States)

    Bowyer, J. M.

    1984-01-01

    The potential of a suitably designed and economically manufactured Stirling engine as the energy conversion subsystem of a paraboloidal dish-Stirling solar thermal power module was estimated. Results obtained by elementary cycle analyses were shown to match quite well the performance characteristics of an advanced kinematic Stirling engine, the United Stirling P-40, as established by current prototypes of the engine and by a more sophisticated analytic model of its advanced derivative. In addition to performance, brief consideration was given to other Stirling engine criteria such as durability, reliability, and serviceability. Production costs were not considered here.

  10. Using microdispensing to manufacture a customized cell dish for microbeam irradiation of single, living cells

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, E.J.C. [Division of Nuclear Physics, Department of Physics, Lund Institute of Technology, Lund University, Box 118, S-22100 Lund (Sweden)], E-mail: charlotta.nilsson@nuclear.lu.se; Olsson, M.G. [Division of Infection Medicine, Department of Clinical Sciences, Lund University, S-22184 Lund (Sweden); Nilsson, J. [Department of Electrical Measurements and Industrial Electrical Engineering and Automation, Lund Institute of Technology, Lund University, Box 118, S-22100 Lund (Sweden); Pallon, J.; Masternak, A. [Division of Nuclear Physics, Department of Physics, Lund Institute of Technology, Lund University, Box 118, S-22100 Lund (Sweden); Paczesny, J. [Division of Nuclear Physics, Department of Physics, Lund Institute of Technology, Lund University, Box 118, S-22100 Lund (Sweden); Division of Infection Medicine, Department of Clinical Sciences, Lund University, S-22184 Lund (Sweden); Arteaga-Marrero, N.; Elfman, M.; Kristiansson, P.; Nilsson, C. [Division of Nuclear Physics, Department of Physics, Lund Institute of Technology, Lund University, Box 118, S-22100 Lund (Sweden); Akerstroem, B. [Division of Infection Medicine, Department of Clinical Sciences, Lund University, S-22184 Lund (Sweden)

    2009-04-15

    In this paper is described the preparation of patterned cell dishes to be used in studies of low dose irradiation effects on living cells. Using a droplet microdispenser, an 8 {mu}m thick polypropylene cell substrate, to which cells do not naturally adhere, was coated in a matrix pattern with the cell adhesive mussel protein Cell-Tak. Cells were shown to adhere and grow on the protein-coated spots, but not on the uncoated parts, providing for guided cell growth. Cultivation of isolated cell colonies provides an opportunity to study how low doses of ionizing radiation affect neighbouring un-irradiated cell colonies.

  11. Immobilization of sericin molecules via amorphous carbon plasma modified-polystyrene dish for serum-free culture

    Energy Technology Data Exchange (ETDEWEB)

    Tunma, Somruthai [The Graduate School, Chiang Mai University, 239 Huay Kaew Road, Muang District, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics (ThEP), 239 Huay Kaew Road, Muang District, Chiang Mai 50200 (Thailand); Song, Doo-Hoon [Research Center for Orofacial Hard Tissue Regeneration, College of Dentistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Kim, Si-Eun; Kim, Kyoung-Nam [Research Center for Orofacial Hard Tissue Regeneration, College of Dentistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Department and Research Institute of Dental Biomaterials and Bioengineering, College of Dentistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Han, Jeon-Geon [Center for Advanced Plasma Surface Technology, Sungkyunkwan University, 300 Chunchun-dong, Jangan-gu, Suwon 440-746 (Korea, Republic of); Boonyawan, Dheerawan, E-mail: dheerawan.b@cmu.ac.th [Thailand Center of Excellence in Physics (ThEP), 239 Huay Kaew Road, Muang District, Chiang Mai 50200 (Thailand); Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, 239 Huay Kaew Road, Muang District, Chiang Mai 50200 (Thailand)

    2013-10-15

    In this study, we focused on sericin hydrolysates, originating from silkworm used in serum-free human bone marrow-derived mesenchymal stem cells (hBM-MSCs) culture. We reported the effect of a covalent linkage between a bioactive protein molecule and polystyrene dish surface via a carbon intermediate layer which can slow down the release rate of protein compounds into the phosphate buffer saline (PBS) solution. Films of amorphous carbon (a-C) and functionalized-carbon were deposited on PS culture dish surfaces by using a DC magnetron sputtering system and RF PECVD system. We found that a-C based-films can increase the hydrophilicity and biocompatibility of polystyrene (PS) dishes, especially a-C films and a-C:N{sub 2} films showed good attachment of hBM-MSCs at 24 h. However, in the case of silica surface (a-C:SiO{sub x} films), the cells showed a ragged and unattached boundary resulting from the presence of surface silanol groups. For the UV–vis absorbance, all carbon modified-PS dishes showed a lower release rate of sericin molecules into PBS solution than PS control. This revealed that the functionalized carbon could be enhanced by specific binding properties with given molecules. The carbon-coated PS dishes grafting with sericin protein were used in a serum-free condition. We also found that hBM-MSCs have higher percentage of proliferated cells at day 7 for the modified dishes with carbon films and coated with sericin than the PS control coated with sericin. The physical film properties were measured by atomic force microscopy (AFM), scanning electron microscope (SEM) and contact angle measurement. The presence of -NH{sub 2} groups of sericin compounds on the PS dish was revealed by Fourier transform infrared spectroscopy (FTIR). The stability of covalent bonds of sericin molecules after washing out ungrafted sericin was confirmed by X-ray photoelectron spectroscopy (XPS).

  12. A cell complex structure for the space of heteroclines for a semilinear parabolic equation

    Directory of Open Access Journals (Sweden)

    Michael Robinson

    2009-01-01

    Full Text Available It is well known that for many semilinear parabolic equations there is a global attractor which has a cell complex structure with finite dimensional cells. Additionally, many semilinear parabolic equations have equilibria with finite dimensional unstable manifolds. In this article, these results are unified to show that for a specific parabolic equation on an unbounded domain, the space of heteroclinic orbits has a cell complex structure with finite dimensional cells. The result depends crucially on the choice of spatial dimension and the degree of the nonlinearity in the parabolic equation, and thereby requires some delicate treatment.

  13. Error Analysis for Discontinuous Galerkin Method for Parabolic Problems

    Science.gov (United States)

    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.

  14. Validation of a Dish-Based Semiquantitative Food Questionnaire in Rural Bangladesh

    Directory of Open Access Journals (Sweden)

    Pi-I. D. Lin

    2017-01-01

    Full Text Available A locally validated tool was needed to evaluate long-term dietary intake in rural Bangladesh. We assessed the validity of a 42-item dish-based semi-quantitative food frequency questionnaire (FFQ using two 3-day food diaries (FDs. We selected a random subset of 47 families (190 participants from a longitudinal arsenic biomonitoring study in Bangladesh to administer the FFQ. Two 3-day FDs were completed by the female head of the households and we used an adult male equivalent method to estimate the FD for the other participants. Food and nutrient intakes measured by FFQ and FD were compared using Pearson’s and Spearman’s correlation, paired t-test, percent difference, cross-classification, weighted Kappa, and Bland–Altman analysis. Results showed good validity for total energy intake (paired t-test, p < 0.05; percent difference <10%, with no presence of proportional bias (Bland–Altman correlation, p > 0.05. After energy-adjustment and de-attenuation for within-person variation, macronutrient intakes had excellent correlations ranging from 0.55 to 0.70. Validity for micronutrients was mixed. High intraclass correlation coefficients (ICCs were found for most nutrients between the two seasons, except vitamin A. This dish-based FFQ provided adequate validity to assess and rank long-term dietary intake in rural Bangladesh for most food groups and nutrients, and should be useful for studying dietary-disease relationships.

  15. [Dysphagia caused by neurogenic deglutition disorders and diffuse idiopathic skeletal hyperostosis (DISH)].

    Science.gov (United States)

    Bremke, M; Wagner, H-J; Folz, B J

    2006-09-01

    Diffuse idiopathic skeletal hyperostosis (DISH) may lead to dysphagia caused by osteophytes of the cervical spine. Osteophytes can be resected transorally or transcervically, but operative ablation should not be indicated generously because of the threat of severe complications. A fifty-year-old man with dysphagia and loss of weight of 15 kg in the last three months is presented. He also suffered from a brain damage during infancy which caused grand-mal-seizures. One seizure lead to cardiac arrest which required cardio-pulmonary resuscitation and subsequent tracheostomy. A spheric tumor of the posterior pharyngeal wall could be seen endoscopically, it appeared radiologically as an osteophytic formation of the segments C (3) - C (5). Ossification of the anterior longitudinal ligament was also seen. Diagnosis of DISH was made on the basis of these results. Contrast imaging of the esophagus and videofluoroscopy showed aspiration in terms of neurogenic disorders. The patient received a percutaneous gastrostomy after his case was discussed with neurologic and orthopaedic colleagues, because a causal therapy of the combined disease seemed to be impossible. Dysphagia in the presented case was caused by a combination of neurogenic deglutition disorders and oropharyngeal obstruction through osteophytes. Surgical removal of the osteophytes was not indicated because it would have put the patient at a certain risk, but only a part of the underlying problem would have been removed. Symptomatic therapy with a gastrostomy secures normocaloric diet. The patient's weight remained stable and he can follow his habitual daily routine.

  16. Reflux heat-pipe solar receivers for dish-electric systems

    Science.gov (United States)

    Andraka, Charles E.; Diver, Richard B.

    1988-04-01

    The feasibility of competitive, modular bulk electric power from the sun may be greatly enhanced by the use of a reflux heat pipe receiver to combine a heat engine with a paraboloidal dish concentrator. This combination represents a potential improvement over previous successful demonstrations of dish-electric technology in terms of enhanced performance, lower cost, longer life, and greater flexibility in engine design. In the reflux (i.e., gravity assisted) heat pipe receiver, concentrated solar radiation causes liquid metal (sodium, potassium, or NaK) to evaporate. The vapor flows to the engine interface heat exchanger, where it condenses and releases the latent heat. The condensate is returned to the receiver absorber by gravity (refluxing), and distributed over the surface by gravity and/or capillary forces in a wick lining the receiver. It is essentially an adaptation of heat pipe technology to the peculiar requirements of concentrated solar flux, and provides many advantages over conventional heated tub receiver technology. This overview paper describes the current status and future plans for the U.S. Solar Thermal Program reflux receiver development program at Sandia National Laboratories. Current work includes conventional mesh wick receivers, sintered metal wicks, and pool boiler receivers. The relative design merits and concerns of the different approaches and technology development test plans are discussed.

  17. Embryo density may affect embryo quality during in vitro culture in a microwell group culture dish.

    Science.gov (United States)

    Lehner, Adam; Kaszas, Zita; Murber, Akos; Rigo, Janos; Urbancsek, Janos; Fancsovits, Peter

    2017-08-01

    Culturing embryos in groups is a common practice in mammalian embryology. Since the introduction of different microwell dishes, it is possible to identify oocytes or embryos individually. As embryo density (embryo-to-volume ratio) may affect the development and viability of the embryos, the purpose of this study was to assess the effect of different embryo densities on embryo quality. Data of 1337 embryos from 228 in vitro fertilization treatment cycles were retrospectively analyzed. Embryos were cultured in a 25 μl microdrop in a microwell group culture dish containing 9 microwells. Three density groups were defined: Group 1 with 2-4 (6.3-12.5 μl/embryo), Group 2 with 5-6 (4.2-5.0 μl/embryo), and Group 3 with 7-9 (2.8-3.6 μl/embryo) embryos. Proportion of good quality embryos was higher in Group 2 on both days (D2: 18.9 vs. 31.5 vs. 24.7%; p Culturing 5-6 embryos together in a culture volume of 25 μl may benefit embryo quality. As low egg number, position, and distance of the embryos may influence embryo quality, results should be interpreted with caution.

  18. Sensory attributes of dishes containing shrimp paste with different concentrations of glutamate and 5'-nucleotides.

    Science.gov (United States)

    Jinap, S; Ilya-Nur, A R; Tang, S C; Hajeb, P; Shahrim, K; Khairunnisak, M

    2010-10-01

    The shrimp paste called belacan is a traditional umami taste condiment extensively used in Malaysia that is rich in glutamate and 5'-nucleotides. The aim of this study was to determine the concentration of glutamate and 5'-nucleotides of various types of foods prepared with belacan and to measure their sensory attributes. The concentration of free glutamic acid found in different brands of belacan was 180-530mg/100g and in local dishes 601-4207mg/100g. The total amount of 5'-nucleotides in belacan samples ranged from 0.85 to 42.25μg/g. A Quantitative Descriptive Analysis (QDA) using a list of 17 sensory attributes showed a good correlation between belacan concentration in the final food and a range of positive sensory attributes, except for bitter, sweet, sour taste and astringency. Belacan also contains bitter, sweet and sour compounds that change the positive attributes of belacan at higher concentrations. The highest aroma attributes were linked to nasi goreng belacan (belacan fried rice) while the highest flavour attributes were found in sambal belacan. There was a 32 folds significant increase of umami attributes with the addition of belacan to final foods. The optimum amount of belacan was 0.45% for asam pedas (tamarind flavoured dish with belacan), 18% for sambal belacan (chilli belacan), 1.5-2.5% for kangkong goreng belacan (stir fried water convolous with belacan), and 2% for nasi goreng belacan.

  19. Detailed Performance Analysis of the 10-Kw CNRS-Promes Dish/Stirling System

    Energy Technology Data Exchange (ETDEWEB)

    Reinalter, W.; Ulmer, S.; Heller, P.; Rauch, T.; Gineste, J. M.; Ferriere, A.; Nepveu, F.

    2006-07-01

    The CNRS-Promes dish/Stirling system was erected in June 2004 as the last of three country reference units built in the Envirodish project, partly financed by the German ministry of environment. It represents the latest development step of the EuroDish system with many improved components. With a measured peak of 11 kW electrical output power it is also the best performing system so far. The measurement campaign to determine the optical and thermodynamic efficiency of the system is presented. The optical quality of the concentrator and the energy input to the power conversion unit was measured with a classical flux-mapping system using a Lambertian target and a CCD camera system. For the thermodynamic analysis all the data necessary for a complete energy balance around the Stirling engine, i.e. efficiency of the Stirling motor, the cavity and the receiver as well as the parasitic losses were measured or approximated by calculations. Such a detailed performance analysis helps to quantify all significant losses of the system and to identify the most rewarding future improvements. (Author)

  20. Increasing Powers in a Degenerate Parabolic Logistic Equation

    Institute of Scientific and Technical Information of China (English)

    José Francisco RODRIGUES; Hugo TAVARES

    2013-01-01

    The purpose of this paper is to study the asymptotic behavior of the positive solutions of the problem (O)tu-△u =au-b(x)up inΩ×R+,u(0)=u0,u(t)│(o)Ω =0,as p → +∞,where Ω is a bounded domain,and b(x) is a nonnegative function.The authors deduce that the limiting configuration solves a parabolic obstacle problem,and afterwards fully describe its long time behavior.

  1. Theoretical Study of the Compound Parabolic Trough Solar Collector

    Directory of Open Access Journals (Sweden)

    Dr. Subhi S. Mahammed

    2012-06-01

    Full Text Available Theoretical design of compound parabolic trough solar collector (CPC without tracking is presented in this work. The thermal efficiency is obtained by using FORTRAN 90 program. The thermal efficiency is between (60-67% at mass flow rate between (0.02-0.03 kg/s at concentration ratio of (3.8 without need to tracking system.The total and diffused radiation is calculated for Tikrit city by using theoretical equations. Good agreement between present work and the previous work.

  2. Singular solutions of doubly singular parabolic equations with absorption

    Directory of Open Access Journals (Sweden)

    Yuanwei Qi

    2000-11-01

    Full Text Available In this paper we study a doubly singular parabolic equation with absorption, $$ u_t = hbox{ m div} ( |abla u^m|^{p-2}abla u^m -u^q $$ with $m>0$, $p>1$, $m(p-11$. We give a complete classification of solutions, which we call singular, that are non-negative, non-trivial, continuous in ${mathbb R}^n imes [0, inftybackslash{(0,0} $, and satisfy $u(x,0=0$ for all $xeq 0$. Applications of similar but simpler equations show that these solutions are very important in the study of intermediate asymptotic behavior of general solutions.

  3. Compound parabolic concentrator technology development to commercial solar detoxification applications

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, J.; Malato, S.; Fernandez, P. [CIEMAT, Plataforma Solar de Almeria (ES)] (and others)

    1999-07-01

    An EC-DGXII BRITE-EURAM-III-financed project called Solar detoxification technology in the treatment of persistent non-biodegradable chlorinated industrial water contaminants' is described. The objectives are to develop a simple, efficient and commercially competitive solar water treatment technology based on compound parabolic collectors (CPC) enabling design and erection of turnkey installations. A European industrial consortium, SOLARDETOX, representing industry and research in Spain, Portugal, Germany and Italy has been created through this project. Some of the most up-to-date scientific and technological results are given, including the design of the first industrial European solar detoxification treatment plant, the main project deliverable. (author)

  4. Wavelet Method for Numerical Solution of Parabolic Equations

    Directory of Open Access Journals (Sweden)

    A. H. Choudhury

    2014-01-01

    Full Text Available We derive a highly accurate numerical method for the solution of parabolic partial differential equations in one space dimension using semidiscrete approximations. The space direction is discretized by wavelet-Galerkin method using some special types of basis functions obtained by integrating Daubechies functions which are compactly supported and differentiable. The time variable is discretized by using various classical finite difference schemes. Theoretical and numerical results are obtained for problems of diffusion, diffusion-reaction, convection-diffusion, and convection-diffusion-reaction with Dirichlet, mixed, and Neumann boundary conditions. The computed solutions are highly favourable as compared to the exact solutions.

  5. HOMOGENIZATION OF SEMILINEAR PARABOLIC EQUATIONS IN PERFORATED DOMAINS

    Institute of Scientific and Technical Information of China (English)

    P.DONATO; A. NABIL

    2004-01-01

    This paper is devoted to the homogenization of a semilinear parabolic equation with rapidly oscillating coefficients in a domain periodically perforated by e-periodic holes of size ε. A Neumann condition is prescribed on the boundary of the holes.The presence of the holes does not allow to prove a compactness of the solutions in L2. To overcome this difficulty, the authors introduce a suitable auxiliary linear problem to which a corrector result is applied. Then, the asymptotic behaviour of the semilinear problem as e → 0 is described, and the limit equation is given.

  6. ON A PARABOLIC FREE BOUNDARY EQUATION MODELING PRICE FORMATION

    KAUST Repository

    MARKOWICH, P. A.

    2009-10-01

    We discuss existence and uniqueness of solutions for a one-dimensional parabolic evolution equation with a free boundary. This problem was introduced by Lasry and Lions as description of the dynamical formation of the price of a trading good. Short time existence and uniqueness is established by a contraction argument. Then we discuss the issue of global-in-time-extension of the local solution which is closely related to the regularity of the free boundary. We also present numerical results. © 2009 World Scientific Publishing Company.

  7. Invariant sets for discontinuous parabolic area-preserving torus maps

    CERN Document Server

    Ashwin, P; Nishikawa, T; Zyczkowski, K; Ashwin, Peter; Fu, Xin-Chu; Nishikawa, Takashi; Zyczkowski, Karol

    1999-01-01

    We analyze a class of piecewise linear parabolic maps on the torus, namely those obtained by considering a linear map with double eigenvalue one and taking modulo one in both components. We show that within this two parameter family of maps, the set of noninvertible maps is open and dense. For certain cases (where the entries in the matrix are rational) we show that the maximal invariant set has positive Lebesgue measure and give bounds on the measure. For certain examples we find expressions for the measure of the invariant set.

  8. GENERALIZED DERIVATIONS ON PARABOLIC SUBALGEBRAS OF GENERAL LINEAR LIE ALGEBRAS

    Institute of Scientific and Technical Information of China (English)

    陈正新

    2014-01-01

    Let P be a parabolic subalgebra of a general linear Lie algebra gl(n, F) over a field F, where n ≥ 3, F contains at least n different elements, and char(F) 6= 2. In this article, we prove that generalized derivations, quasiderivations, and product zero derivations of P coincide, and any generalized derivation of P is a sum of an inner derivation, a central quasiderivation, and a scalar multiplication map of P. We also show that any commuting automorphism of P is a central automorphism, and any commuting derivation of P is a central derivation.

  9. Analyzing Parabolic Profile Path for Underwater Towed-Cable

    Institute of Scientific and Technical Information of China (English)

    Vineet KSrivastava

    2014-01-01

    This article discusses the dynamic state analysis of underwater towed-cable when tow-ship changes its speed in a direction making parabolic profile path. A three-dimensional model of underwater towed system is studied. The established governing equations for the system have been solved using the central implicit finite-difference method. The obtained difference non-linear coupled equations are solved by Newton’s method and satisfactory results were achieved. The solution of this problem has practical importance in the estimation of dynamic loading and motion, and hence it is directly applicable to the enhancement of safety and the effectiveness of the offshore activities.

  10. Approximate Solutions of Delay Parabolic Equations with the Dirichlet Condition

    Directory of Open Access Journals (Sweden)

    Deniz Agirseven

    2012-01-01

    Full Text Available Finite difference and homotopy analysis methods are used for the approximate solution of the initial-boundary value problem for the delay parabolic partial differential equation with the Dirichlet condition. The convergence estimates for the solution of first and second orders of difference schemes in Hölder norms are obtained. A procedure of modified Gauss elimination method is used for the solution of these difference schemes. Homotopy analysis method is applied. Comparison of finite difference and homotopy analysis methods is given on the problem.

  11. Space-time isogeometric analysis of parabolic evolution problems

    Science.gov (United States)

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

    2016-07-01

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

  12. Properties of positive solutions to a nonlinear parabolic problem

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper deals with the properties of positive solutions to a quasilinear parabolic equation with the nonlinear absorption and the boundary flux. The necessary and sufficient conditions on the global existence of solutions are described in terms of different parameters appearing in this problem. Moreover, by a result of Chasseign and Vazquez and the comparison principle, we deduce that the blow-up occurs only on the boundary (?)Ω. In addition, for a bounded Lipschitz domainΩ, we establish the blow-up rate estimates for the positive solution to this problem with a= 0.

  13. Upper bounds for parabolic equations and the Landau equation

    Science.gov (United States)

    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.

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

    CERN Document Server

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

    2016-01-01

    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 $\\mu$J, 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.

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

    Science.gov (United States)

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

    2017-03-01

    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.

  16. Deterministic homogenization of parabolic monotone operators with time dependent coefficients

    Directory of Open Access Journals (Sweden)

    Gabriel Nguetseng

    2004-06-01

    Full Text Available We study, beyond the classical periodic setting, the homogenization of linear and nonlinear parabolic differential equations associated with monotone operators. The usual periodicity hypothesis is here substituted by an abstract deterministic assumption characterized by a great relaxation of the time behaviour. Our main tool is the recent theory of homogenization structures by the first author, and our homogenization approach falls under the two-scale convergence method. Various concrete examples are worked out with a view to pointing out the wide scope of our approach and bringing the role of homogenization structures to light.

  17. THE SPACE-TIME FINITE ELEMENT METHOD FOR PARABOLIC PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    李宏; 刘儒勋

    2001-01-01

    Adaptive space-time finite element method, continuous in space but discontinuous in time for semi-linear parabolic problems is discussed. The approach is based on a combination of finite element and finite difference techniques. The existence and uniqueness of the weak solution are proved without any assumptions on choice of the spacetime meshes. Basic error estimates in L∞ (L2) norm, that is maximum-norm in time, L2norm in space are obtained. The numerical results are given in the last part and the analysis between theoretic and experimental results are obtained.

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

    Science.gov (United States)

    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 .

  19. Describing Quadratic Cremer Point Polynomials by Parabolic Perturbations

    DEFF Research Database (Denmark)

    Sørensen, Dan Erik Krarup

    1996-01-01

    .Polynomials of the Cremer type correspond to parameters at the boundary of ahyperbolic component of the Mandelbrot set. In this paper we concentrate onthe main cardioid component. We investigate the differences between two-sided(i.e. alternating) and one-sided parabolic perturbations.In the two-sided case, we prove...... external ray accumulating the Cremer point, but having in itsimpression both the Cremer point and its other preimage. We think of the Julia setas containing a "topologists single comb".By tuning, similar results hold on the boundary of any hyperbolic component of theMandelbrot set....

  20. Rotating Parabolic-Reflector Antenna Target in SAR Data: Model, Characteristics, and Parameter Estimation

    Directory of Open Access Journals (Sweden)

    Bin Deng

    2013-01-01

    Full Text Available Parabolic-reflector antennas (PRAs, usually possessing rotation, are a particular type of targets of potential interest to the synthetic aperture radar (SAR community. This paper is aimed to investigate PRA’s scattering characteristics and then to extract PRA’s parameters from SAR returns, for supporting image interpretation and target recognition. We at first obtain both closed-form and numeric solutions to PRA’s backscattering by geometrical optics (GO, physical optics, and graphical electromagnetic computation, respectively. Based on the GO solution, a migratory scattering center model is at first presented for representing the movement of the specular point with aspect angle, and then a hybrid model, named the migratory/micromotion scattering center (MMSC model, is proposed for characterizing a rotating PRA in the SAR geometry, which incorporates PRA’s rotation into its migratory scattering center model. Additionally, we in detail analyze PRA’s radar characteristics on radar cross-section, high-resolution range profiles, time-frequency distribution, and 2D images, which also confirm the models proposed. A maximal likelihood estimator is developed for jointly solving the MMSC model for PRA’s multiple parameters by optimization. By exploiting the aforementioned characteristics, the coarse parameter estimation guarantees convergency upon global minima. The signatures recovered can be favorably utilized for SAR image interpretation and target recognition.

  1. [The consumption of dishes and/or fishy snacks by school youth from Miedzychodzko-Sierakowskie lakes].

    Science.gov (United States)

    Bortnowska, Grazyna; Grotowska, Longina; Goluch-Koniuszy, Zuzanna

    2011-01-01

    The school youth inhabiting Miedzychodzko-Sierakowskie lakes consumed dishes and/or fishy snacks on the similar low level as their peers in other regions of country, mainly breaded fried fishes and partly or highly manufactured products i.e., herrings in sour cream as well as pastes from smoked fishes and canned fishes. Relatively high ranks in rows of preference (liking) and frequency intake were found for carp, herring and cheap cultured panga from import. The presence of bones and specific odour were the factors that mostly affected low consumption of dishes and/or snacks from fishes. It seems that preparation of attractive tasty dishes and/or snacks from fresh fishes could help in youth teaching regarding correct nutritional habits as well as retain tradition of their consumption during adult life.

  2. Thermal and optical efficiency investigation of a parabolic trough collector

    Directory of Open Access Journals (Sweden)

    C. Tzivanidis

    2015-09-01

    Full Text Available Solar energy utilization is a promising Renewable Energy source for covering a variety of energy needs of our society. This study presents the most well-known solar concentrating system, the parabolic trough collector, which is operating efficiently in high temperatures. The simulation tool of this analysis is the commercial software Solidworks which simulates complicated problems with an easy way using the finite elements method. A small parabolic trough collector model is designed and simulated for different operating conditions. The goal of this study is to predict the efficiency of this model and to analyze the heat transfer phenomena that take place. The efficiency curve is compared to a one dimensional numerical model in order to make a simple validation. Moreover, the temperature distribution in the absorber and inside the tube is presented while the heat flux distribution in the outer surface of the absorber is given. The heat convection coefficient inside the tube is calculated and compared with the theoretical one according to the literature. Also the angle efficiency modifier is calculated in order to predict the thermal and optical efficiency for different operating conditions. The final results show that the PTC model performs efficiently and all the calculations are validated.

  3. Water disinfection by solar photocatalysis using compound parabolic collectors

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, P.; Blanco, J.; Sichel, C.; Malato, S. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Plataforma Solar de Almeria (PSA), P.O. Box 22, 04200 Tabernas, Almeria (Spain)

    2005-04-15

    TiO{sub 2} solar photocatalysis has been proven to be a degradation process for aqueous organic contaminant leading to total mineralisation of a large number of compounds. Furthermore, the interest in using this technique for water disinfection has grown in the last decade. Recent publications have reported photokilling of bacteria and viruses by TiO{sub 2} photocatalysis. Therefore, solar photocatalysis disinfection seems to be a very promising process, which could help to improve public health in rural areas of developing countries. The objective of this work was to assess the feasibility of using TiO{sub 2} solar photocatalysis to disinfect water supplies for future applications in developing countries. This article reviews the viability of solar photocatalysis for disinfection in low cost compound parabolic collectors, using sunlight and titanium dioxide semiconductor, both applied as slurry and supported. We report on the bactericidal action of TiO{sub 2} on a pure culture of Escherichia coli with a low cost photoreactor based on compound parabolic collectors. The influence of different experimental set-ups and parameters are also analysed. The results and potential application of the solar photocatalysis technology to water disinfection are studied within the frame of two research EU projects whose objective consist on the development of a fully autonomous solar reactor system to purify drinking water in remote locations of developing countries.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  6. A parabolic velocity-decomposition method for wind turbines

    Science.gov (United States)

    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.

  7. Shock unsteadiness in a thrust optimized parabolic nozzle

    Science.gov (United States)

    Verma, S. B.

    2009-07-01

    This paper discusses the nature of shock unsteadiness, in an overexpanded thrust optimized parabolic nozzle, prevalent in various flow separation modes experienced during start up {(δ P0 /δ t > 0)} and shut down {(δ P0/δ t tube. Shock unsteadiness in the separation region is seen to increase significantly just before the onset of each flow transition, even during steady nozzle operation. The intensity of this measure ( rms level) is seen to be strongly influenced by relative locations of normal and overexpansion shock, the decrease in radial size of re-circulation zone in the back-flow region, and finally, the local nozzle wall contour. During restricted shock separation, the pressure fluctuations in separation region exhibit periodic characteristics rather than the usually observed characteristics of intermittent separation. The possible physical mechanisms responsible for the generation of flow unsteadiness in various separation modes are discussed. The results are from an experimental study conducted in P6.2 cold-gas subscale test facility using a thrust optimized parabolic nozzle of area-ratio 30.

  8. ACCELERATION METHODS OF NONLINEAR ITERATION FOR NONLINEAR PARABOLIC EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    Guang-wei Yuan; Xu-deng Hang

    2006-01-01

    This paper discusses the accelerating iterative methods for solving the implicit scheme of nonlinear parabolic equations. Two new nonlinear iterative methods named by the implicit-explicit quasi-Newton (IEQN) method and the derivative free implicit-explicit quasi-Newton (DFIEQN) method are introduced, in which the resulting linear equations from the linearization can preserve the parabolic characteristics of the original partial differential equations. It is proved that the iterative sequence of the iteration method can converge to the solution of the implicit scheme quadratically. Moreover, compared with the Jacobian Free Newton-Krylov (JFNK) method, the DFIEQN method has some advantages, e.g., its implementation is easy, and it gives a linear algebraic system with an explicit coefficient matrix, so that the linear (inner) iteration is not restricted to the Krylov method. Computational results by the IEQN, DFIEQN, JFNK and Picard iteration meth-ods are presented in confirmation of the theory and comparison of the performance of these methods.

  9. A quasi-linear parabolic system of chemotaxis

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available We consider a quasi-linear parabolic system with respect to unknown functions u and v on a bounded domain of n -dimensional Euclidean space. We assume that the diffusion coefficient of u is a positive smooth function A ( u , and that the diffusion coefficient of v is a positive constant. If A ( u is a positive constant, the system is referred to as so-called Keller-Segel system. In the case where the domain is a bounded domain of two-dimensional Euclidean space, it is shown that some solutions to Keller-Segel system blow up in finite time. In three and more dimensional cases, it is shown that solutions to so-called Nagai system blow up in finite time. Nagai system is introduced by Nagai. The diffusion coefficients of Nagai system are positive constants. In this paper, we describe that solutions to the quasi-linear parabolic system exist globally in time, if the positive function A ( u rapidly increases with respect to u .

  10. Optical properties of Dirac electrons in a parabolic well.

    Science.gov (United States)

    Kim, S C; Lee, J W; Yang, S-R Eric

    2013-09-01

    A single electron transitor may be fabricated using qunatum dots. A good model for the confinement potential of a quantum dot is a parabolic well. Here we consider such a parabolic dot made of graphene. Recently, we found counter intuitively that resonant quasi-boundstates of both positive and negative energies exist in the energy spectrum. The presence of resonant quasi-boundstates of negative energies is a unique property of massless Dirac fermions. As magnetic field B gets smaller the energy width of these states become broader and for sufficiently weak value of B resonant quasi-bound states disappear into a quasi-continuum. In the limit of small B resonant and nonresonant states transform into discrete anomalous states with a narrow probability density peak inside the well and another broad peak under the potential barrier. In this paper we compute the optical strength between resonant quasi-bound states as a function of B, and investigate how the signature of resonant quasi-bound states of Dirac electrons may appear in optical measurements.

  11. Ground Reaction Forces During Reduced Gravity Running in Parabolic Flight.

    Science.gov (United States)

    Cavanagh, Peter; Rice, Andrea; Glauberman, Molly; Sudduth, Amanda; Cherones, Arien; Davis, Shane; Lewis, Michael; Hanson, Andrea; Wilt, Grier

    2017-08-01

    Treadmills have been employed as both a form of exercise and a countermeasure to prevent changes in the musculoskeletal system on almost all NASA missions and many Russian missions since the early Space Shuttle flights. It is possible that treadmills may also be part of exercise programs on future Mars missions and that they may be a component of exercise facilities in lunar or Martian habitats. In order to determine if the ambient gravity on these destinations will provide osteogenic effects while performing exercise on a treadmill, ground reactions forces (GRFs) were measured on eight subjects (six women and two men) running at 6 mph during parabolic flight in Martian and lunar gravity conditions. On average, stride length increased as gravity decreased. The first and second peaks of the GRFs decreased by 0.156 and 0.196 bodyweights, respectively, per 1/10 g change in ambient gravity. Based on comparisons with previously measured GRF during loaded treadmill running on the International Space Station, we conclude that unloaded treadmill running under lunar and Martian conditions during exploration missions is not likely to be an osteo-protective exercise.Cavanagh P, Rice A, Glauberman M, Sudduth A, Cherones A, Davis S, Lewis M, Hanson A, Wilt G. Ground reaction forces during reduced gravity running in parabolic flight. Aerosp Med Hum Perform. 2017; 88(8):730-736.

  12. Parabolic starlike mappings of the unit ball $B^n$

    Directory of Open Access Journals (Sweden)

    Samira Rahrovi

    2016-02-01

    Full Text Available Let $f$ be a locally univalent function on the unit disk $U$. We consider the normalized extensions of $f$ to the Euclidean unit ball $B^nsubseteqmathbb{C}^n$ given by$$Phi_{n,gamma}(f(z=left(f(z_1,(f'(z_1^gammahat{z}right,$$ where $gammain[0,1/2]$, $z=(z_1,hat{z}in B^n$ and$$Psi_{n,beta}(f(z=left(f(z_1,(frac{f(z_1}{z_1}^betahat{z}right,$$in which $betain[0,1]$, $f(z_1neq 0$ and $z=(z_1,hat{z}inB^n$. In the case $gamma=1/2$, the function $Phi_{n,gamma}(f$ reduces to the well known Roper-Suffridge extension operator. By using different methods, we prove that if $f$ is parabolic starlike mapping on $U$ then $Phi_{n,gamma}(f$ and $Psi_{n,beta}(f$ are parabolic starlike mappings on $B^n$.

  13. Chain ordering of hybrid lipids can stabilize domains in saturated/hybrid/cholesterol lipid membranes

    Science.gov (United States)

    Yamamoto, T.; Brewster, R.; Safran, S. A.

    2010-07-01

    We use a liquid-crystal model to predict that hybrid lipids (lipids that have one saturated and one unsaturated tail) can stabilize line interfaces between domains in mixed membranes of saturated lipids, hybrid lipids, and cholesterol (SHC membranes). The model predicts the phase separation of SHC membranes with both parabolic and loop binodals depending on the cholesterol concentration, modeled via an effective pressure. In some cases, the hybrid lipids can reduce the line tension to zero in SHC membranes at temperatures that approach the critical temperature as the pressure is increased. The differences in the hybrid saturated tail conformational order in bulk and at the interface are responsible for the reduction of the line tension.

  14. A comparison principle for singular parabolic equations in the Heisenberg group

    Directory of Open Access Journals (Sweden)

    Pablo Ochoa

    2015-04-01

    Full Text Available In this work, we prove a comparison principle for singular parabolic equations with boundary conditions in the context of the Heisenberg group. In particular, this result applies to interesting equations, such as the parabolic infinite Laplacian, the mean curvature flow equation and more general homogeneous diffusions.

  15. Discrete approximations for singularly perturbed boundary value problems with parabolic layers

    NARCIS (Netherlands)

    Farrell, P.A.; Hemker, P.W.; Shishkin, G.I.

    1995-01-01

    Singularly perturbed boundary value problems for equations of elliptic and parabolic type are studied. For small values of the perturbation parameter, parabolic boundary layers appear in these problems. If classical discretisation methods are used, the solution of the finite difference scheme and th

  16. A posteriori error estimates of spectral method for optimal control problems governed by parabolic equations

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper,we investigate the Legendre Galerkin spectral approximation of quadratic optimal control problems governed by parabolic equations.A spectral approximation scheme for the parabolic optimal control problem is presented.We obtain a posteriori error estimates of the approximated solutions for both the state and the control.

  17. Null exact controllability of the parabolic equations with equivalued surface boundary condition

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available This paper is devoted to showing the null exact controllability for a class of parabolic equations with equivalued surface boundary condition. Our method is based on the duality argument and global Carleman-type estimate for a parabolic operator.

  18. Difference schemes with intrinsic parallelism for quasi-linear parabolic systems

    Institute of Scientific and Technical Information of China (English)

    周毓麟

    1997-01-01

    The boundary value problem for quasi-linear parabolic system is solved by the finite difference method with intrinsic parallelism The existence and uniqueness and convergence theorems of the discrete vector solu tions of the nonlinear difference system with intrinsic parallelism are proved The limiting vector function is just the unique generalized solution of the original problem for the parabolic system

  19. A Two-Species Cooperative Lotka-Volterra System of Degenerate Parabolic Equations

    Directory of Open Access Journals (Sweden)

    Jiebao Sun

    2011-01-01

    parabolic equations. We are interested in the coexistence of the species in a bounded domain. We establish the existence of global generalized solutions of the initial boundary value problem by means of parabolic regularization and also consider the existence of the nontrivial time-periodic solution for this system.

  20. Computing the real parabolic cylinder functions U(a,x), V(a,x)

    NARCIS (Netherlands)

    Gil, A.; Segura, J.; Temme, N.M.

    2006-01-01

    Methods for the computation of real parabolic cylinder functions U(a,x) and V(a,x) and their derivatives are described. We give details on power series, asymptotic series, recursion and quadrature. A combination of these methods can be used for computing parabolic cylinder functions for unrestricted

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

    Science.gov (United States)

    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.

  2. INERTIAL MANIFOLDS FOR NONAUTONOMOUS SEMILINEAR PARABOLIC PARTIAL DIFFERENTIAL EQUATIONS WITH TIME DELAYS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The present paper deals with the long-time behavior of a class of nonautonomous retarded semilinear parabolic differential equations. When the time delays are small enough and the spectral gap conditions hold, the inertial manifolds of the nonautonomous retard parabolic equations are constructed by using the Lyapunov-Perron method.

  3. H(o)lder Continuity of Weak Solutions for Parabolic Equations with Nonstandard Growth Conditions

    Institute of Scientific and Technical Information of China (English)

    Meng XU; Ya Zhe CHEN

    2006-01-01

    In this paper, we investigate the interior regularity including the local boundedness and the interior H(o)lder continuity of weak solutions for parabolic equations of the p(x,t)-Laplacian type. We improve the Moser iteration technique and generalize the known results for the elliptic problem to the corresponding parabolic problem.

  4. Some integral representations and limits for (products of) the parabolic cylinder function

    NARCIS (Netherlands)

    D. Veestraeten

    2015-01-01

    Veestraeten [1] recently derived inverse Laplace transforms for Laplace transforms that contain products of two parabolic cylinder functions by exploiting the link between the parabolic cylinder function and the transition density and distribution functions of the Ornstein-Uhlenbeck process. This pa

  5. Tapering of Polymer Optical Fibers for Compound Parabolic Concentrator Fiber Tip Fabrication

    DEFF Research Database (Denmark)

    Hassan, Hafeez Ul; Fasano, Andrea; Nielsen, Kristian

    2015-01-01

    We propose a process for Polymer Optical Fiber (POF) Compound Parabolic Compound (CPC) tip manufacturing using a heat and pull fiber tapering technique. The POF, locally heated above its glass transition temperature, is parabolically tapered down in diameter, after which it is cut to the desired ...

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

    Science.gov (United States)

    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.

  7. Some integral representations and limits for (products of) the parabolic cylinder function

    NARCIS (Netherlands)

    Veestraeten, D.

    2015-01-01

    Veestraeten [1] recently derived inverse Laplace transforms for Laplace transforms that contain products of two parabolic cylinder functions by exploiting the link between the parabolic cylinder function and the transition density and distribution functions of the Ornstein-Uhlenbeck process. This pa

  8. Vegetable dishes, dairy products and fruits are key items mediating adequate dietary intake for Japanese adults with spinal cord injury.

    Science.gov (United States)

    Tsunoda, N; Inayama, T; Hata, K; Oka, J

    2015-11-01

    This is a cross-sectional study. The objective of this study was to ascertain the essential items mediating adequate dietary intake based on the Japanese Food Guide in common among the transtheoretical model (TTM), self-efficacy (SE) and outcome expectancy (OE). Members of the organization Spinal Injuries Japan. We posted a questionnaire survey to 2731 community-dwelling Japanese adults with spinal cord injury (SCI), and responses from 841 individuals were analyzed. Food intake was assessed as the frequency scores of 10 food items eaten in a daily diet in Japan. The correlations between the frequency scores of food intake and TTM, SE and OE were determined by binominal logistic regression analysis. The frequency scores of food intake were significantly associated with 'To eat vegetable dishes (dishes made mainly from vegetables or potatoes) not less than twice a day', 'To eat green/yellow vegetables not less than twice a day', 'To eat dairy products not less than once a day' and 'To eat fruits not less than once a day' in TTM. 'To eat vegetable dishes (dishes made mainly from vegetables or potatoes) not less than twice a day', 'To eat dairy products not less than once a day' and 'To eat fruits not less than once a day' were significantly associated with the frequency scores of food intake in SE. In OE, no differences were shown. This study finds that vegetable dishes, dairy products and fruits are the key items mediating adequate dietary intake. Dietary guidelines promoting the intake of these dishes for SCI individuals are needed.

  9. Higher-order effects on self-similar parabolic pulse in the microstructured fibre amplifier

    Institute of Scientific and Technical Information of China (English)

    Liu Wei-Ci; Xu Wen-Cheng; Feng Jie; Chen Wei-Cheng; Li Shu-Xian; Lin Song-Hao

    2008-01-01

    By considering higher-order effects, the properties of self-similar parabolic pulses propagating in the microstructured fibre amplifier with a normal group-velocity dispersion have been investigated. The numerical results indicate that the higher-order effects can badly distort self-similar parabolic pulse shape and optical spectrum, and at the same time the peak shift and oscillation appear, while the pulse still reveals highly linear chirp but grows into asymmetry. The influence of different higher-order effects on self-similar parabolic pulse propagation has been analysed. It shows thatthe self-steepening plays a more important role. We can manipulate the geometrical parameters of the microstructured fibre amplifier to gain a suitable dispersion and nonlinearity coefficient which will keep high-quality self-similar parabolic pulse propagation. These results are significant for the further study of self-similar parabolic pulse propagation.

  10. Identification of Plasmonic Modes in Parabolic Cylinder Geometry by Quasi-Separation of Variables.

    Science.gov (United States)

    Kurihara, Kazuyoshi; Otomo, Akira; Yamamoto, Kazuhiro; Takahara, Junichi; Tani, Masahiko; Kuwashima, Fumiyoshi

    This paper describes the plasmonic modes in the parabolic cylinder geometry as a theoretical complement to the previous paper (J Phys A 42:185401) that considered the modes in the circular paraboloidal geometry. In order to identify the plasmonic modes in the parabolic cylinder geometry, analytic solutions for surface plasmon polaritons are examined by solving the wave equation for the magnetic field in parabolic cylindrical coordinates using quasi-separation of variables in combination with perturbation methods. The examination of the zeroth-order perturbation equations showed that solutions cannot exist for the parabolic metal wedge but can be obtained for the parabolic metal groove as standing wave solutions indicated by the even and odd symmetries.

  11. An Examination of Higher-Order Treatments of Boundary Conditions in Split-Step Fourier Parabolic Equation Models

    Science.gov (United States)

    2015-06-01

    HIGHER-ORDER TREATMENTS OF BOUNDARY CONDITIONS IN SPLIT-STEP FOURIER PARABOLIC EQUATION MODELS by Savas Erdim June 2015 Thesis Advisor...CONDITIONS IN SPLIT-STEP FOURIER PARABOLIC EQUATION MODELS 5. FUNDING NUMBERS 6. AUTHOR(S) Savas Erdim 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES... Parabolic equation models solved using the split-step Fourier (SSF) algorithm, such as the Monterey Miami Parabolic Equation model, are commonly used

  12. Modelització i control d'una màquina termosolar Dish-Stirling

    OpenAIRE

    Nieto Estévez, Albert

    2014-01-01

    En aquest projecte es realitza una modelització dinàmica d’un sistema d’energia termosolar concentrada Dish-Stirling i es dissenyen els convertidors estàtics back-to-back per optimitzar la potència extreta. Es presenta un model tèrmic per al sistema de concentració de radiació solar, un model termodinàmic del motor Stirling, el model elèctric d’un generador d’imants permanents i de convertidors de la màquina i de la xarxa. Els models s’implementen en MATLAB Simulink® i s’estudia el comp...

  13. Optical characterization of nonimaging dish concentrator for the application of dense-array concentrator photovoltaic system.

    Science.gov (United States)

    Tan, Ming-Hui; Chong, Kok-Keong; Wong, Chee-Woon

    2014-01-20

    Optimization of the design of a nonimaging dish concentrator (NIDC) for a dense-array concentrator photovoltaic system is presented. A new algorithm has been developed to determine configuration of facet mirrors in a NIDC. Analytical formulas were derived to analyze the optical performance of a NIDC and then compared with a simulated result obtained from a numerical method. Comprehensive analysis of optical performance via analytical method has been carried out based on facet dimension and focal distance of the concentrator with a total reflective area of 120 m2. The result shows that a facet dimension of 49.8 cm, focal distance of 8 m, and solar concentration ratio of 411.8 suns is the most optimized design for the lowest cost-per-output power, which is US$1.93 per watt.

  14. Cardiomyopathy in a dish: using human inducible pluripotent stem cells to model inherited cardiomyopathies.

    Science.gov (United States)

    Kamdar, Forum; Klaassen Kamdar, Andre; Koyano-Nakagawa, Naoko; Garry, Mary G; Garry, Daniel J

    2015-09-01

    Inherited cardiomyopathies, including hypertrophic cardiomyopathy, dilated cardiomyopathies, arrythmogenic right ventricular cardiomyopathy, and other inherited forms of heart failure, represent a unique set of genetically defined cardiovascular disease processes. Unraveling the molecular mechanisms of these deadly forms of human heart disease has been challenging, but recent groundbreaking scientific advances in stem cell technology have allowed for the generation of patient-specific human inducible stem cell (hiPSC)-derived cardiomyocytes (CMs). hiPSC-derived CMs retain the genetic blueprint of the patient, they can be maintained in culture, and they recapitulate the phenotypic characteristics of the disease in vitro, thus serving as a disease in a dish. This review provides an overview of in vitro modeling of inherited cardiomyopathies with the use of patient-specific hiPSC-derived CMs. Copyright © 2015. Published by Elsevier Inc.

  15. Large-area, high-intensity PV arrays for systems using dish concentrating optics

    Energy Technology Data Exchange (ETDEWEB)

    Ward, J.S.; Duda, A.; Zweibel, K.; Coutts, T.J. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    In this paper, the authors report on efforts to fabricate monolithic interconnected modules (MIMs) using III-V semiconductors with bandgaps appropriate for the terrestrial solar spectrum. The small size of the component cells comprising the MIM allows for operation at extremely high flux densities and relaxes the requirement for a small spot size to be generated by the optics. This makes possible a PV option for the large dish concentrator systems that have been developed by the solar thermal community for use with Stirling engines. Additionally, the highly effective back-surface reflector integrated into the MIM design is an effective tool for thermal management of the array. Development of this technology would radically alter the projections for PV manufacturing capacity because of the potential for extremely high power generation per unit area of semiconductor material.

  16. Thermal modeling of a pressurized air cavity receiver for solar dish Stirling system

    Science.gov (United States)

    Zou, Chongzhe; Zhang, Yanping; Falcoz, Quentin; Neveu, Pierre; Li, Jianlan; Zhang, Cheng

    2017-06-01

    A solar cavity receiver model for the dish collector system is designed in response to growing demand of renewable energy. In the present research field, no investigations into the geometric parameters of a cavity receiver have been performed. The cylindrical receiver in this study is composed of an enclosed bottom at the back, an aperture at the front, a helical pipe inside the cavity and an insulation layer on the external surface of the cavity. The influence of several critical receiver parameters on the thermal efficiency is analyzed in this paper: cavity inner diameter and cavity length. The thermal model in this paper is solved considering the cavity dimensions as variables. Implementing the model into EES, each parameter influence is separately investigated, and a preliminary optimization method is proposed.

  17. Automatic Evaluation of Colonies Growth rate of Yeasts incubated in Petri dishes using Mobile Platform

    Directory of Open Access Journals (Sweden)

    Alecsander Pereira Martins

    2015-10-01

    Full Text Available This paper proposes an automatic method based on computer vision implemented in mobile platform capable of monitoring the growth of microbial colonies incubated in Petri dishes. The developed optimized image processing algorithm performs this task without human intervention from images of colonies of the microorganism in different evolution phases. The contribution of this paper is the development of a fast and robust mobile tool to assist bioprocess experts in monitoring the growth of colonies without using the conventional error prone evaluation techniques. The obtained results successfully demonstrated dimensional alterations in colonies in a faster and more precise fashion when compared with the conventional method, with the additional advantage of versatility in producing reliable estimation of the growth rates with higher statistical significance.

  18. Modelling resource consumption for laundry and dish treatment in individual households for various consumer segments

    Energy Technology Data Exchange (ETDEWEB)

    Stamminger, R. [Institute for Agricultural Engineering, Household and Appliance Technology Section, University of Bonn, Nussallee 5, 53115 Bonn (Germany)

    2011-11-15

    Recent research allocates up to 80% of environmental impact in energy and CO2 terms to direct and indirect consumer activities. Various models discussed how this impact can be assigned to specific lifestyles, production and consumption systems, and psychological motives in order to be able to predict and influence these effects. In this work, another approach is followed by showing on the example of laundry and dish washing how well-known factors of the technical status, consumer practices and demographic data allow building up a model to predict the energy and water consumption for these processes. The results show a variation of a factor of 5 between a more sustainable and a more careless behaviour and allow thus to identify levers to influence it. As results can also be easily transformed into monetary values, this may allow influencing the consumer via this channel as he/she can easily understand what may need to be changed.

  19. Radio Astronomy Data Model for Single-Dish Multiple-Feed Telescopes, and Robledo Archive Architecture

    CERN Document Server

    Santander-Vela, J D; Gómez, J F; Verdes-Montenegro, L; Leon, S; Gutíerrez, R; Rodrigo, C; Morata, O; Solano, E; Suárez, O

    2008-01-01

    All the effort that the astrophysical community has put into the development of the Virtual Observatory (VO) has surpassed the non-return point: the VO is a reality today, and an initiative that will self-sustain, and to which all archival projects must adhere. We have started the design of the scientific archive for the DSS-63 70-m antenna at NASA's DSN station in Robledo de Chavela (Madrid). Here we show how we can use all VO proposed data models to build a VO-compliant single-dish, multiple-feed, radio astronomical archive data model (RADAMS) suitable for the archival needs of the antenna. We also propose an exhaustive list of Universal Content Descriptors (UCDs) and FITS keywords for all relevant metadata. We will further refine this data model with the experience that we will gain from that implementation.

  20. Flexible Sheet-Type Sensor for Noninvasive Measurement of Cellular Oxygen Metabolism on a Culture Dish.

    Directory of Open Access Journals (Sweden)

    Mari Kojima

    Full Text Available A novel flexible sensor was developed for the noninvasive oxygen metabolism measurement of cultivated cells and tissues. This device is composed of a transparent double-layered polymer sheet of ethylene-vinyl alcohol (EVOH and poly(dimethylsiloxane (PDMS having an array of microhole structures of 90 μm diameter and 50 μm depth on its surface. All the microhole structures were equipped with a 1-μm-thick optical chemical sensing layer of platinum porphyrin-fluoropolymer on their bottom. The three-dimensional microstructures of the sensor were fabricated by a newly developed simple and low-cost production method named self-aligned hot embossing. The device was designed to be attached slightly above the cells cultivated on a dish to form a temporarily closed microspace over the target cells during measurement. Since the change in oxygen concentration is relatively fast in the microcompartmentalized culture medium, a rapid evaluation of the oxygen consumption rate is possible by measuring the phosphorescence lifetime of the platinum porphyrin-fluoropolymer. The combined use of the device and an automated optical measurement system enabled the high-throughput sensing of cellular oxygen consumption (100 points/min. We monitored the oxygen metabolism of the human breast cancer cell line MCF7 on a Petri dish and evaluated the oxygen consumption rate to be 0.72 ± 0.12 fmol/min/cell. Furthermore, to demonstrate the utility of the developed sensing system, we demonstrated the mapping of the oxygen consumption rate of rat brain slices and succeeded in visualizing a clear difference among the layer structures of the hippocampus, i.e., the cornu ammonis (CA1 and CA3 and dentate gyrus (DG.

  1. Hybrid Baryons

    CERN Document Server

    Page, P R

    2003-01-01

    We review the status of hybrid baryons. The only known way to study hybrids rigorously is via excited adiabatic potentials. Hybrids can be modelled by both the bag and flux-tube models. The low-lying hybrid baryon is N 1/2^+ with a mass of 1.5-1.8 GeV. Hybrid baryons can be produced in the glue-rich processes of diffractive gamma N and pi N production, Psi decays and p pbar annihilation.

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

    Science.gov (United States)

    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.

  3. Evaluation of Surface Slope Irregularity in Linear Parabolic Solar Collectors

    Directory of Open Access Journals (Sweden)

    F. Francini

    2012-01-01

    Full Text Available The paper describes a methodology, very simple in its application, for measuring surface irregularities of linear parabolic collectors. This technique was principally developed to be applied in cases where it is difficult to use cumbersome instruments and to facilitate logistic management. The instruments to be employed are a digital camera and a grating. If the reflector surface is defective, the image of the grating, reflected on the solar collector, appears distorted. Analyzing the reflected image, we can obtain the local slope of the defective surface. These profilometric tests are useful to identify and monitor the mirror portions under mechanical stress and to estimate the losses caused by the light rays deflected outside the absorber.

  4. Describing Quadratic Cremer Point Polynomials by Parabolic Perturbations

    DEFF Research Database (Denmark)

    Sørensen, Dan Erik Krarup

    1996-01-01

    .Polynomials of the Cremer type correspond to parameters at the boundary of ahyperbolic component of the Mandelbrot set. In this paper we concentrate onthe main cardioid component. We investigate the differences between two-sided(i.e. alternating) and one-sided parabolic perturbations.In the two-sided case, we prove...... the existence of polynomials having an explicitlygiven external ray accumulating both at the Cremer point and at its non-periodicpreimage. We think of the Julia set as containing a "topologists double comb".In the one-sided case we prove a weaker result: the existence of polynomials havingan explicitly given...... external ray accumulating the Cremer point, but having in itsimpression both the Cremer point and its other preimage. We think of the Julia setas containing a "topologists single comb".By tuning, similar results hold on the boundary of any hyperbolic component of theMandelbrot set....

  5. Optimal Control of a Parabolic Equation with Dynamic Boundary Condition

    Energy Technology Data Exchange (ETDEWEB)

    Hoemberg, D., E-mail: hoemberg@wias-berlin.de; Krumbiegel, K., E-mail: krumbieg@wias-berlin.de [Weierstrass Institute for Applied Mathematics and Stochastics, Nonlinear Optimization and Inverse Problems (Germany); Rehberg, J., E-mail: rehberg@wias-berlin.de [Weierstrass Institute for Applied Mathematics and Stochastics, Partial Differential Equations (Germany)

    2013-02-15

    We investigate a control problem for the heat equation. The goal is to find an optimal heat transfer coefficient in the dynamic boundary condition such that a desired temperature distribution at the boundary is adhered. To this end we consider a function space setting in which the heat flux across the boundary is forced to be an L{sup p} function with respect to the surface measure, which in turn implies higher regularity for the time derivative of temperature. We show that the corresponding elliptic operator generates a strongly continuous semigroup of contractions and apply the concept of maximal parabolic regularity. This allows to show the existence of an optimal control and the derivation of necessary and sufficient optimality conditions.

  6. Generic parabolic points are isolated in positive characteristic

    Science.gov (United States)

    Lindahl, Karl-Olof; Rivera-Letelier, Juan

    2016-05-01

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

  7. Bilinear reduced order approximate model of parabolic distributed solar collectors

    KAUST Repository

    Elmetennani, Shahrazed

    2015-07-01

    This paper proposes a novel, low dimensional and accurate approximate model for the distributed parabolic solar collector, by means of a modified gaussian interpolation along the spatial domain. The proposed reduced model, taking the form of a low dimensional bilinear state representation, enables the reproduction of the heat transfer dynamics along the collector tube for system analysis. Moreover, presented as a reduced order bilinear state space model, the well established control theory for this class of systems can be applied. The approximation efficiency has been proven by several simulation tests, which have been performed considering parameters of the Acurex field with real external working conditions. Model accuracy has been evaluated by comparison to the analytical solution of the hyperbolic distributed model and its semi discretized approximation highlighting the benefits of using the proposed numerical scheme. Furthermore, model sensitivity to the different parameters of the gaussian interpolation has been studied.

  8. A semilinear parabolic system with a free boundary

    Science.gov (United States)

    Wang, Mingxin; Zhao, Yonggang

    2015-12-01

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

  9. Adaptive distributed parameter and input estimation in linear parabolic PDEs

    KAUST Repository

    Mechhoud, Sarra

    2016-01-01

    In this paper, we discuss the on-line estimation of distributed source term, diffusion, and reaction coefficients of a linear parabolic partial differential equation using both distributed and interior-point measurements. First, new sufficient identifiability conditions of the input and the parameter simultaneous estimation are stated. Then, by means of Lyapunov-based design, an adaptive estimator is derived in the infinite-dimensional framework. It consists of a state observer and gradient-based parameter and input adaptation laws. The parameter convergence depends on the plant signal richness assumption, whereas the state convergence is established using a Lyapunov approach. The results of the paper are illustrated by simulation on tokamak plasma heat transport model using simulated data.

  10. The parabolic Anderson model random walk in random potential

    CERN Document Server

    König, Wolfgang

    2016-01-01

    This is a comprehensive survey on the research on the parabolic Anderson model – the heat equation with random potential or the random walk in random potential – of the years 1990 – 2015. The investigation of this model requires a combination of tools from probability (large deviations, extreme-value theory, e.g.) and analysis (spectral theory for the Laplace operator with potential, variational analysis, e.g.). We explain the background, the applications, the questions and the connections with other models and formulate the most relevant results on the long-time behavior of the solution, like quenched and annealed asymptotics for the total mass, intermittency, confinement and concentration properties and mass flow. Furthermore, we explain the most successful proof methods and give a list of open research problems. Proofs are not detailed, but concisely outlined and commented; the formulations of some theorems are slightly simplified for better comprehension.

  11. Interpolation inequalities for weak solutions of nonlinear parabolic systems

    Directory of Open Access Journals (Sweden)

    Floridia Giuseppe

    2011-01-01

    Full Text Available Abstract The authors investigate differentiability of the solutions of nonlinear parabolic systems of order 2 m in divergence form of the following type ∑ | α | ≤ m ( - 1 | α | D α a α X , D u + ∂ u ∂ t = 0 . The achieved results are inspired by the paper of Marino and Maugeri 2008, and the methods there applied. This note can be viewed as a continuation of the study of regularity properties for solutions of systems started in Ragusa 2002, continued in Ragusa 2003 and Floridia and Ragusa 2012 and also as a generalization of the paper by Capanato and Cannarsa 1981, where regularity properties of the solutions of nonlinear elliptic systems with quadratic growth are reached. Mathematics Subject Classification (2000 Primary 35K41, 35K55. Secondary 35B65, 35B45, 35D10

  12. Darboux transformations and linear parabolic partial differential equations

    Energy Technology Data Exchange (ETDEWEB)

    Arrigo, Daniel J.; Hickling, Fred [Department of Mathematics, University of Central Arkansas, Conway, AR (United States)

    2002-07-19

    Solutions for a class of linear parabolic partial differential equation are provided. These solutions are obtained by first solving a system of (n+1) nonlinear partial differential equations. This system arises as the coefficients of a Darboux transformation and is equivalent to a matrix Burgers' equation. This matrix equation is solved using a generalized Hopf-Cole transformation. The solutions for the original equation are given in terms of solutions of the heat equation. These results are applied to the (1+1)-dimensional Schroedinger equation where all bound state solutions are obtained for a 2n-parameter family of potentials. As a special case, the solutions for integral members of the regular and modified Poeschl-Teller potentials are recovered. (author). Letter-to-the-editor.

  13. Strong Superconvergence of Finite Element Methods for Linear Parabolic Problems

    Directory of Open Access Journals (Sweden)

    Kening Wang

    2009-01-01

    Full Text Available We study the strong superconvergence of a semidiscrete finite element scheme for linear parabolic problems on =Ω×(0,], where Ω is a bounded domain in ℛ(≤4 with piecewise smooth boundary. We establish the global two order superconvergence results for the error between the approximate solution and the Ritz projection of the exact solution of our model problem in 1,(Ω and ( with 2≤<∞ and the almost two order superconvergence in 1,∞(Ω and ∞(. Results of the =∞ case are also included in two space dimensions (=1 or 2. By applying the interpolated postprocessing technique, similar results are also obtained on the error between the interpolation of the approximate solution and the exact solution.

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

    Energy Technology Data Exchange (ETDEWEB)

    Dudley, V.E. [EG and G MSI, Albuquerque, NM (United States); Evans, L.R.; Matthews, C.W. [Sandia National Labs., Albuquerque, NM (United States)

    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.

  15. Ray analysis of parabolic-index segmented planar waveguides.

    Science.gov (United States)

    Rastogi, V; Ghatak, A K; Ostrowsky, D B; Thyagarajan, K; Shenoy, M R

    1998-07-20

    A ray analysis of periodically segmented waveguides with parabolic-index variation in the high-index region is presented. We carried out the analysis using ray transfer matrices, which is convenient to implement and which can be extended to study different types of graded-index segmented waveguide. Results of this ray tracing approach clearly illustrate the waveguiding properties and the existence of stable and unstable regions of operation in segmented waveguides. We also illustrate the tapering action exhibited by segmented waveguides in which the duty cycle varies along the length of the waveguide. This analysis, although restricted to multimode structures, provides a clear visualization of the waveguiding properties in terms of ray propagation in segmented waveguides.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  18. Active matter in lateral parabolic confinement: From subdiffusion to superdiffusion

    Science.gov (United States)

    Ribeiro, H. E.; Potiguar, F. Q.

    2016-11-01

    In this work we studied the diffusive behavior of active brownian particles under lateral parabolic confinement. The results showed that we go from subdiffusion to ballistic motion as we vary the angular noise strength and confinement intensity. We argued that the subdiffusion regimes appear as consequence of the restricted space available for diffusion (achieved either through large confinement and/or large noise); we saw that when there are large confinement and noise intensity, a similar configuration to single file diffusion appears; on the other hand, normal and superdiffusive regimes may occur due to low noise (longer persistent motion), either through exploring a wider region around the potential minimum in the transverse direction (low confinement), or by forming independent clusters (high confinement).

  19. Workers intake too much salt from dishes of eating out and food service cafeterias; direct chemical analysis of sodium content.

    Science.gov (United States)

    Park, Hae-Ryun; Jeong, Gye-Ok; Lee, Seung-Lim; Kim, Jin-Young; Kang, Soon-Ah; Park, Kun-Young; Ryou, Hyun-Joo

    2009-01-01

    The average sodium intake of Koreans was reported to be 5,279.9 mg/day, which is one of the highest intake levels worldwide. The average Koreans intake 19.6% of sodium from kimchi, showing kimchi as the main contributor of sodium in this country (Ministry of Health and Welfare, 2005). The sodium content of dishes that are frequently chosen by workers, and which were served by foodservice cafeterias were chemically analyzed. The average sodium content of one meal provided by 10 foodservice cafeterias was 2,777.7 mg. Twenty-one, one-dish-meals, frequently chosen by workers for a lunch menu, were collected at 4 different restaurants for each menu by one male, aged in the twenties and analyzed chemically also. Workers who eat lunch at a workplace cafeteria everyday could intake about 8 g of salt at a one-time meal and those who eat out for a one-dish-meal would intake 3-8 g of salt without counting sodium content from the side dishes. From these study results, one could estimate that over 10 g of salt could be possible for a single meal for workers who eat out everyday. A nationwide nutrition campaign and education for low salt diets for restaurant owners and foodservice providers should be seriously considered.

  20. Effects of Modified Atmosphere Packaging, Food Life Extenders and Temperature on the Shelf Life of Ready-Made Dishes.

    Science.gov (United States)

    Sato, Jun; Maenishi, Takuya; Saito, Yuki; Masuda, Toshiro; Kadotani, Naoki; Kozakai, Hiroshi; Ito, Masanori

    2016-01-01

    The combined effect of several microbial control factors including gas barrier of containers, modified atmosphere packaging, food life extenders and storage temperature was discussed in order to determine the possibility for improving the shelf life for hamburger steak and deepfried chicken, representative ready-made dishes sold at convenience stores in Japan. Multiple measures including cold storage were effective in improving the shelf life of ready-made dishes. It was also suggested that storage tests for ready-made dishes should be conducted at 10℃, a practical temperature, to confirm the storable period, as well as at 15℃, an adequate abuse temperature, to confirm the effects of various microbial control factors. In the present study, the test group 4 (nitrogen + barrier containers + pH modifier) performed most favorably at both temperatures, indicating the efficacy of multiple means including "cold storage" in improving the shelf life (extending the consume-by date) of ready-made dishes. All strains isolated from the tested hamburger steak and deep-fried chicken were common food contaminant bacterial species.