Sample records for atmospheric phenomena

  1. Twilight phenomena in the atmosphere of Venus during the 2004 inferior conjunction

    E-print Network

    Schneider, Glenn

    Twilight phenomena in the atmosphere of Venus during the 2004 inferior conjunction Paolo Tanga Laboratoire Cassiopée - Observatoire de la Côte d'Azur #12;Twilight phenomena in the atmosphere of Venus'Azur Abstract - Twilight phenomena of Venus are peculiar aspects visible in proximity of the inferior

  2. Dynamics of pulse phenomena in helium dielectric-barrier atmospheric-pressure glow discharges

    E-print Network

    Raja, Laxminarayan L.

    Dynamics of pulse phenomena in helium dielectric-barrier atmospheric-pressure glow discharges of pulse phenomena in conventional parallel-plate dielectric-barrier controlled atmospheric-pressure glow. DOI: 10.1063/1.1625414 I. INTRODUCTION There is rapidly growing interest in atmospheric- pressure glow

  3. Effects of oceanic and atmospheric phenomena on precipitation and flooding in the Manafwa River Basin

    E-print Network

    Finney, William W., III (William Warner)

    2014-01-01

    An investigation was performed to determine the relationship between certain oceanic and atmospheric phenomena and the precipitation patterns in the Manafwa River Basin of eastern Uganda. Such phenomena are the El Niño ...

  4. Science of atmospheric phenomena with JEM-EUSO

    NASA Astrophysics Data System (ADS)

    Adams, J. H.; Ahmad, S.; Albert, J.-N.; Allard, D.; Anchordoqui, L.; Andreev, V.; Anzalone, A.; Arai, Y.; Asano, K.; Ave Pernas, M.; Baragatti, P.; Barrillon, P.; Batsch, T.; Bayer, J.; Bechini, R.; Belenguer, T.; Bellotti, R.; Belov, K.; Berlind, A. A.; Bertaina, M.; Biermann, P. L.; Biktemerova, S.; Blaksley, C.; Blanc, N.; B??cki, J.; Blin-Bondil, S.; Blümer, J.; Bobik, P.; Bogomilov, M.; Bonamente, M.; Briggs, M. S.; Briz, S.; Bruno, A.; Cafagna, F.; Campana, D.; Capdevielle, J.-N.; Caruso, R.; Casolino, M.; Cassardo, C.; Castellinic, G.; Catalano, C.; Catalano, G.; Cellino, A.; Chikawa, M.; Christl, M. J.; Cline, D.; Connaughton, V.; Conti, L.; Cordero, G.; Crawford, H. J.; Cremonini, R.; Csorna, S.; Dagoret-Campagne, S.; de Castro, A. J.; De Donato, C.; de la Taille, C.; De Santis, C.; del Peral, L.; Dell'Oro, A.; De Simone, N.; Di Martino, M.; Distratis, G.; Dulucq, F.; Dupieux, M.; Ebersoldt, A.; Ebisuzaki, T.; Engel, R.; Falk, S.; Fang, K.; Fenu, F.; Fernández-Gómez, I.; Ferrarese, S.; Finco, D.; Flamini, M.; Fornaro, C.; Franceschi, A.; Fujimoto, J.; Fukushima, M.; Galeotti, P.; Garipov, G.; Geary, J.; Gelmini, G.; Giraudo, G.; Gonchar, M.; González Alvarado, C.; Gorodetzky, P.; Guarino, F.; Guzmán, A.; Hachisu, Y.; Harlov, B.; Haungs, A.; Hernández Carretero, J.; Higashide, K.; Ikeda, D.; Ikeda, H.; Inoue, N.; Inoue, S.; Insolia, A.; Isgrò, F.; Itow, Y.; Joven, E.; Judd, E. G.; Jung, A.; Kajino, F.; Kajino, T.; Kaneko, I.; Karadzhov, Y.; Karczmarczyk, J.; Karus, M.; Katahira, K.; Kawai, K.; Kawasaki, Y.; Keilhauer, B.; Khrenov, B. A.; Kim, J.-S.; Kim, S.-W.; Kim, S.-W.; Kleifges, M.; Klimov, P. A.; Kolev, D.; Kreykenbohm, I.; Kudela, K.; Kurihara, Y.; Kusenko, A.; Kuznetsov, E.; Lacombe, M.; Lachaud, C.; Lee, J.; Licandro, J.; Lim, H.; López, F.; Maccarone, M. C.; Mannheim, K.; Maravilla, D.; Marcelli, L.; Marini, A.; Martinez, O.; Masciantonio, G.; Mase, K.; Matev, R.; Medina-Tanco, G.; Mernik, T.; Miyamoto, H.; Miyazaki, Y.; Mizumoto, Y.; Modestino, G.; Monaco, A.; Monnier-Ragaigne, D.; Morales de los Ríos, J. A.; Moretto, C.; Morozenko, V. S.; Mot, B.; Murakami, T.; Murakami, M. Nagano; Nagata, M.; Nagataki, S.; Nakamura, T.; Napolitano, T.; Naumov, D.; Nava, R.; Neronov, A.; Nomoto, K.; Nonaka, T.; Ogawa, T.; Ogio, S.; Ohmori, H.; Olinto, A. V.; Orlea?ski, P.; Osteria, G.; Panasyuk, M. I.; Parizot, E.; Park, I. H.; Park, H. W.; Pastircak, B.; Patzak, T.; Paul, T.; Pennypacker, C.; Perez Cano, S.; Peter, T.; Picozza, P.; Pierog, T.; Piotrowski, L. W.; Piraino, S.; Plebaniak, Z.; Pollini, A.; Prat, P.; Prévôt, G.; Prieto, H.; Putis, M.; Reardon, P.; Reyes, M.; Ricci, M.; Rodríguez, I.; Rodríguez Frías, M. D.; Ronga, F.; Roth, M.; Rothkaehl, H.; Roudil, G.; Rusinov, I.; Rybczy?ski, M.; Sabau, M. D.; Sáez-Cano, G.; Sagawa, H.; Saito, A.; Sakaki, N.; Sakata, M.; Salazar, H.; Sánchez, S.; Santangelo, A.; Santiago Crúz, L.; Sanz Palomino, M.; Saprykin, O.; Sarazin, F.; Sato, H.; Sato, M.; Schanz, T.; Schieler, H.; Scotti, V.; Segreto, A.; Selmane, S.; Semikoz, D.; Serra, M.; Sharakin, S.; Shibata, T.; Shimizu, H. M.; Shinozaki, K.; Shirahama, T.; Siemieniec-Ozi?b?o, G.; Silva López, H. H.; Sledd, J.; S?omi?ska, K.; Sobey, A.; Sugiyama, T.; Supanitsky, D.; Suzuki, M.; Szabelska, B.; Szabelski, J.; Tajima, F.; Tajima, N.; Tajima, T.; Takahashi, Y.; Takami, H.; Takeda, M.; Takizawa, Y.; Tenzer, C.; Tibolla, O.; Tkachev, L.; Tokuno, H.; Tomida, T.; Tone, N.; Toscano, S.; Trillaud, F.; Tsenov, R.; Tsunesada, Y.; Tsuno, K.; Tymieniecka, T.; Uchihori, Y.; Unger, M.; Vaduvescu, O.; Valdés-Galicia, J. F.; Vallania, P.; Valore, L.; Vankova, G.; Vigorito, C.; Villaseñor, L.; von Ballmoos, P.; Wada, S.; Watanabe, J.; Watanabe, S.; Watts, J.; Weber, M.; Weiler, T. J.; Wibig, T.; Wiencke, L.; Wille, M.; Wilms, J.; W?odarczyk, Z.; Yamamoto, T.; Yamamoto, Y.; Yang, J.; Yano, H.; Yashin, I. V.; Yonetoku, D.; Yoshida, K.; Yoshida, S.; Young, R.; Zotov, M. Yu.; Zuccaro Marchi, A.; S?omi?ski, J.

    2015-07-01

    The main goal of the JEM-EUSO experiment is the study of Ultra High Energy Cosmic Rays (UHECR, 1019-1021 e V), but the method which will be used (detection of the secondary light emissions induced by cosmic rays in the atmosphere) allows to study other luminous phenomena. The UHECRs will be detected through the measurement of the emission in the range between 290 and 430 m, where some part of Transient Luminous Events (TLEs) emission also appears. This work discusses the possibility of using the JEM-EUSO Telescope to get new scientific results on TLEs. The high time resolution of this instrument allows to observe the evolution of TLEs with great precision just at the moment of their origin. The paper consists of four parts: review of the present knowledge on the TLE, presentation of the results of the simulations of the TLE images in the JEM-EUSO telescope, results of the Russian experiment Tatiana-2 and discussion of the possible progress achievable in this field with JEM-EUSO as well as possible cooperation with other space projects devoted to the study of TLE - TARANIS and ASIM. In atmospheric physics, the study of TLEs became one of the main physical subjects of interest after their discovery in 1989. In the years 1992 - 1994 detection was performed from satellite, aircraft and space shuttle and recently from the International Space Station. These events have short duration (milliseconds) and small scales (km to tens of km) and appear at altitudes 50 - 100 km. Their nature is still not clear and each new experimental data can be useful for a better understanding of these mysterious phenomena.

  5. A Review of Arcing Phenomena in Vacuum and in the Transition to Atmospheric Pressure Arcs

    Microsoft Academic Search

    C. W. Kimblin

    1982-01-01

    This paper reviews vacuum-arc phenomena, and the effect of low-pressure gaseous ambients on electrode phenomena in the transition to atmospheric pressure arcs. The 5 main areas addressed are cathode-spot phenomena, anode-spot phenomena, the properties of the interelectrode plasma for both diffuse arcs and columnar arcs, the interaction of vacuum arcs with axial and transverse magnetic fields, and finally, the transition

  6. Simulations of atmospheric phenomena at the Phoenix landing site with the Ames General Circulation Model

    Microsoft Academic Search

    Steven M. Nelli; Nilton O. Renno; James R. Murphy; William C. Feldman; Stephen W. Bougher

    2010-01-01

    Phoenix, the first NASA Mars Scout class mission, was designed to ``follow the water'' and study the polar region. Landing in late northern spring, Phoenix measured soil chemistry, near-surface water ice, and studied numerous atmospheric properties and weather phenomena. Here, we use atmospheric measurements made by Phoenix to test and calibrate the Ames General Circulation Model (GCM) and start the

  7. Simulations of atmospheric phenomena at the Phoenix landing site with the Ames General Circulation Model

    Microsoft Academic Search

    Steven M. Nelli; Nilton O. Renno; James R. Murphy; William C. Feldman; Stephen W. Bougher

    2010-01-01

    Phoenix, the first NASA Mars Scout class mission, was designed to “follow the water” and study the polar region. Landing in late northern spring, Phoenix measured soil chemistry, near-surface water ice, and studied numerous atmospheric properties and weather phenomena. Here, we use atmospheric measurements made by Phoenix to test and calibrate the Ames General Circulation Model (GCM) and start the

  8. Double streamer phenomena in atmospheric pressure low frequency corona plasma

    SciTech Connect

    Kim, Dan Bee; Jung, H.; Gweon, B.; Choe, Wonho [Department of Physics, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2010-07-15

    Time-resolved images of an atmospheric pressure corona discharge, generated at 50 kHz in a single pin electrode source, show unique positive and negative corona discharge features: a streamer for the positive period and a glow for the negative period. However, unlike in previous reports of dc pulse and low frequency corona discharges, multistreamers were observed at the initial time stage of the positive corona. A possible physical mechanism for the multistreamers is suggested.

  9. Phenomena of oscillations in atmospheric pressure direct current glow discharges

    SciTech Connect

    Liu, Fu-cheng [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)] [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Yan, Wen; Wang, De-zhen [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)] [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2013-12-15

    Self-sustained oscillations in a dc glow discharge with a semiconductor layer at atmospheric pressure were investigated by means of a one-dimensional fluid model. It is found that the dc glow discharge initially becomes unstable in the subnormal glow region and gives rise to oscillations of plasma parameters. A variety of oscillations with one or more frequencies have been observed under different conditions. The discharge oscillates between the glow discharge mode and the Townsend discharge mode in the oscillations with large amplitude while operates in the subnormal glow discharge mode all the while in the oscillations with small amplitude. Fourier Transform spectra of oscillations reveal the transition mechanism between different oscillations. The effects of semiconductor conductivity on the oscillation frequency of the dominant mode, gas voltage, as well as the discharge current have also been analyzed.

  10. A Study of the Effects of Atmospheric Phenomena on Mars Science Laboratory Entry Performance

    NASA Technical Reports Server (NTRS)

    Cianciolo, Alicia D.; Way, David W.; Powell, Richard W.

    2008-01-01

    At Earth during entry the shuttle has experienced what has come to be known as potholes in the sky or regions of the atmosphere where the density changes suddenly. Because of the small data set of atmospheric information where the Mars Science Laboratory (MSL) parachute deploys, the purpose of this study is to examine the effect similar atmospheric pothole characteristics, should they exist at Mars, would have on MSL entry performance. The study considers the sensitivity of entry design metrics, including altitude and range error at parachute deploy and propellant use, to pothole like density and wind phenomena.

  11. A numerical weather prediction system designed to simulate atmospheric downburst phenomena

    NASA Technical Reports Server (NTRS)

    Chuang, S.; Proctor, F. H.; Zack, J. W.; Kaplan, M. L.

    1984-01-01

    It is pointed out that an increase in the understanding of weather-related aircraft accidents can save hundreds of human lives and million of dollars. A better understanding regarding the interaction between aircraft operation and severe weather conditions can be obtained with the aid of flight simulator facilities. It is shown that numerical weather modeling is one of the most precise and cost-effective inputs for flight simulators in the long run. A comprehensive weather modeling system is being developed for the simulation of different scales of atmospheric phenomena. The modeling system utilizes two numerical weather models, including the Mesoscale Atmospheric Simulation system, and the Terminal Area Simulation System.

  12. Winter weather in Japan controlled by large-scale atmospheric and small-scale oceanic phenomena

    NASA Astrophysics Data System (ADS)

    Ando, Y.; Ogi, M.; Tachibana, Y.; Kodera, K.; Yamazaki, K.

    2014-12-01

    The important components of atmospheric circulation in the winter over the Northern Hemisphere are the Arctic Oscillation (AO) and Western Pacific (WP) pattern. Although in general negative AO and WP phases cause Siberia, East Asia, and Japan to be abnormally cold, Japan was relatively warm in October 2012 even though both the AO and WP were strongly negative. The temperature of the Sea of Japan reached a high in October 2012, and it was found that heating by these very warm waters, despite the small size of the Sea of Japan, overwhelmed the cooling effect of the strongly negative AO and WP in October. Linear regression analyses except the forcing of atmospheric circulations showed that Japan tends to be warm in years when the Sea of Japan is warm. Consequently, the temperature over Japan is statistically controlled by interannual variations of small-scale oceanic phenomena as well as by large-scale atmospheric patterns. Previous studies have ignored such small-scale oceanic influences on island temperatures.

  13. Determination of constant-volume balloon capabilities for aeronautical research. [specifically measurement of atmospheric phenomena

    NASA Technical Reports Server (NTRS)

    Tatom, F. B.; King, R. L.

    1977-01-01

    The proper application of constant-volume balloons (CVB) for measurement of atmospheric phenomena was determined. And with the proper interpretation of the resulting data. A literature survey covering 176 references is included. the governing equations describing the three-dimensional motion of a CVB immersed in a flow field are developed. The flowfield model is periodic, three-dimensional, and nonhomogeneous, with mean translational motion. The balloon motion and flow field equations are cast into dimensionless form for greater generality, and certain significant dimensionless groups are identified. An alternate treatment of the balloon motion, based on first-order perturbation analysis, is also presented. A description of the digital computer program, BALLOON, used for numerically integrating the governing equations is provided.

  14. A new South American network to study the atmospheric electric field and its variations related to geophysical phenomena

    NASA Astrophysics Data System (ADS)

    Tacza, J.; Raulin, J.-P.; Macotela, E.; Norabuena, E.; Fernandez, G.; Correia, E.; Rycroft, M. J.; Harrison, R. G.

    2014-12-01

    In this paper we present the capability of a new network of field mill sensors to monitor the atmospheric electric field at various locations in South America; we also show some early results. The main objective of the new network is to obtain the characteristic Universal Time diurnal curve of the atmospheric electric field in fair weather, known as the Carnegie curve. The Carnegie curve is closely related to the current sources flowing in the Global Atmospheric Electric Circuit so that another goal is the study of this relationship on various time scales (transient/monthly/seasonal/annual). Also, by operating this new network, we may also study departures of the Carnegie curve from its long term average value related to various solar, geophysical and atmospheric phenomena such as the solar cycle, solar flares and energetic charged particles, galactic cosmic rays, seismic activity and specific meteorological events. We then expect to have a better understanding of the influence of these phenomena on the Global Atmospheric Electric Circuit and its time-varying behavior.

  15. On recently studied possible atmospheric and ionospheric earthquake precursors and proposed physical mechanisms causing these phenomena

    Microsoft Academic Search

    C.-V. Meister; D. H. H. Hoffmann; V. A. Liperovsky; E. V. Liperovskaya

    2010-01-01

    About 20 years ago, a massive search for new, atmospheric and ionospheric precursors of earthquakes began. The aim was to improve the shorttime prediction of earthquakes, which seemed to be impossible using only traditional methods of prediction. Meanwhile, one knows a dozen of new presursors. One investigates thermodynamic parameters of the atmosphere, for instance temperature profiles and humidity, one studies

  16. HST imaging of atmospheric phenomena created by the impact of comet Shoemaker-Levy 9.

    PubMed

    Hammel, H B; Beebe, R F; Ingersoll, A P; Orton, G S; Mills, J R; Simon, A A; Chodas, P; Clarke, J T; De Jong, E; Dowling, T E

    1995-03-01

    Hubble Space Telescope (HST) images reveal major atmospheric changes created by the collision of comet Shoemaker-Levy 9 with Jupiter. Plumes rose to 3000 kilometers with ejection velocities on the order of 10 kilometers second-1; some plumes were visible in the shadow of Jupiter before rising into sunlight. During some impacts, the incoming bolide may have been detected. Impact times were on average about 8 minutes later than predicted. Atmospheric waves were seen with a wave front speed of 454 +/- 20 meters second-1. The HST images reveal impact site evolution and record the overall change in Jupiter's appearance as a result of the bombardment. PMID:7871425

  17. The role of critical velocity ionization phenomena in the atmosphere of Io

    Microsoft Academic Search

    Prasad C. Debi

    1995-01-01

    The Alfvén's critical ionization velocity (CIV) have been observed in a number of laboratory and space experiments. In the Io-torus system, relative velocity of the plasma species in the torus with respect to the neutral species in the Io's atmosphere and neutral cloud exceeds the critical velocity required for CIV. Townsand condition is satisfied up to 6rio, in the neutral

  18. The role of critical velocity ionization phenomena in the atmosphere of Io

    Microsoft Academic Search

    Prasad C. Debi

    1995-01-01

    The Alfvén's critical ionization velocity (CIV) have been observed in a number of laboratory and space experiments. In the Io-torus system, relative velocity of the plasma species in the torus with respect to the neutral species in the Io's atmosphere and neutral cloud exceeds the critical velocity required for CIV. Townsand condition is satisfied up to 6r io , in

  19. Modeling of asymmetric pulsed phenomena in dielectric-barrier atmospheric-pressure glow discharges

    SciTech Connect

    Ha Yan [College of Mathematics and Computer Science, Hebei University, Baoding 071002 (China); Wang Huijuan [School of Mathematics and Physics, North China Electric Power University, Baoding 071003 (China); Wang Xiaofei [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)

    2012-01-15

    Asymmetric current pulses in dielectric-barrier atmospheric-pressure glow discharges are investigated by a self-consistent, one-dimensional fluid model. It is found that the glow mode and Townsend mode can coexist in the asymmetric discharge even though the gas gap is rather large. The reason for this phenomenon is that the residual space charge plays the role of anode and reduces the gap width, resulting in the formation of a Townsend discharge.

  20. The effect of atmospheric phenomena on sea-level variability in the North-East Atlantic from satellite altimetry data

    NASA Astrophysics Data System (ADS)

    Barbosa, Susana

    Sea-level is a fundamental geophysical parameter. The height of the sea surface is influenced by density and mass changes in the ocean as well as in the atmosphere above it, providing infor-mation on both oceanographic and atmospheric phenomena. This work addresses the influence of atmospheric effects on sea-level variability in the North-East Atlantic, by examining the correlation between satellite altimetry observations and the North Atlantic Oscillation (NAO) index. The NAO, characterised by a net displacement of atmospheric mass between the Arctic and the middle latitudes, is a major atmospheric phenomenon in the North Atlantic region, influencing climate variability over Europe. The effect of the state of the NAO on sea-level variability is assessed by the correlation between the monthly NAO index, obtained by rotated principal component analysis, and monthly-aggregated satellite altimetry observations. The satellite data were taken from the Topex/Poseidon and Jason-1 missions, from 1993 to 2008, and three different options were considered to account for the effect of atmospheric pressure on the height of the sea surface: i) a static, inverse barometer correction with a static ref-erence pressure ii) a dynamic inverse barometer correction based on MOG2D model and iii) no inverse barometer correction. The results show that sea-level in the North-East Atlantic is anti-correlated with the state of the NAO index. A positive NAO state is associated with higher atmospheric pressure values over the study area and therefore lower sea-levels. The correlation is strongest when considering the satellite observations which were not corrected for pressure effects. The correlation between the height of the sea surface and the state of the NAO index decreases slightly when considering the data corrected for pressure effects via the static inverse barometer response and becomes negligible when the correction for pressure effects is based on the MOG2D model. These results emphasize the relevance of high-frequency effects on the NAO contribution to sea-level variability. The state of the NAO influences sea-levels over the study area mainly via wind rather than a direct pressure effect.

  1. What can Cloud-Resolving Models Tell us About Critical Phenomena in Atmospheric Precipitation?

    NASA Astrophysics Data System (ADS)

    Krueger, S. K.; Kochanski, A.

    2009-12-01

    Recent work suggests that observations of Tropical precipitation conform to properties associated with critical phenomena of other systems (Peters and Neelin 2006). The precipitation retrievals are averages over 25-km by 25-km areas and are snapshots in time, and therefore unable to reveal the underlying, smaller-scale physical processes. We are using a 3D cloud-resolving model (CRM) to resolve these processes in space and time, and thereby allow us to investigate the underlying physics in detail. The CRM was run over a large domain (1000 km by 1000 km) for a long time (~10 days) in order to adequately sample the rare large events. In addition, we are using results from a 4-year global simulation using a climate model based on the multi-scale modeling framework (MMF). Whereas conventional parameterizations are based on statistical theories involving uncertain closure assumptions, MMFs represent cloud processes on their native scales by embedding a 2D CRM with a 4-km horizontal grid size in each climate model grid column. We have analyzed the model results following the methodology of Peters and Neelin. We used the results to produce rainfall rates conditioned on column water vapor and column temperature over the Tropical oceans. We have also analyzed additional statistical aspects of Tropical convection in the 3D CRM simulations that are related to critical behavior. We have found that: (1) CRMs are able to reproduce nearly all of the observed statistics of strong convective precipitation over tropical oceans. (2) CRMs and MMFs do not generally reproduce the observed roll-off of precipitation rate at large column water vapor values. (3) Analysis of CRM results suggests that many of the observed features are due to the tight coupling between dynamics and moist thermodynamics in convective updrafts.

  2. What can Cloud-Resolving Models Tell us About Critical Phenomena in Atmospheric Precipitation?

    NASA Astrophysics Data System (ADS)

    Krueger, S. K.; Kochanski, A. K.

    2009-05-01

    Recent work suggests that observations of tropical precipitation conform to properties associated with critical phenomena of other systems (Peters and Neelin 2006). The measurements are averages over 25-km by 25- km areas and are snapshots in time, and therefore unable to reveal the underlying, smaller-scale physical processes. We are using a 3D cloud-resolving model (CRM) to resolve these processes in space and time, and thereby allow us to investigate the underlying physics in detail. The model is being run over a large domain (1000 km by 1000 km) for a long time (many days) in order to adequately sample the rare events. In addition, we are using results from a global climate model that is based on the multi-scale modeling framework (MMF). Whereas conventional parameterizations are based on statistical theories involving uncertain closure assumptions, MMFs represent cloud processes on their native scales, by embedding a 2D CRM with a 4-km horizontal grid size in each climate model grid column. We are analyzing the model results following the methodology of Peters and Neelin. We are using MMF results to produce rainfall rates conditioned on column water vapor and column temperature over the Tropical oceans. We are doing the same with 3D CRM results. Furthermore, we are comparing 2D and 3D CRM results and examining the impact of CRM horizontal grid size. We are also analyzing additional statistical aspects of Tropical convection in the 3D CRM simulations that are related to critical behavior, such as size distributions and other geometric properties of mesoscale convective systems, identified as clusters of adjacent pixels exceeding a precipitation threshold. And to evaluate the realism of the statistical properties of deep convection simulated by the 3D CRM, we are comparing its vertical velocity statistics and rainfall rate PDFs to observations from aircraft and precipitation radars, respectively.

  3. Opto-acoustic phenomena accompanying the propagation of high-power pulsed laser radiation in the atmosphere

    NASA Astrophysics Data System (ADS)

    Chistyakova, Liliya K.; Shamanaeva, Lyudmila G.

    2003-03-01

    Opto-acoustic phenomena accompanying the propagation of high-power pulsed laser radiation in the atmosphere are used for remote determination of the energetic and geometric parameters of laser radiation. The amplitudes and shapes of acoustic pulses have been calculated for the following typical temporal behavior of Gaussian beams: a triggering pulse, short laser pulse, and harmonically modulated radiation disregarding the effect of kinetic cooling in the laser beam propagation channel. Numerical calculations allow one to determine experimentally the radiation power and the absorption coefficient in air for the chosen mode of laser radiation, because the difference between the calculated dimensionless and measured normalized sound pressure levels remains constant for each temporal behavior and is a function of the sought-after parameters. It is experimentally demonstrated that the geometric and energetic characteristics of laser beams measured by opto-acoustic methods agree well with the results of contact bolometer measurements. The standard deviation does not exceed 15% for the laser energy density W <= 13 J/cm2. For W > 13 J/cm2, the observed discrepancy of the results is explained by nonlinearity of bolometer sensors. An algorithm of reconstructing the spatial structure of laser beams from the data of wire bolometer sensors is suggested and realized. The optimal number of initial projections and readings for each projection has allowed us to reconstruct the beam spatial structure in real time. The algorithm is efficient when the noise level does not exceed 20%. The nonlinear extinction coefficient of laser radiation in the atmosphere also can be retrieved from opto-acoustic measurements without additional information about optical and meteorological situation.

  4. Transformation and birth processes of the transient luminous phenomena's in the low atmosphere of the Hessdalen valley, Norway.

    NASA Astrophysics Data System (ADS)

    Gitle Hauge, Bjørn; Strand, Erling

    2013-04-01

    Transient louminous phenomenas has been observed in and over the Hessdalen valley for over 100 years. These phenomena's has been nicknamed "Hessdalen phenomenas", HP, and has been under permanent scientific investigation since 1998, when Norwegian, Italian and later French researchers installed different types of monitoring equipment in the valley. The earth's magnetic field, electromagnetic radiation in different bands, radioactive radiation, electrical resistance in the ground, ultrasound, and seismic activity are some of the signals/parameters that has been monitored. The valley has also been surveillanced by radar, optical spectrometers and automatic video recording devices. So far no electromagnetic radiation, except in the optical band, has been detected that can be coupled to the HP. The phenomenon is characterized by its horizontal movement, intense optical radiation when a transformation process occurs, different colours where white/yellow dominates, no sound, high speed, unpredictable flight patterns, seen by radar while optical invisible and often observed with continuous optical spectrum. The phenomena have been seen touching ground, without leaving burning marks and flying in higher altitudes over the valley apparently ignoring wind/weather conditions. The Hessdalen valley is located in the middle of Norway and is famous for its mines with iron, zinc and copper ore. Big deposits of ore still reside inside the valley, and the mountains are penetrated by several mineshafts, some has depth down to 1000m. No exact birthplace has been located and the phenomenon seems to emerge "out of thin air" anywhere in the valley. Any activity coupled to mineshafts has not been observed. In September 2006 a birth and transformation process was observed and several optical spectrums was obtained. The phenomena appear as a big white light possibly not more than some hundred meters above the ground in a desolated area. The phenomenon starts a transformation process dividing itself into two light balls where the light-intensity increases and showing a continuous optical spectrum. Later on the light intensity decreases and the continuous optical spectrum is broken up and emission lines appearing, as if the phenomenon goes from a plasma to a gas state. The process ends up when two round light balls are formed, with low optical intensity and red colour, showing sign of a thermal process loosing energy. This observation is to be documented and analyzed.

  5. Future monitoring of charged particle energy deposition into the upper atmosphere and comments on possible relationships between atmospheric phenomena and solar and/or geomagnetic activity

    NASA Technical Reports Server (NTRS)

    Williams, D. J.; Grubb, R. N.; Evans, D. S.; Sauer, H. H.

    1974-01-01

    The charged particle observations proposed for the new low altitude weather satellites, TIROS-N, are described that will provide the capability of routine monitoring of the instantaneous total energy deposition into the upper atmosphere by the precipitation of charged particles from higher altitudes. Estimates are given to assess the potential importance of this type of energy deposition. Discussion and examples are presented illustrating the importance in distinguishing between solar and geomagnetic activity as possible causative sources.

  6. Vacuum Arc Anode Phenomena

    Microsoft Academic Search

    H. Craig Miller

    1977-01-01

    This paper presents a brief review of anode phenomena in vacuum arcs. It discusses in succession the transition of the arc into the anode spot mode; the temperature of the anode before, during, and after formation of an anode spot; and anode ions. Characteristically the anode spot has a temperature of the order of the atmospheric boiling point of the

  7. Atmosphere

    NSDL National Science Digital Library

    University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

    2003-01-01

    What is this atmosphere that surrounds the Earth? This instructional tutorial, part of an interactive laboratory series for grades 8-12, introduces students to the structure, effects, and components of the atmosphere. Here students investigate the composition of the atmosphere; effects of temperature, pressure, and ozone; the greenhouse effect; and how Earth compares with other planets. Interactive activities present students with opportunities to explore ideas and answer questions about the atmosphere, including its structure, the making of ozone, rocket launching, and measuring the atmosphere. Pop-up boxes provide additional information on topics such as dust, rain, and atmospheric composition. Students complete a final written review of six questions about the atmosphere. Copyright 2005 Eisenhower National Clearinghouse

  8. A Compact Monitoring System for Recording X-Rays, Gamma Rays and Neutrons Generated By Atmospheric Lightning Discharges and Other Natural Phenomena

    NASA Astrophysics Data System (ADS)

    Martin, I. M.; Alves, M. A.

    2009-12-01

    The generation of X-rays, gamma-rays and neutrons by atmospheric lightning discharges has been predicted by different researchers several decades ago. But only within the last 25 years the first experimental evidences of events relating the generation of these radiations with lightning have been made; since then there is a continuing effort to collect more information about this type of phenomenon. In this study we describe a compact monitoring system to detect simultaneously X-rays, gamma-rays and neutrons using rather inexpensive off-the-shelf commercial detectors (Micro Roengten Radiation Monitor, 8-inch gamma tube coupled to a 3x3 inch sodium iodide [Nai(Tl)] crystal, Ludlum He-3 neutron detector) and accompanying computer interfaces. The system is extremely portable and can be powered with small automotive batteries, if necessary. Measurements are performed at ground-level. Preliminary measurements have already yielded positive results, e.g., changes in the neutron flux related to a lightning discharge and varying weather conditions have been observed in the city of Sao Jose dos Campos, Brazil (23° 11? 11?S, 45° 52? 43? W, 600 m above sea level). This a pilot study, in the near future a larger number of these compact monitoring system will be installed in different location in order to increase the area coverage. Although the main objective of the study is to detect high-energy events produced by lightning discharges, the monitoring system will also be able to detect changes in the radiation background produced by other natural phenomena.

  9. Atmospheric Dispersion Lecture Atmospheric Local-Scale Dispersion Modelling.

    E-print Network

    pressure centers (its the opposite on the #12;Southern Hemisphere.) Atmospheric boundary layerAtmospheric Dispersion Lecture Atmospheric Local-Scale Dispersion Modelling. Lecturer: Dr Torben) Learning aims ! To understand the basic phenomena of atmospheric dispersion and deposition. ! To understand

  10. Atmospheres

    NASA Astrophysics Data System (ADS)

    Bott, June; Yin, Hongbin; Sridhar, Seetharaman

    2014-12-01

    When high Al containing Fe alloys such as TRIP steels are exposed to atmospheres that contain N2 during re-heating, sub-surface nitrides form and these can be detrimental to mechanical properties. Nitride precipitation can be controlled by minimizing the access of the gaseous atmosphere to the metal surface, which can be achieved by a rapid growth of a continuous and adherent surface scale. This investigation utilizes a Au-image furnace attached to a confocal scanning microscope to simulate the annealing temperature vs time while Fe-Al alloys (with Al contents varying from 1 to 8 wt pct) are exposed to a O2-N2 atm with 10-6 atm O2. The heating times of 1, 10, and 100 minutes to the isothermal temperature of 1558 K (1285 °C) were used. It was found that fewer sub-surface nitride precipitates formed when the heating time was lowered and when Al content in the samples was increased. In the 8 wt pct samples, no internal nitride precipitates were present regardless of heating time. In the 3 and 5 wt pct samples, internal nitride precipitates were nearly more or less absent at heating times less than 10 minutes. The decrease in internal precipitates was governed by the evolving structure of the external oxide-scale. At low heating rates and/or low Al contents, significant Fe-oxide patches formed and these appeared to allow for ingress of gaseous N2. For the slow heating rates, ingress could have happened during the longer time spent in lower temperatures where non-protective alumina was present. As Al content in the alloy was increased, the external scale was Al2O3 and/or FeAl2O4 and more continuous and consequently hindered the N2 from accessing the metal surface. Increasing the Al content in the alloy had the effect of promoting the outward diffusion of Al in the alloy and thereby assisting the formation of the continuous external layer of Al2O3 and/or FeAl2O4.

  11. Crystallization phenomena in slags

    NASA Astrophysics Data System (ADS)

    Orrling, Carl Folke

    2000-09-01

    The crystallization of the mold slag affects both the heat transfer and the lubrication between the mold and the strand in continuous casting of steel. In order for mold slag design to become an engineering science rather than an empirical exercise, a fundamental understanding of the melting and solidification behavior of a slag must be developed. Thus it is necessary to be able to quantify the phenomena that occur under the thermal conditions that are found in the mold of a continuous caster. The double hot thermocouple technique (DHTT) and the Confocal Laser Scanning Microscope used in this study are two novel techniques for investigating melting and solidification phenomena of transparent slags. Results from these techniques are useful in defining the phenomena that occur when the slag film infiltrates between the mold and the shell of the casting. TTT diagrams were obtained for various slags and indicated that the onset of crystallization is a function of cooling rate and slag chemistry. Crystal morphology was found to be dependent upon the experimental temperature and four different morphologies were classified based upon the degree of melt undercooling. Continuous cooling experiments were carried out to develop CCT diagrams and it was found that the amount and appearance of the crystalline fraction greatly depends on the cooling conditions. The DHTT can also be used to mimic the cooling profile encountered by the slag in the mold of a continuous caster. In this differential cooling mode (DCT), it was found that the details of the cooling rate determine the actual response of the slag to a thermal gradient and small changes can lead to significantly different results. Crystal growth rates were measured and found to be in the range between 0.11 mum/s to 11.73 mum/s depending on temperature and slag chemistry. Alumina particles were found to be effective innoculants in oxide melts reducing the incubation time for the onset of crystallization and also extending the temperature range of observed crystallization. The effect of changing the gas atmosphere surrounding the sample has been studied. The presence of water vapor increased the nucleation rate and crystal growth rate significantly when compared to experiments carried out in a dry atmosphere. With an atmosphere of Argon and Argon-3% Hydrogen mixture, the incubation time for crystallization was increased with several minutes. The crystal growth rate in these atmospheres was also drastically reduced compared to an atmosphere of normal air. Significant numbers of bubbles were formed during the initial melting of mold slag samples and the melting rate of the slag was found to be related to the rate of bubble generation and to the rate of heat transport.

  12. Global and frequent appearance of small spatial scale field-aligned currents possibly driven by the lower atmospheric phenomena as observed by the CHAMP satellite in middle and low latitudes

    NASA Astrophysics Data System (ADS)

    Nakanishi, Kunihito; Iyemori, Toshihiko; Taira, Kento; Lühr, Hermann

    2014-12-01

    Using magnetic field data obtained by the Challenging Minisatellite Payload (CHAMP), we show global and frequent appearance of small-amplitude (1 to 5 nT on the dayside) magnetic fluctuations with period around a few tens of seconds along the satellite orbit in middle and low latitudes. They are different from known phenomena, such as the Pc3 pulsations. The following characteristics are presented and discussed in this paper: (1) The magnetic fluctuations are perpendicular to the geomagnetic main field, and the amplitude of the zonal (east-west) component is larger than that of the meridional component in general. (2) As latitude becomes lower around the dip equator, the period tends to become longer. (3) The amplitudes have clear local time dependence, which is highly correlated to the ionospheric conductivities in local time (LT) 06-18. (4) The amplitude of the fluctuations shows magnetic conjugacy to a certain extent. (5) The amplitude shows no dependence on solar wind parameters nor geomagnetic activity. (6) A seasonal dependence is seen clearly. The amplitudes in the northern summer and winter are larger than those in the equinoxes. In the northern summer, the amplitudes above the Eurasian and South American continents and their conjugate areas are larger. In the northern winter, those above the eastern Pacific Ocean are larger. We suggest that the above characteristics, (1) to (6), can be attributed to the small spatial scale field-aligned currents having a lower atmospheric origin through the ionospheric dynamo process.

  13. Planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Leovy, C.

    1987-03-01

    Observations and theoretical models of planetary atmospheres published during the period 1983-1986 are reviewed, including Vega and Voyager data and results from ground-based remote sensing. Consideration is given to water-vapor and sulfur-compound distributions, electrical phenomena, and dynamics in the Venus atmosphere; dust storms, water cycles, and water and ice erosion on Mars; the compositions, temperature profiles, and dynamics of the Jovian and Saturnian atmospheres; chemical processes and zonal winds on Titan; and the radiation budgets and chemical compositions of the outer planets.

  14. Single event phenomena in atmospheric neutron environments

    Microsoft Academic Search

    C. A. Gossett; B. W. Hughlock; M. Katoozi; G. S. LaRue; S. A. Wender

    1993-01-01

    Describes direct experimental measurements of neutron-induced single event effect (SEE) rates in commercial high-density static random access memories in a neutron environment characteristic of that at commercial airplane altitudes. The first experimental measurements testing current models for neutron-silicon burst generation rates are presented, as well as measurements of charge collection in silicon test structures as a function of neutron energy.

  15. Vacuum Arc Anode Phenomena

    Microsoft Academic Search

    H. Craig Miller

    1983-01-01

    This paper briefly reviews anode phenomena in vacuum arcs, specially experimental work. It discusses, in succession, arc modes at the anode, anode temperature measurements, anode ions, transitions of the arc into various modes (principally the anode spot mode), and theoretical explanations of anode phenomena. The two most common anode modes in a vacuum arc are a low current mode where

  16. Science and Paranormal Phenomena

    SciTech Connect

    Noyes, H. Pierre

    1999-06-03

    In order to ground my approach to the study of paranormal phenomena, I first explain my operational approach to physics, and to the ''historical'' sciences of cosmic, biological, human, social and political evolution. I then indicate why I believe that ''paranormal phenomena'' might-but need not- fit into this framework. I endorse the need for a new theoretical framework for the investigation of this field presented by Etter and Shoup at this meeting. I close with a short discussion of Ted Bastin's contention that paranormal phenomena should be defined as contradicting physics.

  17. Science and Paranormal Phenomena

    E-print Network

    Noyes, H P

    1999-01-01

    In order to ground my approach to the study of paranormal phenomena, I first explain my operational approach to physics, and to the ``historical'' sciences of cosmic, biological, human, social and political evolution. I then indicate why I believe that ``paranormal phenomena'' might --- but need not --- fit into this framework. I endorse the need for a new theoretical framework for the investigation of this field presented by Etter and Shoup at this meeting. I close with a short discussion of Ted Bastin's contention that paranormal phenomena should be {\\it defined} as contradicting physics.

  18. Science and Paranormal Phenomena

    E-print Network

    H. Pierre Noyes

    1999-06-03

    In order to ground my approach to the study of paranormal phenomena, I first explain my operational approach to physics, and to the ``historical'' sciences of cosmic, biological, human, social and political evolution. I then indicate why I believe that ``paranormal phenomena'' might --- but need not --- fit into this framework. I endorse the need for a new theoretical framework for the investigation of this field presented by Etter and Shoup at this meeting. I close with a short discussion of Ted Bastin's contention that paranormal phenomena should be {\\it defined} as contradicting physics.

  19. Layered phenomena in the mesopause region

    NASA Astrophysics Data System (ADS)

    Plane, J. M. C.; Bailey, S. M.; Baumgarten, G.; Rapp, M.

    2015-05-01

    This special issue of the Journal of Atmospheric and Solar-Terrestrial Physics comprises a collection of papers which were mostly presented at the 11th Layered Phenomena in the Mesopause Region (LPMR) Workshop, held at the University of Leeds between 29th July 2013 and 1st August 2013. The topics covered at the workshop included atmospheric dynamics, mesospheric ice clouds, meteoric metal layers, meteoric smoke particles, and airglow layers. There was also a session on the potential of planned sub-orbital spacecraft for making measurements in the mesosphere and lower thermosphere (MLT).

  20. Stress pulse phenomena

    SciTech Connect

    McGlaun, M.

    1993-08-01

    This paper is an introductory discussion of stress pulse phenomena in simple solids and fluids. Stress pulse phenomena is a very rich and complex field that has been studied by many scientists and engineers. This paper describes the behavior of stress pulses in idealized materials. Inviscid fluids and simple solids are realistic enough to illustrate the basic behavior of stress pulses. Sections 2 through 8 deal with the behavior of pressure pulses. Pressure is best thought of as the average stress at a point. Section 9 deals with shear stresses which are most important in studying solids.

  1. Transport phenomena in nanofluidics

    Microsoft Academic Search

    Reto B. Schoch; Jongyoon Han; Philippe Renaud

    2008-01-01

    The transport of fluid in and around nanometer-sized objects with at least one characteristic dimension below 100nm enables the occurrence of phenomena that are impossible at bigger length scales. This research field was only recently termed nanofluidics, but it has deep roots in science and technology. Nanofluidics has experienced considerable growth in recent years, as is confirmed by significant scientific

  2. Atmosphere-Ionosphere Electrodynamic Coupling

    Microsoft Academic Search

    V. M. Sorokin; V. M. Chmyrev

    2010-01-01

    Numerous phenomena that occur in the mesosphere, ionosphere, and the magnetosphere of the Earth are caused by the sources located in the lower atmosphere and on the ground. We describe the effects produced by lightning activity and by ground-based transmitters operated in high frequency (HF) and very low frequency (VLF) ranges. Among these phenomena are the ionosphere heating and the

  3. Membrane Transport Phenomena (MTP)

    NASA Technical Reports Server (NTRS)

    Mason, Larry W.

    1997-01-01

    The third semi-annual period of the MTP project has been involved with performing experiments using the Membrane Transport Apparatus (MTA), development of analysis techniques for the experiment results, analytical modeling of the osmotic transport phenomena, and completion of a DC-9 microgravity flight to test candidate fluid cell geometries. Preparations were also made for the MTP Science Concept Review (SCR), held on 13 June 1997 at Lockheed Martin Astronautics in Denver. These activities are detailed in the report.

  4. Mutual interaction of soil moisture state and atmospheric processes

    Microsoft Academic Search

    Dara Entekhabi; Ignacio Rodriguez-Iturbe; Fabio Castelli

    1996-01-01

    The purpose of this paper is to outline the pathways through which soil moisture and meteorological phenomena mutually influence one another at local, regional and global scales. This constitutes two-way land-atmosphere interaction, as meteorological phenomena both act as the forcing and react to the forcing by the soil moisture state. Land surface modification of the atmospheric environment and the atmospheric

  5. Atmospheric re-entry

    NASA Astrophysics Data System (ADS)

    East, Robin A.

    Atmospheric reentry and aero-assisted orbited transfer are discussed. The aerodynamic features of the range of atmospheric braking and maneuvering space vehicles are determined by the velocity-altitude regime of the atmospheric flight. A comparison of the flight regimes of several of the vehicles proposed for earth atmosphere encounters is presented. A typical entry altitude where the 'top' of the earth's atmosphere is encountered (about 150 km). The bulk of the trajectories for the Space Shuttle orbiter, Apollo reentry, ICBM, and AMOOS lie within the continuum flow regime. For AOTVs and plane change vehicles, a significant fraction of the atmospheric encounter occurs in a very energetic rarefied flow regime. Chemical nonequilibrium effects, radiative heat transfer, and air ionization are phenomena which have a major influence on AOTVs. Ballistic entry at large angles of descent, lifting entry, thermal protection systems, and the entry corridor are discussed.

  6. MULTISCALE PHENOMENA IN MATERIALS

    SciTech Connect

    A. BISHOP

    2000-09-01

    This project developed and supported a technology base in nonequilibrium phenomena underpinning fundamental issues in condensed matter and materials science, and applied this technology to selected problems. In this way the increasingly sophisticated synthesis and characterization available for classes of complex electronic and structural materials provided a testbed for nonlinear science, while nonlinear and nonequilibrium techniques helped advance our understanding of the scientific principles underlying the control of material microstructure, their evolution, fundamental to macroscopic functionalities. The project focused on overlapping areas of emerging thrusts and programs in the Los Alamos materials community for which nonlinear and nonequilibrium approaches will have decisive roles and where productive teamwork among elements of modeling, simulations, synthesis, characterization and applications could be anticipated--particularly multiscale and nonequilibrium phenomena, and complex matter in and between fields of soft, hard and biomimetic materials. Principal topics were: (i) Complex organic and inorganic electronic materials, including hard, soft and biomimetic materials, self-assembly processes and photophysics; (ii) Microstructure and evolution in multiscale and hierarchical materials, including dynamic fracture and friction, dislocation and large-scale deformation, metastability, and inhomogeneity; and (iii) Equilibrium and nonequilibrium phases and phase transformations, emphasizing competing interactions, frustration, landscapes, glassy and stochastic dynamics, and energy focusing.

  7. Attoheat transport phenomena

    E-print Network

    J. Marciak-Kozlowska; M. Pelc; M. A. Kozlowski

    2009-06-09

    Fascinating developments in optical pulse engineering over the last 20 years lead to the generation of laser pulses as short as few femtosecond, providing a unique tool for high resolution time domain spectroscopy. However, a number of the processes in nature evolve with characteristic times of the order of 1 fs or even shorter. Time domain studies of such processes require at first place sub-fs resolution, offered by pulse depicting attosecond localization. The generation, characterization and proof of principle applications of such pulses is the target of the attoscience. In the paper the thermal processes on the attosecond scale are described. The Klein-Gordon and Proca equations are developed. The relativistic effects in the heat transport on nanoscale are discussed. It is shown that the standard Fourier equation can not be valid for the transport phenomena induced by attosecond laser pulses. The heat transport in nanoparticles and nanotubules is investigated.

  8. Weld pool phenomena

    SciTech Connect

    David, S.A.; Vitek, J.M.; Zacharia, T. [Oak Ridge National Lab., TN (United States); DebRoy, T. [Pennsylvania State Univ., University Park, PA (United States)

    1994-09-01

    During welding, the composition, structure and properties of the welded structure are affected by the interaction of the heat source with the metal. The interaction affects the fluid flow, heat transfer and mass transfer in the weld pool, and the solidification behavior of the weld metal. In recent years, there has been a growing recognition of the importance of the weld pool transport processes and the solid state transformation reactions in determining the composition, structure and properties of the welded structure. The relation between the weld pool transport processes and the composition and structure is reviewed. Recent applications of various solidification theories to welding are examined to understand the special problems of weld metal solidification. The discussion is focussed on the important problems and issues related to weld pool transport phenomena and solidification. Resolution of these problems would be an important step towards a science based control of composition, structure and properties of the weld metal.

  9. Superlattice Phenomena in Nanohelices

    NASA Astrophysics Data System (ADS)

    Downing, Charles; Robinson, Matthew; Portnoi, Mikhail; University of Exeter Team

    2015-03-01

    Recently artificially-created nanohelices have been demonstrated in various semiconductor systems. We argue that subjecting a nanohelix to an electric field normal to its axis turns it into a superlattice with easily-tunable electronic properties. We investigate such a system, also subjected to a longitudinal electric field along the nanotube axis, and find Bloch oscillations and negative differential conductivity. Taking into account Zener tunneling across the band gap, we find the characteristic N-type dependence of electron drift velocity on the longitudinal field which is commonly used in high-frequency electronics. The merits of using a nanohelix for novel tunable device applications are assessed. We also study dipole transitions across the energy gap, which can be tuned to the THz range by experimentally attainable external fields. There is a drastic change in selection rules for a helix in a transverse field compared to the case of purely chiral structures. For the excitation propagating along the nanohelix axis our results are somewhat similar to those found for a quantum ring pierced by a magnetic flux, with the momentum of a quasiparticle in a helix playing the same role as a flux through a ring. We also discuss possible devices which could utilize these phenomena.

  10. ON DETECTING TRANSIENT PHENOMENA

    SciTech Connect

    Belanger, G., E-mail: gbelanger@sciops.esa.int [European Space Astronomy Centre (ESA/ESAC), Science Operations Department, Villanueva de la Canada (Madrid) (Spain)

    2013-08-10

    Transient phenomena are interesting and potentially highly revealing of details about the processes under observation and study that could otherwise go unnoticed. It is therefore important to maximize the sensitivity of the method used to identify such events. In this article, we present a general procedure based on the use of the likelihood function for identifying transients which is particularly suited for real-time applications because it requires no grouping or pre-processing of the data. The method makes use of all the information that is available in the data throughout the statistical decision-making process, and is suitable for a wide range of applications. Here we consider those most common in astrophysics, which involve searching for transient sources, events or features in images, time series, energy spectra, and power spectra, and demonstrate the use of the method in the case of a weak X-ray flare in a time series and a short-lived quasi-periodic oscillation in a power spectrum. We derive a fit statistic that is ideal for fitting arbitrarily shaped models to a power density distribution, which is of general interest in all applications involving periodogram analysis.

  11. Arcjet cathode phenomena

    NASA Technical Reports Server (NTRS)

    Curran, Francis M.; Haag, Thomas W.; Raquet, John F.

    1989-01-01

    Cathode tips made from a number of different materials were tested in a modular arcjet thruster in order to examine cathode phenomena. Periodic disassembly and examination, along with the data collected during testing, indicated that all of the tungsten-based materials behaved similarly despite the fact that in one of these samples the percentage of thorium oxide was doubled and another was 25 percent rhenium. The mass loss rate from a 2 percent thoriated rhenium cathode was found to be an order of magnitude greater than that observed using 2 percent thoriated tungsten. Detailed analysis of one of these cathode tips showed that the molten crater contained pure tungsten to a depth of about 150 microns. Problems with thermal stress cracking were encountered in the testing of a hafnium carbide tip. Post test analysis showed that the active area of the tip had chemically reacted with the propellant. A 100 hour continuous test was run at about 1 kW. Post test analysis revealed no dendrite formation, such as observed in a 30 kW arcjet lifetest, near the cathode crater. The cathodes from both this test and a previously run 1000 hour cycled test displayed nearly identical arc craters. Data and calculations indicate that the mass losses observed in testing can be explained by evaporation.

  12. Arcjet Cathode Phenomena

    NASA Technical Reports Server (NTRS)

    Curran, Francis M.; Haag, Thomas W.; Raquet, John F.

    1989-01-01

    Cathode tips made from a number of different materials were tested in a modular arcjet thruster in order to examine cathode phenomena. Periodic disassembly and examination, along with the data collected during testing, indicated that all of the tungsten-based materials behaved similarly despite the fact that in one of these samples the percentage of thorium oxide was doubled and another was 25 percent rhenium. The mass loss rate from a 2 percent thoriated rhenium cathode was found to be an order of magnitude greater than that observed using 2 percent thoriated tungsten. Detailed analysis of one of these cathode tips showed that the molten crater contained pure tungsten to a depth of about 150 microns. Problems with thermal stress cracking were encountered in the testing of a hafnium carbide tip. Post test analysis showed that the active area of the tip had chemically reacted with the propellant. A 100 hour continuous test was run at about 1 kW. Post test analysis revealed no dendrite formation, such as observed in a 30 kW arcjet lifetest, near the cathode crater. The cathodes from both this test and a previously run 1000 hour cycled test displayed nearly identical arc craters. Data and calculations indicate that the mass losses observed in testing can be explained by evaporation.

  13. Physical phenomena disturbing LIBS analysis

    Microsoft Academic Search

    A. Sarzynski; W. Skrzeczanowski; J. Marczak

    2007-01-01

    An influence of some physical phenomena disturbing correct interpretation of LIBS spectra is described in the paper. The following phenomena were investigated: a way of laser beam focusing (power density), laser spark in air, spectral line broadening, apparatus efficiency and resolution, and an influence of those factors on LIBS spectra as well. They are particularly important for quantitative LIBS measurements.

  14. Atmospheric transport and diffusion mechanisms in coastal circulation systems

    SciTech Connect

    Kaleel, R.J.; Shearer, D.L.; MacRae, B.L.

    1983-06-01

    This study defines the cyclical aspects of coastal atmospheric behavior that are important to the transport and diffusion (dispersion) of radionuclides. The report is developed around discussions of the meteorological dynamics of the cyclical and (cellular) atmospheric coastal phenomena and the atmospheric transport/diffusion mechanisms along with an assessment of the measurements accompanying both. Further, the efforts directed to modeling both the atmospheric and transport/diffusion processes are summarized and evaluated. Lastly, the review is summarized through a set of conclusions about the current level of understanding of coastal atmospheric phenomena. Recommendations are offered which identify certain aspects of local scale cyclical coastal phenomena that are important to the NRC.

  15. Atmosphere–Ionosphere Electrodynamic Coupling

    Microsoft Academic Search

    V. M. Sorokin; V. M. Chmyrev

    \\u000a Numerous phenomena that occur in the mesosphere, ionosphere, and the magnetosphere of the Earth are caused by the sources\\u000a located in the lower atmosphere and on the ground. We describe the effects produced by lightning activity and by ground-based\\u000a transmitters operated in high frequency (HF) and very low frequency (VLF) ranges. Among these phenomena are the ionosphere\\u000a heating and the

  16. Visible Earth: Atmosphere

    NSDL National Science Digital Library

    This site is part of Visible Earth, which is hosted by the National Aeronautics and Space Administration (NASA), and contains a searchable directory of images, visualizations, and animations of the Earth. This section contains images of the Earth's atmosphere, which includes aerosols, air quality, atmospheric phenomena, pressure, radiation, temperature, water, winds, clouds, precipitation, and earth's radiation bidget. Each image is available in a variety of resolutions and sizes, with a brief description, credit, date, and the name of the spacecraft or instrument that captured the image.

  17. Global atmospheric changes.

    PubMed Central

    Piver, W T

    1991-01-01

    Increasing concentrations of CO2 and other greenhouse gases in the atmosphere can be directly related to global warming. In terms of human health, because a major cause of increasing atmospheric concentrations of CO2 is the increased combustion of fossil fuels, global warming also may result in increases in air pollutants, acid deposition, and exposure to ultraviolet (UV) radiation. To understand better the impacts of global warming phenomena on human health, this review emphasizes the processes that are responsible for the greenhouse effect, air pollution, acid deposition, and increased exposure to UV radiation. PMID:1820255

  18. Physical phenomena disturbing LIBS analysis

    NASA Astrophysics Data System (ADS)

    Sarzy?ski, A.; Skrzeczanowski, W.; Marczak, J.

    2007-07-01

    An influence of some physical phenomena disturbing correct interpretation of LIBS spectra is described in the paper. The following phenomena were investigated: a way of laser beam focusing (power density), laser spark in air, spectral line broadening, apparatus efficiency and resolution, and an influence of those factors on LIBS spectra as well. They are particularly important for quantitative LIBS measurements. The presented measurement results clearly show that the correct elemental identification plays a significant role in artworks dating [5].

  19. Interaction with Atmosphere

    Microsoft Academic Search

    Detlef Breitling; Sergei Klimentov; Friedrich Dausinger

    Contrary to longer-pulsed laser irradiation, ultrashort laser pulses in the femto- and low picosecond-pulse duration domains are expected to be too short to interact directly with the material vapor they produce during ablation. Nonetheless, the very high intensities reached by focused ultrashort pulses cause a number of interaction phenomena of the pulses with the ambient atmosphere. The various effects are discussed

  20. Rendering Ghost Ships and Other Phenomena in Arctic Atmospheres

    E-print Network

    Gutierrez, Diego

    ghost ship legends), the Fata Morgana or the Novaya-Zemlya effect. We present here an implementation Morgana or the Novaya-Zemlya remain mostly unknown. We present here our ray tracing method to reproduce

  1. Critical velocity phenomena and the LTP. [Lunar Transient Phenomena

    NASA Technical Reports Server (NTRS)

    Srnka, L. J.

    1977-01-01

    When the relative velocity between magnetized plasma and neutral gas exceeds a critical value, the gas-plasma interaction is dominated by collective phenomena which rapidly excite and ionize the neutrals. The interaction of the solar wind with a large cloud (between 10 to the 24th and 10 to the 28th power neutrals) vented from the moon should be of this type. Line radiation from such an interaction can yield an apparent lunar surface brightness rivaling reflected sunlight levels over small areas, if the kinetic-energy flow density of the gas is sufficiently high. The aberrated solar-wind flow past the moon would enhance the visibility of such interactions near the lunar sunrise terminator, supporting the statistical studies which indicate that the 'Lunar Transient Phenomena' (anomalous optical phenomena on the moon) are significantly correlated with the position of the terminator on the lunar surface.

  2. Transport Phenomena and Materials Processing

    NASA Astrophysics Data System (ADS)

    Kou, Sindo

    1996-10-01

    An extremely useful guide to the theory and applications of transport phenomena in materials processing This book defines the unique role that transport phenomena play in materials processing and offers a graphic, comprehensive treatment unlike any other book on the subject. The two parts of the text are, in fact, two useful books. Part I is a very readable introduction to fluid flow, heat transfer, and mass transfer for materials engineers and anyone not yet thoroughly familiar with the subject. It includes governing equations and boundary conditions particularly useful for studying materials processing. For mechanical and chemical engineers, and anyone already familiar with transport phenomena, Part II covers the many specific applications to materials processing, including a brief description of various materials processing technologies. Readable and unencumbered by mathematical manipulations (most of which are allocated to the appendixes), this book is also a useful text for upper-level undergraduate and graduate-level courses in materials, mechanical, and chemical engineering. It includes hundreds of photographs of materials processing in action, single and composite figures of computer simulation, handy charts for problem solving, and more. Transport Phenomena and Materials Processing: * Describes eight key materials processing technologies, including crystal growth, casting, welding, powder and fiber processing, bulk and surface heat treating, and semiconductor device fabrication * Covers the latest advances in the field, including recent results of computer simulation and flow visualization * Presents special boundary conditions for transport phenomena in materials processing * Includes charts that summarize commonly encountered boundary conditions and step-by-step procedures for problem solving * Offers a unique derivation of governing equations that leads to both overall and differential balance equations * Provides a list of publicly available computer programs and publications relevant to transport phenomena in materials processing

  3. Graphene tests of Klein phenomena

    E-print Network

    Stefano De Leo; Pietro Rotelli

    2012-02-07

    Graphene is characterized by chiral electronic excitations. As such it provides a perfect testing ground for the production of Klein pairs (electron/holes). If confirmed, the standard results for barrier phenomena must be reconsidered with, as a byproduct, the accumulation within the barrier of holes.

  4. Quantum Phenomena Observed Using Electrons

    SciTech Connect

    Tonomura, Akira [Okinawa Institute of Science and Technology, Onna-son, Okinawa 904-0412 (Japan); Advanced Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama, 350-0395 (Japan); Advanced Science Institute, RIKEN, Wako, Saitama, 351-0198 (Japan)

    2011-05-06

    Electron phase microscopy based on the Aharonov-Bohm (AB) effect principle has been used to illuminate fundamental phenomena concerning magnetism and superconductivity by visualizing quantitative magnetic lines of force. This paper deals with confirmation experiments on the AB effect, the magnetization process of tiny magnetic heads for perpendicular recording, and vortex behaviors in high-Tc superconductors.

  5. Quantum imitations of physical phenomena.

    SciTech Connect

    Ortiz, G. (Gerardo)

    2001-01-01

    Quantum imitation is an attempt to exploit quantum laws to advantage, and thus accomplish efficient simulation of physical phenomena. We discuss the fundamental concepts behind this new paradigm of information processing, such as the connection between models of computation and physical systems, along with the first imitation of a toy quantum many-body problem.

  6. Wave phenomena in phononic crystals

    Microsoft Academic Search

    Alexey Sukhovich

    2007-01-01

    Novel wave phenomena in two- and three-dimensional (2D and 3D) phononic crystals were investigated experimentally using ultrasonic techniques. These ultrasonic techniques allow the full wave field to be imaged directly, which is a considerable advantage in fundamental studies of wave propagation in periodic media. Resonant tunnelling of ultrasonic waves was successfully observed for the first time by measuring the transmission

  7. Usefulness of Simulating Social Phenomena

    Microsoft Academic Search

    Pablo Lucas

    This paper discusses 1 the current usefulness and implications of developing research on agent-based Simulation Models of Social Phenomena (SMSP) beyond purely academic, hobbyist or educational purposes. Design, development and testing phases are discussed along with issues evidence-driven modellers often face whilst collecting, analysing and translating quantitative and qualitative empirical data into social simulation models. Methodological recommendations are discussed in

  8. New atmospheric sensor analysis study

    NASA Technical Reports Server (NTRS)

    Parker, K. G.

    1989-01-01

    The functional capabilities of the ESAD Research Computing Facility are discussed. The system is used in processing atmospheric measurements which are used in the evaluation of sensor performance, conducting design-concept simulation studies, and also in modeling the physical and dynamical nature of atmospheric processes. The results may then be evaluated to furnish inputs into the final design specifications for new space sensors intended for future Spacelab, Space Station, and free-flying missions. In addition, data gathered from these missions may subsequently be analyzed to provide better understanding of requirements for numerical modeling of atmospheric phenomena.

  9. Atmospheric propagation effects relevant to optical communications

    NASA Technical Reports Server (NTRS)

    Shaik, K. S.

    1988-01-01

    A number of atmospheric phenomena affect the propagation of light. The effects of clear air turbulence are reviewed as well as atmospheric turbidity on optical communications. Among the phenomena considered are astronomical and random refraction, scintillation, beam broadening, spatial coherence, angle of arrival, aperture averaging, absorption and scattering, and the effect of opaque clouds. An extensive reference list is also provided for further study. Useful information on the atmospheric propagation of light in relation to optical deep space communications to an earth based receiving station is available, however, further data must be generated before such a link can be designed with committed performance.

  10. Atmospheric Propagation Effects Relevant to Optical Communications

    NASA Technical Reports Server (NTRS)

    Shaik, K. S.

    1988-01-01

    A number of atmospheric phenomena affect the propagation of light. This article reviews the effects of clear-air turbulence as well as atmospheric turbidity on optical communications. Among the phenomena considered are astronomical and random refraction, scintillation, beam broadening, spatial coherence, angle of arrival, aperture averaging, absorption and scattering, and the effect of opaque clouds. An extensive reference list is also provided for further study, Useful information on the atmospheric propagation of light in resolution to optical deep-space communications to an earth-based receiving station is available, however, further data must be generated before such a link can be designed with committed performance.

  11. Atmospheric effects on oblique impacts

    NASA Technical Reports Server (NTRS)

    Schultz, P. H.

    1991-01-01

    Laboratory experiments and theoretical calculations often use vertical impact angles (90 deg) in order to avoid the complicating effect of asymmetry. Nevertheless, oblique impacts represent the most likely starting condition for planetary cratering. Changing both impact angles and atmospheric pressure not only allows testing previous results for vertical impacts but also reveals phenomena whose signatures would otherwise be masked in the planetary cratering record. The laboratory studies were performed for investigating impact cratering processes. Impact angles can be increased from 0 to 90 deg in 15 deg increments while maintaining a flat target surface. Different atmospheres (nitrogen, argon, and helium) characterized the effects of both gas density and Mach number. Targets varied according to purpose. Because of the complexities in atmosphere-impactor-ejecta interactions, no single combination allows direct simulation of a planetary-scale (10-100 km) event. Nevertheless, fundamental processes and observed phenomena allow formulating first-order models at such broad scales.

  12. Transient Lunar Phenomena: Regularity and Reality

    E-print Network

    Arlin P. S. Crotts

    2007-06-27

    Transient lunar phenomena (TLPs) have been reported for centuries, but their nature is largely unsettled. A review of TLP reports shows regularities in the observations; a key question is whether this structure is imposed by human observer effects, terrestrial atmospheric effects or processes tied to the lunar surface. I interrogate an extensive TLP catalog to determine if human factors determine the distribution of TLP reports. I divide the sample according to variables which should produce varying results if determining factors involve humans e.g., historical epoch or geographical location of the observer, not reflecting phenomena tied to the lunar surface. Regardless of how we split the ample, the results are similar: ~50% of the reports involve crater Aristarchus nd vicinity, ~16% from Plato, ~6% from other recent, major impacts, plus a few at Grimaldi. Mare Crisium produces a robust signal for three of five averages of up to 7% of the reports (however, Crisium is an extended feature). The consistency in TLP report counts for specific features indicates that >~80% of reports are consistent with being real (perhaps excepting Crisium). Some commonly reported sites disappear from the robust averages, including Alphonsus, Ross D and Gassendi. TLP reports supporting these sites originate almost entirely after year 1955, when TLPs became more popular targets of observation and many more (and inexperienced) observers searched for TLPs. In a companion paper, we compare the spatial distribution of robust TLP sites of transient outgassing (seen on Apollo and Lunar Prospector). To a high confidence against the random hypothesis, robust TLP sites and those of lunar outgassing correlate strongly, further arguing for the reality of TLPs. [Abstract abridged.

  13. TRANSIENT LUNAR PHENOMENA: REGULARITY AND REALITY

    SciTech Connect

    Crotts, Arlin P. S. [Department of Astronomy, Columbia University, Columbia Astrophysics Laboratory, 550 West 120th Street, New York, NY 10027 (United States)

    2009-05-20

    Transient lunar phenomena (TLPs) have been reported for centuries, but their nature is largely unsettled, and even their existence as a coherent phenomenon is controversial. Nonetheless, TLP data show regularities in the observations; a key question is whether this structure is imposed by processes tied to the lunar surface, or by terrestrial atmospheric or human observer effects. I interrogate an extensive catalog of TLPs to gauge how human factors determine the distribution of TLP reports. The sample is grouped according to variables which should produce differing results if determining factors involve humans, and not reflecting phenomena tied to the lunar surface. Features dependent on human factors can then be excluded. Regardless of how the sample is split, the results are similar: {approx}50% of reports originate from near Aristarchus, {approx}16% from Plato, {approx}6% from recent, major impacts (Copernicus, Kepler, Tycho, and Aristarchus), plus several at Grimaldi. Mare Crisium produces a robust signal in some cases (however, Crisium is too large for a 'feature' as defined). TLP count consistency for these features indicates that {approx}80% of these may be real. Some commonly reported sites disappear from the robust averages, including Alphonsus, Ross D, and Gassendi. These reports begin almost exclusively after 1955, when TLPs became widely known and many more (and inexperienced) observers searched for TLPs. In a companion paper, we compare the spatial distribution of robust TLP sites to transient outgassing (seen by Apollo and Lunar Prospector instruments). To a high confidence, robust TLP sites and those of lunar outgassing correlate strongly, further arguing for the reality of TLPs.

  14. Very Low Frequency (VLF) studies of Ionospheric\\/Magnetospheric Electromagnetic phenomena in Indian Low Latitude Region using AWESOME Receivers

    Microsoft Academic Search

    R. Singh; B. Veenadhari; S. Alex

    2006-01-01

    Ground based observations of whistler mode ELF\\/VLF (300 Hz 30 kHz) waves are considered as an important remote sensing tool for the investigation of upper atmosphere and magnetosphere. These VLF waves find their origin in various natural and artificial phenomena, the natural sources include thunderstorms, lightning and associated phenomena. Despite of the fact that conjugate region of India having less

  15. Emergent Phenomena via Molecular Dynamics

    NASA Astrophysics Data System (ADS)

    Rapaport, D. C.

    Emergent phenomena are unusual because they are not obvious consequences of the design of the systems in which they appear, a feature no less relevant when they are being simulated. Several systems that exhibit surprisingly rich emergent behavior, each studied by molecular dynamics (MD) simulation, are described: (i) Modeling self-assembly processes associated with virus growth reveals the ability to achieve error-free assembly, where paradoxically, near-maximum yields are due to reversible bond formation. (ii) In fluids studied at the atomistic level, complex hydrodynamic phenomena in rotating and convecting fluids - the Taylor- Couette and Rayleigh-Bénard instabilities - can be reproduced, despite the limited length and time scales accessible by MD. (iii) Segregation studies of granular mixtures in a rotating drum reproduce the expected, but counterintuitive, axial and radial segregation, while for the case of a vertically vibrated layer a novel form of horizontal segregation is revealed.

  16. Undergraduates Understanding of Cardiovascular Phenomena

    NSDL National Science Digital Library

    PhD Joel A. Michael (Rush Medical College Department of Molecular Biophysics and Physiology)

    2002-06-01

    Undergraduates students in 12 courses at 8 different institutions were surveyed to determine the prevalence of 13 different misconceptions (conceptual difficulties) about cardiovascular function. The prevalence of these misconceptions ranged from 20 to 81% and, for each misconception, was consistent across the different student populations. We also obtained explanations for the studentsÂ? answers either as free responses or with follow-up multiple-choice questions. These results suggest that students have a number of underlying conceptual difficulties about cardiovascular phenomena. One possible source of some misconceptions is the studentsÂ? inability to apply simple general models to specific cardiovascular phenomena. Some implications of these results for teachers of physiology are discussed.

  17. Statistical phenomena in particle beams

    SciTech Connect

    Bisognano, J.J.

    1984-09-01

    Particle beams are subject to a variety of apparently distinct statistical phenomena such as intrabeam scattering, stochastic cooling, electron cooling, coherent instabilities, and radiofrequency noise diffusion. In fact, both the physics and mathematical description of these mechanisms are quite similar, with the notion of correlation as a powerful unifying principle. In this presentation we will attempt to provide both a physical and a mathematical basis for understanding the wide range of statistical phenomena that have been discussed. In the course of this study the tools of the trade will be introduced, e.g., the Vlasov and Fokker-Planck equations, noise theory, correlation functions, and beam transfer functions. Although a major concern will be to provide equations for analyzing machine design, the primary goal is to introduce a basic set of physical concepts having a very broad range of applicability.

  18. New phenomena searches at CDF

    SciTech Connect

    Soha, Aron; /UC, Davis

    2006-04-01

    The authors report on recent results from the Collider Detector at Fermilab (CDF) experiment, which is accumulating data from proton-antiproton collisions with {radical}s = 1.96 TeV at Run II of the Fermilab Tevatron. The new phenomena being explored include Higgs, Supersymmetry, and large extra dimensions. They also present the latest results of searches for heavy objects, which would indicate physics beyond the Standard Model.

  19. Neural Correlates of Insight Phenomena

    Microsoft Academic Search

    Jing Luo; Gunther Knoblich; Chongde Lin

    2009-01-01

    Difficult problems are sometimes solved in a sudden flash of illumination, a phenomenon referred to as “insight.” Recent neuroimaging\\u000a studies have begun to reveal the neural correlates of the cognitive processes underlying such insight phenomena (Luo and Niki\\u000a 2003; Jung-Beeman et al. 2004; Luo et al. 2004a, 2006; Mai et al. 2004; Lang et al. 2006). However, researchers have encountered

  20. REVIEW ARTICLE: Valence fluctuation phenomena

    Microsoft Academic Search

    J. M. Lawrence; P. S. Riseborough; R. D. Parks

    1981-01-01

    Valence fluctuation phenomena occur in rare-earth compounds in which the proximity of the 4f level to the Fermi energy leads to instabilities of the charge configuration (valence) and\\/or of the magnetic moment. The authors review the experimental results observed in the subset of such systems for which the 4f ions form a lattice with identical valence on each site. The

  1. Insulation Phenomena of Compressed Air

    Microsoft Academic Search

    L. D. McConnell

    1957-01-01

    Test data on impulse and 60-cycle voltage breakdown strength for compressed air with various electrode configurations are reported. The tests were made with rod-to-plane electrodes with spacings up to 8 inches and pressures to 250 psig (pounds per square inch gage). Breakdown phenomena of air insulation encountered in the development of an air insulated air-blast circuit breaker1 are reported. The

  2. An investigation of relationships between meso- and synoptic-scale phenomena 

    E-print Network

    Wood, James Eugene

    1971-01-01

    (radar echoes) may be present. The best association between meso- and synoptic-scale phenomena was found for a December situation when synoptic-scale systems were well developed. A good association between meso- and synoptic-scale events also... in which The citations on the following pages follow the style of the Journal of A lied Meteorolo mesoscale systems, the existence of which is inferred from radar echoes, should be present. ~Ek d t th P bl Nesoscale systems are atmospheric phenomena...

  3. Analysis of atmospheric delays and asymmetric positioning errors in the global positioning system

    E-print Network

    Materna, Kathryn

    2014-01-01

    Abstract Errors in modeling atmospheric delays are one of the limiting factors in the accuracy of GPS position determination. In regions with uneven topography, atmospheric delay phenomena can be especially complicated. ...

  4. Convective storms in planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Hueso, R.; Sánchez-Lavega, A.

    2013-05-01

    The atmospheres of the planets in the Solar System have different physical properties that in some cases can be considered as extreme when compared with our own planet's more familiar atmosphere. From the tenuous and cold atmosphere of Mars to the dense and warm atmosphere of Venus in the case of the terrestrial planets, to the gigantic atmospheres of the outer planets, or the nitrogen and methane atmosphere of Saturn's moon Titan, we can find a large variety of physical environments. The comparative study of these atmospheres provides a better understanding of the physics of a geophysical fluid. In many of these worlds convective storms of different intensity appear. They are analogous to terrestrial atmospheres fed by the release of latent heat when one of the gases in the atmosphere condenses and they are therefore called moist convective storms. In many of these planets they can produce severe meteorological phenomena and by studying them in a comparative way we can aspire to get a further insight in the dynamics of these atmospheres even beyond the scope of moist convection. A classical example is the structure of the complex systems of winds in the giant planets Jupiter and Saturn. These winds are zonal and alternate in latitude but their deep structure is not accessible to direct observation. However the behaviour of large--scale convective storms vertically extending over the "weather layer" allows to study the buried roots of these winds. Another interesting atmosphere with a rather different structure of convection is Titan, a world where methane is close to its triple point in the atmosphere and can condense in bright clouds with large precipitation fluxes that may model part of the orography of the surface making Titan a world with a methane cycle similar to the hydrological cycle of Earth's atmosphere.

  5. Irradiation-induced phenomena in carbon

    E-print Network

    Krasheninnikov, Arkady V.

    Chapter 1 Irradiation-induced phenomena in carbon nanotubes To appear in "Chemistry of Carbon@acclab.helsinki.fi 1 #12;2CHAPTER 1. IRRADIATION-INDUCED PHENOMENA IN CARBON NANOTUBES #12;Contents 1 Irradiation-induced phenomena in carbon nanotubes 1 1.1 Introduction

  6. Groundwater phenomena and the theory of mixtures

    SciTech Connect

    Lee, D.W. (Oak Ridge National Lab., TN (USA)); Wineman, A.S. (Michigan Univ., Ann Arbor, MI (USA). Dept. of Mechanical Engineering and Applied Mechanics)

    1991-01-01

    The phenomena of groundwater motion and the recent developments in the Theory of Mixtures are reviewed. Comparisons of these results with those from classical theory are presented. Phenomena of interest that are not well explained are discussed and the potential of the Theory of Mixtures in addressing these phenomena is presented. 16 refs.

  7. Multifractal phenomena in physics and chemistry

    Microsoft Academic Search

    H. Eugene Stanley; Paul Meakin

    1988-01-01

    A brief introduction to multifractal phenomena, different regions of an object that have different fractal properties, is given. The application of the concept of multifractal phenomena to complex surfaces and interfaces and to fluid flow in porous media is discussed. Analogies of multifractals with thermodynamics and multifractal scaling are pointed out. The association of multifractal phenomena with systems where the

  8. Correlated randomness and switching phenomena

    NASA Astrophysics Data System (ADS)

    Stanley, H. E.; Buldyrev, S. V.; Franzese, G.; Havlin, S.; Mallamace, F.; Kumar, P.; Plerou, V.; Preis, T.

    2010-08-01

    One challenge of biology, medicine, and economics is that the systems treated by these serious scientific disciplines have no perfect metronome in time and no perfect spatial architecture-crystalline or otherwise. Nonetheless, as if by magic, out of nothing but randomness one finds remarkably fine-tuned processes in time and remarkably fine-tuned structures in space. Further, many of these processes and structures have the remarkable feature of “switching” from one behavior to another as if by magic. The past century has, philosophically, been concerned with placing aside the human tendency to see the universe as a fine-tuned machine. Here we will address the challenge of uncovering how, through randomness (albeit, as we shall see, strongly correlated randomness), one can arrive at some of the many spatial and temporal patterns in biology, medicine, and economics and even begin to characterize the switching phenomena that enables a system to pass from one state to another. Inspired by principles developed by A. Nihat Berker and scores of other statistical physicists in recent years, we discuss some applications of correlated randomness to understand switching phenomena in various fields. Specifically, we present evidence from experiments and from computer simulations supporting the hypothesis that water’s anomalies are related to a switching point (which is not unlike the “tipping point” immortalized by Malcolm Gladwell), and that the bubbles in economic phenomena that occur on all scales are not “outliers” (another Gladwell immortalization). Though more speculative, we support the idea of disease as arising from some kind of yet-to-be-understood complex switching phenomenon, by discussing data on selected examples, including heart disease and Alzheimer disease.

  9. Magnetism as the emergent phenomena

    NASA Astrophysics Data System (ADS)

    Tokura, Yoshinori

    2014-03-01

    Versatile emergent phenomena have been observed in strongly correlated electron systems as a consequence of mutual strong coupling among the spin, orbital, and charge degrees of freedom. Here, we would overview the outcomes of topological spin textures in transport, dielectric, and optical properties of correlated systems; these include sciences of colossal magnetoresistance, multiferroics, skyrmions, and topological/quantum-anomalous Hall effects. Impacts of the emergent electric and magnetic fields acting on the electrons in a solid are discussed as well as their possible applications to future devices.

  10. Quantum phenomena in gravitational field

    NASA Astrophysics Data System (ADS)

    Bourdel, Th.; Doser, M.; Ernest, A. D.; Voronin, A. Yu.; Voronin, V. V.

    2011-10-01

    The subjects presented here are very different. Their common feature is that they all involve quantum phenomena in a gravitational field: gravitational quantum states of ultracold antihydrogen above a material surface and measuring a gravitational interaction of antihydrogen in AEGIS, a quantum trampoline for ultracold atoms, and a hypothesis on naturally occurring gravitational quantum states, an Eötvös-type experiment with cold neutrons and others. Considering them together, however, we could learn that they have many common points both in physics and in methodology.

  11. Gravitational anomaly and transport phenomena.

    PubMed

    Landsteiner, Karl; Megías, Eugenio; Pena-Benitez, Francisco

    2011-07-01

    Quantum anomalies give rise to new transport phenomena. In particular, a magnetic field can induce an anomalous current via the chiral magnetic effect and a vortex in the relativistic fluid can also induce a current via the chiral vortical effect. The related transport coefficients can be calculated via Kubo formulas. We evaluate the Kubo formula for the anomalous vortical conductivity at weak coupling and show that it receives contributions proportional to the gravitational anomaly coefficient. The gravitational anomaly gives rise to an anomalous vortical effect even for an uncharged fluid. PMID:21797593

  12. Uranium Pyrophoricity Phenomena and Prediction

    SciTech Connect

    DUNCAN, D.R.

    2000-04-20

    We have compiled a topical reference on the phenomena, experiences, experiments, and prediction of uranium pyrophoricity for the Hanford Spent Nuclear Fuel Project (SNFP) with specific applications to SNFP process and situations. The purpose of the compilation is to create a reference to integrate and preserve this knowledge. Decades ago, uranium and zirconium fires were commonplace at Atomic Energy Commission facilities, and good documentation of experiences is surprisingly sparse. Today, these phenomena are important to site remediation and analysis of packaging, transportation, and processing of unirradiated metal scrap and spent nuclear fuel. Our document, bearing the same title as this paper, will soon be available in the Hanford document system [Plys, et al., 2000]. This paper explains general content of our topical reference and provides examples useful throughout the DOE complex. Moreover, the methods described here can be applied to analysis of potentially pyrophoric plutonium, metal, or metal hydride compounds provided that kinetic data are available. A key feature of this paper is a set of straightforward equations and values that are immediately applicable to safety analysis.

  13. S-290 Unit 6: Atmospheric Stability

    NSDL National Science Digital Library

    COMET

    2010-03-02

    S-290 Unit 6: Atmospheric Stability introduces the processes related to stable and unstable atmospheric conditions and explains their impact on fire behavior. This Unit provides detailed information about how fire behavior is affected by stable and unstable atmospheric phenomena such as inversions and thunderstorms. The Unit also explains cloud formation and describes the usage of clouds and other visual indicators to recognize stable and unstable atmospheric conditions. The module is part of the Intermediate Wildland Fire Behavior Course "http://www.meted.ucar.edu/dl_courses/S290".

  14. Carbon dioxide opacity of the Venus' atmosphere

    NASA Astrophysics Data System (ADS)

    Snels, Marcel; Stefani, Stefania; Grassi, Davide; Piccioni, Giuseppe; Adriani, Alberto

    2014-11-01

    Venus' atmosphere consists of about 95% of carbon dioxide, which accounts for most of the absorption of the radiation emitted by its hot surface. The large densities and high temperatures of Venus' atmosphere make the absorption much more complex than for low density atmospheres such as Earth or Mars. Available experimental data are at present insufficient and theoretical models inadequate to describe complex absorption line shapes and collision-induced phenomena. Here we present a survey of all absorption and scattering processes which influence the transparency of Venus' atmosphere for what concerns carbon dioxide.

  15. Infrared experiments for spaceborne planetary atmospheres research. Full report

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The role of infrared sensing in atmospheric science is discussed and existing infrared measurement techniques are reviewed. Proposed techniques for measuring planetary atmospheres are criticized and recommended instrument developments for spaceborne investigations are summarized for the following phenomena: global and local radiative budget; radiative flux profiles; winds; temperature; pressure; transient and marginal atmospheres; planetary rotation and global atmospheric activity; abundances of stable constituents; vertical, lateral, and temporal distribution of abundances; composition of clouds and aerosols; radiative properties of clouds and aerosols; cloud microstructure; cloud macrostructure; and non-LTE phenomena.

  16. Atmospheric studies payloads. [space shuttle borne optical facility

    NASA Technical Reports Server (NTRS)

    Hudson, R. D.

    1973-01-01

    Several proposed Shuttle payloads for studying atmospheric phenomena and structure are discussed, with particular reference to a concept being developed for an optical facility. The payloads are put together of instruments both for in-situ measurements and for remote sensing of atmospheric emission, scattering, and absorption, using active and passive optical elements. Studies may include the artificial perturbation of the upper atmosphere with vapor releases or high powered UV lasers. The major areas of research in atmospheric physics are outlined, along with the parameters and phenomena of interest and the measurement techniques most frequently employed.

  17. 48 Optical Illusions & Visual Phenomena

    NSDL National Science Digital Library

    Have you ever wondered how different optical illusions work? This fun, informative, and very cool website developed by ophthalmologist Dr. Michael Bach of the University of Freiburg's Medical School introduces 48 interactive visual illusions and phenomena. The illusions are animated and accompanied by explanations that help visitors make sense of their perceptual responses. Major illusion categories include: Motion & Time, Luminance & Contrast, Colour, Cognitive, and more. The site is still in progress, and Dr. Bach encourages both general feedback, and additional scientific information for improving the illusion explanations. The second site, also from Professor Bach, presents site users with an interactive, online Visual Acuity Test. Note: The Contrast component of the Test has yet to be implemented.

  18. Applications of speckle phenomena; Proceedings of the Seminar, San Diego, CA, July 29, 30, 1980

    Microsoft Academic Search

    W. H. Carter

    1980-01-01

    Topics discussed include the basic properties of speckle phenomena in imaging, in information processing, and in wavelength diversity, stellar speckle interferometry, and speckle metrology. Papers are presented on speckle propagation through the turbulent atmosphere, digital processing of images in speckle noise, observational speckle interferometry, and astronomical imaging by processing stellar speckle interferometry data. Attention is also given to speckle in

  19. Atmospheric dust

    NSDL National Science Digital Library

    University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

    2003-01-01

    What is the purpose of dust in the atmosphere? On this activity page, part of an interactive laboratory series for grades 8-12, students read about the need for dust in the atmosphere as an agent for condensation. The addition of dust particles to the atmosphere by airplanes introduces students to the concept of cloud seeding and influencing the chance of rain in an area. Copyright 2005 Eisenhower National Clearinghouse

  20. Pluto's atmosphere

    SciTech Connect

    Elliot, J.L.; Dunham, E.W.; Bosh, A.S.; Slivan, S.M.; Young, L.A.

    1989-01-01

    Airborne CCD photometer observations of Pluto's June 9, 1988 stellar occultation have yielded an occultation lightcurve, probing two regions on the sunrise limb 2000 km apart, which reveals an upper atmosphere overlying an extinction layer with an abrupt upper boundary. The extinction layer may surround the entire planet. Attention is given to a model atmosphere whose occultation lightcurve closely duplicates observations; fits of the model to the immersion and emersion lightcurves exhibit no significant derived atmosphere-structure differences. Assuming a pure methane atmosphere, surface pressures of the order of 3 microbars are consistent with the occultation data. 43 references.

  1. Nucleation phenomena in polymeric systems

    NASA Astrophysics Data System (ADS)

    Binder, K.

    1995-02-01

    Materials formed from long flexible macromolecules differ from their small-molecule analogs, because corresponding collective length scales are distinctly larger and many dynamical phenomena are very much slower; in addition, the variation of chain length N yields a control parameter that leaves intermolecular forces invariant, but allows a stringent test of theories. These concepts are exemplified in a discussion of nucleation barriers for symmetrical polymer ( A, B)-mixtures (chain lengths NA = NB = N) near the critical temperature Tc, and for symmetrical block copolymers near the (fluctuation-induced) first order transition between the disordered melt and the lamellar mesophase. While in the latter case for N ? ? the transition becomes second-order and the order of magnitude of the nucleation barrier vanishes as N - {1}/{3}, for the polymer mixtures it increases as N {1}/{2} in the mean-field critical regime. Experiments and simulations, however, both show that very long chains are needed to fully reach this mean-field critical regime. For asymmetrical block copolymers {f= {N A}/{(N A+ N) }? {1}/{2}} the nucleation barrier scales as N {1}/{2}|f- {1}/{2}| 5.

  2. Bleed Hole Flow Phenomena Studied

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Boundary-layer bleed is an invaluable tool for controlling the airflow in supersonic aircraft engine inlets. Incoming air is decelerated to subsonic speeds prior to entering the compressor via a series of oblique shocks. The low momentum flow in the boundary layer interacts with these shocks, growing in thickness and, under some conditions, leading to flow separation. To remedy this, bleed holes are strategically located to remove mass from the boundary layer, reducing its thickness and helping to maintain uniform flow to the compressor. The bleed requirements for any inlet design are unique and must be validated by extensive wind tunnel testing to optimize performance and efficiency. To accelerate this process and reduce cost, researchers at the NASA Lewis Research Center initiated an experimental program to study the flow phenomena associated with bleed holes. Knowledge of these flow properties will be incorporated into computational fluid dynamics (CFD) models that will aid engine inlet designers in optimizing bleed configurations before any hardware is fabricated. This ongoing investigation is currently examining two hole geometries, 90 and 20 (both with 5-mm diameters), and various flow features.

  3. Interference Phenomena in Quantum Information

    E-print Network

    Martin Stefanak

    2010-09-01

    One of the key features of quantum mechanics is the interference of probability amplitudes. The reason for the appearance of interference is mathematically very simple. It is the linear structure of the Hilbert space which is used for the description of quantum systems. In terms of physics we usually talk about the superposition principle valid for individual and composed quantum objects. So, while the source of interference is understandable it leads in fact to many counter-intuitive physical phenomena which puzzle physicists for almost hundred years. The present thesis studies interference in two seemingly disjoint fields of physics. However, both have strong links to quantum information processing and hence are related. In the first part we study the intriguing properties of quantum walks. In the second part we analyze a sophisticated application of wave packet dynamics in atoms and molecules for factorization of integers. The main body of the thesis is based on the original contributions listed separately at the end of the thesis. The more technical aspects and brief summaries of used methods are left for appendices.

  4. WESF natural phenomena hazards survey

    SciTech Connect

    Wagenblast, G.R., Westinghouse Hanford

    1996-07-01

    A team of engineers conducted a systematic natural hazards phenomena (NPH) survey for the 225-B Waste Encapsulation and Storage Facility (WESF). The survey is an assessment of the existing design documentation to serve as the structural design basis for WESF, and the Interim Safety Basis (ISB). The lateral force resisting systems for the 225-B building structures, and the anchorages for the WESF safety related systems were evaluated. The original seismic and other design analyses were technically reviewed. Engineering judgment assessments were made of the probability of NPH survival, including seismic, for the 225-B structures and WESF safety systems. The method for the survey is based on the experience of the investigating engineers,and documented earthquake experience (expected response) data.The survey uses knowledge on NPH performance and engineering experience to determine the WESF strengths for NPH resistance, and uncover possible weak links. The survey, in general, concludes that the 225-B structures and WESF safety systems are designed and constructed commensurate with the current Hanford Site design criteria.

  5. Pluto's atmosphere

    Microsoft Academic Search

    J. L. Elliot; E. W. Dunham; A. S. Bosh; S. M. Slivan; L. A. Young

    1989-01-01

    Airborne CCD photometer observations of Pluto's June 9, 1988 stellar occultation have yielded an occultation lightcurve, probing two regions on the sunrise limb 2000 km apart, which reveals an upper atmosphere overlying an extinction layer with an abrupt upper boundary. The extinction layer may surround the entire planet. Attention is given to a model atmosphere whose occultation lightcurve closely duplicates

  6. The Atmosphere.

    ERIC Educational Resources Information Center

    Ingersoll, Andrew P.

    1983-01-01

    The composition and dynamics of the earth's atmosphere are discussed, considering the atmosphere's role in distributing the energy of solar radiation received by the earth. Models of this activity which help to explain climates of the past and predict those of the future are also considered. (JN)

  7. Ranking significant phenomena in physical systems

    Microsoft Academic Search

    R. A. Dimenna; T. K. Larson

    1989-01-01

    The analysis of any physical system requires a thorough understanding of the principal phenomena affecting the behavior of that system. In a complex application such as a nuclear reactor, identifying the principal phenomena in an accident transient can be a formidable task. This paper describes the use of the analytical hierarchy process (AHP) to assimilate engineering judgments that relate and

  8. Thermoelectric phenomena via an interacting particle system

    E-print Network

    Maes, Christian

    Thermoelectric phenomena via an interacting particle system Christian Maes and Maarten H. van for thermoelectric phenomena in terms of an interacting particle system, a lattice electron gas dynamics, a standard reference is [1]. We present an interacting particle system for the standard thermoelectric

  9. Stochastic properties of partial-discharge phenomena

    Microsoft Academic Search

    R. J. Van Brunt

    1991-01-01

    The author presents a bibliography and survey of the literature concerned with theory and measurement of the stochastic behavior of pulsating partial-discharge (PD) phenomena that can occur when insulation is subjected to electrical stress. The types of PD phenomena considered include AC and DC generated electron avalanches, pulsating positive and negative corona in gases, and PD that occur in liquid

  10. Critical Phenomena in Multi-scale Models

    Microsoft Academic Search

    E. A. Shchepakina; V. A. Sobolev

    The paper is devoted to the investigation of the relationship between slow integral manifolds of singularly perturbed dierential equations and critical phenomena in chemical kinetics and laser models. We tried to consider dierent problems using the techniques of canards and black swans. The mathematical language of singular perturbations seems to apply to all critical phenomena even in the most disparate

  11. Exoplanetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Madhusudhan, N.; Knutson, H.; Fortney, J. J.; Barman, T.

    The study of exoplanetary atmospheres is one of the most exciting and dynamic frontiers in astronomy. Over the past two decades ongoing surveys have revealed an astonishing diversity in the planetary masses, radii, temperatures, orbital parameters, and host stellar properties of exoplanetary systems. We are now moving into an era where we can begin to address fundamental questions concerning the diversity of exoplanetary compositions, atmospheric and interior processes, and formation histories, just as have been pursued for solar system planets over the past century. Exoplanetary atmospheres provide a direct means to address these questions via their observable spectral signatures. In the last decade, and particularly in the last five years, tremendous progress has been made in detecting atmospheric signatures of exoplanets through photometric and spectroscopic methods using a variety of spaceborne and/or groundbased observational facilities. These observations are beginning to provide important constraints on a wide gamut of atmospheric properties, including pressure-temperature profiles, chemical compositions, energy circulation, presence of clouds, and nonequilibrium processes. The latest studies are also beginning to connect the inferred chemical compositions to exoplanetary formation conditions. In the present chapter, we review the most recent developments in the area of exoplanetary atmospheres. Our review covers advances in both observations and theory of exoplanetary atmospheres, and spans a broad range of exoplanet types (gas giants, ice giants, and super-Earths) and detection methods (transiting planets, direct imaging, and radial velocity). A number of upcoming planet-finding surveys will focus on detecting exoplanets orbiting nearby bright stars, which are the best targets for detailed atmospheric characterization. We close with a discussion of the bright prospects for future studies of exoplanetary atmospheres.

  12. Atmospheric Mass

    NSDL National Science Digital Library

    This is a lesson about the amount of atmosphere a planet is likely to have. Learners will look for the relationship between atmospheric mass and other characteristics of the planet. When the results are not completely conclusive, the students explore possible causes of discrepancies in the data. They conclude that gravity, mass and diameter all have a role in determining atmospheric mass. The lesson models scientific inquiry using the 5E instructional model and includes teacher notes, prerequisite concepts, common misconceptions, student journal and reading. This is lesson 11 in the Astro-Venture Astronomy Unit. The lessons are designed for educators to use in conjunction with the Astro-Venture multimedia modules.

  13. Wave phenomena in phononic crystals

    NASA Astrophysics Data System (ADS)

    Sukhovich, Alexey

    Novel wave phenomena in two- and three-dimensional (2D and 3D) phononic crystals were investigated experimentally using ultrasonic techniques. These ultrasonic techniques allow the full wave field to be imaged directly, which is a considerable advantage in fundamental studies of wave propagation in periodic media. Resonant tunnelling of ultrasonic waves was successfully observed for the first time by measuring the transmission of ultrasound pulses through a double barrier consisting of two 3D phononic crystals separated by a cavity. This effect is the classical analogue of resonant tunnelling of a quantum mechanical particle through a double potential barrier, in which transmission reaches unity at resonant frequencies. For phononic crystals, the tunnelling peak was found to be less than unity, an effect that was explained by absorption. Absorption introduces a small propagating component inside the crystals in addition to the dominant evanescent mode at band gap frequencies, and causes leakage of the pulse from the cavity. The dynamics of resonant tunnelling was explored by measuring the group velocities of the ultrasonic pulses. Very slow and very fast velocities were found at frequencies close to and at the resonance, respectively. These extreme values are less than the speed of sound in air and greater than the speed of sound in any of the crystal's constituent materials. Negative refraction and focusing effects in 2D phononic crystals were also observed. Negative refraction of ultrasound was demonstrated unambiguously in a prism-shaped 2D crystal at frequencies in the 2nd pass band, where the equifrequency contours are circular so that the wave vector and group velocity are antiparallel. The Multiple Scattering Theory and Snell's law allowed theoretical predictions of the refraction angles. Excellent agreement was found between theory and experiment. The negative refraction experiments revealed a mechanism that can be used to focus ultrasound using a flat phononic crystal, and experiments to demonstrate the focusing of ultrasound emitted by several point sources were successfully carried out. The importance of using phononic crystals with circular equi frequency contours, as well as matching the size of the contours inside and outside the crystal, was established. Both conditions were satisfied by a flat phononic crystal of steel rods, in which the liquid inside the crystal (methanol) was different from the outside medium (water). The possibility of achieving subwavelength resolution using this phononic crystal was investigated with a subwavelength line source (a miniature strip-shaped transducer, approximately lambda/5 wide). A resolution of 0.55lambda was found, which is just above the diffraction limit lambda/2.

  14. Earth's Atmosphere

    NSDL National Science Digital Library

    2012-08-03

    This problem set is about the methods scientists use to compare the abundance of the different elements in Earth's atmosphere. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

  15. Exoplanet Atmospheres

    E-print Network

    Seager, Sara

    At the dawn of the first discovery of exoplanets orbiting Sun-like stars in the mid-1990s, few believed that observations of exoplanet atmospheres would ever be possible. After the 2002 Hubble Space Telescope detection of ...

  16. Exoplanetary Atmospheres

    E-print Network

    Madhusudhan, Nikku; Fortney, Jonathan; Barman, Travis

    2014-01-01

    The study of exoplanetary atmospheres is one of the most exciting and dynamic frontiers in astronomy. Over the past two decades ongoing surveys have revealed an astonishing diversity in the planetary masses, radii, temperatures, orbital parameters, and host stellar properties of exoplanetary systems. We are now moving into an era where we can begin to address fundamental questions concerning the diversity of exoplanetary compositions, atmospheric and interior processes, and formation histories, just as have been pursued for solar system planets over the past century. Exoplanetary atmospheres provide a direct means to address these questions via their observable spectral signatures. In the last decade, and particularly in the last five years, tremendous progress has been made in detecting atmospheric signatures of exoplanets through photometric and spectroscopic methods using a variety of space-borne and/or ground-based observational facilities. These observations are beginning to provide important constraints...

  17. Atmospheric pollution

    SciTech Connect

    Pickett, E.E.

    1987-01-01

    Atmospheric pollution (AP), its causes, and measures to prevent or reduce it are examined in reviews and reports presented at a workshop held in Damascus, Syria in August 1985. Topics discussed include AP and planning studies, emission sources, pollutant formation and transformation, AP effects on man and vegetation, AP control, atmospheric dispersion mechanisms and modeling, sampling and analysis techniques, air-quality monitoring, and applications. Diagrams, graphs, and tables of numerical data are provided.

  18. Atmospheric Deposition

    Microsoft Academic Search

    Kathleen C. Weathers; Alexandra G. Ponette-González

    \\u000a Atmospheric deposition plays a key role in the biogeochemistry of temperate, tropical, and boreal forests. Many essential\\u000a macro- and micronutrients as well as pollutants are delivered from the atmosphere to forest ecosystems: (1) dissolved in rain\\u000a and snow (wet deposition); (2) directly as particles and gases (dry deposition); and (3) dissolved in cloud droplets (cloud,\\u000a occult, or fog deposition, hereafter

  19. Atmospheric Dust

    NSDL National Science Digital Library

    Millions of tons of dust are lifted from deserts annually, suspended in the atmosphere, and released to fall on the oceans, but scientists are a long way from understanding the impact of atmospheric dust on the climate and weather systems of Earth or on marine organisms. This radio broadcast explains how the nitrogen, phosphorus and iron released from dust boosts the growth of phytoplankton, which also soak up carbon dioxide and release more gases into the atmosphere. Better monitoring and more sophisticated sensors are giving us a more accurate picture of the dust in the atmosphere; the broadcast reports on investigations of dust from ice cores and on computer simulations of the connections between dust and climate. But the unpredictable nature of dust events makes it extremely difficult to determine their impact on the natural systems of Earth. There are discussions with geographers, oceanographers, environmentalists and climate modelers about atmospheric dust, one of the least understood and most contradictory components of the atmosphere. The broadcast is 28 minutes in length.

  20. Synchronization Phenomena and Epoch Filter of Electroencephalogram

    NASA Astrophysics Data System (ADS)

    Matani, Ayumu

    Nonlinear electrophysiological synchronization phenomena in the brain, such as event-related (de)synchronization, long distance synchronization, and phase-reset, have received much attention in neuroscience over the last decade. These phenomena contain more electrical than physiological keywords and actually require electrical techniques to capture with electroencephalography (EEG). For instance, epoch filters, which have just recently been proposed, allow us to investigate such phenomena. Moreover, epoch filters are still developing and would hopefully generate a new paradigm in neuroscience from an electrical engineering viewpoint. Consequently, electrical engineers could be interested in EEG once again or from now on.

  1. Ambroise August Liébeault and psychic phenomena.

    PubMed

    Alvarado, Carlos S

    2009-10-01

    Some nineteenth-century hypnosis researchers did not limit their interest to the study of the conventional psychological and behavioral aspects of hypnosis, but also studied and wrote about psychic phenomena such as mental suggestion and clairvoyance. One example, and the topic of this paper, was French physician Ambroise August Liébeault (1823-1904), who influenced the Nancy school of hypnosis. Liébeault wrote about mental suggestion, clairvoyance, mediumship, and even so-called poltergeists. Some of his writings provide conventional explanations of the phenomena. Still of interest today, Liébeault's writings about psychic phenomena illustrate the overlap that existed during the nineteenth-century between hypnosis and psychic phenomena--an overlap related to the potentials of the mind and its subconscious activity. PMID:19862897

  2. Reproductive phenomena of a sexual buffelgrass plant

    E-print Network

    Taliaferro, Charles Millard

    1965-01-01

    lines apomictic lines. 21 22 REPRODUCTIVE PHENOMENA OF A SEXUAL BUFFELGRASS PLANT INTRODUCTION Buffelgrass, Pennisetum ciliare (L. ) Link, is a polymorphic, perennial, warm-season, bunch grass with a native range extending from Africa to India...

  3. Perspective: Emergent magnetic phenomena at interfaces

    NASA Astrophysics Data System (ADS)

    Suzuki, Yuri

    2015-06-01

    The discovery of emergent magnetic phenomena is of fundamental and technological interest. This perspective highlights recent promising examples of emergent ferromagnetism at complex oxide interfaces in the context of spin based electronics.

  4. Fractal Geometry and Spatial Phenomena A Bibliography

    E-print Network

    California at Santa Barbara, University of

    Fractal Geometry and Spatial Phenomena A Bibliography January 1991 Mark MacLennan, A. Stewart. MEASUREMENT ISSUES........................................................... 8 II.1 ESTIMATION OF FRACTAL DIMENSION - GENERAL ISSUES .......... 8 II.2 ESTIMATION OF FRACTAL DIMENSION FOR CURVES/PROFILES ... 9 II.3

  5. Effects of hydrodynamics and thermal radiation in the atmosphere after comet impacts

    Microsoft Academic Search

    I. V. Nemchinov; M. P. Popova; L. P. Shubadeeva; V. V. Shuvalov; V. V. Svetsov

    1993-01-01

    Radiation phenomena in the atmosphere after impacts of cosmic bodies have special features in comparison with the surface nuclear explosions. First, initial concentration of energy after the impact is lower, and second, a wake after the passage of the meteoroid through the atmosphere has a dramatic effect on the atmospheric flow and radiation transfer. Consequently, scaling laws can not be

  6. Atmospheric radiation

    SciTech Connect

    Harshvardhan, M.R. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

    1991-01-01

    Studies of atmospheric radiative processes are summarized for the period 1987-1990. Topics discussed include radiation modeling; clouds and radiation; radiative effects in dynamics and climate; radiation budget and aerosol effects; and gaseous absorption, particulate scattering and surface reflection. It is concluded that the key developments of the period are a defining of the radiative forcing to the climate system by trace gases and clouds, the recognition that cloud microphysics and morphology need to be incorporated not only into radiation models but also climate models, and the isolation of a few important unsolved theoretical problems in atmospheric radiation.

  7. Atmospheric Chemistry

    NSDL National Science Digital Library

    This set of links provides access to resources on atmospheric chemistry, especially acid deposition, air pollution, and air quality. The sites include personal and government pages, universities and research groups, non-governmental organizations and meetings, and products and services. There are also links to related search topics.

  8. Partial-Discharge Phenomena and the Effect of Their Constituents on Polyethylene

    Microsoft Academic Search

    Christian Mayoux

    1976-01-01

    A method of investigating partial-discharge phenomena andtheir effect on polyethylene is described. A physical study was carriedout with air at atmospheric pressure and gaps between 2 and 14 mm.It is shown, that with this range of gaps and with dielectric walls, astreamer process appears as in the case of a positive point and a metallicplane.The evolution of the polyethylene samples

  9. Lidar measurements of atmospheric constituents

    NASA Astrophysics Data System (ADS)

    Weitkamp, Klaus C. H.

    1996-12-01

    The advent of depth-resolving, remote measurement techniques for the determination of atmospheric constituents added a new dimension to the investigation of atmospheric phenomena. In this paper optical, or lidar, techniques suited for this purpose are reviewed. After a presentation of the processes used and the algorithms necessary to extract the interesting information from the optical return signals, a few considerations about the necessary instrumentation are presented. For illustration, one example is shown of results obtained with elastic backscatter, differential absorption and scattering. Raman lidar, and Raman DIAL. Of the numerous new developments in actual progress, one example, BELINDA, has been chosen that in a way marks the borderline between elastic backscatter and differential absorption lidar.

  10. The making of extraordinary psychological phenomena.

    PubMed

    Lamont, Peter

    2012-01-01

    This article considers the extraordinary phenomena that have been central to unorthodox areas of psychological knowledge. It shows how even the agreed facts relating to mesmerism, spiritualism, psychical research, and parapsychology have been framed as evidence both for and against the reality of the phenomena. It argues that these disputes can be seen as a means through which beliefs have been formulated and maintained in the face of potentially challenging evidence. It also shows how these disputes appealed to different forms of expertise, and that both sides appealed to belief in various ways as part of the ongoing dispute about both the facts and expertise. Finally, it shows how, when a formal Psychology of paranormal belief emerged in the twentieth century, it took two different forms, each reflecting one side of the ongoing dispute about the reality of the phenomena. PMID:25363382

  11. Atmospheric evolution

    NASA Astrophysics Data System (ADS)

    Bolle, H.-J.

    One of the most important boundary conditions imposed on planetary formation theories by planetary atmosphere gas abundances is that the volatiles present are not likely to have undergone a hot phase during early accretion, and must therefore have been added at a later stage if such a hot phase did occur. As a consequence, and in contrast with the survival of primordial or solar abundances in such outer planets as Jupiter, the inner planets have undergone major transformations: (1) on Venus and Mars, water must have been dissociated, resulting in the escape of hydrogen; (2) carbon was probably bound chemically in the Martian crust, while (3) it could not react with Venus crustal materials because of the high temperatures generated by the greenhouse effect; and (4) on the earth, due to intermediate temperatures, the most significant change has been the generation of life, with its attendant transformation of an originally reducing atmosphere into an oxidizing one.

  12. Atmospheric Dust

    NSDL National Science Digital Library

    2014-09-14

    Atmospheric dust storms are common in many of the world's semi-arid and arid regions and can impact local, regional, and even global weather, agriculture, public health, transportation, industry, and ocean health. This module takes a multifaceted approach to studying atmospheric dust storms. The first chapter examines the impacts of dust storms, the physical processes involved in their life cycle, their source regions, and their climatology. The second chapter explores satellite products (notably dust RGBs) and dust models used for dust detection and monitoring, and presents a process for forecasting dust storms. The third and final chapter of the module examines the major types of dust storms: those that are synoptically forced, such as pre- and post-frontal dust storms and those induced by large-scale trade winds; and those caused by mesoscale systems such as downslope winds, gap flow, convection, and inversion downburst storms.

  13. Fundamental investigation of duct/ESP phenomena

    SciTech Connect

    Brown, C.A. (Radian Corp., Austin, TX (United States)); Durham, M.D. (ADA Technologies, Inc., Englewood, CO (United States)); Sowa, W.A. (California Univ., Irvine, CA (United States). Combustion Lab.); Himes, R.M. (Fossil Energy Research Corp., Laguna Hills, CA (United States)); Mahaffey, W.A. (CHAM of North America, Inc., Huntsville, AL (United States))

    1991-10-21

    Radian Corporation was contracted to investigate duct injection and ESP phenomena in a 1.7 MW pilot plant constructed for this test program. This study was an attempt to resolve problems found in previous studies and answer remaining questions for the technology using an approach which concentrates on the fundamental mechanisms of the process. The goal of the study was to obtain a better understanding of the basic physical and chemical phenomena that control: (1) the desulfurization of flue gas by calcium-based reagent, and (2) the coupling of an existing ESP particulate collection device to the duct injection process. Process economics are being studied by others. (VC)

  14. Modeling of fundamental phenomena in welds

    SciTech Connect

    Zacharia, T.; Vitek, J.M. [Oak Ridge National Lab., TN (United States); Goldak, J.A. [Carleton Univ., Ottawa, Ontario (Canada); DebRoy, T.A. [Pennsylvania State Univ., University Park, PA (United States); Rappaz, M. [Ecole Polytechnique Federale de Lausanne (Switzerland); Bhadeshia, H.K.D.H. [Cambridge Univ. (United Kingdom)

    1993-12-31

    Recent advances in the mathematical modeling of fundamental phenomena in welds are summarized. State-of-the-art mathematical models, advances in computational techniques, emerging high-performance computers, and experimental validation techniques have provided significant insight into the fundamental factors that control the development of the weldment. The current status and scientific issues in the areas of heat and fluid flow in welds, heat source metal interaction, solidification microstructure, and phase transformations are assessed. Future research areas of major importance for understanding the fundamental phenomena in weld behavior are identified.

  15. Atmosphere Webquest

    NSDL National Science Digital Library

    Mr. Talley

    2011-09-27

    Use the websites and games provided to answer questions, complete diagrams, and learn more about our Earth's atmosphere TOPIC 1 - Weather vs. Climate - Let's start with a game. Open up Online Stopwatch and click on the stopwatch setting. - Use the stopwatch to time yourself as you play through all three levels of The Weather Game. - On your own piece of paper write down how long it took you to pass all ...

  16. Various superstable synchronous phenomena in switch-coupled relaxation oscillators

    Microsoft Academic Search

    Fumitaka Komatsu; Hiroyuki Torikai; Toshimichi Saito

    2001-01-01

    This paper considers synchronous phenomena from switch-coupled relaxation oscillators. This system exhibits a variety of interesting superstable synchronous phenomena. Using a hybrid return map, we can analyze the phenomena almost completely. Using a simple circuit, typical phenomena are verified in the laboratory

  17. Superstable Synchronous Phenomena of Switch-Coupled Relaxation Oscillators

    Microsoft Academic Search

    Toshimichi SAITO; Fumitaka KOMATSU; Hiroyuki TORIKAI

    2002-01-01

    SUMMARY As two simple relaxation oscillators are coupled by periodical and instantaneous switching, the system exhibits rich superstable synchronous phenomena. In order to analyze the phenomena, we derive a hybrid return map of real and binary variables;and give theoretical results for (1) superstability of the synchronous phenomena and (2) period of the synchronous phenomena as a function of the parameters.

  18. Effects on the Ionosphere Due to Phenomena Occurring Below it

    NASA Astrophysics Data System (ADS)

    Kazimirovsky, E.; Herraiz, M.; De La Morena, B. A.

    2003-03-01

    The terrestrial thermosphere and ionosphere form the most variable part of the Earth's atmosphere. Because our society depends on technological systems that can be affected by thermospheric and ionospheric phenomena, understanding, monitoring and ultimately forecasting the changes of the thermosphere-ionosphere system are of crucial importance to communications, navigation and the exploration of near-Earth space. The reason for the extreme variability of the thermosphere-ionosphere system is its rapid response to external forcing from various sources, i.e., the solar ionizing flux, energetic charged particles and electric fields imposed via the interaction between the solar wind, magnetosphere and ionosphere, as well as coupling from below (``meteorological influences'') by the upward propagating, broad spectrum, internal atmospheric waves (planetary waves, tides, gravity waves) generated in the stratosphere and troposphere. Thunderstorms, typhoons, hurricanes, tornadoes and even seismological events may also have observable consequences in the ionosphere. The release of trace gases due to human activity have the potential to cause changes in the lower and the upper atmosphere. A brief overview is presented concerning the discoveries and experimental results that have confirmed that the ionosphere is subject to meteorological control (especially for geomagnetic quiet conditions and for middle latitudes). D-region aeronomy, the winter anomaly of radiowave absorption, wave-like travelling ionospheric disturbances, the non-zonality and regional peculiarities of lower thermospheric winds, sporadic-E occurrence and structure, spread-F events, the variability of ionospheric electron density profiles and Total Electron Content, the variability of foF2, etc., should all be considered in connection with tropospheric and stratospheric processes. ``Ionospheric weather'', as a part of space weather, (i.e., hour-to-hour and day-to-day variability of the ionospheric parameters) awaits explanation and prediction within the framework of the climatological, seasonal, and solar-cycle variations.

  19. Research on atmospheric volcanic emissions - An overview

    NASA Technical Reports Server (NTRS)

    Friend, J. P.; Bandy, A. R.; Moyers, J. L.; Zoller, W. H.; Stoiber, R. E.; Torres, A. L.; Rose, W. I., Jr.; Mccormick, M. P.; Woods, D. C.

    1982-01-01

    Atmospheric abundances and the geochemical cycle of certain volatile compounds and elements may be largely influenced or entirely controlled by magmatic sources. However, better estimates of the magnitude and variability of volcanic emissions are required if the importance of this natural source of atmospheric constituents and the resulting effect on atmospheric chemistry are to be elucidated. The project 'Research on Atmospheric Volcanic Emissions' (RAVE) is concerned with the improvement of knowledge of both geological and chemical phenomena attending these emissions by means of comprehensive instrumentation on board a research aircraft making simultaneous measurements of plume constituents. A description is presented of the equipment and the procedures used in the RAVE field study of Mt. St. Helens' plume. An overview of the results is also provided.

  20. Evolution of Terrestrial Atmospheres

    NSDL National Science Digital Library

    O'Connell, Robert W.

    This lecture compares terrestrial atmospheres as well as discusses atmospheric processes, atmospheric equilibrium, and the atmospheric development of Mars, Venus, and Earth. It ends with a discussion of natural and unnatural climatic changes.

  1. University of Oxford: Atmospheric, Oceanic, and Planetary Physics

    NSDL National Science Digital Library

    The University of Oxford's Atmospheric, Oceanic, and Planetary Physics group "focuses on the study of physical processes in the atmospheres and oceans of the Earth and other planets, using experimental and theoretical techniques." Users can discover the group's innumerable projects and research tools in the areas involving the development of instruments and carrying out experiments mostly on satellites; analyses of data; and modeling and theoretical work related primarily to climate change, the middle atmosphere, planetary atmospheres, and to laboratory experiments on fluids. Individuals can find informational materials about its facilities and capabilities. The website answers a host of questions related to climate change, the ozone, and planetary phenomena.

  2. Quantum Theory of Electrical Transport Phenomena. II

    Microsoft Academic Search

    J. M. Luttinger; W. Kohn

    1958-01-01

    In a previous paper we have developed a theory of electrical transport phenomena for a simple quantum-mechanical model. That treatment was based on an expansion in powers of the strength of the scattering mechanism. In the present paper we consider the same model, but obtain the transport equation in powers of the density of scatterers without restricting ourselves to weak

  3. Possible new wave phenomena in the brain

    E-print Network

    Jerzy Szwed

    2009-08-10

    We propose to search for new wave phenomena in the brain by using interference effects in analogy to the well-known double slit (Young) experiment. This method is able to extend the range of oscillation frequencies to much higher values than currently accessible. It is argued that such experiments may test the hypothesis of the wave nature of information coding.

  4. Phenomenal data mining: from data to phenomena

    Microsoft Academic Search

    John McCarthy

    2000-01-01

    Phenomenal data mining finds relations between the data and the phenomena that give rise to data rather than just relations among the data.For example, suppose supermarket cash register data does not identify cash customers. Nevertheless, there really are customers, and these customers are characterized by sex, age, ethnicity, tastes, income distribution, and sensitivity to price changes. A data mining program

  5. MIXING PHENOMENA IN INDUSTRIAL FUME AFTERBURNER SYSTEMS

    EPA Science Inventory

    The report reviews the physical-mixing phenomena involved in the reactions that occur in afterburners or fume incinerators. It considers mixing in after-burners from three points of view. It first covers typical designs of afterburner components that are involved in the mixing ph...

  6. Passive Localization Methods based on Distributed Phenomena

    E-print Network

    Henderson, Thomas C.

    Passive Localization Methods based on Distributed Phenomena Felix Sawo, Thomas C. Henderson, Christopher Sikorski, and Uwe D. Hanebeck Abstract This paper is devoted to methods for localizing individual.e., rigorous exploitation of physical background knowledge) using local observations of a distributed

  7. Spin Circuit Representation for Spin Pumping Phenomena

    NASA Astrophysics Data System (ADS)

    Roy, Kuntal; Datta, Supriyo

    2015-03-01

    There has been enormous progress in the field of spintronics and nanomagnetics in recent years with the discovery of many new materials and phenomena and it remains a formidable challenge to integrate these phenomena into functional devices and evaluate their potential. To facilitate this process a modular approach has been proposed whereby different phenomena are represented by spin circuit components. Unlike ordinary circuit components, these spin circuit components are characterized by 4-component voltages and currents (one for charge and three for spin). In this talk we will (1) present a spin circuit representation for spin pumping phenomena, (2) combine it with a spin circuit representation for the spin Hall effect to show that it reproduces established results obtained earlier by other means, and finally (3) use it to propose a possible method for enhancing the spin pumping efficiency by an order of magnitude through the addition of a spin sink layer. This work was supported by FAME, one of six centers of STARnet, a Semiconductor Research Corporation program sponsored by MARCO and DARPA.

  8. Multiple time scale analysis of runaway phenomena

    Microsoft Academic Search

    Lucio Demeio

    1998-01-01

    The analysis of runaway phenomena with the use of the Boltzmann equation shows that the time evolution of the distribution function and of the other quantities of interest, for example the average velocity, occurs on two time scales: the short time scale of the collisional equilibrium and the long time scale of the runaway flux. Under suitable conditions on the

  9. Phasor analysis of some stereophonic phenomena

    Microsoft Academic Search

    B. Bauer

    1962-01-01

    An improved understanding of some stereophonic phenomena may be obtained by use of acoustical pressure phasors to portray sound pressure at the ears of the observer. With the help of phasors, it is possible to expand and modify certain conclusions of previous observers and to validate some previously unpublished observations: a stereophonic \\

  10. Gods, Heroes and Natural Phenomena Cosmologies

    Microsoft Academic Search

    Miguel Angel Alarcón

    People have always been worried about the natural phenomena that have influenced their lives and the origin of these natural changes. That is why they have always tried to explain the creation of the world probably as a way to control it, protect them from it, or simply to understand it. It is always relevant to humankind to try to

  11. Observations of Nonlinear Phenomena in Rotordynamics

    NASA Astrophysics Data System (ADS)

    Ehrich, Fredric F.

    Observations, analysis and understanding of nonlinear rotordynamic phenomena observed in aircraft gas turbine engines and other high-speed rotating machinery over the course of the author's career are described. Included are observations of sum-and-difference frequency response; effects of roller bearing clearance; relaxation oscillations; subharmonic response; chaotic response; and other generic nonlinear responses such as superharmonic and ultra-subharmonic response.

  12. Exploratorium Exhibit and Phenomena Cross Reference

    NSDL National Science Digital Library

    This alphabetical list of links explains a variety of scientific phenomena. Clicking on the name of a particular phenomenon will provide the user with a written definition or description and a list of links to exhibits (another part of the site) which illustrate it.

  13. Geophysical phenomena classification by artificial neural networks

    NASA Technical Reports Server (NTRS)

    Gough, M. P.; Bruckner, J. R.

    1995-01-01

    Space science information systems involve accessing vast data bases. There is a need for an automatic process by which properties of the whole data set can be assimilated and presented to the user. Where data are in the form of spectrograms, phenomena can be detected by pattern recognition techniques. Presented are the first results obtained by applying unsupervised Artificial Neural Networks (ANN's) to the classification of magnetospheric wave spectra. The networks used here were a simple unsupervised Hamming network run on a PC and a more sophisticated CALM network run on a Sparc workstation. The ANN's were compared in their geophysical data recognition performance. CALM networks offer such qualities as fast learning, superiority in generalizing, the ability to continuously adapt to changes in the pattern set, and the possibility to modularize the network to allow the inter-relation between phenomena and data sets. This work is the first step toward an information system interface being developed at Sussex, the Whole Information System Expert (WISE). Phenomena in the data are automatically identified and provided to the user in the form of a data occurrence morphology, the Whole Information System Data Occurrence Morphology (WISDOM), along with relationships to other parameters and phenomena.

  14. Detonation phenomena observed with a CCD camera

    Microsoft Academic Search

    Manfred Held

    1995-01-01

    With an appropriate test set up, the Hadland Photonics Ballistic Range Camera (SVR), designed primarily for exterior and terminal ballistics, can also be used very well for studying initiation events and analyzing a variety of detonation phenomena. This paper explains in detail the test set up of one interesting detonic experiment, observed with the Ballistic Range Camera, and the analysis

  15. Wave Phenomena in an Acoustic Resonant Chamber

    ERIC Educational Resources Information Center

    Smith, Mary E.; And Others

    1974-01-01

    Discusses the design and operation of a high Q acoustical resonant chamber which can be used to demonstrate wave phenomena such as three-dimensional normal modes, Q values, densities of states, changes in the speed of sound, Fourier decomposition, damped harmonic oscillations, sound-absorbing properties, and perturbation and scattering problems.…

  16. Emergent Cultural Phenomena and their Cognitive Foundations

    Microsoft Academic Search

    Christian Cordes

    2007-01-01

    To explain emergent cultural phenomena, this paper argues, it is inevitable to understand the evolution of complex human cognitive adaptations and their links to the population-level dynamics of cultural variation. On the one hand, the process of cultural transmission is influenced and constrained by humans’ evolved psychology; people tend to acquire some cultural variants rather than others. On the other

  17. Graphics for Lunar Phenomena 2014 Sept 26

    E-print Network

    Gaudi, B. Scott

    in Latitude Moon's rotation axis tilted 6.5° relative to its orbital plane See past North pole See past South Moon at Apogee a(1+e) = 405,000 km Moon's Orbit is Elliptical: e = 0.055 #12;Annular Eclipse #12;NewGraphics for Lunar Phenomena 2014 Sept 26 #12;New Moon Full Moon Waning Crescent Last Quarter

  18. Graphics for Lunar Phenomena 2013 Sept 18

    E-print Network

    Gaudi, B. Scott

    in Latitude Moon's rotation axis tilted 6.5° relative to its orbital plane See past North pole See past South Moon at Apogee a(1+e) = 405,000 km Moon's Orbit is Elliptical: e = 0.055 #12;Annular Eclipse #12;NewGraphics for Lunar Phenomena 2013 Sept 18 #12;New Moon Full Moon Waning Crescent Last Quarter

  19. Atmospheric angular momentum fluctuations during 1979–1988 simulated by global circulation models

    Microsoft Academic Search

    R. Hide; J. O. Dickey; S. L. Marcus; R. D. Rosen; D. A. Salstein

    1998-01-01

    This note summarizes the main findings of an investigation described in detail in a recently-published paper (Hide et al. 1997) and presented at a symposium on “Modelling of global change phenomena with observational geodetic and geophysical constraints” held during the 1997 Congress in Vienna of the European Geophysical Society.Changes in major global dynamical phenomena in the Earth's atmosphere are manifested

  20. Physics and chemistry of upper atmospheres of planets from infrared observations

    Microsoft Academic Search

    Theodor Kostiuk

    1994-01-01

    An important goal of the study of atmospheres of planets is to provide an understanding of the relationship and interaction among phenomena occurring at different altitude and pressure regions and the effects of external influences on these phenomena. To probe multiple pressure regimes in general requires measurements in different spectral regions and with a wide range of spectral resolutions. This

  1. Atmospheric correction: Computing atmospheric diffuse transmittance

    Microsoft Academic Search

    Jinji Ma; Shizhi Yang; Xianbing Wang; Yanli Qiao

    2006-01-01

    If we can accurately compute the leaving-water radiance and atmospheric diffuse transmittance, we will accurately retrieve the atmosphere optical properties over the case II water by MODIS image. According to the paper by Wang [Wang, Menghua, 1999. Atmospheric correction of ocean color sensors: computing atmospheric diffuse transmittance. Appl. Opt. 38, 451–455] to using the reciprocal equation derived by Yang and

  2. Rate constants for atmospheric trace organics scavenging SO 4 ? in the Fe-catalysed autoxidation of S(IV)

    Microsoft Academic Search

    J. Ziajka; W. Pasiuk-Bronikowska

    2005-01-01

    Numerous organic compounds are released into the atmosphere in globally large quantities. Chemical transformation of these compounds under the influence of other atmospheric components has not yet been fully recognised. One of the uncertainties is the importance of the mechanism and kinetics of atmospheric reactions involving organics for the quantitative description of such phenomena as the formation of aerosols and

  3. Optimizing Laboratory Experiments for Dynamic Astrophysical Phenomena

    SciTech Connect

    Ryutov, D. D.; Remington, B. A. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States)

    2006-04-07

    To make laboratory experiments an efficient tool for the studying the dynamical astrophysical phenomena, it is desirable to perform them in such a way as to satisfy the scaling invariance with respect to the astrophysical system under study. Several examples are presented of such scalings in the area of magnetohydrodynamic phenomena, where a number of scaled experiments have been performed. A difficult issue of the effect of fine-scale dissipative structures on the global scale dissipation-free flow is discussed. The second part of the paper is concerned with much less developed area of the scalings relevant to the interaction of an ultra-intense laser pulse with a pre-formed plasma. The use of the symmetry arguments in such experiments is also considered.

  4. Optimizing Laboratory Experiments for Dynamic Astrophysical Phenomena

    SciTech Connect

    Ryutov, D; Remington, B

    2005-09-13

    To make a laboratory experiment an efficient tool for the studying the dynamical astrophysical phenomena, it is desirable to perform them in such a way as to observe the scaling invariance with respect to the astrophysical system under study. Several examples are presented of such scalings in the area of magnetohydrodynamic phenomena, where a number of scaled experiments have been performed. A difficult issue of the effect of fine-scale dissipative structures on the global scale dissipation-free flow is discussed. The second part of the paper is concerned with much less developed area of the scalings relevant to the interaction of an ultra-intense laser pulse with a pre-formed plasma. The use of the symmetry arguments in such experiments is also considered.

  5. Phase-interface phenomena in multiphase flow

    SciTech Connect

    Hewitt, G.F. (Imperial College of Science, Technology and Medicine, London (GB)); Mayinger, F. (Technische Universitat Munchen, Munchen (DE)); Riznic, J.R. (Boris Kidric Inst. of Nuclear Sciences, Belgrade-Vinca (YU))

    1991-01-01

    Multiphase flow systems are prevalent in a wide range of power and chemical plants. The design of the components of such a plant is still based to a great extent on empirical correlations. One of the main barriers to a better understanding of the thermo- and fluid dynamic conditions in multiphase flows is the lack of knowledge and information on physical interactions between the phases at their interface. The seminar had the purpose of presenting the current state of knowledge on phase-interface phenomena and discussing the effects of interactions between the phases. Such interactions include the transfer of heat mass, and momentum. Depending on the flow pattern in the multiphase system and on the thermodynamic state of the phases, the interaction at the phase-interface can vary in form. The scientific program of the seminar, therefore, had to cover a wide range of physical phenomena.

  6. Combustion phenomena of highly metallized solid propellants

    NASA Astrophysics Data System (ADS)

    Laredo, D.; Gany, A.

    The surface phenomena associated with the combustion of highly metallized (e.g. 40-50% boron or magnesium) solid propellants are studied by means of high speed photography (4000 pictures per second), using a windowed high pressure strand burner. The motion pictures were analyzed frame by frame to yield agglomerate size distribution, propellant regression rate, and surface processes. Propellants containing boron additives in the range of 40% (with original sub-micron particles) exhibit irregular combustion with a sort of periodic phenomena, regarding the regression rate, metal agglomeration, ejection of unburnt propellant layers, and other surface processes. Boron particles tend to agglomerate with typical agglomerate size in the range of 30-150 ?m. Effect of pressure on the various processes is investigated.

  7. Breakdown phenomena in high power klystrons

    SciTech Connect

    Vlieks, A.E.; Allen, M.A.; Callin, R.S.; Fowkes, W.R.; Hoyt, E.W.; Lebacqz, J.V.; Lee, T.G.

    1988-03-01

    In the course of developing new high peak power klystrons at SLAC, high electric fields in several regions of these devices have become an important source of vacuum breakdown phenomena. In addition, a renewed interest in breakdown phenomena for nanosecond pulse, multi-megavolt per centimeter fields has been sparked by recent R and D work in the area of gigawatt RF sources. The most important regions of electrical breakdown are in the output cavity gap area, the RF ceramic windows, and the gun ceramic insulator. The details of the observed breakdown in these regions, experiments performed to understand the phenomena and solutions found to alleviate the problems will be discussed. Recently experiments have been performed on a new prototype R and D klystron. Peak electric fields across the output cavity gaps of this klystron exceed 2 MV/cm. The effect of peak field duration (i.e. pulse width) on the onset of breakdown have been measured. The pulse widths varied from tens of nanoseconds to microseconds. Results from these experiments will be presented. The failure of ceramic RF windows due to multipactor and puncturing was an important problem to overcome in order that our high power klystrons would have a useful life expectancy. Consequently many studies and tests were made to understand and alleviate window breakdown phenomena. Some of the results in this area, especially the effects of surface coatings, window materials and processing techniques and their effects on breakdown will be discussed. Another important source of klystron failure in the recent past at SLAC has been the puncturing of the high voltage ceramic insulator in the gun region. A way of alleviating this problem has been found although the actual cause of the puncturing is not yet clear. The ''practical'' solution to this breakdown process will be described and a possible mechanism for the puncturing will be presented. 9 refs., 5 figs., 3 tabs.

  8. Two new phenomena of holographic imaging

    NASA Astrophysics Data System (ADS)

    Cao, Junqing; Shao, Yinmei; Sun, Yiping; Li, Xiangning; Ding, Ye

    1996-09-01

    Two phenomena which are different form traditional observation results in holographic imaging are reported in this paper. They are double virtual images and so-called virtual pseudomorphic image. It is shown that here exists an appropriate condition for Fresnel hologram upon which two virtual images can be reconstructed. And it is also shown that the virtual pseudomorphic image could not be physical, but only psychological.

  9. Natural phenomena hazards site characterization criteria

    SciTech Connect

    Not Available

    1994-03-01

    The criteria and recommendations in this standard shall apply to site characterization for the purpose of mitigating Natural Phenomena Hazards (wind, floods, landslide, earthquake, volcano, etc.) in all DOE facilities covered by DOE Order 5480.28. Criteria for site characterization not related to NPH are not included unless necessary for clarification. General and detailed site characterization requirements are provided in areas of meteorology, hydrology, geology, seismology, and geotechnical studies.

  10. Nonlinear Phenomena in Canonical Stochastic Quantization

    E-print Network

    Helmuth Huffel

    2007-10-16

    Stochastic quantization provides a connection between quantum field theory and statistical mechanics, with applications especially in gauge field theories. Euclidean quantum field theory is viewed as the equilibrium limit of a statistical system coupled to a thermal reservoir. Nonlinear phenomena in stochastic quantization arise when employing nonlinear Brownian motion as an underlying stochastic process. We discuss a novel formulation of the Higgs mechanism in QED.

  11. Rectification Phenomena Across an Asymmetric Nanofluidic Channel

    NASA Astrophysics Data System (ADS)

    Chang, Hsueh-Chia

    2011-11-01

    We review our recent experimental and theoretical studies of nanofluidic diodes. A continuum theory is developed to show that the literature and our rectification data can be generically classified into two regimes: a low-voltage regime dominated by intra- channel ionic strength (Donnan potential) gradient and a high-voltage regime dominated by external ion depletion. The two regimes drive different anomalous phenomena, like molecular dissociation and microvortex instability, with distinct distinguished limits of dimensionless parameters. Applications to biosensing are discussed.

  12. Atmosphere Analyzer

    NASA Technical Reports Server (NTRS)

    1982-01-01

    California Measurements, Inc.'s model PC-2 Aerosol Particle Analyzer is produced in both airborne and ground-use versions. Originating from NASA technology, it is a quick and accurate method of detecting minute amounts of mass loadings on a quartz crystal -- offers utility as highly sensitive detector of fine particles suspended in air. When combined with suitable air delivery system, it provides immediate information on the size distribution and mass concentrations of aerosols. William Chiang, obtained a NASA license for multiple crystal oscillator technology, and initially developed a particle analyzer for NASA use with Langley Research Center assistance. Later his company produced the modified PC-2 for commercial applications Brunswick Corporation uses the device for atmospheric research and in studies of smoke particles in Fires. PC-2 is used by pharmaceutical and chemical companies in research on inhalation toxicology and environmental health. Also useful in testing various filters for safety masks and nuclear installations.

  13. Further investigations of oblique hypervelocity impact phenomena

    NASA Technical Reports Server (NTRS)

    Schonberg, William P.

    1988-01-01

    The results of a continuing investigation of the phenomena associated with the oblique hypervelocity impact of spherical projectiles onto multi-sheet aluminum structures are described. A series of equations that quantitatively describes these phenomena is obtained through a regression of experimental data. These equations characterize observed ricoshet and penetration damage phenomena in a multi-sheet structure as functions of the geometric parameters of the structure and the diameter, obliquity, and velocity of the impacting projectile. Crater damage observed on the ricochet witness plates is used to determine the sizes and speeds of the ricochet debris particles that caused the damage. It is shown that, in general, the most damaging ricochet debris particle is approximately 0.25 cm (0.10 in) in diameter and travels at the speed of approximately 2.1 km/sec (6,890 ft/sec). The equations necessary for the design of shielding panels that will protect external systems from such ricochet debris damage are also developed. The dimensions of these shielding panels are shown to be strongly dependent on their inclination and on their circumferential distribution around the spacecraft. It is concluded that obliquity effects of high-speed impacts must be considered in the design of any structure exposed to the meteoroid and space debris environment.

  14. Physical mechanism of membrane osmotic phenomena

    SciTech Connect

    Guell, D.C. [Los Alamos National Lab., NM (United States)] [Los Alamos National Lab., NM (United States); Brenner, H. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Chemical Engineering] [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Chemical Engineering

    1996-09-01

    The microscale, physicomechanical cause of osmosis and osmotic pressure in systems involving permeable and semipermeable membranes is not well understood, and no fully satisfactory mechanism has been offered to explain these phenomena. A general theory, albeit limited to dilute systems of inert, noninteracting solute particles, is presented which demonstrates that short-range forces exerted by the membrane on the dispersed solute particles constitute the origin of osmotic phenomena. At equilibrium, the greater total force exerted by the membrane on those solute particles present in the reservoir containing the more concentrated of the two solutions bathing the membrane is balanced by a macroscopically observable pressure difference between the two reservoirs. The latter constitutes the so-called osmotic pressure difference. Under nonequilibrium conditions, the membrane-solute force is transmitted to the solvent, thus driving the convective flow of solvent observed macroscopically as osmosis. While elements of these ideas have been proposed previously in various forms, the general demonstration offered here of the physicomechanical source of osmotic phenomena is novel. Beyond the purely academic interest that exists in establishing a mechanical understanding of osmotic pressure, the analysis lays the foundation underlying a quantitative theory of osmosis in dilute, nonequilibrium systems outlined in a companion paper.

  15. Stability and restoration phenomena in competitive systems

    NASA Astrophysics Data System (ADS)

    Uechi, Lisa; Akutsu, Tatsuya

    2013-10-01

    A conservation law along with stability, recovering phenomena, and characteristic patterns of a nonlinear dynamical system have been studied and applied to physical, biological, and ecological systems. In our previous study, we proposed a system of symmetric 2n-dimensional conserved nonlinear differential equations. In this paper, competitive systems described by a 2-dimensional nonlinear dynamical (ND) model with external perturbations are applied to population cycles and recovering phenomena of systems from microbes to mammals. The famous 10-year cycle of population density of Canadian lynx and snowshoe hare is numerically analyzed. We find that a nonlinear dynamical system with a conservation law is stable and generates a characteristic rhythm (cycle) of population density, which we call the standard rhythm of a nonlinear dynamical system. The stability and restoration phenomena are strongly related to a conservation law and the balance of a system. The standard rhythm of population density is a manifestation of the survival of the fittest to the balance of a nonlinear dynamical system.

  16. Space Weather Phenomena at the Galilean Satellites

    NASA Astrophysics Data System (ADS)

    Cessateur, Gaël; Barthelemy, Mathieu

    2015-04-01

    In the framework of the JUICE mission, characterization of Galilean satellites atmospheres is a priority. Although Ganymede and Europa possess a faint atmosphere, their exosphere show emissions features due to both solar UV flux as well as precipitating particles. Using the atmospheric model proposed by Marconi (2006,2007), we have developed a model of exospheric emissions by only considering primary collisions. Two regions will be considered for Ganymede, a polar one mainly dominated by oxygen, and an equatorial one with the predominance of water. Model of Europa's atmosphere presents an uniform one dominated by oxygen. Since Ganymede has its own magnetic field, the polar regions are mainly affected by particle precipitations while in case of Europe, the whole atmosphere has to be considered. Comparison with direct observations such as local measurements from Galileo (electronic density), or remote observations with the Hubble Space Telescope in the UV (oxygen lines at 130.5 and 135.5 nm), shows a good agreement which ensures us to provide reasonable constraints for the JUICE mission.

  17. On the Physics of the Critical Ionization Velocity Phenomena

    Microsoft Academic Search

    K. Papadopoulos

    1985-01-01

    The interplay of collisional and collisionless phenomena in the interaction of a magnetoplasma streaming through neutral gas produces some of the most fascinating plasma physics phenomena. A key notion controlling such interactions is the existence of a \\

  18. Terrestrial Planet Atmospheres. The Moon's Sodium Atmosphere

    E-print Network

    Walter, Frederick M.

    ? ­ Smaller planet mass? ­ Lightweight gases? #12;Venus and the Runaway GreenhouseTerrestrial Planet Atmospheres. II. #12;The Moon's Sodium Atmosphere #12;Mercury for a Planet · Equator heated more than poles · Hadley cell transport heat poleward

  19. Spherical formations in the atmosphere as a physical phenomenon

    Microsoft Academic Search

    A. I. Mesenyashin

    1995-01-01

    This paper presents an attempt to elucidate the physical nature of the stable luminous spherical formations that are sometimes observed in the atmosphere. It is suggested that there may be a connection between some of these natural formations and Unidentified Flying Objects. Properties common to spherical formations and ball lightnings have been found. A mathematical model describing such natural phenomena

  20. Modeling the Transport Phenomena in the Solution Precursor Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Shan, Yanguang

    2008-10-01

    Solution precursor plasma spraying has been used to produce finely structured ceramic coatings with nano- and sub-micrometric features. This process involves the injection of a solution spray of ceramic salts into a DC plasma jet under atmospheric condition. During the process, the solvent vaporizes as the droplet travel downstream. Solid particles are finally formed due to the precipitation of the solute, and the particle are heated up and accelerated to the substrate to generate the coating. This work describes a 3D model to simulate the transport phenomena and the trajectory and heating of the solution spray in the process. The jet-spray two-way interactions are considered. A simplified model is employed to simulate the evolution process and the formation of the solid particle from the solution droplet in the plasma jet. O'Rourke's droplet collision model is used to take into account of the influence of droplet collision. The influence of droplet breakup is also considered by implementing TAB droplet breakup models into the plasma jet model. The temperature and velocity fields of the jet are obtained and validated. The particle size, velocity, temperature and position distribution on the substrate are predicted.

  1. Establishment of the New Ecuadorian Solar Physics Phenomena Division

    NASA Astrophysics Data System (ADS)

    Lopez, E. D.

    2014-02-01

    Crucial physical phenomena occur in the equatorial atmosphere and ionosphere, which are currently understudied and poorly understood. Thus, scientific campaigns for monitoring the equatorial region are required in order to provide the necessary data for the physical models. Ecuador is located in strategic geographical position where these studies can be performed, providing quality data for the scientific community working in understanding the nature of these physical systems. The Quito Astronomical Observatory of National Polytechnic School is moving in this direction by promoting research in space sciences for the study of the equatorial zone. With the participation and the valuable collaboration of international initiatives such us AWESOME, MAGDAS, SAVNET and CALLISTO, the Quito Observatory is establishing a new space physics division on the basis of the International Space Weather Initiative. In this contribution, the above initiative is presented by inviting leaders of other scientific projects to deploy its instruments and to work with us providing the necessary support to the creation of this new strategic research center

  2. Aircraft Performance: Atmospheric Pressure

    E-print Network

    Aircraft Performance: Atmospheric Pressure FAA Handbook of Aeronautical Knowledge Chap 10 #12 ­ 21% Oxygen ­ 1% other gases (argon, helium, etc) · Most oxygen Atmospheric Pressure;High Density Altitude (worse performance) · High elevations · Low atmospheric pressures · High

  3. Studies of Novel Quantum Phenomena in Ruthenates

    SciTech Connect

    Mao, Zhiqiang

    2011-04-08

    Strongly correlated oxides have been the subject of intense study in contemporary condensed matter physics, and perovskite ruthenates (Sr,Ca)n+1RunO3n+1 have become a new focus in this field. One of important characteristics of ruthenates is that both lattice and orbital degrees of freedom are active and are strongly coupled to charge and spin degrees of freedom. Such a complex interplay of multiple degrees of freedom causes the properties of ruthenates to exhibit a gigantic response to external stimuli under certain circumstances. Magnetic field, pressure, and chemical composition all have been demonstrated to be effective in inducing electronic/magnetic phase transitions in ruthenates. Therefore, ruthenates are ideal candidates for searching for novel quantum phenomena through controlling external parameters. The objective of this project is to search for novel quantum phenomena in ruthenate materials using high-quality single crystals grown by the floating-zone technique, and investigate the underlying physics. The following summarizes our accomplishments. We have focused on trilayered Sr4Ru3O10 and bilayered (Ca1-xSrx)3Ru2O7. We have succeeded in growing high-quality single crystals of these materials using the floating-zone technique and performed systematic studies on their electronic and magnetic properties through a variety of measurements, including resistivity, Hall coefficient, angle-resolved magnetoresistivity, Hall probe microscopy, and specific heat. We have also studied microscopic magnetic properties for some of these materials using neutron scattering in collaboration with Los Alamos National Laboratory. We have observed a number of unusual exotic quantum phenomena through these studies, such as an orbital selective metamagnetic transition, bulk spin valve effect, and a heavy-mass nearly ferromagnetic state with a surprisingly large Wilson ratio. Our work has also revealed underlying physics of these exotic phenomena. Exotic phenomena of correlated electron has been among central topics of contempary condensed matter physics. Ultrfast phase transitions accompanied by switching of conductivity or magnetization in stronly correlated materials are believed to be promising in developing next generation of transistors. Our work on layered ruthenates has remarkably advanced our understanding of how the exotic phenomena of correlated electrons is governed by the complex interplay between charge, spin, lattice and orbital degrees of freedom. In addition to studies on ruthenates, we have also expanded our research to the emerging field of Fe-based superconductors, focusing on the iron chalcogenide Fe1+y(Te1-xSex) superconductor system. We first studied the superconductivity of this alloy system following the discovery of superconductivity in FeSe using polycrystalline samples. Later, we successfuly grew high-quality single crystals of these materials. Using these single crystals, we have determined the magnetic structure of the parent compound Fe1+yTe, observed spin resonance of superconducting state in optimally doped samples, and established a phase diagram. Our work has produced an important impact in this burgeoning field. The PI presented an invited talk on this topic at APS March meeting in 2010. We have published 19 papers in these two areas (one in Nature materials, five in Physical Review Letters, and nine in Physical Review B) and submitted two (see the list of publications attached below).

  4. High-resolution atmospheric observations by the Mars Odyssey Thermal Emission Imaging System

    Microsoft Academic Search

    Ai Inada; Mark I. Richardson; Timothy H. McConnochie; Melissa J. Strausberg; Huiqun Wang; James F. Bell

    2007-01-01

    High-resolution observations of atmospheric phenomena by the Mars Odyssey Thermal Emission Imaging System (THEMIS) during its first mapping year are presented. An atmospheric campaign was implemented on the basis of previous spacecraft imaging. This campaign, however, proved of limited success. This appears to be due to the late local time of the Odyssey orbit (the locations of activity at 4–6

  5. Atmospheric angular momentum fluctuations during 1979-1988 simulated by global circulation models

    Microsoft Academic Search

    R. Hide; J. O. Dickey; S. L. Marcus; R. D. Rosen; D. A. Salstein

    1997-01-01

    Changes in major global dynamical phenomena in the Earth's atmosphere are manifested in the time series of atmospheric angular momentum (AAM), as determined directly from meteorological observations and indirectly from geodetic observations of small fluctuations in the rotation of the solid Earth which are proportional to length of day. AAM fluctuations are intimately linked with energetic processes throughout the whole

  6. Atmospheric angular momentum fluctuations during 1979–1988 simulated by global circulation models

    Microsoft Academic Search

    R. Hide; J. O. Dickey; S. L. Marcus; R. D. Rosen; D. A. Salstein

    1997-01-01

    Changes in major global dynamical phenomena in the Earth's atmosphere are mani- fested in the time series of atmospheric angular momentum (AAM), as determined directly from meteorological observations and indirectly from geodetic observations of small fluctuations in the rotation of the solid Earth which are proportional to length of day. AAM fluctuations are inti- mately linked with energetic processes throughout

  7. WIND TUNNEL MODELING OF THE ATMOSPHERIC BOUNDARY LAYER FLOW, TAKING INTO ACCOUNT EARTH'S ROTATION EFFECTS

    Microsoft Academic Search

    Mircea DEGERATU

    The way in which gaseous pollutants are released in the atmosphere, their transportation and dispersion in the moving air are in close relation with the mete- orological data of the site. The great majority of the dispersion phenomena take place in the atmospheric boundary layer which is some hundred meters thick. The great number of factors that appear in the

  8. On Four Independent Phenomena Sharing a Common Cause

    Microsoft Academic Search

    Roger Ellman

    2000-01-01

    Four independent unrelated phenomena, none of which has an established explanation, have now been extensively observed and a large amount of data substantiating the phenomena have been developed. The phenomena are as follows. - In 1933 F. Zwicky reported that the rotational balance of gravitational central attraction and rotational centripetal force in galaxies appeared to be out of balance, that

  9. ARCHER - a prototype expert system for identifying some meteorological phenomena

    SciTech Connect

    Moninger, W.R.

    1988-02-01

    ARCHER is a computer expert system that attempts to identify meteorological phenomena from their signatures on Doppler radar. Probabilities that phenomena under study could be any one of a number of possible meteorological archetypes (i.e., stereotyped phenomena such as convective cells of gust fronts) are determined by comparing current evidence with stored meteorological knowledge. 8 references.

  10. Diffractive Phenomena in High Energy Processes

    NASA Astrophysics Data System (ADS)

    Frankfurt, L.; Strikman, M.

    2013-06-01

    We review the evolution of the studies on diffractive processes in the strong interaction over the last 60 years. First, we briefly outline the early developments of the theory based on analyticity and unitarity of the S-matrix, including the derivation and exploration of Regge trajectories and related moving cuts. Special attention is paid to the concept of the Pomeron trajectory introduced for the description of total, elastic and diffractive cross-sections at high energies and to the emergence of the dynamics of multi-Pomeron interactions. The role of large longitudinal distances and color coherent phenomena for the understanding of inelastic diffraction in hadron-hadron scattering and deep inelastic scattering is emphasized. The connection of these phenomena to the cancellation of the contribution of the Glauber approximation in hadron-nucleus collisions and to the understanding of the Gribov-Glauber approximation is explained. The presence of different scales in perturbative QCD due to masses of heavy quarks has led to the emergence of numerous new phenomena including non-universality of the slopes of Regge trajectories made of light and heavy quarks and non-universal energy dependence of elastic cross-sections. The application of perturbative QCD techniques allowed us to calculate from first principles the interaction of small-transverse-size color singlets with hadrons leading to the development of the quantitative theory of hard exclusive reactions and to the successful prediction of many regularities in hard large mass diffraction. It also led to the prediction of the phenomenon of complete transparency of nuclear matter in QCD in special processes. The conflict of perturbative QCD with probability conservation for high energy processes of virtual photon-nucleon scattering is explained. Some properties of the new QCD regime are outlined...

  11. Observations of cometary plasma wave phenomena

    NASA Technical Reports Server (NTRS)

    Scarf, F. L.; Coroniti, F. V.; Kennel, C. F.; Gurnett, D. A.; Ip, W.-H.; Smith, E. J.

    1986-01-01

    The ICE plasma wave investigation utilized very long electric antennas (100 m tip-to-tip) and a very high sensitivity magnetic search coil to obtain significant local information on plasma physics phenomena occurring in the distant pickup regions of Comet Giacobini-Zinner and Comet Halley; and information on the processes that developed in the coma and tail of Giacobini-Zinner. The ICE plasma wave measurements associated with both comet encounters are summarized, and high sensitivity ICE observations are related to corresponding measurements from the other Halley spacecraft.

  12. Electronic phenomena in adsorption and catalysis

    SciTech Connect

    Kiselev, V.F.; Krylov, O.V.

    1987-01-01

    This book is the second of a three-volume treatment prepared by a physicist and a chemist, who took a common standpoint in considering the close relationship between the electronic processes taking place on the semiconductor-dielectric interface on the one hand, and the adsorptive and catalytic phenomena on the other. This volume brings together, and generalizes, a vast bulk of knowledge on the nature of surface and interface states, on the mechanism of surface electronic processes in semiconductors, as well as considers ways of controlling these processes. In addition, the authors discuss plausible mechanisms of elementary acts in surface charging during adsorption and catalysis.

  13. Detonation phenomena observed with a CCD camera

    NASA Astrophysics Data System (ADS)

    Held, Manfred

    1995-05-01

    With an appropriate test set up, the Hadland Photonics Ballistic Range Camera (SVR), designed primarily for exterior and terminal ballistics, can also be used very well for studying initiation events and analyzing a variety of detonation phenomena. This paper explains in detail the test set up of one interesting detonic experiment, observed with the Ballistic Range Camera, and the analysis of the results. The ability of the camera to superimpose up to 16 exposures on a single image allowed particularly detailed examination of the detonation propagation, the detonation velocities, the corner turning distance and the nonreacting radial zones.

  14. Animal network phenomena: insights from triadic games

    NASA Astrophysics Data System (ADS)

    Mesterton-Gibbons, Mike; Sherratt, Tom N.

    Games of animal conflict in networks rely heavily on computer simulation because analysis is difficult, the degree of difficulty increasing sharply with the size of the network. For this reason, virtually the entire analytical literature on evolutionary game theory has assumed either dyadic interaction or a high degree of symmetry, or both. Yet we cannot rely exclusively on computer simulation in the study of any complex system. So the study of triadic interactions has an important role to play, because triads are both the simplest groups in which asymmetric network phenomena can be studied and the groups beyond dyads in which analysis of population games is most likely to be tractable, especially when allowing for intrinsic variation. Here we demonstrate how such analyses can illuminate a variety of behavioral phenomena within networks, including coalition formation, eavesdropping (the strategic observation of contests between neighbors) and victory displays (which are performed by the winners of contests but not by the losers). In particular, we show that eavesdropping acts to lower aggression thresholds compared to games without it, and that victory displays to bystanders will be most intense when there is little difference in payoff between dominating an opponent and not subordinating.

  15. WHC natural phenomena hazards mitigation implementation plan

    SciTech Connect

    Conrads, T.J.

    1996-09-11

    Natural phenomena hazards (NPH) are unexpected acts of nature which pose a threat or danger to workers, the public or to the environment. Earthquakes, extreme winds (hurricane and tornado),snow, flooding, volcanic ashfall, and lightning strike are examples of NPH at Hanford. It is the policy of U.S. Department of Energy (DOE) to design, construct and operate DOE facilitiesso that workers, the public and the environment are protected from NPH and other hazards. During 1993 DOE, Richland Operations Office (RL) transmitted DOE Order 5480.28, ``Natural Phenomena Hazards Mitigation,`` to Westinghouse Hanford COmpany (WHC) for compliance. The Order includes rigorous new NPH criteria for the design of new DOE facilities as well as for the evaluation and upgrade of existing DOE facilities. In 1995 DOE issued Order 420.1, ``Facility Safety`` which contains the same NPH requirements and invokes the same applicable standards as Order 5480.28. It will supersede Order 5480.28 when an in-force date for Order 420.1 is established through contract revision. Activities will be planned and accomplished in four phases: Mobilization; Prioritization; Evaluation; and Upgrade. The basis for the graded approach is the designation of facilities/structures into one of five performance categories based upon safety function, mission and cost. This Implementation Plan develops the program for the Prioritization Phase, as well as an overall strategy for the implemention of DOE Order 5480.2B.

  16. EUV Dimmings: Formation Mechanisms and Associated Phenomena

    NASA Astrophysics Data System (ADS)

    Thompson, B. J.; Mays, M. L.; West, M. J.

    2012-12-01

    Large-scale coronal EUV dimmings, developing on timescales of minutes to hours in association with a flare or filament eruption, are known to exhibit a high correlation with coronal mass ejections. While most observations indicate that the decrease in emission in a dimming is due, at least in part, to a density decrease, a complete understanding requires us to examine at least four mechanisms that have been observed to cause darkened regions in the corona: 1) mass loss, 2) cooling, 3) heating, and 4) absorption/obscuration. Recent advances in automatic detection, observations with improved cadence and resolution, multi-viewpoint imaging, and spectroscopic studies have continued to shed light on dimming formation, evolution, and recovery. However, there are still some outstanding questions, including 1) Why do some CMEs show dimming and some do not? 2) What determines the location of a dimming? 3) What determines the temporal evolution of a dimming? 4) How does the post-eruption dimming connect to the ICME? 5) What is the relationship between dimmings and other CME-associated phenomena? The talk will emphasize the different formation mechanisms of dimmings and their relationship to CMEs and CME-associated phenomena.

  17. Emergent Magnetic Phenomena at Manganite Interfaces

    NASA Astrophysics Data System (ADS)

    Suzuki, Yuri

    2015-03-01

    Emergent phenomena at transition metal oxide interfaces have been the focus of recent intense study since the discovery of metallicity at the interface of LaAlO3 and SrTiO3 a decade ago. Emergent magnetic phenomena at transition metal oxide interfaces had been studied even earlier. However there have been surprisingly few systems demonstrating interfacial ferromagnetism especially combined with metallicity. Recently, we have developed a general picture describing the origin of interfacial ferromagnetism in CaMnO3 based systems. Density functional theory attributed the interfacial ferromagnetism to a double exchange interaction among interfacial Mn ions (just in the first single unit cell of CaMnO3) mediated by conduction electrons from the neighboring itinerant layer. We have demonstrated interfacial ferromagnetism in superlattices composed of the antiferromagnetic insulator CaMnO3 and an itinerant metal (CaRuO3 or LaNiO3). Through polarized neutron spectrometry, x-ray magnetic circular dichroism and bulk magmetometry, we have shown that the ferromagnetism originates from Mn ions in a single unit cell of the CaMnO3 at the interfaces as theoretically predicted. The modulation of interfacial ferromagnetic moment as a function of constituent layer thicknesses as well as long-range antiferromagnetic correlations in the CaMnO3, observed by neutron diffraction, are indicative of the competing magnetic interactions at play.

  18. Induction Phenomena in Laser-Sustained Scramjets

    SciTech Connect

    Ohkawa, Yoko; Tamada, Kazunobu; Horisawa, Hideyuki [Department of Aeronautics and Astronautics, Tokai University, 1117 Kitakaname, Hiratsuka, Kanagawa, 259-1292 (Japan); Kimura, Itsuro [University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8856 (Japan)

    2005-04-27

    A preliminary study on induction phenomena in a laser-sustained scramjet was conducted. The induction processes include absorption process of a laser pulse by a reactive mixture, plasma formation, diffusion of active species, shock formation, thermalization process of ambient mixture, induction of local turbulence, etc. For observation of the initial phenomena, an experimental study on effects of a focused laser pulse (Nd:YAG, 335mJ/pulse, pulse width 5nsec) into a hydrogen-air mixture was conducted. Temporal evolutions of typical line spectrum of a laser-induced plasma of the mixture were measured with the photodiode or the photo-multiplier-tube through specific band-pass filters for each spectrum for OH, O+, N+, H, and O. It was shown that the emission from O abruptly increased at 2 nsec, peaked at about 5 nsec, followed by an abrupt drop at 6 nsec. The emission from H atoms secondly increased. Other emissions of N+, O+, and OH peaked at about 17 nsec and continued for about 1 msec.

  19. Cavitation phenomena in extracorporeal microexplosion lithotripsy

    NASA Astrophysics Data System (ADS)

    Tomita, Y.; Obara, T.; Takayama, K.; Kuwahara, M.

    1994-09-01

    An experimental investigation was made of cavitation phenomena induced by underwater shock wave focusing applied to the extracorporeal microexplosion lithotripsy (microexplosion ESWL). Firstly an underwater microexplosion generated by detonation of a 10 mg silver azide pellet was studied and secondly underwater shock focusing and its induced cavitation phenomena were investgated. Underwater shock wave was focused by using a semi-ellipsoidal reflector in which a shock wave generated at the first focal point of the reflector was reflected and focused at the second focal point. It is found that an explosion product gas bubble did not produce any distinct rebound shocks. Meantime cavitation appeared after shock focusing at the second focal point where expansion waves originated at the exit of the reflector were simultaneously collected. A shock/bubble interaction is found to contribute not only to urinary tract stone disintegration but also tissue damage. The cavitation effect associated with the microexplosion ESWL was weaker in comparison with a spark discharge ESWL. The microexplosion ESWL is an effective method which can minimize the number of shock exposures hence decreasing tissue damage by conducting precise positioning of urinary tract stones.

  20. PREFACE: Transport phenomena in proton conducting media Transport phenomena in proton conducting media

    Microsoft Academic Search

    Michael Eikerling

    2011-01-01

    Proton transport phenomena are of paramount importance for acid-base chemistry, energy transduction in biological organisms, corrosion processes, and energy conversion in electrochemical systems such as polymer electrolyte fuel cells. The relevance for such a plethora of materials and systems, and the ever-lasting fascination with the highly concerted nature of underlying processes drive research across disciplines in chemistry, biology, physics and

  1. Present state of knowledge of the upper atmosphere: An assessment report

    NASA Technical Reports Server (NTRS)

    1984-01-01

    A program of research, technology, and monitoring of the phenomena of the upper atmosphere, to provide for an understanding of and to maintain the chemical and physical integrity of the Earth's upper atmosphere was developed. NASA implemented a long-range upper atmospheric science program aimed at developing an organized, solid body of knowledge of upper atmospheric processes while providing, in the near term, assessments of potential effects of human activities on the atmosphere. The effects of chlorofluorocarbon (CFC) releases on stratospheric ozone were reported. Issues relating the current understanding of ozone predictions and trends and highlights recent and future anticipated developments that will improve our understanding of the system are summarized.

  2. Light emission phenomena in superconducting niobium cavities

    SciTech Connect

    J.R. Delayen; J. Mammosser

    1999-03-01

    During the investigation of field emission limitations of superconducting niobium cavities, a CCD camera was inserted at the end of the beam pipe on a single-cell 1500 MHz cavity. When operating the cavity in field emission, glowing filaments of light were observed trapped by RF fields in closed-orbit trajectories. These filaments were traveling at frequencies much lower than the oscillating RF fields and formed various patterns of light for up to several seconds. This experiment was then repeated on a production CEBAF five-cell cavity with similar results. Events from both experiments were captured on video tape and are presented in this paper along with a discussion of the possible origin of these types of light patterns and the plans to further investigate the phenomena.

  3. Analysis of oblique hypervelocity impact phenomena

    NASA Technical Reports Server (NTRS)

    Schonberg, William P.; Taylor, Roy A.

    1988-01-01

    This paper describes the results of an experimental investigation of phenomena associated with the oblique hypervelocity impact of spherical projectiles on multisheet aluminum structures. A model that can be employed in the design of meteoroid and space debris protection systems for space structures is developed. The model consists of equations that relate crater and perforation damage of a multisheet structure to parameters such as projectile size, impact velocity, and trajectory obliquity. The equations are obtained through a regression analysis of oblique hypervelocity impact test data. This data shows that the response of a multisheet structure to oblique impact is significantly different from its response to normal hypervelocity impact. It was found that obliquely incident projectiles produce ricochet debris that can severely damage panels or instrumentation located on the exterior of a space structure. Obliquity effects of high-speed impact must, therefore, be considered in the design of any structure exposed to a meteoroid or space debris environement.

  4. Transient Phenomena: Opportunities for New Discoveries

    NASA Technical Reports Server (NTRS)

    Lazio, T. Joseph W.

    2010-01-01

    Known classes of radio wavelength transients range from the nearby (stellar flares and radio pulsars) to the distant Universe (gamma-ray burst afterglows). Hypothesized classes of radio transients include analogs of known objects, such as extrasolar planets emitting Jovian-like radio bursts and giant-pulse emitting pulsars in other galaxies, to the exotic, such as prompt emission from gamma-ray bursts, evaporating black holes and transmitters from other civilizations. Time domain astronomy has been recognized internationally as a means of addressing key scientific questions in astronomy and physics, and pathfinders and Precursors to the Square Kilometre Array (SKA) are beginning to offer a combination of wider fields of view and more wavelength agility than has been possible in the past. These improvements will continue when the SKA itself becomes operational. I illustrate the range of transient phenomena and discuss how the detection and study of radio transients will improve immensely.

  5. Topological Spintronics: Materials, Phenomena and Devices

    NASA Astrophysics Data System (ADS)

    Samarth, Nitin

    2015-03-01

    The two-dimensional surface states of three-dimensional topological insulators such as Bi2Se3and(Bi,Sb)2Te3 possess a spin texture that can potentially be exploited for spintronics applications. We provide a perspective on the emergence of ``topological spintronics,'' demonstrating how this spin texture can be engineered using either quantum tunneling between surfaces or by breaking time-reversal symmetry. We then discuss recent experiments that show striking spintronic phenomena useful for proof-of-concept devices, including a spin-orbit torque of record efficiency at room temperature and an electrically-gated ``giant anisotropic magnetoresistance'' at low temperature. This work was carried out in collaboration with A. Richardella, S.-Y. Xu, M. Neupane, A. Mellnik, A. Kandala, J. S. Lee, D. M. Zhang, M. Z. Hasan and D. C. Ralph. We acknowledge funding from the DARPA Meso program, ONR and C-SPIN (under sponsorship of MARCO and DARPA).

  6. Threshold Phenomena in a Throbbing Complex Plasma

    NASA Astrophysics Data System (ADS)

    Mikikian, Maxime; Couëdel, Lénaïc; Cavarroc, Marjorie; Tessier, Yves; Boufendi, Laïfa

    2010-08-01

    In complex plasmas, the trapped dust particle cloud is often characterized by a central dust-free region (“void”). The void induces a spatial inhomogeneity of the dust particle distribution and is at the origin of many intricate unstable phenomena. One type of this kind of behavior is the so-called heartbeat instability consisting of successive contractions and expansions of the void. This instability is characterized by a strong nonlinear dynamics which can reveal the occurrence of incomplete sequences corresponding to failed contractions. Experimental results based on high-speed imaging are presented for the first time and underline this threshold effect in both the dust cloud motion and the evolution of the plasma light emission.

  7. Critical and resonance phenomena in neural networks

    NASA Astrophysics Data System (ADS)

    Goltsev, A. V.; Lopes, M. A.; Lee, K.-E.; Mendes, J. F. F.

    2013-01-01

    Brain rhythms contribute to every aspect of brain function. Here, we study critical and resonance phenomena that precede the emergence of brain rhythms. Using an analytical approach and simulations of a cortical circuit model of neural networks with stochastic neurons in the presence of noise, we show that spontaneous appearance of network oscillations occurs as a dynamical (non-equilibrium) phase transition at a critical point determined by the noise level, network structure, the balance between excitatory and inhibitory neurons, and other parameters. We find that the relaxation time of neural activity to a steady state, response to periodic stimuli at the frequency of the oscillations, amplitude of damped oscillations, and stochastic fluctuations of neural activity are dramatically increased when approaching the critical point of the transition.

  8. Novel nuclear phenomena in quantum chromodynamics

    SciTech Connect

    Brodsky, S.J.

    1987-08-01

    Many of the key issues in understanding quantum chromodynamics involve processes in nuclear targets at intermediate energies. A range of hadronic and nuclear phenomena-exclusive processes, color transparency, hidden color degrees of freedom in nuclei, reduced nuclear amplitudes, jet coalescence, formation zone effects, hadron helicity selection rules, spin correlations, higher twist effects, and nuclear diffraction were discussed as tools for probing hadron structure and the propagation of quark and gluon jets in nuclei. Several areas were also reviewed where there has been significant theoretical progress determining the form of hadron and nuclear wave functions, including QCD sum rules, lattice gauge theory, and discretized light-cone quantization. A possible interpretation was also discussed of the large spin correlation A/sub NN/ in proton-proton scattering, and how relate this effect to an energy and angular dependence of color transparency in nuclei. 76 refs., 24 figs.

  9. Coherence Phenomena in Coupled Optical Resonators

    NASA Technical Reports Server (NTRS)

    Smith, David D.

    2007-01-01

    Quantum coherence effects in atomic media such as electromagnetically-induced transparency and absorption, lasing without inversion, super-radiance and gain-assisted superluminality have become well-known in atomic physics. But these effects are not unique to atoms, nor are they uniquely quantum in nature, but rather are fundamental to systems of coherently coupled oscillators. In this talk I will review a variety of analogous photonic coherence phenomena that can occur in passive and active coupled optical resonators. Specifically, I will examine the evolution of the response that can occur upon the addition of a second resonator, to a single resonator that is side-coupled to a waveguide, as the coupling is increased, and discuss the conditions for slow and fast light propagation, coupled-resonator-induced transparency and absorption, lasing without gain, and gain-assisted superluminal pulse propagation. Finally, I will discuss the application of these systems to laser stabilization and gyroscopy.

  10. Synchronization phenomena in human epileptic brain networks.

    PubMed

    Lehnertz, Klaus; Bialonski, Stephan; Horstmann, Marie-Therese; Krug, Dieter; Rothkegel, Alexander; Staniek, Matthäus; Wagner, Tobias

    2009-09-30

    Epilepsy is a malfunction of the brain that affects over 50 million people worldwide. Epileptic seizures are usually characterized by an abnormal synchronized firing of neurons involved in the epileptic process. In human epilepsy the exact mechanisms underlying seizure generation are still uncertain as are mechanisms underlying seizure spreading and termination. There is now growing evidence that an improved understanding of the epileptic process can be achieved through the analysis of properties of epileptic brain networks and through the analysis of interactions in such networks. In this overview, we summarize recent methodological developments to assess synchronization phenomena in human epileptic brain networks and present findings obtained from analyses of brain electromagnetic signals recorded in epilepsy patients. PMID:19481573

  11. Critical phenomena in N=2* plasma

    E-print Network

    A. Buchel; C. Pagnutti

    2010-10-16

    We use gauge theory/string theory correspondence to study finite temperature critical behaviour of mass deformed N=4 SU(N) supersymmetric Yang-Mills theory at strong coupling, also known as N=2* gauge theory. For certain range of the mass parameters, N=2* plasma undergoes a second-order phase transition. We compute all the static critical exponents of the model and demonstrate that the transition is of the mean-field theory type. We show that the dynamical critical exponent of the model is z=0, with multiple hydrodynamic relaxation rates at criticality. We point out that the dynamical critical phenomena in N=2* plasma is outside the dynamical universality classes established by Hohenberg and Halperin.

  12. Teaching wave phenomena via biophysical applications

    NASA Astrophysics Data System (ADS)

    Reich, Daniel; Robbins, Mark; Leheny, Robert; Wonnell, Steven

    2014-03-01

    Over the past several years we have developed a two-semester second-year physics course sequence for students in the biosciences, tailored in part to the needs of undergraduate biophysics majors. One semester, ``Biological Physics,'' is based on the book of that name by P. Nelson. This talk will focus largely on the other semester, ``Wave Phenomena with Biophysical Applications,'' where we provide a novel introduction to the physics of waves, primarily through the study of experimental probes used in the biosciences that depend on the interaction of electromagnetic radiation with matter. Topic covered include: Fourier analysis, sound and hearing, diffraction - culminating in an analysis of x-ray fiber diffraction and its use in the determination of the structure of DNA - geometrical and physical optics, the physics of modern light microscopy, NMR and MRI. Laboratory exercises tailored to this course will also be described.

  13. Reversion phenomena of Cu-Cr alloys

    NASA Technical Reports Server (NTRS)

    Nishikawa, S.; Nagata, K.; Kobayashi, S.

    1985-01-01

    Cu-Cr alloys which were given various aging and reversion treatments were investigated in terms of electrical resistivity and hardness. Transmission electron microscopy was one technique employed. Some results obtained are as follows: the increment of electrical resistivity after the reversion at a constant temperature decreases as the aging temperature rises. In a constant aging condition, the increment of electrical resistivity after the reversion increases, and the time required for a maximum reversion becomes shorter as the reversion temperature rises. The reversion phenomena can be repeated, but its amount decreases rapidly by repetition. At first, the amount of reversion increases with aging time and reaches its maximum, and then tends to decrease again. Hardness changes by the reversion are very small, but the hardness tends to soften slightly. Any changes in transmission electron micrographs by the reversion treatment cannot be detected.

  14. Hadronic and nuclear phenomena in quantum chromodynamics

    SciTech Connect

    Brodsky, S.J.

    1987-06-01

    Many of the key issues in understanding quantum chromodynamics involves processes at intermediate energies. We discuss a range of hadronic and nuclear phenomena - exclusive processes, color transparency, hidden color degrees of freedom in nuclei, reduced nuclear amplitudes, jet coalescence, formation zone effects, hadron helicity selection rules, spin correlations, higher twist effects, and nuclear diffraction - as tools for probing hadron structure and the propagation of quark and gluon jets in nuclei. Many of these processes can be studied in electroproduction, utilizing internal targets in storage rings. We also review several areas where there has been significant theoretical progress in determining the form of hadron and nuclear wavefunctions, including QCD sum rules, lattice gauge theory, and discretized light-cone quantization. 98 refs., 40 figs., 2 tabs.

  15. Critical phenomena in N=2* plasma

    SciTech Connect

    Buchel, Alex [Department of Applied Mathematics University of Western Ontario London, Ontario N6A 5B7 (Canada); Perimeter Institute for Theoretical Physics Waterloo, Ontario N2J 2W9 (Canada); Pagnutti, Chris [Department of Applied Mathematics University of Western Ontario London, Ontario N6A 5B7 (Canada)

    2011-02-15

    We use gauge theory/string theory correspondence to study finite temperature critical behavior of mass-deformed N=4 SU(N) supersymmetric Yang-Mills theory at strong coupling, also known as N=2* gauge theory. For a certain range of the mass parameters, N=2* plasma undergoes a second-order phase transition. We compute all the static critical exponents of the model and demonstrate that the transition is of the mean-field theory type. We show that the dynamical critical exponent of the model is z=0, with multiple hydrodynamic relaxation rates at criticality. We point out that the dynamical critical phenomena in N=2* plasma is outside the dynamical universality classes established by Hohenberg and Halperin.

  16. Bow Shock and Upstream Phenomena at Mars

    NASA Astrophysics Data System (ADS)

    Mazelle, C.; Winterhalter, D.; Sauer, K.; Trotignon, J. G.; Acuña, M. H.; Baumgärtel, K.; Bertucci, C.; Brain, D. A.; Brecht, S. H.; Delva, M.; Dubinin, E.; Øieroset, M.; Slavin, J.

    2004-03-01

    Mars Global Surveyor is the sixth spacecraft to return measurements of the Martian bow shock. The earlier missions were Mariner 4 (1964), Mars 2 and 3 (1972), Mars 5 (1975) and Phobos 2 (1989) (see reviews by Gringauz, 1981; Slavin and Holzer, 1982; Russell, 1985; Vaisberg, 1992a,b; Zakharov, 1992). Previous investigations of planetary bow shocks have established that their position, shape and jump conditions are functions of the upstream flow parameters and the nature of the solar wind — planet interaction (Spreiter and Stahara, 1980; Slavin et al., 1983; Russell, 1985). At Mars, however, the exact nature of the solar wind interaction was elusive due to the lack of low altitude plasma and magnetic field measurements (e.g., Axford, 1991). In fact our knowledge of the nature of the interaction of Mars with the solar wind was incomplete until the arrival of MGS and the acquisition of close-in magnetic field data (Acuña et al., 1998). As detailed by a series of review papers in this monograph, the Mars Global Surveyor (MGS) mission has now shown that the Mars environment is very complex with strong, highly structured crustal magnetic remnants in the southern hemisphere, while the northern hemisphere experiences the direct impingement of solar wind plasma. This review paper first presents a survey of the observations on the Martian bow shock and the upstream phenomena in the light of results from all the missions to date. It also discusses the kinetic properties of the Martian bow shock compared to the predictions of simulations studies. Then it examines the current status of understanding of these phenomena, including the possible sources of upstream low-frequency waves and the interpretations of localized disturbances in the upstream solar wind around Mars. Finally, it briefly discusses the open issues and questions that require further study.

  17. Intense phenomena during the winter of 1998/1999 in the northwestern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Hong, X.; Hodur, R. M.; Pascual, A.; Cummings, J. A.; Martin, P. J.

    2003-04-01

    The Northwestern Mediterranean Sea was characterized by intense weather and ocean phenomena during the winter of 1998/1999. This winter season exhibited very strong and prolonged periods of northwesterly winds (Mistral) with associated large losses of heat from the ocean due to enhanced surface buoyancy fluxes. Dense water formation occurred in the Gulf of Lion as the surface layer temperature dropped to 12 oC and the salinity increased to 38.2 psu. Hydrological and current data collected in 1999 revealed the spreading of newly formed deep water with unusual characteristics over the whole Algero-Provencal basin (Bethoux et al. 2002) and provided evidence of deep-water formation during the intense weather phenomenon. Sea surface topography from the TOPEX/Poseidon and ERS satellites, SST images derived from advanced very high resolution radiometer (AVHRR) sensors, and conductivity-temperature-depth (CTD) data collected during an oceanographic survey showed the presence of an intense anticyclonic eddy in the Balearic Sea from September 1998 to March 1999. The formation of this eddy is believed to be related to the transmission of anticyclonic vorticity from the shear of the strong Mistral (Pascual et al. 2002). To investigate these intense phenomena during the winter of 1998/1999, high-resolution (6-km) numerical simulations are conducted for the Mediterranean Sea using the US Navy Coastal Ocean Model (NCOM). The surface atmospheric forcing fields used in NCOM are from atmospheric reanalyses of the Mediterranean Sea area produced by the US Navy's Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPSTM). The reanalyzed fields include 10-m surface wind, surface wind stress, surface sensible and latent heat fluxes, solar and long-wave radiation at the surface, and accumulated precipitation. The temporal resolution of the atmospheric forcing fields is 1 hr and the horizontal resolution is 27 km. The simulations of these events are compared against all available observations. The mechanisms for the formation and development of the intense ocean phenomena during the winter of 1998/1999 are also investigated and discussed with sensitivity experiments under different atmospheric forcing.

  18. Local wind phenomena at the Waldstein/Weidenbrunnen FLUXNET site

    NASA Astrophysics Data System (ADS)

    Schier, S.; Meixner, F. X.; Foken, T.

    2009-04-01

    Two Intensive Observation Periods (IOP) of the EGER project (ExchanGE processes in mountainous Regions) were performed at the Waldstein/Weidenbrunnen FLUXNET site (DE-Bay) in the Fichtelgebirge/Germany. IOP1 was conducted in September and October 2007, IOP2 in June and July 2008. The project is focused on the detailed quantification of relevant processes within the soil-vegetation-atmosphere system by observing diurnal and annual cycles of energy, water and trace gases. The atmospheric boundary layer was profiled with an acoustic and radar remote sensing system (SODAR-RASS). The SODAR provided 10 minute mean profiles up to 500 m a.g.l. In contrast to IOP1 a second SODAR (referred to as miniSODAR) without a RASS-extension was used during IOP2 and provided 5 minute mean profiles up to 200 m a.g.l. The aims of this study included the observation of local wind phenomena at the site, the determination of their frequency and their relation to surrounding meteorological circumstances. During both IOPs some nocturnal low-level jets (LLJ) with a duration time of several hours were observed. Maximum horizontal wind speed (vhmax) was in the range from 11.5 to 12.3 m s-1 for IOP1 and in the range from 8.0 to 11.6 m s-1 for IOP2. The height of vhmax varied between 100 and 230 m a.g.l. Most of the LLJ events were characterised by an approaching flow from south-easterly directions. Another phenomenon was observed in the profile of the wind vector. It showed a strong turn of the wind direction with increasing height. At night times and during the morning hours flows above the canopy came from the east while the geostrophic wind approached from the south-westerly directions. The topography and resulting canalising effects seem to be the reason for the generation of LLJ as well as for the turn of the wind direction.

  19. The Role of Family Phenomena in Posttraumatic Stress in Youth

    PubMed Central

    Deatrick, Janet A.

    2010-01-01

    Topic Youth face trauma that can cause posttraumatic stress (PTS). Purpose 1). To identify the family phenomena used in youth PTS research; and 2). Critically examine the research findings regarding the relationship between family phenomena and youth PTS. Sources Systematic literature review in PsycInfo, PILOTS, CINAHL, and MEDLINE. Twenty-six empirical articles met inclusion criteria. Conclusion Measurement of family phenomena included family functioning, support, environment, expressiveness, relationships, cohesion, communication, satisfaction, life events related to family, parental style of influence, and parental bonding. Few studies gave clear conceptualization of family or family phenomena. Empirical findings from the 26 studies indicate inconsistent empirical relationships between family phenomena and youth PTS, though a majority of the prospective studies support a relationship between family phenomena and youth PTS. Future directions for leadership by psychiatric nurses in this area of research and practice are recommended. PMID:21344778

  20. Scientific Inquiry on Anomalous Atmospheric Light Phenomena: Past Research Gaps and New Methodological Goals

    NASA Astrophysics Data System (ADS)

    Teodorani, M.

    2009-12-01

    On the basis of the experience of this author, a decade of scientific research on earthlights is amply discussed and pondered from the point of view of instrumental measurements. After an introduction that shows a brief synthesis of what has been done so far, all the different measurement techniques and tactical/strategic procedures that have been used so far or that are planned for the near future are discussed in detail. Constructive criticism on the gaps that emerged from this research is punctually pointed out. New procedural ideas are widely proposed and scientifically motivated in order to improve this research and to stimulate researchers on this field in order to search for an optimum common protocol.

  1. Study of phenomena related to the sintering process of silicon nitride at atmospheric pressure

    NASA Technical Reports Server (NTRS)

    Bertani, A.

    1982-01-01

    A procedure was perfected for the production of components used in engineering applications of silicon nitride. Particles of complex geometry that combine remarkable mechanical properties with a high density are obtained. The process developed, in contrast to the "hot pressing" method, does not use external pressures, and in contrast to the reaction bonding method, final densities close to the theoretical value are obtained.

  2. FGK stars and T Tauri stars: Monograph series on nonthermal phenomena in stellar atmospheres

    NASA Technical Reports Server (NTRS)

    Cram, Lawrence E. (editor); Kuhi, Leonard V. (editor)

    1989-01-01

    The purpose of this book, FGK Stars and T Tauri Stars, like all other volumes of this series, is to exhibit and describe the best space data and ground based data currently available, and also to describe and critically evaluate the status of current theoretical models and physical mechanisms that have been proposed to interpret these data. The method for obtaining this book was to collect manuscripts from competent volunteer authors, and then to collate and edit these contributions to form a well structured book, which will be distributed to an international community of research astronomers by NASA and by the French CNRS.

  3. Astrophysical phenomena related to supermassive black holes

    NASA Astrophysics Data System (ADS)

    Pott, Jörg-Uwe

    2006-12-01

    The thesis contains the results of my recent projects in astrophysical research. All projects aim at pushing the limits of our knowledge about the interaction between a galaxy, the fundamental building block of today's universe, and a supermassive black hole (SMBH) at its center. Over the past years a lot of observational evidence has been gathered for the current understanding, that at least a major part of the galaxies with a stellar bulge contain central SMBHs. The typical extragalactic approach consists of searching for the spectroscopic pattern of Keplerian rotation, produced by stars and gas, when orbiting a central dark mass (Kormendy & Richstone 1995). It suggests that a significant fraction of large galaxies host in their very nucleus a SMBH of millions to billions of solar masses (Kormendy & Gebhardt 2001). In the closest case, the center of our Milky Way, the most central stars, which can be imaged, were shown to move on orbits with circulation times of a few decades only, evidencing a mass and compactness of the dark counter part of the Keplerian motion, which can only be explained by a SMBH (Eckart & Genzel 1996; Ghez et al. 2000; Schödel et al. 2002). Having acknowledged the widespread existence of SMBHs the obvious next step is investigating the interaction with their environment. Although the basic property of a SMBH, which is concentrating a huge amount of mass in a ludicrously small volume defined by the Schwarzschild radius, only creates a deep gravitational trough, its existence evokes much more phenomena than simply attracting the surrounding matter. It can trigger or exacerbate star formation via tidal forces (Morris 1993). It shapes the distribution of its surrounding matter to accretion discs, which themselves release gravitational potential energy as radiation, possibly due to magnetic friction (Blandford 1995). The radiation efficiency of such active galactic nuclei (AGN) can become roughly 100 times more efficient than atomic nuclear reactions in stars. In the most active galaxies known, the radiating accretion disc of the central SMBH engine easily outshines the stellar light of the entire galaxy (Blandford 1995). In addition to the light, plasma streams can emerge from the innermost regions at relativistic velocities, returning energy to the host galaxy (host) and creating jets and lobes with strong observational signatures, especially at radio and X-ray wavelengths (Wilson 2003). New insights in the wide field of SMBH/host interaction are often related to the development of new, more sensitive instruments and telescopes. For example the idea, that a high luminosity AGN may result from a merger event between two galaxies, could only develop with the upcoming high resolution and sensitive imaging capabilities needed to detect the highly distorted host galaxy morphologies of (post-)merger galaxies (Heckman et al. 1986). Furthermore multi-wavelength approaches, which combine the results of measurements at different wavelengths, often lead to new conclusions or confirm unsecured hypotheses. Thus developing a new instrument can be as valuable as combining different datasets. I follow both approaches and developed projects which (i) deal with new instrumentation and telescope technology, (ii) combine datasets from different wavelengths and resolutions, and (iii) incorporate recent theoretical models and predictions, which can be verified empirically. While some projects are more focused on investigating the power of new observational techniques, others incorporate acknowledged instruments to probe predictions based on previous observations and models and trace special phenomena of SMBH/host interaction. But in most cases aspects of all three items appear. The SMBH/host interaction results in phenomena at all linear size scales of the system, from the direct accretion of matter onto the central black hole up to radio jets crossing the entire galaxy. Thus interaction effects do not simply concentrate on the innermost region of a galaxy. Furthermore an increasing number of apparently tota

  4. Pathways toward understanding Macroscopic Quantum Phenomena

    NASA Astrophysics Data System (ADS)

    Hu, B. L.; Suba?i, Y.

    2013-06-01

    Macroscopic quantum phenomena refer to quantum features in objects of 'large' sizes, systems with many components or degrees of freedom, organized in some ways where they can be identified as macroscopic objects. This emerging field is ushered in by several categories of definitive experiments in superconductivity, electromechanical systems, Bose-Einstein condensates and others. Yet this new field which is rich in open issues at the foundation of quantum and statistical physics remains little explored theoretically (with the important exception of the work of A J Leggett [1], while touched upon or implied by several groups of authors represented in this conference. Our attitude differs in that we believe in the full validity of quantum mechanics stretching from the testable micro to meso scales, with no need for the introduction of new laws of physics.) This talk summarizes our thoughts in attempting a systematic investigation into some key foundational issues of quantum macroscopic phenomena, with the goal of ultimately revealing or building a viable theoretical framework. Three major themes discussed in three intended essays are the large N expansion [2], the correlation hierarchy [3] and quantum entanglement [4]. We give a sketch of the first two themes and then discuss several key issues in the consideration of macro and quantum, namely, a) recognition that there exist many levels of structure in a composite body and only by judicious choice of an appropriate set of collective variables can one give the best description of the dynamics of a specific level of structure. Capturing the quantum features of a macroscopic object is greatly facilitated by the existence and functioning of these collective variables; b) quantum entanglement, an exclusively quantum feature [5], is known to persist to high temperatures [6] and large scales [7] under certain conditions, and may actually decrease with increased connectivity in a quantum network [8]. We use entanglement as a measure of quantumness here and pick out these somewhat counter-intuitive examples to show that there are blind spots worthy of our attention and issues which we need to analyze closer. Our purpose is to try to remove the stigma that quantum only pertains to micro, in order to make way for deeper probes into the conditions whereby quantum features of macroscopic systems manifest.

  5. Living matter: the "lunar eclipse" phenomena.

    PubMed

    Korpan, Nikolai N

    2010-01-01

    The present investigations describe a unique phenomenon, namely the phenomenon of the "lunar eclipse", which has been observed and discovered by the author in living substance during the freeze-thawing processes in vivo using temperatures of various intensities and its cryosurgical response in animal experiment. Similar phenomena author has observed in nature, namely the total lunar eclipse and total solar eclipse. In this experimental study 76 animals (mongrel dogs) were investigated. A disc cryogenic probe was placed on the pancreas after the laparotomy. For cryosurgical exposure a temperature range of -40 degrees C, -80 degrees C, -120 degrees C and -180 degrees C was selected in contact with pancreas parenchyma. The freeze-thaw cycle was monitored by intraoperative ultrasound before, during and after cryosurgery. Each cryolesion was observed for one hour after thawing intraoperatively. Immediately after freezing, during the thawing process, the snow-white pancreas parenchyma, frozen hard to an ice block and resembling a full moon with a sharp demarcation line, gradually assumed a ruby-red shade and a hemispherical shape as it grew in size depend on reconstruction vascular circulation from the periphery to the center. This snow-white cryogenic lesion dissolved in the same manner in all animal tissues. The "lunar eclipse" phenomenon contributes to a fundamental understanding of the mechanisms of biological tissue damage during low temperature exposure in cryoscience and cryomedicine. Properties of the pancreas parenchyma response during the phenomenon of the "lunar eclipse" provide important insights into the mechanisms of damage and the formation of cryogenic lesion immediately after thawing in cryosurgery. Vascular changes and circulatory stagnation are commonly considered to be the main mechanism of biological tissue injury during low temperature exposure. The phenomenon of the "lunar eclipse" suggests that cryosurgery is the first surgical technique to use anti-angiogenesis with an immediately following cryoaponecrosis and cryoapoptosis in the treatment of malignant tumor. Both the "lunar eclipse" in vivo as well as the similar phenomena, namely the total moon and total solar lunar eclipses, are is part of living nature. PMID:21485756

  6. Experiments to investigate direct containment heating phenomena with scaled models of the Surry Nuclear Power Plant

    SciTech Connect

    Blanchat, T.K.; Allen, M.D.; Pilch, M.M. [Sandia National Labs., Albuquerque, NM (United States); Nichols, R.T. [Ktech Corp., Albuquerque, NM (United States)

    1994-06-01

    The Containment Technology Test Facility (CTTF) and the Surtsey Test Facility at Sandia National Laboratories are used to perform scaled experiments that simulate High Pressure Melt Ejection accidents in a nuclear power plant (NPP). These experiments are designed to investigate the effects of direct containment heating (DCH) phenomena on the containment load. High-temperature, chemically reactive melt (thermite) is ejected by high-pressure steam into a scale model of a reactor cavity. Debris is entrained by the steam blowdown into a containment model where specific phenomena, such as the effect of subcompartment structures, prototypic air/steam/hydrogen atmospheres, and hydrogen generation and combustion, can be studied. Four Integral Effects Tests (IETs) have been performed with scale models of the Surry NPP to investigate DCH phenomena. The 1/61{sup th} scale Integral Effects Tests (IET-9, IET-10, and IET-11) were conducted in CTRF, which is a 1/6{sup th} scale model of the Surry reactor containment building (RCB). The 1/10{sup th} scale IET test (IET-12) was performed in the Surtsey vessel, which had been configured as a 1/10{sup th} scale Surry RCB. Scale models were constructed in each of the facilities of the Surry structures, including the reactor pressure vessel, reactor support skirt, control rod drive missile shield, biological shield wall, cavity, instrument tunnel, residual heat removal platform and heat exchangers, seal table room and seal table, operating deck, and crane wall. This report describes these experiments and gives the results.

  7. Atomic and nuclear interference phenomena and their applications 

    E-print Network

    Kuznetsova, Yelena Anatolyevna

    2005-08-29

    In this work, interference and coherence phenomena, appearing in atomic and molecular ensembles interacting with coherent light sources, as electromagnetically induced transparency (EIT), coherent population trapping (CPT), ...

  8. Positive muscle phenomena--diagnosis, pathogenesis and associated disorders.

    PubMed

    Kortman, Hans G; Veldink, Jan H; Drost, Gea

    2012-02-01

    Positive muscle phenomena arise owing to various forms of spontaneous muscle hyperactivity originating in motor neurons or in the muscle itself. Although they are common in a wide range of neurological and non-neurological diseases, clinical and scientific data on these phenomena are limited, and their presence is sometimes overlooked. This gap in our knowledge hampers effective diagnosis and treatment. In this article, we review the clinical characteristics and approach to diagnosis of the various positive muscle phenomena, and discuss their genetic underpinnings and pathophysiological mechanisms. Finally, we outline an algorithm to discriminate between the different positive muscle phenomena. PMID:22270020

  9. ENG ME/MS 527 Transport Phenomena Catalog Data

    E-print Network

    to transport phenomena and its applications in various fields such as materials science, electrochemistry situations encountered in materials science, electrochemistry, mechanical engineering, chemicals processing

  10. Recognizing hesitation phenomena in continuous, spontaneous speech

    NASA Astrophysics Data System (ADS)

    Oshaughnessy, Douglas

    Spontaneous speech differs from read speech in speaking rate and hesitation. In natural, spontaneous speech, people often start talking and then think along the way; at times, this causes the speech to have hesitation pauses (both filled and unfilled) and restarts. Results are reported on all types of pauses in a widely-used speech database, for both hesitation pauses and semi-intentional pauses. A distinction is made between grammatical pauses (at major syntactic boundaries) and ungrammatical ones. Different types of unfilled pauses cannot be reliably separated based on silence duration, although grammatical pauses tend to be longer. In the prepausal word before ungrammatical pauses, there were few continuation rises in pitch, whereas 80 percent of the grammatical pauses were accompanied by a prior fundamental frequency rise of 10-40 kHz. Identifying the syntactic function of such hesitation phenomena can improve recognition performance by eliminating from consideration some of the hypotheses proposed by an acoustic recognizer. Results presented allow simple identification of filled pauses (such as uhh, umm) and their syntactic function.

  11. Rotary kilns - transport phenomena and transport processes

    SciTech Connect

    Boateng, A.

    2008-01-15

    Rotary kilns and rotating industrial drying ovens are used for a wide variety of applications including processing raw minerals and feedstocks as well as heat-treating hazardous wastes. They are particularly critical in the manufacture of Portland cement. Their design and operation is critical to their efficient usage, which if done incorrectly can result in improperly treated materials and excessive, high fuel costs. This book treats all engineering aspects of rotary kilns, including thermal and fluid principles involved in their operation, as well as how to properly design an engineering process that uses rotary kilns. Chapter 1: The Rotary Kiln Evolution and Phenomenon Chapter 2: Basic Description of Rotary Kiln Operation Chapter 3: Freeboard Aerodynamic Phenomena Chapter 4: Granular Flows in Rotary Kilns Chapter 5: Mixing and Segregation Chapter 6: Combustion and Flame - includes section on types of fuels used in rotary kilns, coal types, ranking and analysis, petroleum coke combustion, scrap tire combustion, pulverized fuel (coal/coke) firing in kilns, pulverized fuel delivery and firing systems. Chapter 7: Freeboard Heat Transfer Chapter 8: Heat Transfer Processes in the Rotary Kiln Bed Chapter 9: Mass and Energy Balance Chapter 10: Rotary Kiln Minerals Process Applications.

  12. Further shock tunnel studies of scramjet phenomena

    NASA Technical Reports Server (NTRS)

    Morgan, R. G.; Paull, A.; Morris, N. A.; Stalker, R. J.

    1986-01-01

    Scramjet phenomena were studied using the shock tunnel T3 at the Australian National University. Simple two dimensional models were used with a combination of wall and central injectors. Silane as an additive to hydrogen fuel was studied over a range of temperatures and pressures to evaluate its effect as an ignition aid. The film cooling effect of surface injected hydrogen was measured over a wide range of equivalence. Heat transfer measurements without injection were repeated to confirm previous indications of heating rates lower than simple flat plate predictions for laminar boundary layers in equilibrium flow. The previous results were reproduced and the discrepancies are discussed in terms of the model geometry and departures of the flow from equilibrium. In the thrust producing mode, attempts were made to increase specific impulse with wall injection. Some preliminary tests were also performed on shock induced ignition, to investigate the possibility in flight of injecting fuel upstream of the combustion chamber, where it could mix but not burn.

  13. Ultrashort Phenomena in Biochemistry and Biological Signaling

    NASA Astrophysics Data System (ADS)

    Splinter, Robert

    2014-11-01

    In biological phenomena there are indications that within the long pulse-length of the action potential on millisecond scale, there is additional ultrashort perturbation encoding that provides the brain with detailed information about the origin (location) and physiological characteristics. The objective is to identify the mechanism-of-action providing the potential for encoding in biological signal propagation. The actual molecular processes involved in the initiation of the action potential have been identified to be in the femtosecond and pico-second scale. The depolarization process of the cellular membrane itself, leading to the onset of the actionpotential that is transmitted to the brain, however is in the millisecond timeframe. One example of the femtosecond chemical interaction is the photoresponse of bacteriorhodopsin. No clear indication for the spatial encoding has so far been verified. Further research will be required on a cellular signal analysis level to confirm or deny the spatial and physiological encoding in the signal wave-trains of intercellular communications and sensory stimuli. The pathological encoding process for cardiac depolarization is however very pronounced and validated, however this electro-chemical process is in the millisecond amplitude and frequency modulation spectrum.

  14. The Monitoring of Transient Lunar Phenomena

    NASA Astrophysics Data System (ADS)

    Doorn, Jarrel; Eaton, M.; Ahrendts, G.; Barker, T.

    2011-05-01

    Transient Lunar Phenomena (TLP's) are described as short-lived changes in the brightness of areas on the face of the Moon. TLP activity has a higher number of reports, though unsubstantiated, in specific areas of the Moon such as the Aristarchus plateau. Our current research includes the division of lunar images taken through multiple filters using a Santa-Barbara Instrument Group (SBIG) ST8-E CCD camera mounted on a 0.45m Centurion telescope. We are also taking spectra of regions such as Aristarchus and the crater Ina, which shows evidence of recent activity (Schultz, P., Staid, M., Pieters, C. Nature, Volume 444, Issue 7116, pp. 184-186, 2006) using an SBIG DSS-7 spectrometer mounted on a 0.30m Schmidt-Cassegrain optical tube assembly on a Software Bisque Paramount drive system. Future research will include infrared imaging of the lunar surface. We are grateful for the support provided by the NASA Rhode Island Space Grant Consortium and the National Geographic Society.

  15. Investigations of cathode phenomena in pseudospark discharges

    NASA Astrophysics Data System (ADS)

    Felsner, P.; Stetter, M.; Hartmann, W.; Linsenmeyer, A.; Christiansen, J.; Frank, K.

    1994-11-01

    The cathode phenomena during the conduction phase of a pseudospark discharge are investigated with different cathode materials: Cu, Mo, Ni, Ta, and W/Re. The discharge gas was hydrogen with a gas pressure of 40 Pa. At a pulse duration of 2.7 microsecond and a maximum current of 9 kA, i.e., at a transferred charge of 11 mC/discharge, mass erosion rates of the cathode materials showed no significant material dependence after 10(exp 6) discharges. Fast framing photography (end-on, exposure time: 5 ns) of the light emission from the cathode surface revealed several small spots simultaneously, distributed over a cathode surface of 1 sq cm. The distribution of metal and hydrogen spectral lines at the cathode surface and in the gap were compared. Metal lines are localized on the cathode surface, whereas the hydrogen Balmer beta-line is diffuse over the electrodes surfaces and the gap. Polished electrodes showed, after a single pulse, about 10(exp 7) craters with 0.5-5 micrometer diameter. This is leading to a local current density of about 10(exp 8) A/sq cm in a single crater.

  16. New theoretical treatment of ion resonance phenomena.

    PubMed

    Vincze, G; Szasz, A; Liboff, A R

    2008-07-01

    Despite experimental evidence supporting ICR-like interactions in biological systems, to date there is no reasonable theoretical explanation for this phenomenon. The parametric resonance approach introduced by Lednev has enjoyed limited success in predicting the response as a function of the ratio of AC magnetic intensity to that of the DC field, explaining the results in terms of magnetically induced changes in the transition probability of calcium binding states. In the present work, we derive an expression for the velocity of a damped ion with arbitrary q/m under the influence of the Lorentz force. Series solutions to the differential equations reveal transient responses as well as resonance-like terms. One fascinating result is that the expressions for ionic drift velocity include a somewhat similar Bessel function dependence as was previously obtained for the transition probability in parametric resonance. However, in the present work, not only is there an explicit effect due to damping, but the previous Bessel dependence now occurs as a subset of a more general solution, including not only the magnetic field AC/DC ratio as an independent variable, but also the ratio of the cyclotronic frequency Omega to the applied AC frequency omega. In effect, this removes the necessity to explain the ICR interaction as stemming from ion-protein binding sites. We hypothesize that the selectively enhanced drift velocity predicted in this model can explain ICR-like phenomena as resulting from increased interaction probabilities in the vicinity of ion channel gates. PMID:18288680

  17. Near Critical Phenomena in Laminar Boundary Layers

    NASA Astrophysics Data System (ADS)

    Kluwick, A.; Braun, S.; Cox, E. A.

    Recent developments in the construction of airfoils and rotorblades are characterized by an increasing interest in the application of so-called smart structures for active flow control. These are characterized by an interplay of sensors, actuators, real-time controlling data processing systems and the use of new materials e.g. shape alloys with the aim to increase manoeuvrability, reduce drag and radiated sound. The optimal use of such devices obviously requires a detailed insight into the flow phenomena to be controlled and in particular their sensitivity to external disturbances. In this connection locally separated boundary layer flows are of special interest. Asymptotic analysis of boundary layer separation in the limit of large Reynolds number Re? ? has shown that in a number of cases which are of importance from a practical point of view solutions of the resulting interaction equations describing two-dimensional steady flows exist up to a limiting value ? c of the relevant controlling parameter ? only while two branches of solutions exist in a regime ? < ? c . The present study aims at a better understanding of near critical flows ? ? — ? c ? ? 0 and in particular the changes of the flow behaviour associated with the passage of ? through ? c .

  18. Physics of the Sun and its Atmosphere

    NASA Astrophysics Data System (ADS)

    Dwivedi, B. N.; Narain, U.

    ch. 1. Recent advances in solar physics / B. N. Dwivedi -- ch. 2. Overview of the Sun / S. S. Hasan -- ch. 3. Seismic view of the Sun / S. M. Chitre and B. N. Dwivedi -- ch. 4. Solar magnetism / P. Venkatakrishnan and S. Gosain -- ch. 5. Waves and oscillations in the solar atmosphere / R. Erdélyi -- ch. 6. VUV spectroscopy of solar plasma / A. Mohan -- ch. 7. Active region diagnostics / H. E. Mason and D. Tripathi -- ch. 8. Hall effect and ambipolar diffusion in the lower solar atmosphere / V. Krishan -- ch. 9. On solar coronal heating mechanisms / K. Pandey and U. Narain -- ch. 10. Coronal mass ejections (CMEs) and associated phenomena / N. Srivastava -- ch. 11. The radio Sun / P. K. Manoharan -- ch. 12. The solar wind / P. K. Manoharan -- ch. 13. The Sun-Earth system: our home in space / J. L. Lean.

  19. Atmospheric Nitrogen Fluorescence Yield

    NASA Technical Reports Server (NTRS)

    Adams, J. H., Jr.; Christl, M. J.; Fountain, W. F.; Gregory, J. C.; Martens, K. U.; Sokolsky, Pierre; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Several existing and planned experiments estimate the energies of ultra-high energy cosmic rays from air showers using the atmospheric nitrogen fluorescence. The nitrogen fluorescence yield from air shower electrons depends on the atmospheric composition. We will discuss the uncertainties in the fluorescence yield form electrons in the real atmosphere and describe a concept for a small balloon payload to measure the atmospheric fluorescence yield as a function of attitude.

  20. Individualization of the anisotropic phenomena of the imbalanced Nature

    NASA Astrophysics Data System (ADS)

    Shlafman, L. M.; Kontar, V. A.

    2013-05-01

    What is an individual phenomenon of Nature? Where are the boundaries? Why it is considered as an individual phenomenon? etc. People cannot directly detect the "something isotropic." Sometimes we notice that there is a "black box." But on closer inspection, especially with new methods, the "black box" began to lighten. It seems that his "blackness" is the result of imperfect human sensors and interpretations, but not a phenomenon of Nature. Really people can identify only the anisotropic phenomena of Nature, but with the significant errors. Let's take a look at our home planet Earth. Where are the borders of our planet? It is may seem as the very simple question. People walk on the land and swim on the seas. This is the border on the surface of land and water. But what is about the dust? The dust is a part of the land, which is in the air. Weight of dust is very small compared to the weight of the planet. But it is the dust has formed valleys. Dust can rise very high above the planet's surface and even fly into the space. A similar situation is with the water. The bulk of the liquid water is in surface and underground waters. Water vapor is in the atmosphere. Atmospheric water is much less than on the earth and under the earth. But atmospheric water plays a huge role in the world and even extends into the space. Without a full accounting of dust and water impossible correctly describe the planet. But with considering the dust and water the planet is not solid-liquid ball. It is like "fuzzy blowball" with the boundaries that go to infinity. This "fuzziness" refers to gravity. The gravitational field does not end in the Lagrange points. This "fuzziness" illustrated by the electro-magnetic fields, etc. Our planet can be seen as a multidimensional anisotropic phenomenon of Nature. The anisotropy precisely is, and therefore is the gradient and movement. This phenomenon is clearly imbalanced because nothing ever repeats itself exactly, etc. The borders of any anisotropic imbalanced natural phenomenon can be determined with the precision which allow the sensors and methods of interpretation. The desire to identify the separate object in the imbalanced continuous Nature is the consequence of personalized thinking of people. In Nature is not exists any separate and independent phenomenon. In Nature are exist only the more or less concentrated anisotropy, which are constantly changing in the infinite continuity. Some references: Vladimir A Kontar, Federal GEOS Funding, US: 1. What is Imbalance of Nature? 2. What is the Imbalance of Water in Nature? 3. The Imbalance of Water in Nature as System 4. Axiomatic of the Imbalance of Nature and the Imbalance of Water in Nature 5. Water Management on the Verge of the Imbalanced Revolution 6. Control the Imbalance in Nature for Humanity Survival 7. Proof of the Imbalance of Nature in the Universe 8. Imbalanced Logic as the next level development of science Vladimir A. Kontar, Lyubov M. Shlafman, Federal GEOS Funding, US: 1. The relativity theory of the imbalance of water in nature 2. Redeployment as a Parameter to Measure the Imbalance of Water in Nature 4. Imbalance's Hypothesis for the Origin and Dynamics of Water on the Terrestrial Planets 5. Imbalance of Water and Carbon as Factors of the Global Climate Changes

  1. Dynamics of Atmospheres

    E-print Network

    Read, Peter L.

    . Houghton - The Physics of Atmospheres (CUP) ALSO · I. N. James - Introduction to Circulating Atmospheres (CUP) · P. L. Read & S. R. Lewis - The Martian Climate Revisited (Springer-Praxis) #12;Atmospheric and sublimation (NB peculiar to Mars) · Radiatively interactive dust transport, lifting and deposition · Water

  2. Nonisothermal Pluto atmosphere models

    Microsoft Academic Search

    W. B. Hubbard; R. V. Yelle; J. I. Lunine

    1990-01-01

    The present thermal profile calculation for a Pluto atmosphere model characterized by a high number fraction of CH4 molecules encompasses atmospheric heating by solar UV flux absorption and conductive transport cooling to the surface of Pluto. The stellar occultation curve predicted for an atmosphere of several-microbar surface pressures (which entail the existence of a substantial temperature gradient close to the

  3. Computational Atmospheric Science

    NSDL National Science Digital Library

    The Shodor Education Foundation, Inc.

    The goal of this online instructional workshop is to introduce participants to the theories and applications of atmospheric science computer modeling, specifically ozone formation and reactions in the atmosphere. Upon completion of the course, participants should understand the fundamental principles of ozone formation in the atmosphere and be able to understand and use numerical and computational science methods to study ozone science.

  4. Neutral gas plasma interactions and critical ionization velocity phenomena

    Microsoft Academic Search

    K. Papadopoulos

    1983-01-01

    The interplay of collisional and collisionless phenomena in the interaction of a magnetoplasma streaming through neutral gas produces some of the most fascinating plasma physics phenomena. A key notion controlling such interactions is the existence of a critical velocity (U sub c) effect postulated in an ad hoc fashion by Alfven, in his model of the formation of the solar

  5. Transport Phenomena in Polymer Electrolyte Membranes Jeffrey Anders Fimrite

    E-print Network

    Victoria, University of

    Transport Phenomena in Polymer Electrolyte Membranes by Jeffrey Anders Fimrite B.Eng., University a thorough review of the available literature on issues relevant to transport phenomena in polymer of the BFCM model and the associated transport model is that by fitting the BFCM to conductivity data we

  6. The Evolution of Altruism by Kin Selection: New Phenomena With

    E-print Network

    Rose, Michael R.

    The Evolution of Altruism by Kin Selection: New Phenomena With Strong Selection Laurence D. Mueller in a population of egoists involves diiculties similar to the Initial increase of altruism. Clustering and other species of animals. Although the meaning of "altruism" may vary, we first illustrate the phenomena

  7. RENDERING THE PHENOMENA OF VOLUME ABSORPTION IN HOMOGENEOUS TRANSPARENT MATERIALS

    E-print Network

    Drew, Mark S.

    expands the capability of rendering natural phenomena and can be used to improve the realism of computer generated imagery. Keywords: Volume absorption, natural phenomena, transparent materials, colors, ray, and liquid solutions (dye or chemical) are all examples of homogeneous transparent objects. The principle

  8. 3D dynamical networks to emulate complex neural phenomena

    Microsoft Academic Search

    Maide Bucolo; Francesca Conti; Luigi Fortuna; Mattia Frasca

    2005-01-01

    Visual hallucinations have been described several times, but the causes that produces hallucinations are unknown. These kinds of studies are important because these phenomena do not appears only in people affected by mental illnesses; in the last years hallucinations have been reported by astronauts in several space missions. The generation of such phenomena can be dealt with by studying the

  9. PREFACE: XI Latin American Workshop on Nonlinear Phenomena

    Microsoft Academic Search

    Celia Anteneodo; Marcos G. E. da Luz

    2010-01-01

    The XI Latin American Workshop on Nonlinear Phenomena (LAWNP) has been held in Búzios-RJ, Brazil, from 5-9 October 2009. This international conference is one in a series that have gathered biennially, over the past 21 years, physicists and other scientists who direct their work towards several aspects of nonlinear phenomena and complex systems. The main purpose of LAWNP meetings is

  10. Field dependence, suggestibility and belief in paranormal phenomena

    Microsoft Academic Search

    Andreas Hergovich

    2003-01-01

    This paper examines the relationships between field dependence, suggestibility and belief in paranormal phenomena. In Experiment 1, 91 subjects underwent an hypnosis session to determine their suggestibility. They also completed a paranormal belief scale and a computer test of field dependence. It was shown that suggestibility and field dependence had positive and significant correlations with the belief in paranormal phenomena.

  11. CHAPTER 1. COLLECTIVE PLASMA PHENOMENA 1 Collective Plasma

    E-print Network

    Callen, James D.

    CHAPTER 1. COLLECTIVE PLASMA PHENOMENA 1 Chapter 1 Collective Plasma Phenomena The properties of a medium are determined by the microscopic processes in it. In a plasma the microscopic processes is actually limited to a distance of order the Debye length in a plasma. On length scales longer than

  12. Cold spray deposition: Significance of particle impact phenomena

    Microsoft Academic Search

    Sergei Vladimirovich Klinkov; Vladimir Fedorovich Kosarev; Martin Rein

    2005-01-01

    A survey of particle impact phenomena is provided with a particular emphasis on impacts resulting in the so-called cold spray phenomenon, i.e., in a strong adherence of particles to the impacted surface. A classification of impact phenomena is made based on particle size and impact velocity. Impact features characteristic of cold sprays are compared with typical features of impacts occurring

  13. Atmospheric Pressure Indicator.

    ERIC Educational Resources Information Center

    Salzsieder, John C.

    1995-01-01

    Discusses observable phenomena related to air pressure. Describes a simple, unobtrusive, semiquantitative device to monitor the changes in air pressure that are associated with altitude, using a soft-drink bottle and a balloon. (JRH)

  14. Nonisothermal Pluto atmosphere models

    SciTech Connect

    Hubbard, W.B.; Yelle, R.V.; Lunine, J.I. (Arizona Univ., Tucson (USA))

    1990-03-01

    The present thermal profile calculation for a Pluto atmosphere model characterized by a high number fraction of CH4 molecules encompasses atmospheric heating by solar UV flux absorption and conductive transport cooling to the surface of Pluto. The stellar occultation curve predicted for an atmosphere of several-microbar surface pressures (which entail the existence of a substantial temperature gradient close to the surface) agrees with observations and implies that the normal and tangential optical depth of the atmosphere is almost negligible. The minimum period for atmospheric methane depletion is calculated to be 30 years. 29 refs.

  15. Therapeutic potential of atmospheric neutrons

    PubMed Central

    Voyant, Cyril; Roustit, Rudy; Tatje, Jennifer; Biffi, Katia; Leschi, Delphine; Briançon, Jérome; Marcovici, Céline Lantieri

    2010-01-01

    Background Glioblastoma multiform (GBM) is the most common and most aggressive type of primary brain tumour in humans. It has a very poor prognosis despite multi-modality treatments consisting of open craniotomy with surgical resection, followed by chemotherapy and/or radiotherapy. Recently, a new treatment has been proposed – Boron Neutron Capture Therapy (BNCT) – which exploits the interaction between Boron-10 atoms (introduced by vector molecules) and low energy neutrons produced by giant accelerators or nuclear reactors. Methods The objective of the present study is to compute the deposited dose using a natural source of neutrons (atmospheric neutrons). For this purpose, Monte Carlo computer simulations were carried out to estimate the dosimetric effects of a natural source of neutrons in the matter, to establish if atmospheric neutrons interact with vector molecules containing Boron-10. Results The doses produced (an average of 1 ?Gy in a 1 g tumour) are not sufficient for therapeutic treatment of in situ tumours. However, the non-localised yet specific dosimetric properties of 10B vector molecules could prove interesting for the treatment of micro-metastases or as (neo)adjuvant treatment. On a cellular scale, the deposited dose is approximately 0.5 Gy/neutron impact. Conclusion It has been shown that BNCT may be used with a natural source of neutrons, and may potentially be useful for the treatment of micro-metastases. The atmospheric neutron flux is much lower than that utilized during standard NBCT. However the purpose of the proposed study is not to replace the ordinary NBCT but to test if naturally occurring atmospheric neutrons, considered to be an ionizing pollution at the Earth's surface, can be used in the treatment of a disease such as cancer. To finalize this study, it is necessary to quantify the biological effects of the physically deposited dose, taking into account the characteristics of the incident particles (alpha particle and Lithium atom) and radio-induced effects (by-stander and low dose effect). One of the aims of the presented paper is to propose to experimental teams (which would be interested in studying the phenomena) a simple way to calculate the dose deposition (allometric fit of free path, transmission factor of brain). PMID:24669300

  16. An Atmospheric Science Observing System Simulation Experiment (OSSE) Environment

    NASA Technical Reports Server (NTRS)

    Lee, Meemong; Weidner, Richard; Qu, Zheng; Bowman, Kevin; Eldering, Annmarie

    2010-01-01

    An atmospheric sounding mission starts with a wide range of concept designs involving measurement technologies, observing platforms, and observation scenarios. Observing system simulation experiment (OSSE) is a technical approach to evaluate the relative merits of mission and instrument concepts. At Jet Propulsion Laboratory (JPL), the OSSE team has developed an OSSE environment that allows atmospheric scientists to systematically explore a wide range of mission and instrument concepts and formulate a science traceability matrix with a quantitative science impact analysis. The OSSE environment virtually creates a multi-platform atmospheric sounding testbed (MAST) by integrating atmospheric phenomena models, forward modeling methods, and inverse modeling methods. The MAST performs OSSEs in four loosely coupled processes, observation scenario exploration, measurement quality exploration, measurement quality evaluation, and science impact analysis.

  17. Interlayer interaction phenomena in novel materials

    NASA Astrophysics Data System (ADS)

    Pershoguba, Sergii

    Recently, there has been a considerable interest in various novel two-dimensional (2D) materials, such as graphene, topological insulators, etc. These materials host a plethora of exotic phenomena owing to their unconventional electronic structure. Physics of these 2D materials is understood fairly well, so a natural generalization is to assemble these materials into three-dimensional (3D) stacks. In this thesis, we study a number of multilayer systems, where the interlayer interaction plays a salient role. We commence with studying graphene multilayers coupled via interlayer tunneling amplitude. We calculate the energy spectrum of the system in magnetic field B parallel to the layers. The parallel magnetic field leads to a relative gauge shift of the momentum spaces of the individual 2D layers. When the interlayer tunneling is introduced, we find the Landau levels. We observe two qualitatively distinct domains in the Landau spectrum and analyze them using semiclassical arguments. Then, we include electric field E perpendicular to the layers, and analyze the spectrum in the crossed-field geometry. If the fields are in resonance E = upsilon B, where upsilon is the velocity of carriers in graphene, the wave-functions delocalize in the direction along the field E. We compare this prediction to a tunneling spectroscopy study of a graphite mesa in the parallel magnetic field. Indeed, the tunneling spectrum displays a peak, which grows linearly with the applied magnetic field B, and is, thus, consistent with our theoretical analysis. Then, we move on to a discussion of Z2 topological insulators within the Shockley model. We generalize the one dimensional (1D) Shockley model by replacing atomic sites of the original model by the 2D Rashba spin-orbit layers. We analyze surface states of a topological insulator using a construction of vortex lines in the 3D momentum space. We also study a topological insulator in a thin film geometry, where the opposite surface states are coupled by the tunneling amplitude. We calculate the tunneling current between the opposite surfaces and a spin polarization of the current as a function of the in-plane magnetic field. We conclude with studying a novel chiral order in cuprates. We construct a helical interlayer pattern of loop-currents. The interlayer magnetic coupling and magnetoelectric effect lead to optical gyrotropy.

  18. Solidification phenomena in metal matrix nanocomposites

    NASA Astrophysics Data System (ADS)

    de Cicco, Michael Peter

    2009-12-01

    Nanoparticles in metal matrix nanocomposites (MMNCs) were shown to act as catalysts for nucleation of solidification of the matrix alloy, as well as to alter the intermetallic phase formation. These phenomena were studied in zinc, aluminum, and magnesium alloys. In all alloys studied, a refinement of the microstructure was seen with the addition of the nanoparticles. Various types of nanoparticles were used and had varying degrees of refinement. In a zinc alloy, AC43A, SiC, TiC, and Al2O3 gamma nanoparticles were all found to refine the alloy. Thermal analysis of bulk samples showed the onset of solidification at reduced undercoolings, indicating nucleation catalysis. Nucleation of the primary phase was also observed by employing the droplet emulsion technique (DET). DET results showed that the secondary phase nucleation was also catalyzed by the nanoparticles. Exploiting the nucleation catalysis of the nanoparticles and the associated grain refinement, a semi-solid casting (SSC) process was demonstrated in AC43A + SiC nanocomposites. This novel process successfully incorporated the strength enhancement of MMNCs and the casting quality benefits of SSC. This process required no additional processing steps or material handling typical of existing SSC processes. The nucleation catalysis of the nanoparticles was sufficient to create semi-solid slurries appropriate for SSC. Nanoparticle induced nucleation catalysis was also examined in a common aluminum alloy, A356, using the DET. All nanoparticles catalyzed nucleation of the primary Al phase. However, undercoolings varied depending on the nanoparticle identity and average diameter. The variation in undercoolings generally agreed with a modified lattice disregistry theory and the free growth theory. For nanoparticles with a small lattice spacing mismatch with the Al phase, undercoolings approached the size dependent free growth limit. Binary alloys of magnesium and zinc showed significant strength and ductility enhancements with the addition of 1.5 weight % SiC nanoparticles. Transmission electron microscope (TEM) study of the nanocomposite showed the MgZn2 phase among the nanoparticles and a reduction of the Mg 7Zn3 and Mg2Zn3 phases that were common in the monolithic samples. Thermal analysis supported this observed phase selection. The demonstrated nucleation catalysis and phase selection resulted in processing and property enhancement in the MMNCs.

  19. Karstic Phenomena Susceptibility Map of MÉXICO

    NASA Astrophysics Data System (ADS)

    Espinasa-Pereña, R.

    2013-05-01

    Approximately 20% of the territory of México is underlain by karstifiable rocks, mostly limestones and in lesser proportions gypsum. The majority of these rocks are distributed along the eastern and southern Sierra Madre, the state of Chiapas and the Yucatán peninsula. Differences in geological structure, climate and geomorphic history have resulted in a great variety of karstic landscapes and types of forms. Several important population centers, including large cities with several million inhabitants and numerous smaller towns are built on karstic terrains and obtain their water supplies from karstic aquifers and/or dispose of their waste products on this type of terrain. Severe problems of waste disposal and aquifer contamination have occurred. Additionally, numerous instances of catastrophic collapse and formation of karstic sinkholes have been registered in the Mexican territory, which have affected many communities, roads and other infrastructure, and have even cost several lives. Lack of knowledge of the special characteristics of karstic terrains and their distribution has compounded these problems. As a first approach to these issues, the existing map of Mexican karst (Espinasa-Pereña, 2007) was modified according to the geotechnical classification proposed by Waltham & Fookes (2003). An important consideration taken into account is the difference in speed of development of karstic features depending on lithology, which makes karst developed in gypsum much more hazardous than limestone karst, and also the degree of soil coverage and the types of sinkholes developed on the cover. Also taken in consideration are the differences between karst developed in the Sierra Madre, with rocks highly deformed and fractured, and karst developed on the Yucatán peninsula with almost negligible deformation of the rocks. The resulting map will be useful to Civil Protection authorities as a tool in prognosticating possible affectations due to karstic phenomena. References: ESPINASA-PEREÑA, R., 2007, "El Karst de México", Mapa NA III 3, in Coll-Hurtado, A., Coord., "Nuevo Atlas Nacional de México", Instituto de Geografía, Universidad Nacional Autónoma de México. WALTHAM, A.C. and FOOKES, P.G., 2003, Engineering classification of karst ground conditions, Quarterly Journal of Engineering Geology and Hydrology, Vol. 36, pp. 101-118.

  20. Domain specific phenomena at ferroelectric perovskite surfaces

    NASA Astrophysics Data System (ADS)

    Li, Dongbo

    Ferroelectric compounds are the basis of traditional electronic ceramic devices. The ferroelectric response is being explored as components in emerging nanoscale devices. At these length scales, the fundamental aspects of atomic structure and reactions at ferroelectric surfaces are critical to a range of device applications. In this dissertation, Scanning Probe Microscopy was employed to study the domain specific phenomena at ferroelectric perovskite surfaces. The primary aim of these studies is to acquire a detailed understanding of polarization related processes at ferroelectric surfaces and to generate new insights into basic mechanisms behind them. Using a combination of scanning tunneling microscopy (STM), non-contact atomic force microscopy (nc-AFM), and low energy electron diffraction (LEED), surface structure and stability of BaTiO3 (001) was investigated. It is discovered that this surface adopts a family of reconstructions, each depending on thermo-chemical history. Surface reconstruction evolution with temperature and chemical potential of environments was understood through density function theoretical (DFT) calculations that predict the surface diagram with thermodynamically most favorable surface phases under varying conditions. Theoretical calculations were done by A. Kolpak and A. Rappe. Comparisons of the results from the calculations with the STM and nc-AFM observations were used to construct atomic models for the reconstructed surfaces. The relationship between atomic domain polarization and local surface interactions was studied with two approaches. Using piezoforce microscopy (PFM) and scanning surface potential microscopy (SSPM), the interaction between electron injection and ferroelectric lattice was investigated. The observed polarization reorientation through surface charging was further explored to control domain structure at the nano-meter scale. The effect of electron beam dosage, current, and voltage was quantified for PZT thin films. By coupling the capability of scanning probes and/or electron beams to control the domain polarization at the nanometer scale to the specificity of photochemical reactions on ferroelectric domains, nanostructures with magnetic properties were assembled at ferroelectric surfaces. Using SSPM, the effect of polarization orientation on CO2 adsorption was examined and quantified, leading to the discovery of a sticking coefficient difference by a factor of 4 for opposite domains in both BaTiO 3 and lead zirconate titanate (PZT) crystals. The differences were discussed in terms of the possible adsorption mechanisms at surfaces. The molecular adsorption mechanism was deduced with reference to temperature programmed desorption (TPD) measurements from M. He and J. Vohs and DFT calculations from A. Kolpak and A. Rappe.

  1. The structure and energy balance of cool star atmospheres

    NASA Technical Reports Server (NTRS)

    Linsky, J. L.

    1982-01-01

    The atmospheric structure and energy balance phenomena associated with magnetic fields in the Sun are reviewed and it is shown that similar phenomena occur in cool stars. The evidence for the weakening or disappearance of transition regions and coronae is discussed together with the appearance of extended cool chromospheres with large mass loss, near V-R = 0.80 in the H-R diagram. Like the solar atmosphere, these atmospheres are not homogeneous and there is considerable evidence for plage regions with bright TR emission lines that overlie dark (presumably magnetic) star spots. The IUE observations are providing important information on the energy balance in these atmospheres that should guide theoretical calculations of the nonradiative heating rate. Recent high dispersion spectra are providing unique information concerning which components of close binary systems are the dominant contributors to the observed emission. A recent unanticipated discovery is that the transition lines are redshifted (an antiwind) in DRa (G2 Ib) and perhaps other stars. Finally, the G and K giants and supergiants are classified into three groups depending on whether their atmospheres are dominated by closed magnetic flux tubes, open field geometries, or a predominately open geometry with a few closed flux tubes embedded.

  2. The Mars atmosphere as seen from Curiosity

    NASA Astrophysics Data System (ADS)

    Mischna, Michael

    Study of the Mars atmosphere by the Mars Science Laboratory (MSL) has been ongoing since immediately after landing on August 6, 2012 (UTC) at the bottom of Gale Crater. The MSL Rover Environmental Monitoring Station (REMS) has been the primary payload for atmospheric monitoring, while additional observations from the ChemCam, Mastcam, Navcam and Sample Analysis at Mars (SAM) instruments have augmented our understanding of the local martian environment at Gale. The REMS instrument consists of six separate sensor types, observing air and ground temperature, near-surface winds, relative humidity, surface pressure and UV radiation. The standard cadence of REMS observations consists of five-minute observations of 1 Hz frequency at the top of each hour, augmented by several one-hour “extended blocks” each sol, also at 1 Hz frequency, together yielding one of the most richly diverse and detailed samplings of the martian atmosphere. Among the intriguing atmospheric phenomena observed during the first 359 sols of the mission is a substantially greater (˜12% of the diurnal mean) diurnal pressure cycle than found in previous surface measurements by Viking at a similar season (˜3-4%), likely due to the topography of the crater environment. Measurements of air and ground temperature by REMS are seen to reflect both changes in atmospheric opacity as well as transitions in the surface geology (and surface thermal properties) along the rover’s traverse. The REMS UV sensor has provided the first measurements of ultraviolet flux at the martian surface, and identified dust events that reduce solar insolation at the surface. The REMS RH sensor has observed a seasonal change in humidity in addition to the expected diurnal variations in relative humidity; however, no surface frost has been detected through the first 360 sols of the mission. With a weekly cadence, Navcam images the local zenith for purposes of tracking cloud motion and wind direction, and likewise observes the horizon to search (thus far unsuccessfully) for visible dust devil activity. The Mastcam operates with a similar observing frequency for quantifying atmospheric opacity, while ChemCam is used in its ‘passive’ mode, while pointed at the sky, to measure atmospheric water vapor abundance. Lastly, the SAM suite has provided information about atmospheric composition, including trace species abundances and isotopic ratios, which may be used to infer the history and evolution of the martian atmosphere.

  3. Lithosphere-Atmosphere coupling: Spectral element modeling of the evolution of acoustic waves in the atmosphere from an underground source.

    NASA Astrophysics Data System (ADS)

    Averbuch, Gil; Price, Colin

    2015-04-01

    Lithosphere-Atmosphere coupling: Spectral element modeling of the evolution of acoustic waves in the atmosphere from an underground source. G. Averbuch, C. Price Department of Geosciences, Tel Aviv University, Israel Infrasound is one of the four Comprehensive Nuclear-Test Ban Treaty technologies for monitoring nuclear explosions. This technology measures the acoustic waves generated by the explosions followed by their propagation through the atmosphere. There are also natural phenomena that can act as an infrasound sources like sprites, volcanic eruptions and earthquakes. The infrasound waves generated from theses phenomena can also be detected by the infrasound arrays. In order to study the behavior of these waves, i.e. the physics of wave propagation in the atmosphere, their evolution and their trajectories, numerical methods are required. This presentation will deal with the evolution of acoustic waves generated by underground sources (earthquakes and underground explosions). A 2D Spectral elements formulation for lithosphere-atmosphere coupling will be presented. The formulation includes the elastic wave equation for the seismic waves and the momentum, mass and state equations for the acoustic waves in a moving stratified atmosphere. The coupling of the two media is made by boundary conditions that ensures the continuity of traction and velocity (displacement) in the normal component to the interface. This work has several objectives. The first is to study the evolution of acoustic waves in the atmosphere from an underground source. The second is to derive transmission coefficients for the energy flux with respect to the seismic magnitude and earth density. The third will be the generation of seismic waves from acoustic waves in the atmosphere. Is it possible?

  4. Realistic generation of natural phenomena based on video synthesis

    NASA Astrophysics Data System (ADS)

    Wang, Changbo; Quan, Hongyan; Li, Chenhui; Xiao, Zhao; Chen, Xiao; Li, Peng; Shen, Liuwei

    2009-10-01

    Research on the generation of natural phenomena has many applications in special effects of movie, battlefield simulation and virtual reality, etc. Based on video synthesis technique, a new approach is proposed for the synthesis of natural phenomena, including flowing water and fire flame. From the fire and flow video, the seamless video of arbitrary length is generated. Then, the interaction between wind and fire flame is achieved through the skeleton of flame. Later, the flow is also synthesized by extending the video textures using an edge resample method. Finally, we can integrate the synthesized natural phenomena into a virtual scene.

  5. Seepage phenomena on Mars at subzero temperature

    NASA Astrophysics Data System (ADS)

    Kereszturi, Akos; Möhlmann, Diedrich; Berczi, Szaniszlo; Ganti, Tibor; Horvath, Andras; Kuti, Adrienn; Pocs, Tamas; Sik, Andras; Szathmary, Eors

    At the southern hemisphere of Mars seasonal slope structures emanating from Dark Dune Spots are visible on MGS MOC, and MRO HiRISE images. Based on their analysis two groups of streaks could be identified: diffuse and fan shaped ones forming in an earlier phase of local spring, probably by CO2 gas jets, and confined streaks forming only on steep slopes during a later seasonal phase. The dark color of the streaks may arise from the dark color of the dune grains where surface frost disappeared above them, or caused by the phase change of the water ice to liquid-like water, or even it may be influenced by the solutes of salts in the undercooled interfacial water The second group's morphology (meandering style, ponds at their end), morphometry, and related theoretical modelling suggest they may form by undercooled water that remains in liquid phase in a thin layer around solid grains. We analyzed sequence of images, temperature and topographic data of Russel (54S 12E), Richardson (72S 180E) and an unnamed crater (68S 2E) during southern spring. The dark streaks here show slow motion, with an average speed of meter/day, when the maximal daytime temperature is between 190 and 220 K. Based on thermophysical considerations a thin layer of interfacial water is inevitable on mineral surfaces under the present conditions of Mars. With 10 precipitable micrometer of atmospheric water vapor, liquid phase can be present down about 190 K. Under such conditions dark streaks may form by the movement of grains lubricatred by interfacial water. This possibility have various consequences on chemical, mechanical or even possible astrobiological processes on Mars. Acknowledgment: This work was supported by the ESA ECS-project No. 98004 and the Pro Renovanda Cultura Hungariae Foundation.

  6. Measurement of the Atmospheric $\

    E-print Network

    Aartsen, M G; Abdou, Y; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Andeen, K; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Baum, V; Bay, R; Beattie, K; Beatty, J J; Bechet, S; Tjus, J Becker; Becker, K -H; Bell, M; Benabderrahmane, M L; BenZvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bertrand, D; Besson, D Z; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohaichuk, S; Bohm, C; Bose1, D; Boser, S; Botner, O; Brayeur, L; Brown, A M; Bruijn, R; Brunner, J; Buitink, S; Carson, M; Casey, J; Casier, M; Chirkin, D; Christy, B; Clark, K; Clevermann, F; Cohen, S; Cowen, D F; Silva, A H Cruz; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; De Ridder, S; Descamps, F; Desiati, P; de Vries-Uiterweerd, G; DeYoung, T; Diaz-Velez, J C; Dreyer, J; Dumm, J P; Dunkman, M; Eagan, R; Eberhardt, B; Eisch, J; Ellsworth, R W; Engdegard, O; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Franckowiak, A; Franke, R; Frantzen, K; Fuchs, T; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glusenkamp, T; Goldschmidt, A; Golup, G; Goodman, J A; Gora, D; Grant, D; Gross, A; Grullon, S; Gurtner, M; Ha, C; Ismail, A Haj; Hallgren, A; Halzen, F; Hanson, K; Heereman, D; Heimann, P; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huelsnitz, W; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Japaridze, G S; Jlelati, O; Kappes, A; Karg, T; Karle, A; Kiryluk, J; Kislat, F; Klas, J; Klein, S R; Kohne, J -H; Kohnen, G; Kolanoski, H; Kopke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krasberg, M; Kroll, G; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Landsman, H; Larson, M J; Lauer, R; Lesiak-Bzdak, M; Lunemann, J; Madsen, J; Maruyama, R; Mase, K; Matis, H S; McNally, F; Meagher, K; Merck, M; Meszaros, P; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Panknin, S; Paul, L; Pepper, J A; Heros, C Perez de los; Pieloth, D; Pirk, N; Posselt, J; Price, P B; Przybylski, G T; Radel, L; Rawlins, K; Redl, P; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Riedel, B; Rodrigues, J P; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Salameh, T; Sander, H -G; Santander, M; Sarkar, S; Schatto, K; Scheel, M; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schoneberg, S; Schonherr, L; Schonwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Seo, S H; Sestayo, Y; Seunarine, S; Sheremata, C; Smith, M W E; Soiron, M; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stasik, A; Stezelberger, T; Stokstad, R G; Stoss, A; Strahler, E A; Strom, R; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Ter-Antonyan, S; Tilav, S; Toale, P A; Toscano, S; Usner, M; van der Drift, D; van Eijndhoven, N; Van Overloop, A; van Santen, J; Vehring, M; Voge1, M; Vraeghe, M; Walck, C; Waldenmaier, T; Wallraff, M; Walter, M; Wasserman, R; Weaver, Ch; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, C; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zierke, S; Zilles, A; Zoll, M

    2012-01-01

    We report the first observation in a high energy neutrino telescope of cascades induced by atmospheric electron neutrinos and by neutral current interactions of atmospheric neutrinos of all flavors. Using data recorded during the first year of operation of IceCube's DeepCore low energy extension, a sample of 1029 events is observed in 281 days of data. The number of observed cascades is $N_{\\rm cascade} = 496 \\pm 66 (stat.) \\pm 88(syst.)$ and the rest of the sample consists of residual backgrounds due to atmospheric muons and charged current interactions of atmospheric muon neutrinos. The flux of the atmospheric electron neutrinos is determined in the energy range between approximately 80 GeV and 6 TeV and is consistent with models of atmospheric neutrinos.

  7. Fair weather atmospheric electricity

    NASA Astrophysics Data System (ADS)

    Harrison, R. G.

    2011-06-01

    Not long after Franklin's iconic studies, an atmospheric electric field was discovered in "fair weather" regions, well away from thunderstorms. The origin of the fair weather field was sought by Lord Kelvin, through development of electrostatic instrumentation and early data logging techniques, but was ultimately explained through the global circuit model of C.T.R. Wilson. In Wilson's model, charge exchanged by disturbed weather electrifies the ionosphere, and returns via a small vertical current density in fair weather regions. New insights into the relevance of fair weather atmospheric electricity to terrestrial and planetary atmospheres are now emerging. For example, there is a possible role of the global circuit current density in atmospheric processes, such as cloud formation. Beyond natural atmospheric processes, a novel practical application is the use of early atmospheric electrostatic investigations to provide quantitative information on past urban air pollution.

  8. Pluto's atmosphere near perihelion

    SciTech Connect

    Trafton, L.M. (Univ. of Texas, Austin (USA))

    1989-11-01

    A recent stellar occultation has confirmed predictions that Pluto has an atmosphere which is sufficiently thick to uniformly envelope the planet and to extend far above the surface. Pluto's atmosphere consists of methane and perhaps other volatile gases at temperatures below their freezing points; it should regulate the surface temperature of its volatile ices to a globally uniform value. As Pluto approaches and passes through perihelion, a seasonal maximum in the atmospheric bulk and a corresponding minimum in the exposed volatile ice abundance is expected to occur. The lag in maximum atmospheric bulk relative to perihelion will be diagnostic of the surface thermal properties. An estimate of Pluto's atmospheric bulk may result if a global darkening (resulting from the disappearance of the seasonally deposited frosts) occurs before the time of maximum atmospheric bulk. The ice deposited shortly after perihelion may be diagnostic of the composition of Pluto's volatile reservoir.

  9. Highly Evolved Exoplanet Atmospheres

    NASA Astrophysics Data System (ADS)

    Hu, Renyu

    2015-01-01

    It has been found that sub-Neptune-sized planets, although not existing in our Solar System, are ubiquitous in our interstellar neighborhood. This revelation is profound because, due to their special sizes and proximity to their host stars, Neptune- and sub-Neptune-sized exoplanets may have highly-evolved atmospheres. I will discuss helium-dominated atmospheres as one of the outcomes of extensive atmospheric evolution on warm Neptune- and sub-Neptune-sized exoplanets. The spectral characteristics, and the formation conditions of the helium atmosphere, as applied to GJ 436 b, will be discussed. As the observations to obtain the spectra of these planets continue to flourish, we will have the opportunity to study unconventional atmospheric chemical processes and test atmosphere evolution theories.

  10. Global Atmospheric Aerosol Modeling

    NASA Technical Reports Server (NTRS)

    Hendricks, Johannes; Aquila, Valentina; Righi, Mattia

    2012-01-01

    Global aerosol models are used to study the distribution and properties of atmospheric aerosol particles as well as their effects on clouds, atmospheric chemistry, radiation, and climate. The present article provides an overview of the basic concepts of global atmospheric aerosol modeling and shows some examples from a global aerosol simulation. Particular emphasis is placed on the simulation of aerosol particles and their effects within global climate models.

  11. Oscillations in stellar atmospheres

    NASA Technical Reports Server (NTRS)

    Costa, A.; Ringuelet, A. E.; Fontenla, J. M.

    1989-01-01

    Atmospheric excitation and propagation of oscillations are analyzed for typical pulsating stars. The linear, plane-parallel approach for the pulsating atmosphere gives a local description of the phenomenon. From the local analysis of oscillations, the minimum frequencies are obtained for radially propagating waves. The comparison of the minimum frequencies obtained for a variety of stellar types is in good agreement with the observed periods of the oscillations. The role of the atmosphere in the globar stellar pulsations is thus emphasized.

  12. Relativistic breakdown in planetary atmospheres

    SciTech Connect

    Dwyer, J. R. [Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, Florida 32901 (United States)

    2007-04-15

    In 2003, a new electrical breakdown mechanism involving the production of runaway avalanches by positive feedback from runaway positrons and energetic photons was introduced. This mechanism, which shall be referred to as 'relativistic feedback', allows runaway discharges in gases to become self-sustaining, dramatically increasing the flux of runaway electrons, the accompanying high-energy radiation, and resulting ionization. Using detailed Monte Carlo calculations, properties of relativistic feedback are investigated. It is found that once relativistic feedback fully commences, electrical breakdown will occur and the ambient electric field, extending over cubic kilometers, will be discharged in as little as 2x10{sup -5} s. Furthermore, it is found that the flux of energetic electrons and x rays generated by this mechanism can exceed the flux generated by the standard relativistic runaway electron model by a factor of 10{sup 13}, making relativistic feedback a good candidate for explaining terrestrial gamma-ray flashes and other high-energy phenomena observed in the Earth's atmosphere.

  13. Probing Cytological and Reproductive Phenomena by Means of Bryophytes.

    ERIC Educational Resources Information Center

    Newton, M. E.

    1985-01-01

    Describes procedures (recommended for both secondary and college levels) to study mitosis, Giemsa C-banding, reproductive phenomena (including alternation of generations), and phototropism in mosses and liverworts. (JN)

  14. Non-equilibrium fluctuation induced-phenomena in quantum electrodynamics

    E-print Network

    Golyk, Vladyslav Alexander

    2014-01-01

    We study fluctuation-induced phenomena in systems out of thermal equilibrium, resulting from the stochastic nature of quantum and thermal fluctuations of electromagnetic currents and waves. Specifically, we study radiative ...

  15. Infrared thermometry study of nanofluid pool boiling phenomena

    E-print Network

    Gerardi, Craig

    Abstract Infrared thermometry was used to obtain first-of-a-kind, time- and space-resolved data for pool boiling phenomena in water-based nanofluids with diamond and silica nanoparticles at low concentration (<0.1 vol.%). ...

  16. Novel applications of Maxwell's equations to quantum and thermal phenomena

    E-print Network

    McCauley, Alexander P. (Alexander Patrick)

    2011-01-01

    This thesis is concerned with the extension of Maxwell's equations to situations far removed from standard electromagnetism, in order to discover novel phenomena. We discuss our contributions to the efforts to describe ...

  17. INVESTIGATIONS INTO BIOFOULING PHENOMENA IN FINE PORE AERATION DEVICES

    EPA Science Inventory

    Microbiologically-based procedures were used to describe biofouling phenomena on fine pore aeration devices and to determine whether biofilm characteristics could be related to diffuser process performance parameters. Fine pore diffusers were obtained from five municipal wastewa...

  18. INVESTIGATION INTO BIOFOULING PHENOMENA IN FINE PORE AERATION DEVICES

    EPA Science Inventory

    Microbiologically-based procedures were used to describe biofouling phenomena on fine pore aeration devices and to determine whether biofilm characteristics could be related to diffuser process performance parameters. ine pore diffusers were obtained from five municipal wastewate...

  19. Mathematical Modeling of Natural Phenomena: A Fuzzy Logic Approach

    E-print Network

    Margaliot, Michael

    Mathematical Modeling of Natural Phenomena: A Fuzzy Logic Approach Michael Margaliot School: Linguistic modeling, animal and human behavior, territorial be- havior, mathematical modeling in biology using mathematical tools. Fuzzy logic theory provides the most suitable tool for transforming verbal

  20. Simulation and design optimization for linear wave phenomena on metamaterials

    E-print Network

    Saà-Seoane, Joel

    2011-01-01

    Periodicity can change materials properties in a very unintuitive way. Many wave propagation phenomena, such as waveguides, light bending structures or frequency filters can be modeled through finite periodic structures ...

  1. Justifying Beliefs About Seance Phenomena in 19th Century Britain 

    E-print Network

    Stubbs, Harriet

    2012-11-28

    This study aims to discover how people in 19th century Britain justified their beliefs about séance phenomena, with a view to understanding how expressions of belief about the paranormal are constructed. Paranormal beliefs have been studied...

  2. High speed imaging of transient non-Newtonian fluid phenomena

    E-print Network

    Gallup, Benjamin H. (Benjamin Hodsdon), 1982-

    2004-01-01

    In this thesis, I investigate the utility of high speed imaging for gaining scientific insight into the nature of short-duration transient fluid phenomena, specifically applied to the Kaye effect. The Kaye effect, noted ...

  3. Distributed Parameter Estimation for Monitoring Diffusion Phenomena Using Physical Models

    E-print Network

    Krishnamachari, Bhaskar

    of relevant phenomena include the temperature field in an ecosystem, clouds of gases in the air, polluting. In this contest people study the optimal way (in the sense of least energy consumption) to transfer node

  4. emergent phenomena in flat worlds Kai P. Schmidt

    E-print Network

    Kierfeld, Jan

    phenomena high-temperature superconductivity Geim/Novoselov, nobel price (2010) Kane/Mele, Science (2006-temperature superconductivity Geim/Novoselov, nobel price (2010) Kane/Mele, Science (2006) Bernevig/Hughes/Zhang, Science (2006

  5. Modular Representations of Cognitive Phenomena in AI, Psychology and Neuroscience

    E-print Network

    Bryson, Joanna J.

    Modular Representations of Cognitive Phenomena in AI, Psychology and Neuroscience Joanna J. Bryson of cognitive science -- psychology, arti- ficial intelligence and neuroscience. This framework starts from and across the cognitive science disciplines: artificial intelligence (AI), psychology and neuroscience

  6. The Lattice-Boltzmann Method for Simulating Gaseous Phenomena

    E-print Network

    Mueller, Klaus

    animation. We introduce the Lattice Boltzmann Model (LBM), which simulates the microscopic movement of fluid phenomena, such as rolling clouds, moving dust, rising steam, and billowing smoke, play an important role

  7. Water in the Atmosphere

    NSDL National Science Digital Library

    In this activity, participants learn about the atmosphere by making observations and taking measurements. They will go outside and use scientific equipment to collect atmospheric moisture data (temperature, relative humidity, precipitation and cloud cover). Students will use this qualitative and quantitative data to understand how water is found in the atmosphere, how the atmosphere determines weather and climate, and how Earth’s spheres are connected through the water cycle. The data collection is based on protocols from the GLOBE program. This activity uses the 5E instructional model and is part of the "Survivor Earth" series of one-hour lessons.

  8. Assessing psychologists' knowledge and attitudes toward near-death phenomena

    Microsoft Academic Search

    Barbara A. Walker; Robert D. Russell

    1989-01-01

    Nina Thornburg's (1988) Near-Death Phenomena Knowledge and Attitudes Questionnaire was distributed to 326 randomly selected Illinois psychologists. Of 117 usable questionnaires received, the mean score for knowledge questions was 7.5 of a maximum score of 18. Respondents were most knowledgeable about near-death elements of peace, out-of-body transcendence, and tunnel\\/light phenomena. The mean score for the attitude portion of the instrument

  9. Selected Aspects of Flow Phenomena in Heavy Ion Collisions

    SciTech Connect

    Petrovici, Mihai; Pop, Amalia [National Institute for Physics and Nuclear Engineering, Bucharest (Romania)

    2008-01-24

    Dynamical aspects of heavy ion collisions play an essential role in the attempt to produce and study in the laboratory states of matter supposed to exist in different phases of the Universe evolution. Flow phenomena evidenced in heavy ion interactions, caused by the gradients produced during the collision, opened the possibility to access information on in-medium effects, matter equation of state and possible phase transitions. Selected aspects of flow phenomena in heavy ion collisions will be presented.

  10. Classification of Transient Phenomena in Distribution System using wavelet Transform

    NASA Astrophysics Data System (ADS)

    Sedighi, Alireza

    2014-05-01

    An efficient procedure for classification of transient phenomena in distribution systems is proposed in this paper. The proposed method has been applied to classify some transient phenomena such as inrush current, load switching, capacitor switching and single phase to ground fault. The new scheme is based on wavelet transform algorithm. All of the events for feature extraction and test are simulated using Electro Magnetic Transient Program (EMTP). Results show high accuracy of proposed method.

  11. Atomic and nuclear interference phenomena and their applications

    E-print Network

    Kuznetsova, Yelena Anatolyevna

    2005-08-29

    ATOMIC AND NUCLEAR INTERFERENCE AND COHERENCE PHENOMENA AND THEIR APPLICATIONS A Dissertation by YELENA ANATOLYEVNA KUZNETSOVA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of DOCTOR OF PHILOSOPHY May 2005 Major Subject: Physics ATOMIC AND NUCLEAR INTERFERENCE PHENOMENA AND THEIR APPLICATIONS A Dissertation by YELENA ANATOLYEVNA KUZNETSOVA Submitted to Texas A&M University in partial fulfillment of the requirements...

  12. Department of Energy Natural Phenomena Hazards Mitigation Program

    SciTech Connect

    Murray, R.C.

    1993-09-01

    This paper will present a summary of past and present accomplishments of the Natural Phenomena Hazards Program that has been ongoing at Lawrence Livermore National Laboratory since 1975. The Natural Phenomena covered includes earthquake; winds, hurricanes, and tornadoes; flooding and precipitation; lightning; and volcanic events. The work is organized into four major areas (1) Policy, requirements, standards, and guidance (2) Technical support, research development, (3) Technology transfer, and (4) Oversight.

  13. Geochemical cycles of atmospheric gases

    NASA Technical Reports Server (NTRS)

    Walker, J. C. G.; Drever, J. I.

    1988-01-01

    The processes that control the atmosphere and atmospheric changes are reviewed. The geochemical cycles of water vapor, nitrogen, carbon dioxide, oxygen, and minor atmospheric constituents are examined. Changes in atmospheric chemistry with time are discussed using evidence from the rock record and analysis of the present atmosphere. The role of biological evolution in the history of the atmosphere and projected changes in the future atmosphere are considered.

  14. Light flash phenomena induced by HzE particles

    NASA Technical Reports Server (NTRS)

    Mcnulty, P. J.; Pease, V. P.

    1980-01-01

    Astronauts and Apollo and Skylab missions have reported observing a variety of visual phenomena when their eyes are closed and adapted to darkness. These phenomena have been collectively labelled as light flashes. Visual phenomena which are similar in appearance to those observed in space have been demonstrated at the number of accelerator facilities by expressing the eyes of human subjects to beams of various types of radiation. In some laboratory experiments Cerenkov radiation was found to be the basis for the flashes observed while in other experiments Cerenkov radiation could apparently be ruled out. Experiments that differentiate between Cerenkov radiation and other possible mechanisms for inducing visual phenomena was then compared. The phenomena obtained in the presence and absence of Cerenkov radiation were designed and conducted. A new mechanism proposed to explain the visual phenomena observed by Skylab astronauts as they passed through the South Atlantic Anomaly, namely nuclear interactions in and near the sensitive layer of the retina, is covered. Also some studies to search for similar transient effects of space radiation on sensors and microcomputer memories are described.

  15. Simulation of atmospheric temperature effects on cosmic ray muon flux

    NASA Astrophysics Data System (ADS)

    Tognini, Stefano Castro; Gomes, Ricardo Avelino

    2015-05-01

    The collision between a cosmic ray and an atmosphere nucleus produces a set of secondary particles, which will decay or interact with other atmosphere elements. This set of events produced a primary particle is known as an extensive air shower (EAS) and is composed by a muonic, a hadronic and an electromagnetic component. The muonic flux, produced mainly by pions and kaons decays, has a dependency with the atmosphere's effective temperature: an increase in the effective temperature results in a lower density profile, which decreases the probability of pions and kaons to interact with the atmosphere and, consequently, resulting in a major number of meson decays. Such correlation between the muon flux and the atmosphere's effective temperature was measured by a set of experiments, such as AMANDA, Borexino, MACRO and MINOS. This phenomena can be investigated by simulating the final muon flux produced by two different parameterizations of the isothermal atmospheric model in CORSIKA, where each parameterization is described by a depth function which can be related to the muon flux in the same way that the muon flux is related to the temperature. This research checks the agreement among different high energy hadronic interactions models and the physical expected behavior of the atmosphere temperature effect by analyzing a set of variables, such as the height of the primary interaction and the difference in the muon flux.

  16. Global survey of upper atmospheric transient luminous events on the ROCSAT-2 satellite

    Microsoft Academic Search

    J. L. Chern; R. R. Hsu; H. T. Sua; S. B. Mende; H. Fukunishi; Y. Takahashi; L. C. Lee

    2003-01-01

    Upper atmospheric transient luminous events (TLEs; sprite, elves, blue jet, etc.) are recently discovered thunderstorm-induced phenomena. Imager of sprites\\/upper atmospheric lightning (ISUAL) is a scientific payload on the Taiwan's ROCSAT-2 satellite that aims primarily to provide crucial observation data on these TLEs from space. The ISUAL payload includes an intensified CCD imager, a six-channel spectrophotometer, and two array photometers. All

  17. Origin and evolution of planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Lewis, John S.

    1992-01-01

    This report concerns several research tasks related to the origin and evolution of planetary atmospheres and the large-scale distribution of volatile elements in the Solar System. These tasks and their present status are as follows: (1) we have conducted an analysis of the volatility and condensation behavior of compounds of iron, aluminum, and phosphorus in the atmosphere of Venus in response to publish interpretations of the Soviet Venera probe XRF experiment data, to investigate the chemistry of volcanic gases, injection of volatiles by cometary and asteroidal impactors, and reactions in the troposphere; (2) we have completed and are now writing up our research on condensation-accretion modeling of the terrestrial planets; (3) we have laid the groundwork for a detailed study of the effects of water transport in the solar nebula on the bulk composition, oxidation state, and volatile content of preplanetary solids; (4) we have completed an extensive laboratory study of cryovolcanic materials in the outer solar system; (5) we have begun to study the impact erosion and shock alteration of the atmosphere of Mars resulting from cometary and asteroidal bombardment; and (6) we have developed a new Monte Carlo model of the cometary and asteroidal bombardment flux on the terrestrial planets, including all relevant chemical and physical processes associated with atmospheric entry and impact, to assess both the hazards posed by this bombardment to life on Earth and the degree of cross-correlation between the various phenomena (NO(x) production, explosive yield, crater production, iridium signature, etc.) that characterize this bombardment. The purpose of these investigations has been to contribute to the developing understanding of both the dynamics of long-term planetary atmosphere evolution and the short-term stability of planetary surface environments.

  18. Spent nuclear fuel project detonation phenomena of hydrogen/oxygen in spent fuel containers

    SciTech Connect

    Cooper, T.D.

    1996-09-30

    Movement of Spent N Reactor fuels from the Hanford K Basins near the Columbia River to Dry interim storage facility on the Hanford plateau will require repackaging the fuel in the basins into multi-canister overpacks (MCOs), drying of the fuel, transporting the contained fuel, hot conditioning, and finally interim storage. Each of these functions will be accomplished while the fuel is contained in the MCOs by several mechanisms. The principal source of hydrogenand oxygen within the MCOs is residual water from the vacuum drying and hot conditioning operations. This document assesses the detonation phenomena of hydrogen and oxygen in the spent fuel containers. Several process scenarios have been identified that could generate detonation pressures that exceed the nominal 10 atmosphere design limit ofthe MCOS. Only 42 grams of radiolized water are required to establish this condition.

  19. Seasonal-scale Observational Data Analysis and Atmospheric Phenomenology for the Cold Land Processes Experiment

    NASA Technical Reports Server (NTRS)

    Poulos, Gregory S.; Stamus, Peter A.; Snook, John S.

    2005-01-01

    The Cold Land Processes Experiment (CLPX) experiment emphasized the development of a strong synergism between process-oriented understanding, land surface models and microwave remote sensing. Our work sought to investigate which topographically- generated atmospheric phenomena are most relevant to the CLPX MSA's for the purpose of evaluating their climatic importance to net local moisture fluxes and snow transport through the use of high-resolution data assimilation/atmospheric numerical modeling techniques. Our task was to create three long-term, scientific quality atmospheric datasets for quantitative analysis (for all CLPX researchers) and provide a summary of the meteorologically-relevant phenomena of the three MSAs (see Figure) over northern Colorado. Our efforts required the ingest of a variety of CLPX datasets and the execution an atmospheric and land surface data assimilation system based on the Navier-Stokes equations (the Local Analysis and Prediction System, LAPS, and an atmospheric numerical weather prediction model, as required) at topographically- relevant grid spacing (approx. 500 m). The resulting dataset will be analyzed by the CLPX community as a part of their larger research goals to determine the relative influence of various atmospheric phenomena on processes relevant to CLPX scientific goals.

  20. Characteristics of aerosol at a lower atmospheric layer in DRAGON field campaign

    NASA Astrophysics Data System (ADS)

    KUJI, M.; Azuma, Y.; Kitakoga, S.; Sano, I.; Holben, B. N.

    2013-12-01

    Air pollution arises severely over East Asia with the rapid economic development nowadays. Monitoring the atmospheric environment, as one of the purposes, an intensive field campaign, Distributed Regional Aerosol Gridded Observation Networks (DRAGON), was carried out in the spring of year 2012, led by National Aeronautics and Space Administration (NASA). At that time, atmospheric phenomena such as Yellow sand and haze events were observed at Nara in the western part of Japan, as one of the DRAGON observation sites. The atmospheric events were characterized with the AErosol RObotic NETwork (AERONET) data. As a result of the data analysis, it was found that more light-absorbing and smaller particles dominated at the lower than upper atmospheric layer for the Kosa event in particular. A backward trajectory analysis suggested that the Yellow sand event traveled over the East Asian industrial cities, which could lead to a mixture of sand and air pollutants with moderate particle size and light-absorptivity. In addition, visibility observation was evaluated quantitatively with AERONET data in the DRAGON campaign since eye observation was inherently semi-quantitative. The extinction coefficient estimated from visibility was compared to that from AERONET. As a result, it was found that the extinction coefficients were generally consistent to each other. But there were some discrepancies, which could be caused with the atmospheric phenomena or aerosol types. It is confirmed that visibility is strongly influenced with aerosols in the case of severe atmospheric phenomena in particular.

  1. Ground-based Optical Observations of Geophysical Phenomena: Aurora Borealis and Meteors

    NASA Astrophysics Data System (ADS)

    Samara, Marilia

    2010-10-01

    Advances in low-light level imaging technology have enabled significant improvements in the ground based study of geophysical phenomena. In this talk we focus on two such phenomena that occur in the Earth's ionosphere: aurorae and meteors. Imaging the aurora which is created by the interplay of the Earth's magnetosphere, ionosphere and atmosphere, provides a tool for remote sensing physical processes that are otherwise very difficult to study. By quantifying the intensities, scale sizes and lifetimes of auroral structures, we can gain significant insight into the physics behind the generation of the aurora and the interaction of the magnetosphere with the solar wind. Additionally, the combination of imaging with radars provides complimentary data and therefore more information than either method on its own. Meteor observations are a perfect example of this because the radar can accurately determine only the line-of-sight component of velocity, while imaging provides the direction of motion, the perpendicular velocity and brightness (a proxy for mass), therefore enabling a much more accurate determination of the full velocity vector and mass.

  2. Characterization of Microwave-Induced Electric Discharge Phenomena in Metal–Solvent Mixtures

    PubMed Central

    Chen, Wen; Gutmann, Bernhard; Kappe, C Oliver

    2012-01-01

    Electric discharge phenomena in metal–solvent mixtures are investigated utilizing a high field density, sealed-vessel, single-mode 2.45 GHz microwave reactor with a built-in camera. Particular emphasis is placed on studying the discharges exhibited by different metals (Mg, Zn, Cu, Fe, Ni) of varying particle sizes and morphologies in organic solvents (e.g., benzene) at different electric field strengths. Discharge phenomena for diamagnetic and paramagnetic metals (Mg, Zn, Cu) depend strongly on the size of the used particles. With small particles, short-lived corona discharges are observed that do not lead to a complete breakdown. Under high microwave power conditions or with large particles, however, bright sparks and arcs are experienced, often accompanied by solvent decomposition and formation of considerable amounts of graphitized material. Small ferromagnetic Fe and Ni powders (<40 ?m) are heated very rapidly in benzene suspensions and start to glow in the microwave field, whereas larger particles exhibit extremely strong discharges. Electric discharges were also observed when Cu metal or other conductive materials such as silicon carbide were exposed to the microwave field in the absence of a solvent in an argon or nitrogen atmosphere. PMID:24551491

  3. Oceanography and Atmospheric Sciences

    E-print Network

    Oceanography and Atmospheric Sciences 1959­2009 WayneBurt. #12;Oceanography and Atmospheric in Oceanography (TENOC). Wayne Burt immediately responds with proposal to President Strand of Oregon State College to start a graduate Department of Oceanography. 1959 Oregon State Board of Higher Education approves

  4. Atmospheric illumination and shadows

    Microsoft Academic Search

    Nelson L. Max

    1986-01-01

    The shadow volume algorithm of Frank Crow was reorganized to provide information on the regions of illuminated space in front of each visible surface. This information is used to calculate the extra intensity due to atmospheric scattering, so when the atmosphere is partly in shadow, columns of scattered light will be visible. For efficiency in sorting the shadow edges, the

  5. Introduction to Circulating Atmospheres

    Microsoft Academic Search

    I. N. James

    1995-01-01

    This book gives an account of the modern view of the global circulation of the atmosphere. It accounts for the observed nature of the circulation and theories and simple models of the mechanisms that drive it. Early chapters concentrate on the classical view of the global circulation, on the processes that generate atmospheric motions, and on the dynamical constraints that

  6. MODIS Atmospheric Data Handler

    NASA Technical Reports Server (NTRS)

    Anantharaj, Valentine; Fitzpatrick, Patrick

    2008-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) Atmosphere Data Handler software converts the HDF data to ASCII format, and outputs: (1) atmospheric profiles of temperature and dew point and (2) total precipitable water. Quality-control data are also considered in the export procedure.

  7. Upper Atmosphere Dynamics

    Microsoft Academic Search

    M. P. Friedman

    1970-01-01

    We are able to construct three-dimensional global models of the upper atmosphere (120 to 800 km) by solving the conservation equations of mass, momentum, and energy. We show that variation of conditions at the lower boundary, 120 km, affects the atmosphere only to about 200-km altitude. Differing results obtained by in situ satellite or rocket measurements in the 120- to

  8. Clouds in Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    West, R.

    1999-01-01

    In the terrestrial atmosphere clouds are familiar as vast collections of small water drops or ice cyrstals suspended in the air. The study of clouds touches on many facets of armospheric science. The chemistry of clouds is tied to the chemistry of the surrounding atmosphere.

  9. Atmospheric Welcome and

    E-print Network

    Collett Jr., Jeffrey L.

    1 Atmospheric Chemistry 3 4 2 MAIN PARKING FOOD TENT 5 6 28 9 2 12 2 Welcome and Information Check. Atmospheric Chemistry Mobile Laboratory Come to parking area in back of building to tour our truck outfitted-on science experiments for kids of all ages Food Tent and Seating ATS WEST LOWER PARKING LOT Complimentary

  10. Atmosphere Composition Model

    NSDL National Science Digital Library

    Lori Lambertson

    2007-01-01

    In this activity, learners create a model using metric measuring tapes and atmosphere composition data. Learners will investigate the major components of the atmosphere (nitrogen and oxygen) as well as the minor components which raise questions about global warming and greenhouse gases.

  11. Photochemistry of planetary atmospheres. [Mars atmospheric composition

    NASA Technical Reports Server (NTRS)

    Stief, L. J.

    1973-01-01

    The atmospheric composition of Mars is presented, and the applicability of laboratory data on CO2 absorption cross sections and quantum yields of dissociation is discussed. A summary and critical evaluation are presented on the various mechanisms proposed for converting the photodissociation products CO and O2 back to CO2.

  12. Update on atmospheric neutrinos

    SciTech Connect

    Gonzalez-Garcia, M.C.; Nunokawa, H.; Peres, O.L.; Valle, J.W. [Departament de Fisica Teorica, Instituto de Fisica Corpuscular---C.S.I.C., Universitat de Valencia 46100 Burjassot, Valencia (Spain)] [Departament de Fisica Teorica, Instituto de Fisica Corpuscular---C.S.I.C., Universitat de Valencia 46100 Burjassot, Valencia (Spain); Gonzalez-Garcia, M.C. [Instituto de Fisica Teorica, Universidade Estadual Paulista, Rua Pamplona 145, 01405-900 Sao Paulo (Brazil)] [Instituto de Fisica Teorica, Universidade Estadual Paulista, Rua Pamplona 145, 01405-900 Sao Paulo (Brazil); Stanev, T. [Bartol Research Institute, University of Delaware, Newark, Delaware 19716 (United States)] [Bartol Research Institute, University of Delaware, Newark, Delaware 19716 (United States)

    1998-08-01

    We discuss the impact of recent experimental results on the determination of atmospheric neutrino oscillation parameters. We use all published results on atmospheric neutrinos, including the preliminary large statistics data of Super-Kamiokande. We reanalyze the data in terms of both {nu}{sub {mu}}{r_arrow}{nu}{sub {tau}} and {nu}{sub {mu}}{r_arrow}{nu}{sub e} channels using new improved calculations of the atmospheric neutrino flux. We compare the sensitivity attained in atmospheric neutrino experiments with those of accelerator and reactor neutrino oscillation searches, including the recent CHOOZ experiment. We briefly comment on the implications of atmospheric neutrino data in relation to future searches for neutrino oscillations with long baselines, such as the K2K, MINOS, ICARUS, and NOE experiments. {copyright} {ital 1998} {ital The American Physical Society}

  13. Earth's early atmosphere.

    PubMed

    Kasting, J F

    1993-02-12

    Ideas about atmospheric composition and climate on the early Earth have evolved considerably over the last 30 years, but many uncertainties still remain. It is generally agreed that the atmosphere contained little or no free oxygen initially and that oxygen concentrations increased markedly near 2.0 billion years ago, but the precise timing of and reasons for its rise remain unexplained. Likewise, it is usually conceded that the atmospheric greenhouse effect must have been higher in the past to offset reduced solar luminosity, but the levels of atmospheric carbon dioxide and other greenhouse gases required remain speculative. A better understanding of past atmospheric evolution is important to understanding the evolution of life and to predicting whether Earth-like planets might exist elsewhere in the galaxy. PMID:11536547

  14. Atmospheric Mercury Deposition Monitoring ? National Atmospheric Deposition Program (NADP)

    EPA Science Inventory

    The National Atmospheric Deposition Program (NADP) developed and operates a collaborative network of atmospheric mercury monitoring sites based in North America ? the Atmospheric Mercury Network (AMNet). The justification for the network was growing interest and demand from many ...

  15. NASA's Upper Atmosphere Research Program (UARP) and Atmospheric Chemistry Modeling and Analysis Program (ACMAP): Research Summaries 1997-1999

    NASA Technical Reports Server (NTRS)

    Kurylo, M. J.; DeCola, P. L.; Kaye, J. A.

    2000-01-01

    Under the mandate contained in the FY 1976 NASA Authorization Act, the National Aeronautics and Space Administration (NASA) has developed and is implementing a comprehensive program of research, technology development, and monitoring of the Earth's upper atmosphere, with emphasis on the upper troposphere and stratosphere. This program aims at expanding our chemical and physical understanding to permit both the quantitative analysis of current perturbations as well as the assessment of possible future changes in this important region of our environment. It is carried out jointly by the Upper Atmosphere Research Program (UARP) and the Atmospheric Chemistry Modeling and Analysis Program (ACMAP), both managed within the Research Division in the Office of Earth Science at NASA. Significant contributions to this effort have also been provided by the Atmospheric Effects of Aviation Project (AEAP) of NASA's Office of Aero-Space Technology. The long-term objectives of the present program are to perform research to: understand the physics, chemistry, and transport processes of the upper troposphere and the stratosphere and their control on the distribution of atmospheric chemical species such as ozone; assess possible perturbations to the composition of the atmosphere caused by human activities and natural phenomena (with a specific emphasis on trace gas geographical distributions, sources, and sinks and the role of trace gases in defining the chemical composition of the upper atmosphere); understand the processes affecting the distributions of radiatively active species in the atmosphere, and the importance of chemical-radiative-dynamical feedbacks on the meteorology and climatology of the stratosphere and troposphere; and understand ozone production, loss, and recovery in an atmosphere with increasing abundances of greenhouse gases. The current report is composed of two parts. Part 1 summarizes the objectives, status, and accomplishments of the research tasks supported under NASA UARP and ACMAP in a document entitled, Research Summaries 1997- 1999. Part 2 is entitled Present State of Knowledge of the Upper Atmosphere 1999 An Assessment Report.

  16. Atmospheric Environment 39 (2005) 45754582 Conjugate mass transfer during gas absorption by falling liquid

    E-print Network

    Elperin, Tov

    2005-01-01

    occurring phenomena and industrial processes involving sprays, e.g. atmospheric physics, wet deposition. Gas the wet acid deposition in the environment. Oxides of nitrogen (NOx) such as nitric oxide and nitrogen dioxide, and carbon dioxide (CO2) may be generated by different types of combustors, e.g., boilers

  17. On Atmospheric Refraction and its Bearing on the Transmission of Electromagnetic Waves Round the Earth's Surface

    Microsoft Academic Search

    J A Fleming

    1913-01-01

    In this Paper the author considers the conditions under which true atmospheric refraction would be sufficient to carry a ray of light or electromagnetic radiation sent out horizontally from any point on the earth's surface round the earth parallel to its surface. It is now generally agreed that pure diffraction is insufficient to account for all the phenomena of long-distance

  18. Internal Waves in the Atmosphere from High-Resolution Radar Measurements

    Microsoft Academic Search

    E. E. Gossard; J. H. Richter; D. Atlas

    1970-01-01

    A radar sounding system developed by Richter has a height resolution (about I meter) capable of resolving the detailed structure of small features in the atmosphere that were never before seen. Two distinctly different types of wave phenomena characterize many of the records. One type is a long-period internal wave. The mechanism of generation is discussed, and waves observed on

  19. The NetLander atmospheric instrument system (ATMIS): description and performance assessment

    Microsoft Academic Search

    J. Polkko; A.-M Harri; T. Siili; F. Angrilli; S. Calcutt; D. Crisp; S. Larsen; J.-P Pommereau; P. Stoppato; A. Lehto; C. Malique; J. E Tillman

    2000-01-01

    The pointwise meteorological observations of the Viking Lander and Mars Pathfinder as well as the orbital mapping and sounding performed by, e.g., Mariner 9, Viking Orbiters and the Mars Global Surveyor have given a good understanding of the basic behaviour of the Martian atmosphere. However, the more detailed characterisation of the Martian circulation patterns, boundary layer phenomena and climatological cycles

  20. Atmospheric and adaptive optics

    NASA Astrophysics Data System (ADS)

    Hickson, Paul

    2014-11-01

    Atmospheric optics is the study of optical effects induced by the atmosphere on light propagating from distant sources. Of particular concern to astronomers is atmospheric turbulence, which limits the performance of ground-based telescopes. The past two decades have seen remarkable growth in the capabilities and performance of adaptive optics (AO) systems. These opto-mechanical systems actively compensate for the blurring effect of the Earth's turbulent atmosphere. By sensing, and correcting, wavefront distortion introduced by atmospheric index-of-refraction variations, AO systems can produce images with resolution approaching the diffraction limit of the telescope at near-infrared wavelengths. This review highlights the physical processes and fundamental relations of atmospheric optics that are most relevant to astronomy, and discusses the techniques used to characterize atmospheric turbulence. The fundamentals of AO are then introduced and the many types of advanced AO systems that have been developed are described. The principles of each are outlined, and the performance and limitations are examined. Aspects of photometric and astrometric measurements of AO-corrected images are considered. The paper concludes with a discussion of some of the challenges related to current and future AO systems, particularly those that will equip the next generation of large, ground-based optical and infrared telescopes.

  1. The Puerto Rico Weather Camp 2012 is a summer experience hosted by the NOAA Center for Atmospheric Sciences at UPR Mayagez (UPRM) and co-sponsored by the

    E-print Network

    Gilbes, Fernando

    The Puerto Rico Weather Camp 2012 is a summer experience hosted by the NOAA Center for Atmospheric about diverse topics including the complex tropical weather and climate phenomena, the atmosphere observation, and many others. Participants also get to interact with scientists, National Weather Service

  2. The photochemistry of planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Dalgarno, A.

    1988-01-01

    Recent theoretical and observational investigations of photochemical processes in the atmospheres of the planets and their satellites are reviewed. Particular attention is given to the CO2-dominated atmospheres of Mars and Venus, the hydrogen-dominated atmospheres of the Jovian planets, the SO2 atmosphere of Io, and the massive atmospheres of Titan and Triton. The principal reaction paths involved are listed and briefly characterized, and numerical data on atmospheric compositions are given in tables.

  3. Introduction to Circulating Atmospheres

    NASA Astrophysics Data System (ADS)

    James, I. N.

    1995-10-01

    This book gives an account of the modern view of the global circulation of the atmosphere. It accounts for the observed nature of the circulation and theories and simple models of the mechanisms that drive it. Early chapters concentrate on the classical view of the global circulation, on the processes that generate atmospheric motions, and on the dynamical constraints that modify them. Later chapters develop more recent themes including low frequency variability and the circulation of other planetary atmospheres. Each chapter includes a set of problems.

  4. Atmospheric Visualization Collection (AVC)

    NSDL National Science Digital Library

    The AVC collection provides materials that facilitate research and learning about the atmosphere through visualization of atmospheric data. The collection provides access to an archive of data from the Atmospheric Radiation Measurement (ARM) program's Southern Great Plains (SGP), North Slope of Alaska (NSA), and Tropic West Pacific (TWP) sites. Educational material such as lesson plans and conceptual models based on these data are part of the collection. The data archive focuses on remote sensing related to the effects and interactions of sunlight, radiant energy, clouds, temperature, weather and climate. The collection website is translated into French, German, Japanese, Korean, Italian, Spanish, Chinese and Portuguese.

  5. Introduction to the Atmosphere

    NSDL National Science Digital Library

    This site provides a brief overview of the properties associated with the atmosphere, the thin envelope of air that surrounds our planet and is a mixture of gases, each with its own physical properties. It will help students to recognize that while ninety nine percent of the atmosphere is made up of nitrogen and oxygen, the rest is made up of trace gases that can have a large impact on atmospheric processes. The site serves as a reference for and includes links to seven classroom activities.

  6. Evolution of Atmospheres

    SciTech Connect

    Hanson, B.

    1993-02-12

    An atmosphere is the dynamic gaseous boundary layer between a planet and space. Many complex interactions affect the composition and time evolution of an atmosphere and control the environment - or climate - at a planet's surface. These include both reactions within the atmosphere as well as exchange of energy, gases, and dust with the planet below and the solar system above; for Earth today, interactions with the biosphere and oceans are paramount. In view of the large changes in inputs of energy and gases that have occurred since planets began to form and the complexity of the chemistry, it is not surprising that planetary climates have changed greatly and are continuing to change.

  7. Direct observation of thitherto unobservable quantum phenomena by using electrons

    PubMed Central

    Tonomura, Akira

    2005-01-01

    Fundamental aspects of quantum mechanics, which were discussed only theoretically as “thought experiments” in the 1920s and 1930s, have begun to frequently show up in nanoscopic regions owing to recent rapid progress in advanced technologies. Quantum phenomena were once regarded as the ultimate factors limiting further miniaturization trends of microstructured electronic devices, but now they have begun to be actively used as the principles for new devices such as quantum computers. To directly observe what had been unobservable quantum phenomena, we have tried to develop bright and monochromatic electron beams for the last 35 years. Every time the brightness of an electron beam improved, fundamental experiments in quantum mechanics became possible, and quantum phenomena became observable by using the wave nature of electrons. PMID:16150719

  8. Phenomena Identification and Ranking Technique (PIRT) Panel Meeting Summary Report

    SciTech Connect

    Mark Holbrook

    2007-07-01

    Phenomena Identification and Ranking Technique (PIRT) is a systematic way of gathering information from experts on a specific subject and ranking the importance of the information. NRC, in collaboration with DOE and the working group, conducted the PIRT exercises to identify safety-relevant phenomena for NGNP, and to assess and rank the importance and knowledge base for each phenomenon. The overall objective was to provide NRC with an expert assessment of the safety-relevant NGNP phenomena, and an overall assessment of R and D needs for NGNP licensing. The PIRT process was applied to five major topical areas relevant to NGNP safety and licensing: (1) thermofluids and accident analysis (including neutronics), (2) fission product transport, (3) high temperature materials, (4) graphite, and (5) process heat for hydrogen cogeneration.

  9. On the Physics of the Critical Ionization Velocity Phenomena

    NASA Astrophysics Data System (ADS)

    Papadopoulos, K.

    The interplay of collisional and collisionless phenomena in the interaction of a magnetoplasma streaming through neutral gas produces some of the most fascinating plasma physics phenomena. A key notion controlling such interactions is the existence of a "critical velocity" effect postulated in an ad hoc fashion by Alfvén, in his model of the formation of the solar system. Guided by recent laboratory and space experiments and plasma physics theory the author presents the basic plasma physics underlying the interaction. This is followed by a discussion of its relevance to the formation of the solar system and cometary tails, its controlling effect on plasma centrifuges and homopolar generators, and the fascinating possibility that critical velocity phenomena are controlling the space shuttle environment, transforming it into an artificial comet.

  10. Modeling and simulation of transport phenomena in ionic gels

    NASA Astrophysics Data System (ADS)

    Leichsenring, Peter; Wallmersperger, Thomas

    2015-04-01

    Ionic hydrogels belong to the class of polyelectrolyte gels or ionic gels. Their ability to swell or shrink under different environmental conditions such as change of pH, ion concentration or temperature make them promising materials, e.g. for microsensoric or microactuatoric devices. The hydrogel swelling exhibits nonlinear effects due to the occurrence of different interacting transport phenomena. Numerical simulations are an essential part in the ongoing development of microsensors and microactuators. In order to determine transport effects due to diffusion, migration and convection a multiphase mesoscale model based on the Theory of Porous Media is applied. The governing field equations are solved in the transient regime by applying the Finite Element Method. By means of the derived numerical framework a detailed investigation of the different transport phenomena is carried out. Numerical experiments are performed to characterize the dominating transfer phenomena for ionic gels under chemical stimulation.

  11. Pendulum Phenomena and the Assessment of Scientific Inquiry Capabilities

    NASA Astrophysics Data System (ADS)

    Zachos, Paul

    2004-11-01

    Phenomena associated with the pendulum present numerous opportunities for assessing higher order human capabilities related to scientific inquiry and the discovery of natural law. This paper illustrates how systematic assessment of scientific inquiry capabilities, using pendulum phenomena, can provide a useful tool for classroom teachers and program planners. Structured inquiry, a technique of teacher-facilitated student inquiry involving direct interaction between students and natural phenomena, is presented as a way to establish student competence in applying scientific inquiry capabilities (e.g., conceptualizing variation due to error). This approach to assessment can heighten student curiosity and provide a concrete referent for complementary cultural, historical, and scientific instruction. The role of assessment in constructively shaping science education programs is considered.

  12. Diffusion phenomena of cells and biomolecules in microfluidic devices.

    PubMed

    Yildiz-Ozturk, Ece; Yesil-Celiktas, Ozlem

    2015-09-01

    Biomicrofluidics is an emerging field at the cross roads of microfluidics and life sciences which requires intensive research efforts in terms of introducing appropriate designs, production techniques, and analysis. The ultimate goal is to deliver innovative and cost-effective microfluidic devices to biotech, biomedical, and pharmaceutical industries. Therefore, creating an in-depth understanding of the transport phenomena of cells and biomolecules becomes vital and concurrently poses significant challenges. The present article outlines the recent advancements in diffusion phenomena of cells and biomolecules by highlighting transport principles from an engineering perspective, cell responses in microfluidic devices with emphases on diffusion- and flow-based microfluidic gradient platforms, macroscopic and microscopic approaches for investigating the diffusion phenomena of biomolecules, microfluidic platforms for the delivery of these molecules, as well as the state of the art in biological applications of mammalian cell responses and diffusion of biomolecules. PMID:26180576

  13. Correlation between Space and Atmospheric March 2012 Extreme Events

    NASA Astrophysics Data System (ADS)

    Anagnostopoulos, Georgios C.

    2015-04-01

    Previous studies have provided statistical evidence of a solar cycle correlation between space weather and meteorological phenomena. In this study we present a case study, the March 2012 events, with a strong evidence of such a correlation between space and atmospheric extreme events. March 2012 phenomena, beside a great CME (March 7) and a following superstorm, has been most known in the scientific community as well as in the public from the historic heat wave in USA. This event was not anticipated by solely atmospheric models (called a "black swan event":http://www.esrl.noaa.gov/psd/csi/events/2012/marchheatwave/anticipation.html). Furthermore, various extreme phenomena as high temperatures, intense rainfalls and ice extent at middle and high latitudes followed the March 7, 2012 CME all over the globe (USA, Europe, Australia, Antartic), while unusual measurements of various atmospheric and ionospheric quantities were observed by a series of satellites (TIMED, MODIS, NOAA etc.) In this study we concentrate to (a) the unusual high maximum of temperature in north-east USA (highest values since 1910) and (b) intense winds, rainfalls and fluctuating (>1500 V/m) geolectric fields in South East Europe (Greece). These events were observed almost simultaneously with geomagnetic storms and unusual radiation belt electron precipitation (RBEP) events on days 6-9, 10-12 and 26-28.3.2012 (two CMEs and one CIR). The most striking result is the time coincidence of variations of several space and meteorological measurements, which, for instance, most probably suggests a direct influence of the RBEP on the intense rainfalls observed in Greece. It is also possible that the RBEP at polar latitudes was responsible for the positive North Atlantic Oscillation effect evaluated at those times, which contributed to the global middle and high latitude weather variations. Our study provides an example of possible space weather utility to the atmospheric models, and, therefore, to the everyday life worldwide.

  14. Research at the earth's edge. [tethered satellite study of upper atmosphere

    NASA Technical Reports Server (NTRS)

    Anderson, John L.; Wood, George M., Jr.; Siemers, Paul M.

    1988-01-01

    The Space Shuttle Orbiter-deployed Tethered Satellite System (TSS) could allow an Orbiter at a 200 km orbital altitude to reach down to atmospheric altitudes of 90 km, in order to study weather phenomena, pollutant transport, 'nuclear winter' smoke transport, atmospheric physics and dynamics, sun-earth interactions, ecosystem interactions, and radio communications. The TSS satellite, a 1.5-m diameter sphere, would carry scientific instrumentation which could initially be dedicated to the investigation of energy and momentum transfer between a tethered system and the upper atmosphere.

  15. Fundamental investigation of duct/ESP phenomena. Final report

    SciTech Connect

    Brown, C.A. [Radian Corp., Austin, TX (United States); Durham, M.D. [ADA Technologies, Inc., Englewood, CO (United States); Sowa, W.A. [California Univ., Irvine, CA (United States). Combustion Lab.; Himes, R.M. [Fossil Energy Research Corp., Laguna Hills, CA (United States); Mahaffey, W.A. [CHAM of North America, Inc., Huntsville, AL (United States)

    1991-10-21

    Radian Corporation was contracted to investigate duct injection and ESP phenomena in a 1.7 MW pilot plant constructed for this test program. This study was an attempt to resolve problems found in previous studies and answer remaining questions for the technology using an approach which concentrates on the fundamental mechanisms of the process. The goal of the study was to obtain a better understanding of the basic physical and chemical phenomena that control: (1) the desulfurization of flue gas by calcium-based reagent, and (2) the coupling of an existing ESP particulate collection device to the duct injection process. Process economics are being studied by others. (VC)

  16. Thermal atmospheric models

    NASA Technical Reports Server (NTRS)

    Johnson, Hollis Ralph

    1987-01-01

    The static thermal atmosphere is described and its predictions are compared to observations both to test the validity of the classic assumptions and to distinguish and describe those spectral features with diagnostic value.

  17. TRACE ATMOSPHERIC CONSTITUENTS

    E-print Network

    Schwartz, Stephen E.

    . Peterson 3. Catalytic Autoxidation of Aqueous Sulfur Dioxide in Relationship to Atmospheric Systems Michael. Zak 8. Turbulent Transport of Ozone to Surfaces Common in the Eastern Half of the United States 345

  18. Planetary Science (mostly atmospheres)

    E-print Network

    Withers, Paul

    Planetary Science (mostly atmospheres) at Boston University Paul Withers withers@bu.edu Planetary Science Decadal Survey Town Hall Meeting Boston University 2011.03.26 #12;Selected people Supriya John

  19. CSIRO Atmospheric Research

    NSDL National Science Digital Library

    The homepage for CSIRO Atmospheric Research, which is devoted "to conduct world-class research into the atmospheric environment and provide advice and applications for the benefit of Australia." Visitors have access to many reports written by the staff on topics such as Climate Modeling and Applications and Air Quality Modeling and Dispersion. Scientists interested in remote sensing can download CalWatch: Calibration Status of the NOAA AVHRR Solar Reflectance Channels: CalWatch Revison 1, a report that discusses results of research dealing with the operational calibration of the AVHRR data sets. Using JAVA, users can download Weatherwall, which demonstrates how to incorporate technologies of real-time data gathering and data management. Students can read about ozone depletion and El Nino events. All can check out the atmospheric forecasts for Victoria and Melbourne. With lots of information and many reports available; researchers, students, and those interested in Australia's atmosphere should check out this valuable site.

  20. ATMOSPHERIC SCIENCE MEETS NANOSCIENCE

    E-print Network

    Schwartz, Stephen E.

    : Natural: Dust, sea salt, haze (Great Smokies, Blue Ridge Mtns.) Anthropogenic: Smoke, smog Importance 1600 1800 2000 Law Dome Adelie Land Siple South Pole Mauna Loa Hawaii ATMOSPHERIC CARBON DIOXIDE

  1. Atmospheric optical calibration system

    DOEpatents

    Hulstrom, Roland L. (Bloomfield, CO); Cannon, Theodore W. (Golden, CO)

    1988-01-01

    An atmospheric optical calibration system is provided to compare actual atmospheric optical conditions to standard atmospheric optical conditions on the basis of aerosol optical depth, relative air mass, and diffuse horizontal skylight to global horizontal photon flux ratio. An indicator can show the extent to which the actual conditions vary from standard conditions. Aerosol scattering and absorption properties, diffuse horizontal skylight to global horizontal photon flux ratio, and precipitable water vapor determined on a real-time basis for optical and pressure measurements are also used to generate a computer spectral model and for correcting actual performance response of a photovoltaic device to standard atmospheric optical condition response on a real-time basis as the device is being tested in actual outdoor conditions.

  2. Experiments on atmospheric processes

    NASA Technical Reports Server (NTRS)

    Vaughan, W. W.

    1977-01-01

    Spacelab technology is examined as applied to the observation of the earth's weather patterns, composition, thermodynamics, and kinematics. An atmospheric cloud physics laboratory and a geophysical fluid flow cell are individually outlined as planned payload experiment efforts.

  3. Study of atmospheric dynamics

    NASA Technical Reports Server (NTRS)

    Mcnider, Richard T.; Christy, John R.; Cox, Gregory N.

    1993-01-01

    In order to better understand the dynamics of the global atmosphere, a data set of precision temperature measurements was developed using the NASA built Microwave Sounding Unit. Modeling research was carried out to validate global model outputs using various satellite data. Idealized flows in a rotating annulus were studied and applied to the general circulation of the atmosphere. Dynamic stratospheric ozone fluctuations were investigated. An extensive bibliography and several reprints are appended.

  4. Dynamics of Triton's atmosphere

    NASA Astrophysics Data System (ADS)

    Ingersoll, A. P.

    1990-03-01

    It is argued here that the facts about Triton's atmosphere discovered by the recent Voyager encounter can be explained if Triton, like Mars, has a global, well-structured atmosphere in equilibrium with surface frosts. The subliming frost cap produces a polar anticyclone at low altitudes, with northeastward winds of about 5 m/s within the Ekman boundary layer. The temperature contrast between the cold frost-covered pole and the warm unforested equator produces westward winds at high altitudes.

  5. Hypervelocity atmospheric flight: Real gas flow fields

    NASA Technical Reports Server (NTRS)

    Howe, John T.

    1990-01-01

    Flight in the atmosphere is examined from the viewpoint of including real gas phenomena in the flow field about a vehicle flying at hypervelocity. That is to say, the flow field is subject not only to compressible phenomena, but is dominated by energetic phenomena. There are several significant features of such a flow field. Spatially, its composition can vary by both chemical and elemental species. The equations which describe the flow field include equations of state and mass, species, elemental, and electric charge continuity; momentum; and energy equations. These are nonlinear, coupled, partial differential equations that were reduced to a relatively compact set of equations of a self-consistent manner (which allows mass addition at the surface at a rate comparable to the free-stream mass flux). The equations and their inputs allow for transport of these quantities relative to the mass-averaged behavior of the flow field. Thus transport of mass by chemical, thermal, pressure, and forced diffusion; transport of momentum by viscosity; and transport of energy by conduction, chemical considerations, viscosity, and radiative transfer are included. The last of these complicate the set of equations by making the energy equation a partial integrodifferential equation. Each phenomenon is considered and represented mathematically by one or more developments. The coefficients which pertain are both thermodynamically and chemically dependent. Solutions of the equations are presented and discussed in considerable detail, with emphasis on severe energetic flow fields. For hypervelocity flight in low-density environments where gaseous reactions proceed at finite rates, chemical nonequilibrium is considered and some illustrations are presented. Finally, flight where the flow field may be out of equilibrium, both chemically and thermodynamically, is presented briefly.

  6. Hypervelocity atmospheric flight: Real gas flow fields

    NASA Technical Reports Server (NTRS)

    Howe, John T.

    1989-01-01

    Flight in the atmosphere is examined from the viewpoint of including real gas phenomena in the flow field about a vehicle flying at hypervelocity. That is to say, the flow field is subject not only to compressible phenomena, but is dominated by energetic phenomena. There are several significant features of such a flow field. Spatially, its composition can vary by both chemical and elemental species. The equations which describe the flow field include equations of state and mass, species, elemental, and electric charge continuity; momentum; and energy equations. These are nonlinear, coupled, partial differential equations that have been reduced to a relatively compact set of equations in a self-consistent manner (which allows mass addition at the surface at a rate comparable to the free-stream mass flux). The equations and their inputs allow for transport of these quantities relative to the mass-average behavior of the flow field. Thus transport of mass by chemical, thermal, pressure, and forced diffusion; transport of momentum by viscosity; and transport of energy by conduction, chemical considerations, viscosity, and radiative transfer are included. The last of these complicate the set of equations by making the energy equations a partial integrodifferential equation. Each phenomenon is considered and represented mathematically by one or more developments. The coefficients which pertain are both thermodynamically and chemically dependent. Solutions of the equations are presented and discussed in considerable detail, with emphasis on severe energetic flow fields. Hypervelocity flight in low-density environments where gaseous reactions proceed at finite rates chemical nonequilibrium is considered, and some illustrations are presented. Finally, flight where the flow field may be out of equilibrium, both chemically and thermodynamically, is presented briefly.

  7. Utö Atmospheric and Marine Research Station - a new Baltic Sea ICOS-site for sea-atmosphere research

    NASA Astrophysics Data System (ADS)

    Laakso, Lauri; Laurila, Tuomas; Mäkelä, Timo; Hatakka, Juha; Purokoski, Tero; Hietala, Riikka; Roine, Tuomo; Jämsen, Pertti; Kielosto, Sami; Asmi, Eija; Lonka, Harry; Alenius, Pekka; Drebs, Achim; Seppälä, Jukka; Ylöstalo, Pasi; Tamminen, Timo

    2015-04-01

    Atmospheric research has developed a concept of focused, multidisciplinary, automated observation platforms with continuous high time resolution observations. This approach containing state-of-the-art equipment has enabled research on physical, chemical and biological processes and seasonal variability and showed up new, previously unknown phenomena. New technical and engineering solutions allowing, such approach is also state-of-the-art in marine research through projects like US Ocean Observatories Initiative (OOI), European Multidisciplinary Seafloor Observatory (EMSO), JERICO-NEXT and Japanese DONET. At the Baltic Sea, on Island of Utö (59° 46'50N, 21° 22'23E), Finnish Meteorological Institute has observed meteorology since 1881, marine parameters since 1900 and a diversity of atmospheric chemical and physical variables since 1980. Recent years the stations has also been upgraded with aerosol observations, and together with Finnish Environment Institute, on marine observations. The current and observations under construction at Utö Atmospheric and Marine Research Station (en.ilmatieteenlaitos.fi/uto. Marine observations: surface waves, ice-cover radar, temperature and salinity and oxygen at different depths, chlorophyll, cyanobacteria, underwater flows, turbidity, pCO2 and nutrients. Atmospheric observations: T, WS, WD, visibility, cloud height, boundary layer wind profiles and turbulence, weather and underwater camera, aerosol particle size distributions, aerosol light scattering and absorption, SO2, NOx, CO, O3, CO2, CH4, sea-atmosphere CO2- and heat fluxes. In our presentation, we present for the first time some 100 years of climate relevant atmospheric and marine observations from Utö.

  8. Detection of organized airflow in the atmospheric boundary layer and the free atmosphere using a 3D-scanning coherent Doppler lidar

    NASA Astrophysics Data System (ADS)

    Fujiyoshi, Y.; Yamashita, K.; Fujiwara, C.

    2009-07-01

    We will overview organized airflows, turbulent and laminar structures in the atmospheric boundary layer and the free atmosphere newly detected by a 3D-scanning coherent Doppler lidar system (3D-CDL). Study of clouds becomes important especially in recent years, since they play an essential role in global climate systems and the earth environment. The aerosol-cloud interaction is not enough to evaluate aerosol indirect effect. Air-motion is the key factor that connects aerosols and clouds especially in the atmospheric boundary layer. Using the 3D-CDL, we detected such various kinds of atmospheric phenomena as plume, streaks, invisible dust-devils, fog, fire-work, local front, downburst, wake of buildings, gravity waves, Kelvin-Helmholtz instability waves, sea-breeze fronts, fine-weather cumulus, low-level stratus, mid-level clouds, mammatus clouds and cirrus clouds etc. Some of these phenomena are firstly observed by the 3D-CDL. We simulated some phenomena by using a Large Eddy Simulation (LES) model and compared the simulated structures with those observed by the 3D-CDL.

  9. Charging and discharging phenomena in simulated space environment

    Microsoft Academic Search

    Masayuki HIKITA; Mengu CHO

    2000-01-01

    Large space platform needs to be operated at high voltage. When a solar array has a negative voltage more than 200 V with respect to the plasma, arcing occurs. Experiments are carried out in order to elucidate charging and discharging phenomena on a solar array in simulated space environment and find mitigation techniques against arcing. Arcing occurs at the triple

  10. Scaling astrophysical phenomena to high-energy-density laboratory experiments

    Microsoft Academic Search

    D. D. Ryutov; B. A. Remington

    2002-01-01

    The spatial and temporal scales of astrophysical phenomena are typically 10-20 orders of magnitude greater than those of laboratory experiments intended to simulate them. Accordingly, the issue of similarity between the astrophysical phenomenon and its laboratory counterpart becomes quite important. Note also that in astrophysics, one is often dealing with highly dynamical systems, where orders of magnitude variation of the

  11. PROGRESS AND PROBLEMS IN THE THEORY OF REGENERATIVE PHENOMENA

    E-print Network

    PROGRESS AND PROBLEMS IN THE THEORY OF REGENERATIVE PHENOMENA J.F.C. Kingman Abstract Regenerative in Chung's magisterial account [2] of Markov processes with a countable state space, and this was provided in [23] and [24]. For Chung the fundamental objects are the transition functions pij(t) = P {X(t) = j|X(0

  12. PROGRESS AND PROBLEMS IN THE THEORY OF REGENERATIVE PHENOMENA

    E-print Network

    PROGRESS AND PROBLEMS IN THE THEORY OF REGENERATIVE PHENOMENA J.F.C. Kingman Abstract Regenerative, but a major milestone was the publication in 1960 by K.L. Chung of a magisterial account [3] of the theory second edition [4] is also worth study.) For Chung the fundamental quantities are the transition

  13. Lab 7: Fourier analysis and synthesis Fourier series (periodic phenomena)

    E-print Network

    Glashausser, Charles

    Lab 7: Fourier analysis and synthesis · Fourier series (periodic phenomena) · Fourier transform A powerful analytic tool that has many applications.... #12;Applications of Fourier analysis Periodic t n t dt = #12;By Lucas V. Barbosa Fourier series (animation) #12;Fourier analysis and synthesis

  14. Many-body phenomena in QED-cavity arrays [Invited

    SciTech Connect

    Tomadin, A. [Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck (Austria); Fazio, Rosario [NEST, Scuola Normale Superiore and INFM-CNR, Piazza dei Cavalieri 7, I-56126 Pisa (Italy)

    2010-06-15

    Coupled quantum electrodynamics (QED) cavities have been recently proposed as new systems to simulate a variety of equilibrium and nonequilibrium many-body phenomena. We present a brief review of their main properties together with a survey of the latest developments of the field and some perspectives concerning their experimental realizations and possible new theoretical directions.

  15. New Phenomena in NC Field Theory and Emergent Spacetime Geometry

    NASA Astrophysics Data System (ADS)

    Ydri, Badis

    2010-10-01

    We give a brief review of two nonperturbative phenomena typical of noncommutative field theory which are known to lead to the perturbative instability known as the UV-IR mixing. The first phenomena concerns the emergence/evaporation of spacetime geometry in matrix models which describe perturbative noncommutative gauge theory on fuzzy backgrounds. In particular we show that the transition from a geometrical background to a matrix phase makes the description of noncommutative gauge theory in terms of fields via the Weyl map only valid below a critical value g*. The second phenomena concerns the appearance of a nonuniform ordered phase in noncommutative scalar ?4 field theory and the spontaneous symmetry breaking of translational/rotational invariance which happens even in two dimensions. We argue that this phenomena also originates in the underlying matrix degrees of freedom of the noncommutative field theory. Furthermore it is conjectured that in addition to the usual WF fixed point at ? = 0 there must exist a novel fixed point at ? = ? corresponding to the quartic hermitian matrix model.

  16. Wave stimulated phenomena in inductively coupled magnetized plasmas

    Microsoft Academic Search

    K. P. Shamrai; S. Shinohara; V. F. Virko; V. M. Slobodyan; Yu V. Virko; G. S. Kirichenko

    2005-01-01

    Linear and nonlinear wave phenomena and their influence on the discharge performance are considered in the helicon plasma (HP) and magnetized inductively coupled plasma (MICP). Magnetic field configuration is shown to result in strong variation in the efficiency of plasma production caused by alterations of the character of wave processes rather than by the particle confinement. Effects of magnetic configuration

  17. SENSORY THREADS: SONIFYING IMPERCEPTIBLE PHENOMENA IN Robin Fencott

    E-print Network

    Bryan-Kinns, Nick

    there are countless rhythms and processes which we cannot feel or sense. Sensory Threads is an interdiserplinary. In the Sensory Threads experience, participants wear mobile sensing tech- nology (see figure 1, with discussionSENSORY THREADS: SONIFYING IMPERCEPTIBLE PHENOMENA IN THE WILD Robin Fencott Interaction, Media

  18. Bacteria, Biofilms and Fluid Dynamics: Elementary Flows and Unexpected Phenomena

    E-print Network

    Fisher, Frank

    Bacteria, Biofilms and Fluid Dynamics: Elementary Flows and Unexpected Phenomena Wednesday February the migration of bacteria along surfaces when exposed to a shear flow. In particular, we identify an unusual response where flow produces a directed motion of twitching bacteria in the upstream direction. (ii) We

  19. Phenomena and mechanism of electrical tree in silicone rubber

    Microsoft Academic Search

    B. X. Du; Z. L. Ma; Y. Gao

    2009-01-01

    In this paper, room temperature vulcanized (RTV) silicone rubber (SiR) was employed as test sample to investigate the tree aging phenomena and mechanism of silicone rubber under commercial voltage. The structures and growth characteristics of electrical tree in SiR were observed by using a digital camera. A new parameter, the treeing proportion is introduced to describe the electrical tree propagation

  20. Transport Phenomena in the Human Nasal Cavity: A Computational Model

    Microsoft Academic Search

    S. Naftali; R. C. Schroter; R. J. Shiner; D. Elad

    1998-01-01

    Nasal inspiration is important for maintaining the internal milieu of the lung, since ambient air is conditioned to nearly alveolar conditions (body temperature and fully saturated with water vapor) on reaching the nasopharynx. We conducted a two-dimensional computational study of transport phenomena in model transverse cross sections of the nasal cavity of normal and diseased human noses for inspiration under

  1. Hydraulic Fractures: multiscale phenomena, asymptotic and numerical solutions

    E-print Network

    Peirce, Anthony

    Hydraulic Fractures: multiscale phenomena, asymptotic and numerical solutions SANUM Conference (UMN) Eduard Siebrits (SLB) #12;2 Outline · Examples of hydraulic fractures · Governing equations well stimulation Fracturing Fluid Proppant #12;5 Quarries #12;6 Magma flow Tarkastad #12;7 Model EQ 1

  2. Quantitative relation between caustic phenomena and holographic fringes

    Microsoft Academic Search

    Bingheng Xiong; Junchang Li; Zhengrong Wang; Zhaoyong Xu; Shunyun Chen; Runhai Yang; Jinming Zhao

    2004-01-01

    In a previous paper we have described that some dark shadow areas appeared among the interference fringes in real-time holographic interferometry and we pointed that the appearing of these dark shadow regions are the phenomena of caustic in Geometry Optics. These dark shadow region bears certain relation with the interference fringes. The quantitative relation between caustics and real-time holographic interferometry

  3. A Review of Anode Phenomena in Vacuum Arcs

    Microsoft Academic Search

    H. Craig Miller

    1985-01-01

    This paper discusses arc modes at the anode, anode temperature measurments, anode ions, transitions of the arc into various modes (principally the anode-spot mode), and theoretical explanations of anode phenomena. A vacuum arc can exhibit five anode discharge modes: 1) a low-current mode in which the anode is basically passive, acting only as a collector of particles emitted from the

  4. Electromagnetically and Thermally Driven Flow Phenomena in Electroslag Welding

    E-print Network

    Eagar, Thomas W.

    ) Electromagnetically and Thermally Driven Flow Phenomena in Electroslag Welding A. H. DILAWARI, J for the Electroslag Welding Process. In the formulation, allowance has been made {or both etee- tromagnetic and b in the use of electroslag welding (ESW), particularly for the construction of thick walled pressure vessels

  5. Fundamental phenomena of quantum mechanics explored with neutron interferometers

    E-print Network

    J. Klepp; S. Sponar; Y. Hasegawa

    2014-07-11

    Ongoing fascination with quantum mechanics keeps driving the development of the wide field of quantum-optics, including its neutron-optics branch. Application of neutron-optical methods and, especially, neutron interferometry and polarimetry has a long-standing tradition for experimental investigations of fundamental quantum phenomena. We give an overview of related experimental efforts made in recent years.

  6. The Effects of THC and Psilocybin on Paranormal Phenomena

    Microsoft Academic Search

    Dick J. Bierman

    Two experiments are reported dealing with the effect of psychoactive drugs on paranormal phenomena. In the first experiment 40 subjects did two Ganzfeld ESP sessions in which they tried to get impressions of a remote target. One session while being, and one session while not-being intoxicated by Marijuana intake. When asked to select the actual target from 4 possible targets,

  7. Mapped Chebyshev pseudospectral method to study multiple scale phenomena

    Microsoft Academic Search

    Adrian Alexandrescu; Jose R. Salgueiro; V ´ õctor; M. Perez-Garc

    In the framework of mapped pseudospectral methods, we use a polynomial-type mapping function in order to describe accurately the dynamics of systems developing small size structures. Using error criteria related to the spectral interpolation error, the polynomial-type mapping is compared against previously proposed mappings for the study of collapse and shock wave phenomena. As a physical application, we study the

  8. A molecular-scale view on rotary lip sealing phenomena

    Microsoft Academic Search

    F. Schulz; K. Wiehler; V. M. Wollesen; M. Voetter

    1999-01-01

    Rotary lip sealing is not described sufficiently by present modelling techniques. Characterizing the sealed fluid only as a viscous continuum has not yet led to a conclusive description of the well known sealing, lubricating and pumping phenomena. This paper presents a new hypothesis and offers a new and different view on rotary lip sealing assuming significant molecular interactions within the

  9. Spin waves and quantum collective phenomena in Boltzmann gases

    Microsoft Academic Search

    E P Bashkin

    1986-01-01

    The concept of the quantum gas is introduced and illustrated by numerous examples. The fundamentals of the theory of collective phenomena in quantum Maxwellian gases are surveyed in a simple and readily assimilated form, and possible experimental studies are outlined. Particular attention is devoted to weakly-damped spin waves. The spectrum of these waves is calculated and the magnetic susceptibility generalized.

  10. Analogies between Scaling in Turbulence, Field Theory and Critical Phenomena

    E-print Network

    Gregory Eyink; Nigel Goldenfeld

    1994-07-05

    We discuss two distinct analogies between turbulence and field theory. In one analogue, the field theory has an infrared attractive renormalization-group fixed point and corresponds to critical phenomena. In the other analogue, the field theory has an ultraviolet attractive fixed point, as in quantum chromodynamics.

  11. Roughness-Induced Critical Phenomena in a Turbulent Flow

    Microsoft Academic Search

    Nigel Goldenfeld

    2006-01-01

    I present empirical evidence that turbulent flows are closely analogous to critical phenomena, from a reanalysis of friction factor measurements in rough pipes. The data collapse found here corresponds to Widom scaling near critical points, and implies that a full understanding of turbulence requires explicit accounting for boundary roughness.

  12. Analogies between scaling in turbulence, field theory, and critical phenomena

    Microsoft Academic Search

    Gregory Eyink; Nigel Goldenfeld

    1994-01-01

    We discuss two distinct analogies between turbulence and field theory. In one analog, the field theory has an infrared attractive renormalization-group fixed point and corresponds to critical phenomena. In the other analog, the field theory has an ultraviolet attractive fixed point, as in quantum chromodynamics.

  13. Roughness-induced critical phenomena in a turbulent flow

    E-print Network

    Nigel Goldenfeld

    2005-11-15

    I present empirical evidence that turbulent flows are closely analogous to critical phenomena, from a reanalysis of friction factor measurements in rough pipes. The data collapse found here corresponds to Widom scaling near critical points, and implies that a full understanding of turbulence requires explicit accounting for boundary roughness.

  14. Effect of nonlinear optical phenomena on retinal damage

    Microsoft Academic Search

    Benjamin A. Rockwell; Paul K. Kennedy; Robert J. Thomas; William P. Roach; Mark E. Rogers

    1995-01-01

    Recent studies of retinal damage due to ultrashort laser pulses have shown interesting behavior. Laser thresholds for retinal damage from ultrashort (i.e. phenomena affect the characteristics of light impinging the retina and hence,

  15. SELF-PERCEPTION: AN ALTERNATIVE INTERPRETATION OF COGNITIVE DISSONANCE PHENOMENA

    Microsoft Academic Search

    DARYL J. BEM

    1967-01-01

    A THEORY OF SELF-PERCEPTION IS PROPOSED TO PROVIDE AN ALTERNATIVE INTERPRETATION FOR SEVERAL OF THE MAJOR PHENOMENA EMBRACED BY FESTINGER'S THEORY OF COGNITIVE DISSONANCE AND TO EXPLICATE SOME OF THE SECONDARY PATTERNS OF DATA THAT HAVE APPEARED IN DISSONANCE EXPERIMENTS. IT IS SUGGESTED THAT THE ATTITUDE STATEMENTS WHICH COMPRISE THE MAJOR DEPENDENT VARIABLES IN DISSONANCE EXPERIMENTS MAY BE REGARDED AS

  16. Nuclear phenomena in low-energy nuclear reaction research.

    PubMed

    Krivit, Steven B

    2013-09-01

    This is a comment on Storms E (2010) Status of Cold Fusion, Naturwissenschaften 97:861-881. This comment provides the following remarks to other nuclear phenomena observed in low-energy nuclear reactions aside from helium-4 make significant contributions to the overall energy balance; and normal hydrogen, not just heavy hydrogen, produces excess heat. PMID:23949247

  17. Computational analysis of temperature rise phenomena in electric induction motors

    E-print Network

    Melnik, Roderick

    Computational analysis of temperature rise phenomena in electric induction motors Ying Huai: Electric induction motor; Thermal model; Finite element analysis frequency 1. Introduction An electric of the motor under the given operating conditions. The thermal analysis of electric induction motors can

  18. Spectral and Impact Phenomena in the Faraday Dark Space

    Microsoft Academic Search

    K. G. Emeleus; O. S. Duffendack

    1935-01-01

    Observations on the spectra of the negative glow and Faraday dark space in pure helium and in helium containing a trace of nitrogen lead to the conclusion that in the negative glow the phenomena are due mainly to collisions of fast (primary) electrons with normal atoms while in the Faraday dark space impacts of the second kind between normal and

  19. Beyond a Dichotomic Approach, the Case of Colour Phenomena

    ERIC Educational Resources Information Center

    Viennot, L.; de Hosson, C.

    2012-01-01

    This research documents the aims and the impact of a teaching experiment concerning colour phenomena. This teaching experiment is designed in order to make students consider not only the spectral composition of light but also its intensity, and to consider the absorption of light by a pigment as relative, instead of as total or zero. Eight…

  20. The Effects of Globalization Phenomena on Educational Concepts

    ERIC Educational Resources Information Center

    Schrottner, Barbara Theresia

    2010-01-01

    It is becoming more and more apparent that globalization processes represent, theoretically as well as practically, a challenge for educational sciences and therefore, it must be addressed within the sphere of education. Accordingly, educational conceptions have to adapt to globalization phenomena and focus more on alternative and innovative…

  1. Developing Critical Thinking through the Study of Paranormal Phenomena.

    ERIC Educational Resources Information Center

    Wesp, Richard; Montgomery, Kathleen

    1998-01-01

    Argues that accounts of paranormal phenomena can serve as an ideal medium in which to encourage students to develop critical-thinking skills. Describes a cooperative-learning approach used to teach critical thinking in a course on paranormal events. Reports that critical-thinking skills increased and that the course received favorable student…

  2. Chapter 7. Renewal Phenomena Renewal is life reborn.

    E-print Network

    Chen, Kani

    51 Chapter 7. Renewal Phenomena Renewal is life reborn. 7.1. Definitions and basic concepts. 7. Then, N(t) : t 0, is a renewal process. A mathematical definition: N(t) = max{n : n i=0 Xi t, } where, ...} or continuous: [0, ). Obviously, the path of a renewal process is non-decreasing. The renewal literally means

  3. A model for transfer phenomena in structured populations

    E-print Network

    Hinow, Peter

    phenomena #12;Cancer treatment options surgery radiotherapy cytotoxic chemotherapy newer strategies: immune. The expression of P-gp has been documented in breast cancers, sarcomas, neuroblastomas, leukemias and others% of all cancers (in particular cancers of the blood and metastatic tumors). However, the appearance

  4. SYMBOL STATISTICS: A NEW TOOL FOR UNDERSTANDING MULTIPHASE FLOW PHENOMENA

    E-print Network

    Tennessee, University of

    . In the language of nonlinear dynamics, we use symbol statistics to identify characteristic un- stableSYMBOL STATISTICS: A NEW TOOL FOR UNDERSTANDING MULTIPHASE FLOW PHENOMENA C.S. Daw Oak Ridge symbolization as a tool for identifying tempo- ral patterns in complex measurement signals. We describe

  5. Binding Phenomena within a Reductionist Theory of Grammatical Dependencies

    ERIC Educational Resources Information Center

    Drummond, Alex

    2011-01-01

    This thesis investigates the implications of binding phenomena for the development of a reductionist theory of grammatical dependencies. The starting point is the analysis of binding and control in Hornstein (2001, 2009). A number of revisions are made to this framework in order to develop a simpler and empirically more successful account of…

  6. New Phenomena in NC Field Theory and Emergent Spacetime Geometry

    SciTech Connect

    Ydri, Badis [Institute of Physics BM Annaba University, BP 12-23000-Annaba (Algeria)

    2010-10-31

    We give a brief review of two nonperturbative phenomena typical of noncommutative field theory which are known to lead to the perturbative instability known as the UV-IR mixing. The first phenomena concerns the emergence/evaporation of spacetime geometry in matrix models which describe perturbative noncommutative gauge theory on fuzzy backgrounds. In particular we show that the transition from a geometrical background to a matrix phase makes the description of noncommutative gauge theory in terms of fields via the Weyl map only valid below a critical value g*. The second phenomena concerns the appearance of a nonuniform ordered phase in noncommutative scalar {phi}{sup 4} field theory and the spontaneous symmetry breaking of translational/rotational invariance which happens even in two dimensions. We argue that this phenomena also originates in the underlying matrix degrees of freedom of the noncommutative field theory. Furthermore it is conjectured that in addition to the usual WF fixed point at {theta} = 0 there must exist a novel fixed point at {theta} = {infinity} corresponding to the quartic hermitian matrix model.

  7. Natural phenomena risk assessment at Rocky Flats Plant

    Microsoft Academic Search

    Foppe

    1985-01-01

    A realistic approach is currently being used at the Rocky Flats Plant to assess the risks of natural phenomena events. The methodology addresses frequency of occurrence estimates, damage stress on the facility and vital equipment, material-at-risk, release fractions and source terms, leakpath, dispersion and dosimetric models, risk curves, and an uncertainty analysis. 28 refs.

  8. Free energy calculations: Applications to chemical and biochemical phenomena

    Microsoft Academic Search

    Peter. Kollman

    1993-01-01

    The author will review the applications of free energy calculations employing molecular dynamics or Monte Carlo methods to a variety of chemical and biochemical phenomena. The focus is on the applications of such calculations to molecular solvation, molecular association, macromolecular stability, and enzyme catalysis. The molecules discussed range from monovalent ions and small molecules to proteins and nucleic acids.

  9. Free energy calculations: Applications to chemical and biochemical phenomena

    SciTech Connect

    Kollman, P. [Univ. of California, San Francisco, CA (United States). Dept. of Pharmaceutical Chemistry

    1993-11-01

    The author will review the applications of free energy calculations employing molecular dynamics or Monte Carlo methods to a variety of chemical and biochemical phenomena. The focus is on the applications of such calculations to molecular solvation, molecular association, macromolecular stability, and enzyme catalysis. The molecules discussed range from monovalent ions and small molecules to proteins and nucleic acids.

  10. Role of Agency in Causal Understanding of Natural Phenomena.

    ERIC Educational Resources Information Center

    Murayama, Isao

    1994-01-01

    Proposes causal field theory as a model of causal reasoning. Suggests that anomaly detection through comparison with natural events triggers causal reasoning. This anomaly is interpreted in terms of agency; therefore, natural phenomena can be understood through an appeal to agency. The mechanism proposed never changes with development, whereas…

  11. Eighty phenomena about the self: representation, evaluation, regulation, and change

    PubMed Central

    Thagard, Paul; Wood, Joanne V.

    2015-01-01

    We propose a new approach for examining self-related aspects and phenomena. The approach includes (1) a taxonomy and (2) an emphasis on multiple levels of mechanisms. The taxonomy categorizes approximately eighty self-related phenomena according to three primary functions involving the self: representing, effecting, and changing. The representing self encompasses the ways in which people depict themselves, either to themselves or to others (e.g., self-concepts, self-presentation). The effecting self concerns ways in which people facilitate or limit their own traits and behaviors (e.g., self-enhancement, self-regulation). The changing self is less time-limited than the effecting self; it concerns phenomena that involve lasting alterations in how people represent and control themselves (e.g., self-expansion, self-development). Each self-related phenomenon within these three categories may be examined at four levels of interacting mechanisms (social, individual, neural, and molecular). We illustrate our approach by focusing on seven self-related phenomena. PMID:25870574

  12. Torsional changes in surgery for A-V phenomena.

    PubMed

    Sharma, P; Halder, M; Prakash, P

    1997-03-01

    The role of torsion in the aetiopathogenesis of A-V phenomena has not been sufficiently emphasized. The success of vertical displacement of horizontal recti in correction of A or V has not been attributed to torsional changes. To evaluate this aspect, 21 cases of A or V phenomena were subjected to monocular recession-resection procedure with vertical shifting. Preoperative and postoperative torsional changes were evaluated on synoptophore (subjective torsion), and confirmed by fundus photography (objective torsion). Intorsion with A phenomenon was seen preoperatively in 5 of 8 cases which increased after surgery and was seen postoperatively in the other 3 cases also. Extorsion was observed in 5 of 13 cases pre operatively in 'V' phenomenon, but the changes in extorsion after surgery were less dramatic than those in intorsion. The oblique overactions were reduced in cases where they were present. Correction of A-V phenomena by torsion induced by vertical shifting of horizontal recti muscles is proposed, highlighting the role of torsion in A-V phenomena. PMID:9475009

  13. A Detailed Analysis of a Child's Conception of Physical Phenomena.

    ERIC Educational Resources Information Center

    Golshan, Mahtash Esfandiari

    Reported is a method of investigating thought processes of an 11-year-old girl concerning physical phenomena such as those underlying the operations of scientific apparatus--platform balance, the spring balance, the magnet, and the pendulum. It was discovered during a period of interviews that the subject's thought processes developed in such a…

  14. Europa's Atmosphere: Production & Loss

    NASA Astrophysics Data System (ADS)

    Bagenal, F.; Cassidy, T. A.; Dols, V.; Crary, F. J.

    2013-12-01

    Europa is embedded not only in the ionized material of the Io plasma torus, but is also surrounded by the material (both ionized and neutral) produced by the interaction of this plasma with the moon's surface and atmosphere. Moreover, there are energetic ions and electrons that diffuse inwards from the outer magnetosphere and interact with the moon and surrounding neutral clouds. The multiple components of Europa's environment are thought to vary on timescales of hours to weeks and to be strongly coupled. Europa's O2 atmosphere is created by ion bombardment of the surface. Earlier studies assumed that the energetic (10s keV) ions were responsible (see review in Smyth and Marconi, 2006). New research (Cassidy et al. 2013) suggests that the 'thermal' ion population of the Io plasma torus produces most of Europa's O2. But this cooler population is easily diverted by currents induced in Europa's ionosphere and prevented from reaching the surface. This feedback has not been adequately explored. Modelers have historically focused on a single piece of the puzzle; plasma modelers assume a static atmosphere and atmosphere modelers assume static plasma. We are now in a position to consider these new sources of atmosphere and determine how the observed system comes about as well as quantify the timescales and causes of its evolution. This begs the question is Europa's atmosphere-magnetosphere interaction self-regulating? We are specifically interested in how the system responds to changes - for example, how does Europa's atmosphere change when the inflowing plasma flux increases or decreases? What is the corresponding change in the electrodynamics and diversion of plasma flow around Europa? How much and on what time scale does the extended neutral cloud respond? And what are the consequences for the influx of energetic particles? We model this coupled system to address how each component responds to changes in the other components.

  15. Europa's Atmosphere: Production & Loss

    NASA Astrophysics Data System (ADS)

    Bagenal, Fran; Cassidy, T.; Dols, V.; Crary, F.

    2013-10-01

    Europa is embedded not only in the ionized material of the Io plasma torus, but is also surrounded by the material (both ionized and neutral) produced by the interaction of this plasma with the moon’s surface and atmosphere - as illustrated in the schematic below. Moreover, there are energetic ions and electrons that diffuse inwards from the outer magnetosphere and interact with the moon and surrounding neutral clouds. The multiple components of Europa’s environment are thought to vary on timescales of hours to weeks and to be strongly coupled. Europa’s O2 atmosphere is created by ion bombardment of the surface. Earlier studies assumed that the energetic (10s keV) ions were responsible (see review in Smyth and Marconi, 2006). New research (Cassidy et al. 2013) suggests that the “thermal” ion population of the Io plasma torus produces most of Europa’s O2. But this cooler population is easily diverted by currents induced in Europa’s ionosphere and prevented from reaching the surface. This feedback has not been adequately explored. Modelers have historically focused on a single piece of the puzzle; plasma modelers assume a static atmosphere and atmosphere modelers assume static plasma. We are now in a position to consider these new sources of atmosphere and determine how the observed system comes about as well as quantify the timescales and causes of its evolution. This begs the question is Europa’s atmosphere-magnetosphere interaction self-regulating? We are specifically interested in how the system responds to changes - for example, how does Europa’s atmosphere change when the inflowing plasma flux increases or decreases? What is the corresponding change in the electrodynamics and diversion of plasma flow around Europa? How much and on what time scale does the extended neutral cloud respond? And what are the consequences for the influx of energetic particles? We model this coupled system to address how each component responds to changes in the other components.

  16. Space Science I: Planetary Atmospheres

    E-print Network

    Johnson, Robert E.

    Space Science I: Planetary Atmospheres Atmospheric Structure and Transport Origins and Evolution of Planetary Atmospheres Books The New Solar System Chapters 8,9,11,13,15,17,18,20 #12;Space Science I, is crucial and is one goal of this course. #12;Space Science I: Planetary Atmospheres Goals To understand- 1

  17. Reference and Standard Atmosphere Models

    NASA Technical Reports Server (NTRS)

    Johnson, Dale L.; Roberts, Barry C.; Vaughan, William W.; Parker, Nelson C. (Technical Monitor)

    2002-01-01

    This paper describes the development of standard and reference atmosphere models along with the history of their origin and use since the mid 19th century. The first "Standard Atmospheres" were established by international agreement in the 1920's. Later some countries, notably the United States, also developed and published "Standard Atmospheres". The term "Reference Atmospheres" is used to identify atmosphere models for specific geographical locations. Range Reference Atmosphere Models developed first during the 1960's are examples of these descriptions of the atmosphere. This paper discusses the various models, scopes, applications and limitations relative to use in aerospace industry activities.

  18. Ultra-High Resolution Spectroscopic Remote Sensing: A Microscope on Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Kostiuk, Theodor

    2010-01-01

    Remote sensing of planetary atmospheres is not complete without studies of all levels of the atmosphere, including the dense cloudy- and haze filled troposphere, relatively clear and important stratosphere and the upper atmosphere, which are the first levels to experience the effects of solar radiation. High-resolution spectroscopy can provide valuable information on these regions of the atmosphere. Ultra-high spectral resolution studies can directly measure atmospheric winds, composition, temperature and non-thermal phenomena, which describe the physics and chemistry of the atmosphere. Spectroscopy in the middle to long infrared wavelengths can also probe levels where dust of haze limit measurements at shorter wavelength or can provide ambiguous results on atmospheric species abundances or winds. A spectroscopic technique in the middle infrared wavelengths analogous to a radio receiver. infrared heterodyne spectroscopy [1], will be describe and used to illustrate the detailed study of atmospheric phenomena not readily possible with other methods. The heterodyne spectral resolution with resolving power greater than 1,000.000 measures the true line shapes of emission and absorption lines in planetary atmospheres. The information on the region of line formation is contained in the line shapes. The absolute frequency of the lines can be measured to I part in 100 ,000,000 and can be used to accurately measure the Doppler frequency shift of the lines, directly measuring the line-of-sight velocity of the gas to --Im/s precision (winds). The technical and analytical methods developed and used to measure and analyze infrared heterodyne measurements will be described. Examples of studies on Titan, Venus, Mars, Earth, and Jupiter will be presented. 'These include atmospheric dynamics on slowly rotating bodies (Titan [2] and Venus [3] and temperature, composition and chemistry on Mars 141, Venus and Earth. The discovery and studies of unique atmospheric phenomena will also be described, such as non-thermal and lasing phenomena on Mars and Venus, mid-infrared aurora on Jupiter [5], and results of small body impacts on Jupiter [6]. The heterodyne technique can also be applied for detailed study of the Earth's stratosphere and mesosphere by measuring trace constituent abundances and temporal and spatial variability as well as winds, which provide information of transport. All ground-based measurements will be described as complementary and supporting studies for on-going and future space missions [7] (Mars Express, Venus Express, Cassini Huygens, JUNO, ExoMars Trace Gas Orbiter, and the Europa Jupiter System Mission, an Earth Science Venture Class missions), Proposed instrument and technology development for a space flight infrared heterodyne spectrometer will be described.

  19. Polarimetric Studies of the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Gosain, Sanjay

    2007-06-01

    Solar magnetic fields play an important role in the variety of activity phenomena observed on the sun. They are present right from Sun's deep radiative interior up-to the heliopause. Their evolution, mainly due to photospheric dynamics and flux emergence, leads to activity phenomena like flares, filament eruptions, Coronal Mass Ejections (CMEs). These phenomena directly affect near-Earth space weather by the accompanying high-energy radiation and charged particles. In order to predict these events a detailed understanding of solar magnetic structures is required. Thus, task of measuring solar magnetic fields is of utmost importance in solar physics. However, the measurement of solar magnetic fields is very challenging task. The challenge comes mainly from the fact that the measurements need to be done remotely by sensing the polarization (due to Zeeman effect) of solar spectral lines. Also, the distortions in imaging due to atmospheric "seeing" leads to poor spatial resolution and effects polarization measurements . The focus of this thesis is on the measurement aspects of solar magnetic fields. A new instrument is developed for measuring the vector magnetic fields in the photosphere. The instrument is called Solar Vector Magnetograph (SVM). The key features of the instrument are (i) symmetric imaging optics with no oblique reflections, to minimize instrumental polarization, (ii) a tunable narrow-band imaging filter for scanning the spectral line, which is based on Fabry-Perot etalon, (iii) dual-beam polarization analyzer (Savart Plate), to minimize seeing induced spurious polarization signals, and (iv) a self-developed instrument control software for automated observations. Further, a data-reduction and analysis package with graphical user interface (GUI) is developed for interactive data reduction. The interpretation of observed polarization, i.e., Stokes profiles, in terms of magnetic field vector is done by fitting them with theoretical profiles under Milne-Eddington model atmosphere assumptions. The packages are developed for this purpose as well as for the analysis and visualization of vector magnetograms. Finally, a study of the effect of vector magnetic field parameters on the solar acoustic p-modes is carried out.

  20. Fundamentals of Atmospheric Radiation

    NASA Astrophysics Data System (ADS)

    Bohren, Craig F.; Clothiaux, Eugene E.

    2006-02-01

    This textbook fills a gap in the literature for teaching material suitable for students of atmospheric science and courses on atmospheric radiation. It covers the fundamentals of emission, absorption, and scattering of electromagnetic radiation from ultraviolet to infrared and beyond. Much of the book applies to planetary atmosphere. The authors are physicists and teach at the largest meteorology department of the US at Penn State. Craig T. Bohren has taught the atmospheric radiation course there for the past 20 years with no book. Eugene Clothiaux has taken over and added to the course notes. Problems given in the text come from students, colleagues, and correspondents. The design of the figures especially for this book is meant to ease comprehension. Discussions have a graded approach with a thorough treatment of subjects, such as single scattering by particles, at different levels of complexity. The discussion of the multiple scattering theory begins with piles of plates. This simple theory introduces concepts in more advanced theories, i.e. optical thickness, single-scattering albedo, asymmetry parameter. The more complicated theory, the two-stream theory, then takes the reader beyond the pile-of-plates theory. Ideal for advanced undergraduate and graduate students of atmospheric science.

  1. LIMITS ON QUAOAR'S ATMOSPHERE

    SciTech Connect

    Fraser, Wesley C.; Gwyn, Stephen; Kavelaars, J. J. [Herzberg Institute of Astrophysics, 5071 W. Saanich Rd. Victoria, BCV9E 2E7 (Canada); Trujillo, Chad; Stephens, Andrew W. [Gemini Observatory, Northern Operations Center, 670 N A'ohoku Place, Hilo, HI 96720 (United States); Gimeno, German [Gemini Observatory, Southern Operations Center, c/o AURA, Casilla 603, La Serena (Chile); Brown, Michael E., E-mail: wesley.fraser@nrc.ca [California Institute of Technology, Division of Geological and Planetary Sciences, 1200 E. California Blvd., Pasadena, CA 91101 (United States)

    2013-09-10

    Here we present high cadence photometry taken by the Acquisition Camera on Gemini South, of a close passage by the {approx}540 km radius Kuiper belt object, (50000) Quaoar, of a r' = 20.2 background star. Observations before and after the event show that the apparent impact parameter of the event was 0.''019 {+-} 0.''004, corresponding to a close approach of 580 {+-} 120 km to the center of Quaoar. No signatures of occultation by either Quaoar's limb or its potential atmosphere are detectable in the relative photometry of Quaoar and the target star, which were unresolved during closest approach. From this photometry we are able to put constraints on any potential atmosphere Quaoar might have. Using a Markov chain Monte Carlo and likelihood approach, we place pressure upper limits on sublimation supported, isothermal atmospheres of pure N{sub 2}, CO, and CH{sub 4}. For N{sub 2} and CO, the upper limit surface pressures are 1 and 0.7 {mu}bar, respectively. The surface temperature required for such low sublimation pressures is {approx}33 K, much lower than Quaoar's mean temperature of {approx}44 K measured by others. We conclude that Quaoar cannot have an isothermal N{sub 2} or CO atmosphere. We cannot eliminate the possibility of a CH{sub 4} atmosphere, but place upper surface pressure and mean temperature limits of {approx}138 nbar and {approx}44 K, respectively.

  2. Tidal oscillations in Mars's atmosphere

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2013-08-01

    Atmospheric tides—global oscillations in pressure, temperature, and wind that are subharmonics of a solar day—mainly affect the upper atmosphere on Earth, but on Mars they tend to have effects throughout the atmosphere. Tidal variations in Mars's atmosphere are mainly introduced by diurnal variations in surface temperature as the planet rotates. The absorption of radiation by aerosols in the atmosphere provides an additional forcing, which complicates the tidal structure.

  3. Acoustic measurements of atmospheric electrical discharges for planetary probes

    NASA Astrophysics Data System (ADS)

    Eichelberger, H.; Prattes, G.; Schwingenschuh, K.; Jaffer, G.; Aydogar, Ö.; Jernej, I.; Besser, B.; Stachel, M.; Tokano, T.; Falkner, P.

    2010-05-01

    We present acoustic measurements carried out in a high voltage laboratory in order to characterise signals from various discharge processes, e.g. lightning or corona discharge. The investigations are in the frame of the Acoustic Sensor Package (ACU) for Titan Saturn System Mission (TSSM), a proposed post Cassini-Huygens mission. The multi-microphone system ACU has the scientific objective to characterise acoustical phenomena in Titan's atmosphere with heritage from Huygens Atmospheric Structure Instrument (HASI/PWA) on Huygens probe. We investigate the possibility to use acoustic measurements for the study of atmospheric electrical discharges. The experiments in the high voltage lab used a generator with voltages up to 1.9 million volts with different polarities. Various discharges have been generated and acoustical signals detected. From the sound signature we derive parameters which influence the technical design of ACU, e.g. filter coefficients for capturing fast transient acoustic phenomena and intermittent signals. In addition multi-microphone sound systems can be used to estimate the location of discharges.

  4. Secondary Cosmic Ray Particles due to GCR Interactions in the Earth's Atmosphere

    SciTech Connect

    Battistoni, G.; Garzelli, M. V.; Muraro, S.; Sala, P. R. [University of Milano, Department of Physics, and INFN, Milan (Italy); Cerutti, F.; Ferrari, A.; Roesler, S. [CERN, Geneva (Switzerland); Fasso, A. [SLAC, Stanford, CA (United States); Lantz, M. [Chalmers University, Department of Fundamental Physics, Goteborg (Sweden); Pinsky, L. S. [University of Houston, Department of Physics, Houston, TX (United States); Ranft, J. [Siegen University, Fachbereich 7-Physik, Siegen (Germany)

    2008-01-24

    Primary GCR interact with the Earth's atmosphere originating atmospheric showers, thus giving rise to fluxes of secondary particles in the atmosphere. Electromagnetic and hadronic interactions interplay in the production of these particles, whose detection is performed by means of complementary techniques in different energy ranges and at different depths in the atmosphere, down to the Earth's surface.Monte Carlo codes are essential calculation tools which can describe the complexity of the physics of these phenomena, thus allowing the analysis of experimental data. However, these codes are affected by important uncertainties, concerning, in particular, hadronic physics at high energy. In this paper we shall report some results concerning inclusive particle fluxes and atmospheric shower properties as obtained using the FLUKA transport and interaction code. Some emphasis will also be given to the validation of the physics models of FLUKA involved in these calculations.

  5. Quasielastic neutrino scattering from oxygen and the atmospheric neutrino problem

    SciTech Connect

    Engel, J. (Bartol Research Institute, University of Delaware, Newark, Delaware 19713 (United States)); Kolbe, E.; Langanke, K. (W. K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125 (United States)); Vogel, P. (Physics Department, California Institute of Technology, Pasadena, California 91125 (United States))

    1993-10-01

    We examine several phenomena beyond the scope of Fermi-gas models that affect the quasielastic scattering (from oxygen) of neutrinos in the 0.1--3.0 GeV range. These include Coulomb interactions of outgoing protons and leptons, a realistic finite-volume mean field, and the residual nucleon-nucleon interaction. None of these effects are accurately represented in the Monte Carlo simulations used to predict event rates due to [mu] and [ital e] neutrinos from cosmic-ray collisions in the atmosphere. We nevertheless conclude that the neglected physics cannot account for the anomalous [mu]-to-[ital e] ratio observed at Kamiokande and IMB, and is unlikely to change absolute event rates by more than 10--15 %. We briefly mention other phenomena, still to be investigated in detail, that may produce larger changes.

  6. The Atmosphere of Mars

    NSDL National Science Digital Library

    Roberta Johnson

    2000-07-01

    The Atmosphere of Mars is a Windows to the Universe Exploratour and provides information and images about composition of the Martian atmosphere, atmosphere layers, temperature, weather, clouds on Mars, clouds at the polar caps, fronts, temperature, storms on Mars, global wind, global dust storms, The Viking Mission, and the Mars Pathfinder. Windows to the Universe is a user-friendly learning system pertaining to the Earth and Space sciences. The objective of this project is to develop an innovative and engaging web site that spans the Earth and Space sciences and includes a rich array of documents, including images, movies, animations, and data sets that explore the Earth and Space sciences and the historical and cultural ties between science, exploration and the human experience. Links at the top of each page allow users to navigate between beginner, intermediate, and advanced options for each topic level.

  7. Atmospheric refraction: a history.

    PubMed

    Lehn, Waldemar H; van der Werf, Siebren

    2005-09-20

    We trace the history of atmospheric refraction from the ancient Greeks up to the time of Kepler. The concept that the atmosphere could refract light entered Western science in the second century B.C. Ptolemy, 300 years later, produced the first clearly defined atmospheric model, containing air of uniform density up to a sharp upper transition to the ether, at which the refraction occurred. Alhazen and Witelo transmitted his knowledge to medieval Europe. The first accurate measurements were made by Tycho Brahe in the 16th century. Finally, Kepler, who was aware of unusually strong refractions, used the Ptolemaic model to explain the first documented and recognized mirage (the Novaya Zemlya effect). PMID:16201423

  8. Atmospheric Pseudohalogen Chemistry

    NASA Technical Reports Server (NTRS)

    Lary, David John

    2004-01-01

    Hydrogen cyanide is not usually considered in atmospheric chemical models. The paper presents three reasons why hydrogen cyanide is likely to be significant for atmospheric chemistry. Firstly, HCN is a product and marker of biomass burning. Secondly, it is also likely that lightning is producing HCN, and as HCN is sparingly soluble it could be a useful long-lived "smoking gun" marker of lightning activity. Thirdly, the chemical decomposition of HCN leads to the production of small amounts of the cyanide (CN) and NCO radicals. The NCO radical can be photolyzed in the visible portion of the spectrum yielding nitrogen atoms (N). The production of nitrogen atoms is significant as it leads to the titration of total nitrogen from the atmosphere via N+N->N2, where N2 is molecular nitrogen.

  9. Martian atmospheric radiation budget

    NASA Technical Reports Server (NTRS)

    Lindner, Bernhard Lee

    1994-01-01

    A computer model is used to study the radiative transfer of the martian winter-polar atmosphere. Solar heating at winter-polar latitudes is provided predominately by dust. For normal, low-dust conditions, CO2 provides almost as much heating as dust. Most heating by CO2 in the winter polar atmosphere is provided by the 2.7 micron band between 10 km and 30 km altitude, and by the 2.0 micron band below 10 km. The weak 1.3 micron band provides some significant heating near the surface. The minor CO2 bands at 1.4, 1.6, 4.8 and 5.2 micron are all optically thin, and produce negligible heating. O3 provides less than 10 percent of the total heating. Atmospheric cooling is predominantly thermal emission by dust, although CO2 15 micron band emission is important above 20 km altitude.

  10. Vapor scavenging by atmospheric aerosol particles

    SciTech Connect

    Andrews, E.

    1996-05-01

    Particle growth due to vapor scavenging was studied using both experimental and computational techniques. Vapor scavenging by particles is an important physical process in the atmosphere because it can result in changes to particle properties (e.g., size, shape, composition, and activity) and, thus, influence atmospheric phenomena in which particles play a role, such as cloud formation and long range transport. The influence of organic vapor on the evolution of a particle mass size distribution was investigated using a modified version of MAEROS (a multicomponent aerosol dynamics code). The modeling study attempted to identify the sources of organic aerosol observed by Novakov and Penner (1993) in a field study in Puerto Rico. Experimentally, vapor scavenging and particle growth were investigated using two techniques. The influence of the presence of organic vapor on the particle`s hydroscopicity was investigated using an electrodynamic balance. The charge on a particle was investigated theoretically and experimentally. A prototype apparatus--the refractive index thermal diffusion chamber (RITDC)--was developed to study multiple particles in the same environment at the same time.

  11. Photochemistry of Pluto's Atmosphere

    NASA Technical Reports Server (NTRS)

    Krasnopolsky, Vladimir A.

    1999-01-01

    This work include studies of two problems: (1) Modeling thermal balance, structure. and escape processes in Pluto's upper atmosphere. This study has been completed in full. A new method, of analytic solution for the equation of hydrodynamic flow from in atmosphere been developed. It was found that the ultraviolet absorption by methane which was previously ignored is even more important in Pluto's thermal balance than the extreme ultraviolet absorption by nitrogen. Two basic models of the lower atmosphere have been suggested, with a tropopause and a planetary surface at the bottom of the stellar occultation lightcurve, respectively, Vertical profiles, of temperature, density, gas velocity, and the CH4 mixing ratio have been calculated for these two models at low, mean, and high solar activity (six models). We prove that Pluto' " s atmosphere is restricted to 3060-4500 km, which makes possible a close flyby of future spacecraft. Implication for Pluto's evolution have also been discussed. and (2) Modeling of Pluto's photochemistry. Based on the results of (1), we have made some changes in the basic continuity equation and in the boundary conditions which reflect a unique can of hydrodynamic escape and therefore have not been used in modeling of other planetary atmospheres. We model photochemistry of 44 neutral and 23 ion species. This work required solution of a set of 67 second-order nonlinear ordinary differential equations. Two models have been developed. Each model consists of the vertical profiles for 67 species, their escape and precipitation rates. These models predict the chemical structure and basic chemical processes in the current atmosphere and possible implication of these processes for evolution. This study has also been completed in full.

  12. Upper atmosphere research

    NASA Astrophysics Data System (ADS)

    Lloyd, K. H.

    From 1960 until 1977 the Weapons Research Establishment (WRE) undertook research into determining the properties of the upper atmosphere by the use of sounding rockets fired from the Woomera rocket range. This Monograph describes the experiments which were conducted. The experiments were aimed at measuring the temperature, density, constituents, ionization, and motions of the upper atmosphere between 60 and 200 km, about which at that time little was known. Many of the experiments were conducted in collaboration with Australian and overseas universities and research institutes, this work is also described.

  13. Solar atmosphere neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Fogli, G. L.; Lisi, E.; Mirizzi, A.; Montanino, D.; Serpico, P. D.

    2007-06-01

    The Sun is a source of high energy neutrinos (E>10 GeV) produced by cosmic ray interactions in the solar atmosphere. We study the impact of three-flavor oscillations on the solar atmosphere neutrino fluxes observable at Earth. We find that peculiar matter oscillation effects in the Sun do exist, but are significantly suppressed by averaging over the production region and over the neutrino and antineutrino components. In particular, the relation between the neutrino fluxes at the Sun and at the Earth can be approximately expressed in terms of phase-averaged “vacuum” oscillations, dominated by a single mixing parameter (the angle ?).

  14. Solar atmosphere neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Fogli, G. L.; Lisi, E.; Mirizzi, A.; Montanino, D.; Serpico, P. D.

    2008-07-01

    The Sun is a source of high energy neutrinos (E > 10 GeV) produced by cosmic ray interactions in the solar atmosphere. We study the impact of three-flavor oscillations on the solar atmosphere neutrino fluxes observable at Earth. We find that peculiar matter oscillation effects in the Sun do exist, but are significantly suppressed by averaging over the production region and over the neutrino and antineutrino components. In particular, the relation between the neutrino fluxes at the Sun and at the Earth can be approximately expressed in terms of phase-averaged 'vacuum' oscillations, dominated by a single mixing parameter (the angle ?23).

  15. Jupiter's outer atmosphere.

    NASA Technical Reports Server (NTRS)

    Brice, N. M.

    1973-01-01

    The current state of the theory of Jupiter's outer atmosphere is briefly reviewed. The similarities and dissimilarities between the terrestrial and Jovian upper atmospheres are discussed, including the interaction of the solar wind with the planetary magnetic fields. Estimates of Jovian parameters are given, including magnetosphere and auroral zone sizes, ionospheric conductivity, energy inputs, and solar wind parameters at Jupiter. The influence of the large centrifugal force on the cold plasma distribution is considered. The Jovian Van Allen belt is attributed to solar wind particles diffused in toward the planet by dynamo electric fields from ionospheric neutral winds, and the consequences of this theory are indicated.

  16. Solar atmosphere neutrino oscillations

    SciTech Connect

    Fogli, G.L.; Lisi, E.; Mirizzi, A.; /INFN, Bari; Montanino, D.; /INFN, Lecce; Serpico, P.D.; /Fermilab

    2007-02-01

    The Sun is a source of high energy neutrinos (E > 10 GeV) produced by cosmic ray interactions in the solar atmosphere. We study the impact of three-flavor oscillations on the solar atmosphere neutrino fluxes observable at Earth. We find that peculiar matter oscillation effects in the Sun do exist, but are significantly suppressed by averaging over the production region and over the neutrino and antineutrino components. In particular, the relation between the neutrino fluxes at the Sun and at the Earth can be approximately expressed in terms of phase-averaged ''vacuum'' oscillations, dominated by a single mixing parameter (the angle {theta}{sub 23}).

  17. Comets, meteorites and atmospheres.

    PubMed

    Owen, T; Bar-Nun, A

    1996-01-01

    The relatively low value of Xe/Kr in the atmospheres of Earth and Mars seems to rule out meteorites as the major carriers of noble gases to the inner planets. Laboratory experiments on the trapping of gases in ice forming at low temperatures suggest that comets may be a better choice. It is then possible to develop a model for the origin of inner planet atmospheres based on volatiles delivered by comets added to volatiles originally trapped in planetary rocks. The model will be tested by results from the Galileo Entry Probe. PMID:11539471

  18. Atmospheric and Oceanic Modeling

    NSDL National Science Digital Library

    Adcroft, Alistair

    The numerical methods, formulation and parameterizations used in models of the circulation of the atmosphere and ocean will be described in detail. Widely used numerical methods will be the focus but we will also review emerging concepts and new methods. The numerics underlying a hierarchy of models will be discussed, ranging from simple GFD models to the high-end GCMs. In the context of ocean GCMs, we will describe parameterization of geostrophic eddies, mixing and the surface and bottom boundary layers. In the atmosphere, we will review parameterizations of convection and large scale condensation, the planetary boundary layer and radiative transfer.

  19. Multipoint observations of plasma phenomena made in space by Cluster

    NASA Astrophysics Data System (ADS)

    Goldstein, M. L.; Escoubet, P.; Hwang, K.-Joo; Wendel, D. E.; Viñas, A.-F.; Fung, S. F.; Perri, S.; Servidio, S.; Pickett, J. S.; Parks, G. K.; Sahraoui, F.; Gurgiolo, C.; Matthaeus, W.; Weygand, J. M.

    2015-06-01

    Plasmas are ubiquitous in nature, surround our local geospace environment, and permeate the universe. Plasma phenomena in space give rise to energetic particles, the aurora, solar flares and coronal mass ejections, as well as many energetic phenomena in interstellar space. Although plasmas can be studied in laboratory settings, it is often difficult, if not impossible, to replicate the conditions (density, temperature, magnetic and electric fields, etc.) of space. Single-point space missions too numerous to list have described many properties of near-Earth and heliospheric plasmas as measured both in situ and remotely (see http://www.nasa.gov/missions/#.U1mcVmeweRY for a list of NASA-related missions). However, a full description of our plasma environment requires three-dimensional spatial measurements. Cluster is the first, and until data begin flowing from the Magnetospheric Multiscale Mission (MMS), the only mission designed to describe the three-dimensional spatial structure of plasma phenomena in geospace. In this paper, we concentrate on some of the many plasma phenomena that have been studied using data from Cluster. To date, there have been more than 2000 refereed papers published using Cluster data but in this paper we will, of necessity, refer to only a small fraction of the published work. We have focused on a few basic plasma phenomena, but, for example, have not dealt with most of the vast body of work describing dynamical phenomena in Earth's magnetosphere, including the dynamics of current sheets in Earth's magnetotail and the morphology of the dayside high latitude cusp. Several review articles and special publications are available that describe aspects of that research in detail and interested readers are referred to them (see for example, Escoubet et al. 2005 Multiscale Coupling of Sun-Earth Processes, p. 459, Keith et al. 2005 Sur. Geophys. 26, 307-339, Paschmann et al. 2005 Outer Magnetospheric Boundaries: Cluster Results, Space Sciences Series of ISSI. Berlin: Springer, Goldstein et al. 2006 Adv. Space Res. 38, 21-36, Taylor et al. 2010 The Cluster Mission: Space Plasma in Three Dimensions, Springer, pp. 309-330 and Escoubet et al. 2013 Ann. Geophys. 31, 1045-1059).

  20. A review of anode phenomena in vacuum arces

    SciTech Connect

    Miller, H.C.

    1988-09-01

    This report discusses arc modes at the anode, experimental results pertinent to anode phenomena, and theoretical explanations of anode phenomena. The dominant mechanism controlling the formation of an anode spot appears to depend upon the electrode geometry, the electrode material, and the current waveforms of the particular vacuum arc being considered. In specific experimental conditions, either magnetic constriction in the gap plasma or gross anode melting or local anode evaporation can trigger the transition. However, the most probable explanation of anode spot formation is a combination theory, which considers magnetic constriction in the plasma together with the fluxes of material from the anode and cathode as well as the thermal, electrical, and geometric effects of the anode in analyzing the behavior of the anode and the nearby plasma. 88 refs., 6 figs., 8 tabs.

  1. Protein Crystallization: Specific Phenomena and General Insights on Crystallization Kinetics

    NASA Technical Reports Server (NTRS)

    Rosenberger, F.

    1998-01-01

    Experimental and simulation studies of the nucleation and growth kinetics of proteins have revealed phenomena that are specific for macromolecular crystallization, and others that provide a more detailed understanding of solution crystallization in general. The more specific phenomena, which include metastable liquid-liquid phase separations and gelation prior to solid nucleation, are due to the small ratio of the intermolecular interaction-range to the size of molecules involved. The apparently more generally applicable mechanisms include the cascade-like formation of macrosteps, as an intrinsic morphological instability that roots in the coupled bulk transport and nonlinear interface kinetics in systems with mixed growth rate control. Analyses of this nonlinear response provide (a) criteria for the choice of bulk transport conditions to minimize structural defect formation, and (b) indications that the "slow" protein crystallization kinetics stems from the mutual retardation of growth steps.

  2. Emergent topological phenomena in thin films of pyrochlore iridates

    NASA Astrophysics Data System (ADS)

    Yang, Bohm Jung; Nagaosa, Naoto

    2014-03-01

    With the recent development of thin film and artificial superstructure growth technique, it is possible to fabricate a system, moothly connecting the two-dimensions (2D) and three-dimensions (3D). In this work we unveil the dimensional crossover of emergent topological phenomena. In particular, by focusing on the thin film of pyrochlore iridate antiferromagnets grown along the [111] direction, we demonstrate that it can show giant anomalous Hall conductance, which is as large as the Hall conductance of 3D quantum Hall insulators, even though there is no Hall effect in 3D bulk material. In addition, we show the emergence of a genuine new topological phase, dubbed the anti-Chern insulator, which is realized only in thin films. This shows that the thin film of topological materials is a new platform to search unexplored novel topological phenomena.

  3. Phenomena associated with magma expansion into a drift

    SciTech Connect

    Gaffney, E. S. (Edward S.)

    2002-01-01

    One of the significant threats to the proposed Yucca Mountain nuclear waste repository has been identified as the possibility of intersection of the underground structure by a basaltic intrusion. Based on the geology of the region, it is assumed that such an intrusion would consist of an alkali basalt similar to the nearby Lathrop Wells cone, which has been dated at about 78 ka. The threat of radioactive release may be either from eruption through the surface above the repository of basalt that had been contaminated or from migration through ground water of radionucleides released as a result of damage to waste packages that interact with the magma. As part of our study of these threats, we are analyzing the phenomena associated with magma expansion into drifts in tuff. The early phenomena of the encounter of volatile-rich basaltic magma with a drift are discussed here.

  4. Critical phenomena in heterogeneous k-core percolation

    NASA Astrophysics Data System (ADS)

    Cellai, Davide; Lawlor, Aonghus; Dawson, Kenneth A.; Gleeson, James P.

    2013-02-01

    k-core percolation is a percolation model which gives a notion of network functionality and has many applications in network science. In analyzing the resilience of a network under random damage, an extension of this model is introduced, allowing different vertices to have their own degree of resilience. This extension is named heterogeneous k-core percolation and it is characterized by several interesting critical phenomena. Here we analytically investigate binary mixtures in a wide class of configuration model networks and categorize the different critical phenomena which may occur. We observe the presence of critical and tricritical points and give a general criterion for the occurrence of a tricritical point. The calculated critical exponents show cases in which the model belongs to the same universality class of facilitated spin models studied in the context of the glass transition.

  5. Observation of microwave superfluid phenomena of multiple phase magnetic fluid

    NASA Astrophysics Data System (ADS)

    Kono, Kazuhito; Kono, Buhei

    2015-05-01

    We observe superfluid phenomena by microwaves irradiation to multiple phase magnetic fluid in room temperature or room pressure. Ferromagnetism transformation of diamagnetic or paramagnetic particles in multiple phase magnetic fluid containing constant rate of ferromagnetic particles, diamagnetic or paramagnetic particles mixing organic polyphenol and irradiation of microwaves is, observed by superexchange interaction. Superfluid phenomena are observed by irradiation of microwaves to aforementioned multiple phase of magnetic fluid containing ferromagnetism transformed diamagnetic or paramagnetic particles with ferromagnetic particles. Mixing semiconductor pigments amplifying superfluid energy by photosensitivity is observed. Visible light LED selecting wavelength is irradiated to superfluid condition of aforementioned multiple phase magnetic fluid thus magnetic field and energy of superfluid is enhanced by light quantum amplification effect.

  6. The function of nonlinear phenomena in meerkat alarm calls

    PubMed Central

    Townsend, Simon W.; Manser, Marta B.

    2011-01-01

    Nonlinear vocal phenomena are a ubiquitous feature of human and non-human animal vocalizations. Although we understand how these complex acoustic intrusions are generated, it is not clear whether they function adaptively for the animals producing them. One explanation is that nonlinearities make calls more unpredictable, increasing behavioural responses and ultimately reducing the chances of habituation to these call types. Meerkats (Suricata suricatta) exhibit nonlinear subharmonics in their predator alarm calls. We specifically tested the ‘unpredictability hypothesis’ by playing back naturally occurring nonlinear and linear medium-urgency alarm call bouts. Results indicate that subjects responded more strongly and foraged less after hearing nonlinear alarm calls. We argue that these findings support the unpredictability hypothesis and suggest this is the first study in animals or humans to show that nonlinear vocal phenomena function adaptively. PMID:20659926

  7. ESM of Ionic and Electrochemical Phenomena on the Nanoscale

    SciTech Connect

    Kalinin, Sergei V. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Kumar, Amit [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Balke, Nina [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); McCorkle, Morgan [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Guo, Senli [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Arruda, Thomas M. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Jesse, Stephen [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

    2011-11-01

    Operation of energy storage and conversion devices is ultimately controlled by series of intertwined ionic and electronic transport processes and electrochemical reactions at surfaces and interfaces, strongly mediated by strain and mechanical processes. In a typical fuel cell, these include chemical species transport in porous cathode and anode materials, gas-solid electrochemical reactions at grains and triple-phase boundaries (TPBs), ionic and electronic flows in multicomponent electrodes, and chemical and electronic potential drops at internal interfaces in electrodes and electrolytes. All these phenomena are sensitively affected by the microstructure of materials from device level to the atomic scales. Similar spectrum of length scales and phenomena underpin operation of other energy systems including primary and secondary batteries, as well as hybrid systems such flow and metal-air/water batteries.

  8. Two-Phase Lattice Boltzmann Modeling of Boiling Phenomena

    NASA Astrophysics Data System (ADS)

    Mohammadi Shad, Mahmood; Lee, Taehun; Kawaji, Masahiro

    2013-11-01

    Modern advanced technologies such as electronics cooling need large heat removal from surfaces. Nucleate boiling phenomena provides sufficient cooling for these purposes because of large value of latent heat stored in the liquid. A modified multiphase lattice Boltzmann equation model is developed for liquid-vapor phase change phenomena. The volumetric mass flow rate at the interface due to phase change is included in the non-zero value of divergence of velocity. The evolution equation for hydrodynamic pressure is used to force the incompressibility in the bulk regions and the compressibility in the interfacial region. The one-dimensional Stefan problem with analytical solution is used to validate the proposed model and the two-dimensional nucleate boiling on a flat surface is simulated as the main case study.

  9. Concepts and methods for describing critical phenomena in fluids

    NASA Technical Reports Server (NTRS)

    Sengers, J. V.; Sengers, J. M. H. L.

    1977-01-01

    The predictions of theoretical models for a critical-point phase transistion in fluids, namely the classical equation with third-degree critical isotherm, that with fifth-degree critical isotherm, and the lattice gas, are reviewed. The renormalization group theory of critical phenomena and the hypothesis of universality of critical behavior supported by this theory are discussed as well as the nature of gravity effects and how they affect cricital-region experimentation in fluids. The behavior of the thermodynamic properties and the correlation function is formulated in terms of scaling laws. The predictions of these scaling laws and of the hypothesis of universality of critical behavior are compared with experimental data for one-component fluids and it is indicated how the methods can be extended to describe critical phenomena in fluid mixtures.

  10. High spatial resolution measurements of ram accelerator gas dynamic phenomena

    NASA Technical Reports Server (NTRS)

    Hinkey, J. B.; Burnham, E. A.; Bruckner, A. P.

    1992-01-01

    High spatial resolution experimental tube wall pressure measurements of ram accelerator gas dynamic phenomena are presented. The projectile resembles the centerbody of a ramjet and travels supersonically through a tube filled with a combustible gaseous mixture, with the tube acting as the outer cowling. Pressure data are recorded as the projectile passes by sensors mounted in the tube wall at various locations along the tube. Data obtained by using a special highly instrumented section of tube has allowed the recording of gas dynamic phenomena with a spatial resolution on the order of one tenth the projectile length. High spatial resolution tube wall pressure data from the three regimes of propulsion studied to date (subdetonative, transdetonative, and superdetonative) are presented and reveal the 3D character of the flowfield induced by projectile fins and the canting of the projectile body relative to the tube wall. Also presented for comparison to the experimental data are calculations made with an inviscid, 3D CFD code.

  11. Scaling relations and multicritical phenomena from functional renormalization

    NASA Astrophysics Data System (ADS)

    Boettcher, Igor

    2015-06-01

    We investigate multicritical phenomena in O (N )+O (M ) models by means of nonperturbative renormalization group equations. This constitutes an elementary building block for the study of competing orders in a variety of physical systems. To identify possible multicritical points in phase diagrams with two ordered phases, we compute the stability of isotropic and decoupled fixed point solutions from scaling potentials of single-field models. We verify the validity of Aharony's scaling relation within the scale-dependent derivative expansion of the effective average action. We discuss implications for the analysis of multicritical phenomena with truncated flow equations. These findings are an important step towards studies of competing orders and multicritical quantum phase transitions within the framework of functional renormalization.

  12. A naming convention for atmospheric organic aerosol

    NASA Astrophysics Data System (ADS)

    Murphy, B. N.; Donahue, N. M.; Robinson, A. L.; Pandis, S. N.

    2014-06-01

    While the field of atmospheric organic aerosol scientific research has experienced thorough and insightful progress over the last half century, this progress has been accompanied by the evolution of a communicative and detailed yet, at times, complex and inconsistent language. The menagerie of detailed classification that now exists to describe organic compounds in our atmosphere reflects the wealth of observational techniques now at our disposal as well as the rich information provided by state-of-the-science instrumentation. However, the nomenclature in place to communicate these scientific gains is growing disjointed to the point that effective communication within the scientific community and to the public may be sacrificed. We propose standardizing a naming convention for organic aerosol classification that is relevant to laboratory studies, ambient observations, atmospheric models, and various stakeholders for air-quality problems. Because a critical aspect of this effort is to directly translate the essence of complex physico-chemical phenomena to a much broader, policy-oriented audience, we recommend a framework that maximizes comprehension among scientists and non-scientists alike. For example, to classify volatility, it relies on straightforward alphabetic terms (e.g., semivolatile, SV; intermediate volatility, IV; etc.) rather than possibly ambiguous numeric indices. This framework classifies organic material as primary or secondary pollutants and distinguishes among fundamental features important for science and policy questions including emission source, chemical phase, and volatility. Also useful is the addition of an alphabetic suffix identifying the volatility of the organic material or its precursor for when emission occurred. With this framework, we hope to introduce into the community a consistent connection between common notation for the general public and detailed nomenclature for highly specialized discussion. In so doing, we try to maintain consistency with historical, familiar naming schemes, unify much of the scattered nomenclature presented in recent literature, reduce the barrier of comprehension to outside audiences, and construct a scaffold into which insights from future scientific discoveries can be incorporated.

  13. Helium in the Atmosphere

    Microsoft Academic Search

    William Crookes

    1898-01-01

    THE letter of Mr. Baly in your issue of last week, corroborating the statement of Friedländer and Kayser that helium is a constituent of the atmosphere, induces me to put on record a further confirmation of the accuracy of this observation. Having had the opportunity, on June 20 last, of examining samples of the more volatile portions from liquid air,

  14. Laboratory for Atmospheric and

    E-print Network

    Mojzsis, Stephen J.

    Laboratory for Atmospheric and Space Physics Activity Report 2012 University of Colorado at Boulder from the Naval Research Center and the Air Force Cambridge Research Laboratory (now the Phillips Laboratory), the University of Colorado formed a research group called the Upper Air Laboratory (UAL

  15. Halogens in the atmosphere

    Microsoft Academic Search

    Ralph J. Cicerone

    1981-01-01

    Extant data from measurements of halogens in the atmosphere are reviewed in the following categories: gaseous chlorine compounds (inorganic and organic), particulate chloride and chloride in precipitation, gaseous bromine compounds (inorganic and organic), particulate bromide and bromide in precipitation, gaseous iodine compounds (inorganic and organic), iodine in particles and in precipitation, gaseous fluorine compounds (inorganic and organic), and fluoride in

  16. NATIONALOCEAN AND ATMOSPHERIC

    E-print Network

    NATIONALOCEAN IC AND ATMOSPHERIC ADMINISTRATION U.S. D EPARTMENT OF COMM E R CE Great Lakes the Great Lakes water level story is an important part of NOAA's mission to understand and predict changes in climate, weather, oceans, and coasts. The Great Lakes Hydro-Climate Dashboard is an interactive web

  17. Spectra of Atmospheric Scalars

    Microsoft Academic Search

    Earl E. Gossard

    1960-01-01

    In Part 1 a wide-band spectrum of atmospheric pressure extending from periods of i week to 0.2 second is shown. The various frequency ranges are discussed with particular atten- tion given to the midfrequency range. It is shown that convective activity and internal gravity waves can greatly modify the normal spectral distribution at midfrequencies and a specific example is discussed

  18. Integrated atmospheric characterization system

    Microsoft Academic Search

    David W. Roberts; Gary G. Gimmestad; John M. Stewart; David N. Whiteman; Frank D. Eaton

    2009-01-01

    The Georgia Tech Research Institute (GTRI) is developing a transportable multi-lidar instrument known as the Integrated Atmospheric Characterization System (IACS). The system will be housed in standard shipping containers that will be transported to remote sites by tractor-trailer. IACS will comprise three lidars: a 355 nm imaging lidar for profiling refractive turbulence, a 355 nm Raman lidar for profiling water

  19. Differential atmospheric tritium sampler

    Microsoft Academic Search

    Otto A. Griesbach; Joseph R. Stencel

    1990-01-01

    An atmospheric tritium sampler is provided which uses a carrier gas comprised of hydrogen gas and a diluting gas, mixed in a nonexplosive concentration. Sample air and carrier gas are drawn into and mixed in a manifold. A regulator meters the carrier gas flow to the manifold. The air sample\\/carrier gas mixture is pulled through a first moisture trap which

  20. Differential atmospheric tritium sampler

    Microsoft Academic Search

    O. A. Griesbach; J. R. Stencel

    1987-01-01

    An atmospheric tritium sampler is provided which uses a carrier gas comprised of hydrogen gas and a diluting gas, mixed in a nonexplosive concentration. Sample air and carrier gas are drawn into and mixed in a manifold. A regulator meters the carrier gas flow to the manifold. The air sample\\/carrier gas mixture is pulled through a first moisture trap which

  1. Atmospheric ray tracing

    Microsoft Academic Search

    B. G. Roberts Jr.; E. H. Bebbs

    1974-01-01

    A computer program has been written in FORTRAN to predict the acoustical ray paths in the atmosphere, as well as determining the transmission loss in air. The program accepts data in the form of a temperature or sound speed versus height profile. A wind velocity profile may also be entered. The program will produce a printplot of the ray trajectories,

  2. Earth's Earliest Atmospheres

    Microsoft Academic Search

    Kevin Zahnle; Laura Schaefer; Bruce Fegley

    2010-01-01

    Earth is the one known example of an inhabited planet and to current knowledge the likeliest site of the one known origin of life. Here we discuss the origin of Earth's atmosphere and ocean and some of the environmental conditions of the early Earth as they may relate to the origin of life. A key punctuating event in the narrative

  3. Lunar atmospheric composition experiment

    NASA Technical Reports Server (NTRS)

    Hoffman, J. H.

    1975-01-01

    Apollo 17 carried a miniature mass spectrometer, called the Lunar Atmospheric Composition Experiment (LACE), to the moon as part of the Apollo Lunar Surface Experiments Package (ALSEP) to study the composition and variations in the lunar atmosphere. The instrument was successfully deployed in the Taurus-Littrow Valley with its entrance aperture oriented upward to intercept and measure the downward flux of gases at the lunar surface. During the ten lunations that the LACE operated, it produced a large base of data on the lunar atmosphere, mainly collected at night time. It was found that thermal escape is the most rapid loss mechanism for hydrogen and helium. For heavier gases, photoionization followed by acceleration through the solar wind electric field accounted for most of the loss. The dominant gases on the moosn were argon and helium, and models formed for their distribution are described in detail. It is concluded that most of the helium in the lunar atmosphere is of solar wind origin, and that there also exist very small amounts of methane, ammonia, and carbon dioxide.

  4. Controlled atmosphere soldering system

    SciTech Connect

    Keicher, D.M.; Hernandez, C.L.; Frear, D.R.; Hosking, F.M.

    1992-06-01

    We have developed a controlled environment system in which to perform wetting experiments to analyze the effects of various atmospheres, both inert and reducing, on solder processing. This system consists of a custom designed vacuum chamber, an apparatus for heating specimens and a video system for data acquisition. The system design allows for rapid changes to various processing atmospheres. Specimens can be heated to soldering temperature from room temperature rapidly. The temperature is regulated by a controller which gives a maximum heating rate of 23{degrees}C/second while minimizing the amount of overshoot, thereby quickly a stabilized temperature. A video system is used to acquire the data in the form of both numerical data and real-time video images. The video system allows multiple views of the wetting process to be captured and simultaneously records time and temperature information. The recorded information is suitable for digital analysis. The controlled atmosphere soldering system has been used to perform experiments that examine the effect of inert and acid vapor atmospheres on solder wetting behavior.

  5. Controlled atmosphere soldering system

    SciTech Connect

    Keicher, D.M.; Hernandez, C.L.; Frear, D.R.; Hosking, F.M.

    1992-01-01

    We have developed a controlled environment system in which to perform wetting experiments to analyze the effects of various atmospheres, both inert and reducing, on solder processing. This system consists of a custom designed vacuum chamber, an apparatus for heating specimens and a video system for data acquisition. The system design allows for rapid changes to various processing atmospheres. Specimens can be heated to soldering temperature from room temperature rapidly. The temperature is regulated by a controller which gives a maximum heating rate of 23{degrees}C/second while minimizing the amount of overshoot, thereby quickly a stabilized temperature. A video system is used to acquire the data in the form of both numerical data and real-time video images. The video system allows multiple views of the wetting process to be captured and simultaneously records time and temperature information. The recorded information is suitable for digital analysis. The controlled atmosphere soldering system has been used to perform experiments that examine the effect of inert and acid vapor atmospheres on solder wetting behavior.

  6. ATMOSPHERIC DEPOSITION MONITORING PROGRAM

    EPA Science Inventory

    Because toxic air pollutants tend to bioaccumulate through the food chain and are persistent in the environment, when eaten, they pose a threat to humans. Atmospheric monitoring for toxic pollutants allows the tracking of toxic air pollutant transport. Many of these pollutants...

  7. Fourth DOE Natural Phenomena Hazards Mitigation Conference: Proceedings. Volume 1

    SciTech Connect

    Not Available

    1993-12-31

    This conference allowed an interchange in the natural phenomena area among designers, safety professionals, and managers. The papers presented in Volume I of the proceedings are from sessions I - VIII which cover the general topics of: DOE standards, lessons learned and walkdowns, wind, waste tanks, ground motion, testing and materials, probabilistic seismic hazards, risk assessment, base isolation and energy dissipation, and lifelines and floods. Individual papers are indexed separately. (GH)

  8. Search for Higgs and new phenomena at colliders

    SciTech Connect

    Lammel, Stephan; /Fermilab

    2006-01-01

    The present status of searches for the Higgs boson(s) and new phenomena is reviewed. The focus is on analyses and results from the current runs of the HERA and Tevatron experiments. The LEP experiments have released their final combined MSSM Higgs results for this conference. Also included are results from sensitivity studies of the LHC experiments and lepton flavor violating searches from the B factories, KEKB and PEP-II.

  9. Numerical Simulation of Low Mach Number Fluid - Phenomena

    Microsoft Academic Search

    Scott H. Reitsma

    1994-01-01

    A method for the numerical simulation of low Mach number (M) fluid-acoustic phenomena is developed. This computational fluid-acoustic (CFA) methodology is based upon a set of conservation equations, termed finite-compressible, derived from the unsteady Navier-Stokes equations. The finite-compressible and more familiar pseudo-compressible equations are compared. The impact of derivation assumptions are examined theoretically and through numerical experimentation. The error associated

  10. Infrared thermometry study of nanofluid pool boiling phenomena

    Microsoft Academic Search

    Craig Gerardi; Jacopo Buongiorno; Lin-Wen Hu; Thomas McKrell

    2011-01-01

    Infrared thermometry was used to obtain first-of-a-kind, time- and space-resolved data for pool boiling phenomena in water-based\\u000a nanofluids with diamond and silica nanoparticles at low concentration (<0.1 vol.%). In addition to macroscopic parameters\\u000a like the average heat transfer coefficient and critical heat flux [CHF] value, more fundamental parameters such as the bubble\\u000a departure diameter and frequency, growth and wait times,

  11. Mapped Chebyshev pseudospectral method to study multiple scale phenomena

    Microsoft Academic Search

    Adrian Alexandrescu; Alfonso Bueno-Orovio; Jose R. Salgueiro; Victor M. Perez-Garcia

    2007-01-01

    In the framework of mapped pseudospectral methods, we introduce a new\\u000apolynomial-type mapping function in order to describe accurately the dynamics\\u000aof systems developing almost singular structures. Using error criteria related\\u000ato the spectral interpolation error, the new polynomial-type mapping is\\u000acompared against previously proposed mappings for the study of collapse and\\u000ashock wave phenomena. As a physical application, we

  12. Simulating Microscopic Hydrodynamic Phenomena with Dissipative Particle Dynamics

    Microsoft Academic Search

    P. J. Hoogerbrugge; J. M. V. A. Koelman

    1992-01-01

    We present a novel method for simulating hydrodynamic phenomena. This particle-based method combines features from molecular dynamics and lattice-gas automata. It is shown theoretically as well as in simulations that a quantitative description of isothermal Navier-Stokes flow is obtained with relatively few particles. Computationally, the method is much faster than molecular dynamics, and the at same time it is much

  13. Reduced Order Models for Fluid-Structure Interaction Phenomena

    NASA Astrophysics Data System (ADS)

    Gallardo, Daniele

    With the advent of active flow control devices for regulating the structural responses of systems involving fluid-structure interaction phenomena, there is a growing need of efficient models that can be used to control the system. The first step is then to be able to model the system in an efficient way based on reduced-order models. This is needed so that accurate predictions of the system evolution could be performed in a fast manner, ideally in real time. However, existing reduced-order models of fluid-structure interaction phenomena that provide closed-form solutions are applicable to only a limited set of scenarios while for real applications high-fidelity experiments or numerical simulations are required, which are unsuitable as efficient or reduced-order models. This thesis proposes a novel reduced-order and efficient model for fluid-structure interaction phenomena. The model structure employed is such that it is generic for different fluid-structure interaction problems. Based on this structure, the model is first built for a given fluid-structure interaction problem based on a database generated through high-fidelity numerical simulations while it can subsequently be used to predict the structural response over a wide set of flow conditions for the fluid-structure interaction problem at hand. The model is tested on two cases: a cylinder suspended in a low Reynolds number flow that includes the lock-in region and an airfoil subjected to plunge oscillations in a high Reynolds number regime. For each case, in addition to training profile we also present validation profiles that are used to determine the performance of the reduced-order model. The reduced-order model devised in this study proved to be an effective and efficient modeling method for fluid-structure interaction phenomena and it shown its applicability in very different kind of scenarios.

  14. Defluidization phenomena during the pyrolysis of two plastic wastes

    Microsoft Academic Search

    Umberto Arena; Maria Laura Mastellone

    2000-01-01

    A couple of commercially available packaging-derived fuels, both obtained as a result of mono-material recycling programs of polyethylene (PE) and polyethylene terephthalate (PET), were fed in a laboratory scale bubbling fluidized-bed reactor, made of quartz. The effect of the main operating variables (bed solids hold-up, inert material size, fluidizing velocity, plastics feed rate) on the agglomeration and the defluidization phenomena

  15. Popcorn phenomena in a ball grid array package

    Microsoft Academic Search

    Seung-Ho Ahn; Young-Shin Kwon; Kwang-Jae Shin

    1994-01-01

    For the purpose of studying popcorn phenomena, plastic ball grid array packages with 119 I\\/O's were tested under the pre-conditioning test conditions. Observations using scanning acoustic tomography and optical microscopy were carried out to investigate the existence of delaminations and cracks in the package, and the cracking patterns after IR reflow. Package deformations and thermo-mechanical stress distributions in the package

  16. Stochastic modeling of coherent phenomena in strongly inhomogeneous media

    Microsoft Academic Search

    V. L. Kuz’min; I. V. Meglinski; D. Yu. Churmakov

    2005-01-01

    A procedure of numerical simulation for coherent phenomena in multiply scattering media is developed on the basis of the juxtaposition\\u000a of a Monte Carlo stochastic method with an iterative approach to the solution of the Bethe-Salpeter equation. The time correlation\\u000a function and the interference component of coherent backscattering are calculated for scalar and electromagnetic fields. The\\u000a results of simulation are

  17. Structure for identifying, locating and quantifying physical phenomena

    DOEpatents

    Richardson, John G.

    2006-10-24

    A method and system for detecting, locating and quantifying a physical phenomena such as strain or a deformation in a structure. A minimum resolvable distance along the structure is selected and a quantity of laterally adjacent conductors is determined. Each conductor includes a plurality of segments coupled in series which define the minimum resolvable distance along the structure. When a deformation occurs, changes in the defined energy transmission characteristics along each conductor are compared to determine which segment contains the deformation.

  18. Draft tube flow phenomena across the bulb turbine hill chart

    NASA Astrophysics Data System (ADS)

    Duquesne, P.; Fraser, R.; Maciel, Y.; Aeschlimann, V.; Deschênes, C.

    2014-03-01

    In the framework of the BulbT project launched by the Consortium on Hydraulic Machines and the LAMH (Hydraulic Machine Laboratory of Laval University) in 2011, an intensive campaign to identify flow phenomena in the draft tube of a model bulb turbine has been done. A special focus was put on the draft tube component since it has a particular importance for recuperation in low head turbines. Particular operating points were chosen to analyse flow phenomena in this component. For each of these operating points, power, efficiency and pressure were measured following the IEC 60193 standard. Visualizations, unsteady wall pressure and efficiency measurements were performed in this component. The unsteady wall pressure was monitored at seven locations in the draft tube. The frequency content of each pressure signal was analyzed in order to characterize the flow phenomena across the efficiency hill chart. Visualizations were recorded with a high speed camera using tufts and cavitation bubbles as markers. The predominant detected phenomena were mapped and categorized in relation to the efficiency hill charts obtained for three runner blade openings. At partial load, the vortex rope was detected and characterized. An inflection in the partial load efficiency curves was found to be related to complex vortex rope instabilities. For overload conditions, the efficiency curves present a sharp drop after the best efficiency point, corresponding to an inflection on the power curves. This break off is more severe towards the highest blade openings. It is correlated to a flow separation at the wall of the draft tube. Also, due to the separation occurring in these conditions, a hysteresis effect was observed on the efficiency curves.

  19. Experimental and computational simulation of in-flight icing phenomena

    NASA Astrophysics Data System (ADS)

    Kind, R. J.; Potapczuk, M. G.; Feo, A.; Golia, C.; Shah, A. D.

    1998-07-01

    This paper reviews experimental and computational methods used for simulation of ice accretion on aircraft flying through icing conditions. Such methods were recently reviewed by the AGARD FDP Working Group 20 and the present paper represents a revised and updated version of parts of the Working Group report. To provide essential background, it begins with a brief physical description of the ice accretion process. Experimental simulations must respect certain similarity requirements or scaling laws if they are to be valid; these requirements are discussed in some detail and in the framework of this discussion, physical phenomena are considered in more detail as well. Techniques and ground-based facilities for experimental simulation of ice-accretion phenomena are then reviewed, followed by a review of techniques and facilities used for flight testing in support of aircraft design and certification for flight in icing conditions. Available instruments for required measurements such as droplet size distribution and liquid water content and for inflight ice detection are briefly described. Computational simulation is becoming increasingly important in aircraft icing work; computational methods are used to simulate ice accretion both with and without iceprotection systems in operation. Computational approaches are outlined and current capabilities are evaluated. Conclusions emerging from the review include the following: rime icing is reasonably well understood and can be adequately simulated for most practical purposes using either experimental or computational methods; some of the physical phenomena known to be important in glaze icing are only poorly understood and there is considerable uncertainty regarding whether or not certain other phenomena are important; consequently, much additional research is required before reduced-scale experimental simulations or computational simulations of glaze icing will be sufficiently accurate and reliable for most practical purposes. Research recommendations are put forward.

  20. Seismically-induced sloshing phenomena in LMFBR reactor tanks

    SciTech Connect

    Ma, D.C.; Liu, W.K.; Gvildys, J.; Chang, Y.W.

    1982-01-01

    A coupled fluid-structure interaction solution procedure for analyzing seismically-induced sloshing phenomena in fluid-tank systems is presented. Both rigid and flexible tanks are considered. Surface-wave effects are also included. Results demonstrate that tank flexibility could affect the free surface-wave amplitude and the sloshing pressuare if the natural frequency of the fluid-structure system is below 5 Hz. Furthermore, the presence of higher sloshing modes do enhance the post-earthquake sloshing response.

  1. Prediction of fading phenomena in land-satellite communication links

    Microsoft Academic Search

    N. Blaunstein; Y. Cohen; M. Hayakawa

    2010-01-01

    This paper addresses the problem of prediction of probability of successful radio communication of any mobile or stationary subscriber located in areas of service such as complex urban environments characterized by nonline-of-sight propagation conditions, which limit GPS, Low Earth Orbit, and Medium Earth Orbit services in land-satellite communications. It presents a self-consistent physical-statistical approach for predicting fading phenomena usually occurring

  2. First experimental observation of generalized synchronization phenomena in microwave oscillators.

    PubMed

    Dmitriev, Boris S; Hramov, Alexander E; Koronovskii, Alexey A; Starodubov, Andrey V; Trubetskov, Dmitriy I; Zharkov, Yurii D

    2009-02-20

    In this Letter, we report for the first time on the experimental observation of the generalized synchronization regime in the microwave electronic systems, namely, in the multicavity klystron generators. A new approach devoted to the generalized synchronization detection has been developed. The experimental observations are in the excellent agreement with the results of numerical simulation. The observed phenomena gives a strong potential for new applications requiring microwave chaotic signals. PMID:19257673

  3. Analysis of Seismic Electromagnetic Phenomena Using the FDTD Method

    Microsoft Academic Search

    Yi Wang; Qunsheng Cao

    2011-01-01

    Anomalous electromagnetic (EM) phenomena of the ultra-low frequency (ULF) and the extremely low frequency (ELF) prior to or during earthquakes are analyzed using the geodesic fi- nite-difference time-domain (FDTD) algorithm and accurate ge- ological EM data. Firstly, the underground EM eruption caused by the earthquake physical process is simulated, and its effects on the surface EM field are analyzed.Based on

  4. Prediction of fading phenomena in land-satellite communication links

    NASA Astrophysics Data System (ADS)

    Blaunstein, N.; Cohen, Y.; Hayakawa, M.

    2010-12-01

    This paper addresses the problem of prediction of probability of successful radio communication of any mobile or stationary subscriber located in areas of service such as complex urban environments characterized by nonline-of-sight propagation conditions, which limit GPS, Low Earth Orbit, and Medium Earth Orbit services in land-satellite communications. It presents a self-consistent physical-statistical approach for predicting fading phenomena usually occurring in land-satellite communication links caused by influence of the terrain features on radio signal propagation from the ground-based to the satellite antenna. This approach combines (1) the statistical description of the buildings array located on the rough terrain and the buildings' overlay profile, based on special probabilistic distributions of built-up terrain parameters, and (2) the theoretical description of propagation phenomena, taking into account multiple scattering, reflection, and diffraction mechanisms. A new technique is proposed for predicting the probability of fading phenomena occurring in land-satellite links using the so-called stochastic multiparametric model. Results of theoretical predictions are compared with those obtained from the "pure statistical" Lutz model and physical-statistical Saunders-Evans model, and then with experimental data obtained for different European cities. Obtained results show that the proposed stochastic approach can be used as a good predictor of fading phenomena in land-satellite communication links for different satellite constellation scenarios and elevations of satellites during their movement surrounding the Earth, with respect to the ground-based antenna for different land environments: rural, mixed residential, suburban, and urban.

  5. Percolation Models of Self-Organized Critical Phenomena

    E-print Network

    Alexander V. Milovanov

    2012-07-23

    In this chapter of the e-book "Self-Organized Criticality Systems" we summarize some theoretical approaches to self-organized criticality (SOC) phenomena that involve percolation as an essential key ingredient. Scaling arguments, random walk models, linear-response theory, and fractional kinetic equations of the diffusion and relaxation type are presented on an equal footing with theoretical approaches of greater sophistication, such as the formalism of discrete Anderson nonlinear Schr\\"odinger equation, Hamiltonian pseudochaos, conformal maps, and fractional derivative equations of the nonlinear Schr\\"odinger and Ginzburg-Landau type. Several physical consequences are described which are relevant to transport processes in complex systems. It is shown that a state of self-organized criticality may be unstable against a bursting ("fishbone") mode when certain conditions are met. Finally we discuss SOC-associated phenomena, such as: self-organized turbulence in the Earth's magnetotail (in terms of the "Sakura" model), phase transitions in SOC systems, mixed SOC-coherent behavior, and periodic and auto-oscillatory patterns of behavior. Applications of the above pertain to phenomena of magnetospheric substorm, market crashes, and the global climate change and are also discussed in some detail. Finally we address the frontiers in the field in association with the emerging projects in fusion research and space exploration.

  6. Scaling phenomena in the Internet: Critically examining criticality

    PubMed Central

    Willinger, Walter; Govindan, Ramesh; Jamin, Sugih; Paxson, Vern; Shenker, Scott

    2002-01-01

    Recent Internet measurements have found pervasive evidence of some surprising scaling properties. The two we focus on in this paper are self-similar scaling in the burst patterns of Internet traffic and, in some contexts, scale-free structure in the network's interconnection topology. These findings have led to a number of proposed models or “explanations” of such “emergent” phenomena. Many of these explanations invoke concepts such as fractals, chaos, or self-organized criticality, mainly because these concepts are closely associated with scale invariance and power laws. We examine these criticality-based explanations of self-similar scaling behavior—of both traffic flows through the Internet and the Internet's topology—to see whether they indeed explain the observed phenomena. To do so, we bring to bear a simple validation framework that aims at testing whether a proposed model is merely evocative, in that it can reproduce the phenomenon of interest but does not necessarily capture and incorporate the true underlying cause, or indeed explanatory, in that it also captures the causal mechanisms (why and how, in addition to what). We argue that the framework can provide a basis for developing a useful, consistent, and verifiable theory of large networks such as the Internet. Applying the framework, we find that, whereas the proposed criticality-based models are able to produce the observed “emergent” phenomena, they unfortunately fail as sound explanations of why such scaling behavior arises in the Internet. PMID:11875212

  7. Replication Unreliability in Psychology: Elusive Phenomena or “Elusive” Statistical Power?

    PubMed Central

    Tressoldi, Patrizio E.

    2012-01-01

    The focus of this paper is to analyze whether the unreliability of results related to certain controversial psychological phenomena may be a consequence of their low statistical power. Applying the Null Hypothesis Statistical Testing (NHST), still the widest used statistical approach, unreliability derives from the failure to refute the null hypothesis, in particular when exact or quasi-exact replications of experiments are carried out. Taking as example the results of meta-analyses related to four different controversial phenomena, subliminal semantic priming, incubation effect for problem solving, unconscious thought theory, and non-local perception, it was found that, except for semantic priming on categorization, the statistical power to detect the expected effect size (ES) of the typical study, is low or very low. The low power in most studies undermines the use of NHST to study phenomena with moderate or low ESs. We conclude by providing some suggestions on how to increase the statistical power or use different statistical approaches to help discriminate whether the results obtained may or may not be used to support or to refute the reality of a phenomenon with small ES. PMID:22783215

  8. Neutral gas plasma interactions and critical ionization velocity phenomena

    NASA Astrophysics Data System (ADS)

    Papadopoulos, K.

    1983-11-01

    The interplay of collisional and collisionless phenomena in the interaction of a magnetoplasma streaming through neutral gas produces some of the most fascinating plasma physics phenomena. A key notion controlling such interactions is the existence of a critical velocity (U sub c) effect postulated in an ad hoc fashion by Alfven, in his model of the formation of the solar system. According to Alfven's postulate, whenever the relative velocity between a neutral gas and a streaming magnetoplasma exceeds a value U sub c identical with Square root of (2Esub i/M), where E sub i is the ionization energy and M the mass of the neutral atoms, rapid ionization and anomalous momentum coupling occurs. Guided by recent laboratory and space experiments and plasma physics theory we present the basic plasma physics underlying the interaction. This is followed by a discussion of its relevance to the formation of the solar system and cometary tails, its controlling effect on plasma centrifuges and homopolar generators, and the fascinating possibility that critical velocity phenomena are controlling the space shuttle environment, transforming it into an artificial comet.

  9. Intervention in biological phenomena modeled by S-systems.

    PubMed

    Meskin, Nader; Nounou, Hazem N; Nounou, Mohamed; Datta, Aniruddha; Dougherty, Edward R

    2011-05-01

    Recent years have witnessed extensive research activity in modeling biological phenomena as well as in developing intervention strategies for such phenomena. S-systems, which offer a good compromise between accuracy and mathematical flexibility, are a promising framework for modeling the dynamical behavior of biological phenomena. In this paper, two different intervention strategies, namely direct and indirect, are proposed for the S-system model. In the indirect approach, the prespecified desired values for the target variables are used to compute the reference values for the control inputs, and two control algorithms, namely simple sampled-data control and model predictive control (MPC), are developed for transferring the control variables from their initial values to the computed reference ones. In the direct approach, a MPC algorithm is developed that directly guides the target variables to their desired values. The proposed intervention strategies are applied to the glycolytic-glycogenolytic pathway and the simulation results presented demonstrate the effectiveness of the proposed schemes. PMID:21172748

  10. Atmospheric pollution in Lisbon urban atmosphere

    NASA Astrophysics Data System (ADS)

    Oliveira, C.

    2009-04-01

    Lisbon is the capital city of Portugal with about 565,000 residents in 2008 and a population density of 6,600 inhabitants per square kilometre. Like several other major metropolis, the town is surrounded by satellite cities, forming together a region known as "Lisbon Metropolitan Area" with about 3 million inhabitants, a quarter of the overall Portuguese population. Besides their local residents, it is estimated that more than one million citizens come into the Lisbon area every day from the outskirts, leading to elevated traffic densities and intense traffic jams, with important consequences on air pollution levels and obvious negative impacts on human health. Airborne particulate matter limit values are frequently exceeded, making urgent the existence of consistent programs to monitor and help taking measures to control them. Within the Portuguese project PAHLIS (Polycyclic Aromatic Hydrocarbons Contamination in Lisbon Urban Atmosphere) financed by the Portuguese Science Foundation ("Fundação para a Ciência e a Tecnologia"), an aerosol and vapour phase sampling program is being implemented in the city of Lisbon at two selected contrasting zones, namely a typically busy area with intense road traffic and frequent exceedences of the particulate matter standard for the maximum allowable concentration, and a residential quieter area, thus with a cleaner atmosphere characterised as an urban background site. An one month-long sampling campaign was performed during the summer of 2008, where particulate matter was collected in two fractions (coarse 2.5µmatmospheric pollutants in Portugal and present, for the first time, systematic data of PAHs levels in Lisbon. Acknowledgement: This work was performed under Project PAHLIS (PTDC/AMB/65699/2006) financed by "Fundação para a Ciência e a Tecnologia". C. Oliveira thanks Project PAHLIS his scholarship.

  11. Numerical Simulation of Low Mach Number Fluid - Phenomena.

    NASA Astrophysics Data System (ADS)

    Reitsma, Scott H.

    A method for the numerical simulation of low Mach number (M) fluid-acoustic phenomena is developed. This computational fluid-acoustic (CFA) methodology is based upon a set of conservation equations, termed finite-compressible, derived from the unsteady Navier-Stokes equations. The finite-compressible and more familiar pseudo-compressible equations are compared. The impact of derivation assumptions are examined theoretically and through numerical experimentation. The error associated with these simplifications is shown to be of O(M) and proportional to the amplitude of unsteady phenomena. A computer code for the solution of the finite -compressible equations is developed from an existing pseudo -compressible code. Spatial and temporal discretization issues relevant in the context of near field fluid-acoustic simulations are discussed. The finite volume code employs a MUSCL based third order upwind biased flux difference splitting algorithm for the convective terms. An explicit, three stage, second order Runge-Kutta temporal integration is employed for time accurate simulations while an implicit, approximately factored time quadrature is available for steady state convergence acceleration. The CFA methodology is tested in a series of problems which examine the appropriateness of the governing equations, the exacerbation of spatial truncation errors and the degree of temporal accuracy. Characteristic based boundary conditions employing a spatial formulation are developed. An original non-reflective boundary condition based upon the generalization and extension of existing methods is derived and tested in a series of multi-dimensional problems including those involving viscous shear flows and propagating waves. The final numerical experiment is the simulation of boundary layer receptivity to acoustic disturbances. This represents the first simulation of receptivity at a surface inhomogeneity in which the acoustic phenomena is modeled using physically appropriate wavelengths. Required steady solution accuracy, convergence acceleration techniques, boundary condition/flow field interactions and the challenges of scale resolution are addressed. The computed results are in agreement with linear stability theory and experimental measurements. The overall conclusion is that this methodology, once optimized, represents a potentially valuable tool for studying the physics of fluid-acoustic phenomena including edgetone feedback, cavity resonance, transition phenomena and eventually turbulent flow noise generation.

  12. FOUDRE ET ATMOSPHERES EXPLOSIVES LIGHTNING AND EXPLOSIVES ATMOSPHERES

    E-print Network

    Paris-Sud XI, Université de

    97-36 FOUDRE ET ATMOSPHERES EXPLOSIVES LIGHTNING AND EXPLOSIVES ATMOSPHERES HALAMA S., 1NERIS l'utilisation de produits sensibles pouvant provoquer facilement des incendies et des explosions. C inflammables. Les atmospheres explosives gazeuses et poussiereuses ainsi que les conditions favorisant [eur

  13. Thermal imaging through the atmosphere: atmospheric MTF theory and verification

    Microsoft Academic Search

    Dan Sadot; G. Kitron; N. Kitron; Norman S. Kopeika

    1993-01-01

    Both active and passive atmospheric modulation transfer function (MTF) measurements carried out simultaneously in both thermal imaging atmospheric windows are presented. Results indicate rather significant angular spatial frequency dependence of the MTF, in contradiction to the conventional approach which assumes contrast transfer is atmospheric transmission only. A theoretical explanation is discussed based upon aerosol forward scattering and absorption effects which

  14. Atmospheric Pollution Research 2 (2011) 283299 Atmospheric Pollution Research

    E-print Network

    2011-01-01

    ­latitude air­quality studies. These weak­dynamic conditions strongly limit vertical mixing of often­polluted air close to the ground with less polluted air at higher levels of the atmospheric Atmospheric Pollution Research 2 (2011) 283299 Atmospheric Pollution Research www

  15. The nitrogen cycle: Atmosphere interactions

    NASA Technical Reports Server (NTRS)

    Levine, J. S.

    1984-01-01

    Atmospheric interactions involving the nitrogen species are varied and complex. These interactions include photochemical reactions, initiated by the absorption of solar photons and chemical kinetic reactions, which involve both homogeneous (gas-to-gas reactions) and heterogeneous (gas-to-particle) reactions. Another important atmospheric interaction is the production of nitrogen oxides by atmospheric lightning. The nitrogen cycle strongly couples the biosphere and atmosphere. Many nitrogen species are produced by biogenic processes. Once in the atmosphere nitrogen oxides are photochemically and chemically transformed to nitrates, which are returned to the biosphere via precipitation, dry deposition and aerosols to close the biosphere-atmosphere nitrogen cycle. The sources, sinks and photochemistry/chemistry of the nitrogen species; atmospheric nitrogen species; souces and sinks of nitrous oxide; sources; sinks and photochemistry/chemistry of ammonia; seasonal variation of the vertical distribution of ammonia in the troposphere; surface and atmospheric sources of the nitrogen species, and seasonal variation of ground level ammonia are summarized.

  16. Joint Institute Marine and Atmospheric

    E-print Network

    Hawai'i at Manoa, University of

    Joint Institute for Marine and Atmospheric Research NATIONALOCEA NIC AND ATMOSPHERIC ADMINISTRATION Contribution 00-328 #12;ii This research is funded by Cooperative Agreement Number NA67RJ0154 between the Joint

  17. Pluto's Atmosphere Does Not Collapse

    E-print Network

    Olkin, C B; Borncamp, D; Pickles, A; Sicardy, B; Assafin, M; Bianco, F B; Buie, M W; de Oliveira, A Dias; Gillon, M; French, R G; Gomes, A Ramos; Jehin, E; Morales, N; Opitom, C; Ortiz, J L; Maury, A; Norbury, M; Ribas, F B; Smith, R; Wasserman, L H; Young, E F; Zacharias, M; Zacharias, N

    2013-01-01

    Combining stellar occultation observations probing Pluto's atmosphere from 1988 to 2013 and models of energy balance between Pluto's surface and atmosphere, we conclude that Pluto's atmosphere does not collapse at any point in its 248-year orbit. The occultation results show an increasing atmospheric pressure with time in the current epoch, a trend present only in models with a high thermal inertia and a permanent N2 ice cap at Pluto's north rotational pole.

  18. Multi-year observations of the tropical Atlantic atmosphere: Multidisciplinary applications of the NOAA Aerosols and Ocean

    E-print Network

    , attention is given to atmospheric soundings of ozone, temperature, water vapor, pressure, and wind obtained meteorological phenomena germane to the satellite missions in question, including dust and smoke outflows from Africa, the Saharan air layer (SAL), the distribution of tropical water vapor and tropical Atlantic ozone

  19. The Mars limited area model and simulations of atmospheric circulations for the Phoenix landing area and season of operation

    Microsoft Academic Search

    Janne Kauhanen; Tero Siili; Simo Järvenoja; Hannu Savijärvi

    2008-01-01

    The Mars limited area model (MLAM) has been used to simulate Martian northern polar atmospheric circulation phenomena during the planned season of the Phoenix Lander touching down on the surface (Ls ? 76°). Initial and boundary conditions are from Thermal Emission Spectrometer observations assimilated via the United Kingdom Mars General Circulation Model. The higher-resolution north pole-centric nestings (grid lengths about

  20. 78 FR 8202 - Meeting of the Joint ACRS Subcommittees on Thermal Hydraulic Phenomena and Materials, Metallurgy...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-05

    ...ACRS) Meeting of the Joint ACRS Subcommittees on Thermal Hydraulic Phenomena and Materials, Metallurgy and Reactor Fuels; Notice of Meeting The Joint ACRS Subcommittees on Thermal Hydraulic Phenomena and Materials, Metallurgy and Reactor...

  1. Atmospheric pressure plasmas: A review

    Microsoft Academic Search

    Claire Tendero; Christelle Tixier; Pascal Tristant; Jean Desmaison; Philippe Leprince

    2006-01-01

    This article attempts to give an overview of atmospheric plasma sources and their applications. The aim is to introduce, in a first part, the main scientific background concerning plasmas as well as the different atmospheric plasma sources (description, working principle). The second part focuses on the various applications of the atmospheric plasma technologies, mainly in the field of surface treatments.Thus

  2. How life affects the atmosphere

    NASA Technical Reports Server (NTRS)

    Walker, J. C.

    1984-01-01

    The impact of life on the atmosphere is examined through a discussion of the budgets of important atmospheric constituents and the processes that control their concentrations. Life profoundly influences oxygen and a number of minor atmospheric constituents, but many important gases, including those with the greatest effect on global climate, appear to be little altered by biological processes, at least in the steady state.

  3. Spectral Imaging through the Atmosphere

    E-print Network

    Zanibbi, Richard

    Spectral Imaging through the Atmosphere Steven Adler-Golden Leader, Passive Sensing Group Spectral materials and objects in the scene, but only if the effects of the intervening atmosphere can be modeled and development of atmospheric radiation transport codes for the remote sensing community, simulation of three

  4. Low Frequency Atmospheric Acoustic Propagation

    Microsoft Academic Search

    Patricia Anne Miller Oakley

    1989-01-01

    In this thesis we shall study several interesting problems in atmospheric acoustic propagation. Two approaches will be used, both normal mode and ray analyses. We first look at normal mode solutions to the equations of atmospheric acoustics. We obtain the Green's function for a two layered isothermal atmosphere and apply our results to some scattering problems. Transmission and reflection coefficients

  5. How Mars lost its atmosphere

    Microsoft Academic Search

    Kevin Zahnle

    1992-01-01

    There is a widespread suspicion that Mars thin atmosphere is in some way attributable to the planet's size. Another possibility is that the atmosphere was never degassed or outgassed in the first place. I prefer escape. Hydrodynamic escape (vigorous thermal escape) and impact erosion (expulsion of atmosphere by impacts) are two processes that should have been operative early. Although in

  6. Parametric analysis of atmospheric processes

    Microsoft Academic Search

    M. Elshamy

    1993-01-01

    The different phases of the space shuttle mission operations and systems analyses are influenced by several random perturbations due to the dynamics of atmospheric processes. From the mission planning point of view, there are few atmospheric conditions of interest, such as thunderstorm, precipitation, cloud ceiling, peak surface wind speed, etc. These atmospheric conditions, called parameters, are actually constraints on the

  7. Comparative Understanding of Planetary Atmospheres

    Microsoft Academic Search

    D. L. Huestis; S. K. Atreya; S. J. Bolton; S. W. Bougher; A. Coustenis; S. G. Edgington; A. J. Friedson; C. A. Griffith; S. L. Guberman; H. B. Hammel; J. I. Lunine; M. Mendillo; J. Moses; I. Mueller-Wodarg; G. S. Orton; K. A. Rages; T. G. Slanger; D. V. Titov; R. Yelle

    2001-01-01

    Observing, characterizing, and understanding planetary atmospheres are key components of solar system exploration. A planet's atmosphere is the interface between the surface and external energy and mass sources. Understanding how atmospheres are formed, evolve, and respond to perturbations is essential for addressing the long-range science objectives of identifying the conditions that are favorable for producing and supporting biological activity, managing

  8. Global atmospheric moisture variability

    NASA Technical Reports Server (NTRS)

    Robertson, Franklin R.; James, Bonnie F.; Chi, Kay; Huang, Huo-Jin

    1989-01-01

    Research efforts during FY-88 have focused on completion of several projects relating to analysis of FGGE data during SOP-1 and on expanded studies of global atmospheric moisture. In particular, a revised paper on the relationship between diabatic heating and baroclinicity in the South Pacific Convergence Zone (SPCZ) was submitted. A summary of completed studies on diagnostic convective parameterization was presented at the Satellite Meteorology and Oceanography Convergence last February. These investigations of diabatic heating in the SPCZ have demonstrated the requirement for a more quantitative description of atmospheric moisture. As a result, efforts were directed toward use of passive remote microwave measurements from the Nimbus-7 SMMR and the DOD's Special Sensor Microwave Imager (SSMI/I) as critical sources of moisture data. Activities this year are summarized.

  9. Atmospheric Release Advisory Capability

    SciTech Connect

    Dickerson, M.H.; Gudiksen, P.H.; Sullivan, T.J.

    1983-02-01

    The Atmospheric Release Advisory Capability (ARAC) project is a Department of Energy (DOE) sponsored real-time emergency response service available for use by both federal and state agencies in case of a potential or actual atmospheric release of nuclear material. The project, initiated in 1972, is currently evolving from the research and development phase to full operation. Plans are underway to expand the existing capability to continuous operation by 1984 and to establish a National ARAC Center (NARAC) by 1988. This report describes the ARAC system, its utilization during the past two years, and plans for its expansion during the next five to six years. An integral part of this expansion is due to a very important and crucial effort sponsored by the Defense Nuclear Agency to extend the ARAC service to approximately 45 Department of Defense (DOD) sites throughout the continental US over the next three years.

  10. Durban atmospheric lidar program

    NASA Astrophysics Data System (ADS)

    Moorgawa, Ashokabose; Michaelis, Max M.; Diab, R. D.; Anderson, J.; Kuppen, M.; Prause, A. R.; McKenzie, Edric; Porteneuve, Jacques; Leveau, Jean; Bencherif, Hassan; Morel, B.; Cunningham, P. F.

    2000-08-01

    A brief description and use of two LIDAR (Acronym for LIght Detection And Ranging) systems in the measurements of atmospheric aerosols and vertical temperature profiles above Durban are presented. Early local aerosol profiles for low medium and high altitudes from the old LIDAR are shown. With the recent installation of the new LIDAR, vertical temperature measurements in the troposphere and stratosphere are made possible. A first validation of the new LIDAR has been carried out showing atmospheric wave activity above the Southern African continent for the first time. It is envisaged in the future to correlate the results obtained with the new LIDAR, especially for the low altitude, with those of the old LIDAR. Plans are also going ahead to implement an additional channel on the new LIDAR which will measure ozone concentration in the troposphere.

  11. The Earth's Atmosphere

    NSDL National Science Digital Library

    This section of the Windows to the Universe web site provides information and images about Earth's atmosphere including detailed information about the layers of Earth's atmosphere, the greenhouse effect, and weather. Windows to the Universe is a user-friendly learning system pertaining to the Earth and Space sciences. The objective of this project is to develop an innovative and engaging web site that spans the Earth and Space sciences and includes a rich array of documents, including images, movies, animations, and data sets that explore the Earth and Space sciences and the historical and cultural ties between science, exploration and the human experience. Links at the top of each page allow users to navigate between beginner, intermediate and advanced levels. The content is also available in Spanish.

  12. Measurements of atmospheric turbulence

    NASA Technical Reports Server (NTRS)

    Murrow, Harold N.

    1987-01-01

    Various types of atmospheric turbulence measurements are addressed for the purpose of stimulating discussion relative to available data. An outline of these various types of measurements are discussed. Some specific results of detailed characterization studies made at NASA Langley are emphasized. The most recent reports on statistics of turbulence encounters for various types of aircraft operations are summarized. Special severe encounter studies and reference to remote sensing are also included. Wind shear is considered to be a special topic and is not covered.

  13. Atmospheres around Neutron Stars

    NASA Astrophysics Data System (ADS)

    Fryer, Chris L.; Benz, Willy

    1994-12-01

    Interest in the behavior of atmospheres around neutron stars has grown astronomically in the past few years. Some of this interest arrived in the wake of the explosion of Supernova 1987A and its elusive remnant; spawning renewed interest in a method to insure material ``fall-back'' onto the adolescent neutron star in an effort to transform it into a silent black hole. However, the bulk of the activity with atmospheres around neutron stars is concentrated in stellar models with neutron star, rather than white dwarf, cores; otherwise known as Thorne-Zytkow objects. First a mere seed in the imagination of theorists, Thorne-Zytkow objects have grown into an observational reality with an ever-increasing list of formation scenarios and observational prospects. Unfortunately, the analytic work of Chevalier on supernova fall-back implies that, except for a few cases, the stellar simulations of Thorne-Zytkow objects are missing an important aspect of physics: neutrinos. Neutrino cooling removes the pressure support of these atmospheres, allowing accretion beyond the canonical Eddington rate for these objects. We present here the results of detailed hydrodynamical simulations in one and two dimensions with the additional physical effects of neutrinos, advanced equations of state, and relativity over a range of parameters for our atmosphere including entropy and chemical composition as well as a range in the neutron star size. In agreement with Chevalier, we find, under the current list of formation scenarios, that the creature envisioned by Thorne and Zytkow will not survive the enormous appetite of a neutron star. However, neutrino heating (a physical effect not considered in Chevalier's analysis) can play an important role in creating instabilities in some formation schemes, leading to an expulsion of matter rather than rapid accretion. By placing scrutiny upon the formation methods, we can determine the observational prospects for each.

  14. Atmospheric autorotating imaging device

    NASA Technical Reports Server (NTRS)

    Burke, James D. (Inventor)

    1989-01-01

    An imaging device that automatically rotates upon descent through an atmosphere provides an onboard image detector a sweeping panoramic scan as it descends. No moving parts or propulsion system are required. The location, angle and pitch of the winged structure, together with its inertia properties, passively induces rotation. The angled location of the image detector takes advantage of the resulting rotation. Data generated by the image detector may be transmitted to a remote receiver or, alternatively, stored for subsequent recovery.

  15. SMEAT atmosphere trace contaminants.

    NASA Technical Reports Server (NTRS)

    Schornick, J. L.; Heinrich, C. T.; Garcia, G. S., Jr.; Verostko, C. E.

    1973-01-01

    The atmosphere trace contaminant analysis support provided for the Skylab Medical Experiments Altitude Test (SMEAT) which was conducted from July 26 through September 20, 1972, at the JSC Crew Systems Division facility is discussed. Sample acquisition techniques and analytical instrumentation methodology utilized for identification and quantification of the trace contaminants are described. Emphasis is placed on the contaminants found, their occurrence patterns, and possible sources.

  16. Atmospheric Pressure Glow Discharges

    SciTech Connect

    Graham, W. G.; Nersisyan, G. [International Research Centre for Experimental Physics, Queens University Belfast, BT7 1NN, Northern Ireland (United Kingdom)

    2006-12-01

    Their relative engineering simplicity, plasma uniformity and chemistry make Atmospheric Pressure Glow Discharges (APGD) very attractive for plasma processing applications. Here some of the basic characteristics of glow discharges are introduced. The basic dielectric barrier discharge and how it can be operated in a uniform glow rather filamentary mode is described. Electrical and laser-based measurements that throw light on the underlying physics of APGDs are presented, along with a model which seeks to explore the plasma chemistry of these discharges.

  17. Atmospheric prediction model survey

    NASA Technical Reports Server (NTRS)

    Wellck, R. E.

    1976-01-01

    As part of the SEASAT Satellite program of NASA, a survey of representative primitive equation atmospheric prediction models that exist in the world today was written for the Jet Propulsion Laboratory. Seventeen models developed by eleven different operational and research centers throughout the world are included in the survey. The surveys are tutorial in nature describing the features of the various models in a systematic manner.

  18. Discovering Pluto's atmosphere

    SciTech Connect

    Beatty, J.K.; Killian, A.

    1988-12-01

    Observations of the occultation of an obscure 12th-magnitude star in eastern Virgo by Pluto on June 9, 1988 are discussed. The occultation was observed by astronomers aboard NASA's Kuiper Airborne Observatory flying over the Pacific. The prediction of the occultation and the results of the observations are examined. The study demonstrated that Pluto has a thin atmosphere and that its diameter is about two-thirds that of the moon.

  19. Atmospheric Structure and Composition

    Microsoft Academic Search

    Darrell F. Strobel; Sushil K. Atreya; Bruno Bézard; Francesca Ferri; F. Michael Flasar; Marcello Fulchignoni; Emmanuel Lellouch; Ingo Müller-Wodarg

    2009-01-01

    Titan's atmosphere is predominantly N 2 with CH 4 the next most abundant molecule. It has a mole fraction of 0.05 just above the surface decreasing to 0.014 in the strato- sphere. Above the homopause (~800-850 km), it increases to 0.12 at the exobase. The third abundant molecule is H 2 with a tropospheric mole fraction of 0.001 increasing to

  20. Sequestering Atmospheric Carbon Dioxide

    Microsoft Academic Search

    R. Lal

    2009-01-01

    The abrupt climate change, attributed to increase in atmospheric concentration of CO2 and other greenhouse gases, has necessitated identification of technological options to sequester CO2 into other long-lived pools. Other viable pools for C sequestration include geologic, oceanic, and the terrestrial. There is also a potential to convert CO2 into stable minerals. There are geoengineering techniques of CO2 capture and