Science.gov

Sample records for generator condensation experiments

  1. Steam generators, turbines, and condensers. Volume six

    SciTech Connect

    Not Available

    1986-01-01

    Volume six covers steam generators (How steam is generated, steam generation in a PWR, vertical U-tube steam generators, once-through steam generators, how much steam do steam generators make.), turbines (basic turbine principles, impulse turbines, reaction turbines, turbine stages, turbine arrangements, turbine steam flow, steam admission to turbines, turbine seals and supports, turbine oil system, generators), and condensers (need for condensers, basic condenser principles, condenser arrangements, heat transfer in condensers, air removal from condensers, circulating water system, heat loss to the circulating water system, factors affecting condenser performance, condenser auxiliaries).

  2. Flow Boiling and Condensation Experiment

    NASA Video Gallery

    The Flow Boiling and Condensation Experiment is another investigation that examines the flow of a mixture of liquids and the vapors they produce when in contact with hot space system equipment. Coo...

  3. Reactive Transport Modeling of Acid Gas Generation and Condensation

    SciTech Connect

    G. Zhahg; N. Spycher; E. Sonnenthal; C. Steefel

    2005-01-25

    Pulvirenti et al. (2004) recently conducted a laboratory evaporation/condensation experiment on a synthetic solution of primarily calcium chloride. This solution represents one potential type of evaporated pore water at Yucca Mountain, Nevada, a site proposed for geologic storage of high-level nuclear waste. These authors reported that boiling this solution to near dryness (a concentration factor >75,000 relative to actual pore waters) leads to the generation of acid condensate (pH 4.5) presumably due to volatilization of HCl (and minor HF and/or HNO{sub 3}). To investigate the various processes taking place, including boiling, gas transport, and condensation, their experiment was simulated by modifying an existing multicomponent and multiphase reactive transport code (TOUGHREACT). This code was extended with a Pitzer ion-interaction model to deal with high ionic strength. The model of the experiment was set-up to capture the observed increase in boiling temperature (143 C at {approx}1 bar) resulting from high concentrations of dissolved salts (up to 8 m CaCl{sub 2}). The computed HCI fugacity ({approx} 10{sup -4} bars) generated by boiling under these conditions is not sufficient to lower the pH of the condensate (cooled to 80 and 25 C) down to observed values unless the H{sub 2}O mass fraction in gas is reduced below {approx}10%. This is because the condensate becomes progressively diluted by H{sub 2}O gas condensation. However, when the system is modeled to remove water vapor, the computed pH of instantaneous condensates decreases to {approx}1.7, consistent with the experiment (Figure 1). The results also show that the HCl fugacity increases, and calcite, gypsum, sylvite, halite, MgCl{sub 2}4H{sub 2}O and CaCl{sub 2} precipitate sequentially with increasing concentration factors.

  4. 33. TURBINE HALL, ORIGINAL TURBO GENERATOR, INTACT CONDENSER Philadelphia ...

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

    33. TURBINE HALL, ORIGINAL TURBO GENERATOR, INTACT CONDENSER - Philadelphia Electric Company, Richmond Power Station, Southeast end of Lewis Street along Delaware River, Philadelphia, Philadelphia County, PA

  5. 2. VIEW NORTHEAST OF CONDENSER WATER INTAKE (LEFT), GENERATING PLANT ...

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

    2. VIEW NORTHEAST OF CONDENSER WATER INTAKE (LEFT), GENERATING PLANT AND STACK (CENTER), AND VIADUCT (EXTREME RIGHT) - Turners Falls Power & Electric Company, Hampden Station, East bank of Connecticut River, Chicopee, Hampden County, MA

  6. 32. TURBINE HALL, ORIGINAL TURBO GENERATOR, DETAILS AT CONDENSER, LOOKING ...

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

    32. TURBINE HALL, ORIGINAL TURBO GENERATOR, DETAILS AT CONDENSER, LOOKING SOUTHEAST - Philadelphia Electric Company, Richmond Power Station, Southeast end of Lewis Street along Delaware River, Philadelphia, Philadelphia County, PA

  7. 31. TURBINE HALL, ORIGINAL TURBO GENERATOR, DETAILS AT CONDENSER, LOOKING ...

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

    31. TURBINE HALL, ORIGINAL TURBO GENERATOR, DETAILS AT CONDENSER, LOOKING SOUTHEAST - Philadelphia Electric Company, Richmond Power Station, Southeast end of Lewis Street along Delaware River, Philadelphia, Philadelphia County, PA

  8. Next generation interatomic potentials for condensed systems

    NASA Astrophysics Data System (ADS)

    Handley, Christopher Michael; Behler, Jörg

    2014-07-01

    The computer simulation of condensed systems is a challenging task. While electronic structure methods like density-functional theory (DFT) usually provide a good compromise between accuracy and efficiency, they are computationally very demanding and thus applicable only to systems containing up to a few hundred atoms. Unfortunately, many interesting problems require simulations to be performed on much larger systems involving thousands of atoms or more. Consequently, more efficient methods are urgently needed, and a lot of effort has been spent on the development of a large variety of potentials enabling simulations with significantly extended time and length scales. Most commonly, these potentials are based on physically motivated functional forms and thus perform very well for the applications they have been designed for. On the other hand, they are often highly system-specific and thus cannot easily be transferred from one system to another. Moreover, their numerical accuracy is restricted by the intrinsic limitations of the imposed functional forms. In recent years, several novel types of potentials have emerged, which are not based on physical considerations. Instead, they aim to reproduce a set of reference electronic structure data as accurately as possible by using very general and flexible functional forms. In this review we will survey a number of these methods. While they differ in the choice of the employed mathematical functions, they all have in common that they provide high-quality potential-energy surfaces, while the efficiency is comparable to conventional empirical potentials. It has been demonstrated that in many cases these potentials now offer a very interesting new approach to study complex systems with hitherto unreached accuracy.

  9. Oblique solitons generated by the flow of a polariton condensate past an obstacle

    SciTech Connect

    Kamchatnov, A. M. Korneev, S. V.

    2012-10-15

    The formation of oblique solitons in a polariton condensate flowing past an obstacle is considered. Because of the finite lifetime of polaritons, the condensate flow is inhomogeneous, which leads to a significant modification of the conditions necessary for the generation of oblique solitons as compared to the conditions established earlier for the flow of an atomic condensate. In particular, it is established that oblique solitons in the polariton case can be generated by a subsonic flow of the condensate in agreement with the results of recent experiments [9]. The geometric shape and other parameters of oblique solitons are analytically calculated using a model based on the nonlinear Schroedinger equation with damping, and the analytical results are confirmed by numerical simulations.

  10. Pion condensation and instabilities: current theory and experiment

    SciTech Connect

    Gyulassy, M.

    1980-05-01

    Current calculations of pion condensation phenomena in symmetric nuclear matter are reviewed. The RPA and MFA methods are compared. Latest results (LBL-10572) with a relativistic MFA theory constrained by bulk nuclear properties are presented. The differences between equilibrium (condensation) and nonequilibrium (dynamic) instabilities are discussed. Finally, two-proton correlation experiments aimed at looking for critical scattering phenomena and two-pion correlation experiments aimed at looking for pion field coherence are analyzed. 10 figures, 2 tables.

  11. Experiments on condensation over in-line and staggered condenser tubes in the presence of non-condensable gases

    NASA Astrophysics Data System (ADS)

    Ramadan, Abdulghani; Yamali, Cemil

    2013-12-01

    The problem of the forced film condensation heat transfer of pure steam and steam-air mixture flowing downward a tier of horizontal cylinders is investigated experimentally. An experimental setup was manufactured and mounted at Middle East Technical University workshop. A set of experiments were conducted to observe the condensation heat transfer phenomenon and to verify the theoretical results. The results of the experimental investigation are presented to show the effect of different parameters on the film condensation heat transfer phenomenon over bundle of tubes. These parameters include; free stream velocity, free stream non-condensable gas (air) mass fractions, free stream temperature to wall temperature difference, the angle of inclination. heat transfer coefficients are evaluated at different working conditions for both inline and staggered arrangements. Results show that; a remarked reduction in the vapor side heat transfer coefficient is noticed when very small amounts of air mass fractions present in the vapor. In addition, it decreases by increasing the temperature difference. On the other hand, it increases by increasing the free stream velocity (Reynolds number). Average heat transfer coefficient at the middle and the bottom cylinders increases by increasing the angle of inclination, whereas, no significant change is observed for that of the upper cylinder. Although some discrepancies are noticed, the present study results are inline and in a reasonable agreement with the theory and experiment in the literature.

  12. Experiments and Modeling of Evaporating/Condensing Menisci

    NASA Technical Reports Server (NTRS)

    Plawsky, Joel; Wayner, Peter C., Jr.

    2013-01-01

    Discuss the Constrained Vapor Bubble (CVB) experiment and how it aims to achieve a better understanding of the physics of evaporation and condensation and how they affect cooling processes in microgravity using a remotely controlled microscope and a small cooling device.

  13. High gliding fluid power generation system with fluid component separation and multiple condensers

    SciTech Connect

    Mahmoud, Ahmad M; Lee, Jaeseon; Radcliff, Thomas D

    2014-10-14

    An example power generation system includes a vapor generator, a turbine, a separator and a pump. In the separator, the multiple components of the working fluid are separated from each other and sent to separate condensers. Each of the separate condensers is configured for condensing a single component of the working fluid. Once each of the components condense back into a liquid form they are recombined and exhausted to a pump that in turn drives the working fluid back to the vapor generator.

  14. Bose-Einstein Condensation: A Platform for Quantum Simulation Experiments

    NASA Astrophysics Data System (ADS)

    Yamamoto, Yoshihisa; Takahashi, Yoshiro

    Bose-Einstein condensation (BEC) of dilute atomic gases and dense exciton-polaritons provides unique experimental platforms for the simulation of quantum many-body systems in various trap and lattice structures. Atomic BEC is suitable for exploration of the thermal equilibrium and steady state properties of isolated many-body systems, while exciton-polariton BEC is suitable for study of the nonequilibrium and transient properties of open dissipative many-body systems. In this chapter, we will review the fundamental properties of these distinct Bose-Einstein condensates to provide a basis for later discussions of various quantum simulation experiments using cold atoms and exciton-polaritons.

  15. An experimental study of a VVER reactor's steam generator model operating in the condensing mode

    NASA Astrophysics Data System (ADS)

    Morozov, A. V.; Remizov, O. V.

    2012-05-01

    Results obtained from an experimental study of a VVER reactor's steam generator model operating in the condensing mode are presented. The obtained empirical dependence for calculating the power of heat exchangers operating in the steam condensation mode is presented.

  16. Generation of the Higgs condensate and its decay after inflation

    SciTech Connect

    Enqvist, Kari; Meriniemi, Tuukka; Nurmi, Sami E-mail: tuukka.meriniemi@helsinki.fi

    2013-10-01

    We investigate the dynamics of the Standard Model higgs with a minimal coupling to gravity during and after inflation. In the regime where the Standard Model vacuum is stable, we find that the higgs becomes a light spectator field after about 30 efolds of inflation, irrespectively of its initial value. Once the higgs has become light, its root-mean-square value h{sub *} relaxes to equilibrium in about 85 efolds for the inflationary scale of H{sub *} = 10{sup 4} GeV and in 20 efolds for H{sub *} = 10{sup 10} GeV. The equilibrium value is given by h{sub *} ∼ 0.36λ{sub *}{sup −1/4}H{sub *}, where λ{sub *} = 0.09...0.0005 is the higgs self coupling at the scales H{sub *} = 10{sup 4}...10{sup 10} GeV. We show that the main decay channel of the higgs condensate after inflation is the resonant production of Standard Model gauge bosons. For a set of parameters we find that a significant part of the condensate has decayed in between 340 and 630 Hubble times after the onset of higgs oscillations, depending on H{sub *} in a non-trivial way. The higgs perturbations correspond to isocurvature modes during inflation but they could generate significant adiabatic perturbations at a later stage for example through a modulation of the reheating stage. However, this requires that the inflaton(s) decay no later than a few hundred Hubble times after the onset of higgs oscillations.

  17. Undoped GaAs bilayers for exciton condensation experiments

    NASA Astrophysics Data System (ADS)

    Lilly, M. P.

    2005-03-01

    Experimental progress in transport studies of exciton condensation of in electron and hole bilayers at high magnetic fields [1,2] has shown this novel physics can be observed. Fabrication of the bipolar electron-hole bilayers for zero field studies of exciton condensation still remains elusive. We describe a series of experiments on undoped GaAs/AlGaAs heterostructures with the motivation of making electron-hole bilayers. In these undoped devices, external electric fields induce carriers rather than the traditional doping techniques. Single layer electron (or hole) devices demonstrate a high mobility over a wide range of density. More recently, fully undoped bilayers have been made where the density in each layer is independently controlled with gates on the top and bottom of the bilayer. In this talk we present high field transport of undoped electron-electron bilayers, and describe recent progress towards extending the fabrication techniques to creating electron-hole bilayers for exciton condensation studies at zero magnetic field. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000. 1. M. Kellogg, J. P. Eisenstein, L. N. Pfeiffer, and K. W. West, Phys. Rev. Lett. 93 036801 (2004). 2. E. Tutoc, M. Shayegan, and D. A. Huse, Phys. Rev. Lett. 93, 036802 (2004).

  18. Condensation during gravity driven ECC: Experiments with PACTEL

    SciTech Connect

    Munther, R.; Kalli, H.; Kouhia, J.

    1995-09-01

    This paper provides the results of the second series of gravity driven emergency core cooling (ECC) experiments with PACTEL (Parallel Channel Test Loop). The simulated accident was a small break loss-of-coolant accident (SBLOCA) with a break in a cold leg. The ECC flow was provided from a core makeup tank (CMT) located at a higher elevation than the main part of the primary system. The CMT was pressurized with pipings from the pressurizer and a cold leg. The tests indicated that steam condensation in the CMT can prevent ECC and lead to core uncovery.

  19. Refractory residues, condensates and chondrules from solar furnace experiments

    NASA Technical Reports Server (NTRS)

    King, E. A.

    1982-01-01

    Vertical access solar furnace experiments have produced refractory residues, condensates and chondrules that are similar to components of chondritic meteorites. In particular, Ca-Al-rich refractory residues similar in chemistry to inclusions in carbonaceous chondrites have been produced by partial evaporation of basaltic bulk rock samples. Fe-Mg-Si-rich condensates with distinctive microbotryoidal morphology have been collected from the same sample runs. Particle coatings and aggregates with virtually identical microbotryoidal morphology and major element chemistry have been identified in both the Allende and Murchison meteorites. Spattered drops from melt beads undergoing heating and partial evaporation resemble some meteoritic chondrules in their mineralogies, textures, grain size, and sorting. The spatter mechanism is highly efficient in the production of chondrules. If any of the refractory inclusions in chondrites are, in fact, partial evaporation residues, many meteoritic fluid drop chondrules must have been formed by this process. The hot central portion of the solar nebula, acting on a cloud of dust and gas, is the probable source of heat required to produce the fractionated chemistry and physical state of many of the components of chondritic meteorites.

  20. Development and Capabilities of ISS Flow Boiling and Condensation Experiment

    NASA Technical Reports Server (NTRS)

    Nahra, Henry; Hasan, Mohammad; Balasubramaniam, R.; Patania, Michelle; Hall, Nancy; Wagner, James; Mackey, Jeffrey; Frankenfield, Bruce; Hauser, Daniel; Harpster, George; Nawrocki, David; Clapper, Randy; Kolacz, John; Butcher, Robert; May, Rochelle; Chao, David; Mudawar, Issam; Kharangate, Chirag R.; O'Neill, Lucas E.

    2015-01-01

    An experimental facility to perform flow boiling and condensation experiments in long duration microgravity environment is being designed for operation on the International Space Station (ISS). This work describes the design of the subsystems of the FBCE including the Fluid subsystem modules, data acquisition, controls, and diagnostics. Subsystems and components are designed within the constraints of the ISS Fluid Integrated Rack in terms of power availability, cooling capability, mass and volume, and most importantly the safety requirements. In this work we present the results of ground-based performance testing of the FBCE subsystem modules and test module which consist of the two condensation modules and the flow boiling module. During this testing, we evaluated the pressure drop profile across different components of the fluid subsystem, heater performance, on-orbit degassing subsystem, heat loss from different modules and components, and performance of the test modules. These results will be used in the refinement of the flight system design and build-up of the FBCE which is manifested for flight in late 2017-early 2018.

  1. Recent experiments with ring Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Eckel, S.; Kumar, A.; Anderson, N. W.; Campbell, G. K.

    2016-05-01

    Here, we present three recent results of our experiments with ring-shaped 23 Na Bose-Einstein condensates. First, we present results of the effect of temperature on the decay of persistent currents in the presence of a local, stationary perturbation, or weak link. When the weak link rotates, it can drive transitions between quantized persistent current states in the ring, that form hysteresis loops whose size depends strongly on temperature. We find that our data does not fit with a simple model of thermal activation. Second, we present a new method to measure the quantized persistent current state of the ring in a minimally-destructive way. This technique uses phonons as probes of the background flow through the Doppler effect. Finally, we present a set of experiments designed to reproduce the horizon problem in the early universe. Supersonic expansion of the ring creates causally-disconnected regions of BEC whose phase evolves at different rates. When the expansion stops and these regions are allowed to recombine, they form topological excitations. These excitations can be predicted using a simple theory that shows excellent agreement with the data.

  2. Expressing death risk as condensed life experience and death intensity.

    PubMed

    Ioannidis, John P A

    2013-08-01

    Some risk exposures, including many medical and surgical procedures, typically carry hazards of death that are difficult to convey and appreciate in absolute terms. I propose presenting the death risk as a condensed life experience (i.e., the equivalent amount of life T that would carry the same cumulative mortality hazard for a person of the same age and sex based on life tables). For example, if the risk of death during an elective 1-hour procedure is 0.01%, and same-age and same-sex people have a 0.01% death risk over 1 month, one can inform the patient that "this procedure carries the same death risk as living 1 month of normal life." Comparative standards from other risky activities or from a person with the same disease at the same stage and same predictive profile could also be used. A complementary metric that may be useful to consider is the death intensity. The death intensity λ is the hazard function that shows the fold-risk estimate of dying compared with the reference person. The death intensity can vary substantially for different phases of the event, operation, or procedure (e.g., intraoperative, early postoperative, late postoperative), and this variability may also be useful to convey. T will vary depending on the time window for which it is computed. I present examples for calculating T and λ using literature data on accidents, ascent to Mount Everest, and medical and surgical procedures. PMID:23579043

  3. The first experiments with Bose-Einstein condensation of rubidium-87

    NASA Astrophysics Data System (ADS)

    Ensher, Jason Remington

    1999-10-01

    Bose-Einstein Condensation (BEC) is the macroscopic occupation of the ground-state of a system of bosons that occurs when the extent of the wavefunctions of the particles is comparable to the interparticle spacing. Although predicted by Albert Einstein in 1924) BEC in a dilute system was observed only recently in an atomic vapor of 87Rb by our group in 1995. This thesis describes the first experiments to explore the properties of this new state of matter. In early experiments, we studied how interparticle interactions modify the ground-state wavefunction and mean energy. We observed phonon-like collective excitations of the condensate. We studied modes of different angular momenta and energies. Our observations of how the characteristics of the modes depend on interactions quantitatively supported the mean- field picture of the dilute BEC. Shortly thereafter, we developed thermometry and calorimetry to study the ground-state fraction and mean energy of the Bose gas as a function of temperature. The BEC transition temperature and the temperature dependence of the ground-state fraction are in good agreement with predictions for an ideal Bose gas. However, the measured mean energy is larger than that of the ideal gas below the transition. We observe a distinct change in the energy-temperature curve near the transition, which indicates a sharp feature in the specific heat. In an effort to produce larger condensates we constructed a double-MOT apparatus that became the third-generation machine at JILA to observe and study BEC. The new apparatus produces condensates five times more quickly than the original experiment, increasing the number of atoms in the condensate from several thousand to 1-2 million atoms. Using the improved apparatus, we studied the TOP (time-averaged orbiting potential) magnetic trap. An important, new observation is that the trap symmetry is affected by the sag due to gravity, an effect which can be exploited to create very harmonic, spherical

  4. Recent multiwave Cherenkov generator experiments

    SciTech Connect

    Adler, R.; Richter-Sand, R.; Hacker, F.; Walsh, J.; Arman, M.

    1994-12-31

    The initial operating characteristics of the North Star Research Corporation (NSRC) multiwave generator experiment are discussed. The first radiation from the NSRC apparatus has now been observed and the immediate goal is to optimize the power output by providing a beam which is better matched to the field profile (a thinner beam propagating closer to the vanes). When this has been accomplished a detailed comparison of the performance of MWCG/MWDG (multiwave diffraction generator/multiwave Cherenkov generator) structures with BWO structures of the same interaction length will be undertaken.

  5. Oblique half-solitons and their generation in exciton-polariton condensates

    SciTech Connect

    Flayac, H.; Solnyshkov, D. D.; Malpuech, G.

    2011-05-15

    We describe oblique half-solitons, a new type of topological defects in a two-dimensional spinor Bose-Einstein condensate. A realistic protocol based on the optical spin Hall effect is proposed toward their generation within an exciton-polariton system.

  6. A DEMONSTRATION OF BENEFICIAL USES OF WARM WATER FROM CONDENSERS OF ELECTRIC GENERATING PLANTS

    EPA Science Inventory

    The report gives results of a project to demonstrate that warmed cooling water from condensers of electric generating plants can effectively and economically heat greenhouses. The 0.2-hectare demonstration greenhouse, at Northern States Power Co.'s Sherburne County (Sherco) Gener...

  7. Investigations in the problem of pion condensation using generator co-ordinate methods

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, P.; Da Providencia, J.

    1981-11-01

    Pion condensation in neutron matter has been investigated using the generator coordinate method and a simple p-wave interaction. The assumption of a condensed mode corresponding to one pion momentum (determined variationally) helps evaluate all the necessary matrix elements exactly. The technique of charge projection from a coherent state of negative pions is discussed, and calculations have been carried out for the cases of average charge conservation, charge projection before variation and for a charge conserving trial function. The ground-state energies and the lowest excitations of the system are obtained from numerical solutions of the Hill-Wheeler equation.

  8. The Next Generation BLAST Experiment

    NASA Astrophysics Data System (ADS)

    Galitzki, Nicholas; Ade, Peter A. R.; Angilè, Francesco E.; Ashton, Peter; Beall, James A.; Becker, Dan; Bradford, Kristi J.; Che, George; Cho, Hsiao-Mei; Devlin, Mark J.; Dober, Bradley J.; Fissel, Laura M.; Fukui, Yasuo; Gao, Jiansong; Groppi, Christopher E.; Hillbrand, Seth; Hilton, Gene C.; Hubmayr, Johannes; Irwin, Kent D.; Klein, Jeffrey; van Lanen, Jeff; Li, Dale; Li, Zhi-Yun; Lourie, Nathan P.; Mani, Hamdi; Martin, Peter G.; Mauskopf, Philip; Nakamura, Fumitaka; Novak, Giles; Pappas, David P.; Pascale, Enzo; Pisano, Giampaolo; Santos, Fabio P.; Savini, Giorgio; Scott, Douglas; Stanchfield, Sara; Tucker, Carole; Ullom, Joel N.; Underhill, Matthew; Vissers, Michael R.; Ward-Thompson, Derek

    The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) was a suborbital experiment designed to map magnetic fields in order to study their role in star formation processes. BLASTPol made detailed polarization maps of a number of molecular clouds during its successful flights from Antarctica in 2010 and 2012. We present the next-generation BLASTPol instrument (BLAST-TNG) that will build off the success of the previous experiment and continue its role as a unique instrument and a test bed for new technologies. With a 16-fold increase in mapping speed, BLAST-TNG will make larger and deeper maps. Major improvements include a 2.5-m carbon fiber mirror that is 40% wider than the BLASTPol mirror and 3000 polarization sensitive detectors. BLAST-TNG will observe in three bands at 250, 350, and 500 μm. The telescope will serve as a pathfinder project for microwave kinetic inductance detector (MKID) technology, as applied to feedhorn-coupled submillimeter detector arrays. The liquid helium cooled cryostat will have a 28-day hold time and will utilize a closed-cycle 3He refrigerator to cool the detector arrays to 270 mK. This will enable a detailed mapping of more targets with higher polarization resolution than any other submillimeter experiment to date. BLAST-TNG will also be the first balloon-borne telescope to offer shared risk observing time to the community. This paper outlines the motivation for the project and the instrumental design.

  9. WIPP Gas-Generation Experiments

    SciTech Connect

    Frank S. Felicione; Steven M. Frank; Dennis D. Keiser

    2007-05-01

    An experimental investigation was conducted for gas generation in contact-handled transuranic (CH TRU) wastes subjected for several years to conditions similar to those expected to occur at the Waste Isolation Pilot Plant (WIPP) should the repository eventually become inundated with brine. Various types of actual CH TRU wastes were placed into 12 corrosion-resistant vessels. The vessels were loosely filled with the wastes, which were submerged in synthetic brine having the same chemical composition as that in the WIPP vicinity. The vessels were also inoculated with microbes found in the Salado Formation at WIPP. The vessels were sealed, purged, and the approximately 750 ml headspace in each vessel was pressurized with nitrogen gas to approximately 146 atmospheres to create anoxic conditions at the lithostatic pressure estimated in the repository were it to be inundated. The temperature was maintained at the expected 30°C. The test program objective was to measure the quantities and species of gases generated by metal corrosion, radiolysis, and microbial activity. These data will assist in the specification of the rates at which gases are produced under inundated repository conditions for use in the WIPP Performance Assessment computer models. These experiments were very carefully designed, constructed, instrumented, and performed. Approximately 6 1/2 years of continuous, undisturbed testing were accumulated. Several of the vessels showed significantly elevated levels of generated gases, virtually all of which was hydrogen. Up to 4.2% hydrogen, by volume, was measured. Only small quantities of other gases, principally carbon dioxide, were detected. Gas generation was found to depend strongly on the waste composition. The maximum hydrogen generation occurred in vessels containing carbon steel. Visual examination of carbon-steel coupons confirmed the correspondence between the extent of observable corrosion and hydrogen generation. Average corrosion penetration rates

  10. Generation of massive entanglement through an adiabatic quantum phase transition in a spinor condensate.

    PubMed

    Zhang, Z; Duan, L-M

    2013-11-01

    We propose a method to generate massive entanglement in a spinor Bose-Einstein condensate from an initial product state through an adiabatic sweep of the magnetic field across a quantum phase transition induced by competition between the spin-dependent collision interaction and the quadratic Zeeman effect. The generated many-body entanglement is characterized by the experimentally measurable entanglement depth in the proximity of the Dicke state. We show that the scheme is robust to practical noise and experimental imperfection and under realistic conditions it is possible to generate genuine entanglement for hundreds of atoms. PMID:24237490

  11. Generation of ultrafast optical fiducials for shock-wave experiments

    NASA Astrophysics Data System (ADS)

    Dodson, B. W.

    Recent advances in high time resolution optical diagnostic instrumentation for shock wave experiments in condensed media (especially timing resolved spectroscopy) have resulted in new challenges concerning the timing of such experiments. A technique for detecting the presence of a shock wave through the generation of an optical fiducial signal, which is detected and recorded directly by the optical recording device (typically a streak camera) is presented. This technique, which is based on Stress Induced Defeat of Total Internal Reflection (SIDTIR), requires only simple apparatus and set up, and offers fiducial transition times as short as 50 psec in a reasonable experimental configuration.

  12. Mesh generation and energy group condensation studies for the jaguar deterministic transport code

    SciTech Connect

    Kennedy, R. A.; Watson, A. M.; Iwueke, C. I.; Edwards, E. J.

    2012-07-01

    The deterministic transport code Jaguar is introduced, and the modeling process for Jaguar is demonstrated using a two-dimensional assembly model of the Hoogenboom-Martin Performance Benchmark Problem. This single assembly model is being used to test and analyze optimal modeling methodologies and techniques for Jaguar. This paper focuses on spatial mesh generation and energy condensation techniques. In this summary, the models and processes are defined as well as thermal flux solution comparisons with the Monte Carlo code MC21. (authors)

  13. Study to perform preliminary experiments to evaluate particle generation and characterization techniques for zero-gravity cloud physics experiments

    NASA Technical Reports Server (NTRS)

    Katz, U.

    1982-01-01

    Methods of particle generation and characterization with regard to their applicability for experiments requiring cloud condensation nuclei (CCN) of specified properties were investigated. Since aerosol characterization is a prerequisite to assessing performance of particle generation equipment, techniques for characterizing aerosol were evaluated. Aerosol generation is discussed, and atomizer and photolytic generators including preparation of hydrosols (used with atomizers) and the evaluation of a flight version of an atomizer are studied.

  14. (X-ray diffraction experiments with condenser matter)

    SciTech Connect

    Coppens, P.

    1990-01-01

    This report discusses research on the following topics: high-{Tc} superconductors; The response of crystal to an applied electric field; quasicrystals; surface structure and kinetics of surface layer formation; EXAFS studies of superconductors and heterostructures; effect of iron on the crystal structure of perovskite; x-ray detector development; and SAXS experiments. (LSP)

  15. Experiment and analysis of ablation and condensation in NIF first wall materials

    SciTech Connect

    Jin, H.; Peterson, P.F.; Turner, R.E.; Anderson, A.T.

    1996-06-14

    Experiments were performed on Nova at Lawrence Livermore National Laboratory to study the ablation and condensation process of National Ignition Facility (NIF) first wall materials. Plates of candidate first wall materials (SiO{sub 2}, B{sub 4}, and Al{sub 2}O{sub 3}) were exposed to x-rays from hohlraums in the Nova chamber. Ablated material was collected and measured on a receiving plate which was blocked form direct x-ray exposure. This article presents the results form these experiments and comparisons with predictions from numerical simulations The net condensation flux was calculated using the TSUNAMI code, which was modified to incorporate the feature of condensation boundaries.

  16. Bose-Einstein Condensates in Optical Lattices: Experiments

    NASA Astrophysics Data System (ADS)

    Morsch, O.

    In the early days of laser cooling, which together with magnetic trapping techniques led to the first observation of BEC in 1995, it was realized that the optical interference between the cooling beams could lead to a spatially periodic density modulation of the trapped atoms. This notion of a "three-dimensional egg-carton" for cold atoms quickly led to a number of experiments confirming the existence of such a light-bound crystal and exploring its properties [1-3]. It was found that, indeed, cold atoms could be trapped in such periodic structures, and it was possible to measure, for example, the quantized motion of the atoms inside the potential wells. While early experiments were carried out in the dissipative regime using near-resonant lattices in which the atoms were continuously cooled through the Sisyphus mechanism involving light scattering [4], more sophisticated experimental techniques later enabled studies on far-detuned lattices in which atoms evolved coherently.

  17. Sculpting quasi-one-dimensional Bose-Einstein condensate to generate calibrated matter waves

    NASA Astrophysics Data System (ADS)

    Akram, Javed; Pelster, Axel

    2016-02-01

    We explore theoretically how to tune the dynamics of a quasi-one-dimensional harmonically trapped Bose-Einstein condensate (BEC) due to an additional red- and blue-detuned Hermite-Gaussian dimple trap (HGdT). To this end we study a BEC in a highly nonequilibrium state, which is not possible in a traditional harmonically confined trap. Our system is modeled by a time-dependent Gross-Pitaevskii equation, which is numerically solved by the Crank-Nicolson method in both imaginary and real time. For equilibrium, we obtain a condensate with two bumps or dips which are induced by the chosen TEM01 mode for the red- or blue-detuned HGdT, respectively. Afterward, in time-of-flight dynamics, we examine the adherence or decay of the two bumps or dips in the condensate, which are induced by the still present red- or blue-detuned HGdT, respectively. On the other hand, once the red or blue HGdT potential is switched off, shock waves or bi-trains of gray or dark pair-solitons are created. During this process it is found that the generation of gray or dark pair-soliton bi-trains are generic phenomena of collisions of moderately or fully fragmented BEC. Additionally, it turns out that the special shape of generated solitons in the harmonically trapped BEC firmly depends upon the geometry of the HGdT.

  18. Intermolecular forces between low generation PAMAM dendrimer condensed DNA helices: role of cation architecture.

    PubMed

    An, Min; Parkin, Sean R; DeRouchey, Jason E

    2014-01-28

    In recent years, dendriplexes, complexes of cationic dendrimers with DNA, have become attractive DNA delivery vehicles due to their well-defined chemistries. To better understand the nature of the forces condensing dendriplexes, we studied low generation poly(amidoamine) (PAMAM) dendrimer-DNA complexes and compared them to comparably charged linear arginine peptides. Using osmotic stress coupled with X-ray scattering, we have investigated the effect of molecular chain architecture on DNA-DNA intermolecular forces that determine the net attraction and equilibrium interhelical distance within these polycation condensed DNA arrays. In order to compact DNA, linear cations are believed to bind in DNA grooves and to interact with the phosphate backbone of apposing helices. We have previously shown a length dependent attraction resulting in higher packaging densities with increasing charge for linear cations. Hyperbranched polycations, such as polycationic dendrimers, presumably would not be able to bind to DNA and correlate their charges in the same manner as linear cations. We show that attractive and repulsive force amplitudes in PAMAM-DNA assemblies display significantly different trends than comparably charged linear arginines resulting in lower DNA packaging densities with increasing PAMAM generation. The salt and pH dependencies of packaging in PAMAM dendrimer-DNA and linear arginine-DNA complexes were also investigated. Significant differences in the force curve behaviour and salt and pH sensitivities suggest that different binding modes may be present in DNA condensed by dendrimers when compared to linear polycations. PMID:24651934

  19. MELCOR 1.8.1 assessment: PNL Ice Condenser Aerosol Experiments

    SciTech Connect

    Gross, R.J.

    1993-06-01

    The MELCOR code was used to simulate PNL`s Ice Condenser Experiments 11-6 and 16-11. In these experiments, ZnS was injected into a mixing chamber, and the combined steam/air/aerosol mixture flowed into an ice condenser which was l4.7m tall. Experiment 11-6 was a low flow test; Experiment l6-1l was a high flow test. Temperatures in the ice condenser region and particle retention were measured in these tests. MELCOR predictions compared very well to the experimental data. The MELCOR calculations were also compared to CONTAIN code calculations for the same tests. A number of sensitivity studies were performed. It as found that simulation time step, aerosol parameters such as the number of MAEROS components and sections used and the particle density, and ice condenser parameters such as the energy capacity of the ice, ice heat transfer coefficient multiplier, and ice heat structure characteristic length all could affect the results. Thermal/hydraulic parameters such as control volume equilibrium assumptions, flow loss coefficients, and the bubble rise model were found to affect the results less significantly. MELCOR results were not machine dependent for this problem.

  20. Generation of monodisperse droplets by spontaneous condensation of flow in nozzles

    NASA Technical Reports Server (NTRS)

    Lai, Der-Shaiun; Kadambi, J. R.

    1993-01-01

    Submicron size monodisperse particles are of interest in many industrial and scientific applications. These include the manufacture of ceramic parts using fine ceramic particles, the production of thin films by deposition of ionized clusters, monodisperse seed particles for laser anemometry, and the study of size dependence of cluster chemical and physical properties. An inexpensive and relatively easy way to generate such particles is by utilizing the phenomenon of spontaneous condensation. The phenomenon occurs when the vapor or a mixture of a vapor and a noncondensing gas is expanded at a high expansion rate. The saturation line is crossed with the supercooled vapor behaving like a gas, until all of a sudden at the so called Wilson point, condensation occurs, resulting in a large number of relatively monodisperse droplets. The droplet size is a function of the expansion rate, inlet conditions, mass fraction of vapor, gas properties, etc. Spontaneous condensation of steam and water vapor and air mixture in a one dimensional nozzle was modeled and the resulting equations solved numerically. The droplet size distribution at the exit of various one dimensional nozzles and the flow characteristics such as pressure ratio, mean droplet radius, vapor and droplet temperatures, nucleation flux, supercooling, wetness, etc., along the axial distance were obtained. The numerical results compared very well with the available experimental data. The effect of inlet conditions, nozzle expansion rates, and vapor mass fractions on droplet mean radius, droplet size distribution, and pressure ratio were examined.

  1. Dynamical generation of phase-squeezed states in two-component Bose-Einstein condensates

    SciTech Connect

    Jin, G. R.; An, Y.; Yan, T.; Lu, Z. S.

    2010-12-15

    As an ''input'' state of a linear (Mach-Zehnder or Ramsey) interferometer, the phase-squeezed state proposed by Berry and Wiseman exhibits the best sensitivity approaching to the Heisenberg limit [Phys. Rev. Lett. 85, 5098 (2000)]. Similar with the Berry and Wiseman's state, we find that two kinds of phase-squeezed states can be generated dynamically with atomic Bose-Einstein condensates confined in a symmetric double-well potential, which shows squeezing along spin operator S{sub y} and antisqueezing along S{sub z}, leading to subshot-noise phase estimation.

  2. Simple method for generating Bose-Einstein condensates in a weak hybrid trap

    SciTech Connect

    Zaiser, M.; Hartwig, J.; Schlippert, D.; Velte, U.; Winter, N.; Lebedev, V.; Ertmer, W.; Rasel, E. M.

    2011-03-15

    We report on a simple trapping scheme for the generation of Bose-Einstein condensates of {sup 87}Rb atoms. This scheme employs a near-infrared single-beam optical dipole trap combined with a weak magnetic quadrupole field as used for magneto-optical trapping to enhance the confinement in axial direction. Efficient forced evaporative cooling to the phase transition is achieved in this weak hybrid trap via reduction of the laser intensity of the optical dipole trap at constant magnetic field gradient.

  3. Controlled generation of nonlinear resonances through sinusoidal lattice modes in Bose-Einstein condensate

    NASA Astrophysics Data System (ADS)

    Das, Priyam; Panigrahi, Prasanta K.

    2015-12-01

    We study Bose-Einstein condensate in the combined presence of time modulated optical lattice and harmonic trap in the mean-field approach. Through the self-similar method, we show the existence of sinusoidal lattice modes in this inhomogeneous system, commensurate with the lattice potential. A significant advantage of this system is wide tunability of the parameters through chirp management. The combined effect of the interaction, harmonic trap and lattice potential leads to the generation of nonlinear resonances, exactly where the matter wave changes its direction. When the harmonic trap is switched off, the BEC undergoes a nonlinear compression for the static optical lattice potential. For better understanding of chirp management and the nature of the sinusoidal excitation, we investigate the energy spectrum of the condensate, which clearly reveals the generation of nonlinear resonances in the appropriate regime. We have also identified a classical dynamical phase transition occurring in the system, where loss of superfluidity takes the superfluid phase to an insulating state.

  4. Steam side droplet erosion in titanium tubed condensers -- Experiences and remedies

    SciTech Connect

    Tavast, J.O.

    1996-12-31

    In general, the experience of titanium tubed turbine condensers is more than satisfactory. Steam side droplet erosion attack is however a concern in for example many of the Swedish and Finnish nuclear power plants. In this paper, the author`s experiences of droplet erosion as well as of remedies against droplet erosion are discussed. Possible remedies include plugging and installation of protective shields. The currently most favored remedy is partial retubing with more resistant materials. A number of accelerated tests have been performed in order to qualify potential tube materials regarding resistance towards droplet erosion. Highly alloyed stainless steels seem to have the best resistance. Some hard titanium alloys as well as nitriding of conventional titanium also seem promising. In severe cases a combination of several remedies may be necessary, e.g., partial retubing in combination with installation of a local moisture separator. For a new condenser the risk for droplet erosion can be reduced in the design stage.

  5. Alcohol LOX Steam Generator Test Experience

    NASA Astrophysics Data System (ADS)

    Schaefer, K.; Dommers, M.

    2004-10-01

    At the DLR test centre in Lampoldshausen there is a long experience in the development of rocket steam generators as a main subsystem for the altitude simulation. The rocket steam generators make it possible to supply the required quantities of steam at short notice with reduced investment and operating costs. The rocket steam generators are based on the combustion of liquid oxygen (LOX) and ethyl alcohol (ALC). The paper deals with the experience of the development of the steam generators and the operation at the altitude simulation P1.0 for satellite propulsion and P4.2 for altitude simulation of AESTUS upper stage engine.

  6. A new experiment for investigating evaporation and condensation of cryogenic propellants

    NASA Astrophysics Data System (ADS)

    Bellur, K.; Médici, E. F.; Kulshreshtha, M.; Konduru, V.; Tyrewala, D.; Tamilarasan, A.; McQuillen, J.; Leão, J. B.; Hussey, D. S.; Jacobson, D. L.; Scherschligt, J.; Hermanson, J. C.; Choi, C. K.; Allen, J. S.

    2016-03-01

    Passive and active technologies have been used to control propellant boil-off, but the current state of understanding of cryogenic evaporation and condensation in microgravity is insufficient for designing large cryogenic depots critical to the long-term space exploration missions. One of the key factors limiting the ability to design such systems is the uncertainty in the accommodation coefficients (evaporation and condensation), which are inputs for kinetic modeling of phase change. A novel, combined experimental and computational approach is being used to determine the accommodation coefficients for liquid hydrogen and liquid methane. The experimental effort utilizes the Neutron Imaging Facility located at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland to image evaporation and condensation of hydrogenated propellants inside of metallic containers. The computational effort includes numerical solution of a model for phase change in the contact line and thin film regions as well as an CFD effort for determining the appropriate thermal boundary conditions for the numerical solution of the evaporating and condensing liquid. Using all three methods, there is the possibility of extracting the accommodation coefficients from the experimental observations. The experiments are the first known observation of a liquid hydrogen menisci condensing and evaporating inside aluminum and stainless steel cylinders. The experimental technique, complimentary computational thermal model and meniscus shape determination are reported. The computational thermal model has been shown to accurately track the transient thermal response of the test cells. The meniscus shape determination suggests the presence of a finite contact angle, albeit very small, between liquid hydrogen and aluminum oxide.

  7. Observations of condensation nuclei in the 1987 airborne Antarctic ozone experiment

    NASA Technical Reports Server (NTRS)

    Wilson, J. C.; Smith, S. D.; Ferry, G. V.; Loewenstein, M.

    1988-01-01

    The condensation nucleus counter (CNC) flown of the NASA ER-2 in the Airborne Antarctic Ozone Experiment provides a measurement of the number mixing ratio of particles which can be grown by exposure to supersaturated n-butyl alcohol vapor to diameters of a few microns. Such particles are referred to as condensation nuclei (CN). The ER-2 CNC was calibrated with aerosols of known size and concentration and was found to provide an accurate measure of the number concentration of particles larger than about 0.02 micron. Since the number distribution of stratospheric aerosols is usually dominated by particles less than a few tenths of micron in diameter, the upper cutoff of the ER-2 CNC has not been determined experimentally. However, theory suggests that the sampling and counting efficiency should remain near one for particles as large as 1 micron in diameter. Thus, the CN mixing ratio is usually a good measure of the mixing ratio of submicron particles.

  8. Quark masses and mixings in the RS1 model with a condensing 4th generation

    NASA Astrophysics Data System (ADS)

    Hernández, A. E. Cárcamo; Dib, Claudio O.; Neill, Nicolás A.; Zerwekh, Alfonso R.

    2012-02-01

    We study the hierarchy of quark masses and mixings in a model based on a 5-dimensional spacetime with constant curvature of Randall-Sundrum type with two branes, where the Electroweak Symmetry Breaking is caused dynamically by the condensation of a 4th generation of quarks, due to underlying physics from the 5D bulk and the first KK gluons. We first study the hierarchy of quark masses and mixings that can be obtained from purely adjusting the profile localizations, finding that realistic masses are not reproduced unless non trivial hierarchies of underlying 4-fermion interactions from the bulk are included. Then we study global U(1) symmetries that can be imposed in order to obtain non-symmetric modified Fritzsch-like textures in the mass matrices that reproduce reasonably well quark masses and CKM mixings.

  9. Generativity: Lived Experience as Curricular Content.

    ERIC Educational Resources Information Center

    Wallin, Jason; Graham, Tanya

    2002-01-01

    Modern educational practice, inspired by the scientific rationalism of the 17th and 18th centuries, focuses on control, certainty, and order, thus rendering students' experiences superficial. Generativity "finds" the curriculum in students' life experiences, giving them relevance and the opportunity to be explored. Where life is not the source of…

  10. Direct-contact condensers for open-cycle OTEC applications: Model validation with fresh water experiments for structured packings

    SciTech Connect

    Bharathan, D.; Parsons, B.K.; Althof, J.A.

    1988-10-01

    The objective of the reported work was to develop analytical methods for evaluating the design and performance of advanced high-performance heat exchangers for use in open-cycle thermal energy conversion (OC-OTEC) systems. This report describes the progress made on validating a one-dimensional, steady-state analytical computer of fresh water experiments. The condenser model represents the state of the art in direct-contact heat exchange for condensation for OC-OTEC applications. This is expected to provide a basis for optimizing OC-OTEC plant configurations. Using the model, we examined two condenser geometries, a cocurrent and a countercurrent configuration. This report provides detailed validation results for important condenser parameters for cocurrent and countercurrent flows. Based on the comparisons and uncertainty overlap between the experimental data and predictions, the model is shown to predict critical condenser performance parameters with an uncertainty acceptable for general engineering design and performance evaluations. 33 refs., 69 figs., 38 tabs.

  11. Direct-contact condensers for open-cycle OTEC applications: Model validation with fresh water experiments for structured packings

    NASA Astrophysics Data System (ADS)

    Bharathan, D.; Parsons, B. K.; Althof, J. A.

    1988-10-01

    The objective of the reported work was to develop analytical methods for evaluating the design and performance of advanced high-performance heat exchangers for use in open-cycle thermal energy conversion (OC-OTEC) systems. This report describes the progress made on validating a one-dimensional, steady-state analytical computer of fresh water experiments. The condenser model represents the state of the art in direct-contact heat exchange for condensation for OC-OTEC applications. This is expected to provide a basis for optimizing OC-OTEC plant configurations. Using the model, we examined two condenser geometries, a cocurrent and a countercurrent configuration. This report provides detailed validation results for important condenser parameters for cocurrent and countercurrent flows. Based on the comparisons and uncertainty overlap between the experimental data and predictions, the model is shown to predict critical condenser performance parameters with an uncertainty acceptable for general engineering design and performance evaluations.

  12. Demonstration of beneficial uses of warm water from condensers of electric-generating plants

    SciTech Connect

    Boyd, L.L.; Ashley, G.C.; Hietala, J.S.; Stansfield, R.V.; Tonkinson, T.R.C.

    1980-05-01

    The report gives results of a project to demonstrate that warmed cooling water from condensers of electric generating plants can effectively and economically heat greenhouses. The 0.2-hectare demonstration greenhouse, at Northern States Power Co.'s Sherburne County (Sherco) Generating Plant, used 29.4 C water to heat both air and soil: finned-tube commercial heat exchangers were used to heat the air; and buried plastic pipes, the soil. Warm water from the Sherco 1 cooling tower was piped over 0.8 km to the greenhouse where it was cooled from 2.7 to 5.6 C before returning to the cooling tower basin. Roses and tomatoes were the principal crops in the 3-year test, although other flowers and vegetables, and conifer seedlings were also grown. The warm water heating system supplied all the greenhouse heating requirements, even at ambient temperatures as low as -40 C. Roses, snapdragons, geraniums, tomatoes, lettuce, and evergreen seedlings were grown successfully. The demonstration proved the concept to be both technically and economically feasible at Sherco, with an apparent saving of $4500/hectare in 1978 dollars over fuel oil heating, plus an annual oil savings of about 500 cu m/hectare. Privately financed commercial greenhouses heated with warm water were built at Sherco in 1977. The commercial greenhouses will expand from 0.48 to almost 1 hectare by late 1980.

  13. Steam condensation and liquid hold-up in steam generator U-tubes during oscillatory natural circulation

    SciTech Connect

    De Santi, G.F.; Mayinger, F.

    1990-01-01

    In many accident scenarios, natural circulation is an important heat transport mechanism for long-term cooling of light water reactors. In the event of a small pipe break, with subsequent loss of primary cooling fluid loss-of-coolant accident (LOCA), or under abnormal operating conditions, early tripping of the main coolant pumps can be actuated. Primary fluid flow will then progress from forced to natural convection. Understanding of the flow regimes and heat-removal mechanisms in the steam generators during the entire transient is of primary importance to safety analysis. Flow oscillations during two-phase natural circulation experiments for pressurized water reactors (PWRs) with inverted U-tube steam generators occur at high pressure and at a primary inventory range between two-phase circulation and reflex heat removal. This paper deals with the oscillatory flow behavior that was observed in the LOBI-MOD2 facility during the transition period between two-phase natural circulation and reflex condensation.

  14. Condensates and quasiparticles in inflationary cosmology: Mass generation and decay widths

    NASA Astrophysics Data System (ADS)

    Boyanovsky, Daniel

    2012-06-01

    During de Sitter inflation massless particles of minimally coupled scalar fields acquire a mass and a decay width thereby becoming quasiparticles. For bare massless particles nonperturbative infrared radiative corrections lead to a self-consistent generation of mass, for a quartic self-interaction M∝λ1/4H, and for a cubic self-interaction the mass is induced by the formation of a nonperturbative condensate leading to M∝λ1/3H2/3. These radiatively generated masses restore de Sitter invariance and result in anomalous scaling dimensions of superhorizon fluctuations. We introduce a generalization of the nonperturbative Wigner-Weisskopf method to obtain the time evolution of quantum states that include the self-consistent generation of mass and regulate the infrared behavior. The infrared divergences are manifest as poles in Δ=M2/3H2 in the single particle self-energies, leading to a rearrangement of the perturbative series nonanalytic in the couplings. A set of simple rules that yield the leading order infrared contributions to the decay width are obtained and implemented. The lack of kinematic thresholds entail that all particle states acquire a decay width, dominated by the emission and absorption of superhorizon quanta ∝(λ/H)4/3[H/kph(η)]6; λ[H/kph(η)]6 for cubic and quartic couplings respectively to leading order in M/H. The decay of single particle quantum states hastens as their wave vectors cross the Hubble radius and their width is related to the highly squeezed limit of the bi- or trispectrum of scalar fluctuations respectively.

  15. Pinch Experiments in a Table Top Generator

    SciTech Connect

    Pavez, Cristian; Moreno, Jose; Soto, Leopoldo; Tarifeno, Ariel

    2009-01-21

    The design and construction of a table top multipurpose capacitor bank of hundred of Joules and hundred of kiloAmperes conceived to be used in small scale Z-pinch experiments is reported. A recent result on a Z-pinch gas embedded discharge using hollow conical electrodes done in a similar table top generator is also presented.

  16. Bose-Einstein Condensation in a Dilute Gas; the First 70 Years and Some Recent Experiments

    NASA Astrophysics Data System (ADS)

    Cornell, E. A.; Wieman, C. E.

    Bose-Einstein condensation, or BEC, has a long and rich history dating from the early 1920s. In this article we will trace briefly over this history and some of the developments in physics that made possible our successful pursuit of BEC in a gas. We will then discuss what was involved in this quest. In this discussion we will go beyond the usual technical description to try and address certain questions that we now hear frequently, but are not covered in our past research papers. These are questions along the lines of ``How did you get the idea and decide to pursue it? Did you know it was going to work? How long did it take you and why?'' We will review some of our favorites from among the experiments we have carried out with BEC. There will then be a brief encore on why we are optimistic that BEC can be created with nearly any species of magnetically trappable atom. Throughout this article we will try to explain what makes BEC in a dilute gas so interesting, unique, and experimentally challenging. This article is our ``Nobel Lecture'' and as such takes a relatively personal approach to the story of the development of experimental Bose-Einstein condensation. For a somewhat more scholarly treatment of the history, the interested reader is referred to E. A. Cornell, J. R. Ensher and C. E. Wieman, ``Experiments in dilute atomic Bose-Einstein condensation in Bose-Einstein Condensation in Atomic Gases, Proceedings of the International School of Physics ``Enrico Fermi'' Course CXL'' (M. Inguscio, S. Stringari and C. E. Wieman, Eds., Italian Physical Society, 1999), pp. 15-66, which is also available as cond-mat/9903109. For a reasonably complete technical review of the three years of explosive progress that immediately followed the first observation of BEC, we recommend reading the above article in combination with the corresponding review from Ketterle, cond-mat/9904034.

  17. Reduced gravity boiling and condensing experiments simulated with the COBRA/TRAC computer code

    NASA Technical Reports Server (NTRS)

    Cuta, Judith M.; Krotiuk, William

    1988-01-01

    A series of reduced-gravity two-phase flow experiments has been conducted with a boiler/condenser apparatus in the NASA KC-135 aircraft in order to obtain basic thermal-hydraulic data applicable to analytical design tools. Several test points from the KC-135 tests were selected for simulation by means of the COBRA/TRAC two-fluid, three-field thermal-hydraulic computer code; the points were chosen for a 25-90 percent void-fraction range. The possible causes for the lack of agreement noted between simulations and experiments are explored, with attention to the physical characteristics of two-phase flow in one-G and near-zero-G conditions.

  18. Interim Report: Air-Cooled Condensers for Next Generation Geothermal Power Plants Improved Binary Cycle Performance

    SciTech Connect

    Daniel S. Wendt; Greg L. Mines

    2010-09-01

    As geothermal resources that are more expensive to develop are utilized for power generation, there will be increased incentive to use more efficient power plants. This is expected to be the case with Enhanced Geothermal System (EGS) resources. These resources will likely require wells drilled to depths greater than encountered with hydrothermal resources, and will have the added costs for stimulation to create the subsurface reservoir. It is postulated that plants generating power from these resources will likely utilize the binary cycle technology where heat is rejected sensibly to the ambient. The consumptive use of a portion of the produced geothermal fluid for evaporative heat rejection in the conventional flash-steam conversion cycle is likely to preclude its use with EGS resources. This will be especially true in those areas where there is a high demand for finite supplies of water. Though they have no consumptive use of water, using air-cooling systems for heat rejection has disadvantages. These systems have higher capital costs, reduced power output (heat is rejected at the higher dry-bulb temperature), increased parasitics (fan power), and greater variability in power generation on both a diurnal and annual basis (larger variation in the dry-bulb temperature). This is an interim report for the task ‘Air-Cooled Condensers in Next- Generation Conversion Systems’. The work performed was specifically aimed at a plant that uses commercially available binary cycle technologies with an EGS resource. Concepts were evaluated that have the potential to increase performance, lower cost, or mitigate the adverse effects of off-design operation. The impact on both cost and performance were determined for the concepts considered, and the scenarios identified where a particular concept is best suited. Most, but not all, of the concepts evaluated are associated with the rejection of heat. This report specifically addresses three of the concepts evaluated: the use of

  19. Operational experiences of a downhole steam generator

    NASA Astrophysics Data System (ADS)

    Marshall, B. W.

    The US Department of Energy supported the development of downhole steam generators for enhanced oil recovery as a part of Project DEEP STEAM. A final step in the development program was to deploy a downhole steam generator in the field to demonstrate its reliable operation and to evaluate the effect of the combined steam/exhaust products effluent on the reservoir. Sandia National Laboratories entered into an agreement with the City of Long Beach to place two direct contact, high pressure combustors in the Wilmington Field in Long Beach, California. These units one downhole and the other on the surface, have now been operated for a few months and gas communication with the production wells measured. The operational experience of this field experiment are discussed.

  20. Operational experiences of a downhole steam generator

    SciTech Connect

    Marshall, B.W.

    1982-01-01

    The US Department of Energy has supported the development of downhole steam generators for enhanced oil recovery as a part of Project DEEP STEAM. A final step in the development program was to deploy a downhole steam generator (DHSG) in the field to demonstrate its reliable operation and to evaluate the effect of the combined steam/exhaust products effluent on the reservoir. Sandia National Laboratories entered into an agreement with the City of Long Beach to place two direct contact, high pressure combustors in the Wilmington Field in Long Beach, California. These units one downhole and the other on the surface, have now been operated for a few months and gas communication with the production wells measured. The operational experience of this field experiment are discussed.

  1. Yang-Baxter integrable models in experiments: from condensed matter to ultracold atoms

    NASA Astrophysics Data System (ADS)

    Batchelor, Murray T.; Foerster, Angela

    2016-04-01

    The Yang-Baxter equation has long been recognised as the masterkey to integrability, providing the basis for exactly solved models which capture the fundamental physics of a number of realistic classical and quantum systems. In this article we provide an introductory survey of the impact of Yang-Baxter integrable models on experiments in condensed matter physics and ultracold atoms. A number of prominent examples are covered, including the hard-hexagon model, the Heisenberg spin chain, the transverse quantum Ising chain, a spin ladder model, the Lieb-Liniger Bose gas, the Gaudin-Yang Fermi gas and the two-site Bose-Hubbard model. The review concludes by pointing to some other recent developments with promise for further progress.

  2. Investigation and mitigation of condensation induced water hammer by stratified flow experiments

    NASA Astrophysics Data System (ADS)

    Kadakia, Hiral J.

    This research primarily focuses on the possibility of using stratified flow in preventing an occurrence of condensation induced water hammer (CIWH) in horizontal pipe involving steam and subcooled water. A two-phase flow loop simulating the passive safety systems of an advanced light water reactor was constructed and a series of stratified flow experiments were carried out involving a system of subcooled water, saturated water, and steam. Special instruments were designed to measure steam flow rate and subcooled liquid velocity. These experiments showed that when flow field conditions meet certain criteria CIWH does occur. Flow conditions used in experiments were typically observed in passive safety systems of an advanced light water cooled reactor. This research summarizes a) literature research and other experimental data that signify an occurrence of CIWH, b) experiments in an effort to show an occurrence of CIWH and the ability to prevent CIWH, c) qualitative and quantitative results to underline the mechanism of CIWH, d) experiments that show CIWH can be prevented under certain conditions, and e) guidelines for the safe operating conditions. Based on initial experiment results it was observed that Bernoulli's effect can play an important role in wave formation and instability. A separate effect table top experiment was constructed with plexi-glass. A series of entrance effect tests and stratified experiments were carried out with different fluids to study wave formation and wave bridging. Special test series experiments were carried out to investigate the presence of a saturated layer. The effect of subcooled water and steam flow on wedge length and depth were recorded. These experiments helped create a model which calculates wedge and depth of wedge for a given condition of steam and subcooled water. A very good comparison between the experiment results and the model was obtained. These experiments also showed that the presence of saturated layer can mitigate

  3. Interstellar silicate analogs for grain-surface reaction experiments: Gas-phase condensation and characterization of the silicate dust grains

    SciTech Connect

    Sabri, T.; Jäger, C.; Gavilan, L.; Lemaire, J. L.; Vidali, G.; Henning, T.

    2014-01-10

    Amorphous, astrophysically relevant silicates were prepared by laser ablation of siliceous targets and subsequent quenching of the evaporated atoms and clusters in a helium/oxygen gas atmosphere. The described gas-phase condensation method can be used to synthesize homogeneous and astrophysically relevant silicates with different compositions ranging from nonstoichiometric magnesium iron silicates to pyroxene- and olivine-type stoichiometry. Analytical tools have been used to characterize the morphology, composition, and spectral properties of the condensates. The nanometer-sized silicate condensates represent a new family of cosmic dust analogs that can generally be used for laboratory studies of cosmic processes related to condensation, processing, and destruction of cosmic dust in different astrophysical environments. The well-characterized silicates comprising amorphous Mg{sub 2}SiO{sub 4} and Fe{sub 2}SiO{sub 4}, as well as the corresponding crystalline silicates forsterite and fayalite, produced by thermal annealing of the amorphous condensates, have been used as real grain surfaces for H{sub 2} formation experiments. A specifically developed ultra-high vacuum apparatus has been used for the investigation of molecule formation experiments. The results of these molecular formation experiments on differently structured Mg{sub 2}SiO{sub 4} and Fe{sub 2}SiO{sub 4} described in this paper will be the topic of the next paper of this series.

  4. Advances in modelling of condensation phenomena

    SciTech Connect

    Liu, W.S.; Zaltsgendler, E.; Hanna, B.

    1997-07-01

    The physical parameters in the modelling of condensation phenomena in the CANDU reactor system codes are discussed. The experimental programs used for thermal-hydraulic code validation in the Canadian nuclear industry are briefly described. The modelling of vapour generation and in particular condensation plays a key role in modelling of postulated reactor transients. The condensation models adopted in the current state-of-the-art two-fluid CANDU reactor thermal-hydraulic system codes (CATHENA and TUF) are described. As examples of the modelling challenges faced, the simulation of a cold water injection experiment by CATHENA and the simulation of a condensation induced water hammer experiment by TUF are described.

  5. Laboratory Experiments of Rip Current Generation

    NASA Astrophysics Data System (ADS)

    Garnier, R.; Coco, G.; Lomonaco, P.; Dalrymple, R. A.; Alvarez, A.; Gonzalez, M.; Medina, R.

    2014-12-01

    The hypothesis of rip current generation from purely hydrodynamic processes is here investigated through laboratory experiments. The experiments have been performed at the Cantabria Coastal and Ocean Basin (CCOB) with a segmented wavemaker consisting of 64 waveboards. The basin measures 25m in the cross-shore and 32m in the alongshore direction and the water depth at the wavemaker is 1m. A concrete plane sloping (1:5) beach has been built in the opposite side of the wave machine, its toe is 15m from the waveboards. Reflective lateral walls covered the full length of the basin. The set of instruments consists of 33 wave gauges deployed along two longshore and two cross-shore transects, 7 acoustic Doppler velocimeters and 15 run-up wires. Furthermore a set of two cameras has been synchronized with the data acquisition system. Two types of experiments have been performed to specifically study the generation of rip currents under wave group forcing. First, similarly to the experiments of Fowler and Dalrymple (Proc. 22nd Int. Conf. Coast. Eng.,1990), two intersecting wave trains with opposite directions have been imposed. They give rise to the formation of a non-migrating rip current system with a wavelength that depends on wave frequency and direction. Second, single wave trains with alongshore periodic amplitude attenuation have been imposed. Although the attenuation has been set such that the incident wave field has the same envelope as in the first type of experiments, the rip current system differs due to diffraction and interference processes. The results for different wave conditions (maximum incident wave height from 0.2m to 0.4m, wave period from 1.4s to 2s) will be presented and the intensity of the rip currents will be compared to the alongshore variation in wave set-up. This research is part of the ANIMO project funded by the Spanish Government under contract BIA2012-36822.

  6. Apollo experience report: Power generation system

    NASA Technical Reports Server (NTRS)

    Bell, D., III; Plauche, F. M.

    1973-01-01

    A comprehensive review of the design philosophy and experience of the Apollo electrical power generation system is presented. The review of the system covers a period of 8 years, from conception through the Apollo 12 lunar-landing mission. The program progressed from the definition phase to hardware design, system development and qualification, and, ultimately, to the flight phase. Several problems were encountered; however, a technology evolved that enabled resolution of the problems and resulted in a fully manrated power generation system. These problems are defined and examined, and the corrective action taken is discussed. Several recommendations are made to preclude similar occurrences and to provide a more reliable fuel-cell power system.

  7. Development of Flow Boiling and Condensation Experiment on the International Space Station- Normal and Low Gravity Flow Boiling Experiment Development and Test Results

    NASA Technical Reports Server (NTRS)

    Nahra, Henry K.; Hall, Nancy R.; Hasan, Mohammad M.; Wagner, James D.; May, Rochelle L.; Mackey, Jeffrey R.; Kolacz, John S.; Butcher, Robert L.; Frankenfield, Bruce J.; Mudawar, Issam; Konichi, Chris; Hyounsoon, Lee

    2013-01-01

    Flow boiling and condensation have been identified as two key mechanisms for heat transport that are vital for achieving weight and volume reduction as well as performance enhancement in future space systems. Since inertia driven flows are demanding on power usage, lower flows are desirable. However, in microgravity, lower flows are dominated by forces other than inertia (like the capillary force). It is of paramount interest to investigate limits of low flows beyond which the flow is inertial enough to be gravity independent. One of the objectives of the Flow Boiling and Condensation Flight Experiment sets to investigate these limits for flow boiling and condensation. A two-phase flow loop consisting of a Flow Boiling Module and two Condensation Modules has been developed to experimentally study flow boiling condensation heat transfer in the reduced gravity environment provided by the reduced gravity platform. This effort supports the development of a flow boiling and condensation facility for the International Space Station (ISS). The closed loop test facility is designed to deliver the test fluid, FC-72 to the inlet of any one of the test modules at specified thermodynamic and flow conditions. The zero-g-aircraft tests will provide subcooled and saturated flow boiling critical heat flux and flow condensation heat transfer data over wide range of flow velocities. Additionally, these tests will verify the performance of all gravity sensitive components, such as evaporator, condenser and accumulator associated with the two-phase flow loop. We will present in this paper the breadboard development and testing results which consist of detailed performance evaluation of the heater and condenser combination in reduced and normal gravity. We will also present the design of the reduced gravity aircraft rack and the results of the ground flow boiling heat transfer testing performed with the Flow Boiling Module that is designed to investigate flow boiling heat transfer and

  8. Key points of condenser refurbishment illustrated by our experience on Russian technology nuclear power stations

    SciTech Connect

    Somville, C.

    1998-07-01

    In 1990, the refurbishment of the condensers of the VVER 440 MW LOVIISA 2 Finnish power station was the first reference of GEC ALSTHOM Delas on a Russian type nuclear power station, covering the optimization studies, technical and-economical choices, manufacture and site operations. The current contract for the condenser renovation of the 4 units of the VVER 440 MW PAKS Hungarian power station goes even further through an investment of this company in a local manufacturing installation and a significant participation of the local industry. Their expertise has helped reducing site operation times from 28 days for one condenser of one Loviisa unit, to 26 days for two condensers of one Paks unit. This paper describes the various aspects and the improvements brought for both operations and highlights the technical and economical key advantages of a condenser renovation (quick return on investment, better performances, reliability and life extension of the power station).

  9. Experiences in production and corrosion monitoring for a gas condensate field containing CO{sub 2}

    SciTech Connect

    Oberndorfer, M.; Dornstauder, K.; Brunner, W.

    1998-12-31

    The field Hoflein is located 10 km NW of Vienna. Gas condensate is produced out of 9 wells at the dew point of 28.1 MPa and 78 C. The reservoir fluid is lean but contains more than 16% CO{sub 2}. Lab test preceded the selection of the inhibitor for the carbon steel. Critical parts of the installations had 13%Cr steel. This paper describes the inhibitor testing procedures and the monitoring of the corrosion process by OMV Austria. The produced reservoir fluids and the critical components in the water (Cl, Fe, pH, inhibitor concentration) have been recorded over the years in various locations. Fluid analysis, corrosion coupon data visual inspection and caliper measurements of field installation document a high degree of protection. Recently the reservoir underwent a reevaluation in which the reserves could be doubled. This gave the incentive to produce at higher rates (from 8 to probably 16 m/s). Inhibitors of the 3rd generation that work even under high velocities were applied. For this case a test loop in the laboratory is described which allows for emulating the high velocity flow conditions that are planned in the field and where the inhibitors can be tested and selected.

  10. Role of minerals in the thermal alteration of organic matter. I - Generation of gases and condensates under dry condition

    NASA Technical Reports Server (NTRS)

    Tannenbaum, E.; Kaplan, I. R.

    1985-01-01

    Pyrolysis experiments conducted at 200 and 300 C on kerogen and bitumen from the Monterey formation and on the Green River Formation kerogen with montmorillonite, illite, and calcite added are described. The pyrolysis products are identified and gas and condensate analyses are performed. A catalytic effect is detected in the pyrolysis of kerogen with montmorillonite; however, illite and calcite display no catalytic activity. The increased production of C1-C6 hydrocarbons and the dominance of branched hydrocarbons in the C4-C6 range reveals a catalytic influence. It is observed that the catalysis of montmorillonite is greater during bitumen pyrolysis than for kerogen, and catalysis with minerals affects the production of CO2. It is concluded that a mineral matrix is important in determining the type and amount of gases and condensates forming from organic matter under thermal stress.

  11. Formation of Polycyclic Aromatic Hydrocarbons and Carbonaceous Solids in Gas-Phase Condensation Experiments

    NASA Astrophysics Data System (ADS)

    Jäger, C.; Huisken, F.; Mutschke, H.; Jansa, I. Llamas; Henning, Th.

    2009-05-01

    Carbonaceous grains represent a major component of cosmic dust. In order to understand their formation pathways, they have been prepared in the laboratory by gas-phase condensation reactions such as laser pyrolysis and laser ablation. Our studies demonstrate that the temperature in the condensation zone determines the formation pathway of carbonaceous particles. At temperatures lower than 1700 K, the condensation by-products are mainly polycyclic aromatic hydrocarbons (PAHs) that are also the precursors or building blocks for the condensing soot grains. The low-temperature condensates contain PAH mixtures that are mainly composed of volatile three to five ring systems. At condensation temperatures higher than 3500 K, fullerene-like carbon grains and fullerene compounds are formed. Fullerene fragments or complete fullerenes equip the nucleating particles. Fullerenes can be identified as soluble components. Consequently, condensation products in cool and hot astrophysical environments such as cool and hot asymptotic giant branch stars or Wolf-Rayet stars should be different and should have distinct spectral properties.

  12. DETERMINATION OF TRACE AMOUNTS OF SELENIUM IN CORN, LETTUCE, POTATOES, SOYBEANS, AND WHEAT BY HYDRIDE GENERATION/CONDENSATION AND FLAME ATOMIC ABSORPTION SPECTROMETRY

    EPA Science Inventory

    Because of the nutritional and toxicological significance of low selenium concentrations in agricultural crops, a procedure utilizing wet digestion followed by hydride generation/condensation-flame atomic absorption was developed for the routine analysis of selenium in different ...

  13. Infrasound Generation from the Source Physics Experiments

    NASA Astrophysics Data System (ADS)

    Preston, L. A.; Schramm, K. A.; Jones, K. R.

    2015-12-01

    Understanding the acoustic and infrasound source generation mechanisms from underground explosions is of great importance for usage of this unique data type in non-proliferation activities. One of the purposes of the Source Physics Experiments (SPE), a series of underground explosive shots at the Nevada National Security Site (NNSS), is to gain an improved understanding of the generation and propagation of physical signals, such as seismic and infrasound, from the near to far field. Two of the SPE shots (SPE-1 and SPE-4') were designed to be small "Green's Function" sources with minimal spall or permanent surface deformation. We analyze infrasound data collected from these two shots at distances from ~300 m to ~1 km and frequencies up to 20 Hz. Using weather models based upon actual observations at the times of these sources, including 3-D variations in topography, temperatures, pressures, and winds, we synthesized full waveforms using Sandia's moving media acoustic propagation simulation suite. Several source mechanisms were simulated and compared and contrasted with observed waveforms using full waveform source inversion. We will discuss results of these source inversions including the relative roll of spall from these small explosions. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  14. The next-generation BLASTPol experiment

    NASA Astrophysics Data System (ADS)

    Dober, Bradley J.; Ade, Peter A. R.; Ashton, Peter; Angilè, Francesco E.; Beall, James A.; Becker, Dan; Bradford, Kristi J.; Che, George; Cho, Hsiao-Mei; Devlin, Mark J.; Fissel, Laura M.; Fukui, Yasuo; Galitzki, Nicholas; Gao, Jiansong; Groppi, Christopher E.; Hillbrand, Seth; Hilton, Gene C.; Hubmayr, Johannes; Irwin, Kent D.; Klein, Jeffrey; Van Lanen, Jeff; Li, Dale; Li, Zhi-Yun; Lourie, Nathan P.; Mani, Hamdi; Martin, Peter G.; Mauskopf, Philip; Nakamura, Fumitaka; Novak, Giles; Pappas, David P.; Pascale, Enzo; Santos, Fabio P.; Savini, Giorgio; Scott, Douglas; Stanchfield, Sara; Ullom, Joel N.; Underhill, Matthew; Vissers, Michael R.; Ward-Thompson, Derek

    2014-07-01

    The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) is a suborbital mapping experiment designed to study the role magnetic fields play in star formation. BLASTPol has had two science flights from McMurdo Station, Antarctica in 2010 and 2012. These flights have produced thousands of polarization vectors at 250, 350 and 500 microns in several molecular cloud targets. We present the design, specifications, and progress towards the next-generation BLASTPol experiment (BLAST-TNG). BLAST-TNG will fly a 40% larger diameter primary mirror, with almost 8 times the number of polarization-sensitive detectors resulting in a factor of 16 increase in mapping speed. With a spatial resolution of 2200 and four times the field of view (340 arcmin2) of BLASTPol, BLAST-TNG will bridge the angular scales between Planck's all-sky maps with 50 resolution and ALMA's ultra-high resolution narrow (~ 2000) fields. The new receiver has a larger cryogenics volume, allowing for a 28 day hold time. BLAST-TNG employs three arrays of Microwave Kinetic Inductance Detectors (MKIDs) with 30% fractional bandwidth at 250, 350 and 500 microns. In this paper, we will present the new BLAST-TNG instrument and science objectives.

  15. Calibration of an explosives vapor generator based on vapor diffusion from a condensed phase

    SciTech Connect

    Parmeter, J.E.; Rhykerd, L. Jr.; Conrad, F.J.; Tiano, G.S.; Preston, D.; Eiceman, G.A.; Arnold, J.T.

    1995-12-31

    Development of a vapor generator for consistently producing accurate amounts of vapor from low vapor pressure explosive materials is a pressing need within the explosives detection community. Of particular importance for reproducibility and widespread acceptance of results is the correlation of such a vapor generator to a National Institute of Standards and Technology (NIST) mass standard. This paper describes an explosives vapor generator recently developed at Varian in which a solid explosive sample in a precision bore glass tube is put in an oven at constant temperature, and vapor diff-using from the top of the tube is entrained in a carrier gas flow. The rate of vapor output is thus dependent on both the equilibrium vapor pressure of the solid at oven temperature and the rate of diffusion up the length of the tube. Correlation to a NIST mass standard is achieved by periodic weighing of the sample tube on a microbalance. We report results obtained with the explosives TNT and RDX. Results for TNT show that the mass output rate is constant over hundreds of hours of continuous use, with outputs of {approximately} 10--2000 pg/sec for oven temperatures in the range of 60--120{degrees}C. Both the mass loss experiments and calibration with an ion mobility spectrometer (IMS) give a TNT mass output value of 85 pg/sec at 79{degrees}C, and this result is supported by transport theory calculations. Mass loss curves for RDX are also linear with time, and show the expected exponential increase of mass output with oven temperature.

  16. A Next-Generation Apparatus for Lithium Optical Lattice Experiments

    NASA Astrophysics Data System (ADS)

    Keshet, Aviv

    Quantum simulation is emerging as an ambitious and active subfield of atomic physics. This thesis describes progress towards the goal of simulating condensed matter systems, in particular the physics of the Fermi-Hubbard model, using ultracold Lithium atoms in an optical lattice. A major goal of the quantum simulation program is to observe phase transitions of the Hubbard model, into Neal antiferromagnetic phases and d-wave superfluid phases. Phase transitions are generally accompanied by a change in an underlying correlation in a physical system. Such correlations may be most amenable to probing by looking at fluctuations in the system. Experimental techniques for probing density and magnetization fluctuations in a variety of atomic Fermi systems are developed. The suppression of density fluctuations (or atom "shot noise") in an ideal degenerate Fermi gas is observed by absorption imaging of time-of-flight expanded clouds. In-trap measurements of density and magnetization fluctuations are not easy to probe with absorption imaging, due to their extremely high attenuation. A method to probe these fluctuations based on speckle patterns, caused by fluctuations in the index of refraction for a detuned illumination beam, is developed and applied first to weakly interacting and then to strongly interacting in-trap gases. Fluctuation probes such as these will be a crucial tool in future quantum simulation of condensed matter systems. The quantum simulation experiments that we want to perform require a complex sequence of precisely timed computer controlled events. A distributed GUI-based control system designed with such experiments in mind, The Cicero Word Generator, is described. The system makes use of a client-server separation between a user interface for sequence design and a set of output hardware servers. Output hardware servers are designed to use standard National Instruments output cards, but the client-server nature allows this to be extended to other output

  17. Flow Boiling and Condensation Experiment (FBCE) for the International Space Station

    NASA Technical Reports Server (NTRS)

    Mudawar, Issam; Hasan, Mohammad M.; Kharangate, Chirag; O'Neill, Lucas; Konishi, Chris; Nahra, Henry; Hall, Nancy; Balasubramaniam, R.; Mackey, Jeffrey

    2015-01-01

    The proposed research aims to develop an integrated two-phase flow boiling/condensation facility for the International Space Station (ISS) to serve as primary platform for obtaining two-phase flow and heat transfer data in microgravity.

  18. Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol: the significance of soluble material

    NASA Astrophysics Data System (ADS)

    Garimella, S.; Huang, Y.-w.; Seewald, J. S.; Cziczo, D. J.

    2013-11-01

    This study examines the interaction of clay mineral particles and water vapor to determine the conditions required for cloud droplet formation. Droplet formation conditions are investigated for three clay minerals: illite, sodium-rich montmorillonite, and Arizona Test Dust. Using wet and dry particle generation coupled to a differential mobility analyzer (DMA) and cloud condensation nuclei counter, the critical activation of the clay mineral particles as cloud condensation nuclei is characterized. Electron microscopy (EM) is used to determine non-sphericity in particle shape. EM is also used to determine particle surface area and account for transmission of multiply charged particles by the DMA. Single particle mass spectrometry and ion chromatography are used to investigate soluble material in wet-generated samples and demonstrate that wet and dry generation yield compositionally different particles. Activation results are analyzed in the context of both κ-Köhler theory and Frenkel, Halsey, and Hill (FHH) adsorption activation theory. This study has two main results: (1) κ-Köhler is a suitable framework, less complex than FHH theory, to describe clay mineral nucleation activity despite apparent differences in κ with respect to size. For dry-generated particles the size dependence is likely an artifact of the shape of the size distribution: there is a sharp drop-off in particle concentration at ~300 nm, and a large fraction of particles classified with a mobility diameter less than ~300 nm are actually multiply charged, resulting in a much lower critical supersaturation for droplet activation than expected. For wet-generated particles, deviation from κ-Köhler theory is likely a result of the dissolution and redistribution of soluble material. (2) Wet-generation is found to be unsuitable for simulating the lofting of fresh dry dust because it changes the size-dependent critical supersaturations by fractionating and re-partitioning soluble material.

  19. Spectral probing of impact-generated vapor in laboratory experiments

    NASA Astrophysics Data System (ADS)

    Schultz, Peter H.; Eberhardy, Clara A.

    2015-03-01

    High-speed spectra of hypervelocity impacts at the NASA Ames Vertical Gun Range (AVGR) captured the rapidly evolving conditions of impact-generated vapor as a function of impact angle, viewpoint, and time (within the first 50 μs). Impact speeds possible at the AVGR (<7 km/s) are insufficient to induce significant vaporization in silicates, other than the high-temperature (but low-mass) jetting component created at first contact. Consequently, this study used powdered dolomite as a proxy for surveying the evolution and distribution of chemical constituents within much longer lasting vapor. Seven separate telescopes focused on different portions of the impact vapor plume and were connected through quartz fibers to two 0.35 cm monochromaters. Quarter-space experiments reduced the thermal background and opaque phases due to condensing particles and heated projectile fragments while different exposure times isolated components passing through different the fields of view, both above and below the surface within the growing transient cavity. At early times (<5 μs), atomic emission lines dominate the spectra. At later times, molecular emission lines dominate the composition of the vapor plume along a given direction. Layered targets and target mixtures isolated the source and reveal that much of the vaporization comes from the uppermost surface. Collisions by projectile fragments downrange also make significant contributions for impacts below 60° (from the horizontal). Further, impacts into mixtures of silicates with powdered dolomite reveal that frictional heating must play a role in vapor production. Such results have implications for processes controlling vaporization on planetary surfaces including volatile release, atmospheric evolution (formation and erosion), vapor generated by the Deep Impact collision, and the possible consequences of the Chicxulub impact.

  20. Generating ring dark solitons in an evolving Bose-Einstein condensate

    SciTech Connect

    Yang Shijie; Wu Quansheng; Zhang Shengnan; Feng Shiping; Guo Wenan; Wen Yuchuan; Yu Yue

    2007-12-15

    The successive dynamical evolution of a Bose-Einstein condensate confined in a cylindrical well is numerically studied in the framework of the time-dependent Gross-Pitaevskii equation. Interference in the nonlinear matter wave leads to concentric density rings. The phase distribution exhibits a discontinuous sequence of plateaulike belts. Abrupt jumps in the phase between adjacent belts imply large radial superfluid velocity at the borderline. This, however, does not mean large particle current because the corresponding superfluid density is nearly zero. The density zeros along with the large gradient are identified as ring dark solitons, which have a brief lifetime before evolving into other soliton states.

  1. Evaluation of condensation-induced water hammer in preheat steam generators

    SciTech Connect

    Saha, P.; Ginsberg, T.; Wu, B.J.C.; Jones, O.C. Jr.

    1980-09-01

    A review of Westinghouse 1/8-scale water hammer tests and data analysis was carried out. BNL has concluded that water hammers occurred in the feedwater line during many of the 1/8-scale tests. These events were probably caused by steam bubble entrapment and collapse in the partially-filled feedwater line. Recorded vessel pressure pulse activity under two-phase operating conditions was rare and, in those cases where pulses were recorded, the pressure pulse amplitudes were small. Either void collapse water hammers are unlikely events under these two-phase conditions, or events that did occur were attenuated in magnitude by the two-phase medium and internal structures before the pulse reached the pressure transducer. Pressure pulse attenuation in two-phase air-water media was studied experimentally at BNL. It was found that no significant attenuation could be detected in two-phase flows over distances of approximately 1 to 2 ft. The effects of internals, however, were not considered. The Westinghouse scaling laws have also been critically reviewed. An independent BNL analysis was carried out to verify the Westinghouse scaling laws. It has been found that the present state-of-the-art on the condensation heat transfer and the mechanism of vapor cavity formation precludes us from deriving any credible scaling criteria. However, it was found that under certain operating conditions the condensation-induced void collapse could be an oscillatory process. This may partially explain the apparent randomness of the water hammer phenomenon seen in most experimental studies.

  2. Elemental composition of aerosols in fourteen experiments of the Cloud Condensation Nuclei Workshop

    NASA Technical Reports Server (NTRS)

    Mach, W. H.; Hucek, R. R.

    1981-01-01

    Aeosols were collected with two Ci impactors and analyzed with proton induced X-ray emission (PIXE) for chemical composition and to detect if contamination was present. One of the impactors sampled the generated aerosols; the other impactor sampled droplets from a diffusion cloud chamber. The purpose of the experiments was to test the feasibility of a study of the transfer of chemical elements from the fine particle sizes to the coarse particle sizes, after CCN are activated and cloud droplets are formed. The data indicated that sulfur-containing aerosols did exhibit the expected transfer.

  3. Vapor Compression and Thermoelectric Heat Pump Heat Exchangers for a Condensate Distillation System: Design and Experiment

    NASA Technical Reports Server (NTRS)

    Erickson, Lisa R.; Ungar, Eugene K.

    2013-01-01

    Maximizing the reuse of wastewater while minimizing the use of consumables is critical in long duration space exploration. One of the more promising methods of reclaiming urine is the distillation/condensation process used in the cascade distillation system (CDS). This system accepts a mixture of urine and toxic stabilizing agents, heats it to vaporize the water and condenses and cools the resulting water vapor. The CDS wastewater flow requires heating and its condensate flow requires cooling. Performing the heating and cooling processes separately requires two separate units, each of which would require large amounts of electrical power. By heating the wastewater and cooling the condensate in a single heat pump unit, mass, volume, and power efficiencies can be obtained. The present work describes and compares two competing heat pump methodologies that meet the needs of the CDS: 1) a series of mini compressor vapor compression cycles and 2) a thermoelectric heat exchanger. In the paper, the system level requirements are outlined, the designs of the two heat pumps are described in detail, and the results of heat pump performance tests are provided. A summary is provided of the heat pump mass, volume and power trades and a selection recommendation is made.

  4. Chemical Composition and Cloud Condensation Nuclei Properties of Marine Aerosols during the 2005 Marine Stratus Experiment

    NASA Astrophysics Data System (ADS)

    Lee, Y.; Hudson, J.; Daum, P.; Springston, S.; Wang, J.; Senum, G.; Alexander, L.; Jayne, J.; Hubbe, J.

    2006-12-01

    Marine aerosol chemical composition and cloud condensation nuclei (CCN) spectrum were determined on board the DOE G1 aircraft during the Marine Stratus Experiment conducted over the coastal waters between Point Reyes National Seashore and Monterey Bay, California, in July 2005. Aerosol components, including sea-salt- (sodium, chloride, magnesium, methansulfonate) and terrestrial/pollution-derived (ammonium, sulfate, nitrate, organics, potassium, and calcium) were measured using the particle-into-liquid sampler-ion chromatography technique and an Aerodyne AMS at a time resolution of 4 min and 30 s, respectively, both covering the size range of ~0.08 to 1.5 micrometers. The CCN spectrum was determined at a 1-s time resolution covering a supersaturation range between 0.02% and 1%. The accumulation mode particle size- number distribution was measured using a passive cavity aerosol spectrometer probe; the cloud droplet size- number distribution was determined using a Cloud Aerosol Probe. During the campaign sulfate/organic aerosols were always present, sea-salt aerosols were observed on half of the flights, and no dust or biomass burning contribution was noted as calcium and potassium were always below their limits-of-detection. Based on CCN spectra and cloud droplet number concentrations, the typical supersaturation of the marine stratus clouds was ~0.06%, corresponding to a CCN critical diameter between 0.1 and 0.2 micrometer. This large critical diameter makes the aerosol chemical composition measured appropriate for investigating the CCN properties and marine stratus clouds. We note that while sea-salt aerosols and sulfate aerosols were most likely externally mixed, the ensemble exhibits similar CCN properties irrespective of the relative mass concentrations of these two types of aerosols, owing partly to the similar activation properties of NaCl and (NH4)2SO4 aerosols, and that sea-salt particles were larger but fewer, accounting for a small fraction of cloud

  5. Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol: the significance of soluble material

    NASA Astrophysics Data System (ADS)

    Garimella, S.; Huang, Y.-W.; Seewald, J. S.; Cziczo, D. J.

    2014-06-01

    This study examines the interaction of clay mineral particles and water vapor for determining the conditions required for cloud droplet formation. Droplet formation conditions are investigated for two common clay minerals, illite and sodium-rich montmorillonite, and an industrially derived sample, Arizona Test Dust. Using wet and dry particle generation coupled to a differential mobility analyzer (DMA) and cloud condensation nuclei counter, the critical activation of the clay mineral particles as cloud condensation nuclei is characterized. Electron microscopy (EM) is used in order to determine non-sphericity in particle shape. It is also used in order to determine particle surface area and account for transmission of multiply charged particles by the DMA. Single particle mass spectrometry and ion chromatography are used to investigate soluble material in wet-generated samples and demonstrate that wet and dry generation yield compositionally different particles. Activation results are analyzed in the context of both κ-Köhler theory (κ-KT) and Frenkel-Halsey-Hill (FHH) adsorption activation theory. This study has two main results: (1) κ-KT is the suitable framework to describe clay mineral nucleation activity. Apparent differences in κ with respect to size arise from an artifact introduced by improper size-selection methodology. For dust particles with mobility sizes larger than ~300 nm, i.e., ones that are within an atmospherically relevant size range, both κ-KT and FHH theory yield similar critical supersaturations. However, the former requires a single hygroscopicity parameter instead of the two adjustable parameters required by the latter. For dry-generated particles, the size dependence of κ is likely an artifact of the shape of the size distribution: there is a sharp drop-off in particle concentration at ~300 nm, and a large fraction of particles classified with a mobility diameter less than ~300 nm are actually multiply charged, resulting in a much

  6. Second generation experiments in fault tolerant software

    NASA Technical Reports Server (NTRS)

    Knight, J. C.

    1987-01-01

    The purpose of the Multi-Version Software (MVS) experiment is to obtain empirical measurements of the performance of multi-version systems. Twenty version of a program were prepared under reasonably realistic development conditions from the same specifications. The overall structure of the testing environment for the MVS experiment and its status are described. A preliminary version of the control system is described that was implemented for the MVS experiment to allow the experimenter to have control over the details of the testing. The results of an empirical study of error detection using self checks are also presented. The analysis of the checks revealed that there are great differences in the ability of individual programmers to design effective checks.

  7. Condensate Mixtures and Tunneling

    SciTech Connect

    Timmermans, E.

    1998-09-14

    The experimental study of condensate mixtures is a particularly exciting application of the recently developed atomic-trap Bose-Einstein condensate (BEC) technology: such multiple condensates represent the first laboratory systems of distinguishable boson superfluid mixtures. In addition, as the authors point out in this paper, the possibility of inter-condensate tunneling greatly enhances the richness of the condensate mixture physics. Not only does tunneling give rise to the oscillating particle currents between condensates of different chemical potentials, such as those studied extensively in the condensed matter Josephson junction experiments, it also affects the near-equilibrium dynamics and stability of the condensate mixtures. In particular, the stabilizing influence of tunneling with respect to spatial separation (phase separation) could be of considerable practical importance to the atomic trap systems. Furthermore, the creation of mixtures of atomic and molecular condensates could introduce a novel type of tunneling process, involving the conversion of a pair of atomic condensate bosons into a single molecular condensate boson. The static description of condensate mixtures with such type of pair tunneling suggests the possibility of observing dilute condensates with the liquid-like property of a self-determined density.

  8. Increased Availability From Improved Condenser Design

    SciTech Connect

    Harpster, Joseph W.

    2002-07-01

    Performance parameters and flow characteristics on the shell side of surface condensers are becoming better understood. Contributing to this knowledge base is the recent ability to measure the physical properties as well as the quantity of gases being removed from the condenser by air removal equipment. Reviewed here are the commonality of these data from many operating condensers obtained over the past six years and other known condenser measurements, theory and laboratory experiments. These are combined to formulate global theoretical description of condenser dynamics describing the mechanism responsible for aeration and de-aeration, excess back pressure buildup due to air ingress or generation of other noncondensable gases, and the dissolubility of corrosive gases in condensate. The theoretical description supports a dynamic model useful for deciding condenser configuration design and design improvements. Features of design found in many operating condensers that promote aeration and resulting corrosion are presented. The benefits of the model and engineering design modifications to plant life cycle management, improved condenser performance, outage reduction and reliability improvements, lost load recovery and fuel savings are discussed. (author)

  9. Circulation control lift generation experiment: Hardware development

    NASA Technical Reports Server (NTRS)

    Panontin, T. L.

    1985-01-01

    A circulation control airfoil and its accompanying hardware were developed to allow the investigation of lift generation that is independent of airfoil angle of attack and relative flow velocity. The test equipment, designed for use in a water tunnel, includes the blown airfoil, the support systems for both flow visualization and airfoil load measurement, and the fluid control system, which utilizes hydraulic technology. The primary design tasks, the selected solutions, and the unforseen problems involved in the development of these individual components of hardware are described.

  10. Plasma Motor Generator (PMG) electrodynamic tether experiment

    NASA Technical Reports Server (NTRS)

    Grossi, Mario D.

    1995-01-01

    The Plasma Motor Generator (PMG) flight of June 26, 1993 has been the most sophisticated and most successful mission that has been carried out thus far with an electrodynamic tether. Three papers from the Smithsonian Astrophysical Observatory, Washington, DC concerned with the PMG, submitted at the Fourth International Space Conference on Tethers in Space, in Washington, DC, in April 1995, are contained in this document. The three papers are (1) Electromagnetic interactions between the PMG tether and the magneto-ionic medium of the Ionosphere; (2) Tether-current-voltage characteristics, as determined by the Hollow Cathode Operation Modes; and (3) Hawaii-Hilo ground observations on the occasion for the PMG flight of June 23, 1993.

  11. Generating and manipulating quantized vortices on-demand in a Bose-Einstein condensate: A numerical study

    NASA Astrophysics Data System (ADS)

    Gertjerenken, B.; Kevrekidis, P. G.; Carretero-González, R.; Anderson, B. P.

    2016-02-01

    We numerically investigate an experimentally viable method for generating and manipulating on-demand several vortices in a highly oblate atomic Bose-Einstein condensate (BEC) in order to initialize complex vortex distributions for studies of vortex dynamics. The method utilizes moving laser beams to generate, capture, and transport vortices inside and outside the BEC. We examine in detail this methodology and show a wide parameter range of applicability for the prototypical two-vortex case, as well as case examples of producing and manipulating several vortices for which there is no net circulation, corresponding to equal numbers of positive and negative circulation vortices, and cases for which there is one net quantum of circulation. We find that the presence of dissipation can help stabilize the pinning of the vortices on their respective laser beam pinning sites. Finally, we illustrate how to utilize laser beams as repositories that hold large numbers of vortices and how to deposit individual vortices in a sequential fashion in the repositories in order to construct superfluid flows about the repository beams with several quanta of circulation.

  12. Demonstration of beneficial uses of warm water from condensers of electric generating plants. Final report, May 1975-April 1980

    SciTech Connect

    Boyd, L.L.; Ashley, G.C.; Hietala, J.S.; Stansfield, R.V.; Tonkinson, T.R.C.

    1980-05-01

    The report gives results of a project to demonstrate that warmed cooling water from condensers of electric generating plants can effectively and economically heat greenhouses. The 0.2-hectare demonstration greenhouse, at Northern States Power Co.'s Sherburne County (Sherco) Generating Plant, used 29.4 C water to heat both air and soil: finned-tube commercial heat exchangers were used to heat the air; and buried plastic pipes, the soil. Warm water from the Sherco 1 cooling tower was piped over 0.8 km to the greenhouse where it was cooled from 2.7 to 5.6 C before returning to the cooling tower basin. Roses and tomatoes were the principal crops in the 3-year test, although other flowers and vegetables, and conifer seedlings were also grown. The warm water heating system supplied all the greenhouse heating requirements, even at ambient temperatures as low as -40 C. Roses, snapdragons, geraniums, tomatoes, lettuce, and evergreen seedlings were grown successfully.

  13. Generating and manipulating quantized vortices on-demand in a Bose-Einstein condensate: A numerical study

    DOE PAGESBeta

    Gertjerenken, B.; Kevrekidis, P. G.; Carretero-González, R.; Anderson, B. P.

    2016-02-01

    Here, we numerically investigate an experimentally viable method for generating and manipulating on-demand several vortices in a highly oblate atomic Bose-Einstein condensate (BEC) in order to initialize complex vortex distributions for studies of vortex dynamics. The method utilizes moving laser beams to generate, capture, and transport vortices inside and outside the BEC. This methodology is examined in detail and shows a wide parameter range of applicability for the prototypical two-vortex case, as well as case examples of producing and manipulating several vortices for which there is no net circulation, corresponding to equal numbers of positive and negative circulation vortices, andmore » cases for which there is one net quantum of circulation. We also find that the presence of dissipation can help stabilize the pinning of the vortices on their respective laser beam pinning sites. Finally, we illustrate how to utilize laser beams as repositories that hold large numbers of vortices and how to deposit individual vortices in a sequential fashion in the repositories in order to construct superfluid flows about the repository beams with several quanta of circulation.« less

  14. Generation of atom-photon entangled states in atomic Bose-Einstein condensate via electromagnetically induced transparency

    SciTech Connect

    Kuang Leman; Zhou Lan

    2003-10-01

    In this paper, we present a method to generate continuous-variable-type entangled states between photons and atoms in atomic Bose-Einstein condensate (BEC). The proposed method involves an atomic BEC with three internal states, a weak quantized probe laser, and a strong classical coupling laser, which form a three-level {lambda}-shaped BEC system. We consider a situation where the BEC is in electromagnetically induced transparency with the coupling laser being much stronger than the probe laser. In this case, the upper and intermediate levels are unpopulated, so that their adiabatic elimination enables an effective two-mode model involving only the atomic field at the lowest internal level and the quantized probe laser field. Atom-photon quantum entanglement is created through laser-atom and interatomic interactions, and two-photon detuning. We show how to generate atom-photon entangled coherent states and entangled states between photon (atom) coherent states and atom-(photon-) macroscopic quantum superposition (MQS) states, and between photon-MQS and atom-MQS states.

  15. Vortices and turbulence in trapped atomic condensates

    PubMed Central

    White, Angela C.; Anderson, Brian P.; Bagnato, Vanderlei S.

    2014-01-01

    After more than a decade of experiments generating and studying the physics of quantized vortices in atomic gas Bose–Einstein condensates, research is beginning to focus on the roles of vortices in quantum turbulence, as well as other measures of quantum turbulence in atomic condensates. Such research directions have the potential to uncover new insights into quantum turbulence, vortices, and superfluidity and also explore the similarities and differences between quantum and classical turbulence in entirely new settings. Here we present a critical assessment of theoretical and experimental studies in this emerging field of quantum turbulence in atomic condensates. PMID:24704880

  16. Next Generation Muon g-2 Experiments

    SciTech Connect

    Hertzog, David W.

    2015-12-02

    I report on the progress of two new muon anomalous magnetic moment experiments, which are in advanced design and construction phases. The goal of Fermilab E989 is to reduce the experimental uncertainty of $a_\\mu$ from Brookhaven E821 by a factor of 4; that is, $\\delta a_\\mu \\sim 16 \\times 10^{-11}$, a relative uncertainty of 140~ppb. The method follows the same magic-momentum storage ring concept used at BNL, and pioneered previously at CERN, but muon beam preparation, storage ring internal hardware, field measuring equipment, and detector and electronics systems are all new or upgraded significantly. In contrast, J-PARC E34 will employ a novel approach based on injection of an ultra-cold, low-energy, muon beam injected into a small, but highly uniform magnet. Only a small magnetic focusing field is needed to maintain storage, which distinguishes it from CERN, BNL and Fermilab. E34 aims to roughly match the previous BNL precision in their Phase~1 installation.

  17. Next Generation Muon g - 2 Experiments

    NASA Astrophysics Data System (ADS)

    Hertzog, David W.

    2016-04-01

    I report on the progress of two new muon anomalous magnetic moment experiments, which are in advanced design and construction phases. The goal of Fermilab E989 is to reduce the experimental uncertainty of aμ from Brookhaven E821 by a factor of 4; that is, δaμ ˜ 16 × 10-11, a relative uncertainty of 140 ppb. The method follows the same magic-momentum storage ring concept used at BNL, and pioneered previously at CERN, but muon beam preparation, storage ring internal hardware, field measuring equipment, and detector and electronics systems are all new or upgraded significantly. In contrast, J-PARC E34 will employ a novel approach based on injection of an ultra-cold, low-energy, muon beam injected into a small, but highly uniform magnet. Only a small magnetic focusing field is needed to maintain storage, which distinguishes it from CERN, BNL and Fermilab. E34 aims to roughly match the previous BNL precision in their Phase 1 installation.

  18. One-Piece Faraday Generator: A Paradoxical Experiment from 1851

    ERIC Educational Resources Information Center

    Crooks, M. J.; And Others

    1978-01-01

    Describes an experiment based on Faraday's one-piece generator, where the rotating disk is replaced by a cylindrical permanent magnet. Explains the apparent paradox that an observer in an inertial frame could measure his absolute velocity. (GA)

  19. Synthesis and Characterization of Aldol Condensation Products from Unknown Aldehydes and Ketones: An Inquiry-Based Experiment in the Undergraduate Laboratory

    ERIC Educational Resources Information Center

    Angelo, Nicholas G.; Henchey, Laura K.; Waxman, Adam J.; Canary, James W.; Arora, Paramjit S.; Wink, Donald

    2007-01-01

    An experiment for the undergraduate chemistry laboratory in which students perform the aldol condensation on an unknown aldehyde and an unknown ketone is described. The experiment involves the use of techniques such as TLC, column chromatography, and recrystallization, and compounds are characterized by [to the first power]H NMR, GC-MS, and FTIR.…

  20. Early utility experience with wind power generation. Volume 1. Summary report. Final report

    SciTech Connect

    McCabe, T.; Henry, G.; Tennis, M.; Goldenblatt, M.

    1984-01-01

    This report is one of three presenting the results of EPRI Research Project 1590-1, Evaluation of Electric Utility Experience with Wind Power Generation. The objective of this project was to develop an improved understanding of wind power generation, in particular the process a utility must undergo to initiate and carry out a wind turbine project. The primary tasks of RP1590-1 were to document and evaluate the experience of two utilities with megawatt-scale wind turbine installations from project inception to the first rotation of the wind turbine. This summary report presents in brief form the experiences of two utilities, the Pacific Gas and Electric Company and the Bonneville Power Administration, with wind turbine projects at Solano County, California and Goodnoe Hills, Washington, respectively. All documents and reports pertaining to the experiences with the wind turbine projects were reviewed and excerpts made of the highlights. Gaps in the documentation were filled by talking with appropriate people. Site visits were conducted to monitor current activity. The information obtained was evaluated for its generic relevance and benefit to other utilities. Condensed descriptions of the projects, a comparison of the projects, and highlights of the utilities' experiences are presented. Some of the insights which might benefit other utility wind programs are identified.

  1. Generation of maximally entangled states of a Bose-Einstein condensate and Heisenberg-limited phase resolution

    SciTech Connect

    Gerry, Christopher C.; Campos, R. A.

    2003-08-01

    We outline a procedure for Heisenberg-limited phase resolution between two Bose-Einstien condensates (BECs) defined as different hyperfine levels. The method involves first establishing a maximally entangled state using the ideas of nonlinear interferometry previously discussed in the optical domain [C. C. Gerry et al., Phys. Rev. A 66, 013804 (2002)]. In the case of the condensates, the nonlinear interactions are realized by the interatomic interactions within each condensate. Quarter cycle Raman pulses between hyperfine levels act as beam splitters. Parity measurements of one of the components of the BEC resolve the phase at the Heisenberg limit. We point out that parity measurements can be made by coupling the mode of interest with a third condensate where both components evolve under nonlinear interatomic interactions. After another Raman pulse, the components are populated according to parity. One need only determine which component is populated to determine the parity.

  2. Improving Vortex Generators to Enhance the Performance of Air-Cooled Condensers in a Geothermal Power Plant

    SciTech Connect

    Manohar S. Sohal

    2005-09-01

    This report summarizes work at the Idaho National Laboratory to develop strategies to enhance air-side heat transfer in geothermal air-cooled condensers such that it should not significantly increase pressure drop and parasitic fan pumping power. The work was sponsored by the U.S. Department of Energy, NEDO (New Energy and Industrial Technology Development Organization) of Japan, Yokohama National University, and the Indian Institute of Technology, Kanpur, India. A combined experimental and numerical investigation was performed to investigate heat transfer enhancement techniques that may be applicable to largescale air-cooled condensers such as those used in geothermal power applications. A transient heat transfer visualization and measurement technique was employed in order to obtain detailed distributions of local heat transfer coefficients on model fin surfaces. Pressure drop measurements were obtained for a variety of tube and winglet configurations using a single-channel flow apparatus that included four tube rows in a staggered array. Heat transfer and pressure drop measurements were also acquired in a separate multiple-tube row apparatus in the Single Blow Test Facility. In addition, a numerical modeling technique was developed to predict local and average heat transfer for these low-Reynolds number flows, with and without winglets. Representative experimental and numerical results were obtained that reveal quantitative details of local finsurface heat transfer in the vicinity of a circular tube with a single delta winglet pair downstream of the cylinder. Heat transfer and pressure-drop results were obtained for flow Reynolds numbers based on channel height and mean flow velocity ranging from 700 to 6500. The winglets were of triangular (delta) shape with a 1:2 or 1:3 height/length aspect ratio and a height equal to 90% of the channel height. Overall mean fin-surface heat transfer results indicate a significant level of heat transfer enhancement (in terms of

  3. Non-condensable gas effects in ROSA/AP600 small-break LOCA experiments

    SciTech Connect

    Nakamura, Hideo; Kukita, Yutaka; Shaw, R.A.; Schultz, R.R.

    1996-06-01

    Integral experiments simulating the postulated accidents in the Westinghouse AP600 reactor have been conducted using the ROSA-V Large Scale Test Facility (LSTF). These experiments allowed the N{sub 2} gas for the pressurization of accumulator tanks to enter the primary system after the depletion of the tank water inventory. The gas migrated into the Passive Residual Heat Removal (PRHR) system heat exchanger tubes and into the Core Makeup Tanks (CMTs), and influenced the performance of these components which are unique to the AP600 reactor. Specifically, the PRHR was disabled soon after the N{sub 2} gas discharge in most of the experiments, although the core decay power was removed well by the steam discharge through the Automatic Depressurization System (ADS) after the PRHR was disabled. The N{sub 2} gas ingress into the CMTs occurred in the experiments with relatively large breaks ({ge} 2 inch in equivalent diameter), and contributed to a smooth draindown of the CMT inventory into the primary system.

  4. Tentative experiment for generating low-photon-energy quasi-x-ray lasers using a capillary

    NASA Astrophysics Data System (ADS)

    Sato, Eiichi; Toriyabe, Hiroyuki; Awaji, Wataru; Hayasi, Yasuomi; Ichimaru, Toshio; Usuki, Tatsumi; Sato, Koetsu; Ojima, Hidenori; Takayama, Kazuyoshi; Tamakawa, Yoshiharu

    2001-04-01

    The tentative experiment for producing low-photon-energy quasi-x-ray laser using a capillary is described. This flash x-ray generator was improved in order to increase the x-ray intensity and to produce high-intensity characteristic x-rays by forming the linear plasma x-ray source. The generator consists of a high-voltage power supply, a polarity-inversion ignitron pulse generator, a turbo-molecular pump, and a radiation tube with a capillary. A high-voltage condenser of 0.2 (mu) F in the pulse generator is charged up to 20 kV by the power supply, and the electric charges in the condenser are discharged to the capillary in the tube after closing the ignitron. In the present work, the chamber is evacuated by the pump with a pressure of about 1 mPa, and the carbon anode and cathode electrodes are employed to produce K(alpha) characteristic x-rays. The diameter and the length of the ferrite capillary are 2.0 and 29 mm, respectively, and both the cathode voltage and the discharge current displayed damped oscillations. The peak values of the voltage and current increased when the charging voltage was increased, and their maximum values were -9.9 kV and 4.4 kA, respectively. The pulse durations of the x-rays were nearly equivalent to those of the damped oscillations in the voltage and current, and their values were less than 20 microseconds. In the spectrum measurement, we observed the carbon K(alpha) line.

  5. Reduced gravity boiling and condensing experiments simulated with the COBRA/TRAC computer code

    SciTech Connect

    Cuta, J.M.; Krotiuk, W.J.

    1988-02-01

    It is being recognized that there does not currently exist an adequate understanding of flow and heat transfer behavior in reduced- and zero-gravity. There is not a sufficient experimental fluid-thermal data base to develop design correlations for two-phase pressure losses, heat transfer coefficients, and critical heat flux limits in systems proposed for advanced power sources, propulsion, and other thermal management systems in space. Pacific Northwest Laboratory (PNL), is the lead laboratory for thermal hydraulics in the Department of Energy's Multimegawatt Space Power Program, and has the responsibility of developing microgravity thermal-hydraulic analysis capabilities for application to space nuclear power systems. In support of this program, PNL has performed a series of reduced-gravity two-phase flow experiments in the NASA KC-135 aircraft. The objective of the experiment was to supply basic thermal-hydraulic information that could be used in development of analytical design tools. 6 refs., 23 figs., 4 tabs.

  6. Geothermal steam condensate reinjection

    NASA Technical Reports Server (NTRS)

    Chasteen, A. J.

    1974-01-01

    Geothermal electric generating plants which use condensing turbines and generate and excess of condensed steam which must be disposed of are discussed. At the Geysers, California, the largest geothermal development in the world, this steam condensate has been reinjected into the steam reservoir since 1968. A total of 3,150,000,000 gallons of steam condensate has been reinjected since that time with no noticeable effect on the adjacent producing wells. Currently, 3,700,000 gallons/day from 412 MW of installed capacity are being injected into 5 wells. Reinjection has also proven to be a satisfactory method of disposing of geothermal condensate a Imperial Valley, California, and at the Valles Caldera, New Mexico.

  7. Status of power generation experiments in the NASA Lewis closed cycle MHD facility

    NASA Technical Reports Server (NTRS)

    Sovie, R. J.; Nichols, L. D.

    1971-01-01

    The design and operation of the closed cycle MHD facility is discussed and results obtained in recent experiments are presented. The main components of the facility are a compressor, recuperative heat exchanger, heater, nozzle, MHD channel with 28 pairs of thoriated tungsten electrodes, cesium condenser, and an argon cooler. The facility has been operated at temperatures up to 2100 K with a cesium-seeded argon working fluid. At low magnetic field strengths, the open circuit voltage, Hall voltage and short circuit current obtained are 90, 69, and 47 percent of the theoretical equilibrium values, respectively. Comparison of this data with a wall and boundary layer leakage theory indicates that the generator has shorting paths in the Hall direction.

  8. Quench dynamics in Bose-Einstein condensates in the presence of a bath: Theory and experiment

    NASA Astrophysics Data System (ADS)

    Rançon, A.; Hung, Chen-Lung; Chin, Cheng; Levin, K.

    2013-09-01

    In this Rapid Communication we study the transient dynamics of a Bose superfluid subsequent to an interaction quench. Essential for equilibration is a source of dissipation which we include following the approach of Caldeira and Leggett. Here we solve the equations of motion exactly by integrating out an environmental bath. We thereby derive precisely the time dependent density correlation functions with the appropriate analytic and asymptotic properties. The resulting structure factor exhibits the expected damping and thereby differs from that of strict Bogoliubov theory. These damped sound modes, which reflect the physics beyond mean-field approaches, are characterized and the structure factors are found to compare favorably with experiment.

  9. Sauna, sweat and science - quantifying the proportion of condensation water versus sweat using a stable water isotope ((2)H/(1)H and (18)O/(16)O) tracer experiment.

    PubMed

    Zech, Michael; Bösel, Stefanie; Tuthorn, Mario; Benesch, Marianne; Dubbert, Maren; Cuntz, Matthias; Glaser, Bruno

    2015-01-01

    Most visitors of a sauna appreciate the heat pulse that is perceived when water is poured on the stones of a sauna stove. However, probably only few bathers are aware that this pleasant heat pulse is caused by latent heat being released onto our skin due to condensation of water vapour. In order to quantify the proportion of condensation water versus sweat to dripping water of test persons we conducted sauna experiments using isotopically labelled (δ(18)O and δ(2)H) thrown water as tracer. This allows differentiating between 'pure sweat' and 'condensation water'. Two ways of isotope mass balance calculations were applied and yielded similar results for both water isotopes. Accordingly, condensation contributed considerably to dripping water with mean proportions of 52 ± 12 and 54 ± 7% in a sauna experiment in winter semester 2011/12 and 30 ± 13 and 33 ± 6% in a sauna experiment in winter semester 2012/13, respectively, depending on the way of calculating the isotope mass balance. It can be concluded from the results of our dual isotope labelling sauna experiment that it is not all about sweat in the sauna. PMID:26110629

  10. An exclusive event generator for e+e- scan experiments

    NASA Astrophysics Data System (ADS)

    Ping, Rong-Gang

    2014-08-01

    An exclusive event generator is designed for e+e- scan experiments, including initial state radiation effects up to the second order correction. The generator is coded within the framework of BesEvtGen. There are seventy hadronic decay modes available, with effective center-of-mass energy coverage from the two pion mass threshold up to about 6 GeV. The accuracy achieved for the initial state radiation correction reaches the level achieved by the KKMC generator. The uncertainty associated with the calculation of the correction factor to the initial state radiation is dominated by the measurements of the energy-dependent Born cross section.

  11. Internal Energy Dependence of Molecular Condensation Coefficients Determined from Molecular Beam Surface Scattering Experiments

    DOE R&D Accomplishments Database

    Sibener, S. J.; Lee, Y. T.

    1978-05-01

    An experiment was performed which confirms the existence of an internal mode dependence of molecular sticking probabilities for collisions of molecules with a cold surface. The scattering of a velocity selected effusive beam of CCl{sub 4} from a 90 K CC1{sub 4} ice surface has been studied at five translational velocities and for two different internal temperatures. At a surface temperature of 90 K (approx. 99% sticking probability) a four fold increase in reflected intensity was observed for the internally excited (560 K) CC1{sub 4} relative to the room temperature (298 K) CC1{sub 4} at a translational velocity of 2.5 X 10{sup 4} cm/sec. For a surface temperature of 90 K all angular distributions were found to peak 15{sup 0} superspecularly independent of incident velocity.

  12. Schooling Experiences of Central California Indian People across Generations

    ERIC Educational Resources Information Center

    Williams, Tara

    2012-01-01

    This exploratory study took a post-colonialist lens to record, examine and document schooling experiences of California Indian people across several generations representing three Central Valley tribes: the Mono, the Tachi Yokuts of Santa Rosa Rancheria, and the Tule River Tribe. Past and present perceptions of Indian schooling were elicited…

  13. Multifunctional radio-frequency generator for cold atom experiments

    NASA Astrophysics Data System (ADS)

    Wei, Chun-hua; Yan, Shu-hua

    2016-05-01

    We present a low cost radio-frequency (RF) generator suitable for experiments with cold atoms. The RF source achieves a sub-hertz frequency with tunable resolution from 0 MHz to 400 MHz and a maximum output power of 33 dBm. Based on a direct digital synthesizer (DDS) chip, we implement a ramping capability for frequency, amplitude and phase. The system can also operate as an arbitrary waveform generator. By measuring the stability in a duration of 600 s, we find the presented device performs comparably as Agilent33522A in terms of short-term stability. Due to its excellent performance, the RF generator has been already applied to cold atom trapping experiments.

  14. Experiments on H2-O2 MHD power generation

    NASA Astrophysics Data System (ADS)

    Smith, J. M.

    1980-06-01

    MHD power generation experiments utilizing a cesium-seeded H2-O2 working fluid have been carried out using a diverging area Hall duct having an entrance Mach number of 2. The experiments are conducted in a high-field strength cryomagnet facility at field strengths up to 5 tesla. The effects of power takeoff location, axial duct location within the magnetic field, generator loading, B-field strength, and electrode breakdown voltage were investigated. For the operating conditions of these experiments it is found that the power output increases with the square of the B-field and can be limited by choking of the channel or interelectrode voltage breakdown which occurs at Hall fields greater than 50 volts/insulator.

  15. Modeling HEDLA magnetic field generation experiments on laser facilities

    NASA Astrophysics Data System (ADS)

    Fatenejad, M.; Bell, A. R.; Benuzzi-Mounaix, A.; Crowston, R.; Drake, R. P.; Flocke, N.; Gregori, G.; Koenig, M.; Krauland, C.; Lamb, D.; Lee, D.; Marques, J. R.; Meinecke, J.; Miniati, F.; Murphy, C. D.; Park, H.-S.; Pelka, A.; Ravasio, A.; Remington, B.; Reville, B.; Scopatz, A.; Tzeferacos, P.; Weide, K.; Woolsey, N.; Young, R.; Yurchak, R.

    2013-03-01

    The Flash Center is engaged in a collaboration to simulate laser driven experiments aimed at understanding the generation and amplification of cosmological magnetic fields using the FLASH code. In these experiments a laser illuminates a solid plastic or graphite target launching an asymmetric blast wave into a chamber which contains either Helium or Argon at millibar pressures. Induction coils placed several centimeters away from the target detect large scale magnetic fields on the order of tens to hundreds of Gauss. The time dependence of the magnetic field is consistent with generation via the Biermann battery mechanism near the blast wave. Attempts to perform simulations of these experiments using the FLASH code have uncovered previously unreported numerical difficulties in modeling the Biermann battery mechanism near shock waves which can lead to the production of large non-physical magnetic fields. We report on these difficulties and offer a potential solution.

  16. Experiments on H2-O2MHD power generation

    NASA Technical Reports Server (NTRS)

    Smith, J. M.

    1980-01-01

    Magnetohydrodynamic power generation experiments utilizing a cesium-seeded H2-O2 working fluid were carried out using a diverging area Hall duct having an entrance Mach number of 2. The experiments were conducted in a high-field strength cryomagnet facility at field strengths up to 5 tesla. The effects of power takeoff location, axial duct location within the magnetic field, generator loading, B-field strength, and electrode breakdown voltage were investigated. For the operating conditions of these experiments, it is found that the power output increases with the square of the B-field and can be limited by choking of the channel or interelectrode voltage breakdown which occurs at Hall fields greater than 50 volts/insulator. Peak power densities of greater than 100 MW/cu M were achieved.

  17. Resonant infrared laser-induced desorption of methane condensed on NaCl(100): isotope mixture experiments.

    PubMed

    Redlich, Britta; Zacharias, Helmut; Meijer, Gerard; von Helden, Gert

    2006-01-28

    Resonantly enhanced infrared laser-induced desorption of methane condensed on a single-crystal NaCl(100) surface is observed after excitation with the widely tunable infrared laser output of the free-electron laser at the free-electron laser for infrared experiments facility using mass spectroscopic detection and time-of-flight analysis. Desorption of methane is observed only when the exciting light is in resonance with an internal vibrational mode of the molecule. Different intramolecular modes of the three methane isotopologues under study--CH(4), CD(4), and CD(3)H--are excited; the degenerate deformation mode nu(4) is observed for CH(4) and CD(4) at 7.69 and 10.11 microm, respectively, as well as the nu(2) and nu(4) modes of CD(3)H at 7.79, 9.75, and 9.98 microm. The desorption signals for the pure layers of these different methane isotopologues as well as for different mixtures of two of these are investigated as a function of the infrared wavelength and the laser fluence. The desorption behavior for pure and mixed layers is compared and the underlying desorption mechanism is discussed. PMID:16460197

  18. Kibble-Zurek scaling and its breakdown for spontaneous generation of Josephson vortices in Bose-Einstein condensates.

    PubMed

    Su, Shih-Wei; Gou, Shih-Chuan; Bradley, Ashton; Fialko, Oleksandr; Brand, Joachim

    2013-05-24

    Atomic Bose-Einstein condensates confined to a dual-ring trap support Josephson vortices as topologically stable defects in the relative phase. We propose a test of the scaling laws for defect formation by quenching a Bose gas to degeneracy in this geometry. Stochastic Gross-Pitaevskii simulations reveal a -1/4 power-law scaling of defect number with quench time for fast quenches, consistent with the Kibble-Zurek mechanism. Slow quenches show stronger quench-time dependence that is explained by the stability properties of Josephson vortices, revealing the boundary of the Kibble-Zurek regime. Interference of the two atomic fields enables clear long-time measurement of stable defects and a direct test of the Kibble-Zurek mechanism in Bose-Einstein condensation. PMID:23745894

  19. Scanning beam switch experiment for intense rf power generation

    NASA Astrophysics Data System (ADS)

    Humphries, Stanley, Jr.; Babcock, Steven R.; Wilson, J. M.; Adler, Richard J.

    1991-04-01

    1407_57The SBS_1 experiment at Sandia National Laboratories is designed to demonstrate the feasibility of the Scanning Beam Switch for high-power rf generation. The primary application is to pulsed rf linacs and high-frequency induction accelerators. It is expected that the apparatus will generate rf output power exceeding 100 MW at 50 MHz over a 5 microsecond(s) pulse. The device can operate as an oscillator or high gain amplifier. To achieve the capability for long-macropulse and high-duty-cycle operation, SBS_1 uses a large dispenser cathode and vacuum triode input driver.

  20. Studies on pressure response of gas bubbles contributions of condensed droplets in bubbles generated by a uniform nucleation

    NASA Technical Reports Server (NTRS)

    Matsumoto, Y.

    1988-01-01

    The response of a tiny gas bubble under reduced pressure is investigated in its relation to cavitation. Equations of motion are formulated for gas mixtures inside the bubble and numerical calculations performed for several examples. The conclusions are as follows: (1) at the onset of bubble growth, the gas mixture inside it adiabatically expands and the temperature decreases. Condensed droplets appear inside the gas mixture due to a uniform nucleation and the temperature recovers, thus the motion of the bubble is apparently isothermal; (2) the evaporation and condensation coefficient largely affects bubble motions (maximum radius, period and rate of attenuation of the bubble oscillation) including the uniform contraction; (3) the oscillation period of the bubble is longer as the equilibrium bubble radius is larger when the surrounding pressure decreases stepwise. In this circumstance the temperature inside the bubble is kept constant due to condensation evaporation phenomena and is nearly isothermal; and (4) when the surrounding pressure decreases in a stepwise fashion, the critical pressure bubble radius relation becomes closer to that for the isothermal process if the bubble radius is larger than 8 microns.

  1. Automatic content recognition for the next-generation TV experience

    NASA Astrophysics Data System (ADS)

    Lin, Xiaofan

    2012-03-01

    Smart TVs has been introduced. Second, applications running on mobile devices (so called "second-screen apps") have significantly enriched TV watching experience. As an enabler of content-aware TVs and apps, automatic content recognition (ACR) is attracting a lot of attention recently. This paper presents an overview of ACR in this context. It attempts to answer a number of questions: Why do we need ACR for the next generation TV experience? What is the relationship between ACR and existing technologies? What are the unique requirements and challenges on ACR in those applications? What are the typical implementation architectures? It also describes the existing products in this space.

  2. Discovering the Majorana neutrino: The next generation of experiments

    SciTech Connect

    Winslow, L. A.

    2015-07-15

    The discovery of a Majorana neutrino would be revolutionary with far-reaching consequences in both particle physics and cosmology. The only feasible experiments to determine the Majorana nature of the neutrino are searches for neutrinoless double-beta decay. The next generation of double-beta decay experiments are being prepared. The general goal is to search for neutrinoless double-beta decay throughout the parameter space corresponding to the inverted hierarchy for neutrino mass. There are a several strong proposals for how to achieve this goal. The status of these efforts is reviewed.

  3. Condensed Matter Nuclear Science

    NASA Astrophysics Data System (ADS)

    Biberian, Jean-Paul

    2006-02-01

    1. General. A tribute to gene Mallove - the "Genie" reactor / K. Wallace and R. Stringham. An update of LENR for ICCF-11 (short course, 10/31/04) / E. Storms. New physical effects in metal deuterides / P. L. Hagelstein ... [et al.]. Reproducibility, controllability, and optimization of LENR experiments / D. J. Nagel -- 2. Experiments. Electrochemistry. Evidence of electromagnetic radiation from Ni-H systems / S. Focardi ... [et al.]. Superwave reality / I. Dardik. Excess heat in electrolysis experiments at energetics technologies / I. Dardik ... [et al.]. "Excess heat" during electrolysis in platinum/K[symbol]CO[symbol]/nickel light water system / J. Tian ... [et al.]. Innovative procedure for the, in situ, measurement of the resistive thermal coefficient of H(D)/Pd during electrolysis; cross-comparison of new elements detected in the Th-Hg-Pd-D(H) electrolytic cells / F. Celani ... [et al.]. Emergence of a high-temperature superconductivity in hydrogen cycled Pd compounds as an evidence for superstoihiometric H/D sites / A. Lipson ... [et al.]. Plasma electrolysis. Calorimetry of energy-efficient glow discharge - apparatus design and calibration / T. B. Benson and T. O. Passell. Generation of heat and products during plasma electrolysis / T. Mizuno ... [et al.]. Glow discharge. Excess heat production in Pd/D during periodic pulse discharge current in various conditions / A. B. Karabut. Beam experiments. Accelerator experiments and theoretical models for the electron screening effect in metallic environments / A. Huke, K. Czerski, and P. Heide. Evidence for a target-material dependence of the neutron-proton branching ratio in d+d reactions for deuteron energies below 20keV / A. Huke ... [et al.]. Experiments on condensed matter nuclear events in Kobe University / T. Minari ... [et al.]. Electron screening constraints for the cold fusion / K. Czerski, P. Heide, and A. Huke. Cavitation. Low mass 1.6 MHz sonofusion reactor / R. Stringham. Particle detection. Research

  4. CONDENSATION CAN

    DOEpatents

    Booth, E.T. Jr.; Pontius, R.B.; Jacobsohn, B.A.; Slade, C.B.

    1962-03-01

    An apparatus is designed for condensing a vapor to a solid at relatively low back pressures. The apparatus comprises a closed condensing chamber, a vapor inlet tube extending to the central region of the chamber, a co-axial tubular shield surrounding the inlet tube, means for heating the inlet tube at a point outside the condensing chamber, and means for refrigeratirg the said chamber. (AEC)

  5. Utility experience with two demonstration wind turbine generators

    NASA Technical Reports Server (NTRS)

    Wehrey, M. C.

    1982-01-01

    Edison has committed 360 MW of nameplate generating capacity to wind energy by year 1990 in its long-range generation plan. To reach this goal the Company's wind energy program focuses on three areas: the continuous evaluation of the wind resource, the hands-on demonstration of wind turbine generators (WTG) and an association with wind park developers. Two demonstration WTGs have been installed and operated at Edison's Wind Energy Center near Palm Springs, California: a 3 MW horizontal axis Bendix/Schachle WTG and a 500 kW vertical axis Alcoa WTG. They are part of a one to two year test program during which the performance of the WTGs will be evaluated, their system operation and environmental impact will be assessed and the design criteria of future WTGs will be identified. Edison's experience with these two WTGs is summarized and the problems encountered with the operation of the two machines are discussed.

  6. Experience in the repair of steam generator auxiliary feedwater nozzle

    SciTech Connect

    Chao, K.K.N.

    1996-12-01

    The auxiliary feedwater nozzle is quite often subjected to more thermal stress cycles and other loading mechanisms during their service life than the material was designed and fabricated for at the nozzle of the earlier steam generators in many nuclear plants. During plant operation, the auxiliary feedwater nozzle outlet is exposed to the hot steam from the generator side, while the auxiliary feedwater piping which contains subcooled water from the inlet often induces water hammer as a result of the steam-water mixing phenomena. The thermal cycles and the steam bubble collapse at the nozzle may cause cracking in the nozzle liner and interior surface of the nozzle, and subsequently results in structural damage to the steam generator. This presentation is intended to share the lessons learned from the evaluation of the nozzle condition and the subsequent modification and repair made to the auxiliary feedwater nozzle at the Palisades Nuclear Plant. Other nuclear plant owners may benefit from this experience.

  7. Options for a next-generation spheromak physics experiment

    NASA Astrophysics Data System (ADS)

    Hooper, E. B.; Cohen, B. I.; Hill, D. N.; McLean, H. S.; Romero-Talamás, C. A.; Wood, R. D.

    2006-10-01

    SSPX experiments and resistive MHD modeling suggest options for a next-generation experiment. Magnetic fluctuations are now <1% when the q-profile does not cross low-order rational surfaces in the spheromak core, yielding good energy confinement.^1 Plasma current and magnetic field decay slowly; initial experiments suggest that the they can be rebuilt periodically by high current pulses.^2 Modeling predicts that flux amplification, typically 2-3 in SSPX, can be increased to >50 by actively reducing the bias (``ABR'') after spheromak formation, reducing edge ohmic losses proportionally. ABR is also predicted to improve stability and energy confinement. Neutral-beam experiments planned for SSPX^3 may provide a path to hotter plasmas. Next-generation spheromak geometries and scenarios building on these results are described to improve plasma parameters, explore additional stability control, and examine other physics issues. Work supported by U.S. DOE under Contract No. W-7405-ENG-48 at UC LLNL. ^1H. S. McLean, et al., Phys. Plasmas 13, 056105 (2006). ^2S. Woodruff, et al., Phys. Rev. Letters 93, 205002 (2004). ^3D..N. Hill, et al., this meeting.

  8. FLASH magnetohydrodynamic simulations of shock-generated magnetic field experiments

    NASA Astrophysics Data System (ADS)

    Tzeferacos, P.; Fatenejad, M.; Flocke, N.; Gregori, G.; Lamb, D. Q.; Lee, D.; Meinecke, J.; Scopatz, A.; Weide, K.

    2012-12-01

    We report the results of benchmark FLASH magnetohydrodynamic (MHD) simulations of experiments conducted by the University of Oxford High Energy Density Laboratory Astrophysics group and its collaborators at the Laboratoire pour l'Utilisation des Lasers Intenses (LULI). In these experiments, a long-pulse laser illuminates a target in a chamber filled with Argon gas, producing shock waves that generate magnetic fields via the Biermann battery mechanism. We first outline the implementation of 2D cylindrical geometry in the unsplit MHD solver in FLASH and present results of verification tests. We then describe the results of benchmark 2D cylindrical MHD simulations of the LULI experiments using FLASH that explore the impact of external fields along with the possibility of magnetic field amplification by turbulence that is associated with the shock waves and that is induced by a grid placed in the gas-filled chamber.

  9. Bose-Einstein condensation in a dilute gas: the first 70 years and some recent experiments (Nobel Lecture).

    PubMed

    Cornell, Eric A; Wieman, Carl E

    2002-06-17

    Bose-Einstein condensates of dilute gases offer a rich field to study fundamental quantum-mechanical processes, manipulation of the speed at which light propogates, observation of atomic pair-formation and superfluidity, or even simulating white dwarf stars. Still more radical applications are on the horizon. However, their initial creation was a masterpiece of experimental physics. After an initial process of laser cooling (which itself won its developers the 1997 Nobel Prize), atoms in a magnetic-optical trap must be safely transferred into a purely magnetic trap, where the condensation process begins at 170 nK and 20 nK a pure condensate of 2000 atoms could be created. More astonishingly, Wieman and Cornell showed these low temperatures could be achieved in "bench scale" equipment rather than the massive pieces normally demanded by cryoscience. For their 1995 discovery of this new state of matter, they were awarded the 2001 Nobel Prize in Physics. PMID:12465486

  10. Study of experiments on condensation of nitrogen by homogeneous nucleation at states modelling those on the national transonic facility

    NASA Technical Reports Server (NTRS)

    Wegener, P. P.

    1980-01-01

    A cryogenic wind tunnel is based on the twofold idea of lowering drive power and increasing Reynolds number by operating with nitrogen near its boiling point. There are two possible types of condensation problems involved in this mode of wind tunnel operation. They concern the expansion from the nozzle supply to the test section at relatively low cooling rates, and secondly the expansion around models in the test section. This secondary expansion involves higher cooling rates and shorter time scales. In addition to these two condensation problems it is not certain what purity of nitrogen can be achieved in a large facility. Therefore, one cannot rule out condensation processes other than those of homogeneous nucleation.

  11. Experiments with Test Case Generation and Runtime Analysis

    NASA Technical Reports Server (NTRS)

    Artho, Cyrille; Drusinsky, Doron; Goldberg, Allen; Havelund, Klaus; Lowry, Mike; Pasareanu, Corina; Rosu, Grigore; Visser, Willem; Koga, Dennis (Technical Monitor)

    2003-01-01

    Software testing is typically an ad hoc process where human testers manually write many test inputs and expected test results, perhaps automating their execution in a regression suite. This process is cumbersome and costly. This paper reports preliminary results on an approach to further automate this process. The approach consists of combining automated test case generation based on systematically exploring the program's input domain, with runtime analysis, where execution traces are monitored and verified against temporal logic specifications, or analyzed using advanced algorithms for detecting concurrency errors such as data races and deadlocks. The approach suggests to generate specifications dynamically per input instance rather than statically once-and-for-all. The paper describes experiments with variants of this approach in the context of two examples, a planetary rover controller and a space craft fault protection system.

  12. Condensation of water vapor in rarefaction waves. I - Homogeneous nucleation

    NASA Technical Reports Server (NTRS)

    Sislian, J. P.; Glass, I. I.

    1976-01-01

    A detailed theoretical investigation has been made of the condensation of water vapor/carrier gas mixtures in the nonstationary rarefaction wave generated in a shock tube. It is assumed that condensation takes place by homogeneous nucleation. The equations of motion together with the nucleation rate and the droplet growth equations were solved numerically by the method of characteristics and Lax's method of implicit artificial viscosity. It is found that, for the case considered, the condensation wave formed by the collapse of the metastable nonequilibrium state is followed by a shock wave generated by the intersection of characteristics of the same family. The expansion is practically isentropic up to the onset of condensation. The condensation front accelerates in the x,t plane. The results of the computations for a chosen case of water vapor/nitrogen mixture are presented by plotting variations of pressure, nucleation rate, number density of critical clusters, and condensate mass-fraction along three particle paths. Some consideration is given to homogeneous condensation experiments conducted in a shock tube. Although a direct comparison of the present theoretical work and these experiments is not possible, several worthwhile interpretative features have resulted nevertheless.

  13. Results of railgun experiments powered by magnetic flux compression generators

    SciTech Connect

    Hawke, R.S.; Brooks, A.L.; Deadrick, F.J.; Scudder, J.K.; Fowler, C.M.; Caird, R.S.; Peterson, D.R.

    1980-10-24

    Researchers from LLNL and LANSL initiated a joint railgun research and development program to explore the potential of electromagnetic railguns to accelerate projectiles to hypervelocities. The effort was intended to determine experimentally the limits of railgun operation, to verify calculations of railgun performance, and to establish a data base at megampere currents. The program has led to the selection of a particular magnetic flux compression generator (MFCG) design for a set of initial experiments and to the design of small- and large-square bore railguns to match the expected MFCG power profile. The bore sizes are 12.7 and 50 mm, respectively. The design of the railguns and the diagnostic and data reduction techniques, followed by the results of eight experiments with the two railgun types are presented.

  14. Results of railgun experiments powered by magnetic flux compression generators

    SciTech Connect

    Hawke, R.S.; Brooks, A.L.; Deadrick, J.; Scudder, J.K.; Fowler, C.M.; Caird, R.S.; Peterson, D.R.

    1981-03-16

    Researchers from the Lawrence Livermore National Laboratory and the Los Alamos National Laboratory initiated a joint railgun research and development program to explore the potential of electromagnetic railguns to accelerate projectiles to hypervelocities. The effort was intended to (1) determine experimentally the limits of railgun operation; (2) verify calculations of railgun performance; and (3) establish a data base at megampere currents. The program has led to the selection of a particular magnetic flux compression generator (MFCG) design for a set of initial experiments and the design of small- and large-square-bore railguns to match the expected MFCG power profile. The bore sizes are 12.7 and 50 mm, respectively. In this paper, the design of the railguns and the diagnostic and data reduction techniques, followed by the results of eight experiments with the two railgun types, are presented.

  15. The generation of crystal defects in Ge-on-insulator (GOI) layers in the Ge-condensation process

    NASA Astrophysics Data System (ADS)

    Nakaharai, S.; Tezuka, T.; Hirashita, N.; Toyoda, E.; Moriyama, Y.; Sugiyama, N.; Takagi, S.

    2007-01-01

    The formation process of crystal defects in a Ge-on-insulator (GOI) layer fabricated by oxidizing a SiGe-on-insulator (SGOI) layer, known as the Ge-condensation technique, is studied systematically. It is found that the crystal defects in the GOI layer are threading dislocations and microtwins that are formed mainly in the Ge fraction range larger than ~0.5. Also, when the Ge fraction reaches ~1 and the GOI layer is formed, the density of microtwins significantly decreases and their width considerably increases. The relaxation of compressive strain, observed in SGOI and GOI layers, is not attributable to the formation of the microtwins, but to the perfect dislocations that cannot be detected as defects in the lattice image.

  16. Reproducibility of Variant Calls in Replicate Next Generation Sequencing Experiments

    PubMed Central

    Qi, Yuan; Liu, Xiuping; Liu, Chang-gong; Wang, Bailing; Hess, Kenneth R.; Symmans, W. Fraser; Shi, Weiwei; Pusztai, Lajos

    2015-01-01

    Nucleotide alterations detected by next generation sequencing are not always true biological changes but could represent sequencing errors. Even highly accurate methods can yield substantial error rates when applied to millions of nucleotides. In this study, we examined the reproducibility of nucleotide variant calls in replicate sequencing experiments of the same genomic DNA. We performed targeted sequencing of all known human protein kinase genes (kinome) (~3.2 Mb) using the SOLiD v4 platform. Seventeen breast cancer samples were sequenced in duplicate (n=14) or triplicate (n=3) to assess concordance of all calls and single nucleotide variant (SNV) calls. The concordance rates over the entire sequenced region were >99.99%, while the concordance rates for SNVs were 54.3-75.5%. There was substantial variation in basic sequencing metrics from experiment to experiment. The type of nucleotide substitution and genomic location of the variant had little impact on concordance but concordance increased with coverage level, variant allele count (VAC), variant allele frequency (VAF), variant allele quality and p-value of SNV-call. The most important determinants of concordance were VAC and VAF. Even using the highest stringency of QC metrics the reproducibility of SNV calls was around 80% suggesting that erroneous variant calling can be as high as 20-40% in a single experiment. The sequence data have been deposited into the European Genome-phenome Archive (EGA) with accession number EGAS00001000826. PMID:26136146

  17. UPTF-TRAM experiments for SBLOCA: Evaluation of condensation processes in TRAM tests A6 and A7

    SciTech Connect

    Sonneburg, H.G.; Tuunanen, J.; Palazov, V.V.

    1995-09-01

    The investigation of thermal-hydraulic phenomena related to reactor transients with accident management measures is the goal of the TRansient and accident Management (TRAM) experimental programme being carried out at the Upper Plenum Test Facility (UPTF) at Mannheim (Germany). These experimental investigations and test analyses are funded by the German Federal Minister for Research and Technology (BMFT). The UPTF simulates these phenomena in a 1:1 such relative to the dimension of a PWR. Condensation of steam during Emergency Core Cooling (ECC) water injection from accumulators into the primary system is one of the phenomena studied within the accumulators into the primary system is one of the phenomena studied within the TRAM programme. This phenomenon partly controls the efficiency of accumulator injection if the high pressure safety systems fail. Beside this, the condensation within the nitrogen inside the accumulator for a certain period controls the pressure development inside the accumulator. Thus, both condensation phenomena determine the ECC flow rate delivered to the primary system. Concerning the condensation inside the primary system, this is also of safety relevance in the case of Pressurized Thermal Shock (PTS) during cold leg injection.

  18. Recent operating experiences with steam generators in Japanese NPPs

    SciTech Connect

    Yashima, Seiji

    1997-02-01

    In 1994, the Genkai-3 of Kyushu Electric Power Co., Inc. and the Ikata-3 of Shikoku Electric Power Co., Inc. started commercial operation, and now 22 PWR plants are being operated in Japan. Since the first PWR plant now 22 PWR plants are being operated in was started to operate, Japanese PWR plants have had an operating experience of approx. 280 reactor-years. During that period, many tube degradations have been experienced in steam generators (SGs). And, in 1991, the steam generator tube rupture (SGTR) occurred in the Mihama-2 of Kansai Electric Power Co., Inc. However, the occurrence of tube degradation of SGs has been decreased by the instructions of the MITI as regulatory authorities, efforts of Electric Utilities, and technical support from the SG manufacturers. Here the author describes the recent SGs in Japan about the following points. (1) Recent Operating Experiences (2) Lessons learned from Mihama-2 SGTR (3) SG replacement (4) Safety Regulations on SG (5) Research and development on SG.

  19. Final Report for Intravenous Fluid Generation (IVGEN) Spaceflight Experiment

    NASA Technical Reports Server (NTRS)

    McQuillen, John B.; McKay, Terri L.; Griffin, DeVon W.; Brown, Dan F.; Zoldak, John T.

    2011-01-01

    NASA designed and operated the Intravenous Fluid Generation (IVGEN) experiment onboard the International Space Station (ISS), Increment 23/24, during May 2010. This hardware was a demonstration experiment to generate intravenous (IV) fluid from ISS Water Processing Assembly (WPA) potable water using a water purification technique and pharmaceutical mixing system. The IVGEN experiment utilizes a deionizing resin bed to remove contaminants from feedstock water to a purity level that meets the standards of the United States Pharmacopeia (USP), the governing body for pharmaceuticals in the United States. The water was then introduced into an IV bag where the fluid was mixed with USP-grade crystalline salt to produce USP normal saline (NS). Inline conductivity sensors quantified the feedstock water quality, output water purity, and NS mixing uniformity. Six 1.5-L bags of purified water were produced. Two of these bags were mixed with sodium chloride to make 0.9 percent NS solution. These two bags were returned to Earth to test for compliance with USP requirements. On-orbit results indicated that all of the experimental success criteria were met with the exception of the salt concentration. Problems with a large air bubble in the first bag of purified water resulted in a slightly concentrated saline solution of 117 percent of the target value of 0.9 g/L. The second bag had an inadequate amount of salt premeasured into the mixing bag resulting in a slightly deficient salt concentration of 93.8 percent of the target value. The USP permits a range from 95 to 105 percent of the target value. The testing plans for improvements for an operational system are also presented.

  20. Computer-Generated Ovaries to Assist Follicle Counting Experiments

    PubMed Central

    Skodras, Angelos; Marcelli, Gianluca

    2015-01-01

    Precise estimation of the number of follicles in ovaries is of key importance in the field of reproductive biology, both from a developmental point of view, where follicle numbers are determined at specific time points, as well as from a therapeutic perspective, determining the adverse effects of environmental toxins and cancer chemotherapeutics on the reproductive system. The two main factors affecting follicle number estimates are the sampling method and the variation in follicle numbers within animals of the same strain, due to biological variability. This study aims at assessing the effect of these two factors, when estimating ovarian follicle numbers of neonatal mice. We developed computer algorithms, which generate models of neonatal mouse ovaries (simulated ovaries), with characteristics derived from experimental measurements already available in the published literature. The simulated ovaries are used to reproduce in-silico counting experiments based on unbiased stereological techniques; the proposed approach provides the necessary number of ovaries and sampling frequency to be used in the experiments given a specific biological variability and a desirable degree of accuracy. The simulated ovary is a novel, versatile tool which can be used in the planning phase of experiments to estimate the expected number of animals and workload, ensuring appropriate statistical power of the resulting measurements. Moreover, the idea of the simulated ovary can be applied to other organs made up of large numbers of individual functional units. PMID:25812007

  1. Free convective condensation in a vertical enclosure

    SciTech Connect

    Fox, R.J.; Peterson, P.F.; Corradini, M.L.; Pernsteiner, A.P.

    1995-09-01

    Free convective condensation in a vertical enclosure was studied numerically and the results were compared with experiments. In both the numerical and experimental investigations, mist formation was observed to occur near the cooling wall, with significant droplet concentrations in the bulk. Large recirculation cells near the end of the condensing section were generated as the heavy noncondensing gas collecting near the cooling wall was accelerated downward. Near the top of the enclosure the recirculation cells became weaker and smaller than those below, ultimately disappearing near the top of the condenser. In the experiment the mist density was seen to be highest near the wall and at the bottom of the condensing section, whereas the numerical model predicted a much more uniform distribution. The model used to describe the formation of mist was based on a Modified Critical Saturation Model (MCSM), which allows mist to be generated once the vapor pressure exceeds a critical value. Equilibrium, nonequilibrium, and MCSM calculations were preformed, showing the experimental results to lie somewhere in between the equilibrium and nonequilibrium predictions of the numerical model. A single adjustable constant (indicating the degree to which equilibrium is achieved) is used in the model in order to match the experimental results.

  2. Compact submicrosecond, high current generator for wire explosion experiments

    NASA Astrophysics Data System (ADS)

    Aranchuk, L. E.; Chuvatin, A. S.; Larour, J.

    2004-01-01

    The PIAF generator was designed for low total energy and high energy density experiments with liners, X-pinch or fiber Z-pinch loads. These studies are of interest for such applications as surface and material science, microscopy of biological specimens, lithography of x-ray sensitive resists, and x-ray backlighting of pulsed-power plasmas. The generator is based on an RLC circuit that includes six NWL 180 nF-50 kV capacitors that store up to 1.3 kJ. The capacitors are connected in parallel to a single multispark switch designed to operate at atmospheric pressure. The switch allows reaching a time delay between the trigger pulse and the current pulse of less than 80 ns and has jitter of 6 ns. The total inductance without a load compartment was optimized to be as low as 16 nH, which leads to extremely low impedance of ˜0.12 Ω. A 40 kV initial voltage provides 250 kA maximum current in a 6 nH inductive load with a 180 ns current rise time. PIAF has dimensions of 660×660×490 mm and weight of less than 100 kg, thus manifesting itself as robust, simple to operate, and cost effective. A description of the PIAF generator and the initial experimental results on PIAF with an X-pinch type load are reported. The generator was demonstrated to operate successfully with an X-pinch type load. The experiments first started with investigation of the previously unexplored X-pinch conduction time range, 100 ns-1 μs. A single short radiation pulse was obtained that came from a small, point-like plasma. The following x-ray source characteristics were achieved: typical hot spot size of 50-100 μm, radiation pulse duration of 1.5-2 ns, and radiation yield of about 250-500 mJ in the softer spectral range (hν⩾700 eV) and 50-100 mJ in the harder one (hν⩾1 keV). These results provide the potential for further application of this source, such as use as a backlight diagnostic tool.

  3. Modelling hot electron generation in short pulse target heating experiments

    NASA Astrophysics Data System (ADS)

    Sircombe, N. J.; Hughes, S. J.

    2013-11-01

    Target heating experiments planned for the Orion laser facility, and electron beam driven fast ignition schemes, rely on the interaction of a short pulse high intensity laser with dense material to generate a flux of energetic electrons. It is essential that the characteristics of this electron source are well known in order to inform transport models in radiation hydrodynamics codes and allow effective evaluation of experimental results and forward modelling of future campaigns. We present results obtained with the particle in cell (PIC) code EPOCH for realistic target and laser parameters, including first and second harmonic light. The hot electron distributions are characterised and their implications for onward transport and target heating are considered with the aid of the Monte-Carlo transport code THOR.

  4. Jefferson Lab injector development for next generation parity violation experiments

    NASA Astrophysics Data System (ADS)

    Grames, J.; Hansknect, J.; Poelker, M.; Suleiman, R.

    2011-11-01

    To meet the challenging requirements of next generation parity violation experiments at Jefferson Lab, the Center for Injectors and Sources is working on improving the parity-quality of the electron beam. These improvements include new electron photogun design and fast helicity reversal of the Pockels Cell. We proposed and designed a new scheme for slow helicity reversal using a Wien Filter and two Solenoids. This slow reversal complements the insertable half-wave plate reversal of the laser-light polarization by reversing the electron beam polarization at the injector while maintaining a constant accelerator configuration. For position feedback, fast air-core magnets located in the injector were commissioned and a new scheme for charge feedback is planned.

  5. Solar wind-generated current in the Lunar Dust Experiment

    NASA Astrophysics Data System (ADS)

    Xie, Lianghai; Zhang, Xiaoping; Zheng, Yongchun; Guo, Dawei

    2016-04-01

    Measurements from the Lunar Dust Experiment (LDEX) show that the current associated with lofted lunar dust lacks an altitude dependence, implying that the current may come from other sources. Here we present some evidences for solar wind (SW)-generated current. Direct SW influx on the nightside can cause a large current, and the backscattered energetic neutral atoms (ENAs) on the dayside can bring a good correlation between the current and SW density. It is found that the current favors a lower SW speed and a smaller SW incident angle, but the dependences are also affected by the solar zenith angle (SZA) and the scattering function of ENAs. Picked-up ions can enhance the current when the angle between the convection electric field and LDEX's normal is larger than 90°. But when the angle is smaller than 90°, the enhancement is negligible.

  6. Generating a soliton splash through variational modelling and experiments

    NASA Astrophysics Data System (ADS)

    Kalogirou, Anna; Bokhove, Onno

    2015-11-01

    Mathematical modelling of water waves in tanks with wave generators is demonstrated by investigating variational methods asymptotically and numerically. A reduced potential flow water wave model is derived using variational techniques, which is based on the assumptions of waves with small amplitude and large wavelength. This model consists of a set of modified Benney-Luke equations describing the deviation from the still water surface η (x , y , t) and the bottom potential Φ (x , y , t) , and includes a time-dependent gravitional potential mimicking a removable ``sluice gate''. The asymptotic model is solved numerically using the automated system Firedrake. In particular, a (dis)continuous Galerkin finite element method is used, together with symplectic integrators for the time discretisation. As a validation, the numerical results are compared to a soliton splash experiment in a long water channel with a contraction at its end, resulting after a sluice gate is removed at a finite time.

  7. New generation of cryogen free advanced superconducting magnets for neutron scattering experiments

    NASA Astrophysics Data System (ADS)

    Kirichek, O.; Brown, J.; Adroja, D. T.; Manuel, P.; Kouzmenko, G.; Bewley, R. I.; Wotherspoon, R.

    2012-12-01

    Recent advances in superconducting technology and cryocooler refrigeration have resulted in a new generation of advanced superconducting magnets for neutron beam applications. These magnets have outstanding parameters such as high homogeneity and stability at highest magnetic fields possible, a reasonably small stray field, low neutron scattering background and larger exposure to neutron detectors. At the same time the pulse tube refrigeration technology provides a complete re-condensing regime which allows to minimise the requirements for cryogens without introducing additional noise and mechanical vibrations. The magnets can be used with dilution refrigerator insert which expands the temperature range from 20mK to 300K. Here we are going to present design, test results and the operational data of the 14T magnet for neutron diffraction and the 9T wide angle chopper magnet for neutron spectroscopy developed by Oxford Instruments in collaboration with ISIS neutron source. First scientific results obtained from the neutron scattering experiments with these magnets are also going to be discussed.

  8. Condensation polyimides

    NASA Technical Reports Server (NTRS)

    Hergenrother, P. M.

    1989-01-01

    Polyimides belong to a class of polymers known as polyheterocyclics. Unlike most other high temperature polymers, polyimides can be prepared from a variety of inexpensive monomers by several synthetic routes. The glass transition and crystalline melt temperature, thermooxidative stability, toughness, dielectric constant, coefficient of thermal expansion, chemical stability, mechanical performance, etc. of polyimides can be controlled within certain boundaries. This versatility has permitted the development of various forms of polyimides. These include adhesives, composite matrices, coatings, films, moldings, fibers, foams and membranes. Polyimides are synthesized through both condensation (step-polymerization) and addition (chain growth polymerization) routes. The precursor materials used in addition polyimides or imide oligomers are prepared by condensation method. High molecular weight polyimide made via polycondensation or step-growth polymerization is studied. The various synthetic routes to condensation polyimides, structure/property relationships of condensation polyimides and composite properties of condensation polyimides are all studied. The focus is on the synthesis and chemical structure/property relationships of polyimides with particular emphasis on materials for composite application.

  9. Keeping condensers clean

    SciTech Connect

    Wicker, K.

    2006-04-15

    The humble condenser is among the biggest contributors to a steam power plant's efficiency. But although a clean condenser can provide great economic benefit, a dirty one can raise plant heat rate, resulting in large losses of generation revenue and/or unnecessarily high fuel bills. Conventional methods for cleaning fouled tubes range form chemicals to scrapers to brushes and hydro-blasters. This article compares the available options and describes how one power station, Omaha Public Power District's 600 MW North Omaha coal-fired power station, cleaned up its act. The makeup and cooling water of all its five units comes from the Missouri River. 6 figs.

  10. Evaluating vortex generator jet experiments for turbulent flow separation control

    NASA Astrophysics Data System (ADS)

    von Stillfried, F.; Kékesi, T.; Wallin, S.; Johansson, A. V.

    2011-12-01

    Separating turbulent boundary-layers can be energized by streamwise vortices from vortex generators (VG) that increase the near wall momentum as well as the overall mixing of the flow so that flow separation can be delayed or even prevented. In general, two different types of VGs exist: passive vane VGs (VVG) and active VG jets (VGJ). Even though VGs are already successfully used in engineering applications, it is still time-consuming and computationally expensive to include them in a numerical analysis. Fully resolved VGs in a computational mesh lead to a very high number of grid points and thus, computational costs. In addition, computational parameter studies for such flow control devices take much time to set-up. Therefore, much of the research work is still carried out experimentally. KTH Stockholm develops a novel VGJ model that makes it possible to only include the physical influence in terms of the additional stresses that originate from the VGJs without the need to locally refine the computational mesh. Such a modelling strategy enables fast VGJ parameter variations and optimization studies are easliy made possible. For that, VGJ experiments are evaluated in this contribution and results are used for developing a statistical VGJ model.

  11. Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

    NASA Astrophysics Data System (ADS)

    Battaglieri, M.; Briscoe, B. J.; Celentano, A.; Chung, S.-U.; D'Angelo, A.; De Vita, R.; Döring, M.; Dudek, J.; Eidelman, S.; Fegan, S.; Ferretti, J.; Filippi, A.; Fox, G.; Galata, G.; García-Tecocoatzi, H.; Glazier, D. I.; Grube, B.; Hanhart, C.; Hoferichter, M.; Hughes, S. M.; Ireland, D. G.; Ketzer, B.; Klein, F. J.; Kubis, B.; Liu, B.; Masjuan, P.; Mathieu, V.; McKinnon, B.; Mitchel, R.; Nerling, F.; Paul, S.; Peláez, J. R.; Rademacker, J.; Rizzo, A.; Salgado, C.; Santopinto, E.; Sarantsev, A. V.; Sato, T.; Schlüter, T.; [Silva]da Silva, M. L. L.; Stankovic, I.; Strakovsky, I.; Szczepaniak, A.; Vassallo, A.; Walford, N. K.; Watts, D. P.; Zana, L.

    The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopy in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document.

  12. Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

    DOE PAGESBeta

    Battaglieri, Marco; Briscoe, William; Celentano, Andrea; Chung, Suh-Urk; D'Angelo, Annalisa; De Vita, Rafaella; Döring, Michael; Dudek, Jozef; Eidelman, S.; Fegan, Stuart; et al

    2015-01-01

    The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopymore » in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document.« less

  13. Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

    SciTech Connect

    Battaglieri, Marco; Briscoe, William; Celentano, Andrea; Chung, Suh-Urk; D'Angelo, Annalisa; De Vita, Rafaella; Döring, Michael; Dudek, Jozef; Eidelman, S.; Fegan, Stuart; Ferretti, J.; Filippi, A.; Fox, G.; Galata, G.; García-Tecocoatzi, H.; Glazier, Derek; Grube, B.; Hanhart, C.; Hoferichter, M.; Hughes, S. M.; Ireland, David G.; Ketzer, B.; Klein, Franz J.; Kubis, B.; Liu, B.; Masjuan, P.; Mathieu, Vincent; McKinnon, Brian; Mitchel, R.; Nerling, F.; Paul, S.; Peláez, J. R.; Rademacker, J.; Rizzo, Alessandro; Salgado, Carlos; Santopinto, E.; Sarantsev, Andrey V.; Sato, Toru; Schlüter, T.; da Silva, M. L.L.; Stankovic, I.; Strakovsky, Igor; Szczepaniak, Adam; Vassallo, A.; Walford, Natalie K.; Watts, Daniel P.

    2015-01-01

    The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopy in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document.

  14. Optimization of Extreme Ultraviolet Light Source from High Harmonic Generation for Condensed-Phase Core-Level Spectroscopy

    NASA Astrophysics Data System (ADS)

    Lin, Ming-Fu; Verkamp, Max A.; Ryland, Elizabeth S.; Benke, Kristin; Zhang, Kaili; Carlson, Michaela; Vura-Weis, Josh

    2015-06-01

    Extreme ultraviolet (XUV) light source from high-order harmonic generation has been shown to be a powerful tool for core-level spectroscopy. In addition, this light source provides very high temporal resolution (10-18 s to 10-15 s) for time-resolved transient absorption spectroscopy. Most applications of the light source have been limited to the studies of atomic and molecular systems, with technique development focused on optimizing for shorter pulses (i.e. tens of attoseconds) or higher XUV energy (i.e. ~keV range). For the application to general molecular systems in solid and liquid forms, however, the XUV photon flux and stability are highly demanded due to the strong absorption by substrates and solvents. In this case, the main limitation is due to the stability of the high order generation process and the limited bandwidth of the XUV source that gives only discrete even/odd order peaks. Consequently, this results in harmonic artifact noise that overlaps with the resonant signal. In our current study, we utilize a semi-infinite cell for high harmonic generation from two quantum trajectories (i.e. short and long) at over-driven NIR power. This condition, produces broad XUV spectrum without using complicated optics (e.g. hollow-core fibers and double optical gating). This light source allows us to measure the static absorption spectrum of the iron M-edge from a Fe(acac)3 molecular solid film, which shows a resonant feature of 0.01 OD (~2.3% absorption). Moreover, we also investigate how sample roughness affects the static absorption spectrum. We are able to make smooth solar cell precursor materials (i.e. PbI2 and PbBr2) by spin casting and observe iodine (50 eV) and bromine (70 eV) absorption edges in the order of 0.05 OD with minimal harmonic artifact noise.

  15. Condenser performance test and back-pressure improvement: Final report

    SciTech Connect

    Piskorowski, J.; Beckett, G.; Bell, R.

    1988-04-01

    This document describes condenser performance test and analyses experiences. The testing was performed by Indianapolis Power and Light Company (IPL) on the Petersburg Unit 3 condenser. The initial testing revealed a performance deficiency. Modifications were made to the condenser, air in-leakage was reduced and the vacuum pumps were brought back to their original design capacity. Testing was reperformed after these activities and although a significant performance improvement was achieved deficiencies were still evident. Heat Exchanger Systems, Inc. (HES) was retained as consultants during this testing program. The Central Electricity Generating Board's (CEGB) Central Electricity Research Laboratory (CERL) acting as a subcontractor to HES were retained to perform an analysis of the Petersburg Unit 3 condenser using their EPOC computer code. The results of this analysis are also contained in this document. 3 refs., 48 figs., 3 tabs.

  16. A spectroscopic study of intermediates in the condensation of refractory smokes: Matrix isolation experiments SiO

    NASA Technical Reports Server (NTRS)

    Khanna, R. K.; Stranz, D. D.; Donn, D.

    1980-01-01

    The infrared and Raman spectra of N2 matrix isolated silicon oxides are investigated. The vibrational frequencies of SiO, Si2O2, and Si3O3 were identified and assigned on the basis of normal coordinate analyses. Heating the solid to 50 K (evaporating the matrix) leaves a residue whose infrared spectrum is identical to that of a smoke condensed at ambient temperatures. Further heating of the sample to 500 K leads to significant changes in the band shapes. Investigations of the infrared spectra at several stages of the diffusion process result in the proposal of a mechanism for the transition from molecular properties to those of the residue (bulk) material, which is characterized as Si2O3.

  17. Generation and characterization of aerosols and vapors for inhalation experiments.

    PubMed Central

    Tillery, M I; Wood, G O; Ettinger, H J

    1976-01-01

    Control of aerosol and vapor characteristics that affect the toxicity of inhaled contaminants often determines the methods of generating exposure atmospheres. Generation methods for aerosols and vapors are presented. The characteristics of the resulting exposure atmosphere and the limitations of the various generation methods are discussed. Methods and instruments for measuring the airborne contaminant with respect to various charcteristics are also described. PMID:797565

  18. Condensed Matter Nuclear Science

    NASA Astrophysics Data System (ADS)

    Biberian, Jean-Paul

    2006-02-01

    1. General. A tribute to gene Mallove - the "Genie" reactor / K. Wallace and R. Stringham. An update of LENR for ICCF-11 (short course, 10/31/04) / E. Storms. New physical effects in metal deuterides / P. L. Hagelstein ... [et al.]. Reproducibility, controllability, and optimization of LENR experiments / D. J. Nagel -- 2. Experiments. Electrochemistry. Evidence of electromagnetic radiation from Ni-H systems / S. Focardi ... [et al.]. Superwave reality / I. Dardik. Excess heat in electrolysis experiments at energetics technologies / I. Dardik ... [et al.]. "Excess heat" during electrolysis in platinum/K[symbol]CO[symbol]/nickel light water system / J. Tian ... [et al.]. Innovative procedure for the, in situ, measurement of the resistive thermal coefficient of H(D)/Pd during electrolysis; cross-comparison of new elements detected in the Th-Hg-Pd-D(H) electrolytic cells / F. Celani ... [et al.]. Emergence of a high-temperature superconductivity in hydrogen cycled Pd compounds as an evidence for superstoihiometric H/D sites / A. Lipson ... [et al.]. Plasma electrolysis. Calorimetry of energy-efficient glow discharge - apparatus design and calibration / T. B. Benson and T. O. Passell. Generation of heat and products during plasma electrolysis / T. Mizuno ... [et al.]. Glow discharge. Excess heat production in Pd/D during periodic pulse discharge current in various conditions / A. B. Karabut. Beam experiments. Accelerator experiments and theoretical models for the electron screening effect in metallic environments / A. Huke, K. Czerski, and P. Heide. Evidence for a target-material dependence of the neutron-proton branching ratio in d+d reactions for deuteron energies below 20keV / A. Huke ... [et al.]. Experiments on condensed matter nuclear events in Kobe University / T. Minari ... [et al.]. Electron screening constraints for the cold fusion / K. Czerski, P. Heide, and A. Huke. Cavitation. Low mass 1.6 MHz sonofusion reactor / R. Stringham. Particle detection. Research

  19. Enhancing the Academic Experiences of First-Generation Master's Students

    ERIC Educational Resources Information Center

    Portnoi, Laura M.; Kwong, Tiffany M.

    2011-01-01

    Is being "first generation" significant for undergraduates only? The narratives of 25 first-generation master's students in this phenomenological study suggest not. Participants experienced challenges pursuing their master's degrees, yet these were counterbalanced by other factors. The authors identified five areas that educators may address to…

  20. Lived Experiences of Low Socioeconomic Millennial Generation College Students

    ERIC Educational Resources Information Center

    Thacker, Kelly L.

    2012-01-01

    The characteristics and needs of college students across the United States are ever-changing. As Millennial generation students, born between 1982 and 2003 (Howe & Strauss, 2000), attend college, unique characteristics are present. Commonalities within the Millennial generation have been identified; however, socioeconomic status can impact a…

  1. Gravity Effects in Condensing and Evaporating Films

    NASA Technical Reports Server (NTRS)

    Hermanson, J. C.; Som, S. M.; Allen, J. S.; Pedersen, P. C.

    2004-01-01

    A general overview of gravity effects in condensing and evaporating films is presented. The topics include: 1) Research Overview; 2) NASA Recognizes Critical Need for Condensation & Evaporation Research to Enable Human Exploration of Space; 3) Condensation and Evaporation Research in Reduced Gravity is Enabling for AHST Technology Needs; 4) Differing Role of Surface Tension on Condensing/Evaporating Film Stability; 5) Fluid Mechanisms in Condensing and Evaporating Films in Reduced Gravity; 6) Research Plan; 7) Experimental Configurations for Condensing Films; 8) Laboratory Condensation Test Cell; 9) Aircraft Experiment; 10) Condensation Study Current Test Conditions; 11) Diagnostics; 12) Shadowgraph Images of Condensing n- pentane Film in Unstable (-1g) Configuration; 13) Condensing n-Pentane Film in Normal Gravity (-1g) at Constant Pressure; 14) Condensing n-Pentane Film in Normal Gravity (-1g) with Cyclic Pressure; 15) Non-condensing Pumped Film in Normal Gravity (-1g); 16) Heat Transfer Coefficient in Developing, Unstable Condensing Film in Normal Gravity; 17) Heat Transfer for Unsteady Condensing Film (-1g); 18) Ultrasound Measurement of Film Thickness N-pentane Film, Stable (+1g) Configuration; and 19) Ultrasound Measurement of Film Thickness N-pentane Film, Unstable (-1g) Configuration.

  2. Film condensation in a horizontal rectangular duct

    NASA Technical Reports Server (NTRS)

    Lu, Qing; Suryanarayana, N. V.

    1992-01-01

    Condensation heat transfer in an annular flow regime with and without interfacial waves was experimentally investigated. The study included measurements of heat transfer rate with condensation of vapor flowing inside a horizontal rectangular duct and experiments on the initiation of interfacial waves in condensation, and adiabatic air-liquid flow. An analytical model for the condensation was developed to predict condensate film thickness and heat transfer coefficients. Some conclusions drawn from the study are that the condensate film thickness was very thin (less than 0.6 mm). The average heat transfer coefficient increased with increasing the inlet vapor velocity. The local heat transfer coefficient decreased with the axial distance of the condensing surface, with the largest change at the leading edge of the test section. The interfacial shear stress, which consisted of the momentum shear stress and the adiabatic shear stress, appeared to have a significant effect on the heat transfer coefficients. In the experiment, the condensate flow along the condensing surface experienced a smooth flow, a two-dimensional wavy flow, and a three-dimensional wavy flow. In the condensation experiment, the local wave length decreased with the axial distance of the condensing surface and the average wave length decreased with increasing inlet vapor velocity, while the wave speed increased with increasing vapor velocity. The heat transfer measurements are reliable. And, the ultrasonic technique was effective for measuring the condensate film thickness when the surface was smooth or had waves of small amplitude.

  3. Excitonic condensation in bilayer systems

    NASA Astrophysics Data System (ADS)

    Su, Jung-Jung

    Among the many examples of Bose condensation considered in physics, electron-hole-pair (exciton) condensation has maintained special interest because it has been difficult to realize experimentally, and because of controversy about condensate properties. In this thesis, we studied the various aspects of spontaneous symmetry broken state of exciton in bilayer using mean field theory. We calculated the photoluminescence of excitonic condensation created by laser. We developed a one-dimensional toy model of excitonic supercurrent using mean field theory plus non-equilibrium Green's function (NEGF) which give qualitatively consistent results with experiments. We proposed graphene bilayer as a novel system for excitonic condensation to occur and estimate it to exist even at temperature as high as room temperature.

  4. Field Experiments Aimed To The Analysis of Flood Generation Processes

    NASA Astrophysics Data System (ADS)

    Carriero, D.; Iacobellis, V.; Oliveto, G.; Romano, N.; Telesca, V.; Fiorentino, M.

    The study of the soil moisture dynamics and of the climate-soil-vegetation interac- tion is essential for the comprehension of possible climatic change phenomena, as well as for the analysis of occurrence of extreme hydrological events. In this trend the theoretically-based distribution of floods recently derived by Fiorentino and Ia- cobellis, [ŞNew insights about the climatic and geologic control on the probability distribution of floodsT, Water Resources Research, 2001, 37: 721-730] demonstrated, by an application in some Southern Italy basins, that processes at the hillslope scale strongly influence the basin response by means of the different mechanisms of runoff generation produced by various distributions of partial area contributing. This area is considered as a stochastic variable whose pdf position parameter showed strong de- pendence on the climate as it can seen in the studied basins behavior: in dry zones, where there is the prevalence of the infiltration excess (Horton) mechanism, the basin water loss parameter decreases as basin area increases and the flood peak source area depends on the permeability of soils; in humid zones, with the prevalence of satu- ration excess (Dunne) process, the loss parameter seems independent from the basin area and very sensitive to simple climatic index while only small portion of the area invested by the storm contributes to floods. The purpose of this work is to investigate the consistency of those interpretations by means of field experiments at the hillslope scale to establish a parameterization accounting for soil physical and hydraulic prop- erties, vegetation characteristics and land-use. The research site is the catchment of River Fiumarella di Corleto, which is located in Basilicata Region, Italy, and has a drainage area of approximately 32 km2. The environment has a rather dynamic geo- morphology and very interesting features from the soil-landscape modeling viewpoint [Santini A., A. Coppola, N. Romano, and

  5. Characterization of spacecraft humidity condensate

    NASA Technical Reports Server (NTRS)

    Muckle, Susan; Schultz, John R.; Sauer, Richard L.

    1994-01-01

    When construction of Space Station Freedom reaches the Permanent Manned Capability (PMC) stage, the Water Recovery and Management Subsystem will be fully operational such that (distilled) urine, spent hygiene water, and humidity condensate will be reclaimed to provide water of potable quality. The reclamation technologies currently baselined to process these waste waters include adsorption, ion exchange, catalytic oxidation, and disinfection. To ensure that the baseline technologies will be able to effectively remove those compounds presenting a health risk to the crew, the National Research Council has recommended that additional information be gathered on specific contaminants in waste waters representative of those to be encountered on the Space Station. With the application of new analytical methods and the analysis of waste water samples more representative of the Space Station environment, advances in the identification of the specific contaminants continue to be made. Efforts by the Water and Food Analytical Laboratory at JSC were successful in enlarging the database of contaminants in humidity condensate. These efforts have not only included the chemical characterization of condensate generated during ground-based studies, but most significantly the characterization of cabin and Spacelab condensate generated during Shuttle missions. The analytical results presented in this paper will be used to show how the composition of condensate varies amongst enclosed environments and thus the importance of collecting condensate from an environment close to that of the proposed Space Station. Although advances were made in the characterization of space condensate, complete characterization, particularly of the organics, requires further development of analytical methods.

  6. Evolution and Next Generation of Large Cosmic-Ray Experiments

    NASA Astrophysics Data System (ADS)

    Olinto, Angela

    2016-03-01

    With collaborations involving as many as 32 countries, next generation astro-particle observatories are being built to understand the puzzling origin of the most energetic processes in the Universe. We will review some recent results and the effort behind next generation observatories, which include large arrays of detectors and space missions to study high to ultra-high energy cosmic-rays, neutrinos, and gamma-rays. The great opportunity of word-wide scientific productivity and funding motivates these large-scale efforts, which also face many challenges due to geopolitical events and differences in science funding cultures.

  7. Bose-Einstein Condensation

    SciTech Connect

    El-Sherbini, Th.M.

    2005-03-17

    This article gives a brief review of Bose-Einstein condensation. It is an exotic quantum phenomenon that was observed in dilute atomic gases for the first time in 1995. It exhibits a new state of matter in which a group of atoms behaves as a single particle. Experiments on this form of matter are relevant to many different areas of physics- from atomic clocks and quantum computing to super fluidity, superconductivity and quantum phase transition.

  8. Internally drained condenser for spacecraft thermal management

    NASA Technical Reports Server (NTRS)

    Valenzuela, Javier A.; Drew, Brian C.

    1989-01-01

    This paper presents the results obtained to date in a program to develop a high heat flux condenser for use in two-phase spacecraft thermal management loops. The objective is to obtain a several fold increase in condensation heat transfer coefficient over those which can be achieved with shear-controlled or capillary-wick condensers. The internally drained condenser relies on shaped fins to develop a capillary pressure gradient over the surface of the fins and drive the condensate toward narrow drainage grooves separating the fins. The condensate then flows through a drainage network embedded in the condenser walls. Heat transfer coefficients of up to 8 W/sq cm C were measured in steam, providing a heat transfer enhancement ratio greater than a factor of 8. In the paper the proof-of-concept experiments are described and simplified models to predict the performance of the internally drained condenser are presented.

  9. Few recent experiments on surface studies by second harmonic generation

    SciTech Connect

    Shen, Y.R.

    1985-12-01

    Surface second harmonic generation (SHG) is used to monitor adsorption and desorption of molecules on metal and semiconductor surfaces in ultrahigh vacuum. Surface SHG has also been used to study monolayers of molecules at a liquid/air interface. 13 refs., 6 figs. (WRF)

  10. Bose-Einstein Condensation in Extended Microgravity

    NASA Astrophysics Data System (ADS)

    Scharringhausen, Marco; Quantus Team; Rasel, Ernst Maria

    2012-07-01

    The setup and the envisaged experiment timeline of the QUANTUS-III experiment onboard a sounding rocket to be started in the near future are presented. The major intention of QUANTUS-III is the stable generation of a number of Bose-Einstein condensates as a source for atom interferometry during several minutes of microgravity onboard the sounding rocket. Later missions aim at the realization of atom interferoemeters as precursor satellite missions. These condesates will be generated serially, allowing a large number of repeatable tests. Within such Bose-Einstein condensates, millions of atoms lose their identity and can be described by a single macroscopic wave function. During the expansion over several seconds, the atoms form a giant coherent matter wave that is delocalized on a millimeter scale, which represents a promising source for matter-wave interferometry to test the universality of free fall with quantum matter. Cold quantum gases and, in particular, Bose-Einstein condensates represent a new state of matter which is nowadays established in many laboratories. They offer unique insights into a broad range of fundamental physics as well as prospects for novel quantum sensors. Microgravity will substantially extend the science of quantum gases towards nowadays inaccessible regimes at lowest temperatures, to macroscopic dimensions, and to unequalled durations of unperturbed evolution of these distinguished quantum objects. Right now, the QUANTUS-III experiment is in the development phase, taking heritage from QUANTUS-I and QUANTUS-II. Major components of the engineering model are available. Boundary conditions of the rocket, requirements of the experiment and interface considerations are presented. This include laser stabilization, vacuum technology and magnetic shielding. The planned trajectory of the rocket will have an apogee of 200 - 300 km and a total microgravity time of 4 - 7 minutes, both depending on the total experiment mass.

  11. Colorado's Millennial Generation: Youth Perceptions and Experiences of Nature

    ERIC Educational Resources Information Center

    Barton, Karen S.

    2012-01-01

    This study uses survey and focus group methods to explore attitudes toward and experiences of nature among millennial-aged students in northern Colorado. First, results confirm that young people possess a strong interest in the outdoors yet time, transportation, and new technologies hamper their ability to visit public lands and outdoor spaces.…

  12. NOvA: Building a Next Generation Neutrino Experiment

    SciTech Connect

    Perko, John; Williams, Ron; Miller, Bill

    2013-12-05

    The NOvA neutrino experiment is searching for the answers to some of the most fundamental questions of the universe. This video documents how collaboration between government research institutions like Fermilab, academia and industry can create one of the largest neutrino detectors in the world.

  13. NOvA: Building a Next Generation Neutrino Experiment

    ScienceCinema

    Perko, John; Williams, Ron; Miller, Bill;

    2014-05-30

    The NOvA neutrino experiment is searching for the answers to some of the most fundamental questions of the universe. This video documents how collaboration between government research institutions like Fermilab, academia and industry can create one of the largest neutrino detectors in the world.

  14. Operating experience at the Shamokin Culm burning steam generation plant

    SciTech Connect

    Bender, P.A.; Laukaitis, J.F.; Lockman, H.W.; Samela, D.; Smith, W.G.; Tsoumpas, G.

    1983-06-01

    After 9200 hours of operation it can be concluded that low grade anthracite culm refuse fuel can be properly combusted in a fluidized-bed boiler. The Shamokin Culm Burning Steam Generation Plant has demonstrated environmental compliance while operating over a wide range of operational variables. As changes in equipment and materials are implemented and other fuels are combusted, it is expected that a further demonstration of the Plant's capabilities will be realized.

  15. Automatically generated acceptance test: A software reliability experiment

    NASA Technical Reports Server (NTRS)

    Protzel, Peter W.

    1988-01-01

    This study presents results of a software reliability experiment investigating the feasibility of a new error detection method. The method can be used as an acceptance test and is solely based on empirical data about the behavior of internal states of a program. The experimental design uses the existing environment of a multi-version experiment previously conducted at the NASA Langley Research Center, in which the launch interceptor problem is used as a model. This allows the controlled experimental investigation of versions with well-known single and multiple faults, and the availability of an oracle permits the determination of the error detection performance of the test. Fault interaction phenomena are observed that have an amplifying effect on the number of error occurrences. Preliminary results indicate that all faults examined so far are detected by the acceptance test. This shows promise for further investigations, and for the employment of this test method on other applications.

  16. External priors for the next generation of CMB experiments

    NASA Astrophysics Data System (ADS)

    Manzotti, Alessandro; Dodelson, Scott; Park, Youngsoo

    2016-03-01

    Planned cosmic microwave background (CMB) experiments will improve what we know about neutrino physics, inflation, and dark energy. The low level of noise, together with improved angular resolution, will increase the signal-to-noise ratio of the CMB polarized data as well as the reconstructed lensing potential of large scale structure. Projected constraints on cosmological parameters are tight, but these can be improved even further with information from external experiments. Here, we examine quantitatively the extent to which external priors can lead to improvement in projected constraints from a CMB-Stage IV (S4) experiment on neutrino and dark energy properties. We find that CMB S4 constraints on neutrino mass could be strongly enhanced by external constraints on the cold dark matter density Ωch2 and the Hubble constant H0. If polarization on the largest scales (ℓ<50 ) will not be measured, an external prior on the primordial amplitude As or the optical depth τ will also be important. A CMB constraint on the number of relativistic degrees of freedom, Neff, will benefit from an external prior on the spectral index ns and the baryon energy density Ωbh2. Finally, an external prior on H0 will help constrain the dark energy equation of state (w ).

  17. External priors for the next generation of CMB experiments

    SciTech Connect

    Manzotti, Alessandro; Dodelson, Scott; Park, Youngsoo

    2015-12-08

    Planned cosmic microwave background (CMB) experiments can dramatically improve what we know about neutrino physics, inflation, and dark energy. The low level of noise, together with improved angular resolution, will increase the signal to noise of the CMB polarized signal as well as the reconstructed lensing potential of high redshift large scale structure. Projected constraints on cosmological parameters are extremely tight, but these can be improved even further with information from external experiments. Here, we examine quantitatively the extent to which external priors can lead to improvement in projected constraints from a CMB-Stage IV (S4) experiment on neutrino and dark energy properties. We find that CMB S4 constraints on neutrino mass could be strongly enhanced by external constraints on the cold dark matter density $\\Omega_{c}h^{2}$ and the Hubble constant $H_{0}$. If polarization on the largest scales ($\\ell<50$) will not be measured, an external prior on the primordial amplitude $A_{s}$ or the optical depth $\\tau$ will also be important. A CMB constraint on the number of relativistic degrees of freedom, $N_{\\rm eff}$, will benefit from an external prior on the spectral index $n_{s}$ and the baryon energy density $\\Omega_{b}h^{2}$. Finally, an external prior on $H_{0}$ will help constrain the dark energy equation of state ($w$).

  18. Internal Gravity Waves: Generation and Breaking Mechanisms by Laboratory Experiments

    NASA Astrophysics Data System (ADS)

    la Forgia, Giovanni; Adduce, Claudia; Falcini, Federico

    2016-04-01

    Internal gravity waves (IGWs), occurring within estuaries and the coastal oceans, are manifest as large amplitude undulations of the pycnocline. IGWs propagating horizontally in a two layer stratified fluid are studied. The breaking of an IGW of depression shoaling upon a uniformly sloping boundary is investigated experimentally. Breaking dynamics beneath the shoaling waves causes both mixing and wave-induced near-bottom vortices suspending and redistributing the bed material. Laboratory experiments are conducted in a Perspex tank through the standard lock-release method, following the technique described in Sutherland et al. (2013). Each experiment is analysed and the instantaneous pycnocline position is measured, in order to obtain both geometric and kinematic features of the IGW: amplitude, wavelength and celerity. IGWs main features depend on the geometrical parameters that define the initial experimental setting: the density difference between the layers, the total depth, the layers depth ratio, the aspect ratio, and the displacement between the pycnoclines. Relations between IGWs geometric and kinematic features and the initial setting parameters are analysed. The approach of the IGWs toward a uniform slope is investigated in the present experiments. Depending on wave and slope characteristics, different breaking and mixing processes are observed. Sediments are sprinkled on the slope to visualize boundary layer separation in order to analyze the suspension e redistribution mechanisms due to the wave breaking.

  19. Plant virology and next generation sequencing: experiences with a Potyvirus.

    PubMed

    Kehoe, Monica A; Coutts, Brenda A; Buirchell, Bevan J; Jones, Roger A C

    2014-01-01

    Next generation sequencing is quickly emerging as the go-to tool for plant virologists when sequencing whole virus genomes, and undertaking plant metagenomic studies for new virus discoveries. This study aims to compare the genomic and biological properties of Bean yellow mosaic virus (BYMV) (genus Potyvirus), isolates from Lupinus angustifolius plants with black pod syndrome (BPS), systemic necrosis or non-necrotic symptoms, and from two other plant species. When one Clover yellow vein virus (ClYVV) (genus Potyvirus) and 22 BYMV isolates were sequenced on the Illumina HiSeq2000, one new ClYVV and 23 new BYMV sequences were obtained. When the 23 new BYMV genomes were compared with 17 other BYMV genomes available on Genbank, phylogenetic analysis provided strong support for existence of nine phylogenetic groupings. Biological studies involving seven isolates of BYMV and one of ClYVV gave no symptoms or reactions that could be used to distinguish BYMV isolates from L. angustifolius plants with black pod syndrome from other isolates. Here, we propose that the current system of nomenclature based on biological properties be replaced by numbered groups (I-IX). This is because use of whole genomes revealed that the previous phylogenetic grouping system based on partial sequences of virus genomes and original isolation hosts was unsustainable. This study also demonstrated that, where next generation sequencing is used to obtain complete plant virus genomes, consideration needs to be given to issues regarding sample preparation, adequate levels of coverage across a genome and methods of assembly. It also provided important lessons that will be helpful to other plant virologists using next generation sequencing in the future. PMID:25102175

  20. Plant Virology and Next Generation Sequencing: Experiences with a Potyvirus

    PubMed Central

    Kehoe, Monica A.; Coutts, Brenda A.; Buirchell, Bevan J.; Jones, Roger A. C.

    2014-01-01

    Next generation sequencing is quickly emerging as the go-to tool for plant virologists when sequencing whole virus genomes, and undertaking plant metagenomic studies for new virus discoveries. This study aims to compare the genomic and biological properties of Bean yellow mosaic virus (BYMV) (genus Potyvirus), isolates from Lupinus angustifolius plants with black pod syndrome (BPS), systemic necrosis or non-necrotic symptoms, and from two other plant species. When one Clover yellow vein virus (ClYVV) (genus Potyvirus) and 22 BYMV isolates were sequenced on the Illumina HiSeq2000, one new ClYVV and 23 new BYMV sequences were obtained. When the 23 new BYMV genomes were compared with 17 other BYMV genomes available on Genbank, phylogenetic analysis provided strong support for existence of nine phylogenetic groupings. Biological studies involving seven isolates of BYMV and one of ClYVV gave no symptoms or reactions that could be used to distinguish BYMV isolates from L. angustifolius plants with black pod syndrome from other isolates. Here, we propose that the current system of nomenclature based on biological properties be replaced by numbered groups (I–IX). This is because use of whole genomes revealed that the previous phylogenetic grouping system based on partial sequences of virus genomes and original isolation hosts was unsustainable. This study also demonstrated that, where next generation sequencing is used to obtain complete plant virus genomes, consideration needs to be given to issues regarding sample preparation, adequate levels of coverage across a genome and methods of assembly. It also provided important lessons that will be helpful to other plant virologists using next generation sequencing in the future. PMID:25102175

  1. Control of a Bose-Einstein condensate on a chip by external optical and magnetic potentials

    SciTech Connect

    Maluckov, A.; Petrovic, J.; Gligoric, G.; Hadzievski, Lj.; Lombardi, P.; Schaefer, F.; Cataliotti, F.S.

    2012-09-15

    In this paper we explore the possibilities of control of a Bose-Einstein condensate on an atom chip by the use of potentials generated by photonic and magnetic components. We show that the fields produced by both types of components can be modelled by a generic exponential potential and derive analytic expressions that allow for an easy assessment of their impact on a trapped condensate. Using dynamical numerical simulations we study the transport of the condensate between the control structures on a chip. We study in detail different regimes of the condensate behaviour in an evanescent light potential generated by a photonic structure in the vicinity of the condensate and in magnetic potentials generated by a wire or a coil. The calculations are based on the reported parameters of atom chip setups and available photonic and magnetic components. Finally, the model is verified by an experiment with a condensate on an atom chip and a coil. - Highlights: Black-Right-Pointing-Pointer Generic potential used to describe both the optical evanescent and magnetic fields. Black-Right-Pointing-Pointer An analytic closed form solution found for the impact of a generic potential on a BEC. Black-Right-Pointing-Pointer BEC dynamics calculated for potential time sequences attainable in experiments. Black-Right-Pointing-Pointer Conditions for BEC transfer by an external field identified. Black-Right-Pointing-Pointer Exponential-potential model validated by a BEC-on-chip experiment.

  2. Experiments on sound generation in corrugated pipes with flow.

    PubMed

    Kristiansen, Ulf R; Wiik, Geir A

    2007-03-01

    The article reports acoustic measurements on short corrugated pipes with flow. Such pipes might generate high sound levels associated with length resonances. One of the main objectives of the study was to estimate the location of the effective sources by studying the energy flow through the pipes. It was found that a short section of corrugations will only produce sound effectively when placed at the inflow end, while for fully corrugated pipes, the sound-producing regions are located around the pressure maxima of the observed standing waves. It was further found that the net energy flow is in the upstream direction for nearly the complete length of pipe. PMID:17407869

  3. Dynamic stability experiments in sodium-heated steam generators. [LMFBR

    SciTech Connect

    France, D.M.; Roy, R.; Carlson, R.D.; Chiang, T.

    1984-01-01

    Seventy-two dynamic stability tests were performed in the sodium-heated boiling-water test facility at Argonne National Laboratory. A full-scale LMFBR steam generator tube was employed as the test section operating over the water parameter ranges of 6.9 to 15.9 MPa pressure and 170 to 800 kg/m/sup 2/.s mass flux. The stability thresholds from the test compared well to the predictions of a modified version of a correlation equation recently published by other investigators. Typical experimental data and the modified correlation equation are presented.

  4. Ballistic range experiments on superbooms generated by refraction

    NASA Technical Reports Server (NTRS)

    Sanai, M.; Toong, T.-Y.; Pierce, A. D.

    1976-01-01

    The enhanced sonic boom or supersonic boom generated as a result of atmospheric refraction in threshold Mach number flights was recreated in a ballistic range by firing projectiles at low supersonic speeds into a stratified medium obtained by slowly injecting carbon dioxide into air. The range was equipped with a fast-response dynamic pressure transducer and schlieren photographic equipment, and the sound speed variation with height was controlled by regulating the flow rate of the CO2. The schlieren observations of the resulting flow field indicate that the generated shocks are reflected near the sonic cutoff altitude where local sound speed equals body speed, provided such an altitude exists. Maximum shock strength occurs very nearly at the point where the incident and reflected shocks join, indicating that the presence of the reflected shock may have an appreciable effect on the magnitude of the focus factor. The largest focus factor detected was 1.7 and leads to an estimate that the constant in the Guiraud-Thery scaling law should have a value of 1.30.

  5. Model Experiment on the Generation of the Korotkoff Sounds

    NASA Astrophysics Data System (ADS)

    Arakawa, Mieko

    1980-07-01

    The mechanism of the genesis of the Korotkoff sounds is investigated by model experiment using latex tubes and a segment of isolated blood vessel of dogs. The tube compliance is much reduced when the transmural (internal minus external) pressure is very high or very low, and increases radically for intermediate states. It can be concluded that there are two different mechanisms by which the sounds are emitted. One is durable sounds caused by self-excited vibration in the process of collapse of the tube, and the other is impulsive sounds emitted transiently when the tube compliance is abruptly decreased. It is possible to explain qualitatively the change of sound phases over a wide range from systole to diastole as an appropriate mixture of durable and impulsive sounds.

  6. Preliminary experiments on surface flow visualization in the cryogenic wind tunnel by use of condensing or freezing gases

    NASA Technical Reports Server (NTRS)

    Goodyer, M. J.

    1988-01-01

    Cryogenic wind tunnel users must have available surface flow visualization techniques to satisfy a variety of needs. While the ideal from an aerodynamic stand would be non-intrusive, until an economical technique is developed there will be occasions when the user will be prepared to resort to an intrusive method. One such method is proposed, followed by preliminary evaluation experiments carried out in environments representative of the cryogenic nitrogen tunnel. The technique uses substances which are gases at normal temperature and pressure but liquid or solid at cryogenic temperatures. These are deposited on the model in localized regions, the patterns of the deposits and their subsequent melting or evaporation revealing details of the surface flow. The gases were chosen because of the likelihood that they will not permanently contaminate the model or tunnel. Twenty-four gases were identified as possibly suitable and four of these were tested from which it was concluded that surface flow direction can be shown by the method. Other flow details might also be detectable. The cryogenic wind tunnel used was insulated on the outside and did not show signs of contamination.

  7. Technology for the Next-Generation-Mobile User Experience

    NASA Astrophysics Data System (ADS)

    Delagi, Greg

    The current mobile-handset market is a vital and growing one, being driven by technology advances, including increased bandwidth and processing performance, as well as reduced power consumption and improved screen technologies. The 3G/4G handsets of today are multimedia internet devices with increased screen size, HD video and gaming, interactive touch screens, HD camera and camcorders, as well as incredible social, entertainment, and productivity applications. While mobile-technology advancements to date have made us more social in many ways, new advancements over the next decade will bring us to the next level, allowing mobile users to experience new types of "virtual" social interactions with all the senses. The mobile handsets of the future will be smart autonomous-lifestyle devices with a multitude of incorporated sensors, applications and display options, all designed to make your life easier and more productive! With future display media, including 3D imaging, virtual interaction and conferencing will be possible, making every call feel like you are in the same room, providing an experience far beyond today's video conferencing technology. 3D touch-screen with integrated image-projection technologies will work in conjunction with gesturing to bring a new era of intuitive mobile device applications, interaction, and information sharing. Looking to the future, there are many challenges to be faced in delivering a smart mobile companion device that will meet the user demands. One demand will be for the availability of new and compelling services, and features on the "mobile companion". These mobile companions will be more than just Internet devices, and will function as on-the-go workstations, allowing users to function as if they were sitting in front of their computer in the office or at home. The massive amounts of data that will be transmitted through, to and from these mobile companions will require immense improvements in system performance, including

  8. Infrasound Generated by Strombolian Eruptions - Insights from Laboratory Experiments

    NASA Astrophysics Data System (ADS)

    Dabrowa, A.; Phillips, J. C.; Rust, A.; Green, D. N.

    2010-12-01

    In recent years infrasonic monitoring at volcanoes has become an increasingly common tool. Much of the current work on interpreting volcano infrasound has concentrated on Strombolian eruptions, and several mechanisms have been suggested for the sound produced at these eruptions. However, the precise mechanisms at the vent need to be identified and understood if infrasound recorded in the field is to be used to infer conditions in the volcanic system. In this work, laboratory experiments using audio recordings coupled with high speed video footage have been conducted to gain a deeper understanding of these sounds. A simplified analogue model is used as an analogy for a Strombolian eruption: an air bubble rises through a tank containing a viscous Newtonian liquid (golden syrup) and bursts at the surface. Although the experimental set-up is simple and idealized, it allows control of physical properties and measurement of the processes observed far more accurately than would be possible in the field. Physical parameters which may control the form of the acoustic wave produced, such as liquid viscosity (achieved by dilution of pure golden syrup with water) and bubble volume are investigated. Initial results show that the onset of the main part of the acoustic waveform occurs concurrently with the onset of bubble rupture. Trends in the amplitude and frequency of the acoustic waveform, as well as bubble rupture speed are seen as the liquid viscosity varied. A number of candidate mechanisms for the production of sound during the experiments have been investigated, and synthetic waveforms compared to experimental data. These include the flow of gas through a growing hole from a pressurised reservoir (the bubble), and the mass flux due to the collapse of the bubble film. Importantly it has been shown that even in this very simple case - the sound produced by the bursting of a hemispherical bubble formed at the surface of a viscous liquid - is not as simple as some theories

  9. Cylindrical Liner Z-pinch Experiments on the MAGPIE Generator

    NASA Astrophysics Data System (ADS)

    Burdiak, Guy; Lebedev, Sergey V.; Harvey-Thompson, Adam J.; Swadling, George F.; Suzuki-Vidal, Francisco; Skidmore, Jonathan; Suttle, Lee; Khoory, Essa; Pickworth, Louisa; de Grouchy, Philip; Hall, Gareth N.; Bland, Simon N.; Weinwurm, Marcus; Chittenden, Jeremy P.

    2012-10-01

    Experimental data from gas-filled cylindrical liner z-pinch experiments is presented. The MAGPIE current (1.4 MA, 240 ns) is applied to a thin walled (80um) Al tube with a static gas-fill inside. The system is diagnosed axially using interferometry, optical streak photography and optical spectroscopy. We observe a series of cylindrically converging shock waves driven into the gas-fill from the inside liner surface. No bulk motion of the liner occurs. The timing of the shocks and their trajectories provide information on the shock launching mechanisms. This in turn allows a study of the response of the liner to the current pulse. Shock wave timing is compared to measurements of the liner resistance and optical images of the liner's outside surface. The system provides a useful, essentially 1D problem for testing MagLIF relevant MHD codes, particularly with regards to EOS, strength and resistivity models. This work may also be relevant to the study of shocks in astrophysical plasmas. The shocks launched into the gas radiatiate strongly; spatially resolved optical spectroscopy data and radial electron density profiles from interferometry images provide evidence for a radiative precursor ahead of the first shock. Instabilities are seen to develop in the downstream regions.

  10. Chondrules of the Very First Generation in Bencubbin/CH-like Meteorites QUE94411 and Hammadah Al Hamra 237: Condensation Origin at High Ambient Nebular Temperatures

    NASA Technical Reports Server (NTRS)

    Krot, Alexander N.; Meibom, Anders; Russell, Sara S.; Young, Edward; Alexander, Conel M.; McKeegan, Kevin D.; Lofgren, Gary; Cuzzi, Jeff; Zipfel, Jutta; Keil, Klaus

    2000-01-01

    Chondrules in QUE94411 and HH 237 formed at high ambient T prior to condensation of Fe,Ni-metal following a large scale thermal event that resulted in complete vaporization of a solar nebula region. These chondrules escaped subsequent remelting.

  11. A NOVEL HIGH-SPEED METHOD FOR THE GENERATION OF 4-ARYLDIHYDROPYRIMIDINE COMPOUND LIBRARIES USING A MICROWAVE-ASSISTED BIGINELLI CONDENSATION PROTOCOL -

    EPA Science Inventory

    In this presentation we report the application of microwave assisted chemistry to the parallel synthesis of 4-aryl-3,4-dihydropyrimidin-2(1H)-ones employing a solventless Biginelli multicomponent condensation protocol. The novel method employs neat mixtures of B-ketoesters, aryl ...

  12. Condensation model for the ESBWR passive condensers

    SciTech Connect

    Revankar, S. T.; Zhou, W.; Wolf, B.; Oh, S.

    2012-07-01

    In the General Electric's Economic simplified boiling water reactor (GE-ESBWR) the passive containment cooling system (PCCS) plays a major role in containment pressure control in case of an loss of coolant accident. The PCCS condenser must be able to remove sufficient energy from the reactor containment to prevent containment from exceeding its design pressure following a design basis accident. There are three PCCS condensation modes depending on the containment pressurization due to coolant discharge; complete condensation, cyclic venting and flow through mode. The present work reviews the models and presents model predictive capability along with comparison with existing data from separate effects test. The condensation models in thermal hydraulics code RELAP5 are also assessed to examine its application to various flow modes of condensation. The default model in the code predicts complete condensation well, and basically is Nusselt solution. The UCB model predicts through flow well. None of condensation model in RELAP5 predict complete condensation, cyclic venting, and through flow condensation consistently. New condensation correlations are given that accurately predict all three modes of PCCS condensation. (authors)

  13. Confinement Contains Condensates

    SciTech Connect

    Brodsky, Stanley J.; Roberts, Craig D.; Shrock, Robert; Tandy, Peter C.

    2012-03-12

    Dynamical chiral symmetry breaking and its connection to the generation of hadron masses has historically been viewed as a vacuum phenomenon. We argue that confinement makes such a position untenable. If quark-hadron duality is a reality in QCD, then condensates, those quantities that have commonly been viewed as constant empirical mass-scales that fill all spacetime, are instead wholly contained within hadrons; i.e., they are a property of hadrons themselves and expressed, e.g., in their Bethe-Salpeter or light-front wave functions. We explain that this paradigm is consistent with empirical evidence, and incidentally expose misconceptions in a recent Comment.

  14. Condensed Matter Nuclear Science

    NASA Astrophysics Data System (ADS)

    Takahashi, Akito; Ota, Ken-Ichiro; Iwamura, Yashuhiro

    Preface -- 1. General. Progress in condensed matter nuclear science / A. Takahashi. Summary of ICCF-12 / X. Z. Li. Overview of light water/hydrogen-based low-energy nuclear reactions / G. H. Miley and P. J. Shrestha -- 2. Excess heat and He detection. Development of "DS-reactor" as the practical reactor of "cold fusion" based on the "DS-cell" with "DS-cathode" / Y. Arata and Y.-C. Zhang. Progress in excess of power experiments with electrochemical loading of deuterium in palladium / V. Violante ... [et al.]. Anomalous energy generation during conventional electrolysis / T. Mizuno and Y. Toriyabe. "Excess heat" induced by deuterium flux in palladium film / B. Liu ... [et al.]. Abnormal excess heat observed during Mizuno-type experiments / J.-F. Fauvarque, P. P. Clauzon and G. J.-M. Lallevé. Seebeck envelope calorimetry with a Pd|D[symbol]O + H[symbol]SO[symbol] electrolytic cell / W.-S. Zhang, J. Dash and Q. Wang. Observation and investigation of nuclear fusion and self-induced electric discharges in liquids / A. I. Koldamasov ... [et al.]. Description of a sensitive seebeck calorimeter used for cold fusion studies / E. Storms. Some recent results at ENEA / M. Apicella ... [et al.]. Heat measurement during plasma electrolysis / K. Iizumi ... [et al.]. Effect of an additive on thermal output during electrolysis of heavy water with a palladium cathode / Q. Wang and J. Dash. Thermal analysis of calorimetric systems / L. D'Aulerio ... [et al.]. Surface plasmons and low-energy nuclear reactions triggering / E. Castagna ... [et al.]. Production method for violent TCB jet plasma from cavity / F. Amini. New results and an ongoing excess heat controversy / L. Kowalski ... [et al.] -- 3. Transmutation. Observation of surface distribution of products by X-ray fluorescence spectrometry during D[symbol] gas permeation through Pd Complexes / Y. Iwamura ... [et al.]. Discharge experiment using Pd/CaO/Pd multi-layered cathode / S. Narita ... [et al.]. Producing transmutation

  15. In-Space technology experiments program. A high efficiency thermal interface (using condensation heat transfer) between a 2-phase fluid loop and heatpipe radiator: Experiment definition phase

    NASA Astrophysics Data System (ADS)

    Pohner, John A.; Dempsey, Brian P.; Herold, Leroy M.

    1990-07-01

    Space Station elements and advanced military spacecraft will require rejection of tens of kilowatts of waste heat. Large space radiators and two-phase heat transport loops will be required. To minimize radiator size and weight, it is critical to minimize the temperature drop between the heat source and sink. Under an Air Force contract, a unique, high-performance heat exchanger is developed for coupling the radiator to the transport loop. Since fluid flow through the heat exchanger is driven by capillary forces which are easily dominated by gravity forces in ground testing, it is necessary to perform microgravity thermal testing to verify the design. This contract consists of an experiment definition phase leading to a preliminary design and cost estimate for a shuttle-based flight experiment of this heat exchanger design. This program will utilize modified hardware from a ground test program for the heat exchanger.

  16. In-Space technology experiments program. A high efficiency thermal interface (using condensation heat transfer) between a 2-phase fluid loop and heatpipe radiator: Experiment definition phase

    NASA Technical Reports Server (NTRS)

    Pohner, John A.; Dempsey, Brian P.; Herold, Leroy M.

    1990-01-01

    Space Station elements and advanced military spacecraft will require rejection of tens of kilowatts of waste heat. Large space radiators and two-phase heat transport loops will be required. To minimize radiator size and weight, it is critical to minimize the temperature drop between the heat source and sink. Under an Air Force contract, a unique, high-performance heat exchanger is developed for coupling the radiator to the transport loop. Since fluid flow through the heat exchanger is driven by capillary forces which are easily dominated by gravity forces in ground testing, it is necessary to perform microgravity thermal testing to verify the design. This contract consists of an experiment definition phase leading to a preliminary design and cost estimate for a shuttle-based flight experiment of this heat exchanger design. This program will utilize modified hardware from a ground test program for the heat exchanger.

  17. Condensed Plasmas under Microgravity

    NASA Technical Reports Server (NTRS)

    Morfill, G. E.; Thomas, H. M.; Konopka, U.; Rothermel, H.; Zuzic, M.; Ivlev, A.; Goree, J.; Rogers, Rick (Technical Monitor)

    1999-01-01

    Experiments under microgravity conditions were carried out to study 'condensed' (liquid and crystalline) states of a colloidal plasma (ions, electrons, and charged microspheres). Systems with approximately 10(exp 6) microspheres were produced. The observed systems represent new forms of matter--quasineutral, self-organized plasmas--the properties of which are largely unexplored. In contrast to laboratory measurements, the systems under microgravity are clearly three dimensional (as expected); they exhibit stable vortex flows, sometimes adjacent to crystalline regions, and a central 'void,' free of microspheres.

  18. Operational experience on the MP-200 series commercial wind turbine generators

    NASA Technical Reports Server (NTRS)

    Rose, M. B.

    1982-01-01

    The MP-200 wind turbine generator is described. The mechanical system, microprocessor controller, and display devices, are described. Also discussed are modifications to the prototype, operational experience, and MP-600 systems development.

  19. Condensed Matter Nuclear Science

    NASA Astrophysics Data System (ADS)

    Takahashi, Akito; Ota, Ken-Ichiro; Iwamura, Yashuhiro

    Preface -- 1. General. Progress in condensed matter nuclear science / A. Takahashi. Summary of ICCF-12 / X. Z. Li. Overview of light water/hydrogen-based low-energy nuclear reactions / G. H. Miley and P. J. Shrestha -- 2. Excess heat and He detection. Development of "DS-reactor" as the practical reactor of "cold fusion" based on the "DS-cell" with "DS-cathode" / Y. Arata and Y.-C. Zhang. Progress in excess of power experiments with electrochemical loading of deuterium in palladium / V. Violante ... [et al.]. Anomalous energy generation during conventional electrolysis / T. Mizuno and Y. Toriyabe. "Excess heat" induced by deuterium flux in palladium film / B. Liu ... [et al.]. Abnormal excess heat observed during Mizuno-type experiments / J.-F. Fauvarque, P. P. Clauzon and G. J.-M. Lallevé. Seebeck envelope calorimetry with a Pd|D[symbol]O + H[symbol]SO[symbol] electrolytic cell / W.-S. Zhang, J. Dash and Q. Wang. Observation and investigation of nuclear fusion and self-induced electric discharges in liquids / A. I. Koldamasov ... [et al.]. Description of a sensitive seebeck calorimeter used for cold fusion studies / E. Storms. Some recent results at ENEA / M. Apicella ... [et al.]. Heat measurement during plasma electrolysis / K. Iizumi ... [et al.]. Effect of an additive on thermal output during electrolysis of heavy water with a palladium cathode / Q. Wang and J. Dash. Thermal analysis of calorimetric systems / L. D'Aulerio ... [et al.]. Surface plasmons and low-energy nuclear reactions triggering / E. Castagna ... [et al.]. Production method for violent TCB jet plasma from cavity / F. Amini. New results and an ongoing excess heat controversy / L. Kowalski ... [et al.] -- 3. Transmutation. Observation of surface distribution of products by X-ray fluorescence spectrometry during D[symbol] gas permeation through Pd Complexes / Y. Iwamura ... [et al.]. Discharge experiment using Pd/CaO/Pd multi-layered cathode / S. Narita ... [et al.]. Producing transmutation

  20. Generations.

    PubMed

    Chambers, David W

    2005-01-01

    Groups naturally promote their strengths and prefer values and rules that give them an identity and an advantage. This shows up as generational tensions across cohorts who share common experiences, including common elders. Dramatic cultural events in America since 1925 can help create an understanding of the differing value structures of the Silents, the Boomers, Gen Xers, and the Millennials. Differences in how these generations see motivation and values, fundamental reality, relations with others, and work are presented, as are some applications of these differences to the dental profession. PMID:16623137

  1. Principal component analysis of soft x-ray signals generated by the PF-1000 facility in experiments with solid targets

    NASA Astrophysics Data System (ADS)

    Kowalska-Strzęciwilk, Ewa; Skrzeczanowski, Wojciech; Czarnecka, Agata; Kubkowska, Monika; Paduch, Marian; Zielińska, Ewa

    2014-05-01

    The paper presents the analysis of soft x-ray signals generated in the PF-1000 facility equipped with a modified inner electrode with a central tungsten insert of 50 mm diameter in experiments with tungsten and carbon samples. The PF-1000 machine was operated with pure deuterium filling under the initial pressure of 1.3 hPa. The machine was powered using a condenser bank charged initially to 24 kV, corresponding to the stored energy of 380 kJ, with the maximum discharge current amounted to 1.8 MA. For investigation of plasma stream-sample interactions, we applied 16-frame laser interferometry, optical spectroscopy and soft x-ray measurements with the use of a system of four silicon pin-diodes. In this paper, we mainly focus on the principal component analysis (PCA) of the registered x-ray signals to find a corelation between the neutron yield and observed maxima in signals. X-ray signals collected by four pin-diodes covered a 9 cm range in front of the electrode ends. Each diode collected a signal from the circle of 3 cm diameter. The presented PCA analysis is based on 57 PF discharges and 16 parameters are taken into account in the analysis. The study of signals from the pin-diode system showed good correlation between the neutron yield and the maximum in the x-ray signal, which appeared about 1000-1300 ns after the maximum of plasma compression.

  2. Expressions of Generativity through Family Leisure: Experiences of Grandparents and Adult Grandchildren

    ERIC Educational Resources Information Center

    Hebblethwaite, Shannon; Norris, Joan

    2011-01-01

    The purpose of this study was to understand the expression of generativity among grandparents and their adult grandchildren through their experiences of family leisure. Fourteen dyads of grandparents and adult grandchildren were interviewed about their experience of family leisure. The findings illustrate the important role that family leisure…

  3. Using Phenomenology to Understand Experiences of Racism for Second-Generation South Asian Women

    ERIC Educational Resources Information Center

    Beharry, Pauline; Crozier, Sharon

    2008-01-01

    The purpose of this investigation was to describe the lived experiences of racism for second-generation Canadian women of South Asian descent and how this affected their identity. Six adult co-researchers shared their experiences of what occurred when faced with racism. A phenomenological approach was employed, out of which five categories…

  4. Little Experience with ICT: Are They Really the Net Generation Student-Teachers?

    ERIC Educational Resources Information Center

    So, Hyo-Jeong; Choi, Hyungshin; Lim, Wei Ying; Xiong, Yao

    2012-01-01

    The aim of this study is to investigate the complexity of past experiences with ICT, pedagogical beliefs, and attitude toward ICT in education that the Net Generation student teachers have about their intention to teach and learn with technology. This study has a particular focus on their lived experiences as school students where ICT related…

  5. Connection and Commitment: Exploring the Generation and Experience of Emotion in a Participatory Drama

    ERIC Educational Resources Information Center

    Dunn, Julie; Bundy, Penny; Stinson, Madonna

    2015-01-01

    Emotion is a complex and important aspect of participatory drama experience. This is because drama work of this kind provokes emotional responses to both actual and dramatic worlds. This paper identifies two key features of participatory drama that influence the generation and experience of emotion: commitment and connection. These features are…

  6. Participatory Reality Constitution: A Phenomenological Study of Generative Experiences in Higher Education Classrooms

    ERIC Educational Resources Information Center

    Saiter, Sean M. Avila

    2012-01-01

    This phenomenological inquiry into the felt experience of participatory sense-making and collaborative presence in small groups explores where and when a common field of resonance is generated among individuals. The experience is named "participatory reality constitution" (PRC). Nine co-participants who met criteria of having experienced…

  7. The Role of Physical Education and Other Formative Experiences of Three Generations of Female Football Fans

    ERIC Educational Resources Information Center

    Pope, Stacey; Kirk, David

    2014-01-01

    The experiences of female sports fans have been largely marginalised in academic research to date and little research has examined the formative sporting experiences of female spectators. This article draws on 51 semi-structured interviews with three generations of female fans of one (men's) professional football club (Leicester City), to…

  8. Optimizing process vacuum condensers

    SciTech Connect

    Lines, J.R.; Tice, D.W.

    1997-09-01

    Vacuum condensers play a critical role in supporting vacuum processing operations. Although they may appear similar to atmospheric units, vacuum condensers have their own special designs, considerations and installation needs. By adding vacuum condensers, precondensers and intercondensers, system cost efficiency can be optimized. Vacuum-condensing systems permit reclamation of high-value product by use of a precondenser, or reduce operating costs with intercondensers. A precondenser placed between the vacuum vessel and ejector system will recover valuable process vapors and reduce vapor load to an ejector system--minimizing the system`s capital and operating costs. Similarly, an intercondenser positioned between ejector stages can condense motive steam and process vapors and reduce vapor load to downstream ejectors as well as lower capital and operating costs. The paper describes vacuum condenser systems, types of vacuum condensers, shellside condensing, tubeside condensing, noncondensable gases, precondenser pressure drop, system interdependency, equipment installation, and equipment layout.

  9. Vapor condensation on a turbulent liquid interface

    NASA Technical Reports Server (NTRS)

    Helmick, M. R.; Khoo, B. C.; Sonin, A. A.

    1987-01-01

    An experimental investigation which seeks the fundamental relationship between the interfacial condensation rate and the parameters which control it when the liquid side is turbulent is discussed. The scaling laws for free-surface condensation are discussed for this case. It is argued that the condensation of cryogenic liquids can, in principle, be simulated in experiments using steam and water. Data are presented for the condensation rate in terms of the dimensionless scaling parameters which involve the fluid properties and the liquid-side turbulence velocity and length scales.

  10. Simulation of Homogeneous Condensation of Ethanol in High Pressure Supersonic Nozzle Flows using BGK Condensation Model

    NASA Astrophysics Data System (ADS)

    Kumar, Rakesh; Levin, D. A.

    2011-05-01

    In the present work, we have simulated the homogeneous condensation flow of ethanol using the Bhatnagar-Gross-Krook (BGK) based condensation model for the experimental conditions of Wegener et al. [1]. In an earlier work carried out by Gallagher-Rogers et al. [2], it was found not possible to simulate the experimental conditions using the direct simulation Monte-Carlo (DSMC) based condensation model. In this work we use a statistical-BGK approach to model condensation and compare our simulated predictions of the point of condensation onset and the distribution of mass fraction along the nozzle centerline with experiments. The experiments provide data for different cases corresponding to varying amounts of ethanol concentration, compared to air, for total mixture pressures which remains mostly constant for all cases. Our numerical results show good agreement with the experiments, thus validating our BGK based condensation model for high pressure flow applications.

  11. STATegra EMS: an Experiment Management System for complex next-generation omics experiments

    PubMed Central

    2014-01-01

    High-throughput sequencing assays are now routinely used to study different aspects of genome organization. As decreasing costs and widespread availability of sequencing enable more laboratories to use sequencing assays in their research projects, the number of samples and replicates in these experiments can quickly grow to several dozens of samples and thus require standardized annotation, storage and management of preprocessing steps. As a part of the STATegra project, we have developed an Experiment Management System (EMS) for high throughput omics data that supports different types of sequencing-based assays such as RNA-seq, ChIP-seq, Methyl-seq, etc, as well as proteomics and metabolomics data. The STATegra EMS provides metadata annotation of experimental design, samples and processing pipelines, as well as storage of different types of data files, from raw data to ready-to-use measurements. The system has been developed to provide research laboratories with a freely-available, integrated system that offers a simple and effective way for experiment annotation and tracking of analysis procedures. PMID:25033091

  12. Aging of nuclear station diesel generators: Evaluation of operating and expert experience: Workshop

    SciTech Connect

    Hoopingarner, K.R.; Vause, J.W.

    1987-08-01

    Pacific Northwest Laboratory (PNL) evaluated operational and expert experience pertaining to the aging degradation of diesel generators in nuclear service. The research, sponsored by the US Nuclear Regulatory Commission (NRC), identified and characterized the contribution of aging to emergency diesel generator failures. This report, Volume II, reports the results of an industry-wide workshop held on May 28 and 29, 1986, to discuss the technical issues associated with aging of nuclear service emergency diesel generators. The technical issues discussed most extensively were: man/machine interfaces, component interfaces, thermal gradients of startup and cooldown and the need for an accurate industry database for trend analysis of the diesel generator system.

  13. Research and Development Supporting a Next Generation Germanium Double Beta Decay Experiment

    NASA Astrophysics Data System (ADS)

    Rielage, Keith; Elliott, Steve; Chu, Pinghan; Goett, Johnny; Massarczyk, Ralph; Xu, Wenqin

    2015-10-01

    To improve the search for neutrinoless double beta decay, the next-generation experiments will increase in source mass and continue to reduce backgrounds in the region of interest. A promising technology for the next generation experiment is large arrays of Germanium p-type point contact detectors enriched in 76-Ge. The experience, expertise and lessons learned from the MAJORANA DEMONSTRATOR and GERDA experiments naturally lead to a number of research and development activities that will be useful in guiding a future experiment utilizing Germanium. We will discuss some R&D activities including a hybrid cryostat design, background reduction in cabling, connectors and electronics, and modifications to reduce assembly time. We acknowledge the support of the U.S. Department of Energy through the LANL/LDRD Program.

  14. Report on the NASA Soft and Complex Condensed Matter Workshop

    NASA Technical Reports Server (NTRS)

    Singh, Bhim (Technical Monitor); Chaikin, Paul; Nagel, Sidney

    2003-01-01

    During the past decade, NASA has been a leading U.S. supporter of soft and complex condensed matter research. Experiments in space shuttles, MIR, the International Space Station (ISS), as well as ground-based research have provided new insights into several areas including hard sphere colloids, crystal growth, phase ordering, and transport of complex fluids at the critical point. To help define the next generation of flight experiments needed to answer remaining important questions in the field of soft and complex condensed matter, NASA's Office of Biological and Physical Science sponsored a workshop on Soft and Complex Condensed Matter, March 6, 2003. This workshop asked leading members in the field of Soft and Complex Condensed Matter (at the APS March Meeting) to help identify exciting unanswered questions in the field, along with specific research topics for which the absence of gravity would enable significant results unobtainable by other means. The workshop was attended by 24 participants from universities across the U.S. and from five different countries (in addition to NASA GRC participants).

  15. Condensation in Titan's lower atmosphere

    NASA Astrophysics Data System (ADS)

    Lavvas, P.; Griffith, C. A.; Yelle, R. V.

    2011-10-01

    We present a self-consistent description of Titan's aerosols-clouds-gases system and compare our results with the optical properties retrieved from measurements made by the Descent Imager / Spectral Radiometer (DISR) experiment on the Huygens probe [4]. Our calculations include the condensation of methane, ethane and hydrogen cyanide on photochemical aerosols produced in the thermosphere. Our results suggest that the two distinct extinction layers observed by DISR below 80 km are produced by HCN and methane condensation, respectively, while for the Huygens' equatorial conditions simulated here, the contribution of ethane clouds to the total opacity is negligible

  16. Condensates in Jovian Atmospheres

    NASA Technical Reports Server (NTRS)

    West, R.

    1999-01-01

    Thermochemical equilibrium theory which starts with temperature/pressure profiles, compositional information and thermodynamic data for condensable species in the jovian planet atmospheres predicts layers of condensate clouds in the upper troposphere.

  17. Dual-monitor deterministic hardware for visual stimuli generation in neuroscience experiments.

    PubMed

    Gazziro, Mario; Almeida, Lirio

    2010-01-01

    This article describes the development of a dual-monitor visual stimulus generator that is used in neuroscience experiments with invertebrates such as flies. The experiment consists in the visualization of two fixed images that are displaced horizontally according to the stimulus data. The system was developed using off-the-shelf FPGA kits and it is capable of displaying 640x480 pixels with 256 intensity levels at 200 frames per second (FPS) on each monitor. A Raster plot of the experiment with the superimposed stimuli was generated as the result of this work. A novel architecture was developed, using the same DOT Clock for both monitors, and its implementation generates a perfect synchronism in both devices. PMID:21096378

  18. Aging of nuclear station diesel generators: Evaluation of operating and expert experience: Phase 1, Study

    SciTech Connect

    Hoopingarner, K.R.; Vause, J.W.; Dingee, D.A.; Nesbitt, J.F.

    1987-08-01

    Pacific Northwest Laboratory evaluated operational and expert experience pertaining to the aging degradation of diesel generators in nuclear service. The research, sponsored by the US Nuclear Regulatory Commission (NRC), identified and characterized the contribution of aging to emergency diesel generator failures. This report, Volume I, reviews diesel-generator experience to identify the systems and components most subject to aging degradation and isolates the major causes of failure that may affect future operational readiness. Evaluations show that as plants age, the percent of aging-related failures increases and failure modes change. A compilation is presented of recommended corrective actions for the failures identified. This study also includes a review of current, relevant industry programs, research, and standards. Volume II reports the results of an industry-wide workshop held on May 28 and 29, 1986 to discuss the technical issues associated with aging of nuclear service emergency diesel generators.

  19. Film condensation in a horizontal rectangular duct

    NASA Technical Reports Server (NTRS)

    Lu, Qing; Suryanarayana, N. V.

    1993-01-01

    Condensation heat transfer in a horizontal rectangular duct was experimentally and analytically investigated. To prevent the dripping of condensate on the film, the experiment was conducted inside a horizontal rectangular duct with vapor condensing only on the bottom cooled plate of the duct. R-113 and FC-72 (Fluorinert Electronic Fluid developed by the 3M Company) were used as the condensing fluids. The experimental program included measurements of film thickness, local and average heat transfer coefficients, wave length, wave speed, and a study of wave initiation. The measured film thickness was used to obtain the local heat transfer coefficient. The wave initiation was studied both with condensation and with an adiabatic air-liquid flow. The test sections used in both experiments were identical.

  20. The Second Generation Hypernuclear Spectroscopy at JLab Hall C (E01-011 experiment)

    SciTech Connect

    Matsumura, Akihiko

    2008-11-01

    The second generation Λ hypernuclear spectroscopy by (e,e’K{sup +}) reaction has been carried out successfully at JLab in 2005. New configurations, HKS and Tilt method, significantly improved both energy resolution and statistics. Systematic error depend on tuning procedure was estimated by the blind analysis. Analysis is in the final stage. Third generation experiment (JLab E05-115) will be performed in the summer of 2009 w/ new e’ spectrometer (HES).

  1. Self-generated Magnetic Fields in Blast-wave Driven Rayleigh-Taylor Experiments

    NASA Astrophysics Data System (ADS)

    Flaig, Markus; Plewa, Tomasz

    2014-10-01

    We study the generation of magnetic fields via the Biermann battery effect in blast-wave driven Rayleigh-Taylor experiments. Previous estimates have shown that in a typical experiment, one should expect fields in the MG range to be generated, with the potential to influence the Rayleigh-Taylor morphology. We perform two- and three-dimensional numerical simulations, where we solve the extended set of MHD equations known as the Braginskii equations. The simulation parameters reflect the physical conditions in past experiments performed on the OMEGA laser and potential future experiments on the NIF laser facility. When neglecting the friction force between electrons and ions in the simulations, magnetic fields of the order of a few 0.1 MG (with a plasma smaller than 1000) are generated, and are found to be dynamically significant. However, it turns out that once the friction force is included, the magnetic fields become much smaller (with a plasma beta greater than 100000) which have negligible influence on the dynamics of the system. Our results therefore indicate that, contrary to previous speculations, it is highly unlikely that self-generated magnetic fields can influence the morphology of a typical blast-wave driven Rayleigh-Taylor experiment. M.F. and T.P. were supported by the DOE Grant DE-FG52- 09NA29548 and the NSF Grant AST-1109113. This research used resources of the National Energy Re.

  2. Collisions of Dark Solitons in Elongated Bose-Einstein Condensates

    SciTech Connect

    Stellmer, S.; Becker, C.; Soltan-Panahi, P.; Richter, E.-M.; Doerscher, S.; Baumert, M.; Kronjaeger, J.; Sengstock, K.; Bongs, K.

    2008-09-19

    We present experimental data showing the head-on collision of dark solitons generated in an elongated Bose-Einstein condensate. No discernable interaction can be recorded, in full agreement with the fundamental theoretical concepts of solitons as mutually transparent quasiparticles. Our soliton generation technique allows for the creation of solitons with different depths; hence, they can be distinguished and their trajectories be followed. Simulations of the 1D-Gross-Pitaevskii equation have been performed to compare the experiment with a mean-field description.

  3. A Phenomenological Investigation of the Lived Experiences of Successful First Generation Hispanic College Students

    ERIC Educational Resources Information Center

    Puente, Christina C.

    2013-01-01

    This qualitative phenomenological research study investigated the lived experiences of five successful first generation Hispanic college students. Participants' interviews were analyzed using Creswell's (2007) six steps for analyzing phenomenological studies. Findings from this study affirm the factors for student success in college regarding…

  4. 13_2_30: Experiences, Perceptions and Expectations of Retail Employment for Generation Y

    ERIC Educational Resources Information Center

    Broadbridge, Adelina M.; Maxwell, Gillian A.; Ogden, Susan M.

    2007-01-01

    Purpose: The purpose of this paper is to examine Generation Y, potential graduate entrants to UK retailing, in respect of their job experiences, career perceptions and initial employment expectations. Design/methodology/approach: Utilising qualitative research methods, an exploratory study was undertaken with 33 students (all of whom fell into the…

  5. Four Generations of Women's Educational Experience in a Rural Chinese Community

    ERIC Educational Resources Information Center

    Huang, Haigen; Placier, Peggy

    2015-01-01

    Our study sought to understand changes in gender inequality in education across four generations of rural Chinese women's educational experiences in a small community in southern China. The 24 interviews and numerous informal conversations with 12 women showed that gender-based favouritism for men and against women undergirded family expectations,…

  6. An Exploration of First-Generation College Students' Career Development Beliefs and Experiences

    ERIC Educational Resources Information Center

    Tate, Kevin A.; Caperton, William; Kaiser, Dakota; Pruitt, Nathan T.; White, Heather; Hall, Eric

    2015-01-01

    First-generation college students (FGCS) represent a large proportion of individuals seeking higher education in the United States; yet this population does not perform as well academically as, and persist to graduation at lower rates than, their peers who have more familial context for the college-going experience. Completing a college degree is…

  7. Preliminary design of condenser cleansing schedule

    SciTech Connect

    Warberg, J.; Foraker, E.K.; Civera, A.G.; Daley, M.L.

    1995-04-01

    Analysis of the operations of a fossil power plant for a 5-year period revealed a year-round trend of operating inefficiently due to elevated condenser back pressure, particularly during the summer months. A further 5-month longitudinal study between May and September of an individual condenser unit revealed a positive correlation between increasing inlet-circulating water temperature and above-design condenser back pressure. Moreover, condenser cleansing resulted in a return to approximately the design operating condition. A physical analysis of increased heat-rate and lost power generation from inefficient condenser back pressure was accomplished. Based on these observations and economic analysis, a preliminary cleansing schedule for periods of increasing circulating water temperature was derived. Further studies are planned to validate the proposed cleansing schedule.

  8. Simulation of Experiments Generating Collisionless Shocks With Intense Lasers Using the CRASH Code

    NASA Astrophysics Data System (ADS)

    Grosskopf, M. J.; Drake, R. P.; Kuranz, C. C.; Rutter, E. M.; Park, H. S.; Kugland, N. L.; Pollaine, S.; Ross, J. S.; Remington, B. A.; Ryutov, D.; Spitkovsky, A.; Gargate, L.; Gregori, G.; Bell, A.; Murphy, C.; Sakawa, Y.; Kuramitsu, Y.; Takabe, H.; Froula, D. H.; Fiksel, G.; Miniati, F.; Koenig, M.; Ravasio, A.; Liang, E.; Woosley, N.

    2011-10-01

    Collisionless shocks, shocks generated by plasma wave interactions in regions where the collisional mean-free-path for particles is long compared to the length scale for shock interaction, are found ubiquitously in astrophysics. Experiments to investigate collisionless shocks in a laboratory-scale system are being carried out on intense lasers; measuring the density, temperature, magnetic field, and velocity of counter-streaming flows generated by laser ablation. This poster reports hydrodynamic simulations modeling the ablative flow of plasma generated in order to assess potential designs and infer properties of collected data from previous single foil experiments. This work is funded by the Predictive Sciences Academic Alliances Program in NNSA-ASC via grant DEFC52-08NA28616.

  9. Investigation of Electric and Self-Generated Magnetic Fields in Implosion Experiments on OMEGA

    NASA Astrophysics Data System (ADS)

    Igumenshchev, I. V.; Nilson, P. M.; Goncharov, V. N.; Li, C. K.; Zylstra, A. B.; Petrasso, R. D.

    2013-10-01

    Electric and self-generated magnetic fields in direct-drive implosion experiments on the OMEGA laser were investigated using proton radiography. The experiments use plastic-shell targets with various surface defects (glue spot, wire, and stalk mount) to seed perturbations and generate localized electromagnetic fields at the ablation surface and in the plasma corona surrounding the targets. Proton radiographs show features from these perturbations and quasi-spherical multiple shell structures around the capsules at earlier times of implosions (up to ~700 ps for a 1-ns laser pulse) indicating the development of the fields. Two-dimensional magnetohydrodynamic simulations of these experiments predict the growth of magnetic fields up to several MG. The simulated distributions of electromagnetic fields were used to produce proton images, which show good agreement with experimental radiographs. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  10. Generation of Artificial Acoustic-Gravity Waves and Traveling Ionospheric Disturbances in HF Heating Experiments

    NASA Astrophysics Data System (ADS)

    Pradipta, R.; Lee, M. C.; Cohen, J. A.; Watkins, B. J.

    2015-10-01

    We report the results of our ionospheric HF heating experiments to generate artificial acoustic-gravity waves (AGW) and traveling ionospheric disturbances (TID), which were conducted at the High-frequency Active Auroral Research Program facility in Gakona, Alaska. Based on the data from UHF radar, GPS total electron content, and ionosonde measurements, we found that artificial AGW/TID can be generated in ionospheric modification experiments by sinusoidally modulating the power envelope of the transmitted O-mode HF heater waves. In this case, the modulation frequency needs to be set below the characteristic Brunt-Vaisala frequency at the relevant altitudes. We avoided potential contamination from naturally-occurring AGW/TID of auroral origin by conducting the experiments during geomagnetically quiet time period. We determine that these artificial AGW/TID propagate away from the edge of the heated region with a horizontal speed of approximately 160 m/s.

  11. Bose-Einstein Condensate-Hidden Riches for New Forms of Technology and Energy Generation; Potential for Glimpse into Inner Reality

    NASA Astrophysics Data System (ADS)

    Reed, Don

    With the announcement of the recent successful production of a Bose-Einstein condensate (BEC) of photons, a circle has been completed which started in 1925 with the vision of Albert Einstein and Satyendra Nath Bose - a sustained macroscopic condensed state of matter where all atoms are in the same lowest quantum state. The creation of an all-optical BEC, involving a surprisingly straightforward "tabletop" method which bypasses the normally requisite laser/evaporative cooling equipment and ultra-high vacuum chambers necessary for production of the standard delicate atomic BEC, elevates this phenomenon to a new level well beyond its current perception as mere laboratory curiosity. Accordingly, this development certainly heralds eventual incorporation of atomic and photon BECs as standard operating components of energy-efficient mechanical, optical and electrical systems, implying novel ingenious engineering protocols amenable to all the tools of non-linear and quantum optics. Pointing towards such a promising technological future are the suggestion that a photon BEC could serve as a new high-energy ultra-violet (UV) laser photon source, as well as the recent unprecedented implementation of a closed-loop atom circuit (toroidal atomic BEC) demonstrating precise control of superfluid current flow, forecasting the coveted development of an atomic SQUID. Perhaps more significantly, the new highly robust and manageable optical BEC will allow heretofore unfathomable precise probing of the atomic and nano-levels of nature, affording novel high-quality testing procedures of the major foundations of quantum mechanics itself. Such a primary advancement, providing a clearer glimpse into the microscopic realms, may present us as never before with an unprecedented view of the quantum engine that underpins physical reality itself and help place the contextual nature of entanglement and quantum superposition on a firmer foundation. Thus, further progress in achieving mastery over

  12. Evaluation of stack criteria pollutant gas absorption in the new generation thermoelectric water condenser fitted with laminar impinger type heat exchangers

    SciTech Connect

    Baldwin, T.

    1995-12-31

    Title IV of the Clean Air Act Amendments of 1990 authorized the Environmental Protection Agency to establish an Acid Rain Program to reduce the adverse effects of acidic deposition. The Act specifically stipulated that CEMS (continuous emissions monitoring systems) be used to measure the stack emissions under this program. Along with these rules, comes the task of the Stack Tester (Reference Method) to routinely perform RATA (Relative Accuracy Test Audit) tests on the installed CEMS. This paper presents a laboratory and field test sequence to evaluate the signal attenuation through the gas sample conditioning, water condensation removal process, using laminar flow impinger heat exchangers. This method is compared to the EPA CFR 40, Part 60, Appendix A, Method 6, glass impinger train, commonly used by RATA stack testers. CFR 40, Part 75 revisions as of the CAAA 1990, requires more stringent certification and CEMS performance standards. These standards are summarized and related to gas absorption in both the thermoelectric cooler heat exchanger and the Method 6 glass impinger train system. As an incentive to reduce the frequency of RATA tests required per year, emitters are encouraged to achieve relative accuracies of 7.5% or less compared to the reference method. This incentive requires better reference method test apparatus definition. This paper will explore these alternatives and provide test data for comparison to the currently available apparatus. Also discussed is the theory of Electronic Gas Sample Coolers and their practical application to the removal of water from stack gas.

  13. Condensation of the air-steam mixture in a vertical tube condenser

    NASA Astrophysics Data System (ADS)

    Havlík, Jan; Dlouhý, Tomáš

    2016-03-01

    This paper deals with the condensation of water vapour in the presence of non-condensable air. Experimental and theoretical solutions of this problem are presented here. A heat exchanger for the condensation of industrial waste steam containing infiltrated air was designed. The condenser consists of a bundle of vertical tubes in which the steam condenses as it flows downwards with cooling water flowing outside the tubes in the opposite direction. Experiments with pure steam and with mixtures of steam with added air were carried out to find the dependence of the condensation heat transfer coefficient (HTC) on the air concentration in the steam mixture. The experimental results were compared with the theoretical formulas describing the cases. The theoretical determination of the HTC is based on the Nusselt model of steam condensation on a vertical wall, where the analogy of heat and mass transfer is used to take into account the behaviour of air in a steam mixture during the condensation process. The resulting dependencies obtained from the experiments and obtained from the theoretical model have similar results. The significant decrease in the condensation HTC, which begins at very low air concentrations in a steam mixture, was confirmed.

  14. The Next Generation Ground-based CMB experiment, CMB-S4

    NASA Astrophysics Data System (ADS)

    Carlstrom, John E.; CMB-S4 Collaboration

    2016-06-01

    This talk will review the goals and status of the community planning for the next generation ground-based CMB experiment, CMB-S4. Following the detection of CMB polarization in 2002, the current generation of ground-based experiments each fielding of order 1000 superconducting detectors (Stage II experiments) have led to the first detection of the much fainter lensing B-mode polarization signal and the most stringent constraints on the level of the B-mode signal from inflationary gravitational waves. We can expect significant advances in the next few years as the ongoing ground-based experiments deploy of order 10,000 detectors (Stage III). The CMB community is now planning an ambitious next generation (Stage IV) ground-based program with order of 500,000 detectors, CMB-S4, to achieve critical threshold crossing goals of 1) detecting or ruling out large field inflationary models, 2) determining the effective number and masses of the neutrinos, and 3) providing precision constraints on dark energy through its impact on structure formation.

  15. Generation of surface waves by an underwater moving bottom: experiments and application to tsunami modeling

    NASA Astrophysics Data System (ADS)

    Gordillo, Leonardo; Jamin, Timothée; Ruiz-Chavarría, Gerardo; Berhanu, Michael; Falcon, Eric

    2013-11-01

    Most of the ocean waves that we observe in nature are generated by processes that take place near the ocean surface. This occurs mainly because fluid layers reduce significantly the transfer of motion between the source and the free surface as the depth increases. In any case, when the disturbances at a deep source are wide and fast enough, a wave can still be generated. The archetype of this kind of process is tsunami generation: during earthquakes, the seabed of the ocean experiences a sudden net vertical displacement that can yield waves capable of flooding entire coastlines. In this talk, we will focus on laboratory experiments concerning the generation of free surface waves in a three-dimensional uniform layer whose bottom uplifts suddenly. Based on simultaneous measurements of the free surface deformation and the velocity field, we analyze the wave generation dependence on the bottom kinematics. Our results display excellent agreement with a classical linear theory of gravity waves. In addition, we develop a new theoretical approach that can be applied to improve real-time numerical simulations used by the tsunami hazard mitigation programs. Supported by the AXA Research Fund.

  16. Radiation-Hydrodynamic Simulation of Experiments With Intense Lasers Generating Collisionless Interpenetrating Plasmas

    NASA Astrophysics Data System (ADS)

    Grosskopf, Michael; Drake, R.; Kuranz, C.; Park, H.; Kugland, N.; Pollaine, S.; Ross, J.; Remington, B.; Spitkovsky, A.; Gargate, L.; Gregori, G.; Bell, A.; Murphy, C.; Meinecke, J.; Reville, B.; Sakawa, Y.; Kuramitsu, Y.; Takabe, H.; Froula, D.; Fiksel, G.; Miniati, F.; Koenig, M.; Ravasio, A.; Liang, E.; Woolsey, N.

    2012-05-01

    Collisionless shocks, shocks generated by plasma wave interactions in regions where the collisional mean-free-path for ions is long compared to the length scale for instabilities that generate magnetic fields, are found in many astrophysical systems such as supernova remnants and planetary bow shocks. Generating conditions to investigate collisionless shock physics is difficult to achieve in a laboratory setting; however, high-energy-density physics facilities have made this a possibility. Experiments whose goal is to investigate the production and growth of magnetic fields in collisionless shocks in laboratory-scale systems are being carried out on intense lasers, several of which are measuring the plasma properties and magnetic field strength in counter-streaming, collisionless flows generated by laser ablation. This poster reports radiation-hydrodynamic simulations using the CRASH code to model the ablative flow of plasma generated in order to assess potential designs, as well as infer properties of collected data from previous experiments. This work is funded by the Predictive Sciences Academic Alliances Program in NNSA-ASC via grant DEFC52- 08NA28616, by the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant number DE-FG52-09NA29548, and by the National Laser User Facility Program, grant number DE-NA0000850.

  17. A qualitative study of adaptation experiences of 1.5-generation Asian Americans.

    PubMed

    Kim, Bryan S K; Brenner, Bradley R; Liang, Christopher T H; Asay, Penelope A

    2003-05-01

    Adaptation experiences of 1.5-generation Asian American college students (N = 10) were examined using the consensual qualitative research method. Results indicated 4 domains of adaptation experiences: preimmigration experiences, acculturation and enculturation experiences, intercultural relationships, and support systems. Participants reported that English proficiency played a significant role in their initial adjustment. Currently, most of the participants reported feeling identified with both the U.S. and Asian cultures. Some participants reported having experienced racism in the past. Many participants noted that they currently have no difficulty establishing friendships with culturally different persons. Participants reported currently feeling most close to friends of a similar background and that they usually seek support from friends, family, and religious organizations, but not from a psychologist or counselor. PMID:12760327

  18. Operating experience with California's first coal fired enhanced oil recovery steam generator

    SciTech Connect

    Waldman, G.B.

    1983-11-01

    This article discusses the experiences of operating Pyropower Corporation's ''Pyroflow'' circulating fluidized bed steam generation plant in Bakersfield, California. The Pyroflow plant is shown to be demonstrating its ability to provide a reliable source of steam for enhanced oil recovery. Actual operating problems have been minimal, and those which have occurred have involved plant auxilliary equipment rather than the steam generator itself. Fluidized bed combustion is the only practical means of burning coal in environmentally sensitive areas such as California without the use of flue gas scrubbing for sulfur dioxide control. This plant operates on the circulating bed concept as distinct from conventional fluidized beds which have a fixed bed depth.

  19. Time-of-arrival analysis applied to ELF/VLF wave generation experiments at HAARP

    NASA Astrophysics Data System (ADS)

    Moore, R. C.; Fujimaru, S.

    2012-12-01

    Time-of-arrival (TOA) analysis is applied to observations performed during ELF/VLF wave generation experiments at the High-frequency Active Auroral Research Program (HAARP) HF transmitter in Gakona, Alaska. In 2012, a variety of ELF/VLF wave generation techniques were employed to identify the dominant source altitude for each case. Observations were performed for beat-wave modulation, AM modulation, STF modulation, ICD modulation, and cubic frequency modulation, among others. For each of these cases, we identify the dominant ELF/VLF source altitude and compare the experimental results with theoretical HF heating predictions.

  20. Characterisation of heat transfer and pressure drop in condensation processes within mini-channel tubes with last generation of refrigerant fluids

    NASA Astrophysics Data System (ADS)

    Lopez Belchi, D. Alejandro

    Heat exchanger developments are driven by energetic efficiency increase and emissionreduction. To reach the standards new system are required based on mini-channels. Mini-channels can be described as tubes with one or more ports extruded in aluminiumwith hydraulic diameter are in the range of 0.2 to 3 mm. Its use in refrigeration systemsfor some years ago is a reality thanks to the human ability to made micro-scale systems.Some heat exchanger enterprises have some models developed specially for their use inautomotive sector, cooling sector, and industrial refrigeration without having a deepknowledge of how these reduced geometries affect the most important parameters suchas pressure drop and the heat transfer coefficient. To respond to this objective, an exhaustive literature review of the last two decades hasbeen performed to determinate the state of the research. Between all the publications,several models have been selected to check the predicting capacities of them becausemost of them were developed for single port mini-channel tubes. Experimentalmeasurements of heat transfer coefficient and frictional pressure drop were recorded inan experimental installation built on purpose at the Technical University of Cartagena.Multiple variables are recorded in this installation in order to calculate local heattransfer coefficient in two-phase condensing flow within mini-channels. Both pressure drop and heat transfer coefficient experimental measurements arecompared to the previously mentioned models. Most of them capture the trend correctlybut others fail predicting experimental data. These differences can be explained by theexperimental parameters considered during the models development. In some cases themodels found in the literature were developed specific conditions, consequently theirpredicting capacities are restricted. As main contributions, this thesis provides new modelling tools for mini-channelscondensing pressure drop and heat transfer coefficient

  1. FLASH hydrodynamic simulations of experiments to explore the generation of cosmological magnetic fields

    NASA Astrophysics Data System (ADS)

    Scopatz, A.; Fatenejad, M.; Flocke, N.; Gregori, G.; Koenig, M.; Lamb, D. Q.; Lee, D.; Meinecke, J.; Ravasio, A.; Tzeferacos, P.; Weide, K.; Yurchak, R.

    2013-03-01

    We report the results of FLASH hydrodynamic simulations of the experiments conducted by the University of Oxford High Energy Density Laboratory Astrophysics group and its collaborators at the Laboratoire pour l'Utilisation de Lasers Intenses (LULI). In these experiments, a long-pulse laser illuminates a target in a chamber filled with Argon gas, producing shock waves that generate magnetic fields via the Biermann battery mechanism. The simulations show that the result of the laser illuminating the target is a series of complex hydrodynamic phenomena.

  2. Outdoor Science Experiment Classes; Raising the Next Generation for Researchers and Teachers of Natural Sciences

    NASA Astrophysics Data System (ADS)

    Shida, Masakazu; Danjo, Shinji; Takahashi, Noriaki

    The objectives of the outdoor science experiment classes are; for a few tens of young students and pupils as trainees to develop large-scale natural science experiments and to demonstrate them for the approximately 3,000 visitors in the venue of the EXPO park at Osaka. This method, though hardly realisable in the framework of school education, is proposed with recent successful examples, as a new means of active learning for the motivated next generation who wishes to enter the field of natural science as researchers and/or teachers.

  3. Condensate polishers add operating reliability and flexibility

    SciTech Connect

    Layman, C.M.; Bennett, L.L.

    2008-08-15

    Many of today's advanced steam generators favour either an all-volatile treatment or oxygenated treatment chemistry programme, both of which require strict maintenance of an ultra-pure boiler fedwater ro condensate system. Those requirements are many times at odds with the lower-quality water sources, such as greywater, available for plant makeup and cooling water. Adding a condensate polisher can be a simple, cost-effective solution. 4 figs.

  4. Anti-Reflective Coatings R&D for Next Generation Neutrinoless Double Beta Experiments

    NASA Astrophysics Data System (ADS)

    Leder, Alexander; Cuore Collaboration

    2016-03-01

    The Cyogenic Underground Observatory for Rare Events (CUORE) is a ton-scale cryogenic source=detector experiment designed to search for the Neutrinoless Double Beta Decay (0 νββ) of 130Te. CUORE currently utilizes a single phonon readout channel per crystal; adding a second channel for scintillation or Cherenkov light would improve particle identification for actively rejecting background events. This light would be collected via semiconductor wafers covered with anti-reflective coatings. These coatings maximize light absorption. In this talk, I will discuss the coating optimization regarding material and structure, and its implications for designing the next generation CUORE-style experiment. In addition, I will discuss projections for possible sensitivities of next generation 0 νββ searches that use dual channel light-phonon readouts.

  5. Operating experience with the 200 kW MOD-OA wind turbine generators

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.; Saunders, A. L.; Nyland, T. W.; Shaltens, R. K.

    1981-01-01

    The machine configuration and its advantages and disadvantages, particularly as it affects reliability are discussed. The machine performance, both availability and power output characteristics are described. The Mod-OA operational experience is documented. The characteristics of the wind energy generated, the machine performance, and the subsystem strengths and weaknesses are discussed. An assessment of the project success in fulfilling its goals and objectives is also presented.

  6. Generation and reduction of the data for the Ulysses gravitational wave experiment

    NASA Technical Reports Server (NTRS)

    Agresti, R.; Bonifazi, P.; Iess, L.; Trager, G. B.

    1987-01-01

    A procedure for the generation and reduction of the radiometric data known as REGRES is described. The software is implemented on a HP-1000F computer and was tested on REGRES data relative to the Voyager I spacecraft. The REGRES data are a current output of NASA's Orbit Determination Program. The software package was developed in view of the data analysis of the gravitational wave experiment planned for the European spacecraft Ulysses.

  7. A Proof-Of-Principle Echo-Enabled Harmonic Generation Experiment at SLAC

    SciTech Connect

    Dunning, Michael; Colby, Eric; Ding, Yuantao; Frederico, Joel; Gilevich, Sasha; Hast, Carsten; Jobe, R.; McCormick, Douglas; Nelson, Janice; Raubenheimer, Tor; Soong, Ken; Stupakov, Gennady; Szalata, Zenon; Walz, Dieter; Weathersby, Stephen; Woodley, Mark; Xiang, Dao; Corlett, John; Penn, Gregory; Prestemon, Soren; Qiang, Ji; /LBL, Berkeley /LBL, Berkeley /LBL, Berkeley /LBL, Berkeley /LPHE, Lausanne

    2011-05-20

    In this paper we describe the technical design of an ongoing proof-of-principle echo-enabled harmonic generation (EEHG) experiment at the Next Linear Collider Test Accelerator (NLCTA) at SLAC.We present the design considerations and the technical details of the experiment. Recently a new method, entitled echo-enabled harmonic generation, was proposed for generation of high harmonics using the beam echo effect. In an EEHG free electron laser (FEL), an electron beam is energy modulated in a modulator and then sent through a dispersive section with a high dispersion strength. After this first stage, the modulation obtained in the modulator is macroscopically washed out, while simultaneously introducing complicated fine structure (separated energy bands) into the phase space of the beam. A second laser is used to further modulate the beam energy in a second modulator. After passing through a second dispersive section, the separated energy bands will be converted into current modulation and the echo signal then occurs as a recoherence effect caused by the mixing of the correlations between the modulation in the second modulator and the fine structures in the beam. The EEHG scheme has a remarkable up-frequency conversion efficiency; it has been shown that the EEHG FEL scheme may allow generation of soft x-rays directly from a UV seed laser in a single stage. In order to confirm the physics behind the EEHG technique and benchmark the theory, a proof-of-principleEEHG experimentwas planned at SLAC. The experiment is now in a commissioning stage and the preliminary results are reported in a separate paper of these proceedings. In this paper we present the design considerations and the details of the experiment setup.

  8. Next Generation Endstation for Concurrent Measurements of Charged Products and Photons in LCLS FEL Experiments

    NASA Astrophysics Data System (ADS)

    Osipov, T.; Rolles, D.; Bostedt, C.; Castagna, J.-C.; Hartmann, R.; Bozek, J. D.; Schlichting, I.; Strüder, L.; Ullrich, J.; Berrah, N.

    2012-11-01

    We are designing and building the next generation multi-purpose instrumentation especially adapted to accommodate unique large-area, single-photon counting pnCCD detectors together with advanced many-particle ion and electron imaging spectrometers (reaction microscope, REMI; velocity map imaging, VMI; magnetic bottle) for simultaneous detection of scattered and fluorescent photons and charged particles in experiments at the LCLS FEL.

  9. Orbital diamagnetic susceptibility in excitonic condensation phase

    NASA Astrophysics Data System (ADS)

    Sugimoto, Koudai; Ohta, Yukinori

    2016-08-01

    We study the orbital diamagnetic susceptibility in excitonic condensation phase using the mean-field approximation for a two-band model defined on a square lattice. We find that, in semiconductors, the excitonic condensation acquires a finite diamagnetic susceptibility due to spontaneous hybridization between the valence and the conduction bands, whereas in semimetals, the diamagnetic susceptibility in the normal phase is suppressed by the excitonic condensation. We also study the orbital diamagnetic and Pauli paramagnetic susceptibilities of Ta2NiSe5 using a two-dimensional three-band model and find that the calculated temperature dependence of the magnetic susceptibility is in qualitative agreement with experiment.

  10. The generation and amplification of intergalactic magnetic fields in analogue laboratory experiments with high power lasers

    NASA Astrophysics Data System (ADS)

    Gregori, G.; Reville, B.; Miniati, F.

    2015-11-01

    The advent of high-power laser facilities has, in the past two decades, opened a new field of research where astrophysical environments can be scaled down to laboratory dimensions, while preserving the essential physics. This is due to the invariance of the equations of magneto-hydrodynamics to a class of similarity transformations. Here we review the relevant scaling relations and their application in laboratory astrophysics experiments with a focus on the generation and amplification of magnetic fields in cosmic environment. The standard model for the origin of magnetic fields is a multi stage process whereby a vanishing magnetic seed is first generated by a rotational electric field and is then amplified by turbulent dynamo action to the characteristic values observed in astronomical bodies. We thus discuss the relevant seed generation mechanisms in cosmic environment including resistive mechanism, collision-less and fluid instabilities, as well as novel laboratory experiments using high power laser systems aimed at investigating the amplification of magnetic energy by magneto-hydrodynamic (MHD) turbulence. Future directions, including efforts to model in the laboratory the process of diffusive shock acceleration are also discussed, with an emphasis on the potential of laboratory experiments to further our understanding of plasma physics on cosmic scales.

  11. Self-generated magnetic fields in direct-drive implosion experiments

    NASA Astrophysics Data System (ADS)

    Igumenshchev, I. V.; Zylstra, A. B.; Li, C. K.; Nilson, P. M.; Goncharov, V. N.; Petrasso, R. D.

    2014-06-01

    Electric and self-generated magnetic fields in direct-drive implosion experiments on the OMEGA Laser Facility were investigated employing radiography with ˜10- to 60-MeV protons. The experiment used plastic-shell targets with imposed surface defects (glue spots, wires, and mount stalks), which enhance self-generated fields. The fields were measured during the 1-ns laser drive with an on-target intensity ˜1015 W/cm2. Proton radiographs show multiple ring-like structures produced by electric fields ˜107 V/cm and fine structures from surface defects, indicating self-generated fields up to ˜3 MG. These electric and magnetic fields show good agreement with two-dimensional magnetohydrodynamic simulations when the latter include the ∇Te × ∇ne source, Nernst convection, and anisotropic resistivity. The simulations predict that self-generated fields affect heat fluxes in the conduction zone and, through this, affect the growth of local perturbations.

  12. Diagnostics of deuterium gas-puff z-pinch experiments on the GIT-12 generator

    NASA Astrophysics Data System (ADS)

    Cikhardt, J.; Klir, D.; Rezac, K.; Kubes, P.; Kravarik, J.; Batobolotova, B.; Sila, O.; Turek, K.; Shishlov, A.; Labetsky, A.; Kokshenev, V.; Chedizov, R.; Ratakhin, N.; Varlachev, V.; Garapatsky, A.; Dudkin, G.; Padalko, V.; GIT-12 Team

    2014-10-01

    Z-pinch experiments with a deuterium gas-puff and an outer plasma shell generated by plasma guns were carried out on the GIT-12 generator at the IHCE in Tomsk. Using this novel configuration of the load, the neutron yields from the DD reaction were significantly increased from 2×1011 up to 3×1012 neutrons per shot at the current level of about 3 MA. In addition to recent experiments, the threshold activation detectors were used in order to get the information about the energy spectrum of the generated neutrons. The copper, indium, and lead samples were irradiated by the pulse of the neutrons generated during the experimental shot. The decay radiation of the products from the reactions 63Cu(n,2n)62Cu, 115In(n, γ) 116 mIn and 206Pb (n,3n)204mPb was observed using gamma spectrometer. According to the used neutron ToF scintillation detectors, the energy of neutrons reaches up to 20 MeV. The work was supported by the MSMT of the Czech Republic research Programs No. ME090871, No. LG13029, by the GACR Grant No. P205/12/0454, Grant CRA IAEA No. 17088 and RFBR research Project No. 13-08-00479-a.

  13. Self-generated magnetic fields in direct-drive implosion experiments

    SciTech Connect

    Igumenshchev, I. V.; Nilson, P. M.; Goncharov, V. N.; Zylstra, A. B.; Li, C. K.; Petrasso, R. D.

    2014-06-15

    Electric and self-generated magnetic fields in direct-drive implosion experiments on the OMEGA Laser Facility were investigated employing radiography with ∼10- to 60-MeV protons. The experiment used plastic-shell targets with imposed surface defects (glue spots, wires, and mount stalks), which enhance self-generated fields. The fields were measured during the 1-ns laser drive with an on-target intensity ∼10{sup 15} W/cm{sup 2}. Proton radiographs show multiple ring-like structures produced by electric fields ∼10{sup 7} V/cm and fine structures from surface defects, indicating self-generated fields up to ∼3 MG. These electric and magnetic fields show good agreement with two-dimensional magnetohydrodynamic simulations when the latter include the ∇T{sub e} × ∇n{sub e} source, Nernst convection, and anisotropic resistivity. The simulations predict that self-generated fields affect heat fluxes in the conduction zone and, through this, affect the growth of local perturbations.

  14. Self-generated magnetic fields in direct-drive implosion experiments

    SciTech Connect

    Igumenshchev, I. V.; Zylstra, A. B.; Li, C. K.; Nilson, P. M.; Goncharov, V. N.; Petrasso, R. D.

    2014-06-13

    Electric and self-generated magnetic fields in direct-drive implosion experiments on the OMEGA Laser Facility were investigated employing radiography with ~10- to 60-MeV protons. The experiment used plastic-shell targets with imposed surface defects (glue spots, wires, and mount stalks), which enhance self-generated fields. The fields were measured during the 1-ns laser drive with an on-target intensity ~1015 W/cm2. Proton radiographs show multiple ring-like structures produced by electric fields ~107 V/cm and fine structures from surface defects, indicating self-generated fields up to ~3 MG. These electric and magnetic fields show good agreement with two-dimensional magnetohydrodynamic simulations when the latter include the ∇Te × ∇ne source, Nernst convection, and anisotropic resistivity. The simulations predict that self-generated fields affect heat fluxes in the conduction zone and, through this, affect the growth of local perturbations.

  15. Megagauss field generation for high-energy-density plasma science experiments.

    SciTech Connect

    Rovang, Dean Curtis; Struve, Kenneth William; Porter, John Larry Jr.

    2008-10-01

    There is a need to generate magnetic fields both above and below 1 megagauss (100 T) with compact generators for laser-plasma experiments in the Beamlet and Petawatt test chambers for focused research on fundamental properties of high energy density magnetic plasmas. Some of the important topics that could be addressed with such a capability are magnetic field diffusion, particle confinement, plasma instabilities, spectroscopic diagnostic development, material properties, flux compression, and alternate confinement schemes, all of which could directly support experiments on Z. This report summarizes a two-month study to develop preliminary designs of magnetic field generators for three design regimes. These are, (1) a design for a relatively low-field (10 to 50 T), compact generator for modest volumes (1 to 10 cm3), (2) a high-field (50 to 200 T) design for smaller volumes (10 to 100 mm3), and (3) an extreme field (greater than 600 T) design that uses flux compression. These designs rely on existing Sandia pulsed-power expertise and equipment, and address issues of magnetic field scaling with capacitor bank design and field inductance, vacuum interface, and trade-offs between inductance and coil designs.

  16. FLASH MHD simulations of experiments that study shock-generated magnetic fields

    NASA Astrophysics Data System (ADS)

    Tzeferacos, P.; Fatenejad, M.; Flocke, N.; Graziani, C.; Gregori, G.; Lamb, D. Q.; Lee, D.; Meinecke, J.; Scopatz, A.; Weide, K.

    2015-12-01

    We summarize recent additions and improvements to the high energy density physics capabilities in FLASH, highlighting new non-ideal magneto-hydrodynamic (MHD) capabilities. We then describe 3D Cartesian and 2D cylindrical FLASH MHD simulations that have helped to design and analyze experiments conducted at the Vulcan laser facility. In these experiments, a laser illuminates a carbon rod target placed in a gas-filled chamber. A magnetic field diagnostic (called a Bdot) employing three very small induction coils is used to measure all three components of the magnetic field at a chosen point in space. The simulations have revealed that many fascinating physical processes occur in the experiments. These include megagauss magnetic fields generated by the interaction of the laser with the target via the Biermann battery mechanism, which are advected outward by the vaporized target material but decrease in strength due to expansion and resistivity; magnetic fields generated by an outward expanding shock via the Biermann battery mechanism; and a breakout shock that overtakes the first wave, the contact discontinuity between the target material and the gas, and then the initial expanding shock. Finally, we discuss the validation and predictive science we have done for this experiment with FLASH.

  17. Al wire array implosion experiments on the inductive storage generator GIT-4

    SciTech Connect

    Baksht, R.B.; Datsko, I.M.; Kim, A.A.; Loginov, S.V.; Labetsky, A.Yu.; Shishlov, A.V.

    1995-12-31

    In High Current Electronics Institute the first successful wire array implosion experiments on the inductive storage generator GIT-4 with a long conductive plasma opening switch were carried out in 1989. Those experiments were aimed at obtaining the radiation with quantum energy below 1 keV. Recently the authors carried out aluminum wire array implosion experiments on the GIT-4 generator varying the value of mr{sub 0}{sup 2} parameter from 2.2 {center_dot} 10{sup {minus}5} to 2.4 {center_dot} 10{sup {minus}4} g {center_dot} cm at different charge voltage and at different values of downstream inductance. The aims were two-fold: (1) to obtain the {eta}-dependence of the K-shell radiation yield and determine the liner parameters which provide a maximum K-shell radiation yield; and (2) to study whether the liner resistance, its inductance and change of its inductance during implosion influence on the POS performance. The results of these experiments are presented.

  18. The Next Generation Nuclear Plant Graphite Creep Experiment Irradiation in the Advanced Test Reactor

    SciTech Connect

    Blaine Grover

    2010-10-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Program will be irradiating six gas reactor graphite creep experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the United States Department of Energy’s lead laboratory for nuclear energy development. The ATR is one of the world’s premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These graphite irradiations are being accomplished to support development of the next generation reactors in the United States. The graphite experiments will be irradiated over the next six to eight years to support development of a graphite irradiation performance data base on the new nuclear grade graphites now available for use in high temperature gas reactors. The goals of the irradiation experiments are to obtain irradiation performance data, including irradiation creep, at different temperatures and loading conditions to support design of the Next Generation Nuclear Plant (NGNP) Very High Temperature Gas Reactor, as well as other future gas reactors. The experiments will each consist of a single capsule that will contain six stacks of graphite specimens, with half of the graphite specimens in each stack under a compressive load, while the other half of the specimens will not be subjected to a compressive load during irradiation. The six stacks will have differing compressive loads applied to the top half of each pair of specimen stacks, while a seventh stack will not have a compressive load. The specimens will be irradiated in an inert sweep gas atmosphere with on-line temperature and compressive load monitoring and control. There will also be the capability of sampling the sweep gas effluent to determine if any oxidation or off-gassing of the specimens occurs during initial start-up of

  19. Measure Guideline: Evaporative Condensers

    SciTech Connect

    German, A; Dakin, B.; Hoeschele, M.

    2012-03-01

    This measure guideline on evaporative condensers provides information on properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices.

  20. Dynamic simulation recalls condensate piping event

    SciTech Connect

    Farrell, R.J.; Reneberg, K.O. ); Moy, H.C. )

    1994-05-01

    This article describes how experience gained from simulating and reconstructing a condensate piping event will be used by Consolidated Edison to analyze control system problems. A cooperative effort by Con Edison and the Chemical Engineering Department at Polytechnic University used modular modeling system to investigate the probable cause of a Con Edison condensate piping event. Con Edison commissioned the work to serve as a case study for the more general problem of control systems analysis using dynamic simulation and MMS.

  1. A high impedance mega-ampere generator for fiber z-pinch experiments

    NASA Astrophysics Data System (ADS)

    Mitchell, I. H.; Bayley, J. M.; Chittenden, J. P.; Worley, J. F.; Dangor, A. E.; Haines, M. G.; Choi, P.

    1996-04-01

    At Imperial College a mega-ampere generator for plasma implosion experiments has been designed, built, and commissioned. With a final line impedance of 1.25 Ω this terawatt class generator has been designed primarily to drive a maximum current of 1.8 MA with a rise time of 150 ns into high inductance z-pinch loads of interest to radiative collapse studies. This article describes the design and tests of the generator which has a novel configuration of lines and a new design of a magnetically insulated transmission line (MITL). In summary, the generator consists of four Marx generators each of the Hermes III type (2.4 MV, 84 kJ), each connected to 5 Ω pulse forming lines and trigatron gas switches. The power is fed into the matched 1.25 Ω vertical transfer line which feeds a diode stack and a short conical MITL in vacuum which concentrates the power into the z-pinch load. At 80% charge a current rising to 1.4 MA in 150 ns has been measured in a 15 nH inductive short. Similar results are obtained when using a plasma load.

  2. Freeze-Tolerant Condensers

    NASA Technical Reports Server (NTRS)

    Crowley, Christopher J.; Elkouhk, Nabil

    2004-01-01

    Two condensers designed for use in dissipating heat carried by working fluids feature two-phase, self-adjusting configurations such that their working lengths automatically vary to suit their input power levels and/or heat-sink temperatures. A key advantage of these condensers is that they can function even if the temperatures of their heat sinks fall below the freezing temperatures of their working fluids and the fluids freeze. The condensers can even be restarted from the frozen condition. The top part of the figure depicts the layout of the first condenser. A two-phase (liquid and vapor) condenser/vapor tube is thermally connected to a heat sink typically, a radiatively or convectively cooled metal panel. A single-phase (liquid) condensate-return tube (return artery) is also thermally connected to the heat sink. At intervals along their lengths, the condenser/vapor tube and the return artery are interconnected through porous plugs. This condenser configuration affords tolerance of freezing, variable effective thermal conductance (such that the return temperature remains nearly constant, independently of the ultimate sink temperature), and overall pressure drop smaller than it would be without the porous interconnections. An additional benefit of this configuration is that the condenser can be made to recover from the completely frozen condition either without using heaters, or else with the help of heaters much smaller than would otherwise be needed. The second condenser affords the same advantages and is based on a similar principle, but it has a different configuration that affords improved flow of working fluid, simplified construction, reduced weight, and faster recovery from a frozen condition.

  3. Femtosecond X-ray generation through 90{sup o} Thomson scattering: Status of the LBL experiment

    SciTech Connect

    Leemans, W.; Schoenlein, R.; Chin, A.; Glover, E.; Conde, M.; Chattopadhyay, S.; Kim, K.J.; Shank, C.V.

    1994-11-01

    Scattering of femotosecond laser pulses off a low energy relativistic electron beam at 90{sup o} offers the possibility to generate ultrashort X-ray pulses. Experiments are under preparation in the Beam Test Facility of the Center for Beam Physics at LBL to demonstrate the generation and detection of such pulses. The experiments involve a relativistic electron beam (tunable from 25-50 MeV) with a bunch length of 10 ps containing 1-2 nC, and an ultra short pulse (50-200 fs), high peak power (>2 TW) 0.8 {mu}m Ti:Al{sub 2}O{sub 3} laser system. The electron beam, focused down to about a 50 {mu}m waist size intersects the focused laser beam at 90{sup o}. The laser field acts as an electromagnetic undulator with strength K (quiver velocity of an electron normalized to the speed of light) for the relativistic electron beam, generating radiation up-shifted by 2{gamma}{sup 2}/(1+K{sup 2}/2) and a pulse length given by the overlapped interaction length in time of the laser beam and the electron beam. Here {gamma} is the usual Lorentz factor. Wavelength tuning will be accomplished in the experiment by generating wiggler strengths on the order of one as well as by electron beam energy tuning. For a 50 MeV electron beam and a laser beam focused to an intensity on the order of 10{sup 16} W/cm{sup 2}, the authors expect 10{sup 5} photons at 0.4 {angstrom} (10% bandwidth) in a cone angle of 6 mrad in a 170 fs pulse.

  4. Condenser on-line fouling monitor

    SciTech Connect

    Tsou, J.L.; Garey, J.F.; Wiebe, D.H.

    1994-12-31

    Biological and/or chemical fouling in utility condensers is a major cause of reduced efficiency and substantially affects availability and increases operational costs. Performance losses due to water side fouling are difficult to measure and, usually, quantitative assessment of the economic impact of condenser fouling is impossible. Plant operators typically examine steam backpressure and perform complex calculations for condenser cleanliness. These direct estimates are often imprecise due to inadequate instrumentation. In addition, these data provide information on overall condenser performance which may be influenced by a number of parameters which are independent of water side fouling. Indirect (side-stream) methods are also used to isolate/measure biological or chemical fouling in condensers. This approach is extremely useful to document site/seasonal fouling rates, and for the simultaneous evaluation of treatment options. In collaboration with the Electric Power Research Institute, instrumentation has been developed which meets requirements for the direct, on-line measurement of condenser fouling. This monitor may be installed in any location within the condenser, does not interfere with routine plant operations, including on-line mechanical and chemical treatment methods, and provides continuous, real-time readings of the heat transfer efficiency of the instrumented tube. Three prototype assemblies were installed at the New England Power Company, Brayton Point Generating Station in 1993. This paper discusses the design, construction, preliminary test results, and subsequent data collected in 1994 with a redesigned system.

  5. Pulsed-neutron techniques for condensed-matter research

    SciTech Connect

    Brown, B.S.; Carpenter, J.M.; Jorgensen, J.D.; Price, D.L.; Kamitakahara, W.

    1981-01-01

    Pulsed spallation sources are reviewed in a historical content as the latest generation of neutron sources in a line that started with the discovery of the neutron in 1932 and proceeded through research-reactor and accelerator-driven sources. The characteristics of the spallation sources are discussed in relation to their capabilities for structural and dynamical studies of condensed matter with slow neutrons and radiation effects research with fast neutrons. The new scientific opportunities opened up in these fields by the unique features of the sources are briefly reviewed, with some examples of completed work and experiments being planned.

  6. Condensed matter analogues of cosmology

    NASA Astrophysics Data System (ADS)

    Kibble, Tom; Srivastava, Ajit

    2013-10-01

    It is always exciting when developments in one branch of physics turn out to have relevance in a quite different branch. It would be hard to find two branches farther apart in terms of energy scales than early-universe cosmology and low-temperature condensed matter physics. Nevertheless ideas about the formation of topological defects during rapid phase transitions that originated in the context of the very early universe have proved remarkably fruitful when applied to a variety of condensed matter systems. The mathematical frameworks for describing these systems can be very similar. This interconnection has led to a deeper understanding of the phenomena in condensed matter systems utilizing ideas from cosmology. At the same time, one can view these condensed matter analogues as providing, at least in a limited sense, experimental access to the phenomena of the early universe for which no direct probe is possible. As this special issue well illustrates, this remains a dynamic and exciting field. The basic idea is that when a system goes through a rapid symmetry-breaking phase transition from a symmetric phase into one with spontaneously broken symmetry, the order parameter may make different choices in different regions, creating domains that when they meet can trap defects. The scale of those domains, and hence the density of defects, is constrained by the rate at which the system goes through the transition and the speed with which order parameter information propagates. This is what has come to be known as the Kibble-Zurek mechanism. The resultant scaling laws have now been tested in a considerable variety of different systems. The earliest experiments illustrating the analogy between cosmology and condensed matter were in liquid crystals, in particular on the isotropic-to-nematic transition, primarily because it is very easy to induce the phase transition (typically at room temperature) and to image precisely what is going on. This field remains one of the

  7. Alpha Condensates in Atomic Nuclei

    SciTech Connect

    Suzuki, Y.; Matsumura, H.

    2005-11-21

    Recent issues on Bose-Einstein condensation (BEC) of {alpha}-particles in nuclei are reviewed. A candidate of condensates is discussed for some states in 12C and 16O by defining the amount of {alpha} condensation.

  8. A large volume uniform plasma generator for the experiments of electromagnetic wave propagation in plasma

    SciTech Connect

    Yang Min; Li Xiaoping; Xie Kai; Liu Donglin; Liu Yanming

    2013-01-15

    A large volume uniform plasma generator is proposed for the experiments of electromagnetic (EM) wave propagation in plasma, to reproduce a 'black out' phenomenon with long duration in an environment of the ordinary laboratory. The plasma generator achieves a controllable approximate uniform plasma in volume of 260 mm Multiplication-Sign 260 mm Multiplication-Sign 180 mm without the magnetic confinement. The plasma is produced by the glow discharge, and the special discharge structure is built to bring a steady approximate uniform plasma environment in the electromagnetic wave propagation path without any other barriers. In addition, the electron density and luminosity distributions of plasma under different discharge conditions were diagnosed and experimentally investigated. Both the electron density and the plasma uniformity are directly proportional to the input power and in roughly reverse proportion to the gas pressure in the chamber. Furthermore, the experiments of electromagnetic wave propagation in plasma are conducted in this plasma generator. Blackout phenomena at GPS signal are observed under this system and the measured attenuation curve is of reasonable agreement with the theoretical one, which suggests the effectiveness of the proposed method.

  9. Critical condensate saturation in porous media

    SciTech Connect

    Wang, X.; Mohanty, K.K.

    1999-06-15

    The understanding of gas and condensate flow in porous media is critical to the optimum exploitation of gas-condensate reservoirs. Critical condensate saturation and relative permeabilities are the key parameters for the evaluation of possible recovery strategies. This work is aimed at developing a mechanistic network model for the critical condensate saturation in which phase trapping and connectivity in the pore corners are critically examined. Porous media are modeled by networks of pore bodies interconnected by pore throats. Bodies and throats are characterized by their connectivity, shapes, and radii distributions. Pore-level laws are identified from micromodel experiments with near-critical fluids. A nonzero critical condensate saturation can be obtained in the absence of contact angle hysteresis due to the converging-diverging nature of the throats. The critical saturation at which the condensate flows is found to be a function of pore geometry, water saturation, and interfacial tension (or the Bond number). The modified sphere-pack model underpredicts the critical condensate saturation of typical sandstones. The cubic model adequately predicts the critical saturation and its experimentally observed trends.

  10. Optical Spectroscopy Experiments on the 500 kA XP Pulsed-Power Generator

    SciTech Connect

    Bell, K. S.; Shelkovenko, T. A.; Pikuz, S. A.; McBride, R. D.; Blesener, I. C.; Knapp, P. F.; Hammer, D. A.; Greenly, J. B.; Maron, Y.

    2009-01-21

    Recent experiments on the 500 kA XP pulsed-power generator at Cornell University have explored the properties of optical spectra in single wires and wire arrays. In the single wire experiments, {approx}1% of the current from XP has been directed through the single wire. Spectra have been recorded using a half-meter spectrometer and a CCD camera located adjacent to the XP pulser. We are studying the visible spectra emitted by the wires and the background light from the machine hardware in order to identify the levels of current per wire for which visible spectroscopy might provide a means to measure magnetic field strength. We have also investigated the dependence of single wire visible spectra on the current, which was measured using a calibrated non-integrating Rogowski coil. UV and XUV diodes were employed to gather information about the temporal structure of the background and wire radiation. The line radiation in the spectra was recorded with wire currents at the few kA level. This is comparable to the first 10 ns of a 32-wire array experiment on 1 Ma generator and a 600-wire array at 20 MA.

  11. Next Generation Climate Change Experiments Needed to Advance Knowledge and for Assessment of CMIP6

    SciTech Connect

    Katzenberger, John; Arnott, James; Wright, Alyson

    2014-10-30

    The Aspen Global Change Institute hosted a technical science workshop entitled, “Next generation climate change experiments needed to advance knowledge and for assessment of CMIP6,” on August 4-9, 2013 in Aspen, CO. Jerry Meehl (NCAR), Richard Moss (PNNL), and Karl Taylor (LLNL) served as co-chairs for the workshop which included the participation of 32 scientists representing most of the major climate modeling centers for a total of 160 participant days. In August 2013, AGCI gathered a high level meeting of representatives from major climate modeling centers around the world to assess achievements and lessons learned from the most recent generation of coordinated modeling experiments known as the Coupled Model Intercomparison Project – 5 (CMIP5) as well as to scope out the science questions and coordination structure desired for the next anticipated phase of modeling experiments called CMIP6. The workshop allowed for reflection on the coordination of the CMIP5 process as well as intercomparison of model results, such as were assessed in the most recent IPCC 5th Assessment Report, Working Group 1. For example, this slide from Masahiro Watanabe examines performance on a range of models capturing Atlantic Meridional Overturning Circulation (AMOC).

  12. GAS-GENERATION EXPERIMENTS FOR LONG-TERM STORAGE OF TRU WASTES AT WIPP

    SciTech Connect

    Felicione, F.S.; Carney, K.P.; Dwight, C.C.; Cummings, D.G.; Foulkrod, L.E.

    2003-02-27

    An experimental investigation was conducted for gas generation in contact-handled transuranic (CH-TRU) wastes subjected for several years to conditions similar to those expected to occur at the Waste Isolation Pilot Plant (WIPP) should the repository eventually become inundated with brine. Various types of actual CH-TRU wastes were placed into 12 corrosion-resistant vessels. The vessels were loosely filled with the wastes, which were submerged in synthetic brine having the same chemical composition as that in the WIPP vicinity. The vessels were also inoculated with microbes found in the Salado Formation at WIPP. The vessels were sealed, purged, and the approximately 750-ml headspace was pressurized with nitrogen gas to approximately 146 atmospheres to create anoxic conditions at the lithostatic pressure expected in the repository were it inundated. The temperature was maintained at the expected 30 C. The test program objective was to measure the quantities and species of gases generate d by metal corrosion, radiolysis, and microbial activity. These data will assist in the specification of the rates at which gases are produced under inundated repository conditions for use in the WIPP Performance Assessment computer models. These experiments were very carefully designed, constructed, instrumented, and performed. Approximately 6-1/2 years of continuous, undisturbed testing were accumulated. Several of the vessels showed significantly elevated levels of generated gases, virtually all of which was hydrogen. One vessel measured over 4.2% hydrogen, by volume. Two other vessels generated well over 1% hydrogen, and another was at nearly 1%. Only small quantities of other gases, principally carbon dioxide, were detected. Gas generation was found to depend strongly on the waste composition. The maximum hydrogen generation occurred in tests containing carbon steel. Average corrosion penetration rates in carbon-steel of up to 2.3 microns per year were deduced. Conversion of

  13. Sedimentary condensation and authigenesis

    NASA Astrophysics Data System (ADS)

    Föllmi, Karl

    2016-04-01

    Most marine authigenic minerals form in sediments, which are subjected to condensation. Condensation processes lead to the formation of well individualized, extremely thin (< 1m) beds, which were accumulated during extremely long time periods (> 100ky), and which experienced authigenesis and the precipitation of glaucony, verdine, phosphate, iron and manganese oxyhydroxides, iron sulfide, carbonate and/or silica. They usually show complex internal stratigraphies, which result from an interplay of sediment accumulation, halts in sedimentation, sediment winnowing, erosion, reworking and bypass. They may include amalgamated faunas of different origin and age. Hardgrounds may be part of condensed beds and may embody strongly condensed beds by themselves. Sedimentary condensation is the result of a hydrodynamically active depositional regime, in which sediment accumulation, winnowing, erosion, reworking and bypass are processes, which alternate as a function of changes in the location and intensity of currents, and/or as the result of episodic high-energy events engendered by storms and gravity flow. Sedimentary condensation has been and still is a widespread phenomenon in past and present-day oceans. The present-day distribution of glaucony and verdine-rich sediments on shelves and upper slopes, phosphate-rich sediments and phosphorite on outer shelves and upper slopes, ferromanganese crusts on slopes, seamounts and submarine plateaus, and ferromanganese nodules on abyssal seafloors is a good indication of the importance of condensation processes today. In the past, we may add the occurrence of oolitic ironstone, carbonate hardgrounds, and eventually also silica layers in banded iron formations as indicators of the importance of condensation processes. Besides their economic value, condensed sediments are useful both as a carrier of geochemical proxies of paleoceanographic and paleoenvironmental change, as well as the product of episodes of paleoceanographic and

  14. Self-generated magnetic fields in blast-wave driven Rayleigh-Taylor experiments

    NASA Astrophysics Data System (ADS)

    Flaig, Markus; Plewa, Tomasz

    2015-12-01

    We study the effect of self-generated magnetic fields in two-dimensional computer models of blast-wave driven high-energy density Rayleigh-Taylor instability (RTI) experiments. Previous works [1,2] suggested that such fields have the potential to influence the RTI morphology and mixing. When neglecting the friction force between electrons and ions, we do indeed find that dynamically important (β≲103) magnetic fields are generated. However, in the more realistic case where the friction force is accounted for, the resulting fields are much weaker, β≳105 , and can no longer influence the dynamics of the system. Although we find no evidence for dynamically important magnetic fields being created in the two-dimensional case studied here, the situation might be different in a three-dimensional setup, which will be addressed in a future study.

  15. Preliminary experiments on the noise generated by target-type thrust reverser models

    NASA Technical Reports Server (NTRS)

    Gutierrez, O. A.; Stone, J. R.

    1972-01-01

    Experiments are reported on the noise generated by model V-gutter and semicylindrical target-type reversers with circular nozzles. Nozzles were 5.24 and 7.78 cm in diameter. Nozzle pressure ratio ranged from 1.25 to 1.72. The spacing between reversers and nozzle, as well as the reverser orientation, was also varied. More noise was generated with reversers than with the nozzle alone. The measured maximum overall sound pressure level varied with the sixth power of the nozzle exit velocity. Noise levels were more uniform in regard to directivity with reversers than with the nozzle alone. It is concluded that thrust reversers, can be a significant noise problem, especially for STOL aircraft using thrust reversers during approach.

  16. A 7 T Pulsed Magnetic Field Generator for Magnetized Laser Plasma Experiments

    NASA Astrophysics Data System (ADS)

    Hu, Guangyue; Liang, Yihan; Song, Falun; Yuan, Peng; Wang, Yulin; Zhao, Bin; Zheng, Jian

    2015-02-01

    A pulsed magnetic field generator was developed to study the effect of a magnetic field on the evolution of a laser-generated plasma. A 40 kV pulsed power system delivered a fast (~230 ns), 55 kA current pulse into a single-turn coil surrounding the laser target, using a capacitor bank of 200 nF, a laser-triggered switch and a low-impedance strip transmission line. A one-dimensional uniform 7 T pulsed magnetic field was created using a Helmholtz coil pair with a 6 mm diameter. The pulsed magnetic field was controlled to take effect synchronously with a nanosecond heating laser beam, a femtosecond probing laser beam and an optical Intensified Charge Coupled Device (ICCD) detector. The preliminary experiments demonstrate bifurcation and focusing of plasma expansion in a transverse magnetic field.

  17. Electrolyte vapor condenser

    DOEpatents

    Sederquist, Richard A.; Szydlowski, Donald F.; Sawyer, Richard D.

    1983-01-01

    A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well.

  18. Electrolyte vapor condenser

    DOEpatents

    Sederquist, R.A.; Szydlowski, D.F.; Sawyer, R.D.

    1983-02-08

    A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well. 3 figs.

  19. Pore-space alteration in source rock (shales) during hydrocarbons generation: laboratory experiment

    NASA Astrophysics Data System (ADS)

    Giliazetdinova, D. R.; Korost, D. V.; Nadezhkin, D. V.

    2013-12-01

    Hydrocarbons (HC) are generated from solid organic matter (kerogen) due to thermocatalytic reactions. The rate of such reactions shows direct correlation with temperature and depends on the depth of source rock burial. Burial of sedimentary rock is also inevitably accompanied by its structural alteration owing to compaction, dehydration and re-crystallization. Processes of HC generation, primary migration and structural changes are inaccessible for direct observation in nature, but they can be studied in laboratory experiments. Experiment was carried out with a clayey-carbonate rock sample of the Domanik Horizon taken from boreholes drilled in the northeastern part of the south Tatar arch. The rock chosen fits the very essential requirements - high organic matter content and its low metamorphic grade. Our work aimed at laboratory modeling of HC generation in an undisturbed rock sample by its heating in nitrogen atmosphere based on a specified temperature regime and monitoring alterations in the pore space structure. Observations were carried out with a SkyScan-1172 X-ray microtomography scanner (resulting scan resolution of 1 μm). A cylinder, 44 mm in diameter, was prepared from the rock sample for the pyrolitic and microtomographic analyses. Scanning procedures were carried out in 5 runs. Temperature interval for each run had to match the most important stage of HC generation in the source rock, namely: (1) original structure; (2) 100-300°C - discharge of free and adsorbed HC and water; (3) 300-400°C - initial stage of HC formation owing to high-temperature pyrolysis of the solid organic matter and discharge of the chemically bound water; (4) 400-470°C - temperature interval fitting the most intense stage of HC formation; (5) 470-510°C - final stage of HC formation. Maximum sample heating in the experiment was determined as temperature of the onset of active decomposition of carbonates, i.e., in essence, irreversible metamorphism of the rock. Additional

  20. Wire array experiments in a low impedance and low current generator

    NASA Astrophysics Data System (ADS)

    Cabrini, Nibaldo; Pavez, Cristian; Avaria, Gonzalo; San Martin, Patricio; Veloso, Felipe; Zúñiga, Barbara; Sepúlveda, Adolfo; Soto, Leopoldo

    2015-03-01

    In this work, a preliminary study about the behavior of a low impedance generator on different wire array configurations is reported. The experimental measurements were carried out on a small multi-purpose generator (1.2μF, 345J, 47.5nH, T/4 = 375 ns and Z = 0.2Ω in short circuit) which produces currents up to 122 kA with 500 ns quarter period, when a charging voltage of 24kV and a wire load are used. Two types of configurations were tested: parallel wires (two and four) and X-pinch configurations. The experiments were carried out on W, Al, and Cu wires with different diameters. The discharge was characterized by means of a set of diagnostics which included: Rogowski coil; filtered PCD detector; filtered PIN diode; gated VUV/soft X-ray pinhole camera, Shadow diagnostic and dark field Schlieren technique. From the set of experimental results, the following observations can be established: (i) The generator is highly sensitive to the changes of load impedance due to its low impedance design. (ii) Every shot shows a dip in the current derivative signal shortly after the discharge onset time (from 6 to 40 ns), which is inversely related to the load resistance. (iii) Both configurations show a similar dynamic to those observed in experiments of higher current and shorter quarter period. (iv) At the X-pinch experiments, two or more hard X-ray bursts are detected, around 200 ns from the current onset time. These X-ray bursts are correlated with the dips observed in the current derivative signal.

  1. Experiment and simulations of sub-ps electron bunch train generation at Fermilab photoinjectors

    SciTech Connect

    Sun, Y.-E; Church, M.; Piot, P.; Prokop, C.R.; /Fermilab /Northern Illinois U.

    2011-10-01

    Recently the generation of electron bunch trains with sub-picosecond time structure has been experimentally demonstrated at the A0 photoinjector of Fermilab using a transverse-longitudinal phase-space exchange beamline. The temporal profile of the bunch train can be easily tuned to meet the requirements of the applications of modern accelerator beams. In this paper we report the A0 bunch-train experiment and explore numerically the possible extension of this technique to shorter time scales at the Fermilab SRF Accelerator Test Facility, a superconducting linear electron accelerator currently under construction in the NML building.

  2. Magnetic field measurements of a superconducting undulator for a Harmonic Generation FEL experiment at the NSLS

    SciTech Connect

    Solomon, L.; Ingold, G.; Ben-Zvi, I.; Krinsky, S.; Yu, L.H.; Sampson, W.; Robins, K.

    1993-07-01

    An 18mm period, 0.54 Tesla, 8mm gap superconducting undulator with both horizontal and vertical focusing has been built and tested. This magnet, which is fabricated in 25 cm length sections, is being tested for use in the radiator section (total magnet length of 1.5 m) of the Harmonic Generation Free Electron Laser experiment at the National Synchrotron Light Source - Accelerator Test Facility at Brookhaven National Lab., in collaboration with Grumman Corp. The measurement system is outlined, sources and estimates of errors are described, and some magnetic field data are presented and discussed.

  3. Collisional Dynamics of Half-Quantum Vortices in a Spinor Bose-Einstein Condensate.

    PubMed

    Seo, Sang Won; Kwon, Woo Jin; Kang, Seji; Shin, Y

    2016-05-01

    We present an experimental study on the interaction and dynamics of half-quantum vortices (HQVs) in an antiferromagnetic spinor Bose-Einstein condensate. By exploiting the orbit motion of a vortex dipole in a trapped condensate, we perform a collision experiment of two HQV pairs, and observe that the scattering motions of the HQVs is consistent with the short-range vortex interaction that arises from nonsingular magnetized vortex cores. We also investigate the relaxation dynamics of turbulent condensates containing many HQVs, and demonstrate that spin wave excitations are generated by the collisional motions of the HQVs. The short-range vortex interaction and the HQV-magnon coupling represent two characteristics of the HQV dynamics in the spinor superfluid. PMID:27203331

  4. Collisional Dynamics of Half-Quantum Vortices in a Spinor Bose-Einstein Condensate

    NASA Astrophysics Data System (ADS)

    Seo, Sang Won; Kwon, Woo Jin; Kang, Seji; Shin, Y.

    2016-05-01

    We present an experimental study on the interaction and dynamics of half-quantum vortices (HQVs) in an antiferromagnetic spinor Bose-Einstein condensate. By exploiting the orbit motion of a vortex dipole in a trapped condensate, we perform a collision experiment of two HQV pairs, and observe that the scattering motions of the HQVs is consistent with the short-range vortex interaction that arises from nonsingular magnetized vortex cores. We also investigate the relaxation dynamics of turbulent condensates containing many HQVs, and demonstrate that spin wave excitations are generated by the collisional motions of the HQVs. The short-range vortex interaction and the HQV-magnon coupling represent two characteristics of the HQV dynamics in the spinor superfluid.

  5. Condensation on Slippery Asymmetric Bumps

    NASA Astrophysics Data System (ADS)

    Park, Kyoo-Chul; Kim, Philseok; Aizenberg, Joanna

    Controlling dropwise condensation by designing surfaces that enable droplets to grow rapidly and be shed as quickly as possible is fundamental to water harvesting systems, thermal power generation, distillation towers, etc. However, cutting-edge approaches based on micro/nanoscale textures suffer from intrinsic trade-offs that make it difficult to optimize both growth and transport at once. Here we present a conceptually different design approach based on principles derived from Namib desert beetles, cacti, and pitcher plants that synergistically couples both aspects of condensation and outperforms other synthetic surfaces. Inspired by an unconventional interpretation of the role of the beetle's bump geometry in promoting condensation, we show how to maximize vapor diffusion flux at the apex of convex millimetric bumps by optimizing curvature and shape. Integrating this apex geometry with a widening slope analogous to cactus spines couples rapid drop growth with fast directional transport, by creating a free energy profile that drives the drop down the slope. This coupling is further enhanced by a slippery, pitcher plant-inspired coating that facilitates feedback between coalescence-driven growth and capillary-driven motion. We further observe an unprecedented six-fold higher exponent in growth rate and much faster shedding time compared to other surfaces. We envision that our fundamental understanding and rational design strategy can be applied to a wide range of phase change applications.

  6. Rainfall simulation experiments with a small portable rainfall simulator: research on runoff generation and soil erosion

    NASA Astrophysics Data System (ADS)

    Iserloh, Thomas; Peter, Klaus Daniel; Fister, Wolfgang; Wirtz, Stefan; Butzen, Verena; Brings, Christine; Marzen, Miriam; Casper, Markus C.; Seeger, Manuel; Ries, Johannes B.

    2015-04-01

    The results of more than 500 rainfall simulations with a small portable rainfall simulator at various locations in West and North Africa and South and Central Europe will be presented. The analysis of this comprehensive database offers results concerning different research objectives: - erodibility of local soils regarding different vegetation cover, stone cover and land uses - runoff generation in gully catchments - process oriented experiments on the influence of sealing and crusting - trail erosion caused by goat- or sheep-trampling - recent erosion on geomorphological forms Runoff coefficients range from 0 to 100 % and eroded material from 0 to 500 g m^-2 during 30 min experiments with a rainfall intensity of 40 mm h^-1.

  7. Monochromatic radiography of high energy density physics experiments on the MAGPIE generator

    SciTech Connect

    Hall, G. N. Burdiak, G. C.; Suttle, L.; Stuart, N. H.; Swadling, G. F.; Lebedev, S. V.; Smith, R. A.; Patankar, S.; Suzuki-Vidal, F.; Grouchy, P. de; Harvey-Thompson, A. J.; Bennett, M.; Bland, S. N.; Pickworth, L.; Skidmore, J.

    2014-11-15

    A monochromatic X-ray backlighter based on Bragg reflection from a spherically bent quartz crystal has been developed for the MAGPIE pulsed power generator at Imperial College (1.4 MA, 240 ns) [I. H. Mitchell et al., Rev. Sci. Instrum. 67, 1533 (2005)]. This instrument has been used to diagnose high energy density physics experiments with 1.865 keV radiation (Silicon He-α) from a laser plasma source driven by a ∼7 J, 1 ns pulse from the Cerberus laser. The design of the diagnostic, its characterisation and performance, and initial results in which the instrument was used to radiograph a shock physics experiment on MAGPIE are discussed.

  8. Magnons in a box: Condensation and Application

    NASA Astrophysics Data System (ADS)

    Fang, Fang; Olf, Ryan; Wu, Shun; Kadau, Holger; Marti, G. Edward; Stamper-Kurn, Dan

    2016-05-01

    Ultracold gases offer us a remarkable window into the quantum world, allowing direct access to a wide range of manybody and condensed matter phenomena at convenient macroscopic length and time scales. However, producing ultracold gases at ever lower entropy, and measuring statistical properties such as temperature in these low entropy regimes, is a persistent challenge. Magnons, gapless spin excitations of spinor Bose Einstein Condensate (BEC), are expected to behave like free particles. We show that magnons can be used to cool BEC in a deep trap and serve as a thermometer to measure temperatures at extremely low entropy-per-particle. Unlike atoms trapped in a harmonic trap, trapped magnons experience a box potential due to near exact cancellation of the trapping potential by the mean-field interaction within the condensate. We observe the quasi-condensation of magnon excitations within this nature-made box.

  9. New generation of double beta decay experiments: are there any limitations?

    SciTech Connect

    Barabash, A. S.

    2011-12-16

    New generation of experiments to search for neutrinoless double beta decay with sensitivity to effective Majorana neutrino mass on the level of {approx}3-5 meV is discussed. Possible restrictions in achievement of this sensitivity such as: possibility to produce large amount of enriched isotopes, possibility to reach of a very low level of background, energy resolution and possible cost of experiments are considered. It is shown that for realization of so ambitious project 10 tons (or more) of enriched isotope is required. Background index should be on the level {<=}10{sup -5}-10{sup -6} c/kg{center_dot}keV{center_dot}y. In addition, the energy resolution of the detector should be no worse than 1-2%. It is shown that {sup 130}TeO{sub 2} low temperature bolometer could be the most realistic candidate for such an experiment. Under certain conditions experiments with {sup 76}Ge, {sup 100}Mo and {sup 136}Xe can be realized too.

  10. Next Generation PanDA Pilot for ATLAS and Other Experiments

    NASA Astrophysics Data System (ADS)

    Nilsson, P.; Barreiro Megino, F.; Caballero Bejar, J.; De, K.; Hover, J.; Love, P.; Maeno, T.; Medrano Llamas, R.; Walker, R.; Wenaus, T.; Atlas Collaboration

    2014-06-01

    The Production and Distributed Analysis system (PanDA) has been in use in the ATLAS Experiment since 2005. It uses a sophisticated pilot system to execute submitted jobs on the worker nodes. While originally designed for ATLAS, the PanDA Pilot has recently been refactored to facilitate use outside of ATLAS. Experiments are now handled as plug-ins such that a new PanDA Pilot user only has to implement a set of prototyped methods in the plug-in classes, and provide a script that configures and runs the experiment-specific payload. We will give an overview of the Next Generation PanDA Pilot system and will present major features and recent improvements including live user payload debugging, data access via the Federated XRootD system, stage-out to alternative storage elements, support for the new ATLAS DDM system (Rucio), and an improved integration with glExec, as well as a description of the experiment-specific plug-in classes. The performance of the pilot system in processing LHC data on the OSG, LCG and Nordugrid infrastructures used by ATLAS will also be presented. We will describe plans for future development on the time scale of the next few years.

  11. Using the constrained DFT approach in generating diabatic surfaces and off diagonal empirical valence bond terms for modeling reactions in condensed phases.

    PubMed

    Hong, Gongyi; Rosta, Edina; Warshel, Arieh

    2006-10-01

    The empirical valence bond (EVB) model provides an extremely powerful way for modeling and analyzing chemical reactions in solutions and proteins. However, this model is based on the unverified assumption that the off diagonal elements of the EVB Hamiltonian do not change significantly upon transfer of the reacting system from one phase to another. This ad hoc assumption has been rationalized by its consistency with empirically observed linear free energy relationships, as well as by other qualitative considerations. Nevertheless, this assumption has not been rigorously established. The present work explores the validity of the above EVB key assumption by a rigorous numerical approach. This is done by exploiting the ability of the frozen density functional theory (FDFT) and the constrained density functional theory (CDFT) models to generate convenient diabatic states for QM/MM treatments, and thus to examine the relationship between the diabatic and adiabatic surfaces, as well as the corresponding effective off diagonal elements. It is found that, at least for the test case of S(N)()2 reactions, the off diagonal element does not change significantly upon moving from the gas phase to solutions and thus the EVB assumption is valid and extremely useful. PMID:17004821

  12. Ghost condensate busting

    SciTech Connect

    Bilic, Neven; Tupper, Gary B; Viollier, Raoul D E-mail: gary.tupper@uct.ac.za

    2008-09-15

    Applying the Thomas-Fermi approximation to renormalizable field theories, we construct ghost condensation models that are free of the instabilities associated with violations of the null-energy condition.

  13. Molten salt steam generator subsystem research experiment. Volume I. Phase 1 - Final report

    SciTech Connect

    1984-10-01

    A study was conducted for Phase 1 of a two-phase project whose objectives were to develop a reliable, cost-effective molten salt steam generating subsystem for solar thermal plants, minimize uncertainty in capital, operating, and maintenance costs, and demonstrate the ability of molten salt to generate high-pressure, high-temperature steam. The Phase 1 study involved the conceptual design of molten salt steam generating subsystems for a nominal 100-MWe net stand-alone solar central receiver electric generating plant, and a nominal 100-MWe net hybrid fossil-fueled electric power generating plant that is 50% repowered by a solar central receiver system. As part of Phase 1, a proposal was prepared for Phase 2, which involves the design, construction, testing and evaluation of a Subsystem Research Experiment of sufficient size to ensure successful operation of the full-size subsystem designed in Phase 1. Evaluation of several concepts resulted in the selection of a four-component (preheater, evaporator, superheater, reheater), natural circulation, vertically oriented, shell and tube (straight) heat exchanger arrangement. Thermal hydraulic analysis of the system included full and part load performance, circulation requirements, stability, and critical heat flux analysis. Flow-induced tube vibration, tube buckling, fatigue evaluation of tubesheet junctions, steady-state tubesheet analysis, and a simplified transient analysis were included in the structural analysis of the system. Operating modes and system dynamic response to load changes were identified. Auxiliary equipment, fabrication, erection, and maintenance requirements were also defined. Installed capital costs and a project schedule were prepared for each design.

  14. Critical view to ``IGEX 76Ge neutrinoless double-beta decay experiment: Prospects for next generation experiments''

    NASA Astrophysics Data System (ADS)

    Klapdor-Kleingrothaus, H. V.; Dietz, A.; Krivosheina, I. V.

    2004-10-01

    Recently, a paper entitled “The IGEX 76Ge neutrinoless double-beta decay experiment: Prospects for next generation experiments” has been published [

    Phys. Rev. D 65, 092007 (2002)PRVDAQ0556-282110.1103/PhysRevD.65.092007
    ]. In view of the recently reported evidence for neutrinoless double-beta decay [
    Mod. Phys. Lett. A 16, 2409 (2001).MPLAEQ0217-732310.1142/S0217732301005825
    ;
    Found. Phys.FNDPA40015-9018 31, 1181 (2002)
    ;
    Phys. Lett. BPYLBAJ0370-2693 586, 198 (2004).10.1016/j.physletb.2004.02.025
    ], it is particularly unfortunate that the IGEX paper is rather incomplete in its presentation. We would like to point out in this Comment that and why it would be highly desirable to make more details about the experimental conditions and the analysis of IGEX available. We list some of the main points, which require further explanation. We also point to an arithmetic mistake in the analysis of the IGEX data, the consequence of which are too high half-life limits given in that paper.

  15. Measure Guideline: Evaporative Condensers

    SciTech Connect

    German, A.; Dakin, B.; Hoeschele, M.

    2012-03-01

    The purpose of this measure guideline on evaporative condensers is to provide information on a cost-effective solution for energy and demand savings in homes with cooling loads. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices. This document has been prepared to provide a process for properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs.

  16. Observation Platforms and Data Streams of the Arctic Next Generation Ecosystem Experiment (NGEE-Arctic)

    NASA Astrophysics Data System (ADS)

    Hinzman, L. D.; Wullschleger, S. D.; Graham, D. E.; Hubbard, S. S.; Norby, R. J.; Rogers, A.; Torn, M. S.; Wilson, C. J.

    2013-12-01

    The goal of the Arctic Next Generation Ecosystem Experiment (NGEE-Arctic) is to deliver a process-rich ecosystem model, extending from bedrock to the top of the vegetative canopy, in which the evolution of Arctic ecosystems in a changing climate can be modeled at the scale of a high resolution Earth System Model grid cell. Increasing our confidence in climate projections for high-latitude regions of the world requires a coordinated set of observation platforms that target improved process understanding and model representation of important ecosystem-climate feedbacks. The Next-Generation Ecosystem Experiments (NGEE Arctic) seeks to address this challenge by quantifying the physical, chemical, and biological behavior of terrestrial ecosystems in Alaska. Initial research has focused upon the highly dynamic landscapes of the North Slope (Barrow, Alaska) where thaw lakes, drained thaw lake basins, and ice-rich polygonal ground offer distinct land units for investigation and modeling. This vision includes mechanistic studies in the field and in the laboratory; modeling of critical and interrelated water, nitrogen, carbon, and energy dynamics; and characterization of important interactions from molecular to landscape scales that drive feedbacks to the climate system. To complete these investigations, an integrated program of field monitoring has been initiated. These include observations of meteorological, hydrological, ecological and geophysical processes. These data streams are intended to supplement and extend existing polar data sets to advance our understanding of the Arctic environment and its response to a rapidly changing climate.

  17. Condensate dark matter stars

    SciTech Connect

    Li, X.Y.; Harko, T.; Cheng, K.S. E-mail: harko@hkucc.hku.hk

    2012-06-01

    We investigate the structure and stability properties of compact astrophysical objects that may be formed from the Bose-Einstein condensation of dark matter. Once the critical temperature of a boson gas is less than the critical temperature, a Bose-Einstein Condensation process can always take place during the cosmic history of the universe. Therefore we model the dark matter inside the star as a Bose-Einstein condensate. In the condensate dark matter star model, the dark matter equation of state can be described by a polytropic equation of state, with polytropic index equal to one. We derive the basic general relativistic equations describing the equilibrium structure of the condensate dark matter star with spherically symmetric static geometry. The structure equations of the condensate dark matter stars are studied numerically. The critical mass and radius of the dark matter star are given by M{sub crit} ≈ 2(l{sub a}/1fm){sup 1/2}(m{sub χ}/1 GeV){sup −3/2}M{sub s}un and R{sub crit} ≈ 1.1 × 10{sup 6}(l{sub a}/1 fm){sup 1/2}(m{sub χ}/1 GeV){sup −3/2} cm respectively, where l{sub a} and m{sub χ} are the scattering length and the mass of dark matter particle, respectively.

  18. CODEX: a next-generation sequencing experiment database for the haematopoietic and embryonic stem cell communities.

    PubMed

    Sánchez-Castillo, Manuel; Ruau, David; Wilkinson, Adam C; Ng, Felicia S L; Hannah, Rebecca; Diamanti, Evangelia; Lombard, Patrick; Wilson, Nicola K; Gottgens, Berthold

    2015-01-01

    CODEX (http://codex.stemcells.cam.ac.uk/) is a user-friendly database for the direct access and interrogation of publicly available next-generation sequencing (NGS) data, specifically aimed at experimental biologists. In an era of multi-centre genomic dataset generation, CODEX provides a single database where these samples are collected, uniformly processed and vetted. The main drive of CODEX is to provide the wider scientific community with instant access to high-quality NGS data, which, irrespective of the publishing laboratory, is directly comparable. CODEX allows users to immediately visualize or download processed datasets, or compare user-generated data against the database's cumulative knowledge-base. CODEX contains four types of NGS experiments: transcription factor chromatin immunoprecipitation coupled to high-throughput sequencing (ChIP-Seq), histone modification ChIP-Seq, DNase-Seq and RNA-Seq. These are largely encompassed within two specialized repositories, HAEMCODE and ESCODE, which are focused on haematopoiesis and embryonic stem cell samples, respectively. To date, CODEX contains over 1000 samples, including 221 unique TFs and 93 unique cell types. CODEX therefore provides one of the most complete resources of publicly available NGS data for the direct interrogation of transcriptional programmes that regulate cellular identity and fate in the context of mammalian development, homeostasis and disease. PMID:25270877

  19. Dynamics of Adaptation and Diversification: A 10,000-Generation Experiment with Bacterial Populations

    NASA Astrophysics Data System (ADS)

    Lenski, Richard E.; Travisano, Michael

    1994-07-01

    We followed evolutionary change in 12 populations of Escherichia coli propagated for 10,000 generations in identical environments. Both morphology (cell size) and fitness (measured in competition with the ancestor) evolved rapidly for the first 2000 generations or so after the populations were introduced into the experimental environment, but both were nearly static for the last 5000 generations. Although evolving in identical environments, the replicate populations diverged significantly from one another in both morphology and mean fitness. The divergence in mean fitness was sustained and implies that the populations have approached different fitness peaks of unequal height in the adaptive landscape. Although the experimental time scale and environment were microevolutionary in scope, our experiments were designed to address questions concerning the origin as well as the fate of genetic and phenotypic novelties, the repeatability of adaptation, the diversification of lineages, and thus the causes and consequences of the uniqueness of evolutionary history. In fact, we observed several hallmarks of macroevolutionary dynamics, including periods of rapid evolution and stasis, altered functional relationships between traits, and concordance of anagenetic and cladogenetic trends. Our results support a Wrightian interpretation, in which chance events (mutation and drift) play an important role in adaptive evolution, as do the complex genetic interactions that underlie the structure of organisms.

  20. CODEX: a next-generation sequencing experiment database for the haematopoietic and embryonic stem cell communities

    PubMed Central

    Sánchez-Castillo, Manuel; Ruau, David; Wilkinson, Adam C.; Ng, Felicia S.L.; Hannah, Rebecca; Diamanti, Evangelia; Lombard, Patrick; Wilson, Nicola K.; Gottgens, Berthold

    2015-01-01

    CODEX (http://codex.stemcells.cam.ac.uk/) is a user-friendly database for the direct access and interrogation of publicly available next-generation sequencing (NGS) data, specifically aimed at experimental biologists. In an era of multi-centre genomic dataset generation, CODEX provides a single database where these samples are collected, uniformly processed and vetted. The main drive of CODEX is to provide the wider scientific community with instant access to high-quality NGS data, which, irrespective of the publishing laboratory, is directly comparable. CODEX allows users to immediately visualize or download processed datasets, or compare user-generated data against the database's cumulative knowledge-base. CODEX contains four types of NGS experiments: transcription factor chromatin immunoprecipitation coupled to high-throughput sequencing (ChIP-Seq), histone modification ChIP-Seq, DNase-Seq and RNA-Seq. These are largely encompassed within two specialized repositories, HAEMCODE and ESCODE, which are focused on haematopoiesis and embryonic stem cell samples, respectively. To date, CODEX contains over 1000 samples, including 221 unique TFs and 93 unique cell types. CODEX therefore provides one of the most complete resources of publicly available NGS data for the direct interrogation of transcriptional programmes that regulate cellular identity and fate in the context of mammalian development, homeostasis and disease. PMID:25270877

  1. Hydroclast and Peperite generation: Experimental Results produced using the Silicate Melt Injection Laboratory Experiment

    NASA Astrophysics Data System (ADS)

    Downey, W. S.; Mastin, L. G.; Spieler, O.; Kunzmann, T.; Shaw, C. S.; Dingwell, D. B.

    2008-12-01

    The Silicate Melt Injection Laboratory Experiment (SMILE) allows for the effusive and explosive injection of molten glass into a variety of media - air, water, water spray, and wet sediments. Experiments have been preformed using the SMILE apparatus to evaluate the mechanisms of "turbulent shedding" during shallow submarine volcanic eruptions and magma/wet-sediment interactions. In these experiments, approximately 0.5 kg of basaltic melt with 5 wt.% Spectromelt (dilithium tetraborate) is produced in an internally heated autoclave at 1150° C and ambient pressure. The molten charge is ejected via the bursting of a rupture disc at 3.5 MPa into the reaction media, situated within the low pressure tank (atmospheric conditions). Preliminary experiments ejecting melt into a standing water column have yielded hydroclasts of basalt. SEM images of the clasts show ubiquitous discontinuous skins ("rinds") that are flaked, peeled, or smeared away in strips. Adhering to the clast surfaces are flakes, blocks, and blobs of detached material, up to 10 μm in size. The presence of partially detached rinds and rind debris likely reflects repeated bending, scraping, impact, and other disruption through turbulent velocity fluctuations. These textures are comparable to littoral explosive deposits at Kilauea Volcano, Hawaii, where lava tubes are torn apart by wave action, the lava is quenched, and thrown back on the beach as loose fragments (hyaloclastite). Preliminary experiments injecting melt into wet sediments show evidence of sediment ingestion and fluidal textures. These results support the interpretation that peperite generation can be driven by hydrodynamic mixing of a fuel and a coolant.

  2. Analyses of internal tides generation and propagation over a Gaussian ridge in laboratory and numerical experiments

    NASA Astrophysics Data System (ADS)

    Dossmann, Yvan; Paci, Alexandre; Auclair, Francis; Floor, Jochem

    2010-05-01

    Internal tides are suggested to play a major role in the sustaining of the global oceanic circulation [1][5]. Although the exact origin of the energy conversions occurring in stratified fluids is questioned [2], it is clear that the diapycnal energy transfers provided by the energy cascade of internal gravity waves generated at tidal frequencies in regions of steep bathymetry is strongly linked to the general circulation energy balance. Therefore a precise quantification of the energy supply by internal waves is a crucial step in forecasting climate, since it improves our understanding of the underlying physical processes. We focus on an academic case of internal waves generated over an oceanic ridge in a linearly stratified fluid. In order to accurately quantify the diapycnal energy transfers caused by internal waves dynamics, we adopt a complementary approach involving both laboratory and numerical experiments. The laboratory experiments are conducted in a 4m long tank of the CNRM-GAME fluid mechanics laboratory, well known for its large stratified water flume (e.g. Knigge et al [3]). The horizontal oscillation at precisely controlled frequency of a Gaussian ridge immersed in a linearly stratified fluid generates internal gravity waves. The ridge of e-folding width 3.6 cm is 10 cm high and spans 50 cm. We use PIV and Synthetic Schlieren measurement techniques, to retrieve the high resolution velocity and stratification anomaly fields in the 2D vertical plane across the ridge. These experiments allow us to get access to real and exhaustive measurements of a wide range of internal waves regimes by varying the precisely controlled experimental parameters. To complete this work, we carry out some direct numerical simulations with the same parameters (forcing amplitude and frequency, initial stratification, boundary conditions) as the laboratory experiments. The model used is a non-hydrostatic version of the numerical model Symphonie [4]. Our purpose is not only to

  3. The Mirrortron experiment: A proof of principle test for a method of generating high transient potentials

    SciTech Connect

    Douglass, S.R.

    1993-09-01

    The Mirrortron is a concept in which heavy ions are accelerated by a large local transient space potential that is produced in a hot electron plasma. The purpose of this experiment is to begin a proof of principle experiment to investigate the feasibility of producing this space potential and its associated electric field. If a large magnetic field is suddenly generated in a hot electron plasma with a loss-cone distribution, then potentials on the order of the electron temperature are expected. This potential lasts a few tens of nanoseconds. The investigation begins with a theoretical analysis of this phenomenon giving the space potential as a function of the applied magnetic field. The theory is further extended to cases of relativistic electron distributions. This is then followed by design work on a mirror confinement system for hot electrons. In this experiment a 50--100 keV electron temperature plasma is created with electron cyclotron resonance heating using two frequencies of relatively low microwave power. The microwaves are coupled to resonant frequencies of the vacuum chamber. The volume averaged plasma density is measured to be in the 10{sup 9} cm{sup {minus}3} range. A strap coil and a flat Blumlein transmission line pulse generator were developed to produce a 150 gauss field within 70 ns. The strap coil was placed at the midplane of the mirror field, where the field is 700 gauss. Based on theoretical estimates and computer simulations a 20 kV potential is expected. Measurement of this potential is derived from the modulation of the current of a monoenergetic electron beam after it passes through the high potential region. The variation in the beam energy allows bunching to occur in transit to the detector.

  4. Mixing and transient interface condensation of a liquid hydrogen tank

    NASA Technical Reports Server (NTRS)

    Lin, C. S.; Hasan, M. M.; Nyland, T. W.

    1993-01-01

    Experiments were conducted to investigate the effect of axial jet-induced mixing on the pressure reduction of a thermally stratified liquid hydrogen tank. The tank was nearly cylindrical, having a volume of about 0.144 cu m with 0.559 m in diameter and 0.711 m length. A mixer/pump unit, which had a jet nozzle outlet of 0.0221 m in diameter was located 0.178 m from the tank bottom and was installed inside the tank to generate the axial jet mixing and tank fluid circulation. Mixing tests began with the tank pressures at which the thermal stratification results in 4.9-6.2 K liquid subcooling. The mixing time and transient vapor condensation rate at the liquid-vapor interface are determined. Two mixing time correlations, based on the thermal equilibrium and pressure equilibrium, are developed and expressed as functions of system and buoyancy parameters. The limited liquid hydrogen data of the present study shows that the modified steady state condensation rate correlation may be used to predict the transient condensation rate in a mixing process if the instantaneous values of jet sub cooling and turbulence intensity at the interface are employed.

  5. Factors affecting the pore space transformation during hydrocarbon generation in source rock (shales): laboratory experiment

    NASA Astrophysics Data System (ADS)

    Giliazetdinova, D. R.; Korost, D. V.

    2014-12-01

    Oil and gas generation is a set of processes which taking place in the interior, the processes can't be observable in nature. In the process of dumping the source rock, organic matter is transformed into a complex of high-molecular compounds - precursors of oil and gas (kerogen). Entering of a source column for specific thermobaric conditions, triggers the formation of low molecular weight hydrocarbon compounds. Generation of sufficient quantities of hydrocarbons leads to the primary fluid migration within the source rock. For the experiment were selected mainly siliceous-carbonate composition rocks from Domanic horizon South-Tatar arch. The main aim of experiment was heating the rocks in the pyrolyzer to temperatures which correspond katagenes stages. For monitoring changes in the morphology of the pore space X-ray microtomography method was used. As a result, when was made a study of the composition of mineral and organic content of the rocks, as well as textural and structural features, have been identified that the majority of the rock samples within the selected collection are identical. However, characteristics such as organic content and texture of rocks are different. Thus, the experiment was divided into two parts: 1) the study of the influence of organic matter content on the morphology of the rock in the process of thermal effects; 2) study the effect of texture on the primary migration processes for the same values of organic matter. Also, an additional experiment was conducted to study the dynamics of changes in the structure of the pore space. At each stage of the experiment morphology of altered rocks characterized by the formation of new pores and channels connecting the primary voids. However, it was noted that the samples with a relatively low content of the organic matter had less changes in pore space morphology, in contrast to rocks with a high organic content. At the second stage of the research also revealed that the conversion of the pore

  6. The stainless steel bulk shielding benchmark experiment at the Frascati Neutron Generator (FNG)

    NASA Astrophysics Data System (ADS)

    Batistoni, P.; Angelone, M.; Martone, M.; Petrizzi, L.; Pillon, M.; Rado, V.; Santamarina, A.; Abidi, I.; Gastaldi, G.; Joyer, P.; Marquette, J. P.; Martini, M.

    1994-09-01

    In the framework of the European Technology Program for NET/ITER, ENEA (Ente Nazionale per le Nuove Tecnologie, l'Energia e l'Ambiente), Frascati and CEA (Commissariat à l'Energie Atomique), Cadarache, are collaborating on a bulk shielding benchmark experiment using the 14 MeV Frascati Neutron Generator (FNG). The aim of the experiment is to obtain accurate experimental data for improving the nuclear database and methods used in the shielding designs, through a rigorous analysis of the results. The experiment consists of the irradiation of a stainless steel block by 14 MeV neutrons. The neutron flux and spectra at different depths, up to 65 cm inside the block, are measured by fission chambers and activation foils characterized by different energy response ranges. The γ-ray dose measurements are performed with ionization chambers and thermo-luminescent dosimeters (TLD). The first results are presented, as well as the comparison with calculations using the cross section library EFF (European Fusion File).

  7. ATTO SECOND ELECTRON BEAMS GENERATION AND CHARACTERIZATION EXPERIMENT AT THE ACCELERATOR TEST FACILITY.

    SciTech Connect

    ZOLOTOREV, M.; ZHOLENTS, A.; WANG, X.J.; BABZIEN, M.; SKARITKA, J.; RAKOWSKY, G.; YAKIMENKO, V.

    2002-02-01

    We are proposing an Atto-second electron beam generation and diagnostics experiment at the Brookhaven Accelerator Test facility (ATF) using 1 {micro}m Inverse Free Electron Laser (IFEL). The proposed experiment will be carried out by an BNL/LBNL collaboration, and it will be installed at the ATF beam line II. The proposed experiment will employ a one-meter long undulator with 1.8 cm period (VISA undulator). The electron beam energy will be 63 MeV with emittance less than 2 mm-mrad and energy spread less than 0.05%. The ATF photocathode injector driving laser will be used for energy modulation by Inverse Free Electron Laser (IFEL). With 10 MW laser peak power, about 2% total energy modulation is expected. The energy modulated electron beam will be further bunched through either a drift space or a three magnet chicane into atto-second electron bunches. The attosecond electron beam bunches will be analyzed using the coherent transition radiation (CTR).

  8. Generation of volcanic ash: a textural study of ash produced in various laboratory experiments

    NASA Astrophysics Data System (ADS)

    Lavallée, Yan; Kueppers, Ulrich; Dingwell, Donald B.

    2010-05-01

    In volcanology, ash is commonly understood as a fragment of a bubble wall that gets disrupted during explosive eruptions. Most volcanic ashes are indeed the product of explosive eruptions, but the true definition is however that of a particle size being inferior to 2 mm. The term does not hold any information about its genesis. During fragmentation, particles of all sizes in various amounts are generated. In nature, fragmentation is a brittle response of the material (whether a rock or magma) caused by changes in 1) strain rate and 2) temperature, and/or 3) chemical composition. Here we used different experimental techniques to produce ash and study their physical characteristics. The effects of strain rate were investigated by deforming volcanic rocks and magma (pure silicate melt and crystal-bearing magma) at different temperatures and stresses in a uniaxial compression apparatus. Failure of pure silicate melts is spontaneous and generates more ash particles than fragmentation of crystal-bearing melts. In the latter, the abundance of generated ash correlates positively with the strain rate. We complemented this investigation with a study of particles generated during rapid decompression of porous rocks, using a fragmentation apparatus. Products of decompression experiments at different initial applied pore pressure show that the amount of ash generated by bubble burst increase with the initial applied pressure and the open porosity. The effects of temperature were investigated by dropping pure silicate melts and crystal-bearing magma at 900 and 1100°C in water at room temperature. Quenching of the material is accompanied by rapid contraction and near instantaneous fragmentation. Pure silicate melts respond more violently to the interaction with water and completely fragmented into small particles, including a variety of ash morphologies and surface textures. Crystal-bearing magmas however fragmented only very partially when in contact with water and produced a

  9. Guiding the Next Generation of Forest FACE Experiments with Lessons from the Past

    NASA Astrophysics Data System (ADS)

    Norby, Richard

    2016-04-01

    respond to future CO2 concentrations. The FACE model-data synthesis (FACE-MDS) project challenged 11 terrestrial ecosystem models with data from the Oak Ridge National Laboratory FACE experiment in Tennessee, USA, and Duke FACE in North Carolina, USA. This exercise was valuable in identifying critical model assumptions and evaluating whether the assumptions were supported by the experimental data, and it provided a framework to evaluate forest processes that occur over much longer time frames than the duration of the experiments. The next generation of forest FACE experiments will greatly expand the breadth of our knowledge base on responses to elevated CO2 by investigating responses of mature forest ecosystems in boreal to tropical biomes over a wide range of climatic and edaphic conditions. Our experience with the FACE-MDS has shown the value in initiating the model-data interaction as an integral part of experimental design. The FACE-MDS framework has led to a set of model-guided, cross-site science questions for new FACE experiments, including responses of mature forests; interactions with temperature, water stress, and phosphorus limitation; and the influence of biodiversity. This sets an exciting research agenda for the next decade.

  10. A Numerical Experiment on the Role of Surface Shear Stress in the Generation of Sound

    NASA Technical Reports Server (NTRS)

    Shariff, Karim; Wang, Meng; Merriam, Marshal (Technical Monitor)

    1996-01-01

    The sound generated due to a localized flow over an infinite flat surface is considered. It is known that the unsteady surface pressure, while appearing in a formal solution to the Lighthill equation, does not constitute a source of sound but rather represents the effect of image quadrupoles. The question of whether a similar surface shear stress term constitutes a true source of dipole sound is less settled. Some have boldly assumed it is a true source while others have argued that, like the surface pressure, it depends on the sound field (via an acoustic boundary layer) and is therefore not a true source. A numerical experiment based on the viscous, compressible Navier-Stokes equations was undertaken to investigate the issue. A small region of a wall was oscillated tangentially. The directly computed sound field was found to to agree with an acoustic analogy based calculation which regards the surface shear as an acoustically compact dipole source of sound.

  11. Recent clinical experience with famciclovir--a "third generation" nucleoside prodrug.

    PubMed

    Chakrabarty, Arun; Tyring, Stephen K; Beutner, Karl; Rauser, Michael

    2004-09-01

    The herpesviruses continue to produce considerable morbidity in man. Once infected with herpes simplex (HSV), the virus remains dormant within the nervous system and may reactivate if provoked by stress, trauma and/or other factors. To date, there is no cure, but antiviral medication can reduce duration and severity of symptoms and prophylaxis can suppress recurrent episodes of disease. The second-generation guanosine nucleosides, acyclovir and penciclovir, are effective inhibitors with low toxicity; both, however, have relatively low oral bioavailability. Subsequently, the orally bioavailable prodrugs valaciclovir and famciclovir have been introduced. These compounds offer high oral bioavailabilty and deliver acyclovir and penciclovir, respectively, to the target cells by means of more convenient dosing schedules. This short review points to recent experience with famciclovir in the management of HSV and varicella-zoster virus. PMID:15535046

  12. Generation of energetic electrons at second harmonic cyclotron resonance in ionospheric HF heating experiments

    NASA Astrophysics Data System (ADS)

    Kuo, S. P.; Rubinraut, M.

    2005-10-01

    The theory of electron acceleration by upper hybrid waves at second harmonic cyclotron resonance is presented. The results show that the meter-scale upper hybrid waves can incorporate the finite Larmour radius effect to make a second harmonic cyclotron resonance interaction effective. The finite Larmour radius effect provides a positive feedback to the interaction, thus the energies of the accelerated electrons increase in time exponentially, rather than linearly as in the case of fundamental cyclotron resonance. Consequently, energetic electrons (having energies larger than 10.7 eV) can be generated even at very low upper hybrid wave intensities. The threshold field for parametric excitation of meter-scale upper hybrid waves by O-mode HF heating wave is shown to be very low. The theory can be a reasonable basis for explaining the enhancement of airglow at 777.4 nm observed in recent low-heating-power experiment at HAARP.

  13. Recording and investigation of the seismic signal generated by hypervelocity impact experiments and numerical models

    NASA Astrophysics Data System (ADS)

    Güldemeister, N.; Moser, D.; Wünnemann, K.; Hoerth, T.; Schäfer, F.

    2013-09-01

    Meteorite impacts can cause environmental consequences, one of which is the generation of ground motions that may exceed the magnitude of the largest earthquakes [1]. Impacts generate shock waves that attenuate with distance until they even tually turn into seismic waves. Thus, meteorite impact may be considered as a source for seismic shaking similar to earthquakes. Seismic signals have been recorded in explosion experiments [2] and in hydrocode models of large impact events such as the Chicxulub crater [3]. To determine how much of the kinetic energy Ekin of the impactoris turned into seismic energy Eseis can be investigated experimentally (by recording the acoustic emission) or by numerical models. The ratio of Eseis/Ekin is the so called seismic efficiency k. The seismic efficiency depends on material properties (porosity) and is usually estimated to range between 10-2 and 10-6 [2,4]. In the framework of the "MEMIN" (multidisciplinary experimental and modeling impact crater research network) project a suite of hypervelocity impact experiments on a decimeter scale have been carried out [5]. We use acoustic emission (AE) technique and pressure gauges in high spatiotemporal Meteorite impacts can cause environmental consequences, one of which is the generation of ground motions that may exceed the magnitude of the largest earthquakes [1]. Impacts generate shock waves that attenuate with distance until they even tually turn into seismic waves. Thus, meteorite impact may be considered as a source for seismic shaking similar to earthquakes. Seismic signals have been recorded in explosion experiments [2] and in hydrocode models of large impact events such as the Chicxulub crater [3]. To determine how much of the kinetic energy Ekin of the impactoris turned into seismic energy Eseis can be investigated experimentally (by recording the acoustic emission) or by numerical models. The ratio of Eseis/Ekin is the so called seismic efficiency k. The seismic efficiency depends

  14. International Space Station United States Orbital Segment Oxygen Generation System On-Orbit Operational Experience

    NASA Technical Reports Server (NTRS)

    Erickson, Robert J.; Howe, John, Jr.; Kulp, Galen W.; VanKeuren, Steven P.

    2008-01-01

    The International Space Station (ISS) United States Orbital Segment (USOS) Oxygen Generation System (OGS) was originally intended to be installed in ISS Node 3. The OGS rack delivery was accelerated, and it was launched to ISS in July of 2006 and installed in the US Laboratory Module. Various modification kits were installed to provide its interfaces, and the OGS was first activated in July of 2007 for 15 hours, In October of 2007 it was again activated for 76 hours with varied production rates and day/night cycling. Operational time in each instance was limited by the quantity of feedwater in a Payload Water Reservoir (PWR) bag. Feedwater will be provided by PWR bag until the USOS Water Recovery System (WRS) is delivered to SS in fall of 2008. This paper will discuss operating experience and characteristics of the OGS, as well as operational issues and their resolution.

  15. Impurity generation during intense lower hybrid heating experiments on the Alcator C tokamak

    NASA Astrophysics Data System (ADS)

    Marmar, E.; Foord, M.; Labombard, B.; Lipschultz, B.; Moreno, J.; Rice, J.; Terry, J.; Lloyd, B.; Porkolab, M.; Schuss, J.; Takase, Y.; Texter, S.; Fiore, C.; Gandy, R.; Granetz, R.; Greenwald, M.; Gwinn, D.; McCool, S.; Pappas, D.; Parker, R. R.; Pribyl, P.; Watterson, R.; Wolfe, S. M.

    1984-05-01

    Experiments are underway on the Alcator C tokamak with over 1 MW of RF power injected into the plasma at a frequency of 4.6 GHz to study both heating and current drive effects. During these studies, impurity generation from limiter structures has been observed. The RF induced impurity influx is a strongly nonlinear function of net injected power. For PRF < 500 kW, only small effects are seen. As PRF approaches 1 MW, however, sharp increases in impurity influxes and Zeff are observed. Three different limiter materials have been used during these studies: molybdenum, graphite, and silicon-carbide coated graphite. In each case, the materials of the limiter structure are seen to dominate the increased impurity influx. In a typical case, with P RF = 1.0 MW, overlinene = 1.3 × 10 14cm-3, and the SiC coated limiters, Zeff is seen to increase from 1.5 before the RF pulse to about 4 during the heating. At the same time, central Te increases from 2000 to 3000 eV and central Ti from 1200 to 1800 eV. Similar effects are seen in both H 2 and D 2 working gas discharges. The contribution to impurity generation of nonthermal electrons, which are produced by the RF, is under investigation. Changes in edge plasma temperature and density, as well as the possibility that the particle transport is affected by the RF, are also being examined. Results of the experiments with the three different limiter materials are compared, and contributions of impurity radiation to the overall power balance are estimated.

  16. Support and control system of the Waste Isolation Pilot Plant gas generation experiment glovebox

    SciTech Connect

    Benjamin, W.W.; Knight, C.J.; Michelbacher, J.A.; Rosenberg, K.E.

    1997-09-01

    A glovebox was designed and fabricated to house test containers loaded with contact handled transuranic (CH-TRU) waste. The test containers were designed to simulate the environmental characteristics of the caverns at the Waste Isolation Pilot Plant (WIPP). The support and control systems used to operate and maintain the Gas Generation Experiment (GGE) include the following: glovebox atmosphere and pressure control, test container support, glovebox operation support, and gas supply and exhaust systems. The glovebox atmosphere and pressure control systems consist of various components used to control both the pressure and quality of the argon atmosphere inside the glovebox. The glovebox pressure is maintained by three separate pressure control systems. The primary pressure control system is designed to maintain the glovebox at a negative pressure with the other two control systems serving as redundant safety backups. The quality of the argon atmosphere is controlled using a purifying bed system that removes oxygen and moisture. Glovebox atmosphere contaminants that are monitored on a continuous or periodic basis include moisture, oxygen, and nitrogen. The gas generation experiment requires the test containers to be filled with brine, leak tested, maintained at a constant temperature, and the gas head space of the test container sampled on a periodic basis. Test container support systems consisting of a brine addition system, leak test system, heating system, and gas sampling system were designed and implemented. A rupture disk system was constructed to provide pressure relief to the test containers. Operational requirements stipulated that test container temperature and pressure be monitored and collected on a continuous basis. A data acquisition system (DAS) was specifically designed to meet these requirements.

  17. Coseismic Damage Generation in Fault Zones by Successive High Strain Rate Loading Experiments

    NASA Astrophysics Data System (ADS)

    Aben, F. M.; Doan, M. L.; Renard, F.; Toussaint, R.; Reuschlé, T.; Gratier, J. P.

    2014-12-01

    Damage zones of active faults control both resistance to rupture and transport properties of the fault. Hence, knowing the rock damage's origin is important to constrain its properties. Here we study experimentally the damage generated by a succession of dynamic loadings, a process mimicking the stress history of a rock sample located next to an active fault. A propagating rupture generates high frequency stress perturbations next to its tip. This dynamic loading creates pervasive damage (pulverization), as multiple fractures initiate and grow simultaneously. Previous single loading experiments have shown a strain rate threshold for pulverization. Here, we focus on conditions below this threshold and the dynamic peak stress to constrain: 1) if there is dynamic fracturing at these conditions and 2) if successive loadings (cumulative seismic events) result in pervasive fracturing, effectively reducing the pulverization threshold to milder conditions. Monzonite samples were dynamically loaded (strain rate > 50 s-1) several times below the dynamic peak strength, using a Split Hopkinson Pressure Bar apparatus. Several quasi-static experiments were conducted as well (strain rate < 10-5-s). Samples loaded up to stresses above the quasi-static uniaxial compressive strength (qsUCS) systematically fragmented or pulverized after four successive loadings. We measured several damage proxies (P-wave velocity, porosity), that show a systematic increase in damage with each load. In addition, micro-computed tomography acquisition on several damage samples revealed the growth of a pervasive fracture network between ensuing loadings. Samples loaded dynamically below the qsUCS failed along one fracture after a variable amount of loadings and damage proxies do not show any a systematic trend. Our conclusions is that milder dynamic loading conditions, below the dynamic peak strength, result in pervasive dynamic fracturing. Also, successive loadings effectively lower the pulverization

  18. High-performance nonequilibrium-plasma magnetohydrodynamic electrical power generator using slightly divergent channel configuration: II. Experiment

    NASA Astrophysics Data System (ADS)

    Murakami, Tomoyuki; Okuno, Yoshihiro

    2008-06-01

    We describe experiments carried out to evaluate a newly developed high-performance nonequilibrium-plasma magnetohydrodynamic (MHD) electrical power generator equipped with a slightly divergent supersonic channel. The slightly divergent generator and a similar-scale highly divergent generator are evaluated in shock-tube experiments. The effects of electrical conductivity control and magnetic flux density control on the generator operation are investigated, and Hall voltage-Hall current characteristics, plasma-fluid behaviour and plasma structures are described. The slightly divergent channel configuration and the application of high- and uniform-density magnetic flux overcome the disadvantages of the generator due to its compactness, and markedly improves its performance. The ratio of isentropic efficiency to enthalpy extraction ratio and the power output density are outstanding compared with previous MHD power generators. The experimental results are supported by the numerically simulated results. This paper is the second part of a duology.

  19. Theory and experiment on particle trapping and manipulation via optothermally generated bubbles

    PubMed Central

    Zhao, Chenglong; Xie, Yuliang; Mao, Zhangming; Zhao, Yanhui; Rufo, Joseph; Yang, Shikuan; Guo, Feng; Mai, John D.

    2014-01-01

    We present a theoretical analysis and experimental demonstration of particle trapping and manipulation around optothermally generated bubbles. We show that a particle located within 500 μm of a surface bubble can be attracted towards a bubble by the drag force resulting from a convective flow. Once the particle comes in contact with the bubble’s surface, a balance between surface tension forces and pressure forces traps the particle on the bubble surface, allowing the particle to move with the bubble without detaching. The proposed mechanism is confirmed by computational fluid dynamics simulations, force calculations, and experiments. Based on this mechanism, we experimentally demonstrated a novel approach for manipulating microparticles via optothermally generated bubbles. Using this approach, randomly distributed microparticles were effectively collected and carried to predefined locations. Single particles were also manipulated along prescribed trajectories. This bubble-based particle trapping and manipulation technique can be useful in applications such as micro assembly, particle concentration, and high-precision particle separation. PMID:24276624

  20. Status of the LBL experiment on femtosecond x-ray generation through 90{degree} Thomson scattering

    SciTech Connect

    Leemans, W.; Chattopadhyay, S.; Conde, M.; Glover, E.; Kim, K.J.; Schoenlein, R.; Shank, C.V.

    1994-06-01

    A status report on the generation of femtosecond X-ray pulses through 90{degrees} Thompson scattering is presented. The experiment involves a relativistic electron beam (tunable from 25--50 MeV) with a bunch length of 10 ps containing 1 {minus}2 nC, and a ultrashort pulse (50--200 fs), high power (4 TW) 0.8 {mu}m Ti:Al{sub 2}O{sub 3} laser system. Both beams are focussed down to about a 50 {mu}m waist size and intersect at 90{degrees}. The laser field acts as an electromagnetic undulator for the relativistic electron beam generating radiation upshifted by 2 {gamma}{sup 2} and a pulse length given by the transit time of the laser beam across the electron beam. For a 50 MeV electron beam we expect 10{sup 5} photons at 0.4 {angstrom} (10% bandwidth) in a cone angle of 6 mrad in a 170 fs pulse.

  1. Helical Striation Pattern Generation and Axial Field Compression in Aluminum Liner Experiments at 1 MA

    NASA Astrophysics Data System (ADS)

    Atoyan, Levon; Byvank, Tom; Greenly, John; Kusse, Bruce; Pikuz, Sergei; Potter, William; Shelkovenko, Tania; Hammer, David

    2015-11-01

    Awe et al. [Phys. Plasmas 21, 235005, 2014] found on the 20 MA Z machine that applying an externally generated axial magnetic field to an imploding liner produces a helical plasma pattern near the surface of the liner. Here we show that this phenomenon is also observed using 10 mm long cylindrical metal liners having 16 mm diameter and 3 to 6 μm wall thickness on the 1 MA, 100-200 ns COBRA pulsed power generator [T. A. Shelkovenko et al., Rev. Sci. Instrum. 77, 10F521, 2006]. The magnetic field in these experiments is created using a 150 μs rise time Helmholtz coil, and the pattern is observed using extreme ultraviolet imaging. Moreover, using B-dot probes we show that there is a 4-8% axial magnetic field compression relative to the initially applied Bz. Using a visible light framing camera, we show that this compression begins before the outside surface of the liner has become a visible light emitting plasma. This research was sponsored by the NNSA SSAP under DOE Coop Agreement DE-NA0001836 and DOE grant DE-NA0001847 as well as by NSF grant PHY-1102471.

  2. Mixing and transient interface condensation of a liquid hydrogen tank

    NASA Technical Reports Server (NTRS)

    Lin, C. S.; Hasan, M. M.; Nyland, T. W.

    1993-01-01

    Experiments were conducted to investigate the effect of axial jet-induced mixing on the pressure reduction of a thermally stratified liquid hydrogen tank. The tank was nearly cylindrical, having a volume of about 0.144 cu m with 0.559 m in diameter and 0.711 m long. A mixer/pump unit, which had a jet nozzle outlet of 0.0221 m in diameter was located 0.178 m from the tank bottom and was installed inside the tank to generate the axial jet mixing and tank fluid circulation. The liquid fill and jet flow rate ranged from 42 to 85 percent (by volume) and 0.409 to 2.43 cu m/hr, respectively. Mixing tests began with the tank pressure ranging from 187.5 to 238.5 kPa at which the thermal stratification results in 4.9 to 6.2 K liquid sub cooling. The mixing time and transient vapor condensation rate at the liquid-vapor interface are determined. Two mixing time correlations, based on the thermal equilibrium and pressure equilibrium, are developed. Both mixing time correlations are expressed as functions of system and buoyancy parameters and compared well with other experimental data. The steady state condensation rate correlation of Sonin et al. based on steam-water data is modified and expressed as a function of jet subcooling. The limited liquid hydrogen data of the present study shows that the modified steady state condensation rate correlation may be used to predict the transient condensation rate in a mixing process if the instantaneous values of jet sub cooling and turbulence intensity at the interface are employed.

  3. Enhanced condensation heat transfer

    NASA Astrophysics Data System (ADS)

    Michel, J. W.; Murphy, R. W.

    1980-07-01

    Work has centered on optimizing the design variables associated with fluted surfaces on vertical tubes and comparing the tube performance with available enhanced tubes either for vertical or horizontal operation. Data with seven fluids including a hydrocarbon, fluorocarbons, and ammonia condensing on up to 30 different tubes were obtained. Data for tubes of different effective lengths (1/2 to 4 ft) and inclination were also obtained. The primary conclusion is that the best fluted tubes can provide an enhancement in condensation coefficient by a factor of approximately 6 over smooth vertical tube performance and a factor of approximately 2 over the best enhanced commercial tubes either operating vertically or horizontally. These data, together with field test data, have formed the basis for designing two prototype condensers, one for the 60 kWe Raft River, Idaho, pilot plant and one for the 500 kWe East Mesa, California, direct contact demonstration plant.

  4. Double cathode experiments using radial foil configurations on the COBRA generator

    NASA Astrophysics Data System (ADS)

    Pang, B. H.; Gorenstein, A. Y.; Kim, J. E.; Gourdain, P.-A.; Hammer, D. A.; Kusse, B. R.

    2010-11-01

    As part of the Laboratory of Plasma Studies at Cornell University, our research group has been investigating the dynamics and the collision of plasma bubbles formed by the explosion of metallic foils. A 100-ns rise time 1MA current runs through an aluminum foil, five micron thick, stretched horizontally onto the anode of the COBRA pulsed power generator. Cathode contacts consist of two hollow stainless pins equally spaced about the center of the foil. The parameters of this experiment include the spacing (3 mm) and inclination of the cathode pins (parallel or at a 45 degree angle). During the explosion, plasma bubbles are formed around each pin. As the bubbles grow and collide, interesting features appear in both experiments. For the parallel cathode configuration, a plasma plume forms above the center between the two bubbles before collision occurs. The plume resembles a twisted helix. For the slanted cathode configuration a plasma sheet forms when the two bubbles collide, and possibly a shock front is formed after the collision. The sheet extends inside a vertical plane just above the foil geometrical center. The electron density of this plasma sheet is approximately 5x10^18 cm-3, and its velocity is below 150 km/s.

  5. A Proof-of-Principle Echo-enabled Harmonic Generation Free Electron Laser Experiment at SLAC

    SciTech Connect

    Pernet, Pierre-Louis

    2010-06-24

    With the advent of X-ray Free Electron Lasers (FELs), new methods have been developed to extend capabilities at short wavelengths beyond Self-Amplified Spontaneous Emission (SASE). In particular, seeding of a FEL allows for temporal control of the radiation pulse and increases the peak brightness by orders of magnitude. Most recently, Gennady Stupakov and colleagues at SLAC proposed a new technique: Echo-Enabled Harmonic Generation (EEHG). Here a laser microbunches the beam in an undulator and the beam is sheared in a chicane. This process is repeated with a second laser, undulator and chicane. The interplay between these allows a seeding of the X-ray laser up to the 100th harmonic of the first laser. After introducing the physics of FELs and the EEHG seeding technique, we describe contributions to the experimental effort. We will present detailed studies of the experiment including the choice of parameters and their optimization, the emittance effect, spontaneous emission in the undulators, the second laser phase effect, and measurements of the jitter between RF stations. Finally, the status and preliminary results of the Echo-7 experiment will be outlined.

  6. Operating experience feedback report -- turbine-generator overspeed protection systems: Commercial power reactors. Volume 11

    SciTech Connect

    Ornstein, H.L.

    1995-04-01

    This report presents the results of the US Nuclear Regulatory Commission`s Office for Analysis and Evaluation of Operational Data (AEOD) review of operating experience of main turbine-generator overspeed and overspeed protection systems. It includes an indepth examination of the turbine overspeed event which occurred on November 9, 1991, at the Salem Unit 2 Nuclear Power Plant. It also provides information concerning actions taken by other utilities and the turbine manufacturers as a result of the Salem overspeed event. AEOD`s study reviewed operating procedures and plant practices. It noted differences between turbine manufacturer designs and recommendations for operations, maintenance, and testing, and also identified significant variations in the manner that individual plants maintain and test their turbine overspeed protection systems. AEOD`s study provides insight into the shortcomings in the design, operation, maintenance, testing, and human factors associated with turbine overspeed protection systems. Operating experience indicates that the frequency of turbine overspeed events is higher than previously thought and that the bases for demonstrating compliance with NRC`s General Design Criterion (GDC) 4, Environmental and dynamic effects design bases, may be nonconservative with respect to the assumed frequency.

  7. Liner velocity, current, and symmetry measurements on the 32 MEGAMP flux compression generator experiment ALT-1

    SciTech Connect

    Anderson, B. G.; Rodriguez, G.; Stokes, J. L.; Tabaka, L. J.; Clark, D. A.

    2001-01-01

    A flux compression generator pulse power system, designed, built, and fielded by a Russian team at the All Russian Scientific Research Institute of Experimental Physics (VNIIEF), was used to successfully drive an aluminum liner to velocities greater than 12 km/sec. The experiment objective was to demonstrate performance of a precision liner implosion at an Atlas current of 30 MA or greater. Diagnostics to measure liner performance were an essential part of the experiment. An experimental team from Los Alamos National Laboratory (LANL) provided a suite of diagnostics to measure liner performance. Three diagnostics were fielded: (1) A velocity interferometer (VISAR) to continuously measure the liner innersurface velocity throughout the entire range of travel, (2) Two Faraday rotation devices to measure liner current during the implosion, and, (3) Sixteen fiber optic impact pins to record liner impact time and provide axial and azimuthal symmetry information. All diagnostics performed very well. Major results are maximum current: 32.3 MA, velocity at impact: greater than 12 km/sec, symmetry: the impact pins indicated that the liner was smooth, solid, and axially symmetric upon arrival at the diagnostic package. The LANL team fabricated, installed, and recorded the three diagnostics presented here. All necessary equipment was brought to the site in Russia. The VNIIEF team fielded other diagnostics to measure machine performance. Results of machine diagnostics are reported in other presentations.

  8. An ITPA joint experiment to study runaway electron generation and suppression

    SciTech Connect

    Granetz, R. S.; Esposito, B.; Kim, J. H.; Koslowski, R.; Lehnen, M.; Martin-Solis, J. R.; Paz-Soldan, C.; Rhee, T.; Wesley, J. C.; Zeng, L.

    2014-07-15

    Recent results from an ITPA joint experiment to study the onset, growth, and decay of relativistic electrons (REs) indicate that loss mechanisms other than collisional damping may play a dominant role in the dynamics of the RE population, even during the quiescent I{sub p} flattop. Understanding the physics of RE growth and mitigation is motivated by the theoretical prediction that disruptions of full-current (15 MA) ITER discharges could generate up to 10 MA of REs with 10–20 MeV energies. The ITPA MHD group is conducting a joint experiment to measure the RE detection threshold conditions on a number of tokamaks under quasi-steady-state conditions in which V{sub loop}, n{sub e}, and REs can be well-diagnosed and compared to collisional theory. Data from DIII-D, C-Mod, FTU, KSTAR, and TEXTOR have been obtained so far, and the consensus to date is that the threshold E-field is significantly higher than predicted by relativistic collisional theory, or conversely, the density required to damp REs is significantly less than predicted, which could have significant implications for RE mitigation on ITER.

  9. An ITPA joint experiment to study runaway electron generation and suppressiona)

    NASA Astrophysics Data System (ADS)

    Granetz, R. S.; Esposito, B.; Kim, J. H.; Koslowski, R.; Lehnen, M.; Martin-Solis, J. R.; Paz-Soldan, C.; Rhee, T.; Wesley, J. C.; Zeng, L.

    2014-07-01

    Recent results from an ITPA joint experiment to study the onset, growth, and decay of relativistic electrons (REs) indicate that loss mechanisms other than collisional damping may play a dominant role in the dynamics of the RE population, even during the quiescent Ip flattop. Understanding the physics of RE growth and mitigation is motivated by the theoretical prediction that disruptions of full-current (15 MA) ITER discharges could generate up to 10 MA of REs with 10-20 MeV energies. The ITPA MHD group is conducting a joint experiment to measure the RE detection threshold conditions on a number of tokamaks under quasi-steady-state conditions in which Vloop, ne, and REs can be well-diagnosed and compared to collisional theory. Data from DIII-D, C-Mod, FTU, KSTAR, and TEXTOR have been obtained so far, and the consensus to date is that the threshold E-field is significantly higher than predicted by relativistic collisional theory, or conversely, the density required to damp REs is significantly less than predicted, which could have significant implications for RE mitigation on ITER.

  10. Weakest students benefit most from a customized educational experience for Generation Y students.

    PubMed

    Nalliah, Romesh P; Allareddy, Veerasathpurush

    2014-01-01

    Most current dental students were born in the 1980s and 1990s and are defined as Generation Y (Gen Y). The authors developed a customized educational experience that brought together some characteristics of Gen Y and the objective of this educational experience was to develop the critical thinking skills of Gen Y students. The objective of the current study is to evaluate outcomes from pre-session and post-session tests. Additionally, we wanted to integrate aspects of team-based learning, self-directed learning and peer-to-peer teaching as a means of reducing the need for intense faculty supervision but maintain positive educational outcomes. Single bitewing x-ray was displayed and informal class discussion was facilitated by a Senior Tutor. A list of questions and concepts that needed to be understood more clearly was made. Student groups self allocated research tasks to members. After conducting research, students presented to class and faculty facilitated discussions aiming to foster critical thinking and identify what information needed to be more thoroughly understood. Pre-session and post-session tests were conducted and compared. Students who scored below 85% in their pre-session test improved their score in the post-session test by a mean of 9.5 points (p = 0.02). Those who scored above 95% in their pre-session test scored less in the post-session test (mean reduction of 6.31 points, p = 0.001). Findings from this study demonstrate that the weakest students in the class (those who scored below 85% correct in the pre-session test) benefitted most from this unique educational experience. PMID:25493212

  11. Weakest students benefit most from a customized educational experience for Generation Y students

    PubMed Central

    Allareddy, Veerasathpurush

    2014-01-01

    Most current dental students were born in the 1980s and 1990s and are defined as Generation Y (Gen Y). The authors developed a customized educational experience that brought together some characteristics of Gen Y and the objective of this educational experience was to develop the critical thinking skills of Gen Y students. The objective of the current study is to evaluate outcomes from pre-session and post-session tests. Additionally, we wanted to integrate aspects of team-based learning, self-directed learning and peer-to-peer teaching as a means of reducing the need for intense faculty supervision but maintain positive educational outcomes. Single bitewing x-ray was displayed and informal class discussion was facilitated by a Senior Tutor. A list of questions and concepts that needed to be understood more clearly was made. Student groups self allocated research tasks to members. After conducting research, students presented to class and faculty facilitated discussions aiming to foster critical thinking and identify what information needed to be more thoroughly understood. Pre-session and post-session tests were conducted and compared. Students who scored below 85% in their pre-session test improved their score in the post-session test by a mean of 9.5 points (p = 0.02). Those who scored above 95% in their pre-session test scored less in the post-session test (mean reduction of 6.31 points, p = 0.001). Findings from this study demonstrate that the weakest students in the class (those who scored below 85% correct in the pre-session test) benefitted most from this unique educational experience. PMID:25493212

  12. Real-time biomimetic Central Pattern Generators in an FPGA for hybrid experiments

    PubMed Central

    Ambroise, Matthieu; Levi, Timothée; Joucla, Sébastien; Yvert, Blaise; Saïghi, Sylvain

    2013-01-01

    This investigation of the leech heartbeat neural network system led to the development of a low resources, real-time, biomimetic digital hardware for use in hybrid experiments. The leech heartbeat neural network is one of the simplest central pattern generators (CPG). In biology, CPG provide the rhythmic bursts of spikes that form the basis for all muscle contraction orders (heartbeat) and locomotion (walking, running, etc.). The leech neural network system was previously investigated and this CPG formalized in the Hodgkin–Huxley neural model (HH), the most complex devised to date. However, the resources required for a neural model are proportional to its complexity. In response to this issue, this article describes a biomimetic implementation of a network of 240 CPGs in an FPGA (Field Programmable Gate Array), using a simple model (Izhikevich) and proposes a new synapse model: activity-dependent depression synapse. The network implementation architecture operates on a single computation core. This digital system works in real-time, requires few resources, and has the same bursting activity behavior as the complex model. The implementation of this CPG was initially validated by comparing it with a simulation of the complex model. Its activity was then matched with pharmacological data from the rat spinal cord activity. This digital system opens the way for future hybrid experiments and represents an important step toward hybridization of biological tissue and artificial neural networks. This CPG network is also likely to be useful for mimicking the locomotion activity of various animals and developing hybrid experiments for neuroprosthesis development. PMID:24319408

  13. Exploring the Basic Principles of Electric Motors and Generators with a Low-Cost Sophomore-Level Experiment

    ERIC Educational Resources Information Center

    Schubert, T. F.; Jacobitz, F. G.; Kim, E. M.

    2009-01-01

    In order to meet changing curricular needs, an electric motor and generator laboratory experience was designed, implemented, and assessed. The experiment is unusual in its early placement in the curriculum and in that it focuses on modeling electric motors, predicting their performance, and measuring efficiency of energy conversion. While…

  14. MOON for a next-generation neutrino-less double-beta decay experiment: Present status and perspective

    SciTech Connect

    Shima, T.; Doe, P.J.; Ejiri, H.; Elliot, S.R.; Engel, J.; Finger, M.; Finger, M.; Fushimi, K.; Gehman, V.M.; Greenfield, M.B.; Hazama, R.; /Hiroshima U. /NIRS, Chiba

    2008-01-01

    The performance of the MOON detector for a next-generation neutrino-less double-beta decay experiment was evaluated by means of the Monte Carlo method. The MOON detector was found to be a feasible solution for the future experiment to search for the Majorana neutrino mass in the range of 100-30 meV.

  15. Parameterization experiments performed via synthetic mass movements prototypes generated by 3D slope stability simulator

    NASA Astrophysics Data System (ADS)

    Colangelo, Antonio C.

    2010-05-01

    each cell in synthetic slope systems performed by relief unity emulator. The central methodological strategy is to locate the potential rupture surfaces (prs), main material discontinuities, like soil-regolith or regolith-rock transitions. Inner these "prs", we would to outline the effective potential rupture surfaces (eprs). This surface is a sub-set of the "prs" that presents safety factor less than unity (f<1), the sub-region in the "prs" equal or deeper than critical depths. When the effective potential rupture surface acquires significant extension with respect the thickness of critical depth and retaining walls, the "slope stability simulator" generates a synthetic mass movement. The overlay material will slide until that a new equilibrium be attained at residual shear strength. These devices generate graphic 3D cinematic sequences of experiments in synthetic slope systems and numerical results about physical and morphological data about scars and deposits. Thus, we have a detailed geotechnical, morphological, topographic and morphometric description of these mass movements prototypes, for deal with effective mass movements found in the real environments.

  16. Interaction effects on number fluctuations in a Bose-Einstein condensate of light.

    PubMed

    van der Wurff, E C I; de Leeuw, A-W; Duine, R A; Stoof, H T C

    2014-09-26

    We investigate the effect of interactions on condensate-number fluctuations in Bose-Einstein condensates. For a contact interaction we variationally obtain the equilibrium probability distribution for the number of particles in the condensate. To facilitate comparison with experiment, we also calculate the zero-time delay autocorrelation function g((2))(0) for different strengths of the interaction. Finally, we focus on the case of a condensate of photons and find good agreement with recent experiments. PMID:25302898

  17. Mechanocaloric and thermomechanical effects in Bose-Einstein-condensed systems

    SciTech Connect

    Marques, G.C.; Bagnato, V.S.; Muniz, S.R.; Spehler, D.

    2004-05-01

    In this paper we extend previous hydrodynamic equations, governing the motion of Bose-Einstein-condensed fluids, to include temperature effects. This allows us to analyze some differences between a normal fluid and a Bose-Einstein-condensed one. We show that, in close analogy with superfluid {sup 4}He, a Bose-Einstein-condensed fluid exhibits the mechanocaloric and thermomechanical effects. In our approach we can explain both effects without using the hypothesis that the Bose-Einstein-condensed fluid has zero entropy. Such ideas could be investigated in existing experiments.

  18. Fidelity Decay in Trapped Bose-Einstein Condensates

    SciTech Connect

    Manfredi, G.; Hervieux, P.-A.

    2008-02-08

    The quantum coherence of a Bose-Einstein condensate is studied using the concept of quantum fidelity (Loschmidt echo). The condensate is confined in an elongated anharmonic trap and subjected to a small random potential such as that created by a laser speckle. Numerical experiments show that the quantum fidelity stays constant until a critical time, after which it drops abruptly over a single trap oscillation period. The critical time depends logarithmically on the number of condensed atoms and on the perturbation amplitude. This behavior may be observable by measuring the interference fringes of two condensates evolving in slightly different potentials.

  19. Evaporation and condensation at a liquid surface. II. Methanol

    NASA Astrophysics Data System (ADS)

    Matsumoto, Mitsuhiro; Yasuoka, Kenji; Kataoka, Yosuke

    1994-11-01

    The rates of evaporation and condensation of methanol under the vapor-liquid equilibrium condition at the temperature of 300 and 350 K are investigated with a molecular dynamics computer simulation. Compared with the argon system (reported in part I), the ratio of self-reflection is similar (˜10%), but the ratio of molecule exchange is several times larger than the argon, which suggests that the conventional assumption of condensation as a unimolecular process completely fails for associating fluids. The resulting total condensation coefficient is 20%-25%, and has a quantitative agreement with a recent experiment. The temperature dependence of the evaporation-condensation behavior is not significant.

  20. Condensation of gauge interacting massless fermions

    SciTech Connect

    Siringo, Fabio

    2004-09-15

    A single massless fermionic field with an Abelian U(1) gauge interaction (electrodynamics of a massless Dirac fermion) is studied by a variational method. Even without the insertion of any extra interaction the vacuum is shown to be unstable towards a particle-antiparticle condensate. The single particle excitations do acquire a mass and behave as massive Fermi particles. An explicit low-energy gap equation has been derived and numerically solved. Some consequences of condensation and mass generation are discussed in the framework of the standard model.

  1. Double-Stranded RNA Resists Condensation

    NASA Astrophysics Data System (ADS)

    Li, Li; Pabit, Suzette A.; Meisburger, Steve P.; Pollack, Lois

    2011-03-01

    Much attention has been focused on DNA condensation because of its fundamental biological importance. The recent discovery of new roles for RNA duplexes demands efficient packaging of double-stranded RNA for therapeutics. Here we report measurements of short DNA and RNA duplexes in the presence of trivalent ions. Under conditions where UV spectroscopy indicates condensation of DNA duplexes into (insoluble) precipitates, RNA duplexes remain soluble. Small angle x-ray scattering results suggest that the differing surface topologies of RNA and DNA may be crucial in generating the attractive forces that result in precipitation.

  2. Improved plant performance through evaporative steam condensing

    SciTech Connect

    Hutton, D.

    1998-07-01

    Combining an open cooling tower and a steam condenser into one common unit is a proven technology with many advantages in power generation application, including reduced first cost of equipment, reduced parasitic energy consumption, simplified design, reduced maintenance, and simplified water treatment, Performance of the steam turbine benefits from the direct approach to wet bulb temperature, and operating flexibility and reliability improve compared to a system with a cooling tower and surface condenser. System comparisons and case histories will be presented to substantiate improved systems economies.

  3. Quantum Phase Diffusion of a Bose-Einstein Condensate

    SciTech Connect

    Lewenstein, M.; You, L.

    1996-10-01

    We discuss the quantum properties of the Bose-Einstein condensate of a dilute gas of atoms in a trap. We show that the phase of the condensate undergoes quantum diffusion which can be detected in far off-resonant light scattering experiments. {copyright} {ital 1996 The American Physical Society.}

  4. A Green Enantioselective Aldol Condensation for the Undergraduate Organic Laboratory

    ERIC Educational Resources Information Center

    Bennett, George D.

    2006-01-01

    A number of laboratory exercises for the organic chemistry curriculum that emphasize enantioselective synthesis of the aldol condensation which involves the proline-catalyzed condensation between acetone and isobutyraldehyde are explored. The experiment illustrates some of the trade-offs involved in green chemistry like the use of acetone in large…

  5. Quantification and kinetics of H2 generation during hydrothermal serpentinisation experiments

    NASA Astrophysics Data System (ADS)

    Castelain, Teddy; Fauguerolles, Colin; Villeneuve, Johan; Pichavant, Michel

    2013-04-01

    H2-rich hydrothermal fluids generated by serpentinisation of mantle rocks at slow-spreading ridges have been revealed by recent studies [1, 2]. Fluxes and the future of the H2 produced by this process are poorly constrained [1, 3]. In this study, we aim to quantitatively evaluate the H2 production fluxes associated with these hydrothermal systems and to document the kinetics of the hydrogen-producing reaction. For this matter, hydrothermal serpentinisation experiments are being undertaken on mixtures composed of a natural peridotite from the Pindus ophiolite and olivine crystals from San Carlos. The experiments are conducted at a temperature of ~ 300° C and a pressure of 450-500 bars in large-volume Dickson-Seyfried bombs for periods of × 1 month. Starting materials are powders between 1 - 100 μm for the peridotites and individual grains ranging from 1 - 2 mm for the San Carlos olivine. They are reacted with a homemade artificial seawater in such proportion that water-rock ratio = 1.8. The reactants are loaded in a modified Ti cell fitted with a semi-permeable Au-Pd membrane simultaneously allowing direct sampling of the hydrothermal fluid and in situ monitoring of the pH2 during the advancement of the reaction. The gas fraction of the fluid sampled is then analyzed by gas chromatography (GC). The pH2 readings show traces of H2 to be present from the second day of experiment. The increase of the pH2 reaches a maximum after ~ 6 days and the pH2 finally stabilizes after ~ 16 days at ~ 12.5 bars, which corresponds to a local fO2 of about NNO-4. The GC measurements, performed after 30, 43, 51 and 65 days, yield respectively, H2 concentrations of 82.4, 89.7, 90.3 and 101 mmol.kg-1 of water, in reasonable agreement with results from previous studies [4-6]. Further experiments are being undertaken in order to: duplicate observations, especially the pH2 readings, more closely link the GC measurements and the in situ pH2 readings, especially during the first 15 days of

  6. Condensation on slippery asymmetric bumps

    NASA Astrophysics Data System (ADS)

    Park, Kyoo-Chul; Kim, Philseok; Grinthal, Alison; He, Neil; Fox, David; Weaver, James C.; Aizenberg, Joanna

    2016-03-01

    Controlling dropwise condensation is fundamental to water-harvesting systems, desalination, thermal power generation, air conditioning, distillation towers, and numerous other applications. For any of these, it is essential to design surfaces that enable droplets to grow rapidly and to be shed as quickly as possible. However, approaches based on microscale, nanoscale or molecular-scale textures suffer from intrinsic trade-offs that make it difficult to optimize both growth and transport at once. Here we present a conceptually different design approach—based on principles derived from Namib desert beetles, cacti, and pitcher plants—that synergistically combines these aspects of condensation and substantially outperforms other synthetic surfaces. Inspired by an unconventional interpretation of the role of the beetle’s bumpy surface geometry in promoting condensation, and using theoretical modelling, we show how to maximize vapour diffusion fluxat the apex of convex millimetric bumps by optimizing the radius of curvature and cross-sectional shape. Integrating this apex geometry with a widening slope, analogous to cactus spines, directly couples facilitated droplet growth with fast directional transport, by creating a free-energy profile that drives the droplet down the slope before its growth rate can decrease. This coupling is further enhanced by a slippery, pitcher-plant-inspired nanocoating that facilitates feedback between coalescence-driven growth and capillary-driven motion on the way down. Bumps that are rationally designed to integrate these mechanisms are able to grow and transport large droplets even against gravity and overcome the effect of an unfavourable temperature gradient. We further observe an unprecedented sixfold-higher exponent of growth rate, faster onset, higher steady-state turnover rate, and a greater volume of water collected compared to other surfaces. We envision that this fundamental understanding and rational design strategy can be

  7. Condensation on slippery asymmetric bumps.

    PubMed

    Park, Kyoo-Chul; Kim, Philseok; Grinthal, Alison; He, Neil; Fox, David; Weaver, James C; Aizenberg, Joanna

    2016-03-01

    Controlling dropwise condensation is fundamental to water-harvesting systems, desalination, thermal power generation, air conditioning, distillation towers, and numerous other applications. For any of these, it is essential to design surfaces that enable droplets to grow rapidly and to be shed as quickly as possible. However, approaches based on microscale, nanoscale or molecular-scale textures suffer from intrinsic trade-offs that make it difficult to optimize both growth and transport at once. Here we present a conceptually different design approach--based on principles derived from Namib desert beetles, cacti, and pitcher plants--that synergistically combines these aspects of condensation and substantially outperforms other synthetic surfaces. Inspired by an unconventional interpretation of the role of the beetle's bumpy surface geometry in promoting condensation, and using theoretical modelling, we show how to maximize vapour diffusion fluxat the apex of convex millimetric bumps by optimizing the radius of curvature and cross-sectional shape. Integrating this apex geometry with a widening slope, analogous to cactus spines, directly couples facilitated droplet growth with fast directional transport, by creating a free-energy profile that drives the droplet down the slope before its growth rate can decrease. This coupling is further enhanced by a slippery, pitcher-plant-inspired nanocoating that facilitates feedback between coalescence-driven growth and capillary-driven motion on the way down. Bumps that are rationally designed to integrate these mechanisms are able to grow and transport large droplets even against gravity and overcome the effect of an unfavourable temperature gradient. We further observe an unprecedented sixfold-higher exponent of growth rate, faster onset, higher steady-state turnover rate, and a greater volume of water collected compared to other surfaces. We envision that this fundamental understanding and rational design strategy can be

  8. Simple Simulations of DNA Condensation

    SciTech Connect

    STEVENS,MARK J.

    2000-07-12

    Molecular dynamics simulations of a simple, bead-spring model of semiflexible polyelectrolytes such as DNA are performed. All charges are explicitly treated. Starting from extended, noncondensed conformations, condensed structures form in the simulations with tetravalent or trivalent counterions. No condensates form or are stable for divalent counterions. The mechanism by which condensates form is described. Briefly, condensation occurs because electrostatic interactions dominate entropy, and the favored Coulombic structure is a charge ordered state. Condensation is a generic phenomena and occurs for a variety of polyelectrolyte parameters. Toroids and rods are the condensate structures. Toroids form preferentially when the molecular stiffness is sufficiently strong.

  9. Comparison of runoff and soil loss generated on two plot sizes during rainfall simulation experiments

    NASA Astrophysics Data System (ADS)

    Kavka, Petr; Dostál, Tomáš; Bauer, Miroslav; Jáchymová, Barbora; Neumann, Martin

    2015-04-01

    square meter) and suspended solids concentration which allows two plots with different dimensions comparison. Our results show influence of the field plot length and a clear increase in the soil loss with increasing plot length. The results suggest that the specific sediment concentration (related to one meter of the plot length) measured at the large plot gauge is about twice the concentration generated by the small plot. A sample for grain size estimation was taken during experiments in last year. The information was used for calculation and comparison of the dragging forces on both plots, the particle size distribution of the eroded particles was also compared to the topsoil texture. The experiments were analysed also with the aim to validate the surface runoff parameters in the mathematical model SMODERP. The input parameters for validation were based on measured: rainfall intensity, time of surface runoff initiation, infiltration and surface runoff discharge, mean velocity and velocity in runoff preferential paths. The research has been supported by the grants No. SGS14/180/OHK1/3T/11 and No. TA02020647.

  10. Detail of Bright Angel stone vault, containing condenser, Hoffman condensation ...

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

    Detail of Bright Angel stone vault, containing condenser, Hoffman condensation pump, Jennings vacuum heating pump, and misc. pipes and valves. - Grand Canyon Village Utilities, Grand Canyon National Park, Grand Canyon Village, Coconino County, AZ

  11. Half-quantum circulation and optical spin Hall effect in a polariton spinor ring condensate

    NASA Astrophysics Data System (ADS)

    Liu, Gangqiang; Snoke, David; Daley, Andrew; Pfeiffer, Loren; West, Kenneth

    2015-05-01

    We have observed half-quantum circulation in a macroscopic polariton spinor condensate in a ring trap. In our experiment, the polaritons come from the strong coupling between photons and electronic excitations (excitons) in quantum wells embedded in a microcavity. The polaritons are repulsively interacting bosons with small effective mass. The ring trap is a combination of a strain-induced harmonic trap and a laser-generated central barrier. By measuring the phase and polarization of the condensate, we find that theres is a phase rotation of π in connection with a polarization rotation of π around a closed path. In addition, the handedness of the circular polarization component, which gives the spin of the polariton, flips from one side of the ring to the other. Such a state is allowed in a ring geometry but is prohibited in a simply-connected geometry. The direction of circulation of the flow around the ring fluctuates randomly between clockwise and counterclockwise; this corresponds to spontaneous breaking of time-reversal symmetry in the system. In contrast, the polarization pattern of the condensate is very stable which is very likely due to the optical spin Hall effect playing a role as the condensate is generated. This work is supported by the National Science Foundation under grants DMR-1104383 and PHY-1148957. The work at Princeton was partially funded by the Gordon and Betty Moore Foundation as well as the National Science Foundation MRSEC Program (DMR-081986).

  12. Inflation from gravitino condensates

    NASA Astrophysics Data System (ADS)

    Mavromatos, Nick E.

    2015-07-01

    We review work on the formation of gravitino condensates via the super-Higgs effect in the early Universe. This is a scenario for both inflating the early universe and breaking local supersymmetry(supergravity), entirely independent of any coupling to external matter. The goldstino mode associated with the breaking of (global) supersymmetry is “eaten” by the gravitino field, which becomes massive (via its own vacuum condensation) and breaks supergravity dynamically. The most natural association of gravitino condensates with inflation proceeds in an indirect way, via a Starobinsky-type inflation, in the massive gravitino phase. This inflationary phase is associated with scalar modes hidden in the higher order curvature corrections of the effective action arising from integrating out massive gravitino degrees of freedom. The scenario is in agreement with Planck data phenomenology in a natural and phenomenologically-relevant range of parameters, namely Grand-Unified-Theory values for the supersymmetry breaking energy scale and dynamically-induced gravitino mass. A hill-top inflation, on the other hand, which could also occur in the model, whereby the role of the inflaton field is played by the gravitino condensate itself, would require significant fine tuning in the inflaton's wave function renormalisation and thus may be discarded on naturalness grounds.

  13. Condensate removal device

    DOEpatents

    Maddox, James W.; Berger, David D.

    1984-01-01

    A condensate removal device is disclosed which incorporates a strainer in unit with an orifice. The strainer is cylindrical with its longitudinal axis transverse to that of the vapor conduit in which it is mounted. The orifice is positioned inside the strainer proximate the end which is remoter from the vapor conduit.

  14. Stability and Heat Transfer Characteristics of Condensing Films

    NASA Astrophysics Data System (ADS)

    Hermanson, J. C.; Pedersen, P. C.; Allen, J. S.; Shear, M. A.; Chen, Z. Q.; Alexandrou, A. N.

    2002-11-01

    . Non-condensing experiments in -1g have employed 50 cSt and 125 cSt silicone oil pumped through the perforated disks at a specified rate by a syringe micropump. The time to droplet break-off and the disturbance wavelengths appear to decrease with increasing pumping rate. The ability to reliably perform multi-point, ultrasonic measurements of the film thickness has been demonstrated. A linear array of eight transducers of 6 mm diameter (with a beam footprint of comparable size) are pulsed with a square-wave signal at a frequency of 5 MHz and a pulse duration of approximately 0.3 s. For thin films (60 m to 2-3 mm in thickness) the layer thickness is determined by frequency analysis, where the received ultrasound pulse is Fourier transformed and the spacing between the peaks in the frequency spectrum is analyzed. For thicker layers (up to at least 1 cm in thickness), time-domain analysis is performed of the received ultrasound pulses to generate directly the layer thickness. A time-trace of the film thickness at a point using a single transducer in the linear array is shown for the case of an unstable (-1g) n-pentane film. The oscillations in film thickness are evidently due to the passage and/or shedding of droplets from the cooled plate surface. The entire transducer array was used to measure the changes in film thickness resulting from the passage of gravity waves generated either by an oscillating wall or the impact of a single droplet on the free surface of a film. The enclosure in both cases was 14 cm square and the transducer spacing was 12 mm. Best results were obtained using as test fluid a mixture of 50% glycerol and 50% water with a fluid layer thickness of 3-5 mm. In both cases the measured wavelengths and wave propagation speeds using the ultrasound technique compared reasonably well with those observed by optical imaging. Additional information can be found in the original extended abstract.

  15. Stability and Heat Transfer Characteristics of Condensing Films

    NASA Technical Reports Server (NTRS)

    Hermanson, J. C.; Pedersen, P. C.; Allen, J. S.; Shear, M. A.; Chen, Z. Q.; Alexandrou, A. N.

    2002-01-01

    . Non-condensing experiments in -1g have employed 50 cSt and 125 cSt silicone oil pumped through the perforated disks at a specified rate by a syringe micropump. The time to droplet break-off and the disturbance wavelengths appear to decrease with increasing pumping rate. The ability to reliably perform multi-point, ultrasonic measurements of the film thickness has been demonstrated. A linear array of eight transducers of 6 mm diameter (with a beam footprint of comparable size) are pulsed with a square-wave signal at a frequency of 5 MHz and a pulse duration of approximately 0.3 s. For thin films (60 m to 2-3 mm in thickness) the layer thickness is determined by frequency analysis, where the received ultrasound pulse is Fourier transformed and the spacing between the peaks in the frequency spectrum is analyzed. For thicker layers (up to at least 1 cm in thickness), time-domain analysis is performed of the received ultrasound pulses to generate directly the layer thickness. A time-trace of the film thickness at a point using a single transducer in the linear array is shown for the case of an unstable (-1g) n-pentane film. The oscillations in film thickness are evidently due to the passage and/or shedding of droplets from the cooled plate surface. The entire transducer array was used to measure the changes in film thickness resulting from the passage of gravity waves generated either by an oscillating wall or the impact of a single droplet on the free surface of a film. The enclosure in both cases was 14 cm square and the transducer spacing was 12 mm. Best results were obtained using as test fluid a mixture of 50% glycerol and 50% water with a fluid layer thickness of 3-5 mm. In both cases the measured wavelengths and wave propagation speeds using the ultrasound technique compared reasonably well with those observed by optical imaging. Additional information can be found in the original extended abstract.

  16. Modeling and experiments on differential pumping in linear plasma generators operating at high gas flows

    SciTech Connect

    Eck, H. J. N. van; Koppers, W. R.; Rooij, G. J. van; Goedheer, W. J.; Cardozo, N. J. Lopes; Kleyn, A. W.; Engeln, R.; Schram, D. C.

    2009-03-15

    The direct simulation Monte Carlo (DSMC) method was used to investigate the efficiency of differential pumping in linear plasma generators operating at high gas flows. Skimmers are used to separate the neutrals from the plasma beam, which is guided from the source to the target by a strong axial magnetic field. In this way, the neutrals are prevented to reach the target region. The neutral flux to the target must be lower than the plasma flux to enable ITER relevant plasma-surface interaction (PSI) studies. It is therefore essential to control the neutral gas dynamics. The DSMC method was used to model the expansion of a hot gas in a low pressure vessel where a small discrepancy in shock position was found between the simulations and a well-established empirical formula. Two stage differential pumping was modeled and applied in the linear plasma devices Pilot-PSI and PLEXIS. In Pilot-PSI a factor of 4.5 pressure reduction for H{sub 2} has been demonstrated. Both simulations and experiments showed that the optimum skimmer position depends on the position of the shock and therefore shifts for different gas parameters. The shape of the skimmer has to be designed such that it has a minimum impact on the shock structure. A too large angle between the skimmer and the forward direction of the gas flow leads to an influence on the expansion structure. A pressure increase in front of the skimmer is formed and the flow of the plasma beam becomes obstructed. It has been shown that a skimmer with an angle around 53 deg. gives the best performance. The use of skimmers is implemented in the design of the large linear plasma generator Magnum-PSI. Here, a three stage differentially pumped vacuum system is used to reach low enough neutral pressures near the target, opening a door to PSI research in the ITER relevant regime.

  17. Bose-Einstein Condensation of Strontium

    SciTech Connect

    Stellmer, Simon; Huang Bo; Grimm, Rudolf; Tey, Meng Khoon; Schreck, Florian

    2009-11-13

    We report on the attainment of Bose-Einstein condensation with ultracold strontium atoms. We use the {sup 84}Sr isotope, which has a low natural abundance but offers excellent scattering properties for evaporative cooling. Accumulation in a metastable state using a magnetic-trap, narrowline cooling, and straightforward evaporative cooling in an optical trap lead to pure condensates containing 1.5x10{sup 5} atoms. This puts {sup 84}Sr in a prime position for future experiments on quantum-degenerate gases involving atomic two-electron systems.

  18. Dynamical spin-density waves in a spin-orbit-coupled Bose-Einstein condensate

    NASA Astrophysics Data System (ADS)

    Li, Yan; Qu, Chunlei; Zhang, Yongsheng; Zhang, Chuanwei

    2015-07-01

    Synthetic spin-orbit (SO) coupling, an important ingredient for quantum simulation of many exotic condensed matter physics, has recently attracted considerable attention. The static and dynamic properties of a SO-coupled Bose-Einstein condensate (BEC) have been extensively studied in both theory and experiment. Here we numerically investigate the generation and propagation of a dynamical spin-density wave (SDW) in a SO-coupled BEC using a fast moving Gaussian-shaped barrier. We find that the SDW wavelength is sensitive to the barrier's velocity while varies slightly with the barrier's peak potential or width. We qualitatively explain the generation of SDW by considering a rectangular barrier in a one-dimensional system. Our results may motivate future experimental and theoretical investigations of rich dynamics in the SO-coupled BEC induced by a moving barrier.

  19. Infrared applications for steam turbine condenser systems

    NASA Astrophysics Data System (ADS)

    Lanius, Mark A.

    2000-03-01

    Infrared inspection of the main steam condensers at the Peach Bottom Atomic Power Station has been utilized successfully in detecting condenser air in-leakage problems. Air in-leakage lowers the condenser's vacuum, thus decreasing the condenser's efficiency. This creates backpressure on the turbine which lowers its efficiency, resulting in fewer megawatts generated. Air in-leakage also creates an increase in off-gas flow which is a radiological concern for both the plant and the public. Inspections are normally performed on the condenser's manway covers and rupture disks prior to an outage during coast down and post outage. The optimum conditions are 100% power and temperature, however, a high radiation field prevents the inspection until reactor power is down to 65% or less. Anomalies are typically indicated by cooling in the effected areas of the air in-leakage. The anomalies are not limited to air in-leakage. Intermittent water out-leakage, due to a heater dump valve cycling, has been detected when visual inspections field nothing.

  20. Simulation Prediction of Transient Dropwise Condensation

    NASA Astrophysics Data System (ADS)

    Macner, Ashley; Daniel, Susan; Steen, Paul

    2014-11-01

    In order to design effective surfaces for large-scale dropwise condensation, an understanding of how surface functionalization affects drop growth and coalescence is needed. The long term technological goal is a set of design conditions to help NASA achieve maximum heat transfer rates of waste heat generated from electronics and habitable environments under microgravity conditions. Prediction of condenser surface heat transfer performance requires accurate simulation and modeling of the evolution of populations of drops in time. At shorter times, drops are primarily isolated and grow mainly by condensation onto the liquid-gas interface. At longer times, drops grow mainly by coalescence with neighbors. Simulation of dropwise condensation on a neutrally wetting surface and comparison with our previous experimental results is reported. A steady-state single drop conduction model is empirically fitted to determine a temperature profile that captures the drop size evolution. The simulation accurately predicts the continuous time evolution of number-density of drops, drop-size distributions, total condensate volume, fractional coverage, and median drop-size for both transient and steady states, all with no free parameters. This work was supported by a NASA Office of the Chief Technologist's Space Technology Research Fellowship.

  1. Laboratory Experiments on the Generation of Perpendicular, Magnetized Collisionless Shocks by a Laser-Ablated Piston

    NASA Astrophysics Data System (ADS)

    Schaeffer, Derek

    2013-10-01

    Collisionless shocks occur ubiquitously in space plasmas and have been extensively studied insitu by spacecraft, though they are inherently limited in their flexibility. We present laboratory experiments utilizing a highly flexible laser geometry at UCLA to study the generation of magnetized, perpendicular collisionless shocks by a super-Alfvénic laser-ablated piston. Experiments were carried out on the LArge Plasma Device (LAPD), which can create a highly reproducible 20 m long by Ø1 m H or He magnetized (<= 2 kG) ambient plasma. The 100 J Raptor laser was used to ablate perpendicular to the background magnetic field a carbon target embedded in the LAPD plasma. Emission spectroscopy revealed a significant spread between laser debris charge states, consistent with 2D hybrid simulations that show fast-moving, highly ionized debris slipping through the ambient plasma, while slower, lower charge states drive a diamagnetic cavity. The cavity grew to several ion gyroradii and lasted around one gyroperiod, large and long enough to act like a piston by allowing laminar fields at the cavity edge to transfer energy from the debris to the background plasma. This is confirmed by spectroscopy, which shows a reduction in debris velocities relative to a non-magnetic case, and Thomson scattering, which shows an increase in electron densities and temperatures in the ambient plasma. An increase in the intensity of the ambient plasma seen by gated imaging also indicates an energetic population of electrons coincident with the cavity edge, while Stark-broadened ambient lines may indicate strong local electric fields. Magnetic flux probes reveal that the cavity launches whistler waves parallel to the background field, as well as a super-Alfvénic magnetosonic wave along the blowoff axis that has a magnetic field compression comparable to the Alfvenic Mach number, consistent with simulations that suggest a weak collisionless shock was formed. Supported by DOE and DTRA.

  2. Analysis of a laboratory experiment on neutron generation by discharges in the open atmosphere

    NASA Astrophysics Data System (ADS)

    Babich, L. P.

    2015-10-01

    A recently reported laboratory experiment with a high-voltage long discharge in the open atmosphere producing neutrons "…up to energies above 10 MeV…" [Agafonov et al., Phys. Rev. Lett. 111, 115003 (2013), 10.1103/PhysRevLett.111.115003] is critically analyzed. Known elementary processes, namely, nuclear synthesis 2H(2H,n )3He and 2H(14N,n )15O , photonuclear, electrodisintegration Anm(e-,n )mprescripts>m n -1 and opposite to the β-decay e-(p+,n ) νe reactions, as well as unconventional mechanisms and the hypothetical increase in the nuclear synthesis cross sections are not capable of accounting for the neutron generation under conditions of the experiment analyzed. In particular, total energy yields of reactions 2H(2H,n )3He and 2H(14N,n )15O are less than the claimed neutron energy above 10 MeV. Trustworthiness of the neutron measurements on the basis of the available study of the C-39 track detectors behavior carried out by Faccini et al. [Eur. Phys. J. C 74, 2894 (2014), 10.1140/epjc/s10052-014-2894-3] in connection with claimed observations of neutron emission in electrolytic cells is discussed. Real-time measurements of x-ray and neutron pulses by Agafonov et al. are commented on using the thorough study of the x-ray emissions by discharges under similar conditions [Kochkin et al., J. Phys. D: Appl. Phys. 45, 425202 (2012), 10.1088/0022-3727/45/42/425202].

  3. Ultra-large-scale Cosmology in Next-generation Experiments with Single Tracers

    NASA Astrophysics Data System (ADS)

    Alonso, David; Bull, Philip; Ferreira, Pedro G.; Maartens, Roy; Santos, Mário G.

    2015-12-01

    Future surveys of large-scale structure will be able to measure perturbations on the scale of the cosmological horizon, and so could potentially probe a number of novel relativistic effects that are negligibly small on sub-horizon scales. These effects leave distinctive signatures in the power spectra of clustering observables and, if measurable, would open a new window on relativistic cosmology. We quantify the size and detectability of the effects for the most relevant future large-scale structure experiments: spectroscopic and photometric galaxy redshift surveys, intensity mapping surveys of neutral hydrogen, and radio continuum surveys. Our forecasts show that next-generation experiments, reaching out to redshifts z≃ 4, will not be able to detect previously undetected general-relativistic effects by using individual tracers of the density field, although the contribution of weak lensing magnification on large scales should be clearly detectable. We also perform a rigorous joint forecast for the detection of primordial non-Gaussianity through the excess power it produces in the clustering of biased tracers on large scales, finding that uncertainties of σ ({f}{{NL}})∼ 1-2 should be achievable. We study the level of degeneracy of these large-scale effects with several tracer-dependent nuisance parameters, quantifying the minimal priors on the latter that are needed for an optimal measurement of the former. Finally, we discuss the systematic effects that must be mitigated to achieve this level of sensitivity, and some alternative approaches that should help to improve the constraints. The computational tools developed to carry out this study, which requires the full-sky computation of the theoretical angular power spectra for {O}(100) redshift bins, as well as realistic models of the luminosity function, are publicly available at http://intensitymapping.physics.ox.ac.uk/codes.html.

  4. Performance study and analysis method for a new-generation MIPAS experiment.

    PubMed

    Carlotti, Massimo; Castelli, Elisa; Dinelli, Bianca Maria; Papandrea, Enzo

    2014-11-17

    This study fits within the ongoing activities aimed at filling the lack of an operational IR limb sounder after the ENVISAT fault. Notably, we report the performance of a possible evolution of the MIPAS experiment. The strategy proposed for the new experiment (that we denote as MIPAS2k) is derived from the PREMIER infrared limb sounder (IRLS) and relies on both 1D array detector technology and reduction of the spectral resolution to achieve dense atmospheric sampling. We define observation parameters and report, as an example, the performance obtained by MIPAS2k when measuring O₃fields. The information load (IL) analysis was exploited to assess the sensitivity of MIPAS2k and to select optimal spectral intervals for retrieval tests on simulated observations of the new experiment. The results of the IL analysis suggest a new approach to the retrieval strategy (denoted as full-2D) in which the unknown parameter is no longer an element of the altitude profile but the constant value taken by the atmospheric quantity within a parcel (denoted as "clove") of the 2D discretization. We demonstrate that the clove homogeneity assumption generates errors that are below the spectral noise of MIPAS2k when an appropriate clove thickness is used. Full-2D retrievals have been carried out on MIPAS2k simulated observations corresponding to a high resolution model atmosphere. We report a test case on O₃ VMR in which the retrieval precision is better than 5% between 20 and 40 km and better than 30% in the upper troposphere-lower stratosphere. We test the ability of MIPAS2k to reconstruct a fine O₃ structure present in the model atmosphere and we show how this structure would have been represented by MIPAS when measuring the same scenario. We have estimated the spatial resolution of MIPAS2k products by means of the perturbation approach that, in simulated retrievals, can be adopted to evaluate the averaging kernel of the retrieval parameters. For O₃ we have found the estimates of

  5. Laboratory Experiments on Wave Emissions Generated by the Variable Viscosity of Fracturing Fluids

    NASA Astrophysics Data System (ADS)

    Dahi Taleghani, A.; Lorenzo, J. M.

    2014-12-01

    Microseismic analysis is recognized as the main method for estimating hydraulic fracture geometry. However, because of limited access to the subsurface and usually high levels of environmental noise it becomes crucial to verify assumed fracture propagation models under more controlled laboratory conditions. Considering the fact that fluid driven fractures may grow under different regimes i.e., toughness-dominated or viscous-dominated, scaling is necessary to reproduce the corresponding fracture growth regime. Scaling is achieved by constraining material deformational parameters, fluid flow rates, and fracturing-fluid viscosity for the appropriate value of the non-dimensional toughness. Hence, we implemented hydraulic fracturing tests on translucent plexiglass samples, at room temperature with contrasting fracturing fluid viscosities. A modest, biaxial loading frame creates relatively low directed principal stresses (< 1000 psi, or less < 1 km overburden pressure). A sealed fluid conduit generates fluid pressures (< 3000 psi) created by a positive displacement pump. We record microseismic events on the upper and lower faces of a thermally annealed, sample block (13 cm x 13 cm x 10 cm) with 3-component, broadband sensors (101-106). Preliminary results indicate that the dominant frequency band of the microseismic events appears similar for both toughness-dominated and viscous-dominated regimes (101-102 Hz). The experiments in both regimes show rippled crack surfaces although in the toughness-dominated regime, 'ripples' are more closely spaced (mm cf. cm). The fracture surfaces show bifurcating, "wish-bone" structures only in the viscous regime.

  6. Trophic and Non-Trophic Interactions in a Biodiversity Experiment Assessed by Next-Generation Sequencing

    PubMed Central

    Tiede, Julia; Wemheuer, Bernd; Traugott, Michael; Daniel, Rolf; Tscharntke, Teja; Ebeling, Anne; Scherber, Christoph

    2016-01-01

    Plant diversity affects species richness and abundance of taxa at higher trophic levels. However, plant diversity effects on omnivores (feeding on multiple trophic levels) and their trophic and non-trophic interactions are not yet studied because appropriate methods were lacking. A promising approach is the DNA-based analysis of gut contents using next generation sequencing (NGS) technologies. Here, we integrate NGS-based analysis into the framework of a biodiversity experiment where plant taxonomic and functional diversity were manipulated to directly assess environmental interactions involving the omnivorous ground beetle Pterostichus melanarius. Beetle regurgitates were used for NGS-based analysis with universal 18S rDNA primers for eukaryotes. We detected a wide range of taxa with the NGS approach in regurgitates, including organisms representing trophic, phoretic, parasitic, and neutral interactions with P. melanarius. Our findings suggest that the frequency of (i) trophic interactions increased with plant diversity and vegetation cover; (ii) intraguild predation increased with vegetation cover, and (iii) neutral interactions with organisms such as fungi and protists increased with vegetation cover. Experimentally manipulated plant diversity likely affects multitrophic interactions involving omnivorous consumers. Our study therefore shows that trophic and non-trophic interactions can be assessed via NGS to address fundamental questions in biodiversity research. PMID:26859146

  7. [Field experiment of F1 generation and superior families selection of Dendrobium officinale].

    PubMed

    Zhang, Xiao-Ling; Si, Jin-Ping; Wu, Ling-Shang; Guo, Ying-Ying; Yu, Jie; Wang, Lin-Hua

    2013-11-01

    Based on randomized block design of experiment, agronomic traits and yields of 14 F1 generations of Dendrobium officinale were determined. The results showed that the differences in agronomic traits and yields among families were significant, and the hybrid vigor was obvious. Families of 6b x 2a, 9 x 66 and 78 x 69 were selected with the remarkable superiority of yields, agronomic traits and product customization. Correlation analysis between agronomic traits and yields showed that plant height, stem diameter, leaf number, blade length and blade width were all significantly correlated with biological yields and economic yields. Among which, stem diameter, leaf number and blade length were the most significant, and an optimal linear regression model could be established. When the number of shoots was fewer than 4.5, both biological yields and economic yields increased with the increasing number of shoots, but it could not much affect yields when the number of shoots was larger than 4.5. Shoots number, stem diameter and leaf index were basic stability when compared biennial traits to annual, which could be used for early selection. PMID:24558865

  8. On the generation of sound by turbulent convection. I - A numerical experiment. [in solar interior

    NASA Technical Reports Server (NTRS)

    Bogdan, Thomas J.; Cattaneo, Fausto; Malagoli, Andrea

    1993-01-01

    Motivated by the problem of the origin of the solar p-modes, we study the generation of acoustic waves by turbulent convection. Our approach uses the results of high-resolution 3D simulations as the experimental basis for our investigation. The numerical experiment describes the evolution of a horizontally periodic layer of vigorously convecting fluid. The sound is measured by a procedure, based on a suitable linearization of the equations of compressible convection that allows the amplitude of the acoustic field to be determined. Through this procedure we identify unambiguously some 400 acoustic modes. The total energy of the acoustic field is found to be a fraction of a percent of the kinetic energy of the convection. The amplitudes of the observed modes depend weakly on (horizontal) wavenumber but strongly on frequency. The line widths of the observed modes typically exceed the natural linewidths of the modes as inferred from linear theory. This broadening appears to be related to the (stochastic) interaction between the modes and the underlying turbulence which causes abrupt, episodic events during which the phase coherence of the modes is lost.

  9. Trophic and Non-Trophic Interactions in a Biodiversity Experiment Assessed by Next-Generation Sequencing.

    PubMed

    Tiede, Julia; Wemheuer, Bernd; Traugott, Michael; Daniel, Rolf; Tscharntke, Teja; Ebeling, Anne; Scherber, Christoph

    2016-01-01

    Plant diversity affects species richness and abundance of taxa at higher trophic levels. However, plant diversity effects on omnivores (feeding on multiple trophic levels) and their trophic and non-trophic interactions are not yet studied because appropriate methods were lacking. A promising approach is the DNA-based analysis of gut contents using next generation sequencing (NGS) technologies. Here, we integrate NGS-based analysis into the framework of a biodiversity experiment where plant taxonomic and functional diversity were manipulated to directly assess environmental interactions involving the omnivorous ground beetle Pterostichus melanarius. Beetle regurgitates were used for NGS-based analysis with universal 18S rDNA primers for eukaryotes. We detected a wide range of taxa with the NGS approach in regurgitates, including organisms representing trophic, phoretic, parasitic, and neutral interactions with P. melanarius. Our findings suggest that the frequency of (i) trophic interactions increased with plant diversity and vegetation cover; (ii) intraguild predation increased with vegetation cover, and (iii) neutral interactions with organisms such as fungi and protists increased with vegetation cover. Experimentally manipulated plant diversity likely affects multitrophic interactions involving omnivorous consumers. Our study therefore shows that trophic and non-trophic interactions can be assessed via NGS to address fundamental questions in biodiversity research. PMID:26859146

  10. Laser Isotope Separation Employing Condensation Repression

    SciTech Connect

    Eerkens, Jeff W.; Miller, William H.

    2004-09-15

    Molecular laser isotope separation (MLIS) techniques using condensation repression (CR) harvesting are reviewed and compared with atomic vapor laser isotope separation (AVLIS), gaseous diffusion (DIF), ultracentrifuges (UCF), and electromagnetic separations (EMS). Two different CR-MLIS or CRISLA (Condensation Repression Isotope Separation by Laser Activation) approaches have been under investigation at the University of Missouri (MU), one involving supersonic super-cooled free jets and dimer formation, and the other subsonic cold-wall condensation. Both employ mixtures of an isotopomer (e.g. {sup i}QF{sub 6}) and a carrier gas, operated at low temperatures and pressures. Present theories of VT relaxation, dimerization, and condensation are found to be unsatisfactory to explain/predict experimental CRISLA results. They were replaced by fundamentally new models that allow ab-initio calculation of isotope enrichments and predictions of condensation parameters for laser-excited and non-excited vapors which are in good agreement with experiment. Because of supersonic speeds, throughputs for free-jet CRISLA are a thousand times higher than cold-wall CRISLA schemes, and thus preferred for large-quantity Uranium enrichments. For small-quantity separations of (radioactive) medical isotopes, the simpler coldwall CRISLA method may be adequate.

  11. The NSF Condensed Matter Physics Program

    NASA Astrophysics Data System (ADS)

    Sokol, Paul

    The Condensed Matter Physics (CMP) program in the NSF Division of Materials Research (DMR) supports experimental, as well as combined experiment and theory projects investigating the fundamental physics behind phenomena exhibited by condensed matter systems. CMP is the largest Individual Investigator Award program in DMR and supports a broad portfolio of research spanning both hard and soft condensed matter. Representative research areas include: 1) phenomena at the nano- to macro-scale including: transport, magnetic, and optical phenomena; classical and quantum phase transitions; localization; electronic, magnetic, and lattice structure or excitations; superconductivity; topological insulators; and nonlinear dynamics. 2) low-temperature physics: quantum fluids and solids; 1D & 2D electron systems. 3) soft condensed matter: partially ordered fluids, granular and colloid physics, liquid crystals, and 4) understanding the fundamental physics of new states of matter as well as the physical behavior of condensed matter under extreme conditions e.g., low temperatures, high pressures, and high magnetic fields. In this talk I will review the current CMP portfolio and discuss future funding trends for the program. I will also describe recent activities in the program aimed at addressing the challenges facing current and future principal investigators.

  12. Why double-stranded RNA resists condensation

    PubMed Central

    Tolokh, Igor S.; Pabit, Suzette A.; Katz, Andrea M.; Chen, Yujie; Drozdetski, Aleksander; Baker, Nathan; Pollack, Lois; Onufriev, Alexey V.

    2014-01-01

    The addition of small amounts of multivalent cations to solutions containing double-stranded DNA leads to inter-DNA attraction and eventual condensation. Surprisingly, the condensation is suppressed in double-stranded RNA, which carries the same negative charge as DNA, but assumes a different double helical form. Here, we combine experiment and atomistic simulations to propose a mechanism that explains the variations in condensation of short (25 base-pairs) nucleic acid (NA) duplexes, from B-like form of homopolymeric DNA, to mixed sequence DNA, to DNA:RNA hybrid, to A-like RNA. Circular dichroism measurements suggest that duplex helical geometry is not the fundamental property that ultimately determines the observed differences in condensation. Instead, these differences are governed by the spatial variation of cobalt hexammine (CoHex) binding to NA. There are two major NA-CoHex binding modes—internal and external—distinguished by the proximity of bound CoHex to the helical axis. We find a significant difference, up to 5-fold, in the fraction of ions bound to the external surfaces of the different NA constructs studied. NA condensation propensity is determined by the fraction of CoHex ions in the external binding mode. PMID:25123663

  13. Condensation and Evaporation of Solar System Materials

    NASA Astrophysics Data System (ADS)

    Davis, A. M.; Richter, F. M.

    2003-12-01

    absence of isotopic fractionation in a volatile element-depleted condensed phase is more a measure of the degree to which the system maintained thermodynamic equilibrium than a diagnostic of whether the path involved condensation or evaporation.The pervasive volatile element depletion of inner solar system planets and the asteroidal parent bodies of most meteorites is a major, but by no means the only reason to consider evaporation and condensation processes in the early history of the solar system. Chondrules appear to have been rapidly heated and then cooled over a period of minutes to hours (see Chapter 1.07). If this occurred in a gas of solar composition under nonequilibrium conditions, chondrules should have partially evaporated and an isotopic fractionation record should remain. The absence of such effects can be used to chonstrain the conditions of chondrule formation (e.g., Alexander et al., 2000; Alexander and Wang, 2001). There is good petrologic, chemical, and isotopic evidence suggesting that certain solar system materials such as the coarse-grained CAIs are likely evaporation residues. For example, the type B CAIs are often found to have correlated enrichments in the heavy isotopes of silicon and magnesium ( Figure 1), and these isotopic fractionations are very much like those of evaporation residues produced in laboratory experiments. Condensation also appears to be a major control of elemental zoning patterns in metal grains in CH chondrites (Meibom et al., 1999, 2001; Campbell et al., 2001; Petaev et al., 2001; Campbell et al., 2002). A more contemporary example is the isotopic and chemical compositions of deep-sea spherules that have been significantly affected by evaporative loss during atmospheric entry ( Davis et al., 1991a; Davis and Brownlee, 1993; Herzog et al., 1994, 1999; Xue et al., 1995; Alexander et al., 2002). (7K)Figure 1. Isotopic mass fractionation effects in CAIs. Most coarse-grained CAIs have enrichments of a few ‰ amu-1 in magnesium

  14. Cytoskeletal Reorganization Drives Mesenchymal Condensation and Regulates Downstream Molecular Signaling

    PubMed Central

    Ray, Poulomi; Chapman, Susan C.

    2015-01-01

    Skeletal condensation occurs when specified mesenchyme cells self-organize over several days to form a distinctive cartilage template. Here, we determine how and when specified mesenchyme cells integrate mechanical and molecular information from their environment, forming cartilage condensations in the pharyngeal arches of chick embryos. By disrupting cytoskeletal reorganization, we demonstrate that dynamic cell shape changes drive condensation and modulate the response of the condensing cells to Fibroblast Growth Factor (FGF), Bone Morphogenetic Protein (BMP) and Transforming Growth Factor beta (TGF-β) signaling pathways. Rho Kinase (ROCK)-driven actomyosin contractions and Myosin II-generated differential cell cortex tension regulate these cell shape changes. Disruption of the condensation process inhibits the differentiation of the mesenchyme cells into chondrocytes, demonstrating that condensation regulates the fate of the mesenchyme cells. We also find that dorsal and ventral condensations undergo distinct cell shape changes. BMP signaling is instructive for dorsal condensation-specific cell shape changes. Moreover, condensations exhibit ventral characteristics in the absence of BMP signaling, suggesting that in the pharyngeal arches ventral morphology is the ground pattern. Overall, this study characterizes the interplay between cytoskeletal dynamics and molecular signaling in a self-organizing system during tissue morphogenesis. PMID:26237312

  15. Experimental Investigation of Flow Condensation in Microgravity

    NASA Technical Reports Server (NTRS)

    Lee, Hyoungsoon; Park, Ilchung; Konishi, Christopher; Mudawar, Issam; May, Rochelle I.; Juergens, Jeffery R.; Wagner, James D.; Hall, Nancy R.; Nahra, Henry K.; Hasan, Mohammed M.; Mackey, Jeffery R.

    2013-01-01

    Future manned missions to Mars are expected to greatly increase the space vehicle's size, weight, and heat dissipation requirements. An effective means to reducing both size and weight is to replace single-phase thermal management systems with two-phase counterparts that capitalize upon both latent and sensible heat of the coolant rather than sensible heat alone. This shift is expected to yield orders of magnitude enhancements in flow boiling and condensation heat transfer coefficients. A major challenge to this shift is a lack of reliable tools for accurate prediction of two-phase pressure drop and heat transfer coefficient in reduced gravity. Developing such tools will require a sophisticated experimental facility to enable investigators to perform both flow boiling and condensation experiments in microgravity in pursuit of reliable databases. This study will discuss the development of the Flow Boiling and Condensation Experiment (FBCE) for the International Space Station (ISS), which was initiated in 2012 in collaboration between Purdue University and NASA Glenn Research Center. This facility was recently tested in parabolic flight to acquire condensation data for FC-72 in microgravity, aided by high-speed video analysis of interfacial structure of the condensation film. The condensation is achieved by rejecting heat to a counter flow of water, and experiments were performed at different mass velocities of FC-72 and water and different FC-72 inlet qualities. It is shown that the film flow varies from smooth-laminar to wavy-laminar and ultimately turbulent with increasing FC-72 mass velocity. The heat transfer coefficient is highest near the inlet of the condensation tube, where the film is thinnest, and decreases monotonically along the tube, except for high FC-72 mass velocities, where the heat transfer coefficient is enhanced downstream. This enhancement is attributed to both turbulence and increased interfacial waviness. One-ge correlations are shown to

  16. Applications in biology and condensed matter physics

    NASA Astrophysics Data System (ADS)

    Faruqi, A. R.

    1991-12-01

    Position-sensitive detectors are a vital research tool in many areas of structural and molecular biology and condensed matter physics. The present review is mainly restricted to structural information obtained by X-ray scattering and diffraction and in DNA sequence analysis using autoradiography. Film has traditionally played the most important role, and for many applications is still the best medium for recording data, but advances in various types of detector technology has made them attractive, and in some cases essential alternatives. The requirements imposed by experiments vary a great deal and can be very demanding in terms of detector performance, e.g. in terms of count rates, particularly for synchrotron radiation, dynamic range, spatial resolution, ability to do time-resolved measurements on a millisecond time scale, differential and integral linearity and resistance to radiation damage. A brief review of detector properties will be presented and how they are matched in different cases with the experimental requirements along with a small selection of recent results and what new developments are needed to cope with the new generation of storage rings now under construction.

  17. Multilayer graphene condenser microphone

    NASA Astrophysics Data System (ADS)

    Todorović, Dejan; Matković, Aleksandar; Milićević, Marijana; Jovanović, Djordje; Gajić, Radoš; Salom, Iva; Spasenović, Marko

    2015-12-01

    Vibrating membranes are the cornerstone of acoustic technology, forming the backbone of modern loudspeakers and microphones. Acoustic performance of a condenser microphone is derived mainly from the membrane’s size, surface mass and achievable static tension. The widely studied and available nickel has been a dominant membrane material for professional microphones for several decades. In this paper we introduce multilayer graphene as a membrane material for condenser microphones. The graphene device outperforms a high end commercial nickel-based microphone over a significant part of the audio spectrum, with a larger than 10 dB enhancement of sensitivity. Our experimental results are supported with numerical simulations, which also show that a 300 layer thick graphene membrane under maximum tension would offer excellent extension of the frequency range, up to 1 MHz.

  18. Gravitational vacuum condensate stars

    PubMed Central

    Mazur, Pawel O.; Mottola, Emil

    2004-01-01

    A new final state of gravitational collapse is proposed. By extending the concept of Bose–Einstein condensation to gravitational systems, a cold, dark, compact object with an interior de Sitter condensate pv = -ρv and an exterior Schwarzschild geometry of arbitrary total mass M is constructed. These regions are separated by a shell with a small but finite proper thickness ℓ of fluid with equation of state p = +ρ, replacing both the Schwarzschild and de Sitter classical horizons. The new solution has no singularities, no event horizons, and a global time. Its entropy is maximized under small fluctuations and is given by the standard hydrodynamic entropy of the thin shell, which is of the order kBℓMc/, instead of the Bekenstein–Hawking entropy formula, SBH = 4πkBGM2/c. Hence, unlike black holes, the new solution is thermodynamically stable and has no information paradox. PMID:15210982

  19. CW laser light condensation.

    PubMed

    Zhurahov, Michael; Bekker, Alexander; Levit, Boris; Weill, Rafi; Fischer, Baruch

    2016-03-21

    We present a first experimental demonstration of classical CW laser light condensation (LC) in the frequency (mode) domain that verifies its prediction (Fischer and Weill, Opt. Express20, 26704 (2012)). LC is based on weighting the modes in a noisy environment in a loss-gain measure compared to an energy (frequency) scale in Bose-Einstein condensation (BEC). It is characterized by a sharp transition from multi- to single-mode oscillation, occurring when the spectral-filtering (loss-trap) has near the lowest-loss mode ("ground-state") a power-law dependence with an exponent smaller than 1. An important meaning of the many-mode LC system stems from its relation to lasing and photon-BEC. PMID:27136845

  20. An event generator for simulations of complex β-decay experiments

    NASA Astrophysics Data System (ADS)

    Jordan, D.; Algora, A.; Tain, J. L.

    2016-08-01

    This article describes a Monte Carlo event generator for the design, optimization and performance characterization of beta decay spectroscopy experimental set-ups. The event generator has been developed within the Geant4 simulation architecture and provides new features and greater flexibility in comparison with the current available decay generator.

  1. Laboratory convection experiments with internal, noncontact, microwave generated heating, applied to Earth's mantle dynamics

    NASA Astrophysics Data System (ADS)

    Limare, Angela; Surducan, Emanoil; di Giuseppe, Erika; Surducan, Vasile; Neamtu, Camelia; Vilella, Kenny; Fourel, Loic; Farnetani, Cinzia; Kaminski, Edouard; Jaupart, Claude

    2014-05-01

    The thermal evolution of terrestrial planets is controlled by secular cooling and internal heating due to the decay of radiogenic isotopes, two processes which are equivalent from the standpoint of convection dynamics. Few studies have been devoted to the intrinsic characteristics of this form of convection, which are dominated by instabilities of a single boundary layer and which involve a non-isentropic interior thermal structure. Laboratory studies of such convection have been plagued by considerable technical difficulties and have been mostly restricted to aqueous solutions with moderate values of the Prandtl number, contrary to planetary mantles. Here, we describe a new laboratory setup to generate internal heating in controlled conditions based on microwave (MW) absorption. The advantages of our technique include, but are not limited to: (1) a volumetric heat source that can be localized or distributed in space, (2) selectively heating part of the volume with time varying intensity and space distribution. Our tank prototype had horizontal dimensions of 30 cm × 30 cm and 5 cm height. A uniform and constant temperature was maintained at the upper boundary by an aluminium heat exchanger and adiabatic conditions were imposed at the tank base. Experimental fluids were hydroxyethylcellulose - water mixtures whose viscosities were varied within a wide range depending on concentration. Experimental Prandtl numbers were set at values larger than 100. Thermochromic Liquid Crystals (TLC) were used to visualize the temperature field, and the velocity field was determined using Particle Image Velocimetry (PIV). The Rayleigh-Roberts number was varied from 105 to 107. We also conducted numerical simulations in 3D cartesian geometry using Stag-3D (Tackley 1993) to reproduce the experimental conditions, including the tank aspect ratio and the temperature dependence of physical properties. We observed that convection is driven by cold descending plumes generated at the upper

  2. Tsunamis generated by 3D deformable landslides in various scenarios: laboratory experiments and numerical modeling

    NASA Astrophysics Data System (ADS)

    McFall, B. C.; Fritz, H. M.; Horrillo, J. J.; Mohammed, F.

    2014-12-01

    Landslide generated tsunamis such as Lituya Bay, Alaska 1958 account for some of highest recorded tsunami runup heights. Source and runup scenarios based on real world events are physically modeled using generalized Froude similarity in the three dimensional NEES tsunami wave basin at Oregon State University. A novel pneumatic landslide tsunami generator (LTG) was deployed to simulate landslides with varying geometry and kinematics. The bathymetric and topographic scenarios tested with the LTG are the basin-wide propagation and runup, fjord, curved headland fjord and a conical island setting representing a landslide off an island or a volcano flank collapse. The LTG consists of a sliding box filled with 1,350 kg of landslide material which is accelerated by pneumatic pistons down slope. Two different landslide materials are used to study the granulometry effects: naturally rounded river gravel and cobble mixtures. Water surface elevations are recorded by an array of resistance wave gauges. The landslide deformation is measured from above and underwater camera recordings. The landslide deposit is measured on the basin floor with a multiple transducer acoustic array (MTA). Landslide surface reconstruction and kinematics are determined with a stereo particle image velocimetry (PIV) system. Wave runup is recorded with resistance wave gauges along the slope and verified with video image processing. The measured landslide and wave parameters are compared between the planar hill slope used in various scenarios and the convex hill slope of the conical island. The energy conversion rates from the landslide motion to the wave train is quantified for the planar and convex hill slopes. The wave runup data on the opposing headland is analyzed and evaluated with wave theories. The measured landslide and tsunami data serve to validate and advance three-dimensional numerical landslide tsunami prediction models. Two 3D Navier-Stokes models were tested, the commercial code FLOW-3D

  3. Experimental investigation of the steam condensation with air and helium

    NASA Astrophysics Data System (ADS)

    Su, Jiqiang; Sun, Zhongning; Fan, Guangming; Ding, Ming

    2013-07-01

    Condensation of steam coming out from the coolant pipe during a loss of coolant accident (LOCA) plays a key role in removing heat from the primary containment of the nuclear reactor. The presence of air and helium reduces the overall heat transfer coefficient substantially. Condensation experiments in the presence of non-condensable gases (e.g. air, helium) were conducted to evaluate the heat removal capacity of a vertical mounted smooth tube. The influences of various parameters, especially the wall subcooling, on the steam condensation heat transfer with non-condensable gases have been obtained for the wall subcooling ranging from 20 to 70°C, total pressure ranging from 2.0×105 Pa to 7.0×105 Pa and air mass fraction ranging from 0.10 to 0.95. The empirical correlations for the heat transfer coefficient, consisting of the mass fraction of the non-condensable gases (air/air helium), total pressure, wall subcooling, and helium mole fraction in non-condensable gases, have been developed based on the experimental results. The relative error of proposed correlations with experimental data is less than 10%. The helium stratification on the condensation has been researched from the distribution of helium fraction and the bulk temperature at different axial positions. It shows that the helium stratification can be ignored when the helium mole fraction in non-condensable gases is less than 35%.

  4. Wave pattern induced by a localized obstacle in the flow of a one-dimensional polariton condensate

    NASA Astrophysics Data System (ADS)

    Larré, P.-É.; Pavloff, N.; Kamchatnov, A. M.

    2012-10-01

    Motivated by recent experiments on generation of wave patterns by a polariton condensate incident on a localized obstacle, we study the characteristics of such flows under the condition that irreversible processes play a crucial role in the system. The dynamics of a nonresonantly pumped polariton condensate in a quasi-one-dimensional quantum wire is modeled by a Gross-Pitaevskii equation with additional phenomenological terms accounting for the dissipation and pumping processes. The response of the condensate flow to an external potential describing a localized obstacle is considered in the weak-perturbation limit and also in the nonlinear regime. The transition from a viscous drag to a regime of wave resistance is identified and studied in detail.

  5. Experience in Developing a Single-Phase Two Winding 5 kW Self-excited Induction Generator for Off-Grid Renewable Energy Based Power Generation

    NASA Astrophysics Data System (ADS)

    Murthy, S. S.; Singh, Bhim; Sandeep, Vuddanti

    2016-06-01

    This paper deals with the design and development of a novel single-phase two winding self-excited squirrel cage induction generator (SEIG) for off-grid renewable energy based power generation. The principles underlying the design process and experience with SPEED design tool are described to design a 5 kW, 50 Hz, 230 V, 4 pole single phase AC generator. All possible configurations to reduce harmonic components of induced e.m.f. are attempted for desired performance and to get an optimum design keeping in view the manufacturing constraints. The development of a prototype based on this design has been completed with the help of an industry. Typical test results on the prototype are presented to demonstrate its performance. Computed results are obtained with a design based computational procedure for performance analysis and a critical comparison is made with test results.

  6. Asymmetric condensed dark matter

    NASA Astrophysics Data System (ADS)

    Aguirre, Anthony; Diez-Tejedor, Alberto

    2016-04-01

    We explore the viability of a boson dark matter candidate with an asymmetry between the number densities of particles and antiparticles. A simple thermal field theory analysis confirms that, under certain general conditions, this component would develop a Bose-Einstein condensate in the early universe that, for appropriate model parameters, could survive the ensuing cosmological evolution until now. The condensation of a dark matter component in equilibrium with the thermal plasma is a relativistic process, hence the amount of matter dictated by the charge asymmetry is complemented by a hot relic density frozen out at the time of decoupling. Contrary to the case of ordinary WIMPs, dark matter particles in a condensate must be lighter than a few tens of eV so that the density from thermal relics is not too large. Big-Bang nucleosynthesis constrains the temperature of decoupling to the scale of the QCD phase transition or above. This requires large dark matter-to-photon ratios and very weak interactions with standard model particles.

  7. Next Generation Ecosystem Experiment: Quantification and prediction of coupled processes in the terrestrial Arctic system

    NASA Astrophysics Data System (ADS)

    Hubbard, S. S.; Hinzman, L. D.; Graham, D. E.; Liang, L.; Norby, R.; Riley, W. J.; Rogers, A.; Rowland, J. C.; Thornton, P. E.; Torn, M. S.; Wilson, C. J.; Wullschleger, S. D.; NGEE Scientific Team

    2011-12-01

    Predicting the evolution of Arctic ecosystems to a changing climate is complicated by the many interactions and feedbacks that occur within and between components of the system. A new DOE Biological and Environmental Research project, called the Next-Generation Ecosystem Experiments (NGEE) is being initiated to address "how does permafrost degradation in a warming Arctic, and the associated changes in landscape evolution, hydrology, soil biogeochemical processes, and plant community succession, affect feedbacks to the climate system?". A multi-disciplinary team will use observations, experiments, and simulations carried out from the pore to the landscape scales to address these questions. We will combine field research (performed around thermokarst features in Alaska on the North Slope and Seward Peninsula), laboratory research using a variety of approaches and techniques, and remote sensing observations to improve modeling capabilities for high-latitude systems. Our research is organized into four interrelated 'Challenges' to quantify: (1) environmental controls on permafrost degradation and its influence on hydrological state, stocks, fluxes and pathways; (2) mechanisms that drive structural and functional responses of the tundra plant community to changing resource availability; (3) controls, mechanisms and rates driving biodegradation of soil organic matter; and (4) the impact of permafrost degradation on ecosystem albedo, energy partitioning and total climate forcing. Coordinated data acquisition will be performed using a variety of commonly-used terrestrial ecosystem characterization approaches as well as novel molecular microbiological, geophysical, isotopic and synchrotron techniques. These datasets will be used in parallel with models to identify the key controls on coupled geomechanical, hydrological, soil biogeochemical, vegetation and land-surface processes, as well as the manifestation of these coupled processes over a broad range of space and time

  8. Experimental evidence needed to demonstrate inter- and trans-generational effects of ancestral experiences in mammals

    PubMed Central

    Dias, Brian G.; Ressler, Kerry J.

    2015-01-01

    Environmental factors routinely influence an organism’s biology. The inheritance or transmission of such influences to descendant generations would be an efficient mode of information transfer across generations. The developmental stage at which a specific environment is encountered by the ancestral generation, and the number of generations over which information about that environment is registered, determines an inter- vs. trans-generational effect of ancestral influence. This commentary will outline the distinction between these influences. While seductive in principle, inter- and trans-generational inheritance in mammals is a hotly debated area of research inquiry. We present constructive criticism of such inheritance, and suggest potential experimental avenues for reconciliation. Finally, epigenetic mechanisms present an avenue for gene regulation that is dynamic. We briefly discuss how such malleability affords the potential for a reversal of any detrimental environmental influences that might have adversely impacted ancestral or descendant generations. PMID:25154497

  9. Simplification of coding of NRU loop experiment software with dimensional generator

    SciTech Connect

    Davis, R. S.

    2006-07-01

    The following are specific topics of this paper: 1.There is much creativity in the manner in which Dimensional Generator can be applied to a specific programming task [2]. This paper tells how Dimensional Generator was applied to a reactor-physics task. 2. In this first practical use, Dimensional Generator itself proved not to need change, but a better user interface was found necessary, essentially because the relevance of Dimensional Generator to reactor physics was initially underestimated. It is briefly described. 3. The use of Dimensional Generator helps make reactor-physics source code somewhat simpler. That is explained here with brief examples from BURFEL-PC and WIMSBURF. 4. Most importantly, with the help of Dimensional Generator, all erroneous physical expressions were automatically detected. The errors are detailed here (in spite of the author's embarrassment) because they show clearly, both in theory and in practice, how Dimensional Generator offers quality enhancement of reactor-physics programming. (authors)

  10. PARISROC, an autonomous front-end ASIC for triggerless acquisition in next generation neutrino experiments

    NASA Astrophysics Data System (ADS)

    Conforti Di Lorenzo, S.; Campagne, J. E.; Drouet, S.; Dulucq, F.; El Berni, M.; Genolini, B.; de La Taille, C.; Martin-Chassard, G.; Seguin Moreau, N.; Wanlin, E.; Xiangbo, Y.

    2012-12-01

    PARISROC (Photomultiplier ARray Integrated in SiGe ReadOut Chip) is a complete readout chip in AustriaMicroSystems (AMS) SiGe 0.35 μm technology designed to read array of 16 Photomultipliers (PMTs). The ASIC is realized in the context of the PMm2 (square meter PhotoMultiplier) project that has proposed a new system of “smart photo-detectors” composed by sensor and read-out electronics dedicated to next generation neutrino experiments. The future water Cherenkov detectors will take place in megaton size water tanks then with a large surface of photo-detection. We propose to segment the large surface in arrays with a single front-end electronics and only the useful data send in surface to be stocked and analyzed. This paper describes the second version of the ASIC and illustrates the chip principle of operation and the main characteristics thank to a series of measurements. It is a 16-channel ASIC with channels that work independently, in triggerless mode and all managed by a common digital part. Then main innovation is that all the channels are handled independently by the digital part so that only channels that have triggered are digitized. Then the data are transferred to the internal memory and sent out in a data driven way. The ASIC allows charge and time measurement. We measured a charge measurement range starting from 160 fC (1 photoelectron-p.e., at PMT gain of 106) to 100 pC (around 600 p.e.) at 1% of linearity; time tagging at 1 ns thanks to a 24-bit counter at 10 MHz and a Time to Digital Converter (TDC) on a 100 ns ramp.

  11. Wild rhesus monkeys generate causal inferences about possible and impossible physical transformations in the absence of experience.

    PubMed

    Hauser, Marc; Spaulding, Bailey

    2006-05-01

    Human infants and adults generate causal inferences about the physical world from observations of single, novel events, thereby violating Hume's thesis that spatiotemporal cooccurrence from prior experience drives causal perception in our species. Is this capacity unique or shared with other animals? We address this question by presenting the results of three experiments on free-ranging rhesus monkeys (Macaca mulatta), focusing specifically on their capacity to generate expectations about the nature of completely unfamiliar physical transformations. By using an expectancy violation looking-time method, each experiment presented subjects with either physically possible or impossible transformations of objects (e.g., a knife, as opposed to a glass of water, appears to cut an apple in half). In both experiments, subjects looked longer when the transformation was impossible than when it was possible. Follow up experiments ruled out that these patterns could be explained by association. These results show that in the absence of training or direct prior experience, rhesus monkeys generate causal inferences from single, novel events, using their knowledge of the physical world to guide such expectations. PMID:16641097

  12. Field-aligned currents and magnetospheric generator in experiments on a laser-produced plasma flowing around a magnetic dipole

    NASA Astrophysics Data System (ADS)

    Shaikhislamov, I. F.; Antonov, V. M.; Zakharov, Yu. P.; Boyarintsev, E. L.; Melekhov, A. V.; Posukh, V. G.; Ponomarenko, A. G.

    2014-07-01

    A laboratory experiment on modeling the magnetospheric generator of the field-aligned currents and the Earth's transpolar potential in the absence of IMF is illustrated. The measurements of the total field-aligned current in the generator shorted mode and the transpolar potential in the circuit disconnection mode made it possible to determine the generator internal resistance. A model that explains the saturation current and internal resistance by the feedback between the field-aligned current and plasma flank motions has been proposed. This feedback is described through the effective resistance, which is proportional to the flow rate and the ratio of the boundary layer to the dimension of the magnetosphere. For the experimental conditions, the calculated generator resistance was in good agreement with the measured value. The estimates for the Earth's magnetosphere indicate that the MHD generator internal resistance in the boundary layer is usually much lower than the reverse integral conductivity of the ionosphere.

  13. Heat transfer from a high temperature condensable mixture. II. Sedimentation of fog condensate

    SciTech Connect

    Condiff, D.W.; Cho, D.H.; Chan, S.H.

    1985-01-01

    A kinematic wave analysis of fog sedimentation is employed to relate growth of a fog condensate deposit layer to radiation generated fog formation rates. The increase of surface radiation absorptivity with deposit layer thickness promotes a feedback mechanism for higher growth rates, which is evaluated in detail.

  14. Loss of feed flow, steam generator tube rupture and steam line break thermohydraulic experiments

    SciTech Connect

    Mendler, O J; Takeuchi, K; Young, M Y

    1986-10-01

    The Westinghouse Model Boiler No. 2 (MB-2) steam generator test model at the Engineering Test Facility in Tampa, Florida, was reinstrumented and modified for performing a series of tests simulating steam generator accident transients. The transients simulated were: loss of feed flow, steam generator tube rupture, and steam line break events. This document presents a description of (1) the model boiler and the associated test facility, (2) the tests performed, and (3) the analyses of the test results.

  15. Why double-stranded RNA resists condensation

    SciTech Connect

    Tolokh, Igor S.; Pabit, Suzette; Katz, Andrea M.; Chen, Yujie; Drozdetski, Aleksander; Baker, Nathan A.; Pollack, Lois; Onufriev, Alexey

    2014-09-15

    The addition of small amounts of multivalent cations to solutions containing double-stranded DNA leads to attraction between the negatively charged helices and eventually to condensation. Surprisingly, this effect is suppressed in double-stranded RNA, which carries the same charge as the DNA, but assumes a different double helical form. However, additional characterization of short (25 base-pairs) nucleic acid (NA) duplex structures by circular dichroism shows that measured differences in condensation are not solely determined by duplex helical geometry. Here we combine experiment, theory, and atomistic simulations to propose a mechanism that connects the observed variations in condensation of short NA duplexes with the spatial variation of cobalt hexammine (CoHex) binding at the NA duplex surface. The atomistic picture that emerged showed that CoHex distributions around the NA reveals two major NA-CoHex binding modes -- internal and external -- distinguished by the proximity of bound CoHex to the helical axis. Decreasing trends in experimentally observed condensation propensity of the four studied NA duplexes (from B-like form of homopolymeric DNA, to mixed sequence DNA, to DNA:RNA hybrid, to A-like RNA) are explained by the progressive decrease of a single quantity: the fraction of CoHex ions in the external binding mode. Thus, while NA condensation depends on a complex interplay between various structural and sequence features, our coupled experimental and theoretical results suggest a new model in which a single parameter connects the NA condensation propensity with geometry and sequence dependence of CoHex binding.

  16. Getting Out, Missing Out, and Surviving: The Social Class Experiences of White, Low-Income, First-Generation College Students

    ERIC Educational Resources Information Center

    Martin, Georgianna LaNelle

    2012-01-01

    The purpose of this study was to understand how White students from low socioeconomic status backgrounds (operationalized as students who are both low income and of the first generation in their family to attend college) experience and navigate social class during college. This was a qualitative research study employing a phenomenological research…

  17. Legacy, legitimacy, and possibility: an exploration of community health worker experience across the generations in Khayelitsha, South Africa.

    PubMed

    Swartz, Alison

    2013-06-01

    In South Africa, the response to HIV and TB epidemics is complex, varied, and contextually defined. "Task-shifting" and a movement toward a decentralized model of care have led to an increased reliance on community health workers (CHWs) providing health care services to residents of impoverished, peri-urban areas. Public health policy tends to present CHWs as a homogeneous group, with little attention paid to the nuances of experience, motivation, and understanding, which distinguish these care workers from one another and from other kinds of health workers. An exploration of the layered meanings of providing community health care services under financially, politically, and socially difficult conditions reveals clear distinctions of experience across the generations. Many older CHWs say that ubuntu, a notion of shared African humanity, is being "killed off" by the younger generation, whereas younger CHWs often describe older women as being "jealous" of the opportunities that this younger generation has for education, training, and employment. The structure of the South African health system, past and present responses to disease epidemics, and the legacy of apartheid's structural violence have amplified these generational differences among CHWs. Using ethnographic data collected from approximately 20 CHWS in a peri-urban settlement in Cape Town, South Africa, I explore how CHWs experience and understand legitimacy in the moral economy of care. A call for closer attention to the experiences of CHWs is critical when designing public health policies for the delivery of health care services in impoverished communities in South Africa. PMID:23804283

  18. First-Generation College Seniors: A Phenomenological Exploration of the Transitional Experience of the Final College Year

    ERIC Educational Resources Information Center

    Overton-Healy, Julia

    2010-01-01

    This study investigated the transitional experience of college seniors who are also first-generation status. This topic merits investigation because there is an increasing interest in various demographics of college students, and because college seniors represent an important retention demographic for American higher education, where the retention…

  19. Perceptions of the College Experience Held by Life Partners of Rural, Nontraditionally-Aged, First-Generation Community College Students

    ERIC Educational Resources Information Center

    Methvin, Jennifer

    2012-01-01

    Rural community colleges serve a large population of nontraditional, first-generation students, many of whom encounter obstacles to degree completion. A life partner who cohabits with a college student impacts the perceptions and actions of that student. However, a gap in research exists about the experiences and perceptions of those life…

  20. Hispanic First-Generation Commuter Students at a Private College Reflect on Their Experience through the First Year

    ERIC Educational Resources Information Center

    Lurvey, Phyllis C.

    2011-01-01

    A volunteer sample of 16 Hispanic first-generation commuter college students, 9 women and 7 men, 18-30 years of age, attending a private college in the Northeast, were interviewed about their first-year college experience, with an emphasis on issues related to cultural capital and habitus. Five aspects of cultural capital were of interest:…

  1. Conducting Multi-Generational Qualitative Research in Education: An Experiment in Grounded Theory. Black Studies and Critical Thinking. Volume 5

    ERIC Educational Resources Information Center

    Collins, Donald R.

    2011-01-01

    This book outlines a methodology for viewing multiple generations of African Americans, specifically those who were called or called themselves Negro, Colored, Black, or African American (NCBAA). Within this framework, African Americans of varying ages describe their lives and educational experiences, allowing researchers to address a variety of…

  2. Mexican American First-Generation/Low-Income Students: A Rural Community College, TRiO Student Support Services Experience

    ERIC Educational Resources Information Center

    O'Meara, Daniel J.

    2012-01-01

    This study is an ethnographic inquiry into the beliefs and perceptions of first-generation/low-income Mexican American students in a rural community college located near the U.S.-Mexico border. It explored their experiences as TRiO Student Support Services participants. TRiO Student Support Services plays an increasingly vital role helping…

  3. Race-Gender Experiences and Schooling: Second-Generation Dominican, West Indian, and Haitian Youth in New York City.

    ERIC Educational Resources Information Center

    Lopez, Nancy

    2002-01-01

    Examined the race-gender gap in education among second-generation Caribbean American young adults (Dominicans, Haitians, and anglophone West Indians), using life history interviews, focus groups, and participant observation to investigate how their cumulative race-gender experiences influenced their outlooks toward schooling. Overall, women…

  4. Relationship between Academic Resilience and College Success: Cross-National Experiences of Low-Income/First-Generation Students

    ERIC Educational Resources Information Center

    Mbindyo, Margaret N.

    2011-01-01

    The present study examines the relationship between academic resilience (defined as the ability to effectively deal with setbacks, stress, or pressure in an academic setting) and the experiences of US students served by TRIO intervention programs (federally funded programs) that serve low-income/first-generation students. Based on a sample of 106,…

  5. Experiences of Latina First Generation College Students: Exploring Resources Supporting the Balancing of Academic Pursuits and Family Life

    ERIC Educational Resources Information Center

    Corona-Ordonez, Hercilia B.

    2013-01-01

    This study used a qualitative interview approach and thematic analysis (Braune and Clark, 2006) to interview first generation college student Latinas, exploring their experiences with higher education, their navigation/negotiation of resources for academic success and for wellness of self and family, and barriers they face as they attempt to both…

  6. "Desafios y Bendiciones": A Multiperspective Examination of the Educational Experiences and Coping Responses of First-Generation College Latina Students

    ERIC Educational Resources Information Center

    Gloria, Alberta M.; Castellanos, Jeanett

    2012-01-01

    Taking a multiperspective approach, seven Latina students, two student services personnel, and one mental health service provider are interviewed to gain different stakeholder perspectives regarding Latina first-generation college educational and coping experiences. Familial involvement and connections with family, peers, and university personnel…

  7. First-Generation Latino Males in Latino Fraternities at a Predominately White Institution: Psychological, Social, and Cultural College Experiences

    ERIC Educational Resources Information Center

    Sanchez, Sheila Marie

    2011-01-01

    This research study explores the first-generation undergraduate Latino male student experience at a Predominantly White Institution (PWI) affiliated within Latino Greek fraternities. The Psychosociocultural (PSC) model (Gloria & Rodriguez, 2000; Pope & Reynolds, 2000) that is used highlights the psychological, social and cultural contributing…

  8. Effect of spontaneous condensation on condensation heat transfer in the presence of non-condensable gases

    SciTech Connect

    Karl, J.; Hein, D.

    1999-07-01

    The presence of non condensable gases like nitrogen or air reduces the condensation heat transfer during condensation of binary steam mixtures. The non condensable gas accumulates in the vapor phase boundary layer and causes a high heat transfer resistance. Especially with high pressures and low water temperatures spontaneous condensation reduces heat transfer additionally. Fog forms within the steam-nitrogen boundary layer and the steam condenses on the water droplets of the fog layer. The convective mass transfer to the cooling water interface diminishes. Raman spectroscopy and film theory are used to quantify this effect locally. The calculation of overall condensation rates in large steam nitrogen systems requires to use three dimensional CFD codes. The paper presents equations to predict fog formation in the boundary layer which can be implemented in CFD codes.

  9. Precursor Proof-of-Concept Experiments for Various Categories of High-Frequency Gravitational Wave (HFGW) Generators

    NASA Astrophysics Data System (ADS)

    Baker, Robert M. L.

    2004-02-01

    High-Frequency Gravitational Wave (HFGW) generators are separated into three general categories. Precursor, component-validation, laboratory experiments for each category except, possibly, the third are identified in general terms. The categories are: (1) The electromechanical category includes micro- and nano-element, piezoelectric crystal, and multi-dielectric film HFGW generators. (2) The high-temperature superconductor category includes gasers, impressed magnetic fields, and transformation of electromagnetic radiation into gravitational waves (Gertsenshtein effect) HFGW generators. (3)The laser/plasma category includes laser-energized mirrors, synchrotron light, nuclear fusion, plasma toroid, and nonlinear optical-acoustical, molecular-level HFGW generators. A perusal of HFGW literature reveals that since the 1960s many authors have contributed designs of mechanisms and devices that relate to the terrestrial generation of gravitational waves. Only in the last few years, however, have any researchers demonstrated that their proposed devices were practical HFGW generators, capable of producing kilowatts of power, that were operational in a laboratory setting. These recent devices make use of new technology and generate high-frequency (GHz and above) gravitational waves using non-gravitational forces. Most of the generators considered in this paper have been recently discussed at the May, 2003, Gravitational Wave Conference at The MITRE Corporation, McLean, VA, which was the very first International Conference dedicated to HFGW and attracted twenty-five research papers from nine countries. Although no detailed experimental tasks are discussed, experimental test objectives in the form of a roadmap are proposed for each category.

  10. Examining the Experiences of Three Generations of Teacher Researchers through Collaborative Science Teacher Inquiry

    ERIC Educational Resources Information Center

    Capobianco, Brenda M.; Lincoln, Susan; Canuel-Browne, Donna; Trimarchi, Ruth

    2006-01-01

    The purpose of this article is to examine the teacher research movement from the perspective of three generations of teacher researchers within the context of a unique collaborative science teacher action research group. The question that guided the study was the following: In what ways do three generations of science teachers perceive their…

  11. Exploring the Experiences of Successful First-Generation Community College Students in Florida: A Qualitative Study

    ERIC Educational Resources Information Center

    Patron, Iliana M.

    2012-01-01

    As jobs become more competitive and demanding of specialized training, the presence of first-generation college students will continue to be a growing reality. However, unless the needs of first-generation students are addressed by educational institutions, the motivation experienced by those students to attend college will be short-lived. Even…

  12. Generational Differences and Participant Experiences in Leadership Development: A Phenomenological Study

    ERIC Educational Resources Information Center

    Remedies, Suzanne E.

    2012-01-01

    This qualitative phenomenological study examines generational cohort perceptions as they apply to civilian leadership training within the DOD. Zenger, Ulrich and Smallwood (2000) describe that a new approach for developing future leaders is necessary. Identifying whether generational perceptions of ELDP members positively or negatively impact DOD…

  13. "Limbo" through the Looking Glass: Adding the Voice of Family to the First Generation College Experience

    ERIC Educational Resources Information Center

    Daniel, Malinda Nichols

    2012-01-01

    In 2009 of the 9,793 undergraduates attending the University of Wyoming during the fall semester, 3,453 of them were first generation college students. The cultural assimilation often associated with college for first generation college students is often experienced by not only the student, but also the family left at home. This research serves as…

  14. Spin selective filtering of polariton condensate flow

    SciTech Connect

    Gao, T.; Antón, C.; Martín, M. D.; Liew, T. C. H.; Hatzopoulos, Z.; Viña, L.; Eldridge, P. S.; Savvidis, P. G.

    2015-07-06

    Spin-selective spatial filtering of propagating polariton condensates, using a controllable spin-dependent gating barrier, in a one-dimensional semiconductor microcavity ridge waveguide is reported. A nonresonant laser beam provides the source of propagating polaritons, while a second circularly polarized weak beam imprints a spin dependent potential barrier, which gates the polariton flow and generates polariton spin currents. A complete spin-based control over the blocked and transmitted polaritons is obtained by varying the gate polarization.

  15. Gravitational Condensate Stars

    NASA Astrophysics Data System (ADS)

    Mazur, P.; Mottola, E.

    The issue of the final state of the gravitational collapse will be addressed. Ishall present physical arguments to the effect that the remnant of the gravitationalcollapse of super-massive stars is a cold and dark super-dense object which isthermodynamically and dynamically stable: a Gravitational Condensate Star orQuasi Black Hole (QBH). A QBH is characterized by a huge, but not an infinite,surface redshift. This surface redshift depends universally on the total mass of aQBH and the proper thickness of a thin shell of an exotic matter described bythe Zel'dovich equation of state p = c2 . The velocity of sound in a thin shell isequal to the velocity of light. Hence, this thin shell replaces the event horizon of amathematical black hole ( = 0). Inside a thin shell the zero entropy gravitationalcondensate characterized by the cosmological equation of state p = -c2 resides.A QBH is described by a new static and spherically symmetric solution of Ein-stein's equations supplemented with the proper boundary conditions based on mi-crophysics considerations. The new solution has no singularities and no eventhorizons. Its entropy is maximized under small fluctuations and is given by thestandard hydrodynamic entropy of the thin shell which is proportional to the to-tal mass instead of the Bekenstein-Hawking entropy which is proportional to thesquare of the total mass. This resolves the paradox of an excessively high en-tropy of black holes as compared to their progenitors. The formation of such acold gravitational condensate stellar remnant very likely would require a violentcollapse process with an explosive output of energy. Some observational conse-quences of the formation of gravitational condensate stars will be described.

  16. French Regulatory practice and experience feedback on steam generator tube integrity

    SciTech Connect

    Sandon, G.

    1997-02-01

    This paper summarizes the way the French Safety Authority applies regulatory rules and practices to the problem of steam generator tube cracking in French PWR reactors. There are 54 reactors providing 80% of French electrical consumption. The Safety Authority closely monitors the performance of tubes in steam generators, and requires application of a program which deals with problems prior to the actual development of leakage. The actual rules regarding such performance are flexible, responding to the overall performance of operating steam generators. In addition there is an inservice inspection service to examine tubes during shutdown, and to monitor steam generators for leakage during operation, with guidelines for when generators must be pulled off line.

  17. Investigation of condensed and early stage gas phase hypergolic reactions

    NASA Astrophysics Data System (ADS)

    Dennis, Jacob Daniel

    Traditional hypergolic propellant combinations, such as those used on the space shuttle orbital maneuvering system first flown in 1981, feature hydrazine based fuels and nitrogen tetroxide (NTO) based oxidizers. Despite the long history of hypergolic propellant implementation, the processes that govern hypergolic ignition are not well understood. In order to achieve ignition, condensed phase fuel and oxidizer must undergo simultaneous physical mixing and chemical reaction. This process generates heat, intermediate condensed phase species, and gas phase species, which then may continue to react and generate more heat until ignition is achieved. The process is not well understood because condensed and gas phase reactions occur rapidly, typically in less than 200 μs, on much faster timescales than traditional diagnostic methods can observe. A detailed understanding of even the gas phase chemistry is lacking, but is critical for model development. Initial research has provided confidence that a study of condensed phase hypergolic reactions is useful and possible. Results obtained using an impinging jet apparatus have shown a critical residence time of 0.3 ms is required for the reaction between monomethylhydrazine (MMH) and red fuming nitric acid (RFNA, ~85% HNO3 + 15% N2O4) to achieve conditions favorable for ignition. This critical residence time spans the time required for liquid phase reactions to occur at the fuel/oxidizer interface and can give some insight into the reaction rates for this propellant combination. Experiments performed in a forced mixing constant volume reactor have demonstrated that the chamber pressurization rate for MMH/RFNA can be significantly reduced by diluting the MMH with deionized water. This result indicates that propellant dilution can slow the chemical reaction rates to occur over observable time scales. The research described in this document consists of two efforts that contribute knowledge to the propulsion community regarding the

  18. Expansion in condensates

    SciTech Connect

    Chakrabarti, J.; Sajjad Zahir, M.

    1985-03-01

    We show that the product of local current operators in quantum chromodynamics (QCD), when expanded in terms of condensates, such as psi-barpsi, G/sup a//sub munu/ G/sup a//sub munu/, psi-barGAMMA psipsi-barGAMMApsi, f/sub a/bcG/sup a//sub munu/G/sup b//sub nualpha/ x G/sup c//sub alphamu/, etc., yields a series in Planck's constant. This, however, provides no hint that the higher terms in such an expansion may be less significant.

  19. Condensation Processes in Astrophysical Environments

    NASA Technical Reports Server (NTRS)

    Nuth, Joseph A., III; Rietmeijer, Frans J. M.; Hill, Hugh G. M.

    2002-01-01

    Astrophysical systems present an intriguing set of challenges for laboratory chemists. Chemistry occurs in regions considered an excellent vacuum by laboratory standards and at temperatures that would vaporize laboratory equipment. Outflows around Asymptotic Giant Branch (AGB) stars have timescales ranging from seconds to weeks depending on the distance of the region of interest from the star and, on the way significant changes in the state variables are defined. The atmospheres in normal stars may only change significantly on several billion-year timescales. Most laboratory experiments carried out to understand astrophysical processes are not done at conditions that perfectly match the natural suite of state variables or timescales appropriate for natural conditions. Experimenters must make use of simple analog experiments that place limits on the behavior of natural systems, often extrapolating to lower-pressure and/or higher-temperature environments. Nevertheless, we argue that well-conceived experiments will often provide insights into astrophysical processes that are impossible to obtain through models or observations. This is especially true for complex chemical phenomena such as the formation and metamorphism of refractory grains under a range of astrophysical conditions. Data obtained in our laboratory has been surprising in numerous ways, ranging from the composition of the condensates to the thermal evolution of their spectral properties. None of this information could have been predicted from first principals and would not have been credible even if it had.

  20. CLAS+FROST: new generation of photoproduction experiments at Jefferson Lab

    SciTech Connect

    Eugene Pasyuk

    2009-12-01

    A large part of the experimental program in Hall B of the Jefferson Lab is dedicated to baryon spectroscopy. Photoproduction experiments are essential part of this program. CEBAF Large Acceptance Spectrometer (CLAS) and availability of circularly and linearly polarized tagged photon beams provide unique conditions for this type of experiments. Recent addition of the Frozen Spin Target (FROST) gives a remarkable opportunity to measure double and triple polarization observables for different pseudo-scalar meson photoproduction processes. For the first time, a complete or nearly complete experiment becomes possible and will allow model independent extraction of the reaction amplitude. An overview of the experiment and its current status is presented.

  1. Development and application of an analysis methodology for interpreting ambiguous historical pressure data in the WIPP gas-generation experiments.

    SciTech Connect

    Felicione, F. S.

    2006-01-23

    The potential for generation of gases in transuranic (TRU) waste by microbial activity, chemical interactions, corrosion, and radiolysis was addressed in the Argonne National Laboratory-West (ANL-West) Gas-Generation Experiments (GGE). Data was collected over several years by simulating the conditions in the Waste Isolation Pilot Plant (WIPP) after the eventual intrusion of brine into the repository. Fourteen test containers with various actual TRU waste immersed in representative brine were inoculated with WIPP-relevant microbes, pressurized with inert gases, and kept in an inert-atmosphere environment for several years to provide estimates of the gas-generation rates that will be used in computer models for future WIPP Performance Assessments. Modest temperature variations occurred during the long-term ANL-West experiments. Although the experiment temperatures always remained well within the experiment specifications, the small temperature variation was observed to affect the test container pressure far more than had been anticipated. In fact, the pressure variations were so large, and seemingly erratic, that it was impossible to discern whether the data was even valid and whether the long-term pressure trend was increasing, decreasing, or constant. The result was that no useful estimates of gas-generation rates could be deduced from the pressure data. Several initial attempts were made to quantify the pressure fluctuations by relating these to the measured temperature variation, but none was successful. The work reported here carefully analyzed the pressure measurements to determine if these were valid or erroneous data. It was found that a thorough consideration of the physical phenomena that were occurring can, in conjunction with suitable gas laws, account quite accurately for the pressure changes that were observed. Failure of the earlier attempts to validate the data was traced to the omission of several phenomena, the most important being the variation in

  2. Convection, evaporation, and condensation of binary fluids in confined geometries

    NASA Astrophysics Data System (ADS)

    Grigoriev, Roman; Qin, Tongran; Li, Yaofa; Chan, Benjamin; Yoda, Minami

    2011-11-01

    Phase change has a major effect on convection in liquid layers with a free surface. Significant latent heat generated at the free surface as a result of phase change can dramatically alter the interfacial temperature, inducing thermocapillary stresses. For binary fluids, differential evaporation leads to a variation in the concentration, and hence, induces solutocapillary stresses. This talk describes numerical and experimental studies of convection in alcohol-water mixtures due to a horizontal temperature gradient in the presence of phase change. Evaporation and condensation is known to be a notoriously difficult problem to model due to a poorly defined vapor transport problem which is strongly influenced by the presence/absence and flows of non-condensable gases (e.g., air). This issue is addressed by using a sealed cuvette heated at one end and cooled at the other. Both numerics and experiments show that, by adding or removing air from the cuvette, the direction of flow in a liquid layer covering the bottom of the cell can be reversed by emphasizing either thermocapillary or solutocapillary stresses. Supported by ONR.

  3. Gravitational vacuum condensate stars.

    PubMed

    Mazur, Pawel O; Mottola, Emil

    2004-06-29

    A new final state of gravitational collapse is proposed. By extending the concept of Bose-Einstein condensation to gravitational systems, a cold, dark, compact object with an interior de Sitter condensate p(v) = -rho(v) and an exterior Schwarzschild geometry of arbitrary total mass M is constructed. These regions are separated by a shell with a small but finite proper thickness l of fluid with equation of state p = +rho, replacing both the Schwarzschild and de Sitter classical horizons. The new solution has no singularities, no event horizons, and a global time. Its entropy is maximized under small fluctuations and is given by the standard hydrodynamic entropy of the thin shell, which is of the order k(B)lMc/Planck's over 2 pi, instead of the Bekenstein-Hawking entropy formula, S(BH) = 4 pi k(B)GM(2)/Planck's over 2 pi c. Hence, unlike black holes, the new solution is thermodynamically stable and has no information paradox. PMID:15210982

  4. Cosmic curvature and condensation

    NASA Technical Reports Server (NTRS)

    Harwit, Martin

    1992-01-01

    It is shown that the universe may consist of a patchwork of domains with different Riemann curvature constants k = 0, +/-1. Features of a phase transition in which flat space breaks up in a transition 2k0 - k(-) + k(+) with initial scale factors R(-) = R(+) are postulated and explored. It is shown that such a transition is energetically permitted, has the equivalent of a Curie temperature, and can lead in a natural way to the formation of voids and galaxies. It is predicted that, if the ambient universe on average is well fitted by a purely k(-) space, with only occasional domains of k(+) containing galaxies, a density parameter of (A(z sub c + 1)) super -1 should be expected, where z sub c represents the redshift of the earliest objects to have condensed, and A takes on values ranging from about 5 to 3. Present observations of quasars would suggest a density of about 0.03 or 0.05, respectively, but it could be lower if earlier condensation took place.

  5. A multi-field approach to DNA condensation

    NASA Astrophysics Data System (ADS)

    Ran, Shi-Yong; Jia, Jun-Li

    2015-12-01

    DNA condensation is an important process in many fields including life sciences, polymer physics, and applied technology. In the nucleus, DNA is condensed into chromosomes. In polymer physics, DNA is treated as a semi-flexible molecule and a polyelectrolyte. Many agents, including multi-valent cations, surfactants, and neutral poor solvents, can cause DNA condensation, also referred to as coil-globule transition. Moreover, DNA condensation has been used for extraction and gene delivery in applied technology. Many physical theories have been presented to elucidate the mechanism underlying DNA condensation, including the counterion correlation theory, the electrostatic zipper theory, and the hydration force theory. Recently several single-molecule studies have focused on DNA condensation, shedding new light on old concepts. In this document, the multi-field concepts and theories related to DNA condensation are introduced and clarified as well as the advances and considerations of single-molecule DNA condensation experiments are introduced. Project supported by the National Natural Science Foundation of China (Grant Nos. 21204065 and 20934004) and the Natural Science Foundation of Zhejiang Province, China (Grant No. Y4110357).

  6. Molecular step(s) of force generation: temperature-perturbation experiments on muscle fibres.

    PubMed

    Ranatunga, K W; Coupland, M E

    2003-01-01

    The steady active muscle force is reduced, but the force generation induced by a standard temperature jump becomes 2-3 fold faster with increased inorganic phosphate level, [Pi]. The increase in the rate of force generation also exhibits saturation at higher [Pi] levels and the relation is hyperbolic. These observations are consistent with a kinetic scheme where rapid Pi release by actomyosin crossbridges in muscle is preceded by the force generation step. Such a scheme accounts for the sigmoidal temperature dependence of steady active force and its sensitivity to [Pi]. The [Pi] dependence of force recovery after stretch (positive strain) is also hyperbolic, suggesting that the "pre Pi-release force generation step" is strain-sensitive--as expected. However, length-release (negative strain) force transients are not [Pi] sensitive indicating an asymmetry, but its significance and also the kinetic step underlying force recovery from negative strain remain unclear. PMID:15098690

  7. Operating experience with four 200 kW Mod-0A wind turbine generators

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.; Saunders, A. L.; Nyland, T. W.; Shaltens, R. K.

    1982-01-01

    The windpowered generator, Mod-0A, and its advantages and disadvantages, particularly as it affects reliability, are discussed. The machine performance with regard to power availability and power output is discussed.

  8. Molten salt steam generator subsystem research experiment. Phase I, final report. Volume 2. Appendices

    SciTech Connect

    Not Available

    1984-10-01

    Information is given on: steam generator subsystem requirements specification, pressure boundary code calculations, structural analysis compliance check lists, supplemental elevated temperature rules, system simulation analysis, control system design, and a phase II proposal. (LEW)

  9. Operational experience and maintenance programs of Transamerica Delaval, Inc., diesel generators

    SciTech Connect

    Rajan, J.R.

    1994-05-01

    Concerns regarding the reliability of large-bore, medium-speed diesel generators manufactured by Transamerica Delaval, Inc. (TDI) for application at domestic nuclear plants were first prompted by a crankshaft failure at Shoreham Nuclear Power Station in August 1983. A number of diesel generator components were identified which had potential deficiencies from a manufacturing and operational standpoint. In response to these problems, 11 (now 8) U.S. nuclear utility owners formed a TDI Diesel Generator Owners Group (Owners Group) to address operational and regulatory issues relative to diesel generator sets used for standby emergency power. The Owners` Group performed extensive design reviews of all key engine components and developed recommendations to be implemented by the individual owners concerning needed component replacements and modifications, component inspections to validate the {open_quotes}as-manufactured{close_quotes} and {open_quotes}as-assembled{close_quotes} quality of key engine components, engine testing, and an enhanced maintenance and surveillance program.

  10. Primordial gravitational waves from the space-condensate inflation model

    NASA Astrophysics Data System (ADS)

    Koh, Seoktae; Lee, Bum-Hoon; Tumurtushaa, Gansukh

    2016-04-01

    We consider the space-condensate inflation model to study the primordial gravitational waves generated in the early Universe. We calculate the energy spectrum of gravitational waves induced by the space-condensate inflation model for the full frequency range with the assumption that the phase transition between two consecutive regimes is abrupt during the evolution of the Universe. The suppression of the energy spectrum is found in our model for the decreasing frequency of gravitational waves depending on the model parameter. To realize the suppression of the energy spectrum of the primordial gravitational waves, we study the existence of the early phase transition during inflation for the space-condensate inflation model.

  11. The NSF Condensed Matter and Materials Theory Program

    NASA Astrophysics Data System (ADS)

    Hess, Daryl

    The Condensed Matter and Materials Theory (CMMT) Program in the Division of Materials Research is the home of condensed matter theory at the National Science Foundation. CMMT awards reflect a vibrant community with expanding scientific horizons and opportunities. I will present an overview of the CMMT program. Opportunities for theory and computation to open new directions and stimulate emerging frontiers will be discussed. Engaging research across disciplinary boundaries maintains the vitality of the field, leads to an agile next generation of theoretical and computational condensed matter physicists, and advances understanding of the world on the scale of life.

  12. "Hard to crack": experiences of community integration among first- and second-generation Asian MSM in Canada.

    PubMed

    Nakamura, Nadine; Chan, Elic; Fischer, Benedikt

    2013-07-01

    Asians are the largest racial minority in Canada making up 11% of the population and represented over 60% of new immigrants between 2001 and 2006. We examined the experiences of community integration for first-generation (n = 27) and second-generation (n = 22) Asian Canadian men who have sex with men (MSM) in their ethnic and gay communities. Through focus group interviews, we explored their level of connectedness and the level of discrimination they experienced in the two communities. Findings indicate that Asian MSM in general perceived their ethnic community as homophobic, stemming from a combination of seeing sex as taboo, stereotypes about being gay, and the affiliation with religion. Although the literature indicates that immigrants rely on the support of their ethnic communities, our finding suggest that this is not the case for Asian immigrant MSM, who in our sample reported feeling less connected compared to their second-generation counterparts. For the gay community, our sample reported mixed experiences as some regarded it as welcoming, whereas others described it as racist. However, these experiences did not differ by generational status. Many were aware of explicit messages stating "No Asians" in dating contexts, while at the same time being aware that some older White men were interested in dating Asians exclusively. Barriers to integration in both communities may contribute to feelings of isolation. Theoretical implications are discussed. PMID:23875850

  13. Pion condensation in holographic QCD

    SciTech Connect

    Albrecht, Dylan; Erlich, Joshua

    2010-11-01

    We study pion condensation at zero temperature in a hard-wall holographic model of hadrons with isospin chemical potential. We find that the transition from the hadronic phase to the pion condensate phase is first order except in a certain limit of model parameters. Our analysis suggests that immediately across the phase boundary the condensate acts as a stiff medium approaching the Zel'dovich limit of equal energy density and pressure.

  14. Condensation in hypersonic nitrogen wind tunnels

    NASA Technical Reports Server (NTRS)

    Lederer, Melissa A.; Yanta, William J.; Ragsdale, William C.; Hudson, Susan T.; Griffith, Wayland C.

    1990-01-01

    Experimental observations and a theoretical model for the onset and disappearance of condensation are given for hypersonic flows of pure nitrogen at M = 10, 14 and 18. Measurements include Pitot pressures, static pressures and laser light scattering experiments. These measurements coupled with a theoretical model indicate a substantial non-equilibrium supercooling of the vapor phase beyond the saturation line. Typical results are presented with implications for the design of hypersonic wind tunnel nozzles.

  15. Parton Saturation and the Color Glass Condensate

    NASA Astrophysics Data System (ADS)

    Kovchegov, Yuri V.

    2007-03-01

    We review recent developments in the field of parton saturation and the Color Glass Condensate. We discuss the classical gluon fields of McLerran-Venugopalan model. We explain how small- x non-linear quantum evolution corrections can be included into the total cross section for deep inelastic scattering. We proceed by reviewing saturation physics predictions for the particle production in p( d) A collisions and conclude by demonstrating how such predictions were confirmed by the RHIC experiments.

  16. Gravity waves from the nonperturbative decay of condensates along supersymmetric flat directions.

    PubMed

    Dufaux, Jean-François

    2009-07-24

    Nonperturbative effects may lead to an explosive decay of flat direction condensates in supersymmetric theories. We confirm the efficiency of this process with lattice simulations: After only one to five rotations of the condensates in their complex plane, most of their energy is converted into inhomogeneous fluctuations. This generates a gravitational wave background, which depends on the inflaton sector and falls in the hertz-kilohertz frequency range today. These gravity waves can be observable by upcoming experiments such as Advanced LIGO and depend crucially on (i) the initial vacuum expectation value of flat directions when they start to oscillate, (ii) their soft supersymmetry-breaking mass, and (iii) the reheat temperature of the Universe. This signal could open a new observational window on inflation and low-energy supersymmetry. PMID:19659339

  17. [Growth and development of plants in a row of generations under the conditions of space flight (experiment Greenhouse-5)

    NASA Technical Reports Server (NTRS)

    Levinskikh, M. A.; Sychev, V. N.; Derendiaeva, T. A.; Signalova, O. B.; Podol'skii, I. G.; Avdeev, S. V.; Bingheim, G. E.; Campbell, W. F. (Principal Investigator)

    2001-01-01

    Results of the experiment aimed at harvesting a second space generation of wheat var. Apogee in Mir greenhouse Svet (experiment GREENHOUSE-5) are presented. In space flight, germination rate of space seeds from the first crop made up 89% against 100% of the ground seeds. The full biological ripeness was observed in 20 plants grown from the ground seeds and one plant grown from the space seeds following 80- to 90-d vegetation. The plant of the second space generation was morphologically different neither from the species in the first space crop nor from the ground controls. To study the biological characteristics of Apogee seeds gathered in the first and second crops in spaceflight experiment GREENHOUSE-5, the seeds were planted on their return to the laboratory. Morphometric analysis showed that they were essentially similar to the controls. Hence, the space experiments in Mir greenhouse Svet performed during 1998-1999 gave proof that plants cultivated in microgravity can pass the ontogenetic cycle more than once. However, initial results of the investigations into growth and development of plants through several generations are still in-sufficient to speak of possible delayed effects of the spaceflight factors (microgravity, multicomponent radiation, harmful trace contaminants etc.).

  18. Development of Next Generation Memory Test Experiment for Deployment on a Small Satellite

    NASA Technical Reports Server (NTRS)

    MacLeod, Todd; Ho, Fat D.

    2012-01-01

    The original Memory Test Experiment successfully flew on the FASTSAT satellite launched in November 2010. It contained a single Ramtron 512K ferroelectric memory. The memory device went through many thousands of read/write cycles and recorded any errors that were encountered. The original mission length was schedule to last 6 months but was extended to 18 months. New opportunities exist to launch a similar satellite and considerations for a new memory test experiment should be examined. The original experiment had to be designed and integrated in less than two months, so the experiment was a simple design using readily available parts. The follow-on experiment needs to be more sophisticated and encompass more technologies. This paper lays out the considerations for the design and development of this follow-on flight memory experiment. It also details the results from the original Memory Test Experiment that flew on board FASTSAT. Some of the design considerations for the new experiment include the number and type of memory devices to be used, the kinds of tests that will be performed, other data needed to analyze the results, and best use of limited resources on a small satellite. The memory technologies that are considered are FRAM, FLASH, SONOS, Resistive Memory, Phase Change Memory, Nano-wire Memory, Magneto-resistive Memory, Standard DRAM, and Standard SRAM. The kinds of tests that could be performed are read/write operations, non-volatile memory retention, write cycle endurance, power measurements, and testing Error Detection and Correction schemes. Other data that may help analyze the results are GPS location of recorded errors, time stamp of all data recorded, radiation measurements, temperature, and other activities being perform by the satellite. The resources of power, volume, mass, temperature, processing power, and telemetry bandwidth are extremely limited on a small satellite. Design considerations must be made to allow the experiment to not interfere

  19. Condensation on a noncollapsing vapor bubble in a subcooled liquid

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.; Simoneau, R. J.

    1979-01-01

    An experimental procedure is presented by which an estimate can be made of the condensation coefficient on a noncollapsing stationary vapor bubble in subcooled liquid nitrogen. Film boiling from a thin wire was used to generate vapor bubbles which remain fixed to the wire at their base. A balance was established between the evaporation in the thin annular region along the wire and the condensation in the vapor bubbles.

  20. Condensation on a noncollapsing vapor bubble in a subcooled liquid

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.; Simoneau, R. J.

    1979-01-01

    An experimental procedure is presented by which an estimate can be made of the condensation coefficient on a noncollapsing stationary vapor bubble in subcooled liquid nitrogen. The present experimental study utilizes film boiling from a thin wire to generate vapor bubbles which remain fixed to the wire at their base. A balance was established between the evaporation in the thin annular region along the wire and the condensation in the vapor bubbles.

  1. An experience in mesh generation for three-dimensional calculation of potential flow around a rotating propeller

    NASA Technical Reports Server (NTRS)

    Jou, W.-H.

    1982-01-01

    An attempt is made to develop a three-dimensional, finite volume computational code for highly swept, twisted, small aspect ratio propeller blades with supersonic tip speeds, in a way that accounts for cascade effects, hub-induced flow, and nonlinear transonic effects. Attention is presently given to the generation of a computational mesh for such a complex propeller configuration, with the aim of sharing developmental process experience. The problem treated is unique, in that blade chord, blade length, hub length and blade-to-blade distance represent several characteristic length scales among which there is considerable disparity. An ad hoc mesh-generation scheme is accordingly developed.

  2. The third generation (e,e'K+) hypernuclear spectroscopic experiment at JLab Hall-C

    SciTech Connect

    Daisuke Kawama, Jlab E05-115 Collaboration

    2012-04-01

    We carried out a Lambda hypernuclear spectroscopic experiment at Jefferson Lab in 2009, aiming at precise spectroscopy of {Lambda} hypernuclei in the wide-mass region up to A = 52. The experiment has been successfully carried out and now we are in data analysis phase. The most important point of the analysis is precision mass scale calibration by comparing mass spectra of Lambda hypernuclei and Lambda and {Sigma}{sup 0} hyperons in the same setup with {Lambda} hypernuclear spectroscopic experiment. We show a preliminary result of the calibration analysis with {sup 12}{sub {Lambda}}B spectrum.

  3. Optical Comb Generation for Streak Camera Calibration for Inertial Confinement Fusion Experiments

    SciTech Connect

    Ronald Justin, Terence Davies, Frans Janson, Bruce Marshall, Perry Bell, Daniel Kalantar, Joseph Kimbrough, Stephen Vernon, Oliver Sweningsen

    2008-09-18

    The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is coming on-line to support physics experimentation for the U.S. Department of Energy (DOE) programs in Inertial Confinement Fusion (ICF) and Stockpile Stewardship (SS). Optical streak cameras are an integral part of the experimental diagnostics instrumentation at NIF. To accurately reduce streak camera data a highly accurate temporal calibration is required. This article describes a technique for simultaneously generating a precise +/- 2 ps optical marker pulse (fiducial reference) and trains of precisely timed, short-duration optical pulses (so-called “comb” pulse trains) that are suitable for the timing calibrations. These optical pulse generators are used with the LLNL optical streak cameras. They are small, portable light sources that, in the comb mode, produce a series of temporally short, uniformly spaced optical pulses, using a laser diode source. Comb generators have been produced with pulse-train repetition rates up to 10 GHz at 780 nm, and somewhat lower frequencies at 664 nm. Individual pulses can be as short as 25-ps FWHM. Signal output is via a fiber-optic connector on the front panel of the generator box. The optical signal is transported from comb generator to streak camera through multi-mode, graded-index optical fiber.

  4. Experiments on Charge Generation in Cross-linked Polyethylene and Ethylene-Propylene Copolymer

    NASA Astrophysics Data System (ADS)

    Sekii, Yasuo; Taya, Atsushi; Suzuki, Hirokazu; Maeno, Takashi

    To study the space charge generation in cross-linked polyethylene (XLPE) and ethylene propylene copolymer (EPR), space charge profiles in both materials are measured using PEA method. The experimental results demonstrated that a big difference was discovered in the detected charge profiles between XLPE and EPR. We discovered that the diffusion of charge is significantly faster in EPR than in XLPE. The authors confirmed that the negative hetero-charge is generated near the positive electrode in EPR when moisture are coexisting with acetophenone. The effects of antioxidants on the generation of hetero-space charges in XLPE and EPR are also studied using XLPE and EPR samples containing different kinds of phenolic and sulfur type antioxidant. The authors discovered that hetero-charge is generated in XLPE and EPR containing sulfur type, or sulfur-containing phenolic, antioxidant when acetophenone are existing in the material. The hetero-charge generation is inferred to be caused by the combined effect between acetophenone and the component containing sulfur atoms of the antioxidants.

  5. Experiments on bubble generation by a hydrofoil moving beneath the water surface for reducing ship drag

    NASA Astrophysics Data System (ADS)

    Kumagai, Ichiro; Murai, Yuichi; Takahashi, Yoshiaki; Sakamaki, Haruki; Tsukahara, Takahiro; Ozaki, Tsubasa; Tasaka, Yuji; Oishi, Yoshihiko

    2014-04-01

    We have invented two types of hydrofoil bubble generator for drag reduction of ship that can reduce the energy for air bubble generation on the ship hull. Their fundamental process of air entrainment and subsequent bubble generation by the hydrofoil facility are described by a simple fluid dynamic model. We experimentally determined the critical velocity of the bubble generation and the relationship between air volume flow rate and the hydrofoil velocity. The magnitude of the negative pressure produced above the hydrofoil, which is a driving force of the air entrainment, depends on the shape of the hydrofoil, gap ratio (normalized depth of the hydrofoil), Reynolds number, Froude number, and angle of attack. Recent applications of the drag-reduction technology with air bubbles to a ship save about 10%-15% of the total energy consumption of the ship. The device works as a self-priming pump when the draft of the ship is shallow (< ˜5 m) as predicted by the theory. For ships of deeper draft, the device needs the assistance of an air compressor. Because the magnitude of the negative pressure above the hydrofoil depends on the flow condition around the hydrofoil, proper operation of compressors is necessary. We also show experimental results on optimization of hydrofoils to enhance the hydrofoil performance of air entrainment and air bubble generation.

  6. Design of the Next Generation Nuclear Plant Graphite Creep Experiments for Irradiation in the Advanced Test Reactor

    SciTech Connect

    S. Blaine Grover

    2009-05-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Program will be irradiating six gas reactor graphite creep experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the new United States Department of Energy’s lead laboratory for nuclear energy development. The ATR is one of the world’s premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These graphite irradiations are being accomplished to support development of the next generation reactors in the United States. The graphite experiments will be irradiated over the next six to eight years to support development of a graphite irradiation performance data base on the new nuclear grade graphites now available for use in high temperature gas reactors. The goals of the irradiation experiments are to obtain irradiation performance data at different temperatures and loading conditions to support design of the Next Generation Nuclear Plant Very High Temperature Gas Reactor, as well as other future gas reactors. The experiments will each consist of a single capsule that will contain seven separate stacks of graphite specimens. Six of the specimen stacks will have half of their graphite specimens under a compressive load, while the other half of the specimens will not be subjected to a compressive load during irradiation. The six stacks will be organized into pairs with a different compressive load being applied to the top half of each pair of specimen stacks. The seventh stack will not have a compressive load on the graphite specimens during irradiation. The specimens will be irradiated in an inert sweep gas atmosphere with on-line temperature and compressive load monitoring and control. There will also be the capability of sampling the sweep gas effluent to determine if any

  7. Early utility experience with wind power generation. Volume 2. Pacific Gas and Electric Company, Solano County project. Final report

    SciTech Connect

    McCabe, T.; Henry, G.; Tennis, M.; Goldenblatt, M.

    1984-01-01

    This report is one of three presenting the results of EPRI Research Project 1590-1, Evaluation of Electric Utility Experience with Wind Power Generation. The objective of this project was to develop an improved understanding of wind power generation, in particular the process a utility must undergo to initiate and carry out a wind turbine project. The primary tasks of RP1590-1 were to document and evaluate the experience of two utilities with megawatt-scale wind turbine installations from project inception to the wind turbine's first rotation. This technical report presents the experiences of the Pacific Gas and Electric Company (PG and E) with its wind turbine installation at Solano County, California. All documents and reports pertaining to PG and E's experience with wind energy at Solano County were reviewed and excerpts made of the highlights. Gaps in the documentation were filled by talking with appropriate people. Site visits were conducted to monitor current activity. The information obtained was evaluated for its generic relevance and benefit to other utilities. The chronology of steps taken by PG and E in implementing the Solano wind turbine experience and some of the lessons learned are included in the report. In each section, important activities, critical assumptions, and interesting insights which might benefit other utility wind programs are identified.

  8. Dual stator winding variable speed asynchronous generator: optimal design and experiments

    NASA Astrophysics Data System (ADS)

    Tutelea, L. N.; Deaconu, S. I.; Popa, G. N.

    2015-06-01

    In the present paper is carried out a theoretical and experimental study of dual stator winding squirrel cage asynchronous generator (DSWA) behavior in the presence of saturation regime (non-sinusoidal) due to the variable speed operation. The main aims are the determination of the relations of calculating the equivalent parameters of the machine windings to optimal design using a Matlab code. Issue is limited to three phase range of double stator winding cage-induction generator of small sized powers, the most currently used in the small adjustable speed wind or hydro power plants. The tests were carried out using three-phase asynchronous generator having rated power of 6 [kVA].

  9. Dual stator winding variable speed asynchronous generator: magnetic equivalent circuit with saturation, FEM analysis and experiments

    NASA Astrophysics Data System (ADS)

    Tutelea, L. N.; Muntean, N.; Deaconu, S. I.; Cunţan, C. D.

    2016-02-01

    The authors carried out a theoretical and experimental study of dual stator winding squirrel cage asynchronous generator (DSWA) behaviour in the presence of saturation regime (non-sinusoidal) due to the variable speed operation. The main aims are the determination of the relations of calculating the equivalent parameters of the machine windings, FEM validation of parameters and characteristics with free FEMM 4.2 computing software and the practice experimental tests for verifying them. Issue is limited to three phase range of double stator winding cage-asynchronous generator of small sized powers, the most currently used in the small adjustable speed wind or hydro power plants. The tests were carried out using three-phase asynchronous generator having rated power of 6 [kVA].

  10. Behaviour of Rotating Bose Einstein Condensates Under Shrinking

    NASA Astrophysics Data System (ADS)

    Zhai, Hui; Zhou, Qi

    2005-01-01

    When the repulsive interaction strength between atoms decreases, the size of a rotating Bose-Einstein condensate will consequently shrink. We find that the rotational frequency will increase during the shrinking of condensate, which is a quantum mechanical analogy to ballet dancing. Compared to a non-rotating condensate, the size of a rotating BEC will eventually be saturated at a finite value when the interaction strength is gradually reduced. We also calculate the vortex dynamics induced by the atomic current, and discuss the difference of vortex dynamics in this case and that observed in a recent experiment carried out by the JILA group [Phys. Rev. Lett. 90 (2003) 170405].

  11. Optical turbulence and spectral condensate in long fibre lasers

    PubMed Central

    Turitsyna, E. G.; Falkovich, Gregory; El-Taher, Atalla; Shu, Xuewen; Harper, Paul; Turitsyn, Sergei K.

    2012-01-01

    We study numerically optical turbulence using the particular example of a recently created, ultra-long fibre laser. For normal fibre dispersion, we observed an intermediate state with an extremely narrow spectrum (condensate), which experiences instability and a sharp transition to a fluctuating regime with a wider spectrum. We demonstrate that the number of modes has an impact on the condensate's lifetime. The smaller the number of modes, the more resistant is the condensate to perturbations. Experimental results show a good agreement with numerical simulations. PMID:22870062

  12. Modeling acid-gas generation from boiling chloride brines

    SciTech Connect

    Zhang, Guoxiang; Spycher, Nicolas; Sonnenthal, Eric; Steefel, Carl

    2009-11-16

    This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes that are modeled include boiling of highly concentrated solutions, gas transport, and gas condensation accompanied by the dissociation of acid gases, causing low-pH condensate. Simple calculations are first carried out to evaluate condensate pH as a function of HCl gas fugacity and condensed water fraction for a vapor equilibrated with saturated calcium chloride brine at 50-150 C and 1 bar. The distillation of a calcium-chloride-dominated brine is then simulated with a reactive transport model using a brine composition representative of partially evaporated calcium-rich pore waters at Yucca Mountain. Results show a significant increase in boiling temperature from evaporative concentration, as well as low pH in condensates, particularly for dynamic systems where partial condensation takes place, which result in enrichment of HCl in condensates. These results are in qualitative agreement with experimental data from other studies. The combination of reactive transport with multicomponent brine chemistry to study evaporation, boiling, and the potential for acid gas generation at the proposed Yucca Mountain repository is seen as an improvement relative to previously applied simpler batch evaporation models. This approach allows the evaluation of thermal, hydrological, and chemical (THC) processes in a coupled manner, and modeling of settings much more relevant to actual field conditions than the distillation experiment considered. The actual and modeled distillation experiments do not represent

  13. Modeling acid-gas generation from boiling chloride brines

    PubMed Central

    2009-01-01

    Background This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes that are modeled include boiling of highly concentrated solutions, gas transport, and gas condensation accompanied by the dissociation of acid gases, causing low-pH condensate. Results Simple calculations are first carried out to evaluate condensate pH as a function of HCl gas fugacity and condensed water fraction for a vapor equilibrated with saturated calcium chloride brine at 50-150°C and 1 bar. The distillation of a calcium-chloride-dominated brine is then simulated with a reactive transport model using a brine composition representative of partially evaporated calcium-rich pore waters at Yucca Mountain. Results show a significant increase in boiling temperature from evaporative concentration, as well as low pH in condensates, particularly for dynamic systems where partial condensation takes place, which result in enrichment of HCl in condensates. These results are in qualitative agreement with experimental data from other studies. Conclusion The combination of reactive transport with multicomponent brine chemistry to study evaporation, boiling, and the potential for acid gas generation at the proposed Yucca Mountain repository is seen as an improvement relative to previously applied simpler batch evaporation models. This approach allows the evaluation of thermal, hydrological, and chemical (THC) processes in a coupled manner, and modeling of settings much more relevant to actual field conditions than the distillation experiment considered. The actual and modeled distillation

  14. Preliminary results of the on-demand vortex-generator experiments

    NASA Technical Reports Server (NTRS)

    Saddoughi, Seyed G.

    1995-01-01

    This is a report on the continuation of our experimental investigations (Saddoughi 1994) of 'on-demand' vortex generators. Conventional vortex generators as found on aircraft wings are mainly for suppression of separation during the off-design conditions. In cruise they perform no useful function and exert a significant drag penalty. Therefore, replacement of fixed rectangular or delta-wing generators by devices that could be activated when needed would be of interest. Also in our previous report, we described one example of an 'on-demand' device, which was developed by Jacobson & Reynolds (1995) at Stanford University, suitable for manufacture by micro-electro-mechanical technology. This device consists of a surface cavity elongated in the stream direction and covered with a lid cantilevered at the upstream end. The lid, which is a metal sheet with a sheet of piezoelectric ceramic bonded to it, lies flush with the boundary. On application of a voltage the ceramic expands or contracts; however, adequate amplitude can be obtained only by running at the cantilever resonance frequency and applying amplitude modulation: for 2.5 mm x 20 mm cantilevered lids, they obtained maximum tip displacements of the order of 100 pm. Thus fluid is expelled from the cavity through the gap around the lid on the downstroke. They used an asymmetrical gap configuration and found that periodic emerging jets on the narrow side induced periodic longitudinal vorticity into the boundary layer. Their device was used to modify the inner layer of the boundary layer for skin-friction reduction. The same method could be implemented for the replacement of the conventional vortex generators; however, to promote mixing and suppress separation we needed to deposit longitudinal vortices into the outer layer of the boundary layer, which required a larger vortex generator than the device built by Jacobson & Reynolds. Our vortex generator was built with a mechanically-driven cantilevered lid with an

  15. Comparisons of neutrino event generators from an oscillation-experiment perspective

    SciTech Connect

    Mayer, Nathan

    2015-05-15

    Monte Carlo generators are crucial to the analysis of high energy physics data, ideally giving a baseline comparison between the state-of-art theoretical models and experimental data. Presented here is a comparison between three of final state distributions from the GENIE, Neut, NUANCE, and NuWro neutrino Monte Carlo event generators. The final state distributions chosen for comparison are: the electromagnetic energy fraction in neutral current interactions, the energy of the leading π{sup 0} vs. the scattering angle for neutral current interactions, and the muon energy vs. scattering angle of ν{sub µ} charged current interactions.

  16. Comparisons of neutrino event generators from an oscillation-experiment perspective

    NASA Astrophysics Data System (ADS)

    Mayer, Nathan

    2015-05-01

    Monte Carlo generators are crucial to the analysis of high energy physics data, ideally giving a baseline comparison between the state-of-art theoretical models and experimental data. Presented here is a comparison between three of final state distributions from the GENIE, Neut, NUANCE, and NuWro neutrino Monte Carlo event generators. The final state distributions chosen for comparison are: the electromagnetic energy fraction in neutral current interactions, the energy of the leading π0 vs. the scattering angle for neutral current interactions, and the muon energy vs. scattering angle of νµ charged current interactions.

  17. Genetic control of the environmental variance for birth weight in seven generations of a divergent selection experiment in mice.

    PubMed

    Formoso-Rafferty, N; Cervantes, I; Ibáñez-Escriche, N; Gutiérrez, J P

    2016-06-01

    Data from seven generations of a divergent selection experiment designed for environmental variability of birth weight were analysed to estimate genetic parameters and to explore signs of selection response. A total of 10 783 birth weight records from 638 females and 1127 litters in combination with 10 007 pedigree records were used. Each record of birth weight was assigned to the mother of the pup in a heteroscedastic model, and after seven generations of selection, evidence of success in the selection process was shown. A Bayesian analysis showed that success of the selection process started from the first generation for birth weight and from the second generation for its environmental variability. Genetic parameters were estimated across generations. However, only from the third generation onwards were the records useful to consider the results to be reliable. The results showed a consistent positive and low genetic correlation between the birth weight trait and its environmental variability, which could allow an independent selection process. This study has demonstrated that the genetic control of the birth weight environmental variability is possible in mice. Nevertheless, before the results are applied directly in farm animals, it would be worth confirming any other implications on other important traits, such as robustness, longevity and welfare. PMID:26150168

  18. Black Hole Bose Condensation

    NASA Astrophysics Data System (ADS)

    Vaz, Cenalo; Wijewardhana, L. C. R.

    2013-12-01

    General consensus on the nature of the degrees of freedom responsible for the black hole entropy remains elusive despite decades of effort dedicated to the problem. Different approaches to quantum gravity disagree in their description of the microstates and, more significantly, in the statistics used to count them. In some approaches (string theory, AdS/CFT) the elementary degrees of freedom are indistinguishable, whereas they must be treated as distinguishable in other approaches to quantum gravity (eg., LQG) in order to recover the Bekenstein-Hawking area-entropy law. However, different statistics will imply different behaviors of the black hole outside the thermodynamic limit. We illustrate this point by quantizing the Bañados-Teitelboim-Zanelli (BTZ) black hole, for which we argue that Bose condensation will occur leading to a "cold", stable remnant.

  19. Microgravity condensing heat exchanger

    NASA Technical Reports Server (NTRS)

    Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor); North, Andrew (Inventor); Weislogel, Mark M. (Inventor)

    2011-01-01

    A heat exchanger having a plurality of heat exchanging aluminum fins with hydrophilic condensing surfaces which are stacked and clamped between two cold plates. The cold plates are aligned radially along a plane extending through the axis of a cylindrical duct and hold the stacked and clamped portions of the heat exchanging fins along the axis of the cylindrical duct. The fins extend outwardly from the clamped portions along approximately radial planes. The spacing between fins is symmetric about the cold plates, and are somewhat more closely spaced as the angle they make with the cold plates approaches 90.degree.. Passageways extend through the fins between vertex spaces which provide capillary storage and communicate with passageways formed in the stacked and clamped portions of the fins, which communicate with water drains connected to a pump externally to the duct. Water with no entrained air is drawn from the capillary spaces.

  20. Quantification of parameters influencing methane generation due to biodegradation of municipal solid waste in landfills and laboratory experiments.

    PubMed

    Fei, Xunchang; Zekkos, Dimitrios; Raskin, Lutgarde

    2016-09-01

    The energy conversion potential of municipal solid waste (MSW) disposed of in landfills remains largely untapped because of the slow and variable rate of biogas generation, delayed and inefficient biogas collection, leakage of biogas, and landfill practices and infrastructure that are not geared toward energy recovery. A database consisting of methane (CH4) generation data, the major constituent of biogas, from 49 laboratory experiments and field monitoring data from 57 landfills was developed. Three CH4 generation parameters, i.e., waste decay rate (k), CH4 generation potential (L0), and time until maximum CH4 generation rate (tmax), were calculated for each dataset using U.S. EPA's Landfill Gas Emission Model (LandGEM). Factors influencing the derived parameters in laboratory experiments and landfills were investigated using multi-linear regression analysis. Total weight of waste (W) was correlated with biodegradation conditions through a ranked classification scheme. k increased with increasing percentage of readily biodegradable waste (Br0 (%)) and waste temperature, and reduced with increasing W, an indicator of less favorable biodegradation conditions. The values of k obtained in the laboratory were commonly significantly higher than those in landfills and those recommended by LandGEM. The mean value of L0 was 98 and 88L CH4/kg waste for laboratory and field studies, respectively, but was significantly affected by waste composition with ranges from 10 to 300L CH4/kg. tmax increased with increasing percentage of biodegradable waste (B0) and W. The values of tmax in landfills were higher than those in laboratory experiments or those based on LandGEM's recommended parameters. Enhancing biodegradation conditions in landfill cells has a greater impact on improving k and tmax than increasing B0. Optimizing the B0 and Br0 values of landfilled waste increases L0 and reduces tmax. PMID:26525969

  1. Discovering Shared Experiences of Second Generation Community College Employees: A Grounded Theory Study

    ERIC Educational Resources Information Center

    Studebaker, Eric J.

    2012-01-01

    The second generation community college employee had not been a target population of any previous research in the field of higher education. This study added to a broader understanding of employees, their various characteristics, and the implications of those characteristics. The purpose of this study was to develop a grounded theory defining the…

  2. Theorizing Multidimensional Identity Negotiation: Reflections on the Lived Experiences of First-Generation College Students

    ERIC Educational Resources Information Center

    Orbe, Mark P.

    2008-01-01

    Drawing from recent research on first-generation college (FGC) students, this chapter advances an interdisciplinary theoretical framework for understanding how these students enact multiple aspects of their personal, cultural, and social identities. I use dialectical and cross-cultural adaptation theories as a foundation to extend examinations of…

  3. First-Generation College Students' 1st-Year College Experiences: Challenges Attending a Private University

    ERIC Educational Resources Information Center

    Reid, Josephine

    2013-01-01

    First-generation college students (FGCS) face challenges when switching from high school to college and during their 1st-year in college. Additionally, FGCS may have difficulty understanding the steps required to prepare for and enroll in postsecondary education. The social capital theory examines support of social, academic, and cultural networks…

  4. A Cultural Mismatch: The Experience of First-Generation College Students in Elite Universities

    ERIC Educational Resources Information Center

    Stephens, Nicole M.

    2010-01-01

    "First-generation" college students, whose parents have not attended college, are an increasing presence at elite colleges and universities. Admitting these students, however, is not enough to ensure that they can take full advantage of the opportunities available to them in college and succeed there. Indeed, research indicates that…

  5. Developing the next Generation of Education Researchers: UCLA's Experience with the Spencer Foundation Research Training Grant

    ERIC Educational Resources Information Center

    Dorr, Aimee; Arms, Emily; Hall, Valerie

    2008-01-01

    Background/Context: In the early 1990s, the Spencer Foundation instituted an Institutional Research Training Grant (RTG) program to improve the preparation of the next generation of education researchers. UCLA received an RTG in the first round of competition. Purpose/Objective/Research Question/Focus of Study: UCLA's Spencer RTG program sought to…

  6. Perceptions of the Persistent: Academic Experiences of First Generation Community College Students

    ERIC Educational Resources Information Center

    Amos, Anthea E.

    2010-01-01

    While open access is still possible at community colleges and state colleges in Florida through the Florida College System, and the numbers of those enrolling are increasing, retention of first generation students is still an issue. Florida has increased the opportunity to attend college by limiting the barrier that inadequate financial support…

  7. Faculty Perceptions of the First-Generation Student Experience and Programs at Tribal Colleges

    ERIC Educational Resources Information Center

    Schmidt, Jacqueline J.; Akande, Yemi

    2011-01-01

    Although an increasing number of Native Americans are enrolling as first-generation college students (FGS) at postsecondary institutions, the percentage of those attaining bachelor's degrees or higher remains relatively low--11 percent, compared with more than 25 percent for the general population. Native Americans face not only the retention…

  8. Geometry acquisition and grid generation: Recent experiences with complex aircraft configurations

    NASA Technical Reports Server (NTRS)

    Gatzke, Timothy D.; Labozzetta, Walter F.; Cooley, John W.; Finfrock, Gregory P.

    1992-01-01

    Important issues involved in working with complex geometries are discussed. Approaches taken to address complex geometry issues in the McDonnell Aircraft Computational Grid System and related geometry processing tools are discussed. The efficiency of acquiring a suitable geometry definition, the need to manipulate the geometry, and the time and skill level required to generate the grid while preserving geometric fidelity are discussed.

  9. First-Generation College Students: Additional Evidence on College Experiences and Outcomes

    ERIC Educational Resources Information Center

    Pascarella, Ernest T.; Pierson, Christopher T.; Wolniak, Gregory C.; Terenzini, Patrick T.

    2004-01-01

    The growing demographic diversity of the under-graduate student body in American postsecondary education has been well documented over an extended period of time. One result of this increased diversity is the substantial number of "first-generation" college students from families where neither parent had more than a high-school education. For…

  10. Experiments on the unsteady flow field and noise generation in a centrifugal pump impeller

    NASA Astrophysics Data System (ADS)

    Choi, Jong-Soo; McLaughlin, Dennis K.; Thompson, Donald E.

    2003-06-01

    This paper reports on an experimental investigation of large-scale flowfield instabilities in a pump rotor and the process of noise generation by these instabilities. Measurements of the fluctuating components of velocity and surface pressure were made with hot-wire probes and surface mounted pressure transducers on a seven bladed back swept centrifugal water pump impeller operating with air as the working fluid. The impeller was operated without a volute or scroll diffuser, thereby eliminating any sound generation from pressure fluctuations on the volute cutoff. Thus the study focused on flow field and noise components other than the blade passage frequency (and its harmonics). The primary goal of the study was to provide fundamental information on the unsteady flow processes, particularly those associated with the noise generation in the device. It was further anticipated that detailed flow measurements would be useful for the validation of future computational simulations. The measured data at the discharge show a jet-wake type of flow pattern which results in a strong vorticity field. The flow with high velocity found on the pressure side of the impeller tends to move to the low-pressure region present at the suction side of the passage as a form of roll-up around the blade trailing edge. This motion causes an unsteady flow separation at the suction side of the blade and consequently disturbs the flow in the adjacent passage. By interacting with the impeller blades near the trailing edges, this instability flow causes a periodic pressure fluctuation on the blade surface and generates noise by a trailing edge generation mechanism. The spectrum of surface pressure measured at the trailing edge of each blade reveals a cluster of peaks which were identified with azimuthal mode numbers. The correlation between the acoustic farfield pressure and the surface pressure on the impeller blade has proven that the azimuthal modes synchronized with the number of impeller

  11. 1 and 2 Dimensional Bose Einstein Condensates

    NASA Astrophysics Data System (ADS)

    Vogels, Johnny; Gorlitz, Axel; Raman, Chandra; Gustavson, Todd; Drndic, Marija; Leanhardt, Aaron; Abo-Shaeer, Jamil; Loew, Robert; Ketterle, Wolfgang

    2001-05-01

    We have created condensates in which the zero point motion exceeds the mean field enegy in either 2 (1D-condensate) or 1 dimension (2D-condensate). We describe the optical traps and magnetic traps being used, their limitations, and the regimes that are accessible. Some of our 1D condensates should have limited coherence properties (quasi-condensates).

  12. Amine catalyzed condensation of tetraethylorthosilicate

    NASA Technical Reports Server (NTRS)

    Jones, S.

    2001-01-01

    The catalysis of the condensation of hydrolyzed metal alkoxides by amines has been mentioned in the literature, but there has been no systematic study of their influence on the rate of the condensation reaction of the alkoxide and the microstructure of the resultant gel.

  13. Beyond Spontaneously Broken Symmetry in Bose-Einstein Condensates

    SciTech Connect

    Mullin, W. J.; Laloee, F.

    2010-04-16

    Spontaneous symmetry breaking (SSB) for Bose-Einstein condensates cannot treat phase off-diagonal effects, and thus cannot explain Bell inequality violations. We describe another situation that is beyond a SSB treatment: an experiment where particles from two (possibly macroscopic) condensate sources are used for conjugate measurements of the relative phase and populations. Off-diagonal phase effects are characterized by a 'quantum angle' and observed via 'population oscillations', signaling quantum interference of macroscopically distinct states.

  14. Coupling a Bose condensate to micromechanical oscillators

    NASA Astrophysics Data System (ADS)

    Kemp, Chandler; Fox, Eli; Flanz, Scott; Vengalattore, Mukund

    2011-05-01

    We describe the construction of a compact apparatus to investigate the interaction of a spinor Bose-Einstein condensate and a micromechanical oscillator. The apparatus uses a double magneto-optical trap, Raman sideband cooling, and evaporative cooling to rapidly produce a 87Rb BEC in close proximity to a high Q membrane. The micromotion of the membrane results in small Zeeman shifts at the location of the BEC due to a magnetic domain attached to the oscillator. Detection of this micromotion by the condensate results in a backaction on the membrane. We investigate prospects of using this backaction to generate nonclassical states of the mechanical oscillator. This work was funded by the DARPA ORCHID program.

  15. Polarimeter Arrays with Comprehensive Frequency Coverage for the Next Generation of Precision Microwave Background Experiments

    NASA Astrophysics Data System (ADS)

    Austermann, Jason Edward; Beall, James; Becker, Dan; Cho, Hsiao-Mei; Duff, Shannon; gao, jiansong; Hilton, Gene; Hubmayr, Johannes; Irwin, Kent; li, dale; McKenney, Christopher; Ullom, Joel; van lanen, jeffrey; Vissers, Michael

    2016-06-01

    Spectral resolution at (sub-)millimeter wavelengths is now understood to be crucially important in precision measurements of the cosmic microwave background (CMB). Recent results from the Planck and BICEP/KECK experiments have established that measurements of the CMB polarization signal is limited, in part, by polarized foreground emission. In particular, polarized emission from galactic dust has been found to dominate and obscure potential signals of cosmic inflation, even in regions of the sky specifically identified as having relatively low galactic emission. Current and future experiments aim to address foreground contamination by conducting high-sensitivity observations with broad spectral coverage that will allow for differentiation within the measured signal between foreground sources of polarization and that of the CMB, which each have distinct spectral characteristics. To efficiently achieve these goals within a limited focal plane area, NIST-Boulder has developed multi-band TES-based polarimeters that simultaneously measure multiple spectral bands in each of two orthogonal polarizations. This acts to both increase pixel sensitivity through an increased total bandwidth, as well as providing broad spectral information for differentiation of emission sources. Here, we describe recent achievements and ongoing efforts at NIST-Boulder in the development of millimeter and sub-millimeter detector and focal plane technologies for future experiments, including the stage-IV CMB experiment, CMB-S4. NIST-Boulder provides critical cryogenic components to a large number of current and in-development CMB experiments. Recent milestones include the fielding of the first broadband multi-chroic mm-wave polarimeters in the ACTPol experiment, multi-band array fabrication on large-format 150 mm wafers, and development of matching 150 mm silicon platelet feedhorn arrays. We also review several related development efforts in detector, optical coupling, and readout technologies

  16. Item generation in the development of an inpatient experience questionnaire: a qualitative study

    PubMed Central

    2013-01-01

    Background Patient experience is a key feature of quality improvement in modern health-care delivery. Measuring patient experience is one of several tools used to assess and monitor the quality of health services. This study aims to develop a tool for assessing patient experience with inpatient care in public hospitals in Hong Kong. Methods Based on the General Inpatient Questionnaire (GIQ) framework of the Care Quality Commission as a discussion guide, a qualitative study involving focus group discussions and in-depth individual interviews with patients was employed to develop a tool for measuring inpatient experience in Hong Kong. Results All participants agreed that a patient satisfaction survey is an important platform for collecting patients’ views on improving the quality of health-care services. Findings of the focus group discussions and in-depth individual interviews identified nine key themes as important hospital quality indicators: prompt access, information provision, care and involvement in decision making, physical and emotional needs, coordination of care, respect and privacy, environment and facilities, handling of patient feedback, and overall care from health-care professionals and quality of care. Privacy, complaint mechanisms, patient involvement, and information provision were further highlighted as particularly important areas for item revision by the in-depth individual interviews. Thus, the initial version of the Hong Kong Inpatient Experience Questionnaire (HKIEQ), comprising 58 core items under nine themes, was developed. Conclusions A set of dimensions and core items of the HKIEQ was developed and the instrument will undergo validity and reliability tests through a validation survey. A valid and reliable tool is important in accurately assessing patient experience with care delivery in hospitals to improve the quality of health-care services. PMID:23835186

  17. On-site mirror facet condensation measurements for the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Dipold, J.; Medina, M. C.; García, B.; Rasztocky, E.; Mancilla, A.; Maya, J.; Larrarte, J. J.; de Souza, V.

    2016-09-01

    The Imaging Atmospheric Cherenkov Technique (IACT) has provided very important discoveries in Very High Energy (VHE) γ-ray astronomy for the last two decades, being exploited mainly by experiments such as H.E.S.S., MAGIC and VERITAS. The same technique will be used by the next generation of γ-ray telescopes, Cherenkov Telescope Array - CTA, which is conceived to be an Observatory composed by two arrays strategically placed in both hemispheres, one in the Northern and one in the Southern. Each site will consist of several tens of Cherenkov telescopes of different sizes and will be equipped with about 10000 m2 of reflective surface. Because of its large size, the reflector of a Cherenkov telescope is composed of many individual mirror facets. Cherenkov telescopes operate without any protective system from weather conditions therefore it is important to understand how the reflective surfaces behave under different environmental conditions. This paper describes a study of the behavior of the mirrors in the presence of water vapor condensation. The operational time of a telescope is reduced by the presence of condensation on the mirror surface, therefore, to control and to monitor the formation of condensation is an important issue for IACT observatories. We developed a method based on pictures of the mirrors to identify the areas with water vapor condensation. The method is presented here and we use it to estimate the time and area two mirrors had condensation when exposed to the environmental conditions in the Argentinean site. The study presented here shows important guidelines in the selection procedure of mirror technologies and shows an innovative monitoring tool to be used in future Cherenkov telescopes.

  18. APPARATUS FOR CONDENSATION AND SUBLIMATION

    DOEpatents

    Schmidt, R.J.; Fuis, F. Jr.

    1958-10-01

    An apparatus is presented for the sublimation and condensation of uranium compounds in order to obtain an improved crystalline structure of this material. The apparatus comprises a vaporizing chamber and condensing structure connected thereto. There condenser is fitted with a removable liner having a demountable baffle attached to the liner by means of brackets and a removable pin. The baffle is of spiral cross-section and is provided with cooling coils disposed between the surfaces of the baffle for circulation of a temperature controlling liquid within the baffle. The cooling coll provides for controlllng the temperature of the baffle to insure formatlon of a satisfactory condensate, and the removable liner facilitates the removal of condensate formed during tbe sublimation process.

  19. Modeling of rapid direct-contact condensation. Report on phase 1 (Final)

    SciTech Connect

    Wallis, G.B.; Richter, H.J.; Valenzuela, J.A.; Rothe, P.H.

    1985-08-01

    The focus of the study is on rapid direct-contact condensation phenomena, that is, direct-contact condensation situations characterized by extremely high condensation rates and violent mixing at the liquid-vapor interface. Rapid condensation phenomena arise in many industrial processes, but general methods do not presently exist to design effective components or to avoid system-flow instability. A conceptual model and preliminary analysis of rapid condensation are presented, and preliminary, proof-of-concept experiments are described. Some background information and a brief survey of previous work in the area are also provided.

  20. Model-data synthesis for the next generation of forest free-air CO2 enrichment (FACE) experiments.

    PubMed

    Norby, Richard J; De Kauwe, Martin G; Domingues, Tomas F; Duursma, Remko A; Ellsworth, David S; Goll, Daniel S; Lapola, David M; Luus, Kristina A; MacKenzie, A Rob; Medlyn, Belinda E; Pavlick, Ryan; Rammig, Anja; Smith, Benjamin; Thomas, Rick; Thonicke, Kirsten; Walker, Anthony P; Yang, Xiaojuan; Zaehle, Sönke

    2016-01-01

    The first generation of forest free-air CO2 enrichment (FACE) experiments has successfully provided deeper understanding about how forests respond to an increasing CO2 concentration in the atmosphere. Located in aggrading stands in the temperate zone, they have provided a strong foundation for testing critical assumptions in terrestrial biosphere models that are being used to project future interactions between forest productivity and the atmosphere, despite the limited inference space of these experiments with regards to the range of global ecosystems. Now, a new generation of FACE experiments in mature forests in different biomes and over a wide range of climate space and biodiversity will significantly expand the inference space. These new experiments are: EucFACE in a mature Eucalyptus stand on highly weathered soil in subtropical Australia; AmazonFACE in a highly diverse, primary rainforest in Brazil; BIFoR-FACE in a 150-yr-old deciduous woodland stand in central England; and SwedFACE proposed in a hemiboreal, Pinus sylvestris stand in Sweden. We now have a unique opportunity to initiate a model-data interaction as an integral part of experimental design and to address a set of cross-site science questions on topics including responses of mature forests; interactions with temperature, water stress, and phosphorus limitation; and the influence of biodiversity. PMID:26249015

  1. Early utility experience with wind power generation. Volume 3: Bonneville Power Administration Goodnoe Hills Project. Final report

    SciTech Connect

    McCabe, T.; Henry, G.; Tennis, M.; Goldenblatt, M.

    1984-01-01

    This report is one of three presenting the results of EPRI Research Project 1590-1, Evaluation of Electric Utility Experience with Wind Power Generation. The objective of this project was to develop an improved understanding of wind power generation, in particular the process a utility must undergo to initiate and carry out a wind turbine project. The primary tasks of RP1590-1 were to document and evaluate the experience of two utilities with megawatt-scale wind turbine installations from project inception to the wind turbine's first rotation. This technical report presents the experiences of the Bonneville Power Administration (BPA) as the participating utility in the MOD-2 cluster field test program. Under this program the National Aeronautics and Space Administration (NASA) as management agent for the US Department of Energy, has installed three MOD-2 wind turbines at Bonneville's Goodnoe Hills site. All documents and reports pertaining to BPA's experience with wind energy at Goodnoe Hills were reviewed and excerpts made of the highlights. Gaps in the documentation were filled by talking with the appropriate people. Site visits were conducted to monitor current activity. The information obtained was evaluated for its generic relevance and benefit to other utilities. The chronology of the steps taken in implementing the wind turbine project and some of the lessons learned are included in the report. In each section, important activities, critical assumptions, and interesting insights which might benefit other utility wind programs are identified.

  2. The Nature of Experiences Responsible for the Generation and Maintenance of Interest in STEM

    ERIC Educational Resources Information Center

    Maltese, Adam V.; Melki, Christina S.; Wiebke, Heidi L.

    2014-01-01

    Previous research has established the importance of early interest in STEM as a key factor in persistence. Our current research builds on this foundation and extends it to add more detail to understanding the types of experiences that trigger and maintain interest in science, technology, engineering, and mathematics (STEM). Using survey data from…

  3. The American Reincarnation of the Superfluous Experience: Finding Meaning in Generation Y

    ERIC Educational Resources Information Center

    Duffey, Madelyn Elizabeth

    2005-01-01

    The superfluous man became a prominent literary figure in Russia during the 19th century. This article makes a comparison of the superfluous experience to the "celebutante" phenomenon, as reflected in the media. It also includes a discussion on the impact that the celebutante influence may have on the dreams, values and meaning-making experience…

  4. Educating an "iPod" Generation: Undergraduate Attitudes, Experiences and Understanding of Vodcast and Podcast Use

    ERIC Educational Resources Information Center

    Parson, Vanessa; Reddy, Peter; Wood, Jon; Senior, Carl

    2009-01-01

    There is an increasing pressure on university staff to provide ever more information and resources to students. This study investigated student opinions on (audio) podcasts and (video) vodcasts and how well they met requirements and aided learning processes. Two experiments within the Aston University looked at student opinion on, and usage of,…

  5. Learning a Generative Probabilistic Grammar of Experience: A Process-Level Model of Language Acquisition

    ERIC Educational Resources Information Center

    Kolodny, Oren; Lotem, Arnon; Edelman, Shimon

    2015-01-01

    We introduce a set of biologically and computationally motivated design choices for modeling the learning of language, or of other types of sequential, hierarchically structured experience and behavior, and describe an implemented system that conforms to these choices and is capable of unsupervised learning from raw natural-language corpora. Given…

  6. The convergence of theory and experiment in direct combustion generated noise

    NASA Technical Reports Server (NTRS)

    Strahle, W. C.

    1975-01-01

    Current theories of combustion generated noise are reviewed with regard to their ability to predict the sound power output and spectral characteristics of noise generated by several flame types. New experimental information on open turbulent flames and on gas turbine combustor cans is presented. Available information on gas phase diffusion flames is reviewed. It is concluded that if some of the gross turbulence features of the flame are known and if the acoustical behavior of any flame enclosure is known, then scaling rules for behavior of the sound power output and spectral content may be quite accurately produced by theory. On the other hand, the theory is not sufficiently advanced to make absolute predictions; such predictions must await more detailed knowledge of turbulent flame structure.

  7. Generation of large scale field-aligned density irregularities in ionospheric heating experiments. [electromagnetic wave decay

    NASA Technical Reports Server (NTRS)

    Fejer, J. A.

    1974-01-01

    Threshold and growth rate for stimulated Brillouin scattering are calculated for a uniform magnetoplasma. These are then compared with the threshold and growth rate of a new thermal instability in which the nonlinear Lorentz force felt by the electrons at the beat frequency of the two electromagnetic waves is replaced by a pressure force due to differential heating in the interference pattern of the pump wave and the generated electromagnetic wave. This thermal instability, which is still essentially stimulated Brillouin scattering, has a threshold which is especially low when the propagation vector of the beat wave is almost normal to the magnetic field. The threshold is then considerably lower than the threshold for normal stimulated Brillouin scattering and therefore this new instability is probably responsible for the generation of large scale field aligned irregularities and ionospheric spread F.

  8. Lost Origins of the Third Generation of Quarks: Theory, Philosophy, and Experiment

    NASA Astrophysics Data System (ADS)

    Staley, Kent W.

    Physicists generally attribute the introduction of a third generation of quarks (the ``top'' and ``bottom'' quarks) into the standard model of the elementary particles to a 1973 paper by Makoto Kobayashi and Toshihide Maskawa. I describe the historical background to that paper, emphasizing the largely forgotten role of theorists at Nagoya University and the ``Nagoya model'' they developed. Several of the authors of the Nagoya model embraced the philosophy of dialectical materialism, and I discuss the role that such metaphysical commitments play in physical theorizing. Both theoretical and experimental developments that generated great interest in Japan, and ultimately stimulated Kobayashi and Maskawa's 1973 work, went almost entirely unnoticed in the U.S. The episode exemplifies both the importance of untestable ``themata'' in developing new theories, and the difficulties that may arise when two parts of a research community work in relative isolation from one another.

  9. Meeting the Next Generation Science Standards Through "Rediscovered" Climate Model Experiments

    NASA Astrophysics Data System (ADS)

    Sohl, L. E.; Chandler, M. A.; Zhou, J.

    2013-12-01

    Since the Educational Global Climate Model (EdGCM) Project made its debut in January 2005, over 150 institutions have employed EdGCM software for a variety of uses ranging from short lab exercises to semester-long and year-long thesis projects. The vast majority of these EdGCM adoptees have been at the undergraduate and graduate levels, with few users at the K-12 level. The K-12 instructors who have worked with EdGCM in professional development settings have commented that, although EdGCM can be used to illustrate a number of the Disciplinary Core Ideas and connects to many of the Common Core State Standards across subjects and grade levels, significant hurdles preclude easy integration of EdGCM into their curricula. Time constraints, a scarcity of curriculum materials, and classroom technology are often mentioned as obstacles in providing experiences to younger grade levels in realistic climate modeling research. Given that the NGSS incorporates student performance expectations relating to Earth System Science, and to climate science and the human dimension in particular, we feel that a streamlined version of EdGCM -- one that eliminates the need to run the climate model on limited computing resources, and provides a more guided climate modeling experience -- would be highly beneficial for the K-12 community. This new tool currently under development, called EzGCM, functions through a browser interface, and presents "rediscovery experiments" that allow students to do their own exploration of model output from published climate experiments, or from sensitivity experiments designed to illustrate how climate models as well as the climate system work. The experiments include background information and sample questions, with more extensive notes for instructors so that the instructors can design their own reflection questions or follow-on activities relating to physical or human impacts, as they choose. An added benefit of the EzGCM tool is that, like EdGCM, it helps

  10. Recurrent filmwise and dropwise condensation on a beetle mimetic surface.

    PubMed

    Hou, Youmin; Yu, Miao; Chen, Xuemei; Wang, Zuankai; Yao, Shuhuai

    2015-01-27

    Vapor condensation plays a key role in a wide range of industrial applications including power generation, thermal management, water harvesting and desalination. Fast droplet nucleation and efficient droplet departure as well as low interfacial thermal resistance are important factors that determine the thermal performances of condensation; however, these properties have conflicting requirements on the structural roughness and surface chemistry of the condensing surface or condensation modes (e.g., filmwise vs dropwise). Despite intensive efforts over the past few decades, almost all studies have focused on the dropwise condensation enabled by superhydrophobic surfaces. In this work, we report the development of a bioinspired hybrid surface with high wetting contrast that allows for seamless integration of filmwise and dropwise condensation modes. We show that the synergistic cooperation in the observed recurrent condensation modes leads to improvements in all aspects of heat transfer properties including droplet nucleation density, growth rate, and self-removal, as well as overall heat transfer coefficient. Moreover, we propose an analytical model to optimize the surface morphological features for dramatic heat transfer enhancement. PMID:25482594

  11. Role of spatial anisotropy in design storm generation: Experiment and interpretation

    NASA Astrophysics Data System (ADS)

    Niemi, Tero J.; Guillaume, Joseph H. A.; Kokkonen, Teemu; Hoang, Tam M. T.; Seed, Alan W.

    2016-01-01

    Rainfall accumulation depths over a given area are strongly dependent on the shape of the storm together with its direction of advection. A method to produce design storms exhibiting anisotropic spatial scaling is presented by combining a state-of-the-art stochastic rainfall generator STEPS with the linear generalized scale invariance (GSI) notation. The enhanced model is used to create ensembles of design storms based on an extreme storm with a distinct rainband shape observed in Melbourne, Australia. Design storms are generated both with and without accounting for anisotropy. Effect of anisotropy on precipitation characteristics is studied using the entire region covered by the radar (radar scale) and at a significantly smaller catchment scale. A rainfall-runoff model is applied to route the rainfall through the catchment into streamflow. Accounting for anisotropy allows for a more realistic description of precipitation features at the radar scale. At the catchment scale, anisotropy increases the probability of high rainfall accumulations, which translates into greater flood volumes. No discernible difference was observed in streamflow characteristics after controlling for the accumulation over the catchment. This could be explained by a lower importance of anisotropy relative to other factors affecting streamflow generation, and by the difficulties in creating representative rainfall temporal properties at the catchment scale when the radar scale is used for model calibration. The proposed method provides a tool to create ensembles of design storms when the anisotropic shape of the fields is of importance.

  12. Extraction of correlated count rates using various gate generation techniques: Part II Experiment

    NASA Astrophysics Data System (ADS)

    Henzlova, D.; Croft, S.; Menlove, H. O.; Swinhoe, M. T.

    2012-11-01

    This paper presents an experimental comparison of different neutron pulse train analysis methods developed to extract correlated count rates from the detected neutron arrival times. This work comprises a sequel to the previous paper (Part I Theory) [1], where the complete formalism of different analysis methods was presented. In the current paper, the signal triggered inspection (STI), randomly triggered inspection (RTI) and MIXED techniques (implemented in current shift register hardware) are compared using list mode data acquired from series of 252Cf sources. In addition, three techniques of randomly triggered inspection are investigated: gates generated at fixed clock frequency, i.e., consecutive (non-overlapping) gates and overlapping gates (known as fast accidentals sampling (FAS)), as well as gates generated after a long delay following each trigger pulse (delayed-signal gates). The average correlated count rates (singles (S), doubles (D) and triples (T)) are extracted using the STI, RTI and MIXED analysis techniques and compared to demonstrate their equivalence. In addition, an influence of different gate generation and pulse train analysis techniques on the precision of the measured S, D and T rates is investigated.

  13. High Frequency Resolution TOA Analysis for ELF/VLFWave Generation Experiments at HAARP

    NASA Astrophysics Data System (ADS)

    Ruddle, J. D.; Moore, R. C.

    2014-12-01

    Modulated HF heating of the ionosphere in the presence of natural ionospheric current sources has been used as a method to generate electromagnetic ELF/VLF waves since the 1970's. In the ~1-5 kHz band, the amplitude and phase of the received ELF/VLF signal depends on the amplitude and phase of the conductivity modulation generated throughout the HF-heated ionospheric body, as well as on the signal propagation parameters (i.e., the attenuation and phase constants) between each of the current sources and the receiver. Recent signal processing advances have produced an accurate ELF/VLF time-of-arrival (TOA) analysis technique that differentiates line-of-sight and ionospherically-reflected signal components, determining the amplitude and phase of each component observed at the receiver. This TOA method requires a wide bandwidth (> 2.5 kHz) and therefore is relatively insensitive to the frequency-dependent nature of ELF/VLF wave propagation. In this paper, we present an improved ELF/VLF TOA method that is capable of providing high frequency resolution. The new analysis technique is applied to experimental observations of ELF/VLF signals generated by modulated heating at HAARP. We present measurements of the amplitude and phase of the received ELF/VLF signal as a function of frequency and compare the results with the predictions of an HF heating model.

  14. Operating experience of the EBR-II intermediate heat exchanger and the steam generator system

    SciTech Connect

    Buschman, H.W.; Longua, K.J.; Penney, W.H.

    1983-01-01

    Experimental Breeder Reactor-II (EBR-II) is an experimental liquid metal fast breeder reactor located at the Idaho National Engineering Laboratory. It consists of an unmoderated, heterogeneous, sodium-cooled reactor with a nominal thermal power output of 62.5 MW; an intermediate closed loop of secondary sodium coolant; and a steam plant that produces 20 MW of electrical power through a conventional turbine generator. The EBR-II heat transport system continues to operate satisfactorily after 18 years. This represents about 89,000 hours of steaming, which results in a total integrated thermal power production of about 215,000 MWd. In this time, the steam generator has experienced over 580 plant startups and 349 reactor scrams. The plant capacity factor for the past five years has been in excess of 70%, and in fact has averaged almost 60% over the last thirteen years. This excellent record is partly attributable to the trouble-free operation of the steam generator which, aside from an initial construction tube-to-tubesheet weld defect, has had a plant availability of 100%.

  15. Modeling of Bulk Evaporation and Condensation

    NASA Technical Reports Server (NTRS)

    Anghaie, S.; Ding, Z.

    1996-01-01

    This report describes the modeling and mathematical formulation of the bulk evaporation and condensation involved in liquid-vapor phase change processes. An internal energy formulation, for these phase change processes that occur under the constraint of constant volume, was studied. Compared to the enthalpy formulation, the internal energy formulation has a more concise and compact form. The velocity and time scales of the interface movement were obtained through scaling analysis and verified by performing detailed numerical experiments. The convection effect induced by the density change was analyzed and found to be negligible compared to the conduction effect. Two iterative methods for updating the value of the vapor phase fraction, the energy based (E-based) and temperature based (T-based) methods, were investigated. Numerical experiments revealed that for the evaporation and condensation problems the E-based method is superior to the T-based method in terms of computational efficiency. The internal energy formulation and the E-based method were used to compute the bulk evaporation and condensation processes under different conditions. The evolution of the phase change processes was investigated. This work provided a basis for the modeling of thermal performance of multi-phase nuclear fuel elements under variable gravity conditions, in which the buoyancy convection due to gravity effects and internal heating are involved.

  16. Condenser performance recovery in nuclear power plants

    SciTech Connect

    Saxon, G. Jr.; Putman, R.E.

    1996-12-31

    Fouling of the tubes in the main condenser can have a significant impact on nuclear plant performance. Recent experiences suggest that the effects of fouling have been underestimated and that the results of an effective tube cleaning can be measured in improved unit capacity. In particular two nuclear power plants have reported recovery of 20 and 25 MW respectively. While the types of deposition often vary as they did in these two cases, the deposit elements were accurately identified, the deposits` impact on heat transfer was evaluated and an effective cleaning methodology was developed for successful deposit removal. These experiences have prompted the development of a number of diagnostic monitoring and inspection methods which can be utilized in the field or in the laboratory; to detect, identify and quantify the presence of fouling and its impact on heat transfer, to determine the relative effectiveness of a cleaning method and to evaluate condenser performance as related to MW capacity for both single and multiple compartment condensers.

  17. Experimental evidence of condensation-driven airflow

    NASA Astrophysics Data System (ADS)

    Bunyard, P.; Hodnett, M.; Poveda, G.; Burgos Salcedo, J. D.; Peña, C.

    2015-10-01

    The dominant "convection" model of atmospheric circulation is based on the premise that hot air expands and rises, to be replaced by colder air, thereby creating horizontal surface winds. A recent theory put forward by Makarieva and Gorshkov (2007, 2013) maintains that the primary motive force of atmospheric circulation derives from the intense condensation and sharp pressure reduction that is associated with regions where a high rate of evapotranspiration from natural closed-canopy forests provides the "fuel" for cloud formation. The net result of the "biotic pump" theory is that moist air flows from ocean to land, drawn in by the pressure changes associated with a high rate of condensation. To test the physics underpinning the biotic pump theory, namely that condensation of water vapour, at a sufficiently high rate, results in an uni-directional airflow, a 5 m tall experimental apparatus was designed and built, in which a 20 m3 body of atmospheric air is enclosed inside an annular 14 m long space (a "square donut") around which it can circulate freely, allowing for rotary air flows. One vertical side of the apparatus contains some 17 m of copper refrigeration coils, which cause condensation. The apparatus contains a series of sensors measuring temperature, humidity and barometric pressure every five seconds, and air flow every second. The laws of Newtonian physics are used in calculating the rate of condensation inside the apparatus. The results of more than one hundred experiments show a highly significant correlation, with r2 > 0.9, of airflow and the rate of condensation. The rotary air flows created appear to be consistent both in direction and velocity with the biotic pump hypothesis, the critical factor being the rate change in the partial pressure of water vapour in the enclosed body of atmospheric air. Air density changes, in terms of kinetic energy, are found to be orders of magnitude smaller than the kinetic energy of partial pressure change. The

  18. Supermode-polariton condensation in a multimode cavity QED-BEC system

    NASA Astrophysics Data System (ADS)

    Vaidya, Varun; Kollar, Alicia; Papageorge, Alexander; Guo, Yudan; Lev, Benjamin

    2016-05-01

    Investigations of many-body physics in an AMO context often employ a static optical lattice to create a periodic potential. Such systems, while capable of exploring, e.g., the Hubbard model, lack the fully emergent crystalline order found in solid state systems whose stiffness is not imposed externally, but arises dynamically. Our multimode cavity QED experiment is introducing a new method of generating fully emergent and compliant optical lattices to the ultracold atom toolbox and provides new avenues to explore quantum liquid crystalline order. We will present our first experimental result, the first observation of a supermode-polariton condensate via a supermode superradiant phase transition.

  19. Noble gas trapping by laboratory carbon condensates

    NASA Technical Reports Server (NTRS)

    Niemeyer, S.; Marti, K.

    1982-01-01

    Trapping of noble gases by carbon-rich matter was investigated by synthesizing carbon condensates in a noble gas atmosphere. Laser evaporation of a solid carbon target yielded submicron grains which proved to be efficient noble gas trappers (Xe distribution coefficients up to 13 cu cm STP/g-atm). The carbon condensates are better noble gas trappers than previously reported synthetic samples, except one, but coefficients inferred for meteoritic acid-residues are still orders of magnitude higher. The trapped noble gases are loosely bound and elementally strongly fractionated, but isotopic fractionations were not detected. Although this experiment does not simulate nebular conditions, the results support the evidence that carbon-rich phases in meteorites may be carriers of noble gases from early solar system reservoirs. The trapped elemental noble gas fractionations are remarkably similar to both those inferred for meteorites and those of planetary atmospheres for earth, Mars and Venus.

  20. Transonic flow past an airfoil with condensation

    NASA Technical Reports Server (NTRS)

    Schmidt, B.

    1978-01-01

    In connection with investigations conducted to determine the influence of water vapor on experiments in wind tunnels, the question arose as to what changes due to vapor condensation might be expected in airfoil measurements. Density measurements on circular-arc airfoils aided by an interferometer in choked tunnels with parallel walls show that increasing humidity produces increasing changes in the flow field. The flow becomes nonstationary at high humidity. At the airfoil, however, the influence of the condensation is only felt, inasmuch as the shock bounding the local supersonic region moves upstream with increasing humidity while its intensity decreases. The density distribution upstream of the shock remains unchanged. Even if the flow becomes nonstationary in the vicinity of the airfoil, no changes occur at the airfoil.