WorldWideScience

Sample records for artificial radiation belts

  1. Control of the energetic proton flux in the inner radiation belt by artificial means

    Science.gov (United States)

    Shao, X.; Papadopoulos, K.; Sharma, A. S.

    2009-07-01

    Earth's inner radiation belt located inside L = 2 is dominated by a relatively stable flux of trapped protons with energy from a few to over 100 MeV. Radiation effects in spacecraft electronics caused by the inner radiation belt protons are the major cause of performance anomalies and lifetime of Low Earth Orbit satellites. For electronic components with large feature size, of the order of a micron, anomalies occur mainly when crossing the South Atlantic Anomaly. However, current and future commercial electronic systems are incorporating components with submicron size features. Such systems cannot function in the presence of the trapped 30-100 MeV protons, as hardening against such high-energy protons is essentially impractical. The paper discusses the basic physics of the interaction of high-energy protons with low-frequency Shear Alfven Wave (SAW) under conditions prevailing in the radiation belts. Such waves are observed mainly in the outer belt, and it is believed that they are excited by an Alfven Ion Cyclotron instability driven by anisotropic equatorially trapped energetic protons. The paper derives the bounce and drift-averaged diffusion coefficients and uses them to determine the proton lifetime as a function of the spectrum and amplitude of the volume-averaged SAW resonant with the trapped energetic protons. The theory is applied to the outer and inner radiation belts. It is found that the resonant interaction of observed SAW with nT amplitude in the outer belt results in low flux of trapped protons by restricting their lifetime to periods shorter than days. A similar analysis for the inner radiation belt indicates that broadband SAW in the 1-10 Hz frequency range and average amplitude of 25 pT would reduce the trapped energetic proton flux by more than an order of magnitude within 2 to 3 years. In the absence of naturally occurring SAW waves, such reduction can be achieved by injecting such waves from ground-based transmitters. The analysis indicates

  2. Measurements of the artificially stimulated precipitation of electrons from the inner radiation belt in the experiment 'Spolokh-2'

    Science.gov (United States)

    Zhulin, I. A.; Kostin, V. M.; Pimenov, I. A.; Ruzhin, Iu. Ia.; Skomarovskii, V. S.; Zhuchenko, Iu. M.; Romanovskii, Iu. A.

    Artificial ionospheric disturbances, resulting from a barium shaped charge release from Spolokh-2 rocket payload, launched on June 29, 1978, are described. Geiger counters were used to detect the stimulated fluxes of the precipitated electrons with energies greater than 40 keV. The spectral analysis of the counter data was used to find the short- and long-term charges of the electron fluxes after the charge explosion. Artificial precipitation of electrons was observed more than 100 s after the explosion.

  3. Measurements of the artificially stimulated precipitation of electrons from the inner radiation belt in the experiment 'Spolokh-2'

    International Nuclear Information System (INIS)

    Artificial ionospheric disturbances, resulting from a barium shaped charge release from Spolokh-2 rocket payload, launched on June 29, 1978, are described. Geiger counters were used to detect the stimulated fluxes of the precipitated electrons with energies greater than 40 keV. The spectral analysis of the counter data was used to find the short- and long-term charges of the electron fluxes after the charge explosion. Artificial precipitation of electrons was observed more than 100 s after the explosion

  4. Data From HANE-Generated Radiation Belts and the Origin of Diffusion Theory

    Energy Technology Data Exchange (ETDEWEB)

    Winske, Dan [Los Alamos National Laboratory

    2012-07-16

    In this presentation we briefly review some of the published data regarding the artificial radiation belts produced by the Starfish and R2 high altitude nuclear explosions in 1962. The data showed slow temporal variations of the belts in altitude (L) and pitch angle ({alpha}) that could be modeled as a diffusion process. That early work formed the basis for more complex radiation belt diffusion models that are in use at present.

  5. The Foundations of Radiation Belt Research

    Science.gov (United States)

    Ludwig, G. H.

    2008-12-01

    The United States undertook the launching of an artificial Earth satellite as part of its contribution to the International Geophysical Year. The Vanguard program was established to meet that commitment, and it developed a launch vehicle, ground station network, and suite of scientific payloads, including the cosmic ray experiment proposed by James A. Van Allen. Although Vanguard eventually exceeded all of its pre-stated goals, the preemptive launches of Sputniks I and II by the Soviets in October and November 1957 spurred the U.S. into a frenzy of activity, resulting in the launches of Explorers I and III in January and March of 1958. The data from those two satellites quickly revealed the lower boundary of an unexpected region of high intensity radiation trapped in the Earth's magnetic field. The original announcement in May 1958 stated that the radiation was probably composed of either protons or electrons, and that, if electrons, it was probably bremsstrahlung formed in the satellite shell. Immediately following that announcement, approval was received for what became Explorer IV, whose announced purpose was to follow up on the new discovery. Another reason for the satellite, unmentioned at the time, was its inclusion as a component of the highly classified Argos program, a covert military program to test whether the detonation of nuclear devices at high altitude would inject measurable numbers of charged particles into durable trajectories in the Earth's magnetic field. Our team at Iowa produced the satellites under the oversight of, and with assistance by, the Army Ballistic Missile Agency in Huntsville, and with the contributions of key hardware from several other government laboratories. The project was completed in the unbelievably short period of seventy-seven days from approval to launch. Launched into a higher-inclination orbit than the earlier Explorers, Explorer IV confirmed the discovery and greatly expanded our understanding of the natural

  6. Imaging Jupiter Radiation Belts At Low Frequencies

    Science.gov (United States)

    Girard, J. N.; de Pater, I.; Zarka, P.; Santos-Costa, D.; Sault, R.; Hess, S.; Cecconi, B.; Fender, R.; Pewg, Lofar

    2014-04-01

    The ultra-relativistic electrons, trapped in the inner radiation belts of Jupiter, generates a strong synchrotron radio emission (historically known as the jovian decimeter radiation (DIM)) which is beamed, polarized (~20% linear, ~1% circular) and broadband. It has been extensively observed by radio telescopes/ probes and imaged by radio interferometers over a wide frequency spectrum (from >300 MHz up to 22 GHz). This extended emission presents two main emission peaks constantly located on both sides of the planet close to the magnetic plane. High latitude emissions were also regularly observed at particular frequencies, times and in particular observational configurations. This region of the magnetosphere is "frozen" due to the strong magnetic field (~4.2 G as the equator) and therefore is forced to rotate at the planetary period (T≈9h55m). Due to the tilt (~ 10o) between the spin axis of the planet and the magnetic axis (which can be seen as dipolar in first approximation), the belts and the associated radio emission wobble around the planet center. The analysis of the flux at different frequencies highlighted spatial, temporal and spectral variabilities which origins are now partly understood. The emission varies at different time scales (short-time variations of hours to long-term variation over decades) due to the combination of visibility effect (wobbling, beaming, position of the observer in the magnetic rotating reference frame) [1], [2] and intrinsic local variations (interaction between relativistic electrons and satellites/dust, delayed effect of the solar wind ram pressure, impacts events) [3], [4], [5]. A complete framework is necessary to fully understand the source, loss and transport processes of the electrons originating from outside the belt, migrating by inward diffusion and populating the inner region of the magnetosphere. Only a few and unresolved measurements were made below 300 MHz and the nonsystematic observation of this radio emission

  7. Ionic composition of the earth's radiation belts

    Science.gov (United States)

    Spjeldvik, W. N.

    1983-01-01

    Several different ion species have been positively identified in the earth's radiation belts. Besides protons, there are substantial fluxes of helium, carbon and oxygen ions, and there are measurable quantities of even heavier ions. European, American and Soviet space experimenters have reported ion composition measurements over wide ranges of energies: at tens of keV (ring-current energies) and below, and at hundreds of keV and above. There is still a gap in the energy coverage from several tens to several hundreds of keV where little observational data are available. In this review emphasis is placed on the radiation belt ionic structure above 100 keV. Both quiet time conditions and geomagnetic storm periods are considered, and comparison of the available space observations is made with theoretical analysis of geomagnetically trapped ion spatial, energy and charge state distributions.

  8. The atmospheric implications of radiation belt remediation

    Directory of Open Access Journals (Sweden)

    C. J. Rodger

    2006-08-01

    Full Text Available High altitude nuclear explosions (HANEs and geomagnetic storms can produce large scale injections of relativistic particles into the inner radiation belts. It is recognised that these large increases in >1 MeV trapped electron fluxes can shorten the operational lifetime of low Earth orbiting satellites, threatening a large, valuable population. Therefore, studies are being undertaken to bring about practical human control of the radiation belts, termed "Radiation Belt Remediation" (RBR. Here we consider the upper atmospheric consequences of an RBR system operating over either 1 or 10 days. The RBR-forced neutral chemistry changes, leading to NOx enhancements and Ox depletions, are significant during the timescale of the precipitation but are generally not long-lasting. The magnitudes, time-scales, and altitudes of these changes are no more significant than those observed during large solar proton events. In contrast, RBR-operation will lead to unusually intense HF blackouts for about the first half of the operation time, producing large scale disruptions to radio communication and navigation systems. While the neutral atmosphere changes are not particularly important, HF disruptions could be an important area for policy makers to consider, particularly for the remediation of natural injections.

  9. Space electronics: radiation belts set new challenges

    International Nuclear Information System (INIS)

    Telecommunications satellites have been in use since 1962 with the first satellite network (constellation) coming into operation in 1966. GPS systems have been available since the mid seventies. Until now, all these systems have avoided orbits which lie within the radiation belts. The latest constellation projects, offering much wider bandwidths, need to use orbits between 1500 and 2000 km, where the proton density is at its highest. The vulnerability of future generations of components can be predicted by extrapolating the behaviour of current devices. Screening is not a viable option due to cost and weight limitations in satellite applications. As a result, satellite and component manufacturers are seeking new methods of hardening components or making them more radiation tolerant in an environment where the radiation levels are ten times those currently experiences. (authors)

  10. Radiation belts study in RESONANCE project

    Science.gov (United States)

    Mogilevsky, Mikhail; Demekhov, Andrei; Zelenyi, Lev; Petrukovich, Anatoly; Shklyar, David

    The Earth’s inner magnetosphere is an important part of space weather framework. Outer radiation belt is a home for numerous communication and navigation satellites. But besides this practical problem, this region is a theoretical nugget. Hot magnetospheric, cold plas¬mospheric, and, in contrast, high energy plasma coexist here. Such non-equilibrium state of plasma is glued by various plasma oscillations actively interacting with particles and resulting, in particular, in spatial and velocity diffusion. Diffusion influences acceleration and precipitation of particles and defines their life¬time in the Earth’s magnetosphere. The project RESONANCE is aimed to study the whole complex of these issues, both practical (space weather), and fundamental (nonlinear plasma dynamics). The project RESONANCE is a part of the Russian Federal State Program. Lavochkin Association is responsi¬ble for preparation and testing of the satellites. Space Research Institute of the Russian Academy of Sciences is a leading scientific organization. Besides Russian scientists, specialists from Austria, Bulgaria, Czech Re¬public, Finland, France, Germany, Greece, Poland, Slovakia, Ukraine, USA take part.

  11. A Physical Model of Electron Radiation Belts of Saturn

    Science.gov (United States)

    Lorenzato, L.; Sicard-Piet, A.; Bourdarie, S.

    2012-09-01

    Enrolling on the Cassini age, a physical Salammbô model for the radiation belts of Saturn have been developed including several physical processes governing the kronian magnetosphere. Results have been compared with Cassini MIMI LEMMS data.

  12. Rotationally driven 'zebra stripes' in Earth's inner radiation belt.

    Science.gov (United States)

    Ukhorskiy, A Y; Sitnov, M I; Mitchell, D G; Takahashi, K; Lanzerotti, L J; Mauk, B H

    2014-03-20

    Structured features on top of nominally smooth distributions of radiation-belt particles at Earth have been previously associated with particle acceleration and transport mechanisms powered exclusively by enhanced solar-wind activity. Although planetary rotation is considered to be important for particle acceleration at Jupiter and Saturn, the electric field produced in the inner magnetosphere by Earth's rotation can change the velocity of trapped particles by only about 1-2 kilometres per second, so rotation has been thought inconsequential for radiation-belt electrons with velocities of about 100,000 kilometres per second. Here we report that the distributions of energetic electrons across the entire spatial extent of Earth's inner radiation belt are organized in regular, highly structured and unexpected 'zebra stripes', even when the solar-wind activity is low. Modelling reveals that the patterns are produced by Earth's rotation. Radiation-belt electrons are trapped in Earth's dipole-like magnetic field, where they undergo slow longitudinal drift motion around the planet because of the gradient and curvature of the magnetic field. Earth's rotation induces global diurnal variations of magnetic and electric fields that resonantly interact with electrons whose drift period is close to 24 hours, modifying electron fluxes over a broad energy range into regular patterns composed of multiple stripes extending over the entire span of the inner radiation belt. PMID:24646996

  13. Relativistic surfatron process for Landau resonant electrons in radiation belts

    CERN Document Server

    Osmane, A

    2014-01-01

    Recent theoretical studies of the nonlinear wave-particle interactions for relativistic particles have shown that Landau resonant orbits could be efficiently accelerated along the mean background magnetic field for propagation angles $\\theta$ in close proximity to a critical propagation $\\theta_\\textrm{c}$ associated with a Hopf--Hopf bifurcation condition. In this report, we extend previous studies to reach greater modeling capacities for the study of electrons in radiation belts by including longitudinal wave effects and inhomogeneous magnetic fields. We find that even though both effects can limit the surfatron acceleration of electrons in radiation belts, gains in energy of the order of 100 keV, taking place on the order of ten milliseconds, are sufficiently strong for the mechanism to be relevant to radiation belt dynamics.

  14. Contribution of Neutron Beta Decay to Radiation Belt Pumping from High Altitude Nuclear Explosion

    Energy Technology Data Exchange (ETDEWEB)

    Marrs, R

    2002-11-13

    In 1962, several satellites were lost following high altitude nuclear tests by the United States and the Soviet Union. These satellite failures were caused by energetic electrons injected into the earth's radiation belts from the beta decay of bomb produced fission fragments and neutrons. It has been 40 years since the last high altitude nuclear test; there are now many more satellites in orbit, and it is important to understand their vulnerability to radiation belt pumping from nuclear explosions at high altitude or in space. This report presents the results of a calculation of the contribution of neutron beta decay to artificial belt pumping. For most high altitude nuclear explosions, neutrons are expected to make a smaller contribution than fission products to the total trapped electron inventory, and their contribution is usually neglected. However, the neutron contribution may dominate in cases where the fission product contribution is suppressed due to the altitude or geomagnetic latitude of the nuclear explosion, and for regions of the radiation belts with field lines far from the detonation point. In any case, an accurate model of belt pumping from high altitude nuclear explosions, and a self-consistent explanation of the 1962 data, require inclusion of the neutron contribution. One recent analysis of satellite measurements of electron flux from the 1962 tests found that a better fit to the data is obtained if the neutron contribution to the trapped electron inventory was larger than that of the fission products [l]. Belt pumping from high altitude nuclear explosions is a complicated process. Fission fragments are dispersed as part of the ionized bomb debris, which is constrained and guided by the earth's magnetic field. Those fission products that beta decay before being lost to the earth's atmosphere can contribute trapped energetic electrons to the earth's radiation belts. There has been a large effort to develop computer models for

  15. Solar Modulation of Inner Trapped Belt Radiation Dose Rate

    Science.gov (United States)

    Diaz, Abel

    2002-03-01

    The two steady sources of radiation in low Earth orbit are the inner trapped-belt and galactic cosmic radiation (GCR), which present a very significant hazard to the astronauts and flight equipment electronics. The fluxes of GCR and inner trapped-belt particles at a fixed altitude are modulated by solar activity. They decrease with increasing solar activity in general. The mechanism of these two sources of radiation are, however, very different. In this project we shall be concerned with modeling the inner trapped-belt protons. The existing trapped-belt models, namely AP-8 is based on data acquired prior to 1970 during solar cycle 20 with relatively low solar flux. These models describe the environment at solar minimum and solar maximum only. Cycles 21 and 22 were much larger, but no valid radiation model exists for such large values. Moreover, the existing models like AP-8, CRRESPRO, and GOST describe the flux to an accuracy of a factor of two to five. There is clear need to accurately predict radiation exposure of astronauts and equipment at all times between the solar minimum and solar maximum, not only on the short duration Space Shuttle flights, but also the longer term stay onboard the International Space Station. In our approach we are taking into account some important parameters, which are responsible for energy losses of protons within the belts. These energy losses are primarily to electrons and by collisions to atmospheric nuclei. Accordingly the atmospheric density dependence at a certain altitude during a specific solar activity is an important parameter that needs to be accurately incorporated into a realistic model. We are involved in developing such a model, which would enable us to predict the radiation exposure for all occasions.

  16. Radiation Belt Storm Probes (RBSP) Payload Safety Introduction Briefing

    Science.gov (United States)

    Loftin, Chuck; Lampert, Dianna; Herrburger, Eric; Smith, Clay; Hill, Stuart; VonMehlem, Judi

    2008-01-01

    Mission of the Geospace Radiation Belt Storm Probes (RBSP) is: Gain s cientific understanding (to the point of predictability) of how populations of relativistic electrons and ions in space form or change in response to changes in solar activity and the solar wind.

  17. Development of a new Global RAdiation Belt model: GRAB

    Science.gov (United States)

    Sicard-Piet, Angelica; Lazaro, Didier; Maget, Vincent; Rolland, Guy; Ecoffet, Robert; Bourdarie, Sébastien; Boscher, Daniel; Standarovski, Denis

    2016-07-01

    The well known AP8 and AE8 NASA models are commonly used in the industry to specify the radiation belt environment. Unfortunately, there are some limitations in the use of these models, first due to the covered energy range, but also because in some regions of space, there are discrepancies between the predicted average values and the measurements. Therefore, our aim is to develop a radiation belt model, covering a large region of space and energy, from LEO altitudes to GEO and above, and from plasma to relativistic particles. The aim for the first version is to correct the AP8 and AE8 models where they are deficient or not defined. At geostationary, we developed ten years ago for electrons the IGE-2006 model which was proven to be more accurate than AE8, and used commonly in the industry, covering a broad energy range, from 1keV to 5MeV. From then, a proton model for geostationary orbit was also developed for material applications, followed by the OZONE model covering a narrower energy range but the whole outer electron belt, a SLOT model to asses average electron values for 2international partnership. This model will be called the GRAB model, as Global Radiation Belt model. We will present first beta version during this conference.

  18. Modeling The Dynamics Of Outer Radiation Belt Electrons

    CERN Document Server

    Naehr, S M

    2000-01-01

    A computer model has been built to simulate the dynamic evolution of relativistic electrons in the outer radiation belt. The model calculates changes in electron flux due to three mechanisms: (1) fully-adiabatic response of electrons to variations in the magnetic field, (2) time-dependent radial diffusion, parameterized by overall magnetospheric activity, and (3) penetration of new particles into the model via a time-dependent outer boundary condition. Data from Los Alamos geosynchronous satellites, the CRRESELE statistical electron flux model, the Kp index, and the Toffoletto-Hill-Ding magnetic field model are all used to provide realistic, time-dependent inputs to the model. To evaluate the model, a simulation of the radiation belts during the November 3–12, 1993 magnetic storm was generated. Comparison of results to Global Positioning System (GPS) radiation dosimeter data indicates that the model can accurately predict storm-time flux variations for electrons with energies less than 600 keV. Mode...

  19. Large enhancement of highly energetic electrons in the outer radiation belt and its transport into the inner radiation belt inferred from MDS-1 satellite observations

    Science.gov (United States)

    Obara, T.; Matsumoto, H.

    2016-03-01

    We have examined a large increase of relativistic electrons in the outer radiation belt and its penetration into the inner radiation belt over slot region using the MDS-1 satellite observations. Result of analyses demonstrates that a large increase took place in the spring and autumn seasons, and we have newly confirmed that the penetration of outer belt electrons to the inner radiation zone took place during the big magnetic storms by examining a pitch angle distribution of the penetrating electrons.

  20. Dynamics of the earth's radiation belts and inner magnetosphere (geophysical monograph series)

    CERN Document Server

    2013-01-01

    Dynamics of the Earth's Radiation Belts and Inner Magnetosphere draws together current knowledge of the radiation belts prior to the launch of Radiation Belt Storm Probes (RPSP) and other imminent space missions, making this volume timely and unique. The volume will serve as a useful benchmark at this exciting and pivotal period in radiation belt research in advance of the new discoveries that the RPSP mission will surely bring. Highlights include the following: a review of the current state of the art of radiation belt science; a complete and up-to-date account of the wave-particle interactions that control the dynamical acceleration and loss processes of particles in the Earth's radiation belts and inner magnetosphere; a discussion emphasizing the importance of the cross-energy coupling of the particle populations of the radiation belts, ring current, and plasmasphere in controlling the dynamics of the inner magnetosphe...

  1. Dynamical behavior of whistler mode waves in the radiation belts

    Czech Academy of Sciences Publication Activity Database

    Santolík, Ondřej; Hospodarsky, G. B.; Kurth, W. S.; Averkamp, T. F.; Kletzing, C. A.

    Prague: International Union of Geodesy and Geophysics, 2015. IUGG-1762. [Earth and Environmental Sciences for Future Generations. General Assembly of International Union of Geodesy and Geophysics /26./. 22.06.2015-02.07.2015, Prague] Institutional support: RVO:68378289 Keywords : chorus and plasmaspheric hiss * Van Allen radiation belts Subject RIV: DG - Athmosphere Sciences, Meteorology http://www.iugg2015prague.com/abstractcd/data/HtmlApp/main.html#1

  2. Radiation Belt Electron Dynamics Driven by Large-Amplitude Whistlers

    Science.gov (United States)

    Khazanov, G. V.; Tel'nikhin, A. A.; Kronberg, T. K.

    2013-01-01

    Acceleration of radiation belt electrons driven by oblique large-amplitude whistler waves is studied. We show analytically and numerically that this is a stochastic process; the intensity of which depends on the wave power modified by Bessel functions. The type of this dependence is determined by the character of the nonlinear interaction due to coupling between action and phase. The results show that physically significant quantities have a relatively weak dependence on the wave power.

  3. An Experimental Concept for Probing Nonlinear Radiation Belt Physics

    Science.gov (United States)

    Amatucci, Bill; Ganguli, Guru; Crabtree, Chris; Mithaiwala, Manish; Siefring, Carl; Tejero, Erik

    2014-10-01

    The SMART sounding rocket is designed to probe the nonlinear response of a known ionospheric stimulus. High-speed neutral barium atoms generated by a shaped charge explosion perpendicular to the magnetic field in the ionosphere form a ring velocity distribution of photo-ionized Ba+ that will generate lower hybrid waves. Induced nonlinear scattering of lower hybrid waves into whistler/magnetosonic waves has been theoretically predicted, confirmed by simulations, and observed in the lab. The effects of nonlinear scattering on wave evolution and whistler escape to the radiation belts have been studied and observable signatures quantified. The fraction of the neutral atom kinetic energy converted into waves is estimated at 10-12%. SMART will carry a Ba release module and an instrumented daughter section with vector wave magnetic and electric field sensors, Langmuir probes and energetic particle detectors to determine wave spectra in the source region and detect precipitated particles. The Van Allen Probes can detect the propagation of the scattered whistlers and their effects in the radiation belts. By measuring the radiation belt whistler energy density, SMART will confirm the nonlinear scattering process and the connection to weak turbulence. Supported by the Naval Research Laboratory Base Funds.

  4. Radial diffusion of radiation belt electrons in three dimensions

    Science.gov (United States)

    Perry, Kara Lynn

    It is becoming increasingly important to understand the dynamics of radiation belt energetic particles given their potentially hazardous effects on satellites and our ever-increasing dependence on those satellites. There is a need to determine whether existing two-dimensional models are adequate in estimating the dynamics of the radiation belts or if a three-dimensional model is required. Discussion of general space physics and radiation belt topology is followed by an account of existing models and how these models can be improved by extending dynamic calculations from two dimensions to three. A model is then developed describing magnetic and electric fields associated with poloidal mode Pc5 ULF waves. The frequency and L dependence of the ULF wave power is included in this model by incorporating published ground-based magnetometer data. The influence of ultra low frequency (ULF) waves in the Pc5 frequency range on radiation belt electrons in a dipole magnetic field is examined. This is the first analysis in three dimensions utilizing model ULF wave electric and magnetic fields in the guiding center trajectories of relativistic electrons. It is demonstrated here that realistic spectral characteristics play a significant role in the rate of diffusion of relativistic electrons via drift resonance with poloidal mode ULF waves. Radial diffusion rates including bounce motion are calculated for alphaeq ≥ 50° (lambda ≤ 20°). Energy, L and pitch angle dependence of diffusion rates are calculated for L-independent, L-dependent, frequency independent and frequency dependent field power. During geomagnetic storms when ULF wave power is increased, ULF waves are a significant driver of increased fluxes of relativistic electrons inside geosynchronous orbit. Diffusion time scales obtained here, when frequency and L dependence compared to observations of ULF wave power is included, support this conclusion. A compression is then added to the dipole field model and diffusion

  5. Rapid energization of radiation belt electrons by nonlinear wave trapping

    Directory of Open Access Journals (Sweden)

    Y. Katoh

    2008-11-01

    Full Text Available We show that nonlinear wave trapping plays a significant role in both the generation of whistler-mode chorus emissions and the acceleration of radiation belt electrons to relativistic energies. We have performed particle simulations that successfully reproduce the generation of chorus emissions with rising tones. During this generation process we find that a fraction of resonant electrons are energized very efficiently by special forms of nonlinear wave trapping called relativistic turning acceleration (RTA and ultra-relativistic acceleration (URA. Particle energization by nonlinear wave trapping is a universal acceleration mechanism that can be effective in space and cosmic plasmas that contain a magnetic mirror geometry.

  6. Ultra low frequency waves impact on radiation belt energetic particles

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    One of the most fundamental important issues in the space physics is to understand how solar wind energy transports into the inner magnetosphere.Ultra low frequency(ULF)wave in the magnetosphere and its impact on energetic particles,such as the wave-particle resonance,modulation,and particle acceleration,are extremely important topics in the Earth’s radiation belt dynamics and solar wind― magnetospheric coupling.In this review,we briefly introduce the recent advances on ULF waves study. Further,we will explore the density structures and ion compositions around the plasmaspheric boundary layer(PBL)and discuss its possible relation to the ULF waves.

  7. Atmospheric scattering and decay of inner radiation belt electrons

    Science.gov (United States)

    Selesnick, R. S.

    2012-08-01

    The dynamics of inner radiation belt electrons are governed by competing source, loss, and transport processes. However, during the recent extended solar minimum period the source was inactive and electron intensity was characterized by steady decay. This provided an opportunity to determine contributions to the decay rate of losses by precipitation into the atmosphere and of diffusive radial transport. To this end, a stochastic simulation of inner radiation belt electron transport is compared to data taken by the IDP instrument on the DEMETER satellite during 2009. For quasi-trapped, 200 keV electrons atL= 1.3, observed in the drift loss cone (DLC), results are consistent with electron precipitation losses by atmospheric scattering alone, provided account is taken of non-diffusive wide-angle scattering. Such scattering is included in the stochastic simulation using a Markov jump process. Diffusive small-angle atmospheric scattering, while causing most of the precipitation losses, is too slow relative to azimuthal drift to contribute significantly to DLC intensity. Similarly there is no contribution from scattering by VLF plasma waves. Energy loss, energy diffusion, and azimuthal drift are also included in the model. Even so, observed decay rates of stably-trapped electrons withL diffusion with coefficient DLL ˜ 3 × 10-10 s-1 to replenish electrons lost to the atmosphere at low L values.

  8. Wave Energy Budget in the Earth Radiation Belts

    Science.gov (United States)

    Artemyev, Anton; Agapitov, Oleksiy; Mourenas, Didier; Krasnoselskikh, Vladimir; Mozer, Forest

    2015-04-01

    Whistlers are important electromagnetic waves pervasive in Earth's magnetosphere, where they continuously remove or energize electrons trapped by the geomagnetic field, controlling radiation hazards to satellites and astronauts and ionization or chemical composition in the upper-atmosphere. Here, we report an analysis of ten-year Cluster data, evaluating for the first time the wave energy budget in Earth's magnetosphere and revealing that a significant fraction of the energy corresponds to hitherto generally neglected very oblique waves. Such waves, with ten times smaller magnetic power than parallel waves, typically have similar total energy. Very oblique waves may turn out to be a crucial agent of energy redistribution in Earth's radiation belts, controlled by solar activity.

  9. Exploring the Jupiter's and Saturn's radiation belts with LOFAR

    Science.gov (United States)

    Girard, Julien N.; Zarka, Philippe; Pater Imke, de; Hess, Sebastien; Tasse, Cyril; Courtin, Regis; Hofstadter, Mark; Santos-Costa, Daniel; Nettelmann, Nadine; lorenzato, Lise

    2014-05-01

    Since its detection in the mid-fifties, the decimeter synchrotron radiation (DIM), originating from the radiation belts of Jupiter, has been extensively observed over a wide spectrum (from >300 MHz to 22 GHz) by various radio instruments (VLA, ATCA, WSRT, Cassini...). They provided accurate flux measurements as well as resolved maps of the emission that revealed spatial, temporal and spectral variabilities. The strong magnetic field (~4.2 G at the equator) is responsible for the radio emission generated by relativistic electrons. The emission varies at different time scales (short-time variations of hours to long-term variation over decades) due to the combination of visibility configuration (fast rotating 'dipole' magnetic field, beamed radio emission) and intrinsic local variations (interaction between relativistic electrons and satellites/dust, delayed effect of the solar wind ram pressure, impacts events) (e.g. de Pater & Klein, 1989; de Pater & Dunn, 2003; Bagenal (ed.) et al., 2004; Santos-Costa, 2009, 2011). A complete framework is necessary to fully understand the source, loss and transport processes of the electrons populating the inner magnetosphere over a wide frequency range. The low frequencies are associated with electron of lower energies situated in weaker magnetic field regions. LOFAR, the LOw Frequency ARray (LOFAR) (van Haarlem et al., 2012), the last generation of versatile and digital ground-based radio interferometer operates in the [30-250] MHz bandwidth. It brings very high time (~μsec), frequency (~kHz) and angular (~asec) resolutions and huge sensitivities (~mJy). In November 2011, a single 10-hour track enabled to cover an entire planetary rotation and led to image, for the first time, the radiation belts between 127-172 MHz (Girard et al. 2012, 2013). In Feb 2013, an 11-hour joint LOFAR/WSRT observing campaign seized the dyname state of the radiation belts from 45 MHz up to 5 GHz. We will present the current study of the radiation belts

  10. Insights on radiation belt physics from the dynamics radiation environment assimilation model, DREAM

    International Nuclear Information System (INIS)

    Complete text of publication follows. The Dynamic Radiation Environment Assimilation Model (DREAM) is a coupled, inner magnetosphere model with modules that include the ring current, the radiation belts, self-consistent global magnetic fields, Kalman filter data assimilation, and customized user applications. DREAM was developed at Los Alamos National Laboratory with the goals of specifying, predicting and understanding the near-Earth space environment. Here we will focus on new understanding of physics of the inner magnetosphere that DREAM has provided and, even more specifically, on the physics of radiation belt acceleration, transport, and loss. One early and important contribution was providing definitive evidence that local acceleration processes acting inside or near geosynchronous orbit are required in order to explain radiation belt dynamics. Another critical process we investigated was loss of radiation belt electrons by radial diffusion or transport to the magnetopause. A critical calculation here is accurate determination of the adiabatic redistribution of particles due to the storm-time ring current (the 'Dst' effect) which can cause both apparent 'loss' of particles at a given satellite. At different times and at different energies, DREAM can determine whether the region outside the trapping boundary acts as a source (the plasma sheet) a sink (the magnetopause) or a combination of both. Another fundamental sink of radiation belt electrons is the atmospheric loss cone where pitch angle scattering can remove electrons trough precipitation. In the final topic for this talk we will describe how we use DREAM to determine the relationship between trapped and precipitating populations and how we relate LEO measurements to high-altitude measurements using observed and modeled characteristics of magnetospheric wave populations.

  11. Inward diffusion and loss of radiation belt protons

    Science.gov (United States)

    Selesnick, R. S.; Baker, D. N.; Jaynes, A. N.; Li, X.; Kanekal, S. G.; Hudson, M. K.; Kress, B. T.

    2016-03-01

    Radiation belt protons in the kinetic energy range 24 to 76 MeV are being measured by the Relativistic Electron Proton Telescope on each of the two Van Allen Probes. Data have been processed for the purpose of studying variability in the trapped proton intensity during October 2013 to August 2015. For the lower energies (≲32 MeV), equatorial proton intensity near L = 2 showed a steady increase that is consistent with inward diffusion of trapped solar protons, as shown by positive radial gradients in phase space density at fixed values of the first two adiabatic invariants. It is postulated that these protons were trapped with enhanced efficiency during the 7 March 2012 solar proton event. A model that includes radial diffusion, along with known trapped proton source and loss processes, shows that the observed average rate of increase near L = 2 is predicted by the same model diffusion coefficient that is required to form the entire proton radiation belt, down to low L, over an extended (˜103 year) interval. A slower intensity decrease for lower energies near L = 1.5 may also be caused by inward diffusion, though it is faster than predicted by the model. Higher-energy (≳40 MeV) protons near the L = 1.5 intensity maximum are from cosmic ray albedo neutron decay. Their observed intensity is lower than expected by a factor ˜2, but the discrepancy is resolved by adding an unspecified loss process to the model with a mean lifetime ˜120 years.

  12. Imaging Jupiter's radiation belts down to 127 MHz with LOFAR

    CERN Document Server

    Girard, J N; Tasse, C; Hess, S; de Pater, I; Santos-Costa, D; Nenon, Q; Sicard, A; Bourdarie, S; Anderson, J; Asgekar, A; Bell, M E; van Bemmel, I; Bentum, M J; Bernardi, G; Best, P; Bonafede, A; Breitling, F; Breton, R P; Broderick, J W; Brouw, W N; Brüggen, M; Ciardi, B; Corbel, S; Corstanje, A; de Gasperin, F; de Geus, E; Deller, A; Duscha, S; Eislöffel, J; Falcke, H; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Hessels, J W T; Hoeft, M; Hörandel, J; Iacobelli, M; Juette, E; Kondratiev, V I; Kuniyoshi, M; Kuper, G; van Leeuwen, J; Loose, M; Maat, P; Mann, G; Markov, S; McFadden, R; McKay-Bukowski, D; Moldon, J; Munk, H; Nelles, A; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Röttgering, H; Rowlinson, A; Schwarz, D; Smirnov, O; Steinmetz, M; Swinbank, J; Tagger, M; Thoudam, S; Toribio, M C; Vermeulen, R; Vocks, C; van Weeren, R J; Wijers, R A M J; Wucknitz, O

    2015-01-01

    Context. Observing Jupiter's synchrotron emission from the Earth remains today the sole method to scrutinize the distribution and dynamical behavior of the ultra energetic electrons magnetically trapped around the planet (because in-situ particle data are limited in the inner magnetosphere). Aims. We perform the first resolved and low-frequency imaging of the synchrotron emission with LOFAR at 127 MHz. The radiation comes from low energy electrons (~1-30 MeV) which map a broad region of Jupiter's inner magnetosphere. Methods (see article for complete abstract) Results. The first resolved images of Jupiter's radiation belts at 127-172 MHz are obtained along with total integrated flux densities. They are compared with previous observations at higher frequencies and show a larger extent of the synchrotron emission source (>=4 $R_J$). The asymmetry and the dynamic of east-west emission peaks are measured and the presence of a hot spot at lambda_III=230 {\\deg} $\\pm$ 25 {\\deg}. Spectral flux density measurements ar...

  13. Nonlinear VLF Wave Physics in the Radiation Belts

    Science.gov (United States)

    Crabtree, C. E.; Tejero, E. M.; Ganguli, G.; Mithaiwala, M.; Rudakov, L.; Hospodarsky, G. B.; Kletzing, C.

    2014-12-01

    Electromagnetic VLF waves, such as whistler mode waves, both control the lifetime of trapped electrons in the radiation belts by pitch-angle scattering and are responsible for the energization of electrons during storms. Traditional approaches to understanding the influence of waves on trapped electrons have assumed that the wave characteristics (frequency spectrum, wave-normal angle distribution, etc.) were both stationary in time and amplitude independent from event to event. In situ data from modern satellite missions, such as the Van Allen probes, are showing that this assumption may not be justified. In addition, recent theoretical results [Crabtree et al. 2012] show that the threshold for nonlinear wave scattering can often be met by naturally occurring VLF waves in the magnetosphere, with wave magnetic fields of the order of 50-100 pT inside the plasmapause. Nonlinear wave scattering (Nonlinear Landau Damping) is an amplitude dependent mechanism that can strongly alter VLF wave propagation [Ganguli et al. 2010], primarily by altering the direction of propagation. Laboratory results have confirmed the dramatic change in propagation direction when the pump wave has sufficient amplitude to exceed the nonlinear threshold [Tejero et al. 2014]. Nonlinear scattering can alter the macroscopic dynamics of waves in the radiation belts leading to the formation of a long-lasting wave-cavity [Crabtree et al. 2012] and, when amplification is present, a multi-pass amplifier [Ganguli et al., 2012]. Such nonlinear wave effects can dramatically reduce electron lifetimes. Nonlinear wave dynamics such as these occur when there are more than one wave present, such a condition necessarily violates the assumption of traditional wave-normal analysis [Santolik et al., 2003] which rely on the plane wave assumption. To investigate nonlinear wave dynamics using modern in situ data we apply the maximum entropy method [Skilling and Bryan, 1984] to solve for the wave distribution function

  14. Proton flux under radiation belts: near-equatorial zone

    International Nuclear Information System (INIS)

    In this work the features of low-energy proton flux increases in near-equatorial region (McIlvein parameter Lth the proton flux (with energy from tens keV up to several MeV) increases are registering regularly. However modern proton flux models (for example AP8 model) works at L>1.15 only and does not take into account near-equatorial protons. These fluxes are not too big, but the investigation of this phenomenon is important in scope of atmosphere-ionosphere connections and mechanisms of particles transport in magnetosphere. In according to double charge-exchange model the proton flux in near-equatorial region does not depend on geomagnetic local time (MLT) and longitude. However the Azur satellite data and Kosmos-484, MIR station and Active satellite data revealed the proton flux dependence on longitude. The other feature of near-equatorial proton flux is the dependence on geomagnetic local time revealed in the Sampex satellite experiment and other experiments listed above. In this work the dependences on MLT and longitude are investigated using the Active satellite (30-500 keV) and Sampex satellite (>800 keV). This data confirms that main sources of near-equatorial protons are radiation belts and ring current. The other result is that near-equatorial protons are quasi-trapped. The empirical proton flux dependences on L, B at near-equatorial longitudes are presented. (author)

  15. Saturn's radiation belts in the view of Cassini's MIMI/LEMMS observations

    Science.gov (United States)

    Roussos, Elias; Krupp, Norbert; Kollmann, Peter; Paranicas, Chris; Armstrong, Tom P.; Mitchell, Donald G.; Krimigis, Stamatios M.; Kotova, Anna

    2013-04-01

    Energetic charged particle measurements by Cassini's MIMI/LEMMS detector between 2004 and 2013 have revealed that the processes which form and sustain Saturn's radiation belts differ significantly for their electron and ion components. The permanent MeV ion belts are relatively stable in intensity over both short and long time scales, they have a outer boundary that continuously coincides with the L-shell of Saturn's moon Tethys (L=4.89) and comprise different sectors, each separated from the other by an ion depleted region that is centered on an L-shell of one of the planet's inner icy moons. Fluxes within these belts are dominated by secondaries that result from nuclear collisions between Galactic Cosmic Rays and the planet's main rings and atmosphere. Extensions of the ion belts beyond the orbit of Tethys, that may last several months, may occur after the interaction of Saturn's magnetosphere with a Solar Proton Event. Still, these transient extensions have no impact on the structure of the inner belts, making these inner belts ideal for detailed and a precise studies of nuclear source processes, such as CRAND. Contrary to the ion belts, the electron radiation belt is a continuous structure that extends between the outer edge of the main rings and has its outer boundary at an average distance of about 8 Saturn radii from the planet. The latter distance scatters considerably from orbit to orbit, while flux levels within the belt may vary by several orders of magnitude. MIMI/LEMMS observations show a series of interesting features, such as recurrent sudden belt expansions with periods in the order of one to several weeks and considerably variable responses following periods of ICME interactions with Saturn's magnetosphere. As the elecron belts extend until the very dynamic middle magnetosphere and the dominant electron source and loss processes change as a function of L-shell, energy and pitch angle, modelling of these belts is very challenging.

  16. The Roles of Transport and Wave-Particle Interactions on Radiation Belt Dynamics

    Science.gov (United States)

    Fok, Mei-Ching; Glocer, Alex; Zheng, Qiuhua

    2011-01-01

    Particle fluxes in the radiation belts can vary dramatically during geomagnetic active periods. Transport and wave-particle interactions are believed to be the two main types of mechanisms that control the radiation belt dynamics. Major transport processes include substorm dipolarization and injection, radial diffusion, convection, adiabatic acceleration and deceleration, and magnetopause shadowing. Energetic electrons and ions are also subjected to pitch-angle and energy diffusion when interact with plasma waves in the radiation belts. Important wave modes include whistler mode chorus waves, plasmaspheric hiss, electromagnetic ion cyclotron waves, and magnetosonic waves. We investigate the relative roles of transport and wave associated processes in radiation belt variations. Energetic electron fluxes during several storms are simulated using our Radiation Belt Environment (RBE) model. The model includes important transport and wave processes such as substorm dipolarization in global MHD fields, chorus waves, and plasmaspheric hiss. We discuss the effects of these competing processes at different phases of the storms and validate the results by comparison with satellite and ground-based observations. Keywords: Radiation Belts, Space Weather, Wave-Particle Interaction, Storm and Substorm

  17. Global-scale coherence modulation of radiation-belt electron loss from plasmaspheric hiss

    Science.gov (United States)

    Breneman, A. W.; Halford, A.; Millan, R.; McCarthy, M.; Fennell, J.; Sample, J.; Woodger, L.; Hospodarsky, G.; Wygant, J. R.; Cattell, C. A.; Goldstein, J.; Malaspina, D.; Kletzing, C. A.

    2015-07-01

    Over 40 years ago it was suggested that electron loss in the region of the radiation belts that overlaps with the region of high plasma density called the plasmasphere, within four to five Earth radii, arises largely from interaction with an electromagnetic plasma wave called plasmaspheric hiss. This interaction strongly influences the evolution of the radiation belts during a geomagnetic storm, and over the course of many hours to days helps to return the radiation-belt structure to its `quiet' pre-storm configuration. Observations have shown that the long-term electron-loss rate is consistent with this theory but the temporal and spatial dynamics of the loss process remain to be directly verified. Here we report simultaneous measurements of structured radiation-belt electron losses and the hiss phenomenon that causes the losses. Losses were observed in the form of bremsstrahlung X-rays generated by hiss-scattered electrons colliding with the Earth's atmosphere after removal from the radiation belts. Our results show that changes of up to an order of magnitude in the dynamics of electron loss arising from hiss occur on timescales as short as one to twenty minutes, in association with modulations in plasma density and magnetic field. Furthermore, these loss dynamics are coherent with hiss dynamics on spatial scales comparable to the size of the plasmasphere. This nearly global-scale coherence was not predicted and may affect the short-term evolution of the radiation belts during active times.

  18. The impact of radiation belts region on top side ionosphere condition during last solar minimum.

    Science.gov (United States)

    Rothkaehl, Hanna; Przepiórka, Dororta; Matyjasiak, Barbara

    2014-05-01

    The wave particle interactions in radiation belts region are one of the key parameters in understanding the global physical processes which govern the near Earth environment. The populations of outer radiation belts electrons increasing in response to changes in the solar wind and the interplanetary magnetic field, and decreasing as a result of scattering into the loss cone and subsequent absorption by the atmosphere. The most important question in relation to understanding the physical processes in radiation belts region relates to estimate the ratio between acceleration and loss processes. This can be also very useful for construct adequate models adopted in Space Weather program. Moreover the wave particle interaction in inner radiation zone and in outer radiation zone have significant influence on the space plasma property at ionospheric altitude. The aim of this presentation is to show the manifestation of radiation belts region at the top side ionosphere during the last long solar minimum. The presentation of longitude and seasonal changes of plasma parameters affected by process occurred in radiation belts region has been performed on the base of the DEMETER and COSMIC 3 satellite registration. This research is partly supported by grant O N517 418440

  19. Modelling the outer radiation belt as a complex system in a self-organised critical state

    Directory of Open Access Journals (Sweden)

    N. B. Crosby

    2005-01-01

    Full Text Available The dynamic behaviour of the outer electron radiation belt makes this area of geo-space a candidate for the concept of self-organized criticality. It is shown here that frequency distributions of measured outer electron radiation belt data are well-represented by power-laws over two decades. Applying the concept of self-organized criticality to interpret the shape of the distributions suggests another approach to complement existing methods in the interpretation of how this complicated environment works. Furthermore sub-grouping the radiation belt count rate data as a function of spatial location or temporal interval (e.g. L-shell, magnetic local time, solar cycle, ... shows systematic trends in the value of the slope of the power-laws. It is shown that the inner part of the outer radiation belt is influenced in a similar manner to the outer part, but in a less profound way. Our results suggest that the entire outer radiation belt appears to be affected as the sum of its individual parts. This type of study also gives the probability of exceeding a given threshold value over a given time; limiting the size of 'an event'. The average values could then be compared with models used in spacecraft design.

  20. Simulation of ULF wave-modulated radiation belt electron precipitation during the 17 March 2013 storm

    Science.gov (United States)

    Brito, T.; Hudson, M. K.; Kress, B.; Paral, J.; Halford, A.; Millan, R.; Usanova, M.

    2015-05-01

    Balloon-borne instruments detecting radiation belt precipitation frequently observe oscillations in the millihertz frequency range. Balloons measuring electron precipitation near the poles in the 100 keV to 2.5 MeV energy range, including the MAXIS, MINIS, and most recently the Balloon Array for Relativistic Radiation belt Electron Losses balloon experiments, have observed this modulation at ULF wave frequencies. Although ULF waves in the magnetosphere are seldom directly linked to increases in electron precipitation since their oscillation periods are much larger than the gyroperiod and the bounce period of radiation belt electrons, test particle simulations show that this interaction is possible. Three-dimensional simulations of radiation belt electrons were performed to investigate the effect of ULF waves on precipitation. The simulations track the behavior of energetic electrons near the loss cone, using guiding center techniques, coupled with an MHD simulation of the magnetosphere, using the Lyon-Fedder-Mobarry code, during a coronal mass ejection (CME)-shock event on 17 March 2013. Results indicate that ULF modulation of precipitation occurs even without the presence of electromagnetic ion cyclotron waves, which are not resolved in the MHD simulation. The arrival of a strong CME-shock, such as the one simulated, disrupts the electric and magnetic fields in the magnetosphere and causes significant changes in both components of momentum, pitch angle, and L shell of radiation belt electrons, which may cause them to precipitate into the loss cone.

  1. RCM-VERB coupled simulations of the dynamics of the radiation belts during storms

    International Nuclear Information System (INIS)

    Complete text of publication follows. The evolution of the relativistic electron fluxes in the radiation belts can be described by the 3D modified Fokker-Planck equation in terms of radial distance, pitch-angle, and energy. Recently developed at UCLA VERB code models the dynamics of relativistic electrons subjected to ULF, ELF, and VLF waves including radial diffusion driven by PC4-5 waves; pitch-angle scattering by hiss, chorus, anthropogenic whistlers, lightning generated whistlers, and EMIC waves; and local acceleration driven by chorus waves. Numerical simulations of a geomagnetic storm using VERB code, coupled with RCM are presented. Dynamics of the 10-100 keV electrons is inferred from RCM simulations and is used as an electrons seed population for the radiation belts modeling using VERB code. Presented sensitivity numerical simulations show the influence of the time-dependent convective sources on the radiation belt dynamics.

  2. Trapping in stochastic mechanics and applications to covers of clouds and radiation belts

    International Nuclear Information System (INIS)

    It is possible to assign a stochastic acceleration to conservative stochastic diffusion processes. As a basic assumption, this stochastic acceleration is set equal to the deterministic smooth component of the external force acting on the particle, whereas the influences of the remainder is modelled by a diffusion coefficient. In this paper, we shall try to see whether it can account for the observation in two cases: the cover of clouds of planets and the radiation belts in the planetary magnetic field. We describe the basic properties of Newtonian Diffusion Stochastic Processes and indicate their connection with Schroedinger-like equations. Furthermore we give a heuristic interpretation of the nodal surfaces as impenetrable barriers for Newtonian Stochastic Diffusion Processes. The possible applications to the observed average cloud covering in the planetary atmosphere are presented we discuss the radiation belts (Van Allen Belts) along the previous ideas

  3. III. Artificial sources of ionizing radiation

    International Nuclear Information System (INIS)

    A theoretical explanation is given of obtaining electrons by thermal emission. The Coolidge X-ray tube is described. The spectral composition is presented of X radiation, changes in the spectrum of X radiation bremsstrahlung in dependence on anode potential and on different shapes of the rectifier of the high voltage curve. X-ray spectrography of crystals is presented as an example of the use of X radiation. Linear accelerators (simple and multiple), microtrons, cyclotrons and betatrons are used for obtaining higher energy radiation. The principle is given for each accelerator and examples of acclerators are given such as are used in clinical practice and in radiotherapy. (E.S.)

  4. Innermost Van Allen Radiation Belt for High Energy Protons at Saturn

    Science.gov (United States)

    Cooper, John F.

    2008-01-01

    The high energy proton radiation belts of Saturn are energetically dominated by the source from cosmic ray albedo neutron decay (CRAND), trapping of protons from beta decay of neutrons emitted from galactic cosmic ray nuclear interactions with the main rings. These belts were originally discovered in wide gaps between the A-ring, Janus/Epimetheus, Mimas, and Enceladus. The narrow F and G rings significant affected the CRAND protons but did not produce total depletion. Voyager 2 measurements subsequently revealed an outermost CRAND proton belt beyond Enceladus. Although the source rate is small, the trapping times limited by radial magnetospheric diffusion are very long, about ten years at peak measured flux inwards of the G ring, so large fluxes can accumulate unless otherwise limited in the trapping region by neutral gas, dust, and ring body interactions. One proposed final extension of the Cassini Orbiter mission would place perikrone in a 3000-km gap between the inner D ring and the upper atmosphere of Saturn. Experience with CRAND in the Earth's inner Van Allen proton belt suggests that a similar innermost belt might be found in this comparably wide region at Saturn. Radial dependence of magnetospheric diffusion, proximity to the ring neutron source, and northward magnetic offset of Saturn's magnetic equator from the ring plane could potentially produce peak fluxes several orders of magnitude higher than previously measured outside the main rings. Even brief passes through such an intense environment of highly penetrating protons would be a significant concern for spacecraft operations and science observations. Actual fluxes are limited by losses in Saturn's exospheric gas and in a dust environment likely comparable to that of the known CRAND proton belts. The first numerical model of this unexplored radiation belt is presented to determine limits on peak magnitude and radial profile of the proton flux distribution.

  5. Reanalysis and forecasting killer electrons in Earth's radiation belts using the VERB code

    Science.gov (United States)

    Kellerman, Adam; Kondrashov, Dmitri; Shprits, Yuri; Podladchikova, Tatiana; Drozdov, Alexander

    2016-07-01

    The Van Allen radiation belts are torii-shaped regions of trapped energetic particles, that in recent years, have become a principle focus for satellite operators and engineers. During geomagnetic storms, electrons can be accelerated up to relativistic energies, where they may penetrate spacecraft shielding and damage electrical systems, causing permanent damage or loss of spacecraft. Data-assimilation provides an optimal way to combine observations of the radiation belts with a physics-based model in order to more accurately specify the global state of the Earth's radiation belts. We present recent advances to the data-assimilative version of the Versatile Electron Radiation Belt (VERB) code, including more sophisticated error analysis, and incorporation of realistic field-models to more accurately specify fluxes at a given MLT or along a spacecraft trajectory. The effect of recent stream-interaction-region (SIR) driven enhancements are investigated using the improved model. We also present a real-time forecast model based on the data-assimilative VERB code, and discuss the forecast performance over the past 12 months.

  6. Studies on the evaluation of thermal belts and radiation fog over mountainous regions by LANDSAT data

    International Nuclear Information System (INIS)

    Local meteorological phenomena and characteristics under conditions of nocturnal radiative cooling in winter were investigated using Landsat data and physiographic parameters over the hilly and mountainous regions of the western part of shikoku. (1) Relative elevation between thermal belts and underlying ground such as bottom of basin or valley was 400m on an average. (2) Thermal belts appeared in the zone between 400m and 1000m above the sea level in the western part of Shikoku. (3) Temperature of the thermal belts varied with the elevation in a ratio of about 1 degrees C/100m. This observation indicated that the thermal belt temperature was closely related to the altitude of the zone where the thermal belts originated. (4) Radiation fog was frequently recorded over some part along the Hiji river and over the area along Ootoyo to Motoyama; fog was present even at 10 a.m. (3 hours after sunrise). (5) Upper surface of the fog layer was located at 200m and 600m above the sea level in the Oozu basin and in the area along Ootoyo to Motoyama respectively. (6) In the Oozu basin, the distribution of hamlets on the mountainside was often recognized in the localities within the upper limit of foggy areas

  7. Nonstorm loss of relativistic electrons in the outer radiation belt

    Science.gov (United States)

    Katsavrias, Ch.; Daglis, I. A.; Turner, D. L.; Sandberg, I.; Papadimitriou, C.; Georgiou, M.; Balasis, G.

    2015-12-01

    We report observations of electron Phase Space Density (PSD) dropout and evidence that supports the loss mechanism of magnetopause shadowing and outward radial diffusion during a nonstorm period characterized by persistently positive values of the SYM->H index. On 14 April 2013 an electron PSD dropout of 2 orders of magnitude was observed at the nightside magnetosphere by the Van Allen Probes. The magnetopause shadowing was associated with a strong pulse attributed to the arrival of an interplanetary coronal mass ejection. It is shown, for the first time in detail, that significant losses to the magnetosheath may occur even in the absence of significant reconnection and magnetic storm activity. Signatures of substorm injections that penetrate the outer belt and enhance the low-energy electrons were also observed right after the interplanetary pressure pulse. Moreover, particle measurements from THEMIS constellation also show a PSD depletion in the dayside magnetosphere.

  8. Wave Distribution Functions of Plasmaspheric Hiss and their Effects on Radiation Belt Dynamics

    Science.gov (United States)

    Santolik, O.; Ripoll, J. F.; Kurth, W. S.; Hospodarsky, G. B.; Kletzing, C.

    2015-12-01

    Plasmaspheric hiss is formed by whistler-mode waves which play an important role in the dynamics the Earth's radiation belts, specifically in connection with the slot region between the inner and outer Van Allen belts. The origin of plasmaspheric hiss is still a subject of discussions and these waves are known for their complex propagation properties. They are often far from a single plane wave approximation, forming a continuous distribution of the wave energy density with respect to the wave vector direction (wave distribution function). Analysis of polarization and propagation parameters of these waves provides us with inputs for modeling of radiation belt dynamics. We use the data of the Waves instrument of Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) onboard the Van Allen Probes spacecraft, to analyze simultaneous measurements of all electric and magnetic field components, together with measurements of the plasma density based on the determination of the upper hybrid resonance frequency. Using this unique data set we estimate the wave distribution functions of plasmaspheric hiss and we model the effects of these waves on the decay rates of radiation belt electrons through quasilinear pitch angle diffusion.

  9. Perception of natural, medical, and 'artificial' radiation exposures

    International Nuclear Information System (INIS)

    The paper discusses the imbalances in public perception and weighting factors attached by the media and consequently by politicians and by the general public, to the risks associated with the three main sources of population exposure, namely: natural radiation, diagnostic or therapeutic medical exposure and other artificial components including nuclear weapons tests, nuclear fuel cycles and reactor accidents. 15 refs

  10. Modeling Earth's Outer Radiation Belt Electron Dynamics---Radial Diffusion, Heating, and Loss

    Science.gov (United States)

    Tu, Weichao

    Earth's outer radiation belt is a relativistic electron environment that is hazardous to space systems. It is characterized by large variations in the electron flux, which are controlled by the competition between source, transport, and loss processes. One of the central questions in outer radiation belt research is to resolve the relative contribution of radial diffusion, wave heating, and loss to the enhancement and decay of the radiation belt electrons. This thesis studies them together and separately. Firstly, we develop an empirical Fokker-Planck model that includes radial diffusion, an internal source, and finite electron lifetimes parameterized as functions of geomagnetic indices. By simulating the observed electron variations, the model suggests that the required magnitudes of radial diffusion and internal heating for the enhancement of energetic electrons in the outer radiation belt vary from storm to storm, and generally internal heating contributes more to the enhancements of MeV energy electrons at L=4 (L is approximately the radial distance in Earth radii at the equator). However, since the source, transport, and loss terms in the model are empirical, the model results have uncertainties. To eliminate the uncertainty in the loss rate, both the precipitation and the adiabatic loss of radiation belt electrons are quantitatively studied. Based on the observations from Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX), a Drift-Diffusion model is applied to quantify electron precipitation loss, which is the dominant non-adiabatic loss mechanism for electrons in the heart of the outer radiation belt. Model results for a small storm, a moderate storm, and an intense storm indicate that fast precipitation losses of relativistic electrons, on the time scale of hours, persistently occur in the storm main phases and with more efficient losses at higher energies over wide range of L regions. Additionally, calculations of adiabatic effects on radiation

  11. Earth's Radiation Belts: The View from Juno's Cameras

    Science.gov (United States)

    Becker, H. N.; Joergensen, J. L.; Hansen, C. J.; Caplinger, M. A.; Ravine, M. A.; Gladstone, R.; Versteeg, M. H.; Mauk, B.; Paranicas, C.; Haggerty, D. K.; Thorne, R. M.; Connerney, J. E.; Kang, S. S.

    2013-12-01

    Juno's cameras, particle instruments, and ultraviolet imaging spectrograph have been heavily shielded for operation within Jupiter's high radiation environment. However, varying quantities of >1-MeV electrons and >10-MeV protons will be energetic enough to penetrate instrument shielding and be detected as transient background signatures by the instruments. The differing shielding profiles of Juno's instruments lead to differing spectral sensitivities to penetrating electrons and protons within these regimes. This presentation will discuss radiation data collected by Juno in the Earth's magnetosphere during Juno's October 9, 2013 Earth flyby (559 km altitude at closest approach). The focus will be data from Juno's Stellar Reference Unit, Advanced Stellar Compass star cameras, and JunoCam imager acquired during coordinated proton measurements within the inner zone and during the spacecraft's inbound and outbound passages through the outer zone (L ~3-5). The background radiation signatures from these cameras will be correlated with dark count background data collected at these geometries by Juno's Ultraviolet Spectrograph (UVS) and Jupiter Energetic Particle Detector Instrument (JEDI). Further comparison will be made to Van Allen Probe data to calibrate Juno's camera results and contribute an additional view of the Earth's radiation environment during this unique event.

  12. Measurement of Radiation Belt Partcles by MDS-1 Onboard SEDA

    Science.gov (United States)

    Matsumoto, H.; Koshiishi, H.; Goka, T.

    The Space Environment Data Acquisition Equipment (SEDA) is on board the Mission Demonstration Test Satellite-1 (MDS-1) to measure the radiation environment, which was launched into geo-stationary transfer orbit (GTO) on February 4, 2002 with an apogee of about 35,700km, a perigee of about 500 km and an inclination of about 28.5 degrees. SEDA consists of the four instruments. Standard Dose Monitor monitors the electron and proton flux. Dosimeter measures the integrated radiation dose at fifty-six points of the satellite. Heavy Ion Telescope monitors the flux of heavy ions from He to Fe. Magnetometer measures the magnetic field in the magnetosphere. In this paper are described first results and comparison with the ISO standard model for the space environment

  13. Imaging Jupiter's radiation belts down to 127 MHz with LOFAR

    OpenAIRE

    Girard, J. N.; Zarka, P.; Tasse, C.; Hess, S.; de Pater, I.; Santos-Costa, D.; Nenon, Q.; Sicard, A.; Bourdarie, S.; J. Anderson; Asgekar, A.; Bell, M. E.; van Bemmel, I.; Bentum, M. J.; Bernardi, G.

    2015-01-01

    Context. Observing Jupiter's synchrotron emission from the Earth remains today the sole method to scrutinize the distribution and dynamical behavior of the ultra energetic electrons magnetically trapped around the planet (because in-situ particle data are limited in the inner magnetosphere). Aims. We perform the first resolved and low-frequency imaging of the synchrotron emission with LOFAR at 127 MHz. The radiation comes from low energy electrons (~1-30 MeV) which map a broad region of Jupit...

  14. Volterra network modeling of the nonlinear finite-impulse reponse of the radiation belt flux

    Science.gov (United States)

    Taylor, M.; Daglis, I. A.; Anastasiadis, A.; Vassiliadis, D.

    2011-01-01

    We show how a general class of spatio-temporal nonlinear impulse-response forecast networks (Volterra networks) can be constructed from a taxonomy of nonlinear autoregressive integrated moving average with exogenous inputs (NAR-MAX) input-output equations, and used to model the evolution of energetic particle f uxes in the Van Allen radiation belts. We present initial results for the nonlinear response of the radiation belts to conditions a month earlier. The essential features of spatio-temporal observations are recovered with the model echoing the results of state space models and linear f nite impulse-response models whereby the strongest coupling peak occurs in the preceding 1-2 days. It appears that such networks hold promise for the development of accurate and fully data-driven space weather modelling, monitoring and forecast tools.

  15. Volterra network modeling of the nonlinear finite-impulse reponse of the radiation belt flux

    International Nuclear Information System (INIS)

    We show how a general class of spatio-temporal nonlinear impulse-response forecast networks (Volterra networks) can be constructed from a taxonomy of nonlinear autoregressive integrated moving average with exogenous inputs (NAR-MAX) input-output equations, and used to model the evolution of energetic particle f uxes in the Van Allen radiation belts. We present initial results for the nonlinear response of the radiation belts to conditions a month earlier. The essential features of spatio-temporal observations are recovered with the model echoing the results of state space models and linear f nite impulse-response models whereby the strongest coupling peak occurs in the preceding 1-2 days. It appears that such networks hold promise for the development of accurate and fully data-driven space weather modelling, monitoring and forecast tools.

  16. Variability of the Inner Proton Radiation Belt Observed by Van Allen Probes

    Science.gov (United States)

    Li, X.; Selesnick, R.; Baker, D. N.; Jaynes, A. N.; Kanekal, S. G.; Hudson, M. K.; Kress, B. T.

    2015-12-01

    Inner radiation belt protons with kinetic energy above 10 MeV are known to be highly stable, with a maximum intensity near L = 1.5 that varies little evenon solar-cycle time scales. However, for L = 2 and above, more rapid changes occur: (1) protons are trapped during solar particle events, (2) steady intensity changes near L = 2 may result from radial diffusion, (3) for L > 2 there are rapid losses during magnetic storms, and (4) the losses are replenished by albedo neutron decay. New measurements from Van Allen Probes describe each of the last three processes in detail (the first has not yet been observed). These data provide new constraints on theories of trapped proton dynamics and improved empirical estimates of transport coefficients for radiation belt modeling.

  17. Diffusion Simulation of Outer Radiation Belt Electron Dynamics Induced by Superluminous L-O Mode Waves

    Institute of Scientific and Technical Information of China (English)

    XIAO Fu-Liang; HE Zhao-Guo; ZHANG Sai; SU Zhen-Peng; CHEN Liang-Xu

    2011-01-01

    Temporal evolution of outer radiation belt electron dynamics resulting from superluminous L-O mode waves is simulated at L=6.5. Diffusion rates are evaluated and then used as inputs to solve a 2D momentum-pitch-angle diffusion equation, particularly with and without cross diffusion terms. Simulated results demonstrate that phase space density(PSD) of energetic electrons due to L-O mode waves can enhance significantly within 24 h, covering a broader pitch-angle range in the absence of cross terms than that in the presence of cross terms. PSD evolution is also determined by the peak wave frequency, particularly at high kinetic energies. This result indicates that superluminous waves can be a potential candidate responsible for outer radiation belt electron dynamics.

  18. Solar Modulation of Inner Trapped Belt Radiation Flux as a Function of Atmospheric Density

    Science.gov (United States)

    Lodhi, M. A. K.

    2005-01-01

    No simple algorithm seems to exist for calculating proton fluxes and lifetimes in the Earth's inner, trapped radiation belt throughout the solar cycle. Most models of the inner trapped belt in use depend upon AP8 which only describes the radiation environment at solar maximum and solar minimum in Cycle 20. One exception is NOAAPRO which incorporates flight data from the TIROS/NOAA polar orbiting spacecraft. The present study discloses yet another, simple formulation for approximating proton fluxes at any time in a given solar cycle, in particular between solar maximum and solar minimum. It is derived from AP8 using a regression algorithm technique from nuclear physics. From flux and its time integral fluence, one can then approximate dose rate and its time integral dose.

  19. The Electric Field and Waves Instruments on the Radiation Belt Storm Probes Mission

    OpenAIRE

    Wygant, J. R.; Bonnell, J. W.; Goetz, K.; Ergun, R. E.; F. S. Mozer; Bale, S.D.; M. Ludlam; Turin, P.; Harvey, P. R.; Hochmann, R.; Harps, K.; Dalton, G.; McCauley, J.; Rachelson, W.; Gordon, D.

    2013-01-01

    The Electric Fields and Waves (EFW) Instruments on the two Radiation Belt Storm Probe (RBSP) spacecraft (recently renamed the Van Allen Probes) are designed to measure three dimensional quasi-static and low frequency electric fields and waves associated with the major mechanisms responsible for the acceleration of energetic charged particles in the inner magnetosphere of the Earth. For this measurement, the instrument uses two pairs of spherical double probe sensors at the ends of orthogonal ...

  20. Ring Current Density Distribution and Coupling with Radiation Belts Plasma Population

    Science.gov (United States)

    Bogdanova, Yulia; Dunlop, Malcolm; Perry, Chris; Fazakerley, Andrew; Klecker, Berndt; Mouikis, Christopher; Zhang, Qinghe; Shen, Chao

    2015-04-01

    The ring current, a toroidal current system centred at the equatorial plane at geocentric distances between ~2Re and ~9Re, is formed due to the gradient and curvature drifts of the energetic particles trapped in the inner magnetosphere. The radiation belts and ring current are closely related, and it has been shown previously that a subset of the radiation belt population, ions in the medium-energy range, from ~ 10 keV to a few hundreds of keV, contribute the most towards the total ring current energy density, with the O+ ions contribution increasing strongly from 6% to 21% during active times (Daglis et al., 1993). In this work we use unique Cluster observations from the beginning of the mission (2002-2004), with the Cluster satellites often crossing the outer radiation belt and ring current region at L-shell ~ 4 Re. At that time the Cluster tetrahedron geometry was well suited for estimations of the total ring current density and azimuthal current density from the measurements of the magnetic field, using the curlometer technique (Dunlop et al., 2002). We combine the estimations of the current density with the observations of ion and electron populations from the RAPID, CIS and PEACE instruments inside the radiation belts in order to gain additional information on the relative contributions of ions and electrons of different energies towards the ring current strength. Results for a number of cases are presented, including different MLT sectors and levels of geomagnetic activity. The changes in the particle distribution for low and high geomagnetic activity levels will be discussed.

  1. Field-aligned chorus wave spectral power in Earth's outer radiation belt

    OpenAIRE

    H. Breuillard; O. Agapitov; Artemyev, A; E. A. Kronberg; Haaland, S. E.; P. W. Daly; Krasnoselskikh, V. V.; Boscher, D.; Bourdarie, S; Zaliznyak, Y; Rolland, G.

    2015-01-01

    International audience Chorus-type whistler waves are one of the most intense electromagnetic waves generated naturally in the mag-netosphere. These waves have a substantial impact on the radiation belt dynamics as they are thought to contribute to electron acceleration and losses into the ionosphere through resonant wave–particle interaction. Our study is devoted to the determination of chorus wave power distribution on frequency in a wide range of magnetic latitudes, from 0 to 40 •. We u...

  2. A density-temperature description of the outer electron radiation belt during geomagnetic storms

    Energy Technology Data Exchange (ETDEWEB)

    Borovsky, Joseph E [Los Alamos National Laboratory; Cayton, Thomas E [Los Alamos National Laboratory; Denton, Michael H [LANCASTER UNIV

    2009-01-01

    Electron flux measurements from 7 satellites in geosynchronous orbit from 1990-2007 are fit with relativistic bi-Maxwellians, yielding a number density n and temperature T description of the outer electron radiation belt. For 54.5 spacecraft years of measurements the median value ofn is 3.7x10-4 cm-3 and the median value ofT is 142 keY. General statistical properties of n, T, and the 1.1-1.5 MeV flux J are investigated, including local-time and solar-cycle dependencies. Using superposed-epoch analysis triggered on storm onset, the evolution of the outer electron radiation belt through high-speed-steam-driven storms is investigated. The number density decay during the calm before the storm is seen, relativistic-electron dropouts and recoveries from dropout are investigated, and the heating of the outer electron radiation belt during storms is examined. Using four different triggers (SSCs, southward-IMF CME sheaths, southward-IMF magnetic clouds, and minimum Dst), CME-driven storms are analyzed with superposed-epoch techniques. For CME-driven storms an absence of a density decay prior to storm onset is found, the compression of the outer electron radiation belt at time of SSC is analyzed, the number-density increase and temperature decrease during storm main phase is seen, and the increase in density and temperature during storm recovery phase is observed. Differences are found between the density-temperature and the flux descriptions, with more information for analysis being available in the density-temperature description.

  3. Polar PWI and CEPPAD observations of chorus emissions and radiation belt electron acceleration: Four case studies

    Czech Academy of Sciences Publication Activity Database

    Sigsbee, K.; Menietti, J. D.; Santolík, Ondřej; Blake, J. B.

    2008-01-01

    Roč. 70, č. 14 (2008), s. 1774-1788. ISSN 1364-6826 R&D Projects: GA AV ČR IAA301120601 Grant ostatní: NASA (US) NNG05GM52G; NSF(US) 0307319 Institutional research plan: CEZ:AV0Z30420517 Keywords : chorus * outer radiation belt Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.667, year: 2008

  4. Comparative study on earthquake and ground based transmitter induced radiation belt electron precipitation at middle latitudes

    OpenAIRE

    N. F. Sidiropoulos; Anagnostopoulos, G; Rigas, V.

    2011-01-01

    We examined (peak-to-background flux ratio p/b > 20) energetic electron bursts in the presence of VLF activity, as observed from the DEMETER satellite at low altitudes (~700 km). Our statistical analysis of measurements during two 6-month periods suggests that: (a) the powerful transmitter NWC causes the strongest effects on the inner radiation belts in comparison with other ground-based VLF transmitters, (b) the NWC transmitter was responsible for only ~1.5 % of total elect...

  5. Survey of ELF-VLF plasma waves in outer radiation belt observed by Cluster STAFF-SA experiment

    Directory of Open Access Journals (Sweden)

    D. Pokhotelov

    2008-10-01

    Full Text Available Various types of plasma waves have profound effects on acceleration and scattering of radiation belt particles. For the purposes of radiation belt modeling it is necessary to know statistical distributions of plasma wave parameters. This paper analyzes four years of plasma wave observations in the Earth's outer radiation belt obtained by the STAFF-SA experiment on board Cluster spacecraft. Statistical distributions of spectral density of different plasma waves observed in ELF-VLF range (chorus, plasmaspheric hiss, magnetosonic waves are presented as a function of magnetospheric coordinates and geomagnetic activity indices. Comparison with other spacecraft studies supports some earlier conclusions about the distribution of chorus and hiss waves and helps to remove the long-term controversy regarding the distribution of equatorial magnetosonic waves. This study represents a step towards the development of multi-spacecraft database of plasma wave activity in radiation belts.

  6. Saturn Neutron Exosphere as Source for Inner and Innermost Radiation Belts

    Science.gov (United States)

    Cooper, John; Lipatov, Alexander; Sittler, Edward; Sturner, Steven

    2011-01-01

    Energetic proton and electron measurements by the ongoing Cassini orbiter mission are expanding our knowledge of the highest energy components of the Saturn magnetosphere in the inner radiation belt region after the initial discoveries of these belts by the Pioneer 11 and Voyager 2 missions. Saturn has a neutron exosphere that extends throughout the magnetosphere from the cosmic ray albedo neutron source at the planetary main rings and atmosphere. The neutrons emitted from these sources at energies respectively above 4 and 8 eV escape the Saturn system, while those at lower energies are gravitationally bound. The neutrons undergo beta decay in average times of about 1000 seconds to provide distributed sources of protons and electrons throughout Saturn's magnetosphere with highest injection rates close to the Saturn and ring sources. The competing radiation belt source for energetic electrons is rapid inward diffusion and acceleration of electrons from the middle magnetosphere and beyond. Minimal losses during diffusive transport across the moon orbits, e.g. of Mimas and Enceladus, and local time asymmetries in electron intensity, suggest that drift resonance effects preferentially boost the diffusion rates of electrons from both sources. Energy dependences of longitudinal gradient-curvature drift speeds relative to the icy moons are likely responsible for hemispheric differences (e.g., Mimas, Tethys) in composition and thermal properties as at least partly produced by radiolytic processes. A continuing mystery is the similar radial profiles of lower energy (neutron decay, but perhaps alternatively from atmospheric albedo, or else all protons from diverse distributed sources are similarly affected by losses at the moon' orbits, e.g. because the proton diffusion rates are extremely low. Enceladus cryovolcanism, and radiolytic processing elsewhere on the icy moon and ring surfaces, are additional sources of protons via ionization and charge exchange from breakup of

  7. Characterizing magnetopause shadowing effects on the radiation belt's dynamic: modelling and comparison to observations.

    Science.gov (United States)

    Maget, Vincent; Bourdarie, Sebastien; Boscher, Daniel

    2014-05-01

    The dynamic of the Earth's electron radiation belts are mainly governed by internal processes enhanced during period of electromagnetic disturbances. In the framework of the EU-FP7 SPACECAST project, the modelling of many of them has been improved and implemented into the ONERA Salammbô code (radial diffusion, wave-particle interactions, and boundary conditions). Furthermore, the modelling of drop-outs has also been investigated. Such a global magnetospheric process can drastically modify the shape of the outer radiation belts during magnetic storms. In the present talk, we aim at showing how magnetopause shadowing primarily contributes to drop-outs of > 300 keV electrons in the outer radiation belt. In particular, the impact of the combination of all the improvements conducted during the SPACECAST project are highlighted and compared to recent data. SPACECAST has received fundings from the European Community's Seventh Framework Programme (FP7-SPACE-.2010-1, SP1 Cooperation, Collaborative project) under grant agreement n262468. This paper reflects only the authors' views and the European Union is not liable for any use that may be made of the information contained therein.

  8. Examining the specific entropy (density of adiabatic invariants) of the outer electron radiation belt

    Energy Technology Data Exchange (ETDEWEB)

    Borovsky, Joseph E [Los Alamos National Laboratory; Denton, Michael H [LANCASTER UNIV

    2008-01-01

    Using temperature and number-density measurements of the energetic-electron population from multiple spacecraft in geosynchronous orbit, the specific entropy S = T/n{sup 2/3} of the outer electron radiation belt is calculated. Then 955,527 half-hour-long data intervals are statistically analyzed. Local-time and solar-cycle variations in S are examined. The median value of the specific entropy (2.8 x 10{sup 7} eVcm{sup 2}) is much larger than the specific entropy of other particle populations in and around the magnetosphere. The evolution of the specific entropy through high-speed-stream-driven geomagnetic storms and through magnetic-cloud-driven geomagnetic storms is studied using superposed-epoch analysis. For high-speed-stream-driven storms, systematic variations in the entropy associated with electron loss and gain and with radiation-belt heating are observed in the various storm phases. For magnetic-cloud-driven storms, multiple trigger choices for the data superpositions reveal the effects of interplanetary shock arrival, sheath driving, cloud driving, and recovery phase. The specific entropy S = T/n{sup 2/3} is algebraically expressed in terms of the first and second adiabatic invariants of the electrons: this allows a relativistic expression for S in terms of T and n to be derived. For the outer electron radiation belt at geosynchronous orbit, the relativistic corrections to the specific entropy expression are -15%.

  9. An improved forecast system for relativistic electrons in Earth's outer radiation belt

    Science.gov (United States)

    Turner, D. L.; Li, X.

    2010-12-01

    As society becomes more dependent on satellite systems for navigation, communication, defense, and weather prediction, accurate forecasts of Earth's outer radiation belt electrons become ever more important to help mitigate risk to spacecraft in orbits that go through this hazardous region. Currently, outer radiation belt forecast models are only for daily-averaged fluxes (or fluence) at geosynchronous orbit (GEO), yet due to the nature of Earth's asymmetric magnetosphere, with its compressed dayside and stretched nightside, a spacecraft in GEO encounters a wide range of fluxes at different local times. Also, many of the existing forecasts are single-point dependent; that is, they rely on one spacecraft at the L1 point in the Sun-Earth system for upstream measurements of the solar wind. Here, we introduce a recently developed system of forecast models for outer radiation belt electrons that are currently running in real-time. This system includes several different forecast models, including one that is independent of solar wind measurements. It also incorporates a new technique to forecast fluxes at each local hour around GEO, and an innovative method to extend several of the forecasts out to +6 days. We conclude with a discussion of how data reanalysis techniques can be incorporated to extend forecasts to other L-shells.

  10. Determining the spectra of radiation belt electron losses: Fitting DEMETER electron flux observations for typical and storm times

    Science.gov (United States)

    Whittaker, Ian C.; Gamble, Rory J.; Rodger, Craig J.; Clilverd, Mark A.; Sauvaud, Jean-André

    2013-12-01

    The energy spectra of energetic electron precipitation from the radiation belts are studied in order to improve our understanding of the influence of radiation belt processes. The Detection of Electromagnetic Emissions Transmitted from Earthquake Regions (DEMETER) microsatellite electron flux instrument is comparatively unusual in that it has very high energy resolution (128 channels with 17.9 keV widths in normal survey mode), which lends itself to this type of spectral analysis. Here electron spectra from DEMETER have been analyzed from all six years of its operation, and three fit types (power law, exponential, and kappa-type) have been applied to the precipitating flux observations. We show that the power law fit consistently provides the best representation of the flux and that the kappa-type is rarely valid. We also provide estimated uncertainties in the flux for this instrument as a function of energy. Average power law gradients for nontrapped particles have been determined for geomagnetically nondisturbed periods to get a typical global behavior of the spectra in the inner radiation belt, slot region, and outer radiation belt. Power law spectral gradients in the outer belt are typically -2.5 during quiet periods, changing to a softer spectrum of ˜-3.5 during geomagnetic storms. The inner belt does the opposite, hardening from -4 during quiet times to ˜-3 during storms. Typical outer belt e-folding values are ˜200 keV, dropping to ˜150 keV during geomagnetic storms, while the inner belt e-folding values change from ˜120 keV to >200 keV. Analysis of geomagnetic storm periods show that the precipitating flux enhancements evident from such storms take approximately 13 days to return to normal values for the outer belt and slot region and approximately 10 days for the inner belt.

  11. On the generation of large amplitude spiky solitons by ultralow frequency earthquake emission in the Van Allen radiation belt

    International Nuclear Information System (INIS)

    The parametric coupling between earthquake emitted circularly polarized electromagnetic radiation and ponderomotively driven ion-acoustic perturbations in the Van Allen radiation belt is considered. A cubic nonlinear Schroedinger equation for the modulated radiation envelope is derived, and then solved analytically. For ultralow frequency earthquake emissions large amplitude spiky supersonic bright solitons or subsonic dark solitons are found to be generated in the Van Allen radiation belt, detection of which can be a tool for the prediction of a massive earthquake may be followed later

  12. Radial dependence of ionization losses of protons of the Earth's radiation belts

    International Nuclear Information System (INIS)

    Coulomb losses and charge exchange of protons are considered in detail. On the basis of modern models of the plasmasphere and the exosphere, the radial dependences of the rates of ionization losses of protons, with μ from 0.3 to 10 keV nT-1, of the Earth's radiation belts near the equatorial plane are calculated for quiet periods. For calculation of Coulomb losses of protons we used data of ISEE-1 satellite (protons with energy from 24 to 2081 keV) on L from 3 to 9, data of Explorer-45 satellite (protons with energy from 78.6 to 872 keV) on L from 3 to 5 and data of CRRES satellite (protons with energy from 1 to 100 MeV) on L ≤ 3 (L is the McIlwain parameter). It is shown that with decreasing L the rate of ionization losses of protons of the radiation belts is reduced; for protons with μ > 1.2 keV nT-1 in a narrow region (ΔL ∝ 0.5) in the district of plasmapause in this dependence may form a local minimum of the rate. We found that the dependence from μ of the boundary on L between Coulomb losses and charge exchange of the trapped protons with hydrogen atoms is well approximated by the function Lb = 4.71μ0.32, where [μ] = keV nT-1. Coulomb losses dominate at L < Lb(μ), and at L > Lb(μ) dominates charge exchange of protons. We found the effect of subtracting the Coulomb losses from the charge exchange of protons of the radiation belts at low μ and L, which can simulate a local source of particles.

  13. Radial dependence of ionization losses of protons of the Earth's radiation belts

    Energy Technology Data Exchange (ETDEWEB)

    Kovtyukh, A.S. [Moscow State Univ. (Russian Federation). Skobeltsyn Inst. of Nuclear Phyiscs

    2016-04-01

    Coulomb losses and charge exchange of protons are considered in detail. On the basis of modern models of the plasmasphere and the exosphere, the radial dependences of the rates of ionization losses of protons, with μ from 0.3 to 10 keV nT{sup -1}, of the Earth's radiation belts near the equatorial plane are calculated for quiet periods. For calculation of Coulomb losses of protons we used data of ISEE-1 satellite (protons with energy from 24 to 2081 keV) on L from 3 to 9, data of Explorer-45 satellite (protons with energy from 78.6 to 872 keV) on L from 3 to 5 and data of CRRES satellite (protons with energy from 1 to 100 MeV) on L ≤ 3 (L is the McIlwain parameter). It is shown that with decreasing L the rate of ionization losses of protons of the radiation belts is reduced; for protons with μ > 1.2 keV nT{sup -1} in a narrow region (ΔL ∝ 0.5) in the district of plasmapause in this dependence may form a local minimum of the rate. We found that the dependence from μ of the boundary on L between Coulomb losses and charge exchange of the trapped protons with hydrogen atoms is well approximated by the function L{sub b} = 4.71μ{sup 0.32}, where [μ] = keV nT{sup -1}. Coulomb losses dominate at L < L{sub b}(μ), and at L > L{sub b}(μ) dominates charge exchange of protons. We found the effect of subtracting the Coulomb losses from the charge exchange of protons of the radiation belts at low μ and L, which can simulate a local source of particles.

  14. Radiation belt electron precipitation and its ionospheric effects at middle latitudes

    International Nuclear Information System (INIS)

    The role of radiation belt electron precipitation into the Earth's atmosphere at middle geomagnetic latitudes is studied. First, the process of pitch angle scattering of energetic electrons in the radiation belts is modeled, and the flux angular distributions are obtained for all pitch angles, including the atmospheric bounce loss cone. This determines the angular distribution of the precipitating fluxes. Secondly, the interaction of these fluxes with the ambient atmospheric constituents is simulated, using the Fokker-Planck method; and the rate of energy deposition in the atmosphere is calculated at any given height. This gives rise to a significant rate of ion pair production in the lower ionosphere. Thirdly, the influence of this precipitation induced ionization on the structure and composition of the ionospheric D-region is modeled. Two specific classes of electron precipitation are studied; one is the quiet time ''drizzle'' occurring in the absence of geomagnetic disturbances; the second is the storm-time precipitation during the recovery phase of major geomagnetic storms with its substantial impact on the lower ionosphere. Computations are furthermore carried out for geomagnetically quiet times, and the results indicate that the electron precipitation can provide the dominant nocturnal ionization source for the D-region in a narrow belt of geomagnetic latitudes corresponding to the inner edge of the outer radiation zone (L approximately 4 to 5; Λ approximately 600 to 650) with ion pair production rates typically between 0.1 and 1 ion pair cm-3 sec-1 from about 60 to 90 kilometers at L = 5. (U.S.)

  15. Simulation of Radiation Belt Precipitation During the March 17, 2013 Storm

    Science.gov (United States)

    Brito, T. V.; Hudson, M. K.; Paral, J.

    2014-12-01

    Balloon-borne instruments detecting radiation belt precipitation frequently observe oscillations in the mHZ frequency range. Several balloon missions measuring electron precipitation near the poles in the 100 keV to 2.5 MeV energy range, including the MAXIS, MINIS, and most recently the BARREL campaign, have observed this modulation at ULF wave frequencies (Clilverd et al., 2007; Millan et al., 2011). However, ULF waves in the magnetosphere, commonly associated with oscillations in solar wind dynamic pressure on the dayside and with Kelvin-Helmhotz instabilities in the flanks, are seldom directly linked to increases in electron precipitation since their oscillation periods are much larger than the gyroperiod and the bounce period of radiation belt electrons. It has been conjectured that ULF oscillations in the magnetosphere may modulate EMIC wave growth rates. EMIC waves, in turn, have long been associated with energetic electron precipitation, since they can cause pitch angle scattering of these particles, thus lowering their mirror points (Miyoshi et al., 2008; Carson et al., 2013). This would explain the ULF modulation of MeV electrons seen by the balloon instruments. However, test particle simulations show that another hypothesis is possible (Brito et al., 2012). 3D simulations of radiation belt electrons were performed to investigate the effect of ULF waves on precipitation. The simulations track the behavior of energetic electrons near the loss cone, using guiding center techniques, coupled with an MHD simulation of the magnetosphere, using the LFM code, during a CME-shock event on March 17, 2013. Results indicate that ULF modulation of precipitation occurs even without the presence of VLF-type waves, which are not resolved in the MHD simulation.

  16. The virtual radiation belt observatory (VIRBO) and the future of the VxO environment

    International Nuclear Information System (INIS)

    Complete text of publication follows. This presentation will cover two topics: (1) the data products available and exposed through ViRBO and (2) our perspectives and predictions about how the rapidly evolving virtual observatory environment will facilitate research that requires the integration of data and model results from many different sources. ViRBO is a virtual observatory which allows access to and use of data and tools for radiation belt scientists. Data sets include data from the SAMPEX, GOES, POES, LANL GEO, Polar, and GPS satellites. A number of new data sets, not previously available, are available from the HEO-1, HEO-3, CRRES, SCATHA, OV1-19, ICO, S3-3, and OV3-3 spacecraft. Scientist-contributed model data include that of the radiation belt content index, a geostationary plasma density and temperature reanalysis data set, and a four-decade-long set of time series of key inputs to modern empirical magnetic field models. In collaboration with the Geospace Environment Modeling Radiation Belt Climatology Focus Group, ViRBO has synthesized and created a data set containing a large collection of data relevant to climatological and statistical studies. Data are served in a number of ways, including from a basic FTP site and an OPeNDAP server. Visualizations of data are created using Autoplot, which is a spin-off project of ViRBO. Metadata search, editing, and access are provided through VxOware, another spin-off project of ViRBO that is in preparation for general release.

  17. Alternatives to accuracy and bias metrics based on percentage errors for radiation belt modeling applications

    Energy Technology Data Exchange (ETDEWEB)

    Morley, Steven Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-07-01

    This report reviews existing literature describing forecast accuracy metrics, concentrating on those based on relative errors and percentage errors. We then review how the most common of these metrics, the mean absolute percentage error (MAPE), has been applied in recent radiation belt modeling literature. Finally, we describe metrics based on the ratios of predicted to observed values (the accuracy ratio) that address the drawbacks inherent in using MAPE. Specifically, we define and recommend the median log accuracy ratio as a measure of bias and the median symmetric accuracy as a measure of accuracy.

  18. High-energy electrons in the inner radiation belt of the earth

    Science.gov (United States)

    Basilova, R. N.; Gusev, A. A.; Pugacheva, G. I.; Titenkov, A. F.

    1982-08-01

    Measurements of electron fluxes with energies greater than 40 MeV obtained by Kosmos 490, Salut 6, and Interkosmos 17 satellites at heights of 270-500 km in the Brazilian anomaly region are discussed. The observed electron flux is explained in terms of the decomposition of pi meson, produced by the interaction between high-energy protons (0.35-1 GeV) of the inner radiation belt and atoms of the residual atmosphere. A formula describing the electron flux is presented.

  19. Alternatives to accuracy and bias metrics based on percentage errors for radiation belt modeling applications

    Energy Technology Data Exchange (ETDEWEB)

    Morley, Steven Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-07-01

    This report reviews existing literature describing forecast accuracy metrics, concentrating on those based on relative errors and percentage errors. We then review how the most common of these metrics, the mean absolute percentage error (MAPE), has been applied in recent radiation belt modeling literature. Finally, we describe metrics based on the ratios of predicted to observed values (the accuracy ratio) that address the drawbacks inherent in using MAPE. Specifically we define and recommend the median log accuracy ratio as a measure of bias and the median symmetric accuracy as a measure of accuracy.

  20. Conjugate In-situ and Incoherent Scatter Radar Observations of Radiation Belt Loss Mechanisms.

    Science.gov (United States)

    Kaeppler, S. R.; Jaynes, A. N.; Sanchez, E. R.; Nicolls, M. J.; Varney, R. H.; Marshall, R. A.

    2015-12-01

    We present results from conjugate observations between the Radiation Belt Storms Probe (RBSP) and the Poker Flat Incoherent Scatter Radar (PFISR) of energetic radiation belt precipitation. A key objective of the RBSP mission is to understand loss mechanisms of energetic particles from the radiation belt. The relative contribution from plasma waves (e.g., EMIC, hiss, chorus, and etc.) that pitch angle scatter particles into the loss cone remains an open scientific question. Rigorous experimental validation of these mechanisms is difficult to achieve because nearly simultaneous conjugate observations of in-situ pitch angle scattering and precipitation into the atmosphere are required. One ground-based signature of energetic precipitation is enhanced ionization and electron density at D-region altitudes. Incoherent scatter radar is a powerful remote sensing technique that is sensitive to electron density enhancements. By measuring the altitude profiles of ionization we infer the flux of particles precipitating into the atmosphere. PFISR observations show frequent occurrence of D-region ionization during both quiet-time and storm-time conditions. We present results from two events when the foot-points of the RBSP satellite were within 500 km of PFISR: a quiet-time event on January 13, 2015, and a storm-time event on April 16, 2015. PFISR observations of the D-region ionization signatures are presented, along with simultaneous conjugate RBSP observations of the magnetic field, electric field, and electron flux. Plasma waves are identified using the electric and magnetic field data, and evaluated as possible pitch angle scattering mechanisms. A direct comparison between the measured fluxes and loss cone fluxes predicted by theoretical wave-particle diffusion rates into the loss cone is used to test the validity of particle loss mechanisms predicted by the different theories. Preliminary results are presented of PFISR inversions of the D-region ionization to quantify the

  1. Estimates of trapped radiation encountered on low-thrust trajectories through the Van Allen belts

    Science.gov (United States)

    Karp, I. M.

    1973-01-01

    Estimates were made of the number of trapped protons and electrons encountered by vehicles on low-thrust trajectories through the Van Allen belts. The estimates serve as a first step in assessing whether these radiations present a problem to on-board sensitive components and payload. The integrated proton spectra and electron spectra are presented for the case of a trajectory described by a vehicle with a constant-thrust acceleration A sub c equal to 0.001 meter/sq sec. This value of acceleration corresponds to a trip time of about 54 days from low earth orbit to synchronous orbit. It is shown that the time spent in the belts and hence the radiation encountered vary nearly inversely with the value of thrust acceleration. Thus, the integrated spectral values presented for the case of A sub c = 0.001 meter/sq sec can be generalized for any other value of thrust acceleration by multiplying them by the factor 0.001/A sub c.

  2. Accaleration of Electrons of the Outer Electron Radiation Belt and Auroral Oval Dynamics

    Science.gov (United States)

    Antonova, Elizaveta; Ovchinnikov, Ilya; Riazantseva, Maria; Znatkova, Svetlana; Pulinets, Maria; Vorobjev, Viachislav; Yagodkina, Oksana; Stepanova, Marina

    2016-07-01

    We summarize the results of experimental observations demonstrating the role of auroral processes in the formation of the outer electron radiation belt and magnetic field distortion during magnetic storms. We show that the auroral oval does not mapped to the plasma sheet proper (region with magnetic field lines stretched in the tailward direction). It is mapped to the surrounding the Earth plasma ring in which transverse currents are closed inside the magnetosphere. Such currents constitute the high latitude continuation of the ordinary ring current. Mapping of the auroral oval to the region of high latitude continuation of the ordinary ring current explains the ring like shape of the auroral oval with finite thickness near noon and auroral oval dynamics during magnetic storms. The auroral oval shift to low latitudes during storms. The development of the ring current produce great distortion of the Earth's magnetic field and corresponding adiabatic variations of relativistic electron fluxes. Development of the asymmetric ring current produce the dawn-dusk asymmetry of such fluxes. We analyze main features of the observed processes including formation of sharp plasma pressure profiles during storms. The nature of observed pressure peak is analyzed. It is shown that the observed sharp pressure peak is directly connected with the creation of the seed population of relativistic electrons. The possibility to predict the position of new radiation belt during recovery phase of the magnetic storm using data of low orbiting and ground based observations is demonstrated.

  3. An integrated artificial neural networks approach for predicting global radiation

    International Nuclear Information System (INIS)

    This article presents an integrated artificial neural network (ANN) approach for predicting solar global radiation by climatological variables. The integrated ANN trains and tests data with multi layer perceptron (MLP) approach which has the lowest mean absolute percentage error (MAPE). The proposed approach is particularly useful for locations where no available measurement equipment. Also, it considers all related climatological and meteorological parameters as input variables. To show the applicability and superiority of the integrated ANN approach, monthly data were collected for 6 years (1995-2000) in six nominal cities in Iran. Separate model for each city is considered and the quantity of solar global radiation in each city is calculated. Furthermore an integrated ANN model has been introduced for prediction of solar global radiation. The acquired results of the integrated model have shown high accuracy of about 94%. The results of the integrated model have been compared with traditional angstrom's model to show its considerable accuracy. Therefore, the proposed approach can be used as an efficient tool for prediction of solar radiation in the remote and rural locations with no direct measurement equipment.

  4. Investigation of the solar UV/EUV related changes in the Jovian radiation belt and thermosphere

    Science.gov (United States)

    Kita, H.; Misawa, H.; Bhardwaj, A.; Tsuchiya, F.; Tao, C.; Sakanoi, T.; Miyoshi, Y.; Kasaba, Y.; Morioka, A.

    2013-09-01

    In order to investigate atmospheric heating effect by the solar UV/EUV on the Jovian Radiation Belt, we made coordinated observations using a radio interferometer and an infrared telescope. The total flux density of Jovian Synchrotron Radiation (JSR) increased from 6th Nov to 13th Nov in 2011 by about 5%, corresponding to the solar UV/EUV variations. The infrared H3+ emission also increased from 7th Nov. to 12th Nov. by 20-30%. These support a theoretical expectation that solar UV/EUV heating for the Jovian thermosphere drives neutral wind perturbations, then the induced dynamo electric field increases the total radio flux density. On the other hand, radio images showed that the equatorial emission peak moved outward by about 0.2 Jovian radii. These observation results showed that the variation of JSR at this time was caused by not global but non-uniform enhancement of radial diffusion.

  5. Dynamics of magnetically trapped particles foundations of the physics of radiation belts and space plasmas

    CERN Document Server

    Roederer, Juan G

    2014-01-01

    This book is a new edition of Roederer’s classic Dynamics of Geomagnetically Trapped Radiation, updated and considerably expanded. The main objective is to describe the dynamic properties of magnetically trapped particles in planetary radiation belts and plasmas and explain the physical processes involved from the theoretical point of view. The approach is to examine in detail the orbital and adiabatic motion of individual particles in typical configurations of magnetic and electric fields in the magnetosphere and, from there, derive basic features of the particles’ collective “macroscopic” behavior in general planetary environments. Emphasis is not on the “what” but on the “why” of particle phenomena in near-earth space, providing a solid and clear understanding of the principal basic physical mechanisms and dynamic processes involved. The book will also serve as an introduction to general space plasma physics, with abundant basic examples to illustrate and explain the physical origin of diff...

  6. Wave energy budget analysis in the Earth's radiation belts uncovers a missing energy

    Science.gov (United States)

    Artemyev, A. V.; Agapitov, O. V.; Mourenas, D.; Krasnoselskikh, V. V.; Mozer, F. S.

    2015-05-01

    Whistler-mode emissions are important electromagnetic waves pervasive in the Earth's magnetosphere, where they continuously remove or energize electrons trapped by the geomagnetic field, controlling radiation hazards to satellites and astronauts and the upper-atmosphere ionization or chemical composition. Here, we report an analysis of 10-year Cluster data, statistically evaluating the full wave energy budget in the Earth's magnetosphere, revealing that a significant fraction of the energy corresponds to hitherto generally neglected very oblique waves. Such waves, with 10 times smaller magnetic power than parallel waves, typically have similar total energy. Moreover, they carry up to 80% of the wave energy involved in wave-particle resonant interactions. It implies that electron heating and precipitation into the atmosphere may have been significantly under/over-valued in past studies considering only conventional quasi-parallel waves. Very oblique waves may turn out to be a crucial agent of energy redistribution in the Earth's radiation belts, controlled by solar activity.

  7. Study on geomagnetic storms driving motion of 0.1-2 MeV radiation belt electrons

    Science.gov (United States)

    Zhang, Zhenxia; Li, Xinqiao

    2016-08-01

    Using more than five years' worth of data observed by the Instrument for the Detection of Particles (IDP) spectrometer onboard the Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions (DEMETER) satellite, we studied the motion characteristics of energetic electrons in different regions, i.e., the inner radiation belt, the outer radiation belt, and the slot region in geomagnetic storms. We investigated the flux change of 0.1-2.4 MeV electrons and the energy change of 0.1-1.0 MeV electrons in these different regions. By cross correlation analysis, we came to the following conclusions. First, when Dst geomagnetic storms on electrons are not distinguished significantly between in the day and night, and independent of the timing of the events. For storms with -50 geomagnetic storms is opposite in the inner and outer radiation belts. The proportion of electrons accelerated to relativistic energies is greater in the outer radiation and slot regions, while the ejection energetic electrons are more concentrated in the low energy region of the inner radiation belt. This phenomenon reflects the different electron injection mechanisms and accelerating processes responsible for spectral index variations in different L regions during geomagnetic storms.

  8. Parametric validations of analytical lifetime estimates for radiation belt electron diffusion by whistler waves

    Directory of Open Access Journals (Sweden)

    A. V. Artemyev

    2013-04-01

    Full Text Available The lifetimes of electrons trapped in Earth's radiation belts can be calculated from quasi-linear pitch-angle diffusion by whistler-mode waves, provided that their frequency spectrum is broad enough and/or their average amplitude is not too large. Extensive comparisons between improved analytical lifetime estimates and full numerical calculations have been performed in a broad parameter range representative of a large part of the magnetosphere from L ~ 2 to 6. The effects of observed very oblique whistler waves are taken into account in both numerical and analytical calculations. Analytical lifetimes (and pitch-angle diffusion coefficients are found to be in good agreement with full numerical calculations based on CRRES and Cluster hiss and lightning-generated wave measurements inside the plasmasphere and Cluster lower-band chorus waves measurements in the outer belt for electron energies ranging from 100 keV to 5 MeV. Comparisons with lifetimes recently obtained from electron flux measurements on SAMPEX, SCATHA, SAC-C and DEMETER also show reasonable agreement.

  9. Parametric validations of analytical lifetime estimates for radiation belt electron diffusion by whistler waves

    International Nuclear Information System (INIS)

    The lifetimes of electrons trapped in Earth's radiation belts can be calculated from quasi-linear pitch-angle diffusion by whistler-mode waves, provided that their frequency spectrum is broad enough and/or their average amplitude is not too large. Extensive comparisons between improved analytical lifetime estimates and full numerical calculations have been performed in a broad parameter range representative of a large part of the magnetosphere from L ∼ 2 to 6. The effects of observed very oblique whistler waves are taken into account in both numerical and analytical calculations. Analytical lifetimes (and pitch-angle diffusion coefficients) are found to be in good agreement with full numerical calculations based on CRRES and Cluster hiss and lightning-generated wave measurements inside the plasmasphere and Cluster lower-band chorus waves measurements in the outer belt for electron energies ranging from 100 keV to 5 MeV. Comparisons with lifetimes recently obtained from electron flux measurements on SAMPEX, SCATHA, SAC-C and DEMETER also show reasonable agreement. (authors)

  10. Study on geomagnetic storms driving motion of 0.1-2 MeV radiation belt electrons

    Science.gov (United States)

    Zhang, Zhenxia; Li, Xinqiao

    2016-08-01

    Using more than five years' worth of data observed by the Instrument for the Detection of Particles (IDP) spectrometer onboard the Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions (DEMETER) satellite, we studied the motion characteristics of energetic electrons in different regions, i.e., the inner radiation belt, the outer radiation belt, and the slot region in geomagnetic storms. We investigated the flux change of 0.1-2.4 MeV electrons and the energy change of 0.1-1.0 MeV electrons in these different regions. By cross correlation analysis, we came to the following conclusions. First, when Dst < -50, the correlation coefficient (c.c.) of the electron flux and Dst index ranges from -0.63 to -0.86, and the enhancement of the electron flux generally occurs during the storm's main and recovery phases. Second, the storms greatly influence the lower energy region of the electron energy spectrum in the inner radiation belt, while the enhancement in the higher energy region is more significant in the outer radiation belt and the slot region. Third, the effects of geomagnetic storms on electrons are not distinguished significantly between in the day and night, and independent of the timing of the events. For storms with -50 < Dst < -30, there is a negative correlation of -0.51 to -0.57 between the Dst index and the electron flux in the outer radiation belt. Our analysis suggests that strong storms cause energetic electron ejections across a wide range, and the ejection level is affected by the storm intensity. Furthermore, the electron energy region influenced by the strong geomagnetic storms is opposite in the inner and outer radiation belts. The proportion of electrons accelerated to relativistic energies is greater in the outer radiation and slot regions, while the ejection energetic electrons are more concentrated in the low energy region of the inner radiation belt. This phenomenon reflects the different electron injection mechanisms and

  11. Storm-induced energization of radiation belt electrons: Effect of wave obliquity

    International Nuclear Information System (INIS)

    New Cluster statistics allow us to determine for the first time the variations of both the obliquity and intensity of lower-band chorus waves as functions of latitude and geomagnetic activity near L ∼ 5. The portion of wave power in very oblique waves decreases during highly disturbed periods, consistent with increased Landau damping by inward-penetrating suprathermal electrons. Simple analytical considerations as well as full numerical calculations of quasi-linear diffusion rates demonstrate that early-time electron acceleration occurs in a regime of loss-limited energization. In this regime, the average wave obliquity plays a critical role in mitigating lifetime reduction as wave intensity increases with geomagnetic activity, suggesting that much larger energization levels should be reached during the early recovery phase of storms than during quiet time or moderate disturbances, the latter corresponding to stronger losses. These new effects should be included in realistic radiation belt simulations. (authors)

  12. Precipitation of radiation belt electrons by EMIC waves, observed from ground and space

    Energy Technology Data Exchange (ETDEWEB)

    Jordanova, Vania K [Los Alamos National Laboratory; Miyoski, Y [NAGOYA UNIV; Sakaguchi, K [NAGOYA UNIV; Shiokawa, K [NAGOYA UNIV; Evans, D S [NOAA, BOULDER; Albert, Jay [AFRL; Connors, M [UNIV OF ATHABASCA

    2008-01-01

    We show evidence that left-hand polarised electromagnetic ion cyclotron (EMIC) plasma waves can cause the loss of relativistic electrons into the atmosphere. Our unique set of ground and satellite observations shows coincident precipitation of ions with energies of tens of keY and of relativistic electrons into an isolated proton aurora. The coincident precipitation was produced by wave-particle interactions with EMIC waves near the plasmapause. The estimation of pitch angle diffusion coefficients supports that the observed EMIC waves caused coincident precipitation ofboth ions and relativistic electrons. This study clarifies that ions with energies of tens of ke V affect the evolution of relativistic electrons in the radiation belts via cyclotron resonance with EMIC waves, an effect that was first theoretically predicted in the early 1970's.

  13. Accurately specifying storm-time ULF wave radial diffusion in the radiation belts

    CERN Document Server

    Dimitrakoudis, Stavros; Balasis, Georgios; Papadimitriou, Constantinos; Anastasiadis, Anastasios; Daglis, Ioannis A

    2015-01-01

    Ultra-low frequency (ULF) waves can contribute to the transport, acceleration and loss of electrons in the radiation belts through inward and outward diffusion. However, the most appropriate parameters to use to specify the ULF wave diffusion rates are unknown. Empirical representations of diffusion coefficients often use Kp; however, specifications using ULF wave power offer an improved physics-based approach. We use 11 years of ground-based magnetometer array measurements to statistically parameterise the ULF wave power with Kp, solar wind speed, solar wind dynamic pressure and Dst. We find Kp is the best single parameter to specify the statistical ULF wave power driving radial diffusion. Significantly, remarkable high energy tails exist in the ULF wave power distributions when expressed as a function of Dst. Two parameter ULF wave power specifications using Dst as well as Kp provide a better statistical representation of storm-time radial diffusion than any single variable alone.

  14. Evidence for solar wind origin of energetic heavy ions in the earth's radiation belt

    Science.gov (United States)

    Hovestadt, D.; Klecker, B.; Scholer, M.; Gloeckler, G.; Ipavich, F. M.; Fan, C. Y.; Fisk, L. A.; Ogallagher, J. J.

    1978-01-01

    Analysis of data from our energetic ion composition experiment on ISEE-1 has revealed the presence of substantial fluxes of carbon, oxygen, and heavier ions above 400 keV/nucleon at L values between approximately 2.5 and 4 earth radii. The measured C/O ratio varies systematically from 1.3 at 450 keV/nucleon to 4.1 at 1.3 MeV/nucleon, and no iron is observed above 200 keV/nucleon. These results provide strong evidence for a solar wind origin for energetic ions in the outer radiation belt. The absence of iron and the increase of the carbon-to-oxygen ratio with energy suggest that the condition for the validity of the first adiabatic invariant may have a strong influence on the trapping of these particles.

  15. Hiss induced radiation belt electron loss timescales in the plasmasphere based on ray tracings of wave propagation angle

    Science.gov (United States)

    Zhou, C.; Ni, B.; Li, W.; Bortnik, J.; Gu, X.; Zhao, Z.

    2015-12-01

    Plasmaspheric hiss plays an important role in driving resonant scattering losses of radiation belt electrons and thereby largely controls the lifetimes of electrons in the plasmasphere. Besides the spectral information of waves, an accurate investigation of hiss induced radiation belt electron loss timescales requires the details of wave normal angle distribution during propagation along the field line, which however is difficult to obtain directly from in situ measurements but can be reasonably evaluated from ray tracing of hiss propagation on basis of reasonable setups of background field and plasma density. By assuming a nominal and suitable plasmapause location at L = 4.5, we report the ray tracing results of hiss wave propagation angles for various hiss wave frequencies at various L-shells in the plasmasphere. Subsequently, we construct the improved model of hiss wave normal angle distribution with dependence on both wave frequency, magnetic latitude and L-shell, which is used to compute the quasi-linear bounce-averaged rates of electron scattering due to plasmaspheric hiss and perform the pure pitch angle diffusion simulations. Hiss induced radiation belt electron loss timescales are then determined from the simulated temporal evolution of electron fluxes after reaching the equilibrium state, as a function of electron kinetic energy and L-shell, which is of importance for incorporation into future simulations of the radiation belt electron dynamics under various geomagnetic conditions to comprehend the exact contribution of plasmaspheric hiss.

  16. Radiation belt electron acceleration during the 17 March 2015 geomagnetic storm: Observations and simulations

    Science.gov (United States)

    Li, W.; Ma, Q.; Thorne, R. M.; Bortnik, J.; Zhang, X.-J.; Li, J.; Baker, D. N.; Reeves, G. D.; Spence, H. E.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Blake, J. B.; Fennell, J. F.; Kanekal, S. G.; Angelopoulos, V.; Green, J. C.; Goldstein, J.

    2016-06-01

    Various physical processes are known to cause acceleration, loss, and transport of energetic electrons in the Earth's radiation belts, but their quantitative roles in different time and space need further investigation. During the largest storm over the past decade (17 March 2015), relativistic electrons experienced fairly rapid acceleration up to ~7 MeV within 2 days after an initial substantial dropout, as observed by Van Allen Probes. In the present paper, we evaluate the relative roles of various physical processes during the recovery phase of this large storm using a 3-D diffusion simulation. By quantitatively comparing the observed and simulated electron evolution, we found that chorus plays a critical role in accelerating electrons up to several MeV near the developing peak location and produces characteristic flat-top pitch angle distributions. By only including radial diffusion, the simulation underestimates the observed electron acceleration, while radial diffusion plays an important role in redistributing electrons and potentially accelerates them to even higher energies. Moreover, plasmaspheric hiss is found to provide efficient pitch angle scattering losses for hundreds of keV electrons, while its scattering effect on > 1 MeV electrons is relatively slow. Although an additional loss process is required to fully explain the overestimated electron fluxes at multi-MeV, the combined physical processes of radial diffusion and pitch angle and energy diffusion by chorus and hiss reproduce the observed electron dynamics remarkably well, suggesting that quasi-linear diffusion theory is reasonable to evaluate radiation belt electron dynamics during this big storm.

  17. The problem of the acceleration of electrons of the outer radiation belt and magnetospheric substorms

    Science.gov (United States)

    Antonova, E. E.; Stepanova, M. V.

    2015-09-01

    Predicting of the location of the maximum in high-energy electron fluxes filling a new radiation belt is an endeavor being carried out by physicists studying the magnetosphere. We analyzed the data from the Defense Meteorological Satellite Program (DMSP) satellites and ground-based magnetometers obtained during geomagnetic storm on 8-9 October 2012. The minimum value of the disturbance storm time (Dst) was -111 nT, and the maximum in high-energy electron fluxes that appeared during the recovery phase was observed at L = 4 Re. At the same time, we analyzed the motion of the auroral oval toward lower latitudes and related substorm activity using the data of the low-orbiting DMSP satellites and the IMAGE magnetic meridian network. It was found from the DMSP satellites' measurements that the maximum of the energy density of precipitating ions, the maximum of the plasma pressure, and the most equatorial part of the westward auroral electrojet are all located at the 60° geomagnetic latitude. This value corresponds to L = 4 Re, i.e., it coincides with the location of the maximum in high-energy electron fluxes. This L-value also agrees with the predictions of the Tverskaya relation between the minimum in Dst variation and the location of the maximum of the energetic electron fluxes, filling a new radiation belt. The obtained results show that the location of this maximum could be predicted solely from the data of the auroral particle precipitations and/or ground-based magnetic observations.

  18. Modeling the Impenetrable Barrier to Inward Transport of Ultra-relativistic Radiation Belt Electrons

    Science.gov (United States)

    Tu, W.; Cunningham, G.; Chen, Y.; Baker, D. N.; Henderson, M. G.; Reeves, G. D.

    2014-12-01

    It has long been considered that the inner edge of the Earth's outer radiation belt is closely correlated with the minimum plasmapause location. However, recent discoveries by Baker et al. [1] show that it is not the case for ultra-relativistic electrons (2-10 MeV) in the radiation belt. Based on almost two years of Van Allen Probes/REPT data, they find that the inner edge of highly relativistic electrons is rarely collocated with the plasmapause; and more interestingly, there is a clear, persistent, and nearly impenetrable barrier to inward transport of high energy electrons, observed to locate at L~2.8. The presence of such an impenetrable barrier at this very specific location poses a significant puzzle. Using our DREAM3D diffusion model, which includes radial, pitch angle, and momentum diffusion, we are able to simulate the observed impenetrable barrier of ultra-relativistic electrons. The simulation demonstrates that during strong geomagnetic storms the plasmapause can be compressed to very low L region (sometimes as low as L~3), then strong chorus waves just outside the plasmapause can locally accelerate electrons up to multiple-MeV; when storm recovers, plasmapause moves back to large L, while the highly-relativistic electrons generated at low L continue to diffuse inward and slow decay by pitch angle diffusion from plasmaspheric hiss. The delicate balance between slow inward radial diffusion and weak pitch angle scattering creates a fixed inner boundary or barrier for ultra-relativistic electrons. The barrier is found to locate at a fixed L location, independent of the initial penetration depth of electrons that is correlated with the plasmapause location. Our simulation results quantitatively reproduce the evolution of the flux versus L profile, the L location of the barrier, and the decay rate of highly energetic electrons right outside the barrier. 1Baker, D. N., et al. (2014), Nearly Impenetrable Barrier to Inward Ultra-relativistic Magnetospheric

  19. ULF waves and relativistic electron acceleration and losses from the radiation belts: A superposed epoch analysis

    Science.gov (United States)

    Georgiou, Marina; Daglis, Ioannis; Zesta, Eftyhia; Katsavrias, Christos; Balasis, Georgios; Mann, Ian; Tsinganos, Kanaris

    2015-04-01

    Geospace magnetic storms are associated with either enhancements or decreases of the fluxes of electrons in the outer radiation belt. We examine the response of relativistic and ultra-relativistic electrons to 39 moderate and intense magnetic storms and compare these with concurrent observations of ULF wave power and of the plasmapause location. Following 27 of the magnetic storms, the ultra-relativistic electron population of the outer radiation belt was enhanced in the 2 - 6 MeV electron fluxes, as observed by SAMPEX. This enhancement was also seen in the electron phase space density derived from electron fluxes observed by the geosynchronous GOES satellites. On the other hand, the remaining 12 magnetic storms were not followed by enhancements in the relativistic electron population. We compare relativistic and ultra-relativistic electrons observations with the concurrent latitudinal and global distribution of wave power enhancements at Pc5 frequencies as detected by the CARISMA and IMAGE magnetometer arrays, as well as by magnetic stations collaborating in SuperMAG. During the main phase of both sets of magnetic storms, there is a marked penetration of Pc5 wave power to L shells as low as 2 -- especially during magnetic storms characterised by enhanced post-storm electron fluxes. Later in the recovery phase, Pc5 wave activity returns to more typical values and radial distribution with a peak at outer L shells. Pc5 wave activity was found to persist longer for the electron-enhanced storms than for those that do not produce such enhancements. We put our Pc5 wave observations in the context of the plasmapause location, as determined by IMAGE EUV observations. Specifically, we discuss the growth and decay characteristics of Pc5 waves in association with the plasmapause location, as a controlling factor for wave power penetration deep into the magnetosphere.

  20. Surface Daytime Net Radiation Estimation Using Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Bo Jiang

    2014-11-01

    Full Text Available Net all-wave surface radiation (Rn is one of the most important fundamental parameters in various applications. However, conventional Rn measurements are difficult to collect because of the high cost and ongoing maintenance of recording instruments. Therefore, various empirical Rn estimation models have been developed. This study presents the results of two artificial neural network (ANN models (general regression neural networks (GRNN and Neuroet to estimate Rn globally from multi-source data, including remotely sensed products, surface measurements, and meteorological reanalysis products. Rn estimates provided by the two ANNs were tested against in-situ radiation measurements obtained from 251 global sites between 1991–2010 both in global mode (all data were used to fit the models and in conditional mode (the data were divided into four subsets and the models were fitted separately. Based on the results obtained from extensive experiments, it has been proved that the two ANNs were superior to linear-based empirical models in both global and conditional modes and that the GRNN performed better and was more stable than Neuroet. The GRNN estimates had a determination coefficient (R2 of 0.92, a root mean square error (RMSE of 34.27 W∙m−2, and a bias of −0.61 W∙m−2 in global mode based on the validation dataset. This study concluded that ANN methods are a potentially powerful tool for global Rn estimation.

  1. Risk from exposure to natural and artificial ultraviolet radiation

    International Nuclear Information System (INIS)

    The association between exposure to ultraviolet (UV) and damage to the skin and eyes is today generally accepted. Exposure to UV radiation may occur in several ways. Apart from the sun, there is a wide range of artificial sources used in different fields of industry, research and medicine, the exposure to which adds to the total exposure of an individual during his life-span. The potential effects of ozone layer depletion on the increase of the solar UV radiation at earth's surface, and therefor on human health, have recently been emphasized. Moreover, great attention has been devoted to the often uncontrolled use of UV lamps for tanning. This report shows the basis on which short and long term UV risk is assessed, and indicates some parameters necessary to its evaluation. The UV effects, both at molecular and cellular levels and on humans, are described together with their respective action spectra. The most common UV sources are then analyzed and their use in different fields is shown. Finally, some methods in dosimetry, which are useful for the correct measurement of exposure values, are described

  2. Radial transport of radiation belt electrons due to stormtime Pc5 waves

    Directory of Open Access Journals (Sweden)

    A. Y. Ukhorskiy

    2009-05-01

    Full Text Available During geomagnetic storms relativistic electron fluxes in the outer radiation belt exhibit dynamic variability over multiple orders of magnitude. This requires radial transport of electrons across their drift shells and implies violation of their third adiabatic invariant. Radial transport is induced by the interaction of the electron drift motion with electric and magnetic field fluctuations in the ULF frequency range. It was previously shown that solar-wind driven ULF waves have long azimuthal wave lengths and thus can violate the third invariant of trapped electrons in the process of resonant interaction with their gradient-curvature motion. However, the amplitude of solar-wind driven ULF waves rapidly decreases with decreasing L. It is therefore not clear what mechanisms are responsible for fast transport rates observed inside the geosynchronous orbit. In this paper we investigate wether stormtime Pc5 waves can contribute to this process. Stormtime Pc5s have short azimuthal wave lengths and therefore cannot exhibit resonance with the the electron drift motion. However we show that stormtime Pc5s can cause localized random scattering of electron drift motion that violates the third invariant. According to our results electron interaction with stormtime Pc5s can produce rapid radial transport even as low as L≃4. Numerical simulations show that electron transport can exhibit large deviations from radial diffusion. The diffusion approximation is not valid for individual storms but only applies to the statistically averaged response of the outer belt to stormtime Pc5 waves.

  3. Prediction of radiation induced liver disease using artificial neural networks

    International Nuclear Information System (INIS)

    The objective of this study was to evaluate the efficiency of predicting radiation induced liver disease (RILD) with an artificial neural network (ANN) model. From August 2000 to November 2004, a total of 93 primary liver carcinoma (PLC) patients with single lesion and associated with hepatic cirrhosis of Child-Pugh grade A, were treated with hypofractionated three-dimensional conformal radiotherapy (3DCRT). Eight out of 93 patients were diagnosed RILD. Ninety-three patients were randomly divided into two subsets (training set and verification set). In model A, the ratio of patient numbers was 1:1 for training and verification set, and in model B, the ratio was 2:1. The areas under receiver-operating characteristic (ROC) curves were 0.8897 and 0.8831 for model A and B, respectively. Sensitivity, specificity, accuracy, positive prediction value (PPV) and negative prediction value (NPV) were 0.875 (7/8), 0.882 (75/85), 0.882 (82/93), 0.412 (7/17) and 0.987 (75/76) for model A, and 0.750 (6/8), 0.800 (68/85), 0.796 (74/93), 0.261 (6/23) and 0.971 (68/70) for model B. ANN was proved high accuracy for prediction of RILD. It could be used together with other models and dosimetric parameters to evaluate hepatic irradiation plans. (author)

  4. A Model for Hourly Solar Radiation Data Generation from Daily Solar Radiation Data Using a Generalized Regression Artificial Neural Network

    OpenAIRE

    Tamer Khatib; Wilfried Elmenreich

    2015-01-01

    This paper presents a model for predicting hourly solar radiation data using daily solar radiation averages. The proposed model is a generalized regression artificial neural network. This model has three inputs, namely, mean daily solar radiation, hour angle, and sunset hour angle. The output layer has one node which is mean hourly solar radiation. The training and development of the proposed model are done using MATLAB and 43800 records of hourly global solar radiation. The results show that...

  5. Influence of extremely low energy radiation on artificial tissue: Effects on image quality and superficial dose

    OpenAIRE

    Al-Akhras, M.-Ali H.; Aljarrah, K.; A Al-omari; H M Al-Khateeb; Albiss, B. A.; Azez, K.; Makhadmeh, G.

    2008-01-01

    The design and slicing technique of artificial soft tissue are presented. Artificial soft tissue has optical penetration properties similar to biological tissues. The soft tissues are made of agar dissolved in water as a transparent tissue (control) incorporated with scatter materials such as polystyrene microspheres and absorbers such as artificial dairy substitute, coffee mate (Carnation Co.). The radiation's interaction with 20 and 40 keV X-ray, and visible light (400–800 nm) with differen...

  6. ICME-driven sheath regions deplete the outer radiation belt electrons

    Science.gov (United States)

    Hietala, H.; Kilpua, E. K.; Turner, D. L.

    2013-12-01

    It is an outstanding question in space weather and solar wind-magnetosphere interaction studies, why some storms result in an increase of the outer radiation belt electron fluxes, while others deplete them or produce no change. One approach to this problem is to look at differences in the storm drivers. Traditionally drivers have been classified to Stream Interaction Regions (SIRs) and Interplanetary Coronal Mass Ejections (ICMEs). However, an 'ICME event' is a complex structure: The core is a magnetic cloud (MC; a clear flux rope structure). If the mass ejection is fast enough, it can drive a shock in front of it. This leads to the formation of a sheath region between the interplanetary shock and the leading edge of the MC. While both the sheath and the MC feature elevated solar wind speed, their other properties are very different. For instance, the sheath region has typically a much higher dynamic pressure than the magnetic cloud. Moreover, the sheath region has a high power in magnetic field and dynamic pressure Ultra Low Frequency (ULF) range fluctuations, while the MC is characterised by an extremely smooth magnetic field. Magnetic clouds have been recognised as important drivers magnetospheric activity since they can comprise long periods of very large southward Interplanetary Magnetic Field (IMF). Nevertheless, previous studies have shown that sheath regions can also act as storm drivers. In this study, we analyse the effects of ICME-driven sheath regions on the relativistic electron fluxes observed by GOES satellites on the geostationary orbit. We perform a superposed epoch analysis of 31 sheath regions from solar cycle 23. Our results show that the sheaths cause an approximately one order of magnitude decrease in the 24h-averaged electron fluxes. Typically the fluxes also stay below the pre-event level for more than two days. Further analysis reveals that the decrease does not depend on, e.g., whether the sheath interval contains predominantly northward

  7. On the possibility to use semiconductive hybrid pixel detectors for study of radiation belt of the Earth.

    Science.gov (United States)

    Guskov, A.; Shelkov, G.; Smolyanskiy, P.; Zhemchugov, A.

    2016-02-01

    The scientific apparatus GAMMA-400 designed for study of electromagnetic and hadron components of cosmic rays will be launched to an elliptic orbit with the apogee of about 300 000 km and the perigee of about 500 km. Such a configuration of the orbit allows it to cross periodically the radiation belt and the outer part of magnetosphere. We discuss the possibility to use hybrid pixel detecters based on the Timepix chip and semiconductive sensors on board the GAMMA-400 apparatus. Due to high granularity of the sensor (pixel size is 55 mum) and possibility to measure independently an energy deposition in each pixel, such compact and lightweight detector could be a unique instrument for study of spatial, energy and time structure of electron and proton components of the radiation belt.

  8. Identification of Non-Linear Space Weather Models of the Van Allen Radiation Belts Using Volterra Networks

    Science.gov (United States)

    Taylor, M.; Daglis, I. A.; Anastasiadis, A.; Vassiliadis, D.

    2010-07-01

    Many efforts have been made to develop general dynamical models of the Van Allen radiation belts based on data alone. Early linear prediction filter studies focused on the response of daily-averaged relativistic electrons at geostationary altitudes Nagai 1988, Baker et al. 1990). Vassiliadis et al (2005) extended this technique spatially by incorporating SAMPEX electron flux data into linear prediction filters for a broad range of L-shells from 1.1 to 10.0 RE. Nonlinear state space models (Rigler & Baker 2008) have provided useful initial results on the timescales involved in modeling the impulse-response of the radiation belts. Here, we show how NARMAX models, in conjunction with nonlinear time-delay FIR neural networks (Volterra networks) hold great promise for the development of accurate and fully data-derived space weather specification and forecast tools.

  9. On the possibility to use semiconductive hybrid pixel detectors for study of radiation belt of the Earth

    CERN Document Server

    Guskov, A; Smolyanskiy, P; Zhemchugov, A

    2015-01-01

    The scientific apparatus "Gamma-400" designed for study of hadron and electromagnetic components of cosmic rays will be launched to an elliptic orbit with the apogee of about 300 000 km and the perigee of about 500 km. Such a configuration of the orbit allows it to cross periodically the radiation belt and the outer part of magnetosphere. We discuss the possibility to use hybrid pixel detecters based on the Timepix chip and semiconductive sensors on board the "Gamma-400" apparatus. Due to high granularity of the sensor (pixel size is 55 $mu$m) and possibility to measure independently an energy deposition in each pixel, such compact and lightweight detector could be a unique instrument for study of spatial, energy and time structure of electron and proton components of the radiation belt.

  10. Remediation of radiation belt electrons caused by ground based man-made VLF wave%地基人工 VLF电波对辐射带电子的调制

    Institute of Scientific and Technical Information of China (English)

    王平; 徐岩冰; 于晓霞; 赵小芸; 吴峰; 王焕玉; 马宇蒨; 李新乔; 卢红; 孟祥承; 张吉龙; 王辉; 石峰

    2011-01-01

    辐射带电子的加速与沉降机理是空间物理研究的重要课题.法国DEMETER电磁卫星观测到了美国NPM发射站VLF信号及与之相关的高能电子沉降事例.本研究工作将根据基于回旋共振相互作用的准线性扩散理论,通过对局域投掷角扩散系数的计算,来说明受VLF影响的高能电子的投掷角分布与电子的能量及所处位置的关系.理论计算较好地解释了DEMETER卫星在NPM实验期间所观测到的电子沉降事例.在此基础上进一步讨论了通过人工方式对辐射带高能电子施加影响的效率问题.%The physics mechanisms of radiation belt electrons loss and acceleration are important issues in space physics research. Recently, France Microsatellite DEMETER has discovered the correlation between man- made VLF signals and radiation belt electrons precipitation in the NPM ( the U. S. VLF transmitter located at Lualualei ) experiment. Our research focuses on the explanation of the relation among affected pitch angle distribution, kinetic energy and position of electrons. This is achieved by calculating the local diffusion coeffcient based on the theory of qusi-linear diffusion with resonant interaction. Our result has a good explanation of radiation belt electron precipitation discovered by DEMETER during NPM experiment. Furthermore, we have discussed the effciency of radiation belt remediation in an artificial way.

  11. Ionization losses of the Earth's radiation belt protons according to the radial diffusion theory

    Science.gov (United States)

    Kovtyukh, A. S.

    2016-07-01

    Using modern models of the plasmasphere and exosphere, radial profiles of the rates of ionization losses of protons with μ = 0.3-10 keV/nT (μ is the first adiabatic invariant) of the Earth's radiation belts (ERBs) have been constructed. To calculate Coulomb losses of protons, we used the ISEE-1 satellite data at L = 3-9 and CRRES satellite data at L ≤ 3 ( L is the McIlwain parameter). The relation of contributions of Coulomb losses and charge exchange in the rate of ionization losses of protons has been considered. We have discovered the effect of subtracting Coulomb losses from charge exchange of ERB protons for small μ and L, which can imitate a local particle source. It has been demonstrated that, with decreasing L, the rate of ionization losses of ERB protons decreases as a whole. The radial dependence of this rate only has a negative gradient in the narrow range (Δ L ~ 0.5) in the region of the plasmapause and only for protons with μ > 1.2 keV/nT.

  12. The JCMT Gould Belt Survey: Evidence for radiative heating and contamination in the W40 complex

    CERN Document Server

    Rumble, D; Pattle, K; Kirk, H; Wilson, T; Buckle, J; Berry, D S; Broekhoven-Fiene, H; Currie, M J; Fich, M; Jenness, T; Johnstone, D; Mottram, J C; Nutter, D; Pineda, J E; Quinn, C; Salji, C; Tisi, S; Walker-Smith, S; Di Francesco, J; Hogerheijde, M R; Ward-Thompson, D; Bastien, P; Bresnahan, D; Butner, H; Chen, M; Chrysostomou, A; Coude, S; Davis, C J; Drabek-Maunder, E; Duarte-Cabral, A; Fiege, J; Friberg, P; Friesen, R; Fuller, G A; Graves, S; Greaves, J; Gregson, J; Holland, W; Joncas, G; Kirk, J M; Knee, L B G; Mairs, S; Matthews, B C; Moriarty-Schieven, G; Mowat, C; Rawlings, J; Richer, J; Robertson, D; Rosolowsky, E; Sadavoy, S; Thomas, H; Tothill, N; Viti, S; White, G J; Wouterloot, J; Yates, J; Zhu, M

    2016-01-01

    We present SCUBA-2 450{\\mu}m and 850{\\mu}m observations of the W40 complex in the Serpens-Aquila region as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) of nearby star-forming regions. We investigate radiative heating by constructing temperature maps from the ratio of SCUBA-2 fluxes using a fixed dust opacity spectral index, {\\beta} = 1.8, and a beam convolution kernel to achieve a common 14.8" resolution. We identify 82 clumps ranging between 10 and 36K with a mean temperature of 20{\\pm}3K. Clump temperature is strongly correlated with proximity to the external OB association and there is no evidence that the embedded protostars significantly heat the dust. We identify 31 clumps that have cores with densities greater than 105cm{^{-3}}. Thirteen of these cores contain embedded Class 0/I protostars. Many cores are associated with bright-rimmed clouds seen in Herschel 70 {\\mu}m images. From JCMT HARP observations of the 12CO 3-2 line, we find contamination of the 850{\\mu}m band of up ...

  13. Outer radiation belt dropout dynamics following the arrival of two interplanetary coronal mass ejections

    Science.gov (United States)

    Alves, L. R.; Da Silva, L. A.; Souza, V. M.; Sibeck, D. G.; Jauer, P. R.; Vieira, L. E. A.; Walsh, B. M.; Silveira, M. V. D.; Marchezi, J. P.; Rockenbach, M.; Lago, A. Dal; Mendes, O.; Tsurutani, B. T.; Koga, D.; Kanekal, S. G.; Baker, D. N.; Wygant, J. R.; Kletzing, C. A.

    2016-02-01

    Magnetopause shadowing and wave-particle interactions are recognized as the two primary mechanisms for losses of electrons from the outer radiation belt. We investigate these mechanisms, using satellite observations both in interplanetary space and within the magnetosphere and particle drift modeling. Two interplanetary shocks/sheaths impinged upon the magnetopause causing a relativistic electron flux dropout. The magnetic cloud (MC) and interplanetary structure sunward of the MC had primarily northward magnetic field, perhaps leading to a concomitant lack of substorm activity and a 10 daylong quiescent period. The arrival of two shocks caused an unusual electron flux dropout. Test-particle simulations have shown ˜ 2 to 5 MeV energy, equatorially mirroring electrons with initial values of L≥5.5 can be lost to the magnetosheath via magnetopause shadowing alone. For electron losses at lower L-shells, coherent chorus wave-driven pitch angle scattering and ULF wave-driven radial transport have been shown to be viable mechanisms.

  14. Effect of Chorus Latitudinal Distribution on Evolution of Outer Radiation Belt Electrons

    Institute of Scientific and Technical Information of China (English)

    XIAO Fuliang; LI Junqiu; TANG Lijun; HE Yihua; LI Jiangfan

    2009-01-01

    Primary result on the impact of the latitudinal distribution of whistler-mode chorus upon temporal evolution of the phase space density (PSD) of outer radiation belt energetic electrons was presented.We evaluate diffusion rates in pitch angle and momentum due to a band of chorus frequency distributed at a standard Gaussian spectrum,and solve a 2-D bounce-averaged momentum-pitch-angle Fokker-Planck equation at L=4.5.It is shown that chorus is effective in accelerating electrons and can increase PSD for energy of ~1 MeV by a factor of 10 or more in about one day,which is consistent with observation.Moreover,the latitudinal distribution of chorus has a great impact on the acceleration of electrons.As the latitudinal distribution increases,the efficient acceleration region extends from higher pitch angles to lower pitch angles,and even covers the entire pitch angle region when chorus power reaches the maximum latitude λm=45°.

  15. The outer boundary of radiation belts by the data of the ''Kosmos-426'' satellite

    International Nuclear Information System (INIS)

    Examined are the variations of the position of the external boundary of the radiation belts in magnetically calm periods as a function of the geomagnetic time MLT, orientation of the interplanetary magnetic field (IMF) and angle of slope of the geomagnetic dipole with respect to the Sun-Earth line. Experimental data have been obtained with the aid of the instrument which detected electrons with energies E > 20 keV on the ''Kosmos-426'' satellite during the period from 04.06.1971 to 3.01.1972. The effect of the angle of slope of the geomagnetic axis is maximum in after-midnight hours of MLT in the hemisphere with summer solstice. During the period of the northern orientation of the vertical component of IMF in almost all the MLT intervals, with the exception of after-midnight hours (2 to 8 hours MLT), the boundary is located at greater latitudes than in the southern orientation. The boundary correlates with the magnitude of the southern component of the IMF and does not correlate with the magnitude of the northern component of IMF

  16. Overview of Observations of Whistler-Mode Chorus by the Van Allen Probes in the Outer Radiation Belt

    Czech Academy of Sciences Publication Activity Database

    Santolík, Ondřej; Hospodarsky, G.; Kurth, W.; Averkamp, T. F.; Kletzing, C.

    Singapore: Asia Oceania Geosciences Society, 2015. ST15-19-A008. [AOGS Annual Meeting /12./ and APHW Conference /7./.. 02.08.2015–07.08.2015, Singapore] Institutional support: RVO:68378289 Keywords : whistler-mode chorus waves * Earth's Van Allen radiation belts Subject RIV: BL - Plasma and Gas Discharge Physics http://www.meetmatt-svr3.net/aogs/aogs2015/mars2/pubViewAbs.asp?sMode=session&sId=131&submit=Browse+Abstracts

  17. Dependence of radiation belt enhancements on the radial extent of Pc5 waves and the plasmapause location

    Science.gov (United States)

    Georgiou, M.; Daglis, I. A.; Zesta, E.; Balasis, G.; Katsavrias, C.; Mann, I. R.; Tsinganos, K.

    2014-12-01

    Low-energy electrons are accelerated to relativistic energies through different mechanisms, transporting them across their drift shells to the outer radiation belt. Among the different acceleration mechanisms, radial diffusion describes the result of ULF magnetic field pulsations resonantly interacting with radiation belt electrons. In this paper, the radial positioning of the relativistic electron population during 39 intense and moderate magnetic storms is examined against that of ULF Pc5 wave power and the plasmapause location. The relativistic electron population of the outer radiation belt appeared enhanced in the 2 - 6 MeV electron flux data from SAMPEX and in > 2 MeV electron flux data from the geosynchronous GOES satellites following 27 of the magnetic storms. We compared relativistic electrons observations with concurrent radial distribution of wave power enhancements at Pc5 frequencies as detected by the IMAGE and CARISMA magnetometer arrays, as well as by additional magnetic stations collaborating in SuperMAG. We discuss the growth and decay characteristics of Pc5 waves in association with the plasmapause location, determined from IMAGE EUV observations, as the controlling factor for wave power penetration deep into the magnetosphere. We show that, during magnetic storms characterized by increased post-storm fluxes, Pc5 wave power penetrates to L shells of 4 and lower. On the other hand, magnetic storms which were characterised by loss of electrons were related to low Pc5 wave activity, which was not intensified at low L shells. These observations provide support for the hypothesis that enhanced Pc5 wave activity deep into the magnetosphere during the main and recovery phase can discriminate between storms that result in increases of electron fluxes from those that do not. The work leading to this paper has received funding from the European Union's Seventh Framework Programme (FP7-SPACE-2011-1) under grant agreement no. 284520 for the MAARBLE

  18. Use of POES SEM-2 observations to examine radiation belt dynamics and energetic electron precipitation into the atmosphere

    OpenAIRE

    Rodger, Craig J.; Clilverd, Mark A.; Green, Janet C.; Lam, Mai Mai

    2010-01-01

    The coupling of the Van Allen radiation belts to the Earth's atmosphere through precipitating particles is an area of intense scientific interest. Currently, there are significant uncertainties surrounding the precipitating characteristics of medium energy electrons (> 20 keV), and even more uncertainties for relativistic electrons. In this paper we examine roughly 10 years of measurements of trapped and precipitating electrons available from the Polar Orbiting Environmental Satellites (POES)...

  19. The JCMT Gould Belt Survey: evidence for radiative heating and contamination in the W40 complex

    Science.gov (United States)

    Rumble, D.; Hatchell, J.; Pattle, K.; Kirk, H.; Wilson, T.; Buckle, J.; Berry, D. S.; Broekhoven-Fiene, H.; Currie, M. J.; Fich, M.; Jenness, T.; Johnstone, D.; Mottram, J. C.; Nutter, D.; Pineda, J. E.; Quinn, C.; Salji, C.; Tisi, S.; Walker-Smith, S.; Francesco, J. Di; Hogerheijde, M. R.; Ward-Thompson, D.; Bastien, P.; Bresnahan, D.; Butner, H.; Chen, M.; Chrysostomou, A.; Coude, S.; Davis, C. J.; Drabek-Maunder, E.; Duarte-Cabral, A.; Fiege, J.; Friberg, P.; Friesen, R.; Fuller, G. A.; Graves, S.; Greaves, J.; Gregson, J.; Holland, W.; Joncas, G.; Kirk, J. M.; Knee, L. B. G.; Mairs, S.; Marsh, K.; Matthews, B. C.; Moriarty-Schieven, G.; Mowat, C.; Rawlings, J.; Richer, J.; Robertson, D.; Rosolowsky, E.; Sadavoy, S.; Thomas, H.; Tothill, N.; Viti, S.; White, G. J.; Wouterloot, J.; Yates, J.; Zhu, M.

    2016-08-01

    We present SCUBA-2 450 μm and 850 μm observations of the W40 complex in the Serpens-Aquila region as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) of nearby star-forming regions. We investigate radiative heating by constructing temperature maps from the ratio of SCUBA-2 fluxes using a fixed dust opacity spectral index, β = 1.8, and a beam convolution kernel to achieve a common 14.8 arcsec resolution. We identify 82 clumps ranging between 10 and 36 K with a mean temperature of 20 ± 3 K. Clump temperature is strongly correlated with proximity to the external OB association and there is no evidence that the embedded protostars significantly heat the dust. We identify 31 clumps that have cores with densities greater than 105cm-3. 13 of these cores contain embedded Class 0/I protostars. Many cores are associated with bright-rimmed clouds seen in Herschel 70 μm images. From JCMT HARP observations of the 12CO 3-2 line, we find contamination of the 850 μm band of up to 20 per cent. We investigate the free-free contribution to SCUBA-2 bands from large-scale and ultracompact H II regions using archival VLA data and find the contribution is limited to individual stars, accounting for 9 per cent of flux per beam at 450 μm or 12 per cent at 850 μm in these cases. We conclude that radiative heating has potentially influenced the formation of stars in the Dust Arc sub-region, favouring Jeans stable clouds in the warm east and fragmentation in the cool west.

  20. Oblique Whistler-Mode Waves in the Earth's Inner Magnetosphere: Energy Distribution, Origins, and Role in Radiation Belt Dynamics

    Science.gov (United States)

    Artemyev, Anton; Agapitov, Oleksiy; Mourenas, Didier; Krasnoselskikh, Vladimir; Shastun, Vitalii; Mozer, Forrest

    2016-04-01

    In this paper we review recent spacecraft observations of oblique whistler-mode waves in the Earth's inner magnetosphere as well as the various consequences of the presence of such waves for electron scattering and acceleration. In particular, we survey the statistics of occurrences and intensity of oblique chorus waves in the region of the outer radiation belt, comprised between the plasmapause and geostationary orbit, and discuss how their actual distribution may be explained by a combination of linear and non-linear generation, propagation, and damping processes. We further examine how such oblique wave populations can be included into both quasi-linear diffusion models and fully nonlinear models of wave-particle interaction. On this basis, we demonstrate that varying amounts of oblique waves can significantly change the rates of particle scattering, acceleration, and precipitation into the atmosphere during quiet times as well as in the course of a storm. Finally, we discuss possible generation mechanisms for such oblique waves in the radiation belts. We demonstrate that oblique whistler-mode chorus waves can be considered as an important ingredient of the radiation belt system and can play a key role in many aspects of wave-particle resonant interactions.

  1. On the connection between large-amplitude whistlers, microbursts and nonlinear kinetic structures in the Earth's Radiation Belt

    Science.gov (United States)

    Osmane, A.; Wilson, L. B., III; Blum, L.; Pulkkinen, T. I.

    2015-12-01

    Using a dynamical-system approach we have investigated the efficiency of large-amplitude whistler waves for causing microburst precipitation in planetary radiation belts by modeling the microburst energy and particle fluxes produced as a result of non-linear wave-particle interactions. We show that wave parameters consistent with large-amplitude oblique whistlers commonly generate microbursts of electrons with hundreds of keV-energies, as a result of Landau trapping. Relativistic microbursts (> 1 MeV) can also be generated by a similar mechanism, but require waves with large propagation angles θ_{kB} > 50^{o} and phase-speeds v_{φ} > c/9. Using our result for precipitating density and energy fluxes, we argue that holes in the distribution function of electrons near the magnetic mirror point can result in the generation of electrostatic structures consistent in scales (of the order the Debye length) and electric field amplitudes (of the order of 1 mV/m) to nonlinear structures observed in the radiation belts by the Van Allen Probes. Our results indicate a relationship between nonlinear electrostatic and electromagnetic structures in the dynamics of planetary radiation belts and their role in the cyclical production of energetic electrons (i.e. E > 100 keV) on kinetic timescales, that is much faster than previously inferred.

  2. POES SEM-2 observations of radiation belt dynamics and energetic electron precipitation in to the atmosphere

    International Nuclear Information System (INIS)

    Complete text of publication follows. The coupling of the Van Allen radiation belts to the Earth's atmosphere through the effects of precipitating particles is an area of intense scientific interest. Currently, there are significant uncertainties surrounding the precipitating characteristics of medium energy electrons (>20 keV), and even more uncertainties for relativistic electrons. In this paper we examine roughly ten-years of measurements of trapped and precipitating electrons available from the Polar Orbiting Environmental Satellites (POES)/Space Environment Monitor (SEM-2) which has provided long-term global data in this energy range. Relativistic electron increases are associated with both interplanetary Coronal Mass Ejections (ICMEs) and periodic high speed solar wind streams (HSSWS). The processes triggered by ICMEs are roughly twice as effective at enhancing POES-observed electrons to relativistic energies as the processes triggered by HSSWS. We find that ICME-associated increases can extend down to L∼2, while other enhancements are generally limited to L>3.5. Finally, during HSSWS conditions there is an energy-dependent time delay observed in the POES/SEM-2 observations, with the >800 keV relativistic electron enhancement delayed by ∼1-week relative to the >30 keV electron enhancement, probably due to the timescales of the acceleration processes. One possible interpretation of this is a two-stage process, where relatively rapid acceleration initially takes place near the geomagnetic equator as predicted by theory and observed experimentally. This is followed by a much slower process, where the relativistic electrons scatter towards the atmosphere loss cone at a rate which is energy dependent. Such large delays should have consequences for the timing of the atmospheric impact of HSSWS-triggered geomagnetic storms.

  3. Command and Data Handling Flight Software test framework: A Radiation Belt Storm Probes practice

    Science.gov (United States)

    Hill, T. A.; Reid, W. M.; Wortman, K. A.

    During the Radiation Belt Storm Probes (RBSP) mission, a test framework was developed by the Embedded Applications Group in the Space Department at the Johns Hopkins Applied Physics Laboratory (APL). The test framework is implemented for verification of the Command and Data Handling (C& DH) Flight Software. The RBSP C& DH Flight Software consists of applications developed for use with Goddard Space Flight Center's core Flight Executive (cFE) architecture. The test framework's initial concept originated with tests developed for verification of the Autonomy rules that execute with the Autonomy Engine application of the RBSP C& DH Flight Software. The test framework was adopted and expanded for system and requirements verification of the RBSP C& DH Flight Software. During the evolution of the RBSP C& DH Flight Software test framework design, a set of script conventions and a script library were developed. The script conventions and library eased integration of system and requirements verification tests into a comprehensive automated test suite. The comprehensive test suite is currently being used to verify releases of the RBSP C& DH Flight Software. In addition to providing the details and benefits of the test framework, the discussion will include several lessons learned throughout the verification process of RBSP C& DH Flight Software. Our next mission, Solar Probe Plus (SPP), will use the cFE architecture for the C& DH Flight Software. SPP also plans to use the same ground system as RBSP. Many of the RBSP C& DH Flight Software applications are reusable on the SPP mission, therefore there is potential for test design and test framework reuse for system and requirements verification.

  4. Effects of Complex Interplanetary Structures on the Dynamics of the Earth's Outer Radiation Belt During the 16-30 September 2014 Period: II) Corotating Solar Wind Stream

    Science.gov (United States)

    Souza, V. M. C. E. S.; Da Silva, L. A.; Sibeck, D. G.; Alves, L. R.; Jauer, P. R.; Dias Silveira, M. V.; Medeiros, C.; Marchezi, J.; Rockenbach, M.; Baker, D. N.; Kletzing, C.; Kanekal, S. G.; Georgiou, M.; Mendes, O., Jr.; Dal Lago, A.; Vieira, L. E. A.

    2015-12-01

    We present a case study describing the dynamics of the outer radiation belt for two different solar wind conditions. First, we discuss a dropout of outer belt energetic electron fluxes corresponding to the arrival of an interplanetary coronal mass ejection (ICME) followed by a corotating stream in September 2014. Second, we discuss the reformation of the outer radiation belt that began on September 22nd. We find that the arrival of the ICME and the corotating interaction region that preceded the stream cause a long-duration (many day) dropout of high-energy electrons. The recovery in radiation belt fluxes only begins when the high-speed stream begins to develop IMF Bz fluctuations and auroral activity resumes. Furthermore, during periods in which several consecutive solar wind structures appear, the first structure primes the outer radiation belt prior to the interaction of the subsequent solar wind structures with the magnetosphere. Consequently, the evolution of the outer radiation belt through the solar cycle is significantly affected by the dominant structure of each phase of the cycle. We use energetic electron and magnetic field observations provided by the Van Allen Probes, THEMIS, and GOES missions.

  5. Plasmasphere dynamics during storms and its role in modulating the ring current and radiation belts: a review

    Science.gov (United States)

    Moldwin, Mark

    Global images of the plasmasphere from IMAGE EUV and global maps of the ionosphere using GPS TEC and tomography provide new global information of the dynamics of the plasmasphere in the aftermath of storms. Complex local time behavior including the development of plasma-spheric plumes and fine-scale density variations are often observed. Dynamics and structure observed in IMAGE EUV observations are closely mimicked in the topside ionosphere as ob-served with GPS TEC maps. GPS TEC tomography shows the connection between gradients in the topside ionosphere and the location of the equatorial plasmapause. Observations using IM-AGE FUV show a close correspondence between ion precipitation and the plasmaspheric plume and IMAGE EUV plasmapause observations and in situ radiation belt observations shows close correlation between the plasmapause and the inner edge of the outer belt. These observations indicate the clear and important role that plasmaspheric dynamics have on wave and particle populations in the inner magnetosphere.

  6. Evidence for dust-driven, radial plasma transport in Saturn's inner radiation belts

    Science.gov (United States)

    Roussos, E.; Krupp, N.; Kollmann, P.; Paranicas, C.; Mitchell, D. G.; Krimigis, S. M.; Andriopoulou, M.

    2016-08-01

    A survey of Cassini MIMI/LEMMS data acquired between 2004 and 2015 has led to the identification of 13 energetic electron microsignatures that can be attributed to particle losses on one of the several faint rings of the planet. Most of the signatures were detected near L-shells that map between the orbits of Mimas and Enceladus or near the G-ring. Our analysis indicates that it is very unlikely for these signatures to have originated from absorption on Mimas, Enceladus or unidentified Moons and rings, even though most were not found exactly at the L-shells of the known rings of the saturnian system (G-ring, Methone, Anthe, Pallene). The lack of additional absorbers is apparent in the L-shell distribution of MeV ions which are very sensitive for tracing the location of weakly absorbing material permanently present in Saturn's radiation belts. This sensitivity is demonstrated by the identification, for the first time, of the proton absorption signatures from the asteroid-sized Moons Pallene, Anthe and/or their rings. For this reason, we investigate the possibility that the 13 energetic electron events formed at known saturnian rings and the resulting depletions were later displaced radially by one or more magnetospheric processes. Our calculations indicate that the displacement magnitude for several of those signatures is much larger than the one that can be attributed to radial flows imposed by the recently discovered noon-to-midnight electric field in Saturn's inner magnetosphere. This observation is consistent with a mechanism where radial plasma velocities are enhanced near dusty obstacles. Several possibilities are discussed that may explain this observation, including a dust-driven magnetospheric interchange instability, mass loading by the pick-up of nanometer charged dust grains and global magnetospheric electric fields induced by perturbed orbits of charged dust due to the act of solar radiation pressure. Indirect evidence for a global scale interaction

  7. On the Relationship Between High Speed Solar Wind Streams and Radiation Belt Electron Fluxes

    Science.gov (United States)

    Zheng, Yihua

    2011-01-01

    Both past and recent research results indicate that solar wind speed has a close connection to radiation belt electron fluxes [e.g., Paulikas and Blake, 1979; Reeves et aI., 2011]: a higher solar wind speed is often associated with a higher level of radiation electron fluxes. But the relationship can be very complex [Reeves et aI., 2011]. The study presented here provides further corroboration of this viewpoint by emphasizing the importance of a global perspective and time history. We find that all the events during years 2010 and 2011 where the >0.8 MeV integral electron flux exceeds 10(exp 5) particles/sq cm/sr/s (pfu) at GEO orbit are associated with the high speed streams (HSS) following the onset of the Stream Interaction Region (SIR), with most of them belonging to the long-lasting Corotating Interaction Region (CIR). Our preliminary results indicate that during HSS events, a maximum speed of 700 km/s and above is a sufficient but not necessary condition for the > 0.8 MeV electron flux to reach 10(exp 5) pfu. But in the exception cases of HSS events where the electron flux level exceeds the 10(exp 5) pfu value but the maximum solar wind speed is less than 700 km/s, a prior impact can be noted either from a CME or a transient SIR within 3-4 days before the arrival of the HSS - stressing the importance of time history. Through superposed epoch analysis and studies providing comparisons with the CME events and the HSS events where the flux level fails to reach the 10(exp 5) pfu, we will present the quantitative assessment of behaviors and relationships of various quantities, such as the time it takes to reach the flux threshold value from the stream interface and its dependence on different physical parameters (e.g., duration of the HSS event, its maximum or average of the solar wind speed, IMF Bz, Kp). The ultimate goal is to apply what is derived to space weather forecasting.

  8. Prediction of Global Solar Radiation in India Using Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Rajiv Gupta

    2016-06-01

    Full Text Available Increasing global warming and decreasing fossil fuel reserves has necessitated the use of renewable energy resources like solar energy in India. To maximize return on a solar farm, it had to be set up at a place with high solar radiation. The solar radiation values are available only for a small number of places and must be interpolated for the rest. This paper utilizes Artificial Neural Network in interpolation, by obtaining a function with input as combinations of 7 geographical and meteorological parameters affecting radiation, and output as global solar radiation. Data considered was of past 9 years for 13 Indian cities. Low error values and high coefficient of determination values thus obtained, verified that the results were accurate in terms of the original solar radiation data known. Thus, artificial neural network can be used to interpolate the solar radiation for the places of interest depending on the availability of the data.

  9. BARREL observations of an ICME-shock impact with the magnetosphere and the resultant radiation belt electron loss

    Science.gov (United States)

    Halford, A. J.; McGregor, S. L.; Murphy, K. R.; Millan, R. M.; Hudson, M. K.; Woodger, L. A.; Cattel, C. A.; Breneman, A. W.; Mann, I. R.; Kurth, W. S.; Hospodarsky, G. B.; Gkioulidou, M.; Fennell, J. F.

    2015-04-01

    The Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) mission of opportunity working in tandem with the Van Allen Probes was designed to study the loss of radiation belt electrons to the ionosphere and upper atmosphere. BARREL is also sensitive to X-rays from other sources. During the second BARREL campaign, the Sun produced an X-class flare followed by a solar energetic particle event (SEP) associated with the same active region. Two days later on 9 January 2014, the shock generated by the coronal mass ejection (CME) originating from the active region hits the Earth while BARREL was in a close conjunction with the Van Allen Probes. Time History Events and Macroscale Interactions during Substorms (THEMIS) satellite observed the impact of the interplanetary CME (ICME) shock near the magnetopause, and the Geostationary Operational Environmental Satellites (GOES) were on either side of the BARREL/Van Allen Probe array. The solar interplanetary magnetic field was not ideally oriented to cause a significant geomagnetic storm, but compression from the shock impact led to the loss of radiation belt electrons. We propose that an azimuthal electric field impulse generated by magnetopause compression caused inward electron transport and minimal loss. This process also drove chorus waves, which were responsible for most of the precipitation observed outside the plasmapause. Observations of hiss inside the plasmapause explain the absence of loss at this location. ULF waves were found to be correlated with the structure of the precipitation. We demonstrate how BARREL can monitor precipitation following an ICME-shock impact at Earth in a cradle-to-grave view; from flare, to SEP, to electron precipitation.

  10. Forecasting the Earth’s radiation belts and modelling solar energetic particle events: Recent results from SPACECAST

    Directory of Open Access Journals (Sweden)

    Poedts Stefaan

    2013-05-01

    Full Text Available High-energy charged particles in the van Allen radiation belts and in solar energetic particle events can damage satellites on orbit leading to malfunctions and loss of satellite service. Here we describe some recent results from the SPACECAST project on modelling and forecasting the radiation belts, and modelling solar energetic particle events. We describe the SPACECAST forecasting system that uses physical models that include wave-particle interactions to forecast the electron radiation belts up to 3 h ahead. We show that the forecasts were able to reproduce the >2 MeV electron flux at GOES 13 during the moderate storm of 7–8 October 2012, and the period following a fast solar wind stream on 25–26 October 2012 to within a factor of 5 or so. At lower energies of 10 – a few 100 keV we show that the electron flux at geostationary orbit depends sensitively on the high-energy tail of the source distribution near 10 RE on the nightside of the Earth, and that the source is best represented by a kappa distribution. We present a new model of whistler mode chorus determined from multiple satellite measurements which shows that the effects of wave-particle interactions beyond geostationary orbit are likely to be very significant. We also present radial diffusion coefficients calculated from satellite data at geostationary orbit which vary with Kp by over four orders of magnitude. We describe a new automated method to determine the position at the shock that is magnetically connected to the Earth for modelling solar energetic particle events and which takes into account entropy, and predict the form of the mean free path in the foreshock, and particle injection efficiency at the shock from analytical theory which can be tested in simulations.

  11. Statistics of whistler mode waves in the outer radiation belt: Cluster STAFF-SA measurements

    International Nuclear Information System (INIS)

    ELF/VLF waves play a crucial role in the dynamics of the radiation belts and are partly responsible for the main losses and the acceleration of energetic electrons. Modeling wave-particle interactions requires detailed information of wave amplitudes and wave normal distribution over L-shells and over magnetic latitudes for different geomagnetic activity conditions. We performed a statistical study of ELF/VLF emissions using wave measurements in the whistler frequency range for 10 years (2001-2010) aboard Cluster spacecraft. We utilized data from the STAFF-SA experiment, which spans the frequency range from 8 Hz to 4 kHz. We present distributions of wave magnetic and electric field amplitudes and wave normal directions as functions of magnetic latitude, magnetic local time, L-shell, and geomagnetic activity. We show that wave normals are directed approximately along the background magnetic field (with the mean value of θ the angle between the wave normal and the background magnetic field, about 10-15 degrees) in the vicinity of the geomagnetic equator. The distribution changes with magnetic latitude: Plasma spheric hiss normal angles increase with latitude to quasi-perpendicular direction at 35-40 degrees where hiss can be reflected; lower band chorus are observed as two wave populations: One population of wave normals tends toward the resonance cone and at latitudes of around 35-45 degrees wave normals become nearly perpendicular to the magnetic field; the other part remains quasi-parallel at latitudes up to 30 degrees. The observed angular distribution is significantly different from Gaussian, and the width of the distribution increases with latitude. Due to the rapid increase of θ the wave mode becomes quasi-electrostatic, and the corresponding electric field increases with latitude and has a maximum near 30 degrees. The magnetic field amplitude of the chorus in the day sector has a minimum at the magnetic equator but increases rapidly with latitude with a

  12. Beam-excited whistler waves at oblique propagation with relation to STEREO radiation belt observations

    Directory of Open Access Journals (Sweden)

    K. Sauer

    2010-06-01

    Full Text Available Isotropic electron beams are considered to explain the excitation of whistler waves which have been observed by the STEREO satellite in the Earth's radiation belt. Aside from their large amplitudes (~240 mV/m, another main signature is the strongly inclined propagation direction relative to the ambient magnetic field. Electron temperature anisotropy with Te⊥>Te||, which preferentially generates parallel propagating whistler waves, can be excluded as a free energy source. The instability arises due to the interaction of the Doppler-shifted cyclotron mode ω=−Ωe+kVbcosθ with the whistler mode in the wave number range of kce≤1 (θ is the propagation angle with respect to the background magnetic field direction, ωe is the electron plasma frequency and Ωe the electron cyclotron frequency. Fluid and kinetic dispersion analysis have been used to calculate the growth rate of the beam-excited whistlers including the most important parameter dependencies. One is the beam velocity (Vb which, for instability, has to be larger than about 2VAe, where VAe is the electron Alfvén speed. With increasing VAe the propagation angle (θ of the fastest growing whistler waves shifts from θ~20° for Vb=2VAe to θ~80° for Vb=5VAe. The growth rate is reduced by finite electron temperatures and disappears if the electron plasma beta (βe exceeds βe~0.2. In addition, Gendrin modes (kce≈1 are analyzed to determine the conditions under which stationary nonlinear waves (whistler oscillitons can exist. The corresponding spatial wave profiles are calculated using the full nonlinear fluid approach. The results are compared with the STEREO satellite observations.

  13. Layered Model for Radiation-Induced Chemical Evolution of Icy Surface Composition on Kuiper Belt and Oort Cloud Bodies

    Science.gov (United States)

    Cooper, John F.; Hill, Matthew E.; Richardson, John D.; Sturner, Steven J.

    2010-01-01

    The diversity of albedos and surface colors on observed Kuiper Belt and Inner Oort Cloud objects remains to be explained in terms of competition between primordial intrinsic versus exogenic drivers of surface and near-surface evolution. Earlier models have attempted without success to attribute this diversity to the relations between surface radiolysis from cosmic ray irradiation and gardening by meteoritic impacts. A more flexible approach considers the different depth-dependent radiation profiles produced by low-energy plasma, suprathermal, and maximally penetrating charged particles of the heliospheric and local interstellar radiation environments. Generally red objects of the dynamically cold (low inclination, circular orbit) Classical Kuiper Belt might be accounted for from erosive effects of plasma ions and reddening effects of high energy cosmic ray ions, while suprathermal keV-MeV ions could alternatively produce more color neutral surfaces. The deepest layer of more pristine ice can be brought to the surface from meter to kilometer depths by larger impact events and potentially by cryovolcanic activity. The bright surfaces of some larger objects, e.g. Eris, suggest ongoing resurfacing activity. Interactions of surface irradiation, resultant chemical oxidation, and near-surface cryogenic fluid reservoirs have been proposed to account for Enceladus cryovolcanism and may have further applications to other icy irradiated bodies. The diversity of causative processes must be understood to account for observationally apparent diversities of the object surfaces.

  14. Simulation of Resonant Interaction between Energetic Electrons and Whistler-Mode Chorus in the Outer Radiation Belt

    Institute of Scientific and Technical Information of China (English)

    SU Zhen-Peng; ZHENG Hui-Nan

    2008-01-01

    @@ We construct a realistic model to evaluate the chorus wave--particle interaction in the outer radiation belt L = 4.5.This model incorporates a plasmatrough number density model, a field-aligned density model and a realistic wave power and frequency model.We solve the 2D bounce-averaged momentum-pitch-angle Fokker-Planck equation and show that the Whistler-mode chorus can be effective in the acceleration of electrons, and enhance the phase space density for energies of ~1 Me V by a factor from 10 to 103 in about two days, consistent with the observation.We also demonstrate that ignorance of the electron number density variation along field line and magnetic local time in the previous work yields an overestimate of energetic electron phase space density by a factor 5~10 at large pitch-angle after two days, suggesting that a realistic plasma density model is very important to evaluate the evolution of energetic electrons in the outer radiation belt.

  15. Cancer risk at low doses of ionizing radiation: artificial neural networks inference from atomic bomb survivors

    OpenAIRE

    Sasaki, Masao S.; Tachibana, Akira; Takeda, Shunichi

    2013-01-01

    Cancer risk at low doses of ionizing radiation remains poorly defined because of ambiguity in the quantitative link to doses below 0.2 Sv in atomic bomb survivors in Hiroshima and Nagasaki arising from limitations in the statistical power and information available on overall radiation dose. To deal with these difficulties, a novel nonparametric statistics based on the ‘integrate-and-fire’ algorithm of artificial neural networks was developed and tested in cancer databases established by the R...

  16. Cancer risk at low doses of ionizing radiation: artificial neural networks inference from atomic bomb survivors.

    OpenAIRE

    Sasaki, Masao S.; Tachibana, Akira; Takeda, Shunichi

    2014-01-01

    Cancer risk at low doses of ionizing radiation remains poorly defined because of ambiguity in the quantitative link to doses below 0.2 Sv in atomic bomb survivors in Hiroshima and Nagasaki arising from limitations in the statistical power and information available on overall radiation dose. To deal with these difficulties, a novel nonparametric statistics based on the 'integrate-and-fire' algorithm of artificial neural networks was developed and tested in cancer databases established by the R...

  17. Prediction of Global Solar Radiation in India using Artificial Neural Network

    OpenAIRE

    Rajiv Gupta; Saurabh Singhal

    2016-01-01

    Increasing global warming and decreasing fossil fuel reserves has necessitated the use of renewable energy resources like solar energy in India. To maximize return on a solar farm, it had to be set up at a place with high solar radiation. The solar radiation values are available only for a small number of places and must be interpolated for the rest. This paper utilizes Artificial Neural Network in interpolation, by obtaining a function with input as combinations of 7 geographical and meteoro...

  18. Radiation of lamp and optimized experiment using artificial light in the Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jin-ping; David Barber; LI Tao; LI Shu-jiang; LI Xiang

    2008-01-01

    A winter optical experiment by an artificial lamp was conducted in the Amundsen Bay of Arctic Ocean from November of 2007 to January of 2008. The radiation field emitted from an artificial lamp was measured and is introduced in this paper, and the optimized experiment project is discussed. It is demonstrated that the minimum size allowed of the lamp is determined by both the field of view (FOV) of optical instrument and the measuring distance from the lamp. Some problems that might influence on the experiment result often occur for a simple fluorescent lamp,such as instability, spatial nonuniformity, light divergence, effect of lamp temperature, etc. By the analysis of the light radiation, three kind of measures are proposed to control the quality of the experiment, i.e. keeping consistency of lamp size with FOV of instrument, calibrating in situ downwind, and conducting measurement in effective range. Among them, the downwind calibration is the key step to overcome most problems arose by the lamp. The experiment indicated that the reliable results can be obtained only when the optical measurement is coordinated with the radiation field of artificial lamp. The measured radiation property of the lamp was used to advise the field experiment to minimize measuring error. As the experiment by artificial lamp was the first attempt in the Arctic Ocean, the experience given by this paper is a valuable reference to the correlative studies.

  19. Van Allen Probes Mission Space Academy: Educating middle school students about Earth's mysterious radiation belts

    Science.gov (United States)

    Butler, L.; Turney, D.; Matiella Novak, A.; Smith, D.; Simon, M.

    2013-12-01

    How's the weather in space? Why on Earth did NASA send two satellites above Earth to study radiation belts and space weather? To learn the answer to questions about NASA's Van Allen Probes mission, 450 students and their teachers from Maryland middle schools attended Space Academy events highlighting the Van Allen Probes mission. Sponsored by the Applied Physics Laboratory (APL) and Discovery Education, the events are held at the APL campus in Laurel, MD. Space Academies take students and teachers on behind-the-scenes exploration of how spacecraft are built, what they are designed to study, and introduces them to the many professionals that work together to create some of NASA's most exciting projects. Moderated by a public relations representative in the format of an official NASA press conference, the daylong event includes a student press conference with students as reporters and mission experts as panelists. Lunch with mission team members gives students a chance to ask more questions. After lunch, students don souvenir clean room suits, enjoy interactive science demonstrations, and tour APL facilities where the Van Allen Probes were built and tested before launch. Students may even have an opportunity to peek inside a clean room to view spacecraft being assembled. Prior to the event, teachers are provided with classroom activities, lesson plans, and videos developed by APL and Discovery Education to help prepare students for the featured mission. The activities are aligned to National Science Education Standards and appropriate for use in the classroom. Following their visit, student journalists are encouraged to write a short article about their field trip; selections are posted on the Space Academy web site. Designed to engage, inspire, and influence attitudes about space science and STEM careers, Space Academies provide an opportunity to attract underserved populations and emphasize that space science is for everyone. Exposing students to a diverse group of

  20. Stormtime ring current and radiation belt ion transport: Simulations and interpretations

    Science.gov (United States)

    Lyons, Larry R.; Gorney, David J.; Chen, Margaret W.; Schulz, Michael

    1995-01-01

    We use a dynamical guiding-center model to investigate the stormtime transport of ring current and radiation-belt ions. We trace the motion of representative ions' guiding centers in response to model substorm-associated impulses in the convection electric field for a range of ion energies. Our simple magnetospheric model allows us to compare our numerical results quantitatively with analytical descriptions of particle transport, (e.g., with the quasilinear theory of radial diffusion). We find that 10-145-keV ions gain access to L approximately 3, where they can form the stormtime ring current, mainly from outside the (trapping) region in which particles execute closed drift paths. Conversely, the transport of higher-energy ions (approximately greater than 145 keV at L approximately 3) turns out to resemble radial diffusion. The quasilinear diffusion coefficient calculated for our model storm does not vary smoothly with particle energy, since our impulses occur at specific (although randomly determined) times. Despite the spectral irregularity, quasilinear theory provides a surprisingly accurate description of the transport process for approximately greater than 145-keV ions, even for the case of an individual storm. For 4 different realizations of our model storm, the geometric mean discrepancies between diffusion coefficients D(sup sim, sub LL) obtained from the simulations and the quasilinear diffusion coefficient D(sup ql, sub LL) amount to factors of 2.3, 2.3, 1.5, and 3.0, respectively. We have found that these discrepancies between D(sup sim, sub LL) and D(sup ql, sub LL) can be reduced slightly by invoking drift-resonance broadening to smooth out the sharp minima and maxima in D(sup ql, sub LL). The mean of the remaining discrepancies between D(sup sim, sub LL) and D(sup ql, sub LL) for the 4 different storms then amount to factors of 1.9, 2.1, 1.5, and 2.7, respectively. We find even better agreement when we reduce the impulse amplitudes systematically in

  1. Electron loss rates from the outer radiation belt caused by the filling of the outer plasmasphere: the calm before the storm

    Energy Technology Data Exchange (ETDEWEB)

    Borovsky, Joseph E [Los Alamos National Laboratory; Denton, Michael H [LANCASTER UNIV

    2009-01-01

    Measurements from 7 spacecraft in geosynchronous orbit are analyzed to determine the decay rate of the number density of the outer electron radiation belt prior to the onset of high-speed-stream-driven geomagnetic storms. Superposed-data analysis is used wan(?) a collection of 124 storms. When there is a calm before the storm, the electron number density decays exponentially before the storm with a 3.4-day e-folding time: beginning about 4 days before storm onset, the density decreases from {approx}4x10{sup -4} cm{sup -3} to {approx}1X 10{sup -4} cm{sup -3}. When there is not a calm before the storm, the number-density decay is very smalL The decay in the number density of radiation-belt electrons is believed to be caused by pitch-angle scattering of electrons into the atmospheric loss cone as the outer plasmasphere fills during the calms. While the radiation-belt electron density decreases, the temperature of the electron radiation belt holds approximately constant, indicating that the electron precipitation occurs equally at all energies. Along with the number density decay, the pressure of the outer electron radiation belt decays and the specific entropy increases. From the measured decay rates, the electron flux to the atmosphere is calculated and that flux is 3 orders of magnitude less than thermal fluxes in the magnetosphere, indicating that the radiation-belt pitch-angle scattering is 3 orders weaker than strong diffusion. Energy fluxes into the atmosphere are calculated and found to be insufficient to produce visible airglow.

  2. A Nano-satellite Mission to Study Charged Particle Precipitation from the Van Allen Radiation Belts caused due to Seismo-Electromagnetic Emissions

    CERN Document Server

    Sivadas, Nithin; Kannapan, Deepti; Yalamarthy, Ananth Saran; Dhiman, Ankit; Bhagoji, Arjun; Shankar, Athreya; Prasad, Nitin; Ramachandran, Harishankar; Koilpillai, R David

    2014-01-01

    In the past decade, several attempts have been made to study the effects of seismo-electromagnetic emissions - an earthquake precursor, on the ionosphere and the radiation belts. The IIT Madras nano-satellite (IITMSAT) mission is designed to make sensitive measurements of charged particle fluxes in a Low Earth Orbit to study the nature of charged particle precipitation from the Van Allen radiation belts caused due to such emissions. With the Space-based Proton Electron Energy Detector on-board a single nano-satellite, the mission will attempt to gather statistically significant data to verify possible correlations with seismo-electromagnetic emissions before major earthquakes.

  3. Short-term changes in Jupiter's synchrotron radiation at 325 MHz: Enhanced radial diffusion in Jupiter's radiation belt driven by solar UV/EUV heating

    Science.gov (United States)

    Tsuchiya, F.; Misawa, H.; Imai, K.; Morioka, A.

    2011-09-01

    The total flux density of Jupiter's synchrotron radiation (JSR) at 325 MHz was observed in 2007 with the Iitate Planetary Radio Telescope to investigate short-term variations in Jupiter's radiation belt with a time scale of a few days to a month. The total flux density showed a series of short-term increases and subsequent decreases. The variations in JSR and the Mg II solar UV/EUV index showed positive correlations, but the variations in JSR were preceded by those of the Mg II index by 3-5 days. The positive correlation supports a theoretical prediction that an enhancement in the radial diffusion driven by thermospheric winds in the upper atmosphere causes changes in relativistic electron distributions in both the radiation belt and the total flux density of JSR. The radial diffusion model was used to examine the hypothesis that temporal changes in the radial diffusion rate could be an origin of the short-term variation. The model includes physical processes such as radial diffusion, energy degradation by the synchrotron radiation, and several loss processes. We applied a radial diffusion coefficient of 3 × 10-8 L3/s and found a suitable solution that accounted for both the time scale of the short-term variations and the 4 day time lag. The model also showed that strong electron loss processes other than the synchrotron radiation are needed to explain the electron distribution in low L regions. An empirical electron distribution model showed that the synchrotron radiation does not act as a loss of electrons in such areas.

  4. Long-term solar UV radiation reconstructed by Artificial Neural Networks (ANN

    Directory of Open Access Journals (Sweden)

    U. Feister

    2008-01-01

    Full Text Available Artificial Neural Networks (ANN are efficient tools to derive solar UV radiation from measured meteorological parameters such as global radiation, aerosol optical depths and atmospheric column ozone. The ANN model has been tested with different combinations of data from the two sites Potsdam and Lindenberg, and used to reconstruct solar UV radiation at eight European sites by more than 100 years into the past. Annual totals of UV radiation derived from reconstructed daily UV values reflect interannual variations and long-term patterns that are compatible with variabilities and changes of measured input data, in particular global dimming by about 1980–1990, subsequent global brightening, volcanic eruption effects such as that of Mt. Pinatubo, and the long-term ozone decline since the 1970s. Patterns of annual erythemal UV radiation are very similar at sites located at latitudes close to each other, but different patterns occur between UV radiation at sites in different latitude regions.

  5. Relation between the short-term variation of the Jovian radiation belt and thermosphere derived from radio and infrared observations

    Science.gov (United States)

    Kita, Hajime; Misawa, Hiroaki; Bhardwaj, Anil; Tsuchiya, Fuminori; Sakanoi, Takeshi; Kasaba, Yasumasa; Tao, Chihiro; Miyoshi, Yoshizumi; Morioka, Akira

    2015-08-01

    We report the first comprehensive observations of Jovian synchrotron radiation (JSR) and H3+ emission from the Jovian thermosphere to investigate the generation process of short-term (days to weeks) variations in the Jovian radiation belt. The observations were made by the Giant Metrewave Radio Telescope and NASA Infrared Telescope Facility during November 2011. The total flux density of JSR increased by approximately 5% between 6-9 November and 12-17 November, associated with the increased solar UV/EUV flux. From 7 to 14 November, a possible rise in the infrared H3+ emission was observed in the middle-latitude region, corresponding to a temperature variation of approximately 10 K. These results are consistent with the scenario that the solar UV/EUV heating causes variations in the thermospheric temperature and JSR. Radio images along the equatorial region showed that the JSR intensity decreased inside 1.5 Jovian radii (RJ) and the peak position shifted outward. This implies that energetic electrons are attenuated by some internal loss process, despite the simultaneous increase in radial diffusion. A physical model for the radiation belt shows that such an internal loss process can explain the observed variation of brightness distribution. Typical loss time scale is longer than strong diffusion limit, which suggests the existence of some pitch angle diffusion process such as wave-particle interaction. Thus, variations of the total JSR flux density and thermospheric temperature seem consistent with the scenario, and the brightness distribution of JSR can be explained by the increase in radial diffusion accompanied by internal loss processes.

  6. Lightning-driven inner radiation belt energy deposition into the atmosphere: implications for ionisation-levels and neutral chemistry

    Directory of Open Access Journals (Sweden)

    C. J. Rodger

    2007-08-01

    Full Text Available Lightning-generated whistlers lead to coupling between the troposphere, the Van Allen radiation belts and the lower-ionosphere through Whistler-induced electron precipitation (WEP. Lightning produced whistlers interact with cyclotron resonant radiation belt electrons, leading to pitch-angle scattering into the bounce loss cone and precipitation into the atmosphere. Here we consider the relative significance of WEP to the lower ionosphere and atmosphere by contrasting WEP produced ionisation rate changes with those from Galactic Cosmic Radiation (GCR and solar photoionisation. During the day, WEP is never a significant source of ionisation in the lower ionosphere for any location or altitude. At nighttime, GCR is more significant than WEP at altitudes <68 km for all locations, above which WEP starts to dominate in North America and Central Europe. Between 75 and 80 km altitude WEP becomes more significant than GCR for the majority of spatial locations at which WEP deposits energy. The size of the regions in which WEP is the most important nighttime ionisation source peaks at ~80 km, depending on the relative contributions of WEP and nighttime solar Lyman-α. We also used the Sodankylä Ion Chemistry (SIC model to consider the atmospheric consequences of WEP, focusing on a case-study period. Previous studies have also shown that energetic particle precipitation can lead to large-scale changes in the chemical makeup of the neutral atmosphere by enhancing minor chemical species that play a key role in the ozone balance of the middle atmosphere. However, SIC modelling indicates that the neutral atmospheric changes driven by WEP are insignificant due to the short timescale of the WEP bursts. Overall we find that WEP is a significant energy input into some parts of the lower ionosphere, depending on the latitude/longitude and altitude, but does not play a significant role in the neutral chemistry of the mesosphere.

  7. Effect of gamma radiation on some artificial blood substitutes

    International Nuclear Information System (INIS)

    Effects of gamma irradiation of dextran 40,000 and 70,000 with doses of 0.5-4.5 Mrad were investigated. The powdered dextran samples were irradiated in glass vessels. The samples were dried before or after the exposure to radiation. There were determined changes in pH, reducing, buffer capacity, colouration, viscosity of the whole preparations, and viscosity of particular fractions separated by column chromatography. Thin-layer chromatography was used to check the irradiated samples for presence of simple sugars. Radioresistance of dextran preparations proved to be enhanced by drying before the exposure. (author)

  8. Combined scattering loss of radiation belt relativistic electrons by simultaneous three-band EMIC waves: A case study

    Science.gov (United States)

    He, Fengming; Cao, Xing; Ni, Binbin; Xiang, Zheng; Zhou, Chen; Gu, Xudong; Zhao, Zhengyu; Shi, Run; Wang, Qi

    2016-05-01

    Multiband electromagnetic ion cyclotron (EMIC) waves can drive efficient scattering loss of radiation belt relativistic electrons. However, it is statistically uncommon to capture the three bands of EMIC waves concurrently. Utilizing data from the Electric and Magnetic Field Instrument Suite and Integrated Science magnetometer onboard Van Allen Probe A, we report the simultaneous presence of three (H+, He+, and O+) emission bands in an EMIC wave event, which provides an opportunity to look into the combined scattering effect of all EMIC emissions and the relative roles of each band in diffusing radiation belt relativistic electrons under realistic circumstances. Our quantitative results, obtained by quasi-linear diffusion rate computations and 1-D pure pitch angle diffusion simulations, demonstrate that the combined resonant scattering by the simultaneous three-band EMIC waves is overall dominated by He+ band wave diffusion, mainly due to its dominance over the wave power (the mean wave amplitudes are approximately 0.4 nT, 1.6 nT, and 0.15 nT for H+, He+, and O+ bands, respectively). Near the loss cone, while 2-3 MeV electrons undergo pitch angle scattering at a rate of the order of 10-6-10-5 s-1, 5-10 MeV electrons can be diffused more efficiently at a rate of the order of 10-3-10-2 s-1, which approaches the strong diffusion level and results in a moderately or heavily filled loss cone for the atmospheric loss. The corresponding electron loss timescales (i.e., lifetimes) vary from several days at the energies of ~2 MeV to less than 1 h at ~10 MeV. This case study indicates the leading contribution of He+ band waves to radiation belt relativistic electron losses during the coexistence of three EMIC wave bands and suggests that the roles of different EMIC wave bands in the relativistic electron dynamics should be carefully incorporated in future modeling efforts.

  9. LANL* V1.0: a radiation belt drift shell model suitable for real-time and reanalysis applications

    Directory of Open Access Journals (Sweden)

    J. Koller

    2009-07-01

    Full Text Available We describe here a new method for calculating the magnetic drift invariant, L*, that is used for modeling radiation belt dynamics and for other space weather applications. L* (pronounced L-star is directly proportional to the integral of the magnetic flux contained within the surface defined by a charged particle moving in the Earth's geomagnetic field. Under adiabatic changes to the geomagnetic field L* is a conserved quantity, while under quasi-adiabatic fluctuations diffusion (with respect to a particle's L* is the primary term in equations of particle dynamics. In particular the equations of motion for the very energetic particles that populate the Earth's radiation belts are most commonly expressed by diffusion in three dimensions: L*, energy (or momentum, and pitch angle (the dot product of velocity and the magnetic field vector. Expressing dynamics in these coordinates reduces the dimensionality of the problem by referencing the particle distribution functions to values at the magnetic equatorial point of a magnetic "drift shell" (or L-shell irrespective of local time (or longitude. While the use of L* aids in simplifying the equations of motion, practical applications such as space weather forecasting using realistic geomagnetic fields require sophisticated magnetic field models that, in turn, require computationally intensive numerical integration. Typically a single L* calculation can require on the order of 105 calls to a magnetic field model and each point in the simulation domain and each calculated pitch angle has a different value of L*. We describe here the development and validation of a neural network surrogate model for calculating L* in sophisticated geomagnetic field models with a high degree of fidelity at computational speeds that are millions of times faster than direct numerical field line mapping and integration. This new surrogate model has

  10. The JCMT Gould Belt Survey: Evidence for radiative heating in Serpens MWC 297 and its influence on local star formation

    CERN Document Server

    Rumble, D; Gutermuth, R A; Kirk, H; Buckle, J; Beaulieu, S F; Berry, D S; Broekhoven-Fiene, H; Currie, M J; Fich, M; Jenness, T; Johnstone, D; Mottram, J C; Nutter, D; Pattle, K; Pineda, J E; Quinn, C; Salji, C; Tisi, S; Walker-Smith, S; Di Francesco, J; Hogerheijde, M R; Ward-Thompson, D; Allen, L E; Cieza, L A; Dunham, M M; Harvey, P M; Stapelfeldt, K R; Bastien, P; Butner, H; Chen, M; Chrysostomou, A; Coude, S; Davis, C J; Drabek-Maunder, E; Duarte-Cabral, A; Fiege, J; Friberg, P; Friesen, R; Fuller, G A; Graves, S; Greaves, J; Gregson, J; Holland, W; Joncas, G; Kirk, J M; Knee, L B G; Mairs, S; Marsh, K; Matthews, B C; Moriarty-Schieven, G; Rawlings, J; Richer, J; Robertson, D; Rosolowsky, E; Sadavoy, S; Thomas, H; Tothill, N; Viti, S; White, G J; Wilson, C D; Wouterloot, J; Yates, J; Zhu, M

    2014-01-01

    We present SCUBA-2 450\\mu m and 850\\mu m observations of the Serpens MWC 297 region, part of the JCMT Gould Belt Survey of nearby star-forming regions. Simulations suggest that radiative feedback influences the star-formation process and we investigate observational evidence for this by constructing temperature maps. Maps are derived from the ratio of SCUBA-2 fluxes and a two component model of the JCMT beam for a fixed dust opacity spectral index of beta = 1.8. Within 40 of the B1.5Ve Herbig star MWC 297, the submillimetre fluxes are contaminated by free-free emission with a spectral index of 1.03\\pm0.02, consistent with an ultra-compact HII region and polar winds/jets. Contamination accounts for 73\\pm5 per cent and 82\\pm4 per cent of peak flux at 450\\mu m and 850\\mu m respectively. The residual thermal disk of the star is almost undetectable at these wavelengths. Young Stellar Objects are confirmed where SCUBA-2 850\\mu m clumps identified by the fellwalker algorithm coincide with Spitzer Gould Belt Survey d...

  11. Role of dust direct radiative effect on the tropical rain belt over Middle East and North Africa: A high-resolution AGCM study

    Science.gov (United States)

    Bangalath, Hamza Kunhu; Stenchikov, Georgiy

    2015-05-01

    To investigate the influence of direct radiative effect of dust on the tropical summer rain belt across the Middle East and North Africa (MENA), the present study utilizes the high-resolution capability of an Atmospheric General Circulation Model, the High-Resolution Atmospheric Model. Ensembles of Atmospheric Model Intercomparison Project style simulations have been conducted with and without dust radiative impacts, to differentiate the influence of dust on the tropical rain belt. The analysis focuses on summer season. The results highlight the role of dust-induced responses in global- and regional-scale circulations in determining the strength and the latitudinal extent of the tropical rain belt. A significant response in the strength and position of the local Hadley circulation is predicted in response to meridionally asymmetric distribution of dust and the corresponding radiative effects. Significant responses are also found in regional circulation features such as African Easterly Jet and West African Monsoon circulation. Consistent with these dynamic responses at various scales, the tropical rain belt across MENA strengthens and shifts northward. Importantly, the summer precipitation over the semiarid strip south of Sahara, including Sahel, increases up to 20%. As this region is characterized by the "Sahel drought," the predicted precipitation sensitivity to the dust loading over this region has a wide range of socioeconomic implications. Overall, the study demonstrates the extreme importance of incorporating dust radiative effects and the corresponding circulation responses at various scales, in the simulations and future projections of this region's climate.

  12. The effects of the big storm events in the first half of 2015 on the radiation belts observed by EPT/PROBA-V

    Science.gov (United States)

    Pierrard, V.; Lopez Rosson, G.

    2016-01-01

    With the energetic particle telescope (EPT) performing with direct electron and proton discrimination on board the ESA satellite PROBA-V, we analyze the high-resolution measurements of the charged particle radiation environment at an altitude of 820 km for the year 2015. On 17 March 2015, a big geomagnetic storm event injected unusual fluxes up to low radial distances in the radiation belts. EPT electron measurements show a deep dropout at L > 4 starting during the main phase of the storm, associated to the penetration of high energy fluxes at L < 2 completely filling the slot region. After 10 days, the formation of a new slot around L = 2.8 for electrons of 500-600 keV separates the outer belt from the belt extending at other longitudes than the South Atlantic Anomaly. Two other major events appeared in January and June 2015, again with injections of electrons in the inner belt, contrary to what was observed in 2013 and 2014. These observations open many perspectives to better understand the source and loss mechanisms, and particularly concerning the formation of three belts.

  13. Radiological Impact of artificial and naturally radiation sources. Report of the UNSCEAR, 2008

    International Nuclear Information System (INIS)

    Results in the report of the Scientific Committee of the United Nations for Study of the Effects of Atomic Radiations, presented in the 56th period of sessions in July 2008; values obtained from natural sources or from artificial ones are compared and, in accordance with their effects on humans. It is concluded that the most significant change in the situation, between reports, has been the increase in the medical exposure due to the increase in the number of computed tomography examinations. (author)

  14. Photostability study of commercial sunscreens submitted to artificial UV irradiation and/or fluorescent radiation.

    Science.gov (United States)

    Romanhole, Rodrigo Colina; Ataide, Janaina Artem; Cefali, Leticia Caramori; Moriel, Patricia; Mazzola, Priscila Gava

    2016-09-01

    Sunscreens contain molecules with the ability to absorb and/or reflect UVA (ultraviolet A) and UVB (ultraviolet B) radiation, thereby preventing this radiation from reaching the epidermis or dermis. Their photo stabilities after exposure to UV radiation are well known and described, but there is little data on the stability of these filters after fluorescent indoors light radiation, such as from light emitted by commercial lamps present in homes and offices. Those lamps can expose people to varying levels of UVB, UVA, visible light, and IR (infrared). This study assesses the photostability of four different commercial products containing chemical sun filters after artificial UV and fluorescent irradiation, correlating the UVB and UVA absorption efficiencies of each product against the different types of radiation. The tested products were applied on a plate of polymethylmethacrylate (PMMA) and irradiated by a solar simulator with specific filters for UVA and UVB and a commercial fluorescent light source. According to the results, three formulations did not show photostability, suffering significant changes in their UV absorption spectra, and one of the selected formulations can be considered photostable. This reinforces the importance of conducting stability studies for sunscreen formulations in different conditions, including under artificial (indoor) light exposure. PMID:27341636

  15. LEEM: A new empirical model of radiation-belt electrons in the low-Earth-orbit region

    Science.gov (United States)

    Chen, Yue; Reeves, Geoffrey; Friedel, Reiner H. W.; Thomsen, Michelle F.; Looper, Mark; Evans, David; Sauvaud, Jean-Andre

    2012-11-01

    A new empirical model of radiation-belt electrons in the low-Earth-orbit region has been developed based upon decade-long in situ observations from several low-altitude-orbiting satellites. This model—LEEM—aims to provide the electron environment conditions that a satellite would encounter in a given low Earth orbit. This model presents electron flux values for five energy ranges (0.03-2.5 MeV, 0.1-2.5 MeV, 0.3-2.5 MeV, 1.5-6 MeV, and 2.5-14 MeV) within the space below an altitude of ˜600 km. Compared to the de-facto standard empirical model of AE-8, this model not only has a better data coverage in this specific region, but also can provide statistical information on flux levels such as worst cases and occurrence percentiles instead of solely mean values. The comparison indicates that the AE-8 model not only highly overpredicts the fluxes in the inner belt region in most cases, especially for the MeV electrons, which cannot be accounted for by the widely quoted error factor of 2 for AE-8, but also is unable to reflect the observed orders of magnitude variations in electron intensities. The LEEM model is carefully validated with both in-sample and out-of-sample tests. The characteristic electron environments along the International Space Station track and other virtual orbits are given as examples and as a demonstration of the use of the model.

  16. Radiation belt electron precipitation in the upper ionosphere at middle latitudes before strong earthquakes

    CERN Document Server

    Anagnostopoulos, G; Vassiliadis, E

    2010-01-01

    In this article we present examples of a wider study of space-time correlation of electron precipitation event of the Van Allen belts with the position and time of occurrence of strong (M>6.5) earthquakes. The study is based on the analysis of observations of electron bursts (EBs) with energies 70 - 2350 keV at middle geographic latitudes, which were detected by DEMETER satellite (at an altitude of ~700 km). The EBs show a relative peak-to-background increase usually < 100, they have a time duration ~0.5 - 3 min, energy spectrum with peaks moving in higher energies as the satellite moves towards the equator, and highest energy limit <~500 keV. The EBs are observed in the presence of VLF waves. The flux-time profile of the EBs varies in East Asia and Mediterranean Sea at the similar geographic latitudes, due to the differentiation of the magnitude of the earth's magnetic field. The most important result of our study is the characteristic temporal variation of electron precipitation variation which begins...

  17. Supervised artificial neural network-based method for conversion of solar radiation data (case study: Algeria)

    Science.gov (United States)

    Laidi, Maamar; Hanini, Salah; Rezrazi, Ahmed; Yaiche, Mohamed Redha; El Hadj, Abdallah Abdallah; Chellali, Farouk

    2016-01-01

    In this study, a backpropagation artificial neural network (BP-ANN) model is used as an alternative approach to predict solar radiation on tilted surfaces (SRT) using a number of variables involved in physical process. These variables are namely the latitude of the site, mean temperature and relative humidity, Linke turbidity factor and Angstrom coefficient, extraterrestrial solar radiation, solar radiation data measured on horizontal surfaces (SRH), and solar zenith angle. Experimental solar radiation data from 13 stations spread all over Algeria around the year (2004) were used for training/validation and testing the artificial neural networks (ANNs), and one station was used to make the interpolation of the designed ANN. The ANN model was trained, validated, and tested using 60, 20, and 20 % of all data, respectively. The configuration 8-35-1 (8 inputs, 35 hidden, and 1 output neurons) presented an excellent agreement between the prediction and the experimental data during the test stage with determination coefficient of 0.99 and root meat squared error of 5.75 Wh/m2, considering a three-layer feedforward backpropagation neural network with Levenberg-Marquardt training algorithm, a hyperbolic tangent sigmoid and linear transfer function at the hidden and the output layer, respectively. This novel model could be used by researchers or scientists to design high-efficiency solar devices that are usually tilted at an optimum angle to increase the solar incident on the surface.

  18. Active Path Selection of Fluid Microcapsules in Artificial Blood Vessel by Acoustic Radiation Force

    Science.gov (United States)

    Masuda, Kohji; Muramatsu, Yusuke; Ueda, Sawami; Nakamoto, Ryusuke; Nakayashiki, Yusuke; Ishihara, Ken

    2009-07-01

    Micrometer-sized microcapsules collapse upon exposure to ultrasound. Use of this phenomenon for a drug delivery system (DDS), not only for local delivery of medication but also for gene therapy, should be possible. However, enhancing the efficiency of medication is limited because capsules in suspension diffuse in the human body after injection, since the motion of capsules in blood flow cannot be controlled. To control the behavior of microcapsules, acoustic radiation force was introduced. We detected local changes in microcapsule density by producing acoustic radiation force in an artificial blood vessel. Furthermore, we theoretically estimated the conditions required for active path selection of capsules at a bifurcation point in the artificial blood vessel. We observed the difference in capsule density at both in the bifurcation point and in alternative paths downstream of the bifurcation point for different acoustic radiation forces. Comparing the experimental results with those obtained theoretically, the conditions for active path selection were calculated from the acoustic radiation force and fluid resistance of the capsules. The possibility of controlling capsule flow towards a specific point in a blood vessel was demonstrated.

  19. 上海城市河岸带对降雨径流氮垂直去除研究%NITROGEN REMOVAL IN VERTICAL INFILTRATION OF RUNOFF BY ARTIFICIAL GREEN BELT NEAR RIPARIAN IN SHANGHAI

    Institute of Scientific and Technical Information of China (English)

    邓焕广; 王东启; 陈振楼; 周栋; 张菊

    2013-01-01

    在上海市城市河岸带人工绿地建设了微区径流场,进行了5次模拟降雨径流实验,研究了人工绿地岸带下渗流中氮浓度和去除率的时空变化.结果表明:人工绿地岸带对垂直下渗流中氮有显著的净化作用,且主要集中于土壤的0~30 cm以内,TN和NH4+去除率在39.9%和39.8%以上,NO3-+NO2去除率除11月为负值外,其余月份均在10.0%以上;在30~60 cm深度,由于土壤氮的析出导致径流中氮浓度增加,去除率降低;而60~90cm深度的去除率增加.径流场内下渗流中氮浓度具有明显的水平空间变化,随距入水端距离的增加,30 cm深度下渗流中氮浓度先上升后下降;人工绿地岸带对下渗流中氮的净化作用均随淹水时间的延长呈降低趋势,且季节变化明显,在10月和4月具有较高的去除率,0~30 cm内TN、NH4+和NO3+NO2-的去除率可分别达63.5%、89.1%和41.6%以上.%In order to study nitrogen removal in vertical infiltration of runoff by artificial green belt near urban riparian,a micro catchment area was constructed at Changfeng green belt of Suzhou River riparian.Meanwhile permeability of Changfeng green belt was measured by double ring method and soil samples were collected for analysis of physicochemical properties.In situ pore water samplers were used to collect samples of vertical infiltration at different depth in the micro catchment area,which were distributed from surface runoff flowing 1 m,11 m,18 m,21 m at depth of 30 cm,60 cm and 90 cm.3 pore water samplers were buried at each depth.The water in Suzhou River containing higher nitrogen concentrations than the corresponding type V standard values of the GB 3838-2002 National Environmental Quality Standards for Surface Water was fit to simulate runoff.Therefore,5 rainfall runoff stimulation experiments were carried out at Changfeng artificial green belt using water of Suzhou River at October,November of 2010 and April,June,August of 2011.Spatial

  20. Entropy-based artificial viscosity stabilization for non-equilibrium Grey Radiation-Hydrodynamics

    International Nuclear Information System (INIS)

    The entropy viscosity method is extended to the non-equilibrium Grey Radiation-Hydrodynamic equations. The method employs a viscous regularization to stabilize the numerical solution. The artificial viscosity coefficient is modulated by the entropy production and peaks at shock locations. The added dissipative terms are consistent with the entropy minimum principle. A new functional form of the entropy residual, suitable for the Radiation-Hydrodynamic equations, is derived. We demonstrate that the viscous regularization preserves the equilibrium diffusion limit. The equations are discretized with a standard Continuous Galerkin Finite Element Method and a fully implicit temporal integrator within the MOOSE multiphysics framework. The method of manufactured solutions is employed to demonstrate second-order accuracy in both the equilibrium diffusion and streaming limits. Several typical 1-D radiation-hydrodynamic test cases with shocks (from Mach 1.05 to Mach 50) are presented to establish the ability of the technique to capture and resolve shocks

  1. Variations in Jupiter's Radiation Belts and Synchrotron Radiation as a Result of the Impacts of Comet Shoemaker-Levy/9

    Science.gov (United States)

    Bolton, S.; Gulkis, S.; Klein, M.; Thorne, R. M.

    1995-01-01

    Changes to Jupiter's synchrotron radiation following the impact of Comet Shoemaker-Levy/9 are reported. Also, the consequences are reported for three possible mechanisms that might have caused those changes.

  2. MDS G(N) fast differentiation between natural and artificial gamma radiation with a new class of mobile instruments

    International Nuclear Information System (INIS)

    A State-of-the-Art tool used for detecting and tracking artificial gamma radiation out of a helicopter or a vehicle is the MDS G(N) - Mobile Detection System. A highly sensitive scintillation detector detects a significant artificial gamma radiation on the ground even if the helicopter is travelling at high speed. The GPS-aided system visualizes the measured values on a moveable map displayed on the screen of a notebook every second. The colours of the continuously entered points do represent adjustable alarm thresholds. This way, location and intensity of an unknown radioactive source or a radioactive contamination can be determined very quickly. The NBR-technology (Natural Background Rejection) which is used here leads to expressive measurement results differentiating between artificial and natural gamma radiation. Additional He-3 detectors allow simultaneously the detection of neutrons. The NBR principle - developed by Thermo Scientific - stands out for its very short response times. Thus, artificial radiation can be detected reliably within seconds - even when the unit is operated by untrained staff. Unlike traditional analytic measuring techniques, the NBR method is able to detect artificial radiation sources hidden or strongly shielded gamma sources clearly from the natural background radiation. The measuring range from 1 nSv/h to 20 ?Sv/h and is extended to 1 Sv/h with a Geiger Mueller counting tube. The sensitivity amounts to max. 20000 cps (referred to 1 ?Sv/h for Cs-137). The NBR- technique is well-proven and tested for: tracking hidden radiation sources, even such ones with low activity or which are shielded, detection of artificial radiation portions in the range of the natural background, reliably measuring the ambient equivalent dose rate in the range of the natural background, fast detection of artificial radioactivity out of helicopters and vehicles.(author)

  3. Wave energy budget analysis in the Earth's radiation belts uncovers a missing energy

    OpenAIRE

    Artemyev, A.V.; Agapitov, O. V.; D. Mourenas; Krasnoselskikh, V. V.; Mozer, F. S.

    2015-01-01

    Whistler-mode emissions are important electromagnetic waves pervasive in the Earth's magnetosphere, where they continuously remove or energize electrons trapped by the geomagnetic field, controlling radiation hazards to satellites and astronauts and the upper-atmosphere ionization or chemical composition. Here, we report an analysis of 10-year Cluster data, statistically evaluating the full wave energy budget in the Earth's magneto-sphere, revealing that a significant fraction of the energy c...

  4. Pitch-angle diffusion of electrons through growing and propagating along a magnetic field electromagnetic wave in Earth's radiation belts

    International Nuclear Information System (INIS)

    The diffusion of electrons via a linearly polarized, growing electromagnetic (EM) wave propagating along a uniform magnetic field is investigated. The diffusion of electrons that interact with the growing EM wave is investigated through the autocorrelation function of the parallel electron acceleration in several tens of electron gyration timescales, which is a relatively short time compared with the bounce time of electrons between two mirror points in Earth's radiation belts. Furthermore, the pitch-angle diffusion coefficient is derived for the resonant and non-resonant electrons, and the effect of the wave growth on the electron diffusion is discussed. The results can be applied to other problems related to local acceleration or the heating of electrons in space plasmas, such as in the radiation belts

  5. Direct observation of radiation belt electrons precipitation by the controlled injection of VLF signals from a ground-based transmitter

    International Nuclear Information System (INIS)

    Radiation belt electrons precipitated by controlled injection of VLF signals from a ground based transmitter have been directly observed for the first time. These observations were part of the SEEP (Stimulated Emission of Energetic Particles) experiment conducted during May-December 1982. Key elements of SEEP were the controlled modulation of VLF transmitters and a sensitive low altitude satellite payload to detect the precipitation. An outstanding example of time-correlated wave and particle data occurred from 8680 to 8740 seconds. U. T. on 17 August 1982 when the satellite passed near the VLF transmitter at Cutler, Maine (NAA) as it was being modulated with a repeated ON (3--s)/OFF (2--s) pattern. During each of twelve consecutive pulses from the transmitter the electron counting rate increased significantly after start of the ON period and reached a maximum about 2 seconds later. The measured energy spectra revealed that approximately 15 to 50 percent of the enhanced electron flux was concentrated near the resonant energies for first order cyclotron interactions occurring close to the magnetic equator with the nearly monochromatic waves emitted from the transmitter

  6. On the numerical simulation of particle dynamics in the radiation belt: 1. Implicit and semi-implicit schemes

    Science.gov (United States)

    Camporeale, E.; Delzanno, G. L.; Zaharia, S.; Koller, J.

    2013-06-01

    The particle dynamics in the Earth's radiation belt is generally modeled by means of a two-dimensional diffusion equation for the particle distribution function in energy and pitch angle. The goal of this paper is to survey and compare different numerical schemes for the solution of the diffusion equation, and to outline the optimal strategy from a numerical point of view. We focus on the general (and more computationally challenging) case where the mixed terms in the diffusion tensor are retained. In Part 1, we compare fully implicit and semi-implicit schemes. For the former, we have analyzed a direct solver based on a LU decomposition routine for sparse matrices, and an iterative incomplete LU preconditioned Generalized Minimal REsidual solver. For the semi-implicit scheme, we have studied an alternating direction implicit scheme. We present a convergence study for a realistic case that shows that the time step and grid size are strongly constrained by the desired accuracy of the solution. We show that the fully implicit scheme is to be preferred in most cases as the more computationally efficient.

  7. On the computational efficiency of particle dynamics simulations in the radiation belt: comparison between implicit and semi-implicit schemes

    Science.gov (United States)

    Camporeale, E.; Delzanno, G.; Zaharia, S. G.; Koller, J.

    2012-12-01

    The particle dynamics in the Earth's radiation belt is generally modeled by means of a two-dimensional diffusion equation for the particle distribution function in energy and pitch angle. In this work we survey and compare different numerical schemes for the solution of the diffusion equation, with the goal of outlining which is the optimal strategy from a numerical point of view. We focus on the general (and more computationally challenging) case where the mixed terms in the diffusion tensor are retained. We compare fully-implicit and semi-implicit schemes. For the former we have analyzed a direct solver based on a LU decomposition routine for sparse matrices, and an iterative ILU-preconditioned GMRES. For the semi-implicit scheme we have studied an Alternating Direction Implicit scheme. We present a convergence study for a realistic case that shows that the timestep and grid size are strongly constrained by the desired accuracy of the solution. We show that the fully-implicit scheme is to be preferred in most cases as the more computationally efficient.

  8. Studies of ionising radiation induced bystander effects in 3D artificial tissue system and applications for radiation protection

    International Nuclear Information System (INIS)

    The universality of the target theory of radiation-induced effects is challenged by observations on non-targeted effects such as bystander effects. Essential features of non-targeted effects are that they do not require direct nuclear exposure by radiation and they are particularly significant at low doses. This new evidence suggests a need for a new paradigm in radiation biology. The new paradigm should cover both the classical (targeted) and the non-targeted effects. The bystander effect cannot be comprehensively explained on the basis of a single cell reaction. It is well known that an organism is composed of different cell types that interact as functional units in a way to maintain normal tissue function. Therefore the radiation response is not simply the sum of cellular responses as assumed in classical radiobiology, predominantly from studies using cell cultures. Experimental models, which maintain tissue-like intercellular cell signalling and 3D structure, are essential for proper understanding of the bystander effect. Our work relates to experimentation with novel 3D artificial human tissue systems available from MatTek Corporation (Boston, USA). Air-liquid interface culture technique is used to grow artificial tissues, which allow to model conditions present in vivo. The Gray Cancer Institute (Northwood, UK) charged particle microbeam was used to irradiate tissue samples in a known pattern with a known number of 3He2+ particles or protons. After irradiation, the tissues models were incubated for 3 days, fixed in 10 % NBF, paraffin embedded and then sliced into 5 μm histological sections located at varying distances from the plane of the irradiated cells. We studied in situ apoptosis and markers of differentiation. Significantly elevated bystander induced apoptosis was observed with 3'-OH DNA end-labelling based technique in 3D artificial tissue systems. Our results also suggested an importance of proliferation and differentiation status for bystander

  9. Antimicrobial Effects of Ionizing Radiation on Artificially and Naturally Contaminated Cacao Beans

    OpenAIRE

    Restaino, L; Myron, J. J. J.; Lenovich, L M; Bills, S.; Tscherneff, K.

    1984-01-01

    With an initial microbial level of ca. 107 microorganisms per g of Ivory Coast cacao beans, 5 kGy of gamma radiation under an atmosphere of air reduced the microflora per g by 2.49 and 3.03 logs at temperatures of 35 and 50°C, respectively. Bahia cacao beans were artificially contaminated with dried spores of Aspergillus flavus and Penicillium citrinum, giving initial fungal levels of 1.9 × 104 and 1.4 × 103 spores per g of whole Bahia cacao beans, respectively. The average D10 values for A. ...

  10. Association of radiation belt electron enhancements with earthward penetration of Pc5 ULF waves: a case study of intense 2001 magnetic storms

    Science.gov (United States)

    Georgiou, M.; Daglis, I. A.; Zesta, E.; Balasis, G.; Mann, I. R.; Katsavrias, C.; Tsinganos, K.

    2015-11-01

    Geospace magnetic storms, driven by the solar wind, are associated with increases or decreases in the fluxes of relativistic electrons in the outer radiation belt. We examine the response of relativistic electrons to four intense magnetic storms, during which the minimum of the Dst index ranged from -105 to -387 nT, and compare these with concurrent observations of ultra-low-frequency (ULF) waves from the trans-Scandinavian IMAGE magnetometer network and stations from multiple magnetometer arrays available through the worldwide SuperMAG collaboration. The latitudinal and global distribution of Pc5 wave power is examined to determine how deep into the magnetosphere these waves penetrate. We then investigate the role of Pc5 wave activity deep in the magnetosphere in enhancements of radiation belt electrons population observed in the recovery phase of the magnetic storms. We show that, during magnetic storms characterized by increased post-storm electron fluxes as compared to their pre-storm values, the earthward shift of peak and inner boundary of the outer electron radiation belt follows the Pc5 wave activity, reaching L shells as low as 3-4. In contrast, the one magnetic storm characterized by irreversible loss of electrons was related to limited Pc5 wave activity that was not intensified at low L shells. These observations demonstrate that enhanced Pc5 ULF wave activity penetrating deep into the magnetosphere during the main and recovery phase of magnetic storms can, for the cases examined, distinguish storms that resulted in increases in relativistic electron fluxes in the outer radiation belts from those that did not.

  11. Simultaneous quiet time observations of energetic radiation belt protons and helium ions - The equatorial alpha/p ratio near 1 MeV

    Science.gov (United States)

    Fritz, T. A.; Spjeldvik, W. N.

    1979-01-01

    Simultaneous monitoring of energetic helium ions and protons in the earth's radiation belts has been conducted with Explorer 45 in the immediate vicinity of the equatorial plane. Protons were measured from less than 1 keV to 1.6 MeV and also above 3.3 MeV in a channel responsive up to 22 MeV; helium ions were monitored in three passbands: 910 keV to 3.15 MeV, 590 to 910 keV, and 2.0 to 3.99 MeV. Alpha/proton flux ratios were found to vary significantly with energy and location in the radiation belts. At equal energy per nucleon a range of variability for alpha/p from 0.0001 to well above 0.001 was found, and at equal energy per ion the corresponding variability was from 0.001 to above 10. The latter findings emphasize the relative importance of the very energetic helium ions in the overall radiation belt ion populations.

  12. Hydrogen and helium isotope inner radiation belts in the Earth's magnetosphere

    Directory of Open Access Journals (Sweden)

    G. I. Pugacheva

    Full Text Available Radial transport theory for inner radiation zone MeV ions has been extended by combining radial diffusive transport and losses due to Coulomb friction with local generation of D, T and 3He ions from nuclear reactions taking place on the inner edge of the inner radiation zone. Based on interactions between high energy trapped protons and upper atmospheric constituents we have included a nuclear reaction yield D, T and 3He flux source that was numerically derived from a nuclear reaction model code originally developed at the Institute of Nuclear Researches in Moscow, Russia. Magnetospheric transport computations have been made covering the L-shell range L=1.0–1.6. The resulting MeV energy D, T and 3He ion flux distributions show a strong influence of the local nuclear source mechanism on the inner zone energetic D, T and 3He ion content.

    Key words: Atmospheric composition and structure (Thermosphere-composition and chemistry · Magnetospheric physics (Energetic particles · trapped.

  13. An artificial-vision responsive to patient motions during computer controlled radiation therapy

    International Nuclear Information System (INIS)

    Purpose/Objectives: Automated precision radiotherapy using multiple conformal and modulated beams, requires monitoring of patient movements during irradiation. Immobilizers relying on patient cooperating in cradles have somewhat reduced positional uncertainties, but others including breathing are largely unknown. We built an artificial vision (AV) device for real-time vision of patient movements, their tracking and quantification. Method and Materials: The Artificial Vision System's 'acuity' and 'reflex' were evaluated in terms of imaged skin spatial resolutions and temporal dispersions measured using a mannequin and a fiduciated harmonic oscillator placed at 100cm isocenter. The device traced skin motion even in poorly lighted rooms without use of explicit skin fiduciation, or using standard radiotherapy skin tattoos. Results: The AV system tracked human skin at vision rates approaching 30Hz and sensitivity of 2mm. It successfully identified and tracked independent skin marks, either natural tattoos or artificial fiducials. Three alert levels triggered when patient movement exceeded preset displacements (2mm/30Hz), motion velocities (5m/sec) or acceleration (2m/sec2). Conclusion: The AV system trigger should suit for patient ventilatory gating and safety interlocking of treatment accelerators, in order to modulate, interrupt, or abort radiation during dynamic therapy

  14. Cancer risk at low doses of ionizing radiation: artificial neural networks inference from atomic bomb survivors.

    Science.gov (United States)

    Sasaki, Masao S; Tachibana, Akira; Takeda, Shunichi

    2014-05-01

    Cancer risk at low doses of ionizing radiation remains poorly defined because of ambiguity in the quantitative link to doses below 0.2 Sv in atomic bomb survivors in Hiroshima and Nagasaki arising from limitations in the statistical power and information available on overall radiation dose. To deal with these difficulties, a novel nonparametric statistics based on the 'integrate-and-fire' algorithm of artificial neural networks was developed and tested in cancer databases established by the Radiation Effects Research Foundation. The analysis revealed unique features at low doses that could not be accounted for by nominal exposure dose, including (i) the presence of a threshold that varied with organ, gender and age at exposure, and (ii) a small but significant bumping increase in cancer risk at low doses in Nagasaki that probably reflects internal exposure to (239)Pu. The threshold was distinct from the canonical definition of zero effect in that it was manifested as negative excess relative risk, or suppression of background cancer rates. Such a unique tissue response at low doses of radiation exposure has been implicated in the context of the molecular basis of radiation-environment interplay in favor of recently emerging experimental evidence on DNA double-strand break repair pathway choice and its epigenetic memory by histone marking. PMID:24366315

  15. A radiation-induced breast cancer following artificial pneumothorax therapy for pulmonary tuberculosis

    International Nuclear Information System (INIS)

    A case of radiation-induced breast cancer in a woman who had been fluoroscopied repeatedly for control of pneumothorax for pulmonary tuberculosis 35 years before is reported. The breast tissue presumably received about 136 rads or less in three and a half years. In Japan, both prospective and retrospective surveies following multiple fluoroscopies during artificial pneumothorax collaps therapy have failed to show an increase in the risk of subsequent development of primary breast cancer. The dose given to breast tissues in Japanese patients was generally far less than that in the MacKenzie's series. A radiation-induced breast cancer in Japanese literature has not yet been reported. It seems that the lesser doses may explain the reason of this fact. (auth.)

  16. Natural and artificial ultraviolet radiation and skin cancer risk: what's new? Proceedings of the SFRP Non-ionizing radiation section round table

    International Nuclear Information System (INIS)

    The Non-ionizing radiation section of the French Society of Radiation Protection (SFRP) organized a technical meeting on the current knowledge of UV mutagenicity mechanisms, on professional exposures and on the risks linked with artificial tanning and their prevention. This document brings together the 3 available presentations (slides) of the talks given at the meeting: 1 - UV induction of DNA photoproducts: recent data (Thierry DOUKI, CEA Grenoble); 2 - Professional exposure to UV radiations (Mathieu BONIOL, IPRI); 3 - Artificial tanning: a major but avoidable public health problem (Jean-Francois DORE, Centre de Recherche en Cancerologie)

  17. An artificial neural network ensemble model for estimating global solar radiation from Meteosat satellite images

    International Nuclear Information System (INIS)

    An optimized artificial neural network ensemble model is built to estimate daily global solar radiation over large areas. The model uses clear-sky estimates and satellite images as input variables. Unlike most studies using satellite imagery based on visible channels, our model also exploits all information within infrared channels of the Meteosat 9 satellite. A genetic algorithm is used to optimize selection of model inputs, for which twelve are selected – eleven 3-km Meteosat 9 channels and one clear-sky term. The model is validated in Andalusia (Spain) from January 2008 through December 2008. Measured data from 83 stations across the region are used, 65 for training and 18 independent ones for testing the model. At the latter stations, the ensemble model yields an overall root mean square error of 6.74% and correlation coefficient of 99%; the generated estimates are relatively accurate and errors spatially uniform. The model yields reliable results even on cloudy days, improving on current models based on satellite imagery. - Highlights: • Daily solar radiation data are generated using an artificial neural network ensemble. • Eleven Meteosat channels observations and a clear sky term are used as model inputs. • Model exploits all information within infrared Meteosat channels. • Measured data for a year from 83 ground stations are used. • The proposed approach has better performance than existing models on daily basis

  18. Comparison of artificial intelligence methods and empirical equations to estimate daily solar radiation

    Science.gov (United States)

    Mehdizadeh, Saeid; Behmanesh, Javad; Khalili, Keivan

    2016-08-01

    In the present research, three artificial intelligence methods including Gene Expression Programming (GEP), Artificial Neural Networks (ANN) and Adaptive Neuro-Fuzzy Inference System (ANFIS) as well as, 48 empirical equations (10, 12 and 26 equations were temperature-based, sunshine-based and meteorological parameters-based, respectively) were used to estimate daily solar radiation in Kerman, Iran in the period of 1992-2009. To develop the GEP, ANN and ANFIS models, depending on the used empirical equations, various combinations of minimum air temperature, maximum air temperature, mean air temperature, extraterrestrial radiation, actual sunshine duration, maximum possible sunshine duration, sunshine duration ratio, relative humidity and precipitation were considered as inputs in the mentioned intelligent methods. To compare the accuracy of empirical equations and intelligent models, root mean square error (RMSE), mean absolute error (MAE), mean absolute relative error (MARE) and determination coefficient (R2) indices were used. The results showed that in general, sunshine-based and meteorological parameters-based scenarios in ANN and ANFIS models presented high accuracy than mentioned empirical equations. Moreover, the most accurate method in the studied region was ANN11 scenario with five inputs. The values of RMSE, MAE, MARE and R2 indices for the mentioned model were 1.850 MJ m-2 day-1, 1.184 MJ m-2 day-1, 9.58% and 0.935, respectively.

  19. Real time determination of dose radiation through artificial intelligence and virtual reality

    International Nuclear Information System (INIS)

    In the last years, a virtual environment of Argonauta research reactor, sited in the Instituto de Engenharia Nuclear (Brazil), has been developed. Such environment, called here Argonauta Virtual (AV), is a 3D model of the reactor hall, in which virtual people (avatar) can navigate. In AV, simulations of nuclear sources and doses are possible. In a recent work, a real time monitoring system (RTMS) was developed to provide (by means of Ethernet TCP/IP) the information of area detectors situated in the reactor hall. Extending the scope of AV, this work is intended to provide a continuous determination of gamma radiation dose in the reactor hall, based in several monitored parameters. To accomplish that a module based in artificial neural network (ANN) was developed. The ANN module is able to predict gamma radiation doses using as inputs: the avatar position (from virtual environment), the reactor power (from RTMS) and information of fixed area detectors (from RTMS). The ANN training data has been obtained by measurements of gamma radiation doses in a mesh of points, with previously defined positions, for different power levels. Through the use of ANN it is possible to estimate, in real time, the dose received by a person at any position in Argonauta reactor hall. Such approach allows tasks simulations and training of people inside the AV system, without exposing them to radiation effects. (author)

  20. SHORT-TERM SOLAR RADIATION FORECASTING BY USING AN ITERATIVE COMBINATION OF WAVELET ARTIFICIAL NEURAL NETWORKS

    Directory of Open Access Journals (Sweden)

    Julio Cesar Royer

    2016-03-01

    Full Text Available The information provided by accurate forecasts of solar energy time series are considered essential for performing an appropriate prediction of the electrical power that will be available in an electric system, as pointed out in Zhou et al. (2011. However, since the underlying data are highly non-stationary, it follows that to produce their accurate predictions is a very difficult assignment. In order to accomplish it, this paper proposes an iterative Combination of Wavelet Artificial Neural Networks (CWANN which is aimed to produce short-term solar radiation time series forecasting. Basically, the CWANN method can be split into three stages: at first one, a decomposition of level p, defined in terms of a wavelet basis, of a given solar radiation time series is performed, generating r+1 Wavelet Components (WC; at second one, these r+1 WCs are individually modeled by the k different ANNs, where k>5, and the 5 best forecasts of each WC are combined by means of another ANN, producing the combined forecasts of WC; and, at third one, the combined forecasts WC are simply added, generating the forecasts of the underlying solar radiation data. An iterative algorithm is proposed for iteratively searching for the optimal values for the CWANN parameters, as we will see. In order to evaluate it, ten real solar radiation time series of Brazilian system were modeled here. In all statistical results, the CWANN method has achieved remarkable greater forecasting performances when compared with a traditional ANN (described in Section 2.1.

  1. Cancer risk at low doses of ionizing radiation. Artificial neural networks inference from atomic bomb survivors

    International Nuclear Information System (INIS)

    Cancer risk at low doses of ionizing radiation remains poorly defined because of ambiguity in the quantitative link to doses below 0.2 Sv in atomic bomb survivors in Hiroshima and Nagasaki arising from limitations in the statistical power and information available on overall radiation dose. To deal with these difficulties, a novel nonparametric statistics based on the ‘integrate-and-fire’ algorithm of artificial neural networks was developed and tested in cancer databases established by the Radiation Effects Research Foundation. The analysis revealed unique features at low doses that could not be accounted for by nominal exposure dose, including (1) the presence of a threshold that varied with organ, gender and age at exposure, and (2) a small but significant bumping increase in cancer risk at low doses in Nagasaki that probably reflects internal exposure to 239Pu. The threshold was distinct from the canonical definition of zero effect in that it was manifested as negative excess relative risk, or suppression of background cancer rates. Such a unique tissue response at low doses of radiation exposure has been implicated in the context of the molecular basis of radiation–environment interplay in favor of recently emerging experimental evidence on DNA double-strand break repair pathway choice and its epigenetic memory by histone marking. (author)

  2. Real time determination of dose radiation through artificial intelligence and virtual reality

    International Nuclear Information System (INIS)

    In the last years, a virtual environment of Argonauta research reactor, sited in the Instituto de Engenharia Nuclear (Brazil), has been developed. Such environment, called here Argonauta Virtual (AV), is a 3D model of the reactor hall, in which virtual people (avatar) can navigate. In AV, simulations of nuclear sources and doses are possible. In a recent work, a real time monitoring system (RTMS) was developed to provide (by means of Ethernet TCP/I P) the information of area detectors situated in the reactor hall. Extending the scope of AV, this work is intended to provide a continuous determination of gamma radiation dose in the reactor hall, based in several monitored parameters. To accomplish that a module based in artificial neural network (ANN) was developed. The ANN module is able to predict gamma radiation doses using as inputs: the avatar position (from virtual environment), the reactor power (from RTMS) and information of fixed area detectors (from RTMS). The ANN training data has been obtained by measurements of gamma radiation doses in a mesh of points, with previously defined positions, for different power levels. Through the use of ANN it is possible to estimate, in real time, the dose received by a person at any position in Argonauta reactor hall. Such approach allows tasks simulations and training of people inside the AV system, without exposing them to radiation effects. (author)

  3. Prediction of monthly mean daily global solar radiation using Artificial Neural Network

    Indian Academy of Sciences (India)

    V Sivamadhavi; R Samuel Selvaraj

    2012-12-01

    In this study, a multilayer feed forward (MLFF) neural network based on back propagation algorithm was developed, trained, and tested to predict monthly mean daily global radiation in Tamil Nadu, India. Various geographical, solar and meteorological parameters of three different locations with diverse climatic conditions were used as input parameters. Out of 565 available data, 530 were used for training and the rest were used for testing the artificial neural network (ANN). A 3-layer and a 4-layer MLFF networks were developed and the performance of the developed models was evaluated based on mean bias error, mean absolute percentage error, root mean squared error and Student’s -test. The 3-layer MLFF network developed in this study did not give uniform results for the three chosen locations. Hence, a 4-layer MLFF network was developed and the average value of the mean absolute percentage error was found to be 5.47%. Values of global radiation obtained using the model were in excellent agreement with measured values. Results of this study show that the designed ANN model can be used to estimate monthly mean daily global radiation of any place in Tamil Nadu where measured global radiation data are not available.

  4. Towards OpenGGCM 4.0. Simulating the global magnetosphere with ring current, radiation belts, plasmasphere, and hall MHD

    International Nuclear Information System (INIS)

    Complete text of publication follows. The OpenGGCM is a global numerical model of geospace, covering the Earth's magnetosphere, ionosphere, and thermosphere. Although housed at the University of New Hampshire, it is a community model that is available to any researcher for runs on demand at the Community Coordinated Modeling Center (CCMC, http://ccmc.gsfc.nasa.gov). Like any numerical model it is not perfect and thus subject to continuous development work to add more physics, make it more robust, and to improve performance. In this presentation we will outline a number of ongoing improvements to the model. First, the OpenGGCM is being coupled with the RCM (Rice Convection Model) and CRCM (Comprehensive Ring Current Model) models of the inner magnetosphere. This coupling should improve the realism of the model close to Earth, where particle drift physics is important. The coupling is in both directions, where the RC models receive the ionosphere potential, the magnetic topology, and plasma parameters at the boundaries from the OpenGGCM, and in the opposite direction the OpenGGCM receives pressure and density in the inner magnetosphere, as well as field aligned current and e- precipitation. Second, we couple the NASA/GSFC RBM (Radiation Belt Model) to the OpenGGCM. In this case the coupling is only one way, i.e., the RBM receives particle sources and magnetic topology from the OpenGGCM. Third, we replace the current ionosphere-thermosphere module, CTIM, with the new GT-GIP, which also includes a self-consistent plasmasphere model. Finally, we replace the MHD formalism in the magnetosphere with a Hall-MHD formalism, which is primarily of importance for magnetic reconnection. The new upgraded model will eventually become version 4.0 at the CCMC.

  5. Radiological impact of natural and artificial sources of ionizing radiation. Report UNSCEAR 2000

    International Nuclear Information System (INIS)

    The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) was established by the General Assembly in 1995. It has the mandate to assess the levels and effects of ionizing radiation. During the last years UNSCEAR has undertaken a broad review of the natural and artificial sources of ionizing radiation. The results of these evaluations have been presented in a Report to the General Assembly with Scientific Annexes including extensive data for the world community (Report UNSCEAR 2000). The greatest contribution to radiation exposure comes from natural background sources. There are considerable variation in the exposures of the population depending on the altitude and latitude, characteristics of the soil and diet and the construction and ventilation features of houses. The global annual average per caput is 2.4 mSv with typical range 1 to 10 mSv. The next largest component comes from medical radiation examinations and treatments with an annual average of 0.4 mSv ranging from 0.04 to 1.0 mSv depending on the level o f medical care. The man-made practices, activities, and events in which radionuclides are released to the environment are always of much concern, but usually they contribute quite low to radiation exposure to humans. Atmospheric testing caused the greatest releases but nowadays very low residual annual levels of exposures persist (0.005 mSv). Nuclear Power production is responsible for only very low exposure and may reach in the future an average annual level of 0.0002 mSv. (Author)

  6. Effects of γ-radiation on the fungus Alternaria alternata in artificially inoculated cereal samples

    International Nuclear Information System (INIS)

    The objective of this study was to evaluate the effects of different γ-radiation doses on the growth of Alternaria alternata in artificially inoculated cereal samples. Seeds and grains were divided into four groups: Control Group (not irradiated), and Groups 1, 2 and 3, inoculated with an A. alternata spore suspension (1x106 spores/mL) and exposed to 2, 5 and 10 kGy, respectively. Serial dilutions of the samples were prepared and seeded on DRBC (dichloran rose bengal chloramphenicol agar) and DCMA (dichloran chloramphenicol malt extract agar) media, after which the number of colony-forming units per gram was determined in each group. In addition, fungal morphology after irradiation was analyzed by scanning electron microscopy (SEM). The results showed that ionizing radiation at a dose of 5 kGy was effective in reducing the growth of A. alternata. However, a dose of 10 kGy was necessary to inhibit fungal growth completely. SEM made it possible to visualize structural alterations induced by the different γ-radiation doses used.

  7. Modeling of solar radiation using remote sensing and artificial neural network in Turkey

    International Nuclear Information System (INIS)

    Artificial neural networks (ANNs) were used to estimate solar radiation in Turkey (26-45oE, 36-42oN) using geographical and satellite-estimated data. In order to train the Generalized regression neural network (GRNN) geographical and satellite-estimated data for the period from January 2002 to December 2002 from 19 stations spread over Turkey were used in training (ten stations) and testing (nine stations) data. Latitude, longitude, altitude, surface emissivity for ε4, surface emissivity for ε5, and land surface temperature are used in the input layer of the network. Solar radiation is the output. Root Mean Square Error (RMSE) and correlation coefficient (R2) between the estimated and measured values for monthly mean daily sum with ANN values have been found as 0.1630 MJ/m2 and 95.34% (training stations), 0.3200 MJ/m2 and 93.41% (testing stations), respectively. Since these results are good enough it was concluded that the developed GRNN tool can be used to predict the solar radiation in Turkey.

  8. An optimisation methodology of artificial neural network models for predicting solar radiation: a case study

    Science.gov (United States)

    Rezrazi, Ahmed; Hanini, Salah; Laidi, Maamar

    2016-02-01

    The right design and the high efficiency of solar energy systems require accurate information on the availability of solar radiation. Due to the cost of purchase and maintenance of the radiometers, these data are not readily available. Therefore, there is a need to develop alternative ways of generating such data. Artificial neural networks (ANNs) are excellent and effective tools for learning, pinpointing or generalising data regularities, as they have the ability to model nonlinear functions; they can also cope with complex `noisy' data. The main objective of this paper is to show how to reach an optimal model of ANNs for applying in prediction of solar radiation. The measured data of the year 2007 in Ghardaïa city (Algeria) are used to demonstrate the optimisation methodology. The performance evaluation and the comparison of results of ANN models with measured data are made on the basis of mean absolute percentage error (MAPE). It is found that MAPE in the ANN optimal model reaches 1.17 %. Also, this model yields a root mean square error (RMSE) of 14.06 % and an MBE of 0.12. The accuracy of the outputs exceeded 97 % and reached up 99.29 %. Results obtained indicate that the optimisation strategy satisfies practical requirements. It can successfully be generalised for any location in the world and be used in other fields than solar radiation estimation.

  9. Effects of {gamma}-radiation on the fungus Alternaria alternata in artificially inoculated cereal samples

    Energy Technology Data Exchange (ETDEWEB)

    Braghini, R. [Departamento de Microbiologia, Instituto de Ciencias Biomedicas II, Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 1374, CEP 05508-900 Sao Paulo (Brazil)], E-mail: raquelbraghini@yahoo.com.br; Pozzi, C.R. [Instituto de Zootecnia, Rua Heitor Penteado 56, CEP 13460-000, Nova Odessa, Sao Paulo (Brazil); Aquino, S. [Instituto Adolfo Lutz, Av. Dr. Arnaldo, 355 , CEP 01246-902, Sao Paulo (Brazil); Rocha, L.O.; Correa, B. [Departamento de Microbiologia, Instituto de Ciencias Biomedicas II, Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 1374, CEP 05508-900 Sao Paulo (Brazil)

    2009-09-15

    The objective of this study was to evaluate the effects of different {gamma}-radiation doses on the growth of Alternaria alternata in artificially inoculated cereal samples. Seeds and grains were divided into four groups: Control Group (not irradiated), and Groups 1, 2 and 3, inoculated with an A. alternata spore suspension (1x10{sup 6} spores/mL) and exposed to 2, 5 and 10 kGy, respectively. Serial dilutions of the samples were prepared and seeded on DRBC (dichloran rose bengal chloramphenicol agar) and DCMA (dichloran chloramphenicol malt extract agar) media, after which the number of colony-forming units per gram was determined in each group. In addition, fungal morphology after irradiation was analyzed by scanning electron microscopy (SEM). The results showed that ionizing radiation at a dose of 5 kGy was effective in reducing the growth of A. alternata. However, a dose of 10 kGy was necessary to inhibit fungal growth completely. SEM made it possible to visualize structural alterations induced by the different {gamma}-radiation doses used.

  10. Identification of Age, Temperature and Radiation Effect on Ferritic Steel Microstructure Based on Artificial Intelligence

    International Nuclear Information System (INIS)

    In the construction of nuclear installation, it is important to know the material condition used on it. Considering mechanical properties of these materials, there are some material change affected by ageing, temperature and radiation. For some years, austenitic stainless steel are used as a fuel cladding in fast breeder reactor. However this material will not sufficiently competitive from economic point of view for the next year. Experiment result on ferritic steel gave information of stronger structural properties compared to austenitic stainless steel. Modeling and simulation will support further identification of this material changing caused by such effects. Pattern recognition of these changes base on artificial intelligence is expected to support the research and development activities on nuclear structure materials. Material structure pattern of these materials, observed by SEM, are converted using image processing system. Its characteristic is then analyzed with principal component using perception method, which usually used on identifying and learning neural network system based on artificial intelligence. Specific design and input are needed to identify the change of material structure pattern before and after any applied effect. In this paper, simulation of changing identification on three types ferritic steel F17(17 Cr), EM 12 (9 CR-2 MoNbV), and EMI 0 (9 Cr-I Mo) were done. The microstructure data before and after effect are taken from some references. The whole pattern recognition process are done using MATLAB software package. (author)

  11. Antimicrobial effects of ionizing radiation on artificially and naturally contaminated cacao beans

    International Nuclear Information System (INIS)

    With an initial microbial level of ca. 107 microorganisms per g of Ivory Coast cacao beans, 5 kGy of gamma radiation from a Co60 source under an atmosphere of air reduced the microflora per g by 2.49 and 3.03 logs at temperatures of 35 and 500C, respectively. Bahia cacao beans were artificially contaminated with dried spores of Aspergillus flavus and Penicillium citrinum, giving initial fungal levels of 1.9 x 104 and 1.4 x 103 spores per g of whole Bahia cacao beans, respectively. The average D10 values for A. flavus and P. citrinum spores on Bahia cacao beans were 0.66 and 0.88 kGy, respectively. 12 references

  12. ARTIFICIAL NEURAL NETWORK AND WAVELET DECOMPOSITION IN THE FORECAST OF GLOBAL HORIZONTAL SOLAR RADIATION

    Directory of Open Access Journals (Sweden)

    Luiz Albino Teixeira Júnior

    2015-04-01

    Full Text Available This paper proposes a method (denoted by WD-ANN that combines the Artificial Neural Networks (ANN and the Wavelet Decomposition (WD to generate short-term global horizontal solar radiation forecasting, which is an essential information for evaluating the electrical power generated from the conversion of solar energy into electrical energy. The WD-ANN method consists of two basic steps: firstly, it is performed the decomposition of level p of the time series of interest, generating p + 1 wavelet orthonormal components; secondly, the p + 1 wavelet orthonormal components (generated in the step 1 are inserted simultaneously into an ANN in order to generate short-term forecasting. The results showed that the proposed method (WD-ANN improved substantially the performance over the (traditional ANN method.

  13. Neural Network on Photodegradation of Octylphenol using Natural and Artificial UV Radiation

    Directory of Open Access Journals (Sweden)

    Lorentz JÄNTSCHI

    2011-09-01

    Full Text Available The present paper comes up with an experimental design meant to point out the factors interferingin octylphenol’s degradation in surface waters under solar radiation, underlining each factor’sinfluence on the process observable (concentration of p-octylphenol. Multiple linear regressionanalysis and artificial neural network (Multi-Layer Perceptron type were applied in order to obtaina mathematical model capable to explain the action of UV-light upon synthetic solutions of OP inultra-pure water (MilliQ type. Neural network proves to be the most efficient method in predictingthe evolution of OP concentration during photodegradation process. Thus, determination in neuralnetwork’s case has almost double value versus the regression analysis.

  14. Artificial neural network based daily local forecasting for global solar radiation

    International Nuclear Information System (INIS)

    Highlights: • A new method for local forecasting of daily global solar radiation is proposed. • The model combines the artificial neural networks and the special modelling. • The model exploits weather forecasts provided by specialized agency. • The model’s forecasts were compared to measured data for two locations. • The developed model estimates daily solar radiation with satisfactory accuracy. - Abstract: When a part of the power is generated by grid connected photovoltaic installations, an effective global solar irradiation (GSI) forecasting tool becomes a must to ensure the quality and the security of the electrical grid. GSI forecasts allow the quantification of generated photovoltaic (PV) power and helps electrical grid operators anticipate problems related to the nature of PV power and the planning for adequate solutions and decisions. In this study, a new methodology for local forecasting of daily global horizontal irradiance (GHI) is proposed. This methodology is a combination of spatial modelling and artificial neural networks (ANNs) techniques. An ANN based model is developed to predict the local GHI based on daily weather forecasts provided by the US National Oceanic and Atmospheric Administration (NOAA) for four neighbouring locations. The methodology was tested for two locations; Le Bourget du Lac (45°38′44″N, 5°51′33″E), which is located in the French Alps and Cadarache (43°42′28″N, 05°46′31″E), which is located in the south of France. The model’s forecasts were compared to measured data for the two locations and validation results indicate that the ANN-based method presented in this study can estimate daily GHI with satisfactory accuracy

  15. LANL* V1.0: a radiation belt drift shell model suitable for real-time and reanalysis applications

    Energy Technology Data Exchange (ETDEWEB)

    Koller, Josep [Los Alamos National Laboratory; Reeves, Geoffrey D [Los Alamos National Laboratory; Friedel, Reiner H W [Los Alamos National Laboratory

    2008-01-01

    Space weather modeling, forecasts, and predictions, especially for the radiation belts in the inner magnetosphere, require detailed information about the Earth's magnetic field. Results depend on the magnetic field model and the L* (pron. L-star) values which are used to describe particle drift shells. Space wather models require integrating particle motions along trajectories that encircle the Earth. Numerical integration typically takes on the order of 10{sup 5} calls to a magnetic field model which makes the L* calculations very slow, in particular when using a dynamic and more accurate magnetic field model. Researchers currently tend to pick simplistic models over more accurate ones but also risking large inaccuracies and even wrong conclusions. For example, magnetic field models affect the calculation of electron phase space density by applying adiabatic invariants including the drift shell value L*. We present here a new method using a surrogate model based on a neural network technique to replace the time consuming L* calculations made with modern magnetic field models. The advantage of surrogate models (or meta-models) is that they can compute the same output in a fraction of the time while adding only a marginal error. Our drift shell model LANL* (Los Alamos National Lab L-star) is based on L* calculation using the TSK03 model. The surrogate model has currently been tested and validated only for geosynchronous regions but the method is generally applicable to any satellite orbit. Computations with the new model are several million times faster compared to the standard integration method while adding less than 1% error. Currently, real-time applications for forecasting and even nowcasting inner magnetospheric space weather is limited partly due to the long computing time of accurate L* values. Without them, real-time applications are limited in accuracy. Reanalysis application of past conditions in the inner magnetosphere are used to understand

  16. LANL* V1.0: a radiation belt drift shell model suitable for real-time and reanalysis applications

    International Nuclear Information System (INIS)

    Space weather modeling, forecasts, and predictions, especially for the radiation belts in the inner magnetosphere, require detailed information about the Earth's magnetic field. Results depend on the magnetic field model and the L* (pron. L-star) values which are used to describe particle drift shells. Space wather models require integrating particle motions along trajectories that encircle the Earth. Numerical integration typically takes on the order of 105 calls to a magnetic field model which makes the L* calculations very slow, in particular when using a dynamic and more accurate magnetic field model. Researchers currently tend to pick simplistic models over more accurate ones but also risking large inaccuracies and even wrong conclusions. For example, magnetic field models affect the calculation of electron phase space density by applying adiabatic invariants including the drift shell value L*. We present here a new method using a surrogate model based on a neural network technique to replace the time consuming L* calculations made with modern magnetic field models. The advantage of surrogate models (or meta-models) is that they can compute the same output in a fraction of the time while adding only a marginal error. Our drift shell model LANL* (Los Alamos National Lab L-star) is based on L* calculation using the TSK03 model. The surrogate model has currently been tested and validated only for geosynchronous regions but the method is generally applicable to any satellite orbit. Computations with the new model are several million times faster compared to the standard integration method while adding less than 1% error. Currently, real-time applications for forecasting and even nowcasting inner magnetospheric space weather is limited partly due to the long computing time of accurate L* values. Without them, real-time applications are limited in accuracy. Reanalysis application of past conditions in the inner magnetosphere are used to understand physical processes

  17. Processes of radiation-induced defect formation in quartz. III. Artificial amethyst

    International Nuclear Information System (INIS)

    It is shown that during gamma irradiation of r-crystals of amethyst in the dose range 104-106 R there are processes of migration of electron-alkali ion pairs (e-, Me+) and e-, H+ from O- Me+ and O-H+ groups of structural defects to triply coordinate Si↑ ions near interstitial iron ions. These processes create the necessary conditions for occurrence in the dose range 3 x 105-107 R of processes of countermigration of Me+ and H+ ions. With irradiation of amethyst by doses of over 106 R, the formation of marked concentrations of broken Si-O bonds causes the processes of migration of pairs e-, Me+ from growth defects to these radiation traps. The proposed model of radiation-stimulated processes explains the kinetics of the change in the main parameters of the optical absorption spectra in the UV, visible, and IR regions, acoustic (f = 1 MHz) and dielectric (f = 1 kHz) losses of artificial amethyst under gamma irradiation

  18. Investigation of the solar UV/EUV heating effect on the Jovian radiation belt by GMRT-IRTF observation

    Science.gov (United States)

    Kita, H.; Misawa, H.; Bhardwaj, A.; Tsuchiya, F.; Tao, C.; Uno, T.; Kondo, T.; Morioka, A.

    2012-12-01

    Jupiter's synchrotron radiation (JSR) is the emission from relativistic electrons, and it is the most effective probe for remote sensing of Jupiter's radiation belt from the Earth. Recent intensive observations of JSR revealed short term variations of JSR with the time scale of days to weeks. Brice and McDonough (1973) proposed a scenario for the short term variations; i.e, the solar UV/EUV heating for Jupiter's upper atmosphere causes enhancement of total flux density. The purpose of this study is to investigate whether sufficient solar UV/EUV heating in Jupiter's upper atmosphere can actually causes variation in the JSR total flux and brightness distribution. Previous JSR observations using the Giant Metrewave Radio Telescope (GMRT) suggested important characteristics of short term variations; relatively low energy particles are accelerated by some acceleration processes which might be driven by solar UV/EUV heating and/or Jupiter's own magnetic activities. In order to evaluate the effect of solar UV/EUV heating on JSR variations, we made coordinated observations using the GMRT and NASA Infra-Red Telescope Facility (IRTF). By using IRTF, we can estimate the temperature of Jupiter's upper atmosphere from spectroscopic observation of H_3^+ infrared emission. Hence, we can evaluate the relationship between variations in Jupiter's upper atmosphere initiated by the solar UV/EUV heating and its linkage with the JSR. The GMRT observations were made during Nov. 6-17, 2011 at the frequency of 235/610MHz. The H_3^+ 3.953 micron line was observed using the IRTF during Nov. 7-12, 2011. During the observation period, the solar UV/EUV flux variations expected on Jupiter showed monotonic increase. A preliminary analysis of GMRT 610MHz band showed a radio flux variation similar to that in the solar UV/EUV. Radio images showed that the emission intensity increased at the outer region and the position of equatorial peak emission moved in the outward direction. If radial diffusion

  19. Layered Model for Radiation-Induced Chemical Evolution of Icy Surface Composition and Dynamics on Kuiper Belt and Oort Cloud Bodies

    Science.gov (United States)

    Cooper, John F.; Richardson, John D.

    2010-01-01

    The diversity of albedos and surface colors on observed Kuiper Belt and Inner Oort Cloud objects remains to be explained in terms of competition between primordial intrinsic versus exogenic drivers of surface and near-surface evolution. Earlier models have attempted without success to attribute this diversity to the relations between surface radiolysis from cosmic ray irradiation and gardening by meteoritic impacts. A more flexible approach considers the different depth-dependent radiation profiles produced by low-energy plasma, suprathermal, and maximally penetrating charged particles of the heliospheric and local interstellar radiation environment. Generally red objects of the dynamically cold (low inclination, circular orbit) Classical Kuiper Belt might be accounted for from erosive effects of plasma ions and reddening effects of high energy cosmic ray ions, while suprathermal keV-MeV ions could alternatively produce more color neutral surfaces. The deepest layer of more pristine ice can be brought to the surface from meter to kilometer depths by larger impact events and potentially by cryovolcanic activity. The bright surfaces of some larger objects, e.g. Eris, suggest ongoing resurfacing activity. Cycles of atmospheric formation and surface freezeout can further account for temporal variation as observed on Pluto. The diversity of causative processes must therefore be understood to account for observationally apparent diversities of the object surfaces.

  20. Long-term observations of keV ion and electron variability in the outer radiation belt from CRRES

    International Nuclear Information System (INIS)

    The distribution of energetic electrons and ions with L-value (LST. These enhancements decay over less than 30 days. There is evidence of a magnetospheric electron and ion acceleration mechanism of considerable strength and efficiency. Very intense periods of activity can lead to the creation of an additional, high-energy belt in the slot region, which persists over a a period of many months. 11 refs., 1 fig

  1. Changes in the width of the tropical belt due to simple radiative forcing changes in the GeoMIP simulations

    Science.gov (United States)

    Davis, Nicholas A.; Seidel, Dian J.; Birner, Thomas; Davis, Sean M.; Tilmes, Simone

    2016-08-01

    Model simulations of future climates predict a poleward expansion of subtropical arid climates at the edges of Earth's tropical belt, which would have significant environmental and societal impacts. This expansion may be related to the poleward shift of the Hadley cell edges, where subsidence stabilizes the atmosphere and suppresses precipitation. Understanding the primary drivers of tropical expansion is hampered by the myriad forcing agents in most model projections of future climate. While many previous studies have examined the response of idealized models to simplified climate forcings and the response of comprehensive climate models to more complex climate forcings, few have examined how comprehensive climate models respond to simplified climate forcings. To shed light on robust processes associated with tropical expansion, here we examine how the tropical belt width, as measured by the Hadley cell edges, responds to simplified forcings in the Geoengineering Model Intercomparison Project (GeoMIP). The tropical belt expands in response to a quadrupling of atmospheric carbon dioxide concentrations and contracts in response to a reduction in the solar constant, with a range of a factor of 3 in the response among nine models. Models with more surface warming and an overall stronger temperature response to quadrupled carbon dioxide exhibit greater tropical expansion, a robust result in spite of inter-model differences in the mean Hadley cell width, parameterizations, and numerical schemes. Under a scenario where the solar constant is reduced to offset an instantaneous quadrupling of carbon dioxide, the Hadley cells remain at their preindustrial width, despite the residual stratospheric cooling associated with elevated carbon dioxide levels. Quadrupled carbon dioxide produces greater tropical belt expansion in the Southern Hemisphere than in the Northern Hemisphere. This expansion is strongest in austral summer and autumn. Ozone depletion has been argued to cause

  2. Antioxidant responses of damiana (Turnera diffusa Willd to exposure to artificial ultraviolet (UV radiation in an in vitro model: part II; UV-B radiation

    Directory of Open Access Journals (Sweden)

    Lluvia de Abril Alexandra Soriano-Melgar

    2014-05-01

    Full Text Available Introduction: Ultraviolet type B (UV-B radiation effects on medicinal plants have been recently investigated in the context of climate change, but the modifications generated by UV-B radiation might be used to increase the content of antioxidants, including phenolic compounds. Objective: To generate information on the effect of exposure to artificial UV-B radiation at different high-doses in the antioxidant content of damiana plants in an in vitro model. Methods: Damiana plantlets (tissue cultures in Murashige-Skoog medium were irradiated with artificial UV-B at 3 different doses (1 0.5 ± 0.1 mW cm-2 (high for 2 h daily, (2 1 ± 0,1 mW cm-2 (severe for 2 h daily, or (3 1 ± 0.1 mW cm-2 for 4 h daily during 3 weeks. The concentration of photosynthetic pigments (chlorophylls a and b, carotenoids, vitamins (C and E and total phenolic compounds, the enzymatic activity of superoxide dismutase (SOD, EC 1.15.1.1 and total peroxidases (POX, EC 1.11.1, as well as total antioxidant capacity and lipid peroxidation levels were quantified to assess the effect of high artificial UV-B radiation in the antioxidant content of in vitro damiana plants. Results: Severe and high doses of artificial UV-B radiation modified the antioxidant content by increasing the content of vitamin C and decreased the phenolic compound content, as well as modified the oxidative damage of damiana plants in an in vitro model. Conclusion: UV-B radiation modified the antioxidant content in damiana plants in an in vitro model, depending on the intensity and duration of the exposure.

  3. Radiometric mapping of Goiania urban area: natural and artificial radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Nivaldo C.; Dias, Danila C.S.; Guerrero, Eder T. Z.; Alberti, Heber L.C., E-mail: ncsilva@cnen.gov.br, E-mail: danilacdias@gmail.com, E-mail: edertzg@cnen.gov.br, E-mail: heber@cnen.gov.br [Comissao Nacional de Energia Nuclear (LAPOC/CNEN), Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas; Santos, Eliane E.; Pimenta, Lucinei R.; Costa, Heliana F., E-mail: esantos@cnen.gov.br, E-mail: lucinei@cnen.gov.br, E-mail: heliana@cnen.gov.br [Centro Regional de Ciencias Nucleares do Centro Oeste (CRCN-CO/CNEN-GO), Abadia de Goias, GO (Brazil)

    2013-07-01

    In the city of Goiania it is common to observe in some social groups, such as medical society, academy and communication (media), the association between cancer incidence and the 1987's Goiania radiological accident. Moreover, data of Population-Base Cancer Register published in 2010 by INCA (Instituto Nacional do Cancer), reveals that Goiania figures among the three cities where the major increases in cancer incidence were observed. Therefore, this project aims to provide a dose rate database over Goiania's road network aiming to: 1) assess the level radiation dose to which the population is exposed and 1) provide technical support for social communication of Brazilian Commission for Nuclear Energy. The monitoring was accomplished by using a mobile system (EBERLINE FHT 1376) which includes a 5-liter plastic scintillator detector coupled with a GPS (Global Positioning System) and a portable computer. This system allowed the recording of both the geographical coordinates and the dose rate of each single point. Using a NBR (Natural Background Rejection) the system is able to discriminate between natural and artificial radiation. After the field campaign, the raw data were then treated in a Geographical Information System (GIS) using the ArcGis software in order to produce dose maps. Therefore, this paper will present the results of the current stage of this research encompassing the monitoring of streets located on seven regions Goiania - divided in for administrative purposes. It is important to point out that more than 175175 individual data were collected with results ranging from 13 to 490 nSv/h. (author)

  4. Radiometric mapping of Goiania urban area: natural and artificial radiation dose

    International Nuclear Information System (INIS)

    In the city of Goiania it is common to observe in some social groups, such as medical society, academy and communication (media), the association between cancer incidence and the 1987's Goiania radiological accident. Moreover, data of Population-Base Cancer Register published in 2010 by INCA (Instituto Nacional do Cancer), reveals that Goiania figures among the three cities where the major increases in cancer incidence were observed. Therefore, this project aims to provide a dose rate database over Goiania's road network aiming to: 1) assess the level radiation dose to which the population is exposed and 1) provide technical support for social communication of Brazilian Commission for Nuclear Energy. The monitoring was accomplished by using a mobile system (EBERLINE FHT 1376) which includes a 5-liter plastic scintillator detector coupled with a GPS (Global Positioning System) and a portable computer. This system allowed the recording of both the geographical coordinates and the dose rate of each single point. Using a NBR (Natural Background Rejection) the system is able to discriminate between natural and artificial radiation. After the field campaign, the raw data were then treated in a Geographical Information System (GIS) using the ArcGis software in order to produce dose maps. Therefore, this paper will present the results of the current stage of this research encompassing the monitoring of streets located on seven regions Goiania - divided in for administrative purposes. It is important to point out that more than 175175 individual data were collected with results ranging from 13 to 490 nSv/h. (author)

  5. Optimization of an artificial neural network dedicated to the multivariate forecasting of daily global radiation

    International Nuclear Information System (INIS)

    This paper presents an application of Artificial Neural Networks (ANNs) to predict daily solar radiation. We look at the Multi-Layer Perceptron (MLP) network which is the most used of ANNs architectures. In previous studies, we have developed an ad-hoc time series preprocessing and optimized a MLP with endogenous inputs in order to forecast the solar radiation on a horizontal surface. We propose in this paper to study the contribution of exogenous meteorological data (multivariate method) as time series to our optimized MLP and compare with different forecasting methods: a naive forecaster (persistence), ARIMA reference predictor, an ANN with preprocessing using only endogenous inputs (univariate method) and an ANN with preprocessing using endogenous and exogenous inputs. The use of exogenous data generates an nRMSE decrease between 0.5% and 1% for two stations during 2006 and 2007 (Corsica Island, France). The prediction results are also relevant for the concrete case of a tilted PV wall (1.175 kWp). The addition of endogenous and exogenous data allows a 1% decrease of the nRMSE over a 6 months-cloudy period for the power production. While the use of exogenous data shows an interest in winter, endogenous data as inputs on a preprocessed ANN seem sufficient in summer. -- Research highlights: → Use of exogenous data as ANN inputs to forecast horizontal daily global irradiation data. → New methodology allowing to choice the adequate exogenous data - a systematic method comparing endogenous and exogenous data. → Different referenced mathematical predictors allows to conclude about the pertinence of the proposed methodology.

  6. Real time determination of dose radiation through artificial intelligence and virtual reality; Determinacao de dose de radiacao, em tempo real, atraves de inteligencia artificial e realidade virtual

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Victor Goncalves Gloria

    2009-07-01

    In the last years, a virtual environment of Argonauta research reactor, sited in the Instituto de Engenharia Nuclear (Brazil), has been developed. Such environment, called here Argonauta Virtual (AV), is a 3D model of the reactor hall, in which virtual people (avatar) can navigate. In AV, simulations of nuclear sources and doses are possible. In a recent work, a real time monitoring system (RTMS) was developed to provide (by means of Ethernet TCP/I P) the information of area detectors situated in the reactor hall. Extending the scope of AV, this work is intended to provide a continuous determination of gamma radiation dose in the reactor hall, based in several monitored parameters. To accomplish that a module based in artificial neural network (ANN) was developed. The ANN module is able to predict gamma radiation doses using as inputs: the avatar position (from virtual environment), the reactor power (from RTMS) and information of fixed area detectors (from RTMS). The ANN training data has been obtained by measurements of gamma radiation doses in a mesh of points, with previously defined positions, for different power levels. Through the use of ANN it is possible to estimate, in real time, the dose received by a person at any position in Argonauta reactor hall. Such approach allows tasks simulations and training of people inside the AV system, without exposing them to radiation effects. (author)

  7. Predicting Global Solar Radiation Using an Artificial Neural Network Single-Parameter Model

    Directory of Open Access Journals (Sweden)

    Karoro Angela

    2011-01-01

    Full Text Available We used five years of global solar radiation data to estimate the monthly average of daily global solar irradiation on a horizontal surface based on a single parameter, sunshine hours, using the artificial neural network method. The station under the study is located in Kampala, Uganda at a latitude of 0.19°N, a longitude of 32.34°E, and an altitude of 1200 m above sea level. The five-year data was split into two parts in 2003–2006 and 2007-2008; the first part was used for training, and the latter was used for testing the neural network. Amongst the models tested, the feed-forward back-propagation network with one hidden layer (65 neurons and with the tangent sigmoid as the transfer function emerged as the more appropriate model. Results obtained using the proposed model showed good agreement between the estimated and actual values of global solar irradiation. A correlation coefficient of 0.963 was obtained with a mean bias error of 0.055 MJ/m2 and a root mean square error of 0.521 MJ/m2. The single-parameter ANN model shows promise for estimating global solar irradiation at places where monitoring stations are not established and stations where we have one common parameter (sunshine hours.

  8. Research of radiation pressure and Poynting–Robertson effect influence on geodesic artificial satellites and space debris motion.

    OpenAIRE

    Nikolay A. Sorokin; Elena N. Kablova

    2013-01-01

    During space colonization it will be inevitably precision navigation using, that requires non-gravitational effects precise accounting. One of these effects mathematical description - radiation pressure with concomitant Poynting–Robertson effect influence on space objects as artificial satellites and space debris - is examined in this article. Satellite motion is accompanied by the Sun illuminance, with short-time operations in the Earth penumbra and umbra, that influence satellites orbit e...

  9. Study of energetic electrons in the outer radiation-belt regions using data obtained by the LLL spectrometer on OGO-5 in 1968

    International Nuclear Information System (INIS)

    An account is given of measurements of electrons made by the LLL magnetic electron spectrometer (60 to 3000 keV in seven differential energy channels) on the Ogo-5 satellite in the earth's outer-belt regions during 1968 and early 1969. The data were analyzed specifically to determine pitch-angle diffusion lifetimes as a function of energy in the L-range 2 to 5. As a part of this effort, the general dynamics of these regions were studied in terms of the time-dependent energy spectra, and pitch-angle distributions for the seven energy groups were obtained as a function of L with representative values presented for L = 2.5 to 6. The pitch-angle-diffusion results were used to analyze the dynamics of the electrons injected following the intense storms on October 31 and November 1, 1968, in terms of radial diffusion; the derived diffusion coefficients provide a quite reasonable picture of electron transport in the radiation belts. Both the radial- and pitch-angle-diffusion results are compared with earlier results. 53 references

  10. Survival rate of various species of dark-colored mushrooms under the influence of artificial solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhdanova, N.N.; Liulichev, A.N.; Vasilevskaia, A.I.; Antonenko, A.L.

    1978-01-01

    The resistance of several species of melanin-containing mushrooms to artificial solar radiation is investigated in light of their demonstrated resistance to UV radiation prevalent in the space environment. Specimens of the UV-resistant mushrooms Stemphylium ilicis, S. sarciniforme and Cladosporium transchelii and certain of its mutations with defects in melaninogenesis were irradiated by a simulated solar radiation with 10-12% of its energy in the UV at levels of up to 700 J/sq m sec in air and 1400 J/sq m sec in vacuum. Results obtained in air are found to be similar to those in vacuum, and indicate that resistance to damage induced by solar radiation is dependent on melanin content in the cellular envelope of the mushrooms studied.

  11. Great Belt

    DEFF Research Database (Denmark)

    Sørensen, Carsten S.; Kristensen, Per S.; Erichsen, Lars

    This paper describes aspects of the soil investigations and geotechnical evaluations for the foundation design of the 6.6 km long Great Belt West Bridge. The gravity foundations rest predominantly on glacial tills and pre-quaternary limestone. Special investigations for assessment of the soil pro...... properties for ship impact and ice loading are described briefly, and first experiences from settlement monitoring of the structure during erection are presented....

  12. MEASURING THE IMPACTS OF EXISTING ARTIFICIAL OPTICAL RADIATION AT 3 SITES: A PILOT STUDY OF MILITARY, STUDENT, AND OLDER ADULT HOUSING COMMUNITIES

    Science.gov (United States)

    By measuring and disseminating the impacts of existing artificial optical radiation and by comparing findings to current recommendations, future sustainable lighting choices for housing of military personnel, university students, and older adults will be enabled.

  13. Artificial diamonds as radiation-hard detectors for ultra-fast fission-fragment timing

    International Nuclear Information System (INIS)

    In the framework of the construction of the double time-of-flight spectrometer VERDI, where we aim at measuring pre- and post-neutron masses directly and simultaneously, ultra-fast time pick-up detectors based on artificial diamond material were investigated for the first time with fission fragments from 252Cf (0.5MeV/u9 fission-fragments/cm2 together with more than 3.5×109 neutrons/cm2 and 3×1010α-particles/cm2. This fluence is characteristic for fission experiments. The pre-requisite for the observed signal stability is the application of priming of the diamond material with a strong β-source for about 48 h. The intrinsic timing resolution of a 100μm thick polycrystalline CVD diamond detector with a size of 1×1 cm2 was determined to σint=(283±41)ps by comparison with Monte-Carlo simulations. Using broadband pre-amplifiers, 4-fold segmented detectors of same total size and with a thickness of 180μm show an intrinsic timing resolution of σint=(106±21)ps. This is highly competitive with the best micro-channel plate detectors. Due to the limited and batch-dependent charge collection efficiency of poly-crystalline diamond material, the detection efficiency for fission fragments may be smaller than 100%. -- Highlights: ► First use of chemical vapor deposited diamond for heavy ions with kinetic energies below 2 MeV per nucleon. ► Fission-fragment time-of-flight measurements with a timing resolution better than 150 ps. ► Radiation-hard fission event trigger to be used in an intense neutron field

  14. Multi-point observations of energetic particle injection deep into the inner magnetosphere: Implications for the ring current and radiation belts

    Science.gov (United States)

    Reeves, G. D.; Larsen, B.; Friedel, R. H. W.; Henderson, M. G.; Skoug, R. M.; Funsten, H. O.; Claudepierre, S. G.; Fennell, J.; Tu, W.; Cunningham, G.; Spence, H. E.

    2014-12-01

    For thirty years, the "injection boundary" model of substorm injections has provided a framework for studies of the impulsive transport of energetic electrons and ions into the inner magnetosphere. New, multi-satellite observations of substorm injections show signatures that require revision and rethinking of the classical picture. Recent observations by the LANL-GEO and GOES energetic particle instruments provide unprecedented coverage at geosynchronous orbit while the Van Allen Probes satellites provide simultaneous multi-point measurements inside geosynchronous orbit. With these satellites we can observe injections at three different radial distances and up to ten different local times - simultaneously. These observations reveal a complex and varied set of dynamics that have important implications for the development of the radiation belts and ring current. In this study we look specifically at the radial penetration of energetic particle injections in storms and substorms. Radial alignments of satellites confirm and extend the CRRES/LANL-GEO observations of relatively slow inward propagation of the injection region inside geosynchronous orbit [1]. At the same time, synoptic Van Allen Probes observations show frequent storm-time "injection" of energetic (~50-500 keV) electrons to very low L-shells (L storms and substorms have profound implications for the generation of waves, for the availability of a radiation belt "seed population", and for the radial distribution of ring current ions. In this paper we will use multi-point satellite observations to understand the processes that inject energetic particles into the inner magnetosphere, the Earthward propagation of these injections, the conditions that control variation in Earthward extent of energetic particle injections, and how particles can be injected deep inside the plasmasphere and even through the slot region. [1] Reeves, G. D., R. W. H. Friedel, M. G. Henderson, A. Korth, P. S. McLachlan, and R. D

  15. Study - Radiation Shielding Effectiveness of the Prototyped High Temperature Superconductivity (HTS) 'Artificial' Magnetosphere for Deep Space Missions

    Science.gov (United States)

    Denkins, Pamela

    2010-01-01

    The high temperature superconductor (HTS) is being used to develop the magnets for the Variable Specific Impulse Magneto-plasma Rocket (VASIMR ) propulsion system and may provide lightweight magnetic radiation shielding to protect spacecraft crews from radiation caused by GCR and SPEs on missions to Mars. A study is being planned to assess the radiation shielding effectiveness of the artificial magnetosphere produced by the HTS magnet. VASIMR is an advanced technology propulsion engine which is being touted as enabling one way transit to Mars in 90 days or less. This is extremely important to NASA. This technology would enable a significant reduction in the number of days in transit to and from Mars and significantly reduce the astronauts exposure to a major threat - high energy particles from solar storms and GCR during long term deep space missions. This paper summarizes the plans for the study and the subsequent testing of the VASIMR technology onboard the ISS slated for 2013.

  16. A comparison of the radio data and model calculations of Jupiter's synchrotron radiation. I - The high energy electron distribution in Jupiter's inner magnetosphere. II - East-west asymmetry in the radiation belts as a function of Jovian longitude

    Science.gov (United States)

    De Pater, I.

    1981-01-01

    A comparison has been made between detailed model calculations of Jupiter's synchrotron radiation and the radio data at wavelengths of 6, 21, and 50 cm. The calculations were performed for a Jovian longitude of 200 deg and were based on the multipole field configurations as derived from the Pioneer data. The electron distribution in the inner magnetosphere was derived as a function of energy, pitch angle, and spatial coordinates. In addition, the hot region or east-west asymmetry in the radiation belts is investigated. It is suggested that this asymmetry is due to the combined effect of an overabundance of electrons at jovicentric longitudes of 240-360 deg and the existence of a dusk-to-dawn directed electric field over the inner magnetosphere generated by the wind system in the upper atmosphere.

  17. Select the most relevant input parameters using WEKA for models forecast Solar radiation based on Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Somaieh Ayalvary

    2015-11-01

    Full Text Available Forecasting solar radiation is important for many applications in research related to renewable energy. Solar radiation is forecasted by solar radiation forecast models including the traditional models and artificial neural network (ANN based model. There are geographical and meteorological variables that affect the solar radiation, thus identifying the appropriate variables to forecast solar radiation correctly is an important issue in the research area. Accordingly Waikato Environment for Knowledge Analysis (WEKA Software was used in 11 points in Guilan based on different weather conditions to find the most effective input parameters to forecast solar radiation in different ANN models. Input parameters include latitude, longitude, maximum wind speed, average temperatures in each month, the average maximum air temperature, average minimum air temperature, sunshine, monthly rainfall, maximum rainfall in a day  for different cities of Gilan. In order to check the reliability of the forecasts by known parameters, three ANN models have developed (ANN-1, ANN-2 and ANN-3. The maximum MAPE for ANN-1, ANN-2 and ANN-3 equals 22.15%, 20.29% and 22.14%, respectively indicating 1.86% improvement in the accuracy in the prediction of ANN-2. 

  18. A hopfield-like artificial neural network for solving inverse radiation transport problems

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hoon

    1997-02-15

    In this thesis, we solve inverse radiation transport problems by an Artificial Neural Network(ANN) approach. ANNs have many interesting properties such as nonlinear, parallel, and distributed processing. Some of the promising applications of ANNs are optimization, image and signal processing, system control, etc. In some optimization problems, Hopfield Neural Network(HNN) which has one-layered and fully interconnected neurons with feed-back topology showed that it worked well with acceptable fault tolerance and efficiency. The identification of radioactive source in a medium with a limited number of external detectors is treated as an inverse radiation transport problem in this work. This kind of inverse problem is usually ill-posed and severely under-determined; however, its applications are very useful in many fields including medical diagnosis and nondestructive assay of nuclear materials. Therefore, it is desired to develop efficient and robust solution algorithms. Firstly, we study a representative ANN model which has learning ability and fault tolerance, i.e., feed-forward neural network. It has an error backpropagation learning algorithm processed by reducing error in learning patterns that are usually results of test or calculation. Although it has enough fault tolerance and efficiency, a major obstacle is 'curse of dimensionality'--required number of learning patterns and learning time increase exponentially proportional to the problem size. Therefore, in this thesis, this type of ANN is used as benchmarking the reliability of the solution. Secondly, another approach for solving inverse problems, a modified version of HNN is proposed. When diagonal elements of the interconnection matrix are not zero, HNN may become unstable. However, most problems including this identification problem contain non-zero diagonal elements when programmed on neural networks. According to Soulie et al., discrete random iterations could produce the stable minimum state

  19. A hopfield-like artificial neural network for solving inverse radiation transport problems

    International Nuclear Information System (INIS)

    In this thesis, we solve inverse radiation transport problems by an Artificial Neural Network(ANN) approach. ANNs have many interesting properties such as nonlinear, parallel, and distributed processing. Some of the promising applications of ANNs are optimization, image and signal processing, system control, etc. In some optimization problems, Hopfield Neural Network(HNN) which has one-layered and fully interconnected neurons with feed-back topology showed that it worked well with acceptable fault tolerance and efficiency. The identification of radioactive source in a medium with a limited number of external detectors is treated as an inverse radiation transport problem in this work. This kind of inverse problem is usually ill-posed and severely under-determined; however, its applications are very useful in many fields including medical diagnosis and nondestructive assay of nuclear materials. Therefore, it is desired to develop efficient and robust solution algorithms. Firstly, we study a representative ANN model which has learning ability and fault tolerance, i.e., feed-forward neural network. It has an error backpropagation learning algorithm processed by reducing error in learning patterns that are usually results of test or calculation. Although it has enough fault tolerance and efficiency, a major obstacle is 'curse of dimensionality'--required number of learning patterns and learning time increase exponentially proportional to the problem size. Therefore, in this thesis, this type of ANN is used as benchmarking the reliability of the solution. Secondly, another approach for solving inverse problems, a modified version of HNN is proposed. When diagonal elements of the interconnection matrix are not zero, HNN may become unstable. However, most problems including this identification problem contain non-zero diagonal elements when programmed on neural networks. According to Soulie et al., discrete random iterations could produce the stable minimum state

  20. Monitoring of the outer radiation belt with GLONASS - the mid-altitude earth-symmetric multi-satellite constellation: experience and findings

    Science.gov (United States)

    Pavlov, Nikolai; Tulupov, Vladimir

    The project consists in the use of several satellites from the 24-birds GLONASS constellation for routine radiation monitoring in the orbit. Rather simple and almost identical particle sensors are used. Lowest reachable L is 4; presented period - 6.5 recent years. Time profiles with pure relativistic-electron component and solar protons are shown and identified. Very low fluxes of all types were observed in 2009. Besides 2009, only slight-to-moderate deviations from the model AE8 we saw in the entire period. Remarkable precision of the satellite positioning in orbit and symmetry of the orbit allow us easily keep watch of the (a)symmetry of the outer radiation belt and thereby, maybe, of this property of geomagnetic field; quasi-static spatial and sometimes even temporal variations are shown and discussed. Also we compare our data with those from GOES, RBSP/VAP and with the field models. High-intensity electron fluxes were found on the declining phase of the solar-activity cycle; similar GOES data are known to have a wide peak at the same phase too. We analyze the situation and investigate if GLONASS electrons behave like the GOES ones or they tend to shift their peak closer to the sunspot numbers' one. General pros and cons of the use of the GLONASS orbit/constellation for the magnetospheric research/monitoring are discussed.

  1. Hourly photosynthetically active radiation estimation in Midwestern United States from artificial neural networks and conventional regressions models

    Science.gov (United States)

    Yu, Xiaolei; Guo, Xulin

    2016-08-01

    The relationship between hourly photosynthetically active radiation (PAR) and the global solar radiation ( R s ) was analyzed from data gathered over 3 years at Bondville, IL, and Sioux Falls, SD, Midwestern USA. These data were used to determine temporal variability of the PAR fraction and its dependence on different sky conditions, which were defined by the clearness index. Meanwhile, models based on artificial neural networks (ANNs) were established for predicting hourly PAR. The performance of the proposed models was compared with four existing conventional regression models in terms of the normalized root mean square error (NRMSE), the coefficient of determination ( r 2), the mean percentage error (MPE), and the relative standard error (RSE). From the overall analysis, it shows that the ANN model can predict PAR accurately, especially for overcast sky and clear sky conditions. Meanwhile, the parameters related to water vapor do not improve the prediction result significantly.

  2. Generation of synthetic daily global solar radiation data based on ERA-Interim reanalysis and artificial neural networks

    International Nuclear Information System (INIS)

    Four variables (total cloud cover, skin temperature, total column water vapour and total column ozone) from meteorological reanalysis were used to generate synthetic daily global solar radiation via artificial neural network (ANN) techniques. The goal of our study was to predict solar radiation values in locations without ground measurements, by using the reanalysis data as an alternative to the use of satellite imagery. The model was validated in Andalusia (Spain), using measured data for nine years from 83 ground stations spread over the region. The geographical location (latitude, longitude), the day of the year, the daily clear sky global radiation, and the four meteorological variables were used as input data, while the daily global solar radiation was the only output of the ANN. Sixty five ground stations were used as training dataset and eighteen stations as independent dataset. The optimum network architecture yielded a root mean square error of 16.4% and a correlation coefficient of 94% for the testing stations. Furthermore, we have successfully tested the forecasting capability of the model with measured radiation values at a later time. These results demonstrate the generalization capability of this approach over unseen data and its ability to produce accurate estimates and forecasts. -- Highlights: → Accuracy synthetic daily global solar radiation data were generated using neural networks techniques. → Meteorological variables from ERA-Interim reanalysis were used as input variables. → Data from 83 stations for 10 years were used, and daily global radiation maps were generated. → The method could be used as a good alternative to the use of satellite imagery. → Furthermore, the forecasting capability of the model was successfully probed.

  3. Characteristics of flux-time profiles, temporal evolution, and spatial distribution of radiation-belt electron precipitation bursts in the upper ionosphere before great and giant earthquakes

    Directory of Open Access Journals (Sweden)

    Sergey Pulinets

    2012-04-01

    Full Text Available

    The analysis of energetic electron observations made by the DEMETER satellite reveals that radiation belt electron precipitation (RBEP bursts are observed in general several (~1-6 days before a large (M > 6.5 earthquake (EQ in the presence of broad band (~1-20 kHz VLF waves. The EBs show in general a relative peak-to-background flux increase usually < 100, they have a time duration of ~0.5 – 3 min, and their energy spectrum reach up to energies <~500 keV. The RBEP activity is observed as one, two or three EBs throughout a semi-orbit, depended on the magnetic field structure above the EQ epicenter. A statistical analysis has been made for earthquakes in Japan, which reveals a standard temporal variation of the number of EBs, which begins with an incremental rate several days before major earthquakes, and after a maximum, decreases so that the electron precipitation ceases above the epicenter. Some earthquake induced EBs were observed not only in the nightside ionosphere, but also in the dayside ionosphere.

     

  4. Comparison of radio data and model calculations of Jupiter's synchrotron radition 2. East--west asymmetry in the radiation belts as a functon of Jovian longitude

    International Nuclear Information System (INIS)

    On the basis of comparison of radio data and model calculations of Jupiter's synchrotron radiaton the 'hot region' or east--west asymmetry in the planet's radiation belts is proposed to be due to the combined effect of an overabundance of electrons at jovicentric longitudes lambda/sub J/approx.240 0--360 0 and the existence of a dusk dawn directed electric field over the inner magnetosphere, generated by the wind system in the upper atmosphere. The model calculations were based upon the magnetic field configurations derived from the Pioneer data by Acuna and Ness [1976] (the O4 model) and Davis, Jones and Smith (quoted in Smith and Gulkis [1979]) (the P11 (3,2)A model), with an electron distribution derived in the first paper of this series [de Pater, this issue]. We would infer from the calculations that the O4 model gives a slightly better fit to the data; the relatively large number density at lambda/sub J/approx.240 0--360 0, however, might indicate the presence of even higher order moments in the field

  5. Average profiles of the solar wind and outer radiation belt during the extreme flux enhancement of relativistic electrons at geosynchronous orbit

    Directory of Open Access Journals (Sweden)

    R. Kataoka

    2008-06-01

    Full Text Available We report average profiles of the solar wind and outer radiation belt during the extreme flux enhancement of relativistic electrons at geosynchronous orbit (GEO. It is found that seven of top ten extreme events at GEO during solar cycle 23 are associated with the magnetosphere inflation during the storm recovery phase as caused by the large-scale solar wind structure of very low dynamic pressure (<1.0 nPa during rapid speed decrease from very high (>650 km/s to typical (400–500 km/s in a few days. For the seven events, the solar wind parameters, geomagnetic activity indices, and relativistic electron flux and geomagnetic field at GEO are superposed at the local noon period of GOES satellites to investigate the physical cause. The average profiles support the "double inflation" mechanism that the rarefaction of the solar wind and subsequent magnetosphere inflation are one of the best conditions to produce the extreme flux enhancement at GEO because of the excellent magnetic confinement of relativistic electrons by reducing the drift loss of trapped electrons at dayside magnetopause.

  6. Energy ranges and pitch angles of outer radiation belt electrons depleted by an intense dayside hydrogen band EMIC wave event on February 23, 2014

    Science.gov (United States)

    Engebretson, M. J.; Posch, J. L.; Huang, C. L.; Kanekal, S. G.; Fok, M. C. H.; Rodger, C. J.; Smith, C. W.; Spence, H. E.; Baker, D. N.; Kletzing, C.; Wygant, J. R.

    2015-12-01

    Although most studies of the effect of EMIC waves on relativistic electrons have focused on wave events in the afternoon sector in the outer plasmasphere or plume region, strong magnetospheric compressions provide an additional stimulus for EMIC wave generation across a large range of local times and L shells. We present here observations of the effects of an intense, long-duration hydrogen band EMIC wave event on February 23, 2014 that was stimulated by a gradual 4-hour rise and subsequent sharp increases in solar wind pressure. Large-amplitude linearly polarized hydrogen band EMIC waves (up to 25 nT p-p) that included triggered emissions appeared for over 4 hours at both Van Allen Probes while these spacecraft were outside the plasmapause, in a region with densities ~5-20 cm-3, as they passed near apogee from late morning through local noon. Observations of radiation belt electrons by the REPT and MagEIS instruments on these spacecraft showed that these waves caused significant depletions of more field-aligned electrons at ultrarelativistic energies from 5.2 MeV down to ~2 MeV, and some depletions at energies down to below 1 MeV as well.

  7. Belt attachment and system

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Abraham D.; Davidson, Erick M.

    2016-02-02

    Disclosed herein is a belt assembly including a flexible belt with an improved belt attachment. The belt attachment includes two crossbars spaced along the length of the belt. The crossbars retain bearings that allow predetermined movement in six degrees of freedom. The crossbars are connected by a rigid body that attaches to the bearings. Implements that are attached to the rigid body are simply supported but restrained in pitching rotation.

  8. Antioxidant responses of damiana (Turnera diffusa Willd to exposure to artificial ultraviolet (UV radiation in an in vitro model: part I; UV-C radiation

    Directory of Open Access Journals (Sweden)

    Lluvia de Abril Alexandra Soriano-Melgar

    2014-05-01

    Full Text Available Introduction: Ultraviolet type C (UV-C radiation has higher energy than the UV-B radiation and has been less studied because it is completely absorbed by the ozone layer. However, artificial UV-C radiation can generate diverse modifications in the plants. Given that exposure to UV-C for short periods of time increases the antioxidant content, improving the appearance and shelf-life of products, its potential application in postharvest treatments to modify the antioxidant content of medicinal plants, such as damiana (Turnera diffusa, is novel and relevant. Objective: To determine the effects of UV-C radiation on enzymatic and non-enzymatic antioxidant defenses, as well as oxidative damage levels, in damiana (Turnera diffusa plants in vitro. Results: UV-C radiation decreased superoxide dismutase (SOD, EC 1.15.1.1 and total peroxidases (POX, EC 1.11.1 activities, the concentration of chlorophylls (a and b, carotenes, vitamin C, and total antioxidant capacity. UV-C radiation increased the phenolic compound levels in damiana. Loss of antioxidant defenses was higher in damiana plants exposed to higher UV-C doses and/or for longer periods. This study suggests that UV-C radiation induces oxidative stress, evidenced as increased protein carbonyls and phenolic compound content, in damiana (T. diffusa. Conclusion: Low dose, short exposure to UV-C stimulates phenolic compound content in damiana. Thus, controlled UV-C treatments could be used as postharvest treatment to increase phenolic compound content in damiana plants.

  9. Gamma radiation effects on phases of evolutional cycle of Plodia interpunctella (Huebner, 1813) (Lepidoptera, Pyralidae) on artificial diet

    International Nuclear Information System (INIS)

    The effects of increased gamma radiation (60 Co) doses on different phases of the evolutional cycle of Plodia interpunctella (Hubner,1813) (Lepidoptera, Pyralidae) have bean studied under laboratory conditions in the Laboratory of Radioentomology of the Nuclear Energy for Agriculture Center (CENA) in Piracicaba, Sao Paulo State, Brazil. For all treatments with gamma radiation a Cobalt-60 source type Gamma bean-650 has been used and the activity was of approximately 2.93 x 1014 Bq (7,925 Ci), with a dose rate of 2.80 KGy per hour and the insects were kept in a climatic chamber with the temperature adjusted to 27 ± 20 C and a relative humidity of 70 ± 10%. The LD50 and LD100 of gamma radiation for eggs of in artificial diet were respectively 51 Gy and 125 Gy. The sterilizing doses in adults which were irradiated at immature phases (larvae and pupae) were 160 Gy and 250 Gy respectively. The sterilizing doses for adults females and males were respectively 250 Gy and 300 Gy. The LD100 for adult males was 4,750 Gy, 4,500 Gy for females and 4,750 Gy for insects at random. (author). 70 refs., 10 figs., 19 tabs

  10. Device for continuous tare measurement at belt weighers

    International Nuclear Information System (INIS)

    The described device can be used for belt weighers connected with a computing unit. Its development has been aimed at measuring the weight of the belt without standstill. This could be achieved by arranging radiation sources and detectors over the whole width of the belt and transforming the radiation attenuation into weight equivalents with the aid of an evaluation unit connected to the computing unit

  11. Effect of ionizing radiation on fresh vegetables artificially contaminated with Vibrio cholerae

    International Nuclear Information System (INIS)

    Lettuce, cabbage and celery were artificially contaminated with Vibrio cholerae El Tor 01 Inaba, and irradiated at 0.50, 0.75 and 1.00 kGy. Non-irradiated samples were used as controls. The effect of irradiation was measured during 7-days storage under refrigeration, from the viewpoints of microbiological (MPN), nutritional (Vitamin C content), and sensory quality. Irradiation proved to be an effective technique to eliminate V. cholerae in fresh vegetables. Doses of less than 0.75 kGy were sufficient to eliminate an initial contamination of 105 cells/g of V. cholerae; neither sensory properties or nutritional quality (Vitamin C content) were adversely affected by the treatment. The cost of irradiating the vegetables at 0.5 kGy under the conditions of the study was US$ 0.131, 0.067 and 0.445 per unit of lettuce, cabbage and celery, respectively. (author)

  12. Artificial semi-rigid tissue sensitized with natural pigments: Effect of photon radiations

    Directory of Open Access Journals (Sweden)

    Adnan Jaradat

    2011-01-01

    Full Text Available Background: A new approach for evaluating the optical penetration depth and testing its validity with Monte Carlo simulations and Kubelka-Munk theory is used for artificial semi-rigid tissue sensitized with natural pigments. Photodynamic therapy is a promising cancer treatment in which a photosensitizing drug concentrates in malignant cells and is activated by visible light at certain wavelength. Materials and Methods: Cheap artificial semi-rigid tissue incorporated with scattering and absorbing materials along with some other composites comparable to normal human tissue has been performed. The optical parameters as measured with different conditions and calculated with various techniques are investigated. Results: The probability of interaction of light with tissue is very high when exposed to light in presence of Cichorium pumilum and RBCs followed by photohemolysis or/and photodegradation. The optical penetration depth calculated by linear absorption coefficient ranges from 0.63 to 2.85 mm is found to be comparable to those calculated using Kubelka-Munk theory or Monte Carlo simulation (range from 0.78 to 2.42 mm. The ratio of absorption to the scattering is independent of thickness and decreases with increasing irradiation time. Moreover, the optical parameters as well as their ratios are in very good agreement in the two approaches of calculation. The values of absorption and scattering coefficients are independent of thickness. Furthermore, the average photon ranges in the samples containing no scattering and absorbing materials are about three times greater than those samples containing scattering materials. Conclusion: Our results suggest that light propagation with optical properties presented in this work could be applicable in diagnostic and therapeutic of the human biological tissue for photodynamic therapy.

  13. An artificial neural network based fast radiative transfer model for simulating infrared sounder radiances

    Indian Academy of Sciences (India)

    Praveen Krishnan; K Srinivasa Ramanujam; C Balaji

    2012-08-01

    The first step in developing any algorithm to retrieve the atmospheric temperature and humidity parameters at various pressure levels is the simulation of the top of the atmosphere radiances that can be measured by the satellite. This study reports the results of radiative transfer simulations for the multichannel infrared sounder of the proposed Indian satellite INSAT-3D due to be launched shortly. Here, the widely used community software k Compressed Atmospheric Radiative Transfer Algorithm (kCARTA) is employed for performing the radiative transfer simulations. Though well established and benchmarked, kCARTA is a line-by-line solver and hence takes enormous computational time and effort for simulating the multispectral radiances for a given atmospheric scene. This necessitates the development of a much faster and at the same time, equally accurate RT model that can drive a real-time retrieval algorithm. In the present study, a fast radiative transfer model using neural networks is proposed to simulate radiances corresponding to the wavenumbers of INSAT-3D. Realistic atmospheric temperature and humidity profiles have been used for training the network. Spectral response functions of GOES-13, a satellite similar in construction, purpose and design and already in use are used. The fast RT model is able to simulate the radiances for 1200 profiles in 18 ms for a 15-channel GOES profile, with a correlation coefficient of over 99%. Finally, the robustness of the model is tested using additional synthetic profiles generated using empirical orthogonal functions (EOF).

  14. Aplicação de radiação UV artificial e solar no tratamento fotocatalítico de efluentes de curtume Application of artificial and solar UV radiation in the photocatalytic treatment of a tannery effluent

    Directory of Open Access Journals (Sweden)

    Salomão de Andrade Pascoal

    2007-10-01

    Full Text Available Tannery effluents are very dangerous for the environment since they contain large amounts of dangerous and biorecalcitrant contaminants (organic matter and Cr(VI. This paper reports the efficiency of heterogeneous photocatalysis, based on the application of solar and artificial radiation, furnished by UV lamps, using TiO2 fixed on a flat plate, in the treatment of synthetic effluents. The results of COD and Cr(VI demonstrate that the use of solar radiation is the most efficient way to perform the photocatalytic treatment of these effluents since a minimum removal of 62 and 61% was observed for Cr(VI and organic matter, respectively.

  15. The design and implementation of a high sensitivity telescope for in situ measurements of energetic particles in the Earth's radiation belts

    Science.gov (United States)

    Parker, Charles Walter

    This work describes the design and implementation of a high-sensitivity telescope (HST) for in situ detection and energy analysis of energetic charged particles in the Earth's radiation belts from a near-equatorial orbit that will range over geocentric distances from ≈ 2--3.5 Earth radii as part of the US Air Force's Demonstrations and Science eXperiment (DSX) mission. The HST employs a two element silicon solid state detector telescope that has a geometrical factor of 0.1 cm2 sr with a 14° field-of-view centered on the on-orbit local magnetic field vector to detect ≈ 100 particles s-1 cm-2 sr-1 in the geomagnetic bounce loss cone. The pointing direction of the HST is guaranteed by the active attitude control subsystem of the spacecraft. A novel implementation of a knife-edged baffled collimator design restricts the field-of-view and provides a sharp cutoff (≈ 103) in the angular response to all particle species with energies from ≈ 40--800 keV. The HST detectors are shielded with 5g cm-2 of aluminum followed by 3.1 g cm-2 of tungsten in all non-look directions to reduce the background fluxes incident on the detectors through the orbit (>107 particles cm -2 s-1 for electrons and protons individually) to levels that will allow the detection of the target flux in the loss cone. The HST has been extensively characterized on the ground and is capable of analyzing the energies of particles over the range of 25--850 keV with an energy resolution of 3.7keV and a noise FWHM of 15keV. The calibration has been established using 241Am and 133Ba X-ray sources and verified using additional beta- and X-ray sources and the electron beams produced by the 2 MeV Van de Graaff accelerator at the NASA Goddard Spaceflight Center's Radiation Effects Facility. The instrument's calibration has been shown to vary by less than 2% over the operational temperature range of --20 to +35°C. Electromagnetic interference testing has proven that the HST is unaffected by strong VLF fields

  16. Growth and flowering of Eustoma grandiflorum as affected by artificial reduction of direct solar radiation

    International Nuclear Information System (INIS)

    In order to estimate the effect of topographic shading on growth and flowering of Eustoma grandiflorumin hilly and mountainous areas, 3 early-flowering cultivars and a late-flowering cultivar were planted close to artificial sheets (3.1 m high) facing east, west, south and north in November, June and September. Total photon flux density (TPFD) on the north side of the sheet was 21% of that on the south side during winter, whereas TPFD was 94% during summer. In the November planting, plants were exposed to low TPFD on the north side just after planting and flower quality of early-flowering cultivars on the north side was better than that on the south side. In the June planting, growth of Eustoma was similar in all plots. In the September planting, when TPFD decreased after planting, growth of Eustoma on the north side was reduced in comparison with that on the other three sides. On the east and west sides, all cultivars flowered normally irrespective of planting date, and the mean values of TPFD in December and January were larger than 10 μmol m-2 day-1. The results indicate that high quality flowers may be produced in hilly and mountainous areas where TPFD values of 10 mol m-2 day-1 are ensured. (author)

  17. Effects of environmental and artificial UV-B radiation on freshwater prawn Macrobrachium olfersi embryos

    Energy Technology Data Exchange (ETDEWEB)

    Nazari, Evelise Maria [Programa de Pos-Graduacao em Ciencias Morfologicas, Instituto de Ciencias Biomedicas, Universidade Federal do Rio de Janeiro, 21949-902 Rio de Janeiro, RJ (Brazil); Universidade Federal de Santa Catarina, Departamento de Biologia Celular, Embriologia e Genetica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Ammar, Dib [Universidade do Oeste de Santa Catarina, Departamento de Biologia, Campus Universitario, 89600-000 Joacaba, SC (Brazil); Bem, Andreza Fabro de; Latini, Alexandra [Universidade Federal de Santa Catarina, Departamento de Bioquimica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Mueller, Yara Maria Rauh [Universidade Federal de Santa Catarina, Departamento de Biologia Celular, Embriologia e Genetica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Allodi, Silvana, E-mail: sallodi@histo.ufrj.br [Programa de Pos-Graduacao em Ciencias Morfologicas, Instituto de Ciencias Biomedicas, Universidade Federal do Rio de Janeiro, 21949-902 Rio de Janeiro, RJ (Brazil)

    2010-06-01

    The recent decrease of the stratospheric ozone has resulted in an increase of ultraviolet-B (UV-B) radiation reaching the Earth's surface. In freshwater ecosystems with transparent water, UV-B rays easily penetrate and potentially cause harmful effects to organisms. In this study, embryos of the prawn Macrobrachium olfersi were used to evaluate the impact of UV-B rays in freshwater environments. We observed three groups of embryos: the first was to assess whether UV-B radiation produced morphological defects and/or biochemical impairments in the laboratory. The second was to check whether embryos with the same impairments as those observed in the laboratory were found in their environment, under natural solar radiation. The third group was the non-irradiated control. The embryos irradiated with 310 mW cm{sup -2} UV-B for 30 min showed morphological alterations similar to those observed in embryos from the environmental control group. The most important effects of the UV-B radiation observed in M. olfersi embryos were morphological (1.2% of the total number of embryos from the environment and 2.8% of the total number of irradiated embryos), pigmentation changes in the eyes (78.0% of the total number of embryos from the environment and 98.9% of the total number of irradiated embryos), and disruption of the chromatophores (46.9% of the total number of embryos from the environment and 95.5% of the total number of irradiated embryos). We also observed an increase in egg volume, which was accompanied by a significant increase in water content in UV-B irradiated groups when compared with aquaria control embryos. In addition, a significant decrease in the mitotic index in eggs exposed to UV-B radiation was detected (0.17 for the embryos from the aquaria control, 0.10 for the embryos of the environmental control, and 0.04 for the irradiated groups). The low levels of NPSH and high levels of TBARS indicated that UV-B rays directly compromised the antioxidant function of

  18. Adaptive radiation in the Hawaiian silversword alliance (Compositae-Madiinae). II. Cytogenetics of artificial and natural hybrids

    International Nuclear Information System (INIS)

    The Hawaiian silversword alliance of Argyroxiphium, Dubautia, and Wilkesia, in spite of exhibiting spectacular morphological, ecological, physiological, and chromosomal diversity, is remarkably cohesive, genetically. This is attested to by the ease of production of artificial hybrids and by the high frequency of spontaneous hybridization among such life forms as mat-forming subshrub, monocarpic rosette shrub, polycarpic shrub, cushion plant, tree, and vine. Even the least fertile of these hybrids is capable of producing backcross progeny. Moreover, first generation interspecific and intergeneric hybrids have been successfully used to produce trispecific hybrids in a number of instances. In general, the widest hybrid combinations have been as readily produced as crosses within a species. At present eight genomes or chromosome races distinguished by reciprocal translocations are recognized on the basis of meiotic analysis of artificial and spontaneous hybrids. Seven of these races are found among those species with 14 pairs of chromosomes. The eighth genome very likely characterizes all nine species of this alliance that have 13 pairs of chromosomes. The cytogenetic data indicate that redundancy of translocations involving the same chromosomes has been a recurrent theme in the chromosomal differentiation of these taxa. There appears to be little, if any, correlation between chromosomal evolution and adaptive radiation as assessed by gross habital differentiation in this group. However, within Dubautia, a novel ecophysiological trait associated with colonization of xeric habitats is restricted to species with n = 13. In contrast to the bulk of the Hawaiian flora, which is characterized by self-compatibility and chromosomal stability, it is suggested that the occurrence of self-incompatibility in the Hawaiian Madiinae may have favored selection of supergenes via chromosomal repatterning, and this may account for the diversity of chromosome structure seen in this group

  19. The dynamic radiation environment assimilation model (DREAM)

    International Nuclear Information System (INIS)

    The Dynamic Radiation Environment Assimilation Model (DREAM) is a 3-year effort sponsored by the US Department of Energy to provide global, retrospective, or real-time specification of the natural and potential nuclear radiation environments. The DREAM model uses Kalman filtering techniques that combine the strengths of new physical models of the radiation belts with electron observations from long-term satellite systems such as GPS and geosynchronous systems. DREAM includes a physics model for the production and long-term evolution of artificial radiation belts from high altitude nuclear explosions. DREAM has been validated against satellites in arbitrary orbits and consistently produces more accurate results than existing models. Tools for user-specific applications and graphical displays are in beta testing and a real-time version of DREAM has been in continuous operation since November 2009.

  20. The dynamic radiation environment assimilation model (DREAM)

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, Geoffrey D [Los Alamos National Laboratory; Koller, Josef [Los Alamos National Laboratory; Tokar, Robert L [Los Alamos National Laboratory; Chen, Yue [Los Alamos National Laboratory; Henderson, Michael G [Los Alamos National Laboratory; Friedel, Reiner H [Los Alamos National Laboratory

    2010-01-01

    The Dynamic Radiation Environment Assimilation Model (DREAM) is a 3-year effort sponsored by the US Department of Energy to provide global, retrospective, or real-time specification of the natural and potential nuclear radiation environments. The DREAM model uses Kalman filtering techniques that combine the strengths of new physical models of the radiation belts with electron observations from long-term satellite systems such as GPS and geosynchronous systems. DREAM includes a physics model for the production and long-term evolution of artificial radiation belts from high altitude nuclear explosions. DREAM has been validated against satellites in arbitrary orbits and consistently produces more accurate results than existing models. Tools for user-specific applications and graphical displays are in beta testing and a real-time version of DREAM has been in continuous operation since November 2009.

  1. Effects of gamma radiation and electron beam on samples of the Brazil nuts artificially inoculated with Aspergillus flavus

    International Nuclear Information System (INIS)

    The high level of contamination by aflatoxin produced by fungi in lots of Brazil nuts and the strict control by importing countries in relation to the levels of toxins in food, European Union countries decided in 2003 by the return of these lots products from Brazil. Despite the economic loss represented by contamination by toxigenic fungi in Brazil nuts, a major product of extractive Northern of Brazil, studies are still preliminary as the control of contamination aflatoxigenic fungal using methods such as gamma radiation (G.R) and mainly, electron beam (E.B). These facts motivated this research, which aimed to evaluate the effects of gamma radiation and application of electron beam in samples of Brazil nut artificially inoculated with Aspergillus flavus. This goal, we were studied 50 samples of the Brazil nut previously inoculated with spores of A. flavus and subsequently incubated at 30 °C in relative humidity controlled at 93%. After incubation, period of 15 days, the average water activity of the samples was 0.80, the samples were divided into 5 groups that received the following doses of radiation: control (0 kGy), 5 and 10 kGy 5 E.B and G.R. The mycobiota was performed by serial dilution, plated on surface using potato dextrose agar. The results demonstrated that treatment with E.B using a dose of 5 kGy and 10 kGy resulted in reduced growth of A. flavus in 74% (37/50) and 94% (47/50) of samples. The samples treated with G.R at the dose of 5 kGy and 10 kGy no fungal growth occurred in 92% (46/50) 100% (50/50) of. The study of aflatoxins showed that doses of E.B of 5 kGy and 10 kGy reduced levels of AFB1 at 53.32% and 65.66% respectively. The application of gamma rays at doses of 5 and 10 kGy reduced levels of toxins in 70.61% and 84.15% respectively. This result may be attributed to higher penetrability of gamma radiation. Sensory analysis showed greater acceptance of the judges for the samples irradiated with E.B and G.R at the dose of 10 kGy. We concluded

  2. Variability of the pitch angle distribution of radiation belt ultrarelativistic electrons during and following intense geomagnetic storms: Van Allen Probes observations

    Science.gov (United States)

    Zou, Z.; Ni, B.; Gu, X.; Zhao, Z.; Zhou, C.

    2015-12-01

    Fifteen month of pitch angle resolved Van Allen Probes Relativistic Electron-Proton Telescope (REPT) measurements of differential electron flux are analyzed to investigate the characteristics of the pitch angle distribution of radiation belt ultrarelativistic(> 2 MeV) electrons during storm conditions and during the long-storm decay. By modeling the ultrarelativistic electron pitch angle distribution as ,where is the equatorial pitch angle we examine the spatiotemporal variations of n value. The results show that in general n values increases with the level of geomagnetic activity. In principle the ultrarelativistic electrons respond to geomagnetic storms by becoming peaked at 90° pitch angle with n-values of 2 - 3 as a supportive signature of chorus acceleration outside the plasmasphere. High n-values also exists inside the plasmasphere, being localized adjacent to the plasmapause and energy dependent, which suggests a significant contribution from electronmagnetic ion cyclotron (EMIC) waves scattering. During quiet periods, n values generally evolve to become small, i.e., 0-1. The slow and long-term decays of the ultrarelativistic electrons after geomagnetic storms, while prominent, produce energy and L-shell-dependent decay time scales in association with the solar and geomagnetic activity and wave-particle interaction processes. At lower L shells inside the plasmasphere, the decay time scales for electrons at REPT energies are generally larger, varying from tens of days to hundreds of days, which can be mainly attributed to the combined effect of hiss-induced pitch angle scattering and inward radial diffusion. As L shell increases to L~3.5, a narrow region exists (with a width of ~0.5 L), where the observed ultrarelativistic electrons decay fastest, possibly resulting from efficient EMIC wave scattering. As L shell continues to increase, generally becomes larger again, indicating an overall slower loss process by waves at high L shells. Our investigation based

  3. Infrared radiation method for measuring ice segregation temperature of artificially frozen soils

    Institute of Scientific and Technical Information of China (English)

    Zhou Guoqing; Zhang Qi; Xu Zhiwei; Zhou Yang

    2012-01-01

    In order to study the evolution of the freezing fringe and final lenses of frost susceptible soils and advance the understanding of frost heave and mechanism of frost heave control,we used an open one-dimensional frost heave test system of infrared radiation technology,instead of a traditional thermistor method.Temperatures of the freezing fringe and segregated ice were measured in a non-contact mode.The results show that accurate and precise temperatures of ice segregation can be obtained by infrared thermal imaging systems.A self-developed inversion program inverted the temperature field of frozen soils.Based on our analysis of temperature variation in segregated ice and our study of the relationship between temperature and rate of ice segregation in cooling and warming processes during intermittent freezing,the mechanism of decreasing frost heave of frozen soils by controlling the growth of final lenses with an intermittent freezing mode,can be explained properly.

  4. Radiation exposure effects on the performance of an electrically trainable artificial neural network (ETANN)

    International Nuclear Information System (INIS)

    The authors present the effects of radiation exposure on an analog neural network device. The neural network implements a fully parallel architecture integrating 10,240 analog non-volatile synapses fabricated in a CMOS process. Graceful degradation of forward propagation performance analog non-volatile synapses fabricated in a CMOS process. Graceful degradation of forward propagation performance was observed in units that were exposed to absorbed doses of up to 26 Krads (Si) of 10 MeV electrons. The units were exposed without bias, except for that due to the floating gates. Single chip solutions to two pattern recognition problems representing two levels of difficulty are employed for testing. Post-irradiation-effects are observed over the following weeks after exposure due to latent charge trapping mechanism in the oxides of the non-volatile floating gate structures. They show that with the suitable algorithm and model, units with apparently permanent damage can be retrained to 100% recognition performance

  5. Non-stormtime injection of energetic particles into the slot-region between Earth's inner and outer electron radiation belts as observed by STSAT-1 and NOAA-POES

    OpenAIRE

    Park, J.; Min, K W; Summers, D.; Hwang, J; Kim, H. J.; Horne, Richard B.; Kirsch, Peter; Yumoto, K.; Uozumi, T.; Lühr, H.; J. Green

    2010-01-01

    The slot-region between Earth's inner and outer electron radiation belts was observed on 24 February 2004 by the satellite STSAT-1 to be populated by quasi-trapped electrons of energy 100-400 keV. This injection lasted for several hours and took place during a non-stormtime substorm. This appears to be the first observation of a slot-region electron injection that did not occur during a geomagnetic storm. We also report multi-instrument observations of this event from NOAA-POES and CPMN magne...

  6. Effect of dose fractionation on the enhancement by radiation or cyclophosphamide of artificial pulmonary metastases

    International Nuclear Information System (INIS)

    Thoracic irradiation of cyclophosphamide (CP) treatment of mice before an i.v. injection of tumour cells enhances the number of lung colonies produced by a factor of up to 100+. The effect of fractionation of the X-ray or CP dose on this phenomenon was investigated in several ways. The dose-response curve for the number of lung colonies as a function of the dose of thoracic irradiation was linear, and the degree of enhancement was independent of the number of tumour cells injected. Splitting a dose of 1,000 rad into 2 equal fractions separated by times varying from 1 to 24 h gave the same enhancement as that produced by a single dose of 1000 rad. Similarly, fractionation of 1000 rad into 5X200 rad, or 2000 rad into 5X400 rad (each interval between fractions being 3 h) had no effect on the radiation enhancement of colony formation. A single dose of 200 mg/kg of CP was compared with 3 doses of 66.7 mg/kg (each dose separated by 12 h) and with a continuous infusion of 200 mg/kg given over 24 h. In this case, fractionation and infusion produced a small reduction in the CP-induced increase, but the factor of colony enhancement compared to control mice remained >100. These data emphasize the potential hazard of prophylactic treatment of pulmonary metastases by X-rays or CP in clinical situations in which control of the primary tumour is not achieved. (author)

  7. Estimation of global solar radiation using an artificial neural network based on an interpolation technique in southeast China

    Science.gov (United States)

    Zou, Ling; Wang, Lunche; Lin, Aiwen; Zhu, Hongji; Peng, Yuling; Zhao, Zhenzhen

    2016-08-01

    Solar radiation plays important roles in energy application, vegetation growth and climate change. Empirical relations and machine-learning methods have been widely used to estimate global solar radiation (GSR) in recent years. An artificial neural network (ANN) based on spatial interpolation is developed to estimate GSR in southeast China. The improved Bristow-Campbell (IBC) model and the improved Ångström-Prescott (IA-P) model are compared with the ANN model to explore the best model in solar radiation modeling. Daily meteorological parameters, such as sunshine duration hours, mean temperature, maximum temperature, minimum temperature, relative humidity, precipitation, air pressure, water vapor pressure, and wind speed, along with station-measured GSR and a daily surface GSR dataset over China obtained from the Data Assimilation and Modeling Center for Tibetan Multi-spheres (DAM), are used to predict GSR and to validate the models in this work. The ANN model with the network of 9-17-1 provides better accuracy than the two improved empirical models in GSR estimation. The root-mean-square error (RMSE), mean bias error (MBE), and determination coefficient (R2) are 2.65 MJ m-2, -0.94 MJ m-2, and 0.68 in the IA-P model; 2.19 MJ m-2, 1.11 MJ m-2, and 0.83 in the IBC model; 1.34 MJ m-2, -0.11 MJ m-2, and 0.91 in the ANN model, respectively. The regional monthly mean GSR in the measured dataset, DAM dataset, and ANN model is analyzed. The RMSE (RMSE %) is 1.07 MJ m-2 (8.91%) and the MBE (MBE %) is -0.62 MJ m-2 (-5.21%) between the measured and ANN-estimated GSR. The statistical errors of RMSE (RMSE %) are 0.91 MJ m-2 (7.28%) and those of MBE (MBE %) are -0.15 MJ m-2 (-1.20%) between DAM and ANN-modeled GSR. The correlation coefficients and R2 are larger than 0.95. The regional mean GSR is 12.58 MJ m-2. The lowest GSR is observed in the northwest area, and it increases from northwest to southeast. The annual mean GSR decreases by 0.02 MJ m-2 decade-1 over the entire

  8. Influence of UV radiation on location of the photonic band gap and the refractive index of nanocomposite on the basis of artificial opal

    International Nuclear Information System (INIS)

    Influence of the high power N2 laser irradiation on the photonic band gap (PBG) of the bare and ZnO nanocrystal's filled artificial opal are investigated. It is found that long-term exposure to UV radiation leads to a long-wavelength shift of the nanocomposite's PBG due to changes in refractive index of SiO2 spheres, forming opal. Filling the pores of opal with ZnO nanocrystals increases this phenomenon due to increased efficiency of UV radiation absorption by nanocrystals ZnO. (authors)

  9. Risk from exposure to natural and artificial ultraviolet radiation; Il rischio di esposizione alla radiazione ultravioletta naturale e artificiale

    Energy Technology Data Exchange (ETDEWEB)

    Matzeu, M. [Istituto Superiore di Sanita`, Rome (Italy). Lab. di Fisica

    1998-12-31

    The association between exposure to ultraviolet (UV) and damage to the skin and eyes is today generally accepted. Exposure to UV radiation may occur in several ways. Apart from the sun, there is a wide range of artificial sources used in different fields of industry, research and medicine, the exposure to which adds to the total exposure of an individual during his life-span. The potential effects of ozone layer depletion on the increase of the solar UV radiation at earth`s surface, and therefor on human health, have recently been emphasized. Moreover, great attention has been devoted to the often uncontrolled use of UV lamps for tanning. This report shows the basis on which short and long term UV risk is assessed, and indicates some parameters necessary to its evaluation. The UV effects, both at molecular and cellular levels and on humans, are described together with their respective action spectra. The most common UV sources are then analyzed and their use in different fields is shown. Finally, some methods in dosimetry, which are useful for the correct measurement of exposure values, are described. [Italiano] E` oggi generalmente accettata l`assciazione tra l`esposizione alla radiazione UV e alcuni danni alla pelle e agli occhi (carcinomi e cataratta). Le occasioni di esposizione sono molteplici; oltre al sole, anche una grande varieta` di sorgenti artificiali impiegate per scopi diversi nell`industria, nella ricerca e in medicina danno un contributo, non sempre valutabile, all`esposizione totale di un individuo nell`arco della sua vita. Recentemente e` stato posto l`accento sulle possibili conseguenze della riduzione dello stato di ozono stratosferico sull`aumento della frazione di UV solare al suolo e quindi sulla salute umana; particolare attenzione ha inoltre suscitato l`uso, spesso incontrollato, delle lampade UV per scopi estetici. Sono illustrate le basi sulle quali viene riconosciuto il rischio a breve e a lungo termine e sono definiti i parametri

  10. Riding the belt

    Energy Technology Data Exchange (ETDEWEB)

    Potts, A.

    1998-04-01

    Recent developments in conveyor systems have focused on accessories rather than the belt itself. Radio frequency identification (RFID) is a technology using transponders embedded in conveyor belts and this is the latest development at the German firm Contitech. The system described in the articles developed with Moers, features transponders for cooling, controlling and monitoring conveyor belts. Other developments mentioned include a JOKI drum motor featuring a fully integrated gearbox and electric motor enclosed in a steel shell, from Interoll; a new scraper cleaning system from Hosch, new steel cord belting from Fenner, a conveying system for Schleenhain lignite opencast mine by FAM Foerdelantigen Magdeburg; new bearings from Nadella (the sales arm of Intersoll-Rand), an anti-shock belt transfer table from Rosta and new caliper disc brakes from GE Industrial.

  11. Deterministic methods for the relativistic Vlasov-Maxwell equations and the Van Allen belts dynamics

    International Nuclear Information System (INIS)

    Artificial satellites operate in an hostile radiation environment, the Van Allen radiation belts, which partly condition their reliability and their lifespan. In order to protect them, it is necessary to characterize the dynamics of the energetic electrons trapped in these radiation belts. This dynamics is essentially determined by the interactions between the energetic electrons and the existing electromagnetic waves. This work consisted in designing a numerical scheme to solve the equations modelling these interactions: the relativistic Vlasov-Maxwell system of equations. Our choice was directed towards methods of direct integration. We propose three new spectral methods for the momentum discretization: a Galerkin method and two collocation methods. All of them are based on scaled Hermite functions. The scaling factor is chosen in order to obtain the proper velocity resolution. We present in this thesis the discretization of the one-dimensional Vlasov-Poisson system and the numerical results obtained. Then we study the possible extensions of the methods to the complete relativistic problem. In order to reduce the computing time, parallelization and optimization of the algorithms were carried out. Finally, we present 1Dx-3Dv (mono-dimensional for x and three-dimensional for velocity) computations of Weibel and whistler instabilities with one or two electrons species. (author)

  12. Energetic neutron and gamma-ray spectra under the earth radiation belts according to "SALYUT-7" [correction of "SALUTE-7"]-"KOSMOS-1686" orbital complex and "CORONAS-I" satellite data.

    Science.gov (United States)

    Bogomolov, A V; Dmitriev, A V; Myagkova, I N; Ryumin, S P; Smirnova, O N; Sobolevsky, I M

    1998-01-01

    The spectra of neutrons >10 MeV and gamma-rays 1.5-100 MeV under the Earth Radiation Belts, restored from the data, obtained onboard orbital complex "SALYUT-7" [correction of "SALUTE-7"]-"KOSMOS-1686", are presented. The spectra shapes are similar to those for albedo neutrons and gamma-rays, but absolute values of their fluxes (0.2 cm-2 s-1 for neutrons, 0.8 cm-2 s-1 for gamma-rays at the equator and 1.2 cm-2 s-1, 1.9 cm-2 s-1, accordingly, at L=1.9) are several times as large. It is possibly explained by the fact that most of the detected particles were produced by the cosmic ray interactions with the orbital complex matter. Neutron and gamma-ray fluxes obtained from "CORONAS-1" data are near those for albedo particles. PMID:11542904

  13. Artificial intelligence

    CERN Document Server

    Hunt, Earl B

    1975-01-01

    Artificial Intelligence provides information pertinent to the fundamental aspects of artificial intelligence. This book presents the basic mathematical and computational approaches to problems in the artificial intelligence field.Organized into four parts encompassing 16 chapters, this book begins with an overview of the various fields of artificial intelligence. This text then attempts to connect artificial intelligence problems to some of the notions of computability and abstract computing devices. Other chapters consider the general notion of computability, with focus on the interaction bet

  14. The Development of Radiation hardened tele-robot system - Development of artificial force reflection control for teleoperated mobile robots

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ju Jang; Hong, Sun Gi; Kang, Young Hoon; Kim, Min Soeng [Korea Advanced Institute of Science and Technology, Taejon (Korea)

    1999-04-01

    One of the most important issues in teleoperation is to provide the sense of telepresence so as to conduct the task more reliably. In particular, teleoperated mobile robots are needed to have some kinds of backup system when the operator is blind for remote situation owing to the failure of vision system. In the first year, the idea of artificial force reflection was researched to enhance the reliability of operation when the mobile robot travels on the plain ground. In the second year, we extend previous results to help the teleoperator even when the robot climbs stairs. Finally, we apply the developed control algorithms to real experiments. The artificial force reflection method has two modes; traveling on the plain ground and climbing stairs. When traveling on the plain ground, the force information is artificially generated by using the range data from the environment while generating the impulse force when climbing stairs. To verify the validity of our algorithm, we develop the simulator which consists of the joystick and the visual display system. Through some experiments using this system, we confirm the validity and effectiveness of our new idea of artificial force reflection in the teleoperated mobile robot. 11 refs., 30 figs. (Author)

  15. Radiation-curable impregnating agents for the conservation of archaeologic wooden objects (part 3) and conservation experiments applying these agents to intact and artificially decayed wood samples

    International Nuclear Information System (INIS)

    As a continuation of the work described in the reports OEFZS Ber. No. 4165 and No. 4195, impregnating agents curable by ionizing radiation such as polymerizable monomers or artificial resins have been investigated. Specific weight and viscosity of the liquid mixtures have been as well determined as the specific weight and gel content of the gamma radiation-cured samples. Hardness and elastic behaviour have been estimated only, the shrinkage during hardening has been calculated. In continuation of OEFZS Ber. No. 4198, conservation experiments have been performed with selected impregnating agents by applying these agents to intact and chemically decayed wood samples, whereby the monomer uptake, the alteration of dimensions and volume and the deformation of the samples have been taken for the evaluation of the impregnating agents. (Author)

  16. Dynamic characteristics of conveyor belts

    Institute of Scientific and Technical Information of China (English)

    HOU You-fu; MENG Qing-rui

    2008-01-01

    The dynamic characteristics of a belt conveyor are determined to a large extent by the properties of the belt. This paper describes experiments designed to establish the dynamic properties of belting material. The dynamic elastic modulus, viscous damping and theological constants of the belt were measured. Several properties were studied as a function of the tensile loading on the belt. These included longitudinal vibration, the natural vibration frequency in the transverse direction and the response to an impulse excitation. Vibration response was observed under several different excitation frequencies. Most of these properties have not been tested previously under conditions appropriate for the ISO/DP9856 standard. Two types of belt were tested, a steel reinforced belt and a fabric reinforced belt. The test equipment was built to provide data appropriate for designing belt conveyors. It was observed that the stress wave propagation speed increased with tensile load and that tensile load was the main factor influencing longitudinal vibrations.

  17. The JET belt limiter

    International Nuclear Information System (INIS)

    A limiter with an effective area in contact with the plasma of about 16 m2 is presently being manufactured for installation in 1987. This belt limiter consists of two toroidal rings located above and below the equatorial plane of the vacuum vessel. Each of the two rings comprises a structure with water cooling pipes and fins welded to the pipes. The limiter material in contact with the plasma (graphite or beryllium) is inserted between fins in the form of tiles. The belt limiter is designed to handle up to 40 MW of total power at flux densities of 3 - 5 MW/m2 for 10 s and to permit rapid exchange of different limiter materials. The design and manufacture of the belt limiter and the results of thermomechanical analysis for different edge properties, power levels and shot repetition rates, are reported. (author)

  18. The jet belt limiter

    International Nuclear Information System (INIS)

    A limiter with an effective area in contact with the plasma of about 16 m/sup 2/ is presently being manufactured for installation in 1987. This belt limiter consists of two toroidal rings located above and below the equatorial plane of the vacuum vessel. Each of the two rings comprises a structure with water cooling pipes and fins welded to the pipes. The limiter material in contact with the plasma (graphite or beryllium) is inserted between fins in the form of tiles. The belt limiter is designed to handle up to 40 MW of total power at flux densities of 3 - 5 MW/m/sup 2/ for 10 s and to permit rapid exchange of different limiter materials. This paper describes the design and manufacture of the belt limiter and the results of thermomechanical analysis for different edge properties, power levels and shot repetition rates

  19. Intensification of biodiesel production from waste goat tallow using infrared radiation: Process evaluation through response surface methodology and artificial neural network

    International Nuclear Information System (INIS)

    Highlights: • Enhanced and significantly accelerated biodiesel synthesis from waste goat tallow by infrared radiation. • In situ water removal by adsorbent profoundly promotes achieving high free fatty acids (FFAs) conversion. • Process optimization and parametric interaction-effects assessment by response surface method. • Artificial Neural Network Modeling for prediction of triglycerides and FFA conversion. • At optimal conditions, product biodiesel contains 98.5 wt.% FAME. - Abstract: For the first time, an efficient simultaneous trans/esterification process for biodiesel synthesis from waste goat tallow with considerable free fatty acids (FFAs) content has been explored employing an infrared radiation assisted reactor (IRAR). The impacts of methanol to tallow molar ratio, IRAR temperature and H2SO4 concentration on goat tallow conversion were evaluated by response surface methodology (RSM). Under optimal conditions, 96.7% FFA conversion was achieved within 2.5 h at 59.93 wt.% H2SO4, 69.97 °C IRAR temperature and 31.88:1 methanol to tallow molar ratio. The experimental results were also modeled using artificial neural network (ANN) and marginal improvement in modeling efficiency was observed in comparison with RSM. The infrared radiation strategy could significantly accelerate the conversion process as demonstrated through a substantial reduction in reaction time compared to conventionally heated reactor while providing appreciably high biodiesel yield. Moreover, the in situ water removal using silica-gel adsorbent could also facilitate achieving higher FFA conversion to fatty acid methyl ester (FAME). Owing to the occurrence of simultaneous transesterification of triglycerides present in goat tallow, overall 98.5 wt.% FAME content was determined at optimal conditions in the product biodiesel which conformed to ASTM and EN biodiesel specifications

  20. Artificial Limbs

    Science.gov (United States)

    ... you are missing an arm or leg, an artificial limb can sometimes replace it. The device, which ... activities such as walking, eating, or dressing. Some artificial limbs let you function nearly as well as ...

  1. LifeSat - Radiation research

    International Nuclear Information System (INIS)

    Spaceflight crews will be exposed to levels of radiation which exceed those experienced on the ground. In order to reduce the uncertainty in the evaluation of risks it is necessary to validate the responses of biological systems in space under conditions which simulate exposure levels expected during exploration class missions. The LifeSat system provides the experimental capabilities to satisfy these goals. Specifically, LifeSat is capable of long duration flights of up to 60 days, is able to fly directly into trapped radiation belts and in circular or eccentric polar orbits, has the ability to provide artificial gravity and imposes fewer restrictions than the STS on the use of hazardous materials such as chemical fixatives. These features along with reference missions and experiments are discussed with respect to radiation research goals

  2. Coal belt options

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-03-15

    Whether moving coal long distances overland or short distances in-plant, belt conveyors will always be in demand. The article reports on recent systems developments and applications by Beumer, Horizon Conveyor Equipment, Conveyor Dynamics, Doppelmayr Transport Technology, Enclosed Bulk Systems, ContiTech and Bateman Engineered Technologies. 2 photos.

  3. Dynamics of energetic electrons in the earth's outer radiation belt during 1968 as observed by the Lawrence Livermore National Laboratory's spectrometer on Ogo 5

    International Nuclear Information System (INIS)

    An account is given of measurements of electrons made by the LLNL magnetic electron spectrometer (60--3000 keV in seven differential energy channels) on the Ogo 5 satellite in the earth's outer-belt regions during 1968 and early 1969. The data were analyzed to identify those features dominated by pitch angle and radial diffusion; in doing so all aspects of phase space covered by the data were studied, including pitch angle distributions and spectral features, as well as decay rates. The pitch angle distributions are reported elsewhere. The spectra observed in the weeks after a storm at Lapprox.3--4.5 show the evolution of a peak at approx.1.5 MeV and pronounced minima at approx.0,5 MeV. The observed pitch angle diffusion lifetimes are identified as being the shortest decays observed and are found to be highly energy and L dependent with minimum lifetimes of approx.1--2 days occurring at L approx.3--4.5. Two contiguous periods of decay, following the intense storm injection on October 31 and November 1, were analyzed in terms of radial diffusion. Significant differences were found between the derived values of D/sub L/L for the two periods; also significant energy dependence shows in the results. Although the values of D/sub L/L vary by about a factor of 10, representative values are 0.3 day-1 at L = 6, 0.06 at L = 4, 0.015 at L = 3, and 0.001 at L = 2.5. Despite the wide variation of many prior results in the literature, there is a family of results in approximate agreement with the present results. By noting the variations in D/sub L/L, as a function of the invariant quantities, we are able to order a fair body of previous results with our new results

  4. Control of the radiative level shift and linewidth of a superconducting artificial atom through a variable boundary condition

    International Nuclear Information System (INIS)

    We investigate the dynamics of a superconducting qubit strongly coupled to a semi-infinite one-dimensional microwave field having a variable boundary condition. The radiative level shift and linewidth of the qubit are controllable through the boundary condition of the field, and the spectral properties of the output microwave are modified accordingly. The current scheme provides a compact method for controlling the radiative characteristics of quantum few-level systems that is useful in single-photon engineering. (paper)

  5. Application of the artificial neural network for reconstructing the internal-structure image of a random medium by spatial characteristics of backscattered optical radiation

    International Nuclear Information System (INIS)

    The feasibility of using an artificial neural network (ANN), which is the standard Matlab tool, for non-invasive (based on the data of backscattering) diagnostics of macro-inhomogeneities, localised at subsurface layers of the turbid strongly scattering medium was shown. The spatial and angle distribution of the backscattered optical radiation was calculated by using the Monte-Carlo method combining the modelling of effective optical paths and the use of statistical weights. It was shown that application of the backscattering method together with the ANN allows solving inverse problems for determining the average radius of the scattering particles and for reconstructing the images of structural elements within the medium with a high accuracy. (special issue devoted to application of laser technologies in biophotonics and biomedical studies)

  6. Metamorphic belts of Anatolia

    Science.gov (United States)

    Oberhänsli, Roland; Prouteau, Amaury; Candan, Osman; Bousquet, Romain

    2015-04-01

    Investigating metamorphic rocks from high-pressure/low-temperature (HP/LT) belts that formed during the closure of several oceanic branches, building up the present Anatolia continental micro-plate gives insight to the palaeogeography of the Neotethys Ocean in Anatolia. Two coherent HP/LT metamorphic belts, the Tavşanlı Zone (distal Gondwana margin) and the Ören-Afyon-Bolkardağ Zone (proximal Gondwana margin), parallel their non-metamorphosed equivalent (the Tauride Carbonate Platform) from the Aegean coast in NW Anatolia to southern Central Anatolia. P-T conditions and timing of metamorphism in the Ören-Afyon-Bolkardağ Zone (>70?-65 Ma; 0.8-1.2 GPa/330-420°C) contrast those published for the overlying Tavşanlı Zone (88-78 Ma; 2.4 GPa/500 °C). These belts trace the southern Neotethys suture connecting the Vardar suture in the Hellenides to the Inner Tauride suture along the southern border of the Kirşehir Complex in Central Anatolia. Eastwards, these belts are capped by the Oligo-Miocene Sivas Basin. Another HP/LT metamorphic belt, in the Alanya and Bitlis regions, outlines the southern flank of the Tauride Carbonate Platform. In the Alanya Nappes, south of the Taurides, eclogites and blueschists yielded metamorphic ages around 82-80 Ma (zircon U-Pb and phengite Ar-Ar data). The Alanya-Bitlis HP belt testifies an additional suture not comparable to the northerly Tavşanlı and Ören-Afyon belts, thus implying an additional oceanic branch of the Neotethys. The most likely eastern lateral continuation of this HP belt is the Bitlis Massif, in SE Turkey. There, eclogites (1.9-2.4 GPa/480-540°C) occur within calc-arenitic meta-sediments and in gneisses of the metamorphic (Barrovian-type) basement. Zircon U-Pb ages revealed 84.4-82.4 Ma for peak metamorphism. Carpholite-bearing HP/LT metasediments representing the stratigraphic cover of the Bitlis Massif underwent 0.8-1.2 GPa/340-400°C at 79-74 Ma (Ar-Ar on white mica). These conditions compares to the Tav

  7. Role of Dipicolinic Acid in Survival of Bacillus subtilis Spores Exposed to Artificial and Solar UV Radiation

    OpenAIRE

    Slieman, Tony A.; Nicholson, Wayne L.

    2001-01-01

    Pyridine-2,6-dicarboxylic acid (dipicolinic acid [DPA]) constitutes approximately 10% of Bacillus subtilis spore dry weight and has been shown to play a significant role in the survival of B. subtilis spores exposed to wet heat and to 254-nm UV radiation in the laboratory. However, to date, no work has addressed the importance of DPA in the survival of spores exposed to environmentally relevant solar UV radiation. Air-dried films of spores containing DPA or lacking DPA due to a null mutation ...

  8. Infrared Kuiper Belt Constraints

    International Nuclear Information System (INIS)

    We compute the temperature and IR signal of particles of radius a and albedo α at heliocentric distance R, taking into account the emissivity effect, and give an interpolating formula for the result. We compare with analyses of COBE DIRBE data by others (including recent detection of the cosmic IR background) for various values of heliocentric distance R, particle radius a, and particle albedo α. We then apply these results to a recently developed picture of the Kuiper belt as a two-sector disk with a nearby, low-density sector (40< R<50 endash 90 AU) and a more distant sector with a higher density. We consider the case in which passage through a molecular cloud essentially cleans the solar system of dust. We apply a simple model of dust production by comet collisions and removal by the Poynting-Robertson effect to find limits on total and dust masses in the near and far sectors as a function of time since such a passage. Finally, we compare Kuiper belt IR spectra for various parameter values. Results of this work include: (1) numerical limits on Kuiper belt dust as a function of (R, a, α) on the basis of four alternative sets of constraints, including those following from recent discovery of the cosmic IR background by Hauser et al.; (2) application to the two-sector Kuiper belt model, finding mass limits and spectrum shape for different values of relevant parameters including dependence on time elapsed since last passage through a molecular cloud cleared the outer solar system of dust; and (3) potential use of spectral information to determine time since last passage of the Sun through a giant molecular cloud. copyright copyright 1999. The American Astronomical Society

  9. Belt-up!

    Energy Technology Data Exchange (ETDEWEB)

    Woof, M.

    1999-07-01

    Advanced control systems, improved materials and new dust control systems have turned the humble conveyor belt into a sophisticated method for transporting materials. RJB Mining has improved productivity at the Price of Wales colliery in Yorkshire, UK, with the installation of Alstom`s VDM drive system; Qualter Hall`s upgraded conveyor system at the Rugely Power Station in the UK is proving its ability to minimise coal spillage. The article highlights advances by several manufacturers in conveyor technology. 5 photos.

  10. Effects of gamma radiation on phases of evolutional cycle of Corcyra cephalonica (Stainton, 1865) (Lepidoptera pyralidae) in artificial diet

    International Nuclear Information System (INIS)

    The effects of the increase in the gamma radiation (60 Co) doses on different phases of the evolutional cycle of Corcyra cephalonica (Stainton, 1865) (Lepidoptera Pyraliade) are studied. A cobalt 60 source type gamma beam 650 was used and the activity was of approximately 2.91 x 1014 Bq. The experiments were conducted under controlled conditions with temperature at 25 ± 20 C and relative humidity of 70 ± 10%. (M.A.C.)

  11. Lap belt injuries in children.

    LENUS (Irish Health Repository)

    McGrath, N

    2010-07-01

    The use of adult seat belts without booster seats in young children may lead to severe abdominal, lumbar or cervical spine and head and neck injuries. We describe four characteristic cases of lap belt injuries presenting to a tertiary children\\'s hospital over the past year in addition to a review of the current literature. These four cases of spinal cord injury, resulting in significant long-term morbidity in the two survivors and death in one child, arose as a result of lap belt injury. These complex injuries are caused by rapid deceleration characteristic of high impact crashes, resulting in sudden flexion of the upper body around the fixed lap belt, and consequent compression of the abdominal viscera between the lap belt and spine. This report highlights the dangers of using lap belts only without shoulder straps. Age-appropriate child restraint in cars will prevent these injuries.

  12. A survey of sources of incoherent artificial optical radiation in a hospital environment in accordance with European Directive 2006/25/EC: evaluation of the related exposure risk.

    Science.gov (United States)

    Cavatorta, Claudia; Lualdi, Manuela; Meroni, Silvia; Polita, Giovanni; Bolchi, Mauro; Pignoli, Emanuele

    2016-03-01

    The evaluation of incoherent artificial optical radiation (AOR) exposure in hospital environments is a complex task due to the variety of sources available. This study has been designed to provide a proposal for the precautionary assessment of the related risk. This survey suggested that, in our Institution, at least three kinds of AOR sources required specific investigations: ambient lighting, theatre operating lighting and ultraviolet radiation (UVR) sources. For each kind of evaluated sources a specific measurement approach was developed. All irradiance measurements were made using a commercial spectroradiometer. The obtained results were compared with the appropriate exposure limit values (ELVs) defined in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines and adopted by the European Directive 2006/25/EC. The risk related to the evaluated AOR exposure was finally assessed according to our risk matrix. According to our results, the emission of ambient lighting in the actual exposure conditions was always in accordance with the ELVs and the related risk was classifiable as not relevant. The risk related to the exposure to theatre operating lighting resulted not negligible, especially when two or more sources were used with focal spots overlapping on reflective objects. UVR sources emission may represent a health hazard depending, in particular, on the set up of the device containing the source. In case of laminar flow cabinets and closed transilluminators, if the UVR source is well contained within an enclosure with interlock, it presents no risk of exposure. Otherwise, the emission arising from UVR lamps, open transilluminators or sources not provided with interlock, may represent a risk classifiable as high even in the actual working conditions. The personal protective equipment used by workers were also assessed and their suitability was discussed. PMID:26909554

  13. Belt conveyor for recycle aggregate

    OpenAIRE

    Bezrodný, Roman

    2014-01-01

    This bachelor thesis deals with the belt conveyor for the transport of recycled aggregate in an oblique direction. The aim is to find constructional solutions to the belt conveyor for the assigned transport capacity of 95 000 kg per hour, and the assigned axial distance of 49 m and different height of 12 m. The thesis contains a brief description of the belt conveyor and a description of basic constructional components. It also contains a functional calculation of the capacity and forces acco...

  14. Artificial blood

    Directory of Open Access Journals (Sweden)

    Sarkar Suman

    2008-01-01

    Full Text Available Artificial blood is a product made to act as a substitute for red blood cells. While true blood serves many different functions, artificial blood is designed for the sole purpose of transporting oxygen and carbon dioxide throughout the body. Depending on the type of artificial blood, it can be produced in different ways using synthetic production, chemical isolation, or recombinant biochemical technology. Development of the first blood substitutes dates back to the early 1600s, and the search for the ideal blood substitute continues. Various manufacturers have products in clinical trials; however, no truly safe and effective artificial blood product is currently marketed. It is anticipated that when an artificial blood product is available, it will have annual sales of over $7.6 billion in the United States alone.

  15. SLH Timing Belt Powertrain

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Abe

    2014-04-09

    The main goal of this proposal was to develop and test a novel powertrain solution for the SLH hydroEngine, a low-cost, efficient low-head hydropower technology. Nearly two-thirds of U.S. renewable electricity is produced by hydropower (EIA 2010). According to the U.S. Department of Energy; this amount could be increased by 50% with small hydropower plants, often using already-existing dams (Hall 2004). There are more than 80,000 existing dams, and of these, less than 4% generate power (Blankinship 2009). In addition, there are over 800 irrigation districts in the U.S., many with multiple, non-power, low-head drops. These existing, non-power dams and irrigation drops could be retrofitted to produce distributed, baseload, renewable energy with appropriate technology. The problem is that most existing dams are low-head, or less than 30 feet in height (Ragon 2009). Only about 2% of the available low-head hydropower resource in the U.S. has been developed, leaving more than 70 GW of annual mean potential low-head capacity untapped (Hall 2004). Natel Energy, Inc. is developing a low-head hydropower turbine that operates efficiently at heads less than 6 meters and is cost-effective for deployment across multiple low-head structures. Because of the unique racetrack-like path taken by the prime-movers in the SLH, a flexible powertrain is required. Historically, the only viable technological solution was roller chain. Despite the having the ability to easily attach blades, roller chain is characterized by significant drawbacks, including high cost, wear, and vibration from chordal action. Advanced carbon- fiber-reinforced timing belts have been recently developed which, coupled with a novel belt attachment system developed by Natel Energy, result in a large reduction in moving parts, reduced mass and cost, and elimination of chordal action for increased fatigue life. The work done in this project affirmatively addressed each of the following 3 major uncertainties concerning

  16. The effects of artificially induced hyperglycaemia on the response of the Lewis lung carcinoma to radiation and cyclophosphamide

    International Nuclear Information System (INIS)

    In the treatment of any malignancy it is essential to utilize all known physiological differences that exist between tumour and normal tissue. One well established difference is that tumours, in both rodents and man, have a lower pH than normal tissue. Further reduction in tumour pH occurs in non-vascularised necrotic regions. It is now widely believed that cells, close to necrotic regions, distant from blood vessels are protected from the effects of radiation and chemotherapeutic agents by their hypoxia and reduced rate of proliferation, thus providing the foci for tumour regrowth. Yet, since these cells are situated in an acidic environment they should be the ones most susceptible to exploitation or modification of the tumour's acid:base status. Hyperglycaemia is known to increase tumour acidosis. The effect of such treatment on the tumour response to radiation or to chemotherapeutic agents is being assessed. Initial results indicate that hyperglycaemia can increase or reduce the response of the Lewis lung carcinoma to cyclophosphamide. The type of response obtained is dependent on the duration, level and timing of glucose treatments. Further work is now in progress

  17. Composition and origin of fluids associated with lode gold deposits in a Mesoarchean greenstone belt (Warrawoona Syncline, Pilbara Craton, Western Australia) using synchrotron radiation X-ray fluorescence

    Science.gov (United States)

    Thébaud, Nicolas; Philippot, Pascal; Rey, Patrice; Cauzid, Jean

    2006-10-01

    Microthermometry and Raman spectroscopy techniques are routinely use to constrain ore-fluids δ18O and molar proportions of anhydrous gas species (CO2, CH4, N2). However, these methods remain imprecise concerning the ore-fluids composition and source. Synchrotron radiation X-ray fluorescence allows access to major and trace element concentrations (Cl, Br and K, Ca, Fe, Cu, Zn, As, Rb, Sr) of single fluid inclusion. In this paper, we present the results of the combination of these routine and newly developed techniques in order to document the fluids composition and source associated with a Mesoarchaean lode gold deposit (Warrawoona Syncline, Western Australia). Fluid inclusion analyses show that quartz veins preserved records of three fluid inclusion populations. Early fluids inclusions, related to quartz veins precipitation, are characterized by a moderate to high Br/Cl ratio relative to modern seawater, CO2 ± CH4 ± N2, low to moderate salinities and significant base metal (Fe, Cu, Zn) and metalloid (As) concentrations. Late fluid inclusions trapped in secondary aqueous fluid inclusions are divided into two populations with distinct compositions. The first population consists of moderately saline aqueous brines, with a Br/Cl ratio close to modern seawater and a low concentration of base metals and metalloids. The second population is a fluid of low to moderate salinity, with a low Br/Cl ratio relative to modern seawater and significant enrichment in Fe, Zn, Sr and Rb. These three fluid inclusion populations point to three contrasting sources: (1) a carbonic fluid of mixed metamorphic and magmatic origin associated with the gold-bearing quartz precipitation; (2) a secondary aqueous fluid with seawater affinity; and (3) a surface-derived secondary aqueous fluid modified through interaction with felsic lithologies, before being flushed into the syncline. Primary carbonic fluids present similar characteristics than those ascribed to Mesoarchaean lode gold deposits

  18. Effects evaluation of artificial aging by temperature and gamma radiation on cables for Laguna Verde nuclear power plant (LVNPP)

    International Nuclear Information System (INIS)

    A set of tests has been carried out at the Equipment Qualification Laboratory at National Institute of Nuclear Research to perform accelerated aging up to 60 years under temperature and gamma radiation environment for electrical cables. The results obtained from such tests are the base line data for comparison to with the current cable conditions at the plant. This work is intended for establishing the cable aging management program for the Laguna Verde nuclear power plant (LVNPP). For such purpose, the Institute has prepared methodologies and procedures to apply condition monitoring techniques in accelerated aging tests on samples of new cables drawn from the LVNPP warehouse. The condition indicators of the material selected for condition monitoring and the aging management process of cables were: Elongation at Break (EAB) and Oxidation Induction Time (OIT). A cable aging management program includes activities for cable selection, determination of condition indicators of the cable materials (EAB, OIT, Ind enter), accelerated aging of cable samples at the laboratory, analysis of maintenance history, operational experience of the plant and analysis of the environmental and service conditions (temperature and gamma radiation), as well as the establishment of a condition monitoring plan for cables in the plant. Two cable model samples were thermally aged and gamma irradiated with doses corresponding to differential operational periods. EAB and OIT values of cable insulating material (ethylene propylene and cross linked polyethylene) were obtained. It was found that the EAB and OIT data correlation is very closed, and it could be applied to infer values that are not possible to measure directly at the plant and be used for cable aging evaluation and remaining life time determination. (Author)

  19. Artificial intelligence

    CERN Document Server

    Ennals, J R

    1987-01-01

    Artificial Intelligence: State of the Art Report is a two-part report consisting of the invited papers and the analysis. The editor first gives an introduction to the invited papers before presenting each paper and the analysis, and then concludes with the list of references related to the study. The invited papers explore the various aspects of artificial intelligence. The analysis part assesses the major advances in artificial intelligence and provides a balanced analysis of the state of the art in this field. The Bibliography compiles the most important published material on the subject of

  20. Artificial urushi.

    Science.gov (United States)

    Kobayashi, S; Uyama, H; Ikeda, R

    2001-11-19

    A new concept for the design and laccase-catalyzed preparation of "artificial urushi" from new urushiol analogues is described. The curing proceeded under mild reaction conditions to produce the very hard cross-linked film (artificial urushi) with a high gloss surface. A new cross-linkable polyphenol was synthesized by oxidative polymerization of cardanol, a phenol derivative from cashew-nut-shell liquid, by enzyme-related catalysts. The polyphenol was readily cured to produce the film (also artificial urushi) showing excellent dynamic viscoelasticity. PMID:11763444

  1. Geography of the asteroid belt

    Science.gov (United States)

    Zellner, B. H.

    1978-01-01

    The CSM classification serves as the starting point on the geography of the asteroid belt. Raw data on asteroid types are corrected for observational biases (against dark objects, for instance) to derive the distribution of types throughout the belt. Recent work on family members indicates that dynamical families have a true physical relationship, presumably indicating common origin in the breakup of a parent asteroid.

  2. Artificial Reefs

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — An artificial reef is a human-made underwater structure, typically built to promote marine life in areas with a generally featureless bottom, control erosion, block...

  3. Natural - synthetic - artificial!

    DEFF Research Database (Denmark)

    Nielsen, Peter E

    2010-01-01

    The terms "natural," "synthetic" and "artificial" are discussed in relation to synthetic and artificial chromosomes and genomes, synthetic and artificial cells and artificial life.......The terms "natural," "synthetic" and "artificial" are discussed in relation to synthetic and artificial chromosomes and genomes, synthetic and artificial cells and artificial life....

  4. Evaluation of the static belt fit provided by belt-positioning booster seats.

    Science.gov (United States)

    Reed, Matthew P; Ebert, Sheila M; Sherwood, Christopher P; Klinich, Kathleen D; Manary, Miriam A

    2009-05-01

    Belt-positioning booster seats are recommended for children who use vehicle seat belts as primary restraints but who are too small to obtain good belt fit. Previous research has shown that belt-positioning boosters reduce injury risk, but the belt fit produced by the wide range of boosters in the US market has not previously been assessed. The present study describes the development of a method for quantifying static belt fit with a Hybrid-III 6-year-old test dummy. The measurement method was applied in a laboratory seat mockup to 31 boosters (10 in both backless and highback modes) across a range of belt geometries obtained from in-vehicle measurements. Belt fit varied widely across boosters. Backless boosters generally produced better lap belt fit than highback boosters, largely because adding the back component moved the dummy forward with respect to the lap belt routing guides. However, highback boosters produced more consistent shoulder belt fit because of the presence of belt routing guides near the shoulder. Some boosters performed well on both lap belt and shoulder belt fit. Lap belt fit in dedicated boosters was generally better than in combination restraints that also can be used with an integrated harness. Results demonstrate that certain booster design features produce better belt fit across a wide range of belt geometries. Lap belt guides that hold the belt down, rather than up, and shoulder belt guides integrated into the booster backrest provided better belt fit. PMID:19393812

  5. Gamma-H2AX as a biomarker of DNA damage induced by ionizing radiation in targeted and bystander human artificial skin models and peripheral blood lymphocytes

    Science.gov (United States)

    Redon, Christophe; Dickey, Jennifer; Bonner, William; Sedelnikova, Olga

    Ionizing radiation (IR) exposure is inevitable. In addition to exposure from cosmic rays, the sun and radioactive substances, modern society has created new sources of radiation exposure such as space and high altitude journeys, X-ray diagnostics, radiological treatments and the increasing threat of radiobiological terrorism. For these reasons, a reliable, reproducible and sensitive assessment of dose and time exposure to IR is essential. We developed a minimally invasive diagnostic test for IR exposure based on detection of a phosphorylated variant of histone H2AX (gamma-H2AX), which occurs specifically at sites of DNA double-strand breaks (DSBs). The phosphorylation of thousands of H2AX molecules forms a gamma-H2AX focus in the chromatin flanking the DSB site that can be detected in situ. We analyzed gamma- H2AX focus formation in both directly irradiated cells as well as in un-irradiated "bystanders" in close contact with irradiated cells. In order to insure minimal invasiveness, we examined commercially available artificial skin models as a surrogate for human skin biopsies as well as peripheral blood lymphocytes. In human skin models, cells in a thin plane were microbeamirradiated and gamma-H2AX formation was measured both in irradiated and in distal bystander cells over time. In irradiated cells DSB formation reached a maximum at 15-30 minutes post- IR and then declined within several hours; all cells were affected. In marked contrast, the incidence of DSBs in bystander cells reached a maximum by 12-48 hours post-irradiation, gradually decreasing over the 7 day time course. At the maxima, 40-60% of bystander cells were affected. Similarly, we analyzed blood samples exposed to IR ex vivo at doses ranging from 0.02 to 3 Gy. The amount of DNA damage was linear in respect to radiation dose and independent of the age or sex of the blood donor. The method is highly reproducible and highly sensitive. In directly irradiated cells, the number of gamma-H2AX foci peaked

  6. Radiation

    International Nuclear Information System (INIS)

    The chapter one presents the composition of matter and atomic theory; matter structure; transitions; origin of radiation; radioactivity; nuclear radiation; interactions in decay processes; radiation produced by the interaction of radiation with matter

  7. Artificial noses.

    Science.gov (United States)

    Stitzel, Shannon E; Aernecke, Matthew J; Walt, David R

    2011-08-15

    The mammalian olfactory system is able to detect many more odorants than the number of receptors it has by utilizing cross-reactive odorant receptors that generate unique response patterns for each odorant. Mimicking the mammalian system, artificial noses combine cross-reactive sensor arrays with pattern recognition algorithms to create robust odor-discrimination systems. The first artificial nose reported in 1982 utilized a tin-oxide sensor array. Since then, however, a wide range of sensor technologies have been developed and commercialized. This review highlights the most commonly employed sensor types in artificial noses: electrical, gravimetric, and optical sensors. The applications of nose systems are also reviewed, covering areas such as food and beverage quality control, chemical warfare agent detection, and medical diagnostics. A brief discussion of future trends for the technology is also provided. PMID:21417721

  8. Artificial intelligence

    International Nuclear Information System (INIS)

    A vivid example of the growing need for frontier physics experiments to make use of frontier technology is in the field of artificial intelligence and related themes. This was reflected in the second international workshop on 'Software Engineering, Artificial Intelligence and Expert Systems in High Energy and Nuclear Physics' which took place from 13-18 January at France Telecom's Agelonde site at La Londe des Maures, Provence. It was the second in a series, the first having been held at Lyon in 1990

  9. Artificial Intelligence

    CERN Document Server

    Warwick, Kevin

    2011-01-01

    if AI is outside your field, or you know something of the subject and would like to know more then Artificial Intelligence: The Basics is a brilliant primer.' - Nick Smith, Engineering and Technology Magazine November 2011 Artificial Intelligence: The Basics is a concise and cutting-edge introduction to the fast moving world of AI. The author Kevin Warwick, a pioneer in the field, examines issues of what it means to be man or machine and looks at advances in robotics which have blurred the boundaries. Topics covered include: how intelligence can be defined whether machines can 'think' sensory

  10. Chaos on the conveyor belt

    CERN Document Server

    Sándor, Bulcsú; Tél, Tamás; Néda, Zoltán

    2013-01-01

    The dynamics of a spring-block train placed on a moving conveyor belt is investigated both by simple experiments and computer simulations. The first block is connected by spring to an external static point, and due to the dragging effect of the belt the blocks undergo complex stick-slip dynamics. A qualitative agreement with the experimental results can only be achieved by taking into account the spatial inhomogeneity of the friction force on the belt's surface, modeled as noise. As a function of the velocity of the conveyor belt and the noise strength, the system exhibits complex, self-organized critical, sometimes chaotic dynamics and phase transition-like behavior. Noise induced chaos and intermittency is also observed. Simulations suggest that the maximum complexity of the dynamical states is achieved for a relatively small number of blocks, around five.

  11. Artificial sweeteners

    DEFF Research Database (Denmark)

    Raben, Anne Birgitte; Richelsen, Bjørn

    2012-01-01

    Artificial sweeteners can be a helpful tool to reduce energy intake and body weight and thereby risk for diabetes and cardiovascular diseases (CVD). Considering the prevailing diabesity (obesity and diabetes) epidemic, this can, therefore, be an important alternative to natural, calorie-containin...

  12. Artificial photosynthesis

    OpenAIRE

    Andrew C. Benniston; Anthony Harriman

    2008-01-01

    We raise here a series of critical issues regarding artificial photosynthesis with the intention of increasing awareness about what needs to be done to bring about a working prototype. Factors under consideration include energy and electron transfers, coupled redox reactions, repair mechanisms, and integrated photosystems.

  13. Correction for 'artificial' electron disequilibrium due to cone-beam CT density errors: implications for on-line adaptive stereotactic body radiation therapy of lung.

    Science.gov (United States)

    Disher, Brandon; Hajdok, George; Wang, An; Craig, Jeff; Gaede, Stewart; Battista, Jerry J

    2013-06-21

    Cone-beam computed tomography (CBCT) has rapidly become a clinically useful imaging modality for image-guided radiation therapy. Unfortunately, CBCT images of the thorax are susceptible to artefacts due to scattered photons, beam hardening, lag in data acquisition, and respiratory motion during a slow scan. These limitations cause dose errors when CBCT image data are used directly in dose computations for on-line, dose adaptive radiation therapy (DART). The purpose of this work is to assess the magnitude of errors in CBCT numbers (HU), and determine the resultant effects on derived tissue density and computed dose accuracy for stereotactic body radiation therapy (SBRT) of lung cancer. Planning CT (PCT) images of three lung patients were acquired using a Philips multi-slice helical CT simulator, while CBCT images were obtained with a Varian On-Board Imaging system. To account for erroneous CBCT data, three practical correction techniques were tested: (1) conversion of CBCT numbers to electron density using phantoms, (2) replacement of individual CBCT pixel values with bulk CT numbers, averaged from PCT images for tissue regions, and (3) limited replacement of CBCT lung pixels values (LCT) likely to produce artificial lateral electron disequilibrium. For each corrected CBCT data set, lung SBRT dose distributions were computed for a 6 MV volume modulated arc therapy (VMAT) technique within the Philips Pinnacle treatment planning system. The reference prescription dose was set such that 95% of the planning target volume (PTV) received at least 54 Gy (i.e. D95). Further, we used the relative depth dose factor as an a priori index to predict the effects of incorrect low tissue density on computed lung dose in regions of severe electron disequilibrium. CT number profiles from co-registered CBCT and PCT patient lung images revealed many reduced lung pixel values in CBCT data, with some pixels corresponding to vacuum (-1000 HU). Similarly, CBCT data in a plastic lung

  14. Artificial Intelligence.

    Science.gov (United States)

    Lawrence, David R; Palacios-González, César; Harris, John

    2016-04-01

    It seems natural to think that the same prudential and ethical reasons for mutual respect and tolerance that one has vis-à-vis other human persons would hold toward newly encountered paradigmatic but nonhuman biological persons. One also tends to think that they would have similar reasons for treating we humans as creatures that count morally in our own right. This line of thought transcends biological boundaries-namely, with regard to artificially (super)intelligent persons-but is this a safe assumption? The issue concerns ultimate moral significance: the significance possessed by human persons, persons from other planets, and hypothetical nonorganic persons in the form of artificial intelligence (AI). This article investigates why our possible relations to AI persons could be more complicated than they first might appear, given that they might possess a radically different nature to us, to the point that civilized or peaceful coexistence in a determinate geographical space could be impossible to achieve. PMID:26957450

  15. Artificial intelligence

    OpenAIRE

    Duda, Antonín

    2009-01-01

    Abstract : Issue of this work is to acquaint the reader with the history of artificial inteligence, esspecialy branch of chess computing. Main attention is given to progress from fifties to the present. The work also deals with fighting chess programs against each other, and against human opponents. The greatest attention is focused on 1997 and duel Garry Kasparov against chess program Deep Blue. The work is divided into chapters according to chronological order.

  16. Single beam optical conveyor belt for chiral particles

    CERN Document Server

    Fernandes, David E

    2016-01-01

    We propose a novel paradigm to selectively manipulate and transport small engineered chiral particles and discriminate different enantiomers using unstructured chiral light. It is theoretically shown that the response of a chiral metamaterial particle may be tailored to enable an optical conveyor belt operation with no optical traps, such that for a fixed incident light helicity and independent of the nanoparticle location, it is either steadily pushed towards the direction of the photon flow or steadily pulled against the photon flow. Our findings create new opportunities for unconventional optical manipulations of tailored nanoparticles and may have applications in sorting racemic mixtures of artificial chiral molecules and in particle delivery.

  17. Launching jets from accretion belts

    CERN Document Server

    Schreier, Ron

    2016-01-01

    We propose that sub-Keplerian accretion belts around stars might launch jets. The sub-Keplerian inflow does not form a rotationally supported accretion disk, but it rather reaches the accreting object from a wide solid angle. The basic ingredients of the flow are a turbulent region where the accretion belt interacts with the accreting object via a shear layer, and two avoidance regions on the poles where the accretion rate is very low. A dynamo that is developed in the shear layer amplifies magnetic fields to high values. It is likely that the amplified magnetic fields form polar outflows from the avoidance regions. Our speculative belt-launched jets model has implications to a rich variety of astrophysical objects, from the removal of common envelopes to the explosion of core collapse supernovae by jittering jets.

  18. Kuiper Belts Around Nearby Stars

    CERN Document Server

    Nilsson, R; Brandeker, A; Olofsson, G; Pilbratt, G L; Risacher, C; Rodmann, J; Augereau, J -C; Bergman, P; Eiroa, C; Fridlund, M; Thébault, P; White, G J

    2010-01-01

    In order to detect and characterise cold extended circumstellar dust originating from collisions of planetesimal bodies in disks, belts, or rings at Kuiper-Belt distances (30--50\\,AU or beyond) sensitive submillimetre observations are essential. Measurements of the flux densities at these wavelengths will extend existing IR photometry and permit more detailed modelling of the Rayleigh-Jeans tail of the disks spectral energy distribution (SED), effectively constraining dust properties and disk extensions. By observing stars spanning from a few up to several hundred Myr, the evolution of debris disks during crucial phases of planet formation can be studied. // We have performed 870\\,$\\mu$m observations of 22 exo-Kuiper-Belt candidates, as part of a Large Programme with the LABOCA bolometer at the APEX telescope. Dust masses (or upper limits) were calculated from integrated 870\\,$\\mu$m fluxes, and fits to the SED of detected sources revealed the fractional dust luminosities $f_{\\mathrm{dust}}$, dust temperatures...

  19. Study of thermal conditions at belt slippage

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, R.; Pampel, W.; Pfleger, P.

    1987-04-01

    Conveyor belt slippage experiments are carried out on the Chrudim (Czechoslovakia) industrial sized test stand for belt widths up to 1 m and driving drum forces up to 400 kW. The stand is operated jointly by TAKRAF (GDR) and VITKOVICE VUTZ, Prague. From 1972 to 1981, 7 belt conveyor fires occurred in GDR brown coal surface mines due to belt slippage. One of these cases led to a belt fire after only 15 s at 100% belt slippage. Aim of the study was to determine accurate permissible slippage values. Design of the test stand is explained as well as test procedures with belt slippage at the driving drum varying between 10 and 100%. Belt driving parameters were measured along with temperature of the drum surface. The heat penetration parameter b (in kJ/m/sup 2/) was calculated. Maximum temperatures up to 150 C were measured on the drum during partial slippage and 370 C at 100% belt slippage. The ignition temperature of rubber abrasion fines was also analyzed and found to vary between 40 and 318 C, i.e. substantially lower than belt and drum layer ignition temperatures. Graphs and diagram of slippage measurement results are calculated. Values for permissible maximum slippage time for operating belt slippage monitoring devices are shown. These devices are required to be installed in the GDR at heavy mine belt conveyors with driving forces exceeding 500 kW. 8 refs.

  20. French experience in seat belt use.

    NARCIS (Netherlands)

    Lassarre, S. & Page, Y.

    1992-01-01

    This paper concerns the French experience in seat belt use. As well as the seat belt regulations, the strategies employed to reinforce the wearing of seat belts by using information and encouragement campaigns and checks by the police and gendarmerie are described here along with their timetables an

  1. Poleward expansion of the tropical belt derived from upper tropospheric water vapour

    OpenAIRE

    You, Qinglong; Min, Jinzhong; Kang, Shichang; Pepin, Nick

    2015-01-01

    Based on intersatellite-calibrated high-resolution infrared radiation sounder (HIRS) upper tropospheric water vapour (UTWV) brightness temperatures, the width of the tropical belt is defined as the distance between the latitudes at which maximum HIRS UTWV brightness temperatures are recorded in both hemispheres. Poleward expansion of the tropical belt is evident during 1979–2013 on an annual basis, with an average global magnitude of 1.57° latitude per decade. Most rapid widening is evident i...

  2. Global Storm-Time Depletion of the Outer Electron Belt

    Science.gov (United States)

    Ukhorskiy, A. Y.; Sitnov, M. I.; Millan, R. M.; Kress, B. T.; Fennell, J. F.

    2014-12-01

    The outer radiation belt consists of relativistic (≳0.5 MeV) electrons trapped on closed trajectories around Earth where its magnetic field is nearly dipolar. During increased geomagnetic activity electron intensities in the belt can vary by orders of magnitude at different spatial and temporal scale. The main phase of geomagnetic storms often produces deep depletions of electron intensities over broad regions of the outer belt. Previous studies identified three possible processes that can contribute to the depletions: fully adiabatic inflation of electron drift orbits caused the ring current growth, electron loss into the atmosphere due to pitch-angle scattering by plasma waves (e.g., EMIC and whistler waves), and electron escape through the magnetopause boundary. In this paper we investigate the relative importance of the magnetopause losses to the rapid depletion of the outer belt observed at the Van Allen Probes spacecraft during the main phase of March 17, 2013 storm. The intensities of > 1 MeV electrons were depleted by more that an order of magnitude over the entire radial extent of the belt in less than 6 hours after the sudden storm commencement. For the analysis we used three-dimensional test-particle simulations of global evolution of the outer belt in the Tsyganenko-Sitnov (TS07D) magnetic field model with the inductive electric field. The comparison of the simulation results with electron measurements from the MagEIS experiment shows that the magnetopause losses in the model accounts for most of the observed depletion. The individual electron motion the process is non-adiabatic; the third invariant is violated by global variations of the inner magnetospheric fields caused by the magnetopause compressions and the buildup of ring current, while the second invariant is violated at drift orbit bifurcations. The analysis shows that the observed deep depletion of radiation belt intensities is enabled by the change in the global configuration of magnetic

  3. Deterministic methods for the relativistic Vlasov-Maxwell equations and the Van Allen belts dynamics; Methodes deterministes de resolution des equations de Vlasov-Maxwell relativistes en vue du calcul de la dynamique des ceintures de Van Allen

    Energy Technology Data Exchange (ETDEWEB)

    Le Bourdiec, S

    2007-03-15

    Artificial satellites operate in an hostile radiation environment, the Van Allen radiation belts, which partly condition their reliability and their lifespan. In order to protect them, it is necessary to characterize the dynamics of the energetic electrons trapped in these radiation belts. This dynamics is essentially determined by the interactions between the energetic electrons and the existing electromagnetic waves. This work consisted in designing a numerical scheme to solve the equations modelling these interactions: the relativistic Vlasov-Maxwell system of equations. Our choice was directed towards methods of direct integration. We propose three new spectral methods for the momentum discretization: a Galerkin method and two collocation methods. All of them are based on scaled Hermite functions. The scaling factor is chosen in order to obtain the proper velocity resolution. We present in this thesis the discretization of the one-dimensional Vlasov-Poisson system and the numerical results obtained. Then we study the possible extensions of the methods to the complete relativistic problem. In order to reduce the computing time, parallelization and optimization of the algorithms were carried out. Finally, we present 1Dx-3Dv (mono-dimensional for x and three-dimensional for velocity) computations of Weibel and whistler instabilities with one or two electrons species. (author)

  4. TERSat: Trapped Energetic Radiation Satellite

    OpenAIRE

    Clements, Emily; Alvisio, Bruno; Babuscia, Alessandra; Casas, Zachary; Coffee, Brian; Giblin, Sydney; Hallock, Laura; Kingsbury, Ryan; Leaman, Michael; Lynch, Naomi; O'Connor, Michael; Qian, Elizabeth; Schmidt, Frank; de Soria-Santacruz, Maria; Sotomayor, Lionel

    2012-01-01

    Radiation damage caused by interactions with high-energy particles in the Van Allen Radiation Belts is a leading cause of component failures for satellites in low and medium Earth orbits (LEO, MEO). Very Low Frequency (VLF) electromagnetic waves have been shown to couple energy to high energy radiation belt particles and change their properties. For example, data from the IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) satellite suggest that the gap between the inner ...

  5. Artificial Economy

    Directory of Open Access Journals (Sweden)

    Alexandru JIVAN

    2011-08-01

    Full Text Available This paper proposes to eliminate, a routine in the economic thinking, claimed to be responsible for the negative essence of economic developments, from the point of view, of the ecological implications (employment in the planetary ecosystem. The methodological foundations start from the natural origins of the functionality of the human economic society according to the originary physiocrat liberalism, and from specific natural characteristics of the humankind. This paper begins with a comment-analysis of the difference between natural and artificial within the economy, and then explains some of the most serious diversions from the natural essence of economic liberalism. It shall be explained the original (heterodox interpretation of the Classical political economy (economics, by making calls to the Romanian economic thinking from aggravating past century. Highlighting the destructive impact of the economy - which, under the invoked doctrines, we call unnatural - allows an intuitive presentation of a logical extension of Marshall's market price, based on previous research. Besides the doctrinal arguments presented, the economic realities inventoried along the way (major deficiencies and effects, determined demonstrate the validity of the hypothesis of the unnatural character and therefore necessarily to be corrected, of the concept and of the mechanisms of the current economy.The results of this paper consist of original heterodox methodspresented, intuitive or developed that can be found conclusively within the key proposals for education and regulation.

  6. Modeling of the outer electron belt during magnetic storms

    International Nuclear Information System (INIS)

    The flux dropout of relativistic electrons in the earth's outer radiation belt, during the main phase of the 26 March 1995 magnetic storm is examined. Outer belt measurements by the Radiation Environment Monitor, REM aboard the STRV-1b satellite are presented to characterize this dropout. In order to simulate the dynamics of the electron belt during the storm main phase a particle tracing code was developed which allows to trace the trajectories of equatorially mirroring electrons in a dynamic magnetospheric electromagnetic field. Two simulations were performed in a non-stationary magnetic field, one taking only the induced electric field into account (fully adiabatic motion), and one with an additional non-stationary convection electric field. The simulations show, that adiabatic deceleration can produce the observed count rate decrease and also the observed inward motion of the count rate peak. The convection electric field causes diffusion, which can take particles from low L values out to the magnetopause and contribute to an additional loss of particles, which is suggested by the observations

  7. The use of solar simulation systems for producing artificial global radiation for the purpose of determining the heat load of rooms

    Science.gov (United States)

    Kalt, A. C.

    1975-01-01

    Certain climatic tests which require solar and sky radiation were carried out in the laboratory by using simulated global radiation. The advantages of such a method of measurement and the possibilities and limitations resulting from the simulation of global radiation are described. Experiments concerning the thermal load in rooms were conducted in order to test the procedure. In particular, the heat gain through a window with sunshade is discussed, a venetian blind between the panes of a double-glazed window being used in most cases.

  8. Synchronous and Cogged Fan Belt Performance Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Cutler, D.; Dean, J.; Acosta, J.

    2014-02-01

    The GSA Regional GPG Team commissioned the National Renewable Energy Laboratory (NREL) to perform monitoring of cogged V-belts and synchronous belts on both a constant volume and a variable air volume fan at the Byron G. Rodgers Federal Building and U.S. Courthouse in Denver, Colorado. These motor/fan combinations were tested with their original, standard V-belts (appropriately tensioned by an operation and maintenance professional) to obtain a baseline for standard operation. They were then switched to the cogged V-belts, and finally to synchronous belts. The power consumption by the motor was normalized for both fan speed and air density changes. This was necessary to ensure that the power readings were not influenced by a change in rotational fan speed or by the power required to push denser air. Finally, energy savings and operation and maintenance savings were compiled into an economic life-cycle cost analysis of the different belt options.

  9. Belt technology stretches conveyors' coverage

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-15

    With China the leading growth engine in the conveyor market, leading belt manufacturers are establishing local manufacturing plants to boost their presence. Fenner is planning to almost triple production capacity over the next three years, with a third of its investment in China. Shanxi-Phoenix Conveyor Belt Systems is a joint venture between Phoenix Conveyor Belt Systems GmbH, now part of ContiTech Ag, and its Chinese partners Lu An Mining Group Co. Ltd. and Jingcheng Anthracite Group Co. Ltd. It manufacturers steel cable belts, PVC and multi-ply belts for coal mines and power plants. Recent belt designs by FennerEurope and Metso Minerals are reported. 2 photos.

  10. Radiation

    International Nuclear Information System (INIS)

    The basic facts about radiation are explained, along with some simple and natural ways of combating its ill-effects, based on ancient healing wisdom as well as the latest biochemical and technological research. Details are also given of the diet that saved thousands of lives in Nagasaki after the Atomic bomb attack. Special comment is made on the use of radiation for food processing. (U.K.)

  11. NONLINEAR DYNAMIC BEHAVIOR OF VISCOELATIC TRANSMISSION BELT

    Institute of Scientific and Technical Information of China (English)

    Li Yinghui; Gao Qing; Jian Kailin; Yin Xuegang

    2003-01-01

    The nonlinear dynamic responses of viscoelastic axially transmission belts are investigated and the Kelvin viscoelastic differential constitutive model is employed to characterize the material property of belts. The generalized equation of motion is obtained for a viscoelatic axially transmission belts with geometric nonlinearity first, and then is reduced to be a set of second-order nonlinear ordinary differential equations by applying Galerkin's method. Finally, the effects of viscosity parameter and elastic parameter and the moving velocity of the belts on the transient responses are investigated by the research of digital simulation.

  12. Radiation

    International Nuclear Information System (INIS)

    Exposure to solar and ionizing radiation increases the risk for cancer in humans. Some 5% of solar radiation is within the ultraviolet spectrum and may cause both malignant melanoma and non-melanocytic skin cancer; the latter is regarded as a benign disease and is accordingly not included in our estimation of avoidable cancers. Under the assumption that the rate of occurrence of malignant melanoma of the buttocks of both men and women and of the scalp of women would apply to all parts of the body in people completely unexposed to solar radiation, it was estimated that approximately 95% of all malignant melanomas arising in the Nordic populations around the year 2000 will be due to exposure to natural ultraviolet radiation, equivalent to an annual number of about 4700 cases, with 2100 in men and 2600 in women, or some 4% of all cancers notified. Exposure to ionizing radiation in the Nordic countries occurs at an average effective dose per capita per year of about 3 mSv (Iceland, 1.1 mSv) from natural sources, and about 1 mSv from man-made sources. While the natural sources are primarily radon in indoor air, natural radionuclides in food, cosmic radiation and gamma radiation from soil and building materials, the man-made sources are dominated by the diagnostic and therapeutic use of ionizing radiation. On the basis of measured levels of radon in Nordic dwellings and associated risk estimates for lung cancer derived from well-conducted epidemiological studies, we estimated that about 180 cases of lung cancer (1% of all lung cancer cases) per year could be avoided in the Nordic countries around the year 2000 if indoor exposure to radon were eliminated, and that an additional 720 cases (6%) could be avoided annually if either radon or tobacco smoking were eliminated. Similarly, it was estimated that the exposure of the Nordic populations to natural sources of ionizing radiation other than radon and to medical sources will each give rise to an annual total of 2120

  13. Brusque belt: a monocyclic evolution ?

    International Nuclear Information System (INIS)

    This paper discusses the radiometric data for the Brusque Belt (SC) where Rb-Sr isochrons, U-Pb in zircons, K-Ar in minerals and whole rock Sm-Nd model ages are available. The analysis of these results reveals two main groups, without intermediate values. The first, 500 to 800Ma., is related to magmatic and metamorphic ages and the second, 1600-2000Ma begin with the (probably) sedimentation age. A monociclic evolution is proposed, but with uncertanties in the age of the first metamorphic phase. (author)

  14. Sensitivity of winter phytoplankton communities from Andean lakes to artificial ultraviolet-B radiation Sensibilidad de comunidades fitoplanctónicas invernales de lagos andinos a la radiación ultravioleta-B artificial

    Directory of Open Access Journals (Sweden)

    E. WALTER HELBLING

    2001-06-01

    Full Text Available During July of 1999 sampling was carried out in five Andean lakes to determine the sensitivity of winter phytoplankton communities to ultraviolet-B radiation (UV-B, 280-320 nm. The studied lakes, Moreno, El Trébol, Nahuel Huapi, Gutiérrez, and Morenito, located in the Patagonia region (41° S, 71° W, 800 m of altitude, had attenuation coefficients for UV-B that ranged from 0.36 m-1 (Lake Moreno to 2.8 m-1 (Lake Morenito. The samples were inoculated with labeled carbon (NaH14CO3 and incubated in an illuminated chamber (UV-B = 0.35 W m-2, UV-A [320-400 nm] = 1.1 W m-2, and PAR [400-700 nm] = 10.8 W m-2 at 10 °C. The phytoplankton cells were exposed to UV radiation (280-400 nm + PAR (quartz tubes, and to UV-A + PAR (quartz tubes covered with Mylar-D. The total duration of the experiments was 4 h and two samples were taken from each treatment every hour. In lakes Moreno, El Trébol, Nahuel Huapi and Gutiérrez, the photosynthetic inhibition increased linearly with UV-B doses, while in Lake Morenito just a slight relationship was observed. After receiving a dose of 1.25 kJ m-2 (UV-B, phytoplankton from Lake Morenito had the highest cumulative photosynthetic inhibition (44 %, whereas in Lakes Moreno, El Trébol, Nahuel Huapi and Gutiérrez the inhibition was of 22, 11, 5, and 1 %, respectively. However, at the end of incubation period and after receiving doses of 5 kJ m-2, the most inhibited phytoplankton cells were from Lake Moreno (70 % and the most resistant (27 % was that from Lake Gutiérrez. The kinetics of inhibition was different in each lake, and transparent lakes, with higher proportion of large cells, had higher inhibition rates. The results suggest that an increase in UV-B radiation (e.g., produced by a decrease in stratospheric ozone would have a greater impact on microplankton from clear lakes, while pico- and nanoplankton from less transparent lakes will be less affectedDurante julio de 1999 se realizaron muestreos en cinco lagos

  15. Progress on the artificial rearing of the army worm, Spodoptera (Laphygma) exigua Hb. and radiation sterilization in the male of this species

    International Nuclear Information System (INIS)

    The army worm, Spodoptera exigua Hb. was reared for 6 more generations in an artificial medium containing Mung bean as a major component. By improving the rearing temperature and humidity conditions, better rearing results were obtained. The average percentage of development from eggs to pupae, from eggs to adults, and from pupae to adults was 41.7+-4.93, 38.44+-6.32 and 88.1+-1.48 respectively. The pupal weight was also calculated. In sterilization studies, the 3-day-old male pupae were subjected to gamma rays at 0, 5 and 10 krads. Upon emerging into adults, they were mated with non-irradiated female moths. Male moths emerged from pupae subjected to 10 krads of gamma rays could significantly induce infertility in eggs deposited

  16. Apparatus for heat treating plastic belts

    Science.gov (United States)

    Topits, A., Jr.

    1975-01-01

    Apparatus performs programed rotating, stretching/shrinking and heat treatment necessary to fabrication of high-performance plastic belts. Belts can be treated in lengths varying from 7 to 48 in., in widths up to 1 in., and in thicknesses up to approximately 0.003 in.

  17. Parameters affecting seat belt use in Greece.

    Science.gov (United States)

    Yannis, G; Laiou, A; Vardaki, S; Papadimitriou, E; Dragomanovits, A; Kanellaidis, G

    2011-09-01

    The objective of this research is the exploration of seat belt use in Greece and particularly the identification of the parameters affecting seat belt use in Greece. A national field survey was conducted for the analytical recording of seat belt use. A binary logistic regression model was developed, and the impact of each parameter on seat belt use in Greece was quantified. Parameters included in the model concern characteristics of car occupants (gender, age and position in the car), the type of the car and the type of the road network. The data collection revealed that in Greece, the non-use of seat belt on the urban road network was higher than on the national and rural road network and young and older men use seat belts the least. The developed model showed that travelling on a national road is negative for not wearing the seat belt. Finally, the variable with the highest impact on not wearing a seat belt is being a passenger on the back seats. PMID:21452095

  18. Understanding Quaternions and the Dirac Belt Trick

    Science.gov (United States)

    Staley, Mark

    2010-01-01

    The Dirac belt trick is often employed in physics classrooms to show that a 2n rotation is not topologically equivalent to the absence of rotation whereas a 4n rotation is, mirroring a key property of quaternions and their isomorphic cousins, spinors. The belt trick can leave the student wondering if a real understanding of quaternions and spinors…

  19. Situational characteristics of safety belt use.

    Science.gov (United States)

    Fockler, S K; Cooper, P J

    1990-04-01

    Past research concerning the use and nonuse of safety belts has tended to stereotype users and nonusers as distinct entities on the basis of a single observed situation. The thought processes underlying the reasons given by drivers for using or not using seat belts have not been explored. The purpose of this study was to observe belt use by a group of drivers and describe factors contributing to their use or nonuse as defined by the drivers themselves. In-depth interviews were undertaken with 239 drivers whose safety belt wearing behavior was observed in specific city or highway driving locations. Vehicle license numbers, gender, and age group of selected drivers were used to retrieve driver records and insurance policy data. Open-ended questions were asked concerning their reasons for use or nonuse and their attitudes towards safety belts and other types of traffic safety countermeasures. Driver attitudes, characteristics, and records were compared between observed safety belt user and nonuser groups to validate variables predicting use or nonuse. Respondents' descriptions of the social and personal context of their choice to use or not use safety belts provide a broader view of seat belt wearing that suggests implications for planning future enforcement and education programs. PMID:2331287

  20. Future aerosol reductions and widening of the northern tropical belt

    Science.gov (United States)

    Allen, Robert J.; Ajoku, Osinachi

    2016-06-01

    Observations show that the tropical belt has widened over the past few decades, a phenomenon associated with poleward migration of subtropical dry zones and large-scale atmospheric circulation. Although part of this signal is related to natural climate variability, studies have identified an externally forced contribution primarily associated with greenhouse gases (GHGs) and stratospheric ozone loss. Here we show that the increase in aerosols over the twentieth century has led to contraction of the northern tropical belt, thereby offsetting part of the widening associated with the increase in GHGs. Over the 21st century, however, when aerosol emissions are projected to decrease, the effects of aerosols and GHGs reinforce one another, both contributing to widening of the northern tropical belt. Models that have larger aerosol forcing, by including aerosol indirect effects on cloud albedo and lifetime, yield significantly larger Northern Hemisphere (NH) tropical widening than models with direct aerosol effects only. More targeted simulations show that future reductions in aerosols can drive NH tropical widening as large as greenhouse gases, and idealized simulations show the importance of NH midlatitude aerosol forcing. Mechanistically, the 21st century reduction in aerosols peaks near 40°N, which results in a corresponding maximum increase in surface solar radiation, NH midlatitude tropospheric warming amplification, and a poleward shift in the latitude of maximum baroclinicity, implying a corresponding shift in atmospheric circulation. If models with aerosol indirect effects better represent the real world, then future aerosol changes are likely to be an important -- if not dominant -- driver of NH tropical belt widening.

  1. Artificial Inteligence and Law

    OpenAIRE

    Fuková, Kateřina

    2012-01-01

    Submitted diploma work Artificial Intelligence and Law deals with the rule of law and its position in the process of new advanced technologies in computer cybernetics and further scientific disciplines related with artificial intelligence and its creation. The first part of the work introduces the history of the first imagines about artificial intelligence and concerns with its birth. This chapter presents main theoretical knowledge and hypotheses defined artificial intelligence and progre...

  2. Artificial Skin in Robotics

    OpenAIRE

    Strohmayr, Michael

    2012-01-01

    Artificial Skin - A comprehensive interface for system-environment interaction - This thesis investigates a multifunctional artificial skin as touch sensitive whole-body cover for robotic systems. To further the evolution from tactile sensors to an implementable artificial skin a general concept for the design process is derived. A standard test procedure is proposed to evaluate the performance. The artificial skin contributes to a safe and intuitive physical human robot interaction.

  3. The Gould's Belt distance survey

    CERN Document Server

    Loinard, L; Torres, R M; Dzib, S; Rodriguez, L F; Boden, A F

    2011-01-01

    Very Long Baseline Interferometry (VLBI) observations can provide the position of compact radio sources with an accuracy of order 50 micro-arcseconds. This is sufficient to measure the trigonometric parallax and proper motions of any object within 500 pc of the Sun to better than a few percent. Because they are magnetically active, young stars are often associated with compact radio emission detectable using VLBI techniques. Here we will show how VLBI observations have already constrained the distance to the most often studied nearby regions of star-formation (Taurus, Ophiuchus, Orion, etc.) and have started to provide information on their internal structure and kinematics. We will then briefly describe a large project (called The Gould's Belt Distance Survey) designed to provide a detailed view of star-formation in the Solar neighborhood using VLBI observations.

  4. Application of cool wan flow control weight scale design on belt conveyor

    International Nuclear Information System (INIS)

    Control of the coal mass flow on the belt conveyor at coal handling unit PLTU Suralaya has been designed by using weight scale of gamma absorption technique where accuracy for the measurement of weight scale system is 0,5% to 0,1%. The absorption gamma radiation will be measured by scintillation or ion chamber detector

  5. Radiation and People

    Science.gov (United States)

    Freilich, Florence G.

    1970-01-01

    Describes the development of radiation as a tool of medicine. Includes topics on history of radiation, electromagnetic spectrum, X-ray tubes, high energy machines, radioactive sources, artificial radioactivity, radioactive scanning, units, present radiation background, and effect of radiation on living tissue. (DS)

  6. Strategy for replacing conveyor belts in complex haulage systems

    Energy Technology Data Exchange (ETDEWEB)

    Gladysiewicz, L.; Jurdziak, L.; Masella, J.

    1986-01-01

    Discusses service life and reliability of conveyor belts used for mine haulage in brown coal surface mining and a method for optimizing belt service life. Based on analysis of operation of 900-1,200 m long belt conveyors in the Konin surface mine, failure rates and factors that influence belt reliability were determined. Effects of joints, length of belt sections and service life of each belt section were analyzed. Formulae for determining the optimum time interval for replacing belt sections on a long belt conveyor were derived. The formulae consider cost of new belt sections, replacement cost and haulage losses associated with possible belt failure caused by excessive belt service life. The optimization procedure has been successfully tested at the Turow surface mine and power plant. 4 refs.

  7. Effects of gamma radiation and electron beam on samples of the Brazil nuts artificially inoculated with Aspergillus flavus; Efeitos da radiacao gama e feixe de eletrons sobre amostras de castanhas-do-Brasil inoculadas artificialmente com Aspergillus flavus

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Ednei Assuncao Antunes

    2012-07-01

    The high level of contamination by aflatoxin produced by fungi in lots of Brazil nuts and the strict control by importing countries in relation to the levels of toxins in food, European Union countries decided in 2003 by the return of these lots products from Brazil. Despite the economic loss represented by contamination by toxigenic fungi in Brazil nuts, a major product of extractive Northern of Brazil, studies are still preliminary as the control of contamination aflatoxigenic fungal using methods such as gamma radiation (G.R) and mainly, electron beam (E.B). These facts motivated this research, which aimed to evaluate the effects of gamma radiation and application of electron beam in samples of Brazil nut artificially inoculated with Aspergillus flavus. This goal, we were studied 50 samples of the Brazil nut previously inoculated with spores of A. flavus and subsequently incubated at 30 °C in relative humidity controlled at 93%. After incubation, period of 15 days, the average water activity of the samples was 0.80, the samples were divided into 5 groups that received the following doses of radiation: control (0 kGy), 5 and 10 kGy 5 E.B and G.R. The mycobiota was performed by serial dilution, plated on surface using potato dextrose agar. The results demonstrated that treatment with E.B using a dose of 5 kGy and 10 kGy resulted in reduced growth of A. flavus in 74% (37/50) and 94% (47/50) of samples. The samples treated with G.R at the dose of 5 kGy and 10 kGy no fungal growth occurred in 92% (46/50) 100% (50/50) of. The study of aflatoxins showed that doses of E.B of 5 kGy and 10 kGy reduced levels of AFB1 at 53.32% and 65.66% respectively. The application of gamma rays at doses of 5 and 10 kGy reduced levels of toxins in 70.61% and 84.15% respectively. This result may be attributed to higher penetrability of gamma radiation. Sensory analysis showed greater acceptance of the judges for the samples irradiated with E.B and G.R at the dose of 10 kGy. We concluded

  8. Combining Heavy Ion Radiation and Artificial MicroRNAs to Target the Homologous Recombination Repair Gene Efficiently Kills Human Tumor Cells

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Zhiming [Department of Neurosurgery, Provincial Hospital Affiliated to Shandong University, Shandong University, Jinan (China); Department of Radiation Oncology, School of Medicine, Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Wang Ping; Wang Hongyan; Zhang Xiangming [Department of Radiation Oncology, School of Medicine, Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Wang Minli [Division of Life Sciences, Universities Space Research Association, Houston, Texas (United States); Cucinotta, Francis A. [National Aeronautics and Space Administration, Lyndon B. Johnson Space Center, Houston, Texas (United States); Wang Ya, E-mail: ywang94@emory.edu [Department of Radiation Oncology, School of Medicine, Winship Cancer Institute, Emory University, Atlanta, Georgia (United States)

    2013-02-01

    Purpose: Previously, we demonstrated that heavy ions kill more cells at the same dose than X-rays because DNA-clustered lesions produced by heavy ions affect nonhomologous end-joining (NHEJ) repair but not homologous recombination repair (HRR). We have also shown that our designed artificial microRNAs (amiRs) could efficiently target XRCC4 (an essential factor for NHEJ) or XRCC2 (an essential factor for HRR) and sensitize human tumor cells to X-rays. Based on these data, we were interested in testing the hypothesis that combining heavy ions and amiRs to target HRR but not NHEJ should more efficiently kill human tumor cells. Methods and Materials: Human tumor cell lines (U87MG, a brain tumor cell line, and A549, a lung cancer cell line) and their counterparts, overexpressed with amiR to target XRCC2, XRCC4 or both, were used in this study. Survival sensitivities were examined using a clonogenic assay after these cells were exposed to X-rays or heavy ions. In addition, these cell lines were subcutaneously injected into nude mice to form xenografts and the tumor size was compared after the tumor areas were exposed to X-rays or heavy ions. Results: Although targeting either XRCC4 (NHEJ factor) or XRCC2 (HRR factor) sensitized the human tumor cells to X-rays, in vitro and the xenograft animal model, targeting only XRCC2 but not XRCC4 sensitized the human tumor cells to heavy ions in vitro and in the xenograft animal model. Conclusions: Combining heavy ions with targeting the HRR pathway, but not the NHEJ pathway, could significantly improve the efficiency of tumor cell death.

  9. Combining Heavy Ion Radiation and Artificial MicroRNAs to Target the Homologous Recombination Repair Gene Efficiently Kills Human Tumor Cells

    International Nuclear Information System (INIS)

    Purpose: Previously, we demonstrated that heavy ions kill more cells at the same dose than X-rays because DNA-clustered lesions produced by heavy ions affect nonhomologous end-joining (NHEJ) repair but not homologous recombination repair (HRR). We have also shown that our designed artificial microRNAs (amiRs) could efficiently target XRCC4 (an essential factor for NHEJ) or XRCC2 (an essential factor for HRR) and sensitize human tumor cells to X-rays. Based on these data, we were interested in testing the hypothesis that combining heavy ions and amiRs to target HRR but not NHEJ should more efficiently kill human tumor cells. Methods and Materials: Human tumor cell lines (U87MG, a brain tumor cell line, and A549, a lung cancer cell line) and their counterparts, overexpressed with amiR to target XRCC2, XRCC4 or both, were used in this study. Survival sensitivities were examined using a clonogenic assay after these cells were exposed to X-rays or heavy ions. In addition, these cell lines were subcutaneously injected into nude mice to form xenografts and the tumor size was compared after the tumor areas were exposed to X-rays or heavy ions. Results: Although targeting either XRCC4 (NHEJ factor) or XRCC2 (HRR factor) sensitized the human tumor cells to X-rays, in vitro and the xenograft animal model, targeting only XRCC2 but not XRCC4 sensitized the human tumor cells to heavy ions in vitro and in the xenograft animal model. Conclusions: Combining heavy ions with targeting the HRR pathway, but not the NHEJ pathway, could significantly improve the efficiency of tumor cell death.

  10. Seat belt use law in developing countries

    Institute of Scientific and Technical Information of China (English)

    SangWanLee

    1999-01-01

    Objective:To highlight the way to successful implementation of mandantory seat belt use law in developing countries particulary where have significant increase in number or cars and subsequent increase in car occupant casualties.Methods:Literatures concerning seat belt use were reviewed and experiences of the world.Satisfactory or not,investigated.It summed up general aspects of seat belt use as well as benefits,attitude toward legislation and measures to enhance the usage.Results:Seat belt use has been proven and stood time tested as the most effective means to protect car occupants from road crash injuries.It appears to be arduous to achieve the golal of seat belt use law in developing countries. but possible via strategies appropriately leading to legislation and promotion of the belt usage.Conclusions:It is prime necessity for the government authorities to recognize the importance of seat belt use.There needs an organizational structure composed of relevant professional from both private and government sectors which is able to carry out every steps toward successful legislation and implementation:education,publicity,enforcement,evaluation and dissemination of the law's benefits.

  11. DYNAMIC RESPONSES OF VISCOELASTIC AXIALLY MOVING BELT

    Institute of Scientific and Technical Information of China (English)

    李映辉; 高庆; 蹇开林; 殷学纲

    2003-01-01

    Based on the Kelvin viscoelastic differential constitutive law and the motion equation of the axially moving belt, the nonlinear dynamic model of the viscoelastic axial moving belt was established. And then it was reduced to be a linear differential system which the analytical solutions with a constant transport velocity and with a harmonically varying transport velocity were obtained by applying Lie group transformations. According to the nonlinear dynamic model, the effects of material parameters and the steady-state velocity and the perturbed axial velocity of the belt on the dynamic responses of the belts were investigated by the research of digital simulation. The result shows: 1 ) The nonlinear vibration frequency of the belt will become small when the relocity of the belt increases. 2 ) Increasing the value of viscosity or decreasing the value of elasticity leads to a deceasing in vibration frequencies. 3 ) The most effects of the transverse amplitudes come from the frequency of the perturbed velocity when the belt moves with harmonic velocity.

  12. Radiation Hydrodynamics

    Science.gov (United States)

    Mihalas, Dimitri

    Basic Radiation Theory Specific Intensity Photon Number Density Photon Distribution Function Mean Intensity Radiation Energy Density Radiation Energy Flux Radiation Momentum Density Radiation Stress Tensor (Radiation Pressure Tensor) Thermal Radiation Thermodynamics of Thermal Radiation and a Perfect Gas The Transfer Equation Absorption, Emission, and Scattering The Equation of Transfer Moments of the Transfer Equation Lorentz Transformation of the Transfer Equation Lorentz Transformation of the Photon 4-Momentum Lorentz Transformation of the Specific Intensity, Opacity, and - Emissivity Lorentz Transformation of the Radiation Stress Energy Tensor The Radiation 4-Force Density Vector Covariant Form of the Transfer Equation Inertial-Frame Equations of Radiation Hydrodynamics Inertial-Frame Radiation Equations Inertial-Frame Equations of Radiation Hydrodynamics Comoving-Frame Equation of Transfer Special Relativistic Derivation (D. Mihalas) Consistency Between Comoving-Frame and Inertial-Frame Equations Noninertial Frame Derivation (J. I. Castor) Analysis of O (v/c) Terms Lagrangian Equations of Radiation Hydrodynamics Momentum Equation Gas Energy Equation First Law of Thermodynamics for the Radiation Field First Law of Thermodynamics for the Radiating Fluid Mechanical Energy Equation Total Energy Equation Consistency of Different Forms of the Radiating-Fluid Energy - and Momentum Equations Consistency of Inertial-Frame and Comoving-Frame Radiation Energy - and Momentum Equations Radiation Diffusion Radiation Diffusion Nonequilibrium Diffusion The Problem of Flux Limiting Shock Propagation: Numerical Methods Acoustic Waves Numerical Stability Systems of Equations Implications of Shock Development Implications of Diffusive Energy Transport Illustrative Example Numerical Radiation Hydrodynamics Radiating Fluid Energy and Momentum Equations Computational Strategy Energy Conservation Formal Solution Multigroup Equations An Astrophysical Example Adaptive-Grid Radiation

  13. From transmission error measurement to Pulley-Belt slip determination in serpentine belt drives: influence of tensioner and belt characteristics

    OpenAIRE

    Manin, Lionel; Michon, Guilhem; Rémond, Didier; Dufour, Regis

    2007-01-01

    Serpentine belt drives are often used in front end accessory drive of automotive engine. The accessories resistant torques are getting higher within new technological innovations as stater-alternator, and belt transmissions are always asked for higher capacity. Two kind of tensioners are used to maintain minimum tension that insure power transmission and minimize slip: dry friction or hydraulic tensioners. An experimental device and a specific transmission error measurement method have been u...

  14. 电离层人工调制激发的下行ELF/VLF波辐射%The downward ELF/VLF waves radiation excited by ionospheric artificial modulation

    Institute of Scientific and Technical Information of China (English)

    常珊珊; 赵正予; 汪枫

    2011-01-01

    By heating the ionosphere with large ELF/VLF-modulated HF wave, a virtual antenna is produced in the ionosphere, which is an effective means to radiate ELF/VLF waves. This paper uses the modulated-heating models of Wang Feng (2009) to calculate the strength of the LF radiation source produced by HF heating, uses full-wave model to analyze attenuation and reflection of the LF wave transmitting downward, and with HAARP experiment parameter, simulates magnetic field of the LF signals on the sea, which is in PT order, according with the experimental data.%通过大功率ELF/VLF调幅高频波对电离层进行加热,形成电离层虚拟天线,可以作为发射ELF/VLF波的一种有效手段.本文使用汪枫(2009)的调制加热模型,计算高频加热电离层产生的低频辐射源强度,采用全波解算法分析辐射的低频波向下传播过程中的衰减和反射问题,并采用HAARP实验参数,模拟出在海面上接收到的低频信号强度为PT量级,与实验数据一致.模拟结果表明,加热泵波功率、低频调制波频率、以及加热纬度位置是影响ELF/VLF波辐射和传播的三个主要因素.

  15. The recognition of extraterrestrial artificial signals

    International Nuclear Information System (INIS)

    Considerations in the design of receivers for the detection and recognition of artificial microwave signals of extraterrestrial origin are discussed. Following a review of the objectives of SETI and the probable reception and detection characteristics of extraterrestrial signals, means for the improvement of the sensitivity, signal-to-noise ratios and on-line data processing capabilities of SETI receivers are indicated. The characteristics of the signals likely to be present at the output of an ultra-low-noise microwave receiver are then examined, including the system background noise, terrestrial radiations, astrophysical radiations, accidental artificial radiations of terrestrial origin, and intentional radiations produced by humans and by extraterrestrial intelligence. The classes of extraterrestrial signals likely to be detected, beacons and leakage signals, are considered, and options in the specification of gating and thresholding for a high-spectral resolution, high-time-resolution signal discriminator are indicated. Possible tests for the nonhuman origin of a received signal are also pointed out

  16. Simulation of engine auxiliary drive V-belt slip motion. Part 1. Development of belt slip model; Engine hoki V belt slip kyodo no simulation. 1. Belt slip model no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kurisu, T. [Mazda Motor Corp., Hiroshima (Japan)

    1997-10-01

    V-belts are widely used for driving auxiliary components of an engine. Inadequet design of such belt system sometimes results in troubles such as belt squeak, side rubber separation and/or bottom rubber crack. However, there has been no design tools which can predict belt slip quantitatively. The author developed a motion simulation program of Auxiliary Drive V-Belt System considering belt slip. The program showed good prediction accuracy for belt slip motion. This paper describes the simulation model. 1 ref., 12 figs.

  17. The Compositional Structure of the Asteroid Belt

    CERN Document Server

    DeMeo, Francesca E; Walsh, Kevin J; Chapman, Clark R; Binzel, Richard P

    2015-01-01

    The past decade has brought major improvements in large-scale asteroid discovery and characterization with over half a million known asteroids and over 100,000 with some measurement of physical characterization. This explosion of data has allowed us to create a new global picture of the Main Asteroid Belt. Put in context with meteorite measurements and dynamical models, a new and more complete picture of Solar System evolution has emerged. The question has changed from "What was the original compositional gradient of the Asteroid Belt?" to "What was the original compositional gradient of small bodies across the entire Solar System?" No longer is the leading theory that two belts of planetesimals are primordial, but instead those belts were formed and sculpted through evolutionary processes after Solar System formation. This article reviews the advancements on the fronts of asteroid compositional characterization, meteorite measurements, and dynamical theories in the context of the heliocentric distribution of...

  18. Handbook Timing Belts Principles, Calculations, Applications

    CERN Document Server

    Perneder, Raimund

    2012-01-01

    Timing belts offer a broad range of innovative drivetrain solutions; they allow low-backlash operation in robot systems, they are widely used in automated processes and industrial handling involving highly dynamic start-up loads, they are low-maintenance solutions for continuous operation applications, and they can guarantee exact positioning at high operating speeds. Based on his years of professional experience, the author has developed concise guidelines for the dimensioning of timing belt drives and presents proven examples from the fields of power transmission, transport and linear transfer technology. He offers definitive support for dealing with and compensating for adverse operating conditions and belt damage, as well as advice on drive optimization and guidelines for the design of drivetrain details and supporting systems. All market-standard timing belts are listed as brand neutral. Readers will discover an extensive bibliography with information on the various manufacturers and their websites. This...

  19. Dynamics of the outer asteroid belt

    International Nuclear Information System (INIS)

    This paper considers the issue of modeling the dynamics of the outer asteroid belt. The hypotheses and assumptions of an asteroid-belt model are discussed together with their problems, of which gaps at some mean-motion resonances with Jupiter and the depletion of the outer belt are the most outstanding ones. Particular attention is given to the theory of the 2:1 gap, the depletion problem, and the mechanisms of dynamical protection against strong perturbations by Jupiter. It is suggested that the observed asteroids must have gone through a process of natural selection as a result of which all objects in unprotected orbits have been ejected from the system. Spectral observations show a reddening in spectral slope with increasing heliocentric distance; it is proposed that this is an evidence that outer-belt asteroids might be primordial objects. 41 refs

  20. Artificial Atoms: from Quantum Physics to Applications

    International Nuclear Information System (INIS)

    The primary objective of this workshop is to survey the most recent advances of technologies enabling single atom- and artificial atom-based devices. These include the assembly of artificial molecular structures with magnetic dipole and optical interactions between engineered atoms embedded in solid-state lattices. The ability to control single atoms in diamond or similar solids under ambient operating conditions opens new perspectives for technologies based on nanoelectronics and nanophotonics. The scope of the workshop is extended towards the physics of strong coupling between atoms and radiation field modes. Beyond the traditional atom-cavity systems, artificial dipoles coupled to microwave radiation in circuit quantum electrodynamics is considered. All these technologies mutually influence each other in developing novel devices for sensing at the quantum level and for quantum information processing.

  1. THE GOULD'S BELT DISTANCE SURVEY

    Directory of Open Access Journals (Sweden)

    L. Loinard

    2011-01-01

    Full Text Available Observaciones que utilizan la interferometría de muy larga línea de base (VLBI por sus siglas en ingl´es pueden proveer la posición de radiofuentes compactas con una precisión del orden de 50 micro-segundos de arco. Esto es suficiente para medir la paralaje trigonométrica y los movimientos propios de cualquier objeto localizado hasta 500 pc del Sol con una precisión mejor que unos porcientos. Por ser magnéticamente activas, las estrellas jóvenes a menudo emiten emisión radio compacta detectable usando técnicas VLBI. Aquí, mostraremos cómo observaciones VLBI ya han restringido la distancia a las regiones de formación estelar cercanas más frecuentemente estudiadas (Tauro, Ofiuco, Orión, etc. y han empezado a revelar su estructura y su cinemática interna. Luego, describiremos un gran proyecto (llamado The Gould's Belt Distance Survey diseñado para proveer una vista detallada de la formación estelar en la vecindad Solar, usando observaciones VLBI.

  2. Quo Vadis, Artificial Intelligence?

    OpenAIRE

    Alfons Schuster; Daniel Berrar; Naoyuki Sato

    2010-01-01

    Since its conception in the mid 1950s, artificial intelligence with its great ambition to understand and emulate intelligence in natural and artificial environments alike is now a truly multidisciplinary field that reaches out and is inspired by a great diversity of other fields. Rapid advances in research and technology in various fields have created environments into which artificial intelligence could embed itself naturally and comfortably. Neuroscience with its desire to understand nervou...

  3. Anticipatory Artificial Autopoiesis

    OpenAIRE

    DuBois, Daniel; Holmberg, Stig C.

    2010-01-01

    In examining relationships between autopoiesis and anticipation in artificial life (Alife) systems it is demonstrated that anticipation may increase efficiency and viability in artificial autopoietic living systems. This paper, firstly, gives a review of the Varela et al [1974] automata algorithm of an autopoietic living cell. Some problems in this algorithm must be corrected. Secondly, a new and original anticipatory artificial autopoiesis algorithm for automata is presented. ...

  4. Artificial cognition architectures

    CERN Document Server

    Crowder, James A; Friess, Shelli A

    2013-01-01

    The goal of this book is to establish the foundation, principles, theory, and concepts that are the backbone of real, autonomous Artificial Intelligence. Presented here are some basic human intelligence concepts framed for Artificial Intelligence systems. These include concepts like Metacognition and Metamemory, along with architectural constructs for Artificial Intelligence versions of human brain functions like the prefrontal cortex. Also presented are possible hardware and software architectures that lend themselves to learning, reasoning, and self-evolution

  5. Doped Colloidal Artificial Ice

    OpenAIRE

    Libal, A.; Reichhardt, C. J. Olson; Reichhardt, C.

    2015-01-01

    We examine square and kagome artificial spin ice for colloids confined in arrays of double-well traps. Unlike magnetic artificial spin ices, colloidal and vortex artificial spin ice realizations allow creation of doping sites through double occupation of individual traps. We find that doping square and kagome ice geometries produces opposite effects. For square ice, doping creates local excitations in the ground state configuration that produce a local melting effect as the temperature is rai...

  6. Inteligencia artificial en vehiculo

    OpenAIRE

    Amador Díaz, Pedro

    2012-01-01

    Desarrollo de un robot seguidor de líneas, en el que se implementan diversas soluciones de las áreas de sistemas embebidos e inteligencia artificial. Desenvolupament d'un robot seguidor de línies, en el qual s'implementen diverses solucions de les àrees de sistemes encastats i intel·ligència artificial. Follower robot development of lines, in which various solutions are implemented in the areas of artificial intelligence embedded systems.

  7. Assessment of natural and artificial radiation dose in the city urban area of Goiania, Goias, Brazil: results of Campinas - Centro and Sul regions

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Nivaldo C.; Dias, Danila C.S.; Guerrero, Eder T.Z.; Alberti, Heber L.C., E-mail: ncsilva@cnen.gov.br, E-mail: edertzg@cnen.gov.br, E-mail: heber@cnen.gov.br [Comissao Nacional de Energia Nuclear (LAPOC/CNEN), Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas; Santos, Eliane E.; Pimenta, Lucinei R.; Costa, Heliana F., E-mail: esantos@cnen.gov.br, E-mail: lucinei@cnen.gov.br, E-mail: heliana@cnen.gov.br [Centro Regional de Ciencias Nucleares do Centro-Oeste (CRCN-CO/CNEN-GO), Abadia de Goias, GO (Brazil)

    2011-07-01

    An assessment of external gamma dose was carried out in some urban areas in the city of Goiania - GO - Brazil, allowing to infer the contribution of this component to the average annual effective dose value for the population leaving in that region. The measurements were done using a vehicle with a mobile radioactivity measurement system, Thermo-Eberline FHT 1376, consisting of plastic scintillation detector and a Global Position System (GPS), which is able to collect gamma dose rate as well as the local spatial coordinates. These data, associated with those from national census, provided by Brazilian Institute of Geography and Statistic, were analyzed using the ArcGIS software, a well known Geographical Information System - GIS. As the main result, radiometric maps were produced, illustrating how effective dose values are distributed within the selected areas and also correlating the collective dose values for these populations. Around 57,000 geo referenced effective dose values were measured in the so-called Campinas-Centro and Sul Regions, which are two of the seven regions Goiania is divided in for administrative purposes. The dose rates ranging from 10.4 to 192.7 nSv/h with an average of 22.4 nSv/h, which means 0.20 mSv/year as the annual effective dose. This values are lower than the worldwide average effective dose value of 0.46 mSv/year for outdoor exposures from terrestrial radiation sources) and lower than the previous average values found in Brazil for the regions of Pocos de Caldas, Guarapari, Andradas and Caldas. Actually, the average value is comparable with those observed in the Ribeirao Preto - SP - Brazil City. (author)

  8. Seat belts, airbags and child protection devices. [previously: Seat belts and child restraint seats.

    NARCIS (Netherlands)

    2010-01-01

    In the Netherlands, the use of seat belts results in a yearly reduction of hundreds of fatalities. Seat belts reduce the risk of fatal injury by 37 to 48%, depending on the position in the car. At 50%, the effect of child protection devices is even slightly higher. When last measured (in 2010), 97%

  9. Analysis of stress distribution of timing belts by FEM; Yugen yosoho ni yoru timing belt oryoku kaiseki (belt code oryoku bunpu kaiseki hokoku)

    Energy Technology Data Exchange (ETDEWEB)

    Furukawa, Y.; Tomono, K.; Takahashi, H.; Uchida, T. [Honda R and D Co. Ltd., Tokyo (Japan)

    1997-10-01

    A model of the belt analyzed by-ABAQUS (: a general nonlinear finite element program) successfully confirmed the mechanism that generates the belt cord stress. A quite good agreement between experimental and computed results for the stress distribution of the belt cord. It is found that maximum stress of the cords occurs near the root of the tooth by calculation, where the belt cords break off. 3 refs., 9 figs.

  10. Artificial life and life artificialization in Tron

    Directory of Open Access Journals (Sweden)

    Carolina Dantas Figueiredo

    2012-12-01

    Full Text Available Cinema constantly shows the struggle between the men and artificial intelligences. Fiction, and more specifically fiction films, lends itself to explore possibilities asking “what if?”. “What if”, in this case, is related to the eventual rebellion of artificial intelligences, theme explored in the movies Tron (1982 and Tron Legacy (2010 trat portray the conflict between programs and users. The present paper examines these films, observing particularly the possibility programs empowering. Finally, is briefly mentioned the concept of cyborg as a possibility of response to human concerns.

  11. Artificial insemination in poultry

    Science.gov (United States)

    Artificial insemination is a relative simple yet powerful tool geneticists can employ for the propagation of economically important traits in livestock and poultry. In this chapter, we address the fundamental methods of the artificial insemination of poultry, including semen collection, semen evalu...

  12. The Compositions of Kuiper Belt Objects

    CERN Document Server

    Brown, Michael E

    2011-01-01

    Objects in the Kuiper belt are small and far away thus difficult to study in detail even with the best telescopes available at earth. For much of the early history of the Kuiper belt, studies of the compositions of these objects were relegated to collections of moderate quality spectral and photometric data that remained difficult to interpret. Much early effort was put into simple correlations of surface colors and identifications of spectral features, but it was difficult to connect the observations to a larger understanding of the region. The last decade, however, has seen a blossoming in our understanding of the compositions of objects in the Kuiper belt. This blossoming is a product of the discoveries of larger -- and thus easier to study -- objects, continued dedication to the collection of a now quite large collection of high quality photometric and spectroscopic observations, and continued work at the laboratory and theoretical level. Today we now know of many processes which affect the surface compos...

  13. Lubricants for Metal Belt Continuously Variable Transmissions

    Directory of Open Access Journals (Sweden)

    Keiichi Narita

    2014-02-01

    Full Text Available This paper reviews the effects of lubricant additives and base stock used in metal belt continuously variable transmissions (CVT fluids on the CVT transmission torque capacity. Additive formulation composed of phosphorus anti-wear agent, calcium detergent, and dispersant improved the friction coefficient between the metals. The analysis on the post-test surface suggests that the friction behavior strongly depends on the local morphology of the tribofilms derived from lubricant additives. Examining the effect of base stock on the torque capacity in actual belt CVTs revealed that SN (synthetic naphthene exhibited 10% higher torque capacity than that of PAO (polyalphaolefin. It is believed that the difference in the torque capacity is due to the difference in the oil-film shearing force generated by the relative sliding between the belt and pulley.

  14. A shell model for tyre belt vibrations

    Science.gov (United States)

    Lecomte, C.; Graham, W. R.; Dale, M.

    2010-05-01

    We present a new formulation for the prediction of tyre belt vibrations in the frequency range 0-500 Hz. Our representation includes the effects of belt width, curvature and anisotropy, and also explicitly models the tyre sidewalls. Many of the associated numerical parameters are fixed by physical considerations; the remainder require empirical input. A systematic and general approach to this problem is developed, and illustrated for the specific example of a Goodyear Wrangler tyre. The resulting predictions for the radial response to radial forcing show good correspondence with experiment up to 300 Hz, and satisfactory agreement up to 1 kHz.

  15. Artificial ecosystem selection.

    Science.gov (United States)

    Swenson, W; Wilson, D S; Elias, R

    2000-08-01

    Artificial selection has been practiced for centuries to shape the properties of individual organisms, providing Darwin with a powerful argument for his theory of natural selection. We show that the properties of whole ecosystems can also be shaped by artificial selection procedures. Ecosystems initiated in the laboratory vary phenotypically and a proportion of the variation is heritable, despite the fact that the ecosystems initially are composed of thousands of species and millions of individuals. Artificial ecosystem selection can be used for practical purposes, illustrates an important role for complex interactions in evolution, and challenges a widespread belief that selection is most effective at lower levels of the biological hierarchy. PMID:10890915

  16. Timing belts - development, milestones and innovations; Zahnriemen Entwicklungsmeilensteine und Innovationen

    Energy Technology Data Exchange (ETDEWEB)

    Schulte, H. [Contitech Power Transmission Group (Germany)

    2005-12-01

    Contitech has much contributed to improve the characteristics of timing belts until today. In this article Contitech introduces some current developments and shows the advantages of belts compared to chain drives. (orig.)

  17. Developing Creativity: Artificial Barriers in Artificial Intelligence

    OpenAIRE

    Jennings, Kyle E.

    2010-01-01

    The greatest rhetorical challenge to developers of creative artificial intelligence systems is convincingly arguing that their software is more than just an extension of their own creativity. This paper suggests that “creative autonomy,” which exists when a system not only evaluates creations on its own, but also changes its standards without explicit direction, is a necessary condition for making this argument. Rather than requiring that the system be hermetically sealed to avoid perceptions...

  18. Composite Microdiscs with a Magnetic Belt

    DEFF Research Database (Denmark)

    Knaapila, Matti; Høyer, Henrik; Helgesen, Geir

    2015-01-01

    We describe an emulsion-based preparation of patchy composite particles (diameter of 100-500 mu m) consisting of a disclike epoxy core and a belt of porous polystyrene particles (diameter of 30 mu m) with magnetite within the pores. Compared to the magnetically uniform polystyrene particles, the...

  19. Principles of artificial intelligence

    CERN Document Server

    Nilsson, Nils J

    1980-01-01

    A classic introduction to artificial intelligence intended to bridge the gap between theory and practice, Principles of Artificial Intelligence describes fundamental AI ideas that underlie applications such as natural language processing, automatic programming, robotics, machine vision, automatic theorem proving, and intelligent data retrieval. Rather than focusing on the subject matter of the applications, the book is organized around general computational concepts involving the kinds of data structures used, the types of operations performed on the data structures, and the properties of th

  20. Intelligence: Real or artificial?

    OpenAIRE

    Schlinger, Henry D

    1992-01-01

    Throughout the history of the artificial intelligence movement, researchers have strived to create computers that could simulate general human intelligence. This paper argues that workers in artificial intelligence have failed to achieve this goal because they adopted the wrong model of human behavior and intelligence, namely a cognitive essentialist model with origins in the traditional philosophies of natural intelligence. An analysis of the word “intelligence” suggests that it originally r...

  1. Artificial Personality and Disfluency

    OpenAIRE

    Wester, Mirjam; Aylett, Matthew; Tomalin, Marcus; Dall, Rasmus

    2015-01-01

    The focus of this paper is artificial voices with different personalities. Previous studies have shown links between an individual's use of disfluencies in their speech and their perceived personality. Here, filled pauses (uh and um) and discourse markers (like, you know, I mean) have been included in synthetic speech as a way of creating an artificial voice with different personalities. We discuss the automatic insertion of filled pauses and discourse markers (i.e., fillers) into otherwise f...

  2. The Artificial Anal Sphincter

    OpenAIRE

    Christiansen, John

    2000-01-01

    The artificial anal sphincter as treatment for end stage anal incontinence was first described in 1987. Published series concern a total of 42 patients, with a success rate of approximately 80%. Infection has been the most serious complication, but a number of technical complications related to the device have also occurred and required revisional procedures in 40% to 60% of the patients. The artificial anal sphincter may be used for the same indications as dynamic graciloplasty except in pat...

  3. Raytracing of extreamely low frequency waves radiated from ionospheric artificial modulation at low latitude%低纬电离层人工调制所激发的ELF波射线追踪

    Institute of Scientific and Technical Information of China (English)

    汪枫; 赵正予; 常珊珊; 倪彬彬; 顾旭东

    2012-01-01

    通过大功率极低频(ELF)/甚低频(VLF)高频调幅波能有效地扰动低电离层电流,形成等效的ELF/VLF电离层虚拟天线,辐射ELFNLF波,所辐射出的低频信号能够传播进入到磁层,对其传播特性的研究对于理解辐射带高能电子沉降具有重要意义.本文基于磁层射线追踪理论,通过数值模拟得到在低纬地区所激发出的ELF波在磁层中的射线路径,并对其特征进行分析.数值模拟结果表明,从低纬激发的ELF波在南北半球来回弹跳,并逐渐传播到更远处,对于不同频率的ELF波,频率越高,传播距离越近,频率越低,传播距离越远,在传播过程中,ELF波会逐渐倾向于在一个固定的磁层区域附近来回反射,在此过程中波法向角也逐渐变为90°,射线方向倾向于沿着背景磁场方向传播.%Powerful high-frequency radio waves modulated at extremely low frequency (ELF) and very low frequency (VLF) can efficiently modify the lower ionospheric current which can act as an equivalent ionospheri'c antenna for the generation of ELF/VLF wave and these signals can propagate into the magnetosphere and the investigation of the propagation properties is of significance for understanding of radiation belt energetic electrons precipitation. In this paper, based on the raytracing theory, the ray paths of ELF waves in the magnetosphere are obtained using numerical modeling and the properties are analyzed. The results shows that the ELF waves generated from the low latitude reflect between the southern and northern hemisphere and propagate to the farther place gradually. For the signals with different frequencies, the higher their frequencies, the shorter their propagation distances are, the lower their frequencies, the longer their propagtion distances are. In the process, ELF waves tend to reflect near a fixed region. The normal angel increases to 90° gradually and ray direction tends to

  4. New measurements of whistler-mode waves in the outer Van Allen belt: multicomponent wave analyzer ELMAVAN for the Resonance mission

    Czech Academy of Sciences Publication Activity Database

    Kolmašová, Ivana; Santolík, Ondřej; Lán, Radek; Uhlíř, Luděk; Chugunin, D.; Korepanov, V.; Boychev, B.; Pronenko, V.

    2013. [Radiation Belts Workshop: Comprehending, Specifying and Forecasting their Dynamics. 30.06.2013-03.07.2013, Santorini] Grant ostatní: FP7-MAARBLE(XE) 284520 Source of funding: R - rámcový projekt EK Institutional support: RVO:68378289 Keywords : whistler-mode waves * Van Allen belt * ELMAVAN Subject RIV: BL - Plasma and Gas Discharge Physics http://space-env.esa.int/indico/conferenceDisplay.py/abstractBook?confId=20

  5. Artificial skin. Jinko hifu

    Energy Technology Data Exchange (ETDEWEB)

    Kifune, K. (Unitika Ltd., Osaka (Japan))

    1993-06-15

    In order to restore the human skin wounds, the transplantation is only one measure. The transplantation can take only when own skin is used, and there is no successful example by using other person's skin. When the own skin is not sufficient due to the too vast damage, the artificial skin, which can be regenerated as it is, is required. The artificial skin is said to be the most difficult organ among the artificial organs, even though its function is quite simple. Although there are the pig skin, the collagen membrane and the synthetic materials such as the polyurethane and so forth, as the materials similar to the artificial skin, they cover the wounds just until the cuticle is formed. Recently there is a cultivated skin. Firstly the normal skin with a size of the stamp is cut off, and then the cuticle cells are taken to pieces and cultivated, and consequently it is possible to increase the area by several 10 times. In addition, there is also a trial to make the artificial skin synthetically. Its upper layer is composed of the silicon, and the lower layer is the collagen membrane with a sponge structure. The silicon, membrane can be said to be an ideal artificial skin, because it detaches naturally. The chitin, which has recently appeared as the wound protection material, is also the promising material. 3 figs.

  6. Stagnation, circulation, and erosion of granular materials through belt conveyor sluice gate

    Science.gov (United States)

    Pohlman, Nicholas; Moralda, Michael; Dunne, Ryan

    2013-11-01

    Control of flow rates in conversion reactors for discrete materials like biomass can be achieved in belt conveyors through a combination of belt speed, hopper size, and aperture opening. As material is extracted from the bottom of the storage hopper, other material cannot achieve plug flow and therefore is restricted from exiting through a sluice-gate type opening. The excess material moves vertically from the opening causing a pile up and recirculation back along the free surface of the hopper. Experimental results obtained through high speed imaging show the position of the stagnation point as well as the rate of circulation is dependent on the mass flow rate achieved and instantaneous fill level. The movement of material into the plug flow along the belt allows verification of deposition models on erodible beds rather than rigid surfaces with artificial roughness of glued particles. Similarly, the pile-up at the exit influences the efficiency of the transport affecting the narrow energy return on investment of biomass resources. The laboratory-scale behavior can therefore be translated into industrial performance metrics for increased operational efficiency. This work is supported by the NSF REU Site Operation E-Tank under award number 1156789.

  7. Whistler-mode chorus emission inside Earth's radiation belts

    Czech Academy of Sciences Publication Activity Database

    Taubenschuss, Ulrich; Santolík, Ondřej

    Miltenberg : U.R.S.I. Landesausschuss in der Bundesrepublik Deutschland e.V, 2015. s. 53-54. [URSI Kleinheubacher Tagung 2015. 28.09.2005-30.09.2005, Miltenberg] Institutional support: RVO:68378289 Keywords : magnetosphere * electromagnetic whistler-mode Subject RIV: BL - Plasma and Gas Discharge Physics

  8. 电离层人工调制在水平分层电离层中所激发的ELF波辐射%Radiation of ELF waves by ionospheric artificial modulation into a stratified ionosphere

    Institute of Scientific and Technical Information of China (English)

    汪枫; 赵正予; 常珊珊; 赵光欣; 青海银

    2012-01-01

    通过大功率ELF/VIF调幅高频波能有效地扰动低电离层,形成等效的ELF/VLF电离层虚拟天线,用来辐射ELF/VLF波,所辐射出的低频信号可以进入中性大气层形成地球-电离层波导.本文基于调制加热模型,采用全波有限元算法计算由人工调制电离层所形成的电偶极矩所辐射出的ELF波在水平分层电离层中的波场,计算结果将与地面观测结果进行比较.模拟结果表明,所辐射出的ELF波在电离层中形成一个窄的准直波束,海面所能接收到的ELF信号强度为pT量级,并且频率越低,海面所接收到的场强就越小,与HAARP实验数据一致.结果还表明,低纬电离层对低频信号的传播衰减较大,并且所能透射出电离层的角度小,因此高纬地区更适合地球-电离层波导的激发.%Using powerful high-frequency radio waves modulated at ELF/VLF can efficiently modify the lower ionosphere which can act as an equivalent ELF/VLF virtual antenna for the generation of ELF/VLF waves which can propagate in the Earth-ionosphere waveguide. In this paper, based on the modulation model, a full-wave finite element method is used to calculate the field of the ELF waves radiated by the dipole moment which is produced by ionospheric artificial modulation in the stratified ionosphere and the calculated values are compared to the ground observation. The numerical modeling shows that these waves form a narrow collimated beam and the magnitude of field intensity of low frequency signals received on the sea is -pT which will become smaller when the frequency is lower and this result is in accordance with the laboratory data from HAARP. The result also shows that it has stronger attenuation and small angel penetrating the ionosphere for the low signal at low latitude, so that the excitation of the Earth-ionosphere waveguide is easier at high latitude.

  9. Detecting Extrasolar Asteroid Belts Through Their Microlensing Signatures

    CERN Document Server

    Lake, Ethan; Dong, Subo

    2016-01-01

    We propose that extrasolar asteroid belts can be detected through their gravitational microlensing signatures. Asteroid belt + star lens systems create so-called "pseudo-caustics", regions in the source plane where the magnification exhibits a finite but discontinuous jump. These features allow such systems to generate distinctive microlensing light curves across a wide region of belt parameter space and possess remarkably large lensing cross-sections. Sample light curves for a range of asteroid belt parameters are presented. In the near future, space-based microlensing surveys (e.g., WFIRST) may be able to discover extrasolar asteroid belts with masses of the order of $0.1 M_{\\oplus}$.

  10. Impacts of intense inward and outward ULF wave radial diffusion on the Van Allen belts

    Science.gov (United States)

    Mann, Ian; Ozeke, Louis; Rae, I. Jonathan; Murphy, Kyle

    2016-07-01

    During geomagnetic storms, the power in ultra-low frequency (ULF) waves can be orders of magnitude larger than that predicted by statistics determined from an entire solar cycle. This is especially true during the main phase and early recovery phase. These periods of enhanced storm-time ULF wave power can have significant impacts on the morphology and structure of the Van Allen belts. Either fast inward or outward radial diffusion can result, depending on the profiles of the electron phase space density and the outer boundary condition at the edge of the belts. Small changes in the time sequence of powerful ULF waves, and the time sequence of any magnetopause shadowing or the recovery of plamasheet sources relative to the ULF wave occurrence, have a remarkable impact on the resulting structure of the belts. The overall impact of the enhanced ULF wave power is profound, but the response can be very different depending on the available source flux in the plasmasheet. We review these impacts by examining ultra-relativistic electron dynamics during seemingly different storms during the Van Allen Probe era, including during the Baker et al. third radiation belt, and show the observed behaviour can be largely explained by differences in the time sequence of events described above.

  11. An icy Kuiper-Belt around the young solar-type star HD 181327

    CERN Document Server

    Lebreton, J; Thi, W -F; Roberge, A; Donaldson, J; Schneider, G; Maddison, S T; Ménard, F; Riviere-Marichalar, P; Mathews, G S; Kamp, I; Pinte, C; Dent, W R F; Barrado, D; Duchêne, G; Gonzalez, J -F; Grady, C A; Meeus, G; Pantin, E; Williams, J P; Woitke, P

    2011-01-01

    HD 181327 is a young F5/F6V star belonging to the Beta Pictoris moving group (12 Myr). It harbors an optically thin belt of circumstellar material at 90 AU. We aim to study the dust properties in the belt in details, and to constrain the gas-to-dust ratio. We obtained far-IR observations with the Herschel/PACS instrument, and 3.2 mm observations with the ATCA array. The geometry of the belt is constrained with newly reduced HST/NICMOS images that break the degeneracy between the disk geometry and the dust properties. We use the radiative transfer code GRaTer to compute a large grid of models, and we identify the grain models that best reproduce the Spectral Energy Distribution through a Bayesian analysis. We attempt to detect the [OI] and [CII] lines with PACS spectroscopy, providing observables to our photochemical code ProDiMo. The HST observations confirm that the dust is confined in a narrow belt. The continuum is detected in the far-IR with PACS and the disk is resolved with both PACS and ATCA. A medium ...

  12. Seat Belt Use Among Adult Workers - 21 States, 2013.

    Science.gov (United States)

    Boal, Winifred L; Li, Jia; Rodriguez-Acosta, Rosa L

    2016-01-01

    Roadway incidents involving motorized vehicles accounted for 24% of fatal occupational injuries in the United States during 2013 and were the leading cause of fatal injuries among workers.* In 2013, workers' compensation costs for serious, nonfatal injuries among work-related roadway incidents involving motorized land vehicles were estimated at $2.96 billion.(†) Seat belt use is a proven method to reduce injuries to motor vehicle occupants (1). Use of lap/shoulder seat belts reduces the risk for fatal injuries to front seat occupants of cars by 45% and the risk to light truck occupants by 60%.(§) To characterize seat belt use among adult workers by occupational group, CDC analyzed data from the 2013 Behavioral Risk Factor Surveillance System (BRFSS) and found that not always using a seat belt was significantly associated with occupational group after controlling for factors known to influence seat belt use. Occupational groups with the highest prevalences of not always using a seat belt included construction and extraction; farming, fishing, and forestry; and installation, maintenance, and repair. To increase seat belt use among persons currently employed, states can enact and enforce primary seat belt laws, employers can set and enforce safety policies requiring seat belt use by all vehicle occupants, and seat belt safety advocates can target interventions to workers in occupational groups with lower reported seat belt use. PMID:27309488

  13. LOAD DISTRIBUTION ON DRUMS OF DOUBLE DRIVE BELT CONVEYOR

    Institute of Scientific and Technical Information of China (English)

    薛河; 苏清祖; 马胜利

    1999-01-01

    The double drum drive is widely used on the mine belt conveyor, which are divided the rigid connected double drums and separately driving double drums according to connected method of two drums. Because of the change of real work condition, the load distribution is changed on the two drive drums, which may produce a slippage between a drum and belt. Slippage may intensify the wear of the drum, and sometimes causing the fire of the belt. This restricts the development toward narrow belt, high velocity and large power of belt conveyor. In this paper, the factors affecting the load distribution of two drums of double drum belt conveyor are'systematically analyzed and some computing formulas derived, by these formulas, the actual load distribution onthe two drums of rigid connected or separately driving belt conveyor can be separately calculated. These formulas also can be as the theory base for adjusting the driving force of two drums.

  14. Artificial intelligence in nanotechnology

    International Nuclear Information System (INIS)

    During the last decade there has been increasing use of artificial intelligence tools in nanotechnology research. In this paper we review some of these efforts in the context of interpreting scanning probe microscopy, the study of biological nanosystems, the classification of material properties at the nanoscale, theoretical approaches and simulations in nanoscience, and generally in the design of nanodevices. Current trends and future perspectives in the development of nanocomputing hardware that can boost artificial-intelligence-based applications are also discussed. Convergence between artificial intelligence and nanotechnology can shape the path for many technological developments in the field of information sciences that will rely on new computer architectures and data representations, hybrid technologies that use biological entities and nanotechnological devices, bioengineering, neuroscience and a large variety of related disciplines. (topical review)

  15. A belted kingfisher flies above KSC

    Science.gov (United States)

    1999-01-01

    A belted kingfisher soars over the Merritt Island National Wildlife Refuge, which shares a boundary with Kennedy Space Center. The pigeon-sized, blue-gray male is identified by the blue-gray breast band; females show a chestnut belly band. The belted kingfisher ranges throughout the United States and Canada, wintering south to Panama and the West Indies. They dive into the water for fish and may also take crabs, crayfish, salamanders, lizards, mice and insects. The 92,000-acre refuge is a habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles. The marshes and open water of the refuge also provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds.

  16. Alien Asteroid Belt Compared to our Own

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: Band of Light Comparison This artist's concept illustrates what the night sky might look like from a hypothetical alien planet in a star system with an asteroid belt 25 times as massive as the one in our own solar system (alien system above, ours below; see Figure 1). NASA's Spitzer Space Telescope found evidence for such a belt around the nearby star called HD 69830, when its infrared eyes spotted dust, presumably from asteroids banging together. The telescope did not find any evidence for a planet in the system, but astronomers speculate one or more may be present. The movie begins at dusk on the imaginary world, when HD 69830, like our Sun, has begun to set over the horizon. Time is sped up to show the onset of night and the appearance of a brilliant band of light. This light comes from dust in a massive asteroid belt, which scatters sunlight. In our solar system, anybody observing the skies on a moonless night far from city lights can see the sunlight that is scattered by dust in our asteroid belt. Called zodiacal light and sometimes the 'false dawn,' this light appears as a dim band stretching up from the horizon when the Sun is about to rise or set. The light is faint enough that the disk of our Milky Way galaxy remains the most prominent feature in the sky. (The Milky Way disk is shown perpendicular to the zodiacal light in both pictures.) In contrast, the zodiacal light in the HD 69830 system would be 1,000 times brighter than our own, outshining even the Milky Way.

  17. Stability of Triangular Equilibrium Points in the Photogravitational Restricted Three-Body Problem with Oblateness and Potential from a Belt

    Indian Academy of Sciences (India)

    Jagadish Singh; Joel John Taura

    2014-06-01

    We have examined the effects of oblateness up to 4 of the less massive primary and gravitational potential from a circum-binary belt on the linear stability of triangular equilibrium points in the circular restricted three-body problem, when the more massive primary emits electromagnetic radiation impinging on the other bodies of the system. Using analytical and numerical methods, we have found the triangular equilibrium points and examined their linear stability. The triangular equilibrium points move towards the line joining the primaries in the presence of any of these perturbations, except in the presence of oblateness up to 4 where the points move away from the line joining the primaries. It is observed that the triangular points are stable for 0 < < c and unstable for c ≤ ≤ $\\frac{1}{2}$, where c is the critical mass ratio affected by the oblateness up to 4 of the less massive primary, electromagnetic radiation of the more massive primary and potential from the belt, all of which have destabilizing tendencies, except the coefficient 4 and the potential from the belt. A practical application of this model could be the study of motion of a dust particle near a radiating star and an oblate body surrounded by a belt.

  18. Artificial ionospheric turbulence (review)

    International Nuclear Information System (INIS)

    This study is an analysis of artificial ionospheric turbulence (AIT) arising near the level at which a powerful wave is reflected with ordinary polarization. AIT is an inhomogeneous structure in the ionosphere with a size on the order of centimeters or tens of kilometers and with characteristic frequencies from a fraction of a hertz (aperiodic inhomogeneity) to several megahertz (plasma waves). The authors are primarily concerned with small-scale artificial ionospheric turbulence (SAIT), i.e., with inhomogeneities that are greatly extended along the geomagnetic field with transverse dimensions that are less than the wavelengths of the perturbing waves - the pumping waves (PW) - in a vacuum

  19. Understanding quaternions and the Dirac belt trick

    International Nuclear Information System (INIS)

    The Dirac belt trick is often employed in physics classrooms to show that a 2π rotation is not topologically equivalent to the absence of rotation whereas a 4π rotation is, mirroring a key property of quaternions and their isomorphic cousins, spinors. The belt trick can leave the student wondering if a real understanding of quaternions and spinors has been achieved, or if the trick is just an amusing analogy. The goal of this paper is to demystify the belt trick and to show that it suggests an underlying four-dimensional parameter space for rotations that is simply connected. An investigation into the geometry of this four-dimensional space leads directly to the system of quaternions, and to an interpretation of three-dimensional vectors as the generators of rotations in this larger four-dimensional world. The paper also shows why quaternions are the natural extension of complex numbers to four dimensions. The level of the paper is suitable for undergraduate students of physics.

  20. Substyles of belting: phonatory and resonatory characteristics.

    Science.gov (United States)

    Sundberg, Johan; Thalén, Margareta; Popeil, Lisa

    2012-01-01

    Belting has been described as speechlike, yell-like, or shouting voice production commonly used in contemporary commercial music genres and substantially differing from the esthetic of the Western classical voice tradition. This investigation attempts to describe phonation and resonance characteristics of different substyles of belting (heavy, brassy, ringy, nasal, and speechlike) and the classical style. A professional singer and voice teacher, skilled in these genres, served as the single subject. The recorded material was found representative according to a classification test performed by an expert panel. Subglottal pressure was measured as the oral pressure during the occlusion for the consonant /p/. The voice source and formant frequencies were analyzed by inverse filtering the audio signal. The subglottal pressure and measured flow glottogram parameters differed clearly between the styles heavy and classical assuming opposite extremes in most parameters. The formant frequencies, by contrast, showed fewer less systematic differences between the substyles but were clearly separated from the classical style with regard to the first formant. Thus, the differences between the belting substyles mainly concerned the voice source. PMID:21439776

  1. Araguaia fold belt, new geochronological data

    International Nuclear Information System (INIS)

    The northern part of the Araguaia Fold Belt (AFB) outcrops in a N-S direction for about 400 km in the state of Tocantins. Dome-like structures occur in this fold belt also in a N-S direction. Both deformation and metamorphism increase from the West to the East. The basement of the AFB consist of Colmeia complex and Cantao gneiss, which crop out mainly in the core of the dome-like structures. The supracrustals rocks of the fold belt belongs to the Baixo Araguaia supergroup which is divided into the lower Estrondo group and the upper Tocantins group. Preliminary Sm-Nd data from the Colmeia complex (Grota Rica dome) gave Archean model ages of 2.8 Ga (TNd sub(DM)) while Rb-Sr data in the same rocks give an age of 2530 ± 200 Ma. In the others dome-like structures, the Rb-Sr systematics gave ages for the Colmeia a complex of 2239 ± 47 Ma (Colmeia structure) and 1972 ± 46 Ma (Lontra structure). These younger ages are believed to represent partial to total isotopic resetting of the Rb-Sr system during the Transamazonian Event. The Rb-Sr studies of the Cantao gneiss gave an age of 1774 ± 31 Ma. (author)

  2. Seat belt use during pregnancy in Iran: attitudes and practices

    Institute of Scientific and Technical Information of China (English)

    Mojgan Karbakhsh; Zahra Ershadi; Ali Khaji; Fatemeh Rahimi-Sharbaf

    2010-01-01

    Objective: Seat belt use during pregnancy reduces injury to the mother and her fetus. During recent years, the use of seat belts has been mandated by law in Iran. The purpose of this study was to determine the attitudes and practices of pregnant women regarding seat belt use.Methods: In this cross-sectional study, we asked 335 pregnant women at a hospital-based prenatal care clinic on the use of safety belt before and during pregnancy. SPSS version 13.0 was used for data analysis.Results: The mean age of study subjects was 27.3 years±5.3 years with the median of 27 years. Compared with the seat belt use before pregnancy, no change was detected in 48.7% of the women; seat belt use had increased in 17.5 %of them and decreased in 33.8 %. Eighty-one percent of women knew the correct placing of both lap belt and shoulder belt. Only 4% of women had received education on proper restraint use during pregnancy.Conclusions: The prevalence of seat belt use during pregnancy is lower than reports which are mostly from developed nations. The fact that about one-third of women have decreased their seat belt usage during pregnancy highlights the importance of education of mothers on this topic.

  3. Production of artificial radioelements

    International Nuclear Information System (INIS)

    The techniques used in the production of artificial radioelements are described, with special emphasis on the following points: - nuclear reactions and use of reactors; - chemical separation methods and methods for enriching the activity of preparations; - protection of personnel and handling methods. (author)

  4. Artificial Left Ventricle

    CERN Document Server

    Ranjbar, Saeed; Meybodi, Mahmood Emami

    2014-01-01

    This Artificial left ventricle is based on a simple conic assumption shape for left ventricle where its motion is made by attached compressed elastic tubes to its walls which are regarded to electrical points at each nodal .This compressed tubes are playing the role of myofibers in the myocardium of the left ventricle. These elastic tubes have helical shapes and are transacting on these helical bands dynamically. At this invention we give an algorithm of this artificial left ventricle construction that of course the effect of the blood flow in LV is observed with making beneficiary used of sensors to obtain this effecting, something like to lifegates problem. The main problem is to evaluate powers that are interacted between elastic body (left ventricle) and fluid (blood). The main goal of this invention is to show that artificial heart is not just a pump, but mechanical modeling of LV wall and its interaction with blood in it (blood movement modeling) can introduce an artificial heart closed to natural heart...

  5. Observations of artificial satellites

    Directory of Open Access Journals (Sweden)

    A. MAMMANO

    1964-06-01

    Full Text Available The following publication gives the results of photographic
    observations of artificial satellites made at Asiago during the second
    and third year of this programme. The fixed camera technique and that
    with moving film (the latter still in its experimental stage have been used.

  6. Artificial intelligence within AFSC

    Science.gov (United States)

    Gersh, Mark A.

    1990-01-01

    Information on artificial intelligence research in the Air Force Systems Command is given in viewgraph form. Specific research that is being conducted at the Rome Air Development Center, the Space Technology Center, the Human Resources Laboratory, the Armstrong Aerospace Medical Research Laboratory, the Armamant Laboratory, and the Wright Research and Development Center is noted.

  7. Terahertz Artificial Dielectric Lens

    Science.gov (United States)

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M.

    2016-03-01

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices.

  8. Artificial Gravity Research Plan

    Science.gov (United States)

    Gilbert, Charlene

    2014-01-01

    This document describes the forward working plan to identify what countermeasure resources are needed for a vehicle with an artificial gravity module (intermittent centrifugation) and what Countermeasure Resources are needed for a rotating transit vehicle (continuous centrifugation) to minimize the effects of microgravity to Mars Exploration crewmembers.

  9. Spatially Resolved Artificial Chemistry

    DEFF Research Database (Denmark)

    Fellermann, Harold

    2009-01-01

    made a class of models accessible to the realms of artificial chemistry that represent reacting molecules in a coarse-grained fashion in continuous space. This chapter introduces the mathematical models of Brownian dynamics (BD) and dissipative particle dynamics (DPD) for molecular motion and reaction...

  10. Natural or Artificial Intelligence?

    Czech Academy of Sciences Publication Activity Database

    Havlík, Vladimír

    Plzeň: University of West Bohemia, 2013 - (Romportl, J.; Ircing, P.; Zackova, E.; Polak, M.; Schuster, R.), s. 15-27 ISBN 978-80-261-0275-5. [International Conference Beyond AI 2013. Plzeň (CZ), 12.11.2013-14.11.2013] Institutional support: RVO:67985955 Keywords : artificial intelligence * natural intelligence * artifact * natural process * intrinsic intentionality Subject RIV: AA - Philosophy ; Religion

  11. Artificial Intelligence and CALL.

    Science.gov (United States)

    Underwood, John H.

    The potential application of artificial intelligence (AI) to computer-assisted language learning (CALL) is explored. Two areas of AI that hold particular interest to those who deal with language meaning--knowledge representation and expert systems, and natural-language processing--are described and examples of each are presented. AI contribution…

  12. Micromachined Artificial Haircell

    Science.gov (United States)

    Liu, Chang (Inventor); Engel, Jonathan (Inventor); Chen, Nannan (Inventor); Chen, Jack (Inventor)

    2010-01-01

    A micromachined artificial sensor comprises a support coupled to and movable with respect to a substrate. A polymer, high-aspect ratio cilia-like structure is disposed on and extends out-of-plane from the support. A strain detector is disposed with respect to the support to detect movement of the support.

  13. An Artificial Gravity Spacecraft Approach which Minimizes Mass, Fuel and Orbital Assembly Reg

    Science.gov (United States)

    Bell, L.

    2002-01-01

    radiation storm shelter is provided for periods spent in the Van Allen Belt vicinity and for protection during possible solar energetic particle events. AGSEV planning baselines use of Shuttle Orbiters for element launches to LEO, and oxygen-hydrogen propulsion utilizing Shuttle External Tanks for storage as worst-case scenarios. The need for an economical heavy-lift launch vehicle and much more efficient alternative to chemical propulsion are recognized.

  14. Circuitry for the automatic tare balancing at radiometric weigh-feeder belts

    International Nuclear Information System (INIS)

    The invention has been aimed at a circuitry for the automatic tare balancing at radiometric weigh-feeder belts with digital data processing of the measurement pulse rate emitted by a radiation detector during a measuring cycle. To secure a non-perturbational and exact permanent pulse rate correction by the tare rate the measuring pulse rate is summed up under the operational mode 'taring' for a preselected rotation time of the empty belt and evaluated using a factor related to the length of measuring cycle. The resulting pulses are stored as an average value. Under the operational mode 'weighing' the difference between pulse rate and stored tare pulses will be formed and transmitted to a data processing unit

  15. Introduction to Artificial Neural Networks

    DEFF Research Database (Denmark)

    Larsen, Jan

    1999-01-01

    The note addresses introduction to signal analysis and classification based on artificial feed-forward neural networks.......The note addresses introduction to signal analysis and classification based on artificial feed-forward neural networks....

  16. Inflatable artificial sphincter - series (image)

    Science.gov (United States)

    An artificial urinary sphincter is used to treat stress incontinence in men that is caused by urethral dysfunction such ... An artificial sphincter consists of three parts: a cuff that fits around the bladder neck a pressure regulating balloon ...

  17. Health Monitoring for Coated Steel Belts in an Elevator System

    OpenAIRE

    Yimei Mao; Zuoying Huang; Guiyun Tian; Hui Zhao; Huaming Lei

    2012-01-01

    This paper presents a method of health monitoring for coated steel belts in an elevator system by measuring the electrical resistance of the ropes embedded in the belt. A model on resistance change caused by fretting wear and stress fatigue has been established. Temperature and reciprocating cycles are also taken into consideration when determining the potential strength degradation of the belts. It is proved by experiments that the method could effectively estimate the health degradation of ...

  18. Artificial Intelligence and Information Retrieval.

    Science.gov (United States)

    Teodorescu, Ioana

    1987-01-01

    Compares artificial intelligence and information retrieval paradigms for natural language understanding, reviews progress to date, and outlines the applicability of artificial intelligence to question answering systems. A list of principal artificial intelligence software for database front end systems is appended. (CLB)

  19. Effects of ionizing radiation

    International Nuclear Information System (INIS)

    Starting with a brief introduction to radiation protection, the report gives an overview of exposure to ionising radiation in Belgium due to activities in relation to the nuclear fuel cycle, processing and disposal of radioactive waste and other artificial or natural sources. Where appropriate, the Belgian situation discussed from an international perspective. The radiological impact of reprocessing and non-reprocessing are compared. The biological effects of ionizing radiation, epidemiological studies as well as surveillance programmes on the Belgian territory are reported on

  20. Car safety belts: a study of two models adapted for people with arthritis.

    Science.gov (United States)

    Arie, E

    1986-05-01

    People with arthritis find car seat belts difficult to use. Sixteen arthritic patients and 19 healthy volunteers completed a comparative study of one standard inertia-reel belt and two adapted inertia-reel belts with reduced retraction forces. Those with arthritis were strong enough to use the standard belt but both adapted belts had features making them easier to use. PMID:3708235

  1. Rirang Uranium Ore Processing System Design Horizontal Belt Filter

    International Nuclear Information System (INIS)

    Horizontal belt filter one of the solid-liquid separation process equipment. The design of Horizontal Belt Filter have been conducted for capacity of 250 g/minute. The result obtained was filtering velocity of 0,4 g/cm2 minute. The linear belt speeds 100 cm/minute. The length and width of the belt 125 cm also the filtering cycle of 1,25 minute. The operation of that equipment give result about 77,9 - 79,1% of product cake

  2. Health Monitoring for Coated Steel Belts in an Elevator System

    Directory of Open Access Journals (Sweden)

    Huaming Lei

    2012-01-01

    Full Text Available This paper presents a method of health monitoring for coated steel belts in an elevator system by measuring the electrical resistance of the ropes embedded in the belt. A model on resistance change caused by fretting wear and stress fatigue has been established. Temperature and reciprocating cycles are also taken into consideration when determining the potential strength degradation of the belts. It is proved by experiments that the method could effectively estimate the health degradation of the most dangerous section as well as other ones along the whole belts.

  3. Experiences and best practices in the use of PCPs in Orinoco Belt, Carabobo area, Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, M.A.; Brown, J.C.; Quijada, M.; Parra, R.; Romero, J. [Petroleos de Venezuela, Caracas (Venezuela); Seince, L. [PCM, Vanves (France)

    2008-07-01

    Artificial lift methods used to produce heavy oil in Venezuela's Orinoco oil belt were discussed. Progressive cavity pumps (PCPs) have been used in the region since the 1990s as an alternative method of producing the region's heavy oil. Artificial lift is now used in over 50 per cent of the region's producing wells, and accounts for approximately 45 per cent of current production. This paper discussed modifications made to the PCP implementation process, new designs, improvements to fluid handling capabilities, and reduced costs. The region has developed artificial lift systems as well as new horizontal and multi-lateral wells. PCP production methods have reduced the lifting cost and increased the reliability of the system. Modifications included pump capacity, downhole pressure sensors, top drives and variable speeds. The use of PCP in vertical and deviated wells. Gas separators have been designed to increase pumping efficiencies, reduced carbon dioxide (CO{sub 2}) emissions and corrosion. 3 refs., 2 tabs., 11 figs.

  4. Predicting Facies Patterns within Fluvial Channel Belts

    Science.gov (United States)

    Willis, B. J.; Sech, R.; Sun, T.; Pyrcz, M.

    2014-12-01

    Reservoirs (aquifers) in fluvial channel belt sandstones can have very different subsurface flow behavior depending on the degree and distribution of internal heterogeneities. Fluvial channel belts are composed of multiple "storeys" formed as individual channel segments increase in sinuosity and then are cut off and abandoned. Heterogeneities are defined by depositional variations across storeys and inter-story connectivity patterns along the channel belt. Although commonly inferred to reflect the formative river pattern (sinuosity & braiding), the spatial arrangement of facies depend most directly on the relative preservation of deposits formed within different areas of the migrating channels and the lateral stacking arrangement of storeys due to style of bend cutoff. Grains are poorly sorted across the inner bank along upstream parts of channel bends and become better sorted laterally in downstream areas adjacent to a deeper thalweg scour. If deposition occurs evenly along the entire inner bank (bar), this grain size pattern leads to an elliptical body in planview with weak vertical grain size trends upstream and more fining-upward trend downstream. As channel bend segments migrate to a greater extent downstream, preserved inner-bank-bar deposits are increasingly dominated by upward-fining deposits and more outer-bank-deposits are preserved ("concave bank" deposits). Although concave bank deposits have highly variable character in different systems, vertical-grainsize trends tend to be weaker in straighter systems dominated by downstream-accretion, and more strongly upward-fining in higher sinuosity systems where these deposits form by eddy accretion or low flow aggradation. River cutoffs of straighter channel segments abandon slowly, leading to more gradual vertical fining. Subsurface heterogeneity prediction requires documentation of shape and character of deposits preserved in different zones within the channel (upstream and downstream inner bank, concave bank

  5. Tailoring superradiance to design artificial quantum systems

    Science.gov (United States)

    Longo, Paolo; Keitel, Christoph H.; Evers, Jörg

    2016-03-01

    Cooperative phenomena arising due to the coupling of individual atoms via the radiation field are a cornerstone of modern quantum and optical physics. Recent experiments on x-ray quantum optics added a new twist to this line of research by exploiting superradiance in order to construct artificial quantum systems. However, so far, systematic approaches to deliberately design superradiance properties are lacking, impeding the desired implementation of more advanced quantum optical schemes. Here, we develop an analytical framework for the engineering of single-photon superradiance in extended media applicable across the entire electromagnetic spectrum, and show how it can be used to tailor the properties of an artificial quantum system. This “reverse engineering” of superradiance not only provides an avenue towards non-linear and quantum mechanical phenomena at x-ray energies, but also leads to a unified view on and a better understanding of superradiance across different physical systems.

  6. Energy in corn belt crop production

    Energy Technology Data Exchange (ETDEWEB)

    Lockeretz, W.; Klepper, R.; Gertler, M.; Fast, S.; O' Leary, D.

    1975-07-01

    The study presents data on the quantity and cost of the energy used to produce corn, soybeans, and wheat in the western part of the Corn Belt in 1974. The analysis covers fuel for field equipment, energy required to manufacture fertilizers and pesticides, and energy for drying corn. Corn is the most energy-intensive of the three crops studied, with soybeans the lowest. The cost of energy for crop production amounts to 11%, 8%, and 6% of the overall direct production costs for corn, wheat, and soybeans, respectively. These energy costs come to less than 3% of the value of the crop in all three cases. (GRA)

  7. Meningococcal carriage in the African meningitis belt

    OpenAIRE

    2013-01-01

    A meningococcal serogroup A polysaccharide/tetanus toxoid conjugate vaccine (PsA-TT) (MenAfriVac#x2122;) is being deployed in countries of the African meningitis belt. Experience with other polysaccharide/protein conjugate vaccines has shown that an important part of their success has been their ability to prevent the acquisition of pharyngeal carriage and hence to stop transmission and induce herd immunity. If PsA-TT is to achieve the goal of preventing epidemics, it must be able to prevent ...

  8. Parametric resonances of convection belt system

    Institute of Scientific and Technical Information of China (English)

    Zhi-an YANG; Gao-feng LI

    2009-01-01

    Based on the Coriolis acceleration and the Lagrangian strain formula,a generalized equation for the transverse vibration system of convection belts is derived using Newton's second law.The method of multiple scales is directly applied to the governing equations,and an approximate solution of the primary parameter resonance of the system is obtained.The detuning parameter,cross-section area,elastic and viscoelastic parameters,and axial moving speed have a significant influences on the amplitudes of steady-state response and their existence boundaries.Some new dynamical phenomena are revealed.

  9. Artificial Enzymes, "Chemzymes"

    DEFF Research Database (Denmark)

    Bjerre, Jeannette; Rousseau, Cyril Andre Raphaël; Pedersen, Lavinia Georgeta M;

    2008-01-01

    Enzymes have fascinated scientists since their discovery and, over some decades, one aim in organic chemistry has been the creation of molecules that mimic the active sites of enzymes and promote catalysis. Nevertheless, even today, there are relatively few examples of enzyme models that...... successfully perform Michaelis-Menten catalysis under enzymatic conditions (i.e., aqueous medium, neutral pH, ambient temperature) and for those that do, very high rate accelerations are seldomly seen. This review will provide a brief summary of the recent developments in artificial enzymes, so called...... "Chemzymes", based on cyclodextrins and other molecules. Only the chemzymes that have shown enzyme-like activity that has been quantified by different methods will be mentioned. This review will summarize the work done in the field of artificial glycosidases, oxidases, epoxidases, and esterases, as well as...

  10. Artificial organisms that sleep.

    OpenAIRE

    Mirolli, Marco; Parisi, Domenico

    2003-01-01

    Abstract Populations of artificial organisms live in an environment in which light is cyclically present (day) or absent (night). Since being active during night is non-adaptive (activity consumes energy which is not compensated by the food found at night) the organisms evolve a sleep/wake behavioral pattern of being active during daytime and sleeping during nighttime. When the population moves to a different environment that contains "caves", they have to get out of a cave although the dark ...

  11. Impacts of Artificial Intelligence

    OpenAIRE

    Trappl, R.

    1986-01-01

    This book, which is intended to serve as the first stage in an iterative process of detecting, predicting, and assessing the impacts of Artificial Intelligence opens with a short "one-hour course" in AI, which is intended to provide a nontechnical informative introduction to the material which follows. Next comes an overview chapter which is based on an extensive literature search, the position papers, and discussions. The next section of the book contains position papers whose richness...

  12. Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Kapil Nahar

    2012-12-01

    Full Text Available An artificial neural network is an information-processing paradigm that is inspired by the way biological nervous systems, such as the brain, process information. The key element of this paradigm is the novel structure of the information processing system. It is composed of a large number of highly interconnected processing elements (neurons working in unison to solve specific problems. Ann’s, like people, learn by example.

  13. Artificial Intelligence in Transition

    OpenAIRE

    Hart, Peter E.

    1984-01-01

    In the past fifteen years artificial intelligence has changed from being the preoccupation of a handful of scientists to a thriving enterprise that has captured the imagination of world leaders and ordinary citizens alike. While corporate and government officials organize new projects whose potential impact is widespread, to date few people have been more affected by the transition than those already in the field. I review here some aspects of this transition, and pose some issues that it rai...

  14. Artificial neural network modelling

    CERN Document Server

    Samarasinghe, Sandhya

    2016-01-01

    This book covers theoretical aspects as well as recent innovative applications of Artificial Neural networks (ANNs) in natural, environmental, biological, social, industrial and automated systems. It presents recent results of ANNs in modelling small, large and complex systems under three categories, namely, 1) Networks, Structure Optimisation, Robustness and Stochasticity 2) Advances in Modelling Biological and Environmental Systems and 3) Advances in Modelling Social and Economic Systems. The book aims at serving undergraduates, postgraduates and researchers in ANN computational modelling. .

  15. Intelligence, Artificial and Otherwise

    OpenAIRE

    Chace, William M.

    1984-01-01

    I rise now to speak with the assumption that all of you know very well what I am going to say. I am the humanist here, the professor of English. We humanists, when asked to speak on questions of science and technology, are notorious for offering an embarrassed and ignorant respect toward those matters, a respect, however, which can all too quickly degenerate into insolent condescension. Face to face with the reality of computer technology, say, or with "artificial intelligence," we humanists ...

  16. Mental models of radiation

    International Nuclear Information System (INIS)

    Laymen and experts participated in interviews designed to reveal their 'mental models' of the processes potentially causing the miscommunications between experts and the public. We analyzed their responses in terms of an 'expert model' circumscribing scientifically relevant information. From results, there are gaps even between experts. Experts on internal exposure focused mainly on artificial radiation and high level of radiation. Experts on radiation biology focused on medical radiation, level of risk, environmental radiation, and hot springs. Experts on dosimetric performance focused on atomic power generation and needs of radiological protection. It means that even experts, they have interests only on their own specialized field. (author)

  17. Artificial sweetener; Jinko kanmiryo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-08-01

    The patents related to the artificial sweetener that it is introduced to the public in 3 years from 1996 until 1998 are 115 cases. The sugar quality which makes an oligosaccharide and sugar alcohol the subject is greatly over 28 cases of the non-sugar quality in the one by the kind as a general tendency of these patents at 73 cases in such cases as the Aspartame. The method of manufacture patent, which included new material around other peptides, the oligosaccharide and sugar alcohol isn`t inferior to 56 cases of the formation thing patent at 43 cases, and pays attention to the thing, which is many by the method of manufacture, formation. There is most improvement of the quality of sweetness with 31 cases in badness of the aftertaste which is characteristic of the artificial sweetener and so on, and much stability including the improvement in the flavor of food by the artificial sweetener, a long time and dissolution, fluid nature and productivity and improvement of the economy such as a cost are seen with effect on a purpose. (NEDO)

  18. Ambient radioactivity levels and radiation doses. Annual report 2012

    International Nuclear Information System (INIS)

    The annual report 2012 on ambient radioactivity levels and radiation doses covers the following issues: Part A: General information: natural environmental radioactivity; artificial radioactivity in the environment; occupational radiation exposure; radiation exposures from medical applications; the handling of radioactive materials and sources of ionizing radiation; non-ionizing radiation. Part B: Current data and their evaluation: natural environmental radioactivity; artificial radioactivity in the environment; occupational radiation exposures; radiation exposures from medical applications; the handling of radioactive materials and sources of ionizing radiation; non-ionizing radiation. The report includes data on the stock of radioactive waste, radiation accidents and unusual events.

  19. Fading of Jupiter's South Equatorial Belt

    Science.gov (United States)

    Sola, Michael A.; Orton, Glenn; Baines, Kevin; Yanamandra-Fisher, Padma

    2011-01-01

    One of Jupiter's most dominant features, the South Equatorial Belt, has historically gone through a "fading" cycle. The usual dark, brownish clouds turn white, and after a period of time, the region returns to its normal color. Understanding this phenomenon, the latest occurring in 2010, will increase our knowledge of planetary atmospheres. Using the near infrared camera, NSFCAM2, at NASA's Infrared Telescope Facility in Hawaii, images were taken of Jupiter accompanied by data describing the circumstances of each observation. These images are then processed and reduced through an IDL program. By scanning the central meridian of the planet, graphs were produced plotting the average values across the central meridian, which are used to find variations in the region of interest. Calculations using Albert4, a FORTRAN program that calculates the upwelling reflected sunlight from a designated cloud model, can be used to determine the effects of a model atmosphere due to various absorption, scattering, and emission processes. Spectra that were produced show ammonia bands in the South Equatorial Belt. So far, we can deduce from this information that an upwelling of ammonia particles caused a cloud layer to cover up the region. Further investigations using Albert4 and other models will help us to constrain better the chemical make up of the cloud and its location in the atmosphere.

  20. The Dynamical Evolution of the Asteroid Belt

    CERN Document Server

    Morbidelli, Alessandro; O'Brien, David P; Minton, David A; Bottke, William F

    2015-01-01

    The asteroid belt is the leftover of the original planetesimal population in the inner solar system. However, currently the asteroids have orbits with all possible values of eccentricities and inclinations compatible with long-term dynamical stability, whereas the initial planetesimal orbits should have been quasi-circular and almost co-planar. The total mass in the asteroid population is a small fraction of that existing primordially. Also, asteroids with different chemical/mineralogical properties are not ranked in an orderly manner with mean heliocentric distance as one could expect from the existence of a radial gradient of the temperature in the proto-planetary disk, but they are partially mixed. These properties show that the asteroid belt has been severely sculpted by one or a series of processes during its lifetime. This paper reviews the processes that have been proposed so far, discussing the properties that they explain and the problems that they are confronted with. Emphasis is paid to the interpl...

  1. Stabilization of electrostatic accelerator charging belt current

    International Nuclear Information System (INIS)

    For the purpose of improving reliability and quality of electrostatic accelerator basic parameters the stabilizer of charging belt current is developed. The stabilizer consists of two units: high-voltage unit and control unit. The charging rectifier assures voltage up to 60 kV at total current load of 750 μA. For the EG- 2.5 and the EGP-10 M accelerators supply circuits of charging device with an earth screen and posAitive voltage supply the needles. t the EGP-10-1 accelerator negative charging voltage is supplied to the screens of the charging device. ''Plus'' of the rectifier is earthed. Charging and recharging are performed by means of brushes slipping over the internal belt side. At all accelerators the stability of charging current mean value is not worse 0.1%. The highest response of the system are obtained at the EG-2.5 accelerator for account of rectifier load by charging current and instrument resistor from 140 to 400 MOhm

  2. 30 CFR 57.4263 - Underground belt conveyors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground belt conveyors. 57.4263 Section 57... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Fire Prevention and Control Firefighting Equipment § 57.4263 Underground belt conveyors. Fire protection shall...

  3. Safety belt usage in Finland and in other Nordic countries.

    NARCIS (Netherlands)

    Valtonen, J.

    1992-01-01

    Legislation has played a significant role in increasing safety belt usage in Finland and in the other Nordic countries. Publicity and enforcement have, however, been required to support the legislation. The development of safety belt regulations has been nearly similar in all these countries, both i

  4. Canadian seat belt wearing rates, promotion programs, and future directions.

    NARCIS (Netherlands)

    Grant, B.A.

    1992-01-01

    On the basis of a national driver seat belt survey conducted in Canada each year, the most important results are presented. A number of programmes for increasing seat belt use has been evaluated in Canada. Finally, a description is given of some of the current and planned activities within Canada wh

  5. Respiratory Belt Transducer Constructed Using a Singing Greeting Card Beeper

    Science.gov (United States)

    Bhaskar, Anand; Subramani, Selvam; Ojha, Rajdeep

    2013-01-01

    An article by Belusic and Zupancic described the construction of a finger pulse sensor using a singing greeting card beeper. These authors felt that this beeper made of piezoelectric material could be easily modified to function as a respiratory belt transducer to monitor respiratory movements. Commercially available respiratory belt transducers,…

  6. A belt charging system for the Vivitron - design, early results

    International Nuclear Information System (INIS)

    A specific belt charging system has been designed, built and assembled for the 35 MV Vivitron. 100 m long belt is used. Together with main features of the design, experimental studies, tests in a pilot machine and the results of the very early tests of the real system are reviewed

  7. Storm/substorm signatures in the outer belt

    International Nuclear Information System (INIS)

    The response of the ring current region is compared for periods of storm and substorm activity, with an attempt to isolate the contributions of both processes. The authors investigate CRRES particle data in an overview format that allows the display of long-term variations of the outer radiation belt. They compare the evolution of the ring current population to indicators of storm (Dst) and substorm (AE) activity and examine compositional changes. Substorm activity leads to the intensification of the ring current at higher L (L ∼ 6) and lower ring current energies compared to storms (L ∼ 4). The O+/H+ ratio during substorms remains low, near 10%, but is much enhanced during storms (can exceed 100%). They conclude that repeated substorms with an AE ∼ 900 nT lead to a ΔDst of ∼ 30 nT, but do not contribute to Dst during storm main phase as substorm injections do not form a symmetric ring current during such disturbed times

  8. International Workshop on First Decadal Review Of The Edgeworth-kuiper-belt : Towards New Frontiers

    CERN Document Server

    Barrera, Luis; Towards New Frontiers

    2004-01-01

    A decade after the confirmation of the Kuiper Belt's existence, 80 of the world's experts gathered in Chile to review what has been learned since 1992. This record of the meeting is enhanced by several specially solicited papers covering additional material not presented at the conference. The volume includes papers on the dynamics of the trans-Neptunian region, the results of deep surveys for the new objects and the evidence for an outer Edge to the Edgeworth-Kuiper belt. Physical observations of many objects are described and attempts are made to bring these data into some coherent picture of the distant solar system. The interior physics of these distant, icy objects, and the link between the Kuiper Belt and dust disks around other stars are also considered. Of particular interest is a set of papers on how the surfaces of distant asteroids are affected by various types of radiation, an area crucial to the interpretation of data being collected by large ground based telescopes. Suitable for professi...

  9. High-Voltage Tethers For Enhanced Particle Scattering In Van Allen Belts

    Science.gov (United States)

    Mirnov, Vladimir; Ü, Defne; Danilov, Valentin

    1996-11-01

    New applications of space tethers (HVTSS) are discussed in relation with the ideafootnote Yu.V.Vasilyev, V.V.Danilov, Physics-Doklady, (1995) 342, 5. of an active experiment at the Earth's radiation belts. Two conducting strings are supposed to be tethered between the main satellite and two small subsatellites flying through the ERB. A large potential difference ~1MV is applied between the tethers by means of a generator carried on the main satellite. The tethers effectively scatter the high energy particles into loss cone, providing a control of particle life time in ERB. The rigorous theory of the sheath layer formed by relatively cold plasma is developed for both DC and AC regimes yielding an electric field profile, which is then used for the treatment of the scattering problem. With the help of the Fokker-Planck equation, the average rate of particle losses, normalized per 1 km of the theter's length is found to be: (2.5 div 14)× 10^16 sec-1km-1 for electron belts and 1.8× 10^14div 2.5× 10^20 sec-1km-1 for proton belts. New active experiments in ERB become possible under the joint realization of HVTSS and HAARPfootnote D.Papadopoulos, P.Bernhardt et al. A Joint Program of Phillips Lab and the Office of Naval Research, June, 1995 projects.

  10. Radiation exposure and biological problems in space flights

    International Nuclear Information System (INIS)

    The porblems of dosimetry of cosmic rays in space flights are dealt with. Because of the different amounts of radiation involved, the galactic primary radiation is treated separately from the radiation in the flares and in the radiation belt which superpose it in time or region. The estimated dose equivalent of the galactic primary radiation is 77 mrem/24 h. Flare bursts on the other hand, may produce a dose equivalent of 100-1,000 rem. In the radiation belt, radiation doses up to a maximum of 100 rem per day have to be expected. The problem of dosimetry of high-energetic corpuscular radiation with extremely high LET is treated in detail. For an assessment of possible radiation hazards, microdosimetric methods will have to be applied. Most susceptible to radiation lesions caused by high-energetic ions are cerebral and spinal cells as well as ganglion cells of the retina. (ORU/AK)

  11. Experimental Measurements of Belt Gears in Newly Developed Device

    Directory of Open Access Journals (Sweden)

    Jozef Mascenik

    2016-05-01

    Full Text Available The paper deals with the alternative of determination of state of the belt gear. To realize themeasurements a newly developed device was designed for measurement and diagnostics of the belt gears. The main task is to detect the V-belt slip expressed by the coefficient of elastic creep and of specific slip with a measuring device. The measurements regarding can be performed if input revolutions of the electric motor and torque of the belt gear are constant whereas the tensioning force of the belt gear changes. It is also possible to perform the measurement if the input revolutions of the electric motor and the tensioning forces are constant and the torque changes.

  12. Traffic restrictions due to wind on the Fehmarn Belt bridge

    DEFF Research Database (Denmark)

    Dellwik, E.; Mann, Jakob; Rosenhagen, G.

    2006-01-01

    same as used in this report and here the comparison is satisfactory. We estimate that the prospective Fehmarn Belt bridge will be closed roughly 2% of the timefor light roadway vehicles (unloaded trucks and caravans), corresponding to 7 days per year. This is slightly less than for the Fehmarnsund...... Bridge. For the Great Belt bridge the corresponding actual fraction is 1.5%, despite the fact that this bridge usesstricter criteria. The most important difference between the bridges in this connection is their orientation with respect to the prevailing wind direction. If all the large bridges (Øresund......, Great Belt and Fehmarn Belt) used the same criteria the FehmarnBelt bridge would be closed approximately twice as much as the two others. The majority of these restrictions are likely to take place in the winter time and can be significantly reduced with wind screens....

  13. The future of artificial intelligence in nuclear plant maintenance

    International Nuclear Information System (INIS)

    Robots with vision and force sensing capability, performing tasks under computer control, will offer new opportunities to reduce human exposure to radiation. Such machines do not yet exist and even simple maintenance tasks challenge current robot technology. Recently increased priority for research on artificial intelligence and fifth generation computer technology is likely to bring useful maintenance robots closer to reality

  14. Chronology of generation, variation, and disappearance of a second proton belt as determined by effects in electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Stassinopoulos, E.G. [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center; Brucker, G.J. [Brucker (G.J.), West Long Beach, NJ (United States); Stauffer, C.A. [SES, Greenbelt, MD (United States); Meulenberg, A. [COMSAT Labs., Clarksburg, MD (United States)

    1995-12-01

    This paper presents an analysis of SEU data obtained from memory devices on the CRRES (Combined Release and Radiation Effects Satellite) spacecraft. It provides a dynamic picture of the newly identified second peak of the trapped proton belt in the equatorial region between approximately 2.0--2.8 Earth radii. In previous work, it was stated that injection of solar flare protons from the major flare of March 1991 generated this secondary belt which appears to have survived at least up to the demise of CRRES (October 12, 1991). The results of this study show that the radiation responsible for the observed effects existed intermittently in that region of space from the very beginning of the mission, that is July 27, 1990, during a period when there was no significant high energy flare activity (about 4.5 months), and then disappeared for three months until it reappeared again with the March 1991 flare.

  15. A Study on the Vibration of the Charging Belt in an Electrostatic Accelerator

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The vibration of the charging belt in an electrostatic accelerator has intense influences on the accelerator operation. A calculating model was set up in this paper to study the belt vibration. The results show that the belt tension, belt velocity and belt current all contribute to the belt vibration. There is an optimal relationship among the three factors by which the belt would run most smoothly. There exists a minimum value of optimal tension for various belt velocities. The vibrating frequency of the is generally around several Hz.

  16. Artificial intelligence in hematology.

    Science.gov (United States)

    Zini, Gina

    2005-10-01

    Artificial intelligence (AI) is a computer based science which aims to simulate human brain faculties using a computational system. A brief history of this new science goes from the creation of the first artificial neuron in 1943 to the first artificial neural network application to genetic algorithms. The potential for a similar technology in medicine has immediately been identified by scientists and researchers. The possibility to store and process all medical knowledge has made this technology very attractive to assist or even surpass clinicians in reaching a diagnosis. Applications of AI in medicine include devices applied to clinical diagnosis in neurology and cardiopulmonary diseases, as well as the use of expert or knowledge-based systems in routine clinical use for diagnosis, therapeutic management and for prognostic evaluation. Biological applications include genome sequencing or DNA gene expression microarrays, modeling gene networks, analysis and clustering of gene expression data, pattern recognition in DNA and proteins, protein structure prediction. In the field of hematology the first devices based on AI have been applied to the routine laboratory data management. New tools concern the differential diagnosis in specific diseases such as anemias, thalassemias and leukemias, based on neural networks trained with data from peripheral blood analysis. A revolution in cancer diagnosis, including the diagnosis of hematological malignancies, has been the introduction of the first microarray based and bioinformatic approach for molecular diagnosis: a systematic approach based on the monitoring of simultaneous expression of thousands of genes using DNA microarray, independently of previous biological knowledge, analysed using AI devices. Using gene profiling, the traditional diagnostic pathways move from clinical to molecular based diagnostic systems. PMID:16203606

  17. Polymer artificial muscles

    Directory of Open Access Journals (Sweden)

    Tissaphern Mirfakhrai

    2007-04-01

    Full Text Available The various types of natural muscle are incredible material systems that enable the production of large deformations by repetitive molecular motions. Polymer artificial muscle technologies are being developed that produce similar strains and higher stresses using electrostatic forces, electrostriction, ion insertion, and molecular conformational changes. Materials used include elastomers, conducting polymers, ionically conducting polymers, and carbon nanotubes. The mechanisms, performance, and remaining challenges associated with these technologies are described. Initial applications are being developed, but further work by the materials community should help make these technologies applicable in a wide range of devices where muscle-like motion is desirable.

  18. Uncertainty in artificial intelligence

    CERN Document Server

    Kanal, LN

    1986-01-01

    How to deal with uncertainty is a subject of much controversy in Artificial Intelligence. This volume brings together a wide range of perspectives on uncertainty, many of the contributors being the principal proponents in the controversy.Some of the notable issues which emerge from these papers revolve around an interval-based calculus of uncertainty, the Dempster-Shafer Theory, and probability as the best numeric model for uncertainty. There remain strong dissenting opinions not only about probability but even about the utility of any numeric method in this context.

  19. Bayesian artificial intelligence

    CERN Document Server

    Korb, Kevin B

    2010-01-01

    Updated and expanded, Bayesian Artificial Intelligence, Second Edition provides a practical and accessible introduction to the main concepts, foundation, and applications of Bayesian networks. It focuses on both the causal discovery of networks and Bayesian inference procedures. Adopting a causal interpretation of Bayesian networks, the authors discuss the use of Bayesian networks for causal modeling. They also draw on their own applied research to illustrate various applications of the technology.New to the Second EditionNew chapter on Bayesian network classifiersNew section on object-oriente

  20. Mechanism of artificial heart

    CERN Document Server

    Yamane, Takashi

    2016-01-01

    This book first describes medical devices in relation to regenerative medicine before turning to a more specific topic: artificial heart technologies. Not only the pump mechanisms but also the bearing, motor mechanisms, and materials are described, including expert information. Design methods are described to enhance hemocompatibility: main concerns are reduction of blood cell damage and protein break, as well as prevention of blood clotting. Regulatory science from R&D to clinical trials is also discussed to verify the safety and efficacy of the devices.

  1. Outer Belt Radial Transport Signatures in Drift Phase Structure - Case Studies

    Science.gov (United States)

    O'Brien, Paul; Green, Janet; Fennell, Joseph; Claudepierre, Seth; Roeder, James; Kwan, Betty; Mulligan Skov, Tamitha

    2016-07-01

    During geomagnetic storms, the Earth's outer radiation belt experiences enhanced radial transport. Different modes of radial transport have different temporal signatures in the particle phase-space density on timescales shorter than a drift period. We use such drift phase structure in time series particle flux observations to identify transport signatures of impulsive and oscillatory drift resonant transport. We perform multiple case studies of geomagnetic storms using particle flux taken near geostationary orbit. We estimate the radial diffusion coefficients from the drift phase structures. We show how these radial diffusion coefficients derived from particle data compare to transport coefficients deduced from wave observations.

  2. Test Particle Simulations of Inner Zone Proton Belt Loss During Geomagnetic Storms

    Science.gov (United States)

    Engel, M.; Kress, B. T.; Hudson, M. K.; Selesnick, R.

    2014-12-01

    The variability of the proton flux in the outer region of the inner radiation belt is of major interest. Solar proton events have been shown to be able to dramatically alter the flux in the L = 2 to 3 region, both causing increases and decreases. Current models are unable to accurately predict these changes when compared with observational data. In order to improve the models, the inductive electric field generated by the time changing ring current is added, so that proper radial inward and outward motion, due to the E x B drift, and the corresponding energy changes associated with the first adiabatic invariant are taken into account.

  3. Equilibria and Free Vibration of a Two-Pulley Belt-Driven System with Belt Bending Stiffness

    Directory of Open Access Journals (Sweden)

    Jieyu Ding

    2014-01-01

    Full Text Available Nonlinear equilibrium curvatures and free vibration characteristics of a two-pulley belt-driven system with belt bending stiffness and a one-way clutch are investigated. With nonlinear dynamical tension, the transverse vibrations of the translating belt spans and the rotation motions of the pulleys and the accessory shaft are coupled. Therefore, nonlinear piecewise discrete-continuous governing equations are established. Considering the bending stiffness of the translating belt spans, the belt spans are modeled as axially moving beams. The pattern of equilibria is a nontrivial solution. Furthermore, the nontrivial equilibriums of the dynamical system are numerically determined by using two different approaches. The governing equations of the vibration near the equilibrium solutions are derived by introducing a coordinate transform. The natural frequencies of the dynamical systems are studied by using the Galerkin method with various truncations and the differential and integral quadrature methods. Moreover, the convergence of the Galerkin truncation is investigated. Numerical results reveal that the study needs 16 terms after truncation in order to determine the free vibration characteristics of the pulley-belt system with the belt bending stiffness. Furthermore, the first five natural frequencies are very sensitive to the bending stiffness of the translating belt.

  4. Measurements of whistler-mode waves in the outer Van Allen belt: systematic analysis of 11 years of multicomponent data from the Cluster STAFF-SA instrument

    Czech Academy of Sciences Publication Activity Database

    Santolík, Ondřej; Macúšová, Eva; Kolmašová, Ivana; Cornilleau-Wehrlin, N.

    2013. [Radiation Belts Workshop: Comprehending, Specifying and Forecasting their Dynamics. 30.06.2013-03.07.2013, Santorini] Grant ostatní: FP7-MAARBLE(XE) 284520 Source of funding: R - rámcový projekt EK Institutional support: RVO:68378289 Keywords : whistler-mode waves * Cluster http://space-env.esa.int/indico/conferenceDisplay.py/abstractBook?confId=20

  5. Modelling radiation-induced phase changes in binary FeCu and ternary FeCuNi alloys using an artificial intelligence-based atomistic kinetic Monte Carlo approach

    International Nuclear Information System (INIS)

    We apply a novel atomistic kinetic Monte Carlo model, which includes local chemistry and relaxation effects when assessing the migration energy barriers of point defects, to the study of the microchemical evolution driven by vacancy diffusion in FeCu and FeCuNi alloys. These alloys are of importance for nuclear applications because Cu precipitation, enhanced by the presence of Ni, is one of the main causes of hardening and embrittlement in reactor pressure vessel steels used in existing nuclear power plants. Local chemistry and relaxation effects are introduced using artificial intelligence techniques, namely a conveniently trained artificial neural network, to calculate the migration energy barriers of vacancies as functions of the local atomic configuration. We prove, through a number of results, that the use of the neural network is fully equivalent to calculating the migration energy barriers on-the-fly, using computationally expensive methods such as nudged elastic bands with an interatomic potential. The use of the neural network makes the computational cost affordable, so that simulations of the same type as those hitherto carried out using heuristic formulas for the assessment of the energy barriers can now be performed, at the same computational cost, using more rigorously calculated barriers. This method opens the way to properly treating more complex problems, such as the case of self-interstitial cluster formation, in an atomistic kinetic Monte Carlo framework.

  6. Geometry, kinematics and evolution of the Tongbai orogenic belt

    Institute of Scientific and Technical Information of China (English)

    HUANG Shaoying; XU Bei; WANG Changqiu; ZHAN Sheng; DENG Rongjing

    2006-01-01

    The Tongbai orogenic belt (TOB) is composed of six tectonic units. From south to north these units are: Tongbai gneiss rise (TGR); Hongyihe-Luozhuang eclogite belt (HLE); Maopo-Hujiazhai igneous rock belt (MHI); Zhoujiawan flysch belt (ZFB); Yangzhuang greenschist belt (YGB); and Dongjiazhuang marble belt (DMB).The geometry and kinematic images of the TOB include: the antiformal structures caused by a later uplift process, the top-to-north ductile shear structure that related to a process that the ultrahigh pressure rocks are brought to surface, the top-to-south ductile shear thrust and the sinistrial shear structures related to a south-north direction compression, and the east-west direction fold structures in the upper crust. In the view of the multistage subduction-collision orogenic belt, according to the characters of petrology and its distribution, geometry, kinematics and structural chronology in these tectonic units, tectonic evolution of the TOB can be divided into four stages: oceanic crust subduction during 400-300 Ma, continental collision during 270-250 Ma, continental deep subduction and uplift during 250-205 Ma and doming deformation during 200-185 Ma.

  7. HERSCHEL-RESOLVED OUTER BELTS OF TWO-BELT DEBRIS DISKS AROUND A-TYPE STARS: HD 70313, HD 71722, HD 159492, AND F-TYPE: HD 104860

    International Nuclear Information System (INIS)

    We present dual-band Herschel/Photodetector Array Camera and Spectrometer imaging for four stars whose spectral energy distributions (SEDs) suggest two-ring disk architectures that mirror that of the asteroid-Kuiper Belt geometry of our own solar system. The Herschel observations at 100 μm spatially resolve the cold/outer-dust component for each star-disk system for the first time, finding evidence of planetesimals at >100 AU, i.e., a larger size than assumed from a simple blackbody fit to the SED. By breaking the degeneracy between the grain properties and the dust's radial location, the resolved images help constrain the dust grain-size distribution for each system. Three of the observed stars are A-type and one solar-type. On the basis of the combined Spitzer/IRS+MIPS (5-70 μm), the Herschel/PACS (100 and 160 μm) dataset, and under the assumption of idealized spherical grains, we find that the cold/outer belts of the three A-type stars are well fit with a mixed ice/rock composition rather than pure rocky grains, while the debris around the solar-type star is consistent with either rock or ice/rock grains. For the solar-type star HD 104860, we find that the minimum grain size is larger than expected from the threshold set by radiative blowout. The A-type stars HD 71722 and HD 159492, on the other hand, require minimum grain sizes that are smaller than blowout for inner- and outer-ring populations. In the absence of spectral features for ice, we find that the behavior of the continuum can help constrain the composition of the grains (of icy nature and not pure rocky material) given the Herschel-resolved locations of the cold/outer-dust belts

  8. Artificial organs: recent progress in artificial hearing and vision.

    Science.gov (United States)

    Ifukube, Tohru

    2009-01-01

    Artificial sensory organs are a prosthetic means of sending visual or auditory information to the brain by electrical stimulation of the optic or auditory nerves to assist visually impaired or hearing-impaired people. However, clinical application of artificial sensory organs, except for cochlear implants, is still a trial-and-error process. This is because how and where the information transmitted to the brain is processed is still unknown, and also because changes in brain function (plasticity) remain unknown, even though brain plasticity plays an important role in meaningful interpretation of new sensory stimuli. This article discusses some basic unresolved issues and potential solutions in the development of artificial sensory organs such as cochlear implants, brainstem implants, artificial vision, and artificial retinas. PMID:19330498

  9. The optimization of steelcord belt splices; Optimierung von Stahlseilgurtverbindungen

    Energy Technology Data Exchange (ETDEWEB)

    Hager, M. [Hannover Univ. (Germany); Keller, M. [ContiTech Transportbandsysteme GmbH, Northeim (Germany)

    2002-03-01

    Belt-conveyors have proven themselves for the continuous bulk conveying under technical and economic points of view for a long time. For long belt conveyors and big mass flows, steelcord conveyor belts technologically represent the state of the art. In a steelcord belt splice, the tensile force between the spliced belt ends is transmitted almost completely by locally differing shear forces in the rubber of the elastomer composite construction. Under the dynamically swelling load, to which the belt is exposed in operation, the splices represent the weakest part of a conveyor belt. In experimental examinations of this paper it was found, that the characteristic behavior of the material of the elastomer and the constructive design influences distortion behavior under force of steelcord belt test samples. As most important parameter of the compound design, the filler proves itself as the strongest influence on the dynamic shear modulus, which characterizes the non linear dynamic stiffness of the elastomer. The filling degree and the filler composition influence the degree of non linearity of the dynamic shear modulus and its complex components. On the basis of the results of the experimental examinations, an approximation model of the non linear dynamic shear modulus was employed, with which it is possible, to characterize the non linear, amplitude dependent material behavior of the examined elastomer. In the scope of this paper, a program system was developed on basis of the finite element method, that allows the arithmetical simulation of the force flow in steelcord belt splices and in highly stressed areas of the splices. (orig.)

  10. Radiation, health and society

    International Nuclear Information System (INIS)

    Experience from over one hundred years of working with radiation and follow-up studies of hundreds of thousands of workers has not revealed health hazards caused by normal exposure to natural radiation or to artificial radiation below the limits prescribed by ICRP. For the public, dose limits are only a fraction of those specified for occupationally exposed workers. While many people feel anxiety about the possibility of accidents in nuclear establishments and the short and long term effects on their health and on the health of their descendants, the risks from radiation must be seen in perspective. Human activities have added some artificial radioactive substances to the environment, but on the whole, that amount is far slighter than most people realize, and so slight that its impact on health can only be characterized as minimal

  11. The Space Radiation Environment

    Science.gov (United States)

    Bourdarie, Sebastien; Xapsos, Michael A.

    2008-01-01

    The effects of the space radiation environment on spacecraft systems and instruments are significant design considerations for space missions. Astronaut exposure is a serious concern for manned missions. In order to meet these challenges and have reliable, cost-effective designs, the radiation environment must be understood and accurately modeled. The nature of the environment varies greatly between low earth orbits, higher earth orbits and interplanetary space. There are both short-term and long-term variations with the phase of the solar cycle. In this paper we concentrate mainly on charged particle radiations. Descriptions of the radiation belts and particles of solar and cosmic origin are reviewed. An overview of the traditional models is presented accompanied by their application areas and limitations. This is followed by discussion of some recent model developments.

  12. Detection of Small Kuiper Belt Objects by Stellar Occultations

    OpenAIRE

    Stevenson, R

    2007-01-01

    Knowledge of the Kuiper Belt is currently limited to those objects that can be detected directly. Objects with diameters less than $\\sim$10km reflect too little light to be detected. These smaller bodies could contain most of the mass in the Kuiper Belt while the abundance of these bodies may constrain the distribution of mass. The overall size distribution of bodies within the Kuiper Belt can also be inferred from the relative abundances of sub-km and larger bodies. Stellar occultations are ...

  13. Into the Kuiper Belt: New Horizons Post-Pluto

    Science.gov (United States)

    Harrison Parker, Alex; Spencer, John; Benecchi, Susan; Binzel, Richard; Borncamp, David; Buie, Marc; Fuentes, Cesar; Gwyn, Stephen; Kavelaars, JJ; Noll, Keith; Petit, Jean-Marc; Porter, Simon; Showalter, Mark; Stern, S. Alan; Sterner, Ray; Tholen, David; Verbiscer, Anne; Weaver, Hal; Zangari, Amanda

    2015-11-01

    New Horizons is now beyond Pluto and flying deeper into the Kuiper Belt. In the summer of 2014, a Hubble Space Telescope Large Program identified two candidate Cold Classical Kuiper Belt Objects (KBOs) that were within reach of New Horizons' remaining fuel budget. Here we present the selection of the Kuiper Belt flyby target for New Horizons' post-Pluto mission, our state of knowledge regarding this target and the potential 2019 flyby, the status of New Horizons' targeting maneuver, and prospects for near-future long-range observations of other KBOs.

  14. Cooperative quasi-Cherenkov radiation

    CERN Document Server

    Anishchenko, S V

    2014-01-01

    We study the features of cooperative parametric (quasi-Cherenkov) radiation arising when initially unmodulated electron (positron) bunches pass through a crystal (natural or artificial) under the conditions of dynamical diffraction of electromagnetic waves in the presence of shot noise. A detailed numerical analysis is given for cooperative THz radiation in artificial crystals. The radiation intensity above 200~MW$/$cm$^2$ is obtained in simulations. In two- and three-wave diffraction cases, the peak intensity of cooperative radiation emitted at small and large angles to particle velocity is investigated as a function of the particle number in an electron bunch. The peak radiation intensity appeared to increase monotonically until saturation is achieved. At saturation, the shot noise causes strong fluctuations in the intensity of cooperative parametric radiation. It is shown that the duration of radiation pulses can be much longer than the particle flight time through the crystal. This enables a thorough expe...

  15. Environmental radioactivity and radiation exposure

    International Nuclear Information System (INIS)

    In 1977 population exposure in the Federal Republic of Germany has not changed as compared to the previous years. The main share of the total exposure, nearly two thirds, is attributed to natural radioactive substances and cosmic radiation. The largest part (around 85%) of the artificial radiation exposure is caused by X-ray diagnostics. In comparison to this, radiation exposure from application of ionizing radiation in medical therapy, use of radioactive material in research and technology, or from nuclear facilities is small. As in the years before, population exposure caused by nuclear power plants and other nuclear facilities is distinctly less than 1% of the natural radiation exposure. This is also true for the average radiation exposure within a radius of 3 km around nuclear facilities. On the whole, the report makes clear that the total amount of artificial population exposure will substantially decrease only if one succeeds in reducing the high contribution to the radiation exposure caused by medical measures. (orig.)

  16. Artificial sweeteners - a review.

    Science.gov (United States)

    Chattopadhyay, Sanchari; Raychaudhuri, Utpal; Chakraborty, Runu

    2014-04-01

    Now a days sugar free food are very much popular because of their less calorie content. So food industry uses various artificial sweeteners which are low in calorie content instead of high calorie sugar. U.S. Food and Drug Administration has approved aspartame, acesulfame-k, neotame, cyclamate and alitame for use as per acceptable daily intake (ADI) value. But till date, breakdown products of these sweeteners have controversial health and metabolic effects. On the other hand, rare sugars are monosaccharides and have no known health effects because it does not metabolize in our body, but shows same sweet taste and bulk property as sugar. Rare sugars have no such ADI value and are mainly produced by using bioreactor and so inspite of high demand, rare sugars cannot be produced in the desired quantities. PMID:24741154

  17. Artificial Immune Systems (2010)

    CERN Document Server

    Greensmith, Julie; Aickelin, Uwe

    2010-01-01

    The human immune system has numerous properties that make it ripe for exploitation in the computational domain, such as robustness and fault tolerance, and many different algorithms, collectively termed Artificial Immune Systems (AIS), have been inspired by it. Two generations of AIS are currently in use, with the first generation relying on simplified immune models and the second generation utilising interdisciplinary collaboration to develop a deeper understanding of the immune system and hence produce more complex models. Both generations of algorithms have been successfully applied to a variety of problems, including anomaly detection, pattern recognition, optimisation and robotics. In this chapter an overview of AIS is presented, its evolution is discussed, and it is shown that the diversification of the field is linked to the diversity of the immune system itself, leading to a number of algorithms as opposed to one archetypal system. Two case studies are also presented to help provide insight into the m...

  18. A Primer on Artificial Intelligence.

    Science.gov (United States)

    Leal, Ralph A.

    A survey of literature on recent advances in the field of artificial intelligence provides a comprehensive introduction to this field for the non-technical reader. Important areas covered are: (1) definitions, (2) the brain and thinking, (3) heuristic search, and (4) programing languages used in the research of artificial intelligence. Some…

  19. Generalized Adaptive Artificial Neural Networks

    Science.gov (United States)

    Tawel, Raoul

    1993-01-01

    Mathematical model of supervised learning by artificial neural network provides for simultaneous adjustments of both temperatures of neurons and synaptic weights, and includes feedback as well as feedforward synaptic connections. Extension of mathematical model described in "Adaptive Neurons For Artificial Neural Networks" (NPO-17803). Dynamics of neural network represented in new model by less-restrictive continuous formalism.

  20. Sucrose compared with artificial sweeteners

    DEFF Research Database (Denmark)

    Sørensen, Lone Brinkmann; Vasilaras, Tatjana H; Astrup, Arne;

    2014-01-01

    There is a lack of appetite studies in free-living subjects supplying the habitual diet with either sucrose or artificially sweetened beverages and foods. Furthermore, the focus of artificial sweeteners has only been on the energy intake (EI) side of the energy-balance equation. The data are from a...

  1. Environmental radiation

    International Nuclear Information System (INIS)

    The types of ionizing radiations from the atomic nucleus are explained, such as the beams alpha, beta and gamma. The definitions of spectrometry and nuclear traces have been included.The study presents two researches realized in Costa Rica on the radioactive nuclear and artificial elements in the environment. The first shown is the analysis of coastal sediments where explains which are radioactive artificial isotopes and the pollution that occurs in food, coastal sediments, fertilizers, the soil, the water and the air. Within the analysis techniques are the gamma spectrometry, alpha spectrometry and nuclear strokes. Among the conclusions of this initial investigation is shown that at Punta Leona descendants of Uranium and Thorium present lower concentrations in relation to the gulf and its variations are not important. In the following study the radon gas is analyzed in the human environment where is determined that it is the second generator that causes cancer in lungs after the tobacco. This work indicates that the doses come from natural and artificial sources of radiation for the public are a whole of 2.7 mSv/year, information provided by the UNSCEAR, 2000. The radon gas is inert and radioactive of atomic number 86, includes 23 isotopes and 3 natural isotopes. The radon is everywhere, as are houses and buildings, in Costa Rica it is located in old homes with little ventilation. It describes the equipment used for the detection of radon gas in the environment. Within the conclusions radon gas is concentrated in confined spaces which can be harmful to health. It is determined that enough ventilation in places of high concentrations of radon is important. Finally it is recommended to monitor the sites where can be detected high concentrations of radon and that they have important influx of people

  2. Radiation protection in nuclear reactors

    International Nuclear Information System (INIS)

    Full text: People are exposed to ionizing radiation in many different forms: cosmic rays that penetrate earth atmosphere or radiation from soil and mineral resources are natural forms of ionizing radiation. Other forms are produced artificially using radioactive materials for various beneficial applications in medicine, industry and other fields. The greatest concerns about ionizing radiation are tied to its potential health effects and a system of radiation protection has been developed to protect people from harmful radiation. The promotion of radiation protection is one of the International Atomic Energy Agency main activities. Radiation protection concerns the protection of workers, members of public, and patients undergoing diagnosis and therapy against the harmful effects of ionizing radiation. The report covers the responsibility of radiation protection officer in Egypt Second Research Reactor (ETRR-2) in Inshas - Egypt, also presents the protection against ionizing radiation from external sources, including types of radiation, sources of radiation (natural - artificial), and measuring units of dose equivalent rate. Also covers the biological effects of ionizing radiation, personal monitoring and radiation survey instruments and safe transport of radioactive materials. The report describes the Egypt Second Research Reactor (ETRR-2), the survey instruments used, also presents the results obtained and gave a relations between different categories of data. (author)

  3. Soft computing in artificial intelligence

    CERN Document Server

    Matson, Eric

    2014-01-01

    This book explores the concept of artificial intelligence based on knowledge-based algorithms. Given the current hardware and software technologies and artificial intelligence theories, we can think of how efficient to provide a solution, how best to implement a model and how successful to achieve it. This edition provides readers with the most recent progress and novel solutions in artificial intelligence. This book aims at presenting the research results and solutions of applications in relevance with artificial intelligence technologies. We propose to researchers and practitioners some methods to advance the intelligent systems and apply artificial intelligence to specific or general purpose. This book consists of 13 contributions that feature fuzzy (r, s)-minimal pre- and β-open sets, handling big coocurrence matrices, Xie-Beni-type fuzzy cluster validation, fuzzy c-regression models, combination of genetic algorithm and ant colony optimization, building expert system, fuzzy logic and neural network, ind...

  4. Beyond AI: Artificial Dreams Conference

    CERN Document Server

    Zackova, Eva; Kelemen, Jozef; Beyond Artificial Intelligence : The Disappearing Human-Machine Divide

    2015-01-01

    This book is an edited collection of chapters based on the papers presented at the conference “Beyond AI: Artificial Dreams” held in Pilsen in November 2012. The aim of the conference was to question deep-rooted ideas of artificial intelligence and cast critical reflection on methods standing at its foundations.  Artificial Dreams epitomize our controversial quest for non-biological intelligence, and therefore the contributors of this book tried to fully exploit such a controversy in their respective chapters, which resulted in an interdisciplinary dialogue between experts from engineering, natural sciences and humanities.   While pursuing the Artificial Dreams, it has become clear that it is still more and more difficult to draw a clear divide between human and machine. And therefore this book tries to portrait such an image of what lies beyond artificial intelligence: we can see the disappearing human-machine divide, a very important phenomenon of nowadays technological society, the phenomenon which i...

  5. Geochemical ways of artificial radionuclide migration in biosphere

    International Nuclear Information System (INIS)

    This collection presents abstracts of papers on the following subjects: organization and methodology of research and developments on creation of combined medium- and largescale landscape-geochemical and radioecological maps for territories contaminated by radionuclides; typological and space features of distribution of artificial radionuclides and regularities of their migration, the radionuclides being entered the biosphere during accidents at NPPs; forms of artificial radionuclides in biosphere after the NPP accidents; simulation of primary entering and secondary migration of radionuclides in biosphere; methodology of organization and conducting radiogeochemical monitoring of biosphere; new methods and means for radiation monitoring of the environment

  6. MACRO MODEL OF SEAT BELT USE BY CAR DRIVERS AND PASSENGERS

    Directory of Open Access Journals (Sweden)

    Kazimierz JAMROZ

    2013-12-01

    Full Text Available The article presents some problems of seat belt use by car drivers and passengers. It looks in particular at seat belt use and effectiveness in selected countries. Next, factors of seat belt use are presented and methodology of model development. A macro model of seat belt use is presented based on data from around fifty countries from different continents.

  7. Psoriasis and ultraviolet radiation

    International Nuclear Information System (INIS)

    Prevention and detection screening programs as a public health service in curtailing the ever-increasing incidence of all forms of skin cancer are reviewed. The effect of solar and artificial ultraviolet radiation on the general population and persons with psoriasis is examined. 54 refs

  8. Geochronologic studies in the Grants mineral belt

    International Nuclear Information System (INIS)

    Geologic observation coupled with radiometric age dating can be used to assess ages of ore formation and, in some cases, ages of sedimentation in the Grants mineral belt. Rb-Sr studies indicate the earliest mineralization is trend ore at Ambrosia Lake and Smith Lake, dated at 139 +- 9.5 m.y. This date is similar to that for barren-rock montmorillonite from the Jackpile sandstone (Late Jurassic): 142 +- 14 m.y.; it may be used, with caution, to indicate the minimum age of sedimentation for the Morrison Formation. Geologic evidence indicates epigenetic rather than syngenetic ore formation. Barren-rock montmorillonites from Ambrosia Lake yield a poorly defined isochron of 132 +- 26 m.y. Early formed ore at the Jackpile-Paguate mine, Laguna district, was remobilized and reprecipitated at 113 +- 7 m.y. This date is older than the range of dates for the Dakota Formation (Cretaceous) and Mancos Shale. The 113 +- 7 m.y. mid-Cretaceous date for the Jackpile-Paguate ore is consistent with geologic evidence; geologic control suggests that other ore deposits are post-Late Jurassic but pre-Dakota Formation. Based on geologic evidence, mineralization in the Dakota Formation is thought to be very young. Laramide mineralization (60 to 70 m.y.) is evidenced by the presence of some stack ore. At least one uranium deposit, located partly in oxidized ground at the main redox front of the Grants mineral belt, may represent Tertiary mineralization; the clay-mineral Rb-Sr systematics of this deposit have been severely perturbed. Younger mineralization is indicated by U-Pb dates on uranophane (9 to 10 m.y.), and Pleistocene mineralization is noted for some ore. U-Pb dates of U4+ -rich ore minerals cluster between 80 and 100 m.y., although some are as old as 140 to 150 m.y. K-Ar dates on clay minerals range from 49 to 138 m.y. The reasons for this scatter are not known, although loss of radiogenic 40Ar due to burial is probable

  9. Environmental radiation and exposure to radiation

    International Nuclear Information System (INIS)

    Compared to 1977 the exposure to radiation of the population of the Federal Republic of Germany from both natural and artificial radiation sources has not greatly charged. The amin part of exposure to natural radiation is caused by environmental radiation and by the absorption of naturally radioactive substances into the body. Artificial exposure to radiation of the population is essentially caused by the use of ionizing rays and radioactive substances in medicine. When radioactive materials are released from nuclear facilities the exposure to radiation of the population is only very slightly increased. The real exposure to radiation of individual people can even in the worst affected places, have been at most fractions of a millirem. The exposure to radiation in the worst afected places in the area of a hard-coal power station is higher than that coming from a nuclear power station of the same capacity. The summation of all contributions to the exposure of radiation by nuclear facilities to the population led in 1978 in the Federal Republic of Germany to a genetically significant dose of clearly less than 1 millerem per year. The medium-ranged exposure to radiation by external radiation effects through professional work was in 1978 at 80 millirems. No difference to 1977. The contribution of radionuclide from the fallout coming from nuclear-weapon tests and which has been deposited in the soil, to the whole-body dose for 1978 applies the same as the genetically significant dose of the population with less than 1 millirem. (orig./HP)

  10. Archaean greenstone belt tectonism and basin development: some insights from the Barberton and Pietersburg greenstone belts, Kaapvaal Craton, South Africa

    Science.gov (United States)

    de Wit, Maarten J.

    The sediments in two of South Africa's major Archaean greenstone belts, the Barberton and Pietersburg greenstone belts, span an age range of some 800 million years. Both greenstone belts represent remnants of extensive fold and thrust belts with complex, but different polyphase tectonic histories. The oldest sediments were deposited between circa 3470 and 3490 M.a. on oceanic like crust preserved in the Barberton belt, possibly at the same time as sedimentation on similar oceanic crust preserved in the Pietersburg belt. Thereafter, the geologic evolution of these two belts diverged considerably. In the Barberton belt, there is clear evidence that the oceanic crust and sediments were obducted onto an intra-arc basin environment within 50 million years of its formation. The sequence was later further imbricated by northwest directed thrust stacking between 3300-3200 M.a. Basin development during both periods of thrusting took place in close proximity to active "calc-alkaline" arc systems. Deformation of the sediments within these basins took place while the same sediments were being deposited. Sedimentation took place predominantly in subaqueous environments, ranging from submarine mid-fans below the photic zone to tidal flats and deltaic plains. The sediments represent a polyhistory successor-type basin: early basins developed along a complex subduction related plate boundary; these basins later evolved into foreland depositories along and within collisional environments of an accretionary orogen. Late in the history of the Barberton greenstone belt (circa 3100 M.a.), the rocks were in places thermally reactivated and probably subjected to extensional processes; these processes overlapped in time with the main episodes of economic gold mineralization, and are of "early Witwatersrand-basin" age. The oceanic-like crust (including associated sediments) preserved in the Pietersburg belt was not significantly deformed until at least 500 million years after its formation

  11. An Icy Kuiper-Belt Around the Young Solar-Type Star HD 181327

    Science.gov (United States)

    Lebreton, J.; Augereau, J.-C.; Thi, W.-F.; Roberge, A.; Donaldson, J.; Schneider, G.; Maddison, S. T.; Menard, F.; Riviere-Marichalar, P.; Mathews, G. S.; Kamp, I.; Pinte, C.; Dent, W. R. F.; Barrado, D.; Duchene, G.; Gonzalez, J.-F.; Grady, C. A.; Meeus, G.; Pantin, E.; Williams, J. P.; Woitke, P.

    2011-01-01

    HD 181327 is a young Main Sequence F5/F6 V star belonging to the Beta Pictoris moving group (age approx 12 Myr). It harbors an optically thin belt of circumstellar material at approx90 AU, presumed to result from collisions in a populat.ion of unseen planetesimals. Aims. We aim to study the dust properties in the belt in great details, and to constrain the gas-to-dust ratio. Methods. We obtained far-IR photometric observations of HD 181327 with the PACS instrument onboard the Herschel Space Observatory, complemented by new 3.2 nun observations carried with the ATCA array. The geometry of the belt is constrained with newly reduced HST /NICMOS scattered light images that break the degeneracy between the disk geometry and the dust properties. We then use the radiative transfer code GRaTer to compute a large grid of dust models, and we apply a Bayesian inference method to identify the grain models that best reproduce the SED. We attempt to detect the oxygen and ionized carbon fine-structure lines with Herschel/PACS spectroscopy, providing observables to our photochemical code ProDiMo. Results. The HST observations confirm that the dust is confined in a narrow belt. The continuum is detected with Herschel/PACS completing nicely the SED in the far-infrared. The disk is marginally resolved with both PACS and ATCA. A medium integration of the gas spectral lines only provides upper limits on the [OI] and [CII] line fluxes. We show that the HD 181327 dust disk consists of micron-sized grains of porous amorphous silicates and carbonaceous material surrounded by an import.ant layer of ice for a total dust mass of approx 0.05 stellar Mass. We discuss evidences that the grains consists of fluffy aggregates. The upper limits on the gas atomic lines do not provide unambiguous constraints: only if the PAH abundance is high, the gas mass must be lower than approx 17 Stellar Mass Conclusions. Despite the weak constraints on the gas disk, the age of HD 181327 and the properties of the

  12. Face-Saving Devices: Seat Belts and Air Bags

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_160032.html Face-Saving Devices: Seat Belts and Air Bags Using ... 11 percent) suffered facial fractures -- nasal and mid-face fractures most often. Those most likely to suffer ...

  13. CRED REA Fish Team Belt Transect Survey at Laysan 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 3 sites at Laysan in the...

  14. Back belts in occupational setting: what are the evidences?

    Directory of Open Access Journals (Sweden)

    João Marcos Bernardes

    2012-01-01

    Full Text Available Although, widely used the mechanisms of action and the effectiveness of back belts in the prevention of occupational low back disorders remains uncertain, generating controversy about its use. Therefore, the purpose of this study was to do a critical literature review about back belts use in the prevention of occupational low back pain in the occupational setting. In order to do that, a bibliographic research in the following data basis: Medline, SciELO and LILACS was conducted. There is evidence that back belts use reduces spine range of motion, however the studies about intra-abdominal pressure and muscle activity presented contradictory results, as the epidemiologic studies, not allowing the recommendation of its use in the prevention of occupational low back pain. Based on this literature review it is suggested therefore, the implementation of new studies, to confirm or not the effectiveness of back belts as personal protective equipment, in the prevention of occupational low back disorders.

  15. Cenozoic intracontinental deformation of the Kopeh Dagh Belt, Northeastern Iran

    Science.gov (United States)

    Chu, Yang; Wan, Bo; Chen, Ling; Talebian, Morteza

    2016-04-01

    Compressional intracontinental orogens represent large tectonic zones far from plate boundaries. Since intracontinental mountain belts cannot be framed in the conventional plate tectonics theory, several hypotheses have been proposed to account for the formations of these mountain belts. The far-field effect of collision/subduction at plate margins is now well accepted for the origin and evolution of the intracontinental crust thickening, as exemplified by the Miocene tectonics of central Asia. In northern Iran, the Binalud-Alborz mountain belt witnessed the Triassic tectonothermal events (Cimmerian orogeny), which are interpreted as the result of the Paleotethys Ocean closure between the Eurasia and Central Iran blocks. The Kopeh Dagh Belt, located to the north of the Binalud-Alborz Belt, has experienced two significant tectonic phases: (1) Jurassic to Eocene rifting with more than 7 km of sediments; and (2) Late Eocene-Early Oligocene to Quaternary continuous compression. Due to the high seismicity, deformation associated with earthquakes has received more and more attention; however, the deformation pattern and architecture of this range remain poorly understood. Detailed field observations on the Cenozoic deformation indicate that the Kopeh Dagh Belt can be divided into a western zone and an eastern zone, separated by a series of dextral strike-slip faults, i.e. the Bakharden-Quchan Fault System. The eastern zone characterized by km-scale box-fold structures, associated with southwest-dipping reverse faults and top-to-the NE kinematics. In contrast, the western zone shows top-to-the SW kinematics, and the deformation intensifies from NE to SW. In the northern part of this zone, large-scale asymmetrical anticlines exhibit SW-directed vergence with subordinate thrusts and folds, whereas symmetrical anticlines are observed in the southern part. In regard to its tectonic feature, the Kopeh Dagh Belt is a typical Cenozoic intracontinental belt without ophiolites or

  16. SPECIFIC RESISTANCE AND SPECIFIC INTENSITY OF BELT SANDING OF WOOD

    Directory of Open Access Journals (Sweden)

    Boleslaw Porankiewicz

    2010-06-01

    Full Text Available This paper examines and discusses the specific belt sanding resistance K (N·cm-2 and specific belt sanding intensity SI (g·cm-2·min-1, for wood of Pinus sylvestris L., Picea abies L., Quercus robra L., Acer pseudoplatanus L., Alnus glutinosa Gaertn., and Populus Nigra L., by different sanding pressure pS, different sanding grit NG number, and different wood grain angles Phi(v.

  17. Promoting automobile safety belt use by young children.

    OpenAIRE

    Sowers-Hoag, K M; Thyer, B A; Bailey, J S

    1987-01-01

    A program using behavioral practice, assertiveness training, and social and contrived reinforcers was developed to establish and maintain automobile safety belt use by young children. Sixteen children (ages 4.8 to 7 years) who never used their safety belts during a 5-day preexperimental observation period were randomly assigned to two groups of eight each. A multiple baseline design across groups was used to evaluate the effectiveness of the training program. During the 8-day baseline period ...

  18. Back belts in occupational setting: what are the evidences?

    OpenAIRE

    João Marcos Bernardes; Antonio Renato Pereira Moro

    2012-01-01

    Although, widely used the mechanisms of action and the effectiveness of back belts in the prevention of occupational low back disorders remains uncertain, generating controversy about its use. Therefore, the purpose of this study was to do a critical literature review about back belts use in the prevention of occupational low back pain in the occupational setting. In order to do that, a bibliographic research in the following data basis: Medline, SciELO and LILACS was conducted. There is evid...

  19. Tribological Properties of Metal V-Belt Type CVT Lubricant

    OpenAIRE

    Keiichi Narita

    2012-01-01

    The priority for lubricant performance for metal V-belt-type CVT (B-CVTFs) should be the improvement of transmittable torque capacity between the belt and pulley plus excellent antishudder properties for lockup clutch used in B-CVTs. This study intends to investigate the effect of lubricant additives for improving these performances of B-CVTs. In addition, surface analysis techniques were utilized to gain a novel insight into the chemical composites and morphology of the tribofilms. As a resu...

  20. Design of MGA trajectories for main belt asteroid

    Institute of Scientific and Technical Information of China (English)

    崔祜涛; 乔栋; 崔平远; 栾恩杰

    2003-01-01

    Asteroid exploration is one of the most sophisticated missions currently being investigated. Gravityassist trajectories have proven valuable in interplanetary missions such as the Pioneer, Voyager and Galileo. In this paper, we design interplanetary trajectory for main belt asteroid exploration mission with the Mars gravityassist (MGA) using "pork chop" plots and patched-conic theory and give some initial valuable trajectory parameters on main belt asteroid exploration mission with MGA.

  1. The artificial leaf.

    Science.gov (United States)

    Nocera, Daniel G

    2012-05-15

    To convert the energy of sunlight into chemical energy, the leaf splits water via the photosynthetic process to produce molecular oxygen and hydrogen, which is in a form of separated protons and electrons. The primary steps of natural photosynthesis involve the absorption of sunlight and its conversion into spatially separated electron-hole pairs. The holes of this wireless current are captured by the oxygen evolving complex (OEC) of photosystem II (PSII) to oxidize water to oxygen. The electrons and protons produced as a byproduct of the OEC reaction are captured by ferrodoxin of photosystem I. With the aid of ferrodoxin-NADP(+) reductase, they are used to produce hydrogen in the form of NADPH. For a synthetic material to realize the solar energy conversion function of the leaf, the light-absorbing material must capture a solar photon to generate a wireless current that is harnessed by catalysts, which drive the four electron/hole fuel-forming water-splitting reaction under benign conditions and under 1 sun (100 mW/cm(2)) illumination. This Account describes the construction of an artificial leaf comprising earth-abundant elements by interfacing a triple junction, amorphous silicon photovoltaic with hydrogen- and oxygen-evolving catalysts made from a ternary alloy (NiMoZn) and a cobalt-phosphate cluster (Co-OEC), respectively. The latter captures the structural and functional attributes of the PSII-OEC. Similar to the PSII-OEC, the Co-OEC self-assembles upon oxidation of an earth-abundant metal ion from 2+ to 3+, may operate in natural water at room temperature, and is self-healing. The Co-OEC also activates H(2)O by a proton-coupled electron transfer mechanism in which the Co-OEC is increased by four hole equivalents akin to the S-state pumping of the Kok cycle of PSII. X-ray absorption spectroscopy studies have established that the Co-OEC is a structural relative of Mn(3)CaO(4)-Mn cubane of the PSII-OEC, where Co replaces Mn and the cubane is extended in a

  2. Occultation Searches for Kuiper Belt Objects

    CERN Document Server

    Cooray, A R; Cooray, Asantha; Farmer, Alison J.

    2003-01-01

    The occultation of background stellar sources by foreground Kuiper Belt Objects (KBOs) can be used to survey physical properties of the KBO population. We discuss statistics related to a KBO occultation survey, such as the event duration distribution, and suggest that occultation searches can be effectively used to probe the KBO size distribution below 10 km. In particular, we suggest that occultation surveys may be best suited to search for a turnover radius in the KBO size distribution due to collisions between small-size objects. For occultation surveys that monitor stellar sources near the ecliptic over a few square degrees, with time sampling intervals of order 0.1 sec and sensitivity to flux variations of a few percent or more, a turnover radius between 0.1 and 1.0 km can be probed. While occultation surveys will probe the low-radius limit and imaging surveys will detect KBOs of size 100 km or more, statistics of objects with sizes in the intermediate range of around 1 km to 100 km will likely remain un...

  3. Detecting Mass Loss in Main Belt Asteroids

    Science.gov (United States)

    Sandberg, Erik; Rajagopal, Jayadev; Ridgway, Susan E.; Kotulla, Ralf C.; Valdes, Francisco; Allen, Lori

    2016-01-01

    Sandberg, E., Rajagopal, J., Ridgway, S.E, Kotulla, R., Valdes, F., Allen, L.The Dark Energy Camera (DECam) on the 4m Blanco telescope at the Cerro Tololo Inter-American Observatory (CTIO) is being used for a survey of Near Earth Objects (NEOs). Here we attempt to identify mass loss in main belt asteroids (MBAs) from these data. A primary motivation is to understand the role that asteroids may play in supplying dust and gas for debris disks. This work focuses on finding methods to automatically pick out asteroids that have qualities indicating possible mass loss. Two methods were chosen: looking for flux above a certain threshold in the asteroid's radial profile, and comparing its PSF to that of a point source. After sifting through 490 asteroids, several have passed these tests and should be followed up with a more rigorous analysis.Sandberg was supported by the NOAO/KPNO Research Experience for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program (AST-1262829)

  4. Scheelite distribution a long of amphibolitic belt from greenstone belt Barbacena, Minas Gerais, Brazil

    International Nuclear Information System (INIS)

    In the middle southern portion of the Minas Gerais state a 60 Km long and 12 Km wide tungsten belt was discovered, and related to the amphibolitic rocks of the Barbacena Greenstone. Tungsten, present as scheelite, is associated with amphibolites, amphibole schists and amphibole gneisses, with chemical characteristics indicating an igneous origin. Chemical analyses on pan concentrates by I.C.P. showed high values on lead, tin, yttrium, lanthanum, cerium and zirconium, and average values for zinc and copper. The scheelite mineralization is probably strata bound and has a possible submarine exhalative origin. (author)

  5. natural or artificial diets

    Directory of Open Access Journals (Sweden)

    A. O. Meyer-Willerer

    2005-01-01

    Full Text Available Se probaron alimentos artificiales y naturales con larva de camarón (Litopenaeus vannamei cultivados en diferentes recipientes. Estos fueron ocho frascos cónicos con 15L, ocho acuarios con 50L y como grupo control, seis tanques de fibra de vidrio con 1500L; todos con agua marina fresca y filtrada. La densidad inicial en todos los recipientes fue de 70 nauplios/L. Aquellos en frascos y acuarios recibieron ya sea dieta natural o artificial. El grupo control fue cultivado con dieta natural en los tanques grandes que utilizan los laboratorios para la producción masiva de postlarvas. El principal producto de excreción de larva de camarón es el ión amonio, que es tóxico cuando está presente en concentraciones elevadas. Se determinó diariamente con el método colorimétrico del indofenol. Los resultados muestran diferencias en la concentración del ión amonio y en la sobrevivencia de larvas entre las diferentes dietas y también entre los diferentes recipientes. En aquellos con volúmenes pequeños comparados con los grandes, se presentó mayor concentración de amonio (500 a 750µg/L, en aquellos con dietas naturales, debido a que este ión sirve de fertilizante a las algas adicionadas, necesitando efectuar recambios diarios de agua posteriores al noveno día de cultivo para mantener este ión a una concentración subletal. Se obtuvo una baja cosecha de postlarvas (menor a 15% con el alimento artificial larvario, debido a la presencia de protozoarios, alimentándose con el producto comercial precipitado en el fondo de los frascos o acuarios. Los acuarios con larvas alimentadas con dieta natural también mostraron concentraciones subletales de amonio al noveno día; sin embargo, la sobrevivencia fue cuatro veces mayor que con dietas artificiales. Los tanques control con dietas naturales presentaron tasas de sobrevivencia (70 ± 5% similares a la reportada por otros laboratorios.

  6. On-conveyor belt determination of ash in coal

    International Nuclear Information System (INIS)

    A laboratory feasibility study has been carried out on new and advanced neutron and gamma-ray analysis systems for the direct on-conveyor belt analysis of ash in coal without the need for sample by-lines. Such an analysis system could deliver the combined advantages of a direct on-conveyor configuration with new and accurate analysis techniques. An industry survey of 18 coal companies carried out in early 1996 indicated that accurate on-belt ash analysis is of the highest priority. Subsequent laboratory work has focussed on the investigation of methods with the potential for improving the accuracy of ash content measurement relative to existing on-belt ash analysers, the most widely-used of which are based on dual energy gamma-ray transmission (DUET), which is sensitive to variations in ash composition. The current work indicates that on-belt neutron/gamma-ray techniques combined with advanced spectral analysis techniques show promise for development into an on-belt ash analysis system which is significantly less sensitive to composition changes than DUET and which analyses a much larger proportion of coal on the belt, thus eliminating some key sources of analysis error

  7. Forming the Cold Classical Kuiper Belt in a light Disk

    CERN Document Server

    Shannon, Andrew; Lithwick, Yoram

    2015-01-01

    Large Kuiper Belt Objects are conventionally thought to have formed out of a massive planetesimal belt that is a few thousand times its current mass. Such a picture, however, is incompatible with multiple lines of evidence. Here, we present a new model for the conglomeration of Cold Classical Kuiper belt objects, out of a solid belt only a few times its current mass, or a few percent of the solid density in a Minimum Mass Solar Nebula. This is made possible by depositing most of the primordial mass in grains of size centimetre or smaller. These grains collide frequently and maintain a dynamically cold belt out of which large bodies grow efficiently: an order-unity fraction of the solid mass can be converted into large bodies, in contrast to the ~0.1% efficiency in conventional models. Such a light belt may represent the true outer edge of the Solar system, and it may have effectively halted the outward migration of Neptune. In addition to the high efficiency, our model can also produce a mass spectrum that pe...

  8. Artificial frustrated spin systems

    Science.gov (United States)

    Perrin, Y.; Chioar, I. A.; Nguyen, V. D.; Lacour, D.; Hehn, M.; Montaigne, F.; Canals, B.; Rougemaille, N.

    2015-09-01

    Complex architectures of nanostructures are routinely elaborated using bottom-up or nanofabrication processes. This technological capability allows scientists to engineer materials with properties that do not exist in nature, but also to manufacture model systems to explore fundamental issues in condensed matter physics. Two-dimensional frustrated arrays of magnetic nanostructures are one class of systems for which theoretical predictions can be tested experimentally. These systems have been the subject of intense research in the last few years and allowed the investigation of a rich physics and fascinating phenomena, such as the exploration of the extensively degenerate ground-state manifolds of spin ice systems, the evidence of new magnetic phases in purely two-dimensional lattices, and the observation of pseudoexcitations involving classical analogues of magnetic monopoles. We show here, experimentally and theoretically, that simple magnetic geometries can lead to unconventional, non-collinear spin textures. For example, kagome arrays of inplane magnetized nano-islands do not show magnetic order. Instead, these systems are characterized by spin textures with intriguing properties, such as chirality, coexistence of magnetic order and disorder, and charge crystallization. Magnetic frustration effects in lithographically patterned kagome arrays of nanomagnets with out-of-plane magnetization also lead to an unusal, and still unknown, magnetic ground state manifold. Besides the influence of the lattice geometry, the micromagnetic nature of the elements constituting the arrays introduce the concept of chiral magnetic monopoles, bringing additional complexity into the physics of artificial frustrated spin systems.

  9. Artificial Immune Systems Tutorial

    CERN Document Server

    Aickelin, Uwe

    2008-01-01

    The biological immune system is a robust, complex, adaptive system that defends the body from foreign pathogens. It is able to categorize all cells (or molecules) within the body as self-cells or non-self cells. It does this with the help of a distributed task force that has the intelligence to take action from a local and also a global perspective using its network of chemical messengers for communication. There are two major branches of the immune system. The innate immune system is an unchanging mechanism that detects and destroys certain invading organisms, whilst the adaptive immune system responds to previously unknown foreign cells and builds a response to them that can remain in the body over a long period of time. This remarkable information processing biological system has caught the attention of computer science in recent years. A novel computational intelligence technique, inspired by immunology, has emerged, called Artificial Immune Systems. Several concepts from the immune have been extracted an...

  10. Artificial Immune Systems

    CERN Document Server

    Aickelin, Uwe

    2009-01-01

    The biological immune system is a robust, complex, adaptive system that defends the body from foreign pathogens. It is able to categorize all cells (or molecules) within the body as self-cells or non-self cells. It does this with the help of a distributed task force that has the intelligence to take action from a local and also a global perspective using its network of chemical messengers for communication. There are two major branches of the immune system. The innate immune system is an unchanging mechanism that detects and destroys certain invading organisms, whilst the adaptive immune system responds to previously unknown foreign cells and builds a response to them that can remain in the body over a long period of time. This remarkable information processing biological system has caught the attention of computer science in recent years. A novel computational intelligence technique, inspired by immunology, has emerged, called Artificial Immune Systems. Several concepts from the immune have been extracted an...

  11. Natural and Artificial Radioactivity in Drinkingwater in Malaga, Spain

    International Nuclear Information System (INIS)

    The measurement of radioactivity in drinking water permits us to determine the exposure of the population to radiation from the habitual consumption of water. An intensive study of the water supply in the city of Malaga during 2002-2010 has been carried out in order to determine the gross alpha and gross beta activities and natural and artificial radionuclides present in drinking water. A database on natural and artificial radioactivity in water was created. The results indicated that a high percentage of the water sample contains a total gross alpha and beta concentration of less than 0.10 Bq/L and 1 Bq/L, respectively. The main objectives were: (1) to analyse gross alpha and gross beta activities and to know the statistical distributions; (2) to study the levels of natural and artificial radionuclides; (3) to determine a possible mathematical correlation between the radionuclides and several factors. (author)

  12. Effective ultraviolet irradiance measurements from artificial tanning devices in Greece.

    Science.gov (United States)

    Petri, Aspasia; Karabetsos, Efthymios

    2015-12-01

    Artificial tanning remains very popular worldwide, despite the International Agency for Research on Cancer classification of ultraviolet (UV) radiation from sunbeds as 'carcinogenic to humans'. Greek Atomic Energy Commission has initiated a surveillance action of the artificial tanning devices in Greece in order to record the effective irradiance levels from the sunbeds and to inform and synchronise the domestic artificial tanning business sector with the requirements of the European Standard EN 60335-2-27:2010. In this direction, in situ measurements of UV emissions from sunbeds in solaria businesses all over Greece were performed from October 2013 until July 2014, with a radiometer and a portable single-monochromator spectrophotometer. Analysis of the measurements' results revealed that effective irradiance in ∼60 % of the measured sunbeds exceeded the 0.3 W m(-2) limit value set by EN 60335-2-27:2010 and only 20 % of the devices could be categorised as UV type 3. PMID:25468991

  13. Development of Abdominal Compression Belt and Evaluation of the Efficiency for the Reduction of Respiratory Motion in SBRT

    International Nuclear Information System (INIS)

    It's essential to minimize the tumor motion and identify the exact location of the lesions to achieve the improvement in radiation therapy efficiency during SBRT. In this study, we made the established compression belt to reduce respiratory motion and evaluated the usefulness of clinical application in SBRT. We analyzed the merits and demerits of the established compression belt to reduce the respiratory motion and improved the reproducibility and precision in use. To evaluate the usefulness of improved compression belt for respiratory motion reduction in SBRT, firstly, we reviewed the spiral CT images acquired in inspiration and expiration states of 8 lung cancer cases, respectively, and analyzed the three dimensional tumor motion related to respiration. To evaluate isodose distribution, secondly, we also made the special phantom using EBT2 film (Gafchronic, ISP, USA) and we prepared the robot (Cartesian Robot-2 Axis, FARARCM4H, Samsung Mechatronics, Korea) to reproduce three dimensional tumor motion. And analysis was made for isodose curves and two dimensional isodose profiles with reproducibility of respiratory motion on the basis of CT images. A respiratory motion reduction compression belt (Velcro type) that has convenient use and good reproducibility was developed. The moving differences of three dimensional tumor motion of lung cancer cases analyzed by CT images were mean 3.2 mm, 4.3 mm and 13 mm each in LR, AP and CC directions. The result of characteristic change in dose distribution using the phantom and rectangular coordinates robot showed that the distortion of isodose has great differences, mean length was 4.2 mm; the differences were 8.0% and 16.8% each for cranio-caudal and 8.1% and 10.9% each for left-right directions in underdose below the prescribed dose. In this study, we could develop the convenient and efficient compression belt that can make the organs' motion minimize. With this compression belt, we confirmed that underdose due to respiration

  14. Ultraviolet radiation, sun and tanning salons

    CERN Document Server

    1999-01-01

    The pamphlet gives some information about ultraviolet radiation (UV), UV-sources and health effects, tanning in artificial and natural sun. It also includes some sun protection advice. It is intended mainly for persons inspecting artificial tanning units and for the owners of tanning salons. (Author)

  15. Measurement of charge composition of electron flows with an energy above hundreds MeV in inner radiaion belt

    International Nuclear Information System (INIS)

    A detector for studying the charge composition of a high-energy electron component of an internal radiation belt when measuring the precipitation of charged particles in the region of Brazil magnetic anomaly is suggested. The detector is a telescope consisting of two semiconductors and CsI crystal housed into a protection detector in the form of a cup made of plastic scintillator. An absorber of plastic scintillator is placed between semiconductive detections. The detector may record positrons with energy up to 5 MeV in the composition of precipitating particles from the belt in definite detector signal combination and specific energy release 511 keV in CsI crystal. 16 refs.; 3 figs

  16. Artificial Life Meets Computational Creativity?

    OpenAIRE

    McMullin, Barry

    2009-01-01

    I (briefly) review the history of work in Artificial Life on the problem of the open-ended evolutionary growth of complexity in computational worlds. This is then put into the context of evolutionary epistemology and human creativity.

  17. Darwin, artificial selection, and poverty.

    Science.gov (United States)

    Sanchez, Luis

    2010-03-01

    This paper argues that the processes of evolutionary selection are becoming increasingly artificial, a trend that goes against the belief in a purely natural selection process claimed by Darwin's natural selection theory. Artificial selection is mentioned by Darwin, but it was ignored by Social Darwinists, and it is all but absent in neo-Darwinian thinking. This omission results in an underestimation of probable impacts of artificial selection upon assumed evolutionary processes, and has implications for the ideological uses of Darwin's language, particularly in relation to poverty and other social inequalities. The influence of artificial selection on genotypic and phenotypic adaptations arguably represents a substantial shift in the presumed path of evolution, a shift laden with both biological and political implications. PMID:20812798

  18. Artificial Reefs and Ocean Dumping.

    Science.gov (United States)

    Glueck, Richard D.

    1983-01-01

    Activities and instructional strategies for two multigrade lessons are provided. Activity objectives include describing an artificial reef (such as a sunken ocean liner) as an ecosystem, knowing animal types in the ecosystem, and describing a food web. (JN)

  19. Artificial Intelligence in Civil Engineering

    Directory of Open Access Journals (Sweden)

    Pengzhen Lu

    2012-01-01

    Full Text Available Artificial intelligence is a branch of computer science, involved in the research, design, and application of intelligent computer. Traditional methods for modeling and optimizing complex structure systems require huge amounts of computing resources, and artificial-intelligence-based solutions can often provide valuable alternatives for efficiently solving problems in the civil engineering. This paper summarizes recently developed methods and theories in the developing direction for applications of artificial intelligence in civil engineering, including evolutionary computation, neural networks, fuzzy systems, expert system, reasoning, classification, and learning, as well as others like chaos theory, cuckoo search, firefly algorithm, knowledge-based engineering, and simulated annealing. The main research trends are also pointed out in the end. The paper provides an overview of the advances of artificial intelligence applied in civil engineering.

  20. Delivery of meteorites from the asteroid belt

    Science.gov (United States)

    Nolan, Michael Craig

    The process of the delivery of meteorites to the surface of the Earth from plausible source regions such as the asteroid belt is currently understood in general terms, but important uncertainties and conflicts remain to be resolved. Stochastic effects of the rare disruptions of large asteroids on the population of meteorite-sized Earth-crossing asteroids can change the flux and the proportions of compositional types in the infalling meteorite population. These changes can be significant in magnitude over timescales of 108 years. Changes of the order of 1 percent can be expected on timescales of 105-106 y, consistent with small differences between the Antarctic meteorites and modern falls. The magnitude of changes depends strongly on poorly-understood details of collisions. Asteroids 961 Gaspra and 243 Ida were recently imaged by the Galileo spacecraft. I use a numerical hydrocode model to examine the outcomes of various sire impacts into targets the sizes of these asteroids. A shock wave fractures the asteroid in advance of crater excavation flow; thus, for impactors larger than 100 m, impacting at 5.3 km s-1, tensile strength is unimportant in these bodies, whether they are initially intact or are 'rubble piles'. Because of the shock-induced fracture, impact results are controlled by gravity. Therefore these asteroids are much more resistant to catastrophic disruption than predicted by previous estimates, which had assumed that strength was controlling these processes for rock targets. Fracture of km-size asteroids is different from fracture in terrestrial experiments using few-cm targets. The composition distribution of delivered meteorites depends on the outcomes of such asteroid impacts.