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1

Efcient Rendering of Atmospheric Phenomena  

Microsoft Academic Search

Rendering of atmospheric bodies involves modeling the complex interaction of light throughout the highly scat- tering medium of water and air particles. Scattering by these particles creates many well-known atmospheric optical phenomena including rainbows, halos, the corona, and the glory. Unfortunately, most radiative transport approximations in computer graphics are ill-suited to render complex angularly dependent effects in the presence of

Kirk Riley; David S. Ebert; Martin Kraus; Jerry Tessendorf; Charles Hansen

2

Polar Phenomena in Outer Planet Atmospheres  

NASA Astrophysics Data System (ADS)

Infrared observations of the polar regions of the outer planets have revealed similarities to the Earth's atmosphere and some new phenomena. The most dominant force which is apparent in time-dependent studies of the poles is seasonal radiative forcing, which was detected in Saturn's stratosphere as early as 1973. For Saturn, Uranus and Neptune, planets with substantial obliquities, the seasonally dependent changes are predictable and can be used to constrain abundances of optically active gases and the rate of restoration by stratospheric circulation. In the case of Neptune, recent evidence shows that the heating is sufficient to allow a "leak" from the reservoir of methane in the deep atmosphere into the polar stratosphere. New thermal images of Uranus show that the winter pole of Uranus which has only recently emerged fully from darkness is colder than when it was in the middle of winter when Voyager 2 visited, confirming the substantial seasonal phase delay associated with radiative heating and cooling models. Even Jupiter with its 3-degree obliquity shows clear evidence for seasonal forcing of temperatures in the upper troposphere and stratosphere. The second most prominent characteristic of the resolvable polar temperature fields in Jupiter and Saturn is the formation of polar vortices. Jupiter's polar vortices are cold, similar to those detected in the terrestrial planets; they have sharp equatorward boundaries which are characterized by Rossby waves which rotate at the speed of the local zonal wind flow and are coincident with the similarly irregular boundaries of a polar haze, also known as "polar hoods". The cold vortex at Saturn's northern winter pole is muted, but Saturn also has a unique "warm polar vortex" in the south (late summer) pole which shows no apparent wave structure. Saturn's warm polar vortex has no counterpart in the Earth's atmosphere, where summer radiative warming simply dissipates the cold winter vortex. Saturn also possesses dynamically driven hot regions within 2 degrees of its poles where dynamics is driving relatively dry air downwards, causing adiabatic warming and clearing the atmosphere; this phenomenon also has no terrestrial counterpart. Jupiter's upper polar stratosphere is warmed in discrete local regions by Joule heating from energetic particles cascading into the neutral atmosphere. The northern auroral-related polar "hot spot" has a very predictable geometry, but an amplitude that is variable over time scales of months. On the other hand, the stratosphere 25-30 degrees from Neptune's pole shows signs of ephemeral hot spots which are more likely to related to dynamics. These phenomena provide a rich basis of constraints for global climate models which must, at least for Jupiter, be coupled with models of auroral energy transport.

Orton, G.; Fletcher, L.; Yanamandra-Fisher, P.; Leyrat, C.; Greathouse, T.; Parrish, P.; Encrenaz, T.; Simon-Miller, A.

2008-12-01

3

Ball Lightning and Atmospheric Light Phenomena: A Common Origin?  

Microsoft Academic Search

The paper proposes a common origin of atmospheric light phenomena, including ball lightning and higher atmospheric lightnings such as UFOs and light emissions of various shapes. The emission of light from seemingly localized objects is described as the end stage of an electromagnetic process involving conversion of electric energy from the original distributed form between clouds to a concentrated form

TORE WESSEL-BERG

4

Atmospheric waves as scaling, turbulent phenomena  

NASA Astrophysics Data System (ADS)

It is paradoxical that while atmospheric dynamics are highly nonlinear and turbulent that atmospheric waves are commonly modelled by linear or weakly nonlinear theories. We postulate that the laws governing atmospheric waves are on the contrary high Reynold's number (Re), emergent laws so that - in common with the emergent high Re turbulent laws - they are also constrained by scaling symmetries. We propose an effective turbulence - wave propagator which corresponds to a fractional and anisotropic extension of the classical wave equation propagator with dispersion relations similar to those of inertial gravity waves (and Kelvin waves) yet with an anomalous (fractional) order Hwav/2. Using geostationary IR radiances, we estimate the parameters finding that Hwav/2 ? 0.17 ± 0.04 (the classical value = 2).

Pinel, J.; Lovejoy, S.

2013-06-01

5

Single event phenomena in atmospheric neutron environments  

SciTech Connect

As integrated circuit technology achieves higher density through smaller feature sizes and as the airplane manufacturing industry integrates more sophisticated electronic components into the design of new aircraft, it has become increasingly important to evaluate the contribution of single event effects, primarily Single Event Upset (SEU), to the safety and reliability of commercial aircraft. In contrast to the effects of radiation on electronic systems in space applications for which protons and heavy ions are of major concern, in commercial aircraft applications the interactions of high energy neutrons are the dominant cause of single event effects. These high energy neutrons are produced by the interaction of solar and galactic cosmic rays, principally protons and heavy ions, in the upper atmosphere. This paper will describe 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 will be presented, as well as measurements of charge collection in silicon test structures as a function of neutron energy. These are the first laboratory SEE and charge collection measurements using a particle beam having a continuum energy spectrum and with a shape nearly identical to that observed during flight.

Gossett, C.A.; Hughlock, B.W.; Katoozi, M.; LaRue, G.S. (Boeing Defense and Space Group, Seattle, WA (United States)); Wender, S.A. (Los Alamos National Lab., NM (United States))

1993-12-01

6

Aerothermodynamic Phenomena and the Design of Atmospheric Hypersonic Airplanes.  

National Technical Information Service (NTIS)

The design problems of aerodynamic hypersonic airplanes and the aerodynamic tools such as wind tunnels and computation methods are reviewed simultaneously with their validation problems. Aerodynamic phenomena such as viscosity, heat loads, heat transfer a...

E. H. Hirschel

1990-01-01

7

Elementary processes in prebreakdown phenomena in the atmosphere  

Microsoft Academic Search

The effect of negative oxygen ion destruction upon breakdown conditions in atmospheric air is analyzed. It is shown that ozone accumulation due to plasmochemical reactions occurring in ionized air produces a reduction in the breakdown voltage, related to negative O- ion destruction upon collision with ozone molecules under realistic conditions. A relationship is derived for electric field breakdown intensity and

A. V. Eletskii; B. M. Smirnov

1992-01-01

8

Wave phenomena comparison between Mars and Titan upper atmospheres  

NASA Astrophysics Data System (ADS)

We will examine the presence of waves in the neutral atmospheres of two terrestrial bodies: Mars and Titan. We will examine the aerobraking datasets from both the Mars Global Surveyor (MGS) and Mars Odyssey (ODY) missions, analyzing the neutral densities to characterize the planetary tides and/or smaller-scale internal gravity waves present in the data. While several studies have examined these features before at Mars (e.g., Forbes et al. [2002] and Fritts and Tolson [2006]), we will be focusing on examining whether or not the wave features observed in the thermosphere could be explained primarily with planetary tides, as posted recently in Klienbohl et al. [2013]. In addition to this, we will also examine the neutral densities obtained by the Cassini Ion-Neutral Mass Spectrometer (INMS) in order to determine if planetary tides can explain the numerous wave-like features that have been interpreted as gravity waves propagating vertically (cf., Mueller-Wodarg et al. [2008], Cui et al. [2013], and Snowden et al. [2013]).

Elrod, Meredith K.; Bell, J. M.

2013-10-01

9

Feedbacks between Hydrological Processes in Tropical South America and Large-Scale Ocean-Atmospheric Phenomena  

Microsoft Academic Search

The hydroclimatology of tropical South America is strongly coupled to low-frequency large-scale oceanicand atmospheric phenomena occurring over the Pacific and the Atlantic Oceans. In particular, El Niño-SouthernOscillation (ENSO) affects climatic and hydrologic conditions on timescales ranging from seasons to decades.With some regional differences in timing and amplitude, tropical South America exhibits negative rainfall andstreamflow anomalies in association with the low-warm

Germán Poveda; Oscar J. Mesa

1997-01-01

10

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

NASA Astrophysics Data System (ADS)

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 the emanation of gases in seismo-active regions, considers biological and geochemical processes. A lot of work was performed to analyse electromagnetic phenomena occurring before earthquakes. The propagation of infrasound and seismo-gravity waves was investigated. Characteristic parameters of the atmosphere, for instance the foF2-, foE-, and fbEs-frequencies, were analysed, and Es-spread and F-spread on the ionogrammes of vertical sounding stations were studied. Further, also a lot of models appeared explaining different pre-earthquake phenomena, but unfortunately not all phenomena observed under special conditions. Thus here, various possible earthquake precursors are reviewed. It is discussed how different precursors might be connected. Special attention is payed on contributions by the authors to develop two mechanisms of the generation of electric field variations before earthquakes, to describe non-equilibrium thermodynamic effects, and to explain excitations of plasma turbulence before earthquakes at different altitudes. Also some first active experiments to predict earthquakes are shortly mentioned. It is concluded that only the simultaneous analysis of various earthquake precursors and the simultaneous application of different active methods of prediction using earth-based, atmospheric and satellite methods - but also further-developed 'traditional' seismic methods, will help to solve the earthquake-prediction problem.

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

2010-05-01

11

PROPAGATING WAVE PHENOMENA DETECTED IN OBSERVATIONS AND SIMULATIONS OF THE LOWER SOLAR ATMOSPHERE  

SciTech Connect

We present high-cadence observations and simulations of the solar photosphere, obtained using the Rapid Oscillations in the Solar Atmosphere imaging system and the MuRAM magnetohydrodynamic (MHD) code, respectively. Each data set demonstrates a wealth of magnetoacoustic oscillatory behavior, visible as periodic intensity fluctuations with periods in the range 110-600 s. Almost no propagating waves with periods less than 140 s and 110 s are detected in the observational and simulated data sets, respectively. High concentrations of power are found in highly magnetized regions, such as magnetic bright points and intergranular lanes. Radiative diagnostics of the photospheric simulations replicate our observational results, confirming that the current breed of MHD simulations are able to accurately represent the lower solar atmosphere. All observed oscillations are generated as a result of naturally occurring magnetoconvective processes, with no specific input driver present. Using contribution functions extracted from our numerical simulations, we estimate minimum G-band and 4170 A continuum formation heights of 100 km and 25 km, respectively. Detected magnetoacoustic oscillations exhibit a dominant phase delay of -8 Degree-Sign between the G-band and 4170 A continuum observations, suggesting the presence of upwardly propagating waves. More than 73% of MBPs (73% from observations and 96% from simulations) display upwardly propagating wave phenomena, suggesting the abundant nature of oscillatory behavior detected higher in the solar atmosphere may be traced back to magnetoconvective processes occurring in the upper layers of the Sun's convection zone.

Jess, D. B.; Shelyag, S.; Mathioudakis, M.; Keys, P. H.; Keenan, F. P. [Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom); Christian, D. J., E-mail: d.jess@qub.ac.uk [Department of Physics and Astronomy, California State University Northridge, Northridge, CA 91330 (United States)

2012-02-20

12

Luminous Phenomena in the Atmosphere. A New Frontier of New Physics?  

NASA Astrophysics Data System (ADS)

A main geographic list of anomalous atmospheric light phenomena which are reocurring in several areas of the world is presented. In particular, the Norwegian light-phenomenon occurring in Hessdalen, a prototypical event of this class, is described in great detail. Results obtained in 1984 by the Norwegian scientific organization named 'Project Hessdalen' are discussed. Moreover, the present status and future projects of this organization are presented. It is also shown how the philosophy of research of Project Hessdalen can be adapted to the quantitative investigation of similar light phenomena in other parts of the world. Subsequently, the numerical analysis carried out by the author on the Project Hessdalen 1984 data is shown in detail. After illustrating the several physical theories which have been proposed so far to explain the light phenomenon, a strong emphasis is given on the quantitative definition of instrumental prerequisites and measurable physical parameters. A strategy aimed at defining the investigation methodology and instrumented monitoring in Italian areas of recurrence of the light phenomenon, is presented. An introduction is also given on the documented effects of interaction of the electromagnetic field produced by the light phenomenon with the brain electrical activity of people, by suggesting possible biophysical causes.

Teodorani, M.

1999-03-01

13

Simulation Study on Multi-Pulse Phenomena of Atmospheric Pressure Argon Dielectric Barrier Discharge  

NASA Astrophysics Data System (ADS)

In this paper, a one-dimensional discharge model is employed to study multi-pulse phenomena in Ar dielectric barrier discharge (DBD) under atmospheric pressure. The finite-element method is employed to solve the model. The influences of applied voltage amplitude and frequency as well as gas gap distance on the variation of multi discharge pulses are investigated and discussed. The simulation results show that, both the intensity of discharge current and the number of discharge pulses increase with the amplitude of applied voltage, and narrower gas gap is more favorable for the formation of multi pulses. It is revealed that Ar DBDs behave in glow discharge mode when the applied voltage and gas gap distance vary from 2 kV to 6 kV and from 1 mm to 3 mm, respectively. With the frequency decreasing from 250 Hz to 125 Hz, the intensity of discharge current weakens and the number of discharge pulses increases, and the discharges behave in the typical Townsend discharge mode.

Shao, Xianjun; Zhang, Guanjun; Kawada, Masatake; Ma, Yue; Li, Yaxi

2011-12-01

14

High Power Microwave Research, Atmospheric Plasma Phenomena, Ultra- Wideband Propagation and Generation.  

National Technical Information Service (NTIS)

The primary objectives of this effort were to investigate gas breakdown, plasma antennas, and laser induced plasmas in the atmosphere. The contractor investigated the electrical breakdown of different types of gas under very fast transient voltage excitat...

W. Prather D. W. Scholfield J. M. Gahi

2001-01-01

15

Phase-locking of lower atmosphere phenomena with space weather changes  

NASA Astrophysics Data System (ADS)

This work presents analysis of solar-terrestrial coupling using a new phase-locking technique, to detect characteristic signatures in solar variability expressed in atmospheric quantities. This method shows that, following changes in the heliosphere, phase-locked changes can be traced through energetic particles and into the lower atmosphere, specifically in the global electric circuit and cloud properties in the lower troposphere. The heliospherically-disturbed period of interest considered occurred during 2007-2009, when a characteristic 27 day variation in neutron monitor data was present, associated with a co-rotating interaction region (CIR). The neutron monitor data was itself phase locked to solar sector boundary changes. During the same period, phase-locked atmospheric electrical variations are apparent in the lower troposphere in the southern UK. Specifically, these include an increase in the vertical conduction current during increases in the neutron counter count rate, together with increases in energetic proton count rates. Suggestions have been made that extensive horizontal layer clouds can respond to conduction current density changes, due to the electrification expected at the base of layer clouds, which can influence droplet properties. We consider the evidence for this in cloud and surface meteorological measurements made at Lerwick Observatory, Shetland, by continued application of the phase-locked analysis method to the lower atmosphere data.

Nicoll, Keri; Harrison, R. Giles

2013-04-01

16

Natural extreme phenomena in the atmosphere and solar radiation increase on the Black Sea surface  

Microsoft Academic Search

This paper focuses on the processes leading to increase of the solar radiation, reaching the Black Sea surface. We have tried to analyze the correlation between sea surface temperature, clouds and ozone layer thickness above the Black Sea by using simultaneously data from the satellite system NOAA, TOMS and ground stations. The anomalous changes in the examined atmosphere and sea

A. Manev; K. I. Palazov; J. S. Jekov; G. H. Mardirossian; S. J. Stoyanov

2005-01-01

17

Investigation of chemical properties and transport phenomena associated with pollutants in the atmospheric boundary layer  

Microsoft Academic Search

Under the Clean Air Act, the U.S. Environmental Protection Agency is required to determine which air pollutants are harmful to human health, then regulate, monitor and establish criteria levels for these pollutants. To accomplish this and for scientific advancement, integration of knowledge from several disciplines is required including: engineering, atmospheric science, chemistry and public health. Recently, a shift has been

Heather A. Holmes

2010-01-01

18

Infrared characteristic radiation of water condensation and freezing in connection with atmospheric phenomena; Part 3: Experimental data  

NASA Astrophysics Data System (ADS)

This paper is the third one from the series of papers with the same titles published in this journal. The papers consider the infrared characteristic radiation (IRCR) during the first order phase transitions of water: crystallization, water vapor condensation, and water vapor deposition. Experimental results are analyzed in terms of their correspondence to the theoretical model. This model is based on the assertion that the particle's (atom, molecule, or cluster) transition from the higher energetic level in a metastable phase (vapor or liquid) to a lower level in a stable phase (liquid or crystal) produces an emission of one or more photons. The energy of these photons depends on the latent energy of the phase transition and the character of bonds formed by the particle in the new phase. For all investigated substances, this energy falls in the infrared range. Recorded in the atmosphere, numerous sources of the infrared radiation seem to be a result of crystallization, condensation and deposition of water during fog and cloud formation. The effect under investigation must play a very important role in atmospheric phenomena: it is one of the sources of Earth's cooling; formation of hailstorm clouds is accompanied by intensive IRCR that could be detected for process characterization and meteorological warnings. IRCR seems to be used for atmospheric energy accumulation and together with the wind, falling water, solar and geothermal energies makes available the fifth source of ecologically pure energy.

Tatartchenko, V.; Liu, Yifan; Chen, Wenyuan; Smirnov, P.

2012-09-01

19

Extensive Cloud Showers (ECS) - New High-Energy Phenomena Resulting from the Thunderstorm Atmospheres  

NASA Astrophysics Data System (ADS)

We report the phenomenon of the Extensive Cloud Showers (ECS) detected by the surface particle detectors at mountain altitudes in correlation with thunderstorms. Measured microsecond duration particle bursts are first direct evidence of the electron-photon avalanches in the thunderstorm atmospheres, reaching the mountain altitudes from low located thunderclouds. In the report we present analysis of these rare events including spatial distribution, density spectra and particle energy.

Chilingarian, A.; Hovsepyan, G.

2013-02-01

20

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

NASA Astrophysics Data System (ADS)

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.

Ha, Yan; Wang, Huijuan; Wang, Xiaofei

2012-01-01

21

Investigation of chemical properties and transport phenomena associated with pollutants in the atmospheric boundary layer  

NASA Astrophysics Data System (ADS)

Under the Clean Air Act, the U.S. Environmental Protection Agency is required to determine which air pollutants are harmful to human health, then regulate, monitor and establish criteria levels for these pollutants. To accomplish this and for scientific advancement, integration of knowledge from several disciplines is required including: engineering, atmospheric science, chemistry and public health. Recently, a shift has been made to establish interdisciplinary research groups to better understand the atmospheric processes that govern the transport of pollutants and chemical reactions of species in the atmospheric boundary layer (ABL). The primary reason for interdisciplinary collaboration is the need for atmospheric processes to be treated as a coupled system, and to design experiments that measure meteorological, chemical and physical variables simultaneously so forecasting models can be improved (i.e., meteorological and chemical process models). This dissertation focuses on integrating research disciplines to provide a more complete framework to study pollutants in the ABL. For example, chemical characterization of particulate matter (PM) and the physical processes governing PM distribution and mixing are combined to provide more comprehensive data for source apportionment. Data from three field experiments were utilized to study turbulence, meteorological and chemical parameters in the ABL. Two air quality field studies were conducted on the U.S./Mexico border. The first was located in Yuma, AZ to investigate the spatial and temporal variability of PM in an urban environment and relate chemical properties of ambient aerosols to physical findings. The second border air quality study was conducted in Nogales, Sonora, Mexico to investigate the relationship between indoor and outdoor air quality in order to better correlate cooking fuel types and home activities to elevated indoor PM concentrations. The final study was executed in southern Idaho and focused on comparing two gaseous dry deposition models to determine the fluxes of gaseous elemental mercury and reactive gaseous mercury using the measured concentrations and calculated deposition velocities for each species. Results indicate a large dependence on coupled physical, chemical and biological interactions for atmospheric processes, signifying the need for interdisciplinary collaboration.

Holmes, Heather A.

22

Numerical hydrodynamics of the jet phenomena in the solar atmosphere. I - Spicules  

NASA Astrophysics Data System (ADS)

Constant-cross section, one-dimensional and time-dependent hydrodynamic equations are solved numerically, in the realistic solar atmosphere extending from the photosphere to the corona, in a spicule model for which eruption occurs as a result of sudden pressure enhancement at the bright point located at the root of the spicule. The pressure enhancement generates a shock wave, which becomes stronger as it passes upward through the chromosphere and eventually collides with the chromosphere-corona interface. This interface represents something akin to a contact discontinuity, and the interface begins to move upward as a result of the process outlined. The matter following behind this interface is identified as the solar spicule.

Suematsu, Y.; Shibata, K.; Neshikawa, T.; Kitai, R.

1982-01-01

23

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

NASA Astrophysics Data System (ADS)

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.

Krueger, S. K.; Kochanski, A.

2009-12-01

24

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

NASA Astrophysics Data System (ADS)

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.

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

2009-05-01

25

Simulation of ENSO-like phenomena with a low-resolution coupled GCM of the global ocean and atmosphere  

SciTech Connect

A 140-year simulation of the ocean-atmosphere climate system has been performed by the GFDL Climate Dynamics Project using a low-resolution coupled general circulation model (GCM). The model was subjected to annually averaged insolation throughout the integration. This coupled system exhibits well-defined fluctuations in the tropical Pacific, with a preferred time scale of 3-4 years. The characteristics of these recurrent anomalies were examined by applying an extended empirical orthogonal function (EEOF) analysis to selected model variables. These results indicate that the simulated oscillations are accompanied by coherent changes in the atmospheric and oceanic circulation. The spatial patterns associated with the leading EEOF mode indicate that SST anomalies make their first appearance off the Peru-Ecuador coast and then migrate steadily westward, with an average transit time of 12-15 months. The arrival and eventual decay of SST fluctuations in the western Pacific is typically followed by the initiation of anomalies of the opposite polarity along the American coasts. The space-time evolution of various meteorological and oceanographic signals exhibits well-defined phase relationships with the SST perturbations. Some aspects of the model behavior during these warm and cold episodes are reminiscent of observed phenomena associated with the El Nino-Southern Oscillation (ENSO). Analysis of the climatological heat budget for the top ocean layer indicates a near balance between horizontal and vertical temperature advection by the time-mean flow, vertical diffusion, and heat input from the overlying atmosphere. The principal mechanisms associated with the simulated ENSO-like cycles were then studied by examining the local heat budget for the SST perturbations. The relative importance of various linear advective processes in the heat budget exhibits a notable dependence on geographical location and on the specific phase of the ENSO-like cycle.

Lau, Ngarcheung; Philander, S.G.H.; Nath, M.J. (Princeton Univ., NJ (United States))

1992-04-01

26

Scanning strategies for next generation weather radars. A study based on lifetimes of convective atmospheric phenomena hazardous to aviation  

Microsoft Academic Search

The lifetimes of significant features in typical storm phenomena were investigated and the results are expected to help in deciding the scan strategy of NEXRAD radars. In particular, the question of the adequacy of a 5 minute information update rate for NEXRAD in its aviation weather surveillance role was addressed. Two methods are used for the lifetime study: photo-interpretive and

P. R. Mahapatra; D. S. Zrnic

1982-01-01

27

Atmospherics in relation to source phenomena and radio wave propagation in the VHF, UHF, microwave and millimetre wave bands  

Microsoft Academic Search

Atmospherics originating from lightning flashes have been extensively studied by radio scientists for the last several decades, with a view to assessing and predicting the interfering effect on radio communication systems. Most of the earlier studies were confined to frequencies below about 30 MHz where ionospheric propagation can be exploited. The advent of satellite communication for a global coverage has,

A. K. Sen; M. K. Das Gupta

1987-01-01

28

Paranormal phenomena  

Microsoft Academic Search

Critical analysis is given of some paranormal phenomena events (UFO, healers, psychokinesis (telekinesis))reported in Moldova. It is argued that correct analysis of paranormal phenomena should be made in the framework of electromagnetism.

Alex Gaina

1996-01-01

29

Atmosphere  

NSDL National Science Digital Library

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

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

2003-01-01

30

Backdraft Phenomena.  

National Technical Information Service (NTIS)

The purpose of this project was to develop a fundamental physical understanding of backdraft phenomena. The research was divided into three phases: exploratory simulations, gravity current modeling, and quantitative backdraft experiments. The primary goal...

C. M. Fleischmann

1994-01-01

31

Atmospheric Optics  

NSDL National Science Digital Library

This collection, created and maintained by Harald Edens, contains photographs of many different atmospheric optical phenomena. Those phenomena include ice crystal halos, light scattering, and atmospheric refraction, among others. The pictures of each phenomenon are accompanied by a brief explanation of what causes it. Prints of the pictures can be purchased from the web site.

Edens, Harald

2008-04-30

32

TRANSIENT LUNAR PHENOMENA: REGULARITY AND REALITY  

Microsoft Academic Search

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

Arlin P. S. Crotts; Arlin P. S

2009-01-01

33

Atmospheric Processes  

Microsoft Academic Search

\\u000a Atmosphere is the most dynamic part of the terrestrial environment. It is driven by the energy received from the sun. Almost\\u000a all weather phenomena mentioned in Chapter 2 result from the differences in the amount of solar energy received and utilization\\u000a thereof. It is, therefore, necessary to understand as to how the energy from the sun is converted into heat

Pukh Raj Rakhecha; Vijay P. Singh

34

Ion exchange phenomena  

SciTech Connect

Ion exchange phenomena involve the population of readily exchangeable ions, the subset of adsorbed solutes that balance the intrinsic surface charge and can be readily replaced by major background electrolyte ions (Sposito, 2008). These phenomena have occupied a central place in soil chemistry research since Way (1850) first showed that potassium uptake by soils resulted in the release of an equal quantity of moles of charge of calcium and magnesium. Ion exchange phenomena are now routinely modeled in studies of soil formation (White et al., 2005), soil reclamation (Kopittke et al., 2006), soil fertilitization (Agbenin and Yakubu, 2006), colloidal dispersion/flocculation (Charlet and Tournassat, 2005), the mechanics of argillaceous media (Gajo and Loret, 2007), aquitard pore water chemistry (Tournassat et al., 2008), and groundwater (Timms and Hendry, 2007; McNab et al., 2009) and contaminant hydrology (Chatterjee et al., 2008; van Oploo et al., 2008; Serrano et al., 2009).

Bourg, I.C.; Sposito, G.

2011-05-01

35

Flow phenomena in turbomachines  

NASA Astrophysics Data System (ADS)

This report describes work carried out at the Gas Turbine Laboratory at MIT during the period 10/20/89 - 10/19/92, as part of our multi-investigator effort on basic unsteady flow phenomena in turbomachines. Within the overall project four separate tasks are specified. These are, in brief: (1) The Influence of Inlet Temperature Nonuniformities on Turbine Heat Transfer and Dynamics; (2) Assessment of Unsteady Losses in Stator/ Rotor Interactions; (3) Unsteady Phenomena and Flowfield instabilities in Multistage Axial Compressors; (4) Vortex Wake-Compressor Blade Interaction in Cascades - A New Rapid Method for Unsteady Separation and Vorticity Flux Calculations.

Creitzer, E. M.; Epstein, A. H.; Giles, M. B.; McCune, J. E.; Tan, C. S.

1993-01-01

36

Imaging of snapping phenomena  

PubMed Central

Snapping phenomena result from the sudden impingement between anatomical and/or heterotopical structures with subsequent abrupt movement and noise. Snaps are variously perceived by patients, from mild discomfort to significant pain requiring surgical management. Identifying the precise cause of snaps may be challenging when no abnormality is encountered on routinely performed static examinations. In this regard, dynamic imaging techniques have been developed over time, with various degrees of success. This review encompasses the main features of each imaging technique and proposes an overview of the main snapping phenomena in the musculoskeletal system.

Guillin, R; Marchand, A J; Roux, A; Niederberger, E; Duvauferrier, R

2012-01-01

37

COLLECTIVE PHENOMENA IN ACCELERATORS  

Microsoft Academic Search

Recent years have witnessed the development of accelerators of ever-larger current, both peak and average, as well as a proliferation of storage rings of ever-greater luminosity. Consequently, there is considerable interest in and growing concern with, the phenomena which limit beam currents and beam densities, namely, the collective modes of behavior of relativistic particle beams. Furthermore, it has been demonstrated

Sessler; Andrew M

1972-01-01

38

Solar cosmic ray phenomena  

Microsoft Academic Search

This review attempts to present an integrated view of the several types of solar cosmic ray phenomena. The relevant large and small scale properties of the interplanetary medium are first surveyed, and their use in the development of a quantitative understanding of the cosmic ray propagation processes summarised. Solar cosmic ray events, in general, are classified into two phenomenological categories:

K. G. McCracken; U. R. Rao

1970-01-01

39

Wave Phenomena Simulations  

NSDL National Science Digital Library

This resource contains interactive wave motion simulations for students in introductory physics classes. The various simulations model phenomena such as wave superposition, reflection, and refraction, as well as the interference of waves, the Doppler effect, the superposition of sine waves, and the various intensities of spherical waves.

Taylor, Barney

2003-10-10

40

Lunar transient phenomena  

NASA Astrophysics Data System (ADS)

Lunar transient phenomena (LTP) sightings are classified into five categories: brightenings, darkenings, reddish colorations, bluish colorations, and obscurations. There is evidence that the remaining LTP's are of lunar origin. A substantial number of sightings are independently confirmed. They have been recorded on film and spectrograms, as well as with photoelectric photometers and polarization equipment. It suggested that the LTP's may be gentle outgassings of less-than-volcanic proportions.

Cameron, W. S.

1991-03-01

41

The phenomena of inner experience  

Microsoft Academic Search

This study provides a survey of phenomena that present themselves during moments of naturally occurring inner experience. In our previous studies using Descriptive Experience Sampling (DES) we have discovered five frequently occurring phenomena—inner speech, inner seeing, unsymbolized thinking, feelings, and sensory awareness. Here we quantify the relative frequency of these phenomena. We used DES to describe 10 randomly identified moments

Christopher L. Heavey; Russell T. Hurlburt

2008-01-01

42

PREFACE Integrability and nonlinear phenomena Integrability and nonlinear phenomena  

NASA Astrophysics Data System (ADS)

Back in 1967, Clifford Gardner, John Greene, Martin Kruskal and Robert Miura published a seminal paper in Physical Review Letters which was to become a cornerstone in the theory of integrable systems. In 2006, the authors of this paper received the AMS Steele Prize. In this award the AMS pointed out that `In applications of mathematics, solitons and their descendants (kinks, anti-kinks, instantons, and breathers) have entered and changed such diverse fields as nonlinear optics, plasma physics, and ocean, atmospheric, and planetary sciences. Nonlinearity has undergone a revolution: from a nuisance to be eliminated, to a new tool to be exploited.' From this discovery the modern theory of integrability bloomed, leading scientists to a deep understanding of many nonlinear phenomena which is by no means reachable by perturbation methods or other previous tools from linear theories. Nonlinear phenomena appear everywhere in nature, their description and understanding is therefore of great interest both from the theoretical and applicative point of view. If a nonlinear phenomenon can be represented by an integrable system then we have at our disposal a variety of tools to achieve a better mathematical description of the phenomenon. This special issue is largely dedicated to investigations of nonlinear phenomena which are related to the concept of integrability, either involving integrable systems themselves or because they use techniques from the theory of integrability. The idea of this special issue originated during the 18th edition of the Nonlinear Evolution Equations and Dynamical Systems (NEEDS) workshop, held at Isola Rossa, Sardinia, Italy, 16-23 May 2009 (http://needs-conferences.net/2009/). The issue benefits from the occasion offered by the meeting, in particular by its mini-workshops programme, and contains invited review papers and contributed papers. It is worth pointing out that there was an open call for papers and all contributions were peer reviewed according to the standards of the journal. The selection of papers in this issue aims to bring together recent developments and findings, even though it consists of only a fraction of the impressive developments in recent years which have affected a broad range of fields, including the theory of special functions, quantum integrable systems, numerical analysis, cellular automata, representations of quantum groups, symmetries of difference equations, discrete geometry, among others. The special issue begins with four review papers: Integrable models in nonlinear optics and soliton solutions Degasperis [1] reviews integrable models in nonlinear optics. He presents a number of approximate models which are integrable and illustrates the links between the mathematical and applicative aspects of the theory of integrable dynamical systems. In particular he discusses the recent impact of boomeronic-type wave equations on applications arising in the context of the resonant interaction of three waves. Hamiltonian PDEs: deformations, integrability, solutions Dubrovin [2] presents classification results for systems of nonlinear Hamiltonian partial differential equations (PDEs) in one spatial dimension. In particular he uses a perturbative approach to the theory of integrability of these systems and discusses their solutions. He conjectures universality of the critical behaviour for the solutions, where the notion of universality refers to asymptotic independence of the structure of solutions (at the point of gradient catastrophe) from the choice of generic initial data as well as from the choice of a generic PDE. KP solitons in shallow water Kodama [3] presents a survey of recent studies on soliton solutions of the Kadomtsev-Petviashvili (KP) equation. A large variety of exact soliton solutions of the KP equation are presented and classified. The study includes numerical analysis of the stability of the found solution as well as numerical simulations of the initial value problems which indicate that a certain class of initial waves approach asymptotically these exact solutions

Gómez-Ullate, David; Lombardo, Sara; Mañas, Manuel; Mazzocco, Marta; Nijhoff, Frank; Sommacal, Matteo

2010-10-01

43

Transport phenomena in nanofluidics  

NASA Astrophysics Data System (ADS)

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 and practical achievements. This review focuses on the physical properties and operational mechanisms of the most common structures, such as nanometer-sized openings and nanowires in solution on a chip. Since the surface-to-volume ratio increases with miniaturization, this ratio is high in nanochannels, resulting in surface-charge-governed transport, which allows ion separation and is described by a comprehensive electrokinetic theory. The charge selectivity is most pronounced if the Debye screening length is comparable to the smallest dimension of the nanochannel cross section, leading to a predominantly counterion containing nanometer-sized aperture. These unique properties contribute to the charge-based partitioning of biomolecules at the microchannel-nanochannel interface. Additionally, at this free-energy barrier, size-based partitioning can be achieved when biomolecules and nanoconstrictions have similar dimensions. Furthermore, nanopores and nanowires are rooted in interesting physical concepts, and since these structures demonstrate sensitive, label-free, and real-time electrical detection of biomolecules, the technologies hold great promise for the life sciences. The purpose of this review is to describe physical mechanisms on the nanometer scale where new phenomena occur, in order to exploit these unique properties and realize integrated sample preparation and analysis systems.

Schoch, Reto B.; Han, Jongyoon; Renaud, Philippe

2008-07-01

44

Hysteresis phenomena in hydraulic measurement  

NASA Astrophysics Data System (ADS)

Hysteresis phenomena demonstrate the lag between the generation and the removal of some physical phenomena. This paper studies the hysteresis phenomena of the head-drop in a scaled model pump turbine using experiment test and CFD methods. These lag is induced by complicated flow patterns, which influenced the reliability of rotating machine. Keeping the same measurement procedure is concluded for the hydraulic machine measurement.

Ran, H. J.; Luo, X. W.; Chen, Y. L.; Xu, H. Y.; Farhat, M.

2012-11-01

45

Visualizational study on nucleate pool boiling phenomena  

NASA Astrophysics Data System (ADS)

It is important to visualize the intricate bubble behavior and the strong agitation of liquid near the heating surface to clarify the details concerning boiling mechanism. The visualization of nucleate pool boiling phenomena was confirmed by means of shadowgraphy using a still- camera (Nikon Photomic Camera) with the speed of 2000 frames per second. Illumination was provided by a photo spotlight or a stroboscope. The photographs show that the boiling phenomena and bubbles' behavior are varied for the heat flux of nucleate pool boiling based on the experiments. By considering the effect of revolving angle and the influence of a space between a tube and a tube, experiments have been carried out to investigate the nucleate pool boiling phenomena on horizontal stainless-steel-multi-tube in saturated distilled water. These experiments were performed for atmospheric pressure, for a stainless-tube diameter of 1.0 mm for a length of 80 mm, for a region of natural convection to nucleate boiling near burnout. From these results, photographs show that the successive motion and shape of bubbles during their process of detachment on the heating tube surface varied with increasing heat flux.

Kamei, Shuya

1993-01-01

46

Hypervelocity impact phenomena  

SciTech Connect

There is a need to determine the equations of state of materials in regimes of extreme high pressures, temperatures and strain rates that are not attainable on current two-stage light-gas guns. Understanding high-pressure material behavior is crucial to address the physical processes associated with a variety of hypervelocity impact events related to space sciences-orbital-debris impact, debris-shield designs, high-speed plasma propagation, and impact lethality applications. At very high impact velocities material properties will be dominated by phase-changes, such as melting or vaporization, which cannot be achieved at lower impact velocities. Development of well-controlled and repeatable hypervelocity launch capabilities is the first step necessary to improve our understanding of material behavior at extreme pressures and temperatures not currently available using conventional two-stage light-gas gun techniques. In this paper, techniques that have been used to extend both the launch capabilities of a two-stage light gas gun to 16 km/s, and their use to determine the material properties at pressures and temperature states higher than those ever obtained in the laboratory are summarized. The newly developed hypervelocity launcher (HVL) can launch intact (macroscopic dimensions) plates to 16 km/s. Time-resolved interferometric techniques have been used to determine shock-loading/release characteristics of materials impacted by such fliers as well as shock-induced vaporization phenomena in fully vaporized states. High-speed photography or radiography has been used to evaluate the debris propagation characteristics resulting from disc impact of thin bumper sheets at hypervelocities in excess of 10 km/s using the HVL. Examples of these experiments are provided in this paper.

Chhabildas, L.C.

1995-07-01

47

Ionospheric manifestations of wavelike disturbances in the atmosphere and ionosphere observed by radio tomography  

Microsoft Academic Search

Wavelike disturbances are quite often observed in the atmosphere and ionosphere These events can be caused by the influence from atmosphere and space by oscillations of the Earth surface and other phenomena In the atmosphere and ionosphere these wavelike phenomena appear as alternating areas of enhanced and depleted density in the atmosphere or electron concentration in the ionosphere In the

V. Kunitsyn; R. Ahmedov; E. Andreeva; M. Nazarenko; S. Suraev

2006-01-01

48

Eclipse Phenomena -- a Book Review.  

National Technical Information Service (NTIS)

The document is a review of the book Eclipse Phenomena in Astronomy by F. Link. The author of this book is a Czechoslovakian astronomer who has been associated with both Eastern and Western research in astronomy and space exploration.

G. F. Schilling

1969-01-01

49

Amateur Observations of Atmospheric Phenomena During the IGY  

NASA Astrophysics Data System (ADS)

The fiftieth anniversary of the International Geophysical Year (IGY) provides an opportunity to look back at a scientific program which is now almost forgotten. Many of the research fields of the IGY required large numbers of observers around the world, far more than could be provided by the staffs of established institutions and university research groups. It became necessary to recruit men and women from outside the normal scientific net, but with an interest in astronomy and the physics of the planet.

Schröder, Wilfried

2007-03-01

50

Application of Doppler radar and lidar to diagnose atmospheric phenomena  

Microsoft Academic Search

Observations and comparison of measurements of wind, waves, and turbulence, made with Doppler radar, lidar, and in-situ sensors, are presented. Applications to the detection of weather hazards to safe flight are discussed. A method to estimate rainfall with a polarization diversity Doppler radar is shown to be less sensitive to drop size distribution variations than commonly used Z-R relations. The

R. J. Doviak; M. Eilts; V. Mazur; M. Sachidananda; D. S. Zrnic

1986-01-01

51

Atmospheric propagation of laser beams  

NASA Astrophysics Data System (ADS)

A tutorial introduction to some of the more important phenomena that affect the propagation of laser beams through the atmosphere is presented, emphasizing those effects and parameters that control the peak irradiance on target. Atmospheric absorption and scattering, the effects of refractive index variations on beam propagation, laser beam propagation through vacuum and in an absorbing medium, and the propagation equation are addressed. For CW beams, the most significant phenomena are absorption and scattering by molecules and aerosols, as well as atmospheric turbulence and thermal blooming. The latter tends to dominate the longer wavelengths, while aerosol and turbulence effects are more important at the shorter wavelengths and result in larger variations in peak irradiance in the focal plane as atmospheric conditions change. Some of these effects can be overcome by using laser pulses rather than CW beams and/or adaptive optical techniques.

Weichel, H.

1985-12-01

52

Discovery potential for new phenomena  

SciTech Connect

The authors examine the ability of future facilities to discover and interpret non-supersymmetric new phenomena. The authors first explore explicit manifestations of new physics, including extended gauge sectors, leptoquarks, exotic fermions, and technicolor models. They then take a more general approach where new physics only reveals itself through the existence of effective interactions at lower energy scales.

Godfrey, S. [Carleton Univ., Ottawa, Ontario (Canada). Ottawa Carleton Inst. for Physics; Hewett, J.L. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Price, L.E. [Argonne National Lab., IL (United States). High Energy Physics Div.

1997-03-01

53

Electromechanical phenomena in semiconductor nanostructures  

Microsoft Academic Search

Electromechanical phenomena in semiconductors are still poorly studied from a fundamental and an applied science perspective, even though significant strides have been made in the last decade or so. Indeed, most current electromechanical devices are based on ferroelectric oxides. Yet, the importance of the effect in certain semiconductors is being increasingly recognized. For instance, the magnitude of the electric field

L. C. Lew Yan Voon; M. Willatzen

2011-01-01

54

Underwater explosions and cavitation phenomena  

Microsoft Academic Search

Some aspects of underwater explosions and cavitation phenomena have been studied by using a thermodynamic equation of state for water and a one-dimensional Lagrangian hydrocode. The study showed that surface cavitation is caused by the main blast wave and a bubble pulse from rebound of a release wave moving toward the center of the exploding bubble. Gravity has little effect

Kamegai

1979-01-01

55

Visualizing Chemical Phenomena in Microdroplets  

ERIC Educational Resources Information Center

Phenomena that occur in microdroplets are described to the undergraduate chemistry community. Droplets having a diameter in the micrometer range can have unique and interesting properties, which arise because of their small size and, especially, their high surface area-to-volume ratio. Students are generally unfamiliar with the characteristics of…

Lee, Sunghee; Wiener, Joseph

2011-01-01

56

Visualizing Chemical Phenomena in Microdroplets  

ERIC Educational Resources Information Center

|Phenomena that occur in microdroplets are described to the undergraduate chemistry community. Droplets having a diameter in the micrometer range can have unique and interesting properties, which arise because of their small size and, especially, their high surface area-to-volume ratio. Students are generally unfamiliar with the characteristics of…

Lee, Sunghee; Wiener, Joseph

2011-01-01

57

Dust phenomena in processing plasmas  

Microsoft Academic Search

Dust phenomena in processing plasmas are reviewed from the new viewpoint of birth of material in the plasma. The gas-phase growth of particles has been extensively studied for Si4 RF plasmas. The Si particles usually grow through three distinctive stages: an initial growth phase up to about 10 nm, whose size is between size ranges dominated by plasma properties and

Yukio Watanabe

1997-01-01

58

Magnetostrictive Phenomena in Magnetorheological Elastomers  

Microsoft Academic Search

A host of fascinating and useful magnetic phenomena are found in composites containing magnetizable particles in viscoelastic solids. Embedding magnetically soft iron particles in natural rubber produces a class of magnetostrictive composites sometimes termed magnetorheological (MR) elastomers. We have previously shown that these materials can exhibit viscoelastic moduli that increase substantially in an applied magnetic field. In this paper, we

J. M. Ginder; S. M. Clark; W. F. Schlotter; M. E. Nichols

2002-01-01

59

Virtual Physics Laboratory: Wave Phenomena  

NSDL National Science Digital Library

This site from Northwestern University discusses wave phenomena. The site features interactive applets of various wave types, including longitudinal, transverse, mixed, and sound waves. Also included are animations of superposition, beat frequencies, and the distinction between phase and group velocities, wave packets, and wave reflections.

Astronomy, The D.; University, Northwestern

60

Thermodynamic constraints on fluctuation phenomena  

Microsoft Academic Search

The relationships among reversible Carnot cycles, the absence of perpetual motion machines, and the existence of a nondecreasing globally unique entropy function form the starting point of many textbook presentations of the foundations of thermodynamics. However, the thermal fluctuation phenomena associated with statistical mechanics has been argued to restrict the domain of validity of this basis of the second law

O. J. E. Maroney

2009-01-01

61

Phenomena of flooding with condensation  

Microsoft Academic Search

The penetration of ECC water in the downcomer region of PWRs has recently been the subject of considerable research due to its importance in the safety analysis of a hypothetical LOCA. The difficulties in such analysis lie in the lack of understanding of the basic phenomena of counter-current two-phase flow, complicated also by the condensation effect and the geometry effect

Fan

1979-01-01

62

Theory of dynamic critical phenomena  

Microsoft Academic Search

An introductory review of the central ideas in the modern theory of dynamic critical phenomena is followed by a more detailed account of recent developments in the field. The concepts of the conventional theory, mode-coupling, scaling, universality, and the renormalization group are introduced and are illustrated in the context of a simple example-the phase separation of a symmetric binary fluid.

P. C. Hohenberg; B. I. Halperin

1977-01-01

63

Comparison of atmospheric losses in 850 nm and 1550 nm optical windows  

Microsoft Academic Search

Atmospheric phenomena such as scattering and turbulence can cause large variation in laser beam attenuation of free space optics systems. The paper deals with comparison of the atmospheric attenuation caused by both these phenomena and with comparison of the link availability affected by scattering at 850 nm and 1550 nm. The dispersive behavior of the atmosphere is modeled using the

Ales Prokes; Otakar Wilfert; Jiri Petrzela

2010-01-01

64

Jovian atmospheres  

SciTech Connect

A conference on the atmosphere of Jupiter produced papers in the areas of thermal and ortho-para hydrogen structure, clouds and chemistry, atmospheric structure, global dynamics, synoptic features and processes, atmospheric dynamics, and future spaceflight opportunities. A session on the atmospheres of Uranus and Neptune was included, and the atmosphere of Saturn was discussed in several papers.

Allison, M.; Travis, L.D.

1986-10-01

65

Transient Lunar Phenomena: Regularity and Reality  

NASA Astrophysics Data System (ADS)

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: ~50% of reports originate from near Aristarchus, ~16% from Plato, ~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 ~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.

Crotts, Arlin P. S.

2009-05-01

66

Review of anode phenomena in vacuum arcs  

SciTech Connect

This paper reviews anode phenomena in vacuum arcs. It discusses 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. 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 cathode; (2) a second low current mode that can occur if the electrode material is readily sputtered (a flux of sputtered atoms will be emitted by the anode); (3) a footpoint mode, characterized by the appearance of one or more luminous spots on the anode (footpoints are much cooler than the true anode spots present in the last two modes); (4) an anode spot mode in which one large or several small anode spots are present (such spots are very luminous, have a temperature near the atmospheric boiling point of the anode material, and are a copious source of vapor and ions); and (5) an intense arc mode where an anode spot is present, but accompanied by severe cathode erosion. The arc voltage is relatively low and quiet in the two low current modes and the intense arc mode. It is usually high and noisy in the footpoint mode, and it can be either in the anode spot mode. Anode erosion is low, indeed negative, in the two low current modes, and it is low to moderate in the footpoint mode. Severe anode erosion occurs in both the anode spot and intense arc modes.

Miller, H.C.

1984-06-04

67

TRANSIENT LUNAR PHENOMENA: REGULARITY AND REALITY  

SciTech Connect

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.

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

68

BOOK REVIEW: Plasma Kinetics in Atmospheric Gases  

Microsoft Academic Search

The book Plasma Kinetics in Atmospheric Gases is a worthwhile contribution to the basic phenomena in nitrogen, oxygen and other atmospheric gases. It contains basic introductory chapters on relaxation in translational, rotational (short) and vibrational (extensive) distribution and on the physics of electron excitation and electron distribution functions. In the latter, electron beam excitation (i.e. high electron energies) are included.

M. Capitelli; C. M. Ferreira; B. F. Gordiets; A. I. Osipov

2001-01-01

69

Statistical phenomena in particle beams  

SciTech Connect

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.

Bisognano, J.J.

1984-09-01

70

Cathodic phenomena in aluminum electrowinning  

NASA Astrophysics Data System (ADS)

Although aluminum is one of the world's highest production-volume primary metals, it is particularly costly to produce for a variety of factors, not the least of which are the expenses associated with electrolytic reduction. Based on the scale of global aluminum processing, even minor improvements in the electrowinning technology can result in significant savings of resources. Thus, from this perspective, the following reviews recent studies of cathodic phenomena in aluminum electrowinning.

Bouteillon, J.; Poignet, J. C.; Rameau, J. J.

1993-02-01

71

Thermodynamic constraints on fluctuation phenomena  

Microsoft Academic Search

The relationships between reversible Carnot cycles, the absence of perpetual\\u000amotion machines and the existence of a non-decreasing, globally unique entropy\\u000afunction forms the starting point of many textbook presentations of the\\u000afoundations of thermodynamics. However, the thermal fluctuation phenomena\\u000aassociated with statistical mechanics has been argued to restrict the domain of\\u000avalidity of this basis of the second law

O. J. E. Maroney

2009-01-01

72

New phenomena searches at CDF  

SciTech Connect

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.

Soha, Aron; /UC, Davis

2006-04-01

73

Noise Induced Phenomena: a Sampler  

NASA Astrophysics Data System (ADS)

Fluctuations or noise have played a changing role in the history of science. Historically, we can identify three views of noise. In the first, up to the end of the 19th century, noise was considered a nuisance to be avoided or eliminated. This is still the implication of the definition of the word noise in any standard dictionary. A second stage dates from the beginning of the 20th century, when it became clear from the study of fluctuations via Onsager relations and fluctuation-dissipation relations that one can obtain useful information about a physical system from its fluctuations. The third stage started about three decades ago, and is marked by the realization that noise can actually play a central role in inducing new phenomena. Examples where noise leads to organized behavior include stochastic resonance, noise-induced phase transitions, noise-induced pattern formation, and noise-induced transport. In this minicourse we sample some such noise-induced phenomena. While many of these fluctuation-induced phenomena involve temporal fluctuations, spatial fluctuations (disorder) can also play a similar organizing role. We briefly illustrate this scenario as well.

Wio, Horacio S.; Lindenberg, Katja

2003-03-01

74

The Local Structure of Atmospheric Turbulence and Its Effect on the Smagorinsky Model for Large Eddy Simulation  

Microsoft Academic Search

Phenomena such as large-scale shear, buoyancy, and the proximity to the ground surface significantly affect interactions among scales in atmospheric boundary layer turbulent flows. Hence, these phenomena impact parameters that enter subgrid-scale (SGS) parameterizations used in large eddy simulations (LES) of the atmospheric boundary layer. The effects of these phenomena upon SGS parameters have, to date, been studied mostly as

Marcelo Chamecki; Charles Meneveau; Marc B. Parlange

2007-01-01

75

Further Investigations of Oblique Hypervelocity Impact Phenomena.  

National Technical Information Service (NTIS)

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...

W. P. Schonberg

1988-01-01

76

Astronomical Phenomena for the Year 1991.  

National Technical Information Service (NTIS)

Astronomical phenomena for the year 1991 are presented in tabular form. Data is given on seasons, Moon phases, eclipses, occultations, perigee and apogee of the Moon, geocentric and heliocentric planetary phenomena, times of meridian passages of planets, ...

1990-01-01

77

Correlated randomness and switching phenomena  

NASA Astrophysics Data System (ADS)

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.

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

2010-08-01

78

Phenomena and Diosignes of Aratous  

NASA Astrophysics Data System (ADS)

Aratous (305-240B.C.) was a singular intellectual, writer and poet which engage himself to compose a very interesting astronomical poet, using the "Dactylous sixstage' style, the formal style of the ancient Greek Epic poetry. This astronomic poem of Aratous "Phenomena and Diosignes" became very favorite reading during the Alexandrine, the Romman and the Byzandin eras as well and had received many praises from significant poets and particularly from Hipparchous and from Theonas from Alexandria, an astronomer of 4rth century A.C.(in Greeks)

Avgoloupis, S. I.

2013-01-01

79

Emergent phenomena at oxide interfaces.  

PubMed

Recent technical advances in the atomic-scale synthesis of oxide heterostructures have provided a fertile new ground for creating novel states at their interfaces. Different symmetry constraints can be used to design structures exhibiting phenomena not found in the bulk constituents. A characteristic feature is the reconstruction of the charge, spin and orbital states at interfaces on the nanometre scale. Examples such as interface superconductivity, magneto-electric coupling, and the quantum Hall effect in oxide heterostructures are representative of the scientific and technological opportunities in this rapidly emerging field. PMID:22270825

Hwang, H Y; Iwasa, Y; Kawasaki, M; Keimer, B; Nagaosa, N; Tokura, Y

2012-01-24

80

Natural phenomena hazards, Hanford Site, Washington  

SciTech Connect

This document presents the natural phenomena hazard loads for use in implementing DOE Order 5480.28, Natural Phenomena Hazards Mitigation, and supports development of double-shell tank systems specifications at the Hanford Site in south-central Washington State. The natural phenomena covered are seismic, flood, wind, volcanic ash, lightning, snow, temperature, solar radiation, suspended sediment, and relative humidity.

Conrads, T.J.

1998-09-29

81

Multifractal phenomena in physics and chemistry  

Microsoft Academic Search

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

H. Eugene Stanley; Paul Meakin

1988-01-01

82

Uranium Pyrophoricity Phenomena and Prediction  

SciTech Connect

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.

DUNCAN, D.R.

2000-04-20

83

Thermoelectric Phenomena, Materials, and Applications  

NASA Astrophysics Data System (ADS)

Over the past 10-15 years, there have been significant advances in the scientific understanding as well as in the performance of thermoelectric (TE) materials. TE materials can be incorporated into power generation devices that are designed to convert waste heat into useful electrical energy. These TE materials can also be used in solid-state refrigeration devices for cooling applications. The conversion of waste heat into electrical energy will certainly play a role in our current challenge for alternative energy technologies to reduce our dependence on fossil fuels and to reduce greenhouse gas emissions. This article provides an overview of the various TE phenomena and discusses some of the primary TE materials that are currently being investigated. Several of the key parameters and terminology are defined and discussed along with an overview of some of the current and emerging technologies. The phonon glass-electron crystal approach to new TE materials for developing new materials is presented along with the role of solid-state crystal chemistry and the criteria for higher-performance TE materials. This article discusses TE phenomena, the selection criteria for higher-performance materials, and a few key materials.

Tritt, Terry M.

2011-08-01

84

Critical phenomena in magnetic nanowires.  

PubMed

In this paper we report the first experimental study of critical phenomena in case of magnetic nanowires of nickel near the ferromagnetic-paramagnetic transition from the electrical transport properties. Nickel nanowire arrays, prepared by potentiostatic electrodeposition of nickel inside pores of nanoporous anodic alumina template were well characterized by X-ray Diffraction, Transmission electron microscopy and Energy dispersive Spectroscopy. Precise electrical resistance measurement of the nanowire arrays of wire diameter 20 nm have been done in the temperature range between 300 K to 700 K. We see a drop in the Curie temperature as observed from the resistivity anomaly. We analyzed the resistance data near the critical region and extracted the critical exponent alpha directly from the resistance. We observed a decrease in the critical part of the resistivity including a decrease in the magnitude of the critical exponent alpha and severe modification in the correction to scaling. PMID:19928208

Kamalakar, M Venkata; Raychaudhuri, A K

2009-09-01

85

Relaxation phenomena in cryogenic electrolytes  

NASA Astrophysics Data System (ADS)

Proposed is a scenario for the development of observed relaxation phenomena in a cryogenic electrolyte with the structure of ``liquid hydrogen + injected ions.'' Ions of one sign are generated in the bulk of liquid hydrogen in the presence of external field E? by a stationary radioactive source of +/- ions at the bottom of a vessel. After accumulation near the free surface of the liquid with a finite density ns the ions can break its stability producing a pulse of ion current to the collector located above the liquid surface. The outlined process is periodically repeated. Its period contains information on the ion mobility and, which is most interesting, on dissociation (association) processes occurring in a system of charged particles placed in an external field. The cryogenic problem is a good model for dissociation in the presence of external field occurring in normal electrolytes without any external ion sources.

Shikin, V.; Chikina, I.; Nazin, S.

2013-06-01

86

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.

87

Emergent Phenomena at Oxide Interfaces  

SciTech Connect

Transition metal oxides (TMOs) are an ideal arena for the study of electronic correlations because the s-electrons of the transition metal ions are removed and transferred to oxygen ions, and hence the strongly correlated d-electrons determine their physical properties such as electrical transport, magnetism, optical response, thermal conductivity, and superconductivity. These electron correlations prohibit the double occupancy of metal sites and induce a local entanglement of charge, spin, and orbital degrees of freedom. This gives rise to a variety of phenomena, e.g., Mott insulators, various charge/spin/orbital orderings, metal-insulator transitions, multiferroics, and superconductivity. In recent years, there has been a burst of activity to manipulate these phenomena, as well as create new ones, using oxide heterostructures. Most fundamental to understanding the physical properties of TMOs is the concept of symmetry of the order parameter. As Landau recognized, the essence of phase transitions is the change of the symmetry. For example, ferromagnetic ordering breaks the rotational symmetry in spin space, i.e., the ordered phase has lower symmetry than the Hamiltonian of the system. There are three most important symmetries to be considered here. (i) Spatial inversion (I), defined as r {yields} -r. In the case of an insulator, breaking this symmetry can lead to spontaneous electric polarization, i.e. ferroelectricity, or pyroelectricity once the point group belongs to polar group symmetry. (ii) Time-reversal symmetry (T) defined as t {yields} -t. In quantum mechanics, the time-evolution of the wave-function {Psi} is given by the phase factor e{sup -iEt/{h_bar}} with E being the energy, and hence time-reversal basically corresponds to taking the complex conjugate of the wave-function. Also the spin, which is induced by the 'spinning' of the particle, is reversed by time-reversal. Broken T-symmetry is most naturally associated with magnetism, since the spin operator changes sign with T-operation. (iii) Gauge symmetry (G), which is associated with a change in the phase of the wave-function as {Psi} {yields} e{sup i{theta}}{Psi}. Gauge symmetry is connected to the law of charge conservation, and broken G-symmetry corresponds to superconductivity/superfluidity. To summarize, the interplay among these electronic degrees of freedom produces various forms of symmetry breaking patterns of I, T, and G, leading to novel emergent phenomena, which can appear only by the collective behavior of electrons and cannot be expected from individual electrons. Figure 1 shows this schematically by means of several representative phenomena. From this viewpoint, the interfaces of TMOs offer a unique and important laboratory because I is already broken by the structure itself, and the detailed form of broken I-symmetry can often be designed. Also, two-dimensionality usually enhances the effects of electron correlations by reducing their kinetic energy. These two features of oxide interfaces produce many novel effects and functions that cannot be attained in bulk form. Given that the electromagnetic responses are a major source of the physical properties of solids, and new gauge structures often appear in correlated electronic systems, we put 'emergent electromagnetism' at the center of Fig. 1.

Hwang, H.Y.

2012-02-16

88

In-vessel phenomena -- CORA  

SciTech Connect

Experiment-specific models have been employed since 1986 by Oak Ridge National Laboratory (ORNL) severe accident analysis programs for the purpose of boiling water reactor experimental planning and optimum interpretation of experimental results. The large integral tests performed to date, which start from an initial undamaged core state, have involved significantly different-from-prototypic boundary and experimental conditions because of either normal facility limitations or specific experimental constraints. These experiments (ACRR: DF-4, NRU: FLHT-6, and CORA) were designed to obtain specific phenomenological information such as the degradation and interaction of prototypic components and the effects on melt progression of control-blade materials and channel boxes. Applications of ORNL models specific to the KfK CORA-16 and CORA-17 experiments are discussed and significant findings from the experimental analyses such as the following are presented: applicability of available Zircaloy oxidation kinetics correlations; influence of cladding strain on Zircaloy oxidation; influence of spacer grids on the structural heatup; and the impact of treating the gaseous coolant as a gray interacting medium. The experiment-specific models supplement and support the systems-level accident analysis codes. They allow the analyst to accurately quantify the observed experimental phenomena and to compensate for the effect of known uncertainties. They provide a basis for the efficient development of new models for phenomena that are currently not modeled (such as material interactions). They can provide validated phenomenological models (from the results of the experiments) as candidates for incorporation in the systems-level whole-core'' codes.

Ott, L.J.; van Rij, W.I.

1991-01-01

89

Autistic phenomena in neurotic patients.  

PubMed

I have described a group of patients who are seemingly successful in their professional and social lives, and who seek analysis ostensibly for professional reasons or for minor difficulties in their relationship. However, sooner or later they reveal phenomena which are strikingly similar to those observed in so-called autistic children. These autistic phenomena are characterized by an almost impenetrable encapsulation of part of the personality, mute and implacable resistance to change, and a lack of real emotional contact either with themselves or the analyst. Progress of the analysis reveals an underlying intense fear of pain, and of death, disintegration or breakdown. These anxieties occur as a reaction to real or feared separation, especially when commitment to analysis deepens. In the case I have described in detail the patient used various projective processes to deflect painful emotions either into other people, including the analyst, or into their own bodies. As a consequence the various objects or organs of the body swell up and became suffused with rage as a result of having to contain the unwanted feelings. This process leads in turn to intense persecutory fears and a heightened sensitivity to the analyst's tone of voice and facial expression. It would seem that the initial hypersensitivity of part of the personality is such as to lead it to anticipate danger to such an extent that it expels feelings even before they reach awareness. The sooner the analyst realizes the existence of this hidden part of the patient the less the danger of the analysis becoming an endless and meaningless intellectual dialogue and the greater the possibilities of the patient achieving a relatively stable equilibrium. Although the analyst has to live through a great deal of anxiety with the patient I feel that ultimately the results make it worth while. PMID:7440079

Klien, S

1980-01-01

90

Turbulent phenomena in protein folding  

NASA Astrophysics Data System (ADS)

Protein folding and hydrodynamic turbulence are two long-standing challenges, in molecular biophysics and fluid dynamics, respectively. The theories of these phenomena have been developed independently and used different formalisms. Here we show that the protein folding flows can be surprisingly similar to turbulent fluid flows. Studying a benchmark model protein (an SH3 domain), we have found that the flows for the slow folding trajectories of the protein, in which a partly formed N- and C-terminal ? sheet hinders the RT loop from attaching to the protein core, have many properties of turbulent flows of a fluid. The flows are analyzed in a three-dimensional (3D) space of collective variables, which are the numbers of native contacts between the terminal ? strands, between the RT loop and the protein core, and the rest of the native contacts. We have found that the flows have fractal nature and are filled with 3D eddies; the latter contain strange attractors, at which the tracer flow paths behave as saddle trajectories. Two regions of the space increment have been observed, in which the flux variations are self-similar with the scaling exponent h=1/3, in surprising agreement with the Kolmogorov inertial range theory of turbulence. In one region, the cascade of protein rearrangements is directed from larger to smaller scales (net folding), and in the other, it is oppositely directed (net unfolding). Folding flows for the fast trajectories are essentially “laminar” and do not have the property of self-similarity. Based on the results of our study, we infer, and support this inference by simulations, that the origin of the similarity between the protein folding and turbulent motion of a fluid is in a cascade mechanism of structural transformations in the systems that underlies these phenomena.

Kalgin, Igor V.; Chekmarev, Sergei F.

2011-01-01

91

Atmospheric Effect  

Microsoft Academic Search

AN atmospheric effect, which is sometimes observed in England, displayed itself here in great beauty yesterday. The western sun had been cut off from us by an intervening ridge, while the upper atmosphere was still filled with his light. There was a good deal of opalescent haze in the atmosphere, which, had the sun shone upon it uniformly, would have

John Tyndall

1872-01-01

92

Electromechanical phenomena in semiconductor nanostructures  

NASA Astrophysics Data System (ADS)

Electromechanical phenomena in semiconductors are still poorly studied from a fundamental and an applied science perspective, even though significant strides have been made in the last decade or so. Indeed, most current electromechanical devices are based on ferroelectric oxides. Yet, the importance of the effect in certain semiconductors is being increasingly recognized. For instance, the magnitude of the electric field in an AlN/GaN nanostructure can reach 1-10 MV/cm. In fact, the basic functioning of an (0001) AlGaN/GaN high electron mobility transistor is due to the two-dimensional electron gas formed at the material interface by the polarization fields. The goal of this review is to inform the reader of some of the recent developments in the field for nanostructures and to point out still open questions. Examples of recent work that involves the piezoelectric and pyroelectric effects in semiconductors include: the study of the optoelectronic properties of III-nitrides quantum wells and dots, the current controversy regarding the importance of the nonlinear piezoelectric effect, energy harvesting using ZnO nanowires as a piezoelectric nanogenerator, the use of piezoelectric materials in surface acoustic wave devices, and the appropriateness of various models for analyzing electromechanical effects. Piezoelectric materials such as GaN and ZnO are gaining more and more importance for energy-related applications; examples include high-brightness light-emitting diodes for white lighting, high-electron mobility transistors, and nanogenerators. Indeed, it remains to be demonstrated whether these materials could be the ideal multifunctional materials. The solutions to these and other related problems will not only lead to a better understanding of the basic physics of these materials, but will validate new characterization tools, and advance the development of new and better devices. We will restrict ourselves to nanostructures in the current article even though the measurements and calculations of the bulk electromechanical coefficients remain challenging. Much of the literature has focused on InGaN/GaN, AlGaN/GaN, ZnMgO/ZnO, and ZnCdO/ZnO quantum wells, and InAs/GaAs and AlGaN/AlN quantum dots for their optoelectronic properties; and work on the bending of nanowires have been mostly for GaN and ZnO nanowires. We hope the present review article will stimulate further research into the field of electromechanical phenomena and help in the development of applications.

Lew Yan Voon, L. C.; Willatzen, M.

2011-02-01

93

Ordering Phenomena in Undercooled Alloys  

SciTech Connect

Much of the work performed under this grant was devoted to using modern ideas in kinetics to understand atom movements in metallic alloys far from thermodynamic equilibrium. Kinetics arguments were based explicitly on the vacancy mechanism for atom movements. The emphasis was on how individual atom movements are influenced by the local chemical environment of the moving atom, and how atom movements cause changes in the local chemical environments. The author formulated a kinetic master equation method to treat atom movements on a crystal lattice with a vacancy mechanism. Some of these analyses [3,10,16] are as detailed as any treatment of the statistical kinetics of atom movements in crystalline alloys. Three results came from this work. Chronologically they were (1) A recognition that tracking time dependencies is not necessarily the best way to study kinetic phenomena. If multiple order parameters can be measured in a material, the ''kinetic path'' through the space spanned by these order parameters maybe just as informative about the chemical factors that affect atom movements [2,3,5-7,9-11,14-16,18,19,21,23,24,26,36,37]. (2) Kinetic paths need not follow the steepest gradient of the free energy function (this should be well-known), and for alloys far from equilibrium the free energy function can be almost useless in describing kinetic behavior. This is why the third result surprised me. (3) In cluster approximations with multiple order parameters, saddle points are common features of free energy functions. Interestingly, kinetic processes stall or change time scale when the kinetic path approaches a state at a saddle point in the free energy function, even though these states exist far from thermodynamic equilibrium. The author calls such a state a ''pseudostable'' (falsely stable) state [6,21,26]. I have also studied these phenomena by more ''exact'' Monte Carlo simulations. The kinetic paths showed features similar to those found in analytical theories. The author found that a microstructure with interfaces arranged in space as a periodic minimal surface is a probably an alloy at a saddle point in its free energy function [21,26,37].

Fultz, Brent

1997-07-17

94

Data acquisition and simulation of natural phenomena  

Microsoft Academic Search

Virtual natural phenomena obtained through mathematical-physical modeling and simulation as well as graphics emulation can\\u000a meet the user’s requirements for sensory experiences to a certain extent but they can hardly have the same accurate physical\\u000a consistency as real natural phenomena. The technology for data acquisition and natural phenomena simulation can enable us\\u000a to obtain multi-dimensional and multi-modal data directly from

QinPing Zhao

2011-01-01

95

Interactive atmosphere  

NSDL National Science Digital Library

Where is ozone located in the atmosphere? This informational activity, part of an interactive laboratory series for grades 8-12, explores the changes in ozone concentration with altitude. Students are introduced to layers of the atmosphere and the amount of ozone found at each layer of the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. The activity also discusses why the addition of ozone to the atmosphere at different levels determines the temperatures of those levels. Students can move up and down to different layers of the atmosphere. A temperature scale is shown that runs from the surface of the Earth to the outer most reaches of the atmosphere. Copyright 2005 Eisenhower National Clearinghouse

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

2003-01-01

96

Atmospheric gases  

NSDL National Science Digital Library

Which gases make up the atmosphere? This activity page, part of an interactive laboratory series for grades 8-12, introduces students to the gaseous components of the atmosphere. Students explore the main gases of the atmosphere using a pop-up pie chart. Descriptions of the gases and their percentages in the atmosphere are provided. Students read about water vapor in the atmosphere, and an animation shows a simplified process of precipitation. A pop-up window explains the effects of dust on the atmosphere, and a photograph shows how large amounts of dust in the atmosphere create the reds and oranges displayed in sunsets. Finally, ozone is introduced to students as a necessary component of human life on Earth. Copyright 2005 Eisenhower National Clearinghouse

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

2003-01-01

97

A generalized version of the Rankine-Hugoniot relations including ionization, dissociation and related phenomena  

Microsoft Academic Search

For purposes of computing shocks in stellars atmospheres and winds we have developed a generalized version of the Rankine-Hugoniot relations including ionization, dissociation, radiation and related phenomena such as excitation, rotation and vibration of molecules. The new equations are given in analytical form. They are valid as long as the internal energy E, the total pressure P, and the first

H. Nieuwenhuijzen; C. de Jager; M. Cuntz; A. Lobel; L. Achmad

1993-01-01

98

Conductance phenomena in microcrystalline cellulose  

NASA Astrophysics Data System (ADS)

We have investigated the conduction phenomena in compacted tablets of cellulose with varying relative humidity (RH) with techniques such as Low Frequency Dielectric Spectroscopy (LFDS) and Transient Current (TC) at room temperature. Two exponential decaying regions in the transient current measurements indicate two ionic species contributing to the conduction mechanism. A high power-law exponent of 9 for the conductance with moisture content has been found. The mobility initially decreases with RH up to monolayer coverage, and further water vapor increases the mobility, indicating a blocking of available positions for the charge carrier ions. When the amount of water molecules present in the tablet increases one order of magnitude, the number of charge carriers increases 5-6 orders of magnitude, suggesting a transition from a power-law increase to a linear effective medium theory for the conduction. The charge carrier dependence on RH suggests that a percolating network of water molecules adsorbed to 6-OH units on the cellulose chain span through the sample. The conductivity mechanisms in cellulose are still not clear.

Nilsson, M.

2006-02-01

99

Understanding empathy and related phenomena.  

PubMed

Over a period of time, the author arrived at a few tentative postulates concerning empathy and related processes based on some of his experiences and observations. The central theme of these postulates is, firstly, that interpersonal interaction is an interaction of the personal-space fields. Secondly, empathy, therapeutic benefit, and the professional stress are all related to the same process of interpersonal interaction. This interaction takes place as an enmeshment of personal spaces of the interacting individuals, and involves transfer of a wide range of information in the affective, cognitive, and other areas. This is because the personal spaces have fieldlike qualities analogous to what Kurt Lewin described. Thus, such phenomena as empathy, therapeutic benefit, professional stress are all consequences of the same process. It is possible to substantiate these postulates by diverse evidences in the published literature. The natural consequences of such an interpersonal interaction are empathic understanding, transfer of mood states (like hope, distress or expectancy), affective states (like anxiety, sadness, anger or hostility), ideas, images and even attitudes and values, etc. This phenomenon of transfer can explain such processes as therapeutic benefit in individual and group settings, professional stress, shared delusions, and even experimenter bias. Whether one becomes aware of such transferred information or not depends upon the intent and sensitivity of the participants. PMID:10415993

Shamasundar, C

1999-01-01

100

WESF natural phenomena hazards survey  

SciTech Connect

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.

Wagenblast, G.R., Westinghouse Hanford

1996-07-01

101

Complex (dusty) plasmas-kinetic studies of strong coupling phenomena  

SciTech Connect

'Dusty plasmas' can be found almost everywhere-in the interstellar medium, in star and planet formation, in the solar system in the Earth's atmosphere, and in the laboratory. In astrophysical plasmas, the dust component accounts for only about 1% of the mass, nevertheless this component has a profound influence on the thermodynamics, the chemistry, and the dynamics. Important physical processes are charging, sputtering, cooling, light absorption, and radiation pressure, connecting electromagnetic forces to gravity. Surface chemistry is another important aspect. In the laboratory, there is great interest in industrial processes (e.g., etching, vapor deposition) and-at the fundamental level-in the physics of strong coupling phenomena. Here, the dust (or microparticles) are the dominant component of the multi-species plasma. The particles can be observed in real time and space, individually resolved at all relevant length and time scales. This provides an unprecedented means for studying self-organisation processes in many-particle systems, including the onset of cooperative phenomena. Due to the comparatively large mass of the microparticles (10{sup -12}to10{sup -9}g), precision experiments are performed on the ISS. The following topics will be discussed: Phase transitions, phase separation, electrorheology, flow phenomena including the onset of turbulence at the kinetic level.

Morfill, Gregor E.; Ivlev, Alexei V.; Thomas, Hubertus M. [Max-Planck-Institut fuer Extraterrestrische Physik, D-85740 Garching (Germany)

2012-05-15

102

Atmosphere-Ionosphere Electrodynamic Coupling  

NASA Astrophysics Data System (ADS)

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 formation of plasma density inhomogeneities, the excitation of gamma ray bursts and atmospheric emissions in different spectral bands, the generation of ULF/ELF/VLF electromagnetic waves and plasma turbulence in the ionosphere, the stimulation of radiation belt electron precipitations and the acceleration of ions in the upper ionosphere. The most interesting results of experimental and theoretical studies of these phenomena are discussed below. The ionosphere is subject to the action of the conductive electric current flowing in the atmosphere-ionosphere circuit. We present a physical model of DC electric field and current formation in this circuit. The key element of this model is an external current, which is formed with the occurrence of convective upward transport of charged aerosols and their gravitational sedimentation in the atmosphere. An increase in the level of atmospheric radioactivity results in the appearance of additional ionization and change of electrical conductivity. Variation of conductivity and external current in the lower atmosphere leads to perturbation of the electric current flowing in the global atmosphere-ionosphere circuit and to the associated DC electric field perturbation both on the Earth's surface and in the ionosphere. Description of these processes and some results of the electric field and current calculations are presented below. The seismic-induced electric field perturbations produce noticeable effects in the ionosphere by generating the electromagnetic field and plasma disturbances. We describe the generation mechanisms of such experimentally observed effects as excitation of plasma density inhomogeneities, field-aligned currents, and ULF/ELF emissions and the modification of electron and ion altitude profiles in the upper ionosphere. The electrodynamic model of the ionosphere modification under the influence of some natural and man-made processes in the atmosphere is also discussed. The model is based on the satellite and ground measurements of electromagnetic field and plasma perturbations and on the data on atmospheric radioactivity and soil gas injection into the atmosphere.

Sorokin, V. M.; Chmyrev, V. M.

103

Three studies of impact phenomena in the solar system  

NASA Astrophysics Data System (ADS)

Meteoritic activity affects every body in the solar system; its effects are ubiquitous and therefore very useful in the exploration of many planetary bodies. This work addresses two different current problems associated with the use of impact phenomena in the study of other planetary bodies in our solar system. In Chapter 1 of this thesis, an original method of measuring depths and inferring cross-sectional shapes of impact craters using shadows cast within them by the Sun is developed. The method has the advantage of not requiring that the shadow-front pass through the center of the crater, as the current shadow-measuring technique does. It also has considerable advantages over the methods of stereogrammetry, which requires two images taken from different angles, and photoclinometry, which is sensitive to variations in reflectivity. Three examples providing a check of this method against real lunar impact craters, and demonstrating its utility, are provided. The rest of this work consists of two closely related studies of the effects of Mars's atmosphere, and its variations, on martian impact cratering and meteorite production rates. To date, little account has been taken of these, since the martian atmosphere has been considered too thin to have significant effects. Here, an original approach to the study of large impactor populations, and their effects on planetary surfaces, is developed and applied to Mars. The results show that for small crater sizes (2 m <= D <= 250 m) and impact or masses (10 -1 kg <= m <= 10 7 kg), both processes depend strongly on atmospheric density. Even the current martian atmosphere is dense enough to produce meteorites of over 50 kg, and to substantially reduce small diameter (<30 m) impact cratering. Past, denser atmospheres would have had even greater effects. Therefore, Mars's atmosphere may interfere with surface age estimates based on counts of small craters, and its variations may be reflected in martian impact crater and meteorite populations.

Chappelow, John E.

2005-12-01

104

Mesoscale modeling of the atmosphere  

Microsoft Academic Search

The Naval Research Laboratory (NRL) is presently developing a non-hydrostatic mesoscale model which is suitable for forecasting meso-Beta and gamma scale phenomena over complex terrain. The model will be delivered to the Army in 1997. However, until the non-hydrostatic model becomes operational, HOTMAC (Higher Order Turbulence Model for Atmospheric Circulation) will be used as an operational model in the U.S.

R. P. Pearce

1993-01-01

105

Coupled Ocean-Atmosphere Simulations  

Microsoft Academic Search

\\u000a Climate modelling for the prediction of anthropogenic global change requires to take into account the coupling phenomena between\\u000a the ocean and the atmosphere. Several approaches, ranging from simple dynamical systems studies to full size coupled General\\u000a Circulation Models (GCM) are necessary to apprehend the basic physical processes underlying the climate mean state and its\\u000a seasonal and interannual variability. In this

L. Terray; O. Thual

106

Quantum phenomena in disordered conductors  

NASA Astrophysics Data System (ADS)

In this thesis we consider three separate phenomena that arise in disordered conductors. The first part is devoted to the development of the theory of size and disorder dependence in the Kondo effect. We demonstrate that for a thin film of thickness L with mean-free path ? , disorder provides a correction to the Kondo resistivity of the form t0s/kFL ?2 ln T that explains the disorder-induced depression of the Kondo effect observed experimentally in Cu(Fe) films. In the second part, we study the influence of non-magnetic transition element impurities on conventional superconductivity. We find that phonon coupling at impurities counteracts the traditional effects which dominate Tc suppression in the non-magnetic limit. In some cases, we predict that non-magnetic transition metal impurities can actually enhance Tc . We find qualitative agreement between the predicted increase and the experimental data for IV-VI degenerate semiconductors doped with Tl or In. In the third part, we present a simple qualitative model that interpolates between the high and low temperature properties of quasi-1D conductors. We argue that low-temperature transport is well described by localization theory, with a conductance that decays exponentially with the electron dephasing length. This model is shown to be in quantitative agreement with the experimental data on the organic conductor TTT2I3-d . We also show how the low-temperature positive magnetoresistance observed in TTT2I3-d and other quasi-1D conductors can be explained by the role spin-flip scattering plays in the electron dephasing rate.

Martin, Ivar

107

Exponential analysis in physical phenomena  

NASA Astrophysics Data System (ADS)

Many physical phenomena are described by first-order differential equations whose solution is an exponential decay. Determining the time constants and amplitudes of exponential decays from the experimental data is a common task in semiconductor physics (deep level transient spectroscopy), biophysics (fluorescence decay analysis), nuclear physics and chemistry (radioactive decays, nuclear magnetic resonance), chemistry and electrochemistry (reaction kinetics) and medical imaging. This review article discusses the fundamental mathematical limitations of exponential analysis, outlines the critical aspects of acquisition of exponential transients for subsequent analysis, and gives a comprehensive overview of numerical algorithms used in exponential analysis. In the first part of the article the resolution of exponential analysis as a function of noise in input decays is discussed. It is shown that two exponential decays can be resolved in a transient only if the ratio of their time constants is greater than the resolution limit, which can be explicitly calculated from the signal-to-noise ratio in the transient. Although the signal-to-noise ratio is generally limited by the sensitivity of the equipment, it is shown that digitalization of the decays may be a major source of noise. The requirements for type of analog-to-digital converter, number of digitized data points and duration of digitized transients, which must be met to obtain the theoretical resolution limit and to improve stability of the exponential analysis, are formulated. The second part of the review article gives an overview and comparison of major numerical techniques of exponential analysis, such as the nonlinear least squares fit, the Prony method, the method of modulating functions, the method of moments, the Laplace-Padé approximation, the Tikhonov regularization method, the Gardner transformation, the method of maximum entropy and others.

Istratov, Andrei A.; Vyvenko, Oleg F.

1999-02-01

108

Breakdown phenomena in high power klystrons  

Microsoft Academic Search

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

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

1988-01-01

109

Elimination of undemonstrable phenomena in the EMTP  

Microsoft Academic Search

This paper discusses the undemonstrable phenomena that can occur when the EMTP is used for simulation of some types of networks, consisting of power electronics, and\\/or voltage-, current controlled elements. The synchronous response procedure (SRP) is suggested for elimination of these phenomena. Meanwhile the advantage of the critical damping adjustment technique (CDA) for approximate simulation of the impulse function is

Jiming Lin

1998-01-01

110

Luminous phenomena and earthquakes in southern Washington  

Microsoft Academic Search

Summary Luminous phenomena, mostly nocturnal lights, are associated with very small earthquakes in southern Washington state. The phenomena seem to be electrical in nature, related to earthquake lights, and tend to occur when the locus of earthquake activity moves across an active fault in an area of compressional stress.

J. S. Derr; M. A. Persinger

1986-01-01

111

Neutral Atmospheres  

NASA Astrophysics Data System (ADS)

This paper summarizes the understanding of aeronomy of neutral atmospheres in the solar system, discussing most planets as well as Saturn's moon Titan and comets. The thermal structure and energy balance is compared, highlighting the principal reasons for discrepancies amongst the atmospheres, a combination of atmospheric composition, heliocentric distance and other external energy sources not common to all. The composition of atmospheres is discussed in terms of vertical structure, chemistry and evolution. The final section compares dynamics in the upper atmospheres of most planets and highlights the importance of vertical dynamical coupling as well as magnetospheric forcing in auroral regions, where present. It is shown that a first order understanding of neutral atmospheres has emerged over the past decades, thanks to the combined effects of spacecraft and Earth-based observations as well as advances in theoretical modeling capabilities. Key gaps in our understanding are highlighted which ultimately call for a more comprehensive programme of observation and laboratory measurements.

Mueller-Wodarg, I. C. F.; Strobel, D. F.; Moses, J. I.; Waite, J. H.; Crovisier, J.; Yelle, R. V.; Bougher, S. W.; Roble, R. G.

112

Modeling of Middle Atmosphere Dynamics Using Lower Atmosphere ECMWF Data  

NASA Astrophysics Data System (ADS)

The new circulation model called LIMA (Leibniz-Institute Middle Atmosphere) is used to study the dynamics of the middle atmosphere. LIMA takes advantage of global ECMWF-ERA-40 data sets from troposphere/lower stratosphere regions which are processed through data assimilation techniques. This allows in middle atmosphere modeling to investigate in detail the effects of the lower atmosphere conditions on the upper atmosphere through upward wave activity propagation. One example of LIMA studies is the simulation of the thermal state at the summer upper mesosphere and its impact on the morphology of ice particle related phenomena such as noctilucent clouds (NLC), and polar mesosphere clouds (PMC). LIMA allows to investigate inter-hemispheric differences as well as decadal long term trends in NLC/PMC formation. The NLC/PMC characteristics deduced from LIMA are validated with various data sets from different lidar (ground station ALOMAR), satellite (SBUV, SNOE), rockets and radar observations. LIMA nicely reproduces the mean characteristics of observed ice layers, for example their NH/SH differences in variation with season, altitude, and latitude. Not only seasonal means, but also 11-y solar cycle effects and decadal long term behavior nicely agree with satellite data. This emphasizes the importance of lower atmosphere conditions described by ECMWF data which seem to control to a high degree the thermal state of the upper atmosphere and hence the observed morphology of ice clouds.

Berger, U.; Luebken, F.; Baumgarten, G.

2009-05-01

113

Understanding the Physics of changing mass phenomena  

NASA Astrophysics Data System (ADS)

Changing mass phenomena, like a falling chain or a bungee jumper, might give surprising results, even for experienced physicists. They have resulted in hot discussions in journals, in which for instance Physics professors claim the impossibility of an acceleration larger then g in case of a bungee jumper. These phenomena are also interesting as topics for challenging student projects, and used as such by Dutch high school students. I will take these phenomena as the context in which I like to demonstrate the possibilities of ICT in the learning process of physics. Especially dynamical modeling enables us to describe these phenomena in an elegant way and with knowledge of high school mathematics. Furthermore tools for video-analysis and data from measurements with sensors allow us to study the phenomena in experiments. This example demonstrates the level of implementation of ICT in Physics Education in The Netherlands [1].

Ellermeijer, A. L.

2008-05-01

114

A Review of Low Frequency Electromagnetic Wave Phenomena Related to Tropospheric-Ionospheric Coupling Mechanisms  

NASA Astrophysics Data System (ADS)

Investigation of coupling mechanisms between the troposphere and the ionosphere requires a multidisciplinary approach involving several branches of atmospheric sciences, from meteorology, atmospheric chemistry, and fulminology to aeronomy, plasma physics, and space weather. In this work, we review low frequency electromagnetic wave observations in the Earth-ionosphere cavity from a troposphere-ionosphere coupling perspective. We discuss electromagnetic wave generation, propagation, and resonance phenomena, considering atmospheric, ionospheric and magnetospheric sources, from lightning and transient luminous events at low altitude to Alfvén waves and particle precipitation related to solar and magnetospheric processes. We review ionospheric processes as well as surface and space weather phenomena that drive the coupling between the troposphere and the ionosphere. Effects of aerosols, water vapor distribution, thermodynamic parameters, and cloud charge separation and electrification processes on atmospheric electricity and electromagnetic waves are reviewed. Regarding the role of the lower boundary of the cavity, we review transient surface phenomena, including seismic activity, earthquakes, volcanic processes and dust electrification. The role of surface perturbations and atmospheric gravity waves in ionospheric dynamics is also briefly addressed. We summarize analytical and numerical tools and techniques to model low frequency electromagnetic wave propagation and to solve inverse problems and outline in a final section a few challenging subjects that are important to advance our understanding of tropospheric-ionospheric coupling.

Simões, Fernando; Pfaff, Robert; Berthelier, Jean-Jacques; Klenzing, Jeffrey

2012-06-01

115

Pluto's atmosphere  

NASA Astrophysics Data System (ADS)

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.

Elliot, J. L.; Dunham, E. W.; Bosh, A. S.; Slivan, S. M.; Young, L. A.; Wasserman, L. H.; Millis, R. L.

1989-01-01

116

Interfacial polarization phenomena in organic molecular films.  

PubMed

Electrostatic phenomena occurring at the interface between metal/organic and organic/organic materials are discussed from the viewpoint of dielectrics physics. Focusing on two important origins of surface polarization phenomena, orientational ordering of polar molecules and displacement of excess charges at the interface, surface polarization phenomena of organic thin films are discussed. To define the orientational order of polar molecules, orientational order parameters are introduced, and surface polarization due to the alignment of dipoles is expressed. The generation of Maxwell displacement current (MDC) and optical second harmonic generation (SHG) that are specific for surface organic monomolecular films are discussed, and some experimental evidence are shown. As an extension of the concept of surface Fermi level introduced to discuss the electrostatic phenomena due to electron transfer at the interface between metal-organic insulators, the surface Fermi level is extended to the discussion on the electrostatic phenomena of organic semiconductor materials on metals. In this paper, some experimental evidence of surface polarization originating from polar molecules and displacement of excess charges are shown. After that, with consideration of these surface phenomena, single electron tunneling of organic films are briefly discussed in association with surface polarization phenomena. PMID:17761247

Iwamoto, Mitsumasa; Manaka, Takaaki

2006-01-26

117

Atmospheric chemistry  

SciTech Connect

This book covers the predictive strength of atmospheric models. The book covers all of the major important atmospheric areas, including large scale models for ozone depletion and global warming, regional scale models for urban smog (ozone and visibility impairment) and acid rain, as well as accompanying models of cloud processes and biofeedbacks.

Sloane, C.S. (General Motors Research Labs., Warren, MI (United States)); Tesche, T.W. (Alpine Geophysics (US))

1991-01-01

118

Atmospheric electricity  

Microsoft Academic Search

Owing to the somewhat explosive development of the science of atmospheric electricity during the past decade this article covers a broad field of activity. The article begins with a description and discussion of the work that has been performed to understand the electrical properties of the basic materials involved in generating processes in the atmosphere, namely ice, water, and sand

C D Stow

1969-01-01

119

The Atmosphere.  

ERIC Educational Resources Information Center

|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)|

Ingersoll, Andrew P.

1983-01-01

120

Mathematics needed for Introduction to Transport Phenomena  

NSDL National Science Digital Library

A collection of math problems based on skills needed to successfully complete homework problems in an introductory course in Transport Phenomena. These problems do not introduce any new material for those who have taken Freshman Calculus classes and a sophomore level Differential Equations class. At Purdue University in the required Transport Phenomena course for MSE undergrads (MSE 340), I give a problem set like this the first day of classes in order to make clear the level of mathematical skill needed for the rest of the semester. I have found that it reduces difficulties with math later in the semester, allowing the students to focus on the transport phenomena.

Krane, Matthew J.

2007-10-12

121

Synchronization Phenomena and Epoch Filter of Electroencephalogram  

NASA Astrophysics Data System (ADS)

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.

Matani, Ayumu

122

Transient Phenomena in Asynchronous Motor Drive.  

National Technical Information Service (NTIS)

Transient torques of a motor drive cause torsional stresses in the shaft. Motor is constructed to withstand these torques. In construction of couplings, shaft and drive these torques have to be taken into consideration, too. Transient phenomena are simula...

R. Hirvonen

1989-01-01

123

Exploring the Scope of Controlling Quantum Phenomena.  

National Technical Information Service (NTIS)

During the period of the grant an interrelated set of studies were performed in the general domain of control over quantum dynamics phenomena. A prime focus was on establishing the basic principles of quantum control and their experimental implications. T...

H. Rabitz

2012-01-01

124

Transport Phenomena During Equiaxed Solidification of Alloys.  

National Technical Information Service (NTIS)

Recent progress in modeling of transport phenomena during dendritic alloy solidification is reviewed. Starting from the basic theorems of volume averaging, a general multiphase modeling framework is outlined. This framework allows for the incorporation of...

C. Beckermann H. C. deGroh

1997-01-01

125

Canister storage building natural phenomena design loads  

SciTech Connect

This document presents natural phenomena hazard (NPH) loads for use in the design and construction of the Canister Storage Building (CSB), which will be located in the 200 East Area of the Hanford Site.

Tallman, A.M.

1996-02-01

126

Wave and Fracture Phenomena in Impacted Ceramics.  

National Technical Information Service (NTIS)

An optical measuring technique in combination with high speed photography is provided to solve the problem of this contract, the investigation of wave and fracture phenomena in opaque ceramic materials. Surface disturbances caused by these mechanical even...

S. Winkler

1988-01-01

127

Astronomical Phenomena for the Year 1990.  

National Technical Information Service (NTIS)

This publication contains information extracted from the Astronomical Almanac for the Year 1990. Dates and times of planetary and lunar phenomena and other astronomical data of general interest are presented.

1988-01-01

128

Modeling of fundamental phenomena in welds.  

National Technical Information Service (NTIS)

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 pro...

T. Zacharia J. M. Vitek J. A. Goldak T. A. DebRoy M. Rappaz

1993-01-01

129

Computer Modeling and Animation of Natural Phenomena.  

National Technical Information Service (NTIS)

3D graphics animation is increasingly used in movies and virtual reality computer games to produce realistic visual simulations of physical and natural phenomena. The animation of diffuse liquids such as gases is an indispensable component in such special...

D. S. Ebert J. S. Schpok

2005-01-01

130

Review of Anode Phenomena in Vacuum Arcs.  

National Technical Information Service (NTIS)

This paper reviews anode phenomena in vacuum arcs. It discusses 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 phenomen...

H. C. Miller

1984-01-01

131

Analysis of nuclear reactor instability phenomena  

SciTech Connect

The phenomena known as density-wave instability often occurs in phase change systems, such as boiling water nuclear reactors (BWRS). Our current understanding of density-wave oscillations is in fairly good shape for linear phenomena (eg, the onset of instabilities) but is not very advanced for non-linear phenomena [Lahey and Podowski, 1989]. In particular, limit cycle and chaotic instability modes are not well understood in boiling systems such as current and advanced generation BWRs (eg, SBWR). In particular, the SBWR relies on natural circulation and is thus inherently prone to problems with density-wave instabilities. The purpose of this research is to develop a quantitative understanding of nonlinear nuclear-coupled density-wave instability phenomena in BWRS. This research builds on the work of Achard et al [1985] and Clausse et al [1991] who showed, respectively, that Hopf bifurcations and chaotic oscillations may occur in boiling systems.

Lahey, R.T. Jr.

1993-01-01

132

New phenomena in pulsed FIR gas lasers  

Microsoft Academic Search

New phenomena occur when pulsed far-infrared (FIR) gas lasers are pumped with the pulses of 10 ?m-hybrid-CO2 lasers truncated within 10 ps as well as when truncating directly the FIR laser pulses with the first FIR plasma shutter developed in our laboratory. These new phenomena include, e.g. new interrelations between superradiance, swept-gain superradiance and Raman emission, anticorrelated fluctuations of pump

D. P. Scherrer; J. Knittel; D. B. Moix; M. O. Baumgartner; F. K. Kneubühl

1995-01-01

133

New phenomena in pulsed fir gas lasers  

Microsoft Academic Search

New phenomena occur when pulsed far-infrared (FIR) gas lasers are pumped with the pulses of 10 mum-hybrid-CO2 lasers truncated within 10 ps as well as when truncating directly the FIR laser pulses with the first FIR plasma shutter developed in our laboratory. These new phenomena include, e.g. new interrelations between superradiance, swept-gain superradiance and Raman emission, anticorrelated fluctuations of pump

D. P. Scherrer; J. Knittel; D. B. Moix; M. O. Baumgartner; F. K. Kneubühl

1995-01-01

134

Knowledge based prediction of nonlinear phenomena  

Microsoft Academic Search

A pervasive task in decision making lies in the prediction of unknown phenomena. In the past, the majority of decision support\\u000a tools has addressed linear phenomena or simple nonlinear tasks such as discriminatory analysis. However, recent advances in\\u000a nonlinear theory and software techniques suggest the feasibility of developing generalized tools for analyzing nonlinear signals\\u000a incorporating chaotic features. The goal of

S. H. Kim

2000-01-01

135

Atmospheric Optics  

NSDL National Science Digital Library

Les Cowley, a physicist and expert in atmospheric optics, developed this website to share his knowledge about the visual spectacles produced by light connecting with water drops, dust, and ice crystals. Students can discover how and where the amazing displays are formed. The site is divided into five main categories: Rays and Shadows, Water Droplets, Rainbows, Ice Halos, and High Atmosphere. Within each topic, users can find an abundance of information and amazing images of the particular spectacle. By downloading the HaloSim3 Software in the Ice Halo link, users can view simulations of common and rare halos. Visitors will learn a lot about the atmosphere through this remarkable website.

Cowley, Les

136

Atmospheric holes and small comets  

NASA Astrophysics Data System (ADS)

Global images of Earth's UV dayglow as gained with an imaging photometer on board Dynamics Explorer 1 exhibit transient decreases, or atmospheric holes, in the dayglow intensities over areas with diameters about 50 km. Features of these atmospheric holes include (1) preferential motion in the east-to-west direction across the sunlit face of Earth, (2) similar diurnal variations in occurrence rates as those for radar meteors, (3) correlation of the occurrence rates with the nonshower rates as determined with forward scatter radar, and (4) larger angular diameters for these atmospheric holes when the spacecraft approaches Earth during its perigee passes. These atmospheric holes are interpreted in terms of obscuration of the dayglow by water clouds from the disruption and subsequent vaporization of small comets at low altitudes above the atmosphere. Supporting evidence for the existence of these small comets is given by their telescopic sighting at greater altitudes before disruption and the detection of water bursts in Earth's upper atmosphere. The small-comet hypothesis and its relationship to geophysical, lunar, and interplanetary phenomena are discussed.

Frank, L. A.; Sigwarth, J. B.

1993-02-01

137

Solar Neutrons and Related Phenomena  

NASA Astrophysics Data System (ADS)

EAndersNGrevesse1989Abundances of the elements: meteoritic and solarGeochim Cosmochim Acta (UK)5311972141989GeCoA..53..197A10.1016/0016-7037(89)90286-XAnders E, Grevesse N (1989) Abundances of the elements: meteoritic and solar. Geochim Cosmochim Acta (UK) 53(1):197-214 Aschwanden MJ, Wills MJ, Hudson HS, Kosugi T, Schwartz RA (1996) Electron time-of-flight distances and flare loop geometries compared from CGRO and Yohkoh observations. Astrophys J (USA) 468(1, Part 1):398-417 EAslanidesPFassnachtGDellacasaMGallioJWNTuyn198112C(3He, 3He n)11C cross section at 910 MeVPhys Rev C Nucl Phys (USA)234182618281981PhRvC..23.1826A10.1103/PhysRevC.23.1826Aslanides E, Fassnacht P, Dellacasa G, Gallio M, Tuyn JWN (1981) 12C(3He, 3He n)11C cross section at 910 MeV. Phys Rev C Nucl Phys (USA) 23(4):1826-1828 Avrett EH (1981) Reference model atmosphere calculation - the Sunspot sunspot model. In: Cram LE, Thomas JH (eds) The physics of sunspots, Proceedings of the conference, Sunspot, New Mexico, 1981, conference sponsored by the Sacramento Peak Observatory, Sunspot, NM, pp 235-255, 257 Brekke P, Rottman GJ, Fontenla J, Judge PG (1996) The ultraviolet spectrum of a 3B class flare observed with SOLSTICE. Astrophys J (USA) 468(1, Part 1):418-432 ODBrill1965He3-light nucleus interaction cross sectionsSoviet J Nu

Dorman, Lev I.

138

Atmospheric Potential  

Microsoft Academic Search

UNDER the above heading Mr. Evan McLennan refers in NATURE, February 13, p. 647, to supposed puzzles in atmospheric electricity. That certain difficulties exist no one can deny, but Mr. McLennan's difficulties might, I think, be removed by consultation of existing text-books. The vertical current which he thinks should exist in the atmosphere does exist, and methods of measuring it

C. CHREE C

1913-01-01

139

Atmospheric pollution  

SciTech Connect

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.

Pickett, E.E.

1987-01-01

140

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.

141

Precise Measurement of Atmospheric Gamma Rays at High Altitude  

Microsoft Academic Search

We have been observing the atmospheric gammaray spectrum from 30 GeV to 10 TeV for many years with the emulsion chamber at balloon altitude. Atmospheric gamma rays at high altitude of several g\\/cm2 are almost produced by a single interaction of primary cosmic rays, and useful to interpret the various cosmic-ray phenomena inside the atmosphere. Especially, more conclusive understanding for

T. Kobayashi; Y. Komori; K. Yoshida; J. Nishimura

2001-01-01

142

Atmospheric chemistry: Natural atmospheric acidity  

NASA Astrophysics Data System (ADS)

Formic acid exerts a significant influence on atmospheric chemistry and rainwater acidity. Satellite observations and model simulations suggest that terrestrial vegetation accounts for around 90% of the formic acid produced annually.

Millet, Dylan B.

2012-01-01

143

Investigating the students' understanding of surface phenomena  

NASA Astrophysics Data System (ADS)

This study investigated students' understanding of surface phenomena. The main purpose for conducting this research endeavor was to understand how students think about a complex topic about which they have little direct or formal instruction. The motivation for focusing on surface phenomena stemmed from an interest in integrating research and education. Despite the importance of surfaces and interfaces in research laboratories, in technological applications, and in everyday experiences, no previous systematic effort was done on pedagogy related to surface phenomena. The design of this research project was qualitative, exploratory, based on a Piagetian semi-structured clinical piloted interview, focused on obtaining a longitudinal view of the intended sample. The sampling was purposeful and the sample consisted of forty-four undergraduate students at Kansas State University. The student participants were enrolled in physics classes that spanned a wide academic spectrum. The data were analyzed qualitatively. The main themes that emerged from the analysis were: (a) students used analogies when confronted with novel situations, (b) students mixed descriptions and explanations, (c) students used the same explanation for several phenomena, (d) students manifested difficulties transferring the meaning of vocabulary across discipline boundaries, (e) in addition to the introductory chemistry classes, students used everyday experiences and job-related experiences as sources of knowledge, and (f) students' inquisitiveness and eagerness to investigate and discuss novel phenomena seemed to peak about the time students were enrolled in second year physics classes.

Hamed, Kastro Mohamad

1999-11-01

144

Anomalous Light Phenomena vs. Bioelectric Brain Activity  

NASA Astrophysics Data System (ADS)

We present a research proposal concerning the instrumented investigation of anomalous light phenomena that are apparently correlated with particular mind states, such as prayer, meditation or psi. Previous research by these authors demonstrate that such light phenomena can be monitored and measured quite efficiently in areas of the world where they are reported in a recurrent way. Instruments such as optical equipment for photography and spectroscopy, VLF spectrometers, magnetometers, radar and IR viewers were deployed and used massively in several areas of the world. Results allowed us to develop physical models concerning the structural and time-variable behaviour of light phenomena, and their kinematics. Recent insights and witnesses have suggested to us that a sort of "synchronous connection" seems to exist between plasma-like phenomena and particular mind states of experiencers who seem to trigger a light manifestation which is very similar to the one previously investigated. The main goal of these authors is now aimed at the search for a concrete "entanglement-like effect" between the experiencer's mind and the light phenomena, in such a way that both aspects are intended to be monitored and measured simultaneously using appropriate instrumentation. The goal of this research project is twofold: a) to verify quantitatively the existence of one very particular kind of mind-matter interaction and to study in real time its physical and biophysical manifestations; b) to repeat the same kind of experiment using the same test-subject in different locations and under various conditions of geomagnetic activity.

Teodorani, M.; Nobili, G.

145

Development of sodar detection and its application for studies of atmospheric boundary layer in Beijing, China  

Microsoft Academic Search

In China the dovelopment of acoustic detection and the studies on the structure of atmospheric boundary layer over land and ocean and the assessment of atmospheric environment with the sodar data have been carried out for more than twenty years. The main achievements of these investigations have been comprehenced in this paper. Some phenomena in the atmospheric boundary layer, such

Mingyu Zhou

146

An effort to simulate magnetospheric-ionospheric effects in the presence of seismic phenomena  

NASA Astrophysics Data System (ADS)

The paper describes the Soviet MACS (Magnetospheric-Atmospheric Coupling through Seismoacoustic phenomena) program, in which the effects of simulated earthquakes on processes in the magnetosphere and ionosphere were investigated. Seismic events were simulated by the explosion of large charges containing several hundreds of tons of TNT. Particular consideration is given to data acquired from the blast (288 tons of TNT) in the vicinity of Alma-Ata on November 28, 1981. A scheme describing the effect of the seismic waves on the upper atmosphere is elaborated.

Alperovich, L. S.; Vugmeister, B. O.; Gokhberg, M. B.; Drobzhev, V. I.; Erushchenkov, A. I.; Ivanov, E. A.; Kudriavtsev, V. P.; Kulichkov, S. N.; Krasnov, V. M.; Matveev, A. K.

147

Spin-transfer phenomena in layered magnetic structures: Physical phenomena and materials aspects  

Microsoft Academic Search

During the past 20 years, layered structures consisting of ferromagnetic layers and spacers of various material classes with a thickness of only a few nanometers have revealed a variety of exciting and potentially very useful phenomena not present in bulk material. Representing distinct manifestations of spin-transfer processes, these phenomena may be categorized into interlayer exchange coupling (IEC), giant magnetoresistance (GMR),

P. Grünberg; D. E. Bürgler; H. Dassow; A. D. Rata; C. M. Schneider

2007-01-01

148

Atmospheric radiation  

SciTech Connect

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.

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

1991-01-01

149

Synthetic study of precursory phenomena of the M7.2 Hyogo-ken Nanbu earthquake  

NASA Astrophysics Data System (ADS)

Many seismic precursory phenomena in the ionosphere, atmosphere, and underground water were observed by professional and amateur people before the M7.2 Hyogo-ken Nanbu earthquake of January 17, 1995. The seismic precursory phenomena are a tornado-type seismic cloud ascending over Nojima fault near the epicenter, anomalous foEs increases above 7 MHz observed at epicentral distances within about 500 km, anomalous ELF VLF radio noises from lightning discharges, anomalous extensions of the characteristic terminator times toward darker local times in phase variations of Omega 10.2 kHz waves passing about 70 km north of the epicenter, radon concentration increases in the atmosphere on a fault in Kobe and those in the underground water near a subsurface fault in Nishinomiya, and radon ion density increases in Okayama about 200 km west of the epicenter. We study synthetically relations among these seismic precursory phenomena in the ionosphere, atmosphere, and underground water before this earthquake onset. Then, we propose desirable observations for warning great earthquakes.

Ondoh, T.; Hayakawa, M.

150

Solid-State Physical Phenomena and Effects Part III  

Microsoft Academic Search

This is the third in a series of four articles describing solid-state phenomena. Twelve solid-state phenomena and physical effects are provided. All of the twelve phenomena belong to a group which includes effects related to the dielectric properties of materials and transport phenomena for particles other than electrons or holes.

E. Scheibner

1962-01-01

151

Numerical Simulation of Pulse Detonation Engine Phenomena  

Microsoft Academic Search

This paper describes one- and two-dimensional numerical simulations, with simplified as well as full reaction kinetics, of a single cycle pulse detonation engine (PDE). The present studies explore the igni- tion energies associated with the initiation of a det- onation in the PDE tube, and quantify reactive flow phenomena, performance parameters, and noise gen- eration associated with full and simplified

Xing He; Ann R. Karagozian

2003-01-01

152

Simple Phenomena, Slow Motion, Surprising Physics  

ERIC Educational Resources Information Center

|This article describes a few simple experiments that are worthwhile for slow motion recording and analysis either because of interesting phenomena that can be seen only when slowed down significantly or because of the ability to do precise time measurements. The experiments described in this article are quite commonly done in Czech schools. All…

Koupil, Jan; Vicha, Vladimir

2011-01-01

153

Gods, Heroes and Natural Phenomena Cosmologies  

Microsoft Academic Search

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

Miguel Angel Alarcón

154

Corporate strategy and the Social Networking phenomena  

Microsoft Academic Search

The Social Networking (SN) phenomena has developed relatively overnight and is continuing to develop at an exponential pace. It allows for innovative new methods of disseminating and collecting information in ways never before dreamed possible by corporate executives. The rise of Social Networking is becoming a disruptive technology for traditional marketing and advertising medium such as radio, television, web page,

Robert L. Johnson

2010-01-01

155

Flow Cytometric Measurements of Cell Surface Phenomena.  

National Technical Information Service (NTIS)

The study of cell surface phenomena by flow cytometry has been pursued by several groups. These studies have produced new insights into a variety of areas of biology. However, the capabilities of flow systems have not been fully exploited. A technique for...

J. H. Jett

1979-01-01

156

Corruption, fraud and cybercrime as dehumanizing phenomena  

Microsoft Academic Search

Purpose – The purpose of this paper is to describe corruption, fraud and cybercrime as dehumanizing phenomena. Design\\/methodology\\/approach – Berdiaeff's notion of slavery and Sartre's concepts of lie and bad faith are used in order to put light on the dehumanizing effects of corruption, fraud and cybercrime over social life itself. Findings – Corruption, fraud and cybercrime constitute dehumanizing processes

Michel Dion

2011-01-01

157

Solidification phenomena in metal matrix nanocomposites  

Microsoft Academic Search

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

Michael Peter de Cicco

2009-01-01

158

Basic ablation phenomena during laser thrombolysis  

Microsoft Academic Search

This paper presents studies of microsecond ablation phenomena that take place during laser thrombolysis. The main goals were to optimize laser parameters for efficient ablation, and to investigate the ablation mechanism. Gelatin containing an absorbing dye was used as the clot model. A parametric study was performed to identify the optimal wavelength, spot size, pulse energies, and repetition rate for

Ujwal S. Sathyam; Alan Shearin; Scott A. Prahl

1997-01-01

159

Breakdown phenomena in high-power klystrons  

Microsoft Academic Search

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. In addition, a renewed interest in breakdown phenomena for ns pulse, MV\\/cm fields has been sparked by recent R and D work in the area of GW rf sources. The most important

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

1989-01-01

160

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...

161

Ambroise August Liébeault and Psychic Phenomena  

Microsoft Academic Search

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

Carlos S. Alvarado

2009-01-01

162

Finite element modeling of electromagnetic NDT phenomena  

Microsoft Academic Search

The development of computer-based defect characterization schemes for automated electromagnetic methods of nondestructive testing (NDT) requires adequate mathematical models to describe the complicated interactions of currents, fields and defects in materials. This paper describes the finite element equations governing active, residual and eddy current phenomena in materials with discontinuities and magnetic nonlinearity. It is suggested that the resulting magnetic vector

R. Palanisamy; W. Lord

1979-01-01

163

Electrode phenomena in slagging MHD channels  

Microsoft Academic Search

A theoretical and experimental study of electrode phenomena as they relate to the interfacial current transport in slagging MHD channels is presented. An analytical study of the stability of the current transport in the vicinity of electrode walls is given. The critical current density for arcing is shown to depend on the temperature of the plasma or slag-wall interface as

S. Petty; A. Demirjian; A. Solbes

1977-01-01

164

Paramagnetic Meissner effect and related dynamical phenomena  

Microsoft Academic Search

The hallmark of superconductivity is the diamagnetic response to external magnetic field. In striking contrast to this behavior, a paramagnetic response or paramagnetic Meissner effect was observed in ceramic high-Tc and in conventional superconductors. The present review is given on this interesting effect and related phenomena. We begin with a detailed discussion of experimental results on the paramagnetic Meissner effect

Mai Suan Li

2003-01-01

165

Zoom lens without focus-breathing phenomena  

Microsoft Academic Search

Assuming that exit pupil position is fixed, it is presented a zoom lens having a focusing mechanism which does not give rise to any changes in the angular field of view. A frontal part set in front of the zooming part consists of two movable components for focusing. The paraxial condition in which no focus breathing phenomena exist is, in

Kazuo Tanaka

2001-01-01

166

Transient phenomena in compressor stations during surge  

Microsoft Academic Search

Transient phenomena are generally inherent in the operation of compressor stations: These are either fast or slow transients. A model describing the governing equation for the gas dynamics, control system, compressor and turbine shaft inertias has been developed. The effect of these inertias is manifested by an example of a compressor station operating near the surge control line. Another example

K. K. Botros

1994-01-01

167

Quantum macroscopic coherent phenomena in biocommunication  

Microsoft Academic Search

The proposal of coherent electromagnetic processes as the engine for biological dynamics and biocommunications suggest that the quantum macroscopic coherent phenomena as Bose condensation and laser threshold could be present in living cells. A possible correlation between environmental primordial cosmic background radiation and Josephson experimental evidence is discussed.

M. Branescu

2002-01-01

168

Passive Localization Methods based on Distributed Phenomena  

Microsoft Academic Search

This paper is devoted to methods for localizing individual sensor nodes connected in a network. The novelty of the proposed method is the model-based approach (i.e., rigorous exploitation of physical background knowledge) using local observations of a distributed phenomenon. By unobtrusively exploiting background phenomena, the individual sensor nodes can be localized by only locally measuring its surrounding without the necessity

Felix Sawo; Thomas C. Henderson; Christopher Sikorski; Uwe D. Hanebeck

169

Simple Phenomena, Slow Motion, Surprising Physics  

ERIC Educational Resources Information Center

This article describes a few simple experiments that are worthwhile for slow motion recording and analysis either because of interesting phenomena that can be seen only when slowed down significantly or because of the ability to do precise time measurements. The experiments described in this article are quite commonly done in Czech schools. All…

Koupil, Jan; Vicha, Vladimir

2011-01-01

170

Interfacial phenomena in lithium polymer electrolyte batteries  

Microsoft Academic Search

Thin-layer, rechargeable lithium batteries are considered among the most promising advanced systems for electric vehicle or consumer electronics applications. The study of the characteristics of the electrode interface, with particular concern for the negative lithium\\/polymer electrolyte side, is considered. Since clarification of the interfacial phenomena is crucial in assessing the effective practical impact of the polymer batteries, the authors have

F. Croce; F. Gerace; B. Scrosati

1992-01-01

171

Whither the Future of Controlling Quantum Phenomena?  

Microsoft Academic Search

This review puts into perspective the present state and prospects for controlling quantum phenomena in atoms and molecules. The topics considered include the nature of physical and chemical control objectives, the development of possible quantum control rules of thumb, the theoretical design of controls and their laboratory realization, quantum learning and feedback control in the laboratory, bulk media influences, and

Herschel Rabitz; Regina de Vivie-Riedle; Marcus Motzkus; Karl Kompa

2000-01-01

172

Apparatus Based Experimental Study of Physics Phenomena  

Microsoft Academic Search

Basic measurement concepts of a new apparatus for the experimental study of physics phenomena based on laser modules and detectors are presented in this paper. Construction details of the proposed apparatus are also described. Measurement time base is 100 musec (depending on the microprocessor used) and in each cycle, data coming from eight photo-detectors are stored. When an experiment is

Theodore Pachidis; Kostas Tarchanidis; John. Lygouras

2006-01-01

173

Change blindness phenomena for stereoscopic projection systems  

Microsoft Academic Search

In visual perception, change blindness describes the phenomenon that persons viewing a visual scene may apparently fail to detect significant changes in that scene. These phenomena have been observed in both computer generated imagery and real-world scenes. Several studies have demonstrated that change blindness effects occur primarily during visual disruptions such as blinks or saccadic eye movements. However, until now

Frank Steinicke; Gerd Bruder; Klaus Hinrichs; Pete Willemsen

2010-01-01

174

Study of the Interaction between Biological Cells of Different Shapes and Sizes and Electromagnetic Fields Produced by Natural Phenomena  

Microsoft Academic Search

We carry out a study of the interaction between electromagnetic fields produced innature and cells with no structure but with different shapes and sizes, considered asapproximations of those observed in the human body. Magnetic fields produced byvarious atmospheric and geomagnetic phenomena are compared with the fieldsgenerated by the cells themselves. Working with frequencies up to 105 Hz, we found that

Rosa Diaz-Sandoval; Blanca Mendoza

2004-01-01

175

Effects on the Ionosphere Due to Phenomena Occurring Below it  

NASA Astrophysics Data System (ADS)

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.

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

2003-03-01

176

Work on Planetary Atmospheres and Planetary Atmosphere Probes  

NASA Astrophysics Data System (ADS)

A summary final report of work accomplished is presented. Work was performed in the following areas: (1) Galileo Probe science analysis, (2) Galileo probe Atmosphere Structure Instrument, (3) Mars Pathfinder Atmosphere Structure/Meteorology instrument, (4) Mars Pathfinder data analysis, (5) Science Definition for future Mars missions, (6) Viking Lander data analysis, (7) winds in Mars atmosphere Venus atmospheric dynamics, (8) Pioneer Venus Probe data analysis, (9) Pioneer Venus anomaly analysis, (10) Discovery Venus Probe Titan probe instrument design, and (11) laboratory studies of Titan probe impact phenomena. The work has resulted in more than 10 articles published in archive journals, 2 encyclopedia articles, and many working papers. This final report is organized around the four planets on which there was activity, Jupiter, Mars, Venus, and Titan, with a closing section on Miscellaneous Activities. A major objective was to complete the fabrication, test, and evaluation of the atmosphere structure experiment on the Galileo probe, and to receive, analyze and interpret data received from the spacecraft. The instrument was launched on April 14, 1989. Calibration data were taken for all experiment sensors. The data were analyzed, fitted with algorithms, and summarized in a calibration report for use in analyzing and interpreting data returned from Jupiter's atmosphere. The sensors included were the primary science pressure, temperature and acceleration sensors, and the supporting engineering temperature sensors. Computer programs were written to decode the Experiment Data Record and convert the digital numbers to physical quantities, i.e., temperatures, pressures, and accelerations. The project office agreed to obtain telemetry of checkout data from the probe. Work to extend programs written for use on the Pioneer Venus project included: (1) massive heat shield ablation leading to important mass loss during entry; and (2) rapid planet rotation, which introduced terms of motion not needed on Venus. When the Galileo Probe encountered Jupiter, analysis and interpretation of data commenced. The early contributions of the experiment were to define (1) the basic structure of the deep atmosphere, (2) the stability of the atmosphere, (3) the upper atmospheric profiles of density, pressure, and temperature. The next major task in the Galileo Probe project was to refine, verify and extend the analysis of the data. It was the verified, and corrected data, which indicated a dry abiabatic atmosphere within measurement accuracy. Temperature in the thermosphere was measured at 900 K. Participation in the Mars atmospheric research included: (1) work as a team member of the Mars Atmosphere Working Group, (2) contribution to the Mars Exobiology Instrument workshop, (3) asssistance in planning the Mars global network and (4) assitance in planning the Soviet-French Mars mission in 1994. This included a return to the Viking Lander parachute data to refine and improve the definition of winds between 1.5 and 4 kilometer altitude at the two entry sites. The variability of the structure of Mars atmosphere was addressed, which is known to vary with season, latitude, hemisphere and dust loading of the atmosphere. This led to work on the Pathfinder project. The probe had a deployable meteorology mast that had three temperature sensors, and a wind sensor at the tip of the mast. Work on the Titan atmospheric probe was also accomplished. This included developing an experiment proposal to the European Space Agency (ESA), which was not selected. However, as an advisor in the design and preparation of the selected experiment the researcher interacted with scientist on the Huygens Probe Atmosphere Structure Experiment. The researcher also participated in the planning for the Venus Chemical Probe. The science objectives of the probe were to resolve unanswered questions concerning the minor species chemistry of Venus' atmosphere that control cloud formation, greenhouse effectiveness, and the thermal structure. The researcher also reviewed problems with the

Lester, Peter

1999-01-01

177

Crystal Melting and Wall Crossing Phenomena  

NASA Astrophysics Data System (ADS)

This paper summarizes recent developments in the theory of Bogomol'nyi-Prasad-Sommerfield (BPS) state counting and the wall crossing phenomena, emphasizing in particular the role of the statistical mechanical model of crystal melting. This paper is divided into two parts, which are closely related to each other. In the first part, we discuss the statistical mechanical model of crystal melting counting BPS states. Each of the BPS state contributing to the BPS index is in one-to-one correspondence with a configuration of a molten crystal, and the statistical partition function of the melting crystal gives the BPS partition function. We also show that smooth geometry of the Calabi-Yau manifold emerges in the thermodynamic limit of the crystal. This suggests a remarkable interpretation that an atom in the crystal is a discretization of the classical geometry, giving an important clue as to the geometry at the Planck scale.In the second part we discuss the wall crossing phenomena. Wall crossing phenomena states that the BPS index depends on the value of the moduli of the Calabi-Yau manifold, and jumps along real codimension one subspaces in the moduli space. We show that by using type IIA/M-theory duality, we can provide a simple and an intuitive derivation of the wall crossing phenomena, furthermore clarifying the connection with the topological string theory. This derivation is consistent with another derivation from the wall crossing formula, motivated by multi-centered BPS extremal black holes. We also explain the representation of the wall crossing phenomena in terms of crystal melting, and the generalization of the counting problem and the wall crossing to the open BPS invariants.

Yamazaki, Masahito

2010-02-01

178

Mesoscale modeling of the atmosphere  

NASA Astrophysics Data System (ADS)

The Naval Research Laboratory (NRL) is presently developing a non-hydrostatic mesoscale model which is suitable for forecasting meso-Beta and gamma scale phenomena over complex terrain. The model will be delivered to the Army in 1997. However, until the non-hydrostatic model becomes operational, HOTMAC (Higher Order Turbulence Model for Atmospheric Circulation) will be used as an operational model in the U.S. Army's IMETS (Integrated METeorological System) to make a short-range (up to 24 hours) forecast of battlescale atmospheric phenomena. The U.S. Army is mainly concerned with meteorological conditions spatially within the area of 500 km x 500 km x 10 km or less and temporally within the period of 24 hours or less. The Army Research Laboratory's (ARL) prototype IMETS is currently receiving the forecast and analysis fields of meteorological variables produced from the U.S. Air Force Global Spectral Model (GSM) through the Automated Weather Distribution System (AWDS). In the near future, the Relocatable Window Model (RWM) output is expected to become available. The RWM is the Air Force's regional meso-alpha model similar to the Navy Operational Regional Atmospheric Prediction System (NORAPS). The U.S. Army is planning to use the output of GSM (or RWM) to initialize and assimilate into HOTMAC. HOTMAC has been used extensively at the ARL (formerly Atmospheric Sciences Laboratory), and simulate the evolution of locally forced circulations due to surface heating and cooling over meso-Beta and gamma scale areas. HOTMAC is numerically stable and easy to use and thus, suitable for operational use.

Pearce, R. P.

1993-03-01

179

Atmospheric Modeling  

Microsoft Academic Search

\\u000a Air quality models simulate the atmospheric concentrations and deposition fluxes to the Earth’s surface of air pollutants\\u000a by solving the mass conservation equations that represent the emissions, transport, dispersion, transformations and removal\\u000a of those air pollutants and associated chemical species. Contemporary air quality models can be grouped into two major categories:\\u000a (1) models that calculate the concentrations of air pollutants

Christian Seigneur; Robin Dennis

180

Atmospheric Acoustics  

NASA Astrophysics Data System (ADS)

This chapter deals with sound propagation in the atmosphere, which is an important link in the functional chain from noise emissions from aircraft, road and rail vehicles, and wind turbines to noise perception. The principle processes in outdoor sound propagation are explained. They include refraction, diffraction, and reflection. Two sound propagation models for scientific applications are briefly outlined. Finally, three illustrative applications and their results are discussed.

Heimann, Dietrich; Schady, Arthur; Feng, Joseph

181

The Atmosphere  

NSDL National Science Digital Library

The lessons at this website were prepared to introduce 5th-8th grade students to the fundamental principles of the earth's atmosphere: history, composition, and structure. Includes three pages of information and features to allow for exploration and expansion of current knowledge. In addition, there are four activities to develop performance skills, not only in science, but in math and language arts as well. Links to external sites also included.

182

Auroral Phenomena: Associated with auroras in complex ways are an extraordinary number of other physical phenomena.  

PubMed

The array of auroral phenomena involves all the basic types of physical phenomena: heat, light, sound, electricity and magnetism, atomic physics, and plasma physics. The uncontrollability, the unreproducibility, and the sheer enormity of the phenomena will keep experimentalists and theorists busy but unsatisfied for many years to come. The greatest challenge in this field of research is an adequate experimentally verifiable theory of the local energization of auroral particle fluxes. Once that is achieved, there is every likelihood that the multitude of correlations between auroral phenomena can be understood and appreciated. Until that time, however, such correlations are to be regarded like icebergs-the parts that can be seen are only a small fraction of the whole phenomenon, and it is the large unseen parts that can be dangerous to theorists and experimentalists alike. PMID:17842831

O'brien, B J

1965-04-23

183

Research on atmospheric volcanic emissions - An overview  

NASA Astrophysics Data System (ADS)

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.

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.

1982-09-01

184

How Might You Investigate Scientific Phenomena?  

NSDL National Science Digital Library

This site, part of Exploring Earth Investigation by McDougal Littell and TERC, examines how to investigate scientific phenomena. The investigations "were designed to build students' knowledge of Earth Science conceptsâ¦and to raise student awareness of Earth as a system of interconnected components and processes." Here, visitors will learn about the steps that allow scientists to create valid investigations of phenomena: forming a hypothesis, determining the appropriate method of investigation, collecting and graphing data, and hypothesis testing. Many sections have illustrative images and interactive features which help students understand the topics presented, and the final section ends with questions for students to further explore as well as a link to some NASA datasets. This is an excellent site for any Earth Science classroom as an introductory lecture to the scientific method or as an out-of-class exploration for students.

2008-09-05

185

Phase-interface phenomena in multiphase flow  

SciTech Connect

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.

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

186

Computer Simulation of Relaxation Phenomena in Plasmas  

NASA Astrophysics Data System (ADS)

Man-machine Interactive System for Simulation (MISSION) has been developed to explore Simulation Science, in which an advanced virtual reality visualization system is the important element. Plasma is an exemplar of a medium governed by complexity, and plasma physics research is evolving from a "static science" into a "dynamic science". In this paper, a topic in Simulation Science on nonlinear behavior of plasma physics is picked up, specifically, energy relaxation phenomena. Three-dimensional simulations are executed to clarify physical mechanisms of relaxation activities that are observed in the spherical tokamak and helical plasma experiments. Transition phenomena are observed in the simulation results, where a plasma spontaneously deforms itself into a configuration that it prefers. For the spherical tokamak, a new nonlinear trigger mechanism of relaxation is found, in which the n=1 (n is the toroidal mode number) activity in the core region is subsequently excited by development of higher n ballooning modes in the periphery region.

Hayashi, Takaya

2002-08-01

187

Phenomena of carbon atom redistribution in martensite  

Microsoft Academic Search

Phenomena related to the redistribution of carbon atoms prior to carbide precipitation (tempering) are considered in this\\u000a paper. 1) Order-disorder processes are described, and the influence of several factors is considered. It is shown that the\\u000a lattice conjugation and coherence between different variants of martensite plates as well as between martensite plates and\\u000a austenite leads to a disappearance of the

G. V. Kurdjumov; A. G. Khachaturyan

1972-01-01

188

AC electrokinetic phenomena generated by microelectrode structures.  

PubMed

The field of AC electrokinetics is rapidly growing due to its ability to perform dynamic fluid and particle manipulation on the micro- and nano-scale, which is essential for Lab-on-a-Chip applications. AC electrokinetic phenomena use electric fields to generate forces that act on fluids or suspended particles (including those made of dielectric or biological material) and cause them to move in astonishing ways. Within a single channel, AC electrokinetics can accomplish many essential on-chip operations such as active micro-mixing, particle separation, particle positioning and micro-pattering. A single device may accomplish several of those operations by simply adjusting operating parameters such as frequency or amplitude of the applied voltage. Suitable electric fields can be readily created by micro-electrodes integrated into microchannels. It is clear from the tremendous growth in this field that AC electrokinetics will likely have a profound effect on healthcare diagnostics, environmental monitoring and homeland security. In general, there are three AC Electrokinetic phenomena (AC electroosmosis, dielectrophoresis and AC electrothermal effect) each with unique dependencies on the operating parameters. A change in these operating parameters can cause one phenomena to become dominant over another, thus changing the particle or fluid behavior. It is difficult to predict the behavior of particles and fluids due to the complicated physics that underlie AC electrokinetics. It is the goal of this publication to explain the physics and elucidate particle and fluid behavior. Our analysis also covers how to fabricate the electrode structures that generate them, and how to interpret a wide number of experimental observations using several popular device designs. This video article will help scientists and engineers understand these phenomena and may encourage them to start using AC Electrokinetics in their research. PMID:19066515

Hart, Robert; Oh, Jonghyun; Capurro, Jorge; Noh, Hongseok Moses

2008-07-28

189

Novel phenomena in macroscopic photonic crystals  

NASA Astrophysics Data System (ADS)

Photonic crystals provide superb opportunities for tailoring of the photonic density of states. This ability can in turn be explored to control radiation into far-field, enhance fluorescent light emission, as well as optimize laser emission. In order to make these phenomena useful for large macroscopic devices, large-area nano-fabrication techniques have to be successfully implemented. In this talk, I will present some of our recent theoretical and experimental progress in exploring these opportunities.

Zhen, Bo; Chua, Song-Liang; Lee, Jeongwon; Qiu, Wenjun; Rodriguez, Alejandro W.; Liang, Xiangdong; Johnson, Steven G.; Joannopoulos, John D.; Shapira, Ofer; Soljacic, Marin

2013-09-01

190

Modelling of flow phenomena during DC casting  

Microsoft Academic Search

Modelling of Flow Phenomena during DC Casting Jan Zuidema\\u000aThe production of aluminium ingots, by semi-continuous casting, is a complex process. DC Casting stands for direct chill casting. During this process liquid aluminium transforms to solid aluminium while cooling down. This is not an instantaneous transformation, but occurs in temperature interval. In the casting process the latent heat is moved

J. Zuidema

2005-01-01

191

New critical phenomena observed under weightlessness  

Microsoft Academic Search

A review is given of several new phenomena observed when the effects of gravity are suppressed in fluids and liquid mixtures\\u000a near a critical point. A new mechanism of heat transport, the “Piston effect”, has been discovered. This mechanism is due\\u000a to the expansion of a conductive thermal boundary layer and leads to a “critical speeding up” instead of the

D. Beysens

1996-01-01

192

A new mechanism for lunar transient phenomena  

SciTech Connect

Lunar transient phenomena, which are changes in lunar surface brightness observed over the course of four centuries, are presently characterized by a novel mechanism in which electrodynamic effects associated with rock fracturing could account for the sporadic optical pulses noted near specific lunar features. It is suggested that only mild seismic activity, or perhaps thermal cracking, may be required for the activation of the proposed mechanism. 22 refs.

Zito, R.R. (Lockheed Missiles and Space Co., Inc., Sunnyvale, CA (USA))

1989-12-01

193

COMPACTNESS AND INCOMPACTNESS PHENOMENA IN SET THEORY  

Microsoft Academic Search

Abstract. We prove two results with a common,theme: the tension between compactness and incompactness phenomena,in combinatorial set theory. The- orem 1 uses PCF theory to prove a sort of “compactness” for a version of Dzamonja and Shelah’s strong non-reflection principle. Theorem 2 investi- gates Jensen’s subcompact cardinals and their relationship with stationary set reflection and the failure of the square

James Cummings

194

A linear transport equation for wave phenomena  

Microsoft Academic Search

We formulate a linear, time dependent transport equation for vector wave phenomena by considering a three—dimensional space filled up homogeneously with isotropic bundles of linear ideal flexible strings which are linearly coupled at each point. We determine the restrictions imposed on the form of such a transport equation by the requirements of isotropy, space inversion, time—invariance, causality, time—reversal, conservation of

Marijan Ribaric; Luka Sustersic

1987-01-01

195

Conceptions of water-related phenomena  

Microsoft Academic Search

Water is an important resource. Surprisingly, research into students' conceptions of water has been confined largely to studies\\u000a of change of state. This paper reports the results of interviews about underground water, water pollution, the water cycle,\\u000a and change of state). There were 45 students interviewed about these phenomena: all were in Year 9 or Year 10 in Western Australia

R. A. Schibeci; A. Fetherstonhaugh; S. Griffin

1993-01-01

196

Coronal Mass Ejections (CMEs) and Associated Phenomena  

NASA Astrophysics Data System (ADS)

The Sun is the most powerful radio waves emitting object in the sky. The first documented recognition of the reception of radio waves from the Sun was made in 1942 by Hey.15 Since then solar radio observations, from ground-based and space-based instruments, have played a major role in understanding the physics of the Sun and fundamental physical processes of the solar radio emitting phenomena...

Manoharan, P. K.

2008-10-01

197

The demystification of autoscopic phenomena: Experimental propositions  

Microsoft Academic Search

Autoscopic phenomena (AP) are rare, illusory visual experiences during which the subject has the impression of seeing a second\\u000a own body in extrapersonal space. AP consist of out-of-body experience, autoscopic hallucination, and heautoscopy. Recent neurologic\\u000a reports support the role of multisensory integration deficits of bodyrelated information and vestibular dysfunctions in AP\\u000a at the temporo-parietal junction. A caveat to test the

Christine Mohr; Olaf Blanke

2005-01-01

198

Natural phenomena hazards site characterization criteria  

SciTech Connect

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.

Not Available

1994-03-01

199

Magnetic reconnection in the solar lower atmosphere  

NASA Astrophysics Data System (ADS)

The solar chromosphere and the transition region is a short layer in the solar lower atmosphere, which, however, is full of dynamic phenomena, such as Ellerman bombs, blinkers, transion region explosive events, microflares, and so on. These phenomena are presented at different wavelengths, and have quite different behaviors. It has been gradually realized that they may all be related to magnetic reconnection. It has been shown that, significantly different from the reconnection in the corona, the magnetic reconnection in the solar lower atmosphere is strongly affected by the ionization, radiation, abrupt stratification, and even the p-mode waves. In this paper, we review the observations and modelings of the subtle effects of these processes on the magnetic reconnection.

Chen, Peng Fei; Fang, Cheng

200

First application of the radioholographic method to wave observations in the upper atmosphere  

Microsoft Academic Search

Wave phenomena in the upper atmosphere can be studied using the high-precision Global Positioning System (GPS) radio navigational field. In this paper, basic principles, accuracy, and vertical resolution of the radioholographic technique for studies of ionospheric wave phenomena are presented for the general case when the orbits of the satellites are arbitrary. Results of testing of the radioholographic method are

A. Pavelyev; K. Igarashi; C. Reigber; K. Hocke; J. Wickert; G. Beyerle; S. Matyugov; A. Kucherjavenkov; D. Pavelyev; O. Yakovlev

2002-01-01

201

Physics and chemistry of upper atmospheres of planets from infrared observations  

Microsoft Academic Search

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

Theodor Kostiuk

1994-01-01

202

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

NASA Astrophysics Data System (ADS)

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 lightning activity as it lies in Indian Ocean and also the height of the magnetic field lines connecting the conjugate regions lies in the ionosphere/atmosphere, lot of interesting VLF activity through the magnetosphere is observed in Indian low latitude region. Sub-ionospheric VLF transmissions propagating inside the Earth-ionosphere wave-guide is also being widely used for investigating sudden ionospheric perturbations in lower part of the ionosphere. For this purpose we propose to monitor VLF signals continuously at several locations in Indian sector with the help of AWESOME VLF receivers from Stanford University. AWESOME receivers are capable of collecting both broadband (used for the study of natural signals) and narrowband (sub-ionospheric VLF signals corresponding to VLF transmitters) data. The obtained data will enable us to understand the generation and propagation mechanism of radio atmospherics from lightning flashes, magnetospheric whistlers, VLF emissions and other naturally occurring phenomena. Narrowband sub- ionospheric VLF signals and ground based geomagnetic data in Indian low latitude region will help us to study sudden ionospheric disturbances associated with transient phenomena like solar flares, geomagnetic storms, cosmic gamma-ray flares, etc.

Singh, R.; Veenadhari, B.; Alex, S.

2006-11-01

203

Studies of Novel Quantum Phenomena in Ruthenates  

SciTech Connect

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).

Mao, Zhiqiang

2011-04-08

204

Spontaneous Anomalystic Phenomena, Pragmatic Information and Formal Representations of Uncertainty  

Microsoft Academic Search

I discuss the application of the Model of Pragmatic Information to the study of spontaneous anomalystic mental phenomena like\\u000a telepathy, precognition, etc. In these phenomena the most important effects are related to anomalous information gain by the\\u000a subjects. I consider the basic ideas of the Model, as they have been applied to experimental anomalystic phenomena and to\\u000a spontaneous phenomena that

Stefano Siccardi

2011-01-01

205

A neuroanatomical model of passivity phenomena.  

PubMed

Any attempt to elucidate the nature and mechanism of passivity phenomena, i.e., experiences that one's conscious actions or thoughts have not been 'willed' by oneself, requires an integrative philosophical-neurobiological approach. The model proposed here adopts some fundamental positions that have long been advocated by philosophers and theoretical psychologists and have now found support from functional neuroanatomy. First, we experience our actions not from the standpoint of the executive but through the perception of its effects. Second, the 'self' is not an agent of behaviour. Third, behaviour is energized and integrated by basic drives (instincts). Fourth, the view that the experience of an acting self is related to drive reduction associated with voluntary actions is perhaps less well developed. The model thus proposes that passivity phenomena are actions that are induced by the perception of salient events but that are not integrated with or conducive to the overall motivational state of the organism. It has been suggested that, following the perception of salient events, competition arises between automatic response tendencies seeking expression. The prefrontal cortex appears to play an important role not only in determining which events are to be perceived but also which of the corresponding response dispositions is to be selected and actualized in overt behaviour. Thus, action selection is the outcome of competition between response tendencies in the context of prefrontal biasing signals that represent drives and strivings for goals. Action selection may be uncoupled from drives and strivings as a result of a lowering of the threshold for action selection--as is suggested to be the case in schizophrenic passivity phenomena--or due to disconnection from prefrontal regions--as may be the case in the alien limb syndrome. PMID:15336249

Behrendt, Ralf-Peter

2004-09-01

206

Preferential dissolution phenomena of nuclear waste materials  

SciTech Connect

Preferential dissolution of polyphase nuclear waste materials in short term leach tests can exaggerate radionuclide release rates when extrapolated to the lifetime of the waste form. Possible preferential leach phenomena are associated with the presence of cracks, intergranular phases and readily soluble phases. The rate of dissolution and the microstructural connectivity of the most soluble phase determine the period over which perferential dissolution is observable. The connectivity of phases is amenable to control during processing by altering the starting green density of the precursor powders.

Clarke, D.R.; Flintoff, J.F.

1983-01-01

207

High-temperature phenomena in flares  

SciTech Connect

High temperature phenomena occurring in solar flares are reviewed based on hard X-ray images and spectral analyses of highly ionized iron lines observed aboard the Hinotori spacecraft. Five basic flare components are proposed, i.e., impulsive (I); gradual hard (GH); thermal (T); quasi thermal (QT); and hot thermal (HT) components. Every flare showed some combination of the five components. It is pointed out that data for energy release and transport for each component would give a lot of variety to the hard X-ray image, spectrum and time history of X-rays. 26 references.

Takakura, T.; Tanaka, K.

1984-01-01

208

General unifying features of controlled quantum phenomena  

SciTech Connect

Many proposals have been put forth for controlling quantum phenomena, including open-loop, adaptive feedback, and real-time feedback control. Each of these approaches has been viewed as operationally, and even physically, distinct from the others. This work shows that all such scenarios inherently share the same fundamental control features residing in the topology of the landscape relating the target physical observable to the applied controls. This unified foundation may provide a basis for development of hybrid control schemes that would combine the advantages of the existing approaches to achieve the best overall performance.

Pechen, Alexander; Brif, Constantin; Wu, Rebing; Chakrabarti, Raj; Rabitz, Herschel [Department of Chemistry, Princeton University, Princeton, New Jersey 08544 (United States)

2010-09-15

209

Solid-State Physical Phenomena and Effects Part IV  

Microsoft Academic Search

This is the fourth in a series of articles dealing with phenomena of the solid state. Nineteen solid-state phenomena and physical effects are described. This group of phenomena includes primarily the resonance effects, that is, those effects which can be described in terms of discrete energy levels rather than energy bands.

E. Scheibner

1962-01-01

210

EZ lidar dust transit phenomena observations in Seoul, Korea  

NASA Astrophysics Data System (ADS)

Duststorms and sandstorms regularly devastate Northeast Asia and cause considerable damage to transportation system and public health; further, these events are conceived to be one of the very important indices for estimating the global warming and desertification. Previously, yellow sand events were considered natural phenomena that originate in deserts and arid areas. However, the greater scale and frequency of these events in recent years are considered to be the result of human activities such as overgrazing and over-cultivation. Japan, Korea, Cina and Mongolia are directly concerned to prevent and control these storms and have been able to some extent to provide forecasts and early warnings. In this framework, to improve the accuracy of forecasting , a compact and rugged eye safe lidar, the EZ LIDATM, developed together by Laboratoire des Sciences du Climat et l'Environnement (LSCE) (CEA-CNRS) and LEOSPHERE (France) to study and investigate structural and optical properties of clouds and aerosols, thanks to the strong know-how of CEA and CNRS in the field of air quality measurements and cloud observation and analysis, was deployed in Seoul, Korea in order to detect and study yellow sand events, thanks to its depolarization channel and scan capabilities. The preliminary results, showed in this paper, of this measurement campaign put in evidence that EZ Lidar, for its capabilities of operating unattended day and night under each atmospheric condition, is mature to be deployed in a global network to study long-range transport, crucial in the forecasting model.

Lolli, S.; Sauvage, L.; Loaec, S.

2009-09-01

211

Dissipation-Induced Instability Phenomena in Infinite-Dimensional Systems  

NASA Astrophysics Data System (ADS)

This paper develops a rigorous notion of dissipation-induced instability in infinite dimensions as an extension of the classical concept implicitly introduced by Thomson and Tait for finite degree of freedom mechanical systems over a century ago. Here we restrict ourselves to a particular form of infinite-dimensional systems—partial differential equations—whose inherent function-analytic differences from finite-dimensional systems make uncovering this notion more intricate. In building the concept of dissipation-induced instability in infinite dimensions we found Arnold’s and Yudovich’s nonlinear stability methods, for conservative and dissipative systems respectively, along with some new existence theory for solutions, to be the essential foundation. However, when proving the results for classical solutions, as motivated by their direct physical significance, we had to overcome a number of fundamental difficulties associated with existing stability analysis methods, which has led to new techniques. In particular, in this work we establish the connection of existence and general stability theories in strong and weak topologies and provide new insights into the physics and geometry of the dissipation-induced instability phenomena in infinite-dimensional systems. As a paradigm and the first infinite-dimensional example to be rigorously analyzed, we use a two-layer quasi-geostrophic beta-plane model, which describes the fundamental baroclinic instability in atmospheric and ocean dynamics; early formal linear approximate studies suggested that this system can be destabilized after the introduction of dissipation.

Krechetnikov, Rouslan; Marsden, Jerrold E.

2009-11-01

212

An Overview of Earth's Global Electric Circuit and Atmospheric Conductivity  

Microsoft Academic Search

The Earth's global atmospheric electric circuit depends on the upper and lower atmospheric boundaries formed by the ionosphere and the planetary surface. Thunderstorms and electrified rain clouds drive a DC current (˜1 kA) around the circuit, with the current carried by molecular cluster ions; lightning phenomena drive the AC global circuit. The Earth's near-surface conductivity ranges from 10-7 S m-1

Michael J. Rycroft; R. Giles Harrison; Keri A. Nicoll; Evgeny A. Mareev

2008-01-01

213

The Center for Natural Phenomena Engineering (CNPE), 1990--1991. [Earthquake and other natural phenomena engineering  

SciTech Connect

The Center for Natural Phenomena Engineering (CNPE) was established to provide a natural phenomena (NP) engineering oversight role within Martin Marietta Energy Systems, Inc. (MMES). In this oversight role CNPE's goals are to provide coordination and direction of activities related to earthquake and other natural phenomena engineering, including development of hazard definition, development of design criteria, conducting new facility design, development and conducting of testing, performance of analysis and vulnerability studies, development of analysis methodology, and provision of support for preparation of safety analysis reports for the five MMES sites. In conducting these activities it is CNPE's goal to implement the elements of Total Quality Management (TQM) in a cost-effective manner, providing its customers with a quality product. This report describes 1990--1991 activities.

Not Available

1992-07-01

214

Animal network phenomena: insights from triadic games  

NASA Astrophysics Data System (ADS)

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.

Mesterton-Gibbons, Mike; Sherratt, Tom N.

215

Quantum Phenomena Tested By Neutron Interferometry  

NASA Astrophysics Data System (ADS)

Entanglement of two photons, or atoms is a complementary situation to a double slit situation of a single photon, neutron or atom. With neutrons single particle interference phenomena can be observed and the ``entanglement of degrees of freedom'', i.e. contextuality can be verified. In this respect, neutrons are proper tools for testing quantum mechanics because they are massive, they couple to electromagnetic fields due to their magnetic moment and they are subject to all basic interactions, and they are sensitive to topological effects, as well. Related experiments will be discussed. Deterministic and stochastic partial absorption experiments can be described by Bell-type inequalities. Recent neutron interferometry experiments based on postselection methods renewed the discussion about quantum nonlocality and the quantum measuring process. It has been shown that interference phenomena can be revived even when the overall interference pattern has lost its contrast. This indicates a persisting coupling in phase space even in cases of spatially separated Schrödinger cat-like situations. These states are extremely fragile and sensitive against any kind of fluctuations and other decoherence processes. More complete quantum experiments also show that a complete retrieval of quantum states behind an interaction volume becomes impossible in principle.

Rauch, Helmut

2005-02-01

216

WHC natural phenomena hazards mitigation implementation plan  

SciTech Connect

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.

Conrads, T.J.

1996-09-11

217

Effects of electrostatic correlations on electrokinetic phenomena  

NASA Astrophysics Data System (ADS)

The classical theory of electrokinetic phenomena is based on the mean-field approximation that the electric field acting on an individual ion is self-consistently determined by the local mean charge density. This paper considers situations, such as concentrated electrolytes, multivalent electrolytes, or solvent-free ionic liquids, where the mean-field approximation breaks down. A fourth-order modified Poisson equation is developed that captures the essential features in a simple continuum framework. The model is derived as a gradient approximation for nonlocal electrostatics of interacting effective charges, where the permittivity becomes a differential operator, scaled by a correlation length. The theory is able to capture subtle aspects of molecular simulations and allows for simple calculations of electrokinetic flows in correlated ionic fluids. Charge-density oscillations tend to reduce electro-osmotic flow and streaming current, and overscreening of surface charge can lead to flow reversal. These effects also help to explain the suppression of induced-charge electrokinetic phenomena at high salt concentrations.

Storey, Brian D.; Bazant, Martin Z.

2012-11-01

218

Short pulse phenomena produced with long pulses  

NASA Astrophysics Data System (ADS)

We have found a way to produce to phenomena usually associated with ultrashort laser pulses using surprisingly long pulses. For example, the spatial asymmetry of a dissociating molecule has been observed to vary with the CEP for very short intense pulses [1-3]. By using chirped pulses with large bandwidths, however, our calculations show large, CEP-dependent asymmetry in dissociating H2^+ even for 100 fs long pulses. This effect is also shown in the spatial asymmetry of an ionized atomic target. We also find varying the bandwidth and the direction of the chirp of the pulse can affect another multi-photon process, zero-photon dissociation of H2^+ [4]. While it is not obvious how these unexpected phenomena can be explained in the usual time-dependent, field-based picture, their explanation in terms of a photon picture is rather straightforward, underscoring its utility even in the strong field regime. [1] M. F. Kling et al., Science 312, 246 (2006). [2] M. Kremer et al., Phys. Rev. Lett. 103, 213003 (2009). [3] V. Roudnev, B. D. Esry, and I. Ben-Itzhak, Phys. Rev. Lett. 93, 163601 (2004). [4] J. H. Posthumus et al. J. Phys. B: At. Mol. Opt. Phys. 28, 623 (2004).

Hernández, J. V.; Esry, B. D.

2011-06-01

219

Multiscale phenomena in the Earth's Magnetosphere  

NASA Astrophysics Data System (ADS)

The multiscale phenomena in the Earth's magnetosphere have been studied using data from ground-based and space-borne measurements. The ground-based observations provide data over decades and are suitable for characterizing the inherent nature of the multiscale behavior and for studying the dynamical and statistical features. On the other hand, the spacecraft data provide in-situ observations of the processes. The multipoint measurements by Cluster have provided a new understanding of the plasma processes at microand meso-scales and the cross-scale coupling among them. The role of cross-scale coupling is evident in phenomena such as bursty bulk flows, flux ropes, and reconnection. The characteristic scales of the processes range from electron skin depth to MHD scales and the modeling of these processes need different physical models, such as kinetic, EMHD, Hall MHD, and MHD. The ground-based data have been used to develop models based on techniques of nonlinear science and yield predictive models which can be used for forecasting. These models characterize the magnetospheric dynaics and yield its global and multiscale aspects. The distribution of scales in the magnetosphere is studied using an extensive database of the solar wind and the magnetosphere. The distributions of the waiting times deviate significantly from a power law as well as stretched exponential distributions, and show a scaling with respect to the mean, indicating a limited role of long-term correlations in the magnetospheric dynamics.

Surjalal Sharma, A.

220

Sonoluminescence and other energy focusing phenomena  

NASA Astrophysics Data System (ADS)

Fluids and solids that are driven off equilibrium do not return smoothly to the equilibrium state. Instead they can display a wide range of energy focusing phenomena. In sonoluminescence a sound wave passing through a fluid has its energy concentrated by 12 orders of magnitude to create ultraviolet picosecond flashes of light. For 30KHz sound waves the spectrum is a blackbody yet its size is so small as to confound theory. At the very low frequencies achieved with a water hammer the strength of a single flash can be up-scaled by 6 orders of magnitude so as to be visible to this audience, in a real time demonstration. In a ferroelectric crystal such as Lithium Tantalate the application of heat leads to the expulsion of electrons with energies that can exceed 100KeV. Upon striking a target x-rays are emitted. A crucial question relates to whether there exist experimental configurations in which these processes can be used to generate nuclear fusion. Energy focusing also plays a role in turbulence, where intermittency leads to the formation of unexpected structures. Static electricity generated by friction is another striking example of an energy focusing effect. In the 'barometer light' dragging glass through mercury at a speed of 1mm/sec leads to picosecond electrical discharges where the electrons are accelerated to over 1% the speed of light. Experiments indicate that this effect is related to phenomena encompassed by everyday friction.

Putterman, Seth

2005-03-01

221

Quantum Phenomena Tested By Neutron Interferometry  

SciTech Connect

Entanglement of two photons, or atoms is a complementary situation to a double slit situation of a single photon, neutron or atom. With neutrons single particle interference phenomena can be observed and the 'entanglement of degrees of freedom', i.e. contextuality can be verified. In this respect, neutrons are proper tools for testing quantum mechanics because they are massive, they couple to electromagnetic fields due to their magnetic moment and they are subject to all basic interactions, and they are sensitive to topological effects, as well. Related experiments will be discussed. Deterministic and stochastic partial absorption experiments can be described by Bell-type inequalities. Recent neutron interferometry experiments based on postselection methods renewed the discussion about quantum nonlocality and the quantum measuring process. It has been shown that interference phenomena can be revived even when the overall interference pattern has lost its contrast. This indicates a persisting coupling in phase space even in cases of spatially separated Schroedinger cat-like situations. These states are extremely fragile and sensitive against any kind of fluctuations and other decoherence processes. More complete quantum experiments also show that a complete retrieval of quantum states behind an interaction volume becomes impossible in principle.

Rauch, Helmut [Atominstitut der Oesterreichischen Universitaeten, 1020 Vienna (Austria)

2005-02-15

222

Mathematical methods of studying physical phenomena  

NASA Astrophysics Data System (ADS)

In recent decades, substantial theoretical and experimental progress was achieved in understanding the quantum nature of physical phenomena that serves as the foundation of present and future quantum technologies. Quantum correlations like the entanglement of the states of composite systems, the phenomenon of quantum discord, which captures other aspects of quantum correlations, quantum contextuality and, connected with these phenomena, uncertainty relations for conjugate variables and entropies, like Shannon and Rényi entropies, and the inequalities for spin states, like Bell inequalities, reflect the recently understood quantum properties of micro and macro systems. The mathematical methods needed to describe all quantum phenomena mentioned above were also the subject of intense studies in the end of the last, and beginning of the new, century. In this section of CAMOP 'Mathematical Methods of Studying Physical Phenomena' new results and new trends in the rapidly developing domain of quantum (and classical) physics are presented. Among the particular topics under discussion there are some reviews on the problems of dynamical invariants and their relations with symmetries of the physical systems. In fact, this is a very old problem of both classical and quantum systems, e.g. the systems of parametric oscillators with time-dependent parameters, like Ermakov systems, which have specific constants of motion depending linearly or quadratically on the oscillator positions and momenta. Such dynamical invariants play an important role in studying the dynamical Casimir effect, the essence of the effect being the creation of photons from the vacuum in a cavity with moving boundaries due to the presence of purely quantum fluctuations of the electromagnetic field in the vacuum. It is remarkable that this effect was recently observed experimentally. The other new direction in developing the mathematical approach in physics is quantum tomography that provides a new vision of quantum states. In the tomographic picture of quantum mechanics, the states are identified with fair conditional probability distributions, which contain the same information on the states as the wave function or the density matrix. The mathematical methods of the tomographic approach are based on studying the star-product (associative product) quantization scheme. The tomographic star-product technique provides an additional understanding of the associative product, which is connected with the existence of specific pairs of operators called quantizers and dequantizers. These operators code information on the kernels of all the star-product schemes, including the traditional phase-space Weyl-Wigner-Moyal picture describing the quantum-system evolution. The new equation to find quantizers, if the kernel of the star product of functions is given, is presented in this CAMOP section. For studying classical systems, the mathematical methods developed in quantum mechanics can also be used. The case of paraxial-radiation beams propagating in waveguides is a known example of describing a purely classical phenomenon by means of quantum-like equations. Thus, some quantum phenomenon like the entanglement can be mimicked by the properties of classical beams, for example, Gaussian modes. The mathematical structures and relations to the symplectic symmetry group are analogous for both classical and quantum phenomena. Such analogies of the mathematical classical and quantum methods used in research on quantum-like communication channels provide new tools for constructing a theoretical basis of the new information-transmission technologies. The conventional quantum mechanics and its relation to classical mechanics contain mathematical recipes of the correspondence principle and quantization rules. Attempts to find rules for deriving the quantum-mechanical formalism starting from the classical field theory, taking into account the influence of classical fluctuations of the field, is considered in these papers. The methods to solve quantum equations and formulate the boundary co

Man'ko, Margarita A.

2013-03-01

223

Some Recent Advances in Hydrologic and Atmospheric Sensor Technology  

Microsoft Academic Search

The long standing challenge that faces all hydrologists and atmospheric scientists is the spatial and temporal complexity of the land surface and the desire to have high resolution measurements of surface fluxes and various state variables. Three recent advances in sensor technology are discussed and their application in the field for improved understanding of hydrologic phenomena is presented: 1. A

M. Parlange; V. Simeonov; G. Barrenetxea; H. Huwald; O. Couach; V. Luyet; E. Bou-Zeid; M. Vetterli; J. Selker; I. Serikov; P. Ristori; M. Froidevaux; H. van den Bergh

2007-01-01

224

INFLUENCE OF THE TURBULENCE OF ATMOSPHERE DURIG OPTIC MEASUREMENTS  

Microsoft Academic Search

Turbulent phenomena in the atmosphere, which lead to fluctuation of the intensity of the optical signal, are the cause for additional errors in optical and electronic goniometric devices. A quantitative evaluation of these errors is presented in this paper. Different goniometric devices are used in optical and electronic devices for targeting, chasing and control. These goniometric devices consist mainly of

Stiliyan Stoyanov; Valya Dimitrova; Angel Manev; Kunyu Palazov

2007-01-01

225

University Corporation for Atmospheric Research: Digital Image Library  

NSDL National Science Digital Library

This site provides access to weather and climate imagery, including unique visuals of atmospheric and solar phenomena, pollution, clouds, research instruments, field projects, landscapes, and educational settings. It also contains links to other digital image sites and a place to store personally selected images for later viewing.

226

In Brief: Atmospheric brown cloud report  

NASA Astrophysics Data System (ADS)

The combined effects of human-made atmospheric brown clouds (ABCs) and greenhouse gases in the atmosphere are having broad-based impacts, including causing some cities to get darker, contributing to faster melting of some glaciers, masking the effects of climate change, and having negative effects on agriculture and air quality, according to a 13 November report released by the United Nations Environment Programme (UNEP). ``We believe today's report brings ever more clarity to the ABC phenomena and in doing so must trigger an international response, one that tackles the twin threats of greenhouse gases and brown clouds and the unsustainable development that underpins both,'' said Veerabhadran Ramanathan, head of the UNEP scientific panel carrying out the research and a professor at the Scripps Institution of Oceanography, La Jolla, Calif. The report, ``Atmospheric brown clouds: Regional assessment report with focus on Asia,'' can be found at http://www.unep.org.

Showstack, Randy

2008-11-01

227

Microbiology and atmospheric processes: research challenges concerning the impact of airborne micro-organisms on the atmosphere and climate  

NASA Astrophysics Data System (ADS)

For the past 200 years, the field of aerobiology has explored the abundance, diversity, survival and transport of micro-organisms in the atmosphere. Micro-organisms have been explored as passive and severely stressed riders of atmospheric transport systems. Recently, an interest in the active roles of these micro-organisms has emerged along with proposals that the atmosphere is a global biome for microbial metabolic activity and perhaps even multiplication. As part of a series of papers on the sources, distribution and roles in atmospheric processes of biological particles in the atmosphere, here we describe the pertinence of questions relating to the potential roles that air-borne micro-organisms might play in meteorological phenomena. For the upcoming era of research on the role of air-borne micro-organisms in meteorological phenomena, one important challenge is to go beyond descriptions of abundance of micro-organisms in the atmosphere toward an understanding of their dynamics in terms of both biological and physico-chemical properties and of the relevant transport processes at different scales. Another challenge is to develop this understanding under contexts pertinent to their potential role in processes related to atmospheric chemistry, the formation of clouds, precipitation and radiative forcing. This will require truly interdisciplinary approaches involving collaborators from the biological and physical sciences, from disciplines as disparate as agronomy, microbial genetics and atmosphere physics, for example.

Morris, C. E.; Sands, D. C.; Bardin, M.; Jaenicke, R.; Vogel, B.; Leyronas, C.; Ariya, P. A.; Psenner, R.

2011-01-01

228

Self-Organised Criticality and the Atmospheric Sciences: selected review, new findings and future directions  

Microsoft Academic Search

Self-organised criticality (SOC) has been considered by some the foremost candidate for a universal theory of complexity. A review of past studies of SOC in the context of the atmospheric sciences, an area of relative neglect, is conducted. Using empirical data from extreme weather and climate events (hurricanes, windstor ms and tornadoes) it is shown that these atmospheric phenomena display

Suraje Dessai; Martin E. Walter

229

Measurement of atmospheric water vapour on the ground's surface by radio waves  

Microsoft Academic Search

Water vapour in the atmosphere and various meteorological phenomena are essential to the understanding of the mechanism of the water cycle. However, it is very difficult to observe water vapour in the atmosphere because the quantities are usually observed at a single point not over long intervals or in a specific plane or volume. Accordingly, the use of radio waves

Tokuo Kishii; Yasuhisa Kuzuha; Fumi Sugita; Michiko Hayano

2001-01-01

230

A new hypothesis on meandering atmospheric flows in low wind speed conditions  

Microsoft Academic Search

Low wind speeds are often associated with high pollutant concentrations in the atmosphere. Dispersion modelling in such conditions is still an important challenge for scientists due to phenomena associated with low wind speeds, which are not well understood. One such phenomenon is the large horizontal oscillation of the atmosphere, which is called meandering. This study aims at providing a new

D. Oettl; A. Goulart; G. Degrazia; D. Anfossi

2005-01-01

231

Large Interface Simulation in Multiphase Flow Phenomena  

SciTech Connect

An attempt to represent multiphase multi-scale flow, filling the gap between Direct Numerical Simulation (DNS) and averaged approaches, is the purpose of this paper. We present a kind of Large Interface (LI) simulation formalism obtained after a filtering process on local instantaneous conservation equations of the two-fluid model which distinguishes between small scales and large scales contributions. LI surface tension force is also taken into account. Small scale dynamics call for modelization and large scale for simulation. Joined to this formalism, a criterion to recognize LI's is developed. It is used in an interface recognition algorithm which is qualified on a sloshing case and a bubble oscillation under zero-gravity. This method is applied to a rising bubble in a pool that collapses at a free surface and to a square-base basin experiment where splashing and sloshing at the free surface are the main break-up phenomena. (authors)

Henriques, Aparicio; Coste, Pierre; Pigny, Sylvain [CEA-Grenoble, 17, rue des Martyrs 38054 Grenoble Cedex 9 (France); Magnaudet, Jacques [Institut Mecanique des Fluides de Toulouse, 1 Allee du Professeur Camille Soula, 31400 Toulouse (France)

2006-07-01

232

Nonlinear phenomena induced by infrared laser light  

NASA Astrophysics Data System (ADS)

Results are reported from observations of different nonlinear phenomena occurring in the IR laser-solid interaction during positive feedback between the 'thermal' and 'chemical' degrees of freedom of the system via the changes in the absorption characteristics of the target. It is shown experimentally that by varying the control parameters, different spatio-temporal structures such as periodic, stochastic, and autooscillations of the thermal field on the irradiated surface due to CW and pulsed IR lasers could be registered. Possible hydrodynamic flows for 1D and 2D irradiation are represented. The synchronous motion of hot points on a surface irradiated by means of two independent YAG lasers into two parallel focal spots with different distances is shown.

Nanai, L.

233

Using Spatial Gradients to Model Localization Phenomena  

SciTech Connect

We present the final report on a Laboratory-Directed Research and Development project, Using Spatial Gradients to Model Localization Phenomena, performed during the fiscal years 1996 through 1998. The project focused on including spatial gradients in the temporal evolution equations of the state variables that describe hardening in metal plasticity models. The motivation was to investigate the numerical aspects associated with post-bifurcation mesh dependent finite element solutions in problems involving damage or crack propagation as well as problems in which strain Localizations occur. The addition of the spatial gradients introduces a mathematical length scale that eliminates the mesh dependency of the solution. In addition, new experimental techniques were developed to identify the physical mechanism associated with the numerical length scale.

D.J.Bammann; D.Mosher; D.A.Hughes; N.R.Moody; P.R.Dawson

1999-07-01

234

Electric and electromagnetic phenomena in meteor trails  

NASA Astrophysics Data System (ADS)

The present study examines experimental and theoretical investigations of electric and electromagnetic phenomena in meteor trails conducted in the past, and makes a general overview of the problem. It is concluded that the problem has yet to be developed on a serious theoretical level. All the research done in the 1960s is based on different approaches and, as a rule, does not contain mutual criticism and discussion. It can be considered proven that a meteor body acquires during ablation a positive stabilized charge with a potential of several volts. A quasi-hydrodynamic approach to kinetic equations for electron and ion motion in a meteor trail can be used to analyze the first stage of the formation of a meteor trail and to verify the charge separation concept.

Bronshten, V. A.

1991-04-01

235

Critical phenomena in N=2* plasma  

SciTech Connect

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.

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

236

Hadronic and nuclear phenomena in quantum chromodynamics  

SciTech Connect

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.

Brodsky, S.J.

1987-06-01

237

Efficient Numerical Modeling of Nonequilibrium Fluctuation Phenomena  

NASA Astrophysics Data System (ADS)

We present efficient numerical methods for computing non-equilibrium Casimir forces and radiative heat transfer between bodies of complex shapes and realistic material properties. Our methods borrow techniques from computational electromagnetism (specifically, surface integral equations and boundary-element methods) to describe fluctuations in fields in terms of fluctuating sources on the surfaces of material bodies. We obtain concise formulas expressing forces and heat-transfer rates in terms of traces of matrix products, where the elements of the matrices describe the interactions of tangential currents flowing on the surfaces of the interacting material bodies. Using our methods, we obtain new predictions of nonequilibrium phenomena in geometries that would be difficult or impossible to treat using other methods for modeling nonequilibrium fluctuations.

Homer Reid, M. T.; Rodriguez, Alejandro; Johnson, Steven

2013-03-01

238

Critical and resonance phenomena in neural networks  

NASA Astrophysics Data System (ADS)

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.

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

2013-01-01

239

From fundamental fields to nuclear phenomena  

SciTech Connect

Research in nuclear physics is becoming increasingly interdisciplinary. At the interface of nuclear and particle physics, there are efforts to understand the nucleon and the NN interaction based on the underlying quark substructure as described by a fundamental field theory (QCD). There are also substantial efforts to apply field theories to broader areas of nuclear physics, including nucleon-nucleon scattering, nuclear structure, relativistic transport theory, and ultrarelativistic heavy ion collisions. Many of the techniques applied to these processes have been borrowed from atomic physics, where applications of a fundamental field theory (QED) have become standard technology. This workshop concentrated on a variety of open problems in the application of field theory to nuclear phenomena and brought together a diverse group of theoreticians working in nuclear, particle and atomic physics. Separate abstracts were prepared for 23 papers of this conference.

McNeil, J.A. (ed.) (Colorado School of Mines, Golden, CO (United States)); Price, C.E. (ed.) (Univ. of Colorado, Boulder, CO (United States))

1991-01-01

240

Computer simulation of nonlinear phenomena in plasmas  

NASA Astrophysics Data System (ADS)

Simulation Science is explored by developing Man-machine Interactive System for Simulation (MISSION), in which an advanced virtual reality visualization system is an important element. Plasma is an exemplar of a medium governed by complexity, and plasma physics research is evolving from a ``static science'' into a ``dynamic science''. In this paper, a topic in Simulation Science on nonlinear behavior of plasma physics is picked up, specifically, energy relaxation phenomena. Three-dimensional simulations are executed to clarify physical mechanisms of relaxation activities that are observed in the spherical tokamak experiments. The simulation results predict an occurrence of self-organizing transition from an axisymmetric state to a stable /n=2 helical state.

Complexity Simulation Group; Hayashi, Takaya

2001-12-01

241

Earth's Ionosphere as a Gigantic Detector of Extra-terrestrial Energetic Phenomena: A Review  

NASA Astrophysics Data System (ADS)

The paper presents the ionospheric effects due to radiation from the transient extraterrestrial sources like Gamma Ray Bursts, Soft Gamma Ray Repeaters, Anomalous X-ray Pulsars, X-ray novae and X-ray transient sources. Gamma rays could penetrate deep in the atmosphere due to their high energy in comparison with other types of radiation. If the transient radiation from the above sources is strong enough to enhance the ionospheric ionization, VLF radio propagation could be affected. In the paper, we discuss the evidences of detection of such phenomena in VLF data and explain some of the observations using theoretical considerations.

Mondal, S. K.; Chakrabarti, S. K.

2010-10-01

242

Bow Shock and Upstream Phenomena at Mars  

NASA Astrophysics Data System (ADS)

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.

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

243

Photonic coherence phenomena in coupled optical resonators  

NASA Astrophysics Data System (ADS)

A structure consisting of N coupled optical resonators exhibits resonances that split into N higher-Q modes due to coherent coupling between resonators. This has a direct analogy with other types of oscillators. In particular, for two (or any even number of) coupled optical resonators, this mode splitting leads to a cancellation of absorption on resonance as a result of classical destructive interference of the symmetric and antisymmetric modes of the system. An analogy between this effect and electromagnetically-induced transparency in an atomic system is explored. Furthermore, a variety of photonic coherence phenomena in passive and active coupled optical resonators is investigated. Specifically, the effective dispersive and absorptive steady-state response of coupled resonators is derived and used to determine the conditions for coupled-resonator-induced transparency and absorption, lasing without gain, and cooperative cavity emission. These effects rely on coherent photon trapping, in direct analogy with coherent population trapping phenomena in atomic systems. It is also demonstrated that the coupled-mode equations are formally identical to the two-level atom Schrodinger equation in the rotating-wave approximation. The impulse response of coupled resonators is also derived. It is found that the coupled-resonator photon dynamics display damped Rabi oscillations, which facilitates adiabatic coherent photon transfer techniques such as stimulated Raman adiabatic passage. These effects are predicted directly from coupled-mode theory, and thus are not unique to atoms, but rather are fundamental to systems of coherently coupled resonators. It is also theoretically predicted that in coupled optical resonators slow and fast light can propagate without attenuation. In systems of coupled resonators, slow light can propagate without attenuation by a cancellation of absorption as a result of mode splitting and destructive interference, whereas transparent fast light propagation can be achieved with the assistance of gain and splitting of the intracavity resonances, which consequently switches the dispersion from normal to anomalous.

Chang, Hongrok

244

Physics of atmospheric luminous anomalies: a sieve for SETI?  

NASA Astrophysics Data System (ADS)

Anomalous atmospheric light phenomena reoccur in many locations of Earth, some of which have become a laboratory area for a rigorous instrumented study of the involved physics. Three Italian missions to Hessdalen (Norway) furnished crucial multi-wavelength data, the analysis of which has recently permitted us to establish that the very most part of light phenomena are caused by a geophysical mechanism producing light balls whose structure and radiant characteristics are very similar to the ones of ball lightning. While most of light phenomena in Hessdalen and elsewhere can now be successfully explained within the framework of a natural mechanism, a residual of "locally overlapping data" remains presently unexplained. To investigate them also the ETV (Extraterrestrial Visitation) working hypothesis is taken into account. It is shown how the search for ETV (SETV), consistent with the assumption of interstellar and galactic diffusion, can be carried out only from a rigorous data screening coming originally from the study of natural phenomena.

Teodorani, M.

2004-06-01

245

VERITAS: An Atmospheric Imaging Calorimeter  

SciTech Connect

VERITAS is one of a new generation of imaging air Cerenkov telescope arrays built to study astrophysical sources emitting gamma rays in the GeV to TeV energy range. The catalog of objects that can be studied by these ground-based instruments is expanding rapidly. The observations now possible make a critical contribution to understanding some of the most energetic phenomena in the universe. The imaging Cerenkov technique makes use of atmospheric calorimetry. The types of objects studied and the optical nature of ground-based gamma-ray telescopes places them solidly within the field of astronomy. However, the strong connections to particle processes, the electronic instrumentation, and reconstruction methods are those familiar to high energy particle physics. The advances in instrumentation that have brought about the current success of the field are reviewed and prospects for future improvements discussed.

Hays, Elizabeth [Enrico Fermi Institute, 5640 S. Ellis Ave, University of Chicago, Chicago, Illinois 60637 (United States); Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2006-10-27

246

Martian atmospheric entry profiles and atmospheric tides  

NASA Astrophysics Data System (ADS)

In this study we revisit trajectory and atmospheric reconstructions during Mars Entry Decent and Landing (EDL) with a specific focus on the Phoenix mission. Oscillations in temperature profiles derived from atmospheric entry probes are caused by a wide variety of waves and tides. We analyze vertical wavelengths and amplitudes of these oscillations in order to identify the effects of atmospheric tides on atmospheric entry profiles. The atmospheric profiles and the tidal analysis are compared with previous Mars entry reconstruction studies as well as with orbital remote sensing data such as those by the Mars Climate Sounder (MCS) instrument on the Mars Reconnaissance Orbiter (MRO).

Karatekin, Özgür; Van Hove, Bart; Verbruggen, Wim

2013-04-01

247

In Situ Visualization of Impacting Phenomena of Plasma-Sprayed Zirconia: From Single Splat to Coating Formation  

Microsoft Academic Search

The authors have developed an in situ monitoring system for particle impacts under atmospheric dc plasma spraying conditions.\\u000a This system utilized a high-speed video camera coupled with a long-distance microscope, and was capable of capturing the particle-impinging\\u000a phenomena at one million frames per second. To understand the coating formation mechanism, two approaches were attempted,\\u000a i.e., observation of the single splat formation

Kentaro Shinoda; Hideyuki Murakami; Seiji Kuroda; Kohsei Takehara; Sachio Oki

2008-01-01

248

Different states of the transient luminous phenomena in Hessdalen valley, Norway.  

NASA Astrophysics Data System (ADS)

The transient luminous phenomena's in Hessdalen valley has at least been observed for 200 years, since 1811, when the priest Jacob T. Krogh did the first written documentation. The valley is located in the middle of Norway, isolated and with sub arctic climate. The former mining district has no more than 140 inhabitants, and the deep mines are closed and filled with water. The valley has been under scientific surveillance since 1998 when the first automated and remote controlled observatory was put into action. Today a Norwegian, Italian and French collaboration runs 3 different research stations inside the valley. Each year a scientific field campaign establishes 4 temporary bases in the mountains, and up to 100 students and researchers man these bases for up to 14 days in september when the moon is down. The Hessdalen phenomena is not easy to detect, and approximately only 20 observations is done each year. The work done the last 14 years suggests that the phenomenon has different states, at least 6 detected so far. The states are so different that to se a coupling between them is difficult. New work done into dusty plasma physics suggest that the different phenomena's may be of the same origin, since the ionized grains of dusty plasma can change states from weakly coupled (gaseous) to crystalline, altering shape/formation and leading to different phenomena. Optical spectrometry from 2007 suggested that the luminous phenomena consisted of burning air and dust from the valley. Work done by G.S Paiva and C.A Taft suggests that radon decay from closed mines may be the mechanism that ionizes dust and triggers this phenomena. The 6 different main states of the Hessdalen phenomena, Doublet, Fireball, Plasma ray, Dust cloud, Flash and Invisible state is described and discussed. Investigation of the atmosphere inside the Hessdalen valley with low frequency directional RADAR, reveals large areas of ionized matter, giving a reflecting area big enough to saturate the input of the radar receiver. Together with long living time, ground analysis and radio active measurements, do not support the radon decay theory, and other forms of ionizing mechanisms must be investigated. The phenomenon's energy source is still not revealed, and the question of internal or external power source is also unexplained.

Hauge, B. G.; Montebugnoli, S.

2012-04-01

249

Natural phenomena hazards, Hanford Site, south central Washington  

SciTech Connect

This document presents the natural phenomena hazard (NPH) loads for use in implementing DOE Order 5480.28, Natural Phenomena Hazards Mitigation, at the Hanford Site in south-central Washington State. The purpose of this document is twofold: (1) summarize the NPH that are important to the design and evaluation of structures, systems, and components at the Hanford Site; (2) develop the appropriate natural phenomena loads for use in the implementation of DOE Order 5480.28. The supporting standards, DOE-STD-1020-94, Natural Phenomena Hazards Design and Evaluation Criteria for Department of Energy Facilities (DOE 1994a); DOE-STD-1022-94, Natural Phenomena Hazards Site Characteristics Criteria (DOE 1994b); and DOE-STD-1023-95, Natural Phenomena Hazards Assessment Criteria (DOE 1995) are the basis for developing the NPH loads.

Tallman, A.M.

1996-04-16

250

Astrophysical phenomena related to supermassive black holes  

NASA Astrophysics Data System (ADS)

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

Pott, Jörg-Uwe

2006-12-01

251

Pathways toward understanding Macroscopic Quantum Phenomena  

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

252

Infrared characteristic radiation of water condensation and freezing in connection with atmospheric phenomena  

Microsoft Academic Search

This paper considers the emission of infrared characteristic radiation during the first order phase transitions of water (condensation and crystallization). Experimental results are analyzed in terms of their correspondence to the theoretical models. These models are based on the assumption that the particle's (atom, molecule, or cluster) transition from the higher energetic level (vapor or liquid) to a lower one

Vitali A. Tatartchenko

2010-01-01

253

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

NASA Astrophysics Data System (ADS)

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.

Teodorani, M.

2009-12-01

254

Characteristics of aerosol phenomena in Martian atmosphere from KRFM experiment data  

NASA Astrophysics Data System (ADS)

On the basis of photometric measurements both constant dust haze and high altitude ice clouds on the equatorial part of Mars were analyzed. The imaginary part of the refraction index k from 0.01 to 0.03 at 315 nm and from 0.005 to 0.01 at 550 nm was estimated for constant dust haze, using Mie theory for spherical particles. It is noted that these values for k are a few times higher than those obtained by the laboratory tests of terrestrial analogs including basalt, andesite, and montmorillonite. Two possible explanations for this phenomenon are presented, citing the irregular shape of particles and/or the presence of some more absorbing substances as potentially influential.

Moroz, V. I.; Petrova, E. V.; Ksanfomality, L. V.; Ganpantzerova, O. F.; Goroshkova, N. V.; Zharkov, A. V.; Nikitin, G. E.; Esposito, L.; Bibring, J.-P.; Combes, M.; Soufflot, A.

1991-02-01

255

The atmosphere of Uranus  

Microsoft Academic Search

Current knowledge of the atmosphere of Uranus is reviewed and specific objectives are suggested for satellite missions to Uranus. The anomalous composition of Uranus makes determinations of its atmospheric composition particularly valuable for testing theories of solar system evolution. The weakness of its atmospheric heating makes the determination of its atmospheric structure and dynamics particularly valuable for testing theories of

P. H. Stone

1975-01-01

256

Venus Atmospheric Dynamics  

Microsoft Academic Search

Over the last four decades, we have learned much about the atmosphere of Venus and its circulation through earth-based, spacecraft orbiters and entry probes and even balloons. However, our understanding of the processes maintaining the atmospheric circulation of the atmosphere is poor. We have discovered every where we have measured, the atmosphere moves in the same direction as the underlying

S. S. Limaye

2004-01-01

257

Cooperative phenomena in strongly correlated electron systems  

NASA Astrophysics Data System (ADS)

In this review we present results of our theoretical study of cooperative phenomena in strongly correlated electron systems obtained within various generalizations of the Falicov-Kimball model. The primary goal of this study was to identify crucial interactions that lead to the stabilization of the specific cooperative phenomenon, and then try to elaborate its comprehensive microscopic description. The main attention is devoted to a discussion of valence and metal-insulator transitions, formation of charge and spin ordering, electronic ferroelectricity, itinerant ferromagmetism and mechanisms leading to their stabilization. Among the major mechanisms we examine the effect of local and nonlocal Coulomb interaction between localized and itinerant electrons, local and nonlocal hybridization, long-range and correlated hopping of itinerant electrons and spin-dependent interaction between localized and itinerant electrons, both for zero and nonzero temperatures, as well as for doped and undoped systems. Finally, the relevance of resultant solutions for a description of rare-earth and transition-metal compounds is discussed.

Farkašovský, Pavol

2010-10-01

258

Anomalous Nuclear Phenomena Assocoated with Ultrafast Processes  

NASA Astrophysics Data System (ADS)

Quantum physics predicts the existence of an underlying sea of zero-point energy at every point in the universe. A minority of physicists accept it as real energy which we cannot directly sense since it is the same everywhere, even inside our bodies and measuring devices. If the zero-point energy is real, there is the possibility that it can be tapped as a source of power or be harnassed to generate a propulsive force for space travel. However if some asymmetric variation of the Casimir force could be identified one could in effect sail through space as if propelled by a kind of quantum fluctuation wind. In our previous papers, anomalous excess heat and localized nuclear reactions on the surface of electrodes in electrolysis cells have been observed. A physical model of transient vortex dynamics with torsion coherence with the zero point energy has been proposed by Xingliu Jiang based on the ultrafast processes of triple phases area of tip effect on the electrode surface. Considering the large equiverlent capacitance of electrochemical double layer, it is presumed that the double layer can exhibit nonlinear electrical response with spatial and temporal variations confined to microscopic areas by tip effect. Experimental results of transient processes with ultrafast phenomena with nanosecond duration in electrical discharge systems including electrolysis cells and corona discharge have been presented.

Jiang, Xingliu; Zhou, Xiaoping; Liu, Chun; Wang, Liying; Zhang, Zhongliang

2007-04-01

259

Rotary kilns - transport phenomena and transport processes  

SciTech Connect

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.

Boateng, A.

2008-01-15

260

Near Critical Phenomena in Laminar Boundary Layers  

NASA Astrophysics Data System (ADS)

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 .

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

261

The Monitoring of Transient Lunar Phenomena  

NASA Astrophysics Data System (ADS)

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.

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

2011-05-01

262

Transition phenomena in unstably stratified turbulent flows.  

PubMed

We study experimentally and theoretically the transition phenomena caused by external forcing from Rayleigh-Bénard convection with large-scale circulation (LSC) to the limiting regime of unstably stratified turbulent flow without LSC, where the temperature field behaves like a passive scalar. In the experiments we use the Rayleigh-Bénard apparatus with an additional source of turbulence produced by two oscillating grids located near the sidewalls of the chamber. When the frequency of the grid oscillations is larger than 2 Hz, the LSC in turbulent convection is destroyed, and the destruction of the LSC is accompanied by a strong change of the mean temperature distribution. However, in all regimes of the unstably stratified turbulent flow the ratio [(?{x}?{x}T)²+(?{y}?{y}T)² + (?{z}?{z}T)²]/ varies slightly (even in the range of parameters where the behavior of the temperature field is different from that of the passive scalar). Here ?{i} are the integral scales of turbulence along the x,y,z directions, and T and ? are the mean and fluctuating parts of the fluid temperature. At all frequencies of the grid oscillations we have detected long-term nonlinear oscillations of the mean temperature. The theoretical predictions based on the budget equations for turbulent kinetic energy, turbulent temperature fluctuations, and turbulent heat flux, are in agreement with the experimental results. PMID:21517582

Bukai, M; Eidelman, A; Elperin, T; Kleeorin, N; Rogachevskii, I; Sapir-Katiraie, I

2011-03-03

263

Solar Phenomena Associated With EIT Waves  

NASA Astrophysics Data System (ADS)

Observations with the Extreme Ultraviolet Imaging Telescope (EIT) on SOHO revealed the existence of transient waves which appear to propagate across the disk from a localized starting point. These EIT waves may be the coronal counterpart of previously discovered Moreton waves. Moreton waves have long been thought to be associated with solar flares, though this may have been because flares are more easily observed than other phenomena, such as Coronal Mass Ejections. EIT waves are observed much more often than Moreton waves, though this may also be due to detection efficiency. In this study, we hope to gain a better understanding of EIT waves, and in particular their initiation, through their relationship to other solar events. This study uses a complete catalog of EIT waves observed from March, 1997 to June, 1998; a period in which 175 waves were found. For each wave, the following ancillary data sets were examined for co-temporal and co-spatial events: GOES X-ray Monitor, LASCO Coronagraph, and Type II radio burst data. EIT waves are classified according to a system which measures the reliability of the existence of the event. We investigate the rate at which each class of EIT wave is associated with flares, CMEs and Type II events. Data are further divided into limb and disk events in order to correct for detection efficiency and biases. An investigation of EUV dimmings is also included as they offer clues to the relationship between EIT waves, flares and CME's.

Myers, D. C.; Biesecker, D. A.; Thompson, B. J.; Vourlidas, A.

2001-05-01

264

Fluctuation phenomena in neurological local field potentials  

NASA Astrophysics Data System (ADS)

The study of noise and fluctuations has proven useful in a wide variety of disordered systems, from disordered condensed matter systems to noisy biological systems. Neurological signals termed local field potentials are characterized by apparently random fluctuations interspersed with periods of clear oscillatory activity. Numerous mathematical theories have been developed that describe the power spectrum that results from different fluctuation phenomena. Several of these theories are presented with discussions of how they may apply to local field potentials in the brain. Experiments and simulations are proposed that could help to clarify specific aspects of the fluctuation origins of local field potentials. Given long time series of neurological voltage fluctuations, it can be difficult to detect the occurrence of oscillatory activity. An analytical method is presented to identify the presence of oscillations within a signal. This method is verified through simulations and experiments on signals with known oscillations. Using this method, a previously unknown oscillation is detected, termed gamma50, that is recorded in the striatum of awake, behaving rats. The gamma50 signal is characterized by short bursts of coherent 50 Hz oscillations, and is found to be correlated with the initiation of movement. Preliminary experiments were conducted to identify the origin of gamma50 events. Data from these experiments is discussed along with remaining open research questions and future directions.

Masimore, Beth

265

Meteorological phenomena affecting the presence of solid particles suspended in the air during winter  

NASA Astrophysics Data System (ADS)

Winter is not traditionally considered to be a risky season for people who suffer from pollen allergies. However, increasing numbers of people are showing symptoms in winter. This prompted our investigation into the levels of solid material in the air, and some of the meteorological phenomena that allow their accumulation. This study showed a possible relationship between the phenomenon of thermal inversion, which occurs when very low temperatures, cloudless skies and atmospheric calms coincide, and an increase in the concentration of solid material in the atmosphere. Frequently, this situation is associated with other predictable phenomena such as fog, dew and frost. This may allow a warning system to be derived for urban pollution episodes. The effect caused by parameters such as wind and rainfall was also analysed. Solid material was differentiated into non-biological material from natural and non-natural sources (e.g. soot, dust, sand, diesel exhaust particles, partially burnt residues) and biological material. The latter mainly comprises pollen grains and fungal spores. Owing to its abundance and importance as a causal agent of winter allergies, Cupressaceae pollen was considered separately.

Cariñanos, P.; Galán, C.; Alcázar, P.; Dominguez, E.

266

The phenomenology of life phenomena--in a nursing context.  

PubMed

The purpose of this article is to describe and develop knowledge about life phenomena in a life-philosophical and nursing context. Knowledge about life phenomena is part of a care-ethical understanding with a focus on relations. Life phenomena are to be understood as a generalized label for the various phenomena which are given with human existence. The Danish life philosophical tradition with the perspective of life as experienced has something to say in relation to a further refinement of the phenomenology of life phenomena. The refinement will be described as an ethical and existential understanding of the phenomena of nursing. The first part of the article takes a philosophical approach to the phenomenology of life phenomena. It attempts to locate life phenomena in relation to, respectively, needs, senses, and feelings. In order to maintain an overview, the attempt is made to separate needs, senses, and feelings, although in real life these are closely interwoven. The article also describes philosophy and life phenomena in relation to nursing as an empirical field. In nursing there is a risk that life phenomena become invisible to those whose task is to help the ill person adjust to a new life situation. For the nurse, it will be a continuing task, never completed, to develop a sensory-based, situation-determined attention to the patient. And the nurse must be continually aware of whether mere 'need-oriented' nursing is controlling her professional actions as a nurse. Taking a point of departure in the nurse's sensory, situationally determined attention, the last part of the article focuses on needs, senses, and feelings in connection with the nurse being able to direct her attention to the patient's life phenomena. PMID:16965305

Delmar, Charlotte

2006-10-01

267

Atmospheric corrosion of lithium electrodes  

SciTech Connect

Atmospheric corrosion of lithium during lithium-cell assembly and the dry storage of cells prior to electrolyte fill has been found to initiate lithium corrosion pits and to form corrosion products. Scanning Electron Microscopy (SEM) was used to investigate lithium pitting and the white floccullent corrosion products. Electron Spectroscopy for Chemical Analysis (ESCA) and Auger spectroscopy in combination with X-ray diffraction were used to characterize lithium surfaces. Lithium surfaces with corrosion products were found to be high in carbonate content indicating the presence of lithium carbonate. Lithium electrodes dry stored in unfilled batteries were found to contain high concentration of lithium flouride a possible corrosion product from gaseous materials from the carbon monofluoride cathode. Future investigations of the corrosion phenomena will emphasize the effect of the corrosion products on the electrolyte and ultimate battery performance. The need to protect lithium electrodes from atmospheric exposure is commonly recognized to minimize corrosion induced by reaction with water, oxygen, carbon dioxide or nitrogen (1). Manufacturing facilities customarily limit the relative humidity to less than two percent. Electrodes that have been manufactured for use in lithium cells are typically stored in dry-argon containers. In spite of these precautions, lithium has been found to corrode over a long time period due to residual gases or slow diffusion of the same into storage containers. The purpose of this investigation was to determine the nature of the lithium corrosion.

Johnson, C.J.

1981-10-01

268

Quantum phenomena in condensed phase systems  

NASA Astrophysics Data System (ADS)

This thesis develops mixed quantum-classical methods to model dynamical nonequilibrium quantum phenomena in condensed phase systems, and also explores properties of 2-d systems near a quantum critical point using field theoretic techniques and purely classical simulation. Mixed quantum-classical methods involve dividing the system into a quantum sub-system coupled to a classical bath, which is useful for examining the dynamics of systems in the condensed phase since the full quantum treatment of a large number of degrees of freedom is often computationally infeasible. Although the bath is treated classically, its coupling to the quantum system precludes a Newtonian description. We implement an approach that uses the quantum-classical Liouville equation to propagate the quantum subsystem density matrix, which results in an ensemble of surface-hopping trajectories. We test this method on model systems and compare with a linearized path-integral approach. We also develop a novel approach to propagating the reduced density matrix that incorporates ideas from both methods while maintaining the ease of implementation of linearized methods. We study the 2-d spin gap antiferromagnet, piperanzium hexachlorodicuprate (PHCC) near a quantum critical point, where the spin gap is closed by an applied magnetic field, and excitations behave like Sz = 1 bosons. Using field theoretic techniques, we find that the temperature dependence of the propagating mode energy is successfully described by a self-consistent Hartree-Fock theory of spin excitations. We also investigate the thermally excited 2-d dilute Bose gas near a quantum critical point, which can be used to obtain the dynamic spectrum of PHCC and other 2-d antiferromagnets. While the pairwise interactions between bosons are weak, we find that the collective properties pose a strong coupling problem (in contrast to the 3-d case). We describe these interactions effectively with a classical model.

Dunkel, Emily Rebecca

269

Field dependence, suggestibility and belief in paranormal phenomena  

Microsoft Academic Search

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.

Andreas Hergovich

2003-01-01

270

Interfacial Phenomena in the Filtration\\/Separation of Petroleum Products  

Microsoft Academic Search

The increased dieselization of the internal combustion engine and other energy related considerations are the impetus for higher performance, longer life petroleum product filters. A better understanding of the role of interfacial phenomena, in the non-aqueous filtration applications, is needed for improved products. This review paper focuses on the effect of interfacial phenomena in the coalescence and separation of water

Rajan A. Jaisinghani

1983-01-01

271

Phenomena of liquid drop impact on solid and liquid surfaces  

Microsoft Academic Search

The fluid dynamic phenomena of liquid drop impact are described and reviewed. These phenomena include bouncing, spreading and splashing on solid surfaces, and bouncing, coalescence and splashing on liquid surfaces. Further, cavitation and the entrainment of gas into an impacted liquid may be observed. In order to distinguish properly between the results of different experiments different impact scenarios are discussed.

Martin Rein

1993-01-01

272

Cold spray deposition: Significance of particle impact phenomena  

Microsoft Academic Search

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

Sergei Vladimirovich Klinkov; Vladimir Fedorovich Kosarev; Martin Rein

2005-01-01

273

Orthogonalization of vectors and its relation to cognitive phenomena  

NASA Astrophysics Data System (ADS)

A geometrical view of all known orthogonalization procedures is taken to understand their distinctive features and the inter-connections between them. Curious new information is gained which is also found useful to understand the basis of certain cognitive phenomena, like discrimination and categorisation. A spin-glass like neural network model has been introduced to understand the cognitive phenomena.

Srivastava, Vipin

274

FOREWORD: Electromagnetic Phenomena and Health - A Continuing Controversy?  

Microsoft Academic Search

A variety of natural electromagnetic phenomena - from electrostatic and magnetostatic fields to radiowaves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma radiation - may influence human health and wellbeing (by their presence, intensity or absence) in a number of diverse ways. Some artificially created electromagnetic phenomena may also directly and\\/or indirectly influence biological functioning, though the levels and extent

Isaac A. Jamieson; Paul Holdstock

2010-01-01

275

Role of surface phenomena in chemmotology of oils  

Microsoft Academic Search

UDC 620.197.3 Surface phenomena are among the most widely distributed natural processes that determine human activity and its interaction with the environment. These phenomena play an extremely important role in chemmotology. Surface processes are manifested in the action of fuels, lubricants, and specialty fluids, the results of which determine the level of surface properties of these products. The driving force

V. L. Lashkhi; N. N. Zakharova

1991-01-01

276

Psychic phenomena following near-death experiences: An Australian study  

Microsoft Academic Search

This study examines the incidence of reports of psychic phenomena and associated beliefs both before and after the near-death experience (NDE). The near-death experiencers interviewed reported no more psychic phenomena before the NDE than the general population. There was a statistically significant increase following the NDE in the incidence of 14 of 15 items examined.

Cherie Sutherland

1989-01-01

277

PREFACE: XI Latin American Workshop on Nonlinear Phenomena  

Microsoft Academic Search

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

Celia Anteneodo; Marcos G. E. da Luz

2010-01-01

278

Modeling of evaporation and oxidation phenomena in plasma spraying of metal powders  

NASA Astrophysics Data System (ADS)

Plasma spraying of metals in air is usually accompanied by evaporation and oxidation of the sprayed material. Optimization of the spraying process must ensure that the particles are fully molten during their short residence time in the plasma jet and prior to hitting the substrate, but not overheated to minimize evaporation losses. In atmospheric plasma spraying (ASP), it is also clearly desirable to be able to control the extent of oxide formation. The objective of this work to develop an overall mathematical model of the oxidization and volatilization phenomena involved in the plasma-spraying of metallic particles in air atmosphere. Four models were developed to simulate the following aspects of the atmospheric plasma spraying (APS) process: (a) the particle trajectories and the velocity and temperature profiles in an Ar-H 2 plasma jet, (b) the heat and mass transfer between particles and plasma jet, (c) the interaction between the evaporation and oxidation phenomena, and (d) the oxidation of liquid metal droplets. The resulting overall model was generated by adapting the computational fluid dynamics code FIDAP and was validated by experimental measurements carried out at the collaborating plasma laboratory of the University of Limoges. The thesis also examined the environmental implications of the oxidization and volatilization phenomena in the plasma spraying of metals. The modeling results showed that the combination of the standard k-s model of turbulence and the Boussinesq eddy-viscosity model provided a more accurate prediction of plasma gas behavior. The estimated NOx generation levels from APS were lower than the U.S.E.P.A. emission standard. Either enhanced evaporation or oxidation can occur on the surface of the metal particles and the relative extent is determined by the process parameters. Comparatively, the particle size has the greatest impact on both evaporation and oxidation. The extent of particle oxidation depends principally on gas-liquid oxidation. The convection due to recirculating flow of liquid within the metal droplet (Hill's vortex) dominates the mass transfer of oxygen after the metal particles become molten. This study showed that the behavior of evaporation and oxidation of metal particles in atmospheric plasma spraying can be predicted and the process parameters can be optimized to reduce the evaporation and/or oxidation of metal particles in industrial applications of plasma spraying.

Zhang, Hanwei

279

Influence of solar activity on the lower atmosphere state  

NASA Astrophysics Data System (ADS)

This paper briefly reviews modern ideas about plausible mechanisms of influence of solar activity on the lower atmosphere state and weather. The possible reasons for the disturbances in the lower atmosphere are as follows: (1) variations in solar irradiance, (2) changes in the global electric circuit parameters caused by variations in cosmic ray fluxes, (3) variations in the conditions of propagation and dissipation energy of planetary waves in the atmosphere, and (4) changes in the atmospheric transparency and cloudiness are considered. Specific features of development of individual (with duration of several days) disturbances in the lower atmosphere observed during Forbush decreases of galactic cosmic rays and solar proton events are discussed. It is concluded that at latitudes of 55o-70o the disturbances considered are mainly due to variations in atmospheric transparency and cloudiness. Data on cyclic variations of the lower atmosphere state and their connection with variations in solar activity, atmospheric transparency, volcano eruptions, and other geophysical phenomena are analyzed. In conclusion, some unresolved problems of morphology of atmospheric disturbances are formulated.

Pudovkin, M. I.

2004-12-01

280

Estimation of the atmospheric corrosion on metal containers in industrial waste disposal.  

PubMed

Solid industrial waste are often stored in metal containers filled with concrete, and placed in well-aerated warehouses. Depending on meteorological conditions, atmospheric corrosion can induce severe material damages to the metal casing, and this damage has to be predicted to achieve safe storage. This work provides a first estimation of the corrosivity of the local atmosphere adjacent to the walls of the container through a realistic modeling of heat transfer phenomena which was developed for this purpose. Subsequent simulations of condensation/evaporation of the water vapor in the atmosphere were carried out. Atmospheric corrosion rates and material losses are easily deduced. For handling realistic data and comparison, two different meteorological contexts were chosen: (1) an oceanic and damp atmosphere and (2) a drier storage location. Some conclusions were also made for the storage configuration in order to reduce the extent of corrosion phenomena. PMID:11489528

Baklouti, M; Midoux, N; Mazaudier, F; Feron, D

2001-08-17

281

Solidification phenomena in metal matrix nanocomposites  

NASA Astrophysics Data System (ADS)

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.

de Cicco, Michael Peter

282

Role of defects in the supersolid phenomena  

NASA Astrophysics Data System (ADS)

We investigate the role of topological defects, particularly dislocations, in the observed phenomena of supersolidity---a state of matter with simultaneous long range crystalline order and superfluid behavior. First, we determine bound state solutions of the 2D Schrodinger equation with a dipole potential originating from the elastic effects of a single edge dislocation. Along with a variational estimate of the ground state energy, we numerically solve the eigenvalue problem and calculate the energy spectrum using methods of exact diagonalization and basis expansion. A comparison of the behavior of the calculated energy spectrum and that obtained from semiclassical considerations is briefly discussed. The quantum mechanics of the inverse square screw dislocation potential is briefly discussed and the ground state energy values calculated for different cut-offs to the potential. We next propose an explanation for the heat capacity peak observed by Lin et al. [Nature 449, 1025 (2007)], by developing a lattice gas model of desorption (absorption) of 3He impurities from dislocations in solid 4He. The thermodynamics of the model is discussed and the associated heat capacity is calculated. We find that for various 3He concentrations and suitable dislocation densities the heat capacity shows quantitative agreement with the experiment, suggesting that the specific heat peak observed in the experiments may be due to a Schottky anomaly. Finally, within a phenomenological Landau theory, we study the effect of an edge dislocation in promoting superfluidity in a Bose crystal. We couple the elastic strain field of the dislocation to the superfluid density, and use a linear analysis to show that superfluidity nucleates on the dislocation before occurring in the bulk of the solid. Moving beyond the linear analysis, we develop a systematic perturbation theory in the weakly nonlinear regime, and use this method to integrate out transverse degrees of freedom and derive a one-dimensional Landau equation for the superfluid order parameter. We then extend our analysis to a network of dislocation lines, and derive an XY model for the dislocation network by integrating over fluctuations in the order parameter. Our results show that the ordering temperature for the network has a sensitive dependence on the dislocation density, consistent with numerous experiments that find a clear connection between the sample quality and the supersolid response.

Goswami, Debajit

283

Saving the Phenomena in Medieval Astronomy  

NASA Astrophysics Data System (ADS)

Aristotle's theory of motion is based on two principles: (1) all motion to either from the midpoint of the Earth, toward it, or around it, and (2) circular motion must proceed around an immovable point. On this view, the heavenly bodies are individual points of light carried around by a series of concentric spheres rotating at a constant pace around the midpoint of the Earth. But even in Aristotle's day, it was known that this theory had a great deal of difficulty accounting for planetary motion. Ptolemy's alternative was to introduce epicycles and eccentric orbits, thus denying Aristotle's view of natural motion. There was no doubt that Ptolemy's predictions were far better than Aristotle's. But for the medievals, Aristotle's theory made better intuitive sense. Moreover, Ptolemy's theory raised the question of how one sphere could pass through another. What to do? The solution of Moses Maimonides (1138-1204) was to say that it is not the job of the astronomer to tell us how things actually are but merely to propose a series of hypotheses that allow us to explain the relevant data. This view had obvious theological implications. If astronomy could explain planetary motion in an acceptable way, there was reason to believe that the order or structure of the heavens is what it is by necessity. This suggests that God did not exercise any degree of choice in making it that way. But if astronomy cannot explain planetary motion, the most reasonable explanation is that we are dealing with contingent phenomena rather than necessary ones. If there is contingency, there is reason to think God did exercise a degree of choice in making the heavens the way they are. A God who exercises choice is much closer to the God of Scripture. Although Galileo changed all of this, and paved the way for a vastly different view of astronomy, the answer to one set of questions raises a whole different set. In short, the heavenly motion still poses ultimate questions about God, existence, and the origin of the universe.

Seeskin, K.

2011-06-01

284

Sub-photosphere to Solar Atmosphere Connection  

NASA Astrophysics Data System (ADS)

Magnetic fields extend from the solar interior through the atmosphere. The formation and evolution of active regions can be studied by measuring subsurface flows with local helioseismology. The emergence of magnetic flux from the solar convection zone is associated with acoustic perturbation signatures. In near-surface layers, the average dynamics can be determined for emerging regions. MHD simulations of the emergence of a twisted flux tube show how magnetic twist and free energy are transported from the interior into the corona and the dynamic signatures associated with such transport in the photospheric and sub-photospheric layers. The subsurface twisted flux tube does not emerge into the corona as a whole in emerging active regions. Shear flows at the polarity inversion line and coherent vortical motions in the subsurface flux tubes are the major means by which twist is transported into the corona, leading to the formation of sigmoid-shaped coronal magnetic fields capable of driving solar eruptions. The transport of twist can be followed from the interior by using the kinetic helicity of subsurface flows as a proxy of magnetic helicity; this quantity holds great promise for improving the understanding of eruptive phenomena. Waves are not only vital for studying the link between the solar interior and the surface but for linking the photosphere with the corona as well. Acoustic waves that propagate from the surface into the magnetically structured, dynamic atmosphere undergo mode conversion and refraction. These effects enable atmospheric seismology to determine the topography of magnetic canopies in the solar atmosphere. Inclined magnetic fields lower the cut-off frequency so that low frequency waves can leak into the outer atmosphere. Recent high resolution, high cadence observations of waves and oscillations in the solar atmosphere, have lead to a renewed interest in the potential role of waves as a heating mechanism. In light of their potential contribution to the heating of the solar atmosphere, some of the recent observations of waves and oscillations and ongoing modelling efforts are reviewed.

Komm, Rudolf; De Moortel, Ineke; Fan, Yuhong; Ilonidis, Stathis; Steiner, Oskar

2013-10-01

285

Numerical investigations on some lightning phenomena  

NASA Astrophysics Data System (ADS)

We currently use and develop a cylindrical coupled radiation-hydrodynamic code which contains over 600 chemical reaction and ionization equations that are essential for the detailed multi-spectral predication of air opacity. These hydrodynamic methods and detailed chemistry allow us simulating the lightning return stroke, which is the radiating shock wave of hot ionized air produced by the electrical discharge. Our longterm goals are (i) the understanding the complex chemical reactions (e.g. formation of NOx, destruction of ozone, etc.) that occur during a lightning discharge and their cumulative effect on atmospheric chemistry and composition, and (ii) determining the multi-spectral radiation signature of a lightning discharge for different altitudes. We will discuss some of the lightning signatures we simulate. In addition, we have coupled to our code a simplified Maxwell system which allows resolving the discharge growth and the air plasma formation in the return stroke. We will show how we simulate the creation of the lightning channel followed by its expansion.

Ripoll, Jean-Francois; Jeffery, Christoffer; Colestock, Patrick; Zinn, John

2006-11-01

286

DEMETER Observations of Equatorial Plasma Depletions and Related Ionospheric Phenomena  

NASA Astrophysics Data System (ADS)

DEMETER, the first micro-satellite of the CNES MYRIAD program, was launched from Baikonour on June 29, 2004 on a nearly circular, quasi helio-synchronous polar orbit at ~ 715 km altitude. The DEMETER mission focuses primarily on the search for a possible coupling between seismic activity and ionospheric disturbances as well as on the effects of natural phenomena such as tropospheric thunderstorms and man-made activities on the ionosphere. The scientific payload provides fairly complete measurements of the ionospheric plasma, energetic particles above ~ 70 keV, and plasma waves, up to 20 kHz for the magnetic and 3.3 MHz for the electric components. Several studies related to space weather and ionospheric physics have been conducted over the past years. Following a brief description of the payload and the satellite modes of operation, this presentation will focus on a set of results that provide a new insight into the physics of instabilities in the night-time equatorial ionosphere. The observations were performed during the major magnetic storm of November 2004. Deep plasma depletions were observed on several night-time passes at low latitudes characterized by the decrease of the plasma density by nearly 3 orders of magnitude relative to the undisturbed plasma, and a significant abundance of molecular ions. These features can be best interpreted as resulting from the rise of the F-layer above the satellite altitude over an extended region of the ionosphere. In one of the passes, DEMETER was operated in the Burst mode and the corresponding high resolution data allowed for the discovery of two unexpected phenomena. The first one is the existence of high intensity monochromatic wave packets at the LH frequency that develop during the decay phase of intense bursts of broadband LH turbulence. The broadband LH turbulence is triggered by whistlers emitted by lightning from atmospheric thunderstorms beneath the satellite. The second unexpected feature is the detection of a population of super-thermal ionospheric ions with a density of about 2-3% of the thermal ion population. The super- thermal ions appeared to be heated to temperatures of a few eV at times when LH turbulence and monochromatic wave packets are observed while the temperature of the core ion population is not affected. High time resolution plasma density measurements show the presence of strong small scale plasma irregularities in the depletions that scatter the high amplitude whistler waves and may lead to the development of strong LH turbulence and of monochromatic wave packets. The ensuing interaction between these waves and the ambient ions may lead to the formation of a super-thermal tail in the ion distribution function. Ion acceleration by LH turbulence and solitary waves is a commonly observed phenomenon along auroral magnetic field lines but, to our knowledge, this is the first time that a similar process has been observed in the equatorial ionosphere. These findings exemplify a novel coupling mechanism between the troposphere and the ionosphere: Under highly disturbed conditions at times of magnetic storms, part of the energy released by lightning and radiated as whistlers can dissipate in the equatorial ionosphere and produce super-thermal ion populations.

Berthelier, J.; Malingre, M.; Pfaff, R.; Jasperse, J.; Parrot, M.

2008-12-01

287

Physics of the Sun and its Atmosphere  

NASA Astrophysics Data System (ADS)

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.

Dwivedi, B. N.; Narain, U.

288

Atmospheric Transport of Radionuclides  

SciTech Connect

The purpose of atmospheric transport and diffusion calculations is to provide estimates of concentration and surface deposition from routine and accidental releases of pollutants to the atmosphere. This paper discusses this topic.

Crawford, T.V.

2003-03-03

289

Atmospheric Models for Aerocapture.  

National Technical Information Service (NTIS)

There are eight destinations in the solar System with sufficient atmosphere for aerocapture to be a viable aeroassist option - Venus, Earth, Mars, Jupiter, Saturn and its moon Titan, Uranus, and Neptune. Engineering-level atmospheric models for four of th...

C. G. Justus A. L. Duvall V. W. Keller

2004-01-01

290

Global Atmospheric Aerosol Modeling.  

National Technical Information Service (NTIS)

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 g...

J. Hendricks M. Righi V. Aquila

2012-01-01

291

Simulation of the atmospheric thermal circulation of a martian volcano using a mesoscale numerical model.  

PubMed

Mesoscale (<100 km) atmospheric phenomena are ubiquitous on Mars, as revealed by Mars Orbiter Camera images. Numerical models provide an important means of investigating martian atmospheric dynamics, for which data availability is limited. But the resolution of general circulation models, which are traditionally used for such research, is not sufficient to resolve mesoscale phenomena. To provide better understanding of these relatively small-scale phenomena, mesoscale models have recently been introduced. Here we simulate the mesoscale spiral dust cloud observed over the caldera of the volcano Arsia Mons by using the Mars Regional Atmospheric Modelling System. Our simulation uses a hierarchy of nested models with grid sizes ranging from 240 km to 3 km, and reveals that the dust cloud is an indicator of a greater but optically thin thermal circulation that reaches heights of up to 30 km, and transports dust horizontally over thousands of kilometres. PMID:12384691

Rafkin, Scot C R; Sta Maria, Magdalena R V; Michaels, Timothy I

2002-10-17

292

Atmosphere, Weather, and Climate  

Microsoft Academic Search

The fourth edition of this book, first published in 1968, is to be welcomed. It is widely used in geography courses in schools and universities and has had considerable success in introducing, with the minimum of mathematics, synoptic and dynamic meterology and climatology into such courses. Its chapters cover atmospheric composition and energy, atmospheric moisture, atmospheric motion, air masses, fronts

J. T. Houghton

1984-01-01

293

Atmospheric Budget of Acetone  

Microsoft Academic Search

The atmospheric budget and distribution of acetone are investigated by using best a priori estimates of sources and sinks to constrain a global 3-dimensional atmospheric model simulation, and then using atmospheric observations from 14 surface sites and 5 aircraft missions to improve these estimates through an inversion analysis. Matching the observed acetone concentrations over the South Pacific requires a large

D. J. Jacob; B. D. Field; Emily M. Jin; Isabelle Bey; Qinbin Li; J. A. Logan; R. M. Yantosca; H. B. Singh

2001-01-01

294

Atmospheric budget of acetone  

Microsoft Academic Search

The atmospheric budget and distribution of acetone are investigated by using a priori estimates of sources and sinks to constrain a global three-dimensional atmospheric model simulation and then using atmospheric observations from 14 surface sites and 5 aircraft missions to improve these estimates through an inversion analysis. Observations over the South Pacific imply a large photochemical marine source of acetone,

Daniel J. Jacob; Brendan D. Field; Emily M. Jin; Isabelle Bey; Qinbin Li; Jennifer A. Logan; Robert M. Yantosca; Hanwant B. Singh

2002-01-01

295

Mixed burden softening and melting phenomena  

NASA Astrophysics Data System (ADS)

The blast furnace (BF) will remain the major iron producing unit for the foreseeable future. The cohesive zone, where ferrous materials soften and melt, affects the productivity of the BF. This research was focused on expanding the current understanding of the mechanism of softening and melting of the ferrous materials. The other objective of this project was to examine the potential use of direct reduced iron (DRI) and hot briquetted iron (HBI) as the BF burden. The materials used in this study were DRI, HBI, lump iron ore and pellets. A wide variety of experimental procedures were employed to completely understand the process phenomena. The softening and melting (SM) experiments were conducted under load and X-Ray fluoroscopy was used to visualize the process. The results of these experiments were conducive in determining a suitable mechanism of softening and melting of the burden. For single burdens of DRI and HBI, softening occurred when metal began to melt. For mixed burdens of DRI and pellets/lump ore, the initial deformation was not affected by DRI; however DRI dominated as the temperature increased and melting occurred only when DRI melted. Melt dripping was observed at temperatures close to meltdown. A FactSage slag model was used to obtain the evolution of liquid with temperature. It was compared with the bed shrinkage which indicated that the most likely reason of the softening of the burden is the deformation of solid, phases, especially iron. The bulk SM experiments were interrupted at temperatures of interest and samples were examined for the morphological changes. These experiments were instrumental in studying the burden interaction at different stages during softening and melting of the burden. In addition, in separate experiments (without load), the melting structure of DRI/HBI samples was studied. The results of these experiments were expanded to include viscosity, surface energy and deformation rate calculations which were helpful in understanding the melt exudation phenomenon. The microstructure of the materials showed a transition from heterogeneous to homogenous state with increasing temperatures. The melt dripping was predominantly observed in olivine fluxed pellets. The exuded slag was primarily composed of alkali rich phase which was found least viscous amongst all types of slags present in this system. The viscosity of the liquid and the structure of metallic shell facilitated the melt exudation from the burden. In addition, the liquid filled the iron shell and coarsened its structure. Based on the metallographic examination of the samples a mechanism of burden interaction was proposed. The burden interaction is followed by melt dripping and melting of the burden. The melting onset temperatures were estimated from the isothermal section modeling of the phase diagrams and liquid mass fraction calculations obtained using FactSage software and databases. The phase diagrams supported the experimental observations such as non-melting of olivine particles in the olivine fluxed pellets and slag homogenization at 1300°C in the basic pellets. Addition of magnesia in lieu of lime was found to provide beneficial impact, in particular on the rate of liquid evolution at high temperature. Effect of alkali, even in small amounts, was deleterious for high temperature properties, especially in terms of early melt onset and lowering of the viscosity of the slag formed.

Kaushik, Pallav

296

Atmospheric structure from Phoenix atmospheric entry data  

NASA Astrophysics Data System (ADS)

The atmospheric structure at the time of landing of NASA's Phoenix probe has been derived from measurements of the aerodynamic drag of the spacecraft during atmospheric entry and descent. The result provides the first atmospheric structure in Mars' polar environment obtained from in situ measurements. Phoenix was equipped with an inertial measurement unit (IMU) that used accelerometers for linear acceleration measurement in three Cartesian axes and ring-laser gyroscopes to measure the three- dimensional orientation of the probe (Taylor et al., 2008). The temperature structure of the atmosphere along the flight path was calculated via a four-step process: (i) integrating forward the IMU data to obtain the time history of the spacecraft velocity vector relative to the atmosphere as a function of altitude; (ii) calculating atmospheric density from drag, with iteration for aerodynamic coefficient dependence on density; (iii) integrating the hydrostatic equation to derive the vertical pressure; and (iv) calculating atmospheric temperature from the equation of state. Initial profile reconstruction shows reasonable agreement with predictions in the middle atmosphere for the given season and time of day (landing occurred at 16h 33min 37sec in local solar time expressed as a 24-hour clock). However, the derived lower atmospheric structure below ~0.1 mbar is generally warmer than predicted. A possible explanation could be a shallower vertical distribution of dust that usually assumed. References: P. A. Taylor, D. C. Catling, M. Daly, C. S. Dickinson, H. O. Gunnlaugsson, A-M. Harri, C. F. Lange, Temperature, pressure and wind instrumentation on the Phoenix meteorological package, J. Geophys. Res., 113, EA0A10, doi:10.1029/2007JE003015, 2008.

Catling, D. C.

2008-12-01

297

Problem of the Neurodynamic Code of Mental Phenomena.  

National Technical Information Service (NTIS)

The report contains a discussion of the problem of the neurodynamic code of mental phenomena which deals with the philosophical, psychological, cybernetic and ethical aspects of investigation of the brain and its mental functions.

D. I. Dubrovskii

1975-01-01

298

Monitoring of Large Phenomena in Developing Countries Through Satellite Imagery.  

National Technical Information Service (NTIS)

Inter-annual comparisons between satellite images showing the effects of slowly evolving phenomena such as forest degradation or desert spreading, and intra-annual comparisons between images showing the flooding conditions over large areas are discussed. ...

L. Guyot

1986-01-01

299

Recent Advances in Cooperative Phenomena and Matter Field Interactions.  

National Technical Information Service (NTIS)

Partial Contents: Interaction of a Molecular Gas with the Electromagnetic Field; An Effective Hamiltonian for the Treatment of N Identical Two-Level Atoms Interacting with the Electromagnetic Field; and Light-Atom Interaction in Cooperative Phenomena in Q...

D. W. Howgate C. M. Bowden C. A. Coulter C. C. Sung

1980-01-01

300

Investigations into Biofouling Phenomena in Fine Pore Aeration Devices.  

National Technical Information Service (NTIS)

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 fro...

W. Jansen J. W. Costerton H. Melcer

1994-01-01

301

Analysis of Penetration and Ricochet Phenomena in Oblique Hypervelocity Impact.  

National Technical Information Service (NTIS)

An experimental investigation of phenomena associated with the oblique hypervelocity impact of spherical projectiles on multisheet aluminum structures is described. A model that can be employed in the design of meteoroid and space debris protection system...

W. P. Schonberg R. A. Taylor J. R. Horn

1988-01-01

302

Symposium Q: Magnetoelectronics - Novel Magnetic Phenomena in Nanostructures.  

National Technical Information Service (NTIS)

The area of anisotropic magnetotransport in magnetic superlattices remains controversial and intensely investigated by theorists and experimentalists, as demonstrated in Symposium Q on Magnetoelectronics-Novel Magnetic Phenomena in Nanostructures. The mai...

I. K. Schuller G. Guntherodt A. D. Kent T. Shinjo

2002-01-01

303

Uhthoff's phenomena in MS-clinical features and pathophysiology.  

PubMed

In the late 19(th) century, Wilhelm Uhthoff reported on a series of patients with acute optic neuritis who manifested similar recurrent, stereotyped visual symptoms that were of paroxysmal onset, short in duration, and reversible. These 'Uhthoff's phenomena', which are a feature of multiple sclerosis (MS) and other demyelinating diseases, can be triggered by factors including the perimenstrual period, exercise, infection, fever, exposure to high ambient temperatures, and psychological stress. Here, we characterize the clinical, pathophysiological and neurotherapeutic challenges associated with Uhthoff's phenomena, and discuss the differentiation of these events from other paroxysmal, acute or subacute changes in functional capabilities and neurological symptoms in MS. For instance, whereas MS exacerbations are contingent on immune dysregulation, Uhthoff's phenomena are predicated on ion channel modifications, in conjunction with thermoregulatory derangements that transiently alter the conduction properties of demyelinated axons. An understanding of these pathophysiological underpinnings of Uhthoff's phenomena is germane to their recognition and timely treatment. PMID:23732530

Frohman, Teresa C; Davis, Scott L; Beh, Shin; Greenberg, Benjamin M; Remington, Gina; Frohman, Elliot M

2013-06-04

304

Far-From-Equilibrium Phenomena at Local Sites of Reaction.  

National Technical Information Service (NTIS)

Both theoretical and experimental work have been reported on instabilities in purely dissipative bulk systems in which occur chemical reactions and transport processes such as diffusion. The authors investigate instabilities and related phenomena in syste...

K. Bimpong-Bota P. Ortoleva J. Ross

1974-01-01

305

Analysis of nuclear reactor instability phenomena. Progress report  

SciTech Connect

The phenomena known as density-wave instability often occurs in phase change systems, such as boiling water nuclear reactors (BWRS). Our current understanding of density-wave oscillations is in fairly good shape for linear phenomena (eg, the onset of instabilities) but is not very advanced for non-linear phenomena [Lahey and Podowski, 1989]. In particular, limit cycle and chaotic instability modes are not well understood in boiling systems such as current and advanced generation BWRs (eg, SBWR). In particular, the SBWR relies on natural circulation and is thus inherently prone to problems with density-wave instabilities. The purpose of this research is to develop a quantitative understanding of nonlinear nuclear-coupled density-wave instability phenomena in BWRS. This research builds on the work of Achard et al [1985] and Clausse et al [1991] who showed, respectively, that Hopf bifurcations and chaotic oscillations may occur in boiling systems.

Lahey, R.T. Jr.

1993-03-01

306

Fifth International Conference on Dielectric and Related Phenomena.  

National Technical Information Service (NTIS)

The Final Proceedings for Fifth International Conference on Dielectric and Related Phenomena, 24 September 1998 - 27 September 1998 This is an interdisciplinary conference. Topics include: relaxation theory, characterized of dielectric responses, molecula...

1998-01-01

307

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...

308

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...

309

Surface effects and Io volcano effects [satellite mutual phenomena  

Microsoft Academic Search

Very high astrometric accuracy in observation of mutual phenomena is possible only if photometric surface effects are taken into account in the reduction. On the other hand, such observations allow to get physical information about surface regolith.

P. Descamps

1996-01-01

310

Effect of distance from sea on atmospheric corrosion rate  

SciTech Connect

The influence of the distance from sea constitutes one of the most important aspects of atmospheric corrosion in coastal areas. Empirically, it is known that the effect of marine atmospheres extends principally some few hundred meters from the shoreline and decays rapidly further inland. As coastal corrosion rate depends on the concentration of chloride in the atmosphere, influence of wind and surf zone on the production of saline droplets and the decrease of the amount of these droplets from settling and impingement were discussed. The complexity of phenomena associated with marine atmospheric corrosion makes it difficult to devise a model that covers all scenarios. However, for the areas closest to the shoreline ({approximately} 400 m to 600 m), using published data, it was shown that the decrease of the corrosion rate with distance from the sea is represented fairly well by a simple exponential relationship.

Feliu, S.; Morcillo, M.; Chico, B. [CSIC, Madrid (Spain). Centro Nacional de Investigaciones Metalurgicas

1999-09-01

311

Statistical/Trend analysis of the marine atmospheric boundary layer model  

NASA Astrophysics Data System (ADS)

Transmission and reception of electromagnetic (EM) energy by communications, weapons, and active/passive sensor systems is known to be strongly influenced by an atmospheric phenomena known as ducting, caused by refractive layers in the atmosphere of marine environments. The Naval Postgraduate School (NPS) has developed a Marine Atmospheric Boundary Layer (MABL) model which can be used to predict, over a 24 hour period, the refractive profile of the lower atmosphere. This thesis examines the model from the statistical/trend analysis approach to examine whether the model can be used as a valid predictor of refractive/ducting conditions.

Bisking, R. D.

1984-09-01

312

Infrasound as an upper atmospheric probe: review and recent results  

NASA Astrophysics Data System (ADS)

Specification of upper atmospheric properties is hampered by the relatively small amount of direct observations in comparison to the lower atmosphere. Methods to measure the properties of the atmosphere above the stratopause is an active area of scientific research. In the past, a number of studies have focused on the use of infrasound as an upper atmospheric monitor, using naturally occurring infrasound from volcanoes and from microbaroms. It has been shown that infrasound propagation is sensitive to upper atmospheric dynamics, dominated by planetary waves, atmospheric tides, gravity waves and interactions of these phenomena. It has been found that upper atmospheric wind models are not always validated by infrasound data. Thus, infrasound measurements provide valuable information that can be used to validate and improve current understanding of winds in the mesosphere and lower thermosphere. Development of inverse procedures will allow one to use infrasound data to update upper atmospheric horizontal wind models. In this presentation, we will present a review of previous work and the application of an inverse procedure. The method, based on linearization of ray theory, is applied to infrasound signals from detonation activities at the Utah Test and Training Range (UTTR), measured on a dense infrasound network in the American West.

Assink, J. D.; Lalande, J.-M.; Talmadge, C.; Waxler, R.; Le Pichon, A.; Blanc, E.; Blanc-Benon, Ph.

2012-04-01

313

Search for new phenomena in the CDF top quark sample  

SciTech Connect

We present recent results from CDF in the search for new phenomena appearing in the top quark samples. These results use data from p{bar p} collisions at {radical}s = 1.96 TeV corresponding to an integrated luminosity ranging from 195 pb{sup -1} to 760 pb{sup -1}. No deviations are observed from the Standard Model expectations, so upper limits on the size of possible new phenomena are set.

Lannon, Kevin; /Ohio State U.

2006-10-01

314

Assessing psychologists' knowledge and attitudes toward near-death phenomena  

Microsoft Academic Search

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

Barbara A. Walker; Robert D. Russell

1989-01-01

315

Interfacial phenomena and microscale transport processes in evaporating ultrathin menisci  

Microsoft Academic Search

The study of interfacial phenomena in the three-phase contact line region, where a liquid-vapor interface intersects a solid surface, is of importance to many equilibrium and non-equilibrium processes. However, lack of experimental data on microscale transport processes controlled by interfacial phenomena has restricted progress. This thesis includes a high resolution image analyzing technique, based on reflectivity measurements, that accurately measures

Sashidhar S. Panchamgam

2006-01-01

316

Tilt rotor aeromechanics phenomena in low speed flight  

Microsoft Academic Search

This work investigates important aeromechanics phenomena affecting the V-22 tilt rotor in low speed sideward flight or while hovering in quartering or crosswind conditions. These phenomena, such as pitch-up with sideslip and increased power required in sideward flight, were identified during V-22 critical azimuth flight testing and impacted handling qualities in this flight regime. High fidelity, dynamic, unsteady, Navier-Stokes computational

Mark A. Potsdam; Mark J. Silva

2004-01-01

317

Are Transient Lunar Phenomena in Aristarchus Crater Surface Optical Effects?  

NASA Astrophysics Data System (ADS)

Aristarchus crater is the most prolific site for Transient Lunar Phenomena. Possible simple explanations for such phenomena could be sunglint from portions of parallel aligned near-specular surfaces, the opposition effect, or internal reflections from volcanic glass beads. An observational data base of TLPs, was used to investigate these theories, along with a control dataset of routine observations. However no definitive evidence in support of any of these ideas was been found.

Cook, A. C.; Grande, M.; Lane, J. A.

2011-10-01

318

Do there exist effects in the thermospheric plasma, arising from dynamic variations in the middle atmosphere  

SciTech Connect

An attempt is made to find effects in the lower thermosphere arising from dynamical phenomena in the underlying atmosphere. Wiese's (1951) analysis of midlatitude geomagnetic Sq-variation is repeated for the last 30 years and combined with other seasonal features and phenomena of the middle atmosphere region from 30 to 150 km, as derived from continuous meteorologic and ionospheric observations. The two basic states of this height region are traced from the stratosphere into the thermospheric Sq-region, and their characteristics are described.

Sonnemann, G.; Lauter, E.A.; Bremer, J.

1985-01-01

319

Space plasma physics: atmospheric emissions photometric imaging experiment.  

PubMed

The atmospheric emissions photometric imaging experiment was flown on Spacelab 1 to study faint natural and artificial atmospheric emission phenomena. The instrument imaged optical emission in the region 2000 to 7500 angstroms with a television system consisting of two optical channels, one wide-angle and one telephoto. A third optical channel imaged onto the photochathode of a microchannel plate photomultiplier tube that has 100 discrete anodes. A hand-held image intensifier camera with an objective grating permitted spectral analysis of the earth's airglow and the shuttle glow. Preliminary data show magnesium ion emission features in the lower ionosphere as well as the spececraft glow spectrum. PMID:17837937

Mende, S B; Swenson, G R; Clifton, K S

1984-07-13

320

Solar Irradiance of the Earth’s Atmosphere  

Microsoft Academic Search

\\u000a The sun is the primary driver of terrestrial atmospheric phenomena and energy source for the earth. It emits radiation over\\u000a a large energy band and ejects highly energetic plasma fluxes of charged particles into space. The sun is an active star that\\u000a (i) goes through a 12-year maximum–minimum emission cycle, (ii) has huge, non-periodic eruptions in solar flares and coronal

Sultana N. Nahar

321

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

NASA Astrophysics Data System (ADS)

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.

Samara, Marilia

2010-10-01

322

Dynamics of the solar photosphere. I. Two-dimensional spectroscopy of mesoscale phenomena.  

NASA Astrophysics Data System (ADS)

We address the "mesogranulation" phenomenon by analyzing a spectral time series, taken at disk center with a two-dimensional spectroscopy device and covering a period of 4 hours. This tunable device was composed by a Fabry-Perot interferometer mounted in tandem with an Universal Birefringent Filter (UBF). We calculate spatial power spectra, spatio-temporal k-? power, phase difference and coherence spectra at different low photospheric levels, in order to investigate the nature of the mesoscale phenomena. At the lowest levels, mesostructures appear as a part of an extended distribution of granular sizes without further distinction from granulation. Here, the plasma flows are driven by convection. On the other hand, a different mesoscale phenomenon emerges at levels as high as approximately 200-300km above ?_5000_=1, at medium spatial (k=~0.5...2Mm^-1^) and medium temporal (?=~0.5...1mHz) frequencies. This phenomenon is distinct from convection by its non-convective phase difference values ({PHI}_v-I_=~-30°, {PHI}_v-v_<0°) and by its different propagation character (almost horizontal propagation). By these properties, the mesoscale phenomena in the higher photosphere can be identified as internal gravity waves in the solar atmosphere.

Straus, T.; Bonaccini, D.

1997-08-01

323

Fair weather atmospheric electricity  

NASA Astrophysics Data System (ADS)

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.

Harrison, R. G.

2011-06-01

324

PANs in the atmosphere  

SciTech Connect

The types of peroxyacetyl nitrates (PANs) and peroxybenzyl nitrates (PBzNs) present or possibly present in the ambient atmosphere are discussed. Biological activities of the PANs and PBzNs are briefly considered. The concentration and composition of PANs in the atmosphere are discussed and calculations made of the production of RCO radicals from precursor alkanes, alkenes and aromatic hydrocarbons present in the atmosphere. Lifetimes of PANs are estimated, and the effects of transport on the composition of PANs has been evaluated.

Altshuller, A.P.

1993-09-01

325

Interactive atmosphere lab  

NSDL National Science Digital Library

The ozone layer makes up an important part of our atmosphere. This informational activity, part of an interactive laboratory series for grades 8-12, explores changes in ozone concentration with altitude. Students view a diagram that shows the layers of the atmosphere with a temperature scale running from the surface of the Earth to the outermost reaches of the atmosphere. After reading introductory material, students are presented with nine questions about the layers of the atmosphere and interactions with ozone. Copyright 2005 Eisenhower National Clearinghouse

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

2003-01-01

326

Comprehending emergent systems phenomena through direct-manipulation animation  

NASA Astrophysics Data System (ADS)

This study seeks to understand the type of interaction mode that best supports learning and comprehension of emergent systems phenomena. Given that the literature has established that students hold robust misconceptions of such phenomena, this study investigates the influence of using three types of interaction; speed-manipulation animation (SMN), post-manipulation animation (PMA) and direct-manipulation animation (DMA) for increasing comprehension and testing transfer of the phenomena, by looking at the effect of simultaneous interaction of haptic and visual channels on long term and working memories when seeking to comprehend emergent phenomena. The questions asked were: (1) Does the teaching of emergent phenomena, with the aid of a dynamic interactive modeling tool (i.e., SMA, PMA or DMA), improve students' mental model construction of systems, thus increasing comprehension of this scientific concept? And (2) does the teaching of emergent phenomena, with the aid of a dynamic interactive modeling tool, give the students the necessary complex cognitive skill which can then be applied to similar (near transfer) and/or novel, but different, (far transfer) scenarios? In an empirical study undergraduate and graduate students were asked to participate in one of three experimental conditions: SMA, PMA, or DMA. The results of the study found that it was the participants of the SMA treatment condition that had the most improvement in post-test scores. Students' understanding of the phenomena increased most when they used a dynamic model with few interactive elements (i.e., start, stop, and speed) that allowed for real time visualization of one's interaction on the phenomena. Furthermore, no indication was found that the learning of emergent phenomena, with the aid of a dynamic interactive modeling tool, gave the students the necessary complex cognitive skill which could then be applied to similar (near transfer) and/or novel, but different, (far transfer) scenarios. Finally, besides treatment condition, gender and age were also shown to be predictors of score differences; overall, males did better than females, and younger students did better than older students.

Aguirre, Priscilla Abel

327

Shape shifters: biobehavioral determinants and phenomena in symptom research.  

PubMed

Symptom assessment and management are critical to patient-centered care. Traditionally, the determinants of a symptom are viewed as separate from the phenomena associated with that symptom. By separating determinants and phenomena, however, the complexity and dynamism of the patient experience are ignored. Likewise, categorizing symptom determinants and phenomena as solely biological or behavioral minimizes their dimensionality and may hinder interdisciplinary dialogue. Here we propose that determinants and phenomena are not fixed but shift between each other depending on perspective. To illustrate this way of thinking the metaphor of the "shape shifter" from folklore is used. A shape shifter moves between states and may be seen differently by the same person at different times or by multiple individuals at one time. To guide discussion, we present 5 exemplars of increasing complexity, wherein a determinant becomes a phenomenon or vice versa, depending upon context. Suggestions for statistical testing of the model are included with each. We conclude by exploring how shifting between determinants and phenomena may affect symptom cluster assessment and management. PMID:22789451

Corwin, Elizabeth J; Meek, Paula; Cook, Paul F; Lowe, Nancy K; Sousa, Karen H

328

Millimeter-wave atmospheric turbulence measurements: Instrumentation, selected results, and system effects  

Microsoft Academic Search

Increasing interest in and greater usage of the millimeter-wave frequency bands has resulted in a need for better characterization\\u000a of atmospheric effects at these frequencies. While attenuation is recognized as the most significant effect, recent measurements\\u000a of fluctuations in intensity and phase caused by atmospheric turbulence have shown that these phenomena will also degrade\\u000a system performance at both millimeter-wave and

R. W. McMillan; R. A. Bohlander; W. J. Baldygo

1997-01-01

329

Evidence for a link between atmospheric thermonuclear detonations and nitric acid  

Microsoft Academic Search

Suitably located glacier cores, obtained from high-altitude, low-temperature sites, can reveal detailed information about atmospheric air chemistry at sub-annual resolution1. Such data may provide input to climate-change models, the study of acid precipitation patterns and many other phenomena. Here I present data from an ice core which show that during the era of intense atmospheric thermonuclear weapons testing (ATWT) a

G. Holdsworth

1986-01-01

330

Arc immobility and erosion phenomena in low pressure air  

Microsoft Academic Search

By using an experimental model of switching contacts in a demountable arc chamber, the initial immobility, edge immobility, and electrode erosion of switching arcs under a condition of low atmospheric pressure of 0.1 to 0.048 MPa in air (corresponding to the atmospheric pressure range of 0-6 km above sea level) were experimentally investigated. The results show that when the atmospheric

Cheng Li-Chun; Wan Bu-Yun

1990-01-01

331

Signal cancellation phenomena in adaptive antennas - Causes and cures  

NASA Astrophysics Data System (ADS)

Conventional adaptive beamformers utilizing some form of automatic minimization of mean square error exhibit signal cancellation phenomena when adapting rapidly. These effects result from adaptive interaction between signal and interference, when signal and interference are received simultaneously. Similar phenomena have been observed and analyzed in relatively simple adaptive noise cancelling systems. A study of these phenomena in the simpler systems is used to provide insight into similar behavior in adaptive antennas. A method for alleviating signal cancellation has been devised by Duvall, whereby the signal components are removed from the adaptive process, then reinserted to form the final system output. Widrow has devised a different solution to the problem: to move the receiving array spatially (or electronically) to modulate emanations received off the look direction, without distorting useful signals incident from the look direction. This approach is called 'spatial dither' and introduces the additional possibility of modulating 'smart' jammer signals, thereby limiting their effectiveness.

Widrow, B.; Gooch, R. P.; Newman, W. C.; Duvall, K. M.

1982-05-01

332

Pendulum Phenomena and the Assessment of Scientific Inquiry Capabilities  

NASA Astrophysics Data System (ADS)

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.

Zachos, Paul

2004-11-01

333

The Center for Natural Phenomena Engineering (CNPE), 1990--1991  

SciTech Connect

The Center for Natural Phenomena Engineering (CNPE) was established to provide a natural phenomena (NP) engineering oversight role within Martin Marietta Energy Systems, Inc. (MMES). In this oversight role CNPE`s goals are to provide coordination and direction of activities related to earthquake and other natural phenomena engineering, including development of hazard definition, development of design criteria, conducting new facility design, development and conducting of testing, performance of analysis and vulnerability studies, development of analysis methodology, and provision of support for preparation of safety analysis reports for the five MMES sites. In conducting these activities it is CNPE`s goal to implement the elements of Total Quality Management (TQM) in a cost-effective manner, providing its customers with a quality product. This report describes 1990--1991 activities.

Not Available

1992-07-01

334

Modified Phenomena Identification and Ranking Table (PIRT) for Uncertainty Analysis  

SciTech Connect

This paper describes a methodology of characterizing important phenomena, which is also part of a broader research by the authors called 'Modified PIRT'. The methodology provides robust process of phenomena identification and ranking process for more precise quantification of uncertainty. It is a two-step process of identifying and ranking methodology based on thermal-hydraulics (TH) importance as well as uncertainty importance. Analytical Hierarchical Process (AHP) has been used for as a formal approach for TH identification and ranking. Formal uncertainty importance technique is used to estimate the degree of credibility of the TH model(s) used to represent the important phenomena. This part uses subjective justification by evaluating available information and data from experiments, and code predictions. The proposed methodology was demonstrated by developing a PIRT for large break loss of coolant accident LBLOCA for the LOFT integral facility with highest core power (test LB-1). (authors)

Gol-Mohamad, Mohammad P.; Modarres, Mohammad; Mosleh, Ali [University of Maryland, College Park, MD 20742 (United States)

2006-07-01

335

Atmosphere Composition Model  

NSDL National Science Digital Library

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.

Lambertson, Lori

2007-01-01

336

Stacking up the Atmosphere  

NSDL National Science Digital Library

In this hands-on activity, participants learn the characteristics of the five layers of the atmosphere and make illustrations to represent them. They roll the drawings and place them in clear plastic cylinders, and then stack the cylinders to make a model column of the atmosphere.

Youngman, Betsy; Pennycook, Jean; Huffman, Louise; Dahlman, Luann; Nebraska, Andrill- U.

337

Venus Upper Atmosphere Structure  

Microsoft Academic Search

From analysis of the orbiter atmospheric drag (OAD) data obtained from the orbital decay of the Pioneer Venus orbiter from December 9, 1978, to August 7, 1979, atmospheric densities have been determined and tabulated near 16øN latitude between 140 and 190 km for all times of day. Maximum daytime densities on Venus are approximately 8 x 10 -13 g cm

G. M. Keating; J. Y. Nicholson; L. R. Lake

1980-01-01

338

PANS IN THE ATMOSPHERE  

EPA Science Inventory

The types of PANs and PBzN's present or possibly present in the ambient atmosphere are discussed. iological activities of the PAN's and PBzN's are briefly considered. he concentration and composition of PANs in the atmosphere are discussed and calculations made of the production ...

339

Exploring Hot Neptune Atmospheres  

NASA Astrophysics Data System (ADS)

The first transiting 'hot Neptune'' GJ 436b inhabits an entirely new region of phase space for extrasolar planetary atmospheres. This relatively cool, low-mass object should be the first transiting extrasolar planet to sport a methane-rich atmosphere. Like Uranus and Neptune it may also have an atmosphere highly enriched in heavy elements. Our experience with the complex atmospheres of the known hot-Jupiters has demonstrated that insights are best gained through the combination of Spitzer observations and atmospheric modeling . However, no models have investigated the atmospheres of Neptune-class exoplanets, which may well be super metal-enriched, and span a wider range in stellar insolation and atmospheric composition than we have previously encountered. GJ 436b the coldest transiting planet, is in entirely new irradiation and mass regimes and is also the target of a barrage of planned Spitzer observations. Here we propose a new generation of atmospheric modeling to understand Spitzer observations of this new planet and others like it.

Fortney, Jonathan; Marley, Mark; Saumon, Didier

2008-03-01

340

Micro- and Mesoscale Phenomena in Space Plasmas Conference  

NASA Astrophysics Data System (ADS)

A detailed assessment of many of the important mesoscale and microscale processes in geospace was the purpose of the Chapman Conference on “Micro- and Mesoscale Phenomena in Space Plasmas,” held at Kauai, Hawaii, from February 11 to 16. The practical goals of the conference were to facilitate the exchange of information on small- and medium-scale phenomena in space plasmas and to increase awareness of the needs of experimentalists and theorists, with a certain focus toward the ongoing Geospace Environment Modeling (GEM) and Space Physics Theory programs. The conference was organized by Maha Ashour-Abdalla (UCLA), Tom Chang (MIT), and Paul Dusenbery (U. Colorado).

Burch, J. L.

341

RELAP5-3D Code Validation for RBMK Phenomena  

SciTech Connect

The RELAP5-3D thermal-hydraulic code was assessed against Japanese Safety Experiment Loop (SEL) and Heat Transfer Loop (HTL) tests. These tests were chosen because the phenomena present are applicable to analyses of Russian RBMK reactor designs. The assessment cases included parallel channel flow fluctuation tests at reduced and normal water levels, a channel inlet pipe rupture test, and a high power, density wave oscillation test. The results showed that RELAP5-3D has the capability to adequately represent these RBMK-related phenomena.

Fisher, James Ebberly

1999-09-01

342

Fundamental investigation of duct/ESP phenomena. Final report  

SciTech Connect

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)

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

343

[Clinical analysis of paroxysmal motor phenomena in the neonate].  

PubMed

The newborn infant is prone to motor phenomena of various physiological mechanisms and pathological significance whereas they can share close clinical patterns. A detailed clinical analysis, that should be supported by a video EEG recording, is necessary. That may help to distinguish myoclonus, jitteriness or seizures. Some rare phenomenom such as hyperekplexia or myotonia have also to be known. The pregnancy and birth history, the clinical examination and the search for association of various motor phenomena give essential clues for the diagnosis. Misdiagnosing non epileptic phenomona as seizures has to be avoided as it leads to unnecessary anticonvulsivant therapy with potential harmful effects. PMID:21763975

Tich, S Nguyen The

2011-07-01

344

Modelling atmospheric flows with adaptive moving meshes  

NASA Astrophysics Data System (ADS)

An anelastic atmospheric flow solver has been developed that combines semi-implicit non-oscillatory forward-in-time numerics with a solution-adaptive mesh capability. A key feature of the solver is the unification of a mesh adaptation apparatus, based on moving mesh partial differential equations (PDEs), with the rigorous formulation of the governing anelastic PDEs in generalised time-dependent curvilinear coordinates. The solver development includes an enhancement of the flux-form multidimensional positive definite advection transport algorithm (MPDATA) — employed in the integration of the underlying anelastic PDEs — that ensures full compatibility with mass continuity under moving meshes. In addition, to satisfy the geometric conservation law (GCL) tensor identity under general moving meshes, a diagnostic approach is proposed based on the treatment of the GCL as an elliptic problem. The benefits of the solution-adaptive moving mesh technique for the simulation of multiscale atmospheric flows are demonstrated. The developed solver is verified for two idealised flow problems with distinct levels of complexity: passive scalar advection in a prescribed deformational flow, and the life cycle of a large-scale atmospheric baroclinic wave instability showing fine-scale phenomena of fronts and internal gravity waves.

Kühnlein, Christian; Smolarkiewicz, Piotr K.; Dörnbrack, Andreas

2012-04-01

345

Search for Periodic Trends in Saturn's Atmosphere  

NASA Astrophysics Data System (ADS)

The seasonal variability of Saturn's clouds and weather layer, currently displaying a variety of phenomena (convective storms, planetary waves, giant storms and lightning-induced events, etc.) is not fully understood. Additionally, variations of Saturn's radiance at 5.2 microns, a spectral region that is dominated by thermal emisison in an atmospheric window containing only weak gaseous absorption, contain a strong axisymmetric component as well as large discrete features at low and mid-latitutdes that are several degrees colder than the planetary average and uncorrelated with features at shorter wavelengths that are dominated by reflected sunlight. The characterization of several fundamental atmospheric properties and processes remains incomplete, namely: How do seasons affect (a) the global distribution of gaseous constituents and aerosols; and (b) temperatures and the stability against convection and large scale-atmospheric transport? What is the tropospheric cloud inventory? What is the relation between the fine-scale cloud structure identified at 5 microns and the distribution of condensates, such as ammonia? Do 5-micron clouds have counterparts at other altitude levels? What changes occur during the emergence of Great White Storms? Data acquired at the NASA/IRTF and NAOJ/Subaru from 1995

Yanamandra-Fisher, Padma

2012-07-01

346

The atmosphere below. (Videotape)  

SciTech Connect

In this educational `Liftoff to Learning` video series, astronauts from the STS-45 Space Shuttle Mission (Kathy Sullivan, Byron Lichtenberg, Brian Duffy, Mike Foale, David Leestma, Charlie Bolden, and Dirk Frimont) explain and discuss the Earths atmosphere, its needs, the changes occurring within it, the importance of ozone, and some of the reasons behind the ozone depletion in the Earths atmosphere. The questions of: (1) what is ozone; (2) what has happened to the ozone layer in the atmosphere; and (3) what exactly does ozone do in the atmosphere, are answered. Different chemicals and their reactions with ozone are discussed. Computer animation and graphics show how these chemical reactions affect the atmosphere and how the ozone hole looks and develops at the south pole during its winter season appearance.

NONE

1992-12-31

347

Analysis of Atmospheric Aerosols  

NASA Astrophysics Data System (ADS)

Aerosols represent an important component of the Earth's atmosphere. Because aerosols are composed of solid and liquid particles of varying chemical complexity, size, and phase, large challenges exist in understanding how they impact climate, health, and the chemistry of the atmosphere. Only through the integration of field, laboratory, and modeling analysis can we begin to unravel the roles atmospheric aerosols play in these global processes. In this article, we provide a brief review of the current state of the science in the analysis of atmospheric aerosols and some important challenges that need to be overcome before they can become fully integrated. It is clear that only when these areas are effectively bridged can we fully understand the impact that atmospheric aerosols have on our environment and the Earth's system at the level of scientific certainty necessary to design and implement sound environmental policies.

Prather, Kimberly A.; Hatch, Courtney D.; Grassian, Vicki H.

2008-07-01

348

Earth's Atmosphere Wind Dance  

NSDL National Science Digital Library

This lesson introduces the expanding and condensing properties of air masses and the unequal heating of Earth as the force behind the wind, it also displays the structure of the earth's atmosphere and the science concepts of layering, air density, and particles by using dance concepts such as level and shape. Students use previously learned movement skills to relay information about winds and the structure of the atmosphere. Hello Students! In class we have been learning about the atmosphere, to review some of what we've learned please follow the directions below! To read about the five layers that make up the earth's atmosphere click on this link: 5 Layers of the Atmosphere To learn about the properties of wind click on this link: Wind To learn ...

Magnuson, Miss

2009-12-07

349

Microbiology and atmospheric processes: an upcoming era of research on bio-meteorology  

NASA Astrophysics Data System (ADS)

For the past 200 years, the field of aerobiology has explored the abundance, diversity, survival and transport of micro-organisms in the atmosphere. Micro-organisms have been explored as passive and severely stressed riders of atmospheric transport systems. Recently, an interest in the active roles of these micro-organisms has emerged along with proposals that the atmosphere is a global biome for microbial metabolic activity and perhaps even multiplication. As part of a series of papers on the sources, distribution and roles in atmospheric processes of biological particles in the atmosphere, here we describe the pertinence of questions relating to the potential roles that air-borne micro-organisms might play in meteorological phenomena. For the upcoming era of research on the role of air-borne micro-organisms in meteorological phenomena, one important challenge is to go beyond descriptions of abundance of micro-organisms in the atmosphere toward an understanding of their dynamics in terms of both biological and physico-chemical properties and of the relevant transport processes at different scales. Another challenge is to develop this understanding under contexts pertinent to their potential role in processes related to atmospheric chemistry, the formation of clouds, precipitation and radiative forcing. This will require truly interdisciplinary approaches involving collaborators from the biological and physical sciences, from disciplines as disparate as agronomy, microbial genetics and atmosphere physics, for example.

Morris, C. E.; Sands, D. C.; Bardin, M.; Jaenicke, R.; Vogel, B.; Leyronas, C.; Ariya, P. A.; Psenner, R.

2008-01-01

350

Embedded phenomena: supporting science learning with classroom-sized distributed simulations  

Microsoft Academic Search

Embedded phenomena' is a learning technology framework in which simulated scientific phenomena are mapped onto the physical space of classrooms. Students monitor and control the local state of the simulation through distributed media positioned around the room, gathering and aggregating evidence to solve problems or answer questions related to those phenomena. Embedded phenomena are persistent, running continuously over weeks and

Tom Moher

2006-01-01

351

Theoretical analysis of deposition and melting process during throttling high pressure CO 2 into atmosphere  

Microsoft Academic Search

Previous study has discovered that periodic solid CO2 deposition and melting phenomena happen during releasing high pressure CO2 through a safety valve from CO2 refrigeration system into atmosphere, and that a longer duration of the deposition and a shorter duration of melting are advantageous for the system safety. In order to know the suitable parameters to get a longer duration

Dong-ping Huang; Guo-liang Ding; Hans Quack

2007-01-01

352

Nonsteady laboratory simulation of atmospheric vortices: Inertial oscillations and tornado skip  

Microsoft Academic Search

Vortices generated in a rotating tank of water exhibited persistent oscillations which had periods close to the inertial period. The persistency of these oscillations suggested that tornado skip phenomena and the life cycle of concentrated atmospheric vortices might be closely linked with inertial oscillations of a tall vortex. This mechanism would provide a means to concentrate angular momentum near ground

J. A. C. Kaiser

1976-01-01

353

The NetLander Atmospheric Instrument System (ATMIS): Technology and Performance assessment  

Microsoft Academic Search

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 Climate Orbiter have given a good understanding of the basic behavior of the Martian atmosphere. However, the more detailed characterisation of the Martian circulation patterns, boundary layer phenomena and climatological cycles

J. Polkko; A. Harri; A. Lehto; T. Siili; D. Crisp; S. Calcutt; S. Larsen

2001-01-01

354

Large eddy simulation of atmospheric boundary layer flows and application to pollen dispersal  

Microsoft Academic Search

This work presents a framework for simulating pollen dispersal by wind based on Large Eddy Simulation. Important phenomena such as pollen emission by plants and ground deposition are modeled through the boundary condition. An expression for the vertical equilibrium concentration profile of pollen particles, including the effect of the canopy on the eddy diffusivity as well as corrections for atmospheric

Marcelo Chamecki

2009-01-01

355

Water tank studies of atmospheric boundary layer structure and air pollution transport in upslope flow systems  

Microsoft Academic Search

Heated mountain slopes sometimes vent air pollutants out of the boundary layer over the slope top and at other times trap pollutants in closed circulations. Field, numerical, and water tank studies of fair weather atmospheric conditions over complex terrain have shown more complicated vertical distributions of temperature, moisture, and aerosols than over horizontal terrain. To study these phenomena, we analyze

C. Reuten; D. G. Steyn; S. E. Allen

2007-01-01

356

Measurements of solar flare enhancements to the single event upset environment in the upper atmosphere [avionics  

Microsoft Academic Search

The Cosmic Radiation Environment Monitor has flown regularly on a supersonic airliner over a period of 18 months in order to explore the extent of single-event phenomena in the upper atmosphere. Data presented are from flights occurring between November 1988 and May 1990. The detector system used is briefly described. Quiet-time data now have good statistical precision and are compared

C. S. Dyer; A. J. Sims; J. Farren; J. Stephen

1990-01-01

357

Atmospheric composition change: Ecosystems-Atmosphere interactions  

NASA Astrophysics Data System (ADS)

Ecosystems and the atmosphere: This review describes the state of understanding the processes involved in the exchange of trace gases and aerosols between the earth's surface and the atmosphere. The gases covered include NO, NO 2, HONO, HNO 3, NH 3, SO 2, DMS, Biogenic VOC, O 3, CH 4, N 2O and particles in the size range 1 nm-10 ?m including organic and inorganic chemical species. The main focus of the review is on the exchange between terrestrial ecosystems, both managed and natural and the atmosphere, although some new developments in ocean-atmosphere exchange are included. The material presented is biased towards the last decade, but includes earlier work, where more recent developments are limited or absent. New methodologies and instrumentation have enabled, if not driven technical advances in measurement. These developments have advanced the process understanding and upscaling of fluxes, especially for particles, VOC and NH 3. Examples of these applications include mass spectrometric methods, such as Aerosol Mass Spectrometry (AMS) adapted for field measurement of atmosphere-surface fluxes using micrometeorological methods for chemically resolved aerosols. Also briefly described are some advances in theory and techniques in micrometeorology. For some of the compounds there have been paradigm shifts in approach and application of both techniques and assessment. These include flux measurements over marine surfaces and urban areas using micrometeorological methods and the up-scaling of flux measurements using aircraft and satellite remote sensing. The application of a flux-based approach in assessment of O 3 effects on vegetation at regional scales is an important policy linked development secured through improved quantification of fluxes. The coupling of monitoring, modelling and intensive flux measurement at a continental scale within the NitroEurope network represents a quantum development in the application of research teams to address the underpinning science of reactive nitrogen in the cycling between ecosystems and the atmosphere in Europe. Some important developments of the science have been applied to assist in addressing policy questions, which have been the main driver of the research agenda, while other developments in understanding have not been applied to their wider field especially in chemistry-transport models through deficiencies in obtaining appropriate data to enable application or inertia within the modelling community. The paper identifies applications, gaps and research questions that have remained intractable at least since 2000 within the specialized sections of the paper, and where possible these have been focussed on research questions for the coming decade.

Fowler, D.; Pilegaard, K.; Sutton, M. A.; Ambus, P.; Raivonen, M.; Duyzer, J.; Simpson, D.; Fagerli, H.; Fuzzi, S.; Schjoerring, J. K.; Granier, C.; Neftel, A.; Isaksen, I. S. A.; Laj, P.; Maione, M.; Monks, P. S.; Burkhardt, J.; Daemmgen, U.; Neirynck, J.; Personne, E.; Wichink-Kruit, R.; Butterbach-Bahl, K.; Flechard, C.; Tuovinen, J. P.; Coyle, M.; Gerosa, G.; Loubet, B.; Altimir, N.; Gruenhage, L.; Ammann, C.; Cieslik, S.; Paoletti, E.; Mikkelsen, T. N.; Ro-Poulsen, H.; Cellier, P.; Cape, J. N.; Horváth, L.; Loreto, F.; Niinemets, Ü.; Palmer, P. I.; Rinne, J.; Misztal, P.; Nemitz, E.; Nilsson, D.; Pryor, S.; Gallagher, M. W.; Vesala, T.; Skiba, U.; Brüggemann, N.; Zechmeister-Boltenstern, S.; Williams, J.; O'Dowd, C.; Facchini, M. C.; de Leeuw, G.; Flossman, A.; Chaumerliac, N.; Erisman, J. W.

358

Numerical simulations of magnetic reconnection in the lower solar atmosphere  

NASA Astrophysics Data System (ADS)

Observations indicate that Ellerman bombs (EBs) and chromospheric microflares both occur in the lower solar atmosphere, and share many common features, such as temperature enhancements, accompanying jet-like mass motions, short lifetime, and so on. These strongly suggest that EBs and chromospheric microflares could both probably be induced by magnetic reconnection in the lower solar atmosphere. With gravity, ionization and radiation considered, we perform two-dimensional numerical simulations of magnetic reconnection in the lower solar atmosphere. The influence of different parameters, such as intensity of the magnetic field and anomalous resistivity, on the results are investigated. Our result demonstrates that the temperature increases are mainly due to the joule dissipation caused by magnetic reconnection. The spectral profiles of EBs and chromospheric microflares are calculated with the non-LTE radiative transfer theory and compared with observations. It is found that the typical features of the two phenomena can be qualitatively reproduced.

Xu, Xiao-Yan; Fang, Cheng; Ding, Ming-De; Gao, Dan-Hui

2011-02-01

359

The Composition Of Titan's Atmosphere As Seen By Herschel / Pacs  

NASA Astrophysics Data System (ADS)

Within the framework of the Herschel guaranteed time key project called ``Water and related chemistry in the Solar System''*, new insights into Titan's atmosphere are being facilitated by data from all three Herschel instruments (Heterodyne Instrument for the Far Infrared (HIFI), Photodetector Array Camera and Spectrometer (PACS), and Spectral and Photometric Imaging REceiver (SPIRE)). We present the first spectrum of Titan recorded by PACS during June 2010 (covering the 51 - 220 microns), with a resolving power from 940 to 5500 depending of the wavelength. The spectrum shows many lines due to H2O, HCN, CH4, and CO, we present the initial data analysis by means of a line-by-line radiative transfer code to infer abundances of the key constituents in Titan's atmosphere. Furthermore, this study attempts to contribute to a more thorough understanding of the physical phenomena in Titan's atmosphere. *also known as ``Herschel Solar System Observations'' (HssO) project

Rengel, Miriam; Hartogh, P.; Sagawa, H.; Lellouch, E.; Feuchgruber, H.; Jarchow, C.; Moreno, R.; Courtin, R.; HssO Team

2010-10-01

360

Thermocapillary and arc phenomena in stainless steel welding  

Microsoft Academic Search

This investigation characterized the effects of power level and Gaussian heat source size on thermocapillary-induced weld shape and estimated the relative influence of various possible arc phenomena in determining weld shape. Welds made with the CTAW process were compared with similar ones made with a conduction-mode EBW process and the differences were related to arc effects. Evidence of thermocapillary flow

S. W. Pierce; D. L. Olson; P. Burgardt

1999-01-01

361

Investigations of transient phenomena in MHD experimental facilities  

Microsoft Academic Search

Wideband data from experiments with combustion driven MHD power generation is presented. These data were achieved from past MHD research conducted by UTSI on several MHD test trains of variable size and interaction. Measurements of transient and dynamic phenomena related to combustion, plasmadynamics and MHD generator electrical output are discussed. The signal characteristics of these data are qualified and the

B. C. Winkleman; J. T. Lineberry

1991-01-01

362

Schizoid phenomena, psychobiology, and psychiatric paradigms: A proposed integrative model  

Microsoft Academic Search

The history and theoretical basis of schizoid phenomena, as described by the British Object-Relations theorists, are explored as a necessary philosophic paradigm to augment the biomedical model currently dominant in Western psychiatry. A “modular” model of the mind that includes the notion of multiple selves, is presented. A shift in paradigms from the nineteenth century, mechanistic concept of ego, to

Stephen DeBerry

1989-01-01

363

Reversion Phenomena in Cu-Zr-Cr Alloys.  

National Technical Information Service (NTIS)

Reversion phenomena in aged Cu-0.12% Zr-0.28% Cr alloy were investigated by means of resistivity measurement and transmission electron microscopy and compared with those of Cu-0.30% Zr and Cu-0.26% Cr alloys. Specimens in the form of a 0.5 mm sheet were s...

H. Suzuki H. Kitano M. Kanno

1985-01-01

364

Free energy calculations: Applications to chemical and biochemical phenomena  

SciTech Connect

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.

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

1993-11-01

365

Socio-optics: optical knowledge applied in modeling social phenomena  

NASA Astrophysics Data System (ADS)

The term "Socio-optics" (as a natural part of Socio-physics), is rather not found in literature or at Congresses. In Optics books, there are not made references to optical models applied to explain social phenomena, in spite of Optics relying on the duality particle-wave which seems convenient to model relationships among society and its members. The authors, who have developed a few models applied to explain social phenomena based on knowledge in Optics, along with a few other models applying, in Social Sciences, knowledge from other branches of Physics, give their own examples of such optical models, f. e., of relationships among social groups and their sub-groups, by using kowledge from partially coherent optical phenomena or to explain by tunnel effect, the apparently impossible penetration of social barriers by individuals. They consider that the term "Socio-optics" may come to life. There is mentioned the authors' expertise in stimulating Socio-optics approach by systematically asking students taken courses in Optics to find applications of the newly got Wave and Photon Optics knowledge, to model social and even everyday life phenomena, eventually engaging in such activities other possibly interested colleagues.

Chisleag, Radu; Chisleag Losada, Ioana-Roxana

2011-05-01

366

Do Particle Ideas Help or Hinder Pupils' Understanding of Phenomena?  

ERIC Educational Resources Information Center

|This paper addresses the question of whether particle ideas help or hinder young pupils' understanding of changes of state and dissolving. Two matched groups in a primary school in Greece (ages 10/11, n = 20 and n = 19) were respectively taught one of two parallel lesson schemes. Covering the same phenomena, one scheme incorporated particle…

Papageorgiou, George; Johnson, Philip

2005-01-01

367

High energy phenomena associated with gamma ray burst sources  

Microsoft Academic Search

Gamma-ray burst (GRB) spectrum is known to extend upto GeV energies, indicating the occurrence of transient high energy phenomena near GRB sources. Here we present evidence of statistical association between the locations of ultra high energy cosmic rays and GRBs. We examine our earlier finding that bright GRBs are associated with high energy cosmic rays (Energy > 3 × 1019

A. R. Rao; M. N. Vahia

1998-01-01

368

Beyond a Dichotomic Approach, the Case of Colour Phenomena  

ERIC Educational Resources Information Center

|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…

Viennot, L.; de Hosson, C.

2012-01-01

369

Severe convective storms and associated phenomena in Hungary  

Microsoft Academic Search

Convective activity dominates the weather of Hungary in the summer. Especially during the first part of the summer, the frequency of severe thunderstorms grows and associated phenomena such as wind storms, hail, sometimes even tornadoes cause serious damage. In this paper, an overview of the severe thunderstorm situation in the Carpathian Basin is presented with a focus on the most

Ákos Horváth; István Geresdi

2001-01-01

370

EZ lidar dust transit phenomena observations in Seoul, Korea  

Microsoft Academic Search

Duststorms and sandstorms regularly devastate Northeast Asia and cause considerable damage to transportation system and public health; further, these events are conceived to be one of the very important indices for estimating the global warming and desertification. Previously, yellow sand events were considered natural phenomena that originate in deserts and arid areas. However, the greater scale and frequency of these

S. Lolli; L. Sauvage; S. Loaec

2009-01-01

371

Vapor explosion phenomena with respect to nuclear reactor safety assessment  

Microsoft Academic Search

Stringent licensing procedures for commercial nuclear reactor operation require an in-depth analysis of the phenomena associated with postulated reactor core overheating accidents. One aspect of nuclear reactor safety assessment is a prediction of the consequences of interaction between molten fuel and coolant, in which rapid heat transfer from the fuel may lead to explosive vaporization of the coolant. Some of

A. W. Cronenberg; R. Benz

1978-01-01

372

Development of Understanding of Selected Science Phenomena in Young Children.  

ERIC Educational Resources Information Center

|The major purpose of this study was to investigate developmental patterns of understandings of four types of selected phenomena possessed by economically and racially different boys and girls. A total of 64 boys and girls, 32 blacks and 32 whites, were selected from Head Start, kindergarten, nursery, and primary schooling environments and then…

Donaldson, Marcia Jackson

373

Natural phenomena risk assessment at Rocky Flats Plant  

SciTech Connect

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.

Foppe, T.L.

1985-01-01

374

A molecular-scale view on rotary lip sealing phenomena  

Microsoft Academic Search

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

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

1999-01-01

375

NSF Combined Research and Curriculum Development on Multiphase Transport Phenomena  

Microsoft Academic Search

Summary This curriculum development project on multiphase transport phenomena draws on the research experiences from nine research laboratories at The University of Akron, Michigan State University, and the University of Tulsa. The objective of the project is to develop a new curriculum for teaching undergraduate and graduate students multiphase computational fluid dynamics for advanced design. The impact of multiphase flow

M. J. Amey; A. Bénard; G. G. Chase; E. A. Evans; K. Jayaraman; R. S. Mohan; S. M. Parks; C. A. Petty; O. Shoham; S. A. Shirazi; K. D. Wisecarver; M. Zhuang

2002-01-01

376

Nuclear phenomena in low-energy nuclear reaction research.  

PubMed

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

Krivit, Steven B

2013-08-15

377

Recursively speaking: analyzing students' discourse of recursive phenomena  

Microsoft Academic Search

Recursion is a powerful concept, appearing in almost every introductory course in computer-science (CS). CS educators and educational researchers often refer to difficulties in learning recursion, and suggest methods for teaching recursion. However, the research literature barely addresses the unique ways in which students relate to this interdisciplinary concept and the particular learners' language concerning recursive phenomena. The gap is

Dalit Levy; Tami Lapidot

2000-01-01

378

Technical aspects of interfacial phenomena in solid insulating systems  

Microsoft Academic Search

HV insulation systems are often composed of different insulating materials. In the contact areas between these materials (interfaces) interfacing polarization may occur, resulting in an increase of both permittivity and loss tangent and, consequently, of dielectric losses. By the interaction of humidity such interfacial phenomena may be enhanced. Other important characteristics of insulating systems such as the treeing strength and

H. C. Karner; M. Ieda

1991-01-01

379

Do Particle Ideas Help or Hinder Pupils' Understanding of Phenomena?  

Microsoft Academic Search

This paper addresses the question of whether particle ideas help or hinder young pupils' understanding of changes of state and dissolving. Two matched groups in a primary school in Greece (ages 10\\/11, n = 20 and n = 19) were respectively taught one of two parallel lesson schemes. Covering the same phenomena, one scheme incorporated particle ideas, and the other

George Papageorgiou; Philip Johnson

2005-01-01

380

A mechanistic model for the analysis of flashing phenomena  

Microsoft Academic Search

A mechanistic model is developed to analyze the swelling phenomena caused by flashing in a tank. Up to now, in the case of flashing in a tank, there is no reliable mechanistic model available to predict the swelling level and the void fraction when the flashing occurs. In this paper, a mechanistic model is developed to predict the swelling level,

Takanobu Watanabe; Goung Jin Lee; Takashi Iseki; Mamoru Ishii

1996-01-01

381

The Simulation Of Residual Tidal Phenomena In The White Sea  

NASA Astrophysics Data System (ADS)

Residual tidal phenomena (residual tidal circulation and residual tidal level) in the White Sea play a significant role in energy contribution to the formation of the hydrological regime. Non-linear residual tidal currents and sea level due to energy exchanges from the basic harmonics to the high frequency part of the spectrum have been poorly investigated in the White Sea until now. But residual tidal phenomena play an important role in the general circulation, which affects the temperature distribution and the drift of ice, plankton, pollution and other conservative tracers. We carried out numerical experiments with a non-linear hydrodynamic model to estimate the contributions of (shallow, friction and convective) nonlinearities to the residual tidal phenomena of White Sea's, using a `consecutive realisation' technique. The model grid's spatio-temporal resolution is more detailed than before: the Earth's geoid is approximated by the Krasovskiy rotation ellipsoid. A residual tidal level is observed in the low frequency part of spectrum of model results. In the linear approximation, the spectral density has a dominant peak at the frequencies of the basic harmonics in all parts of the sea, and the residual level was absent; overtones were not expressed. The experiments revealed that the residual circulation was defined by the convective non-linearity. The Earth's rotation does not change the current structure: only the circulation intensity decreases. These results will enhance the knowledge of tidal phenomena in the White Sea, and can be used for navigation, ecology and fisheries research.

May, R. I.

2004-12-01

382

Investigations of Basic Ablation Phenomena During Laser Thrombolysis  

Microsoft Academic Search

This paper presents studies of microsecond ablation phenomena that take place during during laser thrombolysis. The main goals were to optimize laser parameters for e-cient ablation, and to investigate the ablation mechanism. Gelatin containing an absorbing dye was used as the clot model. A parametric study was performed to identify the optimal wavelength, spot size, pulse energies, and repetition rate

Ujwal S. Sathyam; Alan Shearin; Scott A. Prahl

383

Correlation of Infrasonic Microbarometric Disturbances and Long Period Seismic Phenomena.  

National Technical Information Service (NTIS)

Detailed analyses of the correlation of infrasonic microbarometric disturbances and long-period seismic phenomena as recorded at the high-gain, wide-band, long-period seismic observatory at Sugar Island, Michigan, show very low coherency in the range of p...

M. J. S. Johnston P. W. Pomeroy

1971-01-01

384

Developing Critical Thinking through the Study of Paranormal Phenomena.  

ERIC Educational Resources Information Center

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…

Wesp, Richard; Montgomery, Kathleen

1998-01-01

385

Surface Phenomena of Molecular Clusters by Molecular Dynamics Method  

Microsoft Academic Search

Liquid droplets of water and argon surrounded by their vapor have been simulated by the molecular dynamics method. To explore the surface phenomena of clusters, each molecule is classified into 'liquid', 'surface', or 'vapor' with respect to the number of neighbor molecules. The contribution of a 'surface' molecule of the water cluster to the far infrared spectrum is almost the

Shigeo MARUYAMA; Sohei MATSUMOTO; Akihiro OGITA

1994-01-01

386

Integrating Some Mind and Brain Views of Transference: the Phenomena  

Microsoft Academic Search

Because understanding the underpinnings of transferential learning allows the analyst to more effectively exploit transference in the clinical situation, as well as to advance psychoanalytic theory, the functions and mechanisms of transference phenomena in learning are subjected to an interdisciplinary analysis. Through transference the brain creates hierarchical databases that make emotional sense of the world, especially the world of human

Fred M. Levin

1997-01-01

387

Boundary layer phenomena in combustion-driven MHD power generators  

Microsoft Academic Search

An analytic and experimental study of boundary layer phenomena in combustion-driven MHD power generators has been conducted. Measurements of heat transfer rates and velocity, temperature, and electron number density profiles were compared with numerical calculations. The analysis is based on the two-dimensional boundary layer equations. The velocity, temperature, and electron number density profiles were measured at the downstream end of

J. W. Daily

1975-01-01

388

Differences in physical phenomena governing laser machining of structural ceramics  

Microsoft Academic Search

Several structural ceramics such as alumina, silicon nitride, silicon carbide and magnesia were machined using a pulsed Nd:YAG laser. Laser processing conditions and temperature dependent thermo-physical properties govern the physical phenomena that machine these ceramics. Melting, dissociation and evaporation are some of the vital mechanisms associated with material removal. Discrimination and incorporation of these physical processes into a hydrodynamic machining

Anoop N. Samant; Narendra B. Dahotre

2009-01-01

389

Velocity shear induced phenomena in solar and astrophysical flows  

Microsoft Academic Search

Velocity shear induced phenomena in solar and astrophysical flows This thesis has concentrated on a non-modal analysis of flows with velocity inhomogeneities. Various astrophysical applications have been considered. In Chapter 2 we have studied a simple shear flow in order to demonstrate the non-modal method as well as basic properties of flows with inhomogeneous velocity fields. We illustrated the mathematical

A. G. Tevzadze

2006-01-01

390

A Content-Processing View of Hesitation Phenomena.  

ERIC Educational Resources Information Center

|Shows that hesitation phenomena are intricately connected with propspective and retrospective speech production tasks and mark critical points in processing. Two major hesitation categories exist: stalls and repairs. Stalls head off errors and represent error-free output; repairs take care of errors already committed. English and German examples…

Hieke, Adolf E.

1981-01-01

391

On the Cosmological Aspects of Observed High Energy Cosmic Phenomena  

Microsoft Academic Search

Super-high energy corpuscular and gamma rays as well as cosmic high--power density sources are hard to explain in a galaxy model framework. Attempts to include some of those phenomena in the Standard Cosmological Model also encounter serious difficulties. In the present paper an alternative cosmological concept is discussed. There are several features in it. First of all, the whole Universe

Anatoli Vankov

1999-01-01

392

Free energy calculations: Applications to chemical and biochemical phenomena  

Microsoft Academic Search

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.

Peter. Kollman

1993-01-01

393

Single heartbeat cardiac tagging for the evaluation of transient phenomena  

Microsoft Academic Search

Many cardiac abnormalities are of a transient nature, creating a beat-to-beat variation in myocardial function. This work pre- sents the cardiac imaging technique for the measurement of regional function during transient cardiac phenomena. All infor- mation necessary for the reconstruction of a cine loop is ac- quired within a single heartbeat, avoiding the temporal blurring introduced by segmented imaging due

Daniel A. Herzka; J. Andrew Derbyshire; Peter Kellman; Elliot R. McVeigh

2005-01-01

394

Effect of water dimer in insulating oil on conduction phenomena  

Microsoft Academic Search

An experimental study of the effect of water dimer in insulating oil on conduction phenomena is presented, and results are given. It is shown that saturated hydrocarbons do not include water dimer which combines with molecules of liquids by hydrogen bonds. The conductivity of saturated hydrocarbons is lower than that of alphatic hydrocarbons. The effect of water dimer on conductivity

S. Itahashi; T. Ueta; H. Sakurai; H. Mitsui; M. Sone

1993-01-01

395

Charging and discharging phenomena in simulated space environment  

Microsoft Academic Search

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

Masayuki HIKITA; Mengu CHO

2000-01-01

396

New Phenomena in NC Field Theory and Emergent Spacetime Geometry  

SciTech Connect

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.

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

2010-10-31

397

Student's Explanations of Chemical Phenomena: macro and micro differences  

Microsoft Academic Search

This study investigated patterns of students' science thinking across four different science phenomena, focusing on changes with age and science education. British secondary school students in three age groups were offered sentences appearing on a computer screen that gave different explanations for four common changes in materials: ice melting, sugar dissolving in water, a candle burning and an iron nail

Tim Brosnan; Yvonne Reynolds

2001-01-01

398

Quantication of spatiotemporal phenomena by means of cellular automata techniques  

Microsoft Academic Search

Quantication methods for spatiotemporal patterns are introduced, which are based on nearest- neighbor considerations inspired by cellular automata as well as by more complex spatiotemporal dynamics. In particular, spatial and temporal structures, which can be found in aggregation and clustering phenomena, are quantied by introducing the concept of cellular automata (CA) mea- sures for homogeneity and for the amount of

R. Neb

399

Quantification of spatiotemporal phenomena by means of cellular automata techniques  

Microsoft Academic Search

Quantification methods for spatiotemporal patterns are introduced, which are based on nearest-neighbor considerations inspired by cellular automata as well as by more complex spatiotemporal dynamics. In particular, spatial and temporal structures, which can be found in aggregation and clustering phenomena, are quantified by introducing the concept of cellular automata (CA) measures for homogeneity and for the amount of fluctuations contributing

M.-Th. Hütt; R. Neff

2001-01-01

400

Nuclear phenomena in low-energy nuclear reaction research  

NASA Astrophysics Data System (ADS)

This is a comment on Storms (Naturwissenschaften 97:861-881, 2010) Status of Cold Fusion, Naturwissenschaften, 97:861-881. This comment provides the following corrections: 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.

Krivit, Steven B.

2013-09-01

401

VARIATION IN PUBERTY PHENOMENA IN INBRED GILTS x  

Microsoft Academic Search

LARGE proportion of the pigs produced each year is farrowed by gilts. In spite of this, very little information is available on puberty phenomena in swine. The factors influencing age at puberty probably have been studied more extensively in the rat than in any other mammal. Hereditary differences in age at vaginal opening in different strains of rats have been

A. C. WARNICK; E. L. WIcx; L. E. CASIDA; A. B. CHAPMAN

2010-01-01

402

Signature analysis of flashover voltage phenomena on contaminated insulator surfaces  

Microsoft Academic Search

This paper discusses some of the physical process involved in the flashover of non-ceramic and ceramic contaminated insulator surfaces. The various discharges and flashover voltage (FOV) phenomena on insulator surfaces (nonceramic vs. ceramic) were investigated by means of slow and fast oscillographic recording of the discharge current. Discharge current signatures were analyzed by means of fast Fourier transform (FFT). It

Mirresh Shah

1996-01-01

403

ESD Phenomena and Protection Issues in CMOS Output Buffers  

Microsoft Academic Search

In VLSI devices with 1 ¿m CMOS technologies the use of silicided diffusions has been found to have a negative impact on the ESD protection levels of both inputs and outputs. In this paper the ESD phenomena for CMOS output buffers is presented to show that it can be improved for advanced processes. The primary findings here show that the

C. Duvvury; R. N. Rountree; Y. Fong; R. A. McPhee

1987-01-01

404

Flow electrification phenomena in paraffinic based transformer oil  

Microsoft Academic Search

The paper details, the effect of AC and DC energisation on the flow charging characteristics of paraffinic based transformer oil. The Couette device which simulates some of the practical configurations of a transformer, mainly the duct flow condition in the transformer was employed. Flow charging phenomena was quantified by evaluating variations in the charging current, voltage buildup and accumulated charge,

P. K. Poovamma; S. N. Moorching

1999-01-01

405

Interaction effects of wave propagation phenomena on aortic pressure  

Microsoft Academic Search

The effects on aortic pressure of various wave propagation phenomena, namely reflection coefficient, pulse wave velocity, and characteristic impedance, were studied in isolated rabbit hearts. Hearts were subjected to real-time computer-controlled artificial loading with a single tube model. This loading system allows for precise and independent control of all arterial model parameters and properties. Results indicate that reduced reflections and

D. S. Berger; K. A. Robinson; S. G. Shroff

1995-01-01

406

Recent LEP2 results on searches for new phenomena  

SciTech Connect

Recent results of searches for supersymmetric particles, Higgs bosons, and other new phenomena at LEP2 are summarized. These results are based on data and analyses from the four LEP experiments: ALEPH, DELPHI, L3, and OPAL. The data were collected during the summer and fall of 1996 with center-of-mass energies of 161 and 172 GeV.

Pan Yibin [Department of Physics, University of Wisconsin, 1150 University Ave., Madison, Wisconsin 53706 (United States)

1998-05-29

407

Change Blindness Phenomena for Virtual Reality Display Systems  

Microsoft Academic Search

In visual perception, change blindness describes the phenomenon that persons viewing a visual scene may apparently fail to detect significant changes in that scene. These phenomena have been observed in both computer-generated imagery and real- world scenes. Several studies have demonstrated that change blindness effects occur primarily during visual disruptions such as blinks or saccadic eye movements. However, until now

Frank Steinicke; Gerd Bruder; Klaus Hinrichs; Pete Willemsen

2011-01-01

408

Calibrating Atmospheric Transmission  

NASA Astrophysics Data System (ADS)

Earth's atmosphere is a wavelength-, directionally- and time-dependent turbid refractive element for every ground-based telescope. Changes in atmospheric transmission are the most significant systematic error limiting photometric measurement precision and accuracy. While considerable resources have been devoted to correcting the effects of the atmosphere on angular resolution, the effects on precision photometry have largely been ignored. To correct photometric measurements for the transmission of the atmosphere requires direct measurements of the wavelength-dependent transmission in the same direction and at the same time that the supported photometric telescope is acquiring its data. We describe the multi-wavelength lidar, the Facility Lidar for Astronomical Measurement of Extinction (FLAME) that observes the stable stratosphere, and a spectrophotometer (the Astronomical Extinction Spectrophotometer - AESoP) that creates and maintains NIST absolute standard stars, the combination of which enables fundamentally statistically limited photometric precision of both the stellar spectra and atmospheric transmission. The throughput of both FLAME and AESoP are calibrated to NIST radiometric standards. This inexpensive and replicable instrument suite provides the lidar-determined monochromatic transmission of Earth's atmosphere at visible and near-infrared wavelengths to 0.25% per airmass and the wavelength-dependent transparency to less than 1% uncertainty per nanometer per minute of time. These atmospheric data are merged to create a metadata stream that allows throughput corrections from data acquired at the time of the scientific observations to be applied to broadband and spectrophotometric scientific data. This new technique replaces the classical use of nightly mean atmospheric extinction coefficients, which invoke a stationary and plane-parallel atmosphere and ultimately limit ground-based all-sky photometry to 1% - 2% precision. This research is supported by NIST Award 60NANB9D9121 and NSF Grant AST-1009878.

Zimmer, Peter C.; McGraw, J. T.; Vorobiev, D. M.; Zirzow, D. C.; Karle, J. C.; Lykke, K. R.; Woodward, J. T.; Cramer, C. E.

2012-01-01

409

Photochemistry of Planetary Atmospheres  

NASA Astrophysics Data System (ADS)

The Space Age started half a century ago. Today, with the completion of a fairly detailed study of the planets of the Solar System, we have begun studying exoplanets (or extrasolar planets). The overriding question in is to ask whether an exoplanet is habitable and harbors life, and if so, what the biosignatures ought to be. This forces us to confront the fundamental question of what controls the composition of an atmosphere. The composition of a planetary atmosphere reflects a balance between thermodynamic equilibrium chemistry (as in the interior of giant planets) and photochemistry (as in the atmosphere of Mars). The terrestrial atmosphere has additional influence from life (biochemistry). The bulk of photochemistry in planetary atmospheres is driven by UV radiation. Photosynthesis may be considered an extension of photochemistry by inventing a molecule (chlorophyll) that can harvest visible light. Perhaps the most remarkable feature of photochemistry is catalytic chemistry, the ability of trace amounts of gases to profoundly affect the composition of the atmosphere. Notable examples include HOx (H, OH and HO2) chemistry on Mars and chlorine chemistry on Earth and Venus. Another remarkable feature of photochemistry is organic synthesis in the outer solar system. The best example is the atmosphere of Titan. Photolysis of methane results in the synthesis of more complex hydrocarbons. The hydrocarbon chemistry inevitably leads to the formation of high molecular weight products, giving rise to aerosols when the ambient atmosphere is cool enough for them to condense. These results are supported by the findings of the recent Cassini mission. Lastly, photochemistry leaves a distinctive isotopic signature that can be used to trace back the evolutionary history of the atmosphere. Examples include nitrogen isotopes on Mars and sulfur isotopes on Earth. Returning to the question of biosignatures on an exoplanet, our Solar System experience tells us to look for speciation that reveals the reaction pathways, disequilibrium forcing (what portion of the irradiance of the central star is harvested?) and isotopic signatures that are fingerprints of photochemistry and biochemistry.

Yung, Y. L.

2005-12-01

410

Atmospheric ionisation in Snowdonia  

NASA Astrophysics Data System (ADS)

Atmospheric ionisation from natural radioactivity and cosmic rays has been measured at several sites in Snowdonia from 2005-present. The motivation for this project was a combination of public engagement with science, and research into the effects of ionisation on climate. A four-component atmospheric radiometer instrument is co-located with the ionisation detectors and the data is remotely logged and displayed on the Web. Atmospheric ionisation from natural radioactivity varies with local geology, and the cosmic ray ionisation component is modulated by solar activity and altitude. Variations due to all these effects have been identified and are described.

Aplin, K. L.; Williams, J. H.

2011-06-01

411

Atmospheric refraction: a history  

NASA Astrophysics Data System (ADS)

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).

Lehn, Waldemar H.; van der Werf, Siebren

2005-09-01

412

MAH: Minimum Atmospheric Height  

NASA Astrophysics Data System (ADS)

MAH calculates the posterior distribution of the "minimum atmospheric height" (MAH) of an exoplanet by inputting the joint posterior distribution of the mass and radius. The code collapses the two dimensions of mass and radius into a one dimensional term that most directly speaks to whether the planet has an atmosphere or not. The joint mass-radius posteriors derived from a fit of some exoplanet data (likely using MCMC) can be used by MAH to evaluate the posterior distribution of R_MAH, from which the significance of a non-zero R_MAH (i.e. an atmosphere is present) is calculated.

Kipping, David M.; Spiegel, David S.; Sasselov, Dimitar D.

2013-07-01

413

Evolution of Atmospheres  

SciTech Connect

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.

Hanson, B.

1993-02-12

414

Seasonality of alcohol-related phenomena in Estonia  

NASA Astrophysics Data System (ADS)

We studied alcohol consumption and its consequences as a seasonal phenomenon in Estonia and analysed the social and environmental factors that may cause its seasonal rhythm. There are two important questions when researching the seasonality of human activities: (1) whether it is caused by natural or social factors, and (2) whether the impact of the factors is direct or indirect. Often the seasonality of social phenomena is caused by social factors, but the triggering mechanisms are related to environmental factors like temperature, precipitation, and radiation via the circannual calendar. The indicators of alcohol consumption in the current paper are grouped as: (1) pre-consumption phenomena, i.e. production, tax and excise, sales (beer, wine and vodka are analysed separately), and (2) post-consumption phenomena, i.e. alcohol-related crime and traffic accidents and the number of people detained in lockups and admitted to alcohol treatment clinics. In addition, seasonal variability in the amount of alcohol advertising has been studied, and a survey has been carried out among 87 students of Tartu University. The analysis shows that different phenomena related to alcohol have a clear seasonal rhythm in Estonia. The peak period of phenomena related to beer is in the summer, from June to August and the low point is during the first months of the year. Beer consumption correlates well with air temperature. The consumption of vodka increases sharply at the end of the year and in June; the production of vodka does not have a significant correlation with negative temperatures. The consumption of wine increases during summer and in December. The consequences of alcohol consumption, expressed as the rate of traffic accidents or the frequency of medical treatment, also show seasonal variability. Seasonal variability of alcohol consumption in Estonia is influenced by natural factors (temperature, humidity, etc.) and by social factors (celebrations, vacations, etc.). However, distinguishing between impacts of direct and indirect relationships is complicated, as they are interlinked.

Silm, Siiri; Ahas, Rein

2005-03-01

415

Is microbiolgy an alternative route to photochemistry in atmospheric chemistry?  

NASA Astrophysics Data System (ADS)

Until very recently scientists from atmospheric sciences focussed their studies on physical and chemical phenomena taking place in cloud water phase neglecting the presence of active microorganisms in this medium. For instance, considering atmospheric chemistry, solar light is considered as the predominant catalyser for chemical reactions occurring in the atmosphere. However recent studies show that living and active microorganisms, including bacteria, yeasts and fungi, are present in the atmospheric water phase and could play an active role in chemistry of clouds. Indeed living microorganisms are clearly biocatalysts which could transform organic compounds as an alternative route to photochemistry. The objective of our project is to bring answers to this new scientific question by a multidisciplinary approach involving atmospheric physicists, photochemists and microbiologists. Microorganisms have been isolated and identified in cloud water sampled at the puy de Dôme summit which is an atmospheric observatory and a European referenced site. Laboratory experiments were carried out to evaluate the potential of organic species (carboxylic acids) degradation by the photochemical or microbiological ways. The project was centred on few carboxylic acids among them succinic, acetic, formic and oxalic acids (the most important organic acids in cloud water sampled at Puy de Dôme). Degradation rates were measured during biodegradation alone (Pseudomonas syringae), photochemistry alone (hydrogen peroxide + light) and combing both processed using artificial reconstituted cloud water. Our first results show that the obtained degradation rates are in the range of order.

Vaitilingom, M.; Parazols, M.; Sancelme, M.; Deguillaume, L.; Mailhot, G.; Delort, A.-M.

2009-04-01

416

EDITORIAL: Spin-transfer-torque-induced phenomena Spin-transfer-torque-induced phenomena  

NASA Astrophysics Data System (ADS)

This cluster, consisting of five invited articles on spin-transfer torque, offers the very first review covering both magnetization reversal and domain-wall displacement induced by a spin-polarized current. Since the first theoretical proposal on spin-transfer torque—reported by Berger and Slonczewski independently—spin-transfer torque has been experimentally demonstrated in both vertical magnetoresistive nano-pillars and lateral ferromagnetic nano-wires. In the former structures, an electrical current flowing vertically in the nano-pillar exerts spin torque onto the thinner ferromagnetic layer and reverses its magnetization, i.e., current-induced magnetization switching. In the latter structures, an electrical current flowing laterally in the nano-wire exerts torque onto a domain wall and moves its position by rotating local magnetic moments within the wall, i.e., domain wall displacement. Even though both phenomena are induced by spin-transfer torque, each phenomenon has been investigated separately. In order to understand the physical meaning of spin torque in a broader context, this cluster overviews both cases from theoretical modellings to experimental demonstrations. The earlier articles in this cluster focus on current-induced magnetization switching. The magnetization dynamics during the reversal has been calculated by Kim et al using the conventional Landau--Lifshitz-Gilbert (LLG) equation, adding a spin-torque term. This model can explain the dynamics in both spin-valves and magnetic tunnel junctions in a nano-pillar form. This phenomenon has been experimentally measured in these junctions consisting of conventional ferromagnets. In the following experimental part, the nano-pillar junctions with perpendicularly magnetized FePt and half-metallic Heusler alloys are discussed from the viewpoint of efficient magnetization reversal due to a high degree of spin polarization of the current induced by the intrinsic nature of these alloys. Such switching can be further operated at high frequency resulting in an oscillator, as shown in the article by Sulka et al. These results provide fundamental elements for magnetic random access memories. The later articles discuss domain-wall displacement. Again this phenomenon is also described by Shibata et al based on the LLG equation with spin-torque terms. This analytical model can explain the details of the depinning mechanism and a critical current for the displacement. Experimental observation is presented in the subsequent article by Malinowski et al, showing the depinning processes for the cases of intrinsic and extrinsic pinning sites. Here, the detailed magnetic moment configurations within the wall hold the dominant control over the critical current. These results can be used for future 3-dimensional magnetic memories, such as racetrack memory proposed by IBM. We sincerely hope this cluster offers an up-to-date understanding of macroscopic behaviour induced by spin-transfer torque and contributes to further advancement in this exciting research field. We are grateful to all the authors for spending their precious time and knowledge submitting to this cluster. We would also like to thank Professor Kevin O'Grady for his kind offer of the opportunity to make this review accessible to a general audience.

Hirohata, Atsufumi

2011-09-01

417

Atmospheric Radiance Profile Codes.  

National Technical Information Service (NTIS)

This report presents and describes the computer codes developed to generate atmospheric radiance profiles for various molecules, species, and rotational bands. Researchers extracted radiance profiles from the standard NLTE program output files and transfe...

B. K. Yap

1986-01-01

418

Atmospheric Corrosion and Environment.  

National Technical Information Service (NTIS)

Results from an eight year atmospheric exposure of various materials at seven sites in China were summarized. The testing sites cover typical environments of temperate and subtropical, industrial and marine and rural, humid and dry. The effect of environm...

W. T. Hou C. F. Liang

1995-01-01

419

Our Changing Atmosphere.  

ERIC Educational Resources Information Center

Summarizes what is known about two major variables involved in certain types of chemical pollution that seem to be changing the structure of the Earth's atmosphere. Discusses the greenhouse effect and the ozone layer. (TW)

Clearing, 1988

1988-01-01

420

Remote Atmospheric Lasing.  

National Technical Information Service (NTIS)

This paper considers a remote atmospheric lasing configuration which utilizes a combination of an ultrashort pulse laser to form a plasma filament (seed electrons) by tunneling ionization and a heater beam which thermalizes the seed electrons. The thermal...

B. Hafizi D. Gordon J. Penano M. Scully P. Sprangle

2010-01-01

421

The changing atmosphere  

SciTech Connect

This book describes the causes of acid rain, ozone depletion, and global warming and the evidence for each one's recent acceleration. It provides practical and long-range suggestions for controlling these and other forms of atmospheric deterioration.

Firor, J. (National Center for Atmospheric Research (US))

1990-01-01

422

PANs in the Atmosphere.  

National Technical Information Service (NTIS)

The types of peroxyacetyl nitrates (PANs) and peroxybenzyl nitrates (PBzNs) present or possibly present in the ambient atmosphere are discussed. Biological activities of the PANs and PBzNs are briefly considered. The concentration and composition of PANs ...

A. P. Altshuller

1993-01-01

423

Our Changing Atmosphere.  

ERIC Educational Resources Information Center

|Summarizes what is known about two major variables involved in certain types of chemical pollution that seem to be changing the structure of the Earth's atmosphere. Discusses the greenhouse effect and the ozone layer. (TW)|

Clearing, 1988

1988-01-01

424

Students 'Weigh' Atmospheric Pollution.  

ERIC Educational Resources Information Center

|Describes a procedure developed by students that measures the mass concentration of particles in a polluted urban atmosphere. Uses a portable fan and filters of various materials. Compares students' data with official data. (DDR)|

Caporaloni, Marina

1998-01-01

425

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.

426

Atmospheric Corrections in Coastal Altimetry  

NASA Astrophysics Data System (ADS)

The range measurements from the altimeter are associated with a large number of geophysical corrections which needs special attention near coasts and the shallow water regions. The corrections due to ionosphere, dry and wet troposphere and that due to sea state are of primary importance in altimetry. Water vapor dominates the wet tropospheric corrections by several factors which is more complex with higher spatio-temporal variations and thus needs a careful attention near coasts. In addition to this rain is one of the major atmospheric phenomena which attenuate the backscatter altimeter measurements which in turn affect the altimeter derived wind and wave measurements. Thus during rain events utmost care should be taken while deriving the altimeter wind speeds and wave heights. The first objective of the present study involves the comparison of the water vapor corrections estimated from radiosonde measurements near the coastal regions with the model estimated corrections applied in the altimeter range measurements. Analysis has been performed for the Coastal Altimeter products provided by the PISTACH to observe these corrections. The second objective is to estimate the rain rate using altimeter backscatter measurements. The differential attenuation of KU band over C band due to rain has been utilized to identify the rain events and to estimate the amount of rain fall. JASON-2 altimeter data during two tropical cyclonic events over Bay of Bengal have been used for this purpose. An attempt is made to compare the estimated rain rate from altimeter measurements with the other available collocated satellite observations like KALPANA and TRMM-TMI. The results are encouraging and can be used to provide valid rain flags in the altimeter products in addition to the radiometer rain flags.

Antonita, Maria; Kumar, Raj

2012-07-01

427

In-situ observations of electric Field fluctuations and impulsive events during the Descent of the HUYGENS Probe in the atmosphere of Titan  

NASA Astrophysics Data System (ADS)

There is a long lasting debate about lightning on Titan. The existence of lightning or other discharge phenomena like corona discharge can help to understand the origin of life on Earth because it connects the complex organic chemistry on Titan with the prebiotic environment on Earth. The CASSINI/HUYGENS mission provided for the first time the opportunity to investigate in-situ electrical and acoustic phenomena in the atmosphere of Titan. During the descent of the HUYGENS probe the electric and acoustic sensors of the Permittivity, Wave and Altimetry experiment (PWA) as part of the Huygens Atmospheric Structure Instrument (HASI) observed fluctuations of the electric field up to 10 kHz and acoustic noise up to 6 kHz between 140 km and the surface. The observed electric field fluctuations and impulsive events have been compared with terrestrial atmospheric electricity phenomena and are most likely caused by electric discharges in the atmosphere of Titan.

Schwingenschuh, K.

428

"Storm Alley" on Saturn and "Roaring Forties" on Earth: two bright phenomena of the same origin  

NASA Astrophysics Data System (ADS)

"Storm Alley" on Saturn and "Roaring Forties' on Earth: two bright phenomena of the same origin. G. Kochemasov IGEM of the Russian Academy of Sciences, Moscow, Russia, kochem.36@mail.ru Persisting swirling storms around 35 parallel of the southern latitude in the Saturnian atmosphere and famous "Roaring Forties" of the terrestrial hydro- and atmosphere are two bright phenomena that should be explained by the same physical law. The saturnian "Storm Alley" (as it is called by the Cassini scientists) is a stable feature observed also by "Voyager". The Earth's "Roaring Forties" are well known to navigators from very remote times. The wave planetology [1-3 & others] explains this similarity by a fact that both atmospheres belong to rotating globular planets. This means that the tropic and extra-tropic belts of these bodies have differing angular momenta. Belonging to one body these belts, naturally, tend to equilibrate their angular momenta mainly by redistribution of masses and densities [4]. But a perfect equilibration is impossible as long as a rotating body (Saturn or Earth or any other) keeps its globular shape due to mighty gravity. So, a contradiction of tropics and extra-tropics will be forever and the zone mainly between 30 to 50 degrees in both hemispheres always will be a zone of friction, turbulence and strong winds. Some echoes of these events will be felt farther poleward up to 70 degrees. On Earth the Roaring Forties (40?-50?) have a continuation in Furious Fifties (50?-60?) and Shrieking (Screaming) Sixties (below 60?, close to Antarctica). Below are some examples of excited atmosphere of Saturn imaged by Cassini. PIA09734 - storms within 46? south; PIA09778 - monitoring the Maelstrom, 44? north; PIA09787 - northern storms, 59? north; PIA09796 - cloud details, 44? north; PIA10413 - storms of the high north, 70? north; PIA10411 - swirling storms, "Storm Alley", 35? south; PIA10457 - keep it rolling, "Storm Alley", 35? south; PIA10439 - dance of the clouds, 47? south; PIA10437 - dual vortices, 33? north. In the Earth's case the turbulence touches the atmosphere, oceans and lithosphere. Navigators for sailing use strong westerly winds in Roaring Forties. Europe is often hit by anomalous, sometimes disasters weather conditions (though winds in the northern hemisphere are somehow softened by landmasses). In the crust of Eurasia, North America and in the Southern ocean along latitudes 46?-48? there are two latitudinal geomorphologic planetary flexures marking transition of subsiding inward belts to uplifting outward (pole ward) belts [5]. These slow secular crust and lithosphere movements of opposite signs witness the tendency of rotating Earth to equilibrate angular momenta of its tropic and extra-tropic belts. Thus, both planets - the rocky sphere and the gaseous giant globe - obey the same fundamental law of nature and try to adjust uneven angular momenta of its tropic and extra-tropic belts marking transition between them by anomalous features. References: [1] Kochemasov G.G. Concerted wave supergranulation of the solar system bodies // 16th Russian-American microsymposium on planetology, Abstracts, Moscow, Vernadsky Inst. (GEOKHI), 1992, 36-37. [2] Kochemasov G.G. Tectonic dichotomy, sectoring and granulation of Earth and other celestial bodies // Proceedings of the International Symposium on New Concepts in Global Tectonics, "NCGT-98 TSUKUBA", Geological Survey of Japan, Tsukuba, Nov 20-23, 1998, p. 144-147. [3] Kochemasov G.G. Theorems of wave planetary tectonics // Geophys. Res. Abstr., 1999, V.1, ?3, 700. [4] Kochemasov G.G. Tectonics of rotating celestial globes // Vernadsky-Brown microsymposium 48, 20-22 Oct. 2008, Moscow, Abstr. m48_20. [5] Kotov F. S. A reflection of planetary flexures in limits of the continental lithosphere // Tectonics and geodynamics of the continental lithosphere. Proceedings of the XXXVI Tectonic conference. T. I, 4-6 Febr. 2003, Ed. Yu.V. Karyakin, Moscow, GEOS, 2003, 37

Kochemasov, G. G.

2009-04-01

429

Electric Field Observations during the Descent of the HUYGENS Probe: Evidence of Lightning in the Atmosphere of Titan  

NASA Astrophysics Data System (ADS)

The CASSINI HUYGENS mission provided for the first time the opportunity to investigate in-situ electrical and acoustic phenomena in the atmosphere of Titan During the descent of the HUYGENS probe the electric and acoustic sensors of the Permittivity Wave and Altimetry experiment PWA as part of the Huygens Atmospheric Structure Instrument HASI observed fluctuations of the electric field up to 10 kHz and acoustic noise up to 6 kHz The observed events below 140 km have been compared with the electric and acoustic parameters of terrestrial lightning phenomena and with the result calculated with a numerical model

Schwingenschuh, K.; Hofe, R.; Tokano, T.; Lopez-Moreno, J. J.; Grard, R.; Falkner, P.; Trautner, R.; Hamelin, M.; Simoes, F.; Jernej, I.; Pwa-Hasi

430

Superthermal electron processes in the upper atmosphere of Uranus: aurora and electroglow  

SciTech Connect

Strong ultraviolet emissions from the upper atmosphere of Uranus suggest that both auroral and electroglow phenomena are of significant aeronomical consequences in the structure of the upper atmosphere. Combined modeling and data analysis were performed to determine the effect of electroglow and auroral phenomena on the global heat and atomic hydrogen budgets in the Uranus upper atmosphere. The results indicate that the auroral and electroglow heat sources are not adequate to explain the high exospheric temperature observed at Uranus, but that the atomic hydrogen supplied by these processes is more than sufficient to explain the observations. The various superthermal electron distributions modeled have significantly different efficiencies for the various processes such as UV emission, heating, ionization, and atomic hydrogen production, and produce quite different H2 band spectra. However, additional information on the UV spectra and global parameters is needed before modeling can be used to distinguish between the possible mechanisms for electroglow.

Waite, J.H. Jr.; Chandler, M.O.; Yelle, R.V.; Sandel, B.R.

1987-01-01

431

Stochastic Car-Following Model for Explaining Nonlinear Traffic Phenomena  

NASA Astrophysics Data System (ADS)

There is a common time parameter for representing the sensitivity or the lag (response) time of drivers in many car-following models. In the viewpoint of traffic psychology, this parameter could be considered as the perception-response time (PRT). Generally, this parameter is set to be a constant in previous models. However, PRT is actually not a constant but a random variable described by the lognormal distribution. Thus the probability can be naturally introduced into car-following models by recovering the probability of PRT. For demonstrating this idea, a specific stochastic model is constructed based on the optimal velocity model. By conducting simulations under periodic boundary conditions, it is found that some important traffic phenomena, such as the hysteresis and phantom traffic jams phenomena, can be reproduced more realistically. Especially, an interesting experimental feature of traffic jams, i.e., two moving jams propagating in parallel with constant speed stably and sustainably, is successfully captured by the present model.

Meng, Jianping; Song, Tao; Dong, Liyun; Dai, Shiqiang

432

Critical phenomena and information geometry in black hole physics  

NASA Astrophysics Data System (ADS)

We discuss the use of information geometry in black hole physics and present the outcomes. The type of information geometry we utilize in this approach is the thermodynamic (Ruppeiner) geometry defined on the state space of a given thermodynamic system in equilibrium. The Ruppeiner geometry can be used to analyze stability and critical phenomena in black hole physics with results consistent with those from the Poincaré stability analysis for black holes and black rings. Furthermore other physical phenomena are well encoded in the Ruppeiner metric such as the sign of specific heat and the extremality of the solutions. The black hole families we discuss in particular in this manuscript are the Myers-Perry black holes.

Åman, Jan E.; Pidokrajt, Narit

2010-05-01

433

CLAYS AND CLAY INTERCALATION COMPOUNDS:Properties and Physical Phenomena  

NASA Astrophysics Data System (ADS)

The materials properties and physical phenomena exhibited by layered silicate clays and clay intercalation compounds, a subgroup of the general class of layered solids, are reviewed. The importance of layer rigidity is emphasized. Clays are compared and contrasted with the more familiar layered solids such as graphite and dichalcogenides. Some of the unusual structural features of clays including interstratification, swelling, and the lack of staging are discussed and explained qualitatively and quantitatively. Novel magnetic phenomena such as that associated with a disordered two-dimensional kagome antiferromagnet formed in synthetic clays and the effect of co-intercalated water on the crystal field-induced magnetic ordering in natural clays are described and analyzed. The vibrational excitations in clays are addressed in terms of lattice dynamical models for the phonon dispersion curves. The theoretical models are compared with experimental measurements including neutron scattering and Raman spectroscopy.

Solin, S. A.

1997-08-01

434

ESM of Ionic and Electrochemical Phenomena on the Nanoscale  

SciTech Connect

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 [1-4]. 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 as illustrated in Fig. 1. 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.

Kalinin, Sergei V [ORNL; Kumar, Amit [Pennsylvania State University; Balke, Nina [ORNL; McCorkle, Morgan L [ORNL; Guo, Senli [ORNL; Arruda, Thomas M [ORNL; Jesse, Stephen [ORNL

2011-01-01

435

Collective Phenomena in a Capacitively-Coupled Transmon Array  

NASA Astrophysics Data System (ADS)

The manifestation of condensed matter physics phenomena in interacting photon systems has been of recent theoretical interest. Under the circuit quantum electrodynamics (cQED) architecture, light-matter interactions can be engineered into a strong coupling regime and many-body interacting photon systems can be fabricated. In this experiment, we create a triangular array of 100 niobium transmon qubits on a sapphire substrate. Photon-mediated interactions are facilitated through capacitive coupling among the transmons, each with a charging energy of approximately 200MHz. Collective quantum behavior of the josephson-junction array is explored by measuring transmission across the array through input-output ports on the device itself as well as through a 3D cavity. This experiment is an important step towards realizing many-body, interacting quantum phenomena with photons.

Safira, Arthur; Underwood, Devin; Shanks, William; Raftery, James; Houck, Andrew

2012-02-01

436

Critical phenomena in heterogeneous k-core percolation.  

PubMed

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. PMID:23496486

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

2013-02-21

437

Numerical simulation on snow melting phenomena by CIP method  

NASA Astrophysics Data System (ADS)

A numerical scheme based on the C-CUP method to simulate melting phenomena in snow is proposed. To calculate these complex phenomena we introduce the phase change, elastic-plastic model, porous model, and verify each model by using some simple examples. This scheme is applied to a practical model, such as the snow piled on the insulator of electrical transmission line, in which snow is modeled as a compound material composed of air, water, and ice, and is calculated by elastic-plastic model. The electric field between two electrodes is solved by the Poisson equation giving the Joule heating in the energy conservation that eventually leads to snow melting. Comparison is made by changing the fraction of water in the snow to see its effect on melting process for the cases of applied voltage of 50 and 500 kV on the two electrodes.

Mizoe, H.; Yoon, S. Y.; Josho, M.; Yabe, T.

2001-04-01

438

Bayesian inference in the scaling analysis of critical phenomena  

NASA Astrophysics Data System (ADS)

To determine the universality class of critical phenomena, we propose a method of statistical inference in the scaling analysis of critical phenomena. The method is based on Bayesian statistics, most specifically, the Gaussian process regression. It assumes only the smoothness of a scaling function, and it does not need a form. We demonstrate this method for the finite-size scaling analysis of the Ising models on square and triangular lattices. Near the critical point, the method is comparable in accuracy to the least-square method. In addition, it works well for data to which we cannot apply the least-square method with a polynomial of low degree. By comparing the data on triangular lattices with the scaling function inferred from the data on square lattices, we confirm the universality of the finite-size scaling function of the two-dimensional Ising model.

Harada, Kenji

2011-11-01

439

Bayesian inference in the scaling analysis of critical phenomena.  

PubMed

To determine the universality class of critical phenomena, we propose a method of statistical inference in the scaling analysis of critical phenomena. The method is based on Bayesian statistics, most specifically, the Gaussian process regression. It assumes only the smoothness of a scaling function, and it does not need a form. We demonstrate this method for the finite-size scaling analysis of the Ising models on square and triangular lattices. Near the critical point, the method is comparable in accuracy to the least-square method. In addition, it works well for data to which we cannot apply the least-square method with a polynomial of low degree. By comparing the data on triangular lattices with the scaling function inferred from the data on square lattices, we confirm the universality of the finite-size scaling function of the two-dimensional Ising model. PMID:22181544

Harada, Kenji

2011-11-18

440

Autoscopic phenomena: case report and review of literature  

PubMed Central

Background Autoscopic phenomena are psychic illusory visual experiences consisting of the perception of the image of one's own body or face within space, either from an internal point of view, as in a mirror or from an external point of view. Descriptions based on phenomenological criteria distinguish six types of autoscopic experiences: autoscopic hallucination, he-autoscopy or heautoscopic proper, feeling of a presence, out of body experience, negative and inner forms of autoscopy. Methods and results We report a case of a patient with he-autoscopic seizures. EEG recordings during the autoscopic experience showed a right parietal epileptic focus. This finding confirms the involvement of the temporo-parietal junction in the abnormal body perception during autoscopic phenomena. We discuss and review previous literature on the topic, as different localization of cortical areas are reported suggesting that out of body experience is generated in the right hemisphere while he-autoscopy involves left hemisphere structures.

2011-01-01

441

Origin of Titan's Atmosphere  

NASA Astrophysics Data System (ADS)

Titan has remarkable features - a dense N2 atmosphere and hydrological cycles of CH4 - that are resemble to those of Earth. How did the atmosphere develop on Titan? Was its origin similar to that of Earth’s atmosphere? Although these questions remain unsolved, the Cassini-Huygens mission has provided important clues to understand the origin of Titan’s atmosphere. 1) The low abundance of primordial Ar indicates that Titan’s N2 would have been delivered in less volatile form, probably as NH3. 2) Titan’s interior may have been only partially differentiated or may consist of low-density rock materials, suggesting that the interior would have been cooler than previously thought. 3) Observations of Enceladus’ plume suggest that the chemical composition of building materials of the Saturnian satellites would have been similar to that of comets; i.e., CO2 would have been more abundant than CH4 in the satellitesimals. 4) Relatively young surface age, high levels of radiogenic Ar, and the absence of global CH4 oceans suggest recent degassing of CH4 from the interior. The observations 1) and 2) imply the importance of conversion process of NH3 to N2 on Titan while maintaining the interior cool. However, because all of proposed mechanisms converting NH3 to N2 (e.g., photolysis, shock heating, and impact) also dissociate primordial CO2 to CO, the lack of abundant CO in the present atmosphere is a big issue. Furthermore, if Titan’s interior is undifferentiated, this is apparently inconsistent with a view of young surface and recent degassing. So far, there is no model which explains the above observations consistently. In this paper, we review the proposed mechanisms to create a N2-CH4 atmosphere on Titan and discuss new problems raised by Cassini. Then, we will discuss a plausible history of Titan’s atmosphere on the basis of the new observations.

Sekine, Yasuhito

2012-04-01

442

Europa's Atmosphere: Production & Loss  

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

443

Seismically-induced sloshing phenomena in LMFBR reactor tanks  

SciTech Connect

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.

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

1982-01-01

444

Slope instability phenomena in Greece: A statistical analysis  

Microsoft Academic Search

The results of a statistical analysis on landslide phenomena in Greece are presented here. The task is based upon 800 case-histories\\u000a of landslide incidents, recorded up to 1986, retrieved from an original number of more than 1500 coded engineering reports\\u000a and studies. The object concerns village areas and the road network. It especially refers to their frequency distribution\\u000a and their

G. Koukis; C. Ziourkas

1991-01-01

445

The microwave absorbing phenomena of ferrite microwave absorbers  

Microsoft Academic Search

The complex permeability dispersions and the microwave absorbing phenomena are investigated in ferrite microwave absorbers. The complex permeability of hexagonal (Y- and Z-type) and spinel (NiZn ferrite and NiZnCo ferrite) ferrite microwave absorbers were measured in 200 MHz-16 GHz range. The theoretical matching frequencies are determined by plotting the measured complex permeability loci on the impedance matching solution map. One

J. Y. Shin; J. H. Oh

1993-01-01

446

Relaxation phenomena in lithium-ion-insertion cells  

Microsoft Academic Search

Relaxation phenomena in lithium-ion-insertion cells are modeled. Simulation results are presented for a dual lithium-ion-insertion cell and for a cell using a lithium-foil negative electrode. A period of relaxation after a charge or discharge can cause appreciable changes in the distribution of material in the insertion electrodes. Local concentration cells in the solution phase and an open-circuit potential that depends

Thomas F. Fuller; M. Doyle; J. S. Newman

1994-01-01

447

Inelastic x-ray scattering including resonance phenomena  

Microsoft Academic Search

The availability of intense synchrotron sources has recently made it possible to study weak interaction phenomena using inelastic x-ray scattering utilizing high resolution crystal spectrometers. The total resolution DeltaE\\/E of the order of 10-4 (better than 1 eV at 8 keV) is rather easily achievable using backscattering geometry and the measured count rates, especially from the low-Z elements, have turned

K. Haemaelaeinen; S. Manninen; W. Caliebe; C.-C. Kao; J. B. Hastings

1997-01-01

448

Entrainment and pull-through phenomena at a tee junction  

Microsoft Academic Search

Results from a series of experiments investigating the phenomena of liquid entrainment and vapor pull-through at a tee junction between a horizontal pipe and a small branchline are presented. These experiments were performed under conditions of stratified steam-water flows at 3.4, 4.4, and 6.2 MPa in the mainline, and critical flow through a nozzle installed in the branchline. Two orientations

1987-01-01

449

Metal-insulator transitions: New phenomena, new questions  

SciTech Connect

The metal-to-insulator transition has reemerged as one of the major concerns of condensed matter science, due partly to the discovery of high temperature superconductivity in doped correlation induced insulators. A number of related quantum (T=0) phenomena such as the superconductor-insulator and quantum Hall liquid-insulator transitions have been identified and explored. A considerable body of theoretical work also exists now. Some of this work and the questions it raises will be discussed here.

Ramakrishnan, T.V. (Indian Institute of Science, Bangalore (India))

1994-07-01

450

Obsessional phenomena and the development of imaginative competence.  

PubMed

Obsessional phenomena are discussed in the light of anxieties arising around the ages 8-12. Three cases of the disappearance of obsessional symptoms are then described. In one remarkable sequence of dreams preceded recovery; in another it was the establishment of a secure therapeutic bond; in the third it was falling in love. The capacity securely to differentiate between fantasy and reality is seen as an essential development element in the recovery from obsessionality. PMID:7104245

Holmes, J

1982-06-01

451

Popcorn phenomena in a ball grid array package  

Microsoft Academic Search

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

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

1994-01-01

452

Interfacial Phenomena: Linking Atomistic and Molecular Level Processes  

SciTech Connect

This was a grant to support travel for scientists to present data and interact with others in their field. Specifically, speakers presented their data in a session entitled “Interfacial Phenomena: Linking Atomistic and Macroscopic Properties: Theoretical and Experimental Studies of the Structure and Reactivity of Mineral Surfaces”. The session ran across three ½ day periods, March 30-31 2004. The session’s organizers were David J. Wesolowski andGordon E. Brown Jr. There were a total of 30 talks presented.

Jay A Brandes

2009-09-23

453

Dynamic critical phenomena in the AdS/CFT duality  

SciTech Connect

In critical phenomena, singular behaviors arise not only for thermodynamic quantities but also for transport coefficients. We study this dynamic critical phenomenon in the AdS/CFT duality. We consider black holes with a single R-charge in various dimensions and compute the R-charge diffusion in the linear perturbations. In this case, the black holes belong to model B according to the classification of Hohenberg and Halperin.

Maeda, Kengo; Natsuume, Makoto; Okamura, Takashi [Department of Engineering, Shibaura Institute of Technology, Saitama, 330-8570 (Japan); Theory Division, Institute of Particle and Nuclear Studies, KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki, 305-0801 (Japan); Department of Physics, Kwansei Gakuin University, Sanda, Hyogo, 669-1337 (Japan)

2008-11-15

454

An experimental investigation of iso-octane ignition phenomena  

Microsoft Academic Search

High-speed digital imaging has been used in rapid compression facility (RCF) studies to investigate ignition phenomena of iso-octane\\/air mixtures. Sequential images were captured for each experiment. The results indicate the existence of two ignition regimes. In one domain, ignition is rapid, typically less than 76 ?s, and ignition occurs simultaneously throughout the test volume. In the other domain, reaction fronts

S. M. Walton; X. He; B. T. Zigler; M. S. Wooldridge; A. Atreya

2007-01-01

455

Observations of mutual phenomena of Galilean's satellites at Catania  

NASA Astrophysics Data System (ADS)

The mutual phenomena between Jupiter and Saturn's satellites occur every half orbital period of these planets, when the Earth and the Sun cross their equatorial plane. At Physics and Astronomy Department of Catania University the events between Jupiter's satellites have been observed during the 1973, 1979, 1985/86, 1991, 1997 and 2009 campaigns and the ones between Saturn's satellites during the 1980/81 and 1995 campaigns. An overview of the main results obtained since 1973 is presented.

Fulvio, Daniele; Blanco, Carlo

2010-01-01

456

Chaotic phenomena of a periodic ion-acoustic soliton system  

Microsoft Academic Search

Chaotic phenomena of a periodic ion-acoustic solitons system that is composed of a series of ion-acoustic solitons have been observed in a double-plasma device. Periodic ion-acoustic solitons become unstable by the energy gain and energy loss of the solitons, and they become chaotic. Taking account of a pair of solitons in the system, the front soliton gains energy from the

T. Nagasawa

1999-01-01

457

Defluidization phenomena during the pyrolysis of two plastic wastes  

Microsoft Academic Search

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

Umberto Arena; Maria Laura Mastellone

2000-01-01

458

Video atlas of lateralising and localising seizure phenomena.  

PubMed

The detailed analysis of seizure semiology is an essential tool for diagnosing epileptic patients and is particularly important in the evaluation of patients considered for epilepsy surgery. The meticulous clinical observation of epileptic seizures provides information about the localisation and lateralisation of the symptomatogenic zone. Here, we present a video atlas showing a variety of ictal and postictal localising and lateralising phenomena. [Published with video sequences]. PMID:21636353

Stoyke, Cordula; Bilgin, Ozgür; Noachtar, Soheyl

2011-06-01

459

Interphase phenomena in silicon carbide single filament composites  

Microsoft Academic Search

A heat-treated SiC Nicalon NLP 201 fibre and four single-filament composites have been characterized by means of transmission electron microscopy techniques. Phenomena occurring before and during the chemical vapour deposition process have been investigated. First, the thermal decomposition of the fibre is explained. The SiC microcrystals which are in the fibre decompose giving a solid carbonaceous porous residue and a

Yves Maniette; A. Oberlin

1990-01-01

460

Simulating Microscopic Hydrodynamic Phenomena with Dissipative Particle Dynamics  

Microsoft Academic Search

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

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

1992-01-01

461

Recursively speaking: analyzing students' discourse of recursive phenomena  

Microsoft Academic Search

Al~tract Reoursion is a powerful concept, appearing in almost every introductory course in computer-soience (CS). CS ocbwators and eda~cational researohets often refer to diff;oulties in learning recursion, and suggest methods for toaohing recursion. However, the researoh literature barely addresses the unique ways in whioh students relate to this intcrdisciplinmy conoept and the particular learners' language exm~ning reoursive phenomena. The gap

Dalit Levy; Tami Lapidot

2000-01-01

462

Arterial wave propagation phenomena, ventricular work, and power dissipation  

Microsoft Academic Search

The effects of wave propagation phenomena, namely global reflection coefficient (?G[?]) and pulse wave velocity (c\\u000a ph), are studied in a model of the coupled left ventricle\\/arterial system. The left ventricle consists of a time-varying elastance,\\u000a while the arterial system is modeled as a single, uniform, elastic tube terminating in a complex load. Manipulation of model\\u000a parameters allowed for the

David S. Berger; John K. J. Li; Abraham Noordergraaf

1995-01-01

463

Treeing breakdown phenomena in MgO\\/LDPE nanocomposite material  

Microsoft Academic Search

To understand treeing phenomena in MgO\\/LDPE nanocomposite under ac voltage application, treeing breakdown properties and partial discharge inception voltage were investigated. Tree inception voltage increased with increasing filler content. Time to bridge counter electrode, time to breakdown and time-lag to breakdown also increased with addition of MgO nano-filler to LDPE. From these results, it becomes clear that the addition of

Masato Kawano; Yoshinobu Murakami; Masayuki Nagao; Yoitsu Sekiguchi; C. C. Reddy; Yoshinao Murata

2009-01-01

464

Recent LEP2 results on searches for new phenomena  

SciTech Connect

Recent results of searches for supersymmetric particles, Higgs bosons, and other new phenomena at LEP2 are summarized. These results are based on data and analyses from the four LEP experiments: ALEPH, DELPHI, L3, and OPAL. The data were collected during the summer and fall of 1996 with center-of-mass energies of 161 and 172 GeV. {copyright} {ital 1998 American Institute of Physics.}

Pan, Y. [Department of Physics, University of Wisconsin, 1150 University Ave., Madison, Wisconsin 53706 (United States)

1998-05-01

465

Resonant phenomena in conductor-backed coplanar waveguides (CBCPW's)  

Microsoft Academic Search

A thorough and systematic investigation of resonant phenomena in conductor-backed coplanar waveguides (CBCPWs) is reported. A rigorous three dimensional full-wave space-domain integral equation method accompanied by an S-parameter extraction technique is used. A series of measurements has been conducted to confirm the theoretical results. A patch-resonator model and a microstriplike (MSL) model are employed to understand the origin of resonance

Wen-Teng Lo; C.-K. C. Tzuang; S.-T. Peng; Ching-Cheng Tien; Chung-Chi Chang; Jenq-Wen Huang

1993-01-01

466

Replication Unreliability in Psychology: Elusive Phenomena or "Elusive" Statistical Power?  

PubMed Central

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.

Tressoldi, Patrizio E.

2012-01-01

467

Assessing decreased sensation and increased sensory phenomena in diabetic polyneuropathies.  

PubMed

Loss of sensation and increased sensory phenomena are major expressions of varieties of diabetic polyneuropathies needing improved assessments for clinical and research purposes. We provide a neurobiological explanation for the apparent paradox between decreased sensation and increased sensory phenomena. Strongly endorsed is the use of the 10-g monofilaments for screening of feet to detect sensation loss, with the goal of improving diabetic management and prevention of foot ulcers and neurogenic arthropathy. We describe improved methods to assess for the kind, severity, and distribution of both large- and small-fiber sensory loss and which approaches and techniques may be useful for conducting therapeutic trials. The abnormality of attributes of nerve conduction may be used to validate the dysfunction of large sensory fibers. The abnormality of epidermal nerve fibers/1 mm may be used as a surrogate measure of small-fiber sensory loss but appear not to correlate closely with severity of pain. Increased sensory phenomena are recognized by the characteristic words patients use to describe them and by the severity and persistence of these symptoms. Tests of tactile and thermal hyperalgesia are additional markers of neural hyperactivity that are useful for diagnosis and disease management. PMID:24158999

Dyck, Peter J; Herrmann, David N; Staff, Nathan P; Dyck, P James B

2013-11-01

468

Scaling phenomena in the Internet: Critically examining criticality  

PubMed Central

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