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1

Critical phenomena in atmospheric precipitation  

E-print Network

LETTERS Critical phenomena in atmospheric precipitation OLE PETERS1,2,3 * AND J. DAVID NEELIN3 1 convection and precipitation (the order parameter)--with correlated regions on scales of tens to hundreds the climatological mean by an order of magnitude or more. Moist convection and the accompanying precipitation have

Loss, Daniel

2

Numerical analysis and modeling of atmospheric phenomena  

NASA Technical Reports Server (NTRS)

For the past 22 years Grant NGR 22-009-727 has been supporting research in the Center for Meteorology and Physical Oceanography (and its predecessors) in a wide variety of diagnostic and modeling studies of atmospheric and ocean phenomena. Professor Jule Charney was the initial Principal Investigator. Professor Peter Stone joined him as co-Principal Investigator in 1975 and became the sole Principal Investigator in 1981. During its lifetime the Grant has supported in whole or in part 11 Master's theses, 14 Ph.D. theses, and 45 papers published in refereed scientific journals. All of these theses and papers (with bibliographic references) are listed below. All but one of the theses were used to fulfill the requirements for MIT (Massachusetts Institute of Technology) degrees and are available from the MIT libraries. The one exception is F. Chen's Ph.D. thesis which was for a Harvard degree and is available from the Harvard libraries. In addition to the work described in the citations listed below, the Grant has supported Research Assistant Amy Solomon during the past two years to carry out a study of how baroclinic adjustment is affected by vertical resolution, vertical temperature structure, and dissipation. Ms. Solomon plans to use this project for her Ph.D. thesis. Support for this project will continue under NASA Grant NAG 5-2490, 'The Factors Controlling Poleward Heat Transport in Climate Models.'

Stone, Peter H.

1994-01-01

3

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

E-print Network

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

Finney, William W., III (William Warner)

2014-01-01

4

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

E-print Network

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

Raja, Laxminarayan L.

5

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

Microsoft Academic Search

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

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

2010-01-01

6

Scale Invariance, Symmetries, Fractals, and Stochastic Simulations of Atmospheric Phenomena  

Microsoft Academic Search

Advances in remote sensing and in situ measurement techniques have revealed the full continuum of atmospheric motions and have underlined the importance of mesoscale processes. This paper examines the implications of three observed characteristics of mesoscale circulations: 1) the energy spectrum of the horizontal wind in the horizontal is of the form kh with h5\\/3 (k is a wavenumber); 2)

S. Lovejoy; D. Schertzer

1986-01-01

7

Double streamer phenomena in atmospheric pressure low frequency corona plasma  

SciTech Connect

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

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

2010-07-15

8

Phenomena of oscillations in atmospheric pressure direct current glow discharges  

SciTech Connect

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

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

2013-12-15

9

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

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

10

Atmospheric Phenomena  

Microsoft Academic Search

A clear, early spring evening, Thursday, 6-7 April 2000 had been keenly awaited for some months by amateur astronomers across\\u000a northwestern Europe and North America. On this occasion, the planets Mars, Saturn, and Jupiter would form a neat grouping\\u000a in the western sky together with the waxing crescent Moon in the growing twilight. Such conjunctions, when members of the\\u000a Solar

Neil Bone

11

Optical phenomena caused by radioactivity in the atmosphere and their use in remote ecological monitoring  

NASA Astrophysics Data System (ADS)

The paper analyzes secondary phenomena of atmospheric radioactive pollution caused by activity of the nuclear cycle enterprises. These effects being as indicators for remote diagnostics of a radio-activity are discussed. Excitation of a molecular and gas component in the air and various chemical reactions under the action of radiation have been considered. As a result of these reactions, new aerosol and gaseous components in the form of the exited atoms and ions appear in the atmosphere and relax with emission including microwave and optical wavelengths. The observable luminescence of the air during the emergency events at the nuclea power stations are long enough to be detected by modern receivers. Intensity of such radiation in a radioactive plume is estimated for ecological monitoring of the atmosphere. Aerosols appearing, as a result of UF6 hydrolysis, in the atmosphere and their behavior have been also shown to be detectable with remote sensing.

Chistyakova, Liliya K.

1999-11-01

12

A numerical weather prediction system designed to simulate atmospheric downburst phenomena  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

13

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

14

Discharge phenomena of an atmospheric pressure radio-frequency capacitive plasma source  

NASA Astrophysics Data System (ADS)

Discharge phenomena of a nonthermal atmospheric pressure plasma source have been studied. An atmospheric pressure plasma jet (APPJ) operates using rf power and produces a stable homogeneous discharge at atmospheric pressure. After breakdown, the APPJ operation is divided into two regimes, a "normal" operating mode when the discharge is stable and homogeneous, and a "failure" mode when the discharge converts into a filamentary arc. Current and voltage (I-V) characteristics and spatially resolved emission intensity profiles have been measured during the normal operating mode. These measurements show that the APPJ produces an alpha (?) mode rf capacitive discharge. Based upon a dimensional analysis using the observed I-V characteristics, a rough estimate is made for plasma density of 3×1011cm-3 and an electron temperature of 2 eV. In addition, the gas temperature of 120 °C has been spectroscopically measured inside the discharge. These plasma parameters indicate that the APPJ shows promise for various materials applications as it can produce substantial amounts of reactive species and avoid thermal damages, while having the advantage of atmospheric pressure operation.

Park, Jaeyoung; Henins, I.; Herrmann, H. W.; Selwyn, G. S.; Hicks, R. F.

2001-01-01

15

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

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

16

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

17

Transient luminous event phenomena and energetic particles impacting the upper atmosphere: Russian space experiment programs  

Microsoft Academic Search

In Russia several space missions are now planned to study transient luminous events in the atmosphere and high-energy charged particles at satellite altitudes. The experimental goal is to investigate the origin of the high-energy electrons and gamma ray quanta for specific transient luminous events (TLEs) and their role in the ionosphere-magnetosphere system. Simultaneous measurements of electrons at the orbit of

M. I. Panasyuk; V. V. Bogomolov; G. K. Garipov; O. R. Grigoryan; Y. I. Denisov; B. A. Khrenov; P. A. Klimov; L. L. Lazutin; S. I. Svertilov; N. N. Vedenkin; I. V. Yashin; S. I. Klimov; L. M. Zeleny; V. S. Makhmutov; Y. I. Stozkov; N. S. Svirzhevsky; V. V. Klimenko; E. A. Mareev; Y. V. Shlyugaev; V. E. Korepanov; I. H. Park; H. I. Salazar; H. Rothkaehl

2010-01-01

18

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

SciTech Connect

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

2012-01-15

19

Abnormal winter weather in Japan during 2012 controlled by large-scale atmospheric and small-scale oceanic phenomena  

NASA Astrophysics Data System (ADS)

Negative Arctic Oscillation (AO) and Western Pacific (WP) pattern indices persisted from October through December 2012. For the first time both the monthly AO and WP were negative for three consecutive months. Although negative AOs and WPs make Siberia, Eastern Asia, and Japan abnormally cold, Japan was warm in October 2012. The temperature of the Sea of Japan was a record-breaking high in October 2012. Heating by these very warm waters overwhelmed the cooling effect of the negative AO and WP in October, even though the Sea of Japan is small. Linear regression analyses showed that Japan tends to be warm in years when the Sea of Japan is warm. Consequently, the temperature over Japan is controlled by interannual variations of small-scale oceanic phenomena as well as by large-scale atmospheric patterns. Previous studies have ignored such small-scale oceanic influences on island temperatures.

Ando, Yuta; Ogi, Masayo; Tachibana, Yoshihiro

2014-05-01

20

Waves, shocks and non-stationary phenomena in the outer solar atmosphere  

NASA Technical Reports Server (NTRS)

The dynamics of the solar chromosphere, transition region and corona were investigated. The consequences of the solar dynamics on the formation of spectral features in solar atmosphere regions are discussed. Data mainly from the solar ultraviolet measurement of emitted radiation (SUMER) instrument, showing signatures of non-stationary processes, are presented. These data are compared to the predictions of numerical models of the chromosphere and transition region. The observations seem to support the importance of upwardly propagating acoustic shocks in the heating of the chromosphere.

Hansteen, V. H.

1997-01-01

21

Modeling of ocean-atmosphere interaction phenomena during the breaking of modulated wave trains  

NASA Astrophysics Data System (ADS)

Air water interaction phenomena taking place during the breaking of ocean waves are investigated here. The study is carried out by exploiting the combination between a potential flow method, which is used to describe the evolution of the wave system up to the onset of the modulational instability, and a two-fluids Navier-Stokes solver which describes the strongly non-linear air-water interaction taking place during breaking events. The potential flow method is based on a fully non-linear mixed Eulerian-Lagrangian approach, whereas the two-fluid model uses a level-set method for the interface capturing. The method is applied to study the evolution of a modulated wave train composed by a fundamental wave component with two side band disturbances. It is shown that breaking occurs when the initial steepness exceed a threshold value. Once the breaking starts, it is not just a single event but it is recurrent with a period associated to the group velocity. Results are presented in terms of free surface shapes, velocity and vorticity fields, energy and viscous dissipation. The analysis reveals the formation of large vortex structures in the air domain which are originated by the separation of the air flow at the crest of the breaking wave. The form drag associated to the flow separation process significantly contributes to the dissipation of the energy content of the wave system. The energy fraction dissipated by each breaking event is distinguished.

Iafrati, A.; Babanin, A.; Onorato, M.

2014-08-01

22

Spectral derates phenomena of atmospheric components on multi-junction CPV technologies  

NASA Astrophysics Data System (ADS)

The solar spectrum varies with atmospheric conditions and composition, and can have significant impacts on the output power performance of each junction in a concentrating solar photovoltaic (CPV) system, with direct implications on the junction that is current-limiting. The effect of changing solar spectrum on CPV module power production has previously been characterized by various spectral performance parameters such as air mass (AM) for both single and multi-junction module technologies. However, examinations of outdoor test results have shown substantial uncertainty contributions by many of these parameters, including air mass, for the determination of projected power and energy production. Using spectral data obtained from outdoor spectrometers, with a spectral range of 336nm-1715nm, this investigation examines precipitable water (PW), aerosol and dust variability effects on incident spectral irradiance. This work then assesses air mass and other spectral performance parameters, including a new atmospheric component spectral factor (ACSF), to investigate iso-cell, stacked multijunction and single-junction c-Si module performance data directly with measured spectrum. This will then be used with MODTRAN5® to determine if spectral composition can account for daily and seasonal variability of the short-circuit current density Jsc and the maximum output power Pmp values. For precipitable water, current results show good correspondence between the modeled atmospheric component spectral factor and measured data with an average rms error of 0.013, for all three iso-cells tested during clear days over a one week time period. Results also suggest average variations in ACSF factors with respect to increasing precipitable water of 8.2%/cmH2O, 1.3%/cmH2O, 0.2%/cmH2O and 1.8%/cmH2O for GaInP, GaAs, Ge and c-Si cells, respectively at solar noon and an AM value of 1.0. For ozone, the GaInP cell had the greatest sensitivity to increasing ozone levels with an ACSF variation of 0.07%/cmO3. For the desert dust wind study, consistent ACSF behavior between all iso-cells and c-Si was found, with only significant reductions beyond 40mph.

Armijo, Kenneth M.; Harrison, Richard K.; King, Bruce H.; Martin, Jeffrey B.

2014-09-01

23

Fractals in geophysics Geophysical phenomena of interest to geoscientists include both atmospheric and terrestrial related processes, which  

E-print Network

Preface Fractals in geophysics Geophysical phenomena of interest to geoscientists include both-fractal type. Recently, there has been much interdisciplinary interest in the application of geophysical of the spatio-temporal organization of geophysical phenomena from micro to macro levels [1­6]. Wider application

Rangarajan, Govindan

24

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

NASA Astrophysics Data System (ADS)

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

Gitle Hauge, Bjørn; Strand, Erling

2013-04-01

25

Paranormal phenomena  

NASA Astrophysics Data System (ADS)

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.

Gaina, Alex

1996-08-01

26

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

27

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

28

Hazardous Phenomena at Volcanoes  

USGS Publications Warehouse

Volcanoes generate a wide variety of phenomena that can alter the Earth's surface and atmosphere and endanger people and property. While most of the natural hazards illustrated and described in this fact sheet are associated with eruptions, some, like landslides, can occur even when a volcano is quiet. Small events may pose a hazard only within a few miles of a volcano, while large events can directly or indirectly endanger people and property tens to hundreds of miles away.

Myers, Bobbie M.; Brantley, Steven R.

1995-01-01

29

Transport Phenomena.  

ERIC Educational Resources Information Center

Discusses the problems created in graduate chemical engineering programs when students enter with a wide diversity of understandings of transport phenomena. Describes a two-semester graduate transport course sequence at the University of Notre Dame which focuses on fluid mechanics and heat and mass transfer. (TW)

McCready, Mark J.; Leighton, David T.

1987-01-01

30

Fluctuation phenomena  

SciTech Connect

Fluctuation phenomena are the ''tip of the iceberg'' revealing the existence, behind even the most quiescent appearing macroscopic states, of an underlying world of agitated, ever-changing microscopic processes. While the presence of these fluctuations can be ignored in some cases, e.g. if one is satisfied with purely thermostatic description of systems in equilibrium, they are central to the understanding of other phenomena, e.g. the nucleation of a new phase following the quenching of a system into the co-existence region. This volume contains a collection of review articles, written by experts in the field, on the subject of fluctuation phenomena. Some of the articles are of a very general nature discussing the modern mathematical formulation of the problems involved, while other articles deal with specific topics such as kinetics of phase transitions and conductivity in solids. The juxtaposition of the variety of physical situations in which fluctuation phenomena play an important role is novel and should give the reader an insight into this subject.

Montroll, E.W.; Lebowitz, J.L.

1986-01-01

31

Fog phenomena on Mars  

NASA Astrophysics Data System (ADS)

Mars Express High Resolution Stereo Camera (HRSC) images show impressive morning fog features in Valles Marineris and other regions of the surface of Mars. Temperatures have been determined, simultaneously to the imaging, by Mars Express Planetary Fourier Spectrometer (PFS). This identifies water ice rather than frozen CO 2 as the cause of the fog observations in Valles Marineris. Numerical estimates of the water vapor pressure, and the related atmospheric water content, at the frost-point (temperature of freezing or "re-sublimation" of water vapor) by a 1-dimensional planetary boundary layer model indicate that conditions in the planetary boundary layer can indeed temporarily favor the formation of ice particles. A systematic registration of sites of fog observations shows preferred regions and seasons on Mars for fog phenomena. In the first instance, the fog phenomena seem to be induced or supported by orographic effects but not directly by the distribution pattern of the atmospheric vapor or by the regional subsurface water content. This paper documents and thermodynamically verifies the existence of fog of water ice particles in the near-surface atmosphere of Mars.

Möhlmann, Diedrich T. F.; Niemand, Monika; Formisano, Vittorio; Savijärvi, Hannu; Wolkenberg, Paulina

2009-12-01

32

Calculation of the probability distributions of cm-wave and mm-wave attenuation on communications links, taking various atmospheric phenomena into account  

NASA Astrophysics Data System (ADS)

The paper presents a review of the literature on the current status of the problem of calculating radio-wave attenuation on communications links. The calculation of the mean values of probability distributions of radio-wave attenuation due to different factors is considered together with the ranges of possible variations of these distributions with respect to the calculated mean. Particular attention is given to the fading statistics of radio waves on surface links associated with anomalies of the air refractive index in the atmospheric surface layer.

Pozhidaev, V. N.

1992-10-01

33

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

34

Coupled Phenomena in Chemistry.  

ERIC Educational Resources Information Center

Various phenomena in chemistry and biology can be understood through Gibbs energy utilization. Some common phenomena in chemistry are explained including neutralization, hydrolysis, oxidation and reaction, simultaneous dissociation equilibrium of two weak acids, and common ion effect on solubility. (Author/SA)

Matsubara, Akira; Nomura, Kazuo

1979-01-01

35

Venus Atmosphere Dynamics Workshop  

Microsoft Academic Search

There has been considerable renewed interest in modeling the dynamics of the Venus atmosphere and getting to the bottom of the problem of what drives the atmospheric superrotation and other observed phenomena such as the polar vortex. The renewal of modeling activity has been inspired by the development of highly capable computers and spacecraft missions that have recently visited Venus

G. Schubert; C. C. Covey

2007-01-01

36

Meteor Phenomena and Bodies  

Microsoft Academic Search

Meteoroids can be observed at collision with the Earth's atmosphere as meteors. Different methods of observing meteors are\\u000a presented: besides the traditional counts of individual events, exact methods yield also data on the geometry of the atmospheric\\u000a trajectory; on the dynamics and ablation of the body in the atmosphere; on radiation; on the spectral distribution of radiation;\\u000a on ionization; on

Zden?k Ceplecha; Ji?Í Borovi?ka; W. Graham Elford; Douglas O. ReVelle; Robert L. Hawkes; VladimÍr Porub?an; Miloš Šimek

1998-01-01

37

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

38

Quantum phenomena in superconductors  

SciTech Connect

This paper contains remarks by the author on aspects of macroscopic quantum phenomena in superconductors. Some topics discussed are: Superconducting low-inductance undulatory galvanometer (SLUGS), charge imbalance, cylindrical dc superconducting quantum interference device (SQUIDS), Geophysics, noise theory, magnetic resonance with SQUIDS, and macroscopic quantum tunneling. 23 refs., 4 figs. (LSP)

Clarke, J.

1987-08-01

39

Neutron Star Phenomena  

NASA Technical Reports Server (NTRS)

Various phenomena involving neutron stars are addressed. Electron-positron production in the near magnetosphere of gamma-ray pulsars is discussed along with magnetic field evolution in spun-up and spinning-down pulsars. Glitches and gamma-ray central engines are also discussed.

Ruderman, Malvin

1998-01-01

40

Membrane Transport Phenomena (MTP)  

NASA Technical Reports Server (NTRS)

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

Mason, Larry W.

1997-01-01

41

Vortices in Saturn's upper atmosphere  

NASA Astrophysics Data System (ADS)

Saturn's magnetosphere exhibits phenomena with 10.7-hour periodicity that scientists do not fully understand. One proposed explanation is that twin vortices in the upper atmosphere at Saturn's north and south poles generate currents that drive the magnetosphere periodicity.

Balcerak, Ernie

2014-11-01

42

Wolf-Rayet phenomena  

NASA Technical Reports Server (NTRS)

The properties of stars showing Wolf-Rayet phenomena are outlined along with the direction of future work. Emphasis is placed on the characteristics of W-R spectra. Specifically the following topics are covered: the absolute visual magnitudes; the heterogeneity of WN spectra; the existence of transition type spectra and compositions the mass loss rates; and the existence of very luminous and possibly very massive W-R stars. Also, a brief overview of current understanding of the theoretical aspects of stellar evolution and stellar winds and the various scenarios that have been proposed to understand W-R spectra are included.

Conti, P. S.

1982-01-01

43

Time-Variable Phenomena in the Jovian System  

NASA Technical Reports Server (NTRS)

The current state of knowledge of dynamic processes in the Jovian system is assessed and summaries are provided of both theoretical and observational foundations upon which future research might be based. There are three sections: satellite phenomena and rings; magnetospheric phenomena, Io's torus, and aurorae; and atmospheric phenomena. Each chapter discusses time dependent theoretical framework for understanding and interpreting what is observed; others describe the evidence and nature of observed changes or their absence. A few chapters provide historical perspective and attempt to present a comprehensive synthesis of the current state of knowledge.

Belton, Michael J. S. (editor); West, Robert A. (editor); Rahe, Jurgen (editor); Pereyda, Margarita

1989-01-01

44

MULTISCALE PHENOMENA IN MATERIALS  

SciTech Connect

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

A. BISHOP

2000-09-01

45

Weld pool phenomena  

SciTech Connect

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

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

1994-09-01

46

Attoheat transport phenomena  

E-print Network

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

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

2009-06-09

47

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

48

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

49

Arcjet Cathode Phenomena  

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

50

Arcjet cathode phenomena  

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

51

Phenomena resulting from hypergolic contact  

NASA Astrophysics Data System (ADS)

Understanding hypergolic ignition is critical for the safe and successful operation of hypergolic engines. The complex coupling of physical and chemical processes during hypergolic ignition complicates analysis of the event. Presently, hypergolic ignition models cannot simulate liquid contact and mixing or liquid-phase chemical reactions, and rely on experimental results for validation. In some cases, chemical kinetics of hypergolic propellants and fluid dynamics of droplet collisions couple to produce unexpected phenomena. This research investigates contact between droplets and pools of liquid hypergolic propellants under various conditions in order to investigate these liquid-phase reactions and categorize the resulting interaction. During this experiment, 142 drop tests were performed to investigate phenomena associated with hypergolic contact of various propellants. A drop of fuel impacted a semi-ellipsoidal pool of oxidizer at varying impact velocities and impact geometries. The temperature, pressure, ambient atmosphere, and propellant quality were all controlled during the experiment, as these factors have been shown to influence hypergolic ignition delay. Three distinct types of impacts were identified: explosions, bounces, and splashes. The impact type was found to depend on the impact Weber number and impact angle. Splashes occurred above a critical Weber number of 250, regardless of impact angle. Explosions occurred for Weber numbers less than 250, and for impact angles less than seven degrees. If the impact angle was greater than seven degrees then the test resulted in a bounce. Literature related to explosions induced by hypergolic contact was reviewed. Explosions were observed to occur inconsistently, a feature that has never been addressed. Literature related to non-reactive splashing, bouncing, and coalescence was reviewed for insight into the explosion phenomenon. I propose that the dependence of impact angle on the transition between explosion and bounce impacts is partially responsible for the explosion inconsistency in literature. No explosions were observed for the alternative hypergolic propellants tested, which could be due to lower gas production rates or the absence of reactive intermediate species present in certain propellant chemistry. In either case, the fluid dynamics of the impact was consistent, but the chemical kinetics of the propellants were different, and presumably, the two did not couple as strongly. Based on the results, explosions appear to be a mixing driven process caused by the coupling between the fluid dynamics of the impact and the chemical kinetics of the propellants. Upon contact, the fuel drop merges with the oxidizer pool. Liquid-phase neutralization reactions produce enough heat to vaporize propellants, which then accumulate within a gas pocket inside the pool. Exothermic gas-phase reactions result in an explosion originating from within the propellant pool. In addition to investigation of the explosion phenomenon, high-speed videos were taken of the first microseconds of hypergolic contact to observe the liquid-phase chemical reactions in detail. The delay between contact and first gas production was measured to be between 20 and 200 microseconds for monomethylhydrazine and red fuming nitric acid. This delay provides insight into the speed of the liquid-phase chemical reactions, and has helped to calibrate liquid-based ignition models. This research has categorized different interactions resulting from hypergolic contact, and found that the impact Weber number and impact angle were the controlling parameters. I propose that slight changes in the impact angle went unobserved by previous researchers and were partially responsible for the explosion inconsistency in literature. Microsecond scale time delays were measured between contact and gas production and have been used to calibrate previously unknown rate constants of liquid-phase chemical reactions.

Forness, Jordan M.

52

Schizoid phenomena in substance abusers.  

PubMed

It is hypothesized that the spectrum of schizoid disorders, schizoid phenomena, and the underlying psychodynamics can often be found in the gamut of addictions and stand in the way of recovery. Features of schizoidness, the varieties of schizoid presentations, the etiology and pathogenesis of drug/alcohol abuse in the schizoid, and readily clinically apparent psychodynamic features are discussed. Schizoid phenomena can be dealt with effectively with an informed psychotherapy. PMID:12095001

Armstrong, Ralph H

2002-01-01

53

The Regional Atmospheric Modeling System (RAMS): Development for Parallel Processing Computer  

E-print Network

) of the planetary boundary layer. Its most frequent applications are to simulate atmospheric phenomenaThe Regional Atmospheric Modeling System (RAMS): Development for Parallel Processing Computer. Walko Department of Atmospheric Science, Colorado State University and Mission Research Corporation

Cirne, Walfredo

54

Teaching optical phenomena with Tracker  

NASA Astrophysics Data System (ADS)

Since the invention and dissemination of domestic laser pointers, observing optical phenomena is a relatively easy task. Any student can buy a laser and experience at home, in a qualitative way, the reflection, refraction and even diffraction phenomena of light. However, quantitative experiments need instruments of high precision that have a relatively complex setup. Fortunately, nowadays it is possible to analyse optical phenomena in a simple and quantitative way using the freeware video analysis software ‘Tracker’. In this paper, we show the advantages of video-based experimental activities for teaching concepts in optics. We intend to show: (a) how easy the study of such phenomena can be, even at home, because only simple materials are needed, and Tracker provides the necessary measuring instruments; and (b) how we can use Tracker to improve students’ understanding of some optical concepts. We give examples using video modelling to study the laws of reflection, Snell’s laws, focal distances in lenses and mirrors, and diffraction phenomena, which we hope will motivate teachers to implement it in their own classes and schools.

Rodrigues, M.; Simeão Carvalho, P.

2014-11-01

55

Spectres of short time atmospheric light phenomena:meteors  

NASA Astrophysics Data System (ADS)

The theory of radiation, the methods of processing (spectrophotometry) and the interpretation of the meteors spectra are given. The original observations as well and the processing of the spectrogrammes is discussed in the connection with influx of various elements to the Earth. The problems of the studiing of the meteoric plasma are outlined. The problems of the meteors explosions are discussed on the basis of the solutions of the kinetic equations. The book is designed for a wide cercle of readers, students and scientists as well. Tables: 14, Illustrations 43; Bibliography: 268

Smirnov, V. A.

56

Rendering Ghost Ships and Other Phenomena in Arctic Atmospheres  

E-print Network

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

Gutierrez, Diego

57

Global atmospheric changes.  

PubMed Central

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

Piver, W T

1991-01-01

58

Global atmospheric changes.  

PubMed

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

Piver, W T

1991-12-01

59

Scaling law in thermal phenomena  

E-print Network

In this paper the scaling law for the relaxation times in thermal phenomena is investigated. It is shown that dependent on the value of the parameter K=E/m(c\\alpha)^2,where E is the energy which is delivered to the system, m is the parton mass and \\alpha=1/137 for electromagnetic interaction and \\alpha=0.16 for strong interaction respectively, heat transport is diffusive, for K1. For the system with N partons the relaxation time is scaled as \\tau^N\\to N (\\hbar/(mc\\alpha)^2). Key words: Thermal phenomena, scaling

M. Kozlowski; J. Marciak-Kozlowska

2006-10-29

60

Abnormal pressures as hydrodynamic phenomena  

USGS Publications Warehouse

So-called abnormal pressures, subsurface fluid pressures significantly higher or lower than hydrostatic, have excited speculation about their origin since subsurface exploration first encountered them. Two distinct conceptual models for abnormal pressures have gained currency among earth scientists. The static model sees abnormal pressures generally as relict features preserved by a virtual absence of fluid flow over geologic time. The hydrodynamic model instead envisions abnormal pressures as phenomena in which flow usually plays an important role. This paper develops the theoretical framework for abnormal pressures as hydrodynamic phenomena, shows that it explains the manifold occurrences of abnormal pressures, and examines the implications of this approach. -from Author

Neuzil, C.E.

1995-01-01

61

Quantum Phenomena Observed Using Electrons  

SciTech Connect

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

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

2011-05-06

62

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

63

Graphene tests of Klein phenomena  

E-print Network

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

Stefano De Leo; Pietro Rotelli

2012-02-07

64

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

65

Gravitational Anomaly and Transport Phenomena  

Microsoft Academic Search

Quantum anomalies give rise to new transport phenomena. In particular, a magnetic field can induce an anomalous current via the chiral magnetic effect and a vortex in the relativistic fluid can also induce a current via the chiral vortical effect. The related transport coefficients can be calculated via Kubo formulas. We evaluate the Kubo formula for the anomalous vortical conductivity

Karl Landsteiner; Eugenio Megías; Francisco Pena-Benitez

2011-01-01

66

URANIUM PYROPHORICITY PHENOMENA AND PREDICTION  

Microsoft Academic Search

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

Martin G. Plys; Michael Epstein; Boro Malinovic

67

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

68

Astronomy and Atmospheric Optics  

NASA Astrophysics Data System (ADS)

The authors discusse the insuccess of the observation of the Total Eclipse of the Moon from 10 december 2011 in Romania and relate them with meteoconditions. Only a very short part of the last penumbral phase was observed, while the inital part and the totality was not observed due to very dense clouds. The change in color and brightness during this phase was signaled. Meanwhile, there is an area of science where clouds are of great use and interest. This area is Atmospheric optics, while the science which study clouds is meteorology. Clouds in combination with Solar and Moon light could give rise to a variety of strange, rare and unobvious phenomena in the atmosphere (sky), sometimes confused with Unidentified Flying Objects (UFO). The importance of meteorology for astronomy and atmospheric optics is underlined and an invitation to astronomers to use unfavourable days for athmospheric observations was sent. The web address of the site by Les Cowley, designed for atmospheric optics phenomena is contained in the text of the entry.

Cowley, Les; Gaina, Alex

2011-12-01

69

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

70

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

71

Meteorological phenomena in Western classical orchestral music  

NASA Astrophysics Data System (ADS)

The creative output of composers, writers, and artists is often influenced by their surroundings. To give a literary example, it has been claimed recently that some of the characters in Oliver Twist and A Christmas Carol were based on real-life people who lived near Charles Dickens in London. Of course, an important part of what we see and hear is not only the people with whom we interact, but also our geophysical surroundings. Of all the geophysical phenomena to influence us, the weather is arguably the most significant, because we are exposed to it directly and daily. The weather was a great source of inspiration for Monet, Constable, and Turner, who are known for their scientifically accurate paintings of the skies. But to what extent does weather inspire composers? The authors of this presentation, who are atmospheric scientists by day but amateur classical musicians by night, have been contemplating this question. We have built a systematic musical database, which has allowed us to catalogue and analyze the frequencies with which weather is depicted in a sample of classical orchestral music. The depictions vary from explicit mimicry using traditional and specialized orchestral instruments, through to subtle suggestions. We have found that composers are generally influenced by their own environment in the type of weather they choose to represent. As befits the national stereotype, British composers seem disproportionately keen to depict the UK's variable weather patterns and stormy coastline. Reference: Aplin KL and Williams PD (2011) Meteorological phenomena in Western classical orchestral music. Weather, 66(11), pp 300-306. doi:10.1002/wea.765

Williams, P. D.; Aplin, K. L.

2012-12-01

72

Transport phenomena in nanoporous materials.  

PubMed

Diffusion, that is, the irregular movement of atoms and molecules, is a universal phenomenon of mass transfer occurring in all states of matter. It is of equal importance for fundamental research and technological applications. The present review deals with the challenges of the reliable observation of these phenomena in nanoporous materials. Starting with a survey of the different variants of diffusion measurement, it highlights the potentials of "microscopic" techniques, notably the pulsed field gradient (PFG) technique of NMR and the techniques of microimaging by interference microscopy (IFM) and IR microscopy (IRM). Considering ensembles of guest molecules, these techniques are able to directly record mass transfer phenomena over distances of typically micrometers. Their concerted application has given rise to the clarification of long-standing discrepancies, notably between microscopic equilibrium and macroscopic non-equilibrium measurements, and to a wealth of new information about molecular transport under confinement, hitherto often inaccessible and sometimes even unimaginable. PMID:25123096

Kärger, Jörg

2015-01-12

73

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

74

Mathematical Modeling of Diverse Phenomena  

NASA Technical Reports Server (NTRS)

Tensor calculus is applied to the formulation of mathematical models of diverse phenomena. Aeronautics, fluid dynamics, and cosmology are among the areas of application. The feasibility of combining tensor methods and computer capability to formulate problems is demonstrated. The techniques described are an attempt to simplify the formulation of mathematical models by reducing the modeling process to a series of routine operations, which can be performed either manually or by computer.

Howard, J. C.

1979-01-01

75

Atmospheric propagation effects relevant to optical communications  

NASA Technical Reports Server (NTRS)

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

Shaik, K. S.

1988-01-01

76

Atmospheric Propagation Effects Relevant to Optical Communications  

NASA Technical Reports Server (NTRS)

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

Shaik, K. S.

1988-01-01

77

Transport phenomena in porous media  

NASA Astrophysics Data System (ADS)

The Advanced Study Institute on Fundamentals of Transport Phenomena in Porous Media, held July 14-23, 1985 in Newark, Del. and directed by Jacob Bear (Israel Institute of Technology, Haifa) and M. Yavuz Corapcioglu (City College of New York), under the auspices of NATO, was a sequel to the NATO Advanced Study Institute (ASI) held in 1982 (proceedings published as Fundamentals of Transport Phenomena in Porous Media, J. Bear, and M.Y. Corapcioglu (Ed.), Martinus Nijhoff, Dordrecht, the Netherlands, 1984). The meeting was attended by 106 participants and lecturers from 21 countries.As in the first NATO/ASI, the objective of this meeting—which was a combination of a conference of experts and a teaching institute— was to present and discuss selected topics of transport in porous media. In selecting topics and lecturers, an attempt was made to bridge the gap that sometimes exists between research and practice. An effort was also made to demonstrate the unified approach to the transport of mass of a fluid phase, components of a fluid phase, momentum, and heat in a porous medium domain. The void space may be occupied by a single fluid phase or by a number of such phases; each fluid may constitute a multicomponent system; the solid matrix may be deformable; and the whole process of transport in the system may take place under nonisothermal conditions, with or without phase changes. Such phenomena are encountered in a variety of disciplines, e.g., petroleum engineering, civil engineering (in connection with groundwater flow and contamination), soil mechanics, and chemical engineering. One of the goals of the 1985 NATO/ASI, as in the 1982 institute, was to bring together experts from all these disciplines and enhance communication among them.

Bear, Jacob; Corapcioglu, M. Yavuz

78

Sulfuric acid and amines in atmospheric clustering : first-principles investigations.  

E-print Network

??The physical phenomena involving minuscule atmospheric aerosol particles pose many important and currently unresolved questions. The research presented in this doctoral dissertation concentrates on one… (more)

Loukonen, Ville

2014-01-01

79

Gravitational anomaly and transport phenomena.  

PubMed

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

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

2011-07-01

80

Measurements design and phenomena discrimination  

E-print Network

The construction of measurements suitable for discriminating signal components produced by phenomena of different types is considered. The required measurements should be capable of cancelling out those signal components which are to be ignored when focusing on a phenomenon of interest. Under the hypothesis that the subspaces hosting the signal components produced by each phenomenon are complementary, their discrimination is accomplished by measurements giving rise to the appropriate oblique projector operator. The subspace onto which the operator should project is selected by nonlinear techniques in line with adaptive pursuit strategies.

Laura Rebollo-Neira

2009-08-05

81

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

82

Unstructured Adaptive Mesh MOL Solvers for Atmospheric Reacting  

E-print Network

phenomena". In general the effects of mesh resolution have been well noted by the atmospheric modellingUnstructured Adaptive Mesh MOL Solvers for Atmospheric Reacting Flow Problems M.Berzins, A to computational models of reacting flow arising from atmospheric applications. These computational models describe

Utah, University of

83

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

84

Fuzzy intervention in biological phenomena.  

PubMed

An important objective of modeling biological phenomena is to develop therapeutic intervention strategies to move an undesirable state of a diseased network toward a more desirable one. Such transitions can be achieved by the use of drugs to act on some genes/metabolites that affect the undesirable behavior. Due to the fact that biological phenomena are complex processes with nonlinear dynamics that are impossible to perfectly represent with a mathematical model, the need for model-free nonlinear intervention strategies that are capable of guiding the target variables to their desired values often arises. In many applications, fuzzy systems have been found to be very useful for parameter estimation, model development and control design of nonlinear processes. In this paper, a model-free fuzzy intervention strategy (that does not require a mathematical model of the biological phenomenon) is proposed to guide the target variables of biological systems to their desired values. The proposed fuzzy intervention strategy is applied to three different biological models: a glycolytic-glycogenolytic pathway model, a purine metabolism pathway model, and a generic pathway model. The simulation results for all models demonstrate the effectiveness of the proposed scheme. PMID:23221089

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

2012-01-01

85

EXPERT - Demonstrating Reentry Aerothermodinamics Phenomena from a System Perspective  

NASA Astrophysics Data System (ADS)

EXPERT is developed by the European Space Agency (ESA) in order to provide the scientific community with quality data on critical aero-thermodynamic phenomena encountered during hypersonic flights as well as to provide industry with system experience of re-entry vehicle manufacturing and development of hypersonic instrumentation. EXPERT is equipped with 14 experiments provided by several scientific institutions all around Europe. The experiments address major aerothermodinamics phenomena: TPS material characterization, surface catalysis and oxidation, plasma spectroscopy, laminar to turbulent transition, flow separation and reattachment, shock-boundary layer interactions, base flow characteristic and aerodynamic characterization of flap control surfaces. The paper focus on the status of the EXPERT project: the design activities and the on going manufacturing, the main challenges and the expected flight data results. EXPERT will benefit future atmospheric re- entry activities ranging from cargo to human orbital transportation systems as well as re-usable launchers and scientific probes.

Massobrio, F.; Passarelli, G.; Gavira-Izquierdo, J.; Ratti, F.

2011-08-01

86

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

E-print Network

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

Materna, Kathryn

2014-01-01

87

Onset phenomena in MPD thrusters  

NASA Technical Reports Server (NTRS)

An experimental study has clarified some aspects of MPD thruster onset phenomena. The steep increase in terminal voltage that occurs as the onset current is approached may have different causes, depending on the propellant injection geometry. For propellant injection at the cathode radius, terminal voltage increase corresponds to a growing anode fall voltage; for injection at a larger radius, the increase is related to the back emf in the near-cathode plasma. The formation of the onset current pattern within the arc has been mapped experimentally as the thruster responds to an input current step which rises from below onset to the onset value. The appearance of terminal voltage hash at onset correlates with the extension into the exhaust region of a significant fraction of the arc current.

Barnett, J. W.; Jahn, R. G.

1985-01-01

88

Unidentified phenomena - Unusual plasma behavior?  

NASA Astrophysics Data System (ADS)

The paper describes observations of a phenomenon belonging to the UFO category and the possible causes of these events. Special attention is given to an event which occurred during the night of September 19-20, 1974, when a huge 'star' was observed over Pertrozavodsk (Russia), consisting of a bright-white luminous center, emitting beams of light, and a less bright light-blue shell. The star gradually formed a cometlike object with a tail consisting of beams of light and started to descend. It is suggested that this event was related to cosmic disturbances caused by an occurrence of unusually strong solar flares. Other examples are presented that relate unusual phenomena observed in space to the occurrence of strong magnetic turbulence events.

Avakian, S. V.; Kovalenok, V. V.

1992-06-01

89

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

90

Interaction-induced dipoles and polarizabilities in diverse phenomena  

NASA Astrophysics Data System (ADS)

This report briefly reviews the contributions made by the collision or interaction induced spectroscopies, i.e., far infrared and infrared absorption, and Rayleigh and Raman light scattering, to a variety of phenomena. The topics include: gaseous systems, planetary atmospheres; multipole moments; collision induced dipoles and polarizabilities; intermolecular potentials, dimers; three-body and liquid state interactions; double and triple-transitions; interference of allowed and induced transitions; solid state systems; halo-organic complexes; charge fluctuations in water; ionic melts; electrolyte solutions; viscoelastic relaxation in simple liquids; and interaction-induced emission.

Birnbaum, George; Guillot, Bertrand

1997-01-01

91

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

92

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

93

Nonepileptic motor phenomena in the neonate  

PubMed Central

The newborn infant is prone to clinical motor phenomena that are not epileptic in nature. These include tremors, jitteriness, various forms of myoclonus and brainstem release phenomena. They are frequently misdiagnosed as seizures, resulting in unnecessary investigations and treatment with anticonvulsants, which have potentially harmful side effects. Unfortunately, there is a paucity of literature about many of these phenomena in the newborn, and some of the major textbooks refer to these events as nonepileptic seizures, leading to further confusion for the practitioner. The present paper aims to review these phenomena with special emphasis on differentiating them from epileptic seizures, and offers information on treatment and prognosis wherever possible. PMID:19436521

Huntsman, Richard James; Lowry, Noel John; Sankaran, Koravangattu

2008-01-01

94

Observation of Celestial Phenomena in Ancient China  

NASA Astrophysics Data System (ADS)

Because of the need for calendar-making and portent astrology, the Chinese were diligent and meticulous observers of celestial phenomena. China has maintained the longest continuous historical records of celestial phenomena in the world. Extraordinary or abnormal celestial events were particularly noted because of their astrological significance. The historical records cover various types of celestial phenomena, which include solar and lunar eclipses, sunspots, "guest stars" (novae or supernovae as we understand today), comets and meteors, and all kinds of planetary phenomena. These records provide valuable historical data for astronomical studies today.

Sun, Xiaochun

95

EDITORIAL: Quantum phenomena in Nanotechnology Quantum phenomena in Nanotechnology  

NASA Astrophysics Data System (ADS)

Twenty years ago the Institute of Physics launched the journal Nanotechnology from its publishing house based in the home town of Paul Dirac, a legendary figure in the development of quantum mechanics at the turn of the last century. At the beginning of the 20th century, the adoption of quantum mechanical descriptions of events transformed the existing deterministic world view. But in many ways it also revolutionised the progress of research itself. For the first time since the 17th century when Francis Bacon established inductive reasoning as the means of advancing science from fact to axiom to law, theory was progressing ahead of experiments instead of providing explanations for observations that had already been made. Dirac's postulation of antimatter through purely theoretical investigation before its observation is the archetypal example of theory leading the way for experiment. The progress of nanotechnology and the development of tools and techniques that enabled the investigation of systems at the nanoscale brought with them many fascinating observations of phenomena that could only be explained through quantum mechanics, first theoretically deduced decades previously. At the nanoscale, quantum confinement effects dominate the electrical and optical properties of systems. They also render new opportunities for manipulating the response of systems. For example, a better understanding of these systems has enabled the rapid development of quantum dots with precisely determined properties, which can be exploited in a range of applications from medical imaging and photovoltaic solar cells to quantum computation, a radically new information technology being currently developed in many labs worldwide. As the first ever academic journal in nanotechnology, {\\it Nanotechnology} has been the forum for papers detailing progress of the science through extremely exciting times. In the early years of the journal, the investigation of electron spin led to the formulation of quantum cellular automata, a new paradigm for computing as reported by Craig S Lent and colleagues (Lent C S, Tougaw P D, Porod W and Bernstein G H 1993 Nanotechnology 4 49-57). The increasingly sophisticated manipulation of spin has been an enduring theme of research throughout this decade, providing a number of interesting developments such as spin pumping (Cota E, Aguado R, Creffield C E and Platero G 2003 Nanotechnology 14 152-6). The idea of spin qubits, proposed by D Loss and D P DiVincenzo (1998 Phys. Rev. A 57 120), developed into an established option for advancing research in quantum computing and continues to drive fruitful avenues of research, such as the integrated superconductive magnetic nanosensor recently devised by researchers in Italy (Granata C, Esposito E, Vettoliere A, Petti L and Russo M 2008 Nanotechnology 19 275501). The device has a spin sensitivity in units of the Bohr magneton of 100 spin Hz-1/2 and has large potential for applications in the measurement of nanoscale magnetization and quantum computing. The advance of science and technology at the nanoscale is inextricably enmeshed with advances in our understanding of quantum effects. As Nanotechnology celebrates its 20th volume, research into fundamental quantum phenomena continues to be an active field of research, providing fertile pasture for developing nanotechnologies.

Loss, Daniel

2009-10-01

96

NASA/MSFC FY-81 Atmospheric Processes Research Review  

NASA Technical Reports Server (NTRS)

Progress in ongoing research programs and future plans for satellite investigations into global weather, upper atmospheric phenomena, and severe storms and local weather are summarized. Principle investigators and publications since June 1980 are listed.

Turner, R. E. (compiler)

1981-01-01

97

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

98

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 research is characterized by the inability to substantiate, reproduce, and verify findings. Our current research includes the analysis of lunar images taken with two Santa Barbara Instrument Group (SBIG) ST8-E CCD cameras mounted on two 0.36m Celestron telescopes. On one telescope, we are using a sodium filter, and on the other an H-alpha filter, imaging approximately one-third of the lunar surface. We are focusing on two regions: Hyginus and Ina. Ina is of particular interest because it shows evidence of recent activity (Schultz, P., Staid, M., Pieters, C. Nature, Volume 444, Issue 7116, pp. 184-186, 2006). A total of over 50,000 images have been obtained over approximately 35 nights and visually analyzed to search for changes. As of March, 2014, no evidence of TLPs has been found. We are currently developing a Matlab program to do image analysis to detect TLPs that might not be apparent by visual inspection alone.

Barker, Timothy; Farber, Ryan; Ahrendts, Gary

2014-06-01

99

Interference Phenomena in Quantum Information  

E-print Network

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

Martin Stefanak

2010-09-01

100

Avalanche Phenomena in Pore Draining  

NASA Astrophysics Data System (ADS)

Hysteresis curves measured for superfluid ^4He capillary condensation in Nuclepore membrane indicate deviations from the independent element model. Nuclepore is an interesting material to study since every pore threads the membrane from top to bottom, but non-trivial in the sense that pore intersections seem to play an important role in the hysteresis phenomena observed. Especially interesting in the hysteresis is the sharp draining which occurs as the pores first begin to empty. This has been seen in other hysteretic capillary systems.footnote J. H. Page, J. Liu, B. Abeles, H. W. Deckman, and D. A. Weitz, Phys. Rev. Letters 71, 1216 (1993), for example. We have observed the existence of steps, or avalanches(M. P. Lilly, P. T. Finley, and R. B. Hallock, Phys. Rev. Letters 71), 4186 (1993). , as large groups of pores (<~10^7 out of a total sample size of ~ 10^9 pores) empty in the steep, initial portion of the draining curve. By use of spatially separated detectors, we show that avalanches involve macroscopic (rather than just local) regions of the Nuclepore. We report measurements of the size distribution, duration, and spatial extent of the avalanche events.

Lilly, M. P.; Hallock, R. B.

1996-03-01

101

Precursor films in wetting phenomena  

E-print Network

The spontaneous spreading of non-volatile liquid droplets on solid substrates poses a classic problem in the context of wetting phenomena. It is well known that the spreading of a macroscopic droplet is in many cases accompanied by a thin film of macroscopic lateral extent, the so-called precursor film, which emanates from the three-phase contact line region and spreads ahead of the latter with a much higher speed. Such films have been usually associated with liquid-on-solid systems, but in the last decade similar films have been reported to occur in solid-on-solid systems. While the situations in which the thickness of such films is of mesoscopic size are rather well understood, an intriguing and yet to be fully understood aspect is the spreading of microscopic, i.e., molecularly thin films. Here we review the available experimental observations of such films in various liquid-on-solid and solid-on-solid systems, as well as the corresponding theoretical models and studies aimed at understanding their formation and spreading dynamics. Recent developments and perspectives for future research are discussed.

M. N. Popescu; G. Oshanin; S. Dietrich; A. -M. Cazabat

2012-05-07

102

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

103

Infrared experiments for spaceborne planetary atmospheres research. Full report  

NASA Technical Reports Server (NTRS)

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

1981-01-01

104

S-290 Unit 6: Atmospheric Stability  

NSDL National Science Digital Library

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

Comet

2010-03-02

105

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

106

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

107

Project Atmosphere Canada: Teacher's Guide  

NSDL National Science Digital Library

This teacher's guide from Project Atmosphere Canada is designed to promote an interest in meteorology among young people, and to encourage and foster the teaching of the atmospheric sciences and related topics in Canada. Topics include weather hazards such as hurricanes and thunderstorms; the use of radar and satellites in weather prediction; weather phenomena such as El Nino, wind patterns, high and low pressure, and clouds; sunlight, water vapor, and the upper atmopshere; and others. Each module features introductory material, concepts for basic understanding, and activities. This resource is also available in French.

108

Thermoelectric phenomena via an interacting particle system  

E-print Network

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

Maes, Christian

109

Psychophysiologic Phenomena in Multiple Personality and Hypnosis  

Microsoft Academic Search

This article demonstrates similarities in psychophysiologic phenomena found in Multiple Personality Disorder (MPD), individuals using hypnosis, and others who did not use hypnosis. The areas discussed are: allergic responses, dermatologic reactions, effects on the autonomic nervous system, seizure disorders, pain control, and healing. Examples from multiple personality cases are paralleled by citations of related phenomena from the hypnosis literature. Some

Bennett G. Braun

1983-01-01

110

Economic Agents and Markets as Emergent Phenomena  

E-print Network

, financial institutions,...) and agents representing various other social and environmental phenomena (eEconomic Agents and Markets as Emergent Phenomena LEIGH TESFATSION Department of Economics, Iowa State University, Ames, Iowa 50011-1070 3 December 2001 ABSTRACT An overview of recent work in agent

Tesfatsion, Leigh

111

Nanoflares, Spicules, and Other Small-Scale Dynamic Phenomena on the Sun  

NASA Technical Reports Server (NTRS)

There is abundant evidence of highly dynamic phenomena occurring on very small scales in the solar atmosphere. For example, the observed pr operties of many coronal loops can only be explained if the loops are bundles of unresolved strands that are heated impulsively by nanoflares. Type II spicules recently discovered by Hinode are an example of small-scale impulsive events occurring in the chromosphere. The exist ence of these and other small-scale phenomena is not surprising given the highly structured nature of the magnetic field that is revealed by photospheric observations. Dynamic phenomena also occur on much lar ger scales, including coronal jets, flares, and CMEs. It is tempting to suggest that these different phenomena are all closely related and represent a continuous distribution of sizes and energies. However, this is a dangerous over simplification in my opinion. While it is tru e that the phenomena all involve "magnetic reconnection" (the changin g of field line connectivity) in some form, how this occurs depends s trongly on the magnetic geometry. A nanoflare resulting from the interaction of tangled magnetic strands within a confined coronal loop is much different from a major flare occurring at the current sheet form ed when a CME rips open an active region. I will review the evidence for ubiquitous small-scale dynamic phenomena on the Sun and discuss wh y different phenomena are not all fundamentally the same.

Klimchuk, James

2010-01-01

112

Gustatory phenomena after upper dorsal sympathectomy.  

PubMed

In a series of 100 bilateral upper dorsal sympathectomies performed for palmar hyperhidrosis, gustatory sweating and other gustatory phenomena were reported by 68 of 93 patients (73%), followed up for an average of 1 1/2 years. These gustatory phenomena were quite different from physiologic gustatory sweating: a wide range of gustatory stimuli caused a variety of phenomena in varied locations. There was a negative correlation between the incidence of these phenomena and the occurrence of Horner's syndrome after sympathectomy. Analysis of our observations, and of clinical and experimental work of others, leads to the conclusion that gustatory phenomena after upper dorsal sympathectomy are the result of preganglionic sympathetic regeneration or collateral sprouting with aberrant synapses in the superior cervical ganglion. PMID:907534

Kurchin, A; Adar, R; Zweig, A; Mozes, M

1977-10-01

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

Atmospheric neutrons  

NASA Technical Reports Server (NTRS)

Contributions to fast neutron measurements in the atmosphere are outlined. The results of a calculation to determine the production, distribution and final disappearance of atmospheric neutrons over the entire spectrum are presented. An attempt is made to answer questions that relate to processes such as neutron escape from the atmosphere and C-14 production. In addition, since variations of secondary neutrons can be related to variations in the primary radiation, comment on the modulation of both radiation components is made.

Korff, S. A.; Mendell, R. B.; Merker, M.; Light, E. S.; Verschell, H. J.; Sandie, W. S.

1979-01-01

115

The Atmosphere  

Microsoft Academic Search

\\u000a The atmosphere is closely related to hydrology in a fundamental manner. It will, therefore, be appropriate to make a brief\\u000a introduction to the subject of atmosphere. As pointed out in chapter 1, atmosphere is a thin shell of gases, which is held\\u000a close to the earth by the gravitational attraction and is commonly called the air. These gases seem to

Pukh Raj Rakhecha; Vijay P. Singh

116

Atmospheric dust  

NSDL National Science Digital Library

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

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

2003-01-01

117

Pluto's atmosphere  

SciTech Connect

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

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

1989-01-01

118

Pluto's atmosphere  

NASA Technical Reports Server (NTRS)

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.

1989-01-01

119

Atmospheric Environment ] (  

E-print Network

of neutrally stratified atmospheric boundary layers over heterogeneous terrain. Water Resources Research 42, W (Atmospheric Environment Service, Canada) [Gong, W., Taylor, P.A., Do¨ rnbrack, A., 1996. Turbulent boundary-layer boundary-layer flow over a rough two-dimensional sinusoidal hill. Three different subgrid-scale (SGS

Stoll, Rob

120

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

121

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

122

Effects of electrostatic correlations on electrokinetic phenomena  

E-print Network

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 ...

Storey, Brian D.

123

Bayesian nonparametric learning of complex dynamical phenomena  

E-print Network

The complexity of many dynamical phenomena precludes the use of linear models for which exact analytic techniques are available. However, inference on standard nonlinear models quickly becomes intractable. In some cases, ...

Fox, Emily Beth

2009-01-01

124

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

125

The atmospheres of M dwarfs: Observations  

NASA Technical Reports Server (NTRS)

After presenting global properties of M dwarfs, the principal diagnostic of activity phenomena occurring in their atmosphere from the geometrical, energetic, and temporal points of view is stressed. Observations of sunspots, plages, flares, and activity cycles are presented. The major sources of activity are discussed with particular emphasis on the generation, intensification, and measurements of stellar magnetic fields.

Rodono, Marcello

1987-01-01

126

Reproductive phenomena of a sexual buffelgrass plant  

E-print Network

REPRODUCTIVE PHENOMENA OF A SEXUAL EUFFELGRASS PLANT A Thesis 3y Charles Millard Taliaferro . Submitted to the Graduate School of the A & M University of Texas in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... January 1964 Major Sub?'ect Agronomy REPRODUCTIVE PHENOMENA OF A SEXUAL BUFFELGRASS PLANT A Thesis Charles Millard Taliaferro Approved as to style and content by: (Chairman of Committee) (Head of Department) / ember) (Member) Memb er) January...

Taliaferro, Charles Millard

1965-01-01

127

A Comprehensive Analysis of Io's Atmosphere and Torus  

Microsoft Academic Search

This final report describes the results of our NASA\\/Planetary Atmospheres program studying the atmosphere of Jupiter's moon Io and the plasma torus which it creates. Io is the most volcanically active body in the solar system, and it is embedded deep within the strongest magnetosphere of any planet. This combination of circumstances leads to a host of scientifically compelling phenomena,

Nicholas M. Schneider

1999-01-01

128

The reaction of the atmosphere to solar disturbances  

NASA Technical Reports Server (NTRS)

The effect of solar flares on the thermosphere and the troposphere is investigated. It is found that during periods of geoeffect solar disturbances, there is a connection between phenomena in the upper and lower atmospheres and that variations in atmospheric parameters correlate with changes in the geomagnetic index.

Mikhnevich, V. V.

1979-01-01

129

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.

130

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

131

Atmospheric Mass  

NSDL National Science Digital Library

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

132

Thermodynamics and Transport Phenomena in High Temperature Steam Electrolysis Cells  

SciTech Connect

Hydrogen can be produced from water splitting with relatively high efficiency using high temperature electrolysis. This technology makes use of solid-oxide cells, running in the electrolysis mode to produce hydrogen from steam, while consuming electricity and high temperature process heat. The overall thermal-to-hydrogen efficiency for high temperature electrolysis can be as high as 50%, which is about double the overall efficiency of conventional low-temperature electrolysis. Current large-scale hydrogen production is based almost exclusively on steam reforming of methane, a method that consumes a precious fossil fuel while emitting carbon dioxide to the atmosphere. An overview of high temperature electrolysis technology will be presented, including basic thermodynamics, experimental methods, heat and mass transfer phenomena, and computational fluid dynamics modeling.

James E. O'Brien

2012-03-01

133

Atmospheric Environment ] (  

E-print Network

Elsevier Ltd. All rights reserved. Keywords: 3-D CTM; Tropospheric ozone; Air quality; Ozone precursors 1 or hemispheric ozone background as an external influence on Europe's air quality in the light of the continuingAtmospheric Environment ] (

134

Earth's Atmosphere  

NSDL National Science Digital Library

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

135

Atmospheric tritium  

SciTech Connect

Research progress for the year 1979 to 1980 are reported. Concentrations of tritiated water vapor, tritium gas and tritiated hydrocarbons in the atmosphere at selected sampling points are presented. (ACR)

Oestlund, H.G.; Mason, A.S.

1980-01-01

136

Spooky Phenomena in Two-Photon Processes  

NASA Astrophysics Data System (ADS)

A spooky phenomenon in two-photon coherent atomic absorption was discussed in 1980 [M. C. Li, Phys. Rev. A 22 (1980) 1323]. The absorption was initiated by two different laser sources. Classically, it is impossible for atoms to transit coherently in the absorption process, but quantum mechanically it is. This is one of the spooky phenomena in quantum mechanic. Around1990, there were very active experimental pursuits on a spooky phenomenon of two photons emitted from crystal parametric down conversion. The two-photon coherent atomic absorption process contained all basic ingredients as that in crystal parametric down conversion. However, the former arises from two different laser sources. The atom entangles two photons together and becomes a correlatior. The latter arises from a single laser source and two photons are entangled with each other at emission. These two spooky phenomena have been considered as disjointed. The present talk will review two spooky phenomena, and point out their similarities. The investigation on quantum spooky phenomena has led to quantum computing and quantum encryption. It is a hope that the present will stimulate the interest on bring in these two disjointed phenomena together and provide clues in advancing quantum computing and quantum encryption.

Li, Ming-Chiang

2006-05-01

137

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

138

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.

139

Static Friction Phenomena The following static friction phenomena have a direct dependency on velocity.  

E-print Network

Coulomb Friction Viscous Friction Stribeck Friction Static Friction Phenomena The following static friction phenomena have a direct dependency on velocity. Static Friction Model: Friction force opposes the direction of motion when the sliding velocity is zero. Coulomb Friction Model: Friction force

Simpkins, Alex

140

Quantum optical phenomena in semiconductor quantum dots  

E-print Network

Quantum optical phenomena are explored in artificial atoms well known as semiconductor quantum dots, in the presence of excitons and biexcitons. The analytical results are obtained using the conventional time-dependent perturbation technique. Numerical estimations are made for arealistic sample of CdS quantum dots in a high-Q cavity. Quantum optical phenomena such as quantum Rabi oscillations, photon statistics and collapse and revival of population inversion in exciton and biexciton states are observed. In the presence of biexcitons the collapse and revival phenomenon becomes faster due to the strong coupling of biexciton with cavity field.

J. Thomas Andrews

2002-11-22

141

Modeling of fundamental phenomena in welds  

SciTech Connect

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

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

1993-12-31

142

Coastal Meteorological Phenomena in CalNex  

NASA Astrophysics Data System (ADS)

Coastal meteorology plays an important role in air quality and climate in California. During the 2010 CalNex experiment, several phenomena affected the campaign observations. Among these were coastal eddies and outflow in Santa Monica Bay and the Los Angeles Bight; marine stratus and stratocumulus; and the land-sea breeze cycle on a variety of spatial scales, including transport from the San Francisco Bay Area into the Central Valley. In this presentation, we will describe these phenomena as they were seen in model forecasts and hindcast simulations, and compare those simulations to the relevant meteorological observations.

Angevine, W. M.; Brioude, J.

2010-12-01

143

Atmospheric instruments  

NASA Astrophysics Data System (ADS)

The National Science Foundation's (NSF) Division of Atmospheric Sciences is now accepting proposals requesting only specialized research equipment or instrumentation. The division, within the Directorate for Astronomical, Atmospheric, Earth, and Ocean Sciences (AAEO), aims to echo the theme of increased support for instrumentation of the NSF fiscal 1984 budget request to Congress.Guidelines for proposals for specialized research equipment and instrumentation are the same as those for research proposals. Each potential major user should describe the research projects for which the equipment will be used. Some institutional contribution is encouraged for the equipment proposals. For additional information on the submission of instrumentation proposals, contact the specific program director in the grant programs section (see list below) or in the new Upper Atmospheric Facilities program in NSF's Centers and Facilities section (see related news item this issue). Guidelines for proposal preparation can be found in NSF publication 81-79, Grants for Scientific and Engineering Research.

144

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

145

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

146

Time Fractional Formalism: Classical and Quantum Phenomena  

E-print Network

In this review, we present some fundamental classical and quantum phenomena in view of time fractional formalism. Time fractional formalism is a very useful tool in describing systems with memory and delay. We hope that this study can provide a deeper understanding of the physical interpretations of fractional derivative.

Hosein Nasrolahpour

2012-03-18

147

Velocity dependencies of some impact phenomena  

Microsoft Academic Search

A variety of cratering phenomena is discussed, primarily with respect to their dependencies on impact velocity. Based on experimental evidence, three impact regimes can be established, an elastic, a plastic, and a hydrodynamic regime. Within the hydrodynamic regime, the cartering process becomes uniform and independent of the impact velocity. It is mainly controlled by projectile and target densities and by

E. Schneider

1979-01-01

148

Towards Studying Transport Phenomena with Trapped Ions  

Microsoft Academic Search

Transport of charge and energy are key phenomena for many technological applications. The basic transport mechanisms, particularly in the quantum regime, offer rich physics. For instance, the conditions necessary for a fully quantum system to equilibrate are still under debate. We started an experimental effort to study energy transport in the quantum regime by placing single ions in microtraps formed

Michael Ramm; Thaned Pruttivarasin; Boyan Tabakov; Axel Kreuter; Nikos Daniilidis; Hartmut Häffner

2010-01-01

149

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

150

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...

151

University Students' Conceptions of Different Physical Phenomena  

Microsoft Academic Search

The purpose of this study was to examine how widespread university students' misconceptions of 3 physical phenomena were: namely, the motions of objects, seasonal changes, and aggregate changes of matter. One hundred and thirty-two university students completed a written questionnaire composed of 2 types of tasks. First, students evaluated the adequacy of a given explanation as compared to their knowledge

Eve Kikas

2003-01-01

152

Spooky Phenomena in Two-Photon Processes  

Microsoft Academic Search

A spooky phenomenon in two-photon coherent atomic absorption was discussed in 1980 [M. C. Li, Phys. Rev. A 22 (1980) 1323]. The absorption was initiated by two different laser sources. Classically, it is impossible for atoms to transit coherently in the absorption process, but quantum mechanically it is. This is one of the spooky phenomena in quantum mechanic. Around1990, there

Ming-Chiang Li

2006-01-01

153

Photo-Galvano-Mechanical Phenomena in Nanotubes  

E-print Network

Photo-Galvano-Mechanical Phenomena in Nanotubes Petr KraI\\ E. J. Mele2 , David Tomanek3 and Moshe elec- trical "ballistic current". The photo-currents can be generated even in centrosym- metric be also generated in semiconductor nanotubes or in higher bands of metallic nanotubes [2]. The photo

154

Beam coupling phenomena in fast kicker systems  

Microsoft Academic Search

Beam coupling phenomena have been observed in most fast kicker systems through out Brookhaven Collider-Accelerator complex. With ever-higher beam intensity, the signature of the beam becomes increasingly recognizable. The beam coupling at high intensity produced additional heat dissipation in high voltage modulator, thyratron grids and thyratron driver circuit sufficient to damage some components, and causes trigger instability. In this paper,

W. Zhang; L. A. Ahrens; J. Glenn; J. Sandberg; N. Tsoupas

2001-01-01

155

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

156

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

157

Interfacial phenomena and the ocular surface.  

PubMed

Ocular surface disorders, such as dry eye disease, ocular rosacea, and allergic conjunctivitis, are a heterogeneous group of diseases that require an interdisciplinary approach to establish underlying causes and develop effective therapeutic strategies. These diverse disorders share a common thread in that they involve direct changes in ocular surface chemistry as well as the rheological properties of the tear film and topographical attributes of the cellular elements of the ocular surface. Knowledge of these properties is crucial to understand the formation and stability of the preocular tear film. The study of interfacial phenomena of the ocular surface flourished during the 1970s and 1980s, but after a series of lively debates in the literature concerning distinctions between the epithelial and the glandular origin of ocular surface disorders during the 1990s, research into this important topic has declined. In the meantime, new tools and techniques for the characterization and functionalization of biological surfaces have been developed. This review summarizes the available literature regarding the physicochemical attributes of the ocular surface, analyzes the role of interfacial phenomena in the pathobiology of ocular surface disease, identifies critical knowledge gaps concerning interfacial phenomena of the ocular surface, and discusses the opportunities for the exploitation of these phenomena to develop improved therapeutics for the treatment of ocular surface disorders. PMID:24999101

Yañez-Soto, Bernardo; Mannis, Mark J; Schwab, Ivan R; Li, Jennifer Y; Leonard, Brian C; Abbott, Nicholas L; Murphy, Christopher J

2014-07-01

158

Exploratorium Exhibit and Phenomena Cross Reference  

NSDL National Science Digital Library

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

159

Theory of ultrafast phenomena in photoexcited semiconductors  

Microsoft Academic Search

The authors review the physics of ultrafast dynamics in semiconductors and their heterostructures, including both the observed experimental phenomena and the theoretical description of the processes. These are probed by ultrafast optical excitation, generating nonequilibrium states that can be monitored by time-resolved spectroscopy. Light pulses create coherent superpositions of states, and the dynamics of the associated phase relationships can be

Fausto Rossi; Tilmann Kuhn

2002-01-01

160

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

161

Atmospheric Chemistry  

NSDL National Science Digital Library

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

162

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

163

Lidar measurements of atmospheric constituents  

NASA Astrophysics Data System (ADS)

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

Weitkamp, Klaus C. H.

1996-12-01

164

Atmospheric Chemistry (Program Description)  

NSF Publications Database

... of Atmospheric Sciences Atmospheric Chemistry Description Supports research to measure and ... on the chemical reactions among atmospheric species; the sources and sinks of important trace gases ...

165

HAZARDOUS AIR POLLUTANTS: DRY-DEPOSITION PHENOMENA  

EPA Science Inventory

Dry-deposition rates were evaluated for two hazardous organic air pollutants, nitrobenzene and perchloroethylene, to determine their potential for removal from the atmosphere to three building material surfaces, cement, tar paper, and vinyl asbestos tile. Dry-deposition experimen...

166

Atmospheric Dust  

NSDL National Science Digital Library

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

Comet

2012-03-06

167

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

168

Kinetically controlled phenomena in dynamic combinatorial libraries.  

PubMed

Dynamic combinatorial libraries (DCLs) are collections of structurally related compounds that can interconvert through reversible chemical reaction(s). Such reversibility endows DCLs with adaptability to external stimuli, as rapid interconversion allows quick expression of those DCL components which best respond to the disturbing stimulus. This Tutorial Review focuses on the kinetically controlled phenomena that occur within DCLs. Specifically, it will describe dynamic chiral resolution of DCLs, their self-sorting under the influence of irreversible chemical and physical stimuli, and the autocatalytic behaviours within DCLs which can result in self-replicating systems. A brief discussion of precipitation-induced phenomena will follow and the review will conclude with the presentation of covalent organic frameworks (COFs)-porous materials whose synthesis critically depends on the fine tuning of the crystal growth and error correction rates within large DCLs. PMID:24445841

Ji, Qing; Lirag, Rio Carlo; Miljani?, Ognjen Š

2014-03-21

169

A review of impulsive phase phenomena  

NASA Technical Reports Server (NTRS)

A brief review is given of impulsive phase phenomena in support of the models used to compute the energies of the different components of the flares under study. The observational characteristics of the impulsive phase are discussed as well as the evidence for multi-thermal or non-thermal phenomena. The significance of time delays between hard X-rays and microwaves is discussed in terms of electron beams and Alfven waves, two-step acceleration, and secondary bursts at large distances from the primary source. Observations indicating the occurrence of chromospheric evaporation, coronal explosions, and thermal conduction fronts are reviewed briefly, followed by the gamma ray and neutron results. Finally, a preferred flare scenario and energy source are presented involving the interactions in a complex of magnetic loops with the consequent reconnection and electron acceleration.

Dejager, C.

1986-01-01

170

Probabilistic Dynamic Logic of Phenomena and Cognition  

E-print Network

The purpose of this paper is to develop further the main concepts of Phenomena Dynamic Logic (P-DL) and Cognitive Dynamic Logic (C-DL), presented in the previous paper. The specific character of these logics is in matching vagueness or fuzziness of similarity measures to the uncertainty of models. These logics are based on the following fundamental notions: generality relation, uncertainty relation, simplicity relation, similarity maximization problem with empirical content and enhancement (learning) operator. We develop these notions in terms of logic and probability and developed a Probabilistic Dynamic Logic of Phenomena and Cognition (P-DL-PC) that relates to the scope of probabilistic models of brain. In our research the effectiveness of suggested formalization is demonstrated by approximation of the expert model of breast cancer diagnostic decisions. The P-DL-PC logic was previously successfully applied to solving many practical tasks and also for modelling of some cognitive processes.

Vityaev, Evgenii; Perlovsky, Leonid; Smerdov, Stanislav

2011-01-01

171

Transport Phenomena During Equiaxed Solidification of Alloys  

NASA Technical Reports Server (NTRS)

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 a variety of microscale phenomena in the macroscopic transport equations. For the case of diffusion dominated solidification, a simplified set of model equations is examined in detail and validated through comparisons with numerous experimental data for both columnar and equiaxed dendritic growth. This provides a critical assessment of the various model assumptions. Models that include melt flow and solid phase transport are also discussed, although their validation is still at an early stage. Several numerical results are presented that illustrate some of the profound effects of convective transport on the final compositional and structural characteristics of a solidified part. Important issues that deserve continuing attention are identified.

Beckermann, C.; deGroh, H. C., III

1997-01-01

172

Breakdown phenomena in high power klystrons  

NASA Astrophysics Data System (ADS)

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

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

1988-03-01

173

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

174

Side writing phenomena in narrow track recording  

Microsoft Academic Search

Edge writing phenomena in narrow track recording on both well-oriented and planar isotropic thin-film recording media are studied by numerical micromagnetic modeling. Multiple dibit transition pairs are simulated and statistical properties are analyzed. The magnetization patterns of the simulated dibits are studied as well as the magnetic pole density distributions. It is found that, for the well-oriented film, the magnetic

Jian-Gang Zhu; Xiao-Guang Ye; T. C. Arnoldussen

1992-01-01

175

Search for collective phenomena in hadron interactions  

SciTech Connect

New results of the search for collective phenomena have been obtained and analyzed in the present report. The experimental studies are carried out on U-70 accelerator of IHEP in Protvino. It is suggested that these phenomena can be discovered at the energy range of 50-70 GeV in the extreme multiplicity region since the high-density matter can form in this very region. The collective behavior of secondary particles is considered to manifest itself in the Bose-Einstein condensation of pions, Vavilov-Cherenkov gluon radiation, excess of soft-photon yield, and other unique phenomena. The perceptible peak in the angular distribution has been revealed. It was interpreted as the gluon radiation and so the parton matter refraction index was determined. The new software was designed for the track reconstruction based on Kalman Filter technique. This algorithm allows one to estimate more precisely the track parameters (especially momentum). The search for Bose-Einstein condensation can be continued by using the selected events with the multiplicity of more than eight charged particles. The gluon dominance model predictions have shown good agreement with the multiplicity distribution at high multiplicity and confirmed the guark-gluon medium formation under these conditions.

Kokoulina, E. S., E-mail: kokoulin@sunse.jinr.ru; Nikitin, V. A., E-mail: nikitin@sunse.jinr.ru; Petukhov, Y. P., E-mail: Yuri.Petukhov@ihep.r [LHEP, JINR (Russian Federation); Karpov, A. V., E-mail: karpov@dm.komisc.ru; Kutov, A. Ya., E-mail: kutov@dm.komisc.r [Komi SC UrD RAS, Department of Mathematics (Russian Federation)

2010-12-15

176

Physical mechanism of membrane osmotic phenomena  

SciTech Connect

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

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

1996-09-01

177

Evaporation phenomena in f(T) gravity  

E-print Network

We formulate evaporation phenomena in a generic model of generalized teleparallel gravity in Weitzenbock spacetime with diagonal and non-diagonal tetrads basis. We also perform the perturbation analysis around the constant torsion scalar solution named Nariai spacetime which is an exact solution of field equations as the limiting case of the Schwarzschild-de Sitter and in the limit where two back hole and their cosmological horizons coincide. By a carefully analysis of the horizon perturbation equation, we show that (anti)evaporation can not happen if we use a diagonal tetrad basis. This result implies that a typical black hole in any generic form of generalized teleparallel gravity is frozen in its initial state if we use the diagonal tetrads. But in the case of non-diagonal tetrads the analysis is completely different. By a suitable non trivial non-diagonal tetrad basis we investigate the linear stability of the model under perturbations of the metric and torsion simultaneously. We observe that in spite of the diagonal case, both evaporation and anti evaporation can happen. The phenomena depend on the initial phase of the horizon perturbation. In the first mode when we restrict ourselves to the first lower modes the (anti)evaporation happens. So, in non-diagonal case the physical phenomena is reasonable. This is an important advantage of using non-diagonal tetrads instead of the diagonal ones. We also see that this is an universal feature, completely independent from the form of the model.

M. J. S. Houndjo; D. Momeni; R. Myrzakulov; M. E. Rodrigues

2013-05-08

178

Temporal Variations in Jupiter's Atmosphere  

NASA Technical Reports Server (NTRS)

In recent years, Jupiter has undergone many atmospheric changes from storms turning red to global. cloud upheavals, and most recently, a cornet or asteroid impact. Yet, on top of these seemingly random changes events there are also periodic phenomena, analogous to observed Earth and Saturn atmospheric oscillations. We will present 15 years of Hubble data, from 1994 to 2009, to show how the equatorial tropospheric cloud deck and winds have varied over that time, focusing on the F953N, F41 ON and F255W filters. These filters give leverage on wind speeds plus cloud opacity, cloud height and tropospheric haze thickness, and stratospheric haze, respectively. The wind data consistently show a periodic oscillation near 7-8 S latitude. We will discuss the potential for variations with longitude and cloud height, within the calibration limits of those filters. Finally, we will discuss the role that large atmospheric events, such as the impacts in 1994 and 2009, and the global upheaval of 2007, have on temporal studies, This work was supported by a grant from the NASA Planetary Atmospheres Program. HST observational support was provided by NASA through grants from Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under contract NAS5-26555.

Simon-Miller, Amy A.; Chanover, N. J.; Yanamandra-Fisher, P.; Hammel, H. B.; dePater, I.; Noll, K.; Wong, M.; Clarke, J.; Sanchez-Levega, A.; Orton, G. S.; Gonzaga, S.

2009-01-01

179

Acoustics in the Martian Atmosphere  

NASA Astrophysics Data System (ADS)

With the advent of the first attempt to deliver an acoustic microphone to the Martian surface aboard the failed Mars Polar Lander, there has been growing interests in the development of acoustic sensors to compliment scientific payloads on future spacecraft. Terrestrial scientist have been very successful in using infrasound (sound at frequencies below human detection, < 20 Hz) to detect and monitor atmospheric phenomena related to weather, tornadoes, mountain waves, microbaroms, ionospheric and auroral disturbances, and meteror/fireballs, as well as anthropogenic sources such as aircraft and nuclear explosions. Sounds on Mars at the audible frequencies (20 Hz to 20 kHz) will be severely attenuated due to viscous relaxation and thermal diffusion (collectively referred to as classical attenuation) which will be much more severe in the colder, less dense Martian atmosphere. Molecular relaxation of carbon dioxide will also contribute to the sound absorption in the lower audible frequencies. Since classical attenuation increases as a function of the frequency squared, at low infrasonic frequencies ( < 10 Hz), classical attenuation becomes less significant and sound absorption in the Martian atmosphere becomes more similar to that of the terrestrial atmosphere for the same frequencies. At these longer wavelengths, geometric spreading will dominate as the source of attenuation as the acoustic energy is spread out over an ever increasing spherical wave front. This implies that infrasound (10 to 0.01 Hz) will be a useful frequency range for future acoustic sensors developed for scientific payloads delivered to the Martian surface.

Williams, J.-P.

2000-10-01

180

Research on atmospheric volcanic emissions - An overview  

NASA Technical Reports Server (NTRS)

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.

1982-01-01

181

Features of optical phenomena connected with launches of solid-propellant ballistic rockets  

NASA Astrophysics Data System (ADS)

Specific optical phenomena observed in the upper atmosphere layers and connected with launches of powerful solid-propellant rockets are considered: the development of spherically symmetric gas-dust formations having the shape of an extending torus in the image plane and the formation of regions with intense blue-green (turquoise) glow observed under twilight conditions along a rocket's flight path. The development of clouds can be represented by the model of a strong explosion occurring at the stage separation of solid-propellant rockets in the upper atmosphere. A turquoise glow arises as a result of resonance scattering of solar radiation on AlO molecules that are formed when metallic aluminum in the composition of fuel interacts with atmosphere components and combustion products.

Platov, Yu. V.; Chernouss, S. A.; Alpatov, V. V.

2013-04-01

182

Enforced Development Of The Earth's Atmosphere  

E-print Network

We review some basic issues of the life-prescribed development of the Earth's system and the Earth's atmosphere and discourse the unity of Earth's type of life in physical and transcendental divisions. In physical division, we exemplify and substantiate the origin of atmospheric phenomena in the metabolic pathways acquired by the Earth's life forms. We are especially concerned with emergence of pro-life superficial environments under elaboration of the energy transformations. Analysis of the coupling phenomena of elaborated ozone-oxygen transformation and Arctic bromine explosion is provided. Sensing is a foundation of life and the Earth's life. We offer our explanation of human-like perception, reasoning and creativity. We suggest a number of propositions about association of transcendental and physical divisions and the purpose of existence. The study relates to the tradition of natural philosophy which it follows. The paper is suitable for the popular reading.

M. Iudin

2010-07-28

183

Atmospheric science  

NASA Technical Reports Server (NTRS)

The following types of experiments for a proposed Space Station Microgravity Particle Research Facility are described: (1) growth of liquid water drop populations; (2) coalescence; (3) drop breakup; (4) breakup of freezing drops; (5) ice nucleation for large aerosols or bacteria; (6) scavenging of gases, for example, SO2 oxidation; (7) phoretic forces, i.e., thermophoresis versus diffusiophoresis; (8) Rayleigh bursting of drops; (9) charge separation due to collisions of rimed and unrimed ice; (10) charged drop dynamics; (11) growth of particles in other planetary atmospheres; and (12) freezing and liquid-liquid evaporation. The required capabilities and desired hardware for the facility are detailed.

Hamill, Patrick; Ackerman, Thomas; Clarke, Antony; Goodman, Jindra; Levin, Zev; Tomasko, Martin; Toon, O. Brian; Whitten, Robert

1987-01-01

184

Collective Phenomena In Volume And Surface Barrier Discharges  

NASA Astrophysics Data System (ADS)

Barrier discharges are increasingly used as a cost-effective means to produce non-equilibrium plasmas at atmospheric pressure. This way, copious amounts of electrons, ions, free radicals and excited species can be generated without appreciable gas heating. In most applications the barrier is made of dielectric material. In laboratory experiments also the use of resistive, ferroelectric and semiconducting materials has been investigated, also porous ceramic layers and dielectric barriers with controlled surface conductivity. Major applications utilizing mainly dielectric barriers include ozone generation, surface cleaning and modification, polymer and textile treatment, sterilization, pollution control, CO2 lasers, excimer lamps, plasma display panels (flat TV screens). More recent research efforts are also devoted to biomedical applications and to plasma actuators for flow control. Sinu- soidal feeding voltages at various frequencies as well as pulsed excitation schemes are used. Volume as well as surface barrier discharges can exist in the form of filamentary, regularly patterned or laterally homogeneous discharges. Reviews of the subject and the older literature on barrier discharges were published by Kogelschatz (2002, 2003), by Wagner et al. (2003) and by Fridman et al. (2005). A detailed discussion of various properties of barrier discharges can also be found in the recent book "Non-Equilibrium Air Plasmas at Atmospheric Pressure" by Becker et al. (2005). The physical effects leading to collective phenomena in volume and surface barrier discharges will be discussed in detail. Special attention will be given to self-organization of current filaments. Main similarities and differences of the two types of barrier discharges will be elaborated.

Kogelschatz, U.

2010-07-01

185

Natural phenomena and the senses : linking memory and corporeal experience  

E-print Network

How could the experience of our rituals be made more meaningful? Our experience of ritual exists as an exchange between our memory and natural phenomena in a place over time. These place specific phenomena are filtered by ...

Pitts, William Edward, 1976-

2002-01-01

186

Positive and negative magnetoresistance phenomena observed in magnetic electrospun  

E-print Network

Positive and negative magnetoresistance phenomena observed in magnetic electrospun), and tunable negative and positive magnetoresistance switching phenomena were observed in the magnetic carbon. Introduction Giant magnetoresistance (GMR), rst discovered in alternating ferromagnetic iron and non

Guo, John Zhanhu

187

Microgravity Transport Phenomena Experiment (MTPE) Overview  

NASA Technical Reports Server (NTRS)

The Microgravity Transport Phenomena Experiment (MTPE) is a fluids experiment supported by the Fundamentals in Biotechnology program in association with the Human Exploration and Development of Space (BEDS) initiative. The MTP Experiment will investigate fluid transport phenomena both in ground based experiments and in the microgravity environment. Many fluid transport processes are affected by gravity. Osmotic flux kinetics in planar membrane systems have been shown to be influenced by gravimetric orientation, either through convective mixing caused by unstably stratified fluid layers, or through a stable fluid boundary layer structure that forms in association with the membrane. Coupled transport phenomena also show gravity related effects. Coefficients associated with coupled transport processes are defined in terms of a steady state condition. Buoyancy (gravity) driven convection interferes with the attainment of steady state, and the measurement of coupled processes. The MTP Experiment measures the kinetics of molecular migration that occurs in fluids, in response to the application of various driving potentials. Three separate driving potentials may be applied to the MTP Experiment fluids, either singly or in combination. The driving potentials include chemical potential, thermal potential, and electrical potential. Two separate fluid arrangements are used to study membrane mediated and bulk fluid transport phenomena. Transport processes of interest in membrane mediated systems include diffusion, osmosis, and streaming potential. Bulk fluid processes of interest include coupled phenomena such as the Soret Effect, Dufour Effect, Donnan Effect, and thermal diffusion potential. MTP Experiments are performed in the Microgravity Transport Apparatus (MTA), an instrument that has been developed specifically for precision measurement of transport processes. Experiment fluids are contained within the MTA fluid cells, designed to create a one dimensional flow geometry of constant cross sectional area, and to facilitate fluid filling and draining operations in microgravity. The fluid cells may be used singly for bulk solutions, or in a Stokes diaphragm configuration to investigate membrane mediated phenomena. Thermal and electrical driving potentials are applied to the experiment fluids through boundary plates located at the ends of the fluid cells. In the ground based instrument, two constant temperature baths circulate through reservoirs adjacent to the boundary plates, and establish the thermal environment within the fluid cells. The boundary plates also serve as electrodes for measurement and application of electrical potentials. The Fluid Manipulation System associated with the MTA is a computer controlled system that enables storage and transfer of experiment fluids during on orbit operations. The system is used to automatically initiate experiments and manipulate fluids by orchestrating pump and valve operations through scripted sequences. Unique technologies are incorporated in the MTA for measurement of fluid properties. Volumetric Flow Sensors have been developed for precision measurement of total fluid volume contained within the fluid cells over time. This data is most useful for measuring the kinetics of osmosis, where fluid is transported from one fluid cell to another through a semipermeable membrane. The MicroSensor Array has been designed to perform in situ measurement of several important fluid parameters, providing simultaneous measurement of solution composition at multiple locations within the experiment fluids. Micromachined sensors and interface electronics have been developed to measure temperature, electrical conductivity, pH, cation activity, and anion activity. The Profile Refractometer uses a laser optical system to directly image the fluid Index of Refraction profile that exists along the MTA fluid cell axis. A video system acquires images of the RI profile over time, and records the transport kinetics that occur upon application of chemical, thermal, or electrical driving potentials. Image proces

Mason, Larry W.

1999-01-01

188

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

189

Fast Particle Methods for Multiscale Phenomena Simulations  

NASA Technical Reports Server (NTRS)

We are developing particle methods oriented at improving computational modeling capabilities of multiscale physical phenomena in : (i) high Reynolds number unsteady vortical flows, (ii) particle laden and interfacial flows, (iii)molecular dynamics studies of nanoscale droplets and studies of the structure, functions, and evolution of the earliest living cell. The unifying computational approach involves particle methods implemented in parallel computer architectures. The inherent adaptivity, robustness and efficiency of particle methods makes them a multidisciplinary computational tool capable of bridging the gap of micro-scale and continuum flow simulations. Using efficient tree data structures, multipole expansion algorithms, and improved particle-grid interpolation, particle methods allow for simulations using millions of computational elements, making possible the resolution of a wide range of length and time scales of these important physical phenomena.The current challenges in these simulations are in : [i] the proper formulation of particle methods in the molecular and continuous level for the discretization of the governing equations [ii] the resolution of the wide range of time and length scales governing the phenomena under investigation. [iii] the minimization of numerical artifacts that may interfere with the physics of the systems under consideration. [iv] the parallelization of processes such as tree traversal and grid-particle interpolations We are conducting simulations using vortex methods, molecular dynamics and smooth particle hydrodynamics, exploiting their unifying concepts such as : the solution of the N-body problem in parallel computers, highly accurate particle-particle and grid-particle interpolations, parallel FFT's and the formulation of processes such as diffusion in the context of particle methods. This approach enables us to transcend among seemingly unrelated areas of research.

Koumoutsakos, P.; Wray, A.; Shariff, K.; Pohorille, Andrew

2000-01-01

190

Oscillating heat pipe simulation considering dryout phenomena  

NASA Astrophysics Data System (ADS)

In heat transport devices such as oscillating heat pipe (OHP), dryout phenomena is very important and avoided in order to give the optimum performance. However, from the previous studies (including our studies), the dryout phenomena in OHP and its mechanism are still unclear. In our studies of OHP (Senjaya and Inoue in Appl Thermal Eng 60:251-255, 2013; Int J Heat Mass Transfer 60:816-824, 2013; Int J Heat Mass Transfer 60:825-835, 2013), we introduced the importance and roles of liquid film in the operating principle of OHP. In our previous simulation, the thickness of liquid film was assumed to be uniform along a vapor plug. Then, dryout never occurred because there was the liquid transfer from the liquid film in the cooling section to that in the heating section. In this research, the liquid film is not treated uniformly but it is meshed similarly with the vapor plugs and liquid slugs. All governing equations are also solved in each control volume of liquid film. The simulation results show that dryout occurs in the simulation without bubble generation and growth. Dryout is started in the middle of vapor plug, because the liquid supply from the left and right liquid slugs cannot reach until the liquid film in the middle of vapor plug, and propagates to the left and right sides of a vapor plug. By inserting the bubble generation and growth phenomena, dryout does not occur because the wall of heating section is always wetted during the bubble growth and the thickness of liquid film is almost constant. The effects of meshing size of liquid film and wall temperature of heating section are also investigated. The results show that the smaller meshing size, the smaller liquid transfer rate and the faster of dryout propagation. In the OHP with higher wall temperature of heating section, dryout and its propagation also occur faster.

Senjaya, Raffles; Inoue, Takayoshi

2014-10-01

191

Complex Synchronization Phenomena in Ecological Systems  

NASA Astrophysics Data System (ADS)

Ecological and biological systems provide us with many striking examples of synchronization phenomena. Here we discuss a number of intriguing cases and attempt to explain them taking advantage of a modelling framework. One main focus will concern synchronized ecological end epidemiological cycles which have Uniform Phase growth associated with their regular recurrence, and Chaotic Amplitudes - a feature we term UPCA. Examples come from different areas and include decadal cycles of small mammals, recurrent viral epidemics such as childhood infections (eg., measles), and seasonally driven phytoplankton blooms observed in lakes and the oceans. A more detailed theoretical analysis of seasonally synchronized chaotic population cycles is presented.

Stone, Lewi; Olinky, Ronen; Blasius, Bernd; Huppert, Amit; Cazelles, Bernard

2002-07-01

192

Advances in modelling of condensation phenomena  

SciTech Connect

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

Liu, W.S.; Zaltsgendler, E. [Ontario Hydro Nuclear, Toronto (Canada); Hanna, B. [Atomic Energy of Canada Limited, Pinawa, Manitoba (Canada)

1997-07-01

193

Petrovay: Solar physics Activity phenomena 1 Overall structure: umbra + penumbra.  

E-print Network

Petrovay: Solar physics Activity phenomena 1 SUNSPOTS Overall structure: umbra + penumbra in decaying spots (hysteresis-like behaviour). #12;Petrovay: Solar physics Activity phenomena 1 Temperature: the effect is probably not real. #12;Petrovay: Solar physics Activity phenomena 1 Magnetic field: B0 2500

Petrovay, Kristóf

194

Petrovay: Solar physics Activity phenomena 2 SOLAR PROMINENCES  

E-print Network

Petrovay: Solar physics Activity phenomena 2 SOLAR PROMINENCES History: 12th­18th century: sporadic (Zirin & Severny) #12;Petrovay: Solar physics Activity phenomena 2 Classification Eruptive prominence in a sunspot. From their end matter flows into spot. #12;Petrovay: Solar physics Activity phenomena 2 Filaments

Petrovay, Kristóf

195

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

196

Black Holes Admitting Strong Resonant Phenomena  

E-print Network

High-frequency twin peak quasiperiodic oscillations (QPOs) are observed in four microquasars, i.e., Galactic black hole binary systems, with frequency ratio very close to 3:2. In the microquasar GRS 1915+105, the structure of QPOs exhibits additional frequencies, and more than two frequencies are observed in the Galaxy nuclei Sgr A*, or in some extragalactic sources (NGC 4051, MCG-6-30-15 and NGC 5408 X-1). The observed QPOs can be explained by a variety of the orbital resonance model versions assuming resonance of oscillations with the Keplerian frequency or the vertical epicyclic frequency, and the radial epicyclic frequency, or some combinations of these frequencies. Generally, different resonances could arise at different radii of an accretion disc. However, we have shown that for special values of dimensionless black hole spin strong resonant phenomena could occur when different resonances can be excited at the same radius, as cooperative phenomena between the resonances may work in such situations. The special values of black hole spin are determined for triple frequency ratio sets \

Zdenek Stuchlik; Andrea Kotrlova; Gabriel Torok

2008-12-23

197

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

198

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

199

Unexpected Phenomena in Contact-Line Dynamics  

NASA Astrophysics Data System (ADS)

We report several novel phenomena in contact-line and fingering dynamics of macroscopic spinning drops and gravity-driven films with dimensions larger than the capillary length. Contrary to general expectation, we observe that the speed of glycerin finger increases with increasing viscosity at high viscosity and low frequencies of rotation. Completely wetting Dow Corning 200 Fluid spreads faster over dry rather than prewetted plane. These phenomena could be explained by an interesting "double role" of contact line resistance. The larger resistance at some locations (at wedge segments of the finger head) or time (during flow initiation) results in larger liquid accumulation and, consequently, increases the subsequent rate of spreading. This also results in an increase in front thicknesses that we have detected in the spinning drop and gravity-driven fingering experiments. In the case of complete wetting, intermolecular forces, which are comparable to the main driving force (gravity), seem to be powerful enough to exceed viscous dissipation in a wedge and hence remove this accelerating effect. Thus, contact line could not only add resistance to flow, but also provide an appreciable driving force in macroscopic fronts, even under forced spreading conditions.

Indeikina, A.; Agarwal, A.; Veretennikov, I.; Chang, H.-C.

1998-11-01

200

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

201

Investigations of atmospheric dynamics using a CW Doppler sounder array  

NASA Technical Reports Server (NTRS)

A three-dimensional CW Doppler sounding system currently under operation at the NASA-Marshall Space Flight Center, Alabama is described. The properties of the neutral atmosphere are discussed along with the theory of Doppler sounding technique. Methods of data analyses used to investigate the dynamical phenomena at the ionospheric heights are presented and suggestions for future investigations provided.

Rao, G. L.

1974-01-01

202

Transient Phenomena: Opportunities for New Discoveries  

NASA Technical Reports Server (NTRS)

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

Lazio, T. Joseph W.

2010-01-01

203

Surfactant-based critical phenomena in microgravity  

NASA Technical Reports Server (NTRS)

The objective of this research project is to characterize by experiment and theoretically both the kinetics of phase separation and the metastable structures produced during phase separation in a microgravity environment. The particular systems we are currently studying are mixtures of water, nonionic surfactants, and compressible supercritical fluids at temperatures and pressures where the coexisting liquid phases have equal densities (isopycnic phases). In this report, we describe experiments to locate equilibrium isopycnic phases and to determine the 'local' phase behavior and critical phenomena at nearby conditions of temperature, pressure, and composition. In addition, we report the results of preliminary small angle neutron scattering (SANS) experiments to characterize microstructures that exist in these mixtures at different fluid densities.

Kaler, Eric W.; Paulaitis, Michael E.

1994-01-01

204

Critical phenomena at diamagnetic phase transitions  

NASA Astrophysics Data System (ADS)

The critical phenomena near diamagnetic phase transitions and in the domain phase are considered. Possibilities of the soft-mode existence and the static critical effect in susceptibility related to the appearance of Condon domains in aluminium are discussed. The constructed phase diagram and the temperature behaviour of the susceptibility give the value of the phase-transition temperature observed in aluminium. We present the temperature dependence of the magnetisation in each domain being the order parameter of the diamagnetic phase transition and confirming the softening of the orbital magnon-mode in aluminium. Calculations of the spectral density of excitations at diamagnetic phase transitions are made in order to explain the critical growth of the helicon damping observed in aluminium. The temperature dependence of the damping coincides with that measured in aluminium. The calculated magnetic-induction splitting due to Condon domains turns out to be close to that estimated in muon rotation spectroscopy experiment.

Gordon, A.; Logoboy, N.; Joss, W.

2004-12-01

205

Magnetostatic critical-point phenomena of Fe  

NASA Astrophysics Data System (ADS)

The magnetostatic critical-point phenomena of a highly pure polycrystalline Fe sphere (99.999% pure) have been first investigated by a vibrating sample magnetometer for the applied field from 0 to 8 kOe. The kink point locus was observed for the whole critical region. The critical temperature, the spontaneous magnetization, and the zero-field susceptibility were determined without data extrapolations. The Curie temperature and the critical indices were obtained to be: Tc=1042.98±0.02 K, ?=0.352±0.005 for ?=4×10-5-6×10-3, ?=1.269±0.005 for ?=2×10-4-2×10-2, and ?=4.20±0.05. ? neither agrees with the 3d Ising model nor with the 3d Heisenberg model, and ? fits between the two models. These indices satisfy the Griffith's inequality, ?'??(?-1). The critical equation of state was given by the same form as that for Ni.

Tanaka, Toshiro; Miyatani, Kazuo

1997-12-01

206

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

207

Reversion phenomena of Cu-Cr alloys  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

208

Single event phenomena: Testing and prediction  

NASA Technical Reports Server (NTRS)

Highly integrated microelectronic devices are often used to increase the performance of satellite systems while reducing the system power dissipation, size, and weight. However, these devices are usually more susceptible to radiation than less integrated devices. In particular, the problem of sensitivity to single event upset and latchup is greatly increased as the integration level is increased. Therefore, a method for accurately evaluating the susceptibility of new devices to single event phenomena is critical to qualifying new components for use in space systems. This evaluation includes testing devices for upset or latchup and extrapolating the results of these tests to the orbital environment. Current methods for testing devices for single event effects are reviewed, and methods for upset rate prediction, including a new technique based on Monte Carlo simulation, are presented.

Kinnison, James D.

1992-01-01

209

Directed polymer melts and quantum critical phenomena  

SciTech Connect

The statistical mechanics of directed linelike objects, such as directed polymers in an external field, strands of dipoles in both ferro- and electrorheological fluids, and flux lines in high-[Tc] superconductors, bears a close resemblance to the quantum mechanics of bosons in 2 + 1 dimensions. The authors show that single-component and binary mixture critical phenomena in these systems are in the universality class of three-dimensional uniaxial dipolar ferromagnets and ferroelectrics. The results also apply to films of two superfluid species undergoing phase separation well below their [lambda]-points near T = 0. In the case of directed polymers and electrorheological fluids they analyze the effects of free ends occurring in the sample as well as a novel directionally-dependent compressibility. 31 refs., 7 figs.

Kamien, R.D.; Nelson, D.R. (Harvard Univ., Cambridge, MA (United States))

1993-04-01

210

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

211

Boundary quantum critical phenomena with entanglement renormalization  

SciTech Connect

We propose the use of entanglement renormalization techniques to study boundary critical phenomena on a lattice system. The multiscale entanglement renormalization ansatz (MERA), in its scale invariant version, offers a very compact approximation to quantum critical ground states. Here we show that, by adding a boundary to the MERA, an accurate approximation to the ground state of a semi-infinite critical chain with an open boundary is obtained, from which one can extract boundary scaling operators and their scaling dimensions. As in Wilson's renormalization-group formulation of the Kondo problem, our construction produces, as a side result, an effective chain displaying explicit separation of energy scales. We present benchmark results for the quantum Ising and quantum XX models with free and fixed boundary conditions.

Evenbly, G.; Pfeifer, R. N. C.; Tagliacozzo, L.; McCulloch, I. P.; Vidal, G. [School of Physical Sciences, University of Queensland, Queensland 4072 (Australia); Pico, V.; Iblisdir, S. [Depto. Estructura i Constituents de la Materia, Universitat Barcelona, 08028 Barcelona (Spain)

2010-10-15

212

Atmospheric electricity  

NASA Technical Reports Server (NTRS)

In the last three years the focus was on the information contained in the lightning measurement, which is independent of other meteorological measurements that can be made from space. The characteristics of lightning activity in mesoscale convective systems were quantified. A strong relationship was found between lightning activity and surface rainfall. It is shown that lightning provides a precursor signature for wet microbursts (the strong downdrafts that produce windshears hazardous to aircraft) and that the lightning signature is a direct consequence of storm evolution. The Universities Space Research Association (USRA) collaborated with NASA scientists in the preliminary analysis and scientific justification for the design and deployment of an optical instrument which can detect lightning from geostationary orbit. Science proposals for the NASA mesoscale science program and for the Tethered Satellite System were reviewed. The weather forecasting research and unmanned space vehicles. Software was written to ingest and analyze the lightning ground strike data on the MSFC McIDAS system. The capabilities which were developed have a wide application to a number of problems associated with the operational impacts of electrical discharge within the atmosphere.

1987-01-01

213

Flavor singlet phenomena in lattice QCD  

E-print Network

Flavor singlet combinations of quark operators ${\\cal{O}}_S^{\\Gamma} = \\bar{u}\\Gamma u + \\bar{d}\\Gamma d + \\bar{s}\\Gamma s$ contribute to many important physical observables in the low energy region of QCD. Experimentally one finds the values of some of these observables to be in sharp contrast to the naive (perturbative) theoretical expectations. This indicates that non perturbative vacuum properties might play a major role in the comprehension of these phenomena. An example of such a vacuum contribution is the axial anomaly, which appears in the divergence of the flavor singlet axial current and which is connected to the topological properties of QCD. From a field theoretical point of view flavor singlet matrix elements differ from non singlet amplitudes in the occurrence of so called disconnected insertions. These are correlations of hadron propagators with quark-antiquark loops or correlations between quark-antiquark loops, which are mediated by vacuum fluctuations. According to their respective flavor composition, the disconnected insertions cancel largely in non singlet processes, but add in flavor singlet amplitudes. The lattice approach provides an ideal tool to study flavor singlet phenomena. Being a first principle method it should be capable to uncover non perturbative vacuum contributions and to yield, on the long run, reliable results for the size of such contributions in QCD. The present article reviews the status of flavor singlet matrix element calculations in lattice QCD with respect to methods, results and reliability. Special emphasis is paid to the discussion of state of the art calculations of the pion nucleon sigma term $\\sigma_{\\pi N}$, the flavor singlet axial coupling of the proton $G_A^1$, and the $\\eta'$ mass.

S. Güsken

1999-06-28

214

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

215

Airborne optic and magnetic observatory (ABOMO) for the investigation of the ionosphere, magnetosphere, and atmospheric proceses  

NASA Astrophysics Data System (ADS)

The St. Petersburg Filial (Division) of IZMIRAN has recently initiated a major new research project involving the Airborne Optic and Magnetic Observatory (ABOMO). ABOMO is designed specifically for studies of auroral, magnetic, ionospheric and atmospheric phenomena including ozone and other important atmospheric constituents. The observatory is constructed aboard a modified four-engine turboprop aircraft AN-12.

Raspopov, Oleg M.; Pochtarev, V. I.; Domaratskij, Serguej N.

1993-11-01

216

Jupiter Atmospheric Science in the Next Decade  

NASA Astrophysics Data System (ADS)

The exploration of Jupiter has played a pivotal role in the development of our understanding of the history of our solar system; it has served as a paradigm for the interpretation of exoplanetary systems around other stars, and as a fundamental laboratory for the myriad of physiochemical phenomena evident on the gas giants. Yet, despite great successes in the studies of Jupiter over four centuries of research, our characterisation of Jupiter remains incomplete. Jupiter's atmosphere is distinguished from Saturn's and the Ice Giants by its larger mass, dynamic "weather layer", multiple long-lived vortices and the smaller significance of seasonal variability. We review the scientific goals for Jovian exploration in the coming decade: 1. The bulk composition (e.g. heavy elements, isotopes), cooling history and internal structure (the existence of a core) of Jupiter as signatures of planetary formation and evolutionary models, along with comparisons to the other gas giants. 2. The development of a global three-dimensional understanding of the structure, meteorology and chemistry of the troposphere, stratosphere and mesosphere; the mechanisms for transport of energy, momentum and chemical species (tracers) vertically and horizontally, and the role of moist convection. 3. The coupling of the deep motions within the interior to the dynamical manifestations observed in the visible cloud layers. 4. Interactions between the lower neutral atmosphere and the upper atmosphere (thermosphere, ionosphere, magnetosphere), along with energy sources and redistribution responsible for aurora, radiolytic chemistry and high thermospheric temperatures. 5. Time-variable phenomena over a range of timescales to determine the underlying mechanisms and significance of the evolution of discrete atmospheric features, quasi-periodic global upheavals, energetic particle precipitation, asteroidal/cometary impacts and wave activity. These themes for Jupiter science will reveal the connections between deep interior, atmospheric weather layer and charged upper atmosphere; and constrain the origin and subsequent evolution of the gas giant.

Fletcher, Leigh N.; Orton, G.; Stallard, T.; Baines, K.; Sayanagi, K. M.; Martin-Torres, F. J.; Hofstadter, M.; de Pater, I.; Edgington, S.; Morales-Juberias, R.; Livengood, T.; Huestis, D.; Marty, B.; Hartogh, P.; Atkinson, D.; Moses, J.

2009-09-01

217

The Role of Family Phenomena in Posttraumatic Stress in Youth  

PubMed Central

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

Deatrick, Janet A.

2010-01-01

218

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

219

Living matter: the "lunar eclipse" phenomena.  

PubMed

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

Korpan, Nikolai N

2010-01-01

220

Phantom black holes and critical phenomena  

NASA Astrophysics Data System (ADS)

We consider the two classes cosh and sinh of normal and phantom black holes of Einstein-Maxwell-dilaton theory. The thermodynamics of these holes is characterized by heat capacities that may have both signs depending on the parameters of the theory. Leaving aside the normal Reissner-Nordström black hole, it is shown that only some phantom black holes of both classes exhibit critical phenomena. The two classes share a nonextremality, but special, critical point where the transition is continuous and the heat capacity, at constant charge, changes sign with an infinite discontinuity. This point yields a classification scheme for critical points. It is concluded that the two unstable and stable phases coexist on one side of the criticality state and disappear on the other side, that is, there is no configuration where only one phase exists. The sinh class has an extremality critical point where the entropy diverges. The transition from extremality to nonextremality with the charge held constant is accompanied by a loss of mass and an increase in the temperature. A special case of this transition is when the hole is isolated (microcanonical ensemble), it will evolve by emission of energy, which results in a decrease of its mass, to the final state of minimum mass and vanishing heat capacity. The Ehrenfest scheme of classification is inaccurate in this case but the generalized one due to Hilfer leads to conclude that the transition is of order less than unity. Fluctuations near criticality are also investigated.

Azreg-Aïnou, Mustapha; Marques, Glauber T.; Rodrigues, Manuel E.

2014-07-01

221

Numerical simulation of hot-electron phenomena  

SciTech Connect

An accurate two-dimensional numerical model for MOS transistors incorporating avalanche processes is presented. The Laplace and Poisson equations for the electrostatic potential in the gate oxide and bulk and the current-continuity equations for the electron and hole densities are solved using finite-difference techniques. The current-continuity equations incorporate terms modeling avalanche generation, bulk and surface Shockley-Read-Hall thermal generation-recombination, and Auger recombination processes. The simulation is performed to a depth in the substrate sufficient to include the depletion region, and the remaining substrate is modeled as a parasitic resistance. The increase in the substrate potential caused by the substrate current flowing through the substrate resistance is also included. The hot-electon distribution function is modeled using Baraff's maximum anisotropy distribution function. The model is used to study hot-electron phenomena including negative-resistance avalanche breakdown in short-channel MOSFET's and electron injection into the gate oxide. The model accurately predicts the positive-resistance branch of the drain current-voltage characteristic and could, in principle, predict the negative-resistance branch and the sustain voltage.

Watanabe, D.S.; Slamet, S.

1983-09-01

222

Genome imprinting phenomena on mouse chromosome 7.  

PubMed

Heterozygotes for the reciprocal translocation T(7;15)9H were intercrossed, with albino (c) and underwhite (uw) as genetic markers, in order to study genetic complementation in mouse chromosome 7. Chromosome 15 is known to show normal complementation. Neither reciprocal cross in which one parent was c/c and the other wild type yielded albino progeny at birth although about 17% would be expected, but albino foetuses were recovered when the mother was c/c and father wild type. These products of maternal duplication/paternal deficiency for distal 7 were markedly retarded with small placentae. No albino foetuses were found when the father was c/c and mother wild type, which suggested earlier lethality. Equivalent crosses with uw (chromosome 15) as proximal marker gave normal underwhite progeny when the mother was uw/uw but small placentae, retardation and neonatal death of presumptive underwhites in the reciprocal cross. These abnormal newborn would have had a maternal duplication/paternal deficiency for proximal 7. These and other findings indicate that one region of defective complementation probably lies distal to the breakpoint of T(7;18)50H at 7E2-F2, while another is between the centromere and 7B3. Examination of man-mouse homologies suggests that the loci for three pathological human conditions (Beckwith-Weidemann syndrome, dystrophia myotonia and rhabdomyosarcoma) with differential parental transmission may be located in homologous regions to those affected by imprinting phenomena on mouse chromosome 7. PMID:2272514

Searle, A G; Beechey, C V

1990-01-01

223

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

224

Further shock tunnel studies of scramjet phenomena  

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

225

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

NASA Technical Reports Server (NTRS)

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

1984-01-01

226

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

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

227

Effect of resonance phenomena on the wave structure of the middle atmosphere  

NASA Astrophysics Data System (ADS)

Based on data of the optical measurements performed at Orbita observatory, Almaty (76°55' E, 43°15' N), it has been established that the region of LF oscillations in the range of periods from 0.5 to 2.5 h includes the components composed of the heterodyne frequencies of two oscillations. It has been indicated that the origination of these harmonics can be interpreted when solving the linear problem of a resonance behavior of acoustic gravity waves under the action of diurnal variations in the solar radiation intensity, and the heterodyne frequencies appear due to the effect of acoustic gravity wave enhancement in an acoustically active medium.

Suleimenov, I. E.; Aushev, V. M.; Tulebekov, E. A.; Antoshchuk, I. A.

2006-05-01

228

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

NASA Technical Reports Server (NTRS)

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

Bertani, A.

1982-01-01

229

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.

230

The earth's atmosphere.  

NASA Technical Reports Server (NTRS)

Topics discussed include the effects of solar radiation on the heat balance of the earth and its atmosphere, the physicomathematical models of the atmosphere and the computational schemes used in numerical investigations of the general circulation of the atmosphere, the effects of atmospheric turbulence on aeronautical systems, te chemistry of different regions of the atmosphere, the use of hot-filament and cold-cathode vacuum gauges to measure upper-atmosphere densities, methods of determining the air density at heights near a satellite's perigee by analyzing changes in its orbit, and an evaluation of various atmospheric models in the 100- to 1000-km altitude range.

Vaughan, W. W. (editor); Devries, L. L.

1972-01-01

231

Investigation of collective phenomena in dusty plasmas  

NASA Astrophysics Data System (ADS)

I study dusty plasma produced by electrostatically confining melamine formaldehyde microparticles in a radio-frequency glow discharge plasma. Dusty plasma is a mixture of particles of solid matter (dust), electrons, ions, and neutral gas atoms. The dust particles have a very high charge and a mass compared to the electrons and ions in the ambient plasma. As a consequence, a dusty plasma exhibits collective phenomena such as dust acoustic waves, crystallization, and melting. The discrete nature of dust particles gives rise to compressibility. In this thesis I report findings of four tasks that were performed to investigate dust acoustic waves, compressibility, and melting. First, the nonlinear phenomenon of synchronization was characterized experimentally for the dust acoustic wave propagating in a dust cloud with many layers. I find four synchronized states, with frequencies that are multiples of 1, 2, 3, and 1/2 of the driving frequency. Comparing to phenomena that are typical of the van der Pol paradigm, I find that synchronization of the dust acoustic wave exhibits the signature of the suppression mechanism but not that of the phaselocking mechanism. Additionally, I find that the synchronization of the dust acoustic wave exhibits three characteristics that differ from the van der Pol paradigm: a threshold amplitude that can be seen in the Arnold tongue diagram, a branching of the 1:1 harmonic tongue at its lower extremity, and a nonharmonic state. Second, to assess which physical processes are important for a dust acoustic instability, I derived dispersion relations that encompass more physical processes than commonly done. I investigated how various physical processes affect a dust acoustic wave by solving these dispersion relations using parameters from a typical dust acoustic wave experiment. I find that the growth rate diminishes for large ion currents. I also find that the compressibility, a measure of the coupling between the dust particles, have a strong effect on the wave propagation. Comparing the kinetic vs. hydrodynamic descriptions for ions, I find that under typical laboratory conditions the inverse Landau damping and the ion-neutral collisions contribute about equally to the dust acoustic instability. Third, I performed dust acoustic wave experiments to resolve a previously unremarked discrepancy in the literature regarding the sign of the compressibility of a strongly-coupled dust component in a dusty plasma. According to theories compressibility is negative, whereas experiments suggest that it is positive. I find that the compressibility is positive. This conclusion was reached after allowing for a wide range of experimental uncertainties and model dependent systematic errors. Finally, the polygon construction method of Glaser and Clark was used to characterize crystallization and melting in a single-layer dusty plasma. Using particle positions measured in a previous dusty plasma experiment, I identified geometrical defects, which are polygons with four or more sides. These geometrical defects are found to proliferate during melting. I also identify a possibility of latent heat involvement in melting and crystallization processes of a dusty plasma.

Ruhunusiri, Wellalage Don Suranga

232

Magnetoacoustic Phenomena in Saturated Porous Media  

NASA Astrophysics Data System (ADS)

This work deals with dynamic interaction between electromagnetic and hydrodynamic types of motions in a porous medium, saturated with electrolyte. The system of equations is a coupling of equations of the two-velocity continuous filtration theory and Maxwell equations in quasi-stationary approximation. The method of separation by the physical processes is used for numerical solution, and the hyperbolic system is approximated by the explicit expanded Godunov scheme, and the parabolic system is approximated by the inexplicit Crank-Nicolson scheme. Generation of the magnetic field was modeled in the process of 2D electrolyte filtration in a porous medium, which is considered to be conducing because of a double electric layer. An entrainment in the external magnetic field over the electrolyte flow into a porous medium is observed, and the location of magnetic field maximum relative to the inlet boundary is determined by the ratio of kinematic viscosity to magnetic viscosity. A rise of this ratio provides more intensive drag of a filtered liquid and increasing magnetic field, reached in a porous medium. Downward the flow the field decreases because of magnetic field diffusion. The problem with simultaneous excitation of acoustic and electromagnetic perturbations at the boundary of saturated porous medium was also considered, and this allows us to obtain additional knowledge about accompanying effects and phenomena, what is the main scientific and practical goal of geophysics and oil survey. This research was supported by the Russian Foundation for Basic Research grant 06-05-65110, by the President's grants NSh-1573.2003.5, and by the Russian Ministry Science and Education grant RNP.2.1.1.702.

Perepechko, Y.

2007-12-01

233

POSTTHYMECTOMY WASTING ASSOCIATED WITH AUTOIMMUNE PHENOMENA  

PubMed Central

1. Mice of A and C57BL/6 Ks strains, thymectomized at birth acquire wasting disease in 84.1% (A) and 77.1% (C57BL/6 Ks) of the cases. There is no sex predelection. 2. Anemia in these animals is characterized by shortened red cell survival and increased fragility to hypotonic salt solutions. Among thymectomized A mice reticulocytosis is absent and extramedullary hematopoiesis is found in the spleen in the presence of bone marrow hypoplasia for the erythroid and lymphocyte series. 3. Positive antiglobulin tests of the red cells were observed in all the thymectomized C57BL/6 Ks (7/7) and 71.2% of the A strains (62/87). Normal mice do not show positive Coombs' tests. 4. The globulin coat on the A strain consists of IgM, whereas ?1C and IgG are not detectable. By contrast, red cell coats of NZB mice developing spontaneous autoimmune hemolytic anemia show IgM and ?1C, but these erythrocytes do not react with anti-gamma chain antibodies. Another difference in the globulin coats of the two types of erythrocytes is that the IgM on NZB red cells has available light chain determinants but these are apparently hidden or absent in the case of sensitized erythrocytes. The difference in antibody coating, association with a component of complement in one but not the other, suggests a different mechanism for the immune surface phenomenon in each instance. 5. Anemia in NZB mice is associated with reticulocytosis while that in thymectomized A mice is not. 6. Thymectomy appears to initiate a chain of events leading to a series of autoimmune phenomena which may be due to alteration in host response consequent to loss of thymic tissue and thymic dependent functions or alternatively to infection to which increased susceptibility exists as a result of thymic extirpation. PMID:4164823

Yunis, Edmond J.; Hong, Richard; Grewe, Mary Alice; Martinez, Carlos; Cornelius, Eugene; Good, Robert A.

1967-01-01

234

CFD Analysis of Core Bypass Phenomena  

SciTech Connect

The U.S. Department of Energy is exploring the potential for the VHTR which will be either of a prismatic or a pebble-bed type. One important design consideration for the reactor core of a prismatic VHTR is coolant bypass flow which occurs in the interstitial regions between fuel blocks. Such gaps are an inherent presence in the reactor core because of tolerances in manufacturing the blocks and the inexact nature of their installation. Furthermore, the geometry of the graphite blocks changes over the lifetime of the reactor because of thermal expansion and irradiation damage. The existence of the gaps induces a flow bias in the fuel blocks and results in unexpected increase of maximum fuel temperature. Traditionally, simplified methods such as flow network calculations employing experimental correlations are used to estimate flow and temperature distributions in the core design. However, the distribution of temperature in the fuel pins and graphite blocks as well as coolant outlet temperatures are strongly coupled with the local heat generation rate within fuel blocks which is not uniformly distributed in the core. Hence, it is crucial to establish mechanistic based methods which can be applied to the reactor core thermal hydraulic design and safety analysis. Computational Fluid Dynamics (CFD) codes, which have a capability of local physics based simulation, are widely used in various industrial fields. This study investigates core bypass flow phenomena with the assistance of commercial CFD codes and establishes a baseline for evaluation methods. A one-twelfth sector of the hexagonal block surface is modeled and extruded down to whole core length of 10.704m. The computational domain is divided vertically with an upper reflector, a fuel section and a lower reflector. Each side of the one-twelfth grid can be set as a symmetry boundary

Richard W. Johnson; Hiroyuki Sato; Richard R. Schultz

2009-11-01

235

CFD Analysis of Core Bypass Phenomena  

SciTech Connect

The U.S. Department of Energy is exploring the potential for the VHTR which will be either of a prismatic or a pebble-bed type. One important design consideration for the reactor core of a prismatic VHTR is coolant bypass flow which occurs in the interstitial regions between fuel blocks. Such gaps are an inherent presence in the reactor core because of tolerances in manufacturing the blocks and the inexact nature of their installation. Furthermore, the geometry of the graphite blocks changes over the lifetime of the reactor because of thermal expansion and irradiation damage. The existence of the gaps induces a flow bias in the fuel blocks and results in unexpected increase of maximum fuel temperature. Traditionally, simplified methods such as flow network calculations employing experimental correlations are used to estimate flow and temperature distributions in the core design. However, the distribution of temperature in the fuel pins and graphite blocks as well as coolant outlet temperatures are strongly coupled with the local heat generation rate within fuel blocks which is not uniformly distributed in the core. Hence, it is crucial to establish mechanistic based methods which can be applied to the reactor core thermal hydraulic design and safety analysis. Computational Fluid Dynamics (CFD) codes, which have a capability of local physics based simulation, are widely used in various industrial fields. This study investigates core bypass flow phenomena with the assistance of commercial CFD codes and establishes a baseline for evaluation methods. A one-twelfth sector of the hexagonal block surface is modeled and extruded down to whole core length of 10.704m. The computational domain is divided vertically with an upper reflector, a fuel section and a lower reflector. Each side of the sector grid can be set as a symmetry boundary

Richard W. Johnson; Hiroyuki Sato; Richard R. Schultz

2010-03-01

236

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

237

Individualization of the anisotropic phenomena of the imbalanced Nature  

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

238

Pendulum Phenomena and the Assessment of Scientific Inquiry Capabilities  

ERIC Educational Resources Information Center

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…

Zachos, Paul

2004-01-01

239

FOREST FIRES AND OIL FIELDS AS PERCOLATION PHENOMENA.  

E-print Network

FOREST FIRES AND OIL FIELDS AS PERCOLATION PHENOMENA. William J. Reed #3; JUNE, 1999. Abstract A probability distribution derived from percolation theory is #12;tted to large datasets on the sizes of forest forest #12;res and oil #12;elds as percolation phenomena as well as suggesting the consideration of a new

Reed, W.J.

240

Geometric treatment of electromagnetic phenomena in conducting materials: variational principles  

E-print Network

Geometric treatment of electromagnetic phenomena in conducting materials: variational principles@unizar.es, carlos.lopez@uah.es Abstract. The dynamical equations of an electromagnetic field coupled.20.De To be published: J. Phys. A: Math. Gen. #12;Geometric treatment of electromagnetic phenomena 2 1

Majós, Antonio Badía

241

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

242

Magnetoresistive phenomena in nanoscale magnetic systems  

NASA Astrophysics Data System (ADS)

Nanomagnetic materials are playing an increasingly important role in modern technologies. A particular area of interest involves the interplay between magnetism and electric transport, i.e. magnetoresistive properties. Future generations of field sensors and memory elements will have to be on a length scale of a few nanometers or smaller. Magnetoresistive properties of such nanoscale objects exhibit novel features due to reduced dimensionality, complex surfaces and interfaces, and quantum effects. In this dissertation theoretical aspects of three such nanoscale magnetoresistive phenomena are discussed. Very narrow magnetic domain walls can strongly scatter electrons leading to an increased resistance. Specifically, this dissertation will cover the newly predicted effect of magnetic moment softening in magnetic nanocontacts or nanowires. Atomically thin domain walls in Ni exhibit a reduction, or softening, of the local magnetic moments due to the noncollinearity of the magnetization. This effect leads to a strong enhancement of the resistance of a domain wall. Magnetic tunnel junctions (MTJs) consist of two ferromagnetic electrodes separated by a thin layer of insulating material through which current can be carried by electron tunneling. The resistance of an MTJ depends on the relative orientation of the magnetization of the two ferromagnetic layers, an effect known as tunneling magnetoresistance (TMR). A first-principles analysis of CoFeB|MgO|CoFeB MTJs will be presented. Calculations reveal that it is energetically favorable for interstitial boron atoms to reside at the interface between the electrode and MgO tunneling barrier, which can be detrimental to the TMR effect. Anisotropic magnetoresistance (AMR) is the change in resistance of a ferromagnetic system as the orientation of the magnetization is altered. In this dissertation, the focus will be on AMR in the tunneling regime. Specifically we will present new theoretical results on tunneling AMR (TAMR) in two systems: (i) planar MTJs with CoFe electrodes and (ii) fully broken magnetic break junctions. In both cases electronic resonances in the electrodes lead to complex angular and bias dependence of the TAMR. The theoretical studies demonstrate the basic physical phenomenon behind recent experimental data.

Burton, John D.

243

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

244

Nonlinear electrokinetic phenomena in microfluidic devices  

NASA Astrophysics Data System (ADS)

This thesis addresses nonlinear electrokinetic mechanisms for transporting fluid and particles in microfluidic devices for potential applications in biomedical chips, microelectronic cooling and micro-fuel cells. Nonlinear electrokinetics have many advantages, such as low voltage, low power, high velocity, and no significant gas formation in the electrolyte. However, they involve new and complex charging and flow mechanisms that are still not fully understood or explored. Linear electrokinetic fingering that occurs when a fluid with a lower electrolyte concentration advances into one with a higher concentration is first analyzed. Unlike earlier miscible fingering theories, the linear stability analysis is carried out in the self-similar coordinates of the diffusing front. This new spectral theory is developed for small-amplitude gravity and viscous miscible fingering phenomena in general and applied to electrokinetic miscible fingering specifically. Transient electrokinetic fingering is shown to be insignificant in sub-millimeter micro-devices. Nonlinear electroosmotic flow around an ion-exchange spherical granule is studied next. When an electric field is applied across a conducting and ion-selective porous granule in an electrolyte solution, a polarized surface layer with excess counter-ions is created. The flux-induced polarization produces a nonlinear slip velocity to produce micro-vortices around this sphere. This polarization layer is reduced by convection at high velocity. Two velocity scalings at low and high electric fields are derived and favorably compared with experimental results. A mixing device based on this mechanism is shown to produce mixing efficiency 10-100 times higher than molecular diffusion. Finally, AC nonlinear electrokinetic flow on planar electrodes is studied. Two double layer charging mechanisms are responsible for the flow---one due to capacitive charging of ions from the bulk electrolyte and one due to Faradaic reactions at the electrode that consume or produce ions in the double layer. Faradaic charging is analyzed for specific reactions. From the theory, particular electrokinetic flows above the electrodes are selected for micropumps and bioparticle trapping by specifying the electrode geometry and the applied voltage and frequency.

Ben, Yuxing

245

Coherence Related Gain Phenomena in Potassium -  

NASA Astrophysics Data System (ADS)

This work focuses on the theoretical and experimental investigations of coherence related gain phenomena in a collisionally assisted, four-level Raman-driven system, where atomic collisions provide incoherent population to the probed excited state. The theory, as originally envisioned by Narducci and coworkers(1) (without collisions), is first introduced and discussed. Modifications to this theory are made to allow for the addition of atomic collision processes, including dephasing, incoherent transfer of excited state population, and transit relaxation. The modified theory is then applied to a model system simulating a potassium-(noble gas) mixture. Examination of this model reveals several features, including: (1) inversionless amplification of a probe beam is possible; (2) helium is the best choice of buffer gas to facilitate the collisional transfer of excited state population, while at the same time minimizing the undesirable relaxation of coherences due to dephasing; and (3) a copropagating pump/probe geometry is best for optimum results. In addition, it is found that many of these theoretical results can also be found in a three-level V configuration with collisional transfer used to populate the probed excited state. Time-dependent and time-independent methods of distinguishing between the two theoretical systems are discussed. The experimental realization of this system in potassium-helium and potassium-argon mixtures, with strong laser pumping and weak probing on the potassium D lines, shows good agreement with the Block equation theoretical analysis of a four-level model using realistic atomic parameters. Gain and altered absorption profiles are observed and compare well with theory. The experimental gain behavior with respect to pump power supports the four-level model over the three-level model. The experiments are insensitive to relative pump/probe linear polarizations. Measurements of atomic energy level populations for a strongly driven 14.2 torr helium-potassium mixture, demonstrating gain for line center pumping, are conducted and discussed. The measured relative populations for this case are: n(4P _{1/2})/n_{ rm total} =.0982 +/-.034; and n(4P_{3/2})/n _{rm total} =.193 +/-.083. These measurements imply that the probed level 4P_{1/2} population is not inverted with respect to the ground state. ftn(1) L. M. Narducci, H. M. Doss, P. Ru, M. O. Scully, S. Y. Zhu, and C. Keitel, Opt. Commun. 81, 379 (1991).

Kleinfeld, Jeffrey A.

1995-01-01

246

Karstic Phenomena Susceptibility Map of MÉXICO  

NASA Astrophysics Data System (ADS)

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

Espinasa-Pereña, R.

2013-05-01

247

Conceptual Framework to Enable Early Warning of Relevant Phenomena (Emerging Phenomena and Big Data)  

SciTech Connect

Graphs are commonly used to represent natural and man-made dynamic systems such as food webs, economic and social networks, gene regulation, and the internet. We describe a conceptual framework to enable early warning of relevant phenomena that is based on an artificial time-based, evolving network graph that can give rise to one or more recognizable structures. We propose to quantify the dynamics using the method of delays through Takens Theorem to produce another graph we call the Phase Graph. The Phase Graph enables us to quantify changes of the system that form a topology in phase space. Our proposed method is unique because it is based on dynamic system analysis that incorporates Takens Theorem, Graph Theory, and Franzosi-Pettini (F-P) theorem about topology and phase transitions. The F-P Theorem states that the necessary condition for phase transition is a change in the topology. By detecting a change in the topology that we represent as a set of M-order Phase Graphs, we conclude a corresponding change in the phase of the system. The onset of this phase change enables early warning of emerging relevant phenomena.

Schlicher, Bob G [ORNL] [ORNL; Abercrombie, Robert K [ORNL] [ORNL; Hively, Lee M [ORNL] [ORNL

2013-01-01

248

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

249

Atmospheric Science Experiment for Mars: ATMIS for the Netlander 2005 Mission  

NASA Technical Reports Server (NTRS)

ATMIS (Atmospheric and Meteorological Instrumentation System) is a versatile suite of atmospheric instrumentation to be accommodated onboard the Netlander Mission slated for launch in 2005. Four Netlanders are planned to form a geophysical measurement network on the surface of Mars. The atmospheric sciences are among the scientific disciplines benefiting most of the network concept. The goal of the ATMIS instrument is to provide new data on the atmospheric vertical structure, regional and global circulation phenomena, the Martian Planetary Boundary Layer (PBL) and atmosphere-surface interactions, dust storm triggering mechanisms, as well as the climatological cycles of H2O, dust and CO2. To reach the goal of characterization of a number of phenomena exhibiting both spatial and temporal variations, simultaneous observations of multiple variables at spatially displaced sites Deforming a network D are required. The in situ observations made by the ATMIS sensors will be supported by extensive modeling efforts. Additional information is contained in the original extended abstract.

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

1999-01-01

250

ldentifying Episodes of Earth Science Phenomena Using a Big-Data Technology  

NASA Technical Reports Server (NTRS)

A significant portion of Earth Science investigations is phenomenon- (or event-) based, such as the studies of Rossby waves, volcano eruptions, tsunamis, mesoscale convective systems, and tropical cyclones. However, except for a few high-impact phenomena, e.g. tropical cyclones, comprehensive records are absent for the occurrences or events of these phenomena. Phenomenon-based studies therefore often focus on a few prominent cases while the lesser ones are overlooked. Without an automated means to gather the events, comprehensive investigation of a phenomenon is at least time-consuming if not impossible. We have constructed a prototype Automated Event Service (AES) system that is used to methodically mine custom-defined events in the reanalysis data sets of atmospheric general circulation models. Our AES will enable researchers to specify their custom, numeric event criteria using a user-friendly web interface to search the reanalysis data sets. Moreover, we have included a social component to enable dynamic formation of collaboration groups for researchers to cooperate on event definitions of common interest and for the analysis of these events. An Earth Science event (ES event) is defined here as an episode of an Earth Science phenomenon (ES phenomenon). A cumulus cloud, a thunderstorm shower, a rogue wave, a tornado, an earthquake, a tsunami, a hurricane, or an El Nino, is each an episode of a named ES phenomenon, and, from the small and insignificant to the large and potent, all are examples of ES events. An ES event has a duration (often finite) and an associated geo-location as a function of time; it's therefore an entity embedded in four-dimensional (4D) spatiotemporal space. Earth Science phenomena with the potential to cause massive economic disruption or loss of life often rivet the attention of researchers. But, broader scientific curiosity also drives the study of phenomena that pose no immediate danger, such as land/sea breezes. Due to Earth System's intricate dynamics, we are continuously discovering novel ES phenomena. We generally gain understanding of a given phenomenon by observing and studying individual events. This process usually begins by identifying the occurrences of these events. Once representative events are identified or found, we must locate associated observed or simulated data prior to commencing analysis and concerted studies of the phenomenon. Knowledge concerning the phenomenon can accumulate only after analysis has started. However, as mentioned previously, comprehensive records only exist for a very limited set of high-impact phenomena; aside from these, finding events and locating associated data currently may take a prohibitive amount of time and effort on the part of an individual investigator. The reason for the lack of comprehensive records for most of the ES phenomena is mainly due to the perception that they do not pose immediate and/or severe threat to life and property. Thus they are not consistently tracked, monitored, and catalogued. Many phenomena even lack precise and/or commonly accepted criteria for definitions. Moreover, various Earth Science observations and data have accumulated to a previously unfathomable volume; NASA Earth Observing System Data Information System (EOSDIS) alone archives several petabytes (PB) of satellite remote sensing data, which are steadily increasing. All of these factors contribute to the difficulty of methodically identifying events corresponding to a given phenomenon and significantly impede systematic investigations. We have not only envisioned AES as an environment for identifying customdefined events but also aspired for it to be an interactive environment with quick turnaround time for revisions of query criteria and results, as well as a collaborative environment where geographically distributed experts may work together on the same phenomena. A Big Data technology is thus required for the realization of such a system. In the following, we first introduce the technology selected for AES in the next section. We then demonstrate the uti

Kuo, Kwo-Sen; Oloso, Amidu; Rushing, John; Lin, Amy; Fekete, Gyorgy; Ramachandran, Rahul; Clune, Thomas; Dunny, Daniel

2014-01-01

251

Low energy electron collision parameters for modeling auroral/dayglow phenomena  

NASA Astrophysics Data System (ADS)

From the tenuous atmospheres of Pluto and Triton to the higher pressure atmospheres of Earth and Titan, electron-collisions with molecular nitrogen continue to warrant attention. The airglow emissions of N2 from the atmospheres of Earth and planetary satellites have been extensively observed. Accurate, consistent cross section data is a necessity for accurate models of how upper atmospheres behave. This enables determinations of solar energy inputs and atmospheric expansion and contraction, which influences satellite orbits for instance. Recent work by Lean et al. [1], Stevens et al. [2], and Kato et al. [3] appear to substantiate our e^-+N2 excitation and emission work (e.g., Johnson et al. [4], Malone et al. [5], Young et al. [6] and references therein). Recently, we have focused on the near-threshold-to-peak region of N2 with the goal of providing low energy collision parameters of the X^1?g^+(0)--A^3?u^+, B^3?g, W^3?u, B^'3?u^-, a^'1?u^-, a^1?g, w^1?u, C^3?u, and E^3?g^+ transitions for modeling auroral and dayglow phenomena in these N2-rich atmospheres. The Lyman-Birge-Hopfield (LBH) emissions, from a^1?g(v^')--X^1?g^+(v^'') transitions, are `bellwether' measurements for diurnal Terrestrial Space Weather variations [7]. However, near-threshold cross section data is still lacking for the a^1?g state, as well as the `slow-cascade' a^'1?u^- and w^1?u contributors to LBH emissions. In addition, Vegard-Kaplan (VK) emissions, from the A^3?u^+(v^')--X^1?g^+(v^'') transitions, recently observed in Titan's thermosphere [2], require further improved monoenergetic laboratory measurements. New electron energy-loss measurements, along with direct excitation (integral) cross sections, are presented for excitation of the lower states of N2, with finely-spaced impact energy increments in the threshold-to-peak region. Our recent work, including vibrationally resolved excitation, addresses these atmospheric data needs.[4pt] [1] Lean et al., 2011, JGR, 116, A01102. ,[4] Johnson et al., 2005, JGR, 110, A11311. [2] Stevens et al., 2011, JGR, 116, A05304. [5] Malone et al., 2009, J. Phys. B, 42, 135201. [3] Kato et al., 2010, PRA, 81, 042717. ;;, [6] Young et al., 2010, J. Phys. B, 43, 135201. [7] Ajello et al., 2011, UV Molecular Spectroscopy from Electron Impact for Applications to Planetary Atmospheres and Astrophysics, Book Chapter 28, published in ``Charged Particle and Photon Interactions with Matter'' Recent Advances, Applications, and Interfaces-Eds., Hatano et al., Taylor & Francis, Boca Raton, FL.

Malone, Charles P.

2011-11-01

252

Synchro-ballistic recording of detonation phenomena  

SciTech Connect

Synchro-ballistic use of rotating-mirror streak cameras allows for detailed recording of high-speed events of known velocity and direction. After an introduction to the synchro-ballistic technique, this paper details two diverse applications of the technique as applied in the field of high-explosives research. In the first series of experiments detonation-front shape is recorded as the arriving detonation shock wave tilts an obliquely mounted mirror, causing reflected light to be deflected from the imaging lens. These tests were conducted for the purpose of calibrating and confirming the asymptotic Detonation Shock Dynamics (DSD) theory of Bdzil and Stewart. The phase velocities of the events range from ten to thirty millimeters per microsecond. Optical magnification is set for optimal use of the film`s spatial dimension and the phase velocity is adjusted to provide synchronization at the camera`s maximum writing speed. Initial calibration of the technique is undertaken using a cylindrical HE geometry over a range of charge diameters and of sufficient length-to-diameter ratio to insure a stable detonation wave. The final experiment utilizes an arc-shaped explosive charge, resulting in an asymmetric detonation-front record. The second series of experiments consists of photographing a shaped-charge jet having a velocity range of two to nine millimeters per microsecond. To accommodate the range of velocities it is necessary to fire several tests, each synchronized to a different section of the jet. The experimental apparatus consists of a vacuum chamber to preclude atmospheric ablation of the jet tip with shocked-argon back lighting to produce a shadow-graph image.

Critchfield, R.R.; Asay, B.W.; Bdzil, J.B.; Davis, W.C.; Ferm, E.N.; Idar, D.J.

1997-09-01

253

Certain relativistic phenomena in crystal optics  

NASA Astrophysics Data System (ADS)

Relativistic unsteady phenomena are established for a crystalline medium with unaligned sets of permittivity and permeability principal axes, but incorporating a compounded uniaxiality about some nonprincipal direction. All effects originate from a suddenly activated, arbitrarily oriented, maintained line current conducted with a finite velocity v. Integral representations studied in another paper (Chee-Seng) are applied. The original coordinate system is subjected to a series of rotational and translational, scaled and unscaled transformations. No specific coordinate frame is strictly adhered to. Instead, it is often expedient and advantageous to exploit several reference frames simultaneously in the course of the analysis and interpretations. The electric field is directly related to a net scalar field ? involving another scalar ? and its complement ?¯ which can be deduced from ?; ? and ?¯ are associated with two expanding, inclined ellipsoidal wavefronts ? and ?¯; these are cocentered at the current origin and touch each other twice along the uniaxis. Elsewhere, ? leads ?¯. For a source current faster than ?:vt ? ext?, ??0 within a finite but growing ''ice-cream cone'' domain, its nontrivial composition being ?-1/2 inside ? and 2?-1/2 inside part of a tangent cone from the advancing current edge vt to, and terminating at, ?; the function ? vanishes along such a tangent cone. Alternatively, for a source current slower than ?:vt? int?, if vt is avoided, ??0 everywhere, while ?=?-1/2 inside ? but vanishes identically outside ?. However, the crucial scalar field ? depends on three separate current-velocity regimes. Over a slow regime: vt? int?¯, ? is nontrivial inside ? wherein it is discontinuous across ?¯. Over an intermediate regime: vt ? int? ext?¯, ? takes four distinct forms on 12 adjacent domains bounded by ?, ?¯ and a double-conical tangent surface linking vt to ?¯. But for a fast regime: vt? ext?, ? assumes six distinct forms on 18 adjacent domains bounded by ?, ?¯ plus two double-conical tangent surfaces, convertexed at vt, to both ? and ?¯. Singularities are normally confined to these boundaries. Relative to a moving frame, ? is time-independent. Nevertheless, ? and, consequently, ? evolve unsteadily, principally because of transitions across the expanding ellipsoids ? and ?¯ which also acquire a relative retreat from the current edge vt. An evolution scheme is discussed in detail. This produces, among other things, a steady state corollary which, in turn, covers ?erenkov radiation. A quadrical symmetry exists with respect to a family {Q?} of constant ?-surfaces. These are quadric surfaces cocentered at vt and having principal axes inclined to those of ? (and ?¯). Their interactions with ? are closely examined. If vt ? ext?, each Q? is a hyperboloid of two sheets which are asymptotic to the double-conical tangent surface connecting ? to vt; ? can become nontrivial on only one sheet, viz., that which is approached by ? as the latter retreats from vt; eventually, two permanent intersections, one following the other, occur along two expanding and travelling parallel plane circuits. But if vt ? int?, each Q? is an ellipsoid inside which ? initially evolves until an encounter occurs, first as a point contact which immediately grows into a plane circuit; as this traverses Q?, it expands and then contracts to a diametrically opposite point where contact breaks off. Finally, an elliptical axisymmetry about a principal direction of {Q?} is demonstrated. Corresponding behaviors hold in relation to ?¯.

Chee-Seng, Lim

1980-01-01

254

Analytical investigation of critical phenomena in MHD power generators  

NASA Technical Reports Server (NTRS)

Critical phenomena in the Arnold Engineering Development Center (AEDC) High Performance Demonstration Experiment (HPDE) and the U.S. U-25 Experiment, are analyzed. The performance of a NASA specified 500 MW(th) flow train is analyzed. Critical phenomena analyzed include: Hall voltage overshoots; optimal load schedules; parametric dependence of the electrode voltage drops; boundary layer behavior; near electrode phenomena with finite electrode segmentation; current distribution in the end regions; scale up rules; optimum Mach number distribution; and the effects of alternative cross sectional shapes.

1980-01-01

255

Stellar atmospheric structural patterns  

NASA Technical Reports Server (NTRS)

The thermodynamics of stellar atmospheres is discussed. Particular attention is given to the relation between theoretical modeling and empirical evidence. The characteristics of distinctive atmospheric regions and their radical structures are discussed.

Thomas, R. N.

1983-01-01

256

The atmosphere of Mars  

NASA Technical Reports Server (NTRS)

The atmosphere of Mars is essentially a pure carbon dioxide atmosphere that contains a small and seasonably varying amount of water vapor. A number of minor constituents which arise from the interactions of solar radiation with water vapor and carbon dioxide include carbon monoxide, atomic oxygen, molecular oxygen, ozone, and atomic hydrogen. At the surface of Mars the atmospheric pressure is less than one hundredth of the pressure at the surface of the earth. Extensive cloud systems appear on Mars. The structure of the lower Martian atmosphere is discussed together with variations in the lower atmosphere and the characteristics of the upper atmosphere. Reactions of photochemistry are considered along with the atmospheric escape and interactions between the atmosphere and the polar caps.

Barth, C. A.

1974-01-01

257

The Atmosphere of Venus  

NASA Technical Reports Server (NTRS)

Topics considered at the conference included the dynamics, structure, chemistry, and evolution of the Venus atmosphere, as well as cloud physics and motion. Infrared, ultraviolet, and radio occultation methods of analysis are discussed, and atmospheric models are described.

Hansen, J. E. (editor)

1975-01-01

258

Ionospheric VLF Waves and Optical Phenomena Over Active Thunderstorms.  

NASA Astrophysics Data System (ADS)

In 1987 and 1988, two campaigns, the Wave Induced Particle Precipitation campaign and the Thunderstorm II campaign, were conducted to investigate lightning-generated effects in the upper atmosphere and ionosphere. Two rockets (apogees 420km and 330km) and 6 balloons (float altitudes 30km) were launched near thunderstorms in these campaigns. Optical and electric signals from hundreds of lightning strokes were recorded by both the rockets and balloons. Using the data obtained in these two campaigns, we have been able to study some problems about lightning -generated VLF waves in the ionosphere which have not been well investigated previously. In this dissertation, we report the following: (1) The downward-looking optical detector on the rocket recorded some anomalous characteristic optical phenomena which had not been reported previously. Our study shows that they occurred above the balloon altitude (30km), and we interpreted the results in terms of discharges at high altitudes. (2) We studied the relation between the amplitude of lightning-generated VLF waves in the ionosphere and the lightning current recorded by the SUNYA lightning network. Our study shows that the amplitude of waves at frequencies below 5 kHz has linear response to the lightning current. Above 5 kHz, there is not a significant linear correlation between the wave amplitude and the lightning current. (3) We have been able to determine the propagation path of the lightning-generated VLF waves from the source to the rocket. The path is consistent with the leaky waveguide hypothesis in which waves travel in the waveguide to the vicinity of the rockets, and then propagate vertically through the ionosphere. (4) We have found that the amplitude of lightning-generated VLF waves have maxima and minima at different altitudes, instead of being attenuated monotonically with altitude as expected. A theoretical model has been proposed which shows that the wave amplitude profiles are the result of interference between waves from an aperture area below the rocket. (5) We numerically calculated the absorption of VLF waves at the bottom of the ionosphere. The electron density gradient of the ionosphere was taken into account. The characteristics of the absorption, such as the frequency dependence, were investigated. Comparing the lightning spectrum received on the ground and by a rocket, we deduced that significant heating of the ionosphere is caused by lightning-generated VLF waves.

Li, Ya Qi.

259

National Center for Atmospheric Research annual report, fiscal year 1991. Report for 1 October 1990-30 September 1991  

SciTech Connect

The National Center for Atmospheric Research (NCAR) annual report for fiscal year 1991 is presented. NCAR's projects for the period included investigations of air pollution from the oil well fires in Kuwait, a solar eclipse, thunderstorms in central Florida, the El Nino current, greenhouse processes, and upper atmosphere phenomena.

Warner, L.

1992-06-01

260

Climate Sciences: Atmospheric Thermodynamics  

E-print Network

1 Climate Sciences: Atmospheric Thermodynamics Instructor: Lynn Russell, NH343 http://aerosol.ucsd.edu/courses.html Text: Curry & Webster Atmospheric Thermodynamics Ch1 Composition Ch2 Laws Ch3 Transfers Ch12 Energy Climate Sciences: Atmospheric Thermodynamics Instructor: Lynn Russell, NH343 http

Russell, Lynn

261

Atmospheric Turbulence (METR 6103)  

E-print Network

: A First Course in Turbulence, The MIT Press, 300 pp; Garratt, J. R., 1992: The Atmospheric Boundary Layer in the atmospheric boundary and surface layers. Similarity and scaling techniques. Monin-Obukhov similarity theory of turbulence closures. Large eddy simulation of atmospheric boundary layer flows. Note: Any student

Fedorovich, Evgeni

262

Atmospheric Physics Christoph Schr  

E-print Network

and climate modeling · Numerical modeling of weather and climate (Schär & Lohmann) · Boundary-layer1 Atmospheric Physics Christoph Schär Institute for Atmospheric and Climate Science ETH Zürich http between MeteoSwiss, DWD, CSCS, C2SM, ETH. One of the first real-case atmospheric models running mostly

Lang, Annika

263

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

264

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

265

Atmospheric Pressure Indicator.  

ERIC Educational Resources Information Center

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

Salzsieder, John C.

1995-01-01

266

Light-Front Holography and Novel QCD Phenomena  

E-print Network

Light-Front Holography and Novel QCD Phenomena Stan Brodsky 1 Valparaiso, Chile May 19-20, 2011 in the field o Particle and Nuclear Physics. Main Menu Home Registration Valparaiso, Chile May 19-20, 2011

Wechsler, Risa H.

267

High speed imaging of transient non-Newtonian fluid phenomena  

E-print Network

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

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

2004-01-01

268

Infrared thermometry study of nanofluid pool boiling phenomena  

E-print Network

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

Gerardi, Craig

269

Depicting fire and other gaseous phenomena using diffusion processes  

Microsoft Academic Search

Developing a visually convincing model of fire, smoke, and othergaseousphenomenaisamongthemostdifficult andattractive problems in computer graphics. We have created new methods of animating a wide range of gaseous phenomena, including the particularlysubtleproblemofmodelling\\

Jos Stam; Eugene Fiume

1995-01-01

270

Simulation and design optimization for linear wave phenomena on metamaterials  

E-print Network

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

Saà-Seoane, Joel

2011-01-01

271

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

E-print Network

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

McCauley, Alexander P. (Alexander Patrick)

2011-01-01

272

A Multi-Model Approach to Analysis of Environmental Phenomena  

Microsoft Academic Search

This paper introduces a novel data-driven methodology named Evolutionary Polynomial Regres- sion (EPR), which permits the multi-purpose modelling of physical phenomena, through the simultaneous solution of a number of models. Multipurpose modelling or \\

O. Giustolisi; A. Doglioni; B. W. Webb

273

Nonextensive Statistical Mechanics: Some Links with Astronomical Phenomena  

Microsoft Academic Search

A variety of astronomical phenomena appear to not satisfy the ergodic hypothesis in the relevant stationary state, if any.\\u000a As such, there is no reason for expecting the applicability of Boltzmann–Gibbs (BG) statistical mechanics. Some of these phenomena\\u000a appear to follow, instead, nonextensive statistical mechanics. In the same manner that the BG formalism is based on the entropy\\u000a S\\u000a BG=?k?

Constantino Tsallis; Domingo Prato; Angel R. Plastino

2004-01-01

274

Modeling of transient flow phenomena in continuous casting of steel  

Microsoft Academic Search

This paper describes initial efforts to develop and apply 3D finite-difference models to simulate transient flow in the mold. These transient flow phenomena include flow pattern oscillations caused by sudden changes in nozzle inlet conditions and rapid fluctuations in the molten steel?flux interface level at the top surface of the mold. The flow model incorporates interactions with other transport phenomena,

X. Huang; B. G. Thomas

1998-01-01

275

Therapeutic potential of atmospheric neutrons  

PubMed Central

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

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

2010-01-01

276

Nonisothermal Pluto atmosphere models  

SciTech Connect

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

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

1990-03-01

277

An Atmospheric Science Observing System Simulation Experiment (OSSE) Environment  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

278

Effect of atmospheric environment on the attenuation coefficient of light in water  

E-print Network

The attenuation coefficient of 532 nm light in water under different atmospheric conditions was investigated. Measurements were made over a two-year period at the same location and show that the attenuation coefficient is significantly influenced by the atmospheric environment. It is lowest when the atmospheric pressure is high and temperature is low, and is highest when the atmospheric pressure is low and temperature is high. The maximum attenuation coefficient of pure water in these studies was about three times the minimum value. The mechanism of the phenomena is discussed. These results are also important in underwater acoustics.

Liu, Juan; Tang, Yijun; Zhu, Kaixing; Ge, Yuan; Chen, Xuegang; He, Xingdao; Liu, Dahe

2014-01-01

279

Light flash phenomena induced by HzE particles  

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

280

Droplet and flame dynamics in combustion phenomena  

NASA Astrophysics Data System (ADS)

This dissertation presents theoretical and experimental results on binary droplet collision, flame-vortex interaction, and the structure, geometry and propagation of spherical and cylindrical premixed and diffusion flames. Regarding the study on the dynamics of binary droplet collision, it is shown that, by varying the density of the gas through its pressure and molecular weight, water and hydrocarbon droplets both exhibit five distinct regimes of collision outcomes, namely coalescences with minor and substantial deformations, bouncing, and near head-on and off-center separations after coalescences. Therefore previous observations, obtained at one atmosphere air for water droplet are extended and unified with hydrocarbon droplets. A coalescence/separation criterion was derived, which identifies the dominant factors of the impact inertia and viscous dissipation and agrees well with the experimental data. A front tracking numerical technique was then used to study the collision dynamics in detail, and the computation quantitatively simulates well the experimental outcome of the collision. It was found that the minimum gas gap between the droplets exhibits a non-monotonic dependence on the droplet kinetic energy, thereby explaining the non-monotonic transition between the collision regimes of coalescence and bouncing. Both computational and experimental results further show that the droplet collision time is close to its natural oscillation time. This front tracking method for droplet collision was then adopted to simulate the unsteady motion of a premixed flame upon its interaction with a flow vortex. It was shown that the initial vorticity field can be significantly distorted or even eliminated by the flame, being substituted by flame generated vorticity corresponding to the tilted flame element, as consequence of the flame instability development. A linear stability analysis and numerical simulation of the flame and vortex pair interaction in the presence of gravity further showed that the hydrostatic pressure can qualitatively change the vorticity development, and that the influence of gravity on the vorticity generation depends on the Froude number associated with the flame speed and the characteristic length scale of the vortex. Two auxiliary studies on the structure and dynamics of flames in the absence of gravity were performed. First the influence of flow rate and rotation on the structure and response of burner-stabilized spherical premixed flames was analyzed by the asymptotic method. The leading order solution which describes the non-rotating spherical flame was constructed, and various mechanisms for the stabilization of the curved flame were identified. Rotation was then included as a perturbation. It was found that flame is deformed into a pancake shape that may be flattened either at the poles or the equator, depending on the combined effects of Lewis number, flame stretch and ambient temperature. The second problem is concerned with the unsteady outwardly-spreading motion of a diffusion flame from a cylindrical porous burner. Laplace inversion with large or small values of time was used to show that the flame spreading is mainly controlled by the ambient oxidizer concentration relative to the fuel concentration, modified by the flow rate from the burner, and that the characteristic diffusion length can be significantly larger or smaller than the flame radius, with their ratio being related to the quasi-steady assumption.

Qian, Jun

1997-08-01

281

Cosmic dust in the earth's atmosphere  

NASA Astrophysics Data System (ADS)

This review discusses the magnitude of the cosmic dust input into the earth's atmosphere, and the resulting impacts from around 100 km to the earth's surface. Zodiacal cloud observations and measurements made with a spaceborne dust detector indicate a daily mass input of interplanetary dust particles ranging from 100 to 300 tonnes, which is in agreement with the accumulation rates of cosmic-enriched elements (Ir, Pt, Os and super-paramagnetic Fe) in polar ice cores and deep-sea sediments. In contrast, measurements in the middle atmosphere - by radar, lidar, high-flying aircraft and satellite remote sensing - indicate that the input is between 5 and 50 tonnes per day. There are two reasons why this huge discrepancy matters. First, if the upper range of estimates is correct, then vertical transport in the middle atmosphere must be considerably faster than generally believed; whereas if the lower range is correct, then our understanding of dust evolution in the solar system, and transport from the middle atmosphere to the surface, will need substantial revision. Second, cosmic dust particles enter the atmosphere at high speeds and undergo significant ablation. The resulting metals injected into the atmosphere are involved in a diverse range of phenomena, including: the formation of layers of metal atoms and ions; the nucleation of noctilucent clouds, which are a sensitive marker of climate change; impacts on stratospheric aerosols and O3 chemistry, which need to be considered against the background of a cooling stratosphere and geo-engineering plans to increase sulphate aerosol; and fertilization of the ocean with bio-available Fe, which has potential climate feedbacks.

Plane, John M. C.

2012-04-01

282

Remote detection of radioactive contamination in the atmosphere based on secondary optical and microwave radiation of atmospheric components  

NASA Astrophysics Data System (ADS)

The paper analyzes secondary phenomena of atmospheric radioactive pollution caused by activity of the nuclear cycle enterprises. These effects being as indicators for remote diagnostics of a radio-activity are discussed. Excitation of a molecular and gas component in the air and various chemical reactions under the action of radiation have been considered. As a result of these reactions, new aerosol and gaseous components in the form of the excited atoms and ions appear in the atmosphere and relax with emission including microwave and optical wavelengths. The observable luminescence of the air during the emergency events at the nuclea power stations are long enough to be dedected by modern receivers. Intensity of such radiation in a radioactive plume is estimated for ecological monitoring of the atmosphere. Aerosols appearing, as a result of UF6 hydrolysis, in the atmosphere and their behavior have been also shown to be detectable with remote sensing.

Chistyakova, Liliya K.; Penin, Sergei T.

1999-12-01

283

Lithosphere-atmosphere-ionosphere coupling as governing mechanism for preseismic short-term events in atmosphere and ionosphere  

NASA Astrophysics Data System (ADS)

We present a general concept of mechanisms of preseismic phenomena in the atmosphere and ionosphere. After short review of observational results we conclude: 1. Upward migration of fluid substrate matter (bubble) can lead to ousting of the hot water/gas near the ground surface and cause an earthquake (EQ) itself in the strength-weakened area; 2. Thus, time and place of the bubble appearance could be random values, but EQ, geochemistry anomaly and foreshocks (seismic, SA and ULF electromagnetic ones) are casually connected; 3. Atmospheric perturbation of temperature and density could follow preseismic hot water/gas release resulting in generation of atmospheric gravity waves (AGW) with periods in a range of 6-60min; 4. Seismo-induced AGW could lead to modification of the ionospheric turbulence and to the change of over-horizon radio-wave propagation in the atmosphere, perturbation of LF waves in the lower ionosphere and ULF emission depression at the ground.

Molchanov, O.; Fedorov, E.; Schekotov, A.; Gordeev, E.; Chebrov, V.; Surkov, V.; Rozhnoi, A.; Andreevsky, S.; Iudin, D.; Yunga, S.; Lutikov, A.; Hayakawa, M.; Biagi, P. F.

2004-11-01

284

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

NASA Astrophysics Data System (ADS)

Proton transport phenomena are of paramount importance for acid-base chemistry, energy transduction in biological organisms, corrosion processes, and energy conversion in electrochemical systems such as polymer electrolyte fuel cells. The relevance for such a plethora of materials and systems, and the ever-lasting fascination with the highly concerted nature of underlying processes drive research across disciplines in chemistry, biology, physics and chemical engineering. A proton never travels alone. Proton motion is strongly correlated with its environment, usually comprised of an electrolyte and a solid or soft host material. For the transport in nature's most benign proton solvent and shuttle, water that is, insights from ab initio simulations, matured over the last 15 years, have furnished molecular details of the structural diffusion mechanism of protons. Excess proton movement in water consists of sequences of Eigen-Zundel-Eigen transitions, triggered by hydrogen bond breaking and making in the surrounding water network. Nowadays, there is little debate about the validity of this mechanism in water, which bears a stunning resemblance to the basic mechanistic picture put forward by de Grotthuss in 1806. While strong coupling of an excess proton with degrees of freedom of solvent and host materials facilitates proton motion, this coupling also creates negative synergies. In general, proton mobility in biomaterials and electrochemical proton conducting media is highly sensitive to the abundance and structure of the proton solvent. In polymer electrolyte membranes, in which protons are bound to move in nano-sized water-channels, evaporation of water or local membrane dehydration due to electro-osmotic coupling are well-known phenomena that could dramatically diminish proton conductivity. Contributions in this special issue address various vital aspects of the concerted nature of proton motion and they elucidate important structural and dynamic effects of solvent, charge-bearing species at interfaces and porous host materials on proton transport properties. As a common thread, articles in this special issue contribute to understanding the functionality provided by complex materials, beyond hydrogen bond fluctuations in water. The first group of articles (Smirnov et al, Henry et al, Medvedev and Stuchebrukhov) elucidates various aspects of the impact of local structural fluctuations, hydrogen bonding and long-range electrostatic forces on proton transfer across and at the surface of mitochondrial membranes. The second group of articles (Ilhan and Spohr, Allahyarov et al and Idupulapati et al) employ molecular dynamics simulations to rationalize vital dependencies of proton transport mechanisms in aqueous-based polymer electrolyte membranes on the nanoporous, phase-separated ionomer morphology, and on the level of hydration. The articles by Gebel et al, Boillat et al, and Aleksandrova et al employ small angle neutron scattering, neutron radiography, and electrochemical atomic force microscopy, respectively, to obtain detailed insights into the kinetics of water sorption, water distribution, water transport properties, as well as spatial maps of proton conductivity in fuel cell membranes. The contribution of Paschos et al provides a comprehensive review of phosphate-based solid state protonic conductors for intermediate temperature fuel cells. The topic of proton conductive materials for high-temperature, water-free operation of fuel cells is continued in the article of Verbraeken et al which addresses synthesis and characterization of a proton conducting perovskite. The guest editor wishes to acknowledge and thank all contributing authors for their commitment to this special issue. Moreover, I would like to thank the staff at IOP Publishing for coordinating submission and refereeing processes. Finally, for the readers, I hope that this special issue will be a valuable and stimulating source of insights into the versatile and eminently important field of transport phenomena in proton conducting media. Complex dynamics of f

Eikerling, Michael

2011-06-01

285

Parameterized rotating convection for core and planetary atmosphere dynamics  

NASA Astrophysics Data System (ADS)

New types of convective instability and associated nonlinear phenomena in rapidly rotating spherical systems have been discovered through numerical simulations. The Prandtl number, defined as the ratio of the viscous and thermal diffusivities of a fluid, Pr = nu/kappa, plays a crucial role in determining the fundamental features of both the instabilities and the corresponding nonlinear convection. The results shed new light on regimes of convection in the earth's core and the atmospheres of the major planets.

Zhang, K.

1991-04-01

286

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

SciTech Connect

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

Cooper, T.D.

1996-09-30

287

The Mars atmosphere as seen from Curiosity  

NASA Astrophysics Data System (ADS)

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

Mischna, Michael

288

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

PubMed Central

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

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

2012-01-01

289

Pluto's atmosphere near perihelion  

SciTech Connect

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

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

1989-11-01

290

Photochemistry in planetary atmospheres  

NASA Technical Reports Server (NTRS)

Widely varying paths of evolutionary history, atmospheric processes, solar fluxes, and temperatures have produced vastly different planetary atmospheres. The similarities and differences between the earth atmosphere and those of the terrestrial planets (Venus and Mars) and of the Jovian planets are discussed in detail; consideration is also given to the photochemistry of Saturn, Uranus, Pluto, Neptune, Titan, and Triton. Changes in the earth's ancient atmosphere are described, and problems of interest in the earth's present troposphere are discussed, including the down wind effect, plume interactions, aerosol nucleation and growth, acid rain, and the fate of terpenes. Temperature fluctuations in the four principal layers of the earth's atmosphere, predicted decreases in the ozone concentration as a function of time, and spectra of particles in the earth's upper atmosphere are also presented. Finally, the vertical structure of the Venus cloud system and the thermal structure of the Jovian planets are shown graphically.

Levine, J. S.; Graedel, T. E.

1981-01-01

291

Measurement of the Atmospheric $\  

E-print Network

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

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

2012-01-01

292

Pluto's atmosphere near perihelion  

NASA Technical Reports Server (NTRS)

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

Trafton, L. M.

1989-01-01

293

Highly Evolved Exoplanet Atmospheres  

NASA Astrophysics Data System (ADS)

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

Hu, Renyu

2015-01-01

294

Relativistic breakdown in planetary atmospheres  

SciTech Connect

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

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

2007-04-15

295

Global Atmospheric Aerosol Modeling  

NASA Technical Reports Server (NTRS)

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

Hendricks, Johannes; Aquila, Valentina; Righi, Mattia

2012-01-01

296

Atmospheres from Within  

NASA Technical Reports Server (NTRS)

In this review of atmospheric investigations from planetary surfaces, a wide variety of measurement and instrument techniques relevant to atmospheric studies from future planetary lander missions are discussed. The diversity of planetary surface environments within the solar system precludes complete or highly specific coverage, but lander investigations for Mars and cometary missions are presented as specific cases that represent the broad range of atmospheric-surface boundaries and that also correspond to high priority goals for future national and international lander missions.

Morgan, Thomas; Abshire, James; Clancy, Todd; Fry, Ghee; Gustafson, Bo; Hecht, Michael; Kostiuk, Theodor; Rall, Jonathan; Reuter, Dennis; Sheldon, Robert

1996-01-01

297

Sources of atmospheric ammonia  

NASA Astrophysics Data System (ADS)

The information available on factors that influence emissions from the principal societal sources of ammonia to the atmosphere, namely combustion processes, volatilization of farm animal wastes, and volatilization of fertilizers, is reviewed. Emission factors are established for each major source of atmospheric ammonia. The factors are then multiplied by appropriate source characterization descriptors to obtain calculated fluxes of ammonia to the atmosphere on a state-by-state basis for the United States.

Harriss, R. C.; Michaels, J. T.

1982-05-01

298

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

299

Water in the Atmosphere  

NSDL National Science Digital Library

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

300

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

Microsoft Academic Search

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

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

2003-01-01

301

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.

none,

1992-07-01

302

Direct observation of thitherto unobservable quantum phenomena by using electrons  

PubMed Central

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

Tonomura, Akira

2005-01-01

303

Geochemical cycles of atmospheric gases  

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

304

Origin and evolution of planetary atmospheres  

NASA Technical Reports Server (NTRS)

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

Lewis, John S.

1992-01-01

305

Critical phenomena experiments in space. [for fluid phase-equilibrium  

NASA Technical Reports Server (NTRS)

The paper analyzes several types of critical phenomena in fluids, shows how they are affected by the presence of gravity, and describes how experiments conducted in an orbiting laboratory under low gravity conditions could extend the range of measurements needed to study critical phenomena. Future experiments are proposed. One would be a careful measurement of the dielectric constant in a low gravity environment. Two basic problems that can benefit especially from space experiments are the specific heat near the critical point and the shear viscosity at the gas-liquid critical point.

Sengers, J. V.; Moldover, M. R.

1978-01-01

306

On microtransport phenomena in minute droplets: A critical review  

SciTech Connect

Liquid droplets are abundant in nature and industry. Their industrial applications are very broad. They appear in the forms of sessile, impinging, and hanging/suspending droplets, undergoing evaporation or solidification depending upon ambient conditions. In the present article, a critical review is presented for the important literature pertinent to microtransport phenomena in minute droplets. Thermocapillarity is the principal motivating force in convective heat and mass transfer, phase change, and instability inside the droplets, supplemented in part by the buoyancy force. The dimensionless governing parameters are identified and their roles in droplet transport phenomena are determined. This article includes 135 references.

Aydin, O.; Yang, W.J.

2000-05-01

307

Risk in nuclear power plants due to natural hazard phenomena  

SciTech Connect

For the safety of nuclear power plants, it is important to identify potential areas of vulnerabilities to internal as well as external events to which nuclear power plants are exposed. This paper summarizes the risk in nuclear power plants due to natural hazard phenomena such as earthquakes, winds and tornadoes, floods, etc. The reported results are based on a limited number of probabilistic risk assessments (PRAS) performed for a few of the operating nuclear power plants within the United States. The summary includes an importance ranking of various natural hazard phenomena based on their contribution to the plant risk along with insights observed from the PRA studies.

Lu, S.C. [Lawrence Livermore National Lab., CA (United States)

1995-12-01

308

A numerical simulation of the phenomena in Be plasma  

NASA Astrophysics Data System (ADS)

In this paper, we present the numerical simulation of the Be deposition phenomena using the Thermionic Vacuum Arc (TVA) method. The Be marker layer must be adherent to the substrate and compact to resemble bulk beryllium. Thermionic Vacuum Arc (TVA) is an externally heated cathode arc which can be established in high vacuum condition, in vapors of the anode material. The arc is ignited between a heated cathode provided with a Whenelt cylinder and the anode which is a crucible containing the material to be evaporated [1]. We have used the COMSOL software to simulate the Be deposition phenomena using the TVA method.

Gavrila, Camelia; Lungu, Cristian P.; Gruia, Ion

2011-05-01

309

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, J.E.

1999-09-01

310

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

311

Polarization phenomena in the reaction p+?-->p+?0+?  

NASA Astrophysics Data System (ADS)

We present a general analysis of polarization phenomena for three-body processes (in noncoplanar kinematics), in terms of a P- and T-odd acoplanarity parameter. The spin structure of the matrix element and the polarization phenomena contain new contributions, with respect to binary processes, which can be conveniently expressed as functions of this parameter. We apply this formalism to the reaction p+?-->p+?0+?, in view of characterizing the different mechanisms involved and studying the excitation of the Roper resonance. We find that the polarization transfer coefficient Dnn, where n--> is normal to the proton scattering plane, is especially sensitive to the spin of the exchanged particle.

Rekalo, Michail P.; Tomasi-Gustafsson, Egle

2001-05-01

312

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

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

313

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 ...

314

Pluto's Increasing Atmospheric Pressure  

Microsoft Academic Search

In 2007, the occultation of a V=13.2 magnitude star was successfully observed from Mt. John Observatory, Mt. Canopus Observatory and our 14-inch Meade portable system in Musselroe Bay, New Zealand. We simultaneously fit an isothermal model atmosphere (Eliot and Young, 1992) to the main drop and recovery of the observed occultation light curves to derive global atmospheric parameters and a

Catherine B. Olkin; L. Young; E. Young; M. Buie; R. Howell; J. Regester; C. Ruhland

2009-01-01

315

Atmospheric Thermodynamics Composition  

E-print Network

1 Atmospheric Thermodynamics Ch1 Composition Ch2 Laws Ch3 Transfers Ch12 EnergyBalance Ch4 Water Ch Sciences: Atmospheric Thermodynamics Instructor: Lynn Russell, NH343 http #12;2 Review from Ch. 1 · Thermodynamic quantities · Composition · Pressure · Density · Temperature

Russell, Lynn

316

The atmospheric vortex engine  

Microsoft Academic Search

Mechanical energy is produced when heat is carried upward by convection in the atmosphere. An atmospheric vortex engine (AVE) uses an artificially created anchored tornado like vortex to capture the mechanical energy produced during upward heat convection. The vortex is created by admitting warm or humid air tangentially into the base of a circular wall. The heat source can be

Louis M. Michaud

2009-01-01

317

Controlled Atmosphere Stunning  

Microsoft Academic Search

Controlled atmosphere (CAS) stunning includes several variations of gaseous mixtures given to induce an anaesthetic state before slaughter poultry. One method of multi phase CAS is to unload the birds out of the crate on a conveyor belt and subject the birds to an atmosphere of 30% O2, 40% CO2 and 30% N2 for 1 min to stun them followed

E. Lambooij; M. A. Gerritzen

2009-01-01

318

MODIS Atmospheric Data Handler  

NASA Technical Reports Server (NTRS)

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

Anantharaj, Valentine; Fitzpatrick, Patrick

2008-01-01

319

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.

Betsy Youngman

320

Titan's Lower Atmosphere  

NASA Astrophysics Data System (ADS)

Saturn's largest moon, Titan, sports an atmosphere 10 times thicker than Earth's. Like Earth, the moon's atmosphere is N2 based and possesses a rich organic chemistry. In addition, similar to the terrestrial hydrological cycle, Titan has a methane cycle, with methane clouds, rain and seas. Presently, there is a revolution in our understanding of the moon, as data flows in and is analyzed from the NASA and ESA Cassini-Huygens mission. For example, seas were detected only this year. Here I will discuss the evolution of our understanding of Titan's atmosphere, its composition, chemistry, dynamics and origin. Current open questions will also be presented. Studies of Titan's atmosphere began and evolved to the present state in less time than that of a single scientist's career. This short interlude of activity demonstrates the rigors of the scientific method, and raises enticing questions about the workings and evolution of an atmosphere.

Griffith, Caitlin Ann

2007-09-01

321

The Mars reference atmosphere  

NASA Technical Reports Server (NTRS)

A nominal atmospheric model of Mars is presented, with detailed consideration being given to the various sources of variability in the Martian atmosphere. A basic model for the midlatitude summer is outlined for the northern and southern hemispheres. Attention is given to meteorological variability due to winds, diurnal and seasonal pressure variations, temperature changes, and the effects of dust opacity, particularly on temperature stratification. Viking lander IR thermal mapper data are examined in terms of diurnal and latitudinal temperature variations, and cloud and haze formation and locations are discussed. Mass spectrometry of the atmosphere is used to describe the molecular abundances, and water vapor measurements are reviewed. Finally, radio occultation, UV airglow, and mass spectrometry of the Martian upper atmosphere are investigated, along with the temperature structure of the upper atmosphere.

Kliore, A.

1982-01-01

322

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

323

Investigation of a CCD camera for measurements of optical atmospheric turbulence  

NASA Astrophysics Data System (ADS)

Atmospheric turbulence introduces random phase distortions in optical imaging systems. The development of new laser and imaging systems requires information on the spatial and temporal distribution of this atmospheric turbulence. Measurements of the image spread and the jitter induced by the atmosphere on an optical system provide two techniques to quantify these phenomena. This thesis evaluates a Spectra Sources Lynxx PC Plus charge coupled device (CCD) array as an atmospheric turbulence sensor. Data acquisition and processing programs were written to measure the image spread of a point source and centroid jitter of a point source imaged through the atmosphere. Since atmospheric jitter measurements require high image frame rates, on the order of 200 images per second, a large portion of this thesis involved measurements of the times for the CCD detector, interface board, and IBM compatible computer to perform their tasks. Recommendations for higher performance are presented.

Rall, William J.

1992-03-01

324

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

325

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

EPA Science Inventory

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

326

New phenomena predicted for films on weak-binding surfaces  

Microsoft Academic Search

Adsorption of 4He and para-H2 is predicted to exhibit exotic properties on weak-binding surfaces. For 4He, alternative scenarios include nonwetting, prewetting and a Bose gas monolayer. For H2, a monolayer superfluid phase can be created by a suitable choice of the substrate. Intriguing phenomena are predicted for 3He\\/4He mixtures in multilayer films.

E. Cheng; A. Chizmeshya; M. W. Cole; J. R. Klein; J. Ma; W. F. Saam; J. Treiner

1991-01-01

327

Coherent Twinning Phenomena: Towards Twinning Superlattices in III-V  

E-print Network

Coherent Twinning Phenomena: Towards Twinning Superlattices in III-V Semiconducting Nanowires Qihua an additional series of diffraction peaks consistent with a quasiperiodic placement of twinning boundaries along.e., the distance between twin boundaries, has been found to depend on the temperature gradient imposed

Xiong, Qihua

328

Designing and conducting online interviews to investigate interesting consumer phenomena  

Microsoft Academic Search

Purpose – The purpose of this paper is to thoroughly explain how qualitative researchers can design and conduct online interviews to investigate interesting consumer phenomena. Design\\/methodology\\/approach – A semi-standardized qualitative technique called laddering was applied successfully to an online environment. Laddering allows researchers to reach deeper levels of reality and to reveal the reasons behind the reasons. A web survey

Thorsten Gruber; Isabelle Szmigin; Alexander E. Reppel; Roediger Voss

2008-01-01

329

Interfacial Bonding and Fracture Phenomena between Porcelain and Metal Coping  

Microsoft Academic Search

In last few decades, the porcelain fused to metal crown has been a successful dental restoration and many studies are worked and evaluated, but increasing availability of new base metal alloys demands constant evaluation of bonding and fracture between porcelain and metal coping. The aim of this study is to identify fracture phenomena and to measure bonding strength between porcelain

J. S. Park; H. S. Kim; M. K. Son; H. C. Choe

2011-01-01

330

A thermodynamic approach for cooperative phenomena in magnetic materials  

NASA Astrophysics Data System (ADS)

A statistical thermodynamic approximation for cooperative phenomena in magnetic materials is proposed, improving constant coupling approximation by introduction of a second pairs quasichemical reaction after averaging atomic groups. With suitable temperature functions related to fluctuations, analytical expressions for free energies of Ising and Heisenberg systems are obtained and applied.

Cavallotti, P. L.; Colombi, B.; Nobili, L.; Ossi, P. M.; Colombo, M.

1990-01-01

331

SELF-PERCEPTION: AN ALTERNATIVE INTERPRETATION OF COGNITIVE DISSONANCE PHENOMENA  

Microsoft Academic Search

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

DARYL J. BEM

1967-01-01

332

Electronic and plasmonic phenomena at graphene grain boundaries  

E-print Network

our highly doped graphene films, we chose infrared light with lIR close to 10 mm and AFM tips with RElectronic and plasmonic phenomena at graphene grain boundaries Z. Fei1 , A. S. Rodin2 , W. Gannett. Basov1 * Graphene1, a two-dimensional honeycomb lattice of carbon atoms of great interest in (opto

Zettl, Alex

333

Coastal Sand Dune Plant Ecology: Field Phenomena and Interpretation  

ERIC Educational Resources Information Center

Discusses the advantages and disadvantages of selecting coastal sand dunes as the location for field ecology studies. Presents a descriptive zonal model for seaboard sand dune plant communities, suggestions concerning possible observations and activities relevant to interpreting phenomena associated with these forms of vegetation, and additional…

McDonald, K.

1973-01-01

334

Hydraulic Fractures: multiscale phenomena, asymptotic and numerical solutions  

E-print Network

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

Peirce, Anthony

335

Hydraulic Fractures: multiscale phenomena, asymptotic and numerical solutions  

E-print Network

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

Peirce, Anthony

336

Review of the literature on Sondhauss thermoacoustic phenomena  

Microsoft Academic Search

The phenomena of acoustical pressure oscillations generated in a gas by a steady heat source may be separated into two distinct types: (i) Sondhauss oscillations which occur in a pipe having one end closed and one open; (ii) Rijke oscillations which occur in a pipe having both ends open. In this paper the available literature on Sondhauss oscillations is listed

K. T. Feldman

1968-01-01

337

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

E-print Network

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

Fisher, Frank

338

Linguistic Studies on English Pronominalization: Syntactic, Discourse and Pragmatic Phenomena.  

ERIC Educational Resources Information Center

To integrate many of the theoretical linguistic studies examining pronoun reference, this paper focuses on tracing the shift from purely transformational syntactic studies of intrasentential phenomena to the wider orientations of discourse and pragmatic studies. The first section describes the classic studies of pronominalization within the…

Barnitz, John G.

339

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

340

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

341

Pinning phenomena in the GinzburgLandau Model of Superconductivity  

E-print Network

Pinning phenomena in the Ginzburg­Landau Model of Superconductivity Amandine Aftalion Laboratoire d a homogenized medium in the material. 1 #12; I Introduction Superconducting materials have the property of expelling an applied magnetic field. In fact, the behaviour of a superconducting sample varies according

Serfaty, Sylvia

342

Cooperative and concentrative phenomena of swimming micro-organisms  

Microsoft Academic Search

This paper describes linear and co-operative phenomena based on the dynamics of the trajectories of swimming cells. The swimming direction of algal cells can be guided so as to focus the cells into a concentrated beam. This directed locomotion, or taxis, results from the orientation of the cells' axes by compensating gravitational and viscous torques. It is named gyrotaxis because

John O. Kessler

1985-01-01

343

Discrimination of geophysical phenomena in satellite radar interferograms  

Microsoft Academic Search

Various geophysical phenomena are recorded in the interference patterns formed by differencing two synthetic aperture radar (SAR) images. The fringes generated by the topographic relief can be removed using a digital elevation model (DEM). The remaining fringes map the change in satellite-to-ground range which occurred between the acquisition times of the two images. By comparing different pairs of images spanning

Didier Massonnet; Kurt L. Feigl

1995-01-01

344

Some Remarks on Critical Phenomena of Fluid Metals  

Microsoft Academic Search

Critical phenomena of fluid metals are studied by observing the potential range of effective ion-ion interaction in their liquid phases. This is done by two different methods. First, the Fourier transform of March's potential with a cutoff is calculated. Secondly, by means of quantum mechanical perturbation theory, the effective potential is derived and discussed within the lowest order approximation for

Ryuzo Abe

1989-01-01

345

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

2013-09-01

346

General Search for New Phenomena in ep Scattering at HERA  

E-print Network

General Search for New Phenomena in ep Scattering at HERA The IVIIth Rencontres de Moriond on QCD algorithm investigate all final states produced at high PT in ep collisions do not rely on assumptions about 3 General Search @ H1 Data samples HERA I (1992-2000) HERA II (2002-2007) HERA I: e+p dominated (GS

347

MATERIALS, INTERFACES, AND ELECTROCHEMICAL PHENOMENA Hydrophilic Zeolite Coatings for Improved  

E-print Network

MATERIALS, INTERFACES, AND ELECTROCHEMICAL PHENOMENA Hydrophilic Zeolite Coatings for Improved Heat on the surface of a bare, ZSM-5 coated, and Zeolite-A coated stainless steel 304 substrate at different initial surface temperatures was experimentally studied. ZSM-5 and Zeolite-A coated SS-304 are more much more

Aguilar, Guillermo

348

Searches for New Phenomena Beate Heinemann, University of Liverpool  

E-print Network

Searches for New Phenomena Beate Heinemann, University of Liverpool Introduction Supersymmetry Extra Dimensions Summary and Outlook #12;ICHEP '04, 20.08.2004 B. Heinemann, University of Liverpool 2 of Liverpool 3 Beyond the Standard Model Why not the Standard Model? Hierarchy problem: mh

Fermilab

349

Threshold phenomena in erosion driven by subsurface flow  

E-print Network

Threshold phenomena in erosion driven by subsurface flow Alexander E. Lobkovsky Department of Earth of the three modes of sediment mobilization in this experiment: surface erosion, fluidization, and slumping. The onset of erosion is controlled not only by shear stresses caused by surfical flows but also

Kudrolli, Arshad

350

A model for transfer phenomena in structured populations  

E-print Network

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

Hinow, Peter

351

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

352

TEMPERATURE EFFECTS AND TRANSPORT PHENOMENA IN TERAHERTZ QUANTUM CASCADE LASERS  

E-print Network

TEMPERATURE EFFECTS AND TRANSPORT PHENOMENA IN TERAHERTZ QUANTUM CASCADE LASERS BY PHILIP C Quantum cascade lasers (QCL's) employ the mid- and far-infrared intersubband ra- diative transitions been possible without his ability to explain the often frustrating physics of quantum cascade lasers. I

Massachusetts at Lowell, University of

353

Investigation of Transient Phenomena of Proton Exchange Membrane Fuel Cells  

E-print Network

Investigation of Transient Phenomena of Proton Exchange Membrane Fuel Cells by Roongrojana of Proton Exchange Membrane Fuel Cells by Roongrojana Songprakorp BSc, Prince of Songkhla University to the modeling and under- standing of the dynamic behavior of proton exchange membrane fuel cells (PEMFCs

Victoria, University of

354

Geosimulation: object-based modeling of urban phenomena  

E-print Network

Editorial Geosimulation: object-based modeling of urban phenomena 1. Introduction Urban simulation an ``evolutionary'' phase, which has spanned the last two decades. A ``new wave'' of urban models have begun to take as collectives of numer- ous elements acting in the city. These ``new wave'' urban models are more likely

Tesfatsion, Leigh

355

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

356

Contemporary Active Research Groups in Japan for Anomalous Phenomena  

Microsoft Academic Search

There are few English reports dealing with contemporary Japanese research groups for anomalous phenomena. In this paper, the author describes the modern Japanese scene focusing on activities of academic or scientific groups. The most active researchers have experienced a number of social upheavals in their lives. Therefore, the author has taken the historical term \\

Hideyuki Kokubo

357

Electromagnetically and Thermally Driven Flow Phenomena in Electroslag Welding  

E-print Network

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

Eagar, Thomas W.

358

Sensitivity of an Ocean-Atmosphere Coupled Model to the Coupling Method : Study of Tropical Cyclone  

E-print Network

Sensitivity of an Ocean-Atmosphere Coupled Model to the Coupling Method : Study of Tropical Cyclone) in a realistic configuration aiming at simulating the genesis and propagation of tropical cyclone Erica energetic and complex phenomena like tropical cyclones, eastern boundary upwellings (e.g. Bao et al., 2000

Recanati, Catherine

359

Sensitivity of Ocean-Atmosphere Coupled Models to the Coupling Method : Example of Tropical Cyclone  

E-print Network

Sensitivity of Ocean-Atmosphere Coupled Models to the Coupling Method : Example of Tropical Cyclone and propagation of tropical cyclone Erica. Sensitiv- ity tests to the coupling method are carried out-way coupling is essential for analyzing energetic and complex phenomena like tropical cyclones (e.g. Bao et al

360

Exploring NASA and ESA Atmospheric Data Using GIOVANNI, the Online Visualization and Analysis Tool  

NASA Technical Reports Server (NTRS)

Giovanni, the NASA Goddard online visualization and analysis tool (http://giovanni.gsfc.nasa.gov) allows users explore various atmospheric phenomena without learning remote sensing data formats and downloading voluminous data. Using NASA MODIS (Terra and Aqua) and ESA MERIS (ENVISAT) aerosol data as an example, we demonstrate Giovanni usage for online multi-sensor remote sensing data comparison and analysis.

Leptoukh, Gregory

2007-01-01

361

Internal Waves in the Atmosphere from High-Resolution Radar Measurements  

Microsoft Academic Search

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

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

1970-01-01

362

The NetLander atmospheric instrument system (ATMIS): description 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 Global Surveyor have given a good understanding of the basic behaviour of the Martian atmosphere. However, the more detailed characterisation of the Martian circulation patterns, boundary layer phenomena and climatological cycles

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

2000-01-01

363

Early attempts at atmospheric simulations for the Cherenkov Telescope Array  

E-print Network

The Cherenkov Telescope Array (CTA) will be the world's first observatory for detecting gamma-rays from astrophysical phenomena and is now in its prototyping phase with construction expected to begin in 2015/16. In this work we present the results from early attempts at detailed simulation studies performed to assess the need for atmospheric monitoring. This will include discussion of some lidar analysis methods with a view to determining a range resolved atmospheric transmission profile. We find that under increased aerosol density levels, simulated gamma-ray astronomy data is systematically shifted leading to softer spectra. With lidar data we show that it is possible to fit atmospheric transmission models needed for generating lookup tables, which are used to infer the energy of a gamma-ray event, thus making it possible to correct affected data that would otherwise be considered unusable.

Rulten, Cameron B

2014-01-01

364

Web-Based Data Processing System for Automated Detection of Oscillations with Applications to the Solar Atmosphere  

Microsoft Academic Search

A web-based, interactive system for the remote processing of imaging data sets (i.e., EUV, X-ray, and microwave) and the automated interactive detection of wave and oscillatory phenomena in the solar atmosphere\\u000a is presented. The system targets localized, but spatially resolved, phenomena such as kink, sausage, and longitudinal propagating\\u000a and standing waves. The system implements the methods of Periodmapping for pre-analysis,

R. A. Sych; V. M. Nakariakov; S. A. Anfinogentov; L. Ofman

2010-01-01

365

Web-Based Data Processing System for Automated Detection of Oscillations with Applications to the Solar Atmosphere  

Microsoft Academic Search

A web-based, interactive system for the remote processing of imaging data sets ( i.e., EUV, X-ray, and microwave) and the automated interactive detection of wave and oscillatory phenomena in the solar atmosphere is presented. The system targets localized, but spatially resolved, phenomena such as kink, sausage, and longitudinal propagating and standing waves. The system implements the methods of Periodmapping for

R. A. Sych; V. M. Nakariakov; S. A. Anfinogentov; L. Ofman

2010-01-01

366

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.

367

Advanced studies on Simulation Methodologies for very Complicated Fracture Phenomena  

NASA Astrophysics Data System (ADS)

Although nowadays, computational techniques are well developed, for Extremely Complicated Fracture Phenomena, they are still very difficult to simulate, for general engineers, researchers. To overcome many difficulties in those simulations, we have developed not only Simulation Methodologies but also theoretical basis and concepts. We sometimes observe extremely complicated fracture patterns, especially in dynamic fracture phenomena such as dynamic crack branching, kinking, curving, etc. For examples, although the humankind, from primitive men to modern scientists such as Albert Einstein had watched the post-mortem patterns of dynamic crack branching, the governing condition for the onset of the phenomena had been unsolved until our experimental study. From in these studies, we found the governing condition of dynamic crack bifurcation, as follows. When the total energy flux per unit time into a propagating crack tip reaches the material crack resistance, the crack braches into two cracks [total energy flux criterion]. The crack branches many times whenever the criterion is satisfied. Furthermore, the complexities also arise due to their time-dependence and/or their-deformation dependence. In order to make it possible to simulate such extremely complicated fracture phenomena, we developed many original advanced computational methods and technologies. These are (i)moving finite element method based on Delaunay automatic triangulation (MFEMBOAT), path independent,(ii) equivalent domain integral expression of the dynamic J integral associated with a continuous auxiliary function,(iii) Mixed phase path-prediction mode simulation, (iv) implicit path prediction criterion. In this paper, these advanced computational methods are thoroughly explained together with successful comparison with the experimental results. Since multiple dynamic crack branching phenomena may be most complicated fracture due to complicated fracture paths, and its time dependence (transient), this simulation and numerical results are mainly explained.

Nishioka, Toshihisa

2010-06-01

368

Reference Atmosphere for Mercury  

NASA Technical Reports Server (NTRS)

We propose that Ar-40 measured in the lunar atmosphere and that in Mercury's atmosphere is due to current diffusion into connected pore space within the crust. Higher temperatures at Mercury, along with more rapid loss from the atmosphere will lead to a smaller column abundance of argon at Mercury than at the Moon, given the same crustal abundance of potassium. Because the noble gas abundance in the Hermean atmosphere represents current effusion, it is a direct measure of the crustal potassium abundance. Ar-40 in the atmospheres of the planets is a measure of potassium abundance in the interiors, since Ar-40 is a product of radiogenic decay of K-40 by electron capture with the subsequent emission of a 1.46 eV gamma-ray. Although the Ar-40 in the Earth's atmosphere is expected to have accumulated since the late bombardment, Ar-40 in the atmospheres of Mercury and the Moon is eroded quickly by photoionization and electron impact ionization. Thus, the argon content in the exospheres of the Moon and Mercury is representative of current effusion rather than accumulation over the lifetime of the planet.

Killen, Rosemary M.

2002-01-01

369

Atmospheric and adaptive optics  

NASA Astrophysics Data System (ADS)

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

Hickson, Paul

2014-11-01

370

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

371

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

372

Introduction to the Atmosphere  

NSDL National Science Digital Library

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

373

Triton's Distorted Atmosphere  

NASA Technical Reports Server (NTRS)

A stellar-occultation light curve for Triton shows asymmetry that can be understood if Triton's middle atmosphere is distorted from spherical symmetry. Although a globally oblate model can explain the data, the inferred atmospheric flattening is so large that it could be caused only by an unrealistic internal mass distribution or highly supersonic zonal winds. Cyclostrophic winds confined to a jet near Triton's northern or southern limbs (or both) could also be responsible for the details of the light curve, but such winds are required to be slightly supersonic. Hazes and clouds in the atmosphere are unlikely to have caused the asymmetry in the light curve.

Elliot, J. L.; Stansberry, J. A.; Olkin, C. B.; Agner, M. A.; Davies, M. E.

1998-01-01

374

The cosmic dust input to the earth's atmosphere  

NASA Astrophysics Data System (ADS)

This paper will address a fundamental problem - the size of the cosmic dust input to the earth's atmosphere. Zodiacal cloud observations and spaceborne dust detectors indicate a daily input of 100 - 300 tonnes, in agreement with the accumulation rates of cosmic elements (Ir, Pt, Os and super-paramagnetic Fe) in polar ice cores and deep-sea sediments. In contrast, measurements in the middle and upper atmosphere - by radars, lidars, high-flying aircraft and satellite remote sensing - indicate that the input is only 2 - 30 tonnes. There are two major reasons why this huge discrepancy matters. First, if the upper range of estimates is correct, then vertical transport in the middle atmosphere must be considerably faster than generally believed; whereas if the lower range is correct, then our understanding of dust production and evolution in the solar system, and transport from the middle atmosphere to the surface, will need substantial revision. Second, cosmic dust particles enter the atmosphere at high speeds and in most cases completely ablate. The resulting metals injected into the atmosphere are involved in a diverse range of phenomena, including: formation of layers of metal atoms and ions; nucleation of noctilucent clouds; impacts on stratospheric aerosols and O3 chemistry; and fertilization of the ocean with bio-available Fe, which has potential climate feedbacks.

Plane, John

2013-04-01

375

Current status and challenges in optical turbulence simulations in various layers of the Earth's atmosphere  

NASA Astrophysics Data System (ADS)

In this study, we present a brief review on the existing approaches for optical turbulence estimation in various layers of the Earth's atmosphere. The advantages and disadvantages of these approaches are also discussed. An alternative approach, based on mesoscale modeling with parameterized turbulence, is proposed and tested for the simulation of refractive index structure parameter (C2n ) in the atmospheric boundary layer. The impacts of a few atmospheric flow phenomena (e.g., low-level jets, island wake vortices, gravity waves) on optical turbulence are discussed. Consideration of diverse geographic settings (e.g., flat terrain, coastal region, ocean islands) makes this study distinct.

He, Ping; Nunalee, Christopher G.; Basu, Sukanta; Vorontsov, Mikhail A.; Fiorino, Steven T.

2014-10-01

376

Hypervelocity atmospheric flight: Real gas flow fields  

NASA Technical Reports Server (NTRS)

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

Howe, John T.

1990-01-01

377

Hypervelocity atmospheric flight: Real gas flow fields  

NASA Technical Reports Server (NTRS)

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

Howe, John T.

1989-01-01

378

Atmospheric optical calibration system  

DOEpatents

An atmospheric optical calibration system is provided to compare actual atmospheric optical conditions to standard atmospheric optical conditions on the basis of aerosol optical depth, relative air mass, and diffuse horizontal skylight to global horizontal photon flux ratio. An indicator can show the extent to which the actual conditions vary from standard conditions. Aerosol scattering and absorption properties, diffuse horizontal skylight to global horizontal photon flux ratio, and precipitable water vapor determined on a real-time basis for optical and pressure measurements are also used to generate a computer spectral model and for correcting actual performance response of a photovoltaic device to standard atmospheric optical condition response on a real-time basis as the device is being tested in actual outdoor conditions. 7 figs.

Hulstrom, R.L.; Cannon, T.W.

1988-10-25

379

Atmospheric optical calibration system  

DOEpatents

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

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

1988-01-01

380

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.

381

INTRODUCTIONTOTHE SOLAR ATMOSPHERE  

E-print Network

;#12;UV/EUV SPECTRUM · Mostly emission lines with low continuum · Lyman series NASA/ESA, SOHO/SUMER #12() through atmosphere #12;MAGNETIC FIELD · Presence of magnetic field polarizes EM field · Four Stokes

382

8, 10691088, 2008 Atmospheric  

E-print Network

Discussion EGU Abstract Smog chamber/FTIR techniques were used to study the products and mechanisms of OH the atmospheric oxi- dation products of trans-CF3CH=CHF. Specifically, smog chamber/FTIR techniques were used

Boyer, Edmond

383

Planetary Science (mostly atmospheres)  

E-print Network

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

Withers, Paul

384

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

385

Atmospheric Laser Communication  

Microsoft Academic Search

Atmospheric laser communication, often referred to as free-space optics (FSO) or free-space laser (FSL) communication, is similar to fiber optic cable in terms of carrier wavelength and bandwidth capability, but data are transmitted directly through the atmosphere via laser beams over paths from a few meters to 4 km or longer. FSL uses lasers in the near-infrared spectrum, typically at

Kenneth W. Fischer; Michael R. Witiw; T. R. Oke

2004-01-01

386

Study of atmospheric dynamics  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

387

Atmospheric Neutrinos in SNO  

NASA Astrophysics Data System (ADS)

The Sudbury Neutrino Observatory (SNO) was designed primarily to detect solar neutrinos. Its detection of atmospheric neutrinos, however, will be a nice bonus, providing an independent flux measurement in a geomagnetic environment very different from SuperKamiokande. This talk will provide a brief overview of atmospheric neutrino detection in SNO, including the advantages that come from being 2 km underground, as well as further detail on what we expect to see and some of what has been seen so far.

Nally, Christian

2000-05-01

388

Dynamics of Triton's atmosphere  

NASA Astrophysics Data System (ADS)

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

Ingersoll, A. P.

1990-03-01

389

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

390

Superthermal electron processes in the upper atmosphere of Uranus - Aurora and electroglow  

NASA Technical Reports Server (NTRS)

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.; Cravens, T. E.

1988-01-01

391

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

NASA Technical Reports Server (NTRS)

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

392

Protein Crystallization: Specific Phenomena and General Insights on Crystallization Kinetics  

NASA Technical Reports Server (NTRS)

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

Rosenberger, F.

1998-01-01

393

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

394

Modeling of convection phenomena in Bridgman-Stockbarger crystal growth  

NASA Technical Reports Server (NTRS)

Thermal convection phenomena in a vertically oriented Bridgman-Stockbarger apparatus were modeled by computer simulations for different gravity conditions, ranging from earth conditions to extremely low gravity, approximate space conditions. The modeling results were obtained by the application of a state-of-the art, transient, multi-dimensional, completely densimetrically coupled, discrete-element computational model which was specifically developed for the simulation of flow, temperature, and species concentration conditions in two-phase (solid-liquid) systems. The computational model was applied to the simulation of the flow and the thermal conditions associated with the convection phenomena in a modified Germanium-Silicon charge enclosed in a stationary fused-silica ampoule. The results clearly indicated that the gravitational field strength influences the characteristics of the coherent vortical flow patterns, interface shape and position, maximum melt velocity, and interfacial normal temperature gradient.

Carlson, F. M.; Eraslan, A. H.; Sheu, J. Z.

1985-01-01

395

Tank Pressure Control Experiment/thermal Phenomena (TPCE/TP)  

NASA Technical Reports Server (NTRS)

The 'Tank Pressure Control Experiment/Thermal Phenomena (TPCE/TP)' is a reflight of the tank pressure control experiment (TPCE), flown on STS-43 in a standard Get-Away Special (GAS) container in August 1991. The TPCE obtained extensive video and digital data of the jet induced mixing process in a partially filled tank in low gravity environments. It also provided limited data on the thermal processes involved. The primary objective of the reflight of TPCE is to investigate experimentally the phenomena of liquid superheating and pool nucleate boiling at very low heat fluxes in a long duration low gravity environment. The findings of this experiment will be of direct relevance to space based subcritical cryogenic fluid system design and operation. Experiment hardware and results from the first TPCE are described in outline and graphic form.

Hasan, M. M.; Knoll, R. H.

1992-01-01

396

Musical obsessions: a comprehensive review of neglected clinical phenomena.  

PubMed

Intrusive musical imagery (IMI) consists of involuntarily recalled, short, looping fragments of melodies. Musical obsessions are distressing, impairing forms of IMI that merit investigation in their own right and, more generally, research into these phenomena may broaden our understanding of obsessive-compulsive disorder (OCD), which is phenomenologically and etiologically heterogeneous. We present the first comprehensive review of musical obsessions, based on the largest set of case descriptions ever assembled (N=96). Characteristics of musical obsessions are described and compared with normal IMI, musical hallucinations, and visual obsessional imagery. Assessment, differential diagnosis, comorbidity, etiologic hypotheses, and treatments are described. Musical obsessions may be under-diagnosed because they are not adequately assessed by current measures of OCD. Musical obsessions have been misdiagnosed as psychotic phenomena, which has led to ineffective treatment. Accurate diagnosis is important for appropriate treatment. Musical obsessions may respond to treatments that are not recommended for prototypic OCD symptoms. PMID:24997394

Taylor, Steven; McKay, Dean; Miguel, Euripedes C; De Mathis, Maria Alice; Andrade, Chittaranjan; Ahuja, Niraj; Sookman, Debbie; Kwon, Jun Soo; Huh, Min Jung; Riemann, Bradley C; Cottraux, Jean; O'Connor, Kieron; Hale, Lisa R; Abramowitz, Jonathan S; Fontenelle, Leonardo F; Storch, Eric A

2014-08-01

397

Concepts and methods for describing critical phenomena in fluids  

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

398

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. PMID:21219608

2011-01-01

399

Sixth Microgravity Fluid Physics and Transport Phenomena Conference Abstracts  

NASA Technical Reports Server (NTRS)

The Sixth Microgravity Fluid Physics and Transport Phenomena Conference provides the scientific community the opportunity to view the current scope of the Microgravity Fluid Physics and Transport Phenomena Program, current research opportunities, and plans for the near future. The conference focuses not only on fundamental research but also on applications of this knowledge towards enabling future space exploration missions. A whole session dedicated to biological fluid physics shows increased emphasis that the program has placed on interdisciplinary research. The conference includes invited plenary talks, technical paper presentations, poster presentations, and exhibits. This TM is a compilation of abstracts of the papers and the posters presented at the conference. Web-based proceedings, including the charts used by the presenters, will be posted on the web shortly after the conference.

Singh, Bhim (Compiler)

2002-01-01

400

Phenomena associated with magma expansion into a drift  

SciTech Connect

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

Gaffney, E. S. (Edward S.)

2002-01-01

401

Techniques for the Study of High-Frequency Optical Phenomena  

NASA Astrophysics Data System (ADS)

Literature confirms the presence of rapid quasi periodic and periodic optical phenomena in accreting binary systems. These low intensity oscillations in the few Hz to KHz region are typically detected using fast photodiodes with the data recorded and later correlated. This paper investigates alternate real-time techniques using a low noise, high-speed photodiode and both a PC based FFT spectrum analyzer and a communications receiver for detection and analysis. Using a 14-inch Schmidt-Cassegrain telescope, detection is possible for objects of magnitude 7 or brighter over a frequency range of 10 Hz to 20 KHz where the phenomena modulation level is 1-2% or greater. Trial observations of the Sun during low activity periods indicate broad spectral components in the 50 Hz to 3 KHz range. The brief studies of the Sun and X Persei (HD 24534) indicate opportunities for future high frequency photometric investigation.

Vander Haagen, Gary A.

2008-05-01

402

The function of nonlinear phenomena in meerkat alarm calls.  

PubMed

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

Townsend, Simon W; Manser, Marta B

2011-02-23

403

Impact of large-scale atmospheric refractive structures on optical wave propagation  

NASA Astrophysics Data System (ADS)

Conventional techniques used to model optical wave propagation through the Earth's atmosphere typically as- sume flow fields based on various empirical relationships. Unfortunately, these synthetic refractive index fields do not take into account the influence of transient macroscale and mesoscale (i.e. larger than turbulent microscale) atmospheric phenomena. Nevertheless, a number of atmospheric structures that are characterized by various spatial and temporal scales exist which have the potential to significantly impact refractive index fields, thereby resulting dramatic impacts on optical wave propagation characteristics. In this paper, we analyze a subset of spatio-temporal dynamics found to strongly affect optical waves propagating through these atmospheric struc- tures. Analysis of wave propagation was performed in the geometrical optics approximation using a standard ray tracing technique. Using a numerical weather prediction (NWP) approach, we simulate multiple realistic atmospheric events (e.g., island wakes, low-level jets, etc.), and estimate the associated refractivity fields prior to performing ray tracing simulations. By coupling NWP model output with ray tracing simulations, we demon- strate the ability to quantitatively assess the potential impacts of coherent atmospheric phenomena on optical ray propagation. Our results show a strong impact of spatio-temporal characteristics of the refractive index field on optical ray trajectories. Such correlations validate the effectiveness of NWP models as they offer a more comprehensive representation of atmospheric refractivity fields compared to conventional methods based on the assumption of horizontal homogeneity.

Nunalee, Christopher G.; He, Ping; Basu, Sukanta; Vorontsov, Mikhail A.; Fiorino, Steven T.

2014-10-01

404

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

405

Possible relationships between solar activity and meteorological phenomena  

NASA Technical Reports Server (NTRS)

A symposium was conducted in which the following questions were discussed: (1) the evidence concerning possible relationships between solar activity and meteorological phenomena; (2) plausible physical mechanisms to explain these relationships; and (3) kinds of critical measurements needed to determine the nature of solar/meteorological relationships and/or the mechanisms to explain them, and which of these measurements can be accomplished best from space.

Bandeen, W. R. (editor); Maran, S. P. (editor)

1975-01-01

406

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

407

Search for Higgs and new phenomena at colliders  

SciTech Connect

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

Lammel, Stephan; /Fermilab

2006-01-01

408

Recent Applications of the Volterra Theory to Aeroelastic Phenomena  

NASA Technical Reports Server (NTRS)

The identification of nonlinear aeroelastic systems based on the Volterra theory of nonlinear systems is presented. Recent applications of the theory to problems in experimental aeroelasticity are reviewed. These results include the identification of aerodynamic impulse responses, the application of higher-order spectra (HOS) to wind-tunnel flutter data, and the identification of nonlinear aeroelastic phenomena from flight flutter test data of the Active Aeroelastic Wing (AAW) aircraft.

Silva, Walter A.; Haji, Muhammad R; Prazenica, Richard J.

2005-01-01

409

Investigation of mesoscale meteorological phenomena as observed by geostationary satellite  

NASA Technical Reports Server (NTRS)

Satellite imagery plus conventional synoptic observations were used to examine three mesoscale systems recently observed by the GOES-EAST satellite. The three systems are an arc cloud complex (ACC), mountain lee wave clouds and cloud streets parallel to the wind shear. Possible gravity-wave activity is apparent in all three cases. Of particular interest is the ACC because of its ability to interact with other mesoscale phenomena to produce or enhance convection.

Brundidge, K. C.

1982-01-01

410

Blowdown heat transfer phenomena in the scaled BWR test system  

Microsoft Academic Search

Experimental results from the Boiling Water Reactor (BWR) blowdown heat transfer program (BDHT), obtained in the BWR scaled-test apparatus, are used to provide a basis for evaluating BDHT phenomena. BWR loss-of-coolant accident (LOCA) analysis using the current BWR LOCA evaluation method, when applied to the test apparatus, shows a substantial margin in the prediction of peak cladding temperature. Observed thermal-hydraulic

G. L. Sozzi; R. J. Muzzy; G. W. Burnette

1976-01-01

411

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

412

Draft tube flow phenomena across the bulb turbine hill chart  

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

413

The hard start phenomena in hypergolic engines. Volume 1: Bibliography  

NASA Technical Reports Server (NTRS)

A bibliography of reports pertaining to the hard start phenomenon in attitude control rocket engines on Apollo spacecraft is presented. Some of the subjects discussed are; (1) combustion of hydrazine, (2) one dimensional theory of liquid fuel rocket combustion, (3) preignition phenomena in small pulsed rocket engines, (4) experimental and theoretical investigation of the fluid dynamics of rocket combustion, and (5) nonequilibrium combustion and nozzle flow in propellant performance.

Miron, Y.; Perlee, H. E.

1974-01-01

414

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

415

The role of spinning electrons in paramagnetic phenomena  

NASA Technical Reports Server (NTRS)

An attempt is made to explain paramagnetic phenomena without assuming the orientation of a molecule or ion in a magnetic field. Only the spin angular momentum is assumed to be responsible. A derivative of the Gurie-Langevin law and the magnetic moments of ions are given as a function of the number of electrons in an inner, incomplete shell. An explanation of Gerlach's experiments with iron and nickel vapors is attempted. An explanation of magnetomechanical experiments with ferromagne elements is given.

Bose, D. M.

1986-01-01

416

A multi-model approach to analysis of environmental phenomena  

Microsoft Academic Search

Abstract: This paper introduces a novel data-driven methodology named Evolutionary Polynomial Regression (EPR), which permits the multi-purpose modelling of physical phenomena, through the simultaneous solution of a number of models. Multipurpose modelling or “multi-modelling”, enables the user to make a more robust choice of those models aimed at (a) the knowledge based on data modelling, (b) on-line and offline forecasting,

O. Giustolisi; A. Doglioni; D. A. Savic; B. W. Webb

2007-01-01

417

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. PMID:22783215

Tressoldi, Patrizio E.

2012-01-01

418

Assessing Decreased Sensation and Increased Sensory Phenomena in Diabetic Polyneuropathies  

PubMed Central

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

Herrmann, David N.; Staff, Nathan P.; Dyck, P. James B.

2013-01-01

419

Superfluous Neuroscience Information Makes Explanations of Psychological Phenomena More Appealing.  

PubMed

Does the presence of irrelevant neuroscience information make explanations of psychological phenomena more appealing? Do fMRI pictures further increase that allure? To help answer these questions, 385 college students in four experiments read brief descriptions of psychological phenomena, each one accompanied by an explanation of varying quality (good vs. circular) and followed by superfluous information of various types. Ancillary measures assessed participants' analytical thinking, beliefs on dualism and free will, and admiration for different sciences. In Experiment 1, superfluous neuroscience information increased the judged quality of the argument for both good and bad explanations, whereas accompanying fMRI pictures had no impact above and beyond the neuroscience text, suggesting a bias that is conceptual rather than pictorial. Superfluous neuroscience information was more alluring than social science information (Experiment 2) and more alluring than information from prestigious "hard sciences" (Experiments 3 and 4). Analytical thinking did not protect against the neuroscience bias, nor did a belief in dualism or free will. We conclude that the "allure of neuroscience" bias is conceptual, specific to neuroscience, and not easily accounted for by the prestige of the discipline. It may stem from the lay belief that the brain is the best explanans for mental phenomena. PMID:25390208

Fernandez-Duque, Diego; Evans, Jessica; Christian, Colton; Hodges, Sara D

2014-11-12

420

The Transfer Function Model (TFM) as a Tool for Simulating Gravity Wave Phenomena in the Mesosphere  

NASA Astrophysics Data System (ADS)

The Transfer Function Model (TFM) is semi-analytical and linear, and it is designed to describe the acoustic gravity waves (GW) propagating over the globe and from the ground to 600 km under the influence of vertical temperature variations. Wave interactions with the flow are not accounted for. With an expansion in terms of frequency-dependent spherical harmonics, the time consuming vertical integration of the conservation equations is reduced to computing the transfer function (TF). (The applied lower and upper boundary conditions assure that spurious wave reflections will not occur.) The TF describes the dynamical properties of the medium divorced from the complexities of the temporal and horizontal variations of the excitation source. Given the TF, the atmospheric response to a chosen source is then obtained in short order to simulate the GW propagating through the atmosphere over the globe. In the past, this model has been applied to study auroral processes, which produce distinct wave phenomena such as: (1) standing lamb modes that propagate horizontally in the viscous medium of the thermosphere, (2) waves generated in the auroral oval that experience geometric amplification propagating to the pole where constructive interference generates secondary waves that propagate equatorward, (3) ducted modes propagating through the middle atmosphere that leak back into the thermosphere, and (4) GWs reflected from the Earth's surface that reach the thermosphere in a narrow propagation cone. Well-defined spectral features characterize these wave modes in the TF to provide analytical understanding. We propose the TFM as a tool for simulating GW in the mesosphere and in particular the features observed in Polar Mesospheric Clouds (PMC). With present-day computers, it takes less than one hour to compute the TF, so that there is virtually no practical limitation on the source configurations that can be applied and tested in the lower atmosphere. And there is no limitation on the temporal and spatial resolutions the model simulations can provide. We shall discuss the concept and organization of the TFM and present samples of GW simulations that illustrate the capabilities of the model and its user interface. We shall discuss in particular the waves that leak into the mesopause from the thermosphere above and propagate into the region from tropospheric weather systems below.

Porter, H.; Mayr, H.; Moore, J.; Wilson, S.; Armaly, A.

2008-12-01

421

Atmospheric rivers in Antarctica?  

NASA Astrophysics Data System (ADS)

Changes and variability in the surface mass balance signify one of the most puzzling questions of the present and future changes in Antarctica. In particular, understanding accumulation in the Eastern part of Antarctic continent presents a great challenge due to sparse and erratic observational network. Several previous publications reported an anomalously high precipitation in May 2009 in Dronning Maud Land, East Antarctica. This anomaly, supported by weather station data from the Princess Elisabeth station, 71°057' S, 23°021' E, 1392m asl, 173 km inland, also corresponded to anomalously high meridional moisture transport across the Southern Ocean inland. Using data from the ERA-Interim reanalysis project and a modified definition for the polar regions, May 2009 event has been classified as an atmospheric river event. Atmospheric river events, traditionally defined in the midlatitudes, are particularly strong and narrow corridors of moisture in middle atmosphere that can result in intense precipitation events once they reach the coast. May 2009 event was the first atmospheric river identified as far south as the Antarctic continent. In this study we perform a detailed analysis of the May 2009 atmospheric river event utilizing data from ERA -Interim and Weather Research and Forecasting (WRF) model simulations. We assess the role of the large-scale atmospheric circulation, particularly the role of the Zonal Wave 3 anomaly. We also investigate the synoptic-scale development of a storm that led to anomalous precipitation event in East Antarctica. We assess the role of upper and lower level forcing with the help of the quasi-geostrophic omega equation. We believe that such in-depth analysis of the dynamics of an atmospheric river event is crucial for better understanding present and future accumulation in the East Antarctica.

Tsukernik, M.; Lynch, A. H.

2013-12-01

422

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

NASA Technical Reports Server (NTRS)

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

Kostiuk, Theodor

2010-01-01

423

Atmospherics at HiRes  

Microsoft Academic Search

The High Resolution Fly's Eye observatory (HiRes) uses the atmosphere as a calorimeter. Understanding the properties of this calorimeter, primarily the atmospheric transmission, is critical to the reconstruction of air showers from the light observed at the detectors. HiRes uses lasers to probe the atmosphere while the detectors are operating. Atmospheric corrections are derived from measured light profiles of the

K. Martens; L. Wiencke

2003-01-01

424

PASCAL - Planetary Atmospheres Spectral Catalog  

Microsoft Academic Search

Spectroscopic observation of planetary atmospheres, stellar atmospheres, comets, and the interstellar medium is the most powerful tool for extracting detailed information concerning the properties of these objects. The HITRAN molecular spectroscopic database1 has traditionally served researchers involved with terrestrial atmospheric problems, such as remote-sensing of constituents in the atmosphere, pollution monitoring at the surface, identification of sources seen through the

Laurence Rothman; Iouli Gordon

2010-01-01

425

Atmospheric degradation and corrosion control  

SciTech Connect

This book offers solutions to the problems associated with atmospheric corrosion by covering corrosion theory, the mechanisms and effects of corrosion on specific materials, and the means of protecting materials against atmospheric corrosion. The book addresses the atmospheric corrosion of metals and alloys, metallic coatings, conversion coatings, polymeric coatings, plastics, elastomers, masonry materials, ceramics, wood, and indoor atmospheric corrosion.

Schweitzer, P.A.

1999-07-01

426

Global Reference Atmosphere Model (GRAM)  

NASA Technical Reports Server (NTRS)

GRAM series of four-dimensional atmospheric model validated by years of data. GRAM program, still available. More current are Gram 86, which includes atmospheric data from 1986 and runs on DEC VAX, and GRAM 88, which runs on IBM 3084. Program generates altitude profiles of atmospheric parameters along any simulated trajectory through atmosphere, and also useful for global circulation and diffusion studies.

Woodrum, A. W.

1989-01-01

427

Secondary Cosmic Ray Particles Due to GCR Interactions in the Earth's Atmosphere  

SciTech Connect

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

Battistoni, G.; /Milan U. /INFN, Milan; Cerutti, F.; /CERN; Fasso, A.; /SLAC; Ferrari, A.; /CERN; Garzelli, M.V.; /Milan U. /INFN, Milan; Lantz, M.; /Goteborg, ITP; Muraro, S. /Milan U. /INFN, Milan; Pinsky, L.S.; /Houston U.; Ranft, J.; /Siegen U.; Roesler, S.; /CERN; Sala, P.R.; /Milan U. /INFN, Milan; ,

2009-06-16

428

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

SciTech Connect

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

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

2008-01-24

429

Secondary Cosmic Ray particles due to GCR interactions in the Earth's atmosphere  

E-print Network

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

G. Battistoni; F. Cerutti; A. Fassò; A. Ferrari; M. V. Garzelli; M. Lantz; S. Muraro; L. S. Pinsky; J. Ranft; S. Roesler; P. R. Sala

2007-11-13

430

Fundamentals of Atmospheric Radiation  

NASA Astrophysics Data System (ADS)

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

Bohren, Craig F.; Clothiaux, Eugene E.

2006-02-01

431

Pluto's Increasing Atmospheric Pressure  

NASA Astrophysics Data System (ADS)

In 2007, the occultation of a V=13.2 magnitude star was successfully observed from Mt. John Observatory, Mt. Canopus Observatory and our 14-inch Meade portable system in Musselroe Bay, New Zealand. We simultaneously fit an isothermal model atmosphere (Eliot and Young, 1992) to the main drop and recovery of the observed occultation light curves to derive global atmospheric parameters and a geometric solution. The data is well fit by a spherical atmospheric model with no need to fit for an oblate profile. The isothermal atmospheric solution gives a temperature of 112 ± 1 K and a pressure of 2.4 ± 0.1 microbar at a radius of 1275 km. This is an increase in temperature of 8 K and a 28% increase in pressure at our reference radius over 13 months (the previous stellar occultation was in June 2006, Young et al. 2008) with no significant change in half-light radius. Due to the increase in temperature and hence scale height, we expect the surface pressure did not increase as dramatically. The sensitivity of atmospheric pressure to changes in isothermal temperature will be discussed. This work was supported by NASA planetary astronomy grant NNG05GF05G and NSF major research instrumentation grant AST0321338.

Olkin, Catherine B.; Young, L.; Young, E.; Buie, M.; French, R.; Howell, R.; Regester, J.; Ruhland, C.

2009-09-01

432

LIMITS ON QUAOAR'S ATMOSPHERE  

SciTech Connect

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

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

2013-09-10

433

Atmospheric Laser Communication.  

NASA Astrophysics Data System (ADS)

Atmospheric laser communication, often referred to as free-space optics (FSO) or free-space laser (FSL) communication, is similar to fiber optic cable in terms of carrier wavelength and bandwidth capability, but data are transmitted directly through the atmosphere via laser beams over paths from a few meters to 4 km or longer. FSL uses lasers in the near-infrared spectrum, typically at wavelengths of 850 or 1550 nm. Given these wavelengths, atmospheric attenuation must be considered, and an adequate margin of optical power (dB) must exist to support high system availability (the percentage of time that an FSL link is in operation, typically 99.9%). A visual range of 100 m can attenuate a laser beam at a rate of nearly 130 dB km-1. For short links (< 1200 m), fog and low clouds are the primary concerns. For longer links, scintillation, heavy rain, and snow frequently become issues. To address these issues, long-term climate data are analyzed to determine the frequency of occurrence of low visibilities and low-cloud ceilings. To estimate availability at a site of interest, adjustments to airport climate data are made to accommodate differences in altitude, geography, and the effects of the urban heat island. In sum, communication via FSL is a feasible alternative to fiber optic cable when atmospheric conditions are considered and properly analyzed.(Current affiliation: The Boeing Company, Seattle, Washington+Current affiliation: Department of Atmospheric Sciences, University of Washington, Seattle, Washington

Fischer(, Kenneth W.; Witiw, Michael R.; Baars+, Jeffrey A.; Oke, T. R.

2004-05-01

434

ICOS Atmospheric Thematic Center  

NASA Astrophysics Data System (ADS)

ICOS is a recently-launched, world-class research infrastructure dedicated to the monitoring and improved understanding of carbon sources and sinks. It consists of complementary, harmonized networks of long-term ecosystem monitoring stations focusing on Europe and adjacent regions. The ICOS networks will comprise about 40 operational atmospheric stations (measuring atmospheric composition in greenhouse gases and other core parameters), 30 ecosystem stations (measuring fluxes from ecosystems) and about 10 oceanic measurement platforms. The networks will be coordinated through a set of central facilities: three Thematic centres respectively for atmospheric, ecosystem and ocean data, and a Central analytical lab. The mission of the thematic centres are to process, validate and distribute data to end-users. ICOS will also set up a Carbon portal dedicated to easy discovery of and access to data and elaborated products such as flux maps by end users.The Atmospheric Thematic Center (ATC) has three main functions: Operate the atmospheric data processing chains, going from data transmission from stations to the routine delivery of quality checked data-stream Carry out regular measurement technology survey, analysis and enable development of new sensors and their testing Monitor the network and propose spare instruments, training, and technical assistance.

Rivier, Leonard; Hazan, Lynn; Tarniewicz, Jerome; Laurent, Olivier; Yver, Camille; Laurila, Tuomas; Paris, Jean-Daniel; Ramonet, Michel; Ciais, Philippe

2014-05-01

435

Infrared laboratory studies of synthetic planetary atmospheres  

NASA Technical Reports Server (NTRS)

The initial stages of the research were involved with a test of Burch's law of multiplicative transmittance for mixed absorbing gases when their lines are broadened by H2 and He, which are constituents of the atmospheres of the major planets. The broadening of individual lines in the CO fundamental by various gases was investigated. Line strength and half-width for individual CO lines were studied as a function of temperature. Measurements of total band absorptance as a function of absorber thickness and total effective pressure were made at various temperatures for bands of CO and N2O. Attempts were made to develop a phenomenological theory of line broadening that would account for the phenomena observed for the CO fundamental and those reported for more highly polar gases. Laboratory measurements of nitric acid vapor absorptance were compared with balloon measurements in arriving at an estimate of the quantity of nitric acid vapor present in the earth's atmosphere in the region of the ozone layer.

Williams, D.

1972-01-01

436

Biosphere/atmosphere Interactions  

NASA Technical Reports Server (NTRS)

Vegetation influences the energy, mass and momentum exchange between land-surface and atmosphere and, in that way, may significantly affect weather and climate. The morphology and physiology of the vegetation determine the surface albedo, precipitation interception and interception loss, stomatal control of transpiration, moisture storage in the root zone and, through the vegetation roughness height, the aerodynamic resistance to the transfers of latent and sensible heat and momentum between land-surface and atmosphere. That the albedo and soil moisture have a large influence on the atmospheric circulation and rainfall was demonstrated in sensitivity experiments with general circulation models. Moreover, through its effect on the convergence of the horizontal water vapor transport in the planetary boundary layer, the surface roughness height has a large influence on rainfall.

Mintz, Y.

1984-01-01

437

Atmospheres of brown dwarfs  

NASA Astrophysics Data System (ADS)

Brown dwarfs are the coolest class of stellar objects known to date. Our present perception is that brown dwarfs follow the principles of star formation, and that brown dwarfs share many characteristics with planets. Being the darkest and lowest mass stars known makes brown dwarfs also the coolest stars known. This has profound implication for their spectral fingerprints. Brown dwarfs cover a range of effective temperatures which cause brown dwarfs atmospheres to be a sequence that gradually changes from a M-dwarf-like spectrum into a planet-like spectrum. This further implies that below an effective temperature of 2,800 K, clouds form already in atmospheres of objects marking the boundary between M-Dwarfs and brown dwarfs. Recent developments have sparked the interest in plasma processes in such very cool atmospheres: sporadic and quiescent radio emission has been observed in combination with decaying X-ray activity indicators across the fully convective boundary.

Helling, Christiane; Casewell, Sarah

2014-11-01

438

Atmospheric engineering of Mars  

NASA Technical Reports Server (NTRS)

The feasibility of creating a breathable atmosphere on Mars was studied. Assuming that indigenous life is absent, and that human habitation will prove economically justifiable, several methods of introducing oxygen were considered. On the basis of energy requirements, photosynthetic oxygen production appears to be reasonable, assuming that the amounts of water, carbon dioxide, and mineral nutrients available on the Martian surface would be adequate for the growth of photosynthetic microorganisms. However, optimum rates of O2 formation could occur only after a significant increase in average temperature and in atmospheric mass. The generation of a runaway greenhouse/advective effect was considered. However, neither the energy requirement nor the time constant for initiation could be calculated. There appear to be no insuperable obstacles to the conversion of the Martian atmosphere to one containing oxygen, but the conversion would require many thousands of years.

Macelroy, R. D.; Averner, M. M.

1976-01-01

439

Atmospheric refraction: a history.  

PubMed

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

Lehn, Waldemar H; van der Werf, Siebren

2005-09-20

440

The Atmosphere of Mars  

NSDL National Science Digital Library

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

Roberta Johnson

2000-07-01

441

Airborne atmospheric sampling system  

NASA Technical Reports Server (NTRS)

The atmospheric sampling system developed for use on board commercial airliners as part of the Global Atmospheric Sampling Program (GASP) is described. The automated air-constituent measuring system is installed in a Boeing 747 airliner below the passenger cabin floor near the nose wheel well. It consists of an air sample flow system, composed of air inlet and pressurization systems, computerized data acquisition and system control units which direct system operation in 15 modes, and commercial instruments significantly modified to measure low levels of atmospheric constituents (ozone, water vapor, nitrogen oxides, carbon monoxide, chlorofluoromethanes, particulates, condensation nuclei, sulfates and nitrates). Flight and meteorological data, including air temperature and altitude, are also recorded. The system is designed for servicing at 14-day intervals, and to require a minimum of aircrew involvement.

Gustafsson, U. R. C.; Perkins, P. J.; Nyland, T. W.; Tiefermann, M. W.; Dudzinski, T. J.

1979-01-01

442

Dissipation in Planetary Atmospheres  

NASA Astrophysics Data System (ADS)

The net radiative entropy flux of a planet is negative because atmospheres absorb solar radiation at a higher temperature than the temperature at which they re-emit an equal amount of longwave radiation to space. If in the long term the entropy of an atmosphere is constant, the radiative entropy loss must be balanced by the entropy production associated with thermally direct heat transports and dissipation. Given estimates of the thermally direct sources of entropy production and the temperature at which dissipation occurs, this determines the rate of dissipation in an atmosphere. It is estimated that the entropy production due to dissipation in the atmospheres of Venus, Earth, Mars and Titan occurs at the rate, respectively, of about ?23, 29, 2, and ?4 mW m-2 K-1. If the dissipation in Earth’s atmosphere occurs between temperatures of 250 K and 288 K the dissipation rate must lie between 7.3 and 8.4 W m- 2, consistent with other recent estimates. The terrestrial heat engine operates with an efficiency of about 60% of the Carnot efficiency. Sources of dissipation in planetary atmospheres are highly uncertain, even for Earth. For Earth, frictional dissipation in rainfall is comparable to the turbulent dissipation of kinetic energy. Rainfall might also be a significant source of dissipation on Titan but it is not likely to be important for Mars or Venus. The breaking of upward propagating internal gravity waves generated by convection and flow over the surface topography is another source of dissipation and is possibly dominant on Venus.

Schubert, Gerald; Mitchell, J.

2012-10-01

443

Photochemistry of Pluto's Atmosphere  

NASA Technical Reports Server (NTRS)

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

Krasnopolsky, Vladimir A.

1999-01-01

444

Mars Climate Orbiter's Investigation of the Atmosphere and Polar Caps  

NASA Technical Reports Server (NTRS)

The Mars Climate Orbiter (MCO) is now on its way to Mars. It carries an atmospheric sounder whose observations will provide a continuous, global data set on weather and climate for a full Martian year. This paper describes the observation strategy and anticipated results from the Pressure Modulator Infrared Radiometer (PMIRR). PMIRR will measure vertical profiles of atmospheric infrared radiance in the 7 to 50 micron wavelength region extending from the surface of Mars to 80-km altitude. The observations have a vertical resolution of 5 km, or one-half the atmospheric scale height. From these radiance profiles we will retrieve profiles of atmospheric temperature, pressure, and the amounts of dust, condensates and water vapor. In addition, PMIRR will measure the radiative balance of the polar regions of Mars in an effort to better understand the short-term climate variability of the planet. The information obtained with PMIRR on MCO will be complementary to data obtained by the Thermal Emission Spectrometer (TES) and Radio Science (RS) experiments on the Mars Global Surveyor. A major emphasis of our research will be the assimilation of PMIRR data into numerical models of the Martian atmosphere. Assimilation schemes, of which several are currently in development, will permit the extension of measurements to spatial and temporal scales and to phenomena (e.g. winds) not observed directly by PMIRR.

McCleese, D. J.; Moroz, V.; Schofield, T.; Taylor, F.; Zurek, R.

1999-01-01

445

An atmospheric alternative  

NASA Astrophysics Data System (ADS)

A common goal of world governments is to reduce the anthropogenic effect on the global atmosphere within the next 100 to 200 years. But there may be more than one path to that goal, according to three scientists who offered an alternative to the current timetable recommendations of the Intergovernmental Panel on Climate Change and other United Nations panels.Current proposals from the IPCC recommend immediate and sizable reductions in carbon-dioxide emissions and a relatively rapid transition away from fossil fuels in order to gradually stabilize atmospheric CO2 concentrations by 2150.

446

Atmospheric and Oceanic Modeling  

NSDL National Science Digital Library

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

Adcroft, Alistair; Emanuel, Kerry A., 1955-; Marshall, John

2007-04-07

447

Procedure for Prioritization of Natural Phenomena Hazards Evaluations for Existing DOE Facilities  

SciTech Connect

This document describes the procedure to be used for the prioritization for natural phenomena hazards evaluations of existing DOE facilities in conformance with DOE Order 5480.28, `Natural Phenomena Hazards Mitigation.`

Conrads, T.J., Westinghouse Hanford

1996-05-07

448

LANDSLIDE PHENOMENA IN SEVAN NATIONAL PARK -ARMENIA Andon Dimitrov Lazarov(1)  

E-print Network

LANDSLIDE PHENOMENA IN SEVAN NATIONAL PARK - ARMENIA Andon Dimitrov Lazarov(1) , Dimitar Minchev(2 landslides phenomena in Sevan National Park ­ Republic Armenia. For this purpose Identification Deformation, deformation (volcanoes, earthquakes, and landslides), glacier studies, vegetation growth etc. With increase

Mustakerov, Ivan

449

Dynamic phenomena and quality defects in laser cutting  

NASA Astrophysics Data System (ADS)

Laser cutting of sheet metals is used all over the world by production companies since it combines high speed, excellent quality and economic advantages. Nevertheless certain limits exist for materials thickness and speed and also to quality of the cut edges that show eventually strong roughness and adherent material as dross and slag. In order to extend these limits and to approve especially cutting speed and quality of the cut edges the mechanism of laser cutting must be fully understood. As far as it concerns steady state cutting the phenomena contributed to the process with a thin liquid layer covering the momentary end of the cut kerf that serves for absorption of laser radiation and also for generation of reaction heat also for melting of the solid material and finally for the ejection of liquid material at the bottom of the work piece due to the friction with the process gas have been clarified a long time before. Also dynamic phenomena associated to reaction and to waves on the surface of the liquid body that all lead to a certain roughness have been described in the past. Nevertheless the phenomena taking place inside the liquid layer are not fully understood especially the influence of surface tension that is much higher than the pressure in the melt and would in principal inhibit any ejection of melt that is necessary for cutting. Therefore the authors carried out an analysis of the processes taking place in the liquid body that leads to a picture with a discontinuous ejection of melt and explains the formation of a rough surface structure and also of adherent material for the case of a rather thick workpiece (> 10mm).

Schuöcker, Dieter; Schuöcker, Georg

2012-07-01

450

Modelling transport phenomena in a multi-physics context  

NASA Astrophysics Data System (ADS)

Innovative heating research on cooking, pasteurization/sterilization, defrosting, thawing and drying, often focuses on areas which include the assessment of processing time, evaluation of heating uniformity, studying the impact on quality attributes of the final product as well as considering the energy efficiency of these heating processes. During the last twenty years, so-called electro-heating-processes (radio-frequency - RF, microwaves - MW and ohmic - OH) gained a wide interest in industrial food processing and many applications using the above mentioned technologies have been developed with the aim of reducing processing time, improving process efficiency and, in many cases, the heating uniformity. In the area of innovative heating, electro-heating accounts for a considerable portion of both the scientific literature and commercial applications, which can be subdivided into either direct electro-heating (as in the case of OH heating) where electrical current is applied directly to the food or indirect electro-heating (e.g. MW and RF heating) where the electrical energy is firstly converted to electromagnetic radiation which subsequently generates heat within a product. New software packages, which make easier solution of PDEs based mathematical models, and new computers, capable of larger RAM and more efficient CPU performances, allowed an increasing interest about modelling transport phenomena in systems and processes - as the ones encountered in food processing - that can be complex in terms of geometry, composition, boundary conditions but also - as in the case of electro-heating assisted applications - in terms of interaction with other physical phenomena such as displacement of electric or magnetic field. This paper deals with the description of approaches used in modelling transport phenomena in a multi-physics context such as RF, MW and OH assisted heating.

Marra, Francesco

2015-01-01

451

The Fragility of Interdependency: Coupled Networks Switching Phenomena  

NASA Astrophysics Data System (ADS)

Recent disasters ranging from abrupt financial ``flash crashes'' and large-scale power outages to sudden death among the elderly dramatically exemplify the fact that the most dangerous vulnerability is hiding in the many interdependencies among different networks. In the past year, we have quantified failures in model of interconnected networks, and demonstrated the need to consider mutually dependent network properties in designing resilient systems. Specifically, we have uncovered new laws governing the nature of switching phenomena in coupled networks, and found that phenomena that are continuous ``second order'' phase transitions in isolated networks become discontinuous abrupt ``first order'' transitions in interdependent networks [S. V. Buldyrev, R. Parshani, G. Paul, H. E. Stanley, and S. Havlin, ``Catastrophic Cascade of Failures in Interdependent Networks,'' Nature 464, 1025 (2010); J. Gao, S. V. Buldyrev, H. E. Stanley, and S. Havlin, ``Novel Behavior of Networks Formed from Interdependent Networks,'' Nature Physics 8, 40 (2012). We conclude by discussing the network basis for understanding sudden death in the elderly, and the possibility that financial ``flash crashes'' are not unlike the catastrophic first-order failure incidents occurring in coupled networks. Specifically, we study the coupled networks that are responsible for financial fluctuations. It appears that ``trend switching phenomena'' that we uncover are remarkably independent of the scale over which they are analyzed. For example, we find that the same laws governing the formation and bursting of the largest financial bubbles also govern the tiniest finance bubbles, over a factor of 1,000,000,000 in time scale [T. Preis, J. Schneider, and H. E. Stanley, ``Switching Processes in Financial Markets,'' Proc. Natl. Acad. Sci. USA 108, 7674 (2011); T. Preis and H. E. Stanley, ``Bubble Trouble: Can a Law Describe Bubbles and Crashes in Financial Markets?'' Physics World 24, No. 5, 29 (May 2011)].

Stanley, H. Eugene

2013-03-01

452

Space Commercial Opportunities for Fluid Physics and Transport Phenomena Applications  

NASA Technical Reports Server (NTRS)

Microgravity research at NASA has been an undertaking that has included both science and commercial approaches since the late 80s and early 90s. The Fluid Physics and Transport Phenomena community has been developed, through NASA's science grants, into a valuable base of expertise in microgravity science. This was achieved through both ground and flight scientific research. Commercial microgravity research has been primarily promoted thorough NASA sponsored Centers for Space Commercialization which develop cost sharing partnerships with industry. As an example, the Center for Advanced Microgravity Materials Processing (CAMMP)at Northeastern University has been working with cost sharing industry partners in developing Zeolites and zeo-type materials as an efficient storage medium for hydrogen fuel. Greater commercial interest is emerging. The U.S. Congress has passed the Commercial Space Act of 1998 to encourage the development of a commercial space industry in the United States. The Act has provisions for the commercialization of the International Space Station (ISS). Increased efforts have been made by NASA to enable industrial ventures on-board the ISS. A Web site has been established at http://commercial/nasa/gov which includes two important special announcements. One is an open request for entrepreneurial offers related to the commercial development and use of the ISS. The second is a price structure and schedule for U.S. resources and accommodations. The purpose of the presentation is to make the Fluid Physics and Transport Phenomena community, which understands the importance of microgravity experimentation, aware of important aspects of ISS commercial development. It is a desire that this awareness will be translated into a recognition of Fluid Physics and Transport Phenomena application opportunities coordinated through the broad contacts of this community with industry.

Gavert, R.

2000-01-01

453

Survey of literature on convective heat transfer coefficients and recovery factors for high atmosphere thermometry  

NASA Technical Reports Server (NTRS)

Heat transfer phenomena of rarefied gas flows is discussed based on a literature survey of analytical and experimental rarefied gas dynamics. Subsonic flows are emphasized for the purposes of meteorological thermometry in the high atmosphere. The heat transfer coefficients for three basic geometries are given in the regimes of free molecular flow, transition flow, slip flow, and continuum flow. Different types of heat phenomena, and the analysis of theoretical and experimental data are presented. The uncertainties calculated from the interpolation rule compared with the available experimental data are discussed. The recovery factor for each geometry in subsonic rarefied flows is also given.

Chung, S.

1973-01-01

454

Thermomagnetic phenomena in the mixed state of high temperature superconductors  

NASA Technical Reports Server (NTRS)

Galvano- and thermomagnetic-phenomena in high temperature superconductors, based on kinetic coefficients, are discussed, along with a connection between the electric field and the heat flow in superconductor mixed state. The relationship that determines the transport coefficients of high temperature superconductors in the mixed state based on Seebeck and Nernst effects is developed. It is shown that this relationship is true for a whole transition region of the resistive mixed state of a superconductor. Peltier, Ettingshausen and Righi-Leduc effects associated with heat conductivity as related to high temperature superconductors are also addressed.

Meilikhov, E. Z.

1995-01-01

455

Transport phenomena in the asymmetric quantum multibaker map  

NASA Astrophysics Data System (ADS)

By studying a modified (unbiased) quantum multibaker map, we were able to obtain a finite asymptotic quantum current without a classical analog. This result suggests a general method for the design of purely quantum ratchets and sheds light on the investigation of the mechanisms leading to net transport generation by breaking symmetries of quantum systems. Moreover, we propose the multibaker map as a resource to study directed transport phenomena in chaotic systems without bias. In fact, this is a paradigmatic model in classical and quantum chaos, but also in statistical mechanics.

Ermann, Leonardo; Carlo, Gabriel G.; Saraceno, Marcos

2008-01-01

456

Modeling of Multiscale and Multiphase Phenomena in Materials Processing  

NASA Astrophysics Data System (ADS)

In order to demonstrate how CFD can help scientists and engineers to better understand the fundamentals of engineering processes, a number of examples are shown and discussed. The paper covers (i) special aspects of continuous casting of steel including turbulence, motion and entrapment of non-metallic inclusions, and impact of soft reduction; (ii) multiple flow phenomena and multiscale aspects during casting of large ingots including flow-induced columnar-to-equiaxed transition and 3D formation of channel segregation; (iii) multiphase magneto-hydrodynamics during electro-slag remelting; and (iv) melt flow and solidification of thin but large centrifugal castings.

Ludwig, Andreas; Kharicha, Abdellah; Wu, Menghuai

2013-03-01

457

Cathode phenomena in a low power, steady state MPD thruster  

NASA Technical Reports Server (NTRS)

Mass loss and surface temperature measurements, filter photography and SEM surface characterization are used to study cathode phenomena in a steady state self-field MPD thruster operated at power levels between 15 and 30 kW. The equilibrium cathode temperature is found to be approximately 3200 K over most of its length, for which evaporation and thermionic emission adequately explain measured erosion rates and current levels. The start-up phase is characterized by spot current attachment with associated high erosion rates.

Kelly, A. J.; Jahn, R. G.; Myers, R. M.; Suzuki, N.

1988-01-01

458

Analyzing simple pendulum phenomena with a smartphone acceleration sensor  

NASA Astrophysics Data System (ADS)

This paper describes a further experiment using the acceleration sensor of a smartphone. For a previous column on this topic, including the description of the operation and use of the acceleration sensor, see Ref. 1. In this contribution we focus on analyzing simple pendulum phenomena. A smartphone is used as a pendulum bob, and SPARKvue2 software is used in conjunction with an iPhone or an iPod touch, or the Accelogger3 app for an Android device. As described in Ref. 1, the values measured by the smartphone are subsequently exported to a spreadsheet application (e.g., MS Excel) for analysis.

Vogt, Patrik; Kuhn, Jochen

2012-10-01

459

Quantum Simulator for Transport Phenomena in Fluid Flows  

E-print Network

Transport phenomena are one of the most challenging problems in computational physics. We present a quantum simulator based on pseudospin-boson quantum systems, which is suitable for encoding fluid dynamics problems within a lattice kinetic formalism. This quantum simulator is obtained by exploiting the analogies between Dirac and lattice Boltzmann equations. It is shown that both the streaming and collision processes of lattice Boltzmann dynamics can be implemented with controlled quantum operations, using a heralded quantum protocol to encode non-unitary scattering processes. The proposed simulator is amenable to realization in controlled quantum platforms, such as ion-trap quantum computers or circuit quantum electrodynamics processors.

Mezzacapo, A; Lamata, L; Egusquiza, I L; Succi, S; Solano, E

2015-01-01

460

Damping phenomena in a wire rope vibration isolation system  

NASA Technical Reports Server (NTRS)

A study of the dynamic characteristics of a wire rope vibration isolation system constructed with helical isolators is presented. Emphasis is placed on the analytical modeling of damping mechanisms in the system. An experimental investigation is described in which the static stiffness curve, hysteresis curves, phase trajectories, and frequency response curves were obtained. A semi-empirical model having nonlinear stiffness, nth-power velocity damping, and variable Coulomb friction damping is developed and results are compared to experimental data. Conclusions about dynamic phenomena in the wire rope system are made based on the experimental and semi-empirical results.

Tinker, Michael L.; Cutchins, Malcolm A.

1990-01-01